China Product
Pathophysiology
Allergic urticaria on the back
The skin lesions of urticarial disease are caused by an inflammatory reaction in the skin, causing leakage of capillaries in the dermis, and resulting in an edema which persists until the interstitial fluid is absorbed into the surrounding cells. mens ski suit
Allergic urticaria on the skin induced by an antibiotic one piece ski suits
Urticaria are caused by the release of histamine and other mediators of inflammation (cytokines) from cells in the skin. This process can be the result of an allergic or non-allergic reaction, differing in the eliciting mechanism of histamine release. boxing shorts
Allergic urticaria on the arm
Allergic urticaria
Histamine and other pro-inflammatory substances are released from mast cells in the skin and tissues in response to the binding of allergen-bound IgE antibodies to high affinity cell surface receptors. Basophils and other inflammatory cells are also seen to release histamine and other mediators, and are thought to play an important role, especially in chronic urticarial diseases.
Autoimmune urticaria
In the past decade, it has been noted that many cases of chronic idiopathic urticaria are the result of an autoimmune trigger. For example, roughly one third of patients with chronic urticaria spontaneously develop auto-antibodies directed at the receptor FcRI located on skin mast cells. Chronic stimulation of this receptor leads to chronic hives. Patients often have other autoimmune conditions such as autoimmune thyroiditis.
Infectious
Hive-like rashes commonly accompany viral illnesses, such as the common cold. They usually appear 35 days after the cold has started, and may even appear a few days after the cold has resolved.
Non-allergic urticaria
Mechanisms other than allergen-antibody interactions are known to cause histamine release from mast cells. Many drugs, for example morphine, can induce direct histamine release not involving any immunoglobulin molecule. Also, a diverse group of signaling substances called neuropeptides have been found to be involved in emotionally induced urticaria. Dominantly inherited cutaneous and neurocutaneous porphyrias (porphyria cutanea tarda, hereditary coproporphyria, variegate porphyria and erythropoietic protoporphyria) have been associated with solar urticaria. The occurrence of drug-induced solar urticaria may be associated with porphyrias. This may be caused by IgG binding not IgE.
Dietary histamine poisoning
This is termed scombroid food poisoning. Ingestion of free histamine released by bacterial decay in fish flesh may result in a rapid-onset allergic-type symptom complex which includes urticaria. However, the urticaria produced by scromboid is reported not to include wheals.
Stress and chronic idiopathic urticaria
Chronic idiopathic urticaria has been anecdotally linked to stress since the 1940s. There is a large body of evidence demonstrating an association between this condition and both poor emotional well-being and reduced health related quality of life. More recent research has investigated hypotheses about stress as a causal factor in triggering the condition. Evidence has been found for a link between stressful life events (e.g. bereavement, divorce etc...) and preliminary evidence has been reported for a link between posttraumatic stress and chronic idiopathic urticaria. Less is known about the individual experiences and characteristics of people who develop chronic idiopathic urticaria following stress. Research into these factors in the relationship between stress and chronic idiopathic urticaria is ongoing by a number of researchers, including an online project currently being undertaken by researchers at the University of Plymouth.
Differential diagnosis
The rash that develops from poison ivy, poison oak, and poison sumac contact is commonly mistaken for urticaria. This rash is caused by contact with urushiol and results in a form of contact dermatitis called Urushiol-induced contact dermatitis. Urushiol is spread by contact, but can be washed off with a strong grease/oil dissolving detergent and cool water and rubbing ointments.
Types
Acute urticaria usually show up a few minutes after contact with the allergen and can last a few hours to several weeks. Food allergic reactions often fit in this category. The most common food allergies in adults are shellfish and nuts. The most common food allergies in children are shellfish, nuts, peanuts, eggs, wheat, and soy. It is uncommon for patients to have more than 2 true food allergies. A less common cause is exposure to certain bacteria, such as streptococcus or possibly Helicobacter pylori. In these cases, the hives may be exacerbated by other factors, such as those listed under Physical Urticarias below.
Chronic urticaria refers to hives that persists for 6 weeks or more. There are no visual differences between acute and chronic urticaria. Some of the more severe chronic cases have lasted more than 20 years. A survey indicated that chronic urticaria lasted a year or more in more than 50% of sufferers and 20 years or more in 20% of them. Of course this does mean that in almost half the people it clears up within a year and in 80% it clears up within 20 years or less.
Drug-induced urticaria has been known to result in severe cardiorespiratory failure. The anti-diabetic sulphonylurea glimepiride (trade name Amaryl), in particular, has been documented to induce allergic reactions manifesting as urticaria. Other cases include dextroamphetamine, aspirin, penicillin, clotrimazole, sulfonamides and anticonvulsants.
Physical urticarias are often categorized into the following.
Aquagenic: Reaction to water (exceedingly rare)
Cholinergic: Reaction to body heat, such as when exercising or after a hot shower
Cold (Chronic cold urticaria): Reaction to cold, such as ice, cold air or water - worse with sudden change in temperature
Delayed Pressure: Reaction to standing for long periods, bra-straps, elastic bands on undergarments, belts
Dermatographic: Reaction when skin is scratched (very common)
Heat: Reaction to hot food or objects (rare)
Solar: Reaction to direct sunlight (rare, though more common in those with fair skin)
Vibration: Reaction to vibration (rare)
Adrenergic: Reaction to adrenaline / noradrenaline (extremely rare)
Related conditions
Angioedema is similar to urticaria, but in angioedema, the swelling occurs in a lower layer of the dermis than it does in urticaria, as well as in the subcutis. This swelling can occur around the mouth, in the throat, in the abdomen, or in other locations. Urticaria and angioedema sometimes occur together in response to an allergen and is a concern in severe cases as angioedema of the throat can be fatal.
Urticaria can be a complication and symptom of a parasitic infection as Fascioliasis (Fasciola Hepatica)and Ascariasis (Ascaris Lumbricoides).[citation needed]
Management
Chronic urticaria can be difficult to treat. There are no guaranteed treatments or means of controlling attacks, and some sub-populations are treatment-resistant, with medications spontaneously losing their effectiveness and requiring new medications to control attacks. It can be difficult to determine appropriate medications since some, such as loratadine, require a day or two to build up to effective levels, and since the condition is intermittent and outbreaks typically clear up without any treatment.
Most treatment plans for urticaria involve being aware of one's triggers, but this can be difficult since there are several different forms of urticaria and people often exhibit more than one type. Also, since symptoms are often idiopathic (unknown reason) there might not be any clear trigger. If one's triggers can be identified then outbreaks can often be managed by limiting one's exposure to these situations.
Histamine antagonists
Drug treatment is typically in the form of antihistamines such as diphenhydramine, hydroxyzine, cetirizine and other H1 receptor antagonists. These are taken on a regular basis to protective effect, lessening or halting attacks. While the disease may be physiological in origin, psychological treatments such as stress management can sometimes lessen severity and occurrence. Additionally, methods similar to psychological pain management can be used to shift focus away from the discomfort and itchiness during an attack.
The H2-receptor antagonists such as cimetidine and ranitidine may help control symptoms either prophylactically or by lessening symptoms during an attack. When taken in combination with a H1 antagonist it has been shown to have a synergistic effect which is more effective than either treatment alone.[citation needed] The use of ranitidine (or other H2 antagonist) for urticaria is considered an off-label use, since these drugs are primarily used for the treatment of peptic ulcer disease and gastroesophageal reflux disease.
Other
Tricyclic antidepressants, such as doxepin, also are often potent H1 and H2 antagonists and may have a role in therapy, although side effects limit their use. For very severe outbreaks, an oral corticosteroid such as Prednisone is sometimes prescribed. However this form of treatment is controversial because of the extensive side effects common with corticosteroids and as such is not a recommended long-term treatment option.
As of 2008 an Australian company is performing clinical trials with an analogue of alpha-melanocyte-stimulating hormone called afamelanotide (formerly CUV1647) for the treatment of solar urticaria, a type of urticaria that develops in response to exposure to specific wavelengths of light.
Dietary
Children with intermittent or recurrent urticaria-angiodema were fed 7 food-additives: tartrazine (E102), sunset yellow (E110), erythrosine (E127), annatto (E160b), sodium benzoate (E211), acetyl-salicylic acid (ASA), and aspartame. Reactions to the food additives were common: E102 = 50%, E110 = 64%, E127 = 35%, E160b = 60%, E211: 57%; ASA = 12%, aspartame = 48%. The authors suggest that food additive intolerance is frequent in children with recurrent or intermittent urticaria-angiodema, and that aspartame may contribute directly to urticaria-angiodema in childhood.
See also
Wheals
Acute urticaria
Chronic urticaria
Anti-itch drug
Chronic cold urticaria
Urticaria pigmentosa
Cholinergic urticaria
Maculopapular rash
kallikrein
List of cutaneous conditions
Virus identified as likely cause[citation needed]
References
^ "urticaria" The Oxford English Dictionary. 2nd ed. 1989. OED Online. Oxford University Press. 2 May 2009.
^ http://dermnetnz.org/reactions/scombroid.html
^ Mitchell, J., Curran, C., and Myers, R. (1947) Some Psychosomatic Aspects of Allergic Diseases. Psychosomatic Medicine: 9(3), 184-191. .
^ Uguz, F., Engin, B., and Yilmaz, E. (2008a) Axis I and Axis II diagnoses in patients with chronic idiopathic urticaria. Journal of Psychosomatic Research, 64: 225-229. .
^ Engin, B., Uguz, F., Yilmaz, E., zdemir, M., and Mevlitoglu, I. (2007) The levels of depression, anxiety and quality of life in patients with chronic idiopathic urticaria. Journal of the European Academy of Dermatology and Venereology, 22(1): 36-40. .
^ Yang, H., Sun, C., Wu, Y., and Wang, J. (2005) Stress, insomnia, and chronic idiopathic urticaria: a case-control study. Journal of the Formos Medical Association, 104(4): 254-263. .
^ Chung, M., Symons, C., Gilliam, J., and Kaminski, E. (2008b) The relationship between post-traumatic stress resulting from past traumas, coping strategies and chronic idiopathic urticaria (CIU). Poster presented at the British Psychological Society Annual Conference.
^ Life Events and Chronic Idiopathic Urticaria research project, University of Plymouth, England. .
^
^ Tebbe B, Geilen CC, Schulzke JD, Bojarski C, Radenhausen M, Orfanos CE (April 1996). "Helicobacter pylori infection and chronic urticaria". J. Am. Acad. Dermatol. 34 (4): 6856. doi:10.1016/S0190-9622(96)80086-7. PMID 8601663. http://linkinghub.elsevier.com/retrieve/pii/S0190-9622(96)80086-7.
^ Champion RH, Roberts SO, Carpenter RG, Roger JH (1969). "Urticaria and angio-oedema. A review of 554 patients". Br. J. Dermatol. 81 (8): 58897. doi:10.1111/j.1365-2133.1969.tb16041.x. PMID 5801331.
^ "Prescribing Information Dexedrine". GlaxoSmithKline. June 2006. http://dailymed.nlm.nih.gov/dailymed/fdaDrugXsl.cfm?id=1215&type=display.
^ angioedema at Dorland's Medical Dictionary
^ "Hives (Urticaria and Angioedema)". 2006-03-01. http://www.webmd.com/allergies/guide/hives-urticaria-angioedema. Retrieved 2007-08-24.
^ Greaves MW, Tan KT (2007). "Chronic Urticaria: Recent Advances". Clin Rev Allergy Immunol 33 (1-2): 134143. doi:10.1007/s12016-007-0038-3. PMID 18094952.
^ Lee EE, Maibach HI (2001). "Treatment of urticaria. An evidence-based evaluation of antihistamines". Am J Clin Dermatol 2 (1): 2732. doi:10.2165/00128071-200102010-00005. PMID 11702618.
^ "World Health Organisation assigns CUV1647 generic name" (PDF). Clinuvel. 2008. http://www.clinuvel.com/resources/pdf/asx_announcements/2008/20080617WHOGenericName.pdf. Retrieved 2008-06-17.
^ McDonald, Kate (2007-04-13). "Tackling skin cancer in organ transplant patients". Australian Life Scientist. http://www.biotechnews.com.au/index.php/id;444900667. Retrieved 2007-12-24.
^ "Clinuvel gets green light". Biotechnews.com.au (LifeScientist). 2007-06-11. http://www.biotechnews.com.au/index.php/id;1708412693;fp;16;fpid;1. Retrieved 2008-06-13.
^ Baron, ED; Taylor, CR (2007-03-29). "Urticaria, Solar". WebMD. http://www.emedicine.com/derm/topic448.htm. Retrieved 2007-12-26.
^ de Martino M, Peruzzi M, Galli L, Lega L, Zammarchi E, Vierucci A (1992). "Food-additive intolerance and its correlation with atopy in children with recurrent or intermittent urticaria-angioedema". Pediatric Allergy and Immunology 3 (1): 3338. doi:10.1111/j.1399-3038.1992.tb00024.x. http://www3.interscience.wiley.com/journal/119332669/abstract.
External links
Urticaria photo library at Dermnet
v d e
Diseases of the skin and appendages by morphology
Growths
Epidermal
wart callus seborrheic keratosis acrochordon molluscum contagiosum actinic keratosis squamous cell carcinoma basal cell carcinoma merkel cell carcinoma nevus sebaceous trichoepithelioma
Pigmented
Freckles lentigo melasma nevus melanoma
Dermal and
subcutaneous
epidermal inclusion cyst hemangioma dermatofibroma keloid lipoma neurofibroma xanthoma Kaposi's sarcoma infantile digital fibromatosis granular cell tumor leiomyoma lymphangioma circumscriptum myxoid cyst
Rashes
With
epidermal
involvement
Eczematous
contact dermatitis atopic dermatitis seborrheic dermatitis stasis dermatitis lichen simplex chronicus Darier's disease glucagonoma syndrome langerhans cell histiocytosis lichen sclerosus pemphigus foliaceus Wiskott-Aldrich syndrome Zinc deficiency
Scaling
psoriasis tinea (corporis cruris pedis manuum faciei) pityriasis rosea secondary syphillis mycosis fungoides systemic lupus erythematosus pityriasis rubra pilaris parapsoriasis ichthyosis
Blistering
herpes simplex herpes zoster varicella bullous impetigo acute contact dermatitis pemphigus vulgaris bullous pemphigoid dermatitis herpetiformis porphyria cutanea tarda epidermolysis bullosa simplex
Papular
scabies insect bite reactions lichen planus miliaria keratosis pilaris lichen spinulosus transient acantholytic dermatosis lichen nitidus pityriasis lichenoides et varioliformis acuta
Pustular
acne vulgaris acne rosacea folliculitis impetigo candidiasis gonococcemia dermatophyte coccidioidomycosis subcorneal pustular dermatosis
Hypopigmented
tinea versicolor vitiligo pityriasis alba postinflammatory hyperpigmentation tuberous sclerosis idiopathic guttate hypomelanosis leprosy hypopigmented mycosis fungoides
Without
epidermal
involvement
Red
Blanchable
Erythema
Generalized
drug eruptions viral exanthems toxic erythema systemic lupus erythematosus
Localized
cellulitis abscess boil erythema nodosum carcinoid syndrome fixed drug eruption
Specialized
urticaria erythema (multiforme migrans gyratum repens annulare centrifugum ab igne)
Nonblanchable
Purpura
Macular
thrombocytopenic purpura actinic purpura
Papular
disseminated intravascular coagulation vasculitis
Indurated
scleroderma/morphea granuloma annulare lichen sclerosis et atrophicus necrobiosis lipoidica
Miscellaneous
disorders
Ulcers
Hair
telogen effluvium androgenic alopecia trichotillomania alopecia areata systemic lupus erythematosus tinea capitis loose anagen syndrome lichen planopilaris folliculitis decalvans acne keloidalis nuchae
Nail
onychomycosis psoriasis paronychia ingrown nail
Mucous
membrane
aphthous stomatitis oral candidiasis lichen planus leukoplakia pemphigus vulgaris mucous membrane pemphigoid cicatricial pemphigoid herpesvirus coxsackievirus syphilis systemic histoplasmosis squamous cell carcinoma
v d e
Diseases of the skin and subcutaneous tissue (integumentary system) (L, 680-709)
Infections
Bacterial
skin disease
Staphylococcus (Staphylococcal scalded skin syndrome, Impetigo, Boil, Carbuncle) Strep (Impetigo) Corynebacterium (Erythrasma)
Viral
skin disease
Wart Molluscum contagiosum Erythema infectiosum Exanthema subitum Herpes simplex (Herpetic whitlow, Eczema herpeticum)
General
Cellulitis (Paronychia) Acute lymphadenitis Pilonidal cyst Pimple (Pustule)
Bullous
disorders
acantholysis (Pemphigus, Transient acantholytic dermatosis) Pemphigoid (Bullous, Cicatricial, Gestational) Dermatitis herpetiformis
Inflammatory
Dermatitis
and eczema
Atopic dermatitis Seborrhoeic dermatitis (Dandruff, Cradle cap) Contact dermatitis (Diaper rash, Urushiol-induced contact dermatitis) Erythroderma Lichen simplex chronicus/Prurigo nodularis Itch (Pruritus ani, Pruritus scroti, Pruritus vulvae) Nummular dermatitis Dyshidrosis Pityriasis alba
Papulosquamous
disorders
Psoriasis (Psoriatic arthritis) Parapsoriasis (Pityriasis lichenoides et varioliformis acuta, Pityriasis lichenoides chronica, Lymphomatoid papulosis) other pityriasis (Pityriasis rosea, Pityriasis rubra pilaris) other lichenoid (Lichen planus, Lichen nitidus)
Urticaria
Dermatographic urticaria Cold urticaria Cholinergic urticaria Solar urticaria
Erythema
Erythema multiforme/
drug eruption
Stevens-Johnson syndrome Toxic epidermal necrolysis Erythema nodosum Acute generalized exanthematous pustulosis
Other erythema
Erythema annulare centrifugum Erythema marginatum Keratolytic winter erythema Necrolytic migratory erythema Erythema toxicum
Radiation-related
disorders
Sunburn actinic rays (Actinic keratosis, Actinic cheilitis) Polymorphous light eruption (Acne aestivalis) Radiodermatitis Erythema ab igne
Pigmentation/
Dyschromia
hypopigmentation (Albinism, Vitiligo) hyperpigmentation (Melasma, Freckle, Caf au lait spot, Lentigo/Liver spot, Acanthosis nigricans, Acral acanthotic anomaly)
Other skin
keratosis/hyperkeratosis (Seborrheic keratosis, Callus) other epidermal thickening (Ichthyosis acquisita, Palmoplantar keratoderma)
skin ulcer (Pyoderma gangrenosum, Bedsore)
Cutaneous Markers of Internal Malignancy (Florid cutaneous papillomatosis, acanthosis nigricans, sign of Leser-Trelat)
atrophic (Lichen sclerosus, Acrodermatitis chronica atrophicans)
necrobiosis (Granuloma annulare, Necrobiosis lipoidica) other granuloma (Granuloma faciale, Pyogenic granuloma)
cutaneous vasculitis (Livedoid vasculitis, Erythema elevatum diutinum)
Connective
tissues
collagen disease: Keloid
localized connective tissue disorders: Lupus erythematosus (Discoid lupus erythematosus, Subacute cutaneous lupus erythematosus) Scleroderma/Morphea Linear scleroderma Calcinosis cutis Sclerodactyly Ainhum
integument, SF, LCT navs: anat/physio, noncongen/congen/neoplasia, symptoms+signs/eponymous, proc
v d e
Immune disorders: hypersensitivity and autoimmune diseases
Type I/allergy/atopy
(IgE)
Foreign
Atopic dermatitis Allergic urticaria Hay fever Allergic asthma Anaphylaxis Food allergy (Milk, Egg, Peanut, Tree nut, Seafood, Soy, Wheat), Penicillin allergy
Autoimmune
none
Type II/ADCC
(IgM, IgG)
Foreign
Pernicious anemia Hemolytic disease of the newborn
Autoimmune
Cytotoxic
Autoimmune hemolytic anemia Idiopathic thrombocytopenic purpura Bullous pemphigoid Pemphigus vulgaris Rheumatic fever Goodpasture's syndrome
"Type 5"/receptor
Graves' disease Myasthenia gravis
Type III
(Immune complex)
Foreign
Henoch-Schnlein purpura Hypersensitivity vasculitis Reactive arthritis Rheumatoid arthritis Farmer's lung Post-streptococcal glomerulonephritis Serum sickness Arthus reaction
Autoimmune
Systemic lupus erythematosus Subacute bacterial endocarditis
Type IV/cell-mediated
(T-cells)
Foreign
Contact dermatitis Mantoux test
Autoimmune
Diabetes mellitus type 1 Hashimoto's thyroiditis Guillainarr syndrome Multiple sclerosis Coeliac disease Giant cell arteritis
GVHD
Transfusion-associated graft versus host disease
Unknown/
multiple
Foreign
Hypersensitivity pneumonitis (Allergic bronchopulmonary aspergillosis) Transplant rejection Latex allergy (I+IV)
Autoimmune
Sjgren's syndrome Autoimmune hepatitis Autoimmune polyendocrine syndrome (APS1, APS2) Autoimmune adrenalitis
lymphocyte navs: cells/physio, immunodeficiency/immunoproliferative immunoglobulin/neoplasia, proc
Categories: Urticaria and angioedemaHidden categories: All articles with unsourced statements | Articles with unsourced statements from November 2009 | Articles with unsourced statements from December 2007 | Articles with unsourced statements from June 2009
Friday, April 23, 2010
Urticaria
University of Osuna
China Product
The old university
The University of Osuna was founded based on a bull of Pope Paul III, and it was a peer university to the likes of the universities of Alcal de Henares, Bologna, or Salamanca. That bull was granted due to the efforts of Don Juan Tllez Girn, Fourth Count of Urea and First Duke of Osuna, who also gave it an endowment sufficient to its needs. Authorization for the university came directly from the pope without any specific involvement of the Spanish monarchy.
The University of Osuna had a system of scholarships, a residential hall for its students, and even its own burial ground. There were fifteen major professorial chairs in the university and eight lesser chairs in the associated college; these were grouped into faculties of Medicine, Law, Canon Law, Theology, and Arts. Of these, Theology was the most attended. Medical instruction was entirely theoretical: there was no operating theater. Philip II later added a chair in Mathematics. upvc windows and doors
The first rector was Francisco Maldonado; the last was Diego Ramirez. Dominicans, Augustinians, Franciscans, and Carmelites all taught at the university. awning windows
While one could get an excellent education at the old University of Osuna, one could also drift through, attend classes in a desultory manner, and add an academic degree to his name, as long as the fees were paid (supplemented by "propinas", tips, if one's academic performance were truly poor). Osuna was not unique among Spanish universities of its time in this respect, but it was often singled out as an example. Cervantes, whose grandfather served as corregidor of Osuna, mentions the university three times in his writings, never favorably. Writing a century and a half later, Diego de Torres Villarroel, a professor at the University of Salamanca, described the granting of degrees by the University of Osuna, as well as at the universities of Sigenza and Irache, as amounting to "civil simony". japanese roof tile
Partly for these reasons, the University of Osuna narrowly escaped closure by Charles III in 1771 and was one of eleven universities closed in the reform of 1807. Its prerogatives were granted to the University of Seville. The university did not quite close down at this time, though its operations do seem to have been suspended when the building was used as a French headquarters during the Peninsular War. After the war, the university continued precariously until its definitive closure in 1824.
Student body
There were three types of students at the university: colegiales, sopistas, and mantestas.
As elsewhere in Spain in that era, the privileged colegiales were a social class apart, a student elite guaranteed housing and food, and virtually guaranteed a more or less brilliant future. At its establishment, Osuna set aside funding for twenty colegiales: six in theology, six in canon law, four in civil law, and four in medicine. This number proved excessively ambitious: neither the University of Seville nor the University of Granada ever hosted so many colegiales, and, in practice, neither did Osuna: the largest number ever at one time was eight, in 1596.
Positions were also endowed for 36 sopistas or capigorrones (the names mean, respectively, "eaters of thin soup" and "layabouts"), 12 each in grammar, arts, theology. These positionsgain, as in other Spanish univerities of the timeere reserved for poor young men of ability; they received a modest scholarship and their bread and board. It is not known how many sopistas actually attended the university, though there is a building near the university that tradition says was the "soup house" where they took meals. The degree of their poverty can be ascertained in part from a specific provision to supply them with shoes. These positions were set aside not so much to aid social mobility as because these graduates often reflected so well on the university. Their cuchara al cinturn ("spoon on the belt") remains a symbol of the tuna (a type of student troubadour) down to this day.
Finally, there were the ordinary students, the mantestas ("day students"). Some of these were natives of Osuna or nearby towns under the seigneury of the same duke, and lived with their families or in rented rooms. The majority had taken religious orders and lived in their convents. The records show the rectors of the university having to involve themselves in numerous cases where a mantesta failed to pay his rent, and no small number of mantestas impregnated a housemaid and took religious orders as an alternative to taking on other responsibilities.
As elsewhere in Spain, students were often disorderly: street riots were not uncommon, especially among those who were living in poverty to the point of hunger. In many cases, the student class could not be distinguished readily from that of vagrants, beggars, and thieves. Such conduct by some of the students often made the studies of the more responsible students difficult. In 1782, the rector reminded the students to "abstain from throwing rocks, both inside and outside the university; from doing damage to the doors and buildings; from defacing the walls"
Notable graduates
Joseph Blanco White (Jos Mara Blanco White), poet, theologian.
Rodrigo Caro, poet, historian, archeologist, and lawyer.
Lus Vlez de Guevara, novelist and playwright, graduated in 1596
The present university
In 1995 the city of Osuna began the adaptation of the old university building for modern university-level classes. The Escuela Universitaria opened for the academic year 199697. As of 1999, the university was granting diplomas in Labor Relations, Business, and Health Sciences.
The building
Significance
The building of the former University of Osuna is significant both architecturally and for its long history as a the seat of the university from its construction in 1548 to its closure in 1824. Its construction was ordered by Don Juan Tllez Girn, founder of the university. The First Duke of Osuna was responsible for numerous buildings in his domain, nearly all of a religious character. The university building is, therefore, particularly notable as an essentially civil building devoted to education.
The buildings erected under the patronage of the First Duke of Osuna are important primarily because of the extraordinary effort made to adopt and diffuse new stylistic currents and ideas from the Italian architecture of the time. The Renaissance aspects of the buildings are patent, as is the relation to the ideology of humanism in a building expressly created as a center for modern education.
The surviving university building testifies to the Renaissance aesthetics, providing one of the most singular and defining architectural examples of Osuna's past greatness.
Exterior
The University building. In the background is La Colegiata: the Iglesia Colegial de Nuestra Seora de la Asuncin ("College Church of Our Lady of the Assumption").
The former University of Osuna is a rectangular two-story building organized around a square courtyard. Its architectural design is characterized by simplicity and severity of its straight lines. Its unique profile, having a tower at each of its four corners, each tower topped by a spire with a glazed ceramic coating, makes it one of the most emblematic buildings of the city.
The four exterior walls are of stone. Several rectangular linteled openings are placed symmetrically. The towers at the two corners in front are cylindrical. The cylinders each extend a full story above the building, and then are covered by polygonal spires. The other two towers, in the rear, are square, in the styel of buttresses; they extend to the same height as those in front, and their spires are pyramidal. The glazed ceramic coatings of the spires is in blue and white.
The principal faade faces southeast, and is ornamented ashlar stonework. On the right half of the upper story are two linteled window bays, flanked by half-columns, with a pediment above. The principal entrance, which gives access to the interior, is to the left of center. For roughly two thirds of its height, the door is flanked by columns, over which there is a semicircular arch. That entire assemblage is finished at the outer edge with molding, flanked on both sides by attached columns on a high base, over which is an entablature with pinnacles on either end. On the second story over the entrance is a niche with an statue of the Virgin Mary holding the baby Jesus. This, in turn, is flanked with columns and pinnacles, a miniature of the entrance below; a tondo above shows the anagram of the Virgin. Over this all, another semicircular arch is worked into the faade. There in another window bay in the upper story to the left of the entrance, similar to the two bays on the right. There are four smaller windows on the upper part of the ground floor.
Interior
In the interior, most of the original rooms have been adapted and transformed into modern classrooms devoid of any artistic and architectural interest. However, the southeast side of the building, where the main entrance is located, retains its original structure, as do the gateway, the chapel, the Sala de la Girona ("Hall of Girona"), the central courtyard, the staircase leading upstairs and the old library.
Vestibule
One enters through the principal doorway to a rectangular vestibule or hall with a carved ceiling with two orders of beams on corbels, decorated with inlay work. This space opens on the right to the chapel, straight ahead to the central courtyard, and on the left to the Sala de la Girona.
Chapel
The chapel is rectangular, again with a carved ceiling with two orders of beams in the Plateresque style. Immediately above the entry is the choir loft, whose carved ceiling has a single order of beams. The center of this ceiling is decorated with Plateresque motifs alternating with tracery and pineapples. Over this ceiling is the rostrum of the upper choir, composed of a sill of wooden balusters.
The presbytery is raised above the rest of the chapel and at its head sits a neoclassical altarpiece with paintings that date back to a former Renaissance altarpiece. It is separated from the nave by a bay, which is segmented by a 16th century wrought-iron grating composed of two horizontal bands that divide the two areas. These bands have Renaissance-era decoration with a motif of flaming golden scrolls. Between the two bands are bent vertical bars thatn the lower central areapen to provide access to the chapel. At the top of the grating is a crest composed of semicircles made of bent bars, pointed and crowned with heraldic motifs, configured as an entablature.
The pulpit, made of wood, is on the left wall of the chapel. It consists of an access staircase with a sill of balustrades, a rectangular floor affixed to the wall like a balcony, and a semicircular bay embedded in the wall, under a triangular pediment topped with a cross.
Sala de la Girona
The Sala de la Girona is roughly rectangular, with a carved ceiling with two orders of beams over corbels. The upper part of its cladding is covered with murals painted in the second half of the 16th century. In the front end wall is a mural of the Virgin Mary enthroned with the baby Jesus on her lap; on both sides are groups of angels who giving him presents, as well as symbols related to the iconology of the Virgin. The composition is framed between drapes held back by angels, revealing an architectural background.
On the right wall the four church fathers are represented, each seated on a chair and surrounded by books scattered on the ground. From left to right they are Saint Jerome, Saint Gregory, Saint Ambrose and Saint Augustine, dressed according to the traditional iconography of these saints, each holding a staffs and a model of the church in one hand while the other shows the pen as a symbol of scripture. The composition is completed with architectural backgrounds and at the bottom with the names of each character written in classical characters on phylacteries.
The mural on the wall facing the one previously described represents the Four Evangelists seated on a marble bench. From left to right are Saint Mark, Saint Luke, Saint John and Saint Matthew, each of them with his symbol. The last of the murals is on the front door. It presents a courtly scene in an imaginary rural landscape. A palatial building is surrounded by large trees and a river. Most the prominent focus is a hunting scene of galloping horsemen, but there are also shepherds and dogs caring for their herd. Analysis of the forms and the garments of the characters indicate has shown that the work dates from the early 18th century.
Courtyard or patio
The central courtyard (Spanish: patio) is rectangular, two stories high, with a double arcade on all four sides. The lower floor features marble columns of the Tuscan order, supporting paired, symmetrical semicircular bays. Above the columns are located small pillars that, at their connection to the entablature, form an alfiz, a type of arch characteristic of Morisco architecture. The upper galleries are composed of columns on high plinths, supporting semicircular bays, paired and covered with iron railings. In the center of the courtyard stands a well with a stone curb.
The staircase rises from the southeast side of the courtyard. Three flights of stairs occupy a rectangular space. The stairs are covered by a barrel vault whose cladding is decorated with octagonal coffers.
Library
The former librarys of 2004 an assembly hallits over the chapel and the principal entrance. It is reached through the gallery of the courtyard, at the top of the staircase. It is rectangular, covered with very elongated trough-shaped armature.
Paintings
In addition to the murals mentioned above and the paintings of the four church fathers and the Four Evangelists, the building also has paintings of the Immaculate Conception, Annunciation, Nativity, and Epiphany and several portraits, including two each of Don Juan Tllez Girn and Doa Mara de la Cueva.
Use of the building after 1824
The fate of the building between 1824 and 1847 is unknown. The Law of Public Instruction of 17 September 1845 established Institutos de Segunda Enseanza (roughly high schools or secondary schools). The old university reopened in 1847 as such an institute, and operated in that capacity until 1993, when it moved to a former old age home restored and adapted by the Council of Education of the Andalusian Autonomous Government.
Since 1995, the building has again been the site of university-level instruction, in the form of the Escuela Universitaria. This required a comprehensive restoration. On the one hand, the building was renovated to resemble as closely as possible its historical appearance; on the other hand, electricity, sanitary facilities, and climatization were brought up to modern standards. The wooden portions of the building, especially the elaborate ceilings, were painstakingly restored, as was the tilework on the towers. One new emergency staircase was added at the corner of the courtyard opposite the historic staircase; an emergency exit was added at the back. An elevator was also added, adjacent to the new staircase.
During restoration, some interesting discoveries were made: the arrangement of openings to the courtyard had apparently been changed at least once in the course of the building's history. The decision was made to retain the longstanding configuration, rather than to restore an even earlier one.
Notes
^ a b c d e f g h i j k l m n o p q r s t u v DECRETO 346/2004, de 18 de mayo, por el que se declara bien de inters cultural, con la categora de monumento, el Colegio-Universidad de la Pursima Concepcin en Osuna (Sevilla). BOE, number 181, 2004-07-28
^ a b c d e f g h i Francisco Reyes, El Colegio-Universidad Osuna, Aparejadores (published by Colegio Oficial de Aparejadores y Arquitectos Tcnicos de Sevilla), Number 55 (TOC), May 1999. Accessed online 2010-02-07.
^ Alfonso Pozo Ruiz, El leitmotiv y patrimonio fundacional de la Universidad de Osuna. Accessed online 2010-02-07.
^ a b c d e f g h i j k Alfonso Pozo Ruiz, La antigua Universidad de Osuna (Sevilla). Accessed online 2010-02-07.
^ Alfonso Pozo Ruiz, La antigua Universidad de Osuna (Sevilla). Accessed online 2010-02-07. Pozo Ruiz gives Law and Canon Law as a single department, and adds Arts, which Reyes omits.
^ Alfonso Pozo Ruiz, La extincin de la Universidad de Osuna. Accessed online 2010-02-07.
^ a b c d e f Alfonso Pozo Ruiz, Los estudiantes universitarios de Osuna. Accessed online 2010-02-07.
^ Vicente Beltrn de Heredia (1973). Miscelnea Beltrn de Heredia: coleccin de artculos sobre historia de la teologa espaola, Volume 4. Editorial San Esteban. p. 362. ISBN 8471881233. http://books.google.com/books?id=XjFHzgeEKXcC&pg=PA362.
^ Jos Garca Mercadal (1954). Estudiantes, sopistas y pcaros. Buenos Aires: Espasa-Calpe.
^ Blanco White mentions his degree from Osuna in passing in his Practical and Internal Evidence Against Catholicism; a poor scan is available online at archive.org: "when I was not of sufficient standing [at Seville] for the superior degree of Licentiate of Divinity, which the Fellowship required, I took that degree at Osuna, where the statutes demand no interval between these academical honours."
^ Rodrigo Caro, Biografas y Vidas. Accessed online 2010-02-07.
^ a b "Vlez de Guevara, Lus", McGraw-Hill encyclopedia of world drama: an international reference work in 5 volumes (Second Edition), Volume 2, McGraw-Hill / Verlag fr die Deutsche Wirtschaft AG, 1984. ISBN 0070791694. p. 98.
References
Alfonso Pozo Ruiz, Historia de la Universidad de Sevilla. This is a re-working of materials Pozo Ruiz wrote for quintocentenario.us.es, the now-defunct official site of the 500th anniversary of the University of Seville; it contains significant material about the University of Osuna as well.
Pozo Ruiz's quintocentenario.us.es materials about the University of Osuna can still be accessed on the Internet Archive, although the images appear to be lost: see, for example Osuna home page as archived 2007-08-07. Links at bottom of that page lead to additional pages about the University of Osuna archived from that site.
External links
(Spanish) Francisco Reyes, El Colegio-Universidad Osuna, Aparejadores (published by Colegio Oficial de Aparejadores y Arquitectos Tcnicos de Sevilla), Number 55 (TOC), May 1999. Includes floor plans and a photo of the courtyard.
Categories: Universities in Andalusia | Defunct universities and colleges | 1548 establishments | 1824 disestablishments | Sevilla provinceHidden categories: Articles containing Spanish language text
Independent Spirit Award for Best First Feature
China Product
Winners and nominees
1980s
1987: She's Gotta Have It waterbed mattresses
A Great Wall intex bed
Belizaire the Cajun olympic queen mattress
Hoosiers
True Stories
1988: Dirty Dancing
Anna
Hollywood Shuffle
Siesta
Waiting for the Moon
1989: Mystic Pizza
Border Radio
The Prince of Pennsylvania
The Chocolate War
The Wash
1990s
1990: Heathers
84 Charlie Mopic
Powwow Highway
Sidewalk Stories
Talking To Strangers
1991: Metropolitan
House Party
Lightning Over Braddock
The Natural History of Parking Lots
Twister
1992: Straight Out of Brooklyn
Chameleon Street
Poison
Slacker
The Rapture
1993: The Waterdance
Laws of Gravity
My New Gun
Reservoir Dogs
Swoon
1994: El Mariachi
American Heart
Combination Platter
Mac
Menace II Society
1995: Spanking the Monkey
Clean, Shaven
Clerks
I Like It Like That
Suture
1996: The Brothers McMullen
Kids
Little Odessa
Picture Bride
River of Grass
1997: Sling Blade
Big Night
I Shot Andy Warhol
Manny & Lo
Trees Lounge
1998: Eve's Bayou
Hard Eight
In the Company of Men
Star Maps
The Bible And Gun Club
1999: The Opposite of Sex
Buffalo 66
High Art
Slums of Beverly Hills
2000s
2000: Being John Malkovich
Boys Don't Cry
Three Seasons
Twin Falls Idaho
Xiu Xiu: The Sent Down Girl
2001: You Can Count on Me
Boiler Room
Girlfight
Love & Basketball
The Visit
2002: In the Bedroom
Donnie Darko
Ghost World
The Anniversary Party
The Believer
2003: The Dangerous Lives of Altar Boys
Interview with the Assassin
Manito
Paid in Full
Roger Dodger
2004: Monster
Bomb the System
House of Sand and Fog
Quattro Noza
Thirteen
2005: Garden State
Brother to Brother
Napoleon Dynamite
Saints and Soldiers
The Woodsman
2006: Crash
Lackawanna Blues
Me and You and Everyone We Know
Thumbsucker
Transamerica
2007: Sweet Land
Day Night Day Night
Man Push Cart
The Motel
Wristcutters: A Love Story
2008: The Lookout
2 Days in Paris
Great World of Sound
Rocket Science
Vanaja
2009: Synecdoche, New York
Afterschool
Medicine for Melancholy
Sangre de Mi Madre
Sleep Dealer
2010: TBA
A Single Man
Crazy Heart
Easier With Practice
Paranormal Activity
The Messenger
v d e
Independent Spirit Awards
Current Awards
Best Film Best Actor Best Actress Best Supporting Actor Best Supporting Actress Best Director Best Cinematography Best Documentary Feature Best First Film Best Foreign Film Best Screenplay Best First Screenplay John Cassavetes Award
Ceremonies
1986 1987 1988 1989
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Categories: Independent Spirit Awards | Awards for best film
Nonlinear optics
China Product
Nonlinear optical processes
Nonlinear optics gives rise to a host of optical phenomena:
Frequency mixing processes flexo printing
Second harmonic generation (SHG), or frequency doubling, generation of light with a doubled frequency (half the wavelength) pvc card printer
Third harmonic generation (THG), generation of light with a tripled frequency (one-third the wavelength) (usually done in two steps: SHG followed by SFG of original and frequency-doubled waves) magnetic encoder
High harmonic generation (HHG), generation of light with frequencies much greater than the original (typically 100 to 1000 times greater)
Sum frequency generation (SFG), generation of light with a frequency that is the sum of two other frequencies (SHG is a special case of this)
Difference frequency generation (DFG), generation of light with a frequency that is the difference between two other frequencies
Optical parametric amplification (OPA), amplification of a signal input in the presence of a higher-frequency pump wave, at the same time generating an idler wave (can be considered as DFG)
Optical parametric oscillation (OPO), generation of a signal and idler wave using a parametric amplifier in a resonator (with no signal input)
Optical parametric generation (OPG), like parametric oscillation but without a resonator, using a very high gain instead
Spontaneous parametric down conversion (SPDC), the amplification of the vacuum fluctuations in the low gain regime
Optical rectification (OR), generation of quasi-static electric fields.
Other nonlinear processes
Optical Kerr effect, intensity dependent refractive index
Self-focusing
Kerr-lens modelocking (KLM)
Self-phase modulation (SPM), a (3) effect
Optical solitons
Cross-phase modulation (XPM)
Four-wave mixing (FWM), can also arise from other nonlinearities
Cross-polarized wave generation (XPW), a (3) effect in which a wave with polarization vector perpendicular to the input one is generated
Modulational instability
Raman amplification
Optical phase conjugation
Brillouin scattering, interaction of photons with acoustic phonons
Optical phase conjugation
Two-photon absorption, simultaneous absorption of two photons, transferring the energy to a single electron
Multiple photoionisation, near-simultaneous removal of many bound electrons by one photon
Chaos in Optical Systems
Related processes
In these processes, the medium has a linear response to the light, but the properties of the medium are affected by other causes:
Pockels effect, the refractive index is affected by a static electric field; used in electro-optic modulators;
Acousto-optics, the refractive index is affected by acoustic waves (ultrasound); used in acousto-optic modulators.
Raman scattering, interaction of photons with optical phonons;
Frequency-mixing processes
One of the most commonly-used frequency-mixing processes is frequency doubling or second-harmonic generation. With this technique, the 1064-nm output from Nd:YAG lasers or the 800-nm output from Ti:sapphire lasers can be converted to visible light, with wavelengths of 532 nm (green) or 400 nm (violet), respectively.
Practically, frequency-doubling is carried out by placing a special crystal in a laser beam under a well-chosen angle. Commonly-used crystals are BBO (-barium borate), KDP (potassium dihydrogen phosphate), KTP (potassium titanyl phosphate), and lithium niobate. These crystals have the necessary properties of being strongly birefringent (necessary to obtain phase matching, see below), having a specific crystal symmetry and of course being transparent for and resistant against the high-intensity laser light. However, organic polymeric materials are set to take over from crystals as they are cheaper to make, have lower drive voltages and superior performance.
Theory
A number of nonlinear optical phenomena can be described as frequency-mixing processes. If the induced dipole moments of the material respond instantaneously to an applied electric field, the dielectric polarization (dipole moment per unit volume) P(t) at time t in a medium can be written as a power series in the electrical field:
Here, the coefficients (n) are the n-th order susceptibilities of the medium. For any three-wave mixing process, the second-order term is crucial; it is only nonzero in media that have no inversion symmetry. If we write
where c.c. denotes the complex conjugate (E1 and E2 being the incident beams of interest), the second-order term in the above expansion will read
where the summation is over
The six combinations (nx,mx) correspond, respectively, to the second harmonic of E1, the second harmonic of E2, the optically rectified signals of E1 and E2, the difference frequency, and the sum frequency. A medium that is thus pumped by the fields E1 and E2 will radiate a field E3 with an angular frequency 3 = m11 + m22.
Note: in this description, (2) is a scalar. In reality, (2) is a tensor whose components depend on the combination of frequencies.
Parametric generation and amplification is a variation of difference frequency generation, where the lower-frequency one of the two generating fields is much weaker (parametric amplification) or completely absent (parametric generation). In the latter case, the fundamental quantum-mechanical uncertainty in the electric field initiates the process.
Phase matching
The above ignores the position dependence of the electrical fields. In a typical situation, the electrical fields are traveling waves described by
at position , with the wave vector , where c is the velocity of light and n(j) the index of refraction of the medium at angular frequency j. Thus, the second-order polarization angular frequency 3 is
At each position , the oscillating second-order polarization radiates at angular frequency 3 and a corresponding wave vector . Constructive interference, and therefore a high intensity 3 field, will occur only if
The above equation is known as the phase matching condition. Typically, three-wave mixing is done in a birefringent crystalline material (I.e., the refractive index depends on the polarization and direction of the light that passes through.), where the polarizations of the fields and the orientation of the crystal are chosen such that the phase-matching condition is fulfilled. This phase matching technique is called angle tuning. Typically a crystal has three axes, one or two of which have a different refractive index than the other one(s). Uniaxial crystals, for example, have a single preferred axis, called the extraordinary (e) axis, while the other two are ordinary axes (o) (see crystal optics). There are several schemes of choosing the polarizations for this crystal type. If the signal and idler have the same polarization, it is called "Type-I phase-matching", and if their polarizations are perpendicular, it is called "Type-II phase-matching". However, other conventions exist that specify further which frequency has what polarization relative to the crystal axis. These types are listed below, with the convention that the signal wavelength is shorter than the idler wavelength.
Phase-matching types
()
Polarizations
Scheme
Pump
Signal
Idler
e
o
o
Type I
e
o
e
Type II (or IIA)
e
e
o
Type III (or IIB)
e
e
e
Type IV
o
o
o
Type V
o
o
e
Type VI (or IIB or IIIA)
o
e
o
Type VII (or IIA or IIIB)
o
e
e
Type VIII (or I)
Most common nonlinear crystals are negative uniaxial, which means that the e axis has a smaller refractive index than the o axes. In those crystals, type I and II phasematching are usually the most suitable schemes. In positive uniaxial crystals, types VII and VIII are more suitable. Types II and III are essentially equivalent, except that the names of signal and idler are swapped when the signal has a longer wavelength than the idler. For this reason, they are sometimes called IIA and IIB. The type numbers VIII are less common than I and II and variants.
One undesirable effect of angle tuning is that the optical frequencies involved do not propagate collinearly with each other. This is due to the fact that the extraordinary wave propagating through a birefringent crystal possesses a Poynting vector that is not parallel with the propagation vector. This would lead to beam walkoff which limits the nonlinear optical conversion efficiency. Two other methods of phase matching avoids beam walkoff by forcing all frequencies to propagate at a 90 degree angle with respect to the optical axis of the crystal. These methods are called temperature tuning and quasi-phase-matching.
Temperature tuning is where the pump (laser) frequency polarization is orthogonal to the signal and idler frequency polarization. The birefringence in some crystals, in particular Lithium Niobate is highly temperature dependent. The crystal is controlled at a certain temperature to achieve phase matching conditions.
The other method is quasi-phase matching. In this method the frequencies involved are not constantly locked in phase with each other, instead the crystal axis is flipped at a regular interval , typically 15 micrometres in length. Hence, these crystals are called periodically-poled. This results in the polarization response of the crystal to be shifted back in phase with the pump beam by reversing the nonlinear susceptibility. This allows net positive energy flow from the pump into the signal and idler frequencies. In this case, the crystal itself provides the additional wavevector k=2/ (and hence momentum) to satisfy the phase matching condition. Quasi-phase matching can be expanded to chirped gratings to get more bandwidth and to shape an SHG pulse like it is done in a dazzler. SHG of a pump and Self-phase modulation (emulated by second order processes) of the signal and an optical parametric amplifier can be integrated monolithically.
Higher-order frequency mixing
The above holds for (2) processes. It can be extended for processes where (3) is nonzero, something that is generally true in any medium without any symmetry restrictions. Third-harmonic generation is a (3) process, although in laser applications, it is usually implemented as a two-stage process: first the fundamental laser frequency is doubled and then the doubled and the fundamental frequencies are added in a sum-frequency process. The Kerr effect can be described as a (3) as well.
At high intensities the Taylor series, which led the domination of the lower orders, does not converge anymore and instead a time based model is used. When a noble gas atom is hit by an intense laser pulse, which has an electric field strength comparable to the Coulomb field of the atom, the outermost electron may be ionized from the atom. Once freed, the electron can be accelerated by the electric field of the light, first moving away from the ion, then back toward it as the field changes direction. The electron may then recombine with the ion, releasing its energy in the form of a photon. The light is emitted at every peak of the laser light field which is intense enough, producing a series of attosecond light flashes. The photon energies generated by this process can extend past the 800th harmonic order up to 1300 eV. This is called high-order harmonic generation. The laser must be linearly polarized, so that the electron returns to the vicinity of the parent ion. High-order harmonic generation has been observed in noble gas jets, cells, and gas-filled capillary waveguides.
Optical phase conjugation
It is possible, using nonlinear optical processes, to exactly reverse the propagation direction and phase variation of a beam of light. The reversed beam is called a conjugate beam, and thus the technique is known as optical phase conjugation (also called time reversal, wavefront reversal and retroreflection).
One can interpret this nonlinear optical interaction as being analogous to a real-time holographic process. In this case, the interacting beams simultaneously interact in a nonlinear optical material to form a dynamic hologram (two of the three input beams), or real-time diffraction pattern, in the material. The third incident beam diffracts off this dynamic hologram, and, in the process, reads out the phase-conjugate wave. In effect, all three incident beams interact (essentially) simultaneously to form several real-time holograms, resulting in a set of diffracted output waves that phase up as the "time-reversed" beam. In the language of nonlinear optics, the interacting beams result in a nonlinear polarization within the material, which coherently radiates to form the phase-conjugate wave.
Comparison of a phase conjugate mirror with a conventional mirror. With the phase conjugate mirror the image is not deformed when passing through an aberrating element twice.
The most common way of producing optical phase conjugation is to use a four-wave mixing technique, though it is also possible to use processes such as stimulated Brillouin scattering. A device producing the phase conjugation effect is known as a phase conjugate mirror (PCM).
For the four-wave mixing technique, we can describe four beams (j = 1,2,3,4) with electric fields:
where Ej are the electric field amplitudes. 1 and 2 are known as the two pump waves, with 3 being the signal wave, and 4 being the generated conjugate wave.
If the pump waves and the signal wave are superimposed in a medium with a non-zero (3), this produces a nonlinear polarization field:
resulting in generation of waves with frequencies given by = 1 2 3 in addition to third harmonic generation waves with = 31, 32, 33.
As above, the phase-matching condition determines which of these waves is the dominant. By choosing conditions such that = 1 + 2 - 3 and k = k1 + k2 - k3, this gives a polarization field:
This is the generating field for the phase conjugate beam, 4. Its direction is given by k4 = k1 + k2 - k3, and so if the two pump beams are counterpropagating (k1 = -k2), then the conjugate and signal beams propagate in opposite directions (k4 = -k3). This results in the retroreflecting property of the effect.
Further, it can be shown for a medium with refractive index n and a beam interaction length l, the electric field amplitude of the conjugate beam is approximated by
(where c is the speed of light). If the pump beams E1 and E2 are plane (counterpropagating) waves, then:
that is, the generated beam amplitude is the complex conjugate of the signal beam amplitude. Since the imaginary part of the amplitude contains the phase of the beam, this results in the reversal of phase property of the effect.
Note that the constant of proportionality between the signal and conjugate beams can be greater than 1. This is effectively a mirror with a reflection coefficient greater than 100%, producing an amplified reflection. The power for this comes from the two pump beams, which are depleted by the process.
The frequency of the conjugate wave can be different from that of the signal wave. If the pump waves are of frequency 1 = 2 = , and the signal wave higher in frequency such that 3 = + , then the conjugate wave is of frequency 4 = - . This is known as frequency flipping.
Common SHG materials
Dark-Red Gallium Selenide in its bulk form.
806 nm light : lithium iodate (LiIO3)
860 nm light : potassium niobate (KNbO3)
980 nm light : KNbO3
1064 nm light : monopotassium phosphate (KH2PO4, KDP), lithium triborate (LBO) and -barium borate (BBO).
1300 nm light : gallium selenide (GaSe)
1319 nm light : KNbO3, BBO, KDP, potassium titanyl phosphate (KTP), lithium niobate (LiNbO3), LiIO3, and ammonium dihydrogen phosphate (ADP)
See also
Born-Infeld action
Filament propagation
Category:Nonlinear optical materials
Notes
^ Scientific American, December 1985, "Phase Conjugation," by Vladimir Shkunov and Boris Zel'dovich.
^ Scientific American, January 1986, "Applications of Optical Phase Conjugation," by David M. Pepper.
^ Scientific American, October 1990, "The Photorefractive Effect," by David M. Pepper, Jack Feinberg, and Nicolai V. Kukhtarev.
References
Robert W. Boyd, Nonlinear optics, Second edition, Academic press, (2003).
Y.R.Shen, The Principles of Nonlinear Optics, Wiley, (1984).
External links
Encyclopedia of laser physics and technology, with content on nonlinear optics, by Rdiger Paschotta
An Intuitive Explanation of Phase Conjugation
AdvR - NLO Frequency Conversion in KTP Waveguides
Categories: Nonlinear opticsHidden categories: Articles lacking sources from December 2008 | All articles lacking sources
Fireplace fireback
China Product
Functions of the fireback
The cast iron firebacks work on the same principle as heating radiators. The metal is heated (by hot water in the case of radiators and by the fire in the case of firebacks) and then that heat is radiated into the room. The thick iron keeps the heat that would else be lost and gives back this heat to the room. A fireback thus may increase the efficiency of the fire with as much as 50%. The thicker the fireback, the longer and softer this radiative effect.
A wood fire is of course never the most efficient use of heating. Yet, if you prefer the atmosphere of a open wood fire, the fireback helps to improve its efficiency. folding shop crane
Another important function of the fireback is the protection of the backside of the fireplace against burst and other damages. telescopic boom crane
Moreover, the old firebacks are often beautiful pieces of art and are therefore used for decorative purposes at the wall, or above the stove. honda pressure washer
Fireback in the house of Jeanne d'Arc Domrmy
History of firebacks
The oldest firebacks date back from the 15th century, the early days of casting iron. Originally, firebacks were luxury items to be used exclusively by the royalty, aristocracy and the church.
Thus the early firebacks show the weapons and shields of royalty and aristocracy and many religious themes. A landlord would as a rule employ his coat-of-arms alike in his own rooms as well as in the kitchens of his peasant-tenants. Thus these coat of arms are still widely available in original versions, as cast iron doesn wear much.
Later the firebacks received more decorative designs about classical stories, nature and rural live.
Literature
Carpentier, H.: Plaques de chemines 1925. (The best study ever of the themes of firebacks.)
Aitchison,L,: History of metals McDonald & Evans, London, 1960
Kelly,A.: The book of English fireplaces Country Life Books, Feltham, 1968
External links
Wikimedia Commons has media related to: Firebacks
Examples of antique firebacks and their symbolic meaning
Categories: Fireplaces
Tourism in Malaysia
China Product
Destinations and Attractions
Cities
Kuala Lumpur - the de jure capital of Malaysia. bow making ribbon
Petronas Twin Towers - World's tallest twin towers and third and fourth tallest singular towers, standing adjacent to one of the busiest shopping malls in Kuala Lumpur, Suria KLCC. organza pouches
Golden Triangle (Bukit Bintang and Imbi) - Kuala Lumpur's busiest commercial district containing five-star hotels, restaurants to high-end shopping malls. curling ribbon
George Town - the political capital of Penang. George Town is one of two cultural World Heritage Sites in Malaysia.
Gurney Drive - a popular seafront promenade, filled with condominiums and hotels. It is one of the busiest streets in Penang.
Ipoh - capital of Perak, famous for its Chinese food, tin mines and limestone mountains and caves.
Alor Star - capital of Kedah, the state of the Paddy fields.
Johor Bahru - capital of Johor, and gateway to Singapore.
Kangar - capital of Perlis, and gateway to Thailand.
Kota Kinabalu - capital of Sabah.
Kota Bahru - capital of Kelantan.
Kuala Terengganu - capital of Terengganu, famous for the penyu (turtles) and beaches.
Kuantan - capital of Pahang, noted for its many beaches.
Kuching - capital of Sarawak, the Cat City of Malaysia.
Melaka - a historical city in Malaysia. This is the other cultural World Heritage Site in Malaysia.
Miri - the resort city of Sarawak is the gateway to the UNESCO World Heritage Site of the Mulu caves and numerous magnificent tourism attractions.
Seremban - the capital of Negeri Sembilan, and the nearest cities to Port Dickson.
Putrajaya - the administrative centre of Malaysia, known for its lavish buildings, bridges and man-made lakes.
Petaling Jaya - a satellite city located in the state of Selangor, and is in the proximity of Kuala Lumpur. It has the most commercial complexes in Malaysia.
Beside the main cities, there other town and places in Malaysia offer some special tourist attraction. Such as in Taiping, Perak for their landscape and local attraction. Teluk Intan for their Leaning tower. Genting Highlands, Cameron Highlands and Bukit Tinggi in Pahang for a cool climate. Muar in Johor is famous for its food. Miri is the official tourism-city and resort city of Sarawak and Sibu in Sarawak is famous for its landscape and parks.
Islands and Beaches
Malaysia has several tropical islands, some of which have been voted the most beautiful in the world. Some of the islands in Malaysia are:
Labuan
Langkawi
Pangkor
Penang Island, the western half of Penang, which is heavily industrialised
Redang Island
Tenggol Island
Tunku Abdul Rahman National Park
Perhentian Islands
Kapas Island
Lang Tengah Island
Rantau Abang Beach
Mabul
Sipadan
National parks and nature reserves
Bako National Park, Sarawak - famed for its wildlife, especially bearded pigs and proboscis monkeys
Batang Ai National Park, Sarawak
Endau Rompin National Park, Johor
Gunung Gading National Park, Sarawak
Gunung Mulu National Park, Sarawak
Kinabalu National Park, Sabah - home of 4100 metre peak Mount Kinabalu.
Kubah National Park, Sarawak
Taman Negara National Park - the self-proclaimed World's Oldest Rainforest, spanning Kelantan, Pahang and Terengganu
References
^ "Malaysia escapes, but not unscathed". Asia Times. January 4, 2005. http://www.atimes.com/atimes/Southeast_Asia/GA04Ae05.html. Retrieved 2008-01-28.
External links
Malaysia travel guide from Wikitravel
Tourism Malaysia
Pahang Tourism Official Website
Second Home Malaysia: The Ultimate Guide to Malaysia Property
Malaysia Information
Travel Pahang & Surround Malaysia
v d e
Tourism in Asia
Sovereign
states
Afghanistan Armenia1 Azerbaijan1 Bahrain Bangladesh Bhutan Brunei Burma2 Cambodia People's Republic of China Cyprus1 East Timor3 Egypt4 Georgia4 India Indonesia Iran Iraq Israel Japan Jordan Kazakhstan4 North Korea South Korea Kuwait Kyrgyzstan Laos Lebanon Malaysia Maldives Mongolia Nepal Oman Pakistan Philippines Qatar Russia4 Saudi Arabia Singapore Sri Lanka Syria Tajikistan Republic of China5 Thailand Turkey4 Turkmenistan United Arab Emirates Uzbekistan Vietnam Yemen
States with limited
recognition
Abkhazia1 Nagorno-Karabakh Northern Cyprus Palestine South Ossetia1
Dependencies,
autonomies,
other territories
Aceh Adjara1 Akrotiri and Dhekelia Altai British Indian Ocean Territory Buryatia Christmas Island Cocos (Keeling) Islands Guangxi Hong Kong Inner Mongolia Iraqi Kurdistan Khakassia Macau Nakhchivan Ningxia Papua Sakha Republic Tibet Tuva West Papua Xinjiang
1 Sometimes included in Europe, depending on the border definitions. 2 Officially known as Myanmar. 3 Sometimes included in Oceania, and also known as Timor-Leste. 4 Transcontinental country. 5 Commonly known as Taiwan.
v d e
Tourism in Southeast Asia
Brunei Burma Cambodia East Timor Indonesia Laos Malaysia Philippines Singapore Thailand Vietnam
Categories: Tourism in Malaysia
Regulated Metal Deposition
China Product
Development
Miller Electric Mfg. Co. developed RMD technology in 2004 to address issues related to welding thin metal subject to burn-through, welding heat-sensitive alloys such as stainless steel, overcoming less-than-ideal fit-up (gaps) and welding root passes on pipe.
Compared to conventional short circuit GMAW, the RMD modified short circuit transfer process promotes smoother metal transfer, prevents excess puddle agitation and lowers heat input. When specified correctly, RMD Process can accomplish the following: disinfectant cleaner
In pipe welding applications, the RMD Process provides the following benefits: ice blasting
Reduce training time. The SMAW and GTAW processes, require a higher degree of hand-eye coordination to master. compared to RMD. sand blaster
Provide welding travel speeds of 6 to 12 inches per minute in fixed position pipe welding applications
Potential to eliminate the hot pass.
Potential to eliminate the need for backing gas for some of the 300 series stainless steel grades and chrome-moly steels.
It also provides these additional benefits on plate and pipe applications.
Minimize clean-up time, as the process creates no slag and little or no spatter.
Create the ability to bridge wide gaps and compensate for less-than-optimal fit-up.
Enable using the same wire and shielding gas for subsequent passes with other GMAW processes.
Equipment
Software
The RMD Process is software-driven. Miller factory-installs the software on its welding systems designed specifically for pipe welding; pipe-specific software is designated RMD-Pro. On welding systems designed for semi-automatic multi-MIG welding and automated/robotic welding multi-MIG welding, the optional RMD software can be factory installed at the time of product purchase, or users can upgrade at a later date.
Hardware
RMD is designed to operate with inverter-based welding systems, currently designed as the PipePro 450 RFC Welding System, PipeWorx Welding System, Axcess series and Auto-Axcess series. These systems include an inverter-based welding power source, wire feed control, and MIG gun/torch.
Electrode and shielding gas
The RMD Process uses standard solid wire electrodes for GMAW welding (AWS ERXXS-X) from 0.035 in. to 0.045 in. or 0.9 mm to 1.2 mm respectively. Acceptable shielding gases include most of those commonly used for conventional GMAW processes, e.g. 100% CO2, 90% argon/10% CO2 (C10), and 75% argon/25% CO2 (C25) for carbon steels and 98% argon/2% O2, 98% argon/2% CO2, and Tri H for stainless steels. Other gas variations can also be used and others are possible.
As long as the electrode and shielding gas support the process, some systems with RMD software can switch on-the-fly between RMD and any other process within the system, such as standard short circuit GMAW, spray transfer GMAW, conventional pulsed spray transfer GMAW Accu-Pulse pulsed transfer GMAW or Pro-Pulse pulsed transfer GMAW.
Operation
The RMD Process provides the benefits of advanced welding processes without a complex operator interface and extensive set-up. To begin welding with the RMD Process, operators use the system controls to select (from a pre-programmed menu) the material type, wire diameter and gas combination. The system then selects the optimum welding parameters from its library of application programs, available in the product. After that, operator sets the desired wire feed speed (WFS) to match the application and begins welding. The system automatically maintains all other variables as operators increase WFS (to weld thicker sections and/or increase travel speeds) or decrease WFS (to weld thinner sections or decrease travel speeds).
Welding with the RMD Process requires similar techniques to short circuit GMAW, but with slight modifications specific to the process (learn more).
Metal transfer process
Understanding short circuit GMAW
Standard short circuit transfer GMAW is preferred for thinner metals, as it is designed to operate at lower heat levels, most commonly 60 to 200 amperes and 16 to 22 volts. However, it has limitations. To understand RMD benefits, it is necessary to understand standard short circuit GMAW.
In standard short circuit transfer, the welding wire (electrode) initially contacts the work piece, creating a short reducing the voltage to a low value. At that point, the welding power source reacts to the short, attempting to maintain the preset voltage value by rapidly adding current to the wire to clear the short. As the wire heats from resistance to the high current flow, it forms an electromagnetic field at the end. The electrical force from this field then causes the molten bridge to constrict and subsequently clears the short. An arc is then reestablished, forming a ball at the end of the wire, for the next short-circuit. This process happens repetitively at a rate of about 90 to 150 times per second.
Observation of short circuit events using slow motion video emphasizes that the standard short circuit process can be viewed as a chaotic, unpredictable event that creates spatter and affects the next short circuit. Further, the uncontrolled rush of current adds more heat than necessary. Excess heat increases the likelihood of warping, may alter the metallurgical/mechanical properties of heat-sensitive metals and may produce burn-through in situations where the metal cannot support much heat, such as the edge of a thin plate or beveled pipe. The combination of current spikes and spatter may also lead to lack of confidence in fusion and/or consistent penetration.
Controlled RMD process transfer
The RMD transfer operates similarly to the short circuit transfer, but with some important differences. The RMD software program, working with an inverter-based welding system and closed-loop feedback, closely monitors and controls the electrode current at speeds up to 50 microseconds (50 millionths of a second). By closely monitoring the change in energy and understanding exactly how much is required for a specific wire diameter, speed and gas combination, the welding system can predict future arc conditions and control the metal transfer accordingly. It then applies a precisely controlled waveform at critical points in the short circuit cycle. With RMD technology, the welding system anticipates and controls the short circuit, then reduces available welding current to create consistent metal transfer. Precisely controlled metal transfer provides uniform droplet deposition, making it easier for the welder to control the puddle. High-speed video proves that stable short circuits create only small ripples in the weld puddle, which in turn allows consistent tie-in to the sidewall. As a result of a stable and more controllable weld puddle, apprentice operators can quickly and easily learn to create uniform, high quality welds.
Pipe welding
The RMD modified short circuit process provides several benefits for pipe welding:
1. Smooth metal transfer compensates for a high-low misalignment between pipe sections. The process easily bridges gaps of up to 3/16 inch.
2. Smooth metal transfer creates more consistent root reinforcement on the inside of the pipe.
3. The shielding gas coming out of the gun remains relatively undisturbed by the controlled transfer. As a result, enough shielding gas gets pushed through the root opening to prevent oxidation on the backside of the weld. Some fabricators have qualified procedures to weld some of the 300 series stainless steels and chrome-moly steels without a backing gas, improving productivity (large diameter pipes take a long time to purge, and the gas is costly).
4. The RMD Process maintains a consistent arc length regardless of electrode stick-out. It compensates for operators that have problems holding a constant stick-out, and it enables a better view of the weld puddle (as welders weld from the 4- to 6-olock position, they tend to increase their wire stick-out. With older technology, a long stick-out skews welding parameters and often compromises quality).
5. The RMD process creates a root pass weld with a 1/8 to 3/16 in throat. In many instances, the amount of root pass metal deposited will be sufficient to support the heat input requirements of the first pulsed GMAW or FCAW fill pass. Fabricators can eliminate the GTAW hot pass.
The same electrode and shielding gas used for the RMD process can also be used for the fill and cap passes using a next-generation pulsed GMAW process, called Pro-Pulse. This process improves performance and operator acceptance compared to traditional pulsed welding, and it improves both travel speeds and deposition rates while lowering overall heat input.
References
"Blasting the Bottleneck Blues." Practical Welding Today. 8 May 2007 <http://www.thefabricator.com/ArcWelding/ArcWelding_Article.cfm?ID=1628>
"Pipe Welding Video Available for Download." TheFabricator.com. 12 April 2008 <http://www.thefabricator.com/TubePipeFabrication/TubePipeFabrication_Products.cfm?ProductsID=993>
"Pipe Welding Technique Videos Now Available at MillerWelds.com." Miller Electric Mfg. Co. 23 Jun 2008 <http://www.carmenelectrode.com/pipe-welding-technique-videos-now-available-at-millerweldscom/>
External links
A case study
RMD Stainless Tech Story
Process overview
Categories: Arc weldingHidden categories: Articles with topics of unclear notability from January 2010 | All articles with topics of unclear notability | Articles that need to be wikified from January 2010 | All articles that need to be wikified
Bucket
China Product
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009) red wine stains
A plastic yellow bucket. walnut laminate flooring
Look up bucket in Wiktionary, the free dictionary. vinyl plank flooring
Wikimedia Commons has media related to: Buckets
A bucket, also called a pail, is a watertight, vertical cylinder or truncated cone, with an open top and a flat bottom, usually attached to a semicircular carrying handle called the bail. Their main purpose is the carrying of water, but they may also have other purposes. Elaborate ceremonial or ritual buckets in bronze, ivory or other materials are found in several ancient or medieval cultures and are known by the Latin for bucket, situla. Other buckets include those attached to Loader (equipment) and Telehandler for agricultural and earthmoving purposes. They can also be used to transport items other than water such as sand, rocks, and fish.
Roman bronze situla from Germany, 2nd-3rd century
A wooden bucket
German 19th century leather fire-buckets. With wood, leather was the most common material for buckets before modern times
A man carrying two buckets
A young lady carrying a bucket. By the German artist Heinrich Zille.
A mop bucket with a wringer.
An excavator bucket.
A helicopter bucket.
Plastic buckets on a beach, with two shovels
See also
Bobrinski Bucket
Mop
Categories: ContainersHidden categories: Articles lacking sources from December 2009 | All articles lacking sources
