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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Trumpų impulsų kokybės moduliacijos išilgai diodais kaupinami kietojo kūno minilazeriai: generavimas, charakterizavimas ir panaudojimas / Short pulse Q-switched longitudinally diode pumped solid state minilasers: generation, characterization and application

Slavinskis, Nerijus 30 June 2011 (has links)
Disertacija skirta diodais kaupinamų kietojo kūno lazerių su aktyviąja ir pasyviąja kokybės moduliacija generacijos dinamikos detalesnei skaitmeninei analizei, lazerio impulsų laikinių ir erdvinių parametrų charakterizavimui ir sukurtų minilazerių panaudojimo galimybių demonstracijai. Generacijos dinamikos detalesniai skaitmeniniai analizei, darbe pristatomas sukurtas bėgančiųjų bangų modelis, kuriame atsižvelgiama ne tik į daugelį procesų vykstančių lazerio aktyviajame elemente, bet ir į rezonatoriaus konfigūraciją bei kaupinimo šaltino parametrus. Pateikiami skaitinio modeliavimo rezultatai demonstruojantys šio modelio privalumus lyginant su dažniausiai naudojamu taškiniu lazerio modeliu. Naudojant taškinį lazerio modelį yra nagrinėjama generuojamų impulsų laikinio tirtėjimo problema pasyvios kokybės moduliacijos lazeriuose ir pasiūlyti mažinimo būdai naudojant skirtingus kaupinimo būdus. Darbe taip pat pateiktas naujas, antraisiais momentais pagrįstas, pluošto charakterizavimo judančiu peiliu metodas. Nagrinėjamos lazerių impulsų spūdos galimybės tetrachlorido CCL4 skystyje ir pademonstruota, kad naudojant užkrato signalą galima gauti trumpesnius (< 60 ps) ir stabilesnius optinius impulsus. Darbe pademonstruotos sukurtų minilazerių pritaikymo galimybės: aprašomas netiesinio lūžio rodiklio kvarciniame stikle matavimas Z-skenavimo metodu ir gautų duomenų apdorojimo procedūra įskaitant naudojamų impulsų erdvinę ir laikinę formą; aprašomi eksperimentai, kuriuose sukurti... [toliau žr. visą tekstą] / The dissertation is dedicated to the detailed numerical modelling of generation dynamics of actively and/or passively Q-switched diode laser longitudinally pumped solid-state lasers, characterization of spatial and temporal laser properties and for the demonstration of application possibility of created minilasers. A detailed theoretical model for the description of generation dynamics using travelling wave approach is presented. In this model more parameters of active laser medium, pump sources and resonator architecture are taken into account. In this thesis the results which show the principal difference between results obtained using the laser travelling wave model and point laser model are presented. Using point laser model the problems of generated pulse timing jitter in passively Q-switched lasers are described and its lowering possibilities using different pumping methods are suggested. In this thesis new, based by the second order moment, laser beam characterisation by knife-edge method is presented. Also laser pulse compression possibilities in tetrachloride CCL4 medium are described. It is showed that using seed signal it is possible to obtain shorter (< 60 ps) and more stable optical pulses. In this thesis application possibilities of created minilasers are presented: the experimental results of the Z-scan measurements obtained using pulses with different pulse shapes for fused silica are presented; also experiments, in which, created minilasers for paper cleaning... [to full text]
22

Estudo do comportamento físico, químico e reológico de ligante asfáltico modificado com polímero e materiais advindos de plantas amazônicas para aplicação em revestimento asfáltico

Cunha, Tayana Mara Freitas da 14 February 2011 (has links)
Made available in DSpace on 2015-04-11T13:47:50Z (GMT). No. of bitstreams: 1 TAYANA_CUNHA.pdf: 3246935 bytes, checksum: 4bfd4e26cc31d0040eded3e0c0d04580 (MD5) Previous issue date: 2011-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The study in question has researched the chemical and rheological properties of pure asphalt binder in Manaus (CAP 50/70-REMAN), and when modified with agents: synthetic polymer - a styrene-butadiene copolymer (SBS), natural fiber of fruits rind of Couepia edulis (Prance) (FCC) and antioxidant additive - fat Virola surinamensis - ucuúba (GU), aiming to bring benefits to the asphalt used in the region, as from the oxidative stress and heat, as well as a better performance of asphalt mixtures used in the process champion. Were determinate the properties of degradation and stabilization by thermal analysis - Termogravimetira (TG) and Differential Scanning Calorimetry (DSC), rheology, through Rheometer Dynamic Shear (Shear Rheometer Dynamical - DSR) under the parameters established in the specifications SUPERPAVE the aging process by thermoxidized (RTFOT) beyond the traditional characterization advocated by the National Petroleum Agency - ANP. The addition of modifying agents affected the physical, chemical and rheological properties, the main results: reduction in penetration rate, increase in softening point, good thermal stability and miscibility with the CAP, a significant increase in G* at low frequencies and decrease in tan δ, and the elevation of viscosity for the modified binders, but less pronounced by the presence of additive (GU). / comercializado em Manaus (CAP 50/70-REMAN), e quando modificado com os agentes: polímero sintético - copolímero de estireno e butadieno (SBS), fibra natural oriunda da casca da castanha de cutia (FCC) - Couepia edulis (Prance) e com aditivo antioxidante - gordura de Virola surinamensis ucuúba (GU), visando trazer benefícios ao asfalto utilizado na região, quanto ao efeito oxidativo e térmico, bem como quanto a um melhor desempenho das misturas asfálticas empregadas nas vias manauaras. Foram determinadas as propriedades de degradação e estabilização, pela análise térmica Termogravimetira (TG) e Calorimetria Exploratória Diferencial (DSC), o comportamento reológico, por meio do Reômetro de Cisalhamento dinâmico (Dynamical Shear Rheometer - DSR) segundo os parâmetros estabelecidos nas especificações SUPERPAVE, o envelhecimento pelo processo termoxidativo (RTFOT) além da caracterização tradicional preconizada pela Agência Nacional de Petróleo ANP. A adição de agentes modificadores afetou as propriedades físicas, químicas e reológicas, tendo como principais resultados: redução nos índice de penetração, aumento no ponto de amolecimento, boa estabilidade térmica e miscibilidade com o CAP, aumento significativo no G* em baixas freqüências e diminuição na tan δ, além da elevação da viscosidade para os ligantes modificados, porém menos pronunciada pela presença de aditivo (GU).
23

Faculty Senate Minutes December 5, 2011

University of Arizona Faculty Senate 05 December 2011 (has links)
This item contains the agenda, minutes, and attachments for the Faculty Senate meeting on this date. There may be additional materials from the meeting available at the Faculty Center.
24

Shaken Baby Syndrome Prevention: Implementation of an Individualized, Patient-Centered Education Program

Schutt, Alexandra Dimitra, Schutt, Alexandra Dimitra January 2016 (has links)
Background: Child maltreatment is a serious health concern in the United States (U.S.) affecting as many as one in four children throughout their lifetime (Finkelhor, Turner, Ormond, & Hamby, 2013). In 2013, a reported 678, 932 victims of child maltreatment were reported to Child Protective Services (CPS), and of those cases 1,520 were fatal (CDC, 2015a). Out of all the various types of child maltreatment, Shaken Baby Syndrome (SBS) is the leading cause of child abuse deaths in the U.S. (CDC, n.d.). While current research has focused on validating the effectiveness of educational interventions, very few studies have analyzed the efficacy of individualized, patient-centered action plans. Such data would be beneficial to assess the usefulness of action plans in preparing caregivers for coping with an inconsolable infant at home. Purpose: To enhance caregiver knowledge about SBS and to provide parents with the skills and resources necessary to cope effectively and efficiently at home when unable to console their infant. Methods: This study utilized a quasi-experimental pre-test/post-test design. Participants were recruited from the Franciscan Women’s Health Associates located at St. Joseph Medical Center in Tacoma, Washington and were members of the Centering prenatal groups. The entirety of the study was completed during these groups including the pre-test, intervention, action plan, and post-test. Data was analyzed through the utilization of descriptive statistics as well as a paired t test. Results: Overall, results revealed that participant (n=26) knowledge significantly improved after the educational intervention (p=0.000) with a mean score of 87.56% on the pre-test and a mean score of 95.38% on the post-test. In addition, a majority of participants (57.5%) found both the action plan and the education to be extremely useful. Discussion: The results of this study were consistent with current evidence indicating that education on SBS, the dangers of shaking, and healthy coping mechanisms significantly impacts caregiver knowledge. In addition, a majority of participants viewed the action plans favorably identifying that they would be beneficial if they felt frustrated. Future research is warranted to gather more information on the long-term outcomes of educational interventions as well as individualized action plans.
25

Evaluación del comportamiento mecánico de mezclas SMA y Superpave empleando asfalto modificado con Polímero SBS (Estireno-Butadieno-Estireno)

Fernández Villalba, Omar A., Cáceres Salinas, Edgardo G. January 2007 (has links)
El objetivo principal de este trabajo fue evaluar el comportamiento mecánico de mezclas asfálticas del tipo Superpave y SMA (Stone Mastic Asphalt) mediante un análisis comparativo del desempeño del asfalto convencional y del asfalto modificado con SBS (estireno–butadieno-estireno). Determinando módulos dinámicos edométricos de mezclas asfálticas a diferentes temperaturas de ensayo.
26

The side-by-side model of DNA: logic in a scientific invention

Stokes, Terence Douglas January 1983 (has links)
Watson and Crick’s double-helical model of DNA is considered to be one of the great discoveries in biology. However, in 1976, two groups of scientists, one in New Zealand, the other in India, independently published essentially the same radical alternative to the double helix. The alternative, Side-By-Side (SBS) or ‘warped zipper’ conformation for DNA is not helical. Rather than intertwine, as do Watson and Crick’s helices, its two exoskeletal strands are topologically independent. Thus, unlike the double helix, they may separated during replication without unwinding. This dissertation presents, but does not arbitrate among scientific arguments. Its concerns are meta-scientific; in particular, why and how the individuals who invented the & ‘warped zipper’ came to do so. Against Popper and most recent philosophers of science, it is taken to be “the business of epistemology to produce what has been called a ‘rational reconstruction’ of the steps that have led the scientist to a discovery [Popper (1972), p.31, emphasis in the original].” On the received view, the invention of the ‘warped zipper’ must be irrational or, at best, non-rational thereby excluding from philosophical investigation. I establish that this philosophical dogma is not true a priori, as is usually supposed, and, in the case of the SBS structure of DNA, false a posteriori. The motivation for, and development of the SBS structure for DNA reveals a process best characterized as significantly, though not entirely, rational.
27

The side-by-side model of DNA: logic in a scientific invention

Stokes, Terence Douglas January 1983 (has links)
Watson and Crick’s double-helical model of DNA is considered to be one of the great discoveries in biology. However, in 1976, two groups of scientists, one in New Zealand, the other in India, independently published essentially the same radical alternative to the double helix. The alternative, Side-By-Side (SBS) or ‘warped zipper’ conformation for DNA is not helical. Rather than intertwine, as do Watson and Crick’s helices, its two exoskeletal strands are topologically independent. Thus, unlike the double helix, they may separated during replication without unwinding. This dissertation presents, but does not arbitrate among scientific arguments. Its concerns are meta-scientific; in particular, why and how the individuals who invented the & ‘warped zipper’ came to do so. Against Popper and most recent philosophers of science, it is taken to be “the business of epistemology to produce what has been called a ‘rational reconstruction’ of the steps that have led the scientist to a discovery [Popper (1972), p.31, emphasis in the original].” On the received view, the invention of the ‘warped zipper’ must be irrational or, at best, non-rational thereby excluding from philosophical investigation. I establish that this philosophical dogma is not true a priori, as is usually supposed, and, in the case of the SBS structure of DNA, false a posteriori. The motivation for, and development of the SBS structure for DNA reveals a process best characterized as significantly, though not entirely, rational.
28

Analys av Nedbrytningsprodukter av Polymerer för Bitumenändamål

Lindström, Björn January 2007 (has links)
<p>This project was aimed to study the degradation of polystyrene-butadiene-styrene block copolymer (SBS). SBS is used to modify bitumen, the binder in asphalt. From earlier studies it is known that SBS degrades in bitumen, but the degradation products have not been identified. To be able to determine the long term effects of SBS in the environment, degradation products need to be identified. Polystyrene forms rigid blocks with polybutadiene as a rubbery matrix between the ridgid blocks. When blended in bitumen, the polystyrene blocks are crosslinked to form a three dimensional network. SBS is an elastomer and has the ability to regain its shape after being a subject of mechanical force. According to the pre references the polymers had to be degraded in similar ways as they would in bitumen. Since bitumen is a very complex matrix with high boiling point and viscosity, there would be difficulties separating polymers from the bitumen. We made an assumption that it would be plausible for the degradation products formed in bitumen to form even with no bitumen present. Four different SBS polymers were used. One of the polymers was branched. Another had a high content of 1-2 polybutadiene. The third was a diblock copolymer (SB) with low styrene content compared to the others. The last was a linear SBS. The polymers were degraded in pieces of apparatus used for study ageing characteristics of bitumen as well as they were aged by refluxing in hexane. The degradation products were extracted by Solid Phase Extraction (SPE) and identified by GC-MS. Due to instrumental limits there were not many degradation products identified. The main products detected included saturated hydrocarbons in the range of 16-31 carbon atoms as well as squalene.</p> / <p>I det här projektet studerades nedbrytning av styren-butadien-styren block kopolymerer (SBS). SBS används för att modifiera bitumen vars användningsområde är som bindemedel i asfalt. Tidigare studier har visat att SBS bryts ned i bitumen, men nedbrytningsprodukterna har inte identfierats. För att kunna avgöra vad SBS har för långsiktiga effekter på miljön måste nedbrytnignsprodukterna identifieras. I SBS bildar polystyren styva block medan polybutadien fungerar som flexibla bryggor mellan polystyrenblocken. När SBS blandas med bitumen korslänkas polystyrenblocken så att ett tredimensionellt nätverk bildas. Eftersom SBS är en elastomer har den förmågan att återfå sin ursprungliga form efter att ha blivit utsatt för mekanisk stress. Enligt de givna förutsättningarna för studien skulle polymererna brytas ned på samma sätt som om de skulle ha varit lösta i bitumen. Eftersom bitumen är en komplex matris med hög kokpunkt och viskositet skulle det varit svårt att separera polymererna och deras nedbrytningsprodukter från bitumenet. Vi gjorde ett antagande om att det förmodligen bildas samma nedbrytningsprodukter som om bitumen varit närvarande även om nedbrytningen sker utan bitumen närvarande. Fyra olika SBS polymerer användes. En av polymererna var grenad. En annan hade en stor andel 1,2-polybutadien. Den tredje var en diblock kopolymer (SB) med lågt styren innehåll jämfört med de andra. Den sista polymeren var linjär. Polymererna åldrades i apparatur framtagen för att studera åldring av bitumen. Polymererna åldrades även genom att återloppskokas i hexan. Nedbrytningsprodukterna extraherades via fastfasextraktion (SPE) och identifierades med GC-MS. Genom instrumentella begränsningar kunde bara ett fåtal nedbrytningsprodukter identifieras. Bland de produkter som identifierades fanns alkaner och alkener med mellan 16 och 31 kolatomer, men även skvalen identifierades som nedbrytningsprodukt. Lågmolekylära ämnen kan ha ventilerats bort för att vi inte hade tillgång till apparatur för adsorbtion av flyktiga ämnen för injektion i GC-MS. </p>
29

Personality, Stress, and Indoor Environmental Symptomatology

Runeson, Roma January 2005 (has links)
<p>The sick building syndrome (SBS) comprises eye, nose, skin, and throat symptoms, headache and fatigue. Gender, personality aspects, and psychosocial factors at work have lately been at focus in health research. The main aim of this thesis was to investigate the relationships between SBS and personal factors, personality traits, and psychosocial work stress. Two different populations were studied: a cohort of 195 subjects working in suspected “sick buildings” followed 1988-1999, and a random sample of 695 subjects from the Swedish population, 20-65 y. Two personality scales were used; the Karolinska Scales of Personality (KSP) and the Sense of Coherence (SOC). Two stress questionnaires were used: the 3-dimensional demands-control-support model (DCS) and the Assessment of Perceived Psychosocial Work Environment (PPWE). SBS and personal factors were assessed by a postal symptoms questionnaire and a symptom score (SC) was calculated. Personality was assessed by means of two verbal personality scales, the KSP and the SOC. Females in problem buildings had more SBS than men, and females had a lower SOC and more anxiety and aggressivity in the KSP. Females and males in the general working population reported differences in psychosocial work environment. Moreover, the associations between personality traits and SBS, and between DCS and SBS, differed between males and females. Over all, the investigated occupants of suspected sick-buildings were within the normal range for both KSP and SOC norms. However, those with symptoms showed prominent personality vulnerability, especially in anxiety, aggressivity, and lower SOC, compared to those that were not reporting symptoms. Female gender, low age, asthma, and a history of atopy were related to SBS in the general working population. A combination of low social support and either passive, strained, or active work situation, as well as a combination of high social support and active work situation, were associated with SBS. In conclusion, measurements of personality and psychosocial work environment could be of value in future studies on environmental syndromes. Moreover, the demans-control-support model can predict SBS, but in a more complex way than indicated by earlier research. </p>
30

Analys av Nedbrytningsprodukter av Polymerer för Bitumenändamål

Lindström, Björn January 2007 (has links)
This project was aimed to study the degradation of polystyrene-butadiene-styrene block copolymer (SBS). SBS is used to modify bitumen, the binder in asphalt. From earlier studies it is known that SBS degrades in bitumen, but the degradation products have not been identified. To be able to determine the long term effects of SBS in the environment, degradation products need to be identified. Polystyrene forms rigid blocks with polybutadiene as a rubbery matrix between the ridgid blocks. When blended in bitumen, the polystyrene blocks are crosslinked to form a three dimensional network. SBS is an elastomer and has the ability to regain its shape after being a subject of mechanical force. According to the pre references the polymers had to be degraded in similar ways as they would in bitumen. Since bitumen is a very complex matrix with high boiling point and viscosity, there would be difficulties separating polymers from the bitumen. We made an assumption that it would be plausible for the degradation products formed in bitumen to form even with no bitumen present. Four different SBS polymers were used. One of the polymers was branched. Another had a high content of 1-2 polybutadiene. The third was a diblock copolymer (SB) with low styrene content compared to the others. The last was a linear SBS. The polymers were degraded in pieces of apparatus used for study ageing characteristics of bitumen as well as they were aged by refluxing in hexane. The degradation products were extracted by Solid Phase Extraction (SPE) and identified by GC-MS. Due to instrumental limits there were not many degradation products identified. The main products detected included saturated hydrocarbons in the range of 16-31 carbon atoms as well as squalene. / I det här projektet studerades nedbrytning av styren-butadien-styren block kopolymerer (SBS). SBS används för att modifiera bitumen vars användningsområde är som bindemedel i asfalt. Tidigare studier har visat att SBS bryts ned i bitumen, men nedbrytningsprodukterna har inte identfierats. För att kunna avgöra vad SBS har för långsiktiga effekter på miljön måste nedbrytnignsprodukterna identifieras. I SBS bildar polystyren styva block medan polybutadien fungerar som flexibla bryggor mellan polystyrenblocken. När SBS blandas med bitumen korslänkas polystyrenblocken så att ett tredimensionellt nätverk bildas. Eftersom SBS är en elastomer har den förmågan att återfå sin ursprungliga form efter att ha blivit utsatt för mekanisk stress. Enligt de givna förutsättningarna för studien skulle polymererna brytas ned på samma sätt som om de skulle ha varit lösta i bitumen. Eftersom bitumen är en komplex matris med hög kokpunkt och viskositet skulle det varit svårt att separera polymererna och deras nedbrytningsprodukter från bitumenet. Vi gjorde ett antagande om att det förmodligen bildas samma nedbrytningsprodukter som om bitumen varit närvarande även om nedbrytningen sker utan bitumen närvarande. Fyra olika SBS polymerer användes. En av polymererna var grenad. En annan hade en stor andel 1,2-polybutadien. Den tredje var en diblock kopolymer (SB) med lågt styren innehåll jämfört med de andra. Den sista polymeren var linjär. Polymererna åldrades i apparatur framtagen för att studera åldring av bitumen. Polymererna åldrades även genom att återloppskokas i hexan. Nedbrytningsprodukterna extraherades via fastfasextraktion (SPE) och identifierades med GC-MS. Genom instrumentella begränsningar kunde bara ett fåtal nedbrytningsprodukter identifieras. Bland de produkter som identifierades fanns alkaner och alkener med mellan 16 och 31 kolatomer, men även skvalen identifierades som nedbrytningsprodukt. Lågmolekylära ämnen kan ha ventilerats bort för att vi inte hade tillgång till apparatur för adsorbtion av flyktiga ämnen för injektion i GC-MS.

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