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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.
121

Belöningssystem inom språkinlärning

Ringvold, Sebastian, Nordness, Anton January 2019 (has links)
Rewards can be used to navigate a person’s behaviour through stimulation. Knowledge about how humans experience and react to rewards has been of use in many areas, one such example is how retailers use point systems to retain customers. This paper aimed to investigate how users of language learning applications feel that they were motivated by their reward systems. To analyse this earlier research in motivational perspectives was used as well as a model of user technology acceptance. This was researched through a case study, for which a pre-study was done on five chosen applications to identify what rewards systems had been implemented in them. Two applications were picked because of the document analysis, which were then used by the test subjects as part of the study. Before they started using the applications, each test subject was interviewed to ascertain their levels of interest and language skills. They were then asked to use the applications however much they’d like over a two to three-week period. The result showed that all our subjects had noticed in one way or another. What they perceived as most motivating differed between all the subjects, but all of them were affected by at least some of the reward system we asked about. We found that all our subjects agreed that the reward systems compromising of streaks were the most motivating. Our subjects were split in what sort of streak they preferred. Some preferred the sort of streak you collect from using the application daily while others preferred the streak you gain when you answer right to several questions in a row. / Belöningar kan stimulera en person och styra dennes beteende. Kunskaper om hur människan reagerar på och upplever belöningar har använts i olika områden, till exempel återförsäljare som använder poängsystem för att hålla kvar sina kunder. Syftet med den här uppsatsen var att undersöka hur användare av språkinlärningsapplikationer upplever att belöningssystemen motiverade dem. Teorin som användes var tidigare forskning om olika motiverande perspektiv samt en modell över hur användare accepterar ny teknologi. Undersökningen var strukturerad som en fallstudie där det först utfördes en förstudie av utvalda applikationer för att identifiera de olika belöningssystemen som fanns i språkinlärningsapplikationerna. Genom förstudien bestämdes även de två språkinlärningsapplikationer försökspersonerna fick använda.  Försökspersonerna intervjuades kort för att skapa en profil om vilka de var och vilken tidigare erfarenhet de hade av språk och språkinlärningsapplikationer. Därefter fick de använda båda applikationerna under 2 till 3 veckor. Slutligen utfördes längre intervjuer med varje person för att ta reda på hur de hade upplevt belöningssystemen. Resultatet visade på att alla försökspersoner hade märkt av belöningssystemen på något sätt. Det skilde sig från person till person vad de ansåg var mest motiverande, men alla blev motiverade av någon av de belöningssystemen som det frågades om. Det som försökspersonerna var mest överens om var att Streaks (vilket är när systemet håller koll på när användaren utfört handlingar flera gånger i rad) var motiverande. Författarna kunde också se att vissa av försökspersoner upplevde att den formen av streak som innebar att försökspersonen använde språkinlärningsapplikationen flera dagar i rad var mer motiverande, medan andra ansåg att den formen av streak som innebar att försökspersonen fick flera rätt svar i rad i språkinlärningsapplikationen var mer motiverande.
122

The Effect of Superheat on Liquid Droplets in a Supersonic Freestream

Newman, Aaron W. 11 May 1999 (has links)
The effect of superheat on the disruption of liquid droplets in a compressible gas flow was investigated experimentally in a small-scale, supersonic wind tunnel. Aerodynamically generated ethanol droplets of an average diameter of 0.1 mm were injected via a normal sonic jet into a Mach 1.8 freestream. Both nonsuperheated and superheated droplets were injected with initial Weber numbers of approximately 700. The droplets and flow structure were photographed using the shadowgraph method. The relatively high momentum of the liquid droplets typically caused them to pass out of the sonic jet structure. Nonsuperheated droplets showed no signs of disrupting after traveling over 200 mm downstream from the injection point. Only droplets with injection temperatures above the predicted boiling point at tunnel freestream static pressure (48°C) showed signs of disruption, typically after they left the sonic jet structure (30 to 100 mm downstream of the injection point). Droplets in this range of temperatures appeared to begin to boil from the downstream side of the droplet, shedding a vapor cloud before disrupting completely in the chaotic mode. Droplets with temperatures above the boiling point at the exit plane of the sonic jet began to disrupt in the chaotic mode almost instantly (within 1 exit nozzle diameter).
123

The evolution of fuel nitrogen during the vaporization of heavy fuel oil droplet arrays

Hanson, Simon Peter January 1982 (has links)
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Simon Peter Hanson. / Sc.D.
124

Análise histológica, morfométrica, expressão de genes, proteínas e western blot na retina de ratos com glaucoma induzido e tratados com citrato de sildenafil tópico / Histological, morphometric analysis, expression of genes, proteins and western blot in the retina of glaucoma-induced rats and treated with sildenafil citrate

Zanoni, Diogo Sousa [UNESP] 11 December 2018 (has links)
Submitted by DIOGO SOUSA ZANONI (zanoni_19@hotmail.com) on 2019-01-31T11:46:22Z No. of bitstreams: 1 Defesa Doutorado - entrega Pós.pdf: 2160080 bytes, checksum: a016ec7f20ec85dc0433f4452821780e (MD5) / Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2019-01-31T19:07:54Z (GMT) No. of bitstreams: 1 zanoni_ds_dr_botfmvz.pdf: 2160080 bytes, checksum: a016ec7f20ec85dc0433f4452821780e (MD5) / Made available in DSpace on 2019-01-31T19:07:54Z (GMT). No. of bitstreams: 1 zanoni_ds_dr_botfmvz.pdf: 2160080 bytes, checksum: a016ec7f20ec85dc0433f4452821780e (MD5) Previous issue date: 2018-12-11 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O glaucoma é a principal causa global de cegueira irreversível e o número de pessoas com glaucoma em todo o mundo aumentará para 111,8 milhões em 2040, mesmo com os tratamentos vigentes. Deste modo, enseja uma necessidade de desenvolver terapias neuroprotetoras que possam ser usadas para reduzir os efeitos perniciosos do glaucoma, como a morte de células ganglionares da retina (CGR). Avanços na compreensão da fisiopatologia do glaucoma é um fator chave na compreensão da patogênese da neuropatia glaucomatosa. Neste contexto a isquemia retiniana desempenha um papel central em várias doenças da retina. A patogênese da isquemia retiniana envolve alterações temporais da morfologia e morfometria da retina assim como mudanças na expressão gênica e protéica. O Citrato de Sildenafila (SC) mostrou efeito protetor nos modelos de isquemia/reperfusão (I/R) com efeitos neuroprotetores. Contudo, a administração oral de CS, em humanos, encontra inúmeros efeitos colaterais, tais como redução da pressão arterial, dores de cabeça, rubor e congestão nasal são concomitantes, assim como pacientes com moderada a grave doença cardiovascular ou aqueles submetidos a terapia a base de nitrato apresentam riscos secundários aumentados para efeitos cardiovasculares adversos. Deste modo, propomos que a administração tópica de CS pode ser uma alternativa à via oral e também ser igualmente neuroprotetor no glaucoma e podem minimizar os riscos indesejados no uso sistêmico desse fármaco, além de oferecer uma nova abordagem para a intervenção terapêutica na patogênese da neuropatia glaucomatosa. Caso nossos resultados sejam positivos, em um estudo tão abrangente, pode levar a um ensaio clínico deste fármaco seguro e promissor em pacientes com glaucoma. / Glaucoma is the leading global cause of irreversible blindness and the number of people with glaucoma worldwide will increase to 111.8 million by 2040, even with current treatments. Thus, there is a need to develop neuroprotective therapies that can be used to reduce the deleterious effects of glaucoma, such as retinal ganglion cell death (RBC). Advances in understanding the pathophysiology of glaucoma are a key factor in understanding the pathogenesis of glaucomatous neuropathy. In this context, retinal ischemia plays a central role in various diseases of the retina. The pathogenesis of retinal ischemia involves temporal changes in retinal morphology and morphometry as well as changes in gene and protein expression. Sildenafil Citrate (SC) showed protective effect in the ischemia / reperfusion (I / R) models with neuroprotective effects. However, oral administration of CS in humans finds numerous side effects such as reduced blood pressure, headaches, flushing and nasal congestion are concomitant, as well as patients with moderate to severe cardiovascular disease or those undergoing nitrate therapy have increased secondary risks for adverse cardiovascular effects. Thus, we propose that the eye drops administration of CS may be an alternative to the oral route and also be equally neuroprotective in glaucoma and may minimize the undesirable risks in the systemic use of this drug, as well as offer a new approach for the therapeutic intervention in the pathogenesis of neuropathy glaucomatous. If our results are positive, in such a comprehensive study, it may lead to a clinical trial of this safe and promising drug in patients with glaucoma. / 142471\2015-1
125

Análise histológica, morfométrica, expressão de genes, proteínas e western blot na retina de ratos com glaucoma induzido e tratados com citrato de sildenafil / Histological, morphometric analysis, expression of genes, proteins and western blot in the retina of glaucoma-induced rats and treated with sildenafil citrate

Zanoni, Diogo Sousa [UNESP] 11 December 2018 (has links)
Submitted by DIOGO SOUSA ZANONI (zanoni_19@hotmail.com) on 2019-02-01T17:03:15Z No. of bitstreams: 1 Defesa Doutorado - entrega Pós.pdf: 2159159 bytes, checksum: c32db30aea42543516cc0f930e17164d (MD5) / Approved for entry into archive by Ana Lucia de Grava Kempinas (algkempinas@fca.unesp.br) on 2019-02-01T18:10:48Z (GMT) No. of bitstreams: 1 zanoni_ds_dr_botfmvz.pdf: 2159159 bytes, checksum: c32db30aea42543516cc0f930e17164d (MD5) / Made available in DSpace on 2019-02-01T18:10:48Z (GMT). No. of bitstreams: 1 zanoni_ds_dr_botfmvz.pdf: 2159159 bytes, checksum: c32db30aea42543516cc0f930e17164d (MD5) Previous issue date: 2018-12-11 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O glaucoma é a principal causa global de cegueira irreversível e o número de pessoas com glaucoma em todo o mundo aumentará para 111,8 milhões em 2040, mesmo com os tratamentos vigentes. Deste modo, enseja uma necessidade de desenvolver terapias neuroprotetoras que possam ser usadas para reduzir os efeitos perniciosos do glaucoma, como a morte de células ganglionares da retina (CGR). Avanços na compreensão da fisiopatologia do glaucoma é um fator chave na compreensão da patogênese da neuropatia glaucomatosa. Neste contexto a isquemia retiniana desempenha um papel central em várias doenças da retina. A patogênese da isquemia retiniana envolve alterações temporais da morfologia e morfometria da retina assim como mudanças na expressão gênica e protéica. O Citrato de Sildenafila (SC) mostrou efeito protetor nos modelos de isquemia/reperfusão (I/R) com efeitos neuroprotetores. Contudo, a administração oral de CS, em humanos, encontra inúmeros efeitos colaterais, tais como redução da pressão arterial, dores de cabeça, rubor e congestão nasal são concomitantes, / Glaucoma is the leading global cause of irreversible blindness and the number of people with glaucoma worldwide will increase to 111.8 million by 2040, even with current treatments. Thus, there is a need to develop neuroprotective therapies that can be used to reduce the deleterious effects of glaucoma, such as retinal ganglion cell death (RBC). Advances in understanding the pathophysiology of glaucoma are a key factor in understanding the pathogenesis of glaucomatous neuropathy. In this context, retinal ischemia plays a central role in various diseases of the retina. The pathogenesis of retinal ischemia involves temporal changes in retinal morphology and morphometry as well as changes in gene and protein expression. Sildenafil Citrate (SC) showed protective effect in the ischemia / reperfusion (I / R) models with neuroprotective effects. However, oral administration of CS in humans finds numerous side effects such as reduced blood pressure, headaches, flushing and nasal congestion are concomitant, as well as patients with moderate to severe cardiovascular disease or those undergoing nitrate therapy have increased secondary risks for adverse cardiovascular effects. Thus, we propose that the eye drops administration of CS may be an alternative to the oral route and also be equally neuroprotective in glaucoma and may minimize the undesirable risks in the systemic use of this drug, as well as offer a new approach for the therapeutic intervention in the pathogenesis of neuropathy glaucomatous. If our results are positive, in such a comprehensive study, it may lead to a clinical trial of this safe and promising drug in patients with glaucoma. / 142471\2015-1
126

The effect of solute dissolution kinetics on cloud droplet formation

Asa-Awuku, Akua Asabea 18 January 2006 (has links)
This study focuses on the importance of solute dissolution kinetics for cloud droplet formation. To comprehensively account for the kinetics, a numerical model of the process was developed. Simulations of cloud droplet growth were performed for solute diffusivity, droplet growth rates, dry particle and droplet diameters relevant for ambient conditions. Simulations suggest that high ambient supersaturations and a decrease in solute diffusivity are major contributors to significant decreases in effective solute surface concentrations. The numerical simulations were incorporated into Khler theory to assess the impact of dissolution kinetics on the droplet equilibrium vapor pressure. For CCN composed of partially soluble material, a significant increase was found in the equilibrium supersaturation of CCN.
127

Investigation of Nonwetting System Failure and System Integration

Nagy, Peter Takahiro 20 November 2006 (has links)
A droplet may be prevented from wetting a solid surface by the existence of a lubricating film of air, driven by theromcapillary convection, between liquid and solid surfaces. The noncontact nature and the load-carrying capability of a nonwetting droplet lead to potential engineering applications, e.g., low-friction bearings. The present research consists of two thrusts. The first is aimed at quantifying nonwetting-system failures (film and pinning) triggered by application of a mechanical load, gaining insights to failure mechanisms. Experimental results show that film failure occurs over a wide range of droplet volumes when the temperature difference between the droplet and the plate, the driving potential of the free-surface motion, is small. Interferometric observations reveal flow instability just prior to film failure, with the growth of a nonaxisymmetric disturbance on a free surface (m = 1). Pinning failure becomes more prevalent as the temperature difference is increased, stabilizing the film flow. As part of the present investigation, a system was devised, allowing an oscillating free-surface to be reconstructed from a series of interferograms. The dynamic responses of the free surface reveal mode coupling, with harmonics of the input frequency excited through nonlinearity. The second thrust of the research succeeded in levitating and translating a droplet using the mechanism of permanent nonwetting. In this scheme, the droplet is heated by a CO2 laser and is placed above a cooled glass surface in order to drive the lubricating film that supports the weight of the drop. Furthermore, the position of the droplet can be controlled by moving the heating location, which leads to an asymmetry of the flow fields, driving air from the cooler-end of the droplet and propelling it towards the heat source. These demonstrations suggest the techniques potential use as a liquid-delivery scheme in a Lab-On-a-Chip system. Modeling is carried out to estimate propulsive forces on the droplet and to explain oscillatory behavior observed when excessive heating is applied on the drop. The concept to sandwich a droplet between two plates, a necessary configuration for levitating smaller droplets (less than mm-scale), is also discussed.
128

Drop-on-demand inkjet drop formation of dilute polymer solutions

Yan, Xuejia 25 August 2010 (has links)
The research discussed in this dissertation was conducted to understand drop formation of inkjet printing with inks containing polymer. Solutions containing a water soluble polymer, poly ethylene oxide (PEO), with different molecular weights and polydispersities were used as inks. A flash photographic technique was used to visualize the whole process of DOD drop formation of dilute polymer solutions. The effects of driving signal, frequency and liquid properties on drop speed, drop size, breakup time and the formation of satellites were studied in detail. The addition of PEO increases the shear viscosity at all molecular weights, but the change is small for dilute solutions. However, the addition of a small amount of PEO can have a significant effect on the DOD drop formation process, increasing breakup time, decreasing primary drop speed and decreasing the number of satellites in some cases. The effects depend on both molecular weight and concentration. At lower molecular weights (14k and 35k g/mol), the effect of PEO was small when the drop formation process for the dilute solution was compared with that of a Newtonian liquid having similar shear viscosity, and the effect of PEO was small even at concentrations large enough that the solution does not fall in the dilute regime. As molecular weight is increased, the effects of PEO on DOD drop formation increase significantly, and the effects of concentration become important. These effects are explained by the fluid elasticity which increases with increasing in molecular weight and concentration. When the liquid jets out of the nozzle, the polymer chains are stretched, and thus depart from their ideal coiled state. As a result, an elastic stress develops in the liquid column and resists capillarity-driven pinch off from the nozzle and is responsible for the decrease in drop speed and longer breakup time. DOD drop formation data were shown to correlate closely with effective relaxation time, proposed by Tirtaatmadja based on Rouse-Zimm theory. When driving voltage amplitude is 44.2 V, two important parameters (breakup time and primary drop speed) in DOD drop formation for solutions containing monodispersed PEO and aqueous solutions containing mixtures of monodispersed PEO were closely predicted by correlation equations involving effective relaxation time . A mixture rule was developed to calculate the relaxation time for mixtures of monodispersed PEO. However, for polydispersed PEO, effective relaxation time was based on viscous molecular weight since the molecular weight distributions of the polydispersed PEO were unknown. When breakup time was plotted versus effective relaxation time for 1000k g/mol PEO, the data did not lie on the same line as that for the 100k and 300k g/mol PEO. This is believed to be due to the molecular weight distributions of the polydispersed PEO. When more than one species are present, viscous average molecular weight does not adequately account for the long chain species making up the polymer sample. DOD drop formation dynamics is highly affected by the actuating waveform, including the driving voltage, waveform shape, and frequency. The effects of parameters (jetting frequency, voltage amplitude and the shape of waveform) characterizing the signal were investigated. The open time and first drop problem were also studied. Research in this dissertation gives a better understanding of DOD drop formation process of polymer solutions, which may lead to improvement of inkjet printing quality for a variety of industry inks and polymer micro scale deposition and patterning in large areas.
129

Sublingual Immunotherapy

Ferrell, Melissa Leann January 2015 (has links)
One of the most common reasons people seek primary care and emergency care is to reduce the symptoms of allergies, such as hay fever. To meet this high demand, several recent FDA-approved methods for treating seasonal and perennial allergies have been developed, including sublingual immunotherapy tablets. Furthermore, no longer must a patient endure allergy shots; this can now be delivered sublingually. Although this method has been shown to have high safety and efficacy, very few clinicians actually utilize this form of therapy. The purpose of this paper is describe the use of sublingual immunotherapy among Nurse Practitioners (NPs) and discuss barriers that may prevent its use. Nurse Practitioners working in primary care settings were surveyed regarding their use of sublingual immunotherapy. Although many nurse practitioners treat patients with allergic disease, not one participant reported using sublingual immunotherapy. This discussion outlines some of the reasons NPs are not currently utilizing this method of allergy treatment and the findings are compared with the extant literature. This paper culminates in an evidence-based algorithm to outline best practices for utilizing sublingual immunotherapy to reduce allergy symptoms.
130

A THEORETICAL INVESTIGATION OF THE DYNAMICS OF LIQUID DROPS

Foote, G. Brant January 1971 (has links)
No description available.

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