29,655 research outputs found
AlGaN/GaN HEMT micro-sensor technology for gas sensing applications
No full text Wide bandgap gallium nitride material has highly favorable electronic properties for next generation power and high frequency electronic devices. A less widely studied application is highly miniaturized chemical and gas sensors capable of operating in harsh environment conditions. In this work we present our recent developments on design, fabrication and testing of AlGaN/GaN high electron mobility transistor (HEMT) based sensors for detection of various gases. First, the method of as-fabricated device baseline value stabilization is demonstrated. Secondly, the impact of sensor design is discussed with the emphasis on gate electrode geometry optimizations to enhance sensing performance. Then we present the sensing characteristics of Pt-HEMTs towards H 2 S and compare them to H 2 and NO 2 . Finally we demonstrate recent results of NO 2 detection with Ti/Au based HEMT sensors, which are superior to those using Pt based devices. Accepted author manuscriptElectronic Components, Technology and Material
Viagem ao céu, authored by Monteiro Lobato: Author Philologys Notes
No full textEsta dissertação tem como objetivo investigar as etapas de gênese e estabelecimento da obra Viagem ao céu, de Monteiro Lobato, com a finalidade de identificar, descrever e analisar as alterações atribuídas ao autor ao longo dos anos. O corpus é constituído por 10 testemunhos, publicados entre 1932 e 1948. Partindo dos princípios norteadores da Crítica Genética e da Filologia do Autor, realizam-se, portanto, a recensão de testemunhos e o exame das variantes textuais encontradas. Realiza-se, também, a descrição dos testemunhos de acordo com as determinações da Bibliografia Material. Ao examinar as lições variantes de cada testemunho do texto, foi possível identificar alguns padrões, relacionados à sua classificação e à sua frequência. Identificam-se casos de variação por adição, alteração de ordem, omissão e substituição, além de mudanças na paragrafação e reelaboração textualThe main objective of this dissertation is to investigate the settlement and genesis steps of the literary work named Viagem ao Céu, authored by Monteiro Lobato, to identify, to describe and to analyze the variations conducted on the text during years by the author. The corpus is composed of eight testimonials, published between 1932 and 1948. Considering the guiding fundaments of the Textual Bibliography and the Genetics, this dissertation shows the resumption from the testimonies and the examination of the variants found in the text. The description of the testimonies was also made according to Material Bibliography rules. During the variant lessons survey from each testimony of the text, it was possible to identify some patterns related to its classification and frequency. It was also possible to recognize variations cases by addition, change of order, omissions, and substitutions, besides paragraph and chapter changes and textual rewritin
Simulating multiple diffraction in imaging systems using a path integration method
No full textWe present a method for simulating multiple diffraction in imaging systems based on the Huygens–Fresnel principle. The method accounts for the effects of both aberrations and diffraction and is entirely performed using Monte Carlo ray tracing.We compare the results of this method to those of reference simulations for field propagation through optical systems and for the calculation of point spread functions. The method can accurately model a wide variety of optical systems beyond the exit pupil approximation.Accepted Author ManuscriptImPhys/Optic
Challenges in simulating advanced control methods for AO
No full textThis paper discusses various practical problems arising in the design and simulation of predictive control methods for adaptive optics. Although there has been increased attention towards optimal prediction and control methods for AO systems, they are often tested in simplified simulation environments. The use of advanced AO simulators however, is a valuable alternative to the use of real data or laboratory experiments, as they provide both a flexible environment which is ideal for testing a new algorithm and are more accessible to non-experts. Topics that are often not explicitly discussed, such as the identification of a turbulence dynamics model from data, the use of matrix structures in AO systems to decrease the computational complexity and the implementation of Kalman filters to optimally deal with realistic noise conditions are examined. All topics discussed are illustrated by an accompanying Matlab code, which is based on the existing Matlab AO toolbox OOMAO.Team Raf Van de Pla
Characterization and closed-loop performance of a liquid mirror adaptive optical system
No full textA deformable mirror based on the principle of total internal reflection of light from an electrostatically deformed liquid–air interface was realized and used to perform closed-loop adaptive optical (AO) correction on a collimated laser beam aberrated by a rotating phase disk. Equations describing the resonant and oscillatory behavior of the liquid system were obtained and applied to the system under consideration. Characterization of the mirror included open- and closed-loop frequency responses, determination of rise times, the damping times of the liquid, and the influence of liquid surface motion in the absence of external optical aberrations. The performance of the AO system was determined for static and dynamic aberrations for various sets of system parameters. The predictions of the general expressions were compared to the results of the experimental realization and were found to be in good agreement.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
Counseling in the Manitou, Colorado, junior and senior high school
No full textMay 26, 1932.Includes bibliographical references (pages 67-71).In this study the writer deals chiefly with vocational and educational guidance, with the understanding that health, character and social guidance are included in a lesser degree. The author interprets the aim of the counseling program in educational guidance to be the study of the interests, abilities and aptitudes of the child and the adjustment of the curricular and extra-curricular activities to meet the needs of the individual pupil. This program should also stimulate interests and develop and increase abilities. In short, it is the advisement by a counselor of the curricular subjects in which the student should matriculate as the result of research on the part of the counselor and student. It is very closely allied with health, vocational, social and character guidance, the other factors with which this thesis deals. The author feels that educational guidance should follow the choosing of a vocation and should include information upon courses of study to be pursued which will train the student in his occupational choice
Ethanol Extract of Artemisia Annua Prevents LPS-Induced Inflammation and Blood–Milk Barrier Disruption in Bovine Mammary Epithelial Cells
No full textSIMPLE SUMMARY: Mastitis is one of the most serious diseases restricting the development of the dairy industry. It not only affects bovine production performance, but also leads to antibiotic residues and drug resistance. As antibiotics have gradually been forbidden, it is urgently necessary to find natural alternatives to prevent mastitis. Artemisia annua is an annual low-toxicity herb native to China that is widely distributed around the world. This study aimed to explore whether an ethanol extract of Artemisia annua (AAE) could be used as a new preventive agent to ameliorate LPS-induced inflammation and blood–milk barrier disruption in bovine mammary epithelial cells (bMECs). Our results showed that AAE pretreatment could alleviate inflammatory injury and tight junction abnormalities after LPS challenge, which was partially related to the attenuation of nuclear factor-κB (NF-κB) signaling and the downregulation of CD36 levels. Our study can provide a certain reference value for the development and utilization of plant extracts. ABSTRACT: This experiment evaluated the pre-protective effect of AAE on inflammatory injury and tight junction disturbance in bMECs induced by LPS. The bMECs were treated with AAE (3, 6, 12 μg/mL) for 3 h and then incubated with 10 μg/mL lipopolysaccharide (LPS) for 12 h. Our results showed that LPS significantly increased the mRNA and protein expression of CD36, induced the phosphorylation of IκBα and p65 and elevated the levels of TNF-α, IL-1β and IL-6 mRNA, which further resulted in ultrastructural damage, disrupted the expression of tight junction proteins (occludin, zonula occludens (ZO-1) and claudin-1) and decreased the viability of bMECs (p < 0.05). More importantly, AAE pretreatment attenuated the expression of CD36, suppressed the activity of the NF-κB signaling pathway and down-regulated the levels of inflammatory factors in LPS-stimulated bMECs (p < 0.05). Therefore, AAE can effectively protect bMECs against inflammatory injury and tight junction dysfunction, which has important research value for the prevention of bovine mastitis
Joint optimization of phase diversity and adaptive optics: Demonstration of potential
No full textWe study different possibilities to use adaptive optics (AO) and phase diversity (PD) together in a jointly optimized system. The potential of the joint system is demonstrated through numerical simulations. We find that the most significant benefits are obtained from the improved deconvolution of AO-corrected wavefronts and the additional wavefront sensor (WFS) information that reduces the computational demands of PD algorithms. When applied together, it is seen that the image error can be reduced by 20% compared to traditional PD, working with one focused and one defocused camera image, and the computational load is reduced by a factor of 20 compared to a more reliable PD algorithm requiring more camera images. In addition, we find that the system performance can be optimized by adjusting the magnitude of the applied diversity wavefronts.Delft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Potential use of garlic products in ruminant feeding: A review
No full textThe addition of antibiotics as growth promoters to ruminant feed can result in bacterial resistance and antibiotic residues in ruminant products. Correspondingly, there is serious public concern regarding the presence of antibiotic residue in ruminant products and the consequent threat to human health. As a result, the addition of plants and their products to ruminant feeds, as an alternative to antibiotics, has received much attention recently. Garlic and its products are rich in organosulphur compounds, which have a variety of biological activities and have been widely used as natural additives in animal production. This review presents recent knowledge on the addition of garlic products (powder, skin, oil, leaf and extracts) to the diets of ruminants. In this paper, garlic products are evaluated with respect to their chemical composition, bioactive compounds, and their impacts on the rumen ecosystem, antioxidant status, immune response, parasitic infection, growth performance and product quality of ruminants. This review provides valuable guidance and a theoretical basis for the development of garlic products as green, highly efficient and safe additives, with the aims of promoting ruminant growth and health, reducing methane emissions and improving ruminant product quality. Garlic extracts have the potential to control parasite infections by decreasing the faecal egg count. Garlic powder, oil and allicin are able to reduce the methane emissions of ruminants. Organosulphur compounds such as allicin, which is present in garlic products, have the potential to inhibit membrane lipid synthesis of the archaeal community, thus influencing the population of methanogenic archaea and resulting in a reduction in methane emissions. Some garlic products are also able to increase the average daily gain (garlic skin, water extract, and leaf) and the feed conversion ratio (garlic skin and leaf) of ruminants. Garlic stalk silage fed to sheep has the potential to improve the nutritional value of mutton by increasing the concentrations of linoleic and linolenic acids and essential amino acids. Sheep fed a diet containing garlic powder or oil are able to produce milk with higher concentrations of the conjugated linoleic acids and n-3 fatty acids, which has health benefits for consumers, due to the widely recognized positive impact of n-3 polyunsaturated fatty acids and conjugated linoleic acids on human heart health, improving platelet aggregation, vasodilation and thrombotic tendency. Overall, garlic products have the potential to enhance growth performance and product quality and reduce parasite infections, as well as methane emissions of ruminants
Introdução ao pensamento de Bakhtin
No full textReview of the text “Introduction to the thought of Baktin” (2006), by the author José Luiz de Fiorin.Review of the text “Introduction to the thought of Baktin” (2006), by the author José Luiz de Fiorin.Resenha do texto "Introdução ao pensamento de Baktin" (2006), do autor José Luiz de Fiorin
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