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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.
31

The study of temperature oefficient of SAW frequency for AlN thin films on LiNbO3 and ST-quartz

Lee, Yi-Hung 12 July 2002 (has links)
In this study, we use the reactive rf magnetron sputtering method with deposition parameters of RF power of 370W, sputtering pressure of 15 mTorr, substrate temperature of 400¢J, nitrogen concentration (N2/N2+Ar) of 30% and 40%, to deposit highly c-axis orientation AlN thin films on Z-cut LiNbO3 and ST-cut quartz piezoelectric substrate, respectively. The material characteristics of AlN films deposited on Z-cut LiNbO3 and ST-cut quartz substrate with different thickness were obtained by means of the analyses of XRD, SEM and AFM. Besides, the interdigital transducers (IDTs) were fabricated on the bi-layers structure. The AlN film thickness of piezoelectric bi-layers structure was varied in order to discuss its effect on SAW devices and the temperature coefficient of frequency (TCF) of AlN. From the experimental results, it reveals that the center frequency and TCF of SAW filters increase with the increased AlN thin film thickness. Besides it can be concluded that poly-crystalline AlN exhibits a positive temperature coefficient of frequency (TCF).
32

Investigating raptor migration behavior using orientation cages and wing measurements : a comparison of the flammulated owl and northern saw-whet owl in southwestern Idaho /

Smith, Rhonda F. January 2009 (has links)
Thesis (M.S.)--Boise State University, 2009. / Includes abstract. Includes bibliographical references.
33

Saw palmetto a phytochemical study of the fruit of Sabal serrulata /

Mann, Charles August. January 1915 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1915. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 52-60).
34

Investigating raptor migration behavior using orientation cages and wing measurements a comparison of the flammulated owl and northern saw-whet owl in southwestern Idaho /

Smith, Rhonda F. January 2009 (has links)
Thesis (M.S.)--Boise State University, 2009. / Title from t.p. of PDF file (viewed Feb. 16, 2010). Includes abstract. Includes bibliographical references.
35

Design and fabrication of a SAW device for gas detection

Du Plessis, Hercules Gerhardus 03 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Please refer to full text for abstract.
36

Reciprocating saws as tools of dismemberment: analysis of class characteristics and practical utility

Berger, Jacqueline 12 July 2017 (has links)
The present research examined the features that may differentiate cuts made in bone by mechanical and hand-powered saws, specifically investigating the characteristics of commercially available reciprocating saws. The partial limbs of adult white-tailed deer (Odocoileus virginianus) were used as a proxy for human remains, and were cut using five commercially available reciprocating saw blades and a hand-powered hacksaw. The reciprocating blades tested ranged from five teeth-per-inch to 14/18 teeth-per-inch and included raker, alternating, and wavy tooth sets. The hacksaw blade had 32 teeth-per-inch, with wavy set teeth. All the blades examined were intended to cut wood, metal, or both materials. The resulting false start kerfs and complete kerfs on the remains were then examined macroscopically and microscopically. The present study utilized both qualitative and quantitative analysis to examine kerf features that characterize reciprocating saws. The presentation of specific features within the kerf varied based upon blade properties, how the implement was powered, and how it was wielded in reference to the material. The results of the present study demonstrated that significant differences do exist between reciprocating saw blades. Kerf characteristics in which significant differences were noted include: kerf false start (cross section) shape, frequency of cut surface drift, presence of harmonics, striation regularity, and exit chipping size. Inter-blade differences generally reflect class characteristics previously established for hand-powered blades, though reciprocating blades do not strictly follow these categorizations (Symes 1992; Symes et al. 1998, 2010). Identification of inter-blade differences allows the limited identification of sub-classes within reciprocating saws based on the above characteristics, though blades cannot be uniquely identified. Additionally, interior exit chipping was noted, which has not been mentioned in previous sharp force trauma research. Ultimately, this research has applications for sharp force trauma analysis and further aids in the identification of reciprocating saw use in a forensic context, including dismemberments.
37

Protocolo para evaluar el perfil de seguridad de un extracto de CO2 fluido supercrítico de Saw palmetto (Serenoa repens W. Bartram)

Peredo Silva, Liliana January 2010 (has links)
Memoria de Título para optar al título de Química Farmacéutica / Los extractos herbales deben ser evaluados en cuanto a eficacia y seguridad. Estudios de toxicidad aguda in vivo deben considerar los diferentes mecanismos por los cuales los principios activos pueden producir toxicidad. Por consiguiente, se desarrolló una metodología para examinar parámetros generales relacionados con la respuesta de toxicidad aguda. Para ello se utilizaron ratas Sprague-Dawley machos las cuales fueron tratadas con dos dosis de Saw Palmetto, Serenoa repens W. Bartram HiPower® (la dosis recomendada para humanos y una dosis 10 veces mayor) durante 10 días. Se evaluaron los parámetros generales homeostáticos (hemograma y perfil bioquímico), así como características morfológicas de tejidos involucrados en la respuesta a xenobióticos (hígado, timo, bazo y ganglios linfáticos). Todos los parámetros analizados no fueron significativamente diferentes en el grupo control como en los tratados con ambas dosis de Saw Palmetto, HiPower®, sugiriendo que este preparado comercial presenta un buen perfil de seguridad durante el periodo de tratamiento evaluado. La diferencia en las dosis utilizadas fue un orden de magnitud y a pesar de ello, no se observaron alteraciones en los parámetros medidos. El protocolo utilizado en este estudio podría ser utilizado para ensayar la toxicidad aguda in vivo de diferentes extractos herbales. / Herbal extracts must be evaluated for their efficacy and safety. In vivo acute toxicity studies must consider the different mechanisms by which active compounds may elicit toxicological outcomes. Thus, a methodology to test general parameters related to acute toxicity responses in a murine model was developed, using a Saw Palmetto, Serenoa repens W. Bartram extract (HiPower®): adult male Sprague-Dawley rats were treated orally with two doses of Saw Palmetto (the recommended dose for humans and a dose 10-fold higher) for 10 days, to examine general homeostatic parameters (hemogram and clinical chemistry) as well as morphological features of tissues involved in the response to xenobiotics (liver, timus, spleen, and lymphatic ganglia). All the parameters assayed did not undergo significant changes during treatment, suggesting that the commercial extract of Saw Palmetto HiPower® displays a good safety profile for the period tested. The doses assayed spanned over one order of magnitude in the drug concentration and we did not observe differences in the parameters assayed. This method may be adopted for testing the in vivo acute toxicity of any herbal extracts
38

Numerická simulace navařování rotoru turbíny / Numeric simulation of the turbine rotor surfacing

Durajová, Věra January 2010 (has links)
The project elaborated in frame of engineering studies, solves the problem of restoration of the damaged hinge groove blades, and the surfacing of cylindrical faces of the SAW method, using additional material TOPCORE 838 B. The turbine rotor is made from steel with high resistance temperature 30CrMoNiV5-11. Based on literature studies and issues surfacing calculation, it was established that will preheat the material. The issue was solved by using simulation program SYSWELD.
39

Wireless Authentication Using Remote Passwords

Harding, Andrew S. 08 January 2008 (has links) (PDF)
Current authentication methods for wireless networks are difficult to maintain. They often rely on globally shared secrets or heavyweight public-key infrastructure. Wireless Authentication using Remote Passwords (WARP) mitigates authentication woes by providing usable mechanisms for both administrators and end-users. Administrators grant access by simply adding users' personal messaging identifiers (e.g., email addresses, IM handles, cell phone numbers) to an access control list. There is no need to store passwords or other account information. Users simply prove ownership of their authorized identifier to obtain wireless access.
40

Design of Wideband Linear Phase Surface Acoustic Wave Filters

Slater, Nicholas 06 1900 (has links)
<p> A two-part scheme for the design of wideband linear phase SAW filters is proposed. The design uses curved finger interdigital transducers, and extension of slanted finger design, to compensate for circuit effects and eliminate the need for matching. Theory is combined with distortion minimizing techniques to realize devices which satisfy INTELSAT filter specifications. </p> <p> Basic SAW theory is reviewed. and curved finger theory presented, while methods of distortion minimization are both reviewed and proposed. Experimental results which illustrate and support the theory given are included. </p> / Thesis / Master of Engineering (MEngr)

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