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Polymers are increasingly being used in engineering designs due to their favorable mechanical properties such as high specific strength, corrosive resistance, manufacturing flexibility. The understanding of the mechanical behavior of these polymers under both static and dynamic loading is critical for their optimal implementation in engineering applications. One such polymer utilized in a wide variety of applications from medical instrumentation to munitions is Polyetherimide, referred to as Ultem. This thesis characterizes both the static and dynamic mechanical behavior of Ultem 1000 through experimental methods and numerical simulations. Standard compression experiments were conducted on and MTS test frame to characterize the elastic-plastic behavior of Ultem 1000 under quasi-static conditions. The dynamic response of the material was investigated at very high strain rates using a custom built miniaturized Kolsky bar apparatus. The smaller Kolsky bar configuration was chosen over the conventional Kolsky device to increase the maximum capable strain rates and to reduce common experimental problems such as wave dispersion, friction, and stress equilibrium. Since a universal test standard for this apparatus is not available, the details of the design, construction, and experimental procedures of this device are provided. The results of the high strain rate testing revealed a bilinear relationship between the material yield stress and strain rate. This relationship was modeled using the Ree-Eyring two stage activation process equation.

The split Hopkinson bar test is the most commonly used method for determining material properties at high rates of strain. The theory governing the specifics of Hopkinson bar testing has been around for decades. It has only been the last decade or so, however, that significant data processing advancements have been made. It is the intent of this thesis to offer the insight of its author towards new advancements. The split Hopkinson bar apparatus consists of two long slender bars that sandwich a short cylindrical specimen between them. By striking the end of a bar, a compressive stress wave is generated that immediately begins to traverse towards the specimen. Upon arrival at the specimen, the wave partially reflects back towards the impact end. The remainder of the wave transmits through the specimen and into the second bar, causing irreversible plastic deformation in the specimen. It is shown that the reflected and transmitted waves are proportional to the specimen's strain rate and stress, respectively. Specimen strain can be determined by integrating the strain rate. By monitoring the strains in the two bars, specimen stress-strain properties can be calculated. Several factors influence the accuracy of the results, including longitudinal wave dispersion, impedance mismatch of the bars with the specimens, and transducer properties, among others. A particular area of advancement is a new technique to determine the bars dispersive nature, and hence reducing the distorting effects. By implementing numerical procedures, precise alignment of the strain pulses is facilitated. It is shown that by choosing specimen dimensions based on their impedance, the transmitted stress signal-to-noise ratio can be improved by as much as 25dB. An in depth discussion of realistic expectations of strain gages is presented, along with closed form solutions validating any claims. The effect of windowing on the actual strains is developed by analyzing the convolution of a rectangular window with the impact pulse. The thesis concludes with a statistical evaluation of test results. Several recommendations are then made for pursuing new areas of continual research. / Master of Science

In structural concrete, hooked bars are used to shorten anchorage length when the requirements for straight bar anchorage cannot be provided within the available dimensions of elements. The objective of this study was to provide an overview of hooked bar anchorage. Design examples and structural details are based on Building code requirements for structural concrete (ACI 318-08) and commentary. Examples of standard hooks in exterior beam-column joint and hooked bar anchorage details for reinforced concrete beam-SRC column joints are discussed. The general behavior of anchorage of hooked reinforcing bars is summarized from a review of previous studies. Then, design requirements for the development length of standard hook are discussed and used in an example. An example of the use of hooked bars in reinforced concrete beam-SRC column joint is provided. Four options for short development length are presented and compared: Adding more reinforcement, welding bars, confinement by steel column flanges, and anchorage by plate welded between flanges. / text

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In this work, three aluminum sheet alloys, AA5754, AA5182 and AA6111, which are prime candidates for replacing mild steel in automobile structures, are tested in tension at quasi-static and high strain rates. <br /><br /> In order to characterize the constitutive response of AA5754, AA5182 and AA6111 at high strain rates, tensile experiments were carried out at strain rates between 600 s^-1 and 1500 s^-1, and at temperatures between ambient and 300??C, using a tensile split Hopkinson bar (TSHB) apparatus. As part of this research, the apparatus was modified in order to provide an improved means of gripping the sheet specimens. Quasi-static experiments also were conducted using an Instron machine. <br /><br /> The experimental data was fit to the Johnson-Cook and Zerilli-Armstrong constitutive models for all three alloys. The resulting fits were evaluated by numerically simulating the tensile experiments conducted using a finite element approach.

The performance of Uneven Parallel Bar skills by junior high girls is hindered by blister formation on the hands. The problem was to investigate certain measures relative to their value in blister prevention.

La déontologie constitue, de tout temps, un élément essentiel de la profession d'avocat. Constituée d'un ensemble de règles, dont certaines restent purement coutumières, elle est ce qui fait de l'avocat bien plus qu'un simple auxiliaire de la justice. S'il demeure incontestable que l'ensemble des barreaux français adopte, et depuis très longtemps, une attitude commune sur les principes, en partie dictée par le puissant barreau de Paris, il n'en est pas moins vrai, que les barreaux de province, et notamment ceux du sud-est, ont toujours fait preuve d'indépendance, préférant, bien souvent, l'esprit à la lettre. Leur position en ce qui concerne principalement la recherche de clientèle et la lutte contre les réseaux d'affaires est incontestablement courageuse. La réponse qu'ils donnent au délicat de problème de l'honoraire est novatrice. Les Conseils de l'Ordre, principalement dans le Sud-Est, avant d'être des organes de sanction, sont avant tout des organes de conseil. Ceux du ressort de la Cour d'appel d'Aix-en-Provence font de la conservation des traditions un devoir et de la modération une vertu. / Legal ethics have always been an essential part of legal business. Made up of a set of rules, some of which are merely customary rules, legal ethics lead the lawyer to be more than an aid of the justice. One usually notice the common, very ancient and general agreement of all french Bars on some principles, behaviour partly dictated by the powerful Bar of Paris. However, it’s also true that other Bars, in particular those of the South-East of France from Marseille to Nice, have always shown a real independence in the application of such principles, liking better the spirit of these rules than their letter. Regarding the search for customers and the wrestling against business networks, the positions of these bars is unarguably brave. The solution they give to the delicate problem of the fees of the lawyer are innovative. The Bars’ Councils, mainly in the South-East of the France, besides being organs of penalty for their profession, are especially organs of reflexion ans council. Those depending of the competence of the Court of Appeal of Aix-en-Provence, carry out the duty to defend the traditions and consider moderation as virtue.

Li, Chak Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 150-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

Concerns regarding the decreasing population of the American eel (reported by Castonguay et al. 1994; Haro et al. 2000) have led to design restrictions for hydropower facilities in the Eastern United States. However, the effects of these restrictions on eel passage and their impacts on power generation have not been fully researched. The goal of this study was to evaluate design parameters for bar racks that have potential to prevent entrainment of silver American eels, but also have minimal impacts on power generation. Hydraulic and biological assessments were used to determine the role of bar spacing, rack angle, and approach velocity on head loss across bar racks and the effects of bar spacing and approach velocity on eel bypass efficiency. The hydraulic assessments included computational fluid dynamics (CFD) analyses and laboratory experiments conducted in a re-circulatory flume at Alden Research Laboratory (Alden) in Holden MA. The flume allowed for determination of head losses across bar racks placed at angles of 45 and 90 degrees to the flow direction, with bar spacings of 0.75, 1.0 and 1.5 inches (19, 25 and 38 mm) and approach velocities of 1.5, 2.0 and 2.5 ft/sec (0.46, 0.61 and 0.76 m/s). Biological assessment, supported by funding from the Electric Power Research Institute (EPRI), used the same flume and included experiments with a 90 degree rack angle, bar spacings of 0.75 and 1.0 inches (19 and 25 mm), and approach velocities of 1.5 and 2.0 ft/sec (0.46 and 0.61 m/s). Bypass efficiencies, defined by the percentage of eels moving through the bypass, were evaluated for eels using three 2-hour replicate trials with nighttime releases of 30 eels per trial. Eel behavior in the vicinity of the racks was observed to the extent possible using a DIDSON acoustic camera. Experiments for the 90 degree configuration showed that the guidance efficiencies for the 0.75 inch (19 mm) spacing were greater than those for the 1.0 inch (25 mm) spacing, while the head losses for the 0.75 inch (19 mm) spacing exceeded the head losses for the 1.0 inch (25 mm) spacing by more than 10 percent. Linear regression analysis indicated that 53 percent of the variations in head width are explained by changes in the length of the eel. Results of the hydraulic evaluations were used to develop a new head loss equation that has a correlation coefficient of 98.6 percent. The results of the hydraulic and biological assessments provide a basis for quantifying the impacts of bar rack design on hydropower operation and downstream passage for American eels.