The purpose of this project was to initiate development of a nonrefrigerated dairy dessert product. Milk was concentrated by pressure-driven filtration and then sterilized using ultra-high temperature (UHT) processing. Following sterilization, samples were aseptically inoculated with rennet to coagulate the milk, which was then stored at room temperature. These processing steps produced a dairy dessert that did not require refrigeration. I investigated the influence of total solids, milk fat, rennet dosage, storage temperature, and storage time on curd firmness and syneresis. I investigated the effect on curd firmness and syneresis of giving the concentrate a heat treatment prior to UHT processing. Chocolate and vanilla dairy desserts were prepared, and a taste panel was conducted to compare the dairy dessert with a ready-to- eat starch-based pudding. Milk concentrate obtained by reverse osmosis did not form a gel, whereas concentrate obtained by ultrafiltration did gel. Increasing the solids content of the milk concentrate increased curd firmness, but increasing the fat content of the concentrate decreased curd firmness. Curd firmness and syneresis increased as the concentration of rennet was increased. Products stored at 21°C yielded firmer gels with more syneresis than products stored at 4°C. Moreover, products stored for longer periods of time produced firmer gels and greater amounts of syneresis. Concentrate that received a batch heat treatment prior to sterilization reduced syneresis. The addition of cocoa to the concentrate inhibited coagulation. Taste panelists preferred the commercial pudding over the dairy

The concrete maturity method can be utilized to determine in situ strength of concrete. It uses the temperature of concrete to determine a maturity index that can then be used to determine strength of concrete. However, monitoring the concrete temperature using thermocouples brings up a wiring issue, which is not advisable in an equipment and human intensive area like a construction site. One of the ways to get around this wiring issue is to use Radio Frequency Identification (RFID) technology, which is capable of transmitting information wirelessly. Previous research implemented using ultra high frequency RFID tags embedded in fresh concrete found that water could be the impediment for transmitting RFID signal from within concrete during early stages of curing. From literature it was found that lower the frequency, better the chances of the wave penetrating water. The objective of the research was to figure out whether the frequency of RFID tags has any relationship with the readability of RFID tags embedded in fresh concrete. For this investigation, low frequency, high frequency, and ultra high frequency RFID tags were tested within fresh concrete to see any difference between tags in terms of transmitting information. This experiment was carried out in a controlled space to reduce the number of variables affecting the experiment outcome. The low frequency, high frequency, and ultra high frequency RFID tags were placed within 2 in x 3 in x 2 in wooden formwork at a depth of 4 in, 8 in, and 12 in. Ready mix concrete was poured into the formwork and 3 concrete cubes were cast with the tags embedded within them. Readers that could be connected to a laptop were used to monitor and collect the time at which these RFID tags can be detected. The test showed that the RFID signals from the low frequency tags at all depths were detected as soon as concrete was poured. The Ultra High Frequency tags placed at the 4" level could be detected 15 minutes after concrete was poured. The UHF tags at the 8" level could be detected after 30 minutes. The UHF tags at the 12" level took on an average 2 hours to be detected from the vicinity of the formwork. The greater the depth at which the ultra high frequency tag was buried the longer it took for it to be detected. The high frequency tags could be detected only at the 4" level. The reason the performance of the HF card degraded in concrete could be because it uses an aluminum foil antenna which is more susceptible to the environment changing the relative permeability. A copper wire antenna could have fared better in this condition, increasing the chances of detecting the tag. Moreover a passive tag was used. The read range and chances of detection could have been increased had an active tag been used. The power of the reader that was used was also very less which might have contributed to the tag not being detected. Among the tags that were used in the experiment it was found that low frequency tags was the tag that could be detected the earliest after concrete was poured into the forms. However, the maximum read range of the tag observed in the experiment was 20" which is too small a distance to be used on an actual construction site.

Ultra-high molecular weight polyethylene (UHMWPE) is used worldwide as a bearing material in total joint replacement prostheses. Despite its excellent biocompatibility and high wear resistance, wear of UHMWPE components continues to be a major problem limiting the clinical lifespan of UHMWPE-containing orthopaedic implant devices. Multi-directional motion or cross-path motion is known to affect wear rates of UHMWPE in total knee and hip replacement prostheses. The purpose of this study was to quantify the effect of counterface roughness on the cross-path wear of UHMWPE and to determine if the previously established unified theory of wear model could accurately predict wear rates in an abrasive wear environment. UHMWPE pins were articulated against both smooth (centerline roughness, Ra, of 0.015 µm) and rough (Ra = 0.450µm) cobalt-chromium counterfaces in a series of six rectangular wear paths (width = A, length = B) with systematically increasing aspect ratios (B/A) and linear tracking (A = 0), all with identical path lengths (20mm) per cycle. Gravimetric weight loss was converted into volumetric wear rates and wear factors, k. The results showed that for both smooth and rough-counterface tests, wear reached a maximum when a 3mmx7mm wear path was employed. The unified theory of wear was generally accurate in predicting wear rates; however, for rough-counterface tests there was a larger increase in the wear factor for higher aspect ratio rectangular wear paths. The ratio [k rough/ k smooth] decreased monotonically as a function of increasing width of rectangles, normalized by total path length, or A/(A +B). This study showed that wear of UHMWPE articulating in a rectangular motion path likely occurs via a two-step mechanism beginning with molecular orientation followed by material fracture from the UHMWPE surface. The models inability to accurately predict UHMWPE wear for rectangular paths with lower aspect ratios suggests that there may be other operative wear mechanisms including significant re-orientation in the perpendicular sliding direction. In conclusion, it is possible to predict the wear behavior of UHMWPE using mathematical models. A robust model would have an important role in characterizing and predicting performance of currently used and potential future orthopaedic implant materials.

Application of mechanical micromachining for fabricating complex three-dimensional (3D) micro-scale features and small parts on a broad range of materials has increased significantly in the recent years. In particular, mechanical micromachining finds applications in manufacturing of biomedical devices, tribological surfaces, energy storage/conversion systems, and aerospace components. Effectively addressing the dual requirements for high accuracy and high throughput for micromachining applications necessitates understanding and controlling of dynamic behavior of micromachining system, including positioning stage, spindle, and the (micro-) tool, as well as their coupling with the mechanics of the material removal process. The dynamic behavior of the tool-collet-spindle-machine assembly, as reflected at the cutting edges of a micro-tool, often determines the achievable process productivity and quality. However, the common modeling techniques (such as beam based approaches) used in macro-scale to model the dynamics of cutting tools, cannot be used to accurately and efficiently in micro-scale case. Furthermore, classical modal testing techniques poses significant challenges in terms of excitation and measurement requirements, and thus, new experimental techniques are needed to determine the speed-dependent modal characteristics of miniature ultra-high-speed (UHS) spindles that are used during micromachining. The overarching objective of this thesis is to address the aforementioned issues by developing new modeling and experimental techniques to accurately predict and analyze the dynamics of micro-scale cutting tools and miniature ultra-high-speed spindles, including rotational effects arising from the ultra high rotational speeds utilized during micromachining, which are central to understanding the process stability. Accurate prediction of the dynamics of micromachining requires (1) accurate and numerically-efficient analytical approach to model the rotational dynamics of realistic micro-tool geometries that will capture non-symmetric bending and coupled torsional/axial dynamics including the rotational/ gyroscopic effects; and (2) new experimental approaches to accurately determine the speed-dependent dynamics of ultra-high-speed spindles. The dynamic models of cutting tools and ultra-high-speed spindles developed in this work can be coupled together with a mechanistic micromachining model to investigate the process stability of mechanical micromachining. To achieve the overarching research objective,first, a new three-dimensional spectral- Tchebychev approach is developed to accurately and efficiently predict the dynamics of (micro) cutting tools. In modeling the cutting tools, considering the efficiently and accuracy of the solution, a unified modeling approach is used. In this approach, the shank/taper/extension sections, vibrational behavior of which exhibit no coupling between different textural motion, of the cutting tools are modeled using one-dimensional (1D) spectral-Tchebychev (ST) approach; whereas the fluted section (that exhibits coupled vibrational behavior) is modeled using the developed 3D-ST approach. To obtain the dynamic model for the entire cutting tool, a component mode synthesis approach is used to `assemble' the dynamic models. Due to the high rotational speeds needed to attain high material removal rate while using micro tools, the gyroscopic/rotational effects should be included in predicting the dynamic response at any position along the cutting edges of a micro-tool during its operation. Thus, as a second step, the developed solution approach is improved to include the effects arising from the high rotational speeds. The convergence, accuracy, and efficiency of the presented solution technique is investigated through several case studies. It is shown that the presented modeling approach enables high-fidelity dynamic models for (micro-scale) cutting-tools. Third, to accurately model the dynamics of miniature UHS spindles, that critically affect the tool-tip motions, a new experimental (modal testing) methodology is developed. To address the deficiency of traditional dynamic excitation techniques in providing the required bandwidth, repeatability, and impact force magnitudes for accurately capturing the dynamics of rotating UHS spindles, a new impact excitation system (IES) is designed and constructed. The developed system enables repeatable and high-bandwidth modal testing of (miniature and compliant) structures, while controlling the applied impact forces on the structure. Having developed the IES, and established the experimental methodology, the speed-dependent dynamics of an air bearing miniature spindle is characterized. Finally, to show the broad impact of the develop modeling approach, a macro-scale endmill is modeled using the presented modeling technique and coupled to the dynamics of a (macro-scale) spindle, that is obtained experimentally, to predict the tool-point dynamics. Specific contributions of this thesis research include: (1) a new 3D modeling approach that can accurately and efficiently capture the dynamics of pretwisted structures including gyroscopic effects, (2) a novel IES for repeatable, high-bandwidth modal testing of miniature and compliant structures, (3) an experimental methodology to characterize and understand the (speed-dependent) dynamics of miniature UHS spindles.

Ultra-High-Performance Concretes (UHPCs) are a promising class of cementitious materials possessing mechanical properties superior to those of Normal Strength Concretes (NSCs). However, UHPCs have been slow to transition from laboratory testing to insertion in new applications, partly due to an intuitive trial-and-error materials development process. This research seeks to addresses this problem by implementing a materials design process for the design of UHPC materials and structures subject to blast loads with specific impulses between 1.25- and 1.5-MPa-ms and impact loads resulting from the impact of a 0.50-caliber bullet travelling between 900 and 1,000 m/s. The implemented materials design process consists of simultaneous bottom-up deductive mappings and top-down inductive decision paths through a set of process-structure-property-performance (PSPP) relations identified for this purpose. The bottom-up deductive mappings are constructed from a combination of analytical models adopted from the literature and two hierarchical multiscale models developed to simulate the blast performance of a 1,626-mm tall by 864-mm wide UHPC panel and the impact performance of a 305-mm tall by 305-mm wide UHPC panel. Both multiscale models employ models at three length scales – single fiber, multiple fiber, and structural – to quantify deductive relations in terms of fiber pitch (6-36 mm/revolution), fiber volume fraction (0-2%), uniaxial tensile strength of matrix (5-12 MPa), quasi-static tensile strength of fiber-reinforced matrix (10-20 MPa), and dissipated energy density (20-100 kJ/m²). The inductive decision path is formulated within the Inductive Design Exploration Method (IDEM), which determines robust combinations of properties, structures, and processing steps that satisfy the performance requirements. Subsequently, the preferred material and structural designs are determined by rank order of results of objective functions, defined in terms of mass and costs of the UHPC panel.

When compared to traditional concrete, steel fibre reinforced concrete (SFRC) shows several enhancements in performance, including improved tensile resistance, toughness and ductility. One potential application for SFRC is in columns where the provision of steel fibres can improve performance under axial and lateral loads. The use of SFRC can also allow for partial replacement of transverse reinforcement required by modern seismic codes. To improve workability, self-consolidating concrete (SCC) can be combined with steel fibres, leading to highly workable SFRC suitable for structural applications. Recent advances in material science have also led to the development of ultra-high performance fibre reinforced concretes (UHPFRC), a material which exhibits very high compressive strength, enhanced post-cracking resistance and high damage tolerance. In heavily loaded ground-story columns, the use of UHPFRC can allow for reduced column sections. This thesis presents the results from a comprehensive research program conducted to study the axial behaviour of columns constructed with highly workable SFRC and UHPFRC. As part of the experimental program, twenty-three full-scale columns were tested under pure axial compressive loading. In the case of the SFRC columns, columns having rectangular section and constructed with SCC and steel fibres were tested, with variables including fibre content and spacing of transverse reinforcement. The results confirm that use of fibres results in improved column behaviour due to enhancements in core confinement and cover behaviour. Furthermore, the results demonstrate that the provision of steel fibres in columns can allow for partial replacement of transverse reinforcement required by modern codes. The analytical investigation indicates that confinement models proposed by other researchers for traditional RC and SFRC can predict the response of columns constructed with SCC and highly workable SFRC. In the case of the UHPFRC columns, variables included configuration and spacing of transverse reinforcement. The results demonstrate that the use of appropriate detailing in UHPFRC columns can result in suitable ductility. Furthermore, the results demonstrate the improved damage tolerance of UHPFRC when compared to traditional high-strength concrete. The analytical investigation demonstrates the need for development of confinement models specific for UHPFRC.

The design and construction of a state-of-the-art ultra-high vacuum spectrometer for the performance of angle-resolved inverse photoemission spectroscopy is presented. Detailed descriptions of its most important components are included, especially the Geiger-Muller ultraviolet photodetectors. By building on recent developments in the literature, we expect our spectrometer to achieve resolution comparable or superior to that of other prominent groups, and in general be one of the foremost apparatus for studying the momentum dependence of the unoccupied states in strongly correlated materials. Summaries of the theory of angle-resolved inverse photoemission spectroscopy and the basics of ultra-high vacuum science are also included.

Gegenstand der Arbeit ist die PFG NMR (nuclear magnetic resonance with pulsed field gradients), wobei speziell die apparativen und experimentellen Bedingungen untersucht werden, welche sich durch die Verwendung ultra-hoher gepulster magnetischer Feldgradienten von bis zu 35T/m ergeben. Motiv für die Arbeit ist die Untersuchung von Diffusionserscheinungen in mikroporösen Wirtssystemen mit inneren magnetischen Feldgradienten oder/und kurzen T2-Relaxationzeiten. Nach Zusammenstellung der notwendigen Werkzeuge zur mathematischen Beschreibung von PFG NMR-Experimenten werden die aus der Literatur bekannten Impulssequenzen kritisch untersucht und durch eigene Weiterentwicklungen ergänzt. Für wichtige PFG NMR-Impulssequenzen wird eine verallgemeinerte Schreibweise vorgestellt und auf beliebige Formen der gepulsten magnetischen Feldgradienten ausgedehnt. Weiterhin werden Störeinflüsse auf das PFG NMR-Experiment untersucht und zunächst in allgemeiner Form Möglichkeiten zu deren Beseitigung bzw. Unterdrückung dargestellt. Die so gewonnenen Erkenntnisse fanden konkrete Anwendung bei der Konzeption und dem Bau des PFG NMR-Spektrometers Fegris 400 NT. Dieses Gerät wird, soweit es den Gegenstand der Arbeit berührt, ebenfalls beschrieben und in der Anlage dokumentiert. Abschließend sind einige Untersuchungen, die mit dem Fegris 400 NT durchgeführt wurden und in der dargestellten Form erst mit diesem Gerät möglich waren, kurz skizziert, wobei für weitergehende Informationen auf die entsprechenden Veröffentlichungen verwiesen wird.

The design and construction of a state-of-the-art ultra-high vacuum spectrometer for the performance of angle-resolved inverse photoemission spectroscopy is presented. Detailed descriptions of its most important components are included, especially the Geiger-Muller ultraviolet photodetectors. By building on recent developments in the literature, we expect our spectrometer to achieve resolution comparable or superior to that of other prominent groups, and in general be one of the foremost apparatus for studying the momentum dependence of the unoccupied states in strongly correlated materials. Summaries of the theory of angle-resolved inverse photoemission spectroscopy and the basics of ultra-high vacuum science are also included.

This thesis investigates the behaviour of UHPC as a fill material for precast deck panels subjected to negative bending. Two full-scale test specimens were constructed. The transverse joints between the panels, the shear pockets, and the deck haunches were all filled with UHPC. A total of four tests were performed including two static tests to failure and two fatigue tests, one of which was performed to failure. Testing consisted of a loading apparatus acting upwards on the deck soffit in an attempt to impose tensile stresses across the transverse joints, representing the conditions that a transverse joint in the negative moment region of a continuous bridge deck would experience. It was concluded that the transverse UHPC joint performed satisfactorily by transferring bending stresses and shear stresses across the joint from one panel to the adjacent panel. Overall, the test specimens displayed performance levels expected from conventional cast-in-place concrete deck alternatives. / February 2016