The determination and evaluation of Nitinol constitutive models for finite element analysis

Superelastic Ni-Ti (Nitinol) is a member of the shape memory alloy (SMA) family of metals. The physical properties of Nitinol are highly dependant on a number of factors, including manufacturing method, subsequent processing, operating temperature, and strain rate. These factors complicate the prescription of material constitutive models, leading to complexities in the computational analysis of Nitinol components. The current work explores the limitations in the Nitinol material model available in existing commercial finite element (FE) software using a series of specially design experimental tests and representative FE models

Facility dogs as a tool for building rapport and credibility with child witnesses

The present student examined the perspectives of legal professionals in relation to the use of facility dogs in building rapport and credibility with child witnesses. 70 legal professionals from across North America, who had experience interviewing children, both with and without the use of a facility dog, were recruited to take part in the study. Utilising a holistic mixed-method design, data was collected via an online questionnaire, which asked participants about the impact they felt a facility dog had on rapport and witness credibility during police interviews with children. The results highlighted the positive impact that facility dogs have on child witnesses, not only in helping build rapport and witness credibility, but also for creating a more positive experience for young witnesses going through the criminal justice process. The results therefore provide evidence for the consideration of these dogs in countries beyond North America, as they provide an invaluable service to young witnesses

Student teachers’ understanding and acceptance of evolution and the nature of science

The focus of this study was student teachers at a South African university enrolled in a Bachelor of Education (B.Ed.) programme and a Postgraduate Certificate in Education (PGCE), respectively. The purpose of this study was to explore students’ understanding and acceptance of evolution and beliefs about the nature of science (NOS), and to discover if these understandings and acceptances changed with the level of their studies. In so doing, we wished to determine if there is a relationship between their understanding of evolution and the NOS, and their level of acceptance of evolution. The study is located within a quantitative framework. Questionnaires were administered to pre-service teachers, who were enrolled in the School of Education. All participants had chosen Biology as their teaching specialisation. Three instruments were included in the questionnaires. The findings revealed that students in the B.Ed. programme have a poorer understanding of evolution and NOS than the graduate group (PGCE), and that there is no significant difference in understanding between different levels within the B.Ed. group. A further significant finding was that acceptance of evolution is independent of changes in conceptual understanding of evolution and independent of changes in beliefs about the NOS.Keywords: acceptance; beliefs; evolution; nature of science; understandin

Standards of Capacity

In order to calibrate with precision condensers for use in radio frequency measurements, three standard condensers of coaxial cylindrical plates were made after the manner described by the former Lord Rayleigh. The three condensers were of capacities 25, 50, and 100 micro-micro-farads. By means of continuous wave radio frequency currents from an electron tube generator a variable air condenser with a vernier was calibrated by a step by step method. This was used as a secondary standard. The measurements were accurate to less than one-half micro-micro-farad, and the calibration was correct to considerably less than one per cent, for capacities greater than twenty micro-micro-farads. Measurements showed that isolated metal spheres and metal discs could not be readily used as standards, that is, their calculated and measured capacities were not in agreement because of unavoidable capacity effects. On the other hand, the capacities of small parallel plate variable condensers were found to be in close agreement with the values calculated from the dimensions of the plates and the distance apart of the plates. The plates were of brass 2.5 mm in thickness, the back surfaces being beveled until the edges were thin. The plates were circular, those of one condenser being 7 cms in diameter, of another 10 cms. The distance apart of the plates was varied by a slow screw adjustment

SACOC: A spectral-based ACO clustering algorithm

The application of ACO-based algorithms in data mining is growing over the last few years and several supervised and unsupervised learning algorithms have been developed using this bio-inspired approach. Most recent works concerning unsupervised learning have been focused on clustering, where ACO-based techniques have showed a great potential. At the same time, new clustering techniques that seek the continuity of data, specially focused on spectral-based approaches in opposition to classical centroid-based approaches, have attracted an increasing research interest–an area still under study by ACO clustering techniques. This work presents a hybrid spectral-based ACO clustering algorithm inspired by the ACO Clustering (ACOC) algorithm. The proposed approach combines ACOC with the spectral Laplacian to generate a new search space for the algorithm in order to obtain more promising solutions. The new algorithm, called SACOC, has been compared against well-known algorithms (K-means and Spectral Clustering) and with ACOC. The experiments measure the accuracy of the algorithm for both synthetic datasets and real-world datasets extracted from the UCI Machine Learning Repository

Histopathologic alterations associated with the transplanted homologous dog liver

Homotransplanted livers in dogs developed mononuclear, lymphocytic and plasmacytic infiltration and hepatic cell degeneration roughly paralleling survival time. Extensive histologic alterations of host reticuloendothelial structures occurred. Proliferation and infiltration of mononuclear cells, principally plasmacytes, were noted in lung, kidney, perirenal supportive tissue, bone marrow, and lymph nodes. Lymph nodes, in addition, were characterized by cortical and follicular depletion. These changes were considered to represent extensive host reticuloendothelial mobilization coincident to liver homotransplant rejection. The relation between these alterations and those found in other hypersensitivity states is discussed. © 1962

The transition of smooth muscle cells from a contractile to a migratory, phagocytic phenotype : direct demonstration of phenotypic modulation

Atherosclerotic plaques are populated with smooth muscle cells (SMCs) and macrophages. SMCs are thought to accumulate in plaques because fully-differentiated, contractile SMCs reprogram into a ‘synthetic’ migratory phenotype, so-called phenotypic modulation, whilst plaque macrophages are thought to derive from blood-borne myeloid cells. Recently, these views have been challenged, with reports that SMC phenotypic modulation may not occur during vascular remodelling and that plaque macrophages may not be of haematopoietic origin. Following the fate of SMCs is complicated by the lack of specific markers for the migratory phenotype and direct demonstrations of phenotypic modulation are lacking. Therefore, we employed long-term, high-resolution, time-lapse microscopy to track the fate of unambiguously identified, fully-differentiated, contractile SMCs in response to the growth factors present in serum. Phenotypic modulation was clearly observed. The highly-elongated, contractile SMCs initially rounded up, for 1-3 days, before spreading outwards. Once spread, the SMCs became motile and displayed dynamic cell-cell communication behaviours. Significantly, they also displayed clear evidence of phagocytic activity. This macrophage-like behaviour was confirmed by their internalisation of 1µm fluorescent latex beads. However, migratory SMCs did not uptake acetylated low-density lipoprotein or express the classic macrophage marker CD68. These results directly demonstrate that SMCs may rapidly undergo phenotypic modulation and develop phagocytic capabilities. Resident SMCs may provide a potential source of macrophages in vascular remodelling

Appearance-based localization for mobile robots using digital zoom and visual compass

This paper describes a localization system for mobile robots moving in dynamic indoor environments, which uses probabilistic integration of visual appearance and odometry information. The approach is based on a novel image matching algorithm for appearance-based place recognition that integrates digital zooming, to extend the area of application, and a visual compass. Ambiguous information used for recognizing places is resolved with multiple hypothesis tracking and a selection procedure inspired by Markov localization. This enables the system to deal with perceptual aliasing or absence of reliable sensor data. It has been implemented on a robot operating in an office scenario and the robustness of the approach demonstrated experimentally

Identifying dynamical systems with bifurcations from noisy partial observation

Dynamical systems are used to model a variety of phenomena in which the bifurcation structure is a fundamental characteristic. Here we propose a statistical machine-learning approach to derive lowdimensional models that automatically integrate information in noisy time-series data from partial observations. The method is tested using artificial data generated from two cell-cycle control system models that exhibit different bifurcations, and the learned systems are shown to robustly inherit the bifurcation structure.Comment: 16 pages, 6 figure