The Future of the Home Video Industry : Consumer Trends and Attitudes

This exploratory survey of retailers was done in an effort to determine consumer buying habits and attitudes toward the purchase of a home video system, and to pinpoint patterns and trends, in order to provide the kind of information needed to make wise marketing decisions and to increase industry cooperation. [This is an excerpt from the abstract. For the complete abstract, please see the document.

Study of stochastic aspects in the modeling of the strain-induced crystallization in unfilled polymers

The present contribution deals with the mechanical modeling of the crystallization of unfilled polymers under consideration of stochastic aspects of the process. The framework applied is thermodynamically consistent. The model involves the diameter of crystalline regions and the distance between these regions as internal variables. The necessary evolution equations are based on the assumptions for the effective free energy and the dissipation potential of a control volume. A distribution function is introduced to express the expectation value of relevant quantities. Furthermore, the numerical implementation of probability integrals is shown. The proposed concepts are of general nature and can be taken as a basis for the modeling of similar stochastic processes involving the evolution of the internal microstructure

Numerical simulation of cyclic deformation behavior of SLM‐manufactured aluminum alloys

The selective laser melting process has already been developed for many metallic materials, including steel, aluminum, and titanium. The quasi‐static properties of these materials have been found to be comparable or even better than their conventionally manufactured counterparts. However, for their reliable application in operational components, their fatigue behavior plays a critical role. This phenomenon is dominated by several process‐related features, such as surface roughness, remnant porosity, microstructure and residual stresses. The present contribution shows a model which relies on an assumption for the Helmholtz free energy and the dissipation potential. To be more precise: the phase‐field method is applied to simulate the damage evolution, whereas plastic effects are modeled in terms of the isotropic hardening. It is assumed that the damage evolution only occurs in the tension mode of a cyclic load, which is achieved by the decomposition of the stored energy. The numerical results give insight into the evolution of plastic deformations and of damage at a material point and for a chosen mesoscopic sample

Thermomechanical Modeling of Microstructure Evolution Caused by Strain-Induced Crystallization

The present contribution deals with the thermomechanical modeling of the strain-induced crystallization in unfilled polymers. This phenomenon significantly influences mechanical and thermal properties of polymers and has to be taken into consideration when planning manufacturing processes as well as applications of the final product. In order to simultaneously capture both kinds of effects, the model proposed starts by introducing a triple decomposition of the deformation gradient and furthermore uses thermodynamic framework for material modeling based on the Coleman--Noll procedure and minimum principle of the dissipation potential, which requires suitable assumptions for the Helmholtz free energy and the dissipation potential. The chosen setup yields evolution equations which are able to simulate the formation and the degradation of crystalline regions accompanied by the temperature change during a cyclic tensile test. The boundary value problem corresponding to the described process includes the balance of linear momentum and balance of energy and serves as a basis for the numerical implementation within an FEM code. The~paper closes with the numerical examples showing the microstructure evolution and temperature distribution for different material samples

Numerical simulation of low cycle fatigue behavior, combining the phase-field method and the Armstrong-Frederick model

The present work couples the phase field method of fracture to the Armstrong-Frederick model of plasticity with the kinematic hardening. The chosen approach inherits the advantages of both techniques and is aimed at the study of low cycle fatigue effects in ductile materials. However, the numerical implementation of this promising concept brings with it several challenges, such as the definition of a unique framework for both setups, the derivation of coupled evolution equations, the distinction between tension and compression mode and the development of a computationally efficient algorithm. In the approach developed, the derivation of evolution equations uses the minimum principle of the dissipation potential. This step requires the expression of the dissipation potential of the classic Armstrong-Frederick model in terms of the internal variable rates by using the Legendre transformation. The model is eventually implemented in the FE-program and applied in order to investigate the life-time of the cold-formed carbon steel and the cold-formed stainless steel

On the mechanical modeling of cell components

Eukaryotic cells are complex systems which carry out a variety of different tasks. The current contribution gives insight into the modeling of some of their vital components and represents an overview of results achieved within the international D‐A‐CH project on computational modeling of transport processes in a cell. The first part of the contribution studies viscoelastic effects of cross‐linked actin network embedded in cytosol. The basic‐model is used to simulate the actin behavior at a microscopic level. It considers the influence of the physical length, the end‐to‐end distance and the stretch modulus in order to provide a relationship between the stretch of a single polymer chain and the applied tension force. The effective behavior of the cell cytoplasm is simulated by using the multiscale finite element method. Here, a standard large strain viscous approach is applied for the cytosol, while the generalized Maxwell model simulates viscous effects occurring in filaments due to deviatoric changes. The examples dealing with combinations of tension‐holding tests give insight into the effective behavior of the cytoplasm

Comparison of the visually evoked response in drug-free chronic schizophrenic patients and normal controls

Thirteen cooperative male drug-free chronic schizophrenic patients, and 11 mentally normal male controls were studied. The VER was recorded from scalp leads O1, O2, Oz, C3 and C4 to combined ear reference (A1---A2). The stimulus was an unpatterned flash of single intensity. Compared to normal controls, there were no consistent differences in wave peak latencies or amplitudes for chronic schizophrenics in any brain area tested. When the chronic schizophrenic patients were separated on the basis of high and low tryptophan uptake, using the Frohman-Gottlieb criteria, the high uptake group exhibited normal VERs while in the occipital regions the low tryptophan uptake group exhibited prolonged latencies and an increased amplitude for wave V when compared to normals. From BPRS scores the high tryptophan subgroup indicated a greater degree of psychopathology than the low tryptophan subgroup. The results obtained do not support an indole hallucinogen hypothesis for process schizophrenia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23636/1/0000600.pd

Simulation of cyclic deformation behavior of selective laser melted and hybrid-manufactured aluminum alloys using the phase-field method

Selective laser melting process has already been developed for many metallic materials, including steel, aluminum, and titanium. The quasistatic properties of these materials have been found to be comparable or even better than their conventionally-manufactured counterparts; however, for their reliable applications in operational components, their fatigue behavior plays a critical role, which is dominated by several process-related features, like surface roughness, remnant porosity, microstructure, and residual stresses, which are controlled by the processing features, like imparted energy density to the material, its corresponding solidification behavior, the cooling rate in the process, as well as post-processing treatments. This study investigates the influence of these parameters on the cyclic deformation behavior of selective laser melted as well as hybrid-manufactured aluminum alloys. The corresponding microstructural features and porosity conditions are evaluated for developing correlations between the process conditions to microstructure, the deformation behavior, and the corresponding fatigue lives. From the numerical point of view, damage development with respect to process-induced cyclic deformation behavior is assessed by the phase-field method, which has been identified as an appropriate method for the determination of fatigue life at the respective applied stress levels. Fatigue strength of SLM-processed parts is found better than their cast counterparts, while hybridization has further increased fatigue strength. No effect of test frequency on the fatigue life could be established

Classroom flipped in a virtual platform for the development of competences. Case study: applied research course

The new framework for the quality of higher education proposes to transform the paradigm of didactic intervention, orienting it towards more active mixed methodologies, centered on the student's learning process, incorporating technological tools that allow a better development of the teaching-learning processes. The objective of this study is to apply the Inverted Classroom model through a Moodle virtual platform for the development of research competencies. The study is applied to 46 participants graduated from the professional career of Communication Sciences at the national University of Piura (Peru), where they participated in a professional updating and degree program. The methodology applied is mixed, with quantitative and qualitative data, following a pre-experimental design. To evaluate the competencies, quantitative data were collected at the beginning and end of the Applied Research course. The research hypothesis is to validate whether in the context of the subject of Applied Research in Communication Sciences the pedagogical model Inverted Classroom through the use of the virtual platform Moodle has an effect on the development of research skills in students. The data collection process is carried out at the beginning with a knowledge test applied to the students and at the end with the qualification obtained through an evaluation matrix. The results obtained show significant differences in the average grades of the students, obtained before and after using the Inverted Classroom model, where better results are obtained in the competences referred to the elaboration of the theoretical framework and approach of the studyEl nuevo marco de la calidad de la educación superior propone transformar el paradigma de intervención didáctica orientándolo hacia metodologías mixtas más activas, centradas en el proceso de aprendizaje del estudiante, en el que se incorporan herramientas tecnológicas que permiten un mejor desarrollo de los procesos de enseñanzaaprendizaje. Se realiza un estudio cuyo objetivo es aplicar el modelo Aula Invertida a través de una plataforma virtual Moodle para el desarrollo de competencias investigativas. El estudio es aplicado a 46 participantes egresados de la carrera profesional de Ciencias de la Comunicación de la Universidad nacional de Piura (Perú), donde participaron en un programa de actualización y titulación profesional. La metodología aplicada es mixta, con datos cuantitativos y cualitativos, donde ha seguido un diseño pre experimental. Para evaluar las competencias se recolectan datos cuantitativos al inicio y final del curso de Investigación Aplicada. La hipótesis de investigación consiste en validar si en el contexto de la asignatura de Investigación Aplicada a las Ciencias de la Comunicación si el modelo pedagógico Aula Invertida a través del uso de la plataforma virtual Moodle tiene efecto en el desarrollo de competencias investigativas en los estudiantes. El proceso de recolección de información se realiza al inicio con una prueba de conocimientos aplicada a los estudiantes del y al final con la calificación obtenida a través de una matriz de evaluación. Los resultados obtenidos muestran diferencias significativas en el promedio de calificaciones de los estudiantes, obtenidos antes y después usando el modelo de Aula Invertida, donde se obtienen mejores resultados en las competencias referidas a la elaboración del marco teórico y planteamiento del estudi

Gene methylation biomarkers in sputum as a classifier for lung cancer risk

CT screening for lung cancer reduces mortality, but will cost Medicare ∼2 billion dollars due in part to high false positive rates. Molecular biomarkers could augment current risk stratification used to select smokers for screening. Gene methylation in sputum reflects lung field cancerization that remains in lung cancer patients post-resection. This population was used in conjunction with cancer-free smokers to evaluate classification accuracy of a validated eight-gene methylation panel in sputum for cancer risk. Sputum from resected lung cancer patients (n=487) and smokers from Lovelace (n=1380) and PLuSS (n=718) cohorts was studied for methylation of an 8-gene panel. Area under a receiver operating characteristic curve was calculated to assess the prediction performance in logistic regressions with different sets of variables. The prevalence for methylation of all genes was significantly increased in the ECOG-ACRIN patients compared to cancer-free smokers as evident by elevated odds ratios that ranged from 1.6 to 8.9. The gene methylation panel showed lung cancer prediction accuracy of 82–86% and with addition of clinical variables improved to 87–90%. With sensitivity at 95%, specificity increased from 25% to 54% comparing clinical variables alone to their inclusion with methylation. The addition of methylation biomarkers to clinical variables would reduce false positive screens by ruling out one-third of smokers eligible for CT screening and could increase cancer detection rates through expanding risk assessment criteria