A scalable parallel finite element framework for growing geometries. Application to metal additive manufacturing

This work introduces an innovative parallel, fully-distributed finite element framework for growing geometries and its application to metal additive manufacturing. It is well-known that virtual part design and qualification in additive manufacturing requires highly-accurate multiscale and multiphysics analyses. Only high performance computing tools are able to handle such complexity in time frames compatible with time-to-market. However, efficiency, without loss of accuracy, has rarely held the centre stage in the numerical community. Here, in contrast, the framework is designed to adequately exploit the resources of high-end distributed-memory machines. It is grounded on three building blocks: (1) Hierarchical adaptive mesh refinement with octree-based meshes; (2) a parallel strategy to model the growth of the geometry; (3) state-of-the-art parallel iterative linear solvers. Computational experiments consider the heat transfer analysis at the part scale of the printing process by powder-bed technologies. After verification against a 3D benchmark, a strong-scaling analysis assesses performance and identifies major sources of parallel overhead. A third numerical example examines the efficiency and robustness of (2) in a curved 3D shape. Unprecedented parallelism and scalability were achieved in this work. Hence, this framework contributes to take on higher complexity and/or accuracy, not only of part-scale simulations of metal or polymer additive manufacturing, but also in welding, sedimentation, atherosclerosis, or any other physical problem where the physical domain of interest grows in time

Recombinant alpha-interferon as salvage therapy in multiple myeloma

Ten patients with end-stage multiple myeloma refractory to conventional chemotherapy and hemibody irradiation received recombinant α-interferon as salvage therapy. The median duration of treatment was 8 weeks. One patient had an objective response and survived 8 months, whereas in the remaining 9 patients the disease progressed and median survival was 11,5 weeks. Side-effects were substantial and included confusion with extreme weakness, resulting in 5 patients refusing further therapy. The low response rate and the morbidity in this pilot study resulted in its discontinuation and the conclusion that recombinant α-interferon as singleagent therapy used for salvage in patients with refractory myeloma is of no value.S Afr Med J 1989; 76: 100-10

Dressed-band approach and Coulomb corrections to the light-induced exciton Stark shift

In the present work, we perform a comparison of theoretical approaches involving Coulomb-interaction corrections within the Hartree-Fock approximation and the renormalized dressed-band scheme in the large detuning limit. We focus on the well-studied optical Stark shift of the exciton peak in bulk and GaAs-(Ga,Al)As semiconductor quantum wells. It is argued that the Hartree-Fock scheme has severe limitations concerning its application to real experimental situations, even in the simplest laser field-perturbative regime. It is also shown, through a comparison between experiments and a three-band Kane-dressed GaAs-(Ga,Al)As quantum well calculation, that a proper treatment of band structure and confinement effects due to the quantum well is of fundamental importance in a theoretical understanding of Stark shift experimental measurements, and that the renormalized dressed-band approach is a very convenient tool to treat, in the large detuning limit, processes involving the laser-semiconductor interaction in low-dimensional heterostructures. (C) 2003 American Institute of Physics.9495742574

Rabi oscillations, coherent properties, and model qubits in two-level donor systems under terahertz radiation

Quantum confinement, magnetic-field effects, and laser coupling with the two low-lying states of electrons bound to donor impurities in semiconductors may be used to coherently manipulate the two-level donor system in order to establish the appropriate operational conditions of basic quantum bits (qubits) for solid-state based quantum computers. Here we present a theoretical calculation of the damped Rabi oscillations and time evolution of the 1s and 2p(+) donor states in bulk GaAs under an external magnetic field and in the presence of terahertz laser radiation, and their influence on the measured photocurrent. We also discuss the possible experimental conditions under which decoherence is weak and qubit operations are efficiently controlled.682

A hybrid constructed wetland for organic-material and nutrient removal from sewage: Process performance and multi-kinetic models

© 2018 Elsevier Ltd A pilot-scale hybrid constructed wetland with vertical flow and horizontal flow in series was constructed and used to investigate organic material and nutrient removal rate constants for wastewater treatment and establish a practical predictive model for use. For this purpose, the performance of multiple parameters was statistically evaluated during the process and predictive models were suggested. The measurement of the kinetic rate constant was based on the use of the first-order derivation and Monod kinetic derivation (Monod) paired with a plug flow reactor (PFR) and a continuously stirred tank reactor (CSTR). Both the Lindeman, Merenda, and Gold (LMG) analysis and Bayesian model averaging (BMA) method were employed for identifying the relative importance of variables and their optimal multiple regression (MR). The results showed that the first-order–PFR (M2) model did not fit the data (P > 0.05, and R2 0.5). The pollutant removal rates in the case of M1 were 0.19 m/d (CODCr) and those for M3 were 25.2 g/m2∙d for CODCr and 2.63 g/m2∙d for NH4-N. By applying a multi-variable linear regression method, the optimal empirical models were established for predicting the final effluent concentration of five days' biochemical oxygen demand (BOD5) and NH4-N. In general, the hydraulic loading rate was considered an important variable having a high value of relative importance, which appeared in all the optimal predictive models

Enhanced efficiency for better wastewater sludge hydrolysis conversion through ultrasonic hydrolytic pretreatment

© 2016 Taiwan Institute of Chemical Engineers The major requirements for accelerating the process of anaerobic digestion and energy production are breaking the structure of waste activated sludge (WAS), and transforming it into a soluble form suitable for biodegradation. This work investigated and analysed a novel bench-scale ultrasonic system for WAS disruption and hydrolysis using ultrasonic homogenization. Different commercial sonoreactors were used at low frequencies under a variety of operating conditions (intensity, density, power, sonication time, and total suspended solids) to evaluate the effects of the equipment on sludge hydrolysis and to generate new insights into the empirical models and mechanisms applicable to the real-world processing of wastewater sludge. A relationship was established between the operating parameters and the experimental data. Results indicated an increase in sonication time or ultrasonic intensity correlated with improved sludge hydrolysis rates, sludge temperature, and reduction rate of volatile solids (33.51%). It also emerged that ultrasonication could effectively accelerate WAS hydrolysis to achieve disintegration within 5–10 min, depending on the ultrasonic intensity. This study also determined multiple alternative parameters to increase the efficiency of sludge treatment and organic matter reduction, and establish the practicality of applying ultrasonics to wastewater sludge pretreatment

Selecting Display Products for Furniture Stores Using Fuzzy Multi-criteria Decision Making Techniques

© 2018, Springer Nature Switzerland AG. Efficient marketing in which the right products are supplied to the right consumer plays a crucial role for a profitable business in the age of highly accessible and competitive global market. This fact enforces producers to clearly identify and analyze the needs of consumers and to display their products respecting locality based on customers’ needs. The position of the business is strengthened within the market and its competiveness increases by supplying and displaying the products suitable to regional consumers’ preferences. In this study, an integral fuzzy multi criteria decision making technique is proposed for an effective decision making process to select the most suitable display products to the consumers’ needs and preferences. The approach has been applied to identify the most suitable set of modular furniture products to be displayed at a local store that locates in Bursa city of Turkey. The approach uses Fuzzy DEMATEL method to work out the interrelations of chosen criteria, which are weighted with Fuzzy ANP and finally suggest a rank-based list of products with Fuzzy PROMETHEE. The results are verified with the expert view and found very useful

Comparison of Hospital Costs and Length of Stay for Community Internists, Hospitalists, and Academicians

BACKGROUND: The model of inpatient medical management has evolved toward Hospitalists because of greater cost efficiency compared to traditional practice. The optimal model of inpatient care is not known. OBJECTIVE: To compare three models of inpatient Internal Medicine (traditional private practice Internists, private Hospitalist Internists, and Academic Internists with resident teams) for cost efficiency and quality at a community teaching hospital. DESIGN: Single-institution retrospective cohort study. MEASUREMENTS AND MAIN RESULTS: Measurements were hospital cost, length of stay (LOS), mortality, and 30-day readmission rate adjusted for severity, demographics, and case mix. Academic Internist teams had 30% lower cost and 40% lower LOS compared to traditional private Internists and 24% lower cost and 30% lower LOS compared to private Hospitalists. Hospital mortality was equivalent for all groups. Academic teams had 2.3–2.6% more 30-day readmissions than the other groups. CONCLUSIONS: Academic teams compare favorably to private Hospitalists and traditional Internists for hospital cost efficiency and quality