A Theoretical Approach in the Design of Single Frame 28 V DC and 270 V DC Dual Voltage Generator

Armored Fighting Vehicles (AFVs) generally operate with a 28 V DC electrical system. However, the demand for electrical power in AFVs has exceeded the capabilities of the existing 28V system. The additional load growth necessitates larger wire sizes, which adds extra weight and cost to the vehicle. Introducing a dual-bus architecture (28 V DC and 270 V DC) can lead to the efficient operation of the electrical system while meeting future demand. This paper presents the design of a Brushless Direct Current (BLDC) Dual Voltage Generator (DVG), which simultaneously outputs two voltages (28 V DC & 270 V DC) from a single frame across a wide operational speed range. The design process includes a detailed description of the individual stages, accompanied by analytical parameters and software-generated results. The modeling and analysis of the generator were carried out using Motorsolve design software. The obtained results are presented and thoroughly discussed in this paper

A taxonomy of parallel sorting

TR 84-601In this paper, we propose a taxonomy of parallel sorting that includes a broad range of array and file sorting algorithms. We analyze the evolution of research on parallel sorting, from the earliest sorting networks to the shared memory algorithms and the VLSI sorters. In the context of sorting networks, we describe two fundamental parallel merging schemes - the odd-even and the bitonic merge. Sorting algorithms have been derived from these merging algorithms for parallel computers where processors communicate through interconnection networks such as the perfect shuffle, the mesh and a number of other sparse networks. After describing the network sorting algorithms, we show that, with a shared memory model of parallel computation, faster algorithms have been derived from parallel enumeration sorting schemes, where keys are first ranked and then rearranged according to their rank

Eye of horus – Erratum revealed a prescription survey

Background: The aim of this study was to survey the quality and the content of prescription of practitioners and also assess the legibility of alphabet, and short form of the drug.Methods: A survey of all prescription received by the patients that were written by general practitioners, consulting physicians and dentists in and around Virajpet and Madikeri (south Coorg) was included.The prescriptions were photocopied and returned back to the patients. The prescription was scored and analyzed by a qualified medical investigator.Results: A total of 171 prescription samples were collected. In most prescriptions, one or more aspects of patient’s personal details were missing. Concerned doctor’s details also lacked in most cases. 40.3% of the prescriptions were obtained wherein short form of the drug was used for prescribing drug. Legibility of alphabet was also evaluated and the most confusing letter noted in our study was letter “C”; followed by A, T, S, O, G, and D in this study the letter Rx was written in 7% of the prescription and in 19% prescription it was replaced by word “Adv” and 74% of prescription without symbol of Rx.Conclusions: The present data shows most prescriptions in the study was inadequate and important details were lacking, legibility of prescription was poor in rating

Understanding the customer base of service providers: An examination of the differences between switchers and stayers

Creating and maintaining customer loyalty has become a strategic mandate in today\u27s service markets. Recent research suggests that customers differ in their value to a firm, and therefore customer retention and loyalty-building efforts should not necessarily be targeted to all customers of a firm. Given these sentiments, it is becoming increasingly necessary for firms to have a thorough understanding of their customer base. Yet current knowledge is limited in providing insights to firms regarding the differences within their customer base. This research comprises two studies in which the authors examine the differences among internal customer groups in a service industry. As theory suggests and as is empirically validated here, customers who have switched service providers because of dissatisfaction seem to differ significantly from other customer groups in their satisfaction and loyalty behaviors, The findings offer some interesting implications for both marketing theory and practice

Predicting Hemiwicking Dynamics on Textured Substrates

The ability to predict liquid transport rates on textured surfaces is key to the design and optimization of devices and processes such as oil recovery, coatings, reaction-separation, high-throughput screening, and thermal management. In this work we develop a fully analytical model to predict the propagation coefficients for liquids hemiwicking through micropillar arrays. This is carried out by balancing the capillary driving force and a viscous resistive force and solving the Navier–Stokes equation for representative channels. The model is validated against a large data set of experimental hemiwicking coefficients harvested from the literature and measured in-house using high-speed imaging. The theoretical predictions show excellent agreement with the measured values and improved accuracy compared to previously proposed models. Furthermore, using lattice Boltzmann (LB) simulations, we demonstrate that the present model is applicable over a broad range of geometries. The scaling of velocity with texture geometry, implicit in our model, is compared against experimental data, where good agreement is observed for most practical systems. The analytical expression presented here offers a tool for developing design guidelines for surface chemistry and microstructure selection for liquid propagation on textured surfaces

Extensional flow of hyaluronic acid solutions in an optimized micofluidic cross-slot device

We utilize a recently developed microfluidic device, the Optimized Shape Cross-slot Extensional Rheometer (OSCER), to study the elongational flow behavior and rheological properties of hyaluronic acid (HA) solutions representative of the synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation point device that imposes a planar extensional flow with a homogenous extension rate over a significant length of the inlet and outlet channel axes. Due to the compressive nature of the flow generated along the inlet channels, and the planar elongational flow along the outlet channels, the flow field in the OSCER device can also be considered as representative of the flow field that arises between compressing articular cartilage layers of the knee joints during running or jumping movements. Full-field birefringence microscopy measurements demonstrate a high degree of localized macromolecular orientation along streamlines passing close to the stagnation point of the OSCER device, while micro-particle image velocimetry is used to quantify the flow kinematics. The stress-optical rule is used to assess the local extensional viscosity in the elongating fluid elements as a function of the measured deformation rate. The large limiting values of the dimensionless Trouton ratio, Tr ∼ O(50), demonstrate that these fluids are highly extensional-thickening, providing a clear mechanism for the load-dampening properties of SF. The results also indicate the potential for utilizing the OSCER in screening of physiological SF samples, which will lead to improved understanding of, and therapies for, disease progression in arthritis sufferers

Metal-coordination: using one of nature's tricks to control soft material mechanics

Growing evidence supports a critical role of dynamic metal-coordination crosslinking in soft biological material properties such as self-healing and underwater adhesion. Using bio-inspired metal-coordinating polymers, initial efforts to mimic these properties have shown promise. Here we demonstrate how bio-inspired aqueous polymer network mechanics can be easily controlled via metal-coordination crosslink dynamics; metal ion-based crosslink stability control allows aqueous polymer network relaxation times to be finely tuned over several orders of magnitude. In addition to further biological material insights, our demonstration of this compositional scaling mechanism should provide inspiration for new polymer material property-control designs.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (DMR-0820054)Danish Council for Independent Research (Natural Sciences for a Post-Doctoral Fellowship 272-08-0087)University of Chicago. Materials Research Science and Engineering Center (DMR 0820054

Structure-Based Optimization of Covalent, Small-Molecule Stabilizers of the 14-3-3σ/ERα Protein-Protein Interaction from Nonselective Fragments

The stabilization of protein-protein interactions (PPIs) has emerged as a promising strategy in chemical biology and drug discovery. The identification of suitable starting points for stabilizing native PPIs and their subsequent elaboration into selective and potent molecular glues lacks structure-guided optimization strategies. We have previously identified a disulfide fragment that stabilized the hub protein 14-3-3σ bound to several of its clients, including ERα and C-RAF. Here, we show the structure-based optimization of the nonselective fragment toward selective and highly potent small-molecule stabilizers of the 14-3-3σ/ERα complex. The more elaborated molecular glues, for example, show no stabilization of 14-3-3σ/C-RAF up to 150 μM compound. Orthogonal biophysical assays, including mass spectrometry and fluorescence anisotropy, were used to establish structure-activity relationships. The binding modes of 37 compounds were elucidated with X-ray crystallography, which further assisted the concomitant structure-guided optimization. By targeting specific amino acids in the 14-3-3σ/ERα interface and locking the conformation with a spirocycle, the optimized covalent stabilizer 181 achieved potency, cooperativity, and selectivity similar to the natural product Fusicoccin-A. This case study showcases the value of addressing the structure, kinetics, and cooperativity for molecular glue development. </p

A fractional K-BKZ constitutive formulation for describing the nonlinear rheology of multiscale complex fluids

The relaxation processes of a wide variety of soft materials frequently contain one or more broad regions of power-law like or stretched exponential relaxation in time and frequency. Fractional constitutive equations have been shown to be excellent models for capturing the linear viscoelastic behavior of such materials, and their relaxation modulus can be quantitatively described very generally in terms of a Mittag–Leffler function. However, these fractional constitutive models cannot describe the nonlinear behavior of such power-law materials. We use the example of Xanthan gum to show how predictions of nonlinear viscometric properties, such as shear-thinning in the viscosity and in the first normal stress coefficient, can be quantitatively described in terms a nonlinear fractional constitutive model. We adopt an integral K-BKZ framework and suitably modify it for power-law materials exhibiting Mittag–Leffler type relaxation dynamics at small strains. Only one additional parameter is needed to predict nonlinear rheology, which is introduced through an experimentally measured damping function. Empirical rules such as the Cox–Merz rule and Gleissle mirror relations are frequently used to estimate the nonlinear response of complex fluids from linear rheological data. We use the fractional model framework to assess the performance of such heuristic rules and quantify the systematic offsets, or shift factors, that can be observed between experimental data and the predicted nonlinear response. We also demonstrate how an appropriate choice of fractional constitutive model and damping function results in a nonlinear viscoelastic constitutive model that predicts a flow curve identical to the elastic Herschel-Bulkley model. This new constitutive equation satisfies the Rutgers-Delaware rule, which is appropriate for yielding materials. This K-BKZ framework can be used to generate canonical three-element mechanical models that provide nonlinear viscoelastic generalizations of other empirical inelastic models such as the Cross model. In addition to describing nonlinear viscometric responses, we are also able to provide accurate expressions for the linear viscoelastic behavior of complex materials that exhibit strongly shear-thinning Cross-type or Carreau-type flow curves. The findings in this work provide a coherent and quantitative way of translating between the linear and nonlinear rheology of multiscale materials, using a constitutive modeling approach that involves only a few material parameters