Rapid Performance Evaluation Research Articles

A rapid small scale evaluation of ultrafiltration performance for surface water treatment at Alcantarilha's water treatment works (Algarve, Portugal)

A rapid small-scale evaluation of ultrafiltration (UF) performance with and without physical–chemical pre-treatment was performed to up-grade the conventional treatment used for drinking water production in Alcantarilha's water treatment works, Algarve, Portugal. Direct UF and pre-ozonation/coagulation/flocculation/sedimentation/UF (O/C/F/S/UF) were evaluated using polysulphone membranes of different apparent molecular weight cut-off (MWCO) (15–47 kDa). The results indicated that (i) UF is an effective barrier against microorganisms, including virus larger than 80 nm; (ii) for surface waters with low to moderate SUVA values, direct UF performance is equivalent or better than the conventional treatment in terms of residual turbidity, while UV254 nm and TOC residuals require the use of O/C/F/S/UF; (iii) the permeate quality improves with the membrane apparent MWCO decrease, especially for the direct UF, although the conventional treatment performance is never reached using UF; (iv) membrane fouling and adsorption phenomena are more severe in direct UF than in O/C/F/S/UF sequence (pre-ozonation decreases the membrane foulants by decreasing their hydrophobicity) and these phenomena increase with the membrane hydraulic permeability and, particularly, with the membrane apparent MWCO.

Tissue doppler imaging predicts improved systolic performance and reversed left ventricular remodeling during long-term cardiac resynchronization therapy

ObjectivesWe sought to evaluate the long-term impact of cardiac resynchronization therapy (CRT) on left ventricular (LV) performance and remodeling using three-dimensional echocardiography and tissue Doppler imaging (TDI). BackgroundThree-dimensional echocardiography and TDI allow rapid and accurate evaluation of LV volumes and performance. MethodsTwenty-five consecutive patients with severe heart failure and bundle branch block who underwent biventricular pacemaker implantation were included. Before and after implantation of the pacemaker, three-dimensional echocardiography and TDI were performed. These examinations were repeated at outpatient visits every six months. ResultsFive patients (20%) died during one-year follow-up. In the remaining 20 patients, significant reductions in LV end-diastolic volume and LV end-systolic volume of 9.6 ± 14% and 16.5 ± 15%, respectively (p < 0.01), could be demonstrated during long-term follow-up. Accordingly, LV ejection fraction increased by 21.7 ± 18% (p < 0.01). According to a newly developed TDI technique—tissue tracking—all regional myocardial segments improved their longitudinal systolic shortening (p < 0.01). The extent of the LV base displaying delayed longitudinal contraction, as detected by TDI before pacemaker implantation, predicted long-term efficacy of CRT. The QRS duration failed to predict resynchronization efficacy. ConclusionsCardiac resynchronization significantly improved LV function and reversed LV remodeling during long-term follow-up. Patients likely to benefit from CRT can be identified by TDI before implantation of a biventricular pacemaker.

Rapid Performance Evaluation and Optimal Sizing of Dry Cyclone Separators

Cyclones are generally less efficient than other kinds of equipment, but their simple construction, low energy requirements, and ability to operate at high temperatures and pressures make them attractive for cleaning up gases. Despite the simplicity in construction and operation, complex mathematical formulations are used for predicting the collection efficiency of particles of a given diameter. These must be numerically integrated, along with the inlet particle-size-distribution functions that are appropriate in each application, in order to obtain the overall cyclone efficiency. In this paper, the above cumbersome procedure is simplified through nomographs allowing rapid, yet rigorous, estimation of the overall cyclone efficiencies based on two alternative and well-established approaches and on the sole assumption of a lognormal particle-size distribution. Along with the above, pressure drop and limiting inlet velocity correlations are also considered, and each of the above nomographs is combined with others, providing direct graphical representation of the so far obscure relationships among cyclone diameter, overall efficiency, and gas pressure drop or flow rate. The paper thus affords an overview of cyclone behavior over a wide range of conditions, offering direct solutions to both cyclone performance and optimal cyclone design problems.

IGBT Package Design for High Power Aircraft Electronic Systems

This paper will discuss the design of semiconductor packages having integrated air cooled heatsinks for use in high power electronic systems. It will demonstrate how simple models of the heat transfer from the heatsink fins, which are based on empirical correlations, may be utilized in combination with either simple analytical models or two-dimensional finite difference (FD) models of the heat conduction from the semiconductor die through the multilayer package structure to the base of the fins. These models allow the rapid evaluation of performance under both steady-state and transient overload conditions, and can be used to rapidly explore a wide range of design options before selecting candidate layouts for more detailed evaluation using 3D analysis tools. Wind tunnel experiments, which will also be reported, have been carried out to verify the modeling results for different semiconductor device layouts. These trials demonstrate excellent agreement between the models and experimental results.

A new approach to BER estimation for ISI corrupted baseband transmission systems

AbstractThis paper derives two new formulae for BER estimation when the transmission system is subject to both intersymbol interference and additive Gaussian noise. The approach undertaken here was oriented to find a simple formula giving close estimation of the true BER, which may be useful for the transmission system designer for rapid evaluation of system performance. The obtained results are compared with commonly used BER estimations. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Fundamental Bit-Error-Rate Limits of In-Line Optical Regeneration by Synchronous Intensity Modulation: An Analytical Gaussian-Statistics Model

Fundamental limits of optical regeneration by in-line synchronous intensity modulation are evaluated through a simple Gaussian-statistics analysis. Regeneration is shown to involve three processes: asymptotic stabilization of signal-to-noise ratio, asymptotic stabilization of timing jitter, and instrinsic conversion of timing jitter into intensity noise. The model also includes filtering, which is shown to reduce or suppress amplitude noise. Key system parameters, which are valid regardless the origin of noise and jitter (amplification, interaction, collisions), are identified for the regime of “infinite” transmission, where the bit-error rate becomes distance-invariant. These parameters make it possible to predict the level and distance at which the bit-error rate converges, thus enabling rapid analytical evaluation and optimization of system performance. Novel effects such as transition from intensity-noise-limited to timing-jitter-limited regimes (or the reverse) and eye reopening with distance have been identified and analyzed for the first time.

A Grinding Map Concept for Optimization of Ceramic Machining

This paper describes a systematic attempt to isolate various parameters that affect the material removal rate for diamond grinding of silicon nitride ceramics. The influence of different coolants and operating parameters such as force, depth of cut, and diamond grit size on the material removal rates under controlled conditions of single pass grinding is determined. Several parameters were developed to aid in interpretation of the grinding results. The parameters include grinding force coefficient, retained grinding efficiency, and instantaneous grinding rate. A grinding map concept was developed to allow rapid visual evaluation of grinding performance for a given coolant and a set of operating conditions. The results suggest that material removal rates in grinding of silicon nitride ceramics can be increased through optimization of machining parameters and the proper use of suitable coolants. The major contribution to decreased grinding rates for silicon nitride machining in these tests was due to dulling of the diamond abrasive embedded in the grinding wheel. Significant coolant chemistry effects were observed as it affects the diamond dulling rate due to oxidative wear mechanisms.

Performance analysis of a cardiac assist device in counterpulsation.

Performance of a cardiac assist device pumping chamber in counterpulsation was evaluated using numerical simulations of the unsteady, three-dimensional flow inside the chamber and an analytical model of the force required to eject and fill the chamber. The wall shear stress within the device was similarly computed and modeled. The analytical model was scaled to match the numerical results and then used to predict performance at physiological operating conditions. According to these models for a stroke volume of 70 ml, between 0.4 and 1.0 W is required for counterpulsation at a frequency of 1.33 Hz against a restorative spring, depending on the spring constant chosen. The power and the maximum force calculated are within the ranges a trained skeletal muscle is capable of providing. Shear stress predictions show that platelet activation in the absence of surface effects and hemolysis due to high shear are unlikely to occur with this design. Furthermore, vortices that develop in the chamber during filling are predicted to increase blood mixing and provide favorable washing of the chamber walls. A computational-analytical approach such as this may have potential to aid rapid performance evaluation of new devices and streamline the design optimization process.

Rapid Sizing and Performance Evaluation of Submarine Outfalls with Line Diffusers

Based on limited available data, engineers are often called upon to prepare preliminary designs of new outfalls or to screen the performance of existing ones in the context of developing rational management schemes for urban and/or industrial effluents. In view of this need, our objective is to develop a simplified procedure, able to provide guidance with minimal field information and capable of utilizing any relevant marine survey data that may exist for enhancing the accuracy of predictions. For achieving the previous objective, the relations for all three dilution mechanisms are considered simultaneously, so as to have their combined impact analyzed. A set of baseline conditions is defined by assigning typical and typical-adverse values to selected input variables. Sensitivity analysis is performed, helping to further simplify the problem. The simplified model is analyzed in terms of its functional dependencies, and nomograms are developed, offering a convenient solution of the baseline problem. This baseline solution is easily adapted to local conditions through a correction multiplier factor computed on the basis of actual marine survey data that may exist.

A framework for the exact evaluation of expected cycle times in automated storage systems with full-turnover item allocation and random service requests

We present a new framework for obtaining analytic expressions of the expected throughput rate in Automated Storage and Retrieval Systems (AS/RSs). The models developed consider generalized full-turnover item allocation policies and random storage and retrieval requests. Both single command and dual command operations are considered. A general expression for the expected cycle time in a single command class-based system is also developed. It is shown that some well known results are derived as special cases of our expression. These results provide for rapid performance evaluation of various operational policies in automated warehouses and in certain mass-storage information devices currently used by various computer systems. The potential for significant reductions in the expected cycle time is demonstrated in the case of full-turnover item allocation.

Optimization of the Gel Electrode for Repeatable Imaging of Fatigue Cracks in Aluminum Alloys

Abstract The gel electrode method of detecting and imaging very small fatigue cracks in aluminum alloys provides the basis for a more rapid evaluation of fatigue performance and offers the convenience of periodic inspections during a test to monitor the initiation and growth of cracks. However, repetitive imaging of fatigue cracks can yield images with successively weaker contrast. This problem can be avoided by the correct selection of the operating parameters. This report describes the influence of various parameters on the spatial resolution and repeatability of the image. The spatial resolution is increased by increasing the starch concentration and reducing the charge flow. To obtain repeatable images the pulse duration (and charge) must be adjusted to balance the effects of the processes of passivation and corrosion. Sodium borate, which was previously included as an electrochemical buffer, should be omitted because it promotes too much passivation. Increasing the concentration of potassium iodide deters passivation so that images can be obtained repeatably with a shorter voltage pulse, less charge, and better spatial resolution. A compromise must be made between the spatial resolution and the visibility of the image. For routine inspection of components a highly visible image can be obtained with a gel electrode containing 0.06 M potassium iodide (KI) and 0.2 M starch upon application of a 10 V, 50 ms pulse. This combination yields repeatable images of cracks in aluminum alloys, with a spatial resolution ≈ 6 × 10−2 mm.

Rapid Design and Performance Evaluation of Steady-State Journal Bearings—A Technique Amenable to Programmable Hand Calculators

A simple technique for the rapid design and performance evaluation of steady-state journal bearings is presented. The technique which is amenable to hand calculator use is compared with a numerical solution for all relevant design parameters. Results indicate that the bearing designer may utilize the technique over a wide range of (L/D) and eccentricity ratios without serious error. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in New Orleans, Louisiana, October 5–7, 1981

Multiple-Frequency Operation of Y-Junction Circulators Using Single-Mode Approximation

The conditions for a Y-junction circulator to operate within more than one frequency band are studied. By taking into account only the dominant resonance mode at each circulation frequency, explicit expressions are obtained which define the properties of the circulator. The results are presented in diagrams and tables which enable rapid evaluation of obtainable performance for some of the most important mode combinations. The validity of the results are experimentally verified.

Rapid evaluation of magnetic filter performance

Theory of homogeneous filter is developed. Results are employed to analyze tests made with SS430 fiber metal or stainless steel wool matrices. As regards filter efficiency, the experiments seem to disagree with particle trajectory models quantitatively but show agreement with the creeping flow model qualitatively. The method used is extended from laboratory to field experiments.

Design and performance of a programmable real-time charge-coupled-device recirculating delay-line correlator

The design and performance of a recirculating delay-line correlator employing a charge-coupleddevice high-density digital memory are reported. The operation of the processor is demonstrated when arranged as a matched filter and spectrum analyser for typical sonar waveforms. The processor permits rapid evaluation of system performance with changes in signal parameters, and resutls are presented which simulatethe effects of target Doppler on linear frequency modulation and linear period modulation

Evaluation of a Management Development Methodology.

This research examines a methodology for evaluating management development efforts. The design incorporates three principal evaluation configurations. A comprehensive pre- and post-test paper-and-pencil evaluation is used to measure overall learning. The second evaluation mode utilizes a repeatable testing procedure that is incorporated as part of the in-class development effort. The last measure is the trainee evaluation of the course organization, content and instruction. A second objective was to apply Personalized System of Instruction techniques to a management development program. Program content consisted of advanced personnel management application. Those Personalized System of Instruction techniques applied consisted of basic objectives, repeatable testing, rapid performance evaluation feedback for trainees, and mastery learning.

A Computer Aided Function Allocation and Evaluation System (CAFES)

The Computer Aided Function Allocation and Evaluation System (CAFES) is a crew systems design support tool based on human engineering methodology, computer aids, human performance data and a data management system. It is intended to support crew systems engineers in man-machine research, requirements analysis, design, test, training and maintenance systems development. The system of computer models comprising the CAFES system parallels the system development cycle and provides the required level of detail consistent with a given stage of system development. The principle objectives of the present development program are to facilitate timely application of all essential elements of human factors technology in systems development, using automatic data processing techniques for rapid analysis and evaluation of crew subsystem performance as it effects total systems effectiveness.

Retroreflective Photometry for Screen Efficiency Evaluation

An analytical treatment is given which shows that the peak luminance gain and lobe width of a back or front projection screen material can be used as coordinates on a graph to determine the transmission or reflection efficiency. The analysis assumes that the angular distribution of the gain can be expressed as a power of a cosine function. Also, a screen photometer is described which is based upon the adaptation of a spectrometer to measure screens having retroreflective characteristics. The photometer is capable of measuring luminance on the retroreflective axis and out to 15 degrees on either side of the incident beam. Screen samples, 2.54 cm sq, can be oriented through angles of +/-30 degrees to the incident beam and luminances from 1 ft-L to 10,000 f t-L (from about 3.5 cd/m(2) to 35,000 cd/m(2)) can be handled. The instrument has three modes of operation: visual, photoelectric, and photographic. A graph is presented illustrating the application of the analytical technique to provide a rapid performance evaluation and comparison of screen efficiencies.

Surface and Corrosion Characteristics of Tin‐Free Steel—Chromium Type for Beverage Containers

The new tin‐free steel‐chromium type (TFS‐CT) materials are described which constitute a new generation of tin‐free materials for can making. The steel is electroplated with a very thin film of metallic chromium approximately in. thick which is covered by a thin layer of chromium oxide. Processes for producing TFS‐CT are reviewed and the relative amounts of metallic chromium and chromium oxide are indicated for the products now available commercially. Performance requirements, bench tests for rapid evaluation of performance, and analytical techniques for measuring the amounts of chromium in the metallic and oxide layers are described. Results of electrochemical, and corrosion tests are reported which indicate the relative importance of the metallic chromium and chromium oxide layers as they affect corrosion resistance.

Plug nozzle engine

The efficient and accurate access to the aerodynamic performance is important for the design and optimization of supercritical airfoils. The aerodynamic performance is usually obtained by using computational fluid dynamics (CFD) methods or wind-tunnel experiments. But the computations of CFD are very time intensive and expensive, and the prior knowledge in wind-tunnel experiments plays a decisive role in engineering. Though many surrogate methods were proposed to alleviate the costs of these traditional approaches, most of them can only calculate the low-dimensional aerodynamic performance, and is not able to provide the accurate prediction of transonic flow fields for supercritical airfoils. Since the flow fields are equipped with its own discipline as a physical system in fluid dynamics, it is therefore possible to learn this discipline via data-driven machine learning approaches. Deep learning is witness to expansive growth into diverse applications due to its immense ability to extract essential features from complicated physical systems. Generative adversarial networks (GANs) as a recent popular method in deep leaning are capable of efficiently capturing the distribution of training data. In this work, we proposed a surrogate model, ffsGAN, which leverage the property of GANs combined with convolution neural networks (CNNs) to directly establish a one-to-one mapping from a parameterized supercritical airfoil to its corresponding transonic flow field profile over the parametric space. Compared with the most existing surrogate models, the ffsGAN is superior in efficiently and accurately predicting the high-dimensional flow field rather than the low-dimensional aerodynamic characteristics. The ffsGAN method is first trained using 500 airfoils that sampled based on RAE2822. The flow fields are then predicted for unseen airfoils to evaluate the generalization of the model in terms of prediction accuracy. An investigation of the effects of various hyper-parameters in the network architectures and loss functions is performed. The experimental results show that ffsGAN is a promising tool for rapid evaluation of detailed aerodynamic performance. The elaborate flow field predicted by ffsGAN is possible to be considered in airfoil design to further improve the design and optimization quality in the future.