Impact Of Design Parameters Research Articles

A nanofilter for fluidic devices by pillar-assisted self-assembly microparticles.

We present a nanofilter based on pillar-assisted self-assembly microparticles for efficient capture of bacteria. Under an optimized condition, we simply fill the arrays of microscale pillars with submicron scale polystyrene particles to create a filter with nanoscale pore diameter in the range of 308 nm. The design parameters such as the pillar diameter and the inter-pillar spacing in the range of 5 μm-40 μm are optimized using a multi-physics finite element analysis and computational study based on bi-directionally coupled laminar flow and particle tracking solvers. The underlying dynamics of microparticles accumulation in the pillar array region are thoroughly investigated by studying the pillar wall shear stress and the filter pore diameter. The impact of design parameters on the device characteristics such as microparticles entrapment efficiency, pressure drop, and inter-pillar flow velocity is studied. We confirm a bell-curve trend in the capture efficiency versus inter-pillar spacing. Accordingly, the 10 μm inter-pillar spacing offers the highest capture capability (58.8%), with a decreasing entrapping trend for devices with larger inter-pillar spacing. This is the case that the 5 μm inter-pillar spacing demonstrates the highest pillar wall shear stress limiting its entrapping efficiency. As a proof of concept, fluorescently labeled Escherichia coli bacteria (E. coli) were captured using the proposed device. This device provides a simple design, robust operation, and ease of use. All of which are essential attributes for point of care devices.

Design parameters impact on output characteristics of flexible hybrid energy harvesting generator: Experimental and theoretical simulation based on a parallel hybrid model

The impact of design and external parameters on the intrinsic output properties and load characteristics of hybrid energy harvesting generator is significant in both designing the generator and power management circuit and achieving high energy conversion efficiency. In this work, the intrinsic output characteristics of a hybrid triboelectric and piezoelectric generator is investigated, where the impacts of design parameters on the output properties and load characteristics under resistive and capacitive load conditions are demonstrated using a wide-ranging setting of the design parameters and compared with the theoretical calculations using a parallel hybrid model. The regularities concluded from the experimental results reflect the actual output behavior of a typical hybrid generator and provide evidence that the parameters have significant impacts on the intrinsic output properties, resistive load behavior and charging behavior. The outcomes of this study can be used as guidance toward designing effective structures and power management as well as in future simulation of a wide range of hybrid generators.

The Impact of Urban Design Descriptors on Outdoor Thermal Environment: A Literature Review

This paper presents a literature review on urban design indicators addressing the impact of urban geometry and vegetation on the outdoor thermal environment at the pedestrian level, as urban geometry and vegetation have been regarded as the most influential urban design factors that affect outdoor microclimate. The thermal balance concept is first introduced to elaborate how each component of energy fluxes is affected by the urban built environment, which helps to explore the underlying thermophysical mechanisms of how urban design modifies the outdoor thermal environment. The literature on numerous urban design descriptors addressing urban geometric characteristics is categorized into five groups in this paper according to the design features that the parameters entail, including land use intensity, building form, canyon geometry, space enclosure and descriptive characteristics. The literature on urban vegetation descriptors is reviewed together, followed by the combined effect of urban geometry and vegetation. This paper identifies a series of important urban design parameters and shows that the impact of design parameters on thermal environment varies with time, season, local climate and urban contexts. Contradictory impacts often occur between daytime and nighttime, or different seasons, which requests trade-offs to be achieved when proposing design strategies.

Characterization of stability limits of Ledinegg instability and density wave oscillations for two-phase flow in natural circulation loops

A detailed study of excursive (or Ledinegg) instability and density wave oscillations (DWOs) is carried out for two-phase flow in a natural circulation loop. The maps in the parametric space have been obtained, which indicate excursive instability (Ledinegg instability) as well as density wave oscillations (DWOs). The dynamic (DWOs) and static (Ledinegg) stability boundary on these maps have been drawn. These diagrams dealing with the interaction of Ledinegg instability and DWOs have rarely been reported, and detailed mathematical analysis of these maps is lacking. In the present work, a detailed study of such interactions is carried out. It is also noted that the Ledinegg instability is a manifestation of saddle node bifurcation or limit point (LP) for the dynamical system of natural circulation loop. Density wave oscillations in the dynamical system of natural circulation loop can be observed with the Hopf bifurcation. The detailed bifurcation analysis of these instabilities shows that stability maps can be divided into three broad regions, the first region can only have DWOs (Hopf bifurcation), and the second region can have Ledinegg as well as DWOs (Hopf bifurcation and saddle node bifurcation co-exists), while the third region can have only Ledinegg instability (saddle node bifurcation). The first and second region are separated by a Cusp point (CP) and it is found that between CP and Bogdanov-Takens (BT) bifurcation point both Hopf and LP exist, due to presence of both DWOs and Ledinegg instability. The region beyond BT bifurcation point only has Ledinegg or excursive instability. Moreover, DWOs in the first region have two types of Hopf bifurcation depending on the nature of limit cycles. These subcritical and supercritical Hopf bifurcations, are separated by the Generalized Hopf (GH) bifurcation. Abovementioned three regions are observed only for the Type II DWOs stability boundary, whereas Type I DWOs have only subcritical and supercritical Hopf bifurcations. The impact of design parameters on the saddle-node curve along with the shifting of interaction point (Bogdanov-Takens bifurcation) have been investigated as well.

ADC-Based Backplane Receivers: Motivations, Issues and Future

The analog-to-digital-converter-based (ADCbased) backplane receivers that consist of a front-end ADC followed by a digital equalizer are gaining more popularity in recent years, as they support more sophisticated equalization required for high data rates, scale better with fabrication technology, and are more immune to PVT variations. Unfortunately, designing an ADC-based receiver that meets tight power and performance budgets of high-speed backplane link systems is non-trivial as both frontend ADC and digital equalizer can be power consuming and complex when running at high speed. This paper reviews the state of art designs for the front-end ADC and digital equalizers to suggest implementation choices that can achieve high speed while maintaining low power consumption and complexity. Design-space exploration using system-level models of the ADC-based receiver allows through analysis on the impact of design parameters, providing useful information in optimizing the power and performance of the receiver at the early stage of design. The system-level simulation results with newer device parameters reveal that, although the power consumption of the ADC-based receiver may not comparable to the receivers with analog equalizers yet, they will become more attractive as the fabrication technology continues to scale as power consumption of digital equalizer scales well with process.

Parametric analysis of glenoid implant design and fixation type.

Common post-operative problems in shoulder arthroplasty such as glenoid loosening and joint instability may be reduced by improvements in glenoid design, shape, material choice, and fixation method. A framework for parametric analysis of different implant fixation configurations was developed in order to efficiently sift through potential glenoid component designs. We investigated the influence of design factors such as fixation type, component thickness, and peg position, number, diameter, and length in a multi-factorial design investigation. The proposed method allowed for simultaneous comparison of the mechanical performance of 344 different parametric variations of 10 different reference geometries with either large central fixation features or small peripheral pegs, undergoing four different worst-case scenario loading conditions, and averaging 64.7 s per model. The impact of design parameters were assessed for different factors responsible for post-operative problems in shoulder arthroplasty, such as bone volume preservation, stresses in the implant, central displacement or fixation stability, and the worst performing geometries all relied on conventional central fixation. Of the remaining geometries, four peripheral fixation configurations produced von Mises stresses comfortably below the material's yield strength. We show that the developed method allows for simple, direct, rapid, and repeatable comparison of different design features, material choices, or fixation methods by analyzing how they influence the bone-implant mechanical environment. The proposed method can provide valuable insight in implant design optimization by screening through multiple potential design modifications at an early design evaluation stage and highlighting the best performing combinations according to the failure mechanism to mitigate. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:775-784, 2017.

Impact of design parameters on the performance of non-thermal plasma air purification system

In this study, a dielectric barrier discharge (DBD) non-thermal plasma experimental set-up is utilized to investigate the effect of design parameters including the configuration and type of electrodes as well as the size of the reactor on the energy consumption and the rate of ozone generation. Results show that increasing the residence time by applying a larger length of the inner electrode causes an earlier plasma ignition, as well as formation of larger amounts of ozone for a given specific input energy (SIE). Changing the configuration and the type of the ground electrode shows that this electrode configuration is a dominant parameter for enhancing the energy yield in the plasma reactor. Furthermore, it was noted as the size of the reactor is increased, by increasing the gap between the electrodes, higher level of SIE is needed to reach the same level of ozone concentration.

지표수 열교환기의 용량과 적용 효과에 대한 설계 인자의 영향

Abstract : Commercial buildings are generally cooling-dominated and therefore reject more heat to a vertical ground heat exchanger(GHE) than they extract over the annual cycle. Shallow ponds can provide a cost- effective means to balance the thermal loads to the ground and to reduce the length of GHE. The objective of this work has been to develop a design tool for surface water heat exchanger(SWHE) submerged in shallow pond. This paper presents the analysis results of the impact of design parameters on the length of SWHE and its application effect on geothermal heat pump(GHP) system using vertical GHE. In order to analysis, We applied  -  method on designing the length of SWHE. Analysis results show that the required pipe length of SWHE was decreased with the increase of approach temperature difference and with the decrease of pipe wall thickness. In addition, when the SWHE was applied to the GHP system, the temperature of vertical GHE was more stable than that of standalone GHE system.

Numerical simulation of the impact of design parameters on the performance of back-contact back-junction solar cell

This work presents a study based on electro-optical numerical simulations of the impact of geometrical and doping parameters on main figures of merit of crystalline silicon back-contact back-junction solar cells. State-of-the-art physical models in combination with two-dimensional simulations performed by a TCAD tool have been adopted to carry out an extensive and detailed analysis of the influence of many fabrication parameters on performance. The studied design parameters are the doping level in front surface field (FSF), back surface field (BSF) and emitter, and the main geometrical parameters. A doping level value that allows the maximization of the efficiency for the three regions can be clearly identified. In particular, for BSF and emitter, an efficiency degradation is observed for relatively lower doping values and is ascribed to the higher contact recombination while for higher doping values the Auger recombination plays a significant role in reducing the ultimate efficiency. In FSF region the recombination due to defects at the front interface is the main limiting mechanisms for efficiency. On the basis of our analysis, a marked sensitivity of the efficiency to the gap and pitch size is caused by the series resistance increase. The efficiency exhibits a maximum value for an emitter coverage fraction (R) of 85 %. However, in the case of lower emitter coverage, Auger, Shockley---Read---Hall (SRH): in bulk and at interfaces are detrimental for the cell conversion efficiency.

Experimental Study Of SBPWM For Z-Source Inverter Five Phase

On the basis of a conventional Z-source inverter, this paper presents an extension of the existing study about a driving scheme implementation of a simple boost pulse width modulation under open loop system for five phase two level system. The impact of design parameter (fixed modulation index and switching frequency) versus performance parameter (capacitor voltage, inductor current, total harmonic distortion and DC link voltage) are studied and analysed. To validate the advantages of Z-source five-phase inverter, the driving scheme are simulated using Matlab/Simulink and verified with real-time target board eZdsp<sup>TM</sup> TMS320F28335. From the study, it was found that under specified modulation index and switching frequency, the THD of an output current fulfilled the EN61000-3-2 standard.

Parametric Macromodels for Efficient Design of Carbon Nanotube Interconnects

The continuous increase of the operating frequency and density of integrated circuits leads to consider single-wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs) as the most promising candidates for future interconnect technology because of their high current-carrying capacity and conductivity in the nanoscale, and immunity to electro-migration. Several modeling methods for SWCNT and MWCNT interconnects have been based on the multiconductor transmission line (MTL) theory. These methods are limited to nanostructures with predefined values of electrical and geometrical parameters. Since process technology continues to scale downward and physical interconnect dimensions become smaller, the impact of design parameters (e.g., layout features) on the system behavior has to be carefully investigated for a successful design by performing design space exploration, optimization, and variability analysis. These design activities require multiple system simulations for different values of design parameters, and using MTL-based solvers is not an efficient choice. Parametric macromodels can be used to accurately and efficiently model these parameter effects, avoiding the brute-force use of MTL-based solvers.

Impact of design parameters on the performance of ultraviolet photocatalytic oxidation air cleaner

Ultraviolet photocatalytic oxidation (UV-PCO) is regarded as one of the promising technologies for air purification. Previous studies on UV-PCO of ethanol were performed in an ideal bench top reactors. However, this research is focused on UV-PCO of ethanol in full-scale open test rig which closely resembles the real application of this technology. Ethanol mineralization was investigated under several conditions including two types of UV-lamps (UVC and VUV) for two different photocatalysts under varied concentrations, airflow rate and relative humidity. In each case, removal efficiency and by-products yield were compared. Furthermore, possible mechanism for by-product formation is presented. Experimental results show that acetaldehyde and formaldehyde are the main by-products of ethanol. VUV lamps increase photocatalytic oxidation of ethanol compared to UVC lamps. The increase of relative humidity decreases UV-PCO of ethanol using both VUV and UVC lamps; however, the yield of by-products in the presence of VUV lamps increases while it decreases in the presence of UVC lamps. Higher flow rate results lower removal efficiency and consequently formation of less by-products. Improvement of reaction section by increasing the number of reactors leads to higher ethanol removal efficiency, less partial oxidation, lower amount of by-products and the complete mineralization of acetaldehyde.

Combined model for shielding effectiveness estimation of a metallic enclosure with apertures

This study presents an approach which combines an analytical model developed by Robinson et al. and a model which analyses the shielding effectiveness (SE) of enclosure loss with an off-centre aperture. It is based on the analytical model of transmission lines theory and aims at predicting the SE of a metallic enclosure with apertures. The combined model is more general than other analytical methods and proposes to consider the enclosure with numerous small apertures and the incident wave with varied angles of polarisation. It is therefore far quicker to calculate the SE with the combined model which on the other hand enables the impact of design parameters to be investigated. This investigation is often difficult via numerical methods because they require high computational times and memory in order to model a problem with sufficient details. This combined model is validated by comparing the SE predictions with full-field simulations using the finite-difference time-domain technique, CST Microwave Studio simulation tools and experimental investigations of the SE in a semi-anechoic chamber.

In-Situ Detection of Plasma Processing Equipment Using a V-Mask Control Chart

To improve equipment throughput and device yield, plasma processing equipment should be tightly monitored. A cumulative-sum (CUSUM) control chart is used to monitor off-line process qualities. In this study, a V-mask control chart (VCC) is presented for detecting in-situ process variability. This consisted of a modified cumulative-sum and a V-mask-parameterized belief function. The presented control chart was applied to monitor a radio frequency matching of plasma impedance. Experimental data were measured by using a real-time impedance monitoring system. Detection performance was studied either for the fixed or time-varying VCC parameters. Analysis was more detailed by defining several diagnostic parameters. The detection performance of VCC monitor system was very sensitive to the variations in the design parameters. Optimizing the impact of design parameters considerably improved the detection performance of VCC system. In particular, VCC employing time-varying parameters demonstrated improved detection accuracy. The presented technique can be utilized to monitor other in-situ equipment data.

Evaluation of Transportation and Acceptance Strategies Associated with the Potential Yucca Mountain Waste Management System

This paper describes the development and use of an integrated model to explore the impact of design parameters and operational decisions on storage and transportation aspects of the preclosure activity period for the potential repository at Yucca Mountain (YM), Nevada. The model provides an opportunity to perform analyses of various YM preclosure “scenarios.” Storage and transportation aspects of the preclosure system are evaluated with the goal of identifying important design parameters and understanding system interactions, thereby providing a tool to recognize trade-offs and dependencies between storage demands at the waste generation sites and the repository.This application of the model explores changes in assumptions regarding the following parameters: (a) year the transportation, aging, and disposal (TAD) canister becomes available; (b) year that YM opens; (c) thermal limit for emplacement; (d) thermal limit for transportation; and (e) utility strategies for selecting assemblies for dry storage loading.The response variables measured are (a) dry storage containers loaded because of lack of capacity in the spent nuclear fuel pools, (b) TAD canisters that could potentially be loaded before YM opens (assuming utilities begin using the TAD canister as soon as it is commercially available), (c) pools from which shipments to YM originate each year, (d) years aboveground aging is required at YM, and (e) containers in the aging facility at YM each year.Results indicate that allowing utilities to trade allocations, prioritizing the trading based on least remaining capacity in the spent nuclear fuel pools, could reduce dry storage demands at the utility sites, decrease the number of pools making shipments each year, and increase the efficiency of the transportation system. This type of prioritization for allocations can provide these improvements without adversely impacting the required aboveground aging at YM in the case that younger fuel is sent first. Consequently, there may be incentive for utilities to negotiate the trading of allocations if they wish to reduce their expected dry storage demands after shipments commence to YM.

Enhancement of a double-effect absorption cooling system using a vapor recompression absorber

One of the limitations of aqueous lithium bromide (LiBr/Water) single-effect absorption chillers is their inherently low COP and their inability to take advantage of the availability of high temperature heat to achieve higher COPs. Recent efforts to develop triple or even quadruple-effect absorption chillers appear unlikely to find adequate support in the current deregulated utility marketplace because of their first-cost premiums, corrosion problems associated with high temperature operation, and an oversize footprint. Double-effect cycles, on the other hand, are beginning to capture a significant portion of the heat activated cooling marketplace. This study investigates the effect of adding a Vapor Recompression Absorber (VRA) to a double-effect machine. The VRA, which can be retrofitted into an existing or constructed as part of a new double-effect absorption chiller, is an adiabatic component and uses heat released by condensation to evaporate more refrigerant. This causes an increase in the refrigerant flow rate in the refrigerant circuit, increasing the cooling capacity of the system. Hence, a system utilizing a VRA can achieve higher COPs. This paper presents methods to mathematically characterize the VRA and numerical simulations of a double-effect absorption system employing the VRA unit. The performance enhancement is investigated and the benefits in terms of improving COP and capacity are documented. Also, the impact of design parameters is documented.

Experimental and numerical evaluation of busbar trunking impedance

Abstract This paper reports on experimental and numerical evaluation of the impedance of busbar systems with ferromagnetic enclosures (trunking). A linear model is developed in which the ferromagnetic material is approximated by a ‘linear’ material with an ‘equivalent’ relative permeability. The validation of this linear model is carried out through laboratory measurements on a sample system, and a reasonable level of accuracy is demonstrated. With this model, system impedance can be computed by employing the BEM software. The impact of design parameters, such as relative permeability, separation of bars, trunking size, etc on system impedance is discussed. Finally, the impact of these parameters on magnetic shielding is presented for the comparison.

A Video Server cost/performance Estimator tool

The Video Server Estimator (VSE) is an analytical tool which allows a user to perform a cost/performance analysis of video servers with hierarchical storage. The underlying model comprises multiple systems, main memory, expanded storage, disks and a tape library. The main objective of the tool is to optimally allocate the video files to different storage media based on the system parameters and the video file request probability distribution. The cost and the size of the video server that can accommodate a customer profile are determined. Furthermore, the impact of design parameters on the cost and performance are examined through a parametric analysis.