Establishing a limit of recognition for a vapor sensor array

Organic vapor analysis with microsensor arrays relies principally on two output parameters: the response pattern, which provides qualitative information, and the response sensitivity, which determines the limit of detection (LOD). The latter is used to define the operating limit in the low-concentration range, under the implicit assumption that, if a vapor can be detected, it can be identified and differentiated from other vapors on the basis of its response pattern. In this study, the performance of an array of four polymer-coated surface acoustic wave vapor sensors was explored using calibrated response data from 16 solvent vapors in Monte Carlo simulations coupled with pattern recognition analysis. The statistical modeling revealed that the ability to recognize a vapor from its response pattern decreases with decreasing vapor concentration, as expected, but also that the concentration at which errors in vapor recognition become excessive is well above the calculated LOD in most cases, despite the LOD being based on the least sensitive sensor in the array. These results suggest the adoption of a limit of recognition (LOR), defined as the concentration below which a vapor can no longer be reliably recognized from its response pattern, as an additional criterion for evaluating the performance of multisensor arrays. A generalized method for estimating the LOR is presented, as well as a means for improving the LOR via residual error analysis.     

Surface Current Determination from Electric-Fields Distribution Measurement

Determination of induced surface current on cylindrical reflectors in a parallel-plate region from measurements of electricfields distribution is described. The probe-reflector interaction in the measurement of electric-fields distribution is examined and the requirement of probe reflector spacing which ensure the small interaction is also investigated.     

Adaptable Scheduling Algorithm for Grids with Resource Redeployment Capability

Two distinct characteristics of grid computing systems are resource heterogeneity and availability variation. There are many well-designed scheduling algorithms proposed for heterogeneous computing systems. However, the availability variation is seldom considered in developing scheduling ongoing applications on a grid. In this paper, two scheduling algorithms called AMOF and AMOSF are proposed. Both of them consider availability variation as well as resource heterogeneity while scheduling an ongoing workflow application on the grid. An experiment has been conducted to demonstrate that AMOF and AMOSF algorithms outperform the well-known scheduling algorithms: GS and HEFT in most of the cases.     

A novel approach for optimizing the optical performance of the broadband tap coupler

An integrated approach using neural networks, exponential desirability functions and genetic algorithms to optimize parameter design problems with multiple responses is presented. The proposed approach aims to identify the input parameter settings to maximize the overall minimal satisfaction level with respect to all the responses. The proposed approach is illustrated by optimizing the fused process parameters created during fused biconic taper coupler development to improve the performance and reliability of a 1% (1199) single-window broadband tap coupler. The proposed solution procedure was implemented on a Taiwanese manufacturer of fibreoptic passive components. The implementation results demonstrate the practicability of the method. Comparison analysis revealed that the proposed procedure outperformed the traditional Taguchi method in resolving multi-response parameter design problems.     

Composite hydrogeological investigation and characterisation methods applied at a nuclear power plant site in Taiwan

Drawing from the lessons learnt from the Fukushima nuclear disaster in Japan, the assessment of subsurface environmental hazard around nuclear power plants has emerged as a critical task. Consequently, aiming to better understand the possible environmental impact of radiation leaks into the groundwater, a prescreening programme was initiated in 2011 by the Taiwanese government. As part of this programme, this study conducted various borehole prospecting techniques to identify in situ hydrogeological characteristics at Chin‐Shan Nuclear Power Plant. Borehole electrical log, sonic log and temperature/conductivity log were conducted to explain the regional lithologic conditions and permeability of the formation. In conjunction with this, the interwell tracer and pumping test was carried out to simultaneously determine the hydraulic parameters. In our opinion, the implementation of such in situ end‐to‐end investigations is essential in interpreting in situ fluid and solute transport dynamics prior to programming any numerical scheme for early warning, vulnerability assessment and regular monitoring of a nuclear power plant site.     

Characteristics of flow field near sea bottom in a combined wave and current motion

Abstract

A reasonable time‐invariant eddy viscosity model is proposed to describe turbulent flow over a rough sea bottom in a combined wave‐current system. The linearized governing equations are solved for the wave and current kinematics both inside and outside the wave boundary layer. The results of velocity profile, friction factor and apparent roughness in a wave‐current motion are presented. The friction factors are shown to be consistent with previous theoretical results for the limiting cases of pure wave and pure current motions. Present results are compared favorably with the available data.     

Coping knowledge boundaries between information system and business disciplines: An intellectual capital perspective

Information system development can be considered a collaboration between users and developers. The inability to leverage the localized knowledge embedded in these two stakeholders hinders software development work to achieve high performance. Exploring the ways to counter this difficulty is then critical. This study applies an intellectual capital perspective to address the issues around spanning the knowledge boundary between developers and users. Our findings highlighted how important effective knowledge boundary spanning is to both product and project quality. Furthermore, three dimensions of intellectual capital increased the degree to which knowledge boundary spanning was effective.     

Feasibility evaluation of fermentative biomass-derived gas production from condensed molasses in a continuous two-stage system for commercialization

The excessive burning of fossil fuels is one of the main sources of emissions of carbon dioxide (CO₂) which causes the greenhouse effect. The effect could be resulted in climate changes and disorder of our ecosystem. Thus, bioenergy developments will play important roles to help decreasing CO₂ emission for better global environment in the future. In the domain of biohydrogen production, biomass including: cellulose, wastewater and agricultural waste are the main resources to maintain feedstock demand. Developing sustainable energy with sustainable feedstock sources like sugary wastewater by using two-stage biomass-derived gas production system might bring great economic profits to business. In this study, the system will be chosen to testify its sustainability when producing the sugary wastewater to renewable source energy. The commercial potential analysis is derived from the internal rate of return (IRR). The novelty finding of this study, as the result showed, found out that the energy recovery is 1.12 times higher than single stage. According to the IRR analysis with the calculated years of 15 years, the IRR is 32.47% that means the system can payback within 3.19 years. Therefore, the feasibility of commercialization potential of biomass-derived gas production system can be verified.     

Effect of midblock on the morphology and properties of blends of ABA triblock copolymers of PDLA-mid-block-PDLA with PLLA

A method to overcome the brittleness of poly (l-lactic acid) (PLLA) by kinetically trapping a continuous low T_g amorphous phase is presented. This morphology is accomplished by exploiting the significant difference in the crystallization temperatures of PLLA vs its stereocomplex with the poly (d-lactic acid) (PDLA) isomer. In our studies, the D isomer is the end block of a triblock copolymer with a configuration of the form PDLAn–Soft Blockm–PDLAn. As demonstrated in this study, when blended with PLLA, the obtained morphology, and improvement in the sample toughness and flexibility, strongly depend on the miscibility of the midblock in the triblock copolymer with the matrix PLLA. The difference in the chemical nature of the midblock clearly affected the stereocomplex crystallization between the PDLA end blocks, the PLLA matrix polymer, and the morphology formed. It is found that the miscible midblock gives rise to a soft continuous amorphous phase while in the case of an immiscible midblock, a glassy phase separated amorphous phase is formed. Dramatically different physical properties can be obtained for various PLLA/triblock copolymer blends giving access to tough, yet flexible, semicrystalline PLLA blends.