Remote database access in the distributed computing environment

This paper describes the design, implementation and testing of a set of software modules that are used for remote database access in a distributed computing environment. The goal of our research and development is to implement a client server model using Structured Query Language (SQL) functions in the Open Software Foundation's (OSF) distributed computing environment (DCE). This design is compared with another which simply uses the sockets application programming interface (API), running over the transmission control protocol/internet protocol (TCP/IP), and is implemented in subroutines that act similar to the remote procedure call (RPC) generated stub code. The prototypes for the remote SQL access project are implemented using an IBM RISC System/6000 (the client) running the AIX operating system and an IBM AS/400 (the server) running the OS/400 operating system. We selected the AS/400 for its database abilities, and the RISC System/6000 since the DCE software is available for it.     

Experimental and calculated effectiveness of a radiochromic dye film to stopping 21 MeV 7Li and 64 MeV 16O ions

Relative radiation effectiveness, RE, of 21 MeV ⁷Li and 64 MeV ¹⁶O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a δ-ray theory for heavy charged particles developed by Katz et al. The experiment was designed to test calculations particularly in the Bragg-peak region of the slowing down particles where significant deviation between theory and experiment was found. Fitting of the characteristic D₃₇ dose and the size of the radiation sensitive element in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the δ-ray spectrum and the slowing down spectrum of electrons from low-LET radiation, and partly from approximations in the calculated distribution of energy deposition of the δ-rays.     

LOCST: A Built-In Self-Test Technique

A built-in self-test technique utilizing on-chip pseudorandom-pattern generation, on-chip signature analysis, a ``boundary scan' feature, and an on-chip monitor test controller has been implemented on three VLSI chips by the IBM Federal Systems Division. This method (designated LSSD on-chip self-test, or LOCST) uses existing level-sensitive scan design strings to serially scan random test patterns to the chip's combinational logic and to collect test results. On-chip pseudorandom-pattern generation and signature analysis compression are provided via existing latches, which are configured into linear-feedback shift registers during the self-test operation. The LOCST technique is controlled through the on-chip monitor, IBM FSD's standard VLSI test interface/controller. Boundary scan latches are provided on all primary inputs and primary outputs to maximize self-test effectiveness and to facilitate chip I/O testing. Stuck-fault simulation using statistical fault analysis was used to evaluate test coverage effectiveness. Total test coverage values of 81.5, 85.3, and 88.6 percent were achieved for the three chips with less than 5000 random-pattern sequences. Outstanding test coverage (≫97%) was achieved for the interior logic of the chips. The advantages of this technique, namely very low hardware overhead cost (≪2%), design-independent implementation, and effective static testing, make LOCST an attractive and powerful technique.     

Occurrence and removal of priority pollutants by lamella clarification and biofiltration

This study investigates the occurrence of all priority substances (n = 41) listed in the Water Framework Directive and additional substances (n = 47) in raw sewage, as well as the removal performance of lamella clarification and biofiltration techniques. Once the efficiency of both types of techniques has been assessed for typical wastewater parameters, the differences in each technique's ability to remove pollutants becomes obvious; nevertheless, pollutant removal in quantitative terms still depends on the physico-chemical properties of the compounds used and operating conditions within the selected facility. For lamella clarification, the removal of organic chemicals was found to be primarily correlated with their sorption potential and, hence, strongly dependent upon log K_ow of the compound under study. Compounds with a strong hydrophobic character (log K_ow > 4.5) are removed to a significant extent (approx. 85%), while hydrophilic compounds (log K_ow < 3.5) are poorly removed (<20%). For biofiltration, the removal of chemicals appears to be compound-dependent, although this outcome involves several mechanisms, namely: i) physical filtration of total suspended solids, ii) volatilisation, iii) sorption, and iv) biotransformation of substances. Even if the complex processes within a biofilter system do not yield an accurate prediction of pollutant removal, two groups of chemicals can still be clearly identified: i) hydrophobic or volatile compounds, for which moderate to high removal rates are observed (from 50% to over 80%); and ii) hydrophilic, non-volatile and refractory compounds for which a low removal rate would be expected (<20%).     

Multi-scale Discontinuous Galerkin Method for Solving Elliptic Problems with Curvilinear Unidirectional Rough Coefficients

In this paper, we propose a multi-scale discontinuous Galerkin (DG) method for second-order elliptic problems with curvilinear unidirectional rough coefficients by choosing a special non-polynomial approximation space. The key ingredient of the method lies in the incorporation of the local oscillatory features of the differential operators into the approximation space so as to capture the multi-scale solutions without having to resolve the finest scales. The unidirectional feature of the rough coefficients allows us to construct the basis functions of the DG non-polynomial approximation space explicitly, thereby greatly increasing the algorithm efficiency. Detailed error estimates for two-dimensional second-order DG methods are derived, and a general guidance on how to construct such non-polynomial basis is discussed. Numerical examples are also presented to validate and demonstrate the effectiveness of the algorithm.     

Characterization of an Ecuadorian crude using a vibrating-tube densimeter and a vibrating-wire viscometer

Abstract

Two accurate experimental techniques have been used to characterize a sample of crude from an oil field of the Ecuadorian Amazon Region. An automated Anton Paar DMA HPM vibrating-tube densimeter was used to measure densities. A vibrating-wire viscometer was developed to accurately measure viscosities for pure compounds and mixtures. The experimental data on density were correlated with the Tait equation. The experimental data on viscosity were fitted using an empirical representation of Vogel-Fulcher-Tamman (VFT) combined with the Tait equation, as well as the Mehrotra equation.     

Construction,application and validation of selection evaluation model (SEM) for intelligent HVAC control system

Design teams are confronted with the quandary of choosing apposite building control systems to suit the needs of particular intelligent building projects, due to the availability of innumerable ‘intelligent’ building products and a dearth of inclusive evaluation tools. This paper is organised to develop a model for facilitating the selection evaluation for intelligent HVAC control systems for commercial intelligent buildings. To achieve these objectives, systematic research activities have been conducted to first develop, test and refine the general conceptual model using consecutive surveys; then, to convert the developed conceptual framework into a practical model; and, finally, to evaluate the effectiveness of the model by means of expert validation. The results of the surveys are that ‘total energy use’ is perceived as the top selection criterion, followed by the ‘system reliability and stability’, ‘operating and maintenance costs’, and ‘control of indoor humidity and temperature’. This research not only presents a systematic and structured approach to evaluate candidate intelligent HVAC control system against the critical selection criteria (CSC), but it also suggests a benchmark for the selection of one control system candidate against another.     

Morphological, viscoelastic and thermal properties of poly(vinylidene Fluoride)/POSS nanocomposites

Nanocomposites of poly(vinylidene fluoride) and polyhedral oligomeric silsesquioxane were prepared through melt blending. Morphology, viscoelastic and thermal properties were investigated. Up to 1 wt.% the processing conditions were efficient to prevent formation of large POSS agglomerates. In the nanocomposites with higher POSS contents these conditions could not avoid it, because of the strong interaction among POSS molecules. The presence of two different crystalline phases in nanocomposite was evidenced by X-ray diffraction and Fourier Transformed Infra-Red Spectroscopy. The nanocomposite with 5 wt.% content had the highest values for degree of cristallinity. The polyhedral oligomeric silsesquioxane molecules are acting as lubricant in the system, once lower values for storage modulus as well as for viscosity were observed.     

A liquid chromatography--tandem mass spectrometry multiresidue method for quantification of specific metabolites of organophosphorus pesticides, synthetic pyrethroids, selected herbicides, and deet in human urine

The ability to estimate low-dose human exposure to commonly used pesticides often is requested in epidemiologic studies. Therefore, fast and robust methods are necessary that can measure many analytes in the same sample. We have developed a method for high-throughput analysis of 19 markers of commonly used pesticides in human urine. The analytes were seven specific metabolites of organophosphorus pesticides, five metabolites of synthetic pyrethroids, six herbicides or their metabolites, and one insect repellant. Human urine (2 mL) was spiked with stable isotopically labeled analogues of the analytes, enzymatically hydrolyzed, extracted using solid-phase extraction, concentrated, and analyzed using high-performance liquid chromatography-tandem mass spectrometry. The sample was divided into two portions and analyzed on two different mass spectrometers, one using atmospheric pressure chemical ionization (APCI) and the other using turbo ion spray atmospheric pressure ionization (TIS). All analytes except the pyrethroid metabolites were analyzed using APCI. The detection limits for all analytes ranged from 0.1 to 1.5 ng/mL of urine, with the majority (17) below 0.5 ng/mL. The analytical precision for the different analytes, estimated as both the within-day and between-day variation, was 3-14 and 4-19%, respectively. The extraction recoveries of the analytes ranged from 68 to 114%. The throughput, including calibration standards and quality control samples, is approximately 50 samples a day. However, the analysis time with the TIS application is much shorter, and if only pyrethroid metabolite data are of interest, the throughput can be increased to 100-150 samples/day.     

Single-walled carbon nanotube induces oxidative stress and activates nuclear transcription factor-kappaB in human keratinocytes

Carbon nanotubes are now becoming an important material for use in day to day life because of their unique physical properties. The toxicological impact of these materials has not yet been studied in detail, thereby limiting their use. In the present study, the toxicity of single-walled carbon nanotubes (SWCNT) was assessed in human keratinocyte cells. The results show increased oxidative stress and inhibition of cell proliferation in response to treatment of keratinocytes with SWCNT particles. In addition, the signaling mechanism in keratinocytes upon exposure to SWCNT particles was investigated. Results from the study suggest that SWCNT particles activate NF-kappaB in a dose-dependent manner in human keratinocytes. Further, the mechanism of activation of NF-kappaB was due to the activation of stress-related kinases by SWCNT particles in keratinocytes. In conclusion, these studies show the mechanism of toxicity induced by SWCNT particles.