Experience with model-based performance, reliability, and adaptability assessment of a complex industrial architecture

In this paper, we report on our experience with the application of validated models to assess performance, reliability, and adaptability of a complex mission critical system that is being developed to dynamically monitor and control the position of an oil-drilling platform. We present real-time modeling results that show that all tasks are schedulable. We performed stochastic analysis of the distribution of task execution time as a function of the number of system interfaces. We report on the variability of task execution times for the expected system configurations. In addition, we have executed a system library for an important task inside the performance model simulator. We report on the measured algorithm convergence as a function of the number of vessel thrusters. We have also studied the system architecture adaptability by comparing the documented system architecture and the implemented source code. We report on the adaptability findings and the recommendations we were able to provide to the system’s architect. Finally, we have developed models of hardware and software reliability. We report on hardware and software reliability results based on the evaluation of the system architecture.     

Comparing awareness and use of content-free software in comprehensive schools

The study reports on a survey into the use of content-free computer software by comprehensive school teachers in South Wales. The survey includes questions on computer resources, staff training, level of awareness and utilization by year group and by subject taught. The findings suggest that many more teachers are aware of the potential of content-free software than are actually using them in their lessons. A shortfall in training provision together with the inequitable distribution of computers between subjects are major factors limiting the use of such software. Modern Languages and Humanities are generally poorly provided for in terms of hardware resources. However, Science (which has ample hardware) seems to make relatively little use of content-free software while Business Studies and Design Technology use it extensively. Sixth form teaching seems generally to ignore the potentials of computer-aided learning by means of content-free software.     

Flow cytometric analysis of microsporidia belonging to the genus Encephalitozoon

Flow cytometry was used in the identification of human microsporidia belonging to the genus Encephalitozoon. Microsporidian spores of Encephalitozoon hellem, E. cuniculi, and E. intestinalis were propagated in axenic cultures of monkey kidney E6 cells, purified with Percoll, and exposed to homologous and heterologous rabbit antiserum and monoclonal antibody prepared against E. hellem spores. After reaction to goat anti-rabbit immunoglobulin G (IgG) or goat anti-mouse IgG conjugated to fluorescein isothiocyanate, fluorescence histograms from gated data on light-scatter profiles showed that rabbit anti-E. hellem serum was reactive to E. hellem spores but also had cross-reactivity to spores of E. cuniculi and E. intestinalis. On the other hand, fluorescence histograms showed that rabbit anti-E. cuniculi and rabbit anti-E. intestinalis sera were reactive with homologous spores only. Monoclonal antibody prepared against E. hellem reacted only with spores of E. hellem. Neither the polyclonal antibodies nor the monoclonal antibodies reacted with Cryptosporidium parvum oocysts. Fluorescence histograms of spores treated with 10% formalin also showed reactivity, but the number of events in the most intense peaks of fluorescence was fewer (7 to 42%, depending on species) than the number of events in the most intense peaks of fluorescence for nontreated spores. By flow cytometry, formalin-treated and nontreated spores of Encephalitozoon were identified to the species level by using gated data on light-scatter profiles and analyzing the fluorescence histograms from the indirect immunofluorescence of the spores. Once a procedure is established for the isolation of Encephalitozoon spores from clinical specimens, identification of spores by flow cytometry may be useful not only for diagnosis but also for epidemiologic studies.     

Studies on a toxic metabolite from the mould Wallemia

While monitoring the occurrence of toxigenic moulds in foods, using a bioassay screen, it was shown that an isolate of Wallemia sebi produced toxic effects in several of the bioassays. The toxic metabolite was isolated and purified using solvent extraction, TLC and HPLC coupled with the brine shrimp assay to monitor the toxic fractions. The purified toxin, which we propose to call walleminol A, has been partially characterized by mass spectroscopy, nuclear magnetic resonance, ultraviolet and infrared spectroscopy. It can be provisionally interpreted as a tricyclic dihydroxy compound, C15H24O2, with structural features characteristic of a sesquiterpene with an isolated double bond, but further work is required to characterize this compound unequivocally. The minimum inhibitory dose of walleminol A in the bioassays is approximately 50 micrograms/ml, which is comparable with a number of mycotoxins such as citrinin and penicillic acid.     

3G Trials and Developments

This paper summarises the many activities that formed a vigorous and innovative phase of understanding 3rd generation systems and their potential service/product offering.Experience from the introduction of 2nd generation GSM systems showed that, even though based upon strong standards, real hands-on development to validate the design activities was essential for both a workable standard and a smooth and successful service deployment. Trials activities are used to overcome the lack of validation and to bring innovation through integration of capabilities and devices — they consist of two areas. Firstly, a number of test radio systems were examined and used in the validation of network planning tools plus measurement or real throughput figures, and, secondly, some service scenarios were developed and implemented on an all-IP network to demonstrate that IP can deliver a marketable services level. The interaction with wireless systems and the impact of that on the application were also examined.     

Investigation of solid electrolyte interfacial layer development during continuous cycling using ac impedance spectra and micro-structural analysis

The formation of passivating surface films on the electrodes of a lithium-ion polymer battery was investigated at various cycling state using ac impedance spectroscopy and scanning electron microscopy (SEM). A sealed commercial cell (Sony Co.) with a nominal capacity of 840 mAh was used for the experiment. An equivalent circuit used to model the impedance spectra show that, with continuous cycling there is a relatively large increase in the interfacial impedance and charge transfer resistances after a few hundred charge–discharge cycles. It was observed that the cell capacity decrease with increase cell impedance. SEM analysis on the electrodes shows that during continuous charge–discharge cycling, the deposition of sub-micro-size particles and dissolution of surface films on the graphite surface. This observation is consistent with increase in cell impedance as a function of charge/discharge cycling.     

Assessing disharmony and disaffection in intimate relationships: Revision of the Marital Satisfaction Inventory factor scales.

Previous research has identified 2 broad components of distress in intimate relationships: overt conflict, or disharmony, and emotional distance, or disaffection. Using confirmatory factor analysis, the authors derived 2 broadband scales of disharmony and disaffection from the Marital Satisfaction Inventory-Revised (D. K. Snyder, 1997), building upon previous measures of these constructs (D. K. Snyder & Regts, 1982) derived from the original instrument. The new scales demonstrated high internal consistency and test-retest reliability, as well as discriminative validity and convergent validity with independent criteria of relationship functioning. Distinct distributions of these scales in community and clinical samples suggested their complementary role in research on intimate relationships and assessment of couples in treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions of refractory materials with molten gasifier slags

The current study focuses on the analysis of sessile-drop interfacial reactions between two synthetic slags (based on average ash chemistries of coal and petcoke feedstock) and two refractory materials (90 wt% Cr₂O₃-10 wt% Al₂O₃ and 100 wt% Al₂O₃), using a Confocal Scanning Laser Microscope (CSLM). Ground slag samples (less than 325 mesh) were placed at specific microstructure locations on refractory substrates and heated to 1500 °C in an atmosphere of CO/CO₂ gas mixture (volume ratio = 1.8), using a gold-image heating chamber. Cross-sections of the slag/refractory interface indicated unique slag penetration into preferred areas of the refractory and grain dissolution into the slag which promoted spalling of the refractory. Initially, the slag attacked both grain boundaries and fine microstructure areas, freeing alumina grains into the slag. The formation of VO_x-based crystalline material in the petcoke slag was found to alter the liquid composition. Chemical spalling of Cr-containing crystal layer also facilitated degradation of the refractory.     

Heat‐Transfer Processes in a Plasma Reactor in Destruction of Pesticides

The possibility of using a multijet electric arc plasmachemical reactor for decontamination and destruction of different powder pesticides with an expired effective date and storage life which have not been used in agriculture is studied. Studies of heat transfer are conducted on a setup operating without processing of raw material and with supply of pesticides (isophen and butyl ester of 2,4dichlorophenoxyacetic acid) to the reactor. The composition of waste gases at the reactor outlet is studied.     

The performance of a new biological water quality score system based on macroinvertebrates over a wide range of unpolluted running-water sites

The occurrence of families of macroinvertebrates has recently been used as the basis for the BMWP (Biological Monitoring Working Party) system of assigning scores to lotic sites. In this study the performance of the system across 268 sites on 41 rivers providing a wide range of physical and chemical features has been appraised. Changes in score and ASPT (average score per taxon) with respect to season and sampling effort have been examined. Seasonal variations were relatively slight and it is concluded that samples taken in any of the three seasons, spring, summer or autumn, were likely to provide consistent estimates of score and particularly ASPT. Sample replication led to substantial accretion of scores but had little effect on ASPT and therefore more information was obtained for less effort when ASPT was used. Data are presented on score and ASPT values for 8 groups of sites derived by multivariate classificatory techniques. Considerable variability in achievable score and ASPT was observed in the different groups of unpolluted sites. In general, scores were highest in the group at the middle of the range of environmental features and lowest in groups at the bottom of the range (lowland areas). ASPT in contrast showed a relatively steady decline in values between groups at the top (mainly upland rivers) and bottom of the range of environmental features. Attempts were made to predict score and ASPT from physical and chemical data, or physical data alone using multiple regression. Equations used to predict ASPT explained on average a higher proportion of the variance (65%) than those predicting scores (22%). It is suggested that predictive equations for ASPT will enable theoretical ASPT to be calculated, thus providing target values against which observed values can be compared. Recommendations to facilitate use and interpretation of the BMWP score system are presented.