Evaluating the damage associated with intentional network disintegration

This paper presents a method for evaluating an expected damage associated with disintegrating complex networks with a given topology into isolated sub-networks (clusters) as a result of intentional attack on randomly chosen network links. The method is based on a multi-dimensional spectra approach for evaluating the probability of network disintegration into a given number of sub-networks when a fixed number of randomly chosen links is eliminated. It also uses the contest success function that evaluates destruction probability of individual links as a function of per-link attack and defense efforts. It is assumed that the defender has no information about the attacker's actions and the attacker has no information about the network structure. The method allows the analysts to compare different network topologies and to choose one with the minimal expected damage under conditions of uncertainty. Illustrative examples are presented.     

Efficient degradation of environmental contaminants using Pd-RGO nanocomposite as a retrievable catalyst

Clean Technologies and Environmental Policy - Pd nanoparticles (NPs)/reduced graphene oxide (RGO) nanocomposite was prepared in a one-pot process by using Euphorbia stenoclada extract as...     

Evaluating the soundness of bonding using shearography

Shearography is an optical measurement technique invented to overcome several limitations of holography. One distinct advantage is that it alleviates the stringent environmental stability demanded by holography, rendering the technique practical for industrial applications. There are two modes of shearography, one for measuring surface displacement and the other for measuring surface displacement derivatives. This paper discusses the underlying principle of shearography and its application in nondestructive testing, in particular, of laminated composite structures. In flaw characterization, a thin-plate model is used for back-calculating the shape, size and location of debonds. Shearographic nondestructive testing relies on measuring the response of a defect to stresses. Two practical types of stressing for revelation of debonds are described – static loading using vacuum stressing, and dynamic stressing by means of vibrational excitation. In vibrational stressing, both single frequency excitation and broadband excitation can be used. While vacuum stressing is limited to detecting debonds with closed boundaries, the vibrational excitation can be used for detecting debonds with closed as well as opened boundaries. A major drawback associated with the use of single excitation frequency is the need for vibrating the test object within an appropriate frequency range, as otherwise the test data obtained will not readily reveal the debonds. This paper also describes a new method that uses multiple frequency sweep (equivalent to broadband excitation) which fosters rapid detection and unambiguous assessment of the soundness of adhesive bonding.     

Identification of oil contaminants on polymer coated beverage cans using fluorescence spectroscopy

In a recent publication we introduced a novel method for detection of impurities on beverage can surfaces using Raman spectroscopy. While investigating the technique, limitations emerged due to the low sensitivity of Raman scatter. This is a particular problem with the largest contributor of impurities in beverage cans: lubricants employed in the manufacturing process. This paper presents an alternative approach, using the more sensitive technique of fluorescence spectroscopy to tackle the same problem. Measurements using fluorescence spectroscopy were conducted indirectly in a cuvette as well as directly on a can surface with the aid of fiber optics. The chemometrics methods of linear discriminant analysis (LDA) and principal components analysis (PCA) were used to classify acquired spectra as belonging to one of the 16 investigated lubricants. Fiberoptic scans revealed that a successful detection and recognition of lubricant is possible down to a volume of 0.5 microL deposited on the can surface. Contaminant detection was possible at even lower levels down to 0.01 microL, but reliable identification proved difficult at such low volumes. Indirect measurements of lubricants dissolved in cyclohexane yielded the lowest detection limits between 1-0.1 ppb.     

Evaluating treatment of osteoporosis using particle swarm on a bone remodelling mathematical model

Bone loss in osteoporosis, commonly observed in postmenopausal women and the elderly, is caused by an imbalance in activities of bone‐forming osteoblasts and bone‐resorbing osteoclasts. To treat osteoporosis and increase bone mineral density (BMD), physical activities and drugs are often recommended. Complex systems dynamics prevent an intuitive prediction of treatment strategies, and little is known about an optimal sequence for the combinatorial use of available treatments. In this study, the authors built a mathematical model of bone remodelling and developed a treatment strategy for mechanical loading and salubrinal, a synthetic chemical agent that enhances bone formation and prevents bone resorption. The model formulated a temporal BMD change of a mouse''s whole skeleton in response to ovariectomy, mechanical loading and administration of salubrinal. Particle swarm optimisation was employed to maximise a performance index (a function of BMD and treatment cost) to find an ideal sequence of treatment. The best treatment was found to start with mechanical loading followed by salubrinal. As treatment costs increased, the sequence started with no treatment and usage of salubrinal became scarce. The treatment strategy will depend on individual needs and costs, and the proposed model is expected to contribute to the development of personalised treatment strategies.Inspec keywords: bone, diseases, minerals, particle swarm optimisation, patient treatment, physiological modelsOther keywords: ovariectomy, mouse whole skeleton, bone mineral density, bone resorption, bone formation, synthetic chemical agent, salubrinal, mechanical loading, bone remodelling mathematical model, particle swarm optimisation, osteoporosis treatment     

Selectivity sequences and sorption capacities of phosphatic clay and humus rich soil towards the heavy metals present in zinc mine tailing

Sorption efficacy of phosphatic clay and humus rich soil alone and on combination were tested towards heavy metals present in zinc mine tailing (Zawar Zinc Mine), Udaipur (India). Characterization of the zinc mine tailing sample indicated the presence of Pb, Cu, Zn and Mn in the concentration of 637, 186, 720 and 577microg(-1), respectively. For sorption efficacy, the zinc mine tailing soil were properly amended with phosphatic clay and humus rich soil separately and in combination and leachability study was performed by batch experiment at different pH range from 3 to 9. The data showed that the percent leachability of heavy metal in non-amended soil was 75-90%. After amendment with phosphatic clay percent leachability of heavy metals became 35-45%. Further, the addition of humus soil to phosphatic clay decreased the percent leachability up to 5-15% at all tested pH. Column leachability experiment was performed to evaluate the rate of leachability. The shape of cumulative curves of Pb, Cu, Zn and Mn showed an increase in its concavity in following order: PbCu>Zn>Mn. Further, Langmuir isotherms applied for the sorption studies indicated that phosphatic clay in the presence of humus soil had high affinity for Pb followed by Cu, Zn and Mn, with sorption capacities (b) 139.94, 97.02, 83.32 and 67.58microgg(-1), respectively.     

Evaluating ERP implementation choices on the basis of customisation using fuzzy AHP

An enterprise resource planning (ERP) system is a software solution that puts together a package that allows information flow through various levels and departments of an organisation. Manufacturing enterprises have understood the importance of information systems within their organisations and have begun using them extensively. To achieve the right fit of the ERP system to the business organisation, customisation may be needed. However, customisation is seen as an issue in the application of an ERP. There are many attributes that can be considered for the selection of an ERP system. In this paper, we have applied fuzzy analytical hierarchy process (FAHP) to a framework to evaluate an ERP for implementation purposes. The framework provides different methods for customisation of ERP. With the use of FAHP, obtained results provide a better match in terms of understanding the problem and giving options that are a closer fit to the requirements rather than providing the ‘correct’ decision to be taken. This paper is aimed at helping managers to understand and select among the various customisation options available. The application of FAHP to the framework is demonstrated with opinions gathered from managers in various companies. These opinions are translated into numerical values and are compared to the problem as a whole.     

Factors affecting the transformation of a pyritic tailing: scaled-up column tests

Two different methods for predicting the quality of the water draining from a pyritic tailing are compared; for this, a static test (ABA test) and a kinetic test in large columns were chosen. The different results obtained in the two experimental set-ups show the necessity of being careful in selecting both the adequate predictive method and the conclusions and extrapolations derived from them. The tailing chosen for the weathering tests (previously tested in shake flasks and in small weathering columns) was a pyritic residue produced in a flotation plant of complex polymetallic sulphides (Huelva, Spain). The ABA test was a modification of the conventional ABA test reported in bibliography. The modification consisted in the soft conditions employed in the digestion phase. For column tests, two identical methacrylate columns (150 cm high and 15 cm diameter) were used to study the chemical and microbiological processes controlling the leaching of pyrite. The results obtained in the two tests were very different. The static test predicted a strong potential acidity for the tailing. On the contrary, pH value in the effluents draining from the columns reached values of only 5 units, being the concentration of metals (<600 mg/L) and sulphate ions (<17,000 mg/L) very small and far from the values of a typical acid mine drainage. In consequence, the static test may oversize the potential acidity of the tailing; whereas large columns may be saturated in water, displacing the oxygen and inhibiting the microbial activity necessary to catalyse mineral oxidation.     

反渗透处理金铜矿山酸性废水

用反渗透工艺处理某金铜矿山酸性废水,试验研究了工艺条件,结果表明,通过两段反渗透处理,水回收率可达36.79%,透过液可达标排放标准;浓缩液用硫化沉淀浮选法处理,得到含铜质量分数26.3%的铜渣,铜回收率可达74%,研究结果为矿山酸性废水治理提供了一种新思路.     

Evaluating the research performance of the Greek medical schools using bibliometrics

Quality in Higher Education Institutions is the subject of several debates in the academic community in a worldwide basis and various efforts are made towards identifying ways to quantify it. In this respect, the use of bibliometrics gains significant ground as an effective tool for the evaluation of universities’ research output. In the present study, the research performance of the seven Greek medical schools is assessed by means of widely accepted and advanced bibliometric indices, such as total and average publications and citations, average and median h- and g-index with and without self-citations for all the 1,803 academics, while statistical analysis of the data was also performed in order to compare the observed differences in the mean values of the calculated indices. Considerable effort was exerted to overcome all inherent limitations of a bibliometric analysis through a meticulous data collection. This large-scale work was conducted both in school and academic rank level leading to interesting results concerning the scientific activity of the medical schools studied as units and of the various academic ranks separately, which can be partially justified with geographic and socioeconomic criteria. In general, bibliometrics demonstrate statistically significant difference in favour of Crete University medical school, while it was also found that self-citations have only marginal effect on the individual’s research profile and the average indices. Finally, the useful findings of the present study render the methodology adopted of high viability for assessing the research performance of Higher Education Institutions even in a broader context.     

Evaluating the repair of system-on-chip (SoC) using connectivity

This paper presents a new model for analyzing the repairability of reconfigurable system-on-chip (RSoC) instrumentation with the repair process. It exploits the connectivity of the interconnected cores in which unreliability factors due to both neighboring cores and the interconnect structure are taken into account. Based on the connectivity, two RSoC repair scheduling strategies, Minimum Number of Interconnections First (I-MIN) and Minimum Number of Neighboring Cores First (C-MIN), are proposed. Two other scheduling strategies, Maximum Number of Interconnections First (I-MAX) and Maximum Number of Neighboring cores First (C-MAX), are also introduced and analyzed to further explore the impact of connectivity-based repair scheduling on the overall repairability of RSoCs. Extensive parametric simulations demonstrate the efficiency of the proposed RSoC repair scheduling strategies; thereby manufacturing ultimately reliable RSoC instrumentation can be achieved.     

Eliminating contaminants with a piezoelectric transducer in the design of low-cost smart kitchen range hoods

The exhaust fan in a kitchen range hood is required to generate an adequate suction flow to eliminate the especially high levels of cooking contaminants in Chinese kitchens. Reducing the range hood noise and its power consumption down to an acceptable level is an important issue. In this paper, a low-cost smart range hood system is proposed. A sensitive piezoelectric transducer senses the level of the cooking contaminants and the output regulates the speed of the exhaust fan. Under several cooking conditions, the speed of the exhaust fan, its noise level, and the power consumption were examined. Results showed that the noise level and power consumption can be markedly reduced with the transducer and the control circuit. The average noise level is 65.66 dB and the power consumption 123.97 W, both lower than those of the conventional range hood system, which are 72 dB and 216 W, respectively.     

Removal of dust produced in the roadway of coal mine using a mining dust filtration system

Dust particles, which are produced both on the ground and in underground workspaces, significantly affect the human body and the atmosphere. In fact, underground dust hazards are more serious, especially in the heading face of coal mines. People who work in the heading face are exposed to a high concentration of fine particulate matter. Traditional methods such as water sprays, dust removal by ventilation and foam technology, cannot completely solve the problem of dust pollution. Therefore, a mining dust filtration system was designed for removing dust produced in the roadway of coal mines. The study on eight frequently used air duct arrangements indicates that the mining dust filter achieved the best dust collection efficiency when the inlet of the extraction air duct and the outlet of the forced air duct were 3?m and 13?m away from the heading face, respectively. Under the optimum condition, the dust concentration can be significantly reduced in the rear of the dust exhaust hood and gradually decreased along the direction of the roadway. The system proposed in the study reduced the dust concentration to below 3?mg/m³ in the rear of the extraction fan and greatly improved the environment in the roadway of coal mines.     

Challenges associated with shear characterization of a cross-ply thermoplastic lamina using picture frame tests

The current research investigates characterization of soft composite materials used in the manufacture of combat helmets. The material system considered is a cross-ply unidirectional (UD) sheet comprised of ultrahigh molecular weight polyethylene (UHMWPE) fibers consolidated with a polyurethane (PUR) based matrix. This paper presents efforts toward characterization of the material’s shear behavior using the picture frame (a.k.a. trellis frame, shear frame, rhombus) test method and systematically investigates parameters influencing measurement of shear stiffness including sample arm geometry, forming temperature, strain rate, and mechanical conditioning. A specific emphasis is placed on the importance of arm geometry in the shear characterization. Overestimation of the force curve is found to result from interference of supporting arm material outside the central region of the test specimen. Removal of the excess arm material results in more accurate measurements of shear stiffness, which are subsequently available for input into FE models that simulate forming processes.     

Evaluating the performance of geosynthetic-reinforced unpaved roads using plate load tests

This study evaluates the performance of geosynthetic-reinforced unpaved road sections over soft subgrade using plate load test. The parameters investigated included the location and tensile modulus of geosynthetics, and the number of geosynthetic layers. Stress distribution on top of the subgrade layer and strain distribution along the geosynthetic reinforcements were also investigated. The test results indicated that geosynthetic reinforcement resulted in appreciable reduction of surface deformation and increase of bearing capacity. The test results also demonstrated the effects of geogrid arrangement/location on the performance of unpaved test sections, with double reinforcement location consistently yielded the best improvement. The definite trend of increasing Bearing Capacity Ratio (BCR) and reloading elastic modulus with increasing tensile modulus of geosynthetics was observed when geosynthetics were grouped according to aperture shape and polymer type. The BCR is defined as the ratio of the bearing capacity of reinforced unpaved sections to that of unreinforced unpaved section.     

Evaluating the susceptibility of steels to hydrogen embrittlement using statistical analyses

Delayed failure tests of hydrogen-charged specimens result in a large scatter of failure times and failure stresses, analogous to the brittle behaviour exhibited by ceramics. Because of the considerable variation in results, a large number of specimens have to be tested in order to gain an indication of the performance of a particular material; when two materials of similar susceptibility to hydrogen embrittlement are tested, interpretation of the results is often difficult. In the present investigation, seven similar steels were tested in the delayed failure mode to determine their relative susceptibilities to hydrogen embrittlement. These steels were of similar composition and microstructure and showed a low susceptibility to hydrogen embrittlement. The results were analysed using established statistical analysis methods, and by a modified statistical analysis which was developed to describe the failure behaviour. The results of the delayed failure tests and the statistical analyses are presented.