186 research outputs found
Numerical solution of functional integral equations by the variational iteration method
AbstractIn the present article, we apply the variational iteration method to obtain the numerical solution of the functional integral equations. This method does not need to be dependent on linearization, weak nonlinearity assumptions or perturbation theory. Application of this method in finding the approximate solution of some examples confirms its validity. The results seem to show that the method is very effective and convenient for solving such equations
A fault-tolerant control architecture for different battery topologies in electric vehicles
Abstract: In this paper a variety of battery configuration topologies for electrified vehicles are investigated with regard to reliability and expected lifetime along with the possibility of applying active fault detection to provide early warnings for the driver. Different configurations are investigated ranging from a simple single serial string of battery cells providing only the lowest level of fault tolerance, to a highly elaborate and still practically relevant triple string configuration providing fault detection and reconfiguration possibilities as well as repair. All configurations are analyzed with regard to the associated reliability profile assuming non-ageing cell failure model. A novel method for active early fault detection is presented based on encoding faults into a parametric dynamic cell model, where parameters are continuously estimated under the influence of an auxiliary test signal designed to optimize parametric sensitivity. Finally reliability profiles for all investigated configurations are compared mutually and with standard requirements on the basis of mean time to failure statistics
Passive Fault Tolerant Control of Piecewise Affine Systems Based on H Infinity Synthesis
International audienceIn this paper we design a passive fault tolerant controller against actuator faults for discretetime piecewise affine (PWA) systems. By using dissipativity theory and H analysis, fault tolerant state feedback controller design is expressed as a set of Linear Matrix Inequalities (LMIs). In the current paper, the PWA system switches not only due to the state but also due to the control input. The method is applied on a large scale livestock ventilation model
Feasibility study of recycling and converting acidic sludge to bitumen in used motor oil refining industries
Background and Aims: Thousand tons of acidic sludge is produced daily as by-product in the used motor oil refining industries. The acidic sludge contains unsaturated compounds which are non-polar and asphaltene. The objective of this study was performance improvement of acidic sludge by using the additives (bentonite, polymer SBS, sodium hydroxide and the lime) so that recovery to bitumen.Materials and Methods: The polymer styrene - butadiene - styrene (SBS) is bitumen modifier as one of the elastomer - thermoplastic with weight percentages (2 to 4 percent), bentonite due to the chemical structure as fillers, stabilizers and agent concentration with weight percentages (1,2,4,6,8,10) and lime and sodium hydroxide were used to decreasing acidity rate of acidic sludge and promoting the role of bentonite stability in bitumen with ratios equal (1 to 5 g) were mixed with acidic sludge of industry (samples 50 g) and their effect on the acidic sludge was investigated.Results: Evaluation of studies indicated that because of increasing acidic sludge softening point, temperature from 25 to 48 oC , decrease weight loss from 3% to 1.25, promoting the penetration degree to 230 mm, Frass breaking point to -7 and penetration index (PI) to the degree standard set (+1), the acidic sludge properties and performance were modified. The measurement of last three parameters was unavailable in primary sludge.Conclusion: Environmental and health hazards of acidic sludge will be decreases by treatment and neutralization. Also obtained products can be used in the building and road construction according to its specific bitumen criteria and characteristics.Key words: Recovery - Acidic sludge - Used motor oi
Application of the Variational Iteration Method for Solving Differential -Difference Equations
Abstract In this paper, an application of variational iteration method is applied to solve differential -difference equations (DDE
Examining the effects of behavioral biases of investors on Tehran Stock Exchange efficiency using trends and consistency in firms’ financial performance during 1997-2006
The present study investigates the effects of behavioral biases on the efficiency of Tehran stock exchange. In fact, these biases are the mistakes that individuals make while making financial decisions. The methodology of this research is that firms with financial information during 1997 to 2006 that have also been active on the stock exchange have been classified based on two criterions of operating profit/per share and earnings per share, then, the return of these firms was calculated in the first period and compared to their return in the second period. Therefore, it will be clear that the companies’ financial performance trend has been effective on the behavioral biases of investors and consequently on their extreme reactions towards the published information. Therefore, the process of the stock return changes can be predicted in the coming period. As a result, this hypothesis is an evidence of market inefficiency and predictability of financial behavioral theories. On the other hand, this research does not offer sufficient and strong evidences on the effect of consistency in the financial performance process and also the presence of compatible and incompatible signs in companies’ financial performance on the market predictability. Thus, in this case, it is not possible to admit the effect of behavioral biases on the predictability and thus market efficiency.
Keywords: behavioral finance, financial performance, behavioral bias, representation, conservatism. JEL Classification: G02, G23, M4
Osteology of the posterior vertebral column and caudal skeleton of marine amphibious gobies (mudskippers) (Teleostei: Gobioidei)
Mudskippers are amphibious gobies (Teleostei: Gobioidei, Oxudercinae) that have served as models for the specialised physiology and behaviour of fishes out of water. In this study, a comparative analysis of the posterior vertebral column and the caudal skeleton of ten mudskipper species was conducted on the basis of X‐ray imaging. The species considered were Apocryptes bato, Apocryptodon madurensis, Boleophthalmus dussumieri, Oxuderces dentatus, Periophthalmodon freycineti, Pn. schlosseri, Periophthalmus novemradiatus, Ps. waltoni, Pseudapocryptes borneensis, and Scartelaos tenuis. For the osteological description the new term 'modified caudal vertebra' is used for all those vertebrae that display visibly modified neural and/or haemal spines compared to the spines of a 'usual' caudal vertebra, but are not involved in the support of caudal rays. The results reveal that the most terrestrial forms (Pn. freycineti, Pn. schlosseri, Ps. novemradiatus, Ps. waltoni) possess distinct traits that are seldom found in the other species. Among these features are (a) the existence of at least two modified caudal vertebrae (also present in S. tenuis), (b) a particularly close, dovetailing association between the neural spines of the preural vertebrae two and three (restricted to Ps. novemradiatus and Ps. waltoni), and (c) thickening and shortening of the ventralmost principal caudal rays (also present in B. dussumieri and S. tenuis). These findings support the idea that the posterior caudal vertebrae and caudal skeleton of the mentioned species are modified to enhance locomotion on land. Moreover, a relationship between character development and degree of terrestrial adaptation is probable, as all three traits are most pronounced in Ps. waltoni, which correlates with its strikingly high level of adaptation to amphibious life. A further aspect of this study is that the newly recognized skeletal structures have good fossilization potential and could therefore facilitate recognition of fossil species of mudskippers, which are currently unknown
Evaluation of [67Ga]-insulin for insulin receptor imaging
BACKGROUND: Radiolabelled human recombinant insulin can
be used for the imaging of insulin receptors in some tumours
where FDG has natural uptake and diminishes the value of its
imaging.
MATERIAL AND METHODS: Insulin was successively labelled
with [67 Ga]-gallium chloride after conjugation with freshly prepared
cyclic DTPA-dianhydride (HPLC radiochemical purity
assay > 96%) followed by biodistribution studies in normal rats,
white blood cell labelling and preliminary SPECT studies.
RESULTS: In vitro studies demonstrated the retention of radiolabelled
insulin receptor affinity using freshly prepared human
white blood cells at different blood sugar conditions.
Preliminary in vivo studies in a normal rat model was performed
to determine the biodistribution of the radioimmunoconjugate
at up to 44 h. SPECT images revealed high uptake
of the liver.
CONCLUSION: Radiolabelled insulin is stable enough to be
used in biological studies in order to image insulin receptors in
diabetic conditions as well as possible tumour imaging applications.
The data was consistent with other radiolabelled insulin
studies
- …