Papers by Keyword: Tolerance

Abstract: Rhodococcus erythropolis S43 is an actinobacterium isolated from an arsenic-contaminated soil sample, collected from an old smelter site, including an arsenic smelter, in Germany. This strain has unique features as compared to the other members of the species, namely resistance to elevated concentrations of arsenic. Here, we present the microbiological features and genomic properties of this biotechnologically relevant strain. The 6,812,940 bp draft genome is arranged into 264 scaffolds of 848 contigs. It possesses 62.5% of CG content and comprises 6,040 coding sequences and 49 tRNA genes. Bioinformatic genome analysis showed the presence of arsenic-resistance genes. A complete ars operon was found containing the arsACDR cluster coding for ArsA (efflux pump ATPase), ArsC (arsenate reductase), ArsD (chaperone) and ArsR (ars operon regulator). Our results show that the arsC mRNA level significantly increased in response to arsenite and arsenate exposure, suggesting its involvement in the arsenic resistance phenotype of strain S43. In addition, this strain showed to have a plethora of genes coding for proteins involved in oxidative-stress response, including catalase, super-oxide dismutase, glutathione peroxidase-related genes, thioredoxin and thioredoxin reductase, suggesting it is highly tolerant to oxidative conditions. Finally, genes for radiation resistance, biodesulfurization, and oil and phenol degrading pathways were also detected. Altogether this data make R. erythropolis S43 a good candidate microorganism for bioremediation of highly contaminated environments and other industrial applications.

Abstract: The chloride tolerance of three Fe (II)- and sulfur-oxidising thermophiles and the effect of chloride on metals extraction from mineral sulfides were studied. Initially, 10-day bioleaching tests (60 °C) were conducted using pyrite (FeS₂), chalcopyrite (CuFeS₂) or pentlandite ((Ni,Fe)₉S₈) concentrates as substrate in basal salts medium (BSM), and the activities of Sulfolobus (S.) metallicus, Acidianus (A.) brierleyi and Metallosphaera (M.) hakonensis were compared. Fe (II) oxidation, as indicated by an increase in oxidation reduction potential (ORP), was observed in all combinations except A. brierleyi growing on chalcopyrite. The presence of added NaCl resulted in lower ORP after 10 days of bioleaching in all cases. In ancillary tests using BSM-Fe (II) growth medium with added NaCl it was found that cell counts at the end of Fe (II) biooxidation provided the most reliable estimate of tolerance to NaCl. On this basis, the rank order of salt tolerance is S. metallicus >>>A. brierleyi > M. hakonensis.

Abstract: Due to the complexity of the product development increasing in Automotive Industry, the key characteristics of the product or manufacturing process become more and more important in the product life cycle. The importance of identification of key characteristics is considerably because of the impact that can occur in costs, product reliability, environment and safety. Each key characteristic is determined according to customer requirements and is controlled and monitored during production phase in order to secure the quality of the product. The identification of key characteristics is performed by a team, after the analysis of customer requirements, norms and regulations requirements and international organization requirements. The key characteristics are marked by a special marking and should be ensured a traceability of key characteristics through impacted documents (drawings, FMEAs (Failure Mode and Effect Analysis), control plan, work instructions etc.).

Abstract: The use of parallel manipulators in industrial is growing. Among key advantages of parallel manipulators versus their serial counterparts, is their improved end-effector positioning accuracy than open-loop mechanism. However, undesirable dimensional tolerance and joint clearance can decrease the positioning accuracy of the end-effector. In this article, Taguchi method is applied to a 3-PSP parallel manipulator to determine how dimensional tolerance and joint clearance affects the accuracy of its end effector. Because of random nature of dimensional tolerance, it is assumed that actual value of all kinematic parameters are normally distributed. Taguchi method is then used and effect of tolerance on accuracy for each of the manipulator kinematics parameters is obtained. Finally, a tolerance set resulting in best accuracy is predicted by the Taguchi method. This tolerance is verified with a new set of experiment.

Abstract: The paper discusses the problems on accurate assembly of large-sized cylinder segments by illustrating an example of the geokhod assembly. The mathematical expressions for determining deviations of sector profile from the nominal circle of the shell depending on the radius of sector, its tolerances and the location of supports. The influence of the distance between the supports on the profile deviation is shown. Solutions to minimize the profile deviation are given.

Abstract: The primary goal of concurrent engineering is to minimize the time spend and to reduce quality problems encountered between a product's conception and customer use, thereby minimizing cost and maximizing product quality. Tolerance is an important index of product design and manufacture. Although they are small as compared with part dimensions, tolerances can propagate and accumulate in an assembly affecting the product assimilability. Moreover, tolerance is inevitable because manufacturing exactly equal parts is known to be impossible. This paper presents a brief review of statistical tolerance and clearance analysis for the assembly, and proposes a method of tolerance analysis by a leading commercial computer-aided tolerance (CAT) analysis system, VisVSA. This method can ensure assembly precision requirements, and design optimally tolerance distribution based on Monte Carlo simulation, take a example of brake assembly to detailed introduce the use of this method. The purpose of this article is expected to make the following contributions: (i) to help the designers to evaluate products for assimilability, (ii) to provide a new perspective to tolerance problems, and (iii) to provide a tolerance analysis tool, VisVSA, which can be incorporated into a CAD or solid modeling system.

Abstract: The paper also says about practical measuring geometrical deviations by commonly used tools. Also deals with an analysis of geometric deviations, reasons of their generation and provides their brief description. It points at ways and abilities of measuring shape deviations by means of contact and contactless measuring methods and deals with errors which can affect results of measuring. It evaluates and analyses ability of measuring by various devices. It shows a review of individual measured values and thus provides a view of efficiency, simplicity and accuracy of individual measuring devices and measuring methods.

Abstract: Soft fault diagnosis and tolerance are two challenging problems in analog circuit fault diagnosis. This paper proposes approaches to solve these two problems. First, a complex field modeling method and its theoretical proof are presented. This fault modeling method is applicable to both hard (open or short) and soft (parametric) faults. It is also applicable to either linear or nonlinear analog circuits. Then, the parameter tolerance is taken into consideration. A frequency selection method is proposed to maximize the difference between the faults fault signature. Hence, the aliasing problem arise from tolerance can be mitigated. The effectiveness of the proposed approaches is verified by simulated results.

Abstract: Soft fault diagnosis and tolerance are two challenging problems in linear analog circuit fault diagnosis. To solve these problems, a phasor analysis based fault modeling method and its theoretical proof are presented at first. Second, to form fault feature data base, the differential voltage phasor ratio (DVPR) is decomposed into real and imaginary parts. Optimal feature selection method and testability analysis method are used to determine the optimal fault feature data base. Statistical experiments prove that the proposed fault modeling method can improve the fault diagnosis robustness. Then, Multi-class support vector machine (SVM) classifiers are used for fault diagnosis. The effectiveness of the proposed approaches is verified by both simulated and experimental results.

Abstract: Air pollution tolerance index (APTI) is used by landscapers to select plant species tolerant to air pollution. The present study evaluated APTI for selected ten common plant species, which were fumigated with 40 ppb sulfur dioxide (SO₂) gas for 210 days. The APTI is used by landscapers to select plant species tolerant to air pollution. In order to develop the usefulness of plants as indicators requires an appropriate selection of plant species, which is of utmost importance in specific situations. Four biochemical parameters, including ascorbic acid content, leaf extract pH, total leaf chlorophyll, and leaf relative water content were used to develop an APTI. The results showed that plants have the potential to serve as excellent quantitative and qualitative indices of pollution. Since biomonitoring of plants is an important tool by which to evaluate the impact of air pollution on plants, Diospyros maritime is a good selection as an index of SO₂ pollution. The order of tolerance in SO₂ as Diospyros maritime > Diospyros discolor > Decusscarpus nagi > Cerbera manghas > Delonix regia > Melia azedarach > Machilus zuihoensis > Ficus sepitca > Erythrina variegate > Messerschmidia argentea.