1,721,004 research outputs found
Biomechanical model of human on seat with backrest for evaluating ride quality
No full textThis study is to develop a biomechanical model of human on a seat with backrest for evaluating the vehicular ride quality. In describing the human body motion, four biomechanical models are discussed: 1 DOF (degree-of-Freedom) model mainly describes the z-axis motion of the hip, and 2 and 3 DOF models describe the z-axis motion of the hip and head while 9 DOF model we proposed includes the motions of the floor, hip, back, and head to describe the whole-body vibration in a sitting posture with backrest support. To validate the proposed model, we measured the accelerations at the hip, back, and head of 10 subjects with the floor under vertical vibration excitation. From this measurement, three transmissibilities for each subject were obtained. We also measured the parameters including the material property of seat cushion. joint positions of human body, and the contact positions between human body and seat, while the other parameters such as stiffness and damping at the hip, back, and head were determined by matching the model transmissibilities to the experimental ones. The 9 DOF model shows good matching for transmissibility at the both first 4.2 Hz mode and second 7.7 Hz mode. The comparison of the experimental data with those simulated using 1, 2, 3, and 9 DOF models shows that 9 DOF model provides the best description of the experimental results
Influence of phenol on biodegradation of p-nitrophenol by freely suspended and immobilized Nocardioides sp NSP41
No full textThe effect of the presence of an alternate toxic compound (phenol) on the p-nitrophenol (PNP)-degrading activity of freely suspended and calcium alginate immobilized Nocardioides sp. NSP41 was investigated. In the single substrate experiments, when the concentration of phenol and PNP was increased to 1400 mg l(-1) and 400 mg l(-1), respectively, the initial cell concentrations in the freely suspended cell culture should be higher than 1.5 g dry cell weight l(-1) for complete degradation. In the simultaneous degradation experiment, when the initial concentration of phenol was increased from 100 to 400 mg l(-1), the specific PNP degradation rate at the concentration of 200 mg l(-1) was decreased from 0.028 to 0.021 h(-1). A freely suspended cell culture with a high initial cell concentration resulted in a high volumetric degradation rate, suggesting the potential use of immobilized cells for simultaneous degradation. In the immobilized cell cultures, although simultaneous degradation of PNP and phenol was maintained, the specific PNP and phenol degradation rate decreased. However, a high volumetric PNP and phenol degradation rate could be achieved by immobilization because of the high cell concentration. Furthermore, when the immobilized cells were reused in the simultaneous degradation of PNP and phenol, they did not lose their PNP- and phenol-degrading activity for 12 times in semi-continuous cultures. Taken together, the use of immobilized Nocardioides sp. NSP41 for the simultaneous degradation of PNP and phenol at high concentrations is quite feasible because of the high volumetric PNP and phenol degradation rate and the reusability of immobilized cells
Effect of soil moisture on bioremediation of chlorophenol-contaminated soil
No full textA chlorophenol-contaminated soil was tested for the biodegradability in a semi-pilot scale microcosm using indigenous microorganisms. More than 90% of 4-chlorophenol and 2,4,6-trichlorophenol, initially at 30 mg kg(-1), were removed within 60 days and 30 mg pentachlorophenol kg(-1) was completely degraded within 140 days. The chlorophenols were degraded more effectively under aerobic condition than under anaerobic condition. Soil moisture had a significant effect with the slowest degradation rate of chlorophenols at 25% in the range of 10-40% moisture content. At 25-40%, the rate of chlorophenol degradation was directly related to the soil moisture content, whereas at 10-25%, it was inversely related. Limited oxygen availability through soil agglomeration at 25% moisture content might decrease the degradation rate of chlorophenols
Nocardioides nitrophenolicus sp. nov., a p-nitrophenol-degrading bacterium
No full textA p-nitrophenol-degrading bacterial strain was isolated from industrial wastewater. This strain (NSP41(T)) was identified as a member of the genus Nocardioides from chemotaxonomic characterizations and phylogenetic inference based on 16S rDNA sequence analysis. The G+C content is 71.4 mol%. The diamino acid in the cell-wall peptidoglycan is LL-diaminopimelic acid. The predominant menaquinone is MK-8(H-4). The cellular fatty acid profile is similar to those of Nocardioides species. 16S rDNA sequence analysis show that strain NSP41(T) is the most related to Nocardioides simplex strains with a level of nucleotide similarity of 98.6%. The levels of 16S rDNA similarity between strain NSP41(T) and other Nocardioides species ranged from 93.8 to 95.1%. This organism is distinguishable from some other Nocardioides species as well as N. simplex strains by DNA-DNA relatedness data. This organism is different from N. simplex strains in some phenotypic characteristics. Therefore, on the basis of the data presented, a new species of the genus Nocardioides, Nocardioides nitrophenolicus, is proposed. The type strain of the new species is strain NSP41(T) (= KCTC 0457BP(T))
Rhodococcus koreensis sp nov., a 2,4-dinitrophenol-degrading bacterium
No full textA 2,4-dinitrophenol-degrading bacterial strain, DNP505(T), which was isolated from an industrial wastewater, was taxonomically studied by a polyphasic approach using phenotypic, chemotaxonomic and genetic methods. Strain DNP505(T) has a cell wall of chemotype IV containing meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone is MK-8(H-2). Mycolic acids contain 43-53 carbon atoms. Strain DNP505(T) has a cellular fatty acid profile containing straight-chain saturated, unsaturated and 10-methyl-branched fatty acids and has C-16:0 as the major fatty acid. The DNA G+C content is 66 mol%. Strain DNP505(T) formed a coherent cluster with Rhodococcus species in a phylogenetic inference based on 16S rDNA sequences. Interestingly, strain DNP505(T) was found to have two types of 16S rDNA sequence, which showed 10 bp sequence differences (99.3 % nucleotide similarity). Its differences in some phenotypic characteristics and its genetic distinctiveness indicate that strain DNP505(T) is separate from Rhodococcus species described previously. It is therefore proposed that strain DNP505(T) should be placed in the genus Rhodococcus as a new species, Rhodococcus koreensis. The type strain of the new species is strain DNP505(T) (= KCTC 0569BP(T) = JCM 10743(T))
Wafer-scale antireflective protection layer of solution-processed TiO2 nanorods for high performance silicon-based water splitting photocathodes
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Anaerobic degradation of pyrrolidine and piperidine coupled with nitrate reduction
No full textBiodegradability of secondary amines (pyrrolidine, piperidine, piperazine, morpholine, and thiomorpholine) under anaerobic conditions was examined in microbial consortia from six different environmental sites. The consortia degraded pyrrolidine and piperidine under denitrifying conditions. Enrichment cultures were established by repeatedly sub-culturing the consortia on pyrrolidine or piperidine in the presence of nitrate. The enrichments strictly required nitrate for the anaerobic degradation and utilized pyrrolidine or piperidine as a carbon, nitrogen, and energy source for their anaerobic growths. The anaerobic degradation of pyrrolidine and piperidine reduced nitrate to nitrogen gas, indicating that these anaerobic degradations were coupled with a respiratory nitrate reduction. (C) 2002 Elsevier Science Ltd. All rights reserved
Isolation and characterization of a novel Pseudomonas sp., strain YG1, capable of degrading pyrrolidine under denitrifying conditions
No full textA denitrifying bacterium, strain YG1, capable of degrading pyrrolidine under denitrifying conditions, was isolated. On the basis of phenotypic and phylogenetic characteristics, it was identified as a member of the genus Pseudomonas. During the anaerobic degradation of pyrrolidine, YG1 reduced a stoichiometric amount of nitrate to nitrogen gas, demonstrating that the degradation of pyrrolidine is coupled with respiratory nitrate reduction. YG1 also degraded pyrrolidine with a higher degradation rate under aerobic conditions than under denitrifying conditions. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Microbiological Societies
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