Full scale investigation of GCL damage mechanisms in small earth dam retrofit applications under earthquake loading

This paper reports results of full scale testing to further explore potential GCL damage mechanisms in earth dam retrofit applications in seismically active areas; in particular, to a) investigate whether shear displacements could reduce the magnitude of GCL panel overlap during earthquake shaking; b) explore the influence of gravel particles on GCL thickness at localised point of contact; and c) observe the consequences of an accidental exposure of an uncovered GCL to short duration rainfall in terms of moisture content and effects during subsequent compaction. The results of these experiments indicate that even under severe shaking no movements were detected at the GCL panel overlap. Whereas gravel particles were observed to locally reduce the thickness of the GCL to 2.2 mm, no plowing of the particle into the GCL occurred due to a lack of shear displacement at the interface, resulting in no localised internal erosion through the barrier. Furthermore, hydration of GCL panels during construction due to surface wetting was observed to result in a state of hydration less than its post-construction state. These results indicate that although each of the three GCL damage mechanisms cannot be ruled out to ever be relevant in practice, the performance of the GCL retrofitted earth dam tested was satisfactory under even severe Level 2 earthquake shaking, and suggests that the retrofitting of small earth dams with GCLs is a promising strategy to improve their static and seismic resistance.     

Companies

Net earnings after pre-tax profits. Profiles include: Anadarko Petroleum, Chevron Texaco, Conoco Phillips, Exxon Mobil, Occidental, Schlumberger, YPF SA, EnCana Corporation, Imperial Oil, Petroleo Brasileiro, Total SA, E.ON, ENI, Repsol, Ecopetrol SA, Norsk Hydro, Statoil, Devon Energy Corporation. BP, Shell, BHP Billiton, CNOOC, Sinopec and PetroChina. Updated on a monthly basis.     

Companies

Net earnings after pre-tax profits. Profiles include: Anadarko Petroleum, Chevron Texaco, Conoco Phillips, Exxon Mobil, Occidental, Schlumberger, YPF SA, EnCana Corporation, Imperial Oil, Petroleo Brasileiro, Total SA, E.ON, ENI, Repsol, Ecopetrol SA, Norsk Hydro, Statoil, Devon Energy Corporation. BP, Shell, BHP Billiton, CNOOC, Sinopec and PetroChina. Updated on a monthly basis.     

带耐火衬里高温反应器密封锥结构的设计

耐火衬里及支撑结构设计的可靠性是保证高温反应器壳体温度小于设计温度的关键因素。针对耐火衬里结构失效导致反应器壳体温度超过设计温度的问题,提出了一种双金属焊接的密封锥结构。该结构具有支撑金属衬里的作用以及将耐火材料与金属衬里之间的膨胀空间分割成多个密闭空间以阻止高温气体的流动,进而提高隔热可靠性。采用ANSYS软件中APDL语言建立了密封锥连接结构的有限元模型,通过研究密封锥不同角度以及厚度对计算结果的影响,得出了密封锥的最佳结构参数,并满足ASME标准的应力强度评定要求。模拟结果可为此类高温反应器耐火衬里结构的设计提供参考依据。     

Companies

Net earnings after pre-tax profits. Profiles include: Anadarko Petroleum, Chevron Texaco, Conoco Phillips, Exxon Mobil, Occidental, Schlumberger, YPF SA, EnCana Corporation, Imperial Oil, Petroleo Brasileiro, Total SA, E.ON, ENI, Repsol, Ecopetrol SA, Norsk Hydro, Statoil, Devon Energy Corporation. BP, Shell, BHP Billiton, CNOOC, Sinopec and PetroChina. Updated on a monthly basis.     

Study protocol and baseline results for a quasi-randomized control trial: An investigation on the effects of ergonomic interventions on work-related musculoskeletal disorders,quality of work-life and productivity in knowledge-based companies

IntroductionWork-related musculoskeletal disorders (WMSDs) are the major causes of lost workdays, increased costs, and occupational diseases in all countries. The prevalence of WMSDs among the workers in small and medium-sized enterprises in Iran was reported as 73%. This paper aimed to describe the design of an interventional study to investigate the effects of ergonomic interventions on work-related musculoskeletal disorders, quality of work-life, and productivity among office workers of knowledge-based companies and introduce the results obtained from the baseline survey.Methods/designIt was a quasi-randomized control trial study on 313 participants with four parallel groups including ergonomic training intervention; management training and work changes intervention; ergonomic training, management training and work changes intervention; and non-interventional control group. The primary outcome was WMSDs, and the secondary outcomes were occupational stress factors, quality of work-life, and productivity. All primary and secondary outcomes were measured before the interventions, one, three, and six months after the interventions.ResultsAt this phase of study only baseline results were reported. 328 participants, with a mean age of 31.97 years (SD = 5.39), completed the baseline survey and entered the study. The highest prevalence of musculoskeletal disorders was found in neck (52.13%), right shoulder (41.16%) and right forearm (37.2%), respectively.ConclusionErgonomic interventions were conducted based on baseline data of the participants at individual and management levels. The focus of training program interventions was to reduce musculoskeletal disorders in upper limbs; in management training and work changes program, the focus was to increase social support.Trial registrationIRCT registration number: IRCT20181204041840N1 (date of registration: 2019-02-05).     

Companies

Net earnings after pre-tax profits. Profiles include: Anadarko Petroleum, Chevron Texaco, Conoco Phillips, Exxon Mobil, Occidental, Schlumberger, YPF SA, EnCana Corporation, Imperial Oil, Petroleo Brasileiro, Total SA, E.ON, ENI, Repsol, Ecopetrol SA, Norsk Hydro, Statoil, Devon Energy Corporation. BP, Shell, BHP Billiton, CNOOC, Sinopec and PetroChina. Updated on a monthly basis.     

高硬度环保耐蚀柴油机气缸套的研制

在缸套表面进行镍磷复合镀强化处理,可以提高湿式内燃机缸套耐腐蚀性能,但会增加产品的成本。研究了在普通贝氏体气缸套材料基础上去掉贵重金属镍,调整其他成分比例,在确保材料性能不变的前提下,降低产品的成本。结果表明,配合表面强化处理,缸套硬度高、耐腐蚀强、生产成本低,并可以延长发动机寿命。     

Induction of adaptive response <i>in utero </i>by ionizing radiation: A radiation quality dependent phenomenon

Investigation on possible induction of adaptive response (AR) by high-liner energy transfer (LET) particle radiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed in utero. This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ions against low-LET X-ray radiation-induced detrimental effects on fetal mice. Total body irradiation of pregnant C57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiation on gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation. The monoenergetic beams of carbon, silicon and iron with the LET values of about 15, 55, and 200 KeV/μm, respectively, were examined. Significant suppression by the priming radiation of the detrimental effects (fetal death, malformation, or low body weight) was used as the endpoints for judgment of a successful AR induction on gestation day 18. Existence of AR was not observed. On the other hand, the priming dose of high-LET particle radiation, in some cases, even increased the detrimental effects induced by the challenge dose from low-LET X-ray radiation. Although existence of AR induced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivo was demonstrated, the present study did not suggest that low dose of high-LET particle radiation could induce an AR in fetal mice in utero under the setup of our experimental system.     

Numerical study of strain development in high-density polyethylene geomembrane liner system in landfills using a new constitutive model for municipal solid waste

Tensile strain development in high-density polyethylene (HDPE) geomembrane (GMB) liner systems in landfills was numerically investigated. A new constitutive model for municipal solid waste (MSW) that incorporates both mechanical creep and biodegradation was employed in the analyses. The MSW constitutive model is a Cam-Clay type of plasticity model and was implemented in the finite difference computer program FLAC?. The influence of the friction angle of the liner system interfaces, the biodegradation of MSW, and the MSW filling rate on tensile strains were investigated. Several design alternatives to reduce the maximum tensile strain under both short- and long-term waste settlement were evaluated. Results of the analyses indicate that landfill geometry, interface friction angles, and short- and long-term waste settlement are key factors in the development of tensile strains. The results show that long-term waste settlement can induce additional tensile strains after waste placement is complete. Using a HDPE GMB with a friction angle on its upper interface that is lower than the friction angle on the underlying interface, increasing the number of benches, and reducing the slope inclination are shown to mitigate the maximum tensile strain caused by waste placement and waste settlement.