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81.
L. Rosenfeld 《Wear》1976,40(2):165-177
Experiments on the sliding wear phenomena of bearing materials with solid particles in the oil film have revealed that with a tin-aluminium alloy gas is released. However this did not occur with white metal or copper-lead. Gas was again released when clean oil was used. One analysis of the released gas by mass spectroscopy showed it to consist chiefly of air with a small percentage of hydrogen, several orders of magnitude higher than normally found in dry air.Gas is also released by scratching aluminium, zinc and a magnesium alloy in straight mineral lubricating oil, liquid paraffin, silicone oil as-received or dried, and also in glycerol and water. Copper, brass, white metal, mild steel and titanium showed very little or no gas evolution.The literature on the effect of hydrogen on rolling bearing life is briefly reviewed and the possible effect of hydrogen on sliding wear is discussed. 相似文献
82.
C Chabannon K Cornetta JP Lotz C Rosenfeld M Shlomchik S Yanovitch JP Marolleau G Sledge G Novakovitch EF Srour B Burtness J Camerlo G Gravis J Lee-Fischer C Faucher I Chabbert D Krause D Maraninchi B Mills L Kunkel F Oldham D Blaise P Viens 《Canadian Metallurgical Quarterly》1998,78(7):913-921
Seven chlorine-containing orcinol derivatives (2-8) and orcinol (9) have been isolated from diseased bulbs of the edible lily Lilium maximowiczii, and their structures have been elucidated. Six of the chlorinated orcinol derivatives (2, 4-8) showed antifungal activity. Because organochlorine compounds are rare in terrestrial higher plants, their biosynthetic origin was examined. These compounds were shown to be induced in intact bulb scales by UV irradiation or by inoculation with the pathogenic fungus Fusarium oxysporum f. sp. lilii. Biosynthetic studies suggested that these "natural organochlorine pesticides" are produced by enzymatic chlorination of orcinol (9) with chloroperoxidase and hydrogen peroxide, which are both induced in the plant tissue under stress conditions. 相似文献
83.
Modelling Temperature,Body Size,Prey Density,and Stream Gradient Impacts on Longitudinal Patterns of Potential Production of Drift‐Feeding Trout 下载免费PDF全文
In this study, we modelled idealized stream reaches using empirical hydrodynamic and bioenergetic parameters to predict how rainbow trout production depends on physical and biological variations across a downstream gradient, and we compared these downstream effects in a low and high‐gradient stream reach. We found that longitudinal production potential (i.e. net rate of energetic intake per 100 m of stream length) generally increased with increasing stream size when stream gradient was low. This was not the case, however, for high‐gradient streams, wherein maximum longitudinal production potential was associated with middle or low stream size (QMAD = 2.5 to 25 m3 s?1). Areal production potential (net rate of energetic intake per m2 of wetted stream bed) reached a maximum at low stream size (QMAD = 2.5 m3 s?1) with both high and low gradients. We also showed that high stream temperature and low drift density could potentially cause adult rainbow trout to be excluded from stream reaches with high flow. The models presented here have a stronger mechanistic basis for predicting fish production across heterogeneous stream environments and provide more nuanced predictions in response to variation in environmental features than their physical habitat‐based predecessors. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
84.
Abstract: In the last two decades, a wide range of robotic systems for interior construction tasks was being examined (mainly by research and development institutions around the world). A main parameter that differentiates between these systems is their level of autonomy. Reducing the level of autonomy of a given robotic system necessitates increasing auxiliary human work. The efficiency of the system as a whole (i.e., robot/s + operator/s + worker/s) must be examined in order to determine the proper balance between robots and human beings. This article presents the development of a methodology for evaluating a robotized construction task by examining and comparing various ways to share the work between robots and human operators and workers. The methodology is demonstrated by implementing it on two interior finishing tasks—block laying and wall painting. Testing these tasks included full-scale experiments. The detailed analyses of these two applications show the breakeven points of profitable robotic systems, depending on the combination of their own cost, the hourly cost of construction workers, and the expected hourly cost of construction-robot operators in a given labor market. The results lead to a better understanding of possible human-and-robot integration. In particular, this article provides researchers and developers of construction robotics with a systematic approach for evaluation and validation of various ideas prior to investing resources in actual prototypes. 相似文献
85.
A new concept is introduced to characterize and model the UV/H2O2 advanced oxidation process (AOP) in water. Similarto the Rct concept used to describe OH radical exposure per ozone dose, the ROH,UV concept is defined as the experimentally determined *OH radical exposure per UV fluence. ROH,UV was determined by examining the destruction of a probe compound, para-chlorobenzoic acid in four different waters: DI water and three natural waters. ROH,UV was found to be affected greatly by water quality, specifically background *OH radical scavenging, which competed forthe formed *OH radical with the probe compound, and background UV absorbance, which screened UV irradiation from the hydrogen peroxide. The ROH,UV values determined in the experiments using low-pressure Hg lamp were greater than those for the medium-pressure Hg lamp . Finally, the ROH,UV concept was utilized to calculate an overall scavenging factor for each water matrix, and this was successfully utilized in conjunction with the steady-state *OH radical model to improve the prediction of the oxidation of endocrine-disrupting compounds 17-alpha-ethinyl estradiol and 17-beta-estradiol in the natural waters. 相似文献
86.
The anatomy of odour wheels for odours of drinking water, wastewater, compost and the urban environment. 总被引:1,自引:0,他引:1
In the drinking water and air pollution fields, odour quality characterisation and intensity of each odour characteristic needs to be developed to evaluate the causes of the odours present. Drinking water quality characterisation has matured to the point where an "odour wheel" is described and the primary chemicals producing the odour are known and therefore a potential treatment can be defined from the odours reported. Sufficient understanding of the types of odorous compounds that can arise from wastewater and compost treatment processes and odours in the urban environment are starting to emerge. This article presents the anatomy of the odour wheels. It is hoped that the foundation of odour wheels will evolve as odour quality data are reported and linked with chemical causation. The compost and urban odour wheels are presented in print for the first time. 相似文献
87.
Horowitz YS Siboni D Oster L Livingstone J Guatelli S Rosenfeld A Emfietzoglou D Bilski P Obryk B 《Radiation protection dosimetry》2012,150(3):359-374
Low-energy alpha particle and proton heavy charged particle (HCP) relative thermoluminescence (TL) efficiencies are calculated for the major dosimetric glow peak in LiF:Mg,Cu,P (MCP-N) in the framework of track structure theory (TST). The calculations employ previously published TRIPOS-E Monte Carlo track segment values of the radial dose in condensed phase LiF calculated at the Instituto National de Investigaciones Nucleares (Mexico) and experimentally measured normalised (60)Co gamma-induced TL dose-response functions, f(D), carried out at the Institute of Nuclear Physics (Poland). The motivation for the calculations is to test the validity of TST in a TL system in which f(D) is not supralinear (f(D) >1) and is not significantly dependent on photon energy contrary to the behaviour of the dose-response of composite peak 5 in the glow curve of LiF:Mg,Ti (TLD-100). The calculated HCP relative efficiencies in LiF:MCP-N are 23-87% lower than the experimentally measured values, indicating a weakness in the major premise of TST which exclusively relates HCP effects to the radiation action of the secondary electrons liberated by the HCP slowing down. However, an analysis of the uncertainties involved in the TST calculations and experiments (i.e. experimental measurement of f(D) at high levels of dose, sample light self-absorption and accuracy in the estimation of D(r), especially towards the end of the HCP track) indicate that these may be too large to enable a definite conclusion. More accurate estimation of sample light self-absorption, improved measurements of f(D) and full-track Monte Carlo calculations of D(r) incorporating improvements of the low-energy electron transport are indicated in order to reduce uncertainties and enable a final conclusion. 相似文献
88.
Ashley Charlebois Greg Rosenfeld Brian Bressler 《Critical reviews in food science and nutrition》2016,56(8):1370-1378
Diet may be a successful part of the treatment plan for improving outcome in patients with inflammatory bowel disease (IBD). This study aimed to systematically review all published clinical trials evaluating the effects of a regular diet on symptoms of IBD. Three medical databases were searched for clinical trials evaluating an intervention that involved dietary manipulation using a regular diet on adults with IBD whose symptoms were objectively measured before and after the intervention. The most common types of regular diet interventions that we observed in the literature fell into the following three categories: low residue/low fiber diets, exclusion diets, or other specific diets. Of all included studies, the few that were of higher quality and that observed a statistically significant improvement in symptoms in the diet group compared to the control group fell under the exclusion diet group or the other specific diet group. We were able to identify several high quality clinical trials evaluating dietary manipulations on symptoms of IBD. Exclusion diets and the low FODMAP diet are two areas identified in this review that show promise for having therapeutic benefits for patients with IBD. 相似文献
89.
Low-loss waveguides fabricated in BK7 glass by high repetition rate femtosecond fiber laser 总被引:1,自引:0,他引:1
Eaton SM Ng ML Bonse J Mermillod-Blondin A Zhang H Rosenfeld A Herman PR 《Applied optics》2008,47(12):2098-2102
For the first time femtosecond-laser writing has inscribed low-loss optical waveguides in Schott BK7 glass, a commercially important type of borosilicate widely used in optical applications. The use of a variable repetition rate laser enabled the identification of a narrow processing window at 1 MHz repetition rate with optimal waveguides exhibiting propagation losses of 0.3 dB/cm and efficient mode matching to standard optical fibers at a 1550 nm wavelength. The waveguides were characterized by complementary phase contrast and optical transmission microscopy, identifying a micrometer-sized guiding region within a larger complex structure of both positive and negative refractive index variations. 相似文献
90.
Historically ignored or “treated,” clients' religious beliefs are being incorporated into psychotherapy because they influence client and therapist thinking and have potential to heal and harm. This paper examines how professional codes of ethics and research on religion-friendly therapeutic interventions and on helpful and harmful religious beliefs and practices provide direction in dealing with religious matters in psychotherapy. Ethical codes emphasize self-determination, beneficence, and nonmaleficence, which lead to different treatment decisions depending on how they are prioritized. The informed consent process and motivational interviewing have potential to ethically reduce harm and maximize benefits from the client's religious beliefs. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献