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排序方式: 共有245条查询结果,搜索用时 15 毫秒
1.
Paul W. Francisco Stacy Gloss Jonathan Wilson William Rose Yigang Sun Sherry L. Dixon Jill Breysse Ellen Tohn David E. Jacobs 《Indoor air》2020,30(1):147-155
Energy retrofits can reduce air exchange, raising the concern of whether indoor radon and moisture levels could increase. This pre/post-intervention study explored whether simple radon interventions implemented in conjunction with energy retrofits can prevent increases in radon and moisture levels. Treatment homes (n = 98) were matched with control (no energy retrofits or radon intervention) homes (n = 12). Control homes were matched by geographic location and foundation type. t-tests were used to determine whether post-energy retrofit radon and moisture level changes in treatment homes significantly differed from those in control homes. The radon interventions succeeded in preventing statistically significant increases in first floor radon using arithmetic (p = 0.749) and geometric means (p = 0.120). In basements, arithmetic (p = 0.060) and geometric (p = 0.092) mean radon levels statistically significantly increased, consistent with previous studies which found that basement radon levels may increase even if first floor levels remain unchanged. Changes in infiltration were related to changes in radon (p = 0.057 in basements; p = 0.066 on first floors). Only 58% of the change in infiltration was due to air sealing, with the rest due to weather changes. There was no statistically significant association between air sealing itself and radon levels on the first floor (p = 0.664). Moisture levels also did not significantly increase. 相似文献
2.
Rabya A. Lahmer David L. Jones Stacy Townsend Shenda Baker Arwel Prysor Williams 《International Journal of Food Science & Technology》2014,49(2):515-520
Here, we evaluated the impact of bacterial growth stage on the effect of chitosan‐arginine (Ch‐arg) on Escherichia coli O157:H7 cell numbers and metabolic activity within contaminated beef juice held at room temperature. Using a lux‐marked metabolic reporter strain of E. coli O157:H7, the results showed that Ch‐arg was most bioactive against cells in the lag phase and exponential phase. In comparison, there was a reduced, although still significant, inhibitory effect of Ch‐arg on the viability and metabolic activity of E. coli O157 held in stationary phase. Ch‐arg reduced, but did not eliminate E. coli O157 growth in the meat juice over 48 h. Based on the evidence presented here and elsewhere, we conclude that Ch‐arg can limit the growth and activity of food spoilage bacteria; however, it cannot completely eliminate bacterial contaminants originally present. Ch‐arg should therefore be viewed as a potentially protective measure rather than a biocidal agent that completely eliminates the risk of pathogen transfer in the food chain. 相似文献
3.
This article presents baseline data from 1120 employees across 10 worksites enrolled in a workplace physical activity intervention. The study provides new data on physical activity, sedentary behaviour, and health and highlights gender, geographical, job type and industrial sector differences. Sitting at work accounted for more than 60% of participants’ total daily sitting time on work days. Weekly and monthly hours worked, body mass index (BMI) and waist circumference were significantly higher for workers in the private sector compared to the public sector. Employees in sales and customer services had significantly higher BMI scores and significantly lower scores for workability index (WAI), job satisfaction, organisational commitment and job motivation, compared to other groups. This study provides further evidence that work is a major contributor to sedentary behaviour and supports the pressing need for interventions particularly targeting private sector industries and sales and customer service sectors.
Practitioner Summary: Work accounts for more than 60% of the daily sitting time. Private sector employees had higher BMIs than those in the public sector and employees in sales and customer services had higher BMIs and poorer health compared to other occupations, suggesting that these groups should be targeted in workplace interventions. 相似文献
4.
Stacy 《中国眼镜科技杂志》2018,(19)
正问:我未婚,即将而立之年,本科毕业后一直在一家眼镜外贸公司从事业务助理的工作,已经工作7年了,一直在默默出差,经常是加班早九晚九的作息,除了跟单,出体力搬箱验货,还需要经常和生产商打交道。我认为这么多年工作技能毫无增长,薪水是靠吃苦和时间积累的。目前因为公司发展工作量越来越大,公司没打算再增加人手,同时又倾向照顾有家庭的同事,所以现在出差任务越来越重,我有点儿承受不过来了。曾经找过老板提出想转岗文 相似文献
5.
Causes of chatter in a hot strip mill: Observations, qualitative analyses and mathematical modelling
Vladimir Panjkovi? Ronald Gloss John Steward Stephen Dilks Robert StewardGregory Fraser 《Journal of Materials Processing Technology》2012,212(4):954-961
Severe vibrations, known as chatter, occur often in both hot and cold rolling of steel. A recent chatter outbreak at the second stand of hot strip mill in Hastings, Australia, prompted an investigation into the causes of chatter by a literature review, the development and deployment of mathematical models, and a rigorous analysis of plant observations. The investigation suggests that the frictional conditions in the roll gap are the principal cause of chatter in this mill, though residual chatter marks on work rolls can occasionally cause it. The frictional conditions appear to be associated with the thickness and properties of oxide formed on rolls. 相似文献
6.
7.
Stacy A. Sommer Joseph R. Byrom Hanna D. Fischer Rajan B. Bodkhe Shane J. Stafslien Justin Daniels Carolyn Yehle Dean C. Webster 《Journal of Coatings Technology and Research》2011,8(6):661-670
Siloxane–polyurethane paints were formulated and characterized for coating properties and performance as fouling-release (FR)
marine coatings. Paints were formulated at 20 and 30 pigment volume concentrations with titanium dioxide, and aminopropyl-terminated
poly(dimethylsiloxane) (APT-PDMS) loadings were varied from 0 to 30% based on binder mass. The coatings were characterized
for water contact angle, surface energy (SE), gloss, and pseudobarnacle (PB) adhesion. The assessment of the FR performance
compared with polyurethane (PU) and silicone standards through the use of laboratory biological assays was also performed.
Biofilm retention and adhesion were conducted with the marine bacterium Cellulophaga lytica, and the microalgae diatom Navicula incerta. Live adult barnacle reattachment using Amphibalanus amphitrite was also performed. The pigmented coatings were found to have properties and FR performance similar to those prepared without
pigment. However, a higher loading of PDMS was required, in some cases, to obtain the same properties as coatings prepared
without pigment. These coatings rely on a self-stratification mechanism to bring the PDMS to the coating surface. The slight
reduction in water contact angle (WCA) and increase in pseudobarnacle release force with pigmentation suggests that pigmentation
slowed or interfered with the self-stratification mechanism. However, increasing the PDMS loading is an apparent method for
overcoming this issue, allowing for coatings having similar properties as those of clear coatings and FR performance similar
to those of silicone standard coatings. 相似文献
8.
9.
The Insect Telepresence project combines expertise from the robotics and human-computer interaction communities to create a robot exhibit that enables telepresence in scale. The underlying mission of this work is educational: to promote appreciation for insect life and small-scale complexity through exploration of live insect colonies. In this article we describe the robot hardware and software used to bring students face-to-face with insects. We also summarize the user-centered design process and formal HCI methods used to design and evaluate the Insect Telepresence robot. The complete working exhibit, now installed as a permanent robot-entomology station at the Carnegie Museum of Natural History, is presented in this paper in words and pictures. 相似文献
10.
Jue Tao Lim Borame Sue Dickens Ken Wei Tan Joel Ruihan Koo Annabel Seah Soon Hoe Ho Janet Ong Jayanthi Rajarethinam Stacy Soh Alex R. Cook Lee Ching Ng 《Journal of the Royal Society Interface》2021,18(182)
Over 105 million dengue infections are estimated to occur annually. Understanding the disease dynamics of dengue is often difficult due to multiple strains circulating within a population. Interactions between dengue serotype dynamics may result in complex cross-immunity dynamics at the population level and create difficulties in terms of formulating intervention strategies for the disease. In this study, a nationally representative 16-year time series with over 43 000 serotyped dengue infections was used to infer the long-run effects of between and within strain interactions and their impacts on past outbreaks. We used a novel identification strategy incorporating sign-identified Bayesian vector autoregressions, using structural impulse responses, historical decompositions and counterfactual analysis to conduct inference on dengue dynamics post-estimation. We found that on the population level: (i) across-serotype interactions on the population level were highly persistent, with a one time increase in any other serotype associated with long run decreases in the serotype of interest (range: 0.5–2.5 years) and (ii) over 38.7% of dengue cases of any serotype were associated with across-serotype interactions. The findings in this paper will substantially impact public health policy interventions with respect to dengue. 相似文献