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This paper addresses an efficient modification method that eliminates the undesirable effects of strains due to various non-conforming modes so that the non-conforming element can pass the patch test unconditionally. The scheme is...
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This paper addresses an efficient modification method that eliminates the undesirable effects of strains due to various non-conforming modes so that the non-conforming element can pass the patch test unconditionally. The scheme is incorporated in the element formulation to establish new types of non- conforming hexahedral elements designated as NHx and NVHx for the regular element and variable node element, respectively. Non-conforming displacement modes are selectively behavior of the ordinary (conforming)element displacement assumptions to improve the bending behavior of the distorted solid element.
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The numerous opportunities for effect modifications pose a major challenge in ergonomic intervention research. Even studies in systematic reviews that are assessed as being of high quality generally lack any proper consideration o...
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The numerous opportunities for effect modifications pose a major challenge in ergonomic intervention research. Even studies in systematic reviews that are assessed as being of high quality generally lack any proper consideration of the potential effect modifiers. We have developed a method for effect modifier assessment (EMA) in intervention research. The EMA method uses a participatory workshop consisting of representatives from all occupational groups in the investigated organization. The workshop identifies both intervention and modifier events. These are categorized into themes, then analyzed and evaluated for their potential effects on the investigated outcomes. The overall impact of the pooled modifier themes is finally estimated in relation to the estimated impact of the intervention events. In the present study, the EMA method was tested in two cases. The findings suggest that it provides information that strengthens inferences about the impact of the investigated ergonomic interventions. Further evaluation of the method is recommended.
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Researchers conducting observational studies need to consider 3 types of biases: selection bias, information bias, and confounding bias. A whole arsenal of statistical tools can be used to deal with information and confounding bia...
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Researchers conducting observational studies need to consider 3 types of biases: selection bias, information bias, and confounding bias. A whole arsenal of statistical tools can be used to deal with information and confounding biases. However, methods for addressing selection bias and unmeasured confounding are less developed. In this paper, we propose general bounding formulas for bias, including selection bias and unmeasured confounding. This should help researchers make more prudent interpretations of their (potentially biased) results.
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Heterogeneous exposure associations (HEAs) can be defined as differences in the association of an exposure with an outcome among subgroups that differ by a set of characteristics. In this article, we intend to foster discussion of...
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Heterogeneous exposure associations (HEAs) can be defined as differences in the association of an exposure with an outcome among subgroups that differ by a set of characteristics. In this article, we intend to foster discussion of HEAs in the epidemiologic literature and present a variant of the random forest algorithm that can be used to identify HEAs. We demonstrate the use of this algorithm in the setting of the association between systolic blood pressure and death in older adults. The training set included pooled data from the baseline examination of the Cardiovascular Health Study (1989-1993), the Health, Aging, and Body Composition Study (1997-1998), and the Sacramento Area Latino Study on Aging (1998-1999). The test set included data from the National Health and Nutrition Examination Survey (1999-2002). The hazard ratios ranged from 1.25 (95% confidence interval: 1.13, 1.37) per 10-mm Hg increase in systolic blood pressure among men aged 收起
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The electronic g-tensor calculations are performed for dangling bonds (DBs) introduced into nanodiamonds (NDs) with four different functional groups on their surfaces. For hydrogenated and fluorinated NDs, it is found that g-shift...
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The electronic g-tensor calculations are performed for dangling bonds (DBs) introduced into nanodiamonds (NDs) with four different functional groups on their surfaces. For hydrogenated and fluorinated NDs, it is found that g-shifts of the latter vary in a much wider range, and the same is also true for the total energy differences between the highest and the lowest energy DBs. In addition, it is shown that the shape of NDs significantly impacts the energetics and g-shifts of DBs, whereas the influence of the size is much less pronounced, as is the influence of the presence of one DB in the vicinity of the other, resulting in no substantial change on their magnetic behavior. For hydroxylated and aminated NDs, it is demonstrated that the variation range of g-shifts is larger for the former, whereas the opposite is seen regarding the total energy differences. On the whole, some of the positions of DBs can be energetically very costly in these NDs; besides, the lowest energy DBs are irregular, that is, formed by OH- and NH2-bonded C atoms, contrasting with hydrogenated and fluorinated NDs, for which irregular DBs are the most energetically unfavorable.
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A new method based on the surface tension measurement for fast evaluating modification effect of Al-Si alloy in front of furnace and an automatic system for fast measuring surface tension of molten Al-Si alloy are introduced. By t...
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A new method based on the surface tension measurement for fast evaluating modification effect of Al-Si alloy in front of furnace and an automatic system for fast measuring surface tension of molten Al-Si alloy are introduced. By theoretical analysis the relation between surface tension sigma_e of molten Al-Si alloy and information parameters DELTA P, N, psi_x and Thas been established, namely, sigma_e = a centre dot DELTA P + b centre dot N+c centre dot (psi_x-psi_o) + d centre dot T+e. By ex- periments the relationship between surface tension and modification level of Al-Si alloy has been also got that sigma_e > 530 mN/m, 400 收起
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Although many researchers have estimated crash modification factors (CMFs) for specific treatments (or countermeasures), there is a lack of studies that explored the heterogeneous effects of roadway characteristics on crash freque...
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Although many researchers have estimated crash modification factors (CMFs) for specific treatments (or countermeasures), there is a lack of studies that explored the heterogeneous effects of roadway characteristics on crash frequency among treated sites. Generally, the CMF estimated by before-after studies represents overall safety effects of the treatment in a fixed value. However, as each treated site has different roadway characteristics, there is a need to assess the variation of CMFs among the treated sites with different roadway characteristics through crash modification functions (CMFunctions). The main objective of this research is to determine relationships between the safety effects of adding a bike lane and the roadway characteristics through (1) evaluation of CMFs for adding a bike lane using observational before-after with empirical Bayes (EB) and cross-sectional methods, and (2) development of simple and full CMFunctions which are describe the CMF in a function of roadway characteristics of the sites. Data was collected for urban arterials in Florida, and the Florida-specific full SPFs were developed. Moreover, socio-economic parameters were collected and included in CMFunctions and SPFs (1) to capture the effects of the variables that represent volume of bicyclists and (2) to identify general relationship between the CMFs and these characteristics. In order to achieve better performance of CMFunctions, data mining techniques were used. The results of both before-after and cross-sectional methods show that adding a bike lane on urban arterials has positive safety effects (i.e., CMF ＜ 1) for all crashes and bike crashes. It was found that adding a bike lane is more effective in reducing bike crashes than all crashes. It was also found that the CMFs vary across the sites with different roadway characteristics. In particular, annual average daily traffic (AADT), number of lanes, AADT per lane, median width, bike lane width, and lane width are significant characteristics that affect the variation in safety effects of adding a bike lane. Some socio-economic characteristics such as bike commuter rate and population density also have significant effect on the variation in CMFs. The findings suggest that full CMFunctions showed better model fit than simple CMFuncttions since they account for the heterogeneous effects of multiple roadway and socio-economic characteristics. The proposed CMFunctions provide insights into bike lane design and selection of sites for bike lane installation for reducing crashes.
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As a novel rich nitrogen content material, 5-Amino-1H-Tetrazole (5AT) has been considerably popularized in the propellants area recently. The pyrolysis is deemed as the prelude of combustion for solid phase 5AT, which plays a cruc...
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As a novel rich nitrogen content material, 5-Amino-1H-Tetrazole (5AT) has been considerably popularized in the propellants area recently. The pyrolysis is deemed as the prelude of combustion for solid phase 5AT, which plays a crucial role in combustion process and grasping the pyrolysis characteristics will be more beneficial to further explore the combustion properties of 5AT-based propellant. In this paper, several efforts have been made to enhance the pyrolysis behaviors of 5AT, including employing metal particles as catalysts, and modifying the surface treatment method. Due to the calorific value, the boron and copper powder are selected as the potential catalysts. The solvent/non-solvent (S/NS) and solution recrystallization method are compared to explore the impact of these two modification methods. TG-FTIR technique is applied to capture evolved signals of organic compounds to further deduce the most probable decomposition pathway. Moreover, model-free and model-fitting methods are both employed to calculate the kinetic parameters. The results reveal that, for the modified 5AT samples with the same boron powder catalyst, the activation energies and reaction model (all governed by F4) in the initial stage (100-330 degrees C) are not significantly impacted by these two modification methods. However, during the latter stages (400-750 degrees C), the catalytic actions of boron powder appear to be more active, and solution recrystallization method exerts better modification effect, the activation energies was reduced 18.3 kJ/mol and 10.9 kJ/mol respectively for the latter stages compared to S/SN method. Also, the reaction model is transformed from n(th-)dimensional model (D3) to n(th)-order model (F1) in the third stage. Particularly, the catalytic actions of copper powder results in the simplification of decomposition steps for 5AT, the activation energies was 138.8 kJ/mol and the catalytic effect of which was improved about 25% compared to the catalytic effect of boron powder in the first stage and its reaction model is also found to be changed into F3. It illustrates that copper powder could embody a better catalytic effect than boron powder under the same modification method. The conclusions of this study could provide a worthwhile guidance for the understanding, designs and applications of the 5AT-based propellants.
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The application of nanoparticles for latent fingermark detection has been reported in the literature over the past two decades. One of the nanoparticles that shows promise to become a routine technique is functionalised silicon ox...
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The application of nanoparticles for latent fingermark detection has been reported in the literature over the past two decades. One of the nanoparticles that shows promise to become a routine technique is functionalised silicon oxide nanoparticles (SiO2 NPs). In a recent optimisation of the technique, the use of carboxyl-functionalised SiO2 NPs doped with luminescent ruthenium complex was proposed as a breakthrough for latent fingermark detection.
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While most studies assess the cost-effectiveness of treating acute coronary conditions, the Century Health Study for Cardiovascular Medicine (Century Trial) focuses on ameliorating coronary artery disease (CAD) through a comprehen...
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While most studies assess the cost-effectiveness of treating acute coronary conditions, the Century Health Study for Cardiovascular Medicine (Century Trial) focuses on ameliorating coronary artery disease (CAD) through a comprehensive lifestyle modification program. This 1,300- patient phase III randomized study uses positron emission tomography for risk stratification, complemented with comprehensive educational and motivational therapy for patients with preclinical or established CAD. The Century Trial is in its second year of a five-year follow-up protocol, and it is one of the first to combine imaging technology and lifestyle modification as a way to improve patient behavior and health. In this article, we present the economic study design used in the Century Trial and provide considerable methodological detail to serve as reference for other researchers.We describe the cost and effect estimation methods as well as our analysis and uncertainty modeling plans. The study will incorporate quality-adjusted life years and use a societal perspective to measure both in-trial and lifetime costs through incremental cost-effectiveness ratios. The approach we follow should provide further evidence on the costeffectiveness of comprehensive lifestyle modification programs in regressing coronary artery disease.
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