Search results

It is an indispensable part of airworthiness certification to evaluate the fuel tank flammability exposure time for transport aircraft. There are many factors and complex coupling relationships affecting the fuel tank flammability exposure time. The current work not only lacks a comprehensive analysis of these factors but also lacks the significance of each factor, the interaction relationship and the prediction method of flammability exposure time. The lack of research in these aspects seriously restricts the smooth development of the airworthiness forensics work of domestic large aircraft. This paper aims to clarify the internal relationship between user input parameters and predict the flammability exposure time of fuel tanks for transport aircraft.

Based on the requirements of airworthiness certification for large aircraft, an in-depth analysis of the Monte Carlo flammability evaluation source procedures specified in China Civil Aviation Regulation/FAR25 airworthiness regulations was made, the internal relationship between factors affecting the fuel tank flammability exposure time was clarified and the significant effects and interactions of input parameters in the Monte Carlo evaluation model were studied using the response surface method. And the BP artificial neural network training samples with high significance factors were used to establish the prediction model of flammability exposure time.

The input parameters in the Monte Carlo program directly or indirectly affect the fuel tank flammability exposure time by means of the influence on the flammability limit or fuel temperature. Among the factors affecting flammability exposure time, the cruising Mach number, balance temperature difference and maximum range are the most significant, and they are all positively correlated with flammability exposure time. Although there are interactions among all factors, the degree of influence on flammability exposure time is not the same. The interaction between maximum range and equilibrium temperature difference is more significant than other factors. The prediction model of flammability exposure time based on multifactor interaction and BP neural network has good accuracy and can be applied to the prediction of fuel tank flammability exposure time.

The flammability exposure time prediction model was established based on multifactor interaction and BP neural network. The limited test results were combined with intelligent algorithm to achieve rapid prediction, which saved the test cost and time.

Exploiting novel measures of climate change exposure and corporate culture generated by a powerful textual analysis of earnings conference calls, this study aims to explore the effect of firm-specific climate change exposure on corporate innovation through the lens of corporate culture.

The authors apply the standard regression analysis as well as a variety of sophisticated techniques, namely, propensity score matching, entropy balancing and an instrumental-variable analysis with multiple alternative instruments.

The authors find that more exposure to climate change risk results in more innovation, as indicated by a significantly stronger culture of innovation. The findings are consistent with the notion that firms more exposed to climate change risk are pressed to be more innovative to adapt to the numerous changes caused by climate change. Finally, the authors also find that the effect of firm-level exposure on innovation is considerably less pronounced during uncertain times.

The authors are among the first studies to take advantage of a novel measure of firm-specific exposure to climate change and investigate how climate change exposure influences an innovative culture. Since climate change is a timely issue, the findings offer important implication to several stakeholders, such as shareholders, executives and investors in general.

Misperceptions hinder our ability to effectively respond to health crises such as the COVID-19. We aimed to examine the dynamic influences between information exposure, information trust and misperceptions during the early phase of the COVID-19 pandemic. Specifically, we focused on the relative influence of exposure to COVID-19-related information via social media versus interpersonal offline communication.

The current study conducted a two-wave national survey of US adults in May and June of 2020 with a two-week time interval. A professional polling firm recruited participants, and 911 and 679 respondents participated in the first and the second wave survey, respectively. To test proposed hypotheses, researchers conducted path analyses using AMOS 27.0.

Findings show that individuals exposed to COVID-19-related information via social media are likely to hold increased misperceptions. In contrast, exposure to COVID-19-related information offline did not elicit any effects on misperceptions. The exposure to information on social media was positively associated with trust in that information, which, in turn, contributed to an increase in misperceptions. Furthermore, when examining the effects of misperception, it was found that misperceptions increased the likelihood of individuals being exposed to and having trust in COVID-19-related information on social media. The findings provide valuable insights into the role of social media as a platform where a detrimental cycle thrives, shaping the formation of misperceptions and cultivating a heightened dependence among individuals with elevated misperceptions.

The current study significantly extends the findings of prior research by examining the differential effects of social media and interpersonal communication offline on misperception and by revealing the intricate dynamics between information exposure and misperception by focusing on the role of trust. The findings emphasize the detrimental role of social media in generating a vicious information cycle. That said, seemingly superficial discussions about health crises within a social media environment rich in misinformation can contribute to fueling a self-reinforcing loop, making it challenging to effectively counteract misperceptions.

The purpose of this paper is to estimate the influence of long‐term, whole‐body exposure of rats to strong, static electric field with physical parameters generated nearby high voltage direct current (HVDC) transmission lines on the intensity of reactive oxygen species generation analyzed indirectly, basing on the measurement of malone dialdehyde level, as well as on the activity of enzymatic antioxidant defence system.

In rats exposed to static electric field with intensity of 16, 25 and 35 kV/m, respectively, or sham‐exposed eight hours daily for 56 days, in the obtained plasma, erythrocytes lysates and liver homogenates the activity of some antioxidant enzymes as well as the concentration of malone dialdehyde were determined with use of spectrophotometric and kinetic methods.

It was observed that long‐term exposure of rats to static electric field causes only temporary compensatory changes in the concentration of malone dialdehyde and transient changes in the activity of enzymatic antioxidant system, both in blood and in liver tissue in the form of temporary inhibition of activity of most antioxidant enzymes during exposure cycle, with subsequent compensatory increase in this activity after the end of exposure cycle, enabling maintenance of prooxidant‐antioxidant balance in the organism of experimental animals and inhibition of peroxidation process.

Presented data indicate that construction of air HVDC transmission lines, according to actual compulsory regulations, enables serious health hazards related to persistent disturbances of prooxidant‐antioxidant balance to be avoided.

In the experiment it was confirmed, for the first time, that long‐term exposure to strong static electric field causes transient compensatory changes of prooxidant‐antioxidant balance in living organisms.

The purpose of this paper is to review the impact of a new, brief forensic rotation for general psychiatry residents on the variety of residents’ forensic exposures.

The authors surveyed residents who trained before and after the implementation of the new rotation to assess the impact of the rotation on the residents’ forensic experiences during training across a variety of domains.

Even in a highly clinical forensic setting, residents participating in the required rotation reported significantly greater variety of forensic experiences than those who had not completed the required rotation, including types of settings and assessments, Rotation completers reported greater exposure to various types of settings and assessments, and courtroom-related experiences, as well as the overall number of forensic exposures. The two groups did not differ in their forensic exposures in general psychiatry settings, civil-forensic evaluations or diverse forensic populations. Secondary analyses showed that increased exposure to court-based experiences and multiple forensic settings was associated with forensic fellowship interest.

This study demonstrates that a brief, mandatory forensic clinical rotation may increase residents’ exposure to forensic settings, assessments and courtroom-related experiences and that increased exposure to courtroom-based experiences in particular may increase interest in forensic fellowship. While not surprising, the results demonstrate that residents were not otherwise having these forensic experiences and that even time-limited forensic rotations can enhance the breadth of residents’ forensic exposures. Further, the rotation achieved these outcomes without using typical forensic sites but instead highly clinical sites, which may be particularly encouraging to residency programs without ready access to classic forensic rotation sites. This study contributes to the small but expanding body of the literature describing the value of increasing psychiatry residents’ training in clinical forensic psychiatry.

This paper presents the results from 149 responses to an August 1992 mail questionnaire survey of CEOs of the Business Week 1000 firms to examine their perception of liability exposure and reaction to it within the agency framework. The results suggest that liability exposure has resulted in a variety of actions to reduce exposure to potential liability from lawsuits. The actions should result in better monitoring by directors and officers with no significant increase in monitoring costs but instead, a significant decrease in the residual loss. The net effect should be a decrease in agency costs, consistent with maximization of shareholder wealth.

The occupational health risk associated with the production of prefabricated concrete components is often overlooked. This paper will use a damage assessment and cyclic mitigation (DACM) model to provide individualized exposure risk assessment and corresponding mitigation management measures for workers who are being exposed.

The DACM model is proposed based on the concept of life cycle assessment (LCA). The model uses Monte-Carlo simulation for uncertainty risk assessment, followed by quantitative damage assessment using disability-adjusted life year (DALY). Lastly, sensitivity analysis is used to identify the parameters with the greatest impact on health risks.

The results show that the dust concentration is centered around the mean, and the fitting results are close to normal distribution, so the mean value can be used to carry out the calculation of risk. However, calculations using the DACM model revealed that there are still some work areas at risk. DALY damage is most severe in concrete production area. Meanwhile, the inhalation rate (IR), exposure duration (ED), exposure frequency (EF) and average exposure time (AT) showed greater impacts based on the sensitivity analysis.

Based on the comparison, the DACM model can determine that the potential occupational health risk of prefabricated concrete component (PC) factory and the risk is less than that of on-site construction. It synthesizes field research and simulation to form the entire assessment process into a case-base system with the depth of the cycle, which allows the model to be continuously adjusted to reduce the occupational health damage caused by production pollution exposure.

Taking advantage of distinctive text-based measures of climate policy uncertainty and firm-specific exposure to climate change, this study aims to examine the impact of firm-specific vulnerability on dividend policy.

To mitigate endogeneity, the authors apply an instrumental-variable analysis based on climate policy uncertainty as well as use additional analysis using propensity score matching and entropy balancing.

The authors show that an increase in climate policy uncertainty exacerbates firm-specific exposure considerably. Exploiting climate policy uncertainty to generate exogenous variation in firm-specific exposure, the authors demonstrate that companies more susceptible to climate change are significantly less likely to pay dividends and those that do pay dividends pay significantly smaller dividends. For instance, a rise in firm-specific exposure by one standard deviation weakens the propensity to pay dividends by 5.11%. Climate policy uncertainty originates at the national level, beyond the control of individual firms and is thus plausibly exogenous, making endogeneity less likely.

To the best of the authors’ knowledge, this study is the first attempt in the literature to investigate the effect of firm-specific exposure on dividend policy using a rigorous empirical framework that is less vulnerable to endogeneity and is more likely to show a causal influence, rather than a mere correlation.

This study proposes targeted modernization of the Department of Defense (DoD's) Joint Forces Ammunition Logistics information system by implementing the optimized innovative information technology open architecture design and integrating Radio Frequency Identification Device data technologies and real-time optimization and control mechanisms as the critical technology components of the solution. The innovative information technology, which pursues the focused logistics, will be deployed in 36 months at the estimated cost of $568 million in constant dollars. We estimate that the Systems, Applications, Products (SAP)-based enterprise integration solution that the Army currently pursues will cost another $1.5 billion through the year 2014; however, it is unlikely to deliver the intended technical capabilities.

To study the determinants and effects of “Operational” exchange rate exposure resulting from the mismatch between cost and revenues of the firms by using data on 500 Indian firms.

We conduct detailed empirical analysis of the determinants of firm level exposure and their impact using panel regression techniques and conduct several robustness tests to confirm the validity of these results.

Among other factors, exchange rate volatility appears as a significant determinant of average firm level exposure with the direction of relationship supporting the presence of “Moral Hazard” in firm’s risk-taking behavior. Further large “operational” exposure is associated with significantly lower output growth, profitability, and capital expenditure during episodes of large currency depreciation at the firm level.

This paper leaves several questions to be answered. Further research is called for to explore the nature of distortions in the production process encouraged by exchange rate volatility and their impact on firm level productivity. Looking at the relationship between the use of financial and operational hedges is another fruitful area of future research.

Our results have important implications for policy makers worried about mitigating the impact of exogenous shocks. Implicit and explicit guarantees with regards to the value of exchange rate tend to raise the vulnerability of the economy to exchange rate shocks at same time that they encourage capital expenditures and possibly output growth during “normal” times. Our findings indicate that the policy makers must take into account the incentive effects of their intervention in foreign exchange markets.

Unlike the existing papers in the literature, we use a measure of “operational” currency exposure based on foreign currency revenues and costs of firms. In most of the existing papers the focus is on the mismatch between the currency denomination of assets and liabilities. Little attention has been paid to the currency mismatch between costs and revenues of the firms. Such “operational” mismatches are potentially equally important and deserve attention of policy makers and academics alike.