Crack Resistance of Prestressed Reinforced Concrete Beams with Wire Rope Reinforcement.

One of the main objectives of capital construction worldwide is to increase the efficiency of construction. To achieve this, a significant improvement in the quality of concrete and reinforced concrete is required. Nowadays, in developed countries, one of the key directions for enhancing the efficiency of concrete and reinforced concrete is reducing their density by using inexpensive and high-quality local porous fillers. In recent years, the use of concrete structures with porous fillers based on ceramporite in load-bearing reinforced concrete structures has allowed for the improvement of their technical and economic indicators and the reduction in their own weight by up to 35%. This, in turn, is considered an essential factor in seismic zones, and therefore, special attention is paid to these issues. This article presents the data of experimental and theoretical studies obtained from investigating the crack resistance of prestressed lightweight reinforced concrete flexural elements with wire rope reinforcement. The main factors influencing crack resistance were considered, including the effects of two types of porous filler (ceramporite), two types of concrete, concrete strength, percentage of reinforcement, and level of precompression. The tests were conducted using short-term and repeated loadings. Based on the analysis of the obtained data, some refinements have been made to the methodology for calculating the crack resistance of such structures according to current design standards.

Gender differences in perceived legitimacy and status perception in leadership role.

The present study examined the difference between women and men in perceiving leadership roles. Two experiments, one conducted online and the other in a lab, investigated the subjective experiences of Japanese men and women when they are assigned with different roles (e.g., leader vs. subordinate). Both studies revealed that women perceived their role as less legitimate when they were assigned leader role (vs. subordinate role). In contrast, men did not differ in their perceived legitimacy according to the assigned roles. This discrepancy in legitimacy perception in response to different roles between men and women accounted for a significant variance in women's lower sense of status when they were a leader (vs. subordinate), but not among men. Our study results illustrate the psychological barrier operating for women in organizations that are embedded in a cultural context in which women leaders are highly underrepresented.

Active SMA Fibers' Effect on the Pullout Behavior of a Steel Bar Embedded in Concrete.

This study investigated the bond behavior and radial crack between concrete and reinforcing bars using cold-drawn shape memory alloy (SMA) crimped fibers controlled by the temperature and volume fraction of the fibers. In this novel approach, the concrete specimens containing cold-drawn SMA crimped fibers with 1.0% and 1.5% volume fractions of cold-drawn SMA fibers were prepared. After that, the specimens were heated to 150 °C to generate recovery stress and activate prestressing within the concrete. The bond strength of specimens was estimated by pullout test using the universal testing machine (UTM). Furthermore, the cracking patterns were investigated using radial strain measured by a circumferential extensometer. The results showed that adding up to 1.5% of SMA fibers improved the bond strength by 47.9% and reduced radial strain by more than 54%. Thus, heating specimens containing SMA fibers showed improved bond behavior compared with non-heated specimens with the same volume fraction.

Older people are not always happier than younger people: The moderating role of personality.

The present research explored whether the well-established U-shaped relationship between age and happiness varied with personality. Individuals ranging from 15 to 75 years of age (N = 10,456, 84.9% female) completed online surveys of subjective well-being (i.e. life satisfaction, positive affect, and negative affect) and the Big Five personality traits (International Personality Item Pool [IPIP]). The results of hierarchical multiple regression using the PROCESS macro not only supported the prediction of a U-shaped relationship between age and well-being but also revealed that the quadratic relationship is moderated by agreeableness and neuroticism. Specifically, well-being did not bounce back in later adulthood on the well-being curve across different age groups with low agreeableness and high neuroticism. Moreover, positive affect did not increase and even decreased in later adulthood among those with low agreeableness. This study discusses the potential mechanisms.

Finite Bending of Fiber-Reinforced Visco-Hyperelastic Material: Analytical Approach and FEM.

This paper presents a new anisotropic visco-hyperelastic constitutive model for finite bending of an incompressible rectangular elastomeric material. The proposed approach is based on the Mooney-Rivlin anisotropic strain energy function and non-linear visco-hyperelastic method. In this study, we aim to examine the mechanical response of a reinforced viscoelastic rectangular bar with a group of fibers under bending. Anisotropic materials are typically composed of one (or more) family of reinforcing fibers embedded within a soft matrix material. This operation may lead to an enhancement in the strength and stiffness of soft materials. In addition, a finite element simulation is carried out to validate the accuracy of the analytical solution. In this research, the well-known stress relaxation test, as well as the multi-step relaxation test, are examined both analytically and numerically. The results obtained from the analytical solution are found to be in good agreement with those from the finite element method. Therefore, it can be deduced that the proposed model is competent in describing the mechanical behavior of fiber-reinforced materials when subjected to finite bending deformations.

Optimal Implementation Parameters of a Nonlinear Electrical Impedance Tomography Method Using the Complete Electrode Model.

This study discusses a nonlinear electrical impedance tomography (EIT) technique under different analysis conditions to propose its optimal implementation parameters. The forward problem for calculating electric potential is defined by the complete electrode model. The inverse problem for reconstructing the target electrical conductivity profile is presented based on a partial-differential-equation-constrained optimization approach. The electrical conductivity profile is iteratively updated by solving the Karush-Kuhn-Tucker optimality conditions and using the conjugate gradient method with an inexact line search. Various analysis conditions such as regularization scheme, number of electrodes, current input patterns, and electrode arrangement were set differently, and the corresponding results were compared. It was found from this study that the proposed EIT method yielded appropriate inversion results with various parameter settings, and the optimal implementation parameters of the EIT method are presented. This study is expected to expand the utility and applicability of EIT for the non-destructive evaluation of structures.

Gender discrimination in workplace and depressive symptoms in female employees in South Korea.

BACKGROUND: Workplace gender discrimination (WGD) may have long-term negative impacts on female workers' mental health. We aimed to investigate the association between WGD and the prevalence of depressive symptoms using a nationally representative sample of female employees in South Korea. METHODS: Data of 3190 adult female employees were obtained from the 2018 nationwide Korean Longitudinal Survey of Women and Families. Women's perception of WGD was assessed using a 6-item questionnaire. Respondents were classified into high, medium, and low levels of WGD according to the 25th and 75th percentile scores. A score of ≥10 on the 10-item version of the Center for Epidemiologic Studies for Depression Scale was defined as having significant depressive symptoms. RESULTS: A high level of WGD was significantly associated with a higher odds ratio (OR) for depressive symptoms compared to the low level (OR = 1.87, 95% confidence interval = 1.45-2.41). In the subgroup analyses, high WGD levels were associated with the highest OR for depressive symptoms in the following subgroups: younger age (19-39 years), those with a college degree, non-standard workers, pink collar workers, those with a workplace size of 10-29 employees, those with high levels of job autonomy, or low levels of emotional labor. LIMITATIONS: Causal interpretation is limited owing to the study's cross-sectional design. CONCLUSIONS: A high level of perceived WGD was associated with depressive symptoms among female employees. Certain groups of female employees may be particularly vulnerable to the detrimental effects of WGD on depression.

Continuous VOCs Monitoring in Saturated and Unsaturated Zones Using Thermal Desorber and Gas Chromatography: System Development and Field Application.

Subsurface VOC monitoring has been mainly based on manual sampling, transport, and analysis, which would require a sufficient amount of samples to ensure data accuracy and reliability, and additional costs to ensure sample quality. Therefore, a continuous on-site monitoring system is desirable for accurate measurement and subsequent risk assessment. In this study, benzene, toluene, ethylbenzene, and xylene (BTEX) were continuously monitored by the system based on a thermal desorber (TD) and gas chromatography (GC) in an oil-contaminated site that consisted of saturated and unsaturated zones. For the saturated zone, fully automated groundwater sampling and purging processes were performed, and the gasified samples were applied to the TD-GC system. For the unsaturated zone, the gaseous sample in the site was directly applied to the TD-GC system. After verifying the accuracy and precision of the monitoring system, the continuous monitoring system was successfully operated for more than a month in the field. The monitoring system used in this study is applicable to other sites for continuous monitoring, thus providing a scientific background for advanced risk assessment and policy development.

Impact of face masks and sunglasses on emotion recognition in South Koreans.

Due to the prolonged COVID-19 pandemic, wearing masks has become essential for social interaction, disturbing emotion recognition in daily life. In the present study, a total of 39 Korean participants (female = 20, mean age = 24.2 years) inferred seven emotions (happiness, surprise, fear, sadness, disgust, anger, surprise, and neutral) from uncovered, mask-covered, sunglasses-covered faces. The recognition rates were the lowest under mask conditions, followed by the sunglasses and uncovered conditions. In identifying emotions, different emotion types were associated with different areas of the face. Specifically, the mouth was the most critical area for happiness, surprise, sadness, disgust, and anger recognition, but fear was most recognized from the eyes. By simultaneously comparing faces with different parts covered, we were able to more accurately examine the impact of different facial areas on emotion recognition. We discuss the potential cultural differences and the ways in which individuals can cope with communication in which facial expressions are paramount.

Validation of the Korean version of the obsession with COVID-19 scale and the Coronavirus anxiety scale.

In response to the current COVID-19 pandemic, the Obsession with COVID-19 scale (OCS) and the Coronavirus Anxiety Scale (CAS) were developed as screening tools for dysfunctional anxiety associated with the coronavirus. These scales have not yet been validated in the East Asia. The present study examined the validity of the OCS and the CAS with a sample of 329 Korean adults. We found that the OCS-Korean and CAS-Korean showed good psychometric properties and construct validity. Developing such valid screening tools across different cultures is vital for health practitioners and scholars alike during global infectious disease outbreaks.

To drink, or to exercise: That is (not) the question! Daily effects of alcohol consumption and exercise on well-being.

Drinking alcohol and exercising are two of the most popular ways of dealing with stress. Despite the fact that they often co-occur, few studies have examined the role of the two activities together in everyday well-being. The current research aimed to investigate the dynamics between these two daily activities and various indices of well-being in a natural environment by using a daily diary method and ecological momentary assessment. We asked 478 adults to record their alcohol intake, exercising activity, and momentary well-being, three times a day for 2 weeks. Significant detrimental effects of drinking alcohol and beneficial effects of exercising on well-being were observed on the next day, whereas no significant effect of well-being was found on the likelihood of drinking and exercising on the second day. Furthermore, sleep quality was identified as one of the factors influencing the changes of well-being induced by the drinking and exercising engaged in the previous day. The present research allows us to deepen our understanding of the lagged relationship between the daily activities of drinking alcohol/exercising and well-being and demonstrates the underlying mechanism for the observed effects. Theoretical and practical implications are discussed.

Effect of Tension-Compression Asymmetry Response on the Bending of Prismatic Martensitic SMA Beams: Analytical and Experimental Study.

This paper aims to analytically derive bending equations, as well as semi-analytically predict the deflection of prismatic SMA beams in the martensite phase. To this end, we are required to employ a simplified one-dimensional parametric model considering asymmetric response in tension and compression for martensitic beams. The model takes into account the different material parameters in martensite twined and detwinned phases as well as elastic modulus depending on the progress of the detwinning process. In addition, the model considers the diverse slope of loading and unloading in martensite detwinned phases favored by tension and compression. To acquire general bending equations, we first solve the pure bending problem of a prismatic SMA beam. Three different phases are assumed in the unloading procedure and the effect of neutral fiber distance from the centerline is also considered during this stage. Then according to the pure bending solution and employing semi-analytical methods, general bending equations of an SMA beam are derived. Polynomial approximation functions are utilized to obtain the beam deflection-length relationship. To validate the attained analytical expressions, several three- and four-point bending tests were conducted for rectangular and circular SMA beams. Experimental data confirm the reasonable accuracy of the analytical results. This work may be envisaged to go deep enough in investigating the response of SMA beams under an arbitrary transverse loading and stress distribution during loading and unloading, as well as findings may be applicable to a good prediction of bending behavior.

Straining Behavior of Mortar Reinforced by Cold Drawn Crimped and Dog-Bone-Shaped Fibers under Monotonic and Cyclic Compressions.

The straining behavior of the shape memory alloy (SMA) fibers-reinforced mortar was investigated in this study by the monotonic compressive and cyclic compressive tests. Two types of SMA fibers with a crimped and dog-bone shape were used due to the high pullout resistance capacity, which guaranteed that the fibers and mortar matrix were composited well. The plain mortar was mixed with two different compositions to create the higher elastic modulus mortar matrix and the lower elastic modulus mortar matrix compared with the elastic modulus of SMA fibers. The results of the experimental test indicated that the non-heated SMA fibers could control the strains in both elastic and plastic phases; in which, the crimped fiber was more effective in precracking due to the higher composite capacity while the dog-bone-shaped fiber had a higher effect in post-cracking. After heating, the dog-bone-shaped fiber slipped more than that of the crimped fiber; thus, the heated crimped fiber was more effective than the heated dog-bone-shaped fiber in controlling strains after cracking. The effect of SMA fibers on the elastic modulus depended on both the elastic modulus of mortar matrix and the property of SMA fibers. In the plastic phase, the fibers were effective on reducing the speed of damage in monotonic case. An equation using reinforcing index was suggested for damage evolution in the cyclic case.

How COVID-19 affected mental well-being: An 11- week trajectories of daily well-being of Koreans amidst COVID-19 by age, gender and region.

The present study examined the daily well-being of Koreans (n = 353,340) for 11 weeks during the COVID-19 pandemic (January 20 -April 7). We analyzed whether and how life satisfaction, positive affect, negative affect, and life meaning changed during the outbreak. First, we found that the well-being of Koreans changed daily in a cubic fashion, such that it declined and recovered during the early phase but declined substantially during the later phase (after COVID- 19 was declared world pandemic by WHO). Second, unlike other emotions, boredom displayed a distinctive pattern of linear increase, especially for younger people, suggesting that boredom might be, in part, responsible for their inability to comply with social distancing recommendations. Third, the well-being of older people and males changed less compared to younger people and females. Finally, daily well-being dropped significantly more in the hard-hit regions than in other regions. Implications and limitations are discussed.

Long working hours and depressive symptoms: moderation by gender, income, and job status.

BACKGROUND: Long working hours can be a risk factor for poor mental health; however, little is known about the potential factors moderating their relation. This study investigates the association between working hours and depressive symptoms, and explores the potential moderating effect of gender, income level, and job status on this association using a nationally representative sample of working population in South Korea. METHODS: Data of 7,082 workers aged 19 years or above were obtained from the Korea National Health and Nutrition Examination Surveys (KNHANES) conducted in 2014, 2016, and 2018 in South Korea. Working hours were categorized into 35-39, 40, 41-52, 53-68, and ≥69 hours/week. Depressive symptoms were evaluated using the Patient Health Questionnaire-9 (PHQ-9). RESULTS: Individuals working ≥69 hours/week were more likely to have moderate to severe depressive symptoms compared to those working 40 hours/week. The association between longer working hours and depressive symptoms was especially prominent in female workers, standard wage workers, and workers with low income levels. We observed significant partial mediation pathways between working hours and PHQ-9 scores through both perceived usual stress level and self-rated health in the total sample. LIMITATIONS: The cross-sectional design of the study limits causal interpretation of the findings. CONCLUSION: Working longer than the legal upper limit of 52 hours/week puts workers at a greater risk for depression. Females, low-income workers, and wage workers are more vulnerable to the negative consequences of long working hours on mental health.

Essentializing happiness reduces one's motivation to be happier.

OBJECTIVE: The present study examined the essentialist lay theories of happiness (i.e., beliefs that happiness is determined by one's genes and hence, immutable) and its implications for motivation to enhance one's happiness level. METHOD: Study 1 (N = 454) developed a scale called the "Essentialist Beliefs about Happiness (EBH)" and Study 2 (N = 207) validated the scale by comprehensively examining conceptually overlapping constructs related to the EBH. In Study 3 (N = 401) and Study 4 (N = 452), by utilizing correlational and experimental methods, we tested the effect of the EBH on motivation to enhance happiness. RESULTS: Using the scale developed and validated in Study 1 and Study 2, Study 3 and Study 4 found that the essentialist beliefs about happiness predicted reduced motivation to be happier. Specifically, participants with greater essentialist beliefs about happiness were less likely to engage in happiness-boosting activities. Specifically, those who believed that happiness is influenced by one's attitude and effort had greater intention to engage in happiness-boosting activities. CONCLUSIONS: The present results provide new insight into the role of individual differences in essentialist lay theories of happiness in motivational state in well-being domain.

Individualism-collectivism during the COVID-19 pandemic: A field study testing the pathogen stress hypothesis of individualism-collectivism in Korea.

The pathogen stress hypothesis posits that pathogen-related threats influence regional and individual differences in collectivism since behavioral practices associated with collectivism limit the spread of infectious diseases. In support of the hypothesis, previous research demonstrates the association between individualism/collectivism and pathogen stress based on historical records or experimental manipulation. However, it is still unclear whether individuals would indeed value collectivism during the outbreak of infectious diseases. Thus, we investigated the concurrent effects of pathogen-related stress on the endorsement of individualism/collectivism by examining 9322 Koreans for 14 weeks of the COVID-19 pandemic. The results revealed that the level of collectivism among respondents were higher after than before the COVID-19 outbreak. Moreover, the average level of collectivism on a given day showed a significant association with the number of confirmed COVID-19 cases on the same day during the outbreak. Interestingly, individualism did not significantly change for the same period.

Within-person day-of-week effects on affective and evaluative/cognitive well-being among Koreans.

Day-of-week (DOW) effects such as "blue Monday," "Thank God it's Friday" (TGIF), and weekend effects have mostly been investigated using a cross-sectional approach with Western samples and focusing on hedonic aspects of well-being. Using large-scale data (N = 859,749) containing multiple observations per person collected from Koreans, we examined various patterns of DOW effects on comprehensive measures of well-being. Unlike previous studies, we examined DOW effects at the within-person level. Blue Monday and TGIF effects were evident across affective and evaluative/cognitive aspects of well-being, and the Thursday nadir phenomenon was also found. The DOW effects were consistent for the affective well-being, whereas no weekend effects were observed for the cognitive aspects, including life satisfaction and meaning in life. The DOW effects were moderated by gender and age groups, with younger people tending to experience more salient DOW effects and women identifying fewer benefits from DOW effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Social participation and depressive symptoms in community-dwelling older adults: Emotional social support as a mediator.

Previous studies have documented the protective effects of social participation on depression in older adults. In this study, we investigated the association between social participation and depressive symptoms and the associated gender difference in older adults. In addition, we explored the mediating role of emotional social support in the association between social participation and depressive symptoms. We collected data from 4751 community-dwelling adults aged 60 and above from the Korean Retirement and Income Study (KReIS) conducted in 2017 and 2018. The relationship between social participation (participation in different types of activities, frequency of participation, and the number of activities participated) and the risk for depressive symptoms was examined. Older adults who participated in social activity, volunteer work, and donation had decreased risk of depressive symptoms. More frequent and more diverse participation in activities further reduced the risk. Overall, women benefited more from social participation than men. Importantly, emotional social support significantly mediated the relationship between social participation and depressive symptoms. Social participation was associated lower odds for depression in older adults, particularly in older women. Our findings provided one of very few pieces of evidence that documents the mediating role of emotional social support in the relationship between social participation and depression among the elderly.

Active Reinforcing Fiber of Cementitious Materials Using Crimped NiTi SMA Fiber for Crack-Bridging and Pullout Resistance.

This study investigated the recovery stress and bond resistance of cold drawn crimped SMA fiber using two different initial diameters of 1.0 and 0.7 mm. These characteristics are important to the active prestressing effect and crack-closing of the fiber. NiTi SMA fiber was used for the cold drawing, and then crimped shapes were manufactured with various wave heights. After that, tensile, recovery, and pullout tests were conducted. The cold drawn crimped fiber showed softening tensile behavior more clearly than the cold drawn straight fiber when not subjected to heating, whereas they had the same tensile behavior under heating. The recovery stress and the residual stress of the crimped fibers were less than those of the straight fiber with the same diameter. Moreover, crimped fibers with a large diameter and higher wave height would induce more recovery stress and residual stress. The maximum pullout resistance of the crimped fiber was a function of the wave depth, embedded length, yield strength, and flexural rigidity of the fiber.