Effects of Freeze-Thaw Cycles on Axial Compression Behaviors of UHPC-RC Composite Columns.

Ultra-high performance concrete (UHPC) with excellent durability has broad application prospects in improving the durability of reinforced concrete (RC) structures. To clarify the influence of freeze-thaw cycles on the axial compression performance of UHPC-RC composite columns, axial compression tests were carried out on composite columns with different cycles (0, 100, 200, 300 cycles) and stirrup spacing (35, 70, 105 mm). The results showed that the UHPC shell did not fall off when the composite column was destroyed, even in the freeze-thaw environment. Under the action of freeze-thaw cycles, the peak load Nu,t and initial elastic modulus E of the composite column decreased, but the ductility coefficient µ increased. Increasing the stirrup spacing could significantly improve the ductility of the composite column. After 100 freeze-thaw cycles, the ductility coefficient µ of the 35 mm stirrup spacing specimen was 112.6% higher than that of the 105 mm specimen. A prediction model for the bearing capacity of UHPC-RC composite columns under freeze-thaw cycles was established, and the predicted results were in good agreement with the experimental results. This study lays a theoretical and experimental foundation for the application and design of UHPC-RC composite columns in the freeze-thaw environment.

Intimate Partner Violence Against Women Before, During, and After Pregnancy: A Meta-Analysis.

Intimate partner violence (IPV) against pregnant women negatively impacts women's and infants' health. Yet inconsistent results have been found regarding whether pregnancy increases or decreases the risk of IPV. To answer this question, we systematically searched for studies that provided data on IPV against women before pregnancy, during pregnancy, and after childbirth. Nineteen studies met our selection criteria. We meta-analyzed the nineteen studies for the pooled prevalence of IPV across the three periods and examined study characteristics that moderate the prevalence. Results showed the pooled prevalence estimates of IPV were 21.2% before pregnancy, 12.8% during pregnancy and 14.7% after childbirth. Although these findings suggest a reduction in IPV during pregnancy, our closer evaluation of the prevalence of IPV after childbirth revealed that the reduction does not appear to persist. The prevalence of IPV increased from 12.8% within the first year after childbirth to 24.0% beyond the first year. Taken together, we should not assume pregnancy protects women from IPV, as IPV tends to persist across a longer-term period. Future studies are needed to investigate if IPV transits into other less obvious types of violence during pregnancy. Moderator analyses showed the prevalence estimates significantly varied across countries by income levels and regions.

Online monitoring of fatigue damage in welded joints using diffuse ultrasound.

Fatigue damage is a common cause of failure in welded structures, and it is often difficult to detect it in the early stage. While ultrasonic-based methods can effectively monitor crack propagation, it remains a significant challenge to indicate the initiation of cracks. In this study, a novel method is proposed to monitor the diffuse ultrasonic field affected by ratcheting strain and microcracks formed in welded joints during fatigue degradation. The energy density in the diffuse ultrasonic signal is computed and correlated with different fatigue cycles, allowing for online monitoring of fatigue damage in welded joints. Six butt and cross-welded joints were studied under different fatigue conditions, and digital image correlation (DIC) technology was used for comparison throughout the fatigue tests. The results indicate that the correlation coefficient of the energy density in diffuse ultrasound exhibits a significant decreasing trend when crack initiation occurs, providing a unique signal to indicate crack initiation in welded joints. This signal may appear earlier than that from ratcheting strain monitored by DIC due to ultrasound's sensitivity to internal damages.

The Association Between Child Maltreatment and Pathological Narcissism: A Three-Level Meta-Analytic Review.

Emerging evidence has documented the positive association between child maltreatment and both phenotypes of pathological narcissism (i.e., vulnerable and grandiose narcissism). However, results across these studies are inconsistent. Therefore, the present meta-analysis aimed to examine the extent to which child maltreatment is associated with vulnerable and grandiose narcissism, and whether these associations differed by study or sample characteristics. A systematic literature review was conducted in Web of Science, ScienceDirect, PubMed, Google Scholar, and China National Knowledge Infrastructure. Three-level meta-analyses were performed in R to synthesize the effect sizes. A total of 15 studies (N = 9,141 participants) producing 129 effect sizes were included. Results showed that child maltreatment was positively related to both vulnerable narcissism (mean r = .198; p < .001) and grandiose narcissism (mean r = .087; p < .001), but only to a small extent. Further, the association between child maltreatment and vulnerable narcissism was stronger for neglect (r = .278) than for physical abuse (r = .130). The strength of the association between child maltreatment and grandiose narcissism was larger for samples that were on average younger than 18 years (r = .187) than for samples that were on average older than 18 years (r = .068). Also, the strength of the association was stronger for females than for males. Child maltreatment is a risk factor for developing both vulnerable and grandiose narcissism. Interventions targeting pathological narcissism should be aware of potential trauma resulting from victimization of child maltreatment.

Child Maltreatment as a Risk Factor for Rejection Sensitivity: A Three-Level Meta-Analytic Review.

Theoretical and empirical evidence has suggested that child maltreatment victimization is associated with rejection sensitivity. However, empirical evidence on this association is inconsistent. Therefore, this meta-analysis aimed to examine the overall association between child maltreatment and rejection sensitivity, and to investigate variables that may affect the strength of this association. Studies eligible for inclusion were searched in the databases: Web of Science, Science Direct, PubMed, MEDLINE, and China National Knowledge Infrastructure after which relevant studies were coded. Studies were synthesized in advanced three-level meta-analytic models in R. A total of 16 studies (N = 5,335 participants) yielding 41 effect sizes were included. Results showed that child maltreatment is significantly and positively related to rejection sensitivity (mean r = 0.230; p < .001), and to a small extent. Furthermore, this association is stronger for emotional abuse (r = 0.275) than for physical abuse (r = 0.157). It is not affected by the mean age and gender distribution of primary study samples nor by sample type (community sample versus clinical sample). It is concluded that child maltreatment is a risk factor for developing rejection sensitivity later in life. Therefore, interventions for rejection sensitivity should consider potential trauma resulting from prior child maltreatment experiences.

Mechanofluorochromic behaviours of functionalized carbazole-based difluoroboron compounds with different aryl substituents moieties.

To better understand the relationship between molecular structure and mechanofluorochromic characteristics, three carbazole-based N^O-chelated difluoroboron compounds (Cz-S-BF2 , Cz-PhNp-S-BF2 , and Cz-BNp-S-BF2 ) with different aryl substituents moieties were designed and synthesized. The mechanofluorochromic behaviours of Cz-S-BF2 (luminescence from bluish-green to yellowish-green, emission from 504 to 535 nm) without aryl substitution and Cz-PhNp-S-BF2 (luminescence from green and yellow, emission from 521 to 557 nm) with a phenyl-naphthalene group underwent reversible conversion using the grinding-fuming process. For Cz-BNp-S-BF2 this was not apparent due to the well coplanarity of the binaphthalene moiety. Mechanofluorochromic properties were demonstrated through XRD patterns measurement. We envisage that this study will provide a practicable reference to acquire organic molecules with mechanofluorochromic characteristics.

Associations between psychological inflexibility and mental health problems during the COVID-19 pandemic: A three-level meta-analytic review.

BACKGROUND: An increasing number of research has documented the positive associations between psychological inflexibility (PI) and mental health problems (i.e., depressive, anxiety, and stress symptoms) during the COVID-19 pandemic. However, the documented associations have been inconsistent. This review thus aimed to quantitatively summarize primary research to gain better estimates of these associations. METHODS: A systematic literature review was conducted in six databases and three-level meta-analytic models were used to statistically synthesize effect sizes and to examine moderators of the associations between PI and depressive, anxiety, and stress symptoms. RESULTS: A total of 22 studies yielded 63 effect sizes on associations between PI and depressive, anxiety, or stress symptoms. The results of three separate meta-analyses revealed a large and significant association between PI and depressive (r = 0.580, 95 % CI [0.549; 0.775]), anxiety (r = 0.548, 95 % CI [0.468; 0.761]), and stress symptoms (r = 0.548, 95 % CI [0.506; 0.725]). The association between PI and depressive symptoms is stronger for males than for females, and the association between PI and stress symptoms varies by type of measure that primary studies use to assess PI and stress symptoms. LIMITATIONS: Temporal or causal conclusions are not allowed due to cross-sectional nature of the associations included in meta-analyses. Clinical samples with high levels of stress were underrepresented. CONCLUSIONS: PI seems an important risk factor for symptoms of depression, anxiety, and stress, and should therefore be targeted in interventions addressing mental health problems during the COVID-19 pandemic and beyond.

Associations between self-disgust, depression, and anxiety: A three-level meta-analytic review.

Self-disgust is a negative self-conscious emotion that reflects disgust or revulsion directed toward oneself. A growing body of research has demonstrated a link between self-disgust, depression, and anxiety. However, the strength of these associations varied considerably across studies, suggesting the need to conduct a meta-analysis to produce a synthesized truer estimate. This review aimed to summarize the primary literature and improve our insight into these associations. The present study used three-level meta-analytic models to synthesize effect sizes and investigate potential moderators of the associations of self-disgust with depression and anxiety. The results revealed a significant association between self-disgust and depression (pooled r = 0.520, 95 % CI [0.485; 0.669], p < .001). The results also showed a significant and moderate association between self-disgust and anxiety (pooled r = 0.452, 95 % CI [0.419; 0.556], p < .001). These associations were held according to sex and age. In conclusion, this meta-analysis supports a moderate-to-large association between self-disgust, depression, and anxiety, suggesting that it is worthy of consideration in research and clinical practice.

Effect of Temperatures and Moisture Content on the Fracture Properties of Engineered Cementitious Composites (ECC).

This research will help to improve our understanding of the fracture properties of ECC at low temperatures (long-term low temperatures, freeze-thaw) and evaluate the safety properties of ECC under low-temperature conditions. Three levels of saturation (saturated, semi-saturated, and dry), four target temperatures (20, 0, -20, and -60 °C), and the effect of the coupled of the two on the mode I fracture properties of ECC were investigated. Then, we compared and analyzed the fracture properties of ECC loaded at 20 and -20 °C, after different freeze-thaw cycles (25, 50, 100 cycles), which were compared with saturated specimens without freeze-thaw at the four target temperatures to analyze the differences in low-temperature and freeze-thaw failure mechanisms. Temperatures and saturation have a significant effect on the fracture properties. Low temperatures and freeze-thaw treatments both decreased the nominal fracture energy of ECC. Distinct differences in matrix and fiber-matrix interface damage mechanisms have been discovered. Low temperatures treatment transforms ECC from a ductile to a brittle fracture mode. However, even after 100 freeze-thaw cycles, it remains ductile fractured. This study complements the deficiencies of ECC in low-temperature theoretical and experimental applications, and it sets the stage for a broad range of ECC applications.

Experimental Study on Biaxial Dynamic Compressive Properties of ECC.

An improved hydraulic servo structure testing machine has been used to conduct biaxial dynamic compression tests on eight types of engineered cementitious composites (ECC) with lateral pressure levels of 0, 0.125, 0.25, 0.5, 0.7, 0.8, 0.9, 1.0 (the ratio of the compressive strength applied laterally to the static compressive strength of the specimen), and three strain rates of 10-4, 10-3 and 10-2 s-1. The failure mode, peak stress, peak strain, deformation modulus, stress-strain curve, and compressive toughness index of ECC under biaxial dynamic compressive stress state are obtained. The test results show that the lateral pressure affects the direction of ECC cracking, while the strain rate has little effect on the failure morphology of ECC. The growth of lateral pressure level and strain rate upgrades the limit failure strength and peak strain of ECC, and the small improvement is achieved in elastic modulus. A two-stage ECC biaxial failure strength standard was established, and the influence of the lateral pressure level and peak strain was quantitatively evaluated through the fitting curve of the peak stress, peak strain, and deformation modulus of ECC under various strain rates and lateral pressure levels. ECC's compressive stress-strain curve can be divided into four stages, and a normalized biaxial dynamic ECC constitutive relationship is established. The toughness index of ECC can be increased with the increase of lateral pressure level, while the increase of strain rate can reduce the toughness index of ECC. Under the effect of biaxial dynamic load, the ultimate strength of ECC is increased higher than that of plain concrete.

Associations Between Rejection Sensitivity, Aggression, and Victimization: A Meta-Analytic Review.

BACKGROUND: Rejection sensitivity (RS) is a personality disposition characterized by oversensitivity to social rejection; individuals who are sensitive to social rejection tend to anxiously or angrily expect, readily perceive, and overreact to it. The associations between (a) RS and aggression and (b) RS and victimization have been studied in recent years. However, the strength of these associations varied considerably between studies. This review aimed to synthesize the primary literature to improve our insight into these associations. METHOD: A comprehensive literature search yielded 52 studies (with a total of 66,405 participants and producing 203 effect sizes) on the RS-aggression and RS-victimization associations. Three-level meta-analytic models were used to synthesize effect sizes and to examine potential moderators of the RS-aggression association and the RS-victimization association, respectively. RESULTS: There was a small but significant association between RS and aggression (pooled r = .183; p < .001) and a slightly below moderate and significant association between RS and victimization (pooled r = .298; p < .001). The RS-aggression association was stronger for angry RS than for anxious RS and stronger for reactive aggression than for proactive aggression. Similar results were obtained in analyzing the longitudinal associations only. CONCLUSIONS: RS is significantly associated with aggression and victimization. The implications of the results for clinical practice as well as directions for future research are discussed.

Controllable Synthesis of Zn-Doped α-Fe2O3 Nanowires for H2S Sensing.

One-dimensional Zn-doped α-Fe2O3 nanowires have been controllably synthesized by using the pure pyrite as the source of Fe element through a two-step synthesis route, including the preparation of Fe source solution by a leaching process and the thermal conversion of the precursor solution into α-Fe2O3 nanowires by the hydrothermal and calcination process. The microstructure, morphology, and surface composition of the obtained products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the formation process of α-Fe2O3 is significantly influenced by the introduction of Zn2+. The gas sensing measurements indicated that the sensor based on 1% Zn-doped α-Fe2O3 nanowires showed excellent H2S sensing properties at the optimum operating temperature of 175 °C. Notably, the sensor showed a low H2S detection limit of 50 ppb with a sensor response of 1.5. Such high-performance sensing would be ascribed to the one-dimensional structure and high specific surface area of the prepared 1% Zn-doped α-Fe2O3 nanowires, which can not only provide a large number of surface active sites for the adsorption and reaction of the oxygen and H2S molecules, but also facilitate the diffusion of the gas molecules towards the entire sensing materials.

The Childhood Maltreatment Modulates the Impact of Negative Emotional Stimuli on Conflict Resolution.

It has been reported that negative emotional stimuli could facilitate conflict resolution. However, it remains unclear about whether and how the impact of negative emotional stimuli on conflict resolution varies depending on childhood maltreatment. To clarify this issue, seventy-nine subjects were required to perform an arrow Eriksen Flanker Task which was presented in the center of emotional pictures. The present study found a significant interaction effect of childhood maltreatment and emotion on executive attention scores in reaction times (RTs) that reflect conflict resolution speed. For subjects in high childhood maltreatment, negative pictures elicited smaller executive attention scores in RTs than neutral and positive pictures, while neutral and positive pictures elicited similar executive attention scores in RTs. By contrast, for subjects in low childhood maltreatment, executive attention scores in RTs were similar across three conditions. These results suggest that the speed of conflict resolution is enhanced in high, instead of low, childhood maltreatment in situations of negative stimuli. This finding extends our understanding of the interaction among emotion, childhood maltreatment and conflict resolution.

Research on the Crack Risk of Early-Age Concrete under the Temperature Stress Test Machine.

A new temperature stress test machine (TSTM) was developed to improve temperature control accuracy and efficiency. As there is no uniform standard for the threshold value of TSTM, quite different threshold values are used in the test, which results in the influences of the threshold value on the evaluation of thermal stresses and crack risk of concrete not being determined. To illustrate the importance of an appropriate threshold value, different threshold values were used to evaluate the influences on the thermal stresses and cracking resistance of concrete specimens under a complete restraint test with semi-adiabatic temperature development. The results show that the maximum compressive stress of a concrete specimen with a threshold value 3 µÎµ was slightly larger than that of 1.5 µÎµ when the growth rate of tensile stress of the concrete specimen with the threshold value 3 µÎµ was slightly greater than that of concrete specimen with the threshold value 1.5 µÎµ. Based on the combination of crack risk coefficient and restraint degree, a new system for evaluating the crack resistance of concrete was proposed, in which different threshold values were used to estimate their influences on the crack risk of concrete. Thus, an appropriate range of threshold values could be determined.

Associations between rejection sensitivity and mental health outcomes: A meta-analytic review.

Rejection sensitivity is a personality disposition characterized by oversensitivity to social rejection. Using a three-level meta-analytic model, 75 studies were reviewed that examined associations between rejection sensitivity and five mental health outcomes: depression, anxiety, loneliness, borderline personality disorder, and body dysmorphic disorder. The results showed significant and moderate associations between rejection sensitivity and depression (pooled r=0.332; p<0.001), anxiety (pooled r=0.407; p<0.001), loneliness (pooled r=0.386; p<0.001), borderline personality disorder (pooled r=0.413; p<0.001), and body dysmorphic disorder (pooled r=0.428; p<0.001). The associations between rejection sensitivity and depression, anxiety, and borderline personality disorder varied by type of sample, but the associations were similar for clinical and non-clinical (i.e., community) samples. The association between rejection sensitivity and anxiety was negatively moderated by percentage of females in samples. The association between rejection sensitivity and depression was negatively moderated by length of follow-up. The longitudinal associations between rejection sensitivity and depression, anxiety, and loneliness were stable over time. Implications of the findings for both risk assessment and prevention and intervention strategies in mental health practice are discussed.