Seismic stability of coal tailings dams with spatially variable and liquefiable coal tailings using pore pressure plasticity models

Failure of tailings dams can result in significant spill, loss of human lives, and damages to the environment and infrastructure. Cyclic loadings such as earthquakes and blasting are among the main threats to the stability of tailings dams. Seismic stability analyses of tailings dams are further challenged by the uncertainty and variability of tailings properties. In this paper, the influence of input motion characteristics and spatial variability in coal tailings (CT) properties on the seismic stability of a typical upstream-construction CT dam is investigated. Among the input motion characteristics, peak ground acceleration (PGA), equivalent number of cycles (ENC), and frequency content are the focus of this study. First, the applicability of two advanced constitutive plasticity models, PM4Sand and PM4Silt, in simulating the cyclic behavior of CT is evaluated and a suitable model is selected. The undrained shear strength of CT is modeled as a spatially correlated Gaussian random field. Six input motions — one blast and five earthquakes — are selected for the dynamic analyses. The dynamic analyses are conducted in co-seismic and then post-seismic stages. The seismic stability of the CT dam with uniform properties (i.e. uniform models) is compared to the stochastic models under the selected input motions. Post-seismic analysis was found critical for the stochastic models. This study highlights the importance of stochastic modeling and the consideration of spatial variability in seismic stability analysis of CT dams

Long-Term Resilient and Permanent Deformation Behavior of Controlled Low Strength Materials for Pavement Applications

The paper deals with the long-term stiffness characterization of Controlled Low-Strength Materials (CLSM) for pavement applications in substitution of granular fill materials. Three alternative CLSM mixtures, two with ordinary Portland cement and a third one with an ultra-rapid solpho aluminate cement, were examined. Two different sample aspect ratios were considered and the samples were subjected to different testing conditions in terms of saturation, loading time and repetition. The investigated CLSMs are insensitive to variations of loading frequency and to water saturation, and sensitive to sample aspect ratio. They exhibit a significant increase in stiffness under repeated load triaxial testing and a low permanent strain accumulation. Finally, they exhibit an increase in resilient modulus when the deviatoric stress increases

Advantages and Disadvantages of Methadone among Children and Adults: A Systematic Review and Meta-Analysis

Background: Today, an increasing trend to methadone as an alternative maintenance treatment for opiate dependence in adults is observed; children for both intentional and accidental reasons are exposed to serious and fetal effects of methadone. We aimed to investigate effects of methadone on children and sexual functioning among adults in Iranian population. Materials and Methods: An extensive search was done in databases of Medline, EMBASE, Scopus, Cochrane, and Web of Science until August 2018. Two independent researchers screened articles, and categorized them based on the evaluated outcomes and overall effect size was presented. After excluding the duplicated, irrelevant and low-quality articles, eligible ones were enrolled in the meta-analysis. Finally, pooled effect size was presented as standardized mean difference (SMD) or pooled prevalence with 95 confidence interval (95 CI). Results: Methadone was found to be more effective than morphine on neonatal abstinence syndrome. The first four most common symptoms of methadone poisoning were loss of consciousness (81), sleepiness (72), meiotic pupils (76), vomiting (56), and Apnea (48). The overall prevalence rate of sexual disorders and erectile dysfunction was 66.3 and 77.5, respectively. The subjects in methadone group were over 2.5-fold more likely to use condom during intercourse (p<0.001). The methadone therapy could lead to a significant reduction in orgasm functioning (p<0.001), and a significant improvement in libido (p=0.001). The methadone maintenance treatment (MMT) significantly resulted in decreased orgasm function and improved libido in males. Conclusion: Evidence suggests a positive impact of methadone maintenance treatment on risky sexual behaviors. Regarding the methadone poisoning effect on children, people should be informed by health care providers about serious and fetal effects on children

Psychometric Properties of the Pornography Craving Questionnaire (PCQ) in Iran

Objectives: Addiction to pornography is one of the most important behavioral addictions among Iranian youth. The purpose of this study was to develop and validate a measurement scale of �cravings for pornography� Iran. Methods: This Psychometric study was conducted on a 234 general Iranian population sample in 2017 with a random sampling method. In this study, the psychometric properties of the Persian version of the Pornography Craving Questionnaire were evaluated. Data were analyzed by exploratory factor analysis using SPSS version 23. The questionnaire was administered online (Telegram application and email). Results: The age range of 234 study participants was 13 to 51 years (mean = 29.7); 97 females (41.5) and 135 males (57.7). To determine this questionnaire�s cut-off value, we divided into three categories of low or no craving (12 - 36), average (36 - 60), and high (60 - 84). The result of exploratory factor analysis for these questions identified two factors (Psychological reactions and Desire). Cronbach�s alpha was 0.8. Conclusions: According to the results of this study, the Persian version of the �the pornography craving questionnaire� has sufficient reliability and validity in Iranian society. Copyright © 2020, Author(s)

Lightweight Copper–Carbon Nanotube Core–Shell Composite Fiber for Power Cable Application

The substitution of traditional copper power transmission cables with lightweight copper–carbon nanotube (Cu–CNT) composite fibers is critical for reducing the weight, fuel consumption, and CO2 emissions of automobiles and aircrafts. Such a replacement will also allow for lowering the transmission power loss in copper cables resulting in a decrease in coal and gas consumption, and ultimately diminishing the carbon footprint. In this work, we created a lightweight Cu–CNT composite fiber through a multistep scalable process, including spinning, densification, functionalization, and double-layer copper deposition. The characterization and testing of the fabricated fiber included surface morphology, electrical conductivity, mechanical strength, crystallinity, and ampacity (current density). The electrical conductivity of the resultant composite fiber was measured to be 0.5 × 106 S/m with an ampacity of 0.18 × 105 A/cm2. The copper-coated CNT fibers were 16 times lighter and 2.7 times stronger than copper wire, as they revealed a gravimetric density of 0.4 g/cm3 and a mechanical strength of 0.68 GPa, suggesting a great potential in future applications as lightweight power transmission cables