Viologens (N-mono- and N,N '-disubstituted-4,4 '-bipyridiniums) are among the most extensively studied redox-active materials due to their reversible electrochemical reduction into deeply colored radical species, making them attractive for electrochromic applications. However, most research has focused on solution-based systems or amorphous polymer composites, which limits their integration into electronic devices. To expand their application range, we incorporated electrochemically active monosubstituted viologens into a crystalline solid-state framework as building blocks of a permanently porous metal-organic framework (MOF), {[Ni3F(cpb)(3)(bdc)(1.5)]& centerdot;guests}(n) (Hcpb & centerdot;Cl = 1-(4-carboxyphenyl)-4,4 '-bipyridinium chloride; H(2)bdc = benzene-1,4-dicarboxylic acid). We demonstrate that this MOF can be grown as thin films on conductive substrates via a simple solvent-mediated process. The MOF's high void space (>80%) enables efficient ionic mobility for reversible switching between transparent and colored states at a low driving voltage of 1.0 V. While electrochromic behavior in viologen-based MOFs has been rarely explored, this work represents one of the first examples of a permanently porous viologen MOF exhibiting robust and reversible electrochromism. The synergy between nanoporosity, which facilitates electrolyte penetration, and the redox-active ligand's low-voltage response positions this material as a promising candidate for smart windows and electrochromic display technologies
Objective: Children who witness intimate partner violence (IPV) from caregivers are at a higher risk of maltreatment. Despite their interconnected nature, child maltreatment (CM) and IPV have often been studied and addressed in isolation, overlooking the complexity of "polyvictimization"-the multifaceted victimization experienced by many children. This study investigates the concurrence of maternal IPV victimization and mother-perpetrated CM, with a focus on identifying profiles of dual exposure, associated risk factors, and examining the long-term effects on children's behavioral regulation. Method: To identify patterns of co-occurrence in various forms of CM at age 3, a person-centered approach utilizing latent class analysis was applied. Data were extracted from the Future of Families and Child Wellbeing Study (N = 2,192). We used mothers' self-reported IPV experiences and maternal CM behaviors, including only those who reported at least one of the two forms. Results: Five classes emerged: (a) maternal emotional IPV only (53.7%), (b) maternal emotional IPV and psychological CM (27.8%), (c) maternal emotional IPV and neglect (10.9%), (d) maternal emotional IPV and physical CM (4.5%), and (e) maternal multifaceted IPV and neglect (3.0%). Factors distinguishing classes included maternal depression, parenting stress, material hardship, child sex, and neighborhood violence. Children's behavioral regulation at ages 5 and 9 varied across classes. Children exposed only to emotional IPV demonstrate relatively higher behavioral regulation compared to those experiencing more severe or multifaceted adversity. Conclusions: The findings emphasize the necessity of targeted, trauma-informed interventions to address the unique combinations of maternal IPV and CM. Mitigating contextual risk factors is crucial for reducing IPV and CM.
Advanced membrane technologies are promising for improving the efficiency and sustainability of energy-intensive chemical processes. In the Haber-Bosch process, membranes can reduce reliance on condensation and refrigeration units, lowering energy use and CO2 emissions. Inorganic NH3-permeable membranes provide better thermal stability than polymeric membranes for high-temperature applications. Recent studies show that ZnCl2-immobilized molten salt (IMS) membranes achieve NH3/N2 and NH3/H2 selectivities over 107 at similar to 300 degrees C. Previous research focused only on atmospheric pressure for total feed pressure. This study uniquely explores the NH3 separation properties of ZnCl2 IMS membranes under high-pressure conditions. The IMS membrane was prepared by forming a molten ZnCl2 in and above the pores of stainless-steel wire mesh supports. Characterization via TG-DTG-DSC techniques revealed that ZnCl2 could be used for IMS membranes between 310 and 400 degrees C without experiencing extreme thermal degradation. NH3 permeation tests were carried out on the IMS membrane using feed gas of NH3/N2 mixtures at pressures up to 450 kPa and helium sweep gas in the permeate at the same pressures. By maintaining equal total pressure at the retentate and permeate side, the IMS membrane exhibited an NH3 permeance of similar to 400 GPU at a total feed pressure of 450 kPa with NH3/N2 mixtures.
This paper presents a modified Goldak heat source (GHS) model applied to duplex stainless steel (DSS) wall-of-weld (WoW) and AA5356 aluminum in wire arc additive manufacturing (WAAM) using gas metal arc welding. Although prior modifications to the GHS exist, none have addressed the actual arc origin following arc initiation. Consequently, maintaining realistic parameter ranges in the standard GHS often results in artificially high temperatures, inconsistent interlayer boundaries, or large relative errors compared to experimental data. In this study, an arc origin offset (as a new Goldak parameter, Z(0)) is introduced in the double ellipsoidal heat source equations, reflecting the actual location of peak heat input. As a result, Z(0) improves the prediction of solid-liquid phase transitions of the melt pool crosssectional geometry validated by the macrographs. A thermal study optimizing this parameter, alongside a parametric study of this Modified GHS (MGHS), is first implemented on DSS-WoW and subsequently on the AA5356-WoW. The standard GHS and the MGHS are compared in each case and validated against experimental results and DSS macrographs. The results demonstrate how Z(0) enhances standard GHS and, more importantly, adjusts it to WAAM beyond a single weld bead. Additionally, an experiment conducted by the authors on an AA1100 Tube-to-Weld using a moving pyrometer (MIKRON-ME-PI 140) accurately confirmed the MGHS model. To estimate the Z(0) value in a more generalized way, a novel dimensionless number was developed to empirically relate Z(0) to five alloys and process parameters. This enables researchers and engineers to select the desired Z(0) value.
Supplementary cementitious materials (SCMs) are often used in concrete to reduce the risk of alkali-silica reaction (ASR), primarily through alkali dilution and binding. However, the effectiveness of SCMs with high alkali content (e.g., Na2Oeq > 3.0 wt.
