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• The systematic review suggests a positive link between volunteering and cognition. • Gender and education level may influence the relationship between volunteering and cognition. • Further research is needed to establish definitive conclusions on volunteering's cognitive benefits. This systematic review aims to examine the relationship between cognition and volunteering in older adults, with a specific focus on domain-specific outcomes. In April 2023, a comprehensive search was conducted across multiple electronic databases including PubMed, Google Scholar, ScienceDirect, Web of Science, and Scopus. The inclusion criteria for the study were limited to longitudinal studies or randomized controlled trials (RCTs). The quality and risk of bias of the included articles were assessed using the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT). Out of 3575 articles retrieved, 17 studies were eligible for inclusion in this review. The majority of these studies were conducted in high-income countries. Of the 17 studies reviewed, 16 found a positive association between volunteering and cognitive benefits. The analysis of seventeen studies meeting the predefined inclusion criteria suggests a potential positive correlation between volunteering and cognitive function among older adults. Some demographic factors such as gender and education level were observed to have an influence on this relationship. It was found that older adults who engage in volunteering may exhibit better episodic memory, working memory, and verbal fluency compared to non-volunteers. However, due to limitations in the existing research and variations across studies, further investigation is needed to establish definitive conclusions. [ABSTRACT FROM AUTHOR]

• Intergenerational ties aid elderly cognitive health. • Emotional and financial relationships help elderly's cognitive function. • More research needed on how visits from children impact elder cognitive health. As individuals age, cognitive decline can significantly impact their quality of life. This systematic review aims to investigate the potential association between parent-child relationships among older adults in Eastern Asian countries and their cognitive performance. For this research, a systematic search was conducted on several electronic databases including PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar search engine, up to March 2023. Out of 418 articles, 6 were eligible for inclusion in the study. The findings suggest that intergenerational relationships, particularly emotional support and two-way financial communications, are associated with maintaining cognitive health in older adults. Intergenerational relationships affect cognitive health in older adults, with implications for healthcare, social welfare, and the economy. Further research is required to investigate the effects of children's visits on cognitive health and explore the complexities of intergenerational relationships on cognitive health in aging populations. [ABSTRACT FROM AUTHOR]

Molecular dynamic simulations have been served to investigate various properties of methane/water system at two extreme conditions: away from hydrate formation and threshold it. The results that compare the two conditions have been discussed in the terms of surface tension, mean square displacement (MSD), diffusion coefficient, radial distribution function and thermodynamic functions. Investigation over a timescale of 500 ps demonstrated that the thermodynamic functions at 275 K and high pressures (corresponding to the hydrate formation threshold) are smaller than that of at 298 K, implying that the hydrate formation threshold is more stable. An increase in the system pressure and temperature leads to a decrease in the surface tension because of decreasing the intermolecular attractive forces. Besides, the comparison of oxygen–oxygen, carbon–carbon and carbon-oxygen radial distribution functions at temperatures of 275 and 298 K has been indicated that the height of peaks decreases due to increasing the temperature, demonstrating that the system become more stable at the threshold of hydrate formation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The adsorption and separation properties of new siliceous zeolites were investigated. [•] The force fields of COMPASS, PCFF, CVFF, DREIDING and Universal were used in the GCMC. [•] The PCFF is the best force field for simulation of adsorption in zeolites. [•] RWY zeolite is the best zeolite types for the separation of binary mixture. [Copyright &y& Elsevier]

Abstract: Structural, physical and separation properties of polyurethane membrane were investigated by configuration bias grand canonical Monte Carlo and molecular dynamic methods and the effects of degree of polymerization on these properties were studied. To understand the effect of degree of polymerization of polyurethane membrane on its separation property, the adsorption of furfural as pure and binary mixture with water was studied for polyurethane membrane with varied degrees of polymerization from 5 to 100. The temperature range for simulation calculation was 298 K–360 K and the pressure range was 0–10 bar. Also the effects of feed composition, density and free volume of polyurethane membrane on its separation property were studied. It was found that the adsorption of furfural and water in polyurethane membrane depends on free volume of polyurethane and this dependency is more significant for the adsorption of water molecule. The results indicate that the maximum adsorption of furfural and water occurs on polyurethane membrane with polymerization degree of 10. [Copyright &y& Elsevier]

Abstract: Grand Canonical Monte Carlo simulation is used to study adsorption of nitrogen on new type of zeolites such as IHW, IWV, SIV, UFI, and MSE at temperature range 273–325K and pressures up to 50bars. The optimum parameters of Lennard–Jones potential are evaluated and their effects on the simulation results are examined. Besides, the effects of temperature, pressure, framework density (FD) and oxygen density in unit cell on the adsorption isotherms are investigated. Although, the adsorption of nitrogen is a complex function of pressure, temperature, and pore structure of zeolite, it is found that, at room temperature, the adsorption increases linearly with increasing pressure. The results show that IWV type of zeolite gives the greatest adsorption at sufficiently high pressure. At low pressure, the effect of oxygen density in simulation box on the adsorption isotherms is higher than pore diameter. At high pressure, the effect of temperature on the adsorption isotherm does not depend on structural composition of zeolites. [Copyright &y& Elsevier]

• Reverse non-equilibrium molecular dynamics simulations (RNEMD) is used to investigate thermal conductivity of Polyamide 6. • Thermal conductivity of Polyamide 6 increases with the Degree of Polymerization (DOP) and reaches a constant value at high DOPs. • Polydispersity Index (PDI) does not have a significant influence on the thermal conductivity of the Polyamide 6. • The thermal conductivity increases linearly with the density. • The thermal conductivity is highly affected by the Fraction of Free Volume (FFV) of the system. In this study, the influence of both molecular weight (expressed as the degree of polymerization (DOP)) and Polydispersity index (PDI) on the thermal conductivity of Polyamide 6 (Nylon 6) were investigated by means of reverse non-equilibrium molecular dynamics simulations (RNEMD). At first, physical properties such as density and the solubility parameter were calculated to confirm the accuracy of the simulation results. Afterwards, variations in thermal conductivity with DOP and PDI were investigated. The simulation results show that the thermal conductivity of Polyamide 6 is 0.25 ± 0.002 W/(mK) which is in good agreement with the experimental data of 0.24–0.25 W/(mK). In addition, based on the simulation results, the thermal conductivity of Polyamide 6 has increased with the DOP and a plateau has been achieved at high DOPs. It was observed that varying PDI does not have a significant effect on the thermal conductivity at a constant value of average molecular weight. The dependency of thermal conductivity to the polymer density was also investigated and it was observed that by enhancing the polymer density, the thermal conductivity increases linearly. It was also concluded that the thermal conductivity is severely affected by system's fraction of free volume. [ABSTRACT FROM AUTHOR]

• MD simulation was applied to study the kinetics of methane hydrate growth. • A kinetics model based on the non-equilibrium thermodynamics was considered. • Two-parametric model had a constant parameter in all the operational conditions.. • The hydrate formation is a process proceeding on a natural path. In the present work, the molecular dynamic simulation was applied for studying the kinetics of methane hydrate growth. Several parameters such as the changes of potential energy, the MSD of molecules, the number of methane molecules near the solid/liquid interface and the position of liquid/solid interfaces with time were considered. The results showed that the potential energy and MSD of molecules in the layers near the interfaces significantly decreases implying that the growth proceeds in these layers. The maximum rate of growth or migration of methane molecules to the interfaces is observed around 2 ns. Moreover, a kinetics model was considered to predict hydrate growth kinetics. It is based on the irreversible and non-equilibrium thermodynamics and the concept of the thermodynamic natural path. The proposed model is a two-parametric model that one parameter was estimated to be a nearly constant value in the range from −1.05 to 1.46, but another one is a kinetic parameter dependent on the operational conditions. The model can well predict the entire process of hydrate formation, since the affinity, as a driving force of the process, shows that the hydrate formation is a process proceeding on a natural path. [ABSTRACT FROM AUTHOR]

Abstract The formation of organic sediments, especially asphaltene in reservoirs, wells and equipment, has a harmful effect on the oil production economy, which reduces oil production and can block oil production facilities. In order to investigate the asphaltene aggregation and solubility, a series of molecular dynamics simulations in different conditions were performed on two famous asphaltene based model, of M1 and VI. VI asphaltene has two high aliphatic side chains, whereas M1 asphaltene has only two methyl groups on its sides. The simulation results show that the solubility parameter increases with increasing number of aromatic rings and decreasing the number of carbon atoms in the side chain. The aggregation of asphaltene molecules in toluene, heptane and isopropyl benzene solvents and also in the mixture of solvents has been investigated. The results show that the aggregation of M1 asphaltene in toluene and isopropyl benzene is lower than that of VI asphaltene. The mixture isopropyl benzene-heptane is appropriate solvent for both asphaltenes M1 and VI which represents less interaction between asphaltene molecules. The effect of six types of inhibitors on the aggregation of asphaltene was investigated. Based on the simulation results, the aggregation of asphaltene with the presence of DETPMP inhibitor significantly decreases due to the delay in the growth of crystals and by increasing the concentration of all used inhibitors, their inhibitory properties were decreased. Graphical abstract Image 1 Highlights • Aggregation of asphaltene was studied by molecular simulation. • Relationship solubility parameter and asphaltenes structure were studied. Solubility parameter of pure asphaltene and different solvents were calculated. • Effects of inhibitors on the aggregation of asphaltene were studied. [ABSTRACT FROM AUTHOR]

Removal of cadmium ions from an aquatic solution was investigated by low-cost adsorbents and compared when modifying them by Fe-S nanoparticles. Nanocomposites were synthesized by a new experimental method under simple and inexpensive procedure by Fe-S nanoparticles, which possessed good characteristics of the surface area and magnetic property. These nanocomposite adsorbents removed cadmium at larger percentages than pure adsorbents. Iron filings had only a minor effect on the removal of cadmium, but when they were modified with Fe-S nanoparticles, the adsorption rate reached over 98.5%. Under operating conditions of pH 7, a concentration of 3 ppm, and a flow rate of 5 ml/min, the highest cadmium adsorption in water was caused by the iron nanocomposite. Display Omitted [ABSTRACT FROM AUTHOR]