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Thermal energy storage units conventionally have the drawback of slow charging response. Thus, heat transfer enhancement techniques are required to reduce charging time. Using nanoadditives is a promising approach to enhance the heat transfer and energy storage response time of materials that store heat by undergoing a reversible phase change, so-called phase change materials. In the present study, a combination of such materials enhanced with the addition of nanometer-scale graphene oxide particles (called nano-enhanced phase change materials) and a layer of a copper foam is proposed to improve the thermal performance of a shell-and-tube latent heat thermal energy storage (LHTES) unit filled with capric acid. Both graphene oxide and copper nanoparticles were tested as the nanometer-scale additives. A geometrically nonuniform layer of copper foam was placed over the hot tube inside the unit. The metal foam layer can improve heat transfer with an increase of the composite thermal conductivity. However, it suppressed the natural convection flows and could reduce heat transfer in the molten regions. Thus, a metal foam layer with a nonuniform shape can maximize thermal conductivity in conduction-dominant regions and minimize its adverse impacts on natural convection flows. The heat transfer was modeled using partial differential equations for conservations of momentum and heat. The finite element method was used to solve the partial differential equations. A backward differential formula was used to control the accuracy and convergence of the solution automatically. Mesh adaptation was applied to increase the mesh resolution at the interface between phases and improve the quality and stability of the solution. The impact of the eccentricity and porosity of the metal foam layer and the volume fraction of nanoparticles on the energy storage and the thermal performance of the LHTES unit was addressed. The layer of the metal foam notably improves the response time of the LHTES unit, and a 10% eccentricity of the porous layer toward the bottom improved the response time of the LHTES unit by 50%. The presence of nanoadditives could reduce the response time (melting time) of the LHTES unit by 12%, and copper nanoparticles were slightly better than graphene oxide particles in terms of heat transfer enhancement. The design parameters of the eccentricity, porosity, and volume fraction of nanoparticles had minimal impact on the thermal energy storage capacity of the LHTES unit, while their impact on the melting time (response time) was significant. Thus, a combination of the enhancement method could practically reduce the thermal charging time of an LHTES unit without a significant increase in its size.

Thermal energy storage is a technique that has the potential to contribute to future energy grids to reduce fluctuations in supply from renewable energy sources. The principle of energy storage is to drive an endothermic phase change when excess energy is available and to allow the phase change to reverse and release heat when energy demand exceeds supply. Unwanted charge leakage and low heat transfer rates can limit the effectiveness of the units, but both of these problems can be mitigated by incorporating a metal foam into the design of the storage unit. This study demonstrates the benefits of adding copper foam into a thermal energy storage unit based on capric acid enhanced by copper nanoparticles. The volume fraction of nanoparticles and the location and porosity of the foam were optimized using the Taguchi approach to minimize the charge leakage expected from simulations. Placing the foam layer at the bottom of the unit with the maximum possible height and minimum porosity led to the lowest charge time. The optimum concentration of nanoparticles was found to be 4 vol.%, while the maximu possible concentration was 6 vol.%. The use of an optimized design of the enclosure and the optimum fraction of nanoparticles led to a predicted charging time for the unit that was approximately 58% shorter than that of the worst design. A sensitivity analysis shows that the height of the foam layer and its porosity are the dominant variables, and the location of the porous layer and volume fraction of nanoparticles are of secondary importance. Therefore, a well-designed location and size of a metal foam layer could be used to improve the charging speed of thermal energy storage units significantly. In such designs, the porosity and the placement-location of the foam should be considered more strongly than other factors.

There is no valid and well-established tool to measure fatigue in people with chronic hepatitis B. The aim of this study was to translate the Multidimensional Fatigue Inventory (MFI) into Persian and examine its reliability and validity in Iranian people with chronic hepatitis B. The demographic questionnaire and MFI, as well as Chronic Liver Disease Questionnaire and EuroQol-5D (to assess criterion validity), were administered in face-to-face interviews with 297 participants. A forward-backward translation method was used to develop a culturally adapted Persian version of the questionnaire. Cronbach's α was used to assess the internal reliability of the scale. Pearson correlation was used to assess criterion validity, and known-group method was used along with factor analysis to establish construct validity. Cronbach's α for the total scale was 0.89. Convergent and discriminant validities were also established. Correlations between the MFI and the health-related quality of life scales were significant (p < .01). The scale differentiated between subgroups of persons with the hepatitis B infection in terms of age, gender, employment, education, disease duration, and stage of disease. Factor analysis indicated a four-factor solution for the scale that explained 60% of the variance. The MFI is a valid and reliable instrument to identify fatigue in Iranians with hepatitis B.

Background: Quality of services, making communications with target groups, and educating them are among the most important success factors in implementation of family planning programs. Provision of public access to contraception and related methods, counseling services, and paying attention to social specification and cultures are important in promotion of service quality. With regard to applicability of health education theories and models, the present study aimed to find the impact of an educational program based on BASNEF model to choose contraceptive methods in women referring to health care centers in Minoodasht in 2012., Materials and Methods: This is a quasi-experimental study. Data were collected using BASNEF questionnaire by the researcher from women referring to health care centers in two groups of study and control (n = 100 in each group). Educational intervention (in the form of four educational 1-h sessions once a week during 1 month and two additional review sessions) was conducted in the form of group and face-to-face discussions and educational booklets were distributed. Data were analyzed by Chi-square, analysis of covariance (ANCOVA), paired t-test, and t-test through SPSS version 14., Results: After intervention, mean score of knowledge was significantly higher in the study group compared to control (P < 0.003). Intervention led to a better attitude in the study group (P < 0.0001). Mean score of subjective norms and enabling factors after intervention was significantly higher in the study group compared to control (P < 0.0001). The change in practice had a significant increase in the study group (54%) compared to control (9%)., Conclusions: BASNEF-based educational intervention was effective in increasing women's knowledge, attitude, and practice. As family and educational facilities are among the influencing factors on contraceptive method selection, interventional planning is hoped to be based on educational model.