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Objectives: The COVID-19 pandemic has had a profound impact on human social and economic structures, making it one of the most significant crises of the 21st century. The production and consumption of energy sources, such as electricity, oil, and gas, have also been affected by the pandemic. Therefore, this study aims to systematically review the effects of the COVID-19 pandemic on energy consumption. Methods: This study presents a systematic review of the impact of the coronavirus on energy consumption. Initially, relevant keywords were selected, and a systematic search of studies was conducted in databases including Web of Science, PubMed, Scopus, and ScienceDirect from 2020 to May 2022. Following screening, articles meeting the eligibility criteria were included in the study. Results: Through this systematic review, a total of 19,551 studies were identified, of which 18 met the eligibility criteria. All included studies investigated electricity consumption, while two studies focused on gas and fuel consumption, and only one study examined heating oil consumption. The most significant decreases in electricity, natural gas, and transportation fuel consumption were 55.4%, 32.4%, and 75.9%, respectively. On the other hand, heating oil consumption saw an increase of 12%. Conclusion: The results of this systematic review indicate that the COVID-19 pandemic has resulted in reduced energy consumption across various sectors, including electricity, transportation fuel, and natural gas, leading to a decrease in greenhouse gas emissions. However, some studies reported an increase in electricity consumption in the residential sector due to prolonged periods of staying at home and remote work during quarantine. [ABSTRACT FROM AUTHOR]

Background. Zirconia, with its excellent mechanical properties, has become a popular choice for esthetic and durable restorations due to the increasing demand of patients. It has overcome most of the limitations of all ceramic restorations. However, bonding to zirconia remains a challenge. Objectives. This study is aimed at assessing the effect of surface treatment with alkaline agents at two different temperatures on microshear bond strength (μSBS) of zirconia to composite resin. Materials and Methods. This in vitro, experimental study was conducted on zirconia blocks measuring 2 × 4 × 8 mm. The blocks were sandblasted with alumina powder and randomly assigned to 5 groups (n = 16 each). The blocks in groups 1 and 2 underwent surface treatment with sodium hydroxide (NaOH) and groups 3 and 4 with zirconium hydroxide (Zr(OH)4) at room temperature and 70°C. Group 5 served as the control group and did not receive any surface treatment. After the application of bonding agent and its light-curing, composite cylinders in plastic tubes were bonded to the surface of each block and cured. After incubation, they underwent μSBS test. Data were analyzed by one-way ANOVA and Tukey's test (alpha = 0.05). Results. The μSBS was significantly higher in all intervention groups than that in the control group (P < 0.05). The μSBS in Zr(OH)4 groups was significantly higher than that in NaOH groups (P < 0.05). The mean μSBS of heated groups was slightly, but not significantly, higher than the corresponding room temperature groups (P > 0.05). Conclusion. Surface treatment of zirconia with NaOH and Zr(OH)4 alkaline agents can increase its μSBS to composite resin; Zr(OH)4 was significantly more effective than NAOH for this purpose, but heating did not have a significant effect on μSBS. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the full repowering of a steam Power Plant with a capacity of 320 MW in Iran was evaluated technically and economically. Implementation of this plan for the target power plant was selected because of its over 30 years of age. Due to the presence of steam flash feed water preheaters and the possibility of preheating feed water entirely or partially prior to entering heat recovery steam generator, the effect of using or not using these low and high pressure equipment was evaluated in different cases. To do this, five different cases were proposed and reviewed. Considering the available gas turbines in Iran, the gas turbines models Siemens V94.2 and V94.3A were selected. In each case, the optimum point is obtained in terms of the lowest cost of electricity generation. Finally, after reviewing the results of all cases, full repowering plan with parallel feed water heating was selected as the best alternative in terms of energy and exergy efficiencies and the price of generating electricity. If two heat recovery steam generators and two V94.3A gas turbines are used, the net exergy and energy efficiencies for the cycle can reach 54.49% and 52.98%, respectively. Moreover, the power capacity of a repowered unit is equal to 700.44 MW with electricity generation price of 0.05986 $/kWh. Graphical abstract Image 1057 Highlights • In the present study, a real power plant has been studied (A Case Study). • The five different arrangements of feed water heaters for proposed scenarios have been considered. • The merging of water-gas heat exchangers with existing preheaters has been investigated. • Optimum techno-economic case for repowering has been presented. [ABSTRACT FROM AUTHOR]

Background and Objectives: Workers of the steel industry are exposed to many hazardous risks of nonfatal injuries and diseases considering the structure of their working environment. The aim of this study was to evaluate and identify the risks associated with the furnace in one of the north of Isfahan (Iran) Steel Complexes. Methods: The data were gathered through meeting sessions, observation, and documents surveys and were documented in failure modes and effects analysis (FMEA) worksheets. In this way, the weight of each failure was considered of risk priority number. Data surveys were documented in FMEA worksheets. Results: The results showed that explosion hazards and gas leaks were among the most dangerous hazards with the highest number of risks, respectively. After identifying the control measures and applying them, the percentage of identified risks is 77% at the acceptable level, 22.2% at the acceptable level under the condition of control, and 0% at the unacceptable level. Hazards found in workplaces were greater in the steel industries and iron industries. Conclusions: It can be concluded that education and training regarding related risk factors, providing personal protective equipment, and development of programs that can ensure safety in industries may lessen and prevent hazards associated with working place. [ABSTRACT FROM AUTHOR]

This paper assess the feasibility of using heating-cooling radiant panel in residential buildings in five different climate zones in Iran. This study leverages simulation modeling to evaluate the thermal performance of heating-cooling radiant panels. By defining new indices, applicability limiting factors of the radiant panels, i.e. condensation risk in cooling, and asymmetric radiation discomfort in heating are evaluated and compared in different climatic conditions. The system capacity and setpoints are calculated based on thermal comfort conditions, using PMV index in heating (PMV= -0.5) and cooling (PMV= +0.5) modes. Results of this study indicate that for dryer regions with less risk of condensation the radiant system can help home owners to save around 11.3% on their heating energy and 9.1% on cooling energy use. [ABSTRACT FROM AUTHOR]

Abstract: Iran is a country with five different climates and 50°C temperature difference between its warmest and coldest regions. In the present paper, the prime-mover capacity of a CCHP system for the same building in five different climates is determined. For this purpose, five cities from these climates are chosen and their weather information for the last five years is gathered from the Iran Metrological Organization. The hourly load of the five cities for the whole year is calculated and the maximum rectangle method is used to determine the size of the prime mover and the recommended full load operation time. The results show that the CCHP system saves energy during the whole year for all the climates. The yearly average fuel energy saving ratio of 37.85%, 33.16%, 30.75%, 29.60% and 25.30% are achieved for Chabahar, Ahwaz, Kamyaran, Tehran and Bandar Anzali, respectively. Furthermore, the analyses show that no heating system is needed for the cities of Chabahar and Ahwaz, but an auxiliary boiler is needed for all the climates to compensate the lack of heating or to support the absorption chiller. The sensitivity analysis shows that the hourly load of building is least sensitive to the minimum wet bulb temperature. [Copyright &y& Elsevier]

Optimum microclimate parameters, including air temperature (T), relative humidity (RH) and vapor pressure deficit (VPD) that are uniformly distributed inside greenhouse crop production systems are essential to prevent yield loss and fruit quality. The objective of this research was to determine the spatial and temporal variations in the microclimate data of a commercial greenhouse with tomato plants located in the mid-west of Iran. For this purpose, wireless sensor data fusion was incorporated with a membership function model called Optimality Degree (OptDeg) for real-time monitoring and dynamic assessment of T, RH and VPD in different light conditions and growth stages of tomato. This approach allows growers to have a simultaneous projection of raw data into a normalized index between 0 and 1. Custom-built hardware and software based on the concept of the Internet-of-Things, including Low-Power Wide-Area Network (LoRaWAN) transmitter nodes, a multi-channel LoRaWAN gateway and a web-based data monitoring dashboard were used for data collection, data processing and monitoring. The experimental approach consisted of the collection of meteorological data from the external environment by means of a weather station and via a grid of 20 wireless sensor nodes distributed in two horizontal planes at two different heights inside the greenhouse. Offline data processing for sensors calibration and model validation was carried in multiple MATLAB Simulink blocks. Preliminary results revealed a significant deviation of the microclimate parameters from optimal growth conditions for tomato cultivation due to the inaccurate timer-based heating and cooling control systems used in the greenhouse. The mean OptDeg of T, RH and VPD were 0.67, 0.94, 0.94 in January, 0.45, 0.36, 0.42 in June and 0.44, 0.0, 0.12 in July, respectively. An in-depth analysis of data revealed that averaged OptDeg values, as well as their spatial variations in the horizontal profile were closer to the plants' comfort zone in the cold season as compared with those in the warm season. This was attributed to the use of heating systems in the cold season and the lack of automated cooling devices in the warm season. This study confirmed the applicability of using IoT sensors for real-time model-based assessment of greenhouse microclimate on a commercial scale. The presented IoT sensor node and the Simulink model provide growers with a better insight into interpreting crop growth environment. The outcome of this research contributes to the improvement of closed-field cultivation of tomato by providing an integrated decision-making framework that explores microclimate variation at different growth stages in the production season. [ABSTRACT FROM AUTHOR]