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Energy hub concept has been emerged as a suitable tool to analyze multi-carrier energy systems. Deregulation and increasing competition in the energy industry have provided a suitable platform for developing the energy systems composed of competing energy hubs. Planning of energy hubs considering the competition between the hubs has not been sufficiently addressed, yet. A model has been proposed in this study for planning of a multi-hub energy system considering the competition between the hubs. The hubs are interconnected via an electric transmission system. While the heat demand for each hub must be supplied by deploying associated technologies, the electricity demand can be fulfilled by investing in technologies or exchanging through the transmission system considering the market price and line loading limits. A linear model has been developed to determine the optimal capacity development of heat and electricity generation technologies for energy hubs in a multi-period planning horizon to meet the heat and electricity demand for the defined load zone. The problem has been formulated and solved using Karush–Kuhn–Tucker (KKT) conditions. Once solved, the optimal capacity development in the hubs is determined as well as the amount and price of electricity interchange between the hubs for the load zones of the planning horizon. The proposed model has been applied to 3-Hub and 5-Hub energy systems. The effect of renewable generation and storage system have also been evaluated. The result have been presented and discussed to evaluate the validity of the results as well as the capabilities of the proposed model. It was observed that, due to the competition between the hubs, the electricity generation capacity in a hub can reach 23% higher that the peak demand of the same hub. The electricity price between the hubs differs by 25% while the difference between the gas price of the hubs is about 5 percent. It has also been observed that inclusion of renewable generation or storage technologies can alter the electricity generation capacity by 63 percent in HUB2., International Journal of Sustainable Energy Planning and Management, Vol. 30 (2021)

Purpose food handlers have an important role in transmitting pathogens from raw materials to cooked ones. This study was conducted to determine the knowledge, attitude, and practice (KAP) of 95 food handlers on five keys to safer food based on World Health Organization questionnaires in semi-industrial catering in a government office in Tehran. Materials and methods specialists reviewed the validity of questionnaires and reliability was measured using determination of inter rater agreement, relevancy and clarity of each question, and the tool as a whole was evaluated by the content validity method. The Cronbach’s alpha and repeatability were measured with intra-cluster correlation through repeated test-piloting after one month. Results In spite of good levels of KAP, lack of knowledge was observed in some items such as cooking thoroughly and keeping food at safe temperatures. All of the participants had good knowledge about washing hands (100% correct answers) and Low level of knowledge with 46.3% correct answers belonged to put cooked meat at room temperature question; in attitude section, 99% of the food handlers were regarded a positive attitude about the cleaning of surface in the kitchen to reduces the risk of illness; a worrying issue is 57% of participants agreed that by looking at foods can distinguish safe and spoiled ones finally 100% of the respondents were considered to have good behavior. Significant relations were found between knowledge and attitude (p