An experimental study of solar cooker performance with thermal concentrator system by spot Fresnel lens

Blood perfusion is defined as the volume of blood flowing through units of tissue volume per second. In thermoregulation, blood perfusion is a factor that affects heat transfer in the body, the greater the rate of blood perfusion will complicate the distribution of temperature throughout the body. In the study of bioheat transfer, heat transfer in the human body can be used as a therapy. At therapeutic temperatures (above 40°C), cells will die and stop their growth or commonly called hyperthermia therapy. It can allow thermonecrosis in body tissues and can be useful for tumour tissue. Of the various types of hyperthermia therapy, interstitial hyperthermia therapy is considered more effective because heat is directly delivered to tumour tissue to minimize other tissues exposed to therapeutic temperatures. Currently, there are no studies that study the effect of blood perfusion on the treatment of interstitial hyperthermia, even though blood perfusion greatly affects the temperature distribution in the human body/ In this study, heat transfer analysis will be performed on five layers of the human body, namely the epidermis, dermis, fat, muscle, and bones with interstitial application of hyperthermia therapy and affected by blood perfusion with a value of (8x10-4; 4x10-4; 2x10-4; 1x10-3; and 2x10-3)/s completed using finite element method with unsteady conditions in two axial dimensions. The part of the tumour studied is a tumour in the arm (forearm) in the span of 600s. This study shows that blood perfusion affects the value of temperature distribution in five layers of the body in unsteady conditions. The greater the value of blood perfusion flowing in the body, the more difficult the temperature will be to transmit because the blood distributes heat throughout the body faster, the difference between blood perfusion values is quite significant.

Because of the fickle nature of the renewable sources of energy production, professionals in this sector have developed hybrid renewable energy systems (HRES) that offer a constant and stable load supply. This research intends to build off-grid hybrid energy systems (HES) in Malang, Indonesia, that uses a solar generator, wind turbine, and biogas to power public buildings. The HOMER program was used to construct this model. Following the computations, multiple hybrid renewable energy system models are used to analyze each component’s capital cost and also cost of energy (COE). Furthermore, energy output, gas emissions, and a thermoeconomic assessment of several HRES models have been explored. Two ideal HRES models were evaluated: one with a biogas generator and one without. According to the research, employing a generator of biogas would reduce fuel consumption and emissions by 68.3%. This HRES model is impressive in light of Malang’s severe air pollution. Switching from diesel to biogas generator decreases NPC by 6.84%, according to the data.

This study aims to develop a sustainable technology-based Adiwiyata program implementation model to shape the characteristics of environmentally conscious students in Probolinggo City. Using a quantitative approach with the Structural Equation Modeling (SEM) method, this study analyzed the relationship between school policies, government involvement, technological innovation, student character formation, and the sustainability of Adiwiyata schools. The study population consisted of schools in Probolinggo City involved in the Adiwiyata program, with a sample of 200 respondents, including principals, teachers, and students. The results showed that technological innovation acts as a significant mediating variable between school policies and government involvement in shaping students’ character and the sustainability of Adiwiyata schools. Strong school policies and government involvement through regulations and technical training have been shown to increase the effectiveness of the Adiwiyata program, especially with the support of technology. The technological innovations implemented, such as energy management and communication platforms, have been shown to increase students’ environmental awareness and active participation in environmental activities. These findings have important implications for educational policy and environmental program management in schools. Recommendations include the need for increased government regulatory support for technology integration in schools as well as the development of school policies that prioritize all school members’ active participation in technology-based environmental programs. Further studies are required to explore the long-term impact of technology implementation on environmental education in other schools in Indonesia.

This study presents the strategy of controlling the air discharge in the prototype of small scale compressed air energy storage (SS-CAES) to produce a constant voltage according to the user set point. The purpose of this study is to simplify the control of the SS-CAES, so that it can be integrated with a grid based on a constant voltage reference. The control strategy in this study is carried out by controlling the opening of the air valve combined with a servo motor using three intelligence control systems (fuzzy logic, artificial neural network (ANN), and adaptive neuro-fuzzy inference system (ANFIS)). The testing scenario of this system will be carried out using two scenes, including changing the voltage set point and by switching the load. The results that were obtained indicate that ANN has the best results, with an average settling time of 2.05S in the first test scenario and 6.65S in the second test scenario.

Coconut oil premixed combustion behavior has been studied experimentally on perforated burner with equivalence ratio (φ) varied from very lean until very rich. The results showed that burning of glycerol needs large number of air so that the laminar burning velocity (S_L) is the highest at very lean mixture and the flame is in the form of individual Bunsen flame on each of the perforated plate hole. As φ is increased the S_L decreases and the secondary Bunsen flame with open tip occurs from φ =0.54 at the downstream of perforated flame. The perforated flame disappears at φ = 0.66 while the secondary Bunsen flame still exist with S_L increases following that of hexadecane flame trend and then extinct when the equivalence ratio reaches one or more. Surrounding ambient air intervention makes S_L decreases, shifts lower flammability limit into richer mixture, and performs triple and cellular flames. The glycerol diffusion flame radiation burned fatty acids that perform cellular islands on perforated hole. Without glycerol, laminar flame velocity becomes higher and more stable as perforated flame at higher φ. At rich mixture the Bunsen flame becomes unstable and performs petal cellular around the cone flame front. Keywords: cellular flame; glycerol; perforated flame;secondary Bunsen flame with open tip; triple flame