Charcoal is a relative cheap source of energy for stoves and cauldrons, having the advantage of being neutral with respect to CO2 emissions. The conventional process to produce charcoal is through methods such as earth pits or brick kilns, in which the energy required to produce the carbonization is obtained from the combustion of a part of the wood, which leads to a considerable decrease in the net production of carbon, combined with lack of control of the temperature of the process, leading to products of lower quality and a maximum yield of 200-300kg per ton of wood used.In this paper we present the design of a solar oven capable of producing charcoal out of wood, together with its construction and evaluation. The design does not require solar tracking throughout the all-day.The prototype built has a collection surface of 1.37 m2, and can obtains 70g of charcoal out of 180g of wood, in approximately five hours, in a sunny day and with a typical irradiance of 800W/m2, which corresponds at an efficiency of 380kg per tonne

Low-resistance metal-to-metal contacts, both static and sliding contacts, are of interest to many scientific and technical applications as magnetic confinement fusion, railguns, and electrical motors. In fusion applications, silver-coated copper contacts and low-current-density designs are preferred, while in other applications, high current densities are required. For high-pressure high-current-density sliding contacts, contact pairs such as aluminum/copper are preferred as in railguns, while for electrical motors, copper–copper alloys are preferred. Copper–beryllium alloy, C172, is investigated as static contacts for high-current-density pulsed-power applications. To subject the contacts to suitable current pulses and pressures, a special electrical contact assembly has been developed allowing contact pressures from 0 to 66 MPa and current densities from 62 to 263 kA/cm ² . The contacts were studied under different current density pressure combinations with repeated 60- $\mu \text{s}$ pulses in air, while current evolution and surface modifications were followed. Besides some surface oxidation, no evidence of other surface modifications like welding or surface melting were found.

Fast neutrons can perform two functions that are critical to the nuclear power industry: breed fissile material from fertile material and burn minor actinides in spent fuel. The fusion reaction in a fusion reactor between deuterium and tritium nuclei yields an alpha particle and a neutron with 14.5-MeV energy. These neutrons can easily convert fertile material (such as 238U and 232Th) into fissile material (such as 239Pu and 233U) and destroy minor actinides (Pu, Np, Am, and Cm) present in the spent nuclear fuel and significantly reduce its radiotoxicity. However, each neutron generated implies one tritium consumed and tritium is generated by nuclear reactions between a neutron and lithium nuclei. Therefore, neutron economy becomes a crucial issue and an adequate neutronic modeling of the neutron source becomes critical. In this article, the Automatic System for TRansport Analysis (ASTRA) and Monte Carlo N-Particle (MCNP) codes are used in conjunction to characterize the neutron flux coming out of a low-aspect-ratio tokamak machine. ASTRA is first used to determine temperature and density profiles within the plasma volume and MCNP is used to evaluate the neutron flux. Since the simulation of an extended neutron source with complex geometry such as the confined plasma inside the tokamak is difficult, steps are taken to simplify the geometry by defining two simple sources, a cylindrical wall and a disk, which should have similar neutron emission distributions to the volumetric source. This reduction is done using a preprocessing Monte Carlo algorithm to establish probability density functions of neutron emission for the cylindrical wall as a function of the height and for the disk as a function of the radius, based on the emission characteristics of the extended source. The results that compare the neutron flux leaving a volume for four different configurations of neutron sources (isotropic source at the geometrical origin, ring source at the plasma geometrical center, cylindrical wall source, and distributed multipoint source) are presented. It is found that the processing of the two simple sources has a higher computational cost in terms of both processing time and random number consumption.

This article presents a performance assessment of an electrical power and cooling system powered by a parabolic dish collector and using refrigerants with low global warming potential. The study was conducted using energy and mass balances for each component and system. The simulation includes various parameters, such as solar radiation, the focal temperature of the solar collector, the ambient temperature, the power cycle pressure ratio, and the chiller’s evaporation temperature. The results show that the efficiency of the organic Rankine cycle with the refrigerant R1233zd(E) is similar to that of the refrigerants R123 and R245fa and is up to 11 and 50 times lower than with R290 and R744, respectively. The solar absorption chiller using the refrigerant R717 can achieve cooling with a supply temperature up to 5 °C lower than that of R718. The dynamic simulation results show that the energy efficiency of the proposed solar-powered generator–chiller is 14% higher than that of a standard solar-powered absorption chiller. Furthermore, the same solar-powered generator–chiller reduces the primary energy required by a conventional system by 60% (PESr = 0.60). The presented results may be useful for the design of sustainable generator–chillers for rural areas or for autonomous housing in tropical climates.