• Energy Research

Abstract This work test the feasibility and characterize the thermohygric properties of composite materials, realized with eco-friendly raw materials and designed to make suspended ceilings or interior partition walls. Several raw materials are considered: recycled paper (granules or cellulose wadding) and wood fibers. Aggregates or fibers are bonded with organic or mineral binder. One of the binder considered is starch, due to its availability in Ivory Coast (cassava flour). The calcium sulfate hemihydrate is also used for comparison. The density of the produced composites ranges from 400 to 1200 kg/m3 depending on formulation. The thermal conductivity increases proportionally with the density and ranges from 0.09 to 0.5 W/(m.K). The characterization of hygric behavior is based on the measurement of moisture buffer value (MBV) [1]. The hydric performances of the composites made of mineral binder goes from moderate (MBV around 1 g/(m².%RH)) to excellent (MBV > 2 g/(m².%RH)). The moisture buffer value of the paper granules -starch composite is also excellent (MBV > 2 g/(m².%RH))

Humanity’s long-term presence in space entails the establishment of sustainable space ecosystems in both orbital and planetary environments. Sustainable ecosystems are characterized by minimal resource depletion, reduction in space debris, reusable and renewable materials and components, among other factors. However, achieving sustainability in space is challenging due to limited resources, harsh environmental conditions, and the need for continuous operation. Intelligent robotic systems with diverse manipulation and locomotion capabilities using artificial intelligence (AI) are capable of In-Situ Resource Utilization and carrying out autonomous production and maintenance operations. Modular reconfigurable systems and heterogeneous teams allow for optimized task allocation strategies, thus expanding the task domain. Efficient human–robot interaction methods can assist astronauts and future space inhabitants in their routine tasks as well as during critical missions. We also emphasize the importance of collaboration among space agencies, roboticists and AI scientists for shared resources and knowledge, and the development of technology standards and interfaces for systems collaboration. Such cooperative efforts are vital to ensure the long-term viability of space exploration and settlement. This paper explores how AI-driven autonomous robots are being developed at the German Research Center for Artificial Intelligence and University of Bremen (Germany) to address these challenges.

Shea nut oil has been confirmed as a feasible and sustainable biofuel source and may be used to improve the economics of biodiesel production. However, there is need to evaluate the best route for achieving optimum yield and best quality. Therefore, two processes were investigated in this study - acid catalyzed and supercritical transesterification processes. Shea nut seeds were collected, its oil mechanically extracted thereafter, and the physiochemical properties were analyzed. In the acid catalysed process, shea nut oil was transesterified into biodiesel using ethanol with sulphuric acid (H2SO4) as a catalyst. This gave a conversion of between 55wt% and 90wt% for temperatures between 20oC and 90oC. The optimum ratio of ethanol/oil was found to be 30:1 at 80oC for reaction time of 120 minutes. While for supercritical transesterification process (without acid), the conversion was between 55wt% and 82.5wt% at temperatures between 220oC and 300oC. However, the optimum condition here was 20:1 ethanol/oil molar ratio, at 240oC and 24 minutes reaction time. The biodiesel properties produced were evaluated and most of these conformed to Biodiesel Standard, ASTM D- 6751 and the international standard, EN-14214. Also, the properties of Biodiesel produced by supercritical process seem better compared to that from the acid catalyzed process in line with the ASTM D – 6751 and EN-14214 standards, thus a better option for diesel engines making supercritical transesterification a preferred option for biodiesel production from shea nut oil.Keywords: Sheanut, biodiesel, transesterification, acid-catalysed, supercritical, conversion

Heat pump (HP) technology has been widely adopted in electric vehicles (EVs) for cabin and battery heating in cold weather due to its high efficiency. However, when an HP works under low ambient temperatures and high humidity, frost grows on the surface of the outdoor evaporator, deteriorating system efficiency. This study experimentally investigated the performance of an automotive reversible CO2 HP system under cyclic frosting–defrosting conditions, with different defrost-initiation criteria and orientations of the outdoor heat exchanger. The relationship between the performance degradation of the heat pump system and the feature of frost accumulation on the outdoor heat exchanger is analyzed. The experimental data revealed that the heating capacity of the HP system only mildly degrades (~30%), even with an air-side pressure drop of the outdoor heat exchanger growing 10 times, which enables the system to work in HP mode for a longer time before the defrosting without significantly impacting passengers’ comfort. The horizontally installed outdoor heat exchanger is proven to have better refrigerant distribution, but with approximately a 0.16 bar (11.9%) higher pressure drop, reducing the evaporating temperature by about 0.4 K. Consequently, frost accumulates faster, and the working time in HP mode is shortened by 12 min (18.2%). Moreover, the vertical outdoor heat exchanger drains much more water during the defrosting. As a result, the defrosting time for the vertical outdoor heat exchanger is reduced by 17%.

We compare the behavior of the finite-temperature Hartree-Fock model with that of thermal density functional theory using both ground-state and temperature-dependent approximate exchange functionals. The test system is bcc Li in the temperature-density regime of warm dense matter (WDM). In this exchange-only case, there are significant qualitative differences in results from the three approaches. Those differences may be important for Born-Oppenheimer molecular dynamics studies of WDM with ground-state approximate density functionals and thermal occupancies. Such calculations require reliable regularized potentials over a demanding range of temperatures and densities. By comparison of pseudopotential and all-electron results at ${\mathrm T} = 0$K for small Li clusters of local bcc symmetry and bond-lengths equivalent to high density bulk Li, we determine the density ranges for which standard projector augmented wave (PAW) and norm-conserving pseudopotentials are reliable. Then we construct and use all-electron PAW data sets with a small cutoff radius which are valid for lithium densities up to at least 80 g/cm$^3$.

In order to effectively y use the biomass resources for thermal applications, use of biomass pretreatment technologies like hydrothermal carb bonization are emerging. With the aim of studying the gasificcation performance of hydrothermal carbonized biomass ((biocoal) in high temperature air/steam medium, gasifica ation of two types of biocoal pellets produced from spentt grain and horse manure, was carried out in a fixed bed u updraft gasifier. Steam gasification gave syngas having 10­­11 MJ/Nm3 of LHV with both types of biocoal. The synga as yield and thus cold gas efficiency was higher with gasiffication of spent grain biocoal, but syngas purity in terms oof tar and particulates was better with gasification of horse e manure biocoal. Proceedings of the 22nd European Biomass Conference and Exhibition, 23-26 June 2014, Hamburg, Germany, pp. 626-631

Anthropogenic greenhouse gas emissions are triggering changes in global climate and warming the ocean. This will affect many marine organisms, particularly those with high site fidelity and habitat temperature preferences, such as humpback whales on their breeding grounds. To study the impacts of a warming ocean on marine organisms, large-scale projections of climatic variables are crucial. Global models are of 0.25 - 1° (~25-100 km) resolution, and not ideal to predict localized changes. Here, we provide 0.05° resolution (~5 km) sea surface temperature (SST) projections, statistically downscaled using the delta method. We illustrate the shifting isotherms of the critical 21 and 28°C boundaries, which border the climatic envelope that humpback whales prefer for their breeding grounds, over the course of the 21st century on a decadal temporal resolution. Results show by the end of the 21st century, 35% of humpback whale breeding areas will experience SSTs above or within 1°C of current thresholds if present-day social, economic, and technological trends continue (‘middle of the road’ CMIP6 greenhouse gas trajectory SSP2-RCP4.5). This number rises to 67% under the scenario describing rapid economic growth in carbon-intensive industries (‘fossil-fueled development’ CMIP6 greenhouse gas trajectory SSP5-RCP8.5). These projections highlight the importance of reducing global greenhouse gas emissions and minimizing further SST increases to preserve ecological integrity of humpback whale breeding areas. In this context, our results emphasize the need to focus on protection of critical ocean habitat and to provide high-resolution climate data for this purpose.