Theoretical study of the structural stability, electronic and magnetic properties of XVSb (X == Fe, Ni, and Co) half-Heusler compounds

The structural, electronic and magnetic properties of half-Heusler compounds XVSb (X $=$ Fe, Co and Ni) are investigated by using the density functional theory with generalized gradient approximation (GGA), and Tran-Blaha modified Becke-Johnson (TB-mBJ) exchange potential approximation. It is found that the half-metallic gaps are generally reasonably widened by mBJ as compared to the GGA approximation. The magnetic proprieties of XVSb (X $=$ Fe, Co and Ni) are well defined within mBJ with an exact integer value of magnetic moment. The band gaps given by TB-mBJ are in good agreement with the available theoretical data. The FeVSb exhibits a semiconductor nature. The CoVSb and NiVSb present half-metallic behaviour with total magnetic moment of $1\mu_\text{B}$ and $2\mu_\text{B}$ in good agreement with Slater-Pauling rule. These alloys seem to be a potential candidate of spintronic devices.Comment: 9 pages, 5 figure

Electricity from Wood: A Wood Quality and Energy Efficiency Approach to Small Scale Pyro-gasification

AbstractThe global demand for renewable energy in the last years is facing innovations like the co-generation of electricity and heat from wooden industrial residues and biomass. Wood gasification is a very promising technique for conversion of wood chemical energy into thermal energy and into electricity. A new generation of small scale, moderately priced and easy to install pyro-gasification plants became available on the market, being an opportunity for the SMEs. These systems are also characterized by a remarkable operational easiness and great versatility in the type of used biomass, which can range from industrial residues (sawdust, wood chips...) to biomass of forestry and non-forestry origin. This study performed an extensive testing of a small size pyro-gasification plant capable of producing 30kW of electricity and 30kW of thermal energy, both net to enter in the network of GSE (Energy Services Manager) via the feed-in tariff and in a small district heating network or other uses. The process of pyro-gasification is analyzed in its entirety by a characterization of input biomass, pyro-gasification process monitoring, analysis of the quality of the produced syngas, characterization of residues due to the process (washing water smoke, charcoal...) and verification of the total efficiency. The electric efficiency of the system, from hardwood to syngas to electricity is quantified in being 12%

The assessment of hazelnut mechanical harvesting productivity

ArticleHazelnut cultivation represents a new opportunity for Calabrian mountainous and sloping areas (Southern Italy), where no alternative fruit crops, except forestry, could be settled. In this Region, hazelnut production doubled during the last fifty years, inciting the farmers to introduce mechanization in cropping practices such as harvesting in order to increase productivity and decrease production costs. Indeed, harvesting is currently one of the most expensive processes of the productive cycle, moreover to be time consuming if carried out manually. Mechanization degree depends significantly on the terrain topography: in sloping areas, rakes are often associated to aspirating machines to harvest the fallen fruit, while the employment of harvesting machines from the ground prevails in flat areas. In this context, the present paper aims to assess technical and economic aspects of harvesting operation, using a harvester from the ground model ‘Jolly 2800’ (GF s.r.l., Italy). Particularly, for technical purposes data about operational working time as well as working productivity were collected according to CIOSTA requirements, in two harvesting sites, whereas, for mechanical harvesting economic evaluation, an estimation model was applied to calculate machinery cost per hour. Moreover, the cost per kg of hazelnut in shell and the average cost per hectare were estimated also. The obtained results show a working productivity of 0.065 ha h-1 op-1 in the first harvesting site, while it was equal to 0.022 ha h -1 op-1 in the second one. Concerning the average cost per hectare, the second harvesting site showed the worst economic performances, with 550.76 € ha-1 against 182.54 € ha-1 obtained in the first one

Análise da experiência multidisciplinar na construção do livro 3d de embriologia humana

A abordagem do tema sobre o desenvolvimento humano requer uma maior abstração do estudante no que concerne a compreensão e visualização tridimensional dos diversos estágios embrionário e fetal. Isso requer a utilização de novos recursos didáticos ou ferramentas que os apoiem, principalmente as que não utilizem material humano. O objetivo deste trabalho é relatar a experiência na elaboração do Livro 3D de Embriologia Humana, um projeto multidisciplinar e apresentar o resultado final do projeto. A equipe foi composta por 9 professores e 15 alunos dos cursos de Medicina, Design, Sistemas de Informação, Letras e Comunicação Social do Centro Universitário de Volta Redonda-UniFOA. O conteúdo do livro foi discutido e escolhido para ser escrito pelos alunos do curso de Medicina. A revisão ortográfica e gramatical foi realizada pelos graduandos do curso de Letras. Após a finalização do conteúdo, os colaboradores do curso de Comunicação Social gravaram em estúdio a narração do livro que foi ilustrado pelos alunos dos cursos de Medicina e Design. Ficou sob responsabilidade dos colaboradores dos cursos de Design e Sistemas de Informação a construção do livro e dos objetos tridimensionais. Cada núcleo de alunos, por curso, tinha pelo menos um professor orientador dentro de sua área de conhecimento que revisava e supervisionava as etapas de realização. A maior dificuldade encontrada pela equipe foi a construção dos objetos 3D, que exigiu a interação constante dos alunos do curso de Medicina com os de Design para que as imagens fossem as mais próximas do real e tecnicamente corretas. Outra dificuldade superada pelo grupo foi a terminologia técnica utilizada pelos alunos de Medicina, revisada pelos alunos de Letras e narrados pela equipe de Comunicação Social. Um dos pontos positivos foi a multidisciplinaridade e a construção coletiva. Temas como semiótica e reforma ortográfica tiveram que ser debatidos entre os alunos e professores dos diferentes cursos, tornando o projeto um aprendizado ainda maior para o grupo

An automated medium scale prototype for anaerobic co-digestion of olive mill wastewater

Olive oil production constitutes one of the most important agro-industrial business for Mediterranean countries, where 97% of the international production is focused. Such an activity, mainly carried out through three phase olive oil mill plants, generates huge amounts of solid and liquid by-products further than olive oil. Physico-chemical features of these by-products depend on various factors such as soil and climatic conditions, agricultural practices and processing. As currently carried out, the disposal of these by-products may lead to numerous problems taking into account management, economic and particularly environmental aspects. Indeed, olive mill wastewater is not easily biodegradable due to its high chemical and biochemical oxygen demand, its high content in phenolic compounds, high ratio C/N and low pH, leading consequently to soil and water source pollution. Considering, the above-mentioned statements, olive mill waste disposal constitutes nowadays a challenge for oil industry stakeholders. It becomes necessary to look for alternative solutions in order to overcome environmental problems and ensure the sustainability of oil industry. Anaerobic co-digestion of olive mill wastewater with other agro-industrial matrices could be one of these solutions; since it offers the possibility to produce green energy and break down toxicological compounds contained in these wastewater for a better disposal of the digested matrices as soil conditioner. In this contest, this note reports the functioning principle of an automated medium scale plant for anaerobic co-digestion of olive mill wastewater. Keywords: Medium scale prototype, Olive mill wastewater (OMWW), Anaerobic co-digestion (AcoD), Automatic proces