Economic potential of renewable energy sources use in Yemen

The article represents the evaluation of opportunities of economical potential use of renewed energy sources (solar, wind, hydro resources, tidal and thermal energy of the seas, biomass, high and low potential energy of geothermal) based on climatic data of Yemen. Technical and economic data on various device are generalized. Lacks and problems are indicated, the basic strategy priorities of power branch development of the country are defined. Favorable climatic conditions allow to speak about high technical and economic potential of renewed energy sources, and also about the high social importance of their use development

ELABORATION OF TASK CONTROL ALGORITHMS WITH PARALLEL COMPUTING IN CLUSTER COMPUTING SYSTEMS

The optimum problem of the allocation of tasks for executing in the cluster is considered. Task control algorithms are elaborated. The algorithms validation is done in the performance of the transportation problem on the local network cluster. The data obtained permit to judge efficiency of the suggested algorithms

Biodiesel production from microalgae Spirulina maxima by two step process: optimization of process variable

Biodiesel from green energy source is gaining tremendous attention for ecofriendly and economically aspect. In this investigation, a two-step process was developed for the production of biodiesel from microalgae Spirulina maxima and determined best operating conditions for the steps. In the first stage, acid esterification was conducted to lessen acid value (AV) from 10.66 to 0.51 mgKOH/g of the feedstock and optimal conditions for maximum esterified oil yielding were found at molar ratio 12: 1, temperature 60 degrees C, 1% (wt%) H2SO4, and mixing intensity 400 rpm for a reaction time of 90 min. The second stage alkali transesterification was carried out for maximum biodiesel yielding (86.1%) and optimal conditions were found at molar ratio 9: 1, temperature 65 degrees C, mixing intensity 600 rpm, catalyst concentration 0.75% (wt%) KOH for a reaction time of 20 min. Biodiesel were analyzed according to ASTM standards and results were within standards limit. Results will helpful to produce third generation algal biodiesel from microalgae Spirulina maxima in an efficient manner. (C) 2017 The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V

New records and addition to the flora of Saudi Arabia, mainly from Faifa Governorate, Jazan Region

Based on vegetation surveys made in the southern region of Saudi Arabia between 2020 and 2021, five new plant taxa including four species and one subspecies, belonging to four families that had not previously been recorded in Saudi Arabia's flora were discovered. Within the Arabian Peninsula, all newly recorded species (i.e., Alysicarpus vaginalis (L.) DC. (Fabaceae), Commiphora schimperi (O.Berg) Engl. (Burseraceae), Maerua angolensis DC. subsp. angolensis (Capparaceae), Peperomia leptostachya Hook. & Arn. (Piperaceae), and Vigna vexillata (L.) A.Rich. (Fabaceae) were recorded in Yemen while A. vaginalis was also recorded in Oman. Brief descriptions and comments on the phytogeography of each taxon are given. The distribution of plants in Faifa Mountains and surrounding areas was mapped using geographic information systems (GIS) and ground surveys

Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant's operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes