Search results for: exploration and production (E&P)

Authors: V. Reyes, P. Ferreira

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In response to high levels of competitiveness, industrial systems have evolved to improve productivity. As a consequence, a rapid increase in volume production and simultaneously, a customization process require lower costs, more variety, and accurate quality of products. Reducing time-cycle production, enabling customizability, and ensure continuous quality improvement are key features in advance intelligent industry. In this scenario, customers and producers will be able to participate in the ongoing production life cycle through real-time interaction. To achieve this vision, transparency, predictability, and adaptability are key features that provide the industrial systems the capability to adapt to customer demands modifying the manufacturing process through an autonomous response and acting preventively to avoid errors. The industrial system incorporates a diversified number of components that in advanced industry are expected to be decentralized, end to end communicating, and with the capability to make own decisions through feedback. The evolving process towards advanced intelligent industry defines a set of stages to empower components of intelligence and enhancing efficiency to achieve the decision-making stage. The integrated system follows an industrial cyber-physical system (CPS) architecture whose real-time integration, based on a set of enabler technologies, links the physical and virtual world generating the digital twin (DT). This instance allows incorporating sensor data from real to virtual world and the required transparency for real-time monitoring and control, contributing to address important features of the advanced intelligent industry and simultaneously improve sustainability. Assuming the industrial CPS as the core technology toward the latest advanced intelligent industry stage, this paper reviews and highlights the correlation and contributions of the enabler technologies for the operationalization of each stage in the path toward advanced intelligent industry. From this research, a real-time integration architecture for a cyber-physical system with applications to collaborative robotics is proposed. The required functionalities and issues to endow the industrial system of adaptability are identified.

Keywords: cyber-physical systems, digital twin, sensor data, system integration, virtual model

Procedia PDF Downloads 112

Authors: S. Lertsakulpasuk, S. Athichanagorn

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As depletion-drive gas reservoirs are abandoned when there is insufficient production rate due to pressure depletion, waterflooding has been proposed to increase the reservoir pressure in order to prolong gas production. Due to high cost, water injection may not be economically feasible. Water dumpflood into gas reservoirs is a new promising approach to increase gas recovery by maintaining reservoir pressure with much cheaper costs than conventional waterflooding. Thus, a simulation study of water dumpflood into multiple nearly abandoned or already abandoned thin-bedded gas reservoirs commonly found in the Gulf of Thailand was conducted to demonstrate the advantage of the proposed method and to determine the most suitable operational parameters for reservoirs having different system parameters. A reservoir simulation model consisting of several thin-layered depletion-drive gas reservoirs and an overlying aquifer was constructed in order to investigate the performance of the proposed method. Two producers were initially used to produce gas from the reservoirs. One of them was later converted to a dumpflood well after gas production rate started to decline due to continuous reduction in reservoir pressure. The dumpflood well was used to flow water from the aquifer to increase pressure of the gas reservoir in order to drive gas towards producer. Two main operational parameters which are wellhead pressure of producer and the time to start water dumpflood were investigated to optimize gas recovery for various systems having different gas reservoir dip angles, well spacings, aquifer sizes, and aquifer depths. This simulation study found that water dumpflood can increase gas recovery up to 12% of OGIP depending on operational conditions and system parameters. For the systems having a large aquifer and large distance between wells, it is best to start water dumpflood when the gas rate is still high since the long distance between the gas producer and dumpflood well helps delay water breakthrough at producer. As long as there is no early water breakthrough, the earlier the energy is supplied to the gas reservoirs, the better the gas recovery. On the other hand, for the systems having a small or moderate aquifer size and short distance between the two wells, performing water dumpflood when the rate is close to the economic rate is better because water is more likely to cause an early breakthrough when the distance is short. Water dumpflood into multiple nearly-depleted or depleted gas reservoirs is a novel study. The idea of using water dumpflood to increase gas recovery has been mentioned in the literature but has never been investigated. This detailed study will help a practicing engineer to understand the benefits of such method and can implement it with minimum cost and risk.

Keywords: dumpflood, increase gas recovery, low-pressure gas reservoir, multiple gas reservoirs

Procedia PDF Downloads 436

Authors: C. A. Roberts, S. L. Mascaro, J. R. Gerrish, J. L. Horner

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Management-intensive Grazing (MiG) is a practice that rotates livestock through paddocks in a way that best matches the nutrient requirements of the animal to the yield and quality of the pasture. In the USA, MiG has been taught to livestock producers throughout the state of Missouri in 2- and 3-day workshops called “Missouri Grazing Schools.” The economic impact of these schools was quantified using IMPLAN software. The model included hectares of adoption, animal performance, carrying capacity, and input costs. To date, MiG, as taught in the Missouri Grazing Schools, has been implemented on more than 70,000 hectares in Missouri. The economic impact of these schools is presently $125 million USD per year added to the state economy. This magnitude of impact is the result not only of widespread adoption but also because of increased livestock carrying capacity; in Missouri, a capacity increase of 25 to 30% has been well documented. Additional impacts have been MiG improving forage quality and reducing the cost of feed and fertilizer. The environmental impact of MiG in the state of Missouri is currently being estimated. Environmental impact takes into account the reduction in the application of commercial fertilizers; in MiG systems, nitrogen is supplied by N fixation from legumes, and much of the P and K is recycled naturally by well-distributed manure. The environmental impact also estimates carbon sequestration and methane production; MiG can increase carbon sequestration and reduce methane production in comparison to default grazing practices and feedlot operations in the USA.

Keywords: agricultural education, forage quality, management-intensive grazing, nutrient cycling, stock density, sustainable agriculture

Procedia PDF Downloads 194

Authors: Zebider Asire Munyelet, Yibeltal Chanie Manie

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In the modern digital landscape, the increase of social media platforms has become identical to the evolution of online consumer behavior. This study investigates the complicated relationship between social media and the purchasing decisions of online buyers. Through an extensive review of existing literature and empirical research, the aim is to comprehensively analyze the multidimensional impact that social media exerts on the various stages of the online buyer's journey. The investigation encompasses the exploration of how social media platforms serve as influential channels for information dissemination, product discovery, and consumer engagement. Additionally, the study investigates into the psychological aspects underlying the role of social media in shaping buyer preferences, perceptions, and trust in online transactions. The methodologies employed include both quantitative and qualitative analyses, incorporating surveys, interviews, and data analytics to derive meaningful insights. Statistical models are applied to distinguish patterns in online buyer behavior concerning product awareness, brand loyalty, and decision-making processes. The expected outcomes of this research contribute not only to the academic understanding of the dynamic interplay between social media and online buyer behavior but also offer practical implications for marketers, e-commerce platforms, and policymakers.

Keywords: consumer Behavior, social media, online purchasing, online transaction

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Authors: Djoudi Abdelhak, Djibaoui Rachid, Reguieg Yassaad Houcine

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Our study focuses on the identification of some species of Pseudomonas (P4, P5, P7 and P8) isolated from saline soils in northwestern Algeria and the effect of their metabolites on the growth of Alternaria alternata the causative agent of the blight of the bean disease (Vicia faba). We are also interested in stimulating the growth of this plant species in saline conditions (60 mM/l NaCl) and the absence of salts. The analysis focuses on rates of inhibition of mycelial growth of Alternaria alternata strain and the rate of growth of plants inoculated with strains of Pseudomonas expressed by biometrics. According to the results of the in-vitro test, P5 and P8 species and their metabolites showed a significant effect on mycelia growth and production of spores of Alternaria alternata. The in-vivo test shows that the species P8 and P5 were significantly and positively influencing the growth in biometric parameters of the bean in saline and salt-free condition. Inoculation with strain P5 has promoted the growth of the bean in stem height, stem fresh weight and dry weight of stems of 108.59%, 115.28%, 104.33%, respectively, in the presence of salt Inoculation with strain P5 has fostered the growth of the bean stem fresh weight of 112.47% in the presence of salt The effect of Pseudomonas species on the development of Vicia faba and the growth of Alternaria alternata is considering new techniques and methods of biological production and crop protection.

Keywords: pseudomonas, vicia faba, alternaria alternata, promoting of plant growth

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Authors: Soma Gholamveisy, Vahid Mirghavameddin

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Aquaculture activities face wide environmental, social, and economic problems today. To deal with these problems, the aquaculture business, which is already a highly significant agricultural activity, is influenced by sustainability, which can assure the rural community's safety and food health with minimal environmental damage. The objective of this study's systematic review of the literature (SLR) is to look into the use of global perspective Promotion of Sustainable Fisheries and Aquaculture. SLR aims to identify the goals of a promotional system, also one of its main components. This research seeks to empower, increase economic productivity, facilitate, pay more attention to the sustainability of the environment and inform the audience in this regard. A method used to assess hypotheses, condense the results of past studies or verify the consistency of studies. It presents a succinct analysis of original research using an unambiguous and verifiable approach. A thorough repository with a vast array of papers and effective exploration methods are frequently utilized in a systematic literature review, enabling the application of advanced logical statements. A comprehensive literature review was carried out to ensure that the most relevant studies were included. This type of review clarifies publication selection criteria and allows evaluation of the studies conducted and their repetition or extension.

Keywords: systematic review, sustainable, fisheries, aquaculture

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Authors: Li Chin Law, Epaminondas Mastorakos, Mohd Roslee Othman, Antonis Trakakis

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The paper introduces an alternative concept of carbon capture for shipping by using pre-combustion carbon capture technology (Pre-CCS), which was proven to be less energy intensive than post-combustion carbon capture from the engine exhaust. Energy assessment on amine-based post-combustion CCS on LNG-fuelled ships showed that the energy efficiency of CCS ships reduced from 48% to 36.6%. Then, an energy assessment was carried out to compare the power and heat requirements of the most used hydrogen production methods and carbon capture technologies. Steam methane reformer (SMR) was found to be 20% more energy efficient and achieved a higher methane conversion than auto thermal reaction and methane decomposition. Next, pressure swing adsorber (PSA) has shown a lower energy requirement than membrane separation, cryogenic separation, and amine absorption in pre-combustion carbon capture. Hence, an integrated system combining SMR and PSA (SMR-PSA) with waste heat integration (WHR) was proposed. This optimized SMR-based integrated system has achieved 65% of CO₂ reduction with less than 7-percentage point of energy penalty (41.7% of energy efficiency). Further integration of post-combustion CCS with the SMR-PSA integrated system improved carbon capture rate to 86.3% with 9-percentage points of energy penalty (39% energy efficiency). The proposed system was shown to be able to meet the carbon reduction targets set by International Maritime Organization (IMO) with certain energy penalties.

Keywords: shipping, decarbonisation, alternative fuels, low carbon, hydrogen, carbon capture

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Authors: Sanari Chalin Moriri, Kwabena Kingsley Ayisi, Alina Mofokeng

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Dryland smallholder farmers in South Africa are vulnerable to all kinds of risks, and it negatively affects crop productivity and profit. Pigeonpea is a leguminous and multipurpose crop that provides food, fodder, and wood for smallholder farmers. The majority of these farmers are still growing pigeonpea from traditional unimproved seeds, which comprise a mixture of genotypes. The objectives of the study were to identify the key risk factors that affect pigeonpea productivity and to develop management strategies on how to alleviate the risk factors in pigeonpea production. The study was conducted in two provinces (Limpopo and Mpumalanga) of South Africa in six municipalities during the 2020/2021 growing seasons. The non-probability sampling method using purposive and snowball sampling techniques were used to collect data from the farmers through a structured questionnaire. A total of 114 pigeonpea producers were interviewed individually using a questionnaire. Key stakeholders in each municipality were also identified, invited, and interviewed to verify the information given by farmers. Data collected were subjected to SPSS statistical software 25 version. The findings of the study were that majority of farmers affected by risk factors were women, subsistence, and old farmers resulted in low food production. Drought, unavailability of improved pigeonpea seeds for planting, access to information, and processing equipment were found to be the main risk factors contributing to low crop productivity in farmer’s fields. Above 80% of farmers lack knowledge on the improvement of the crop and also on the processing techniques to secure high prices during the crop off-season. Market availability, pricing, and incidence of pests and diseases were found to be minor risk factors which were triggered by the major risk factors. The minor risk factors can be corrected only if the major risk factors are first given the necessary attention. About 10% of the farmers found to use the crop as a mulch to reduce soil temperatures and to improve soil fertility. The study revealed that most of the farmers were unaware of its utilisation as fodder, much, medicinal, nitrogen fixation, and many more. The risk of frequent drought in dry areas of South Africa where farmers solely depend on rainfall poses a serious threat to crop productivity. The majority of these risk factors are caused by climate change due to unrealistic, low rainfall with extreme temperatures poses a threat to food security, water, and the environment. The use of drought-tolerant, multipurpose legume crops such as pigeonpea, access to new information, provision of processing equipment, and support from all stakeholders will help in addressing food security for smallholder farmers. Policies should be revisited to address the prevailing risk factors faced by farmers and involve them in addressing the risk factors. Awareness should be prioritized in promoting the crop to improve its production and commercialization in the dryland farming system of South Africa.

Keywords: management strategies, pigeonpea, risk factors, smallholder farmers

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Authors: Bidya Dhar Sahu, Meghana Koneru, R. Shyam Sunder, Ramakrishna Sistla

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Environmental and occupational exposure to hexavalent chromium [Cr(VI)] via textile manufacture, metallurgy, spray paints, stainless steel industries, drinking water containing chromium are often known to cause acute renal injury in humans and animals. Nephrotoxicity is the major effect of chromium poisoning. In the present study, we investigated the potential renoprotective effect and underlying mechanisms of carvedilol using rat model of potassium dichromate (K2Cr2O7)-induced nephrotoxicity. Exploration of the underlying mechanisms of carvedilol revealed that carvedilol attenuated nuclear translocation and DNA binding activity of NF-κB (p65), restored antioxidant and mitochondrial respiratory enzyme activities and attenuated apoptosis related protein expressions in kidney tissues. The serum levels of TNF-α, the renal iNOS and myeloperoxidase activity were significantly decreased in carvedilol pre-treated K2Cr2O7-induced nephrotoxic rats. These results were further supported and confirmed by histological findings. In conclusion, the findings of the present study demonstrated that carvedilol is an effective chemoprotectant against K2Cr2O7-induced nephrotoxicity in rats.

Keywords: apoptosis, carvedilol, inflammation, potassium dichromate-induced nephrotoxicity, applied pharmacology

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Authors: Yaw Akoto

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The social construction of disability in a Ghanaian society has created a restriction on the development of the academic potentials of persons with disabilities. Ghanaian societal perceptions position persons with disabilities as needy, evil, feeble and 'abnormal' that a person with disability cannot contribute anything meaningful to their own development, society, and the nation as well. Almost all Ghanaian cultures believe the Gods visit evil people with disability as such they erect barriers that limit them to select and enroll in education. The few people with disabilities who gain admission to schools drop out due to these barriers erected by the society and institutions. However, there are very few of these students who are able to pursue their education at the higher education level despite these challenges. This qualitative study explores the motivation of students with disabilities to select and enroll in a Ghanaian university. The study used semi-structured interview to solicit information from students with disabilities in a Ghanaian university. Although the quality of students with disabilities experience was affected by culture, discrimination, marginalisation, and lack of support, the prospect of using themselves as role models, employment opportunities and family impingement were among others that pushed them to embark on their educational journey. The findings of this study have implications for societal and institutional levels for restructuring and refining societal perception and institutional policies on disabilities.

Keywords: beliefs, Ghanaian university, social construction, students with disabilities

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Authors: Coriolano Salvini

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The increasing utilization of renewable energy sources for electric power production calls for the introduction of energy storage systems to match the electric demand along the time. Although many countries are pursuing as a final goal a “decarbonized” electrical system, in the next decades the traditional fossil fuel fed power plant still will play a relevant role in fulfilling the electric demand. Presently, such plants provide grid ancillary services (frequency control, grid balance, reserve, etc.) by adapting the output power to the grid requirements. An interesting option is represented by the possibility to use traditional plants to improve the grid storage capabilities. The present paper is addressed to small-medium size systems suited for distributed energy storage. The proposed Energy Storage System (ESS) is based on a Compressed Air Energy Storage (CAES) integrated into a Gas-Steam Combined Cycle (GSCC) or a Gas Turbine based CHP plants. The systems can be incorporated in an ex novo built plant or added to an already existing one. To avoid any geological restriction related to the availability of natural compressed air reservoirs, artificial storage is addressed. During the charging phase, electric power is absorbed from the grid by an electric driven intercooled/aftercooled compressor. In the course of the discharge phase, the compressed stored air is sent to a heat transfer device fed by hot gas taken upstream the Heat Recovery Steam Generator (HRSG) and subsequently expanded for power production. To maximize the output power, a staged reheated expansion process is adopted. The specific power production related to the kilogram per second of exhaust gas used to heat the stored air is two/three times larger than that achieved if the gas were used to produce steam in the HRSG. As a result, a relevant power augmentation is attained with respect to normal GSCC plant operations without additional use of fuel. Therefore, the excess of output power can be considered “fuel free” and the storage system can be compared to “pure” ESSs such as electrochemical, pumped hydro or adiabatic CAES. Representative cases featured by different power absorption, production capability, and storage capacity have been taken into consideration. For each case, a technical optimization aimed at maximizing the storage efficiency has been carried out. On the basis of the resulting storage pressure and volume, number of compression and expansion stages, air heater arrangement and process quantities found for each case, a cost estimation of the storage systems has been performed. Storage efficiencies from 0.6 to 0.7 have been assessed. Capital costs in the range of 400-800 €/kW and 500-1000 €/kWh have been estimated. Such figures are similar or lower to those featuring alternative storage technologies.

Keywords: artificial air storage reservoir, compressed air energy storage (CAES), gas steam combined cycle (GSCC), techno-economic analysis

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Authors: Hamitri-Guerfi Fatiha, Mekimene Lekhder, Madani Khodir, Youyou Ahcene

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Virgin olive oil is appreciated by consumers, the quality of the oil is regulated by the international olive oil council depends on its chemical composition, so, the correct packing conditions are a prerequisite to preserve oil color, flavor, and nutriments, from production to consumption. The contact of food with various materials of packaging, since the production, until their consumption constitutes one of the essential aspects of food safety (directive 76/833/CEE). In Algeria, plastic bottles, although, they are economic and light are largely used at packaging olive oil but not used in other countries. This is due to migration phenomena that can occur from these materials. Thus, the goal of this work is to examine the physicochemical behavior of the couple packaging plastic-oil during their exposure to three temperatures corresponding to the conditions of storage applied in Algeria. Like, it is difficult to compare blowers of bottles which are heavy engineering, it comes out from this study that the effect of heat, the absorption of water, the constraints of storage of acidity, as well as the composition of oil, the PET bottles showed a remarkable structural instability, this defect of quality was confirmed by the analysis of morphology by electronic scan microscopy. These bottles present a total migration significantly higher than the threshold of acceptance. Moreover, a metal contamination of oil by its packaging was confirmed by the spectroscopy of atomic absorption and a microanalysis. The differences observed between the results of the microanalysis applied and the mechanical characterizations of the various bottles are reported, showing the reality of the container-contents exchanges.

Keywords: interaction, stability, pet, virgin olive oil

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Authors: Amal Alatar

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The paper focuses on the exploration of architectural characteristics and decorative elements of the temple of Echmun, emphasizing the socio-economic significance of Sidon during the Greek and Roman periods to understand the implications of their spread and development on the Phoenician cities, as well as reveal the symbolical and societal connotations that may have been connected with the buildings, in order to allow a well-founded examination of common characteristics. In general, studying Phoenician archaeology posed some problems. The main problem is that most major Phoenician settlements lay beneath modern urban centers. This situation often prevented or largely restricted full archaeological investigations; the publications are frequently not complete enough to determine the basic characteristics of the architectural elements. Another key problem is the political instability of the region, which affected the archaeological research in the Phoenician homeland for many years. Nevertheless, during the past decades, an ever-growing cache of data was acquired from the archaeological surroundings of the Phoenician sites. Both the architectural elements from the Greek and Roman period have never been studied as a group before. Surprisingly, they have been largely ignored, despite their apparent profusion throughout the cities. The Roman period of Sidon has generally been neglected in preference to earlier periods, where it is often difficult to distinguish between Roman, Bronze age, medieval and Ottoman structures.

Keywords: archaeology, classical, Hellenistic, Eshmun Temple, architecture, Sidon, Lebanon

Procedia PDF Downloads 93

Authors: Nur A. Özdemir, Sude Erkin, Hatice K. Güney, Cemre S. Atılgan, Enes Huylu, Hüseyin Y. Altıntaş, Aysemin Top, Özak Durmuş

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Carbon emissions produced during a product’s life cycle, from extraction of raw materials up to waste disposal and market consumption activities are the major contributors to global warming. In the light of the science-based targets (SBT) leading the way to a zero-carbon economy for sustainable growth of the companies, carbon footprint reporting of the purchased goods has become critical for identifying hotspots and best practices for emission reduction opportunities. In line with Ford Otosan's corporate sustainability strategy, research was conducted to evaluate the carbon footprint of purchased products in accordance with Scope 3 of the Greenhouse Gas Protocol (GHG). The purpose of this paper is to develop a systematic and transparent methodology to calculate carbon footprint of the products produced by automotive OEMs (Original Equipment Manufacturers) within the context of automobile supply chain management. To begin with, primary material data were collected through IMDS (International Material Database System) corresponds to company’s three distinct types of vehicles including Light Commercial Vehicle (Courier), Medium Commercial Vehicle (Transit and Transit Custom), Heavy Commercial Vehicle (F-MAX). Obtained material data was classified as metals, plastics, liquids, electronics, and others to get insights about the overall material distribution of produced vehicles and matched to the SimaPro Ecoinvent 3 database which is one of the most extent versions for modelling material data related to the product life cycle. Product life cycle analysis was calculated within the framework of ISO 14040 – 14044 standards by addressing the requirements and procedures. A comprehensive literature review and cooperation with suppliers were undertaken to identify the production methods of parts used in vehicles and to find out the amount of scrap generated during part production. Cumulative weight and material information with related production process belonging the components were listed by multiplying with current sales figures. The results of the study show a key modelling on carbon footprint of products and processes based on a scientific approach to drive sustainable growth by setting straightforward, science-based emission reduction targets. Hence, this study targets to identify the hotspots and correspondingly provide broad ideas about our understanding of how to integrate carbon footprint estimates into our company's supply chain management by defining convenient actions in line with climate science. According to emission values arising from the production phase including raw material extraction and material processing for Ford OTOSAN vehicles subjected in this study, GHG emissions from the production of metals used for HCV, MCV and LCV account for more than half of the carbon footprint of the vehicle's production. Correspondingly, aluminum and steel have the largest share among all material types and achieving carbon neutrality in the steel and aluminum industry is of great significance to the world, which will also present an immense impact on the automobile industry. Strategic product sustainability plan which includes the use of secondary materials, conversion to green energy and low-energy process design is required to reduce emissions of steel, aluminum, and plastics due to the projected increase in total volume by 2030.

Keywords: automotive, carbon footprint, IMDS, scope 3, SimaPro, sustainability

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Authors: Nazim Habibov, Alena Auchynnikava, Lida Fan

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The exploration of the relationship between social trust and the support of the welfare system in transitional countries has attracted growing interests in recent decades. This study estimates the effects of interpersonal and institutional trust on the support of the welfare system in 27 countries in Eastern Europe the former Soviet Union. We estimate the data sets from the Life-in-Transition Survey 2010 and 2016 with binomial regression models. The results indicate that both interpersonal and institutional trust have positive effects on the support for the welfare system in all the three areas under investigation: helping the needy, public healthcare and public education, both in the less developed countries of the former Soviet Union and in the more developed Eastern European countries. Furthermore, the positive effects of interpersonal and institutional trust on support for helping the needy, public healthcare and public education were found to grow over time. In conclusion, this study confirms that interpersonal and institutional trusts have positive effects for the public support of the welfare system in these transitional countries under investigation, regardless of their level of development.

Keywords: central and eastern Europe, former Soviet union, international social welfare policy, comparative social welfare policy

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Authors: Sibele A. F. Leite, Bernno S. Leite, José Vicente H. D´Angelo, Ana Teresa P. Dell’Isola, Julio CéSar Souza

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The generation of bioenergy is one of the oldest and simplest biomass applications and is one of the safest options for minimizing emissions of greenhouse gasses and replace the use of fossil fuels. In addition, the increasing development of technologies for energy biomass conversion parallel to the advancement of research in biotechnology and engineering has enabled new opportunities for exploitation of biomass. Agricultural residues offer great potential for energy use, and Brazil is in a prominent position in the production and export of agricultural products such as banana and rice. Despite the economic importance of the growth prospects of these activities and the increasing of the agricultural waste, they are rarely explored for energy and production of new materials. Brazil products almost 10.5 million tons/year of rice husk and 26.8 million tons/year of banana stem. Thereby, the aim of this study was to analysis the potential of biomass residues for energy production and applications in new materials. Rice husk (specify the type) and banana stem (specify the type) were characterized by physicochemical analyses using the following parameters: organic carbon, nitrogen (NTK), proximate analyses, FT-IR spectroscopy, thermogravimetric analyses (TG), calorific values and silica content. Rice husk and banana stem presented attractive superior calorific (from 11.5 to 13.7MJ/kg), and they may be compared to vegetal coal (21.25 MJ/kg). These results are due to the high organic matter content. According to the proximate analysis, biomass has high carbon content (fixed and volatile) and low moisture and ash content. In addition, data obtained by Walkley–Black method point out that most of the carbon present in the rice husk (50.5 wt%) and in banana stalk (35.5 wt%) should be understood as organic carbon (readily oxidizable). Organic matter was also detected by Kjeldahl method which gives the values of nitrogen (especially on the organic form) for both residues: 3.8 and 4.7 g/kg of rice husk and banana stem respectively. TG and DSC analyses support the previous results, as they can provide information about the thermal stability of the samples allowing a correlation between thermal behavior and chemical composition. According to the thermogravimetric curves, there were two main stages of mass-losses. The first and smaller one occurred below 100 °C, which was suitable for water losses and the second event occurred between 200 and 500 °C which indicates decomposition of the organic matter. At this broad peak, the main loss was between 250-350 °C, and it is because of sugar decomposition (components readily oxidizable). Above 350 °C, mass loss of the biomass may be associated with lignin decomposition. Spectroscopic characterization just provided qualitative information about the organic matter, but spectra have shown absorption bands around 1030 cm-1 which may be identified as species containing silicon. This result is expected for the rice husk and deserves further investigation to the stalk of banana, as it can bring a different perspective for this biomass residue.

Keywords: rice husk, banana stem, bioenergy, renewable feedstock

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Authors: Tang Wei, Yang Xiaofeng, Gui Yewei, Du Yanxia

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Complex lifting entry was selected for precise landing performance during the Mars Science Laboratory entry. This study aims to develop the three-dimensional numerical method for precise computation and the surface panel method for rapid engineering prediction. Detailed flow field analysis for Mars exploration mission was performed by carrying on a series of fully three-dimensional Navier-Stokes computations. The static aerodynamic performance was then discussed, including the surface pressure, lift and drag coefficient, lift-to-drag ratio with the numerical and engineering method. Computation results shown that the shock layer is thin because of lower effective specific heat ratio, and that calculated results from both methods agree well with each other, and is consistent with the reference data. Aerodynamic performance analysis shows that CG location determines trim characteristics and pitch stability, and certain radially and axially shift of the CG location can alter the capsule lifting entry performance, which is of vital significance for the aerodynamic configuration des0ign and inner instrument layout of the Mars entry capsule.

Keywords: Mars entry capsule, static aerodynamics, computational fluid dynamics, hypersonic

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Authors: Adilla Anggraeni

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The purpose of the paper is to investigate the effects of religiosity and subjective knowledge towards initial trust that a consumer has towards a product manufacturer. Since globalization enters the point of no return, it should be acknowledged that further exploration of country of origin image, its influences and possible limiting factors is imperative. This model aims to broaden COO-related research, especially related to different product categories based on the perception of consumers in emerging markets. The study employs quantitative method, aiming to involve 200 Indonesian respondents to evaluate different product categories (food/apparel). Relationships between variables are evaluated using structural equation modeling. It is expected that subjective knowledge will have significant influence towards initial trust that an individual possesses towards food products. A major contribution of this study will be the inclusion of religiosity and subjective knowledge in the country of origin study’s body of knowledge. Companies are also expected to benefit from the study as the acceleration of globalization may again repose the question of whether companies should market their product using similar strategies across different countries or different ones. Religiosity dimension is expected to add values to international marketing literature concerning emerging economies in particular, as many companies view the emerging economies as promising markets.

Keywords: country of origin, subjective knowledge, initial trust, emerging economy, Indonesia

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Authors: Hamada Ahmed, Mervat A. Abdel-Latif, Alaa. A. Ghoraba, Samah A. Ganna

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An experiment was conducted to determine the effect of microbial phytase (Quantum Blue®) supplementation on layer chickens fed diets with required or low phosphorous level in corn-soybean based diets. One hundred and sixteen 23-week-old Lohman brown laying hens were used in 8-week feeding trial. Hens were randomly allotted into four treatments where the group (1) (control group) was fed basal diet without phytase, group (2) fed basal diet supplemented with phytase, group (3) fed diet supplemented with phytase as a replacement of 25% of monocalcium phosphate and group (4) fed diet supplemented with phytase as a replacement of 50% of monocalcium phosphate. Records on daily egg production, egg mass, egg weight and body weight of hens at the end of experimental period were recorded. Results revealed no significant (p ≥ 0.05) differences were observed among the other dietary treatments in BW, egg production, egg mass, feed intake or feed conversion when these parameters were evaluated over the duration of the experiment while egg weight showed significant (p < 0.05) increase in all phytase supplemented groups. There was no significant (p ≥ 0.05) differences in egg quality including egg length, egg width, egg shape index, yolk height, yolk width, yolk index, yolk weight and yolk albumin ratio while egg albumin was significantly increased (p < 0.05) in group (2) and group (3). Egg shell weight increased significantly (p < 0.05) in all phytase supplemented groups when compared with the control group also shell thickness increased significantly (p < 0.05) in both group (2 &3). No significant (P ≥ 0.05) difference was observed in serum Ca, P level while alkaline phosphatase was significantly (P ˂ 0.05) increased in group (3). Egg shell analysis showed increase in egg shell ash% in all phytase supplemented groups when compared with the control group, egg shell calcium % was higher in group (3) and group (4) than the control group while group (2) showed lower egg shell calcium% than the other experimental groups, egg shell phosphorous% was higher in all phytase supplemented groups than the control group. Phosphorous digestability was significantly (P ˂ 0.05) increased in all phytase supplemented groups than the control group and the highest p digestability was in group (4). Calcium digestability showed significant (P ˂ 0.05) increase in all phytase supplemented groups when compared with the control group and the highest digetability was in group (4).

Keywords: layers, microbial phytase, Ca and P availability, egg production, egg characteristics

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Authors: A. Douka, S. Vouyiouka, L. M. Papaspyridi, D. Korres, C. Papaspyrides

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A "green" process was studied for the preparation of partially renewable aliphatic polyesters based on 1,4-butanediol and 1,8-octanediol with various diacids and derivatives, namely diethyl succinate, adipic acid, sebacic acid, 1,12-dodecanedioic acid and 1,14-tetradecanedioic acid. A first step of enzymatic prepolymerization was carried out in the presence of two different solvents, toluene and diphenylether, applying molecular sieves and vacuum, respectively, to remove polycondensation by-products. Poly(octylene adipate) (PE 8.6), poly(octylene dodecanate)(PE 8.12) and poly(octylene tetradecanate) (PE 8.14) were firstly enzymatically produced in toluene using molecular sieves giving however, low-molecular-weight products. Thereafter, the synthesis of PE 8.12 and PE 8.14 was examined under optimized conditions using diphenylether as solvent and a more vigorous by-product removal step, such as application of vacuum. Apart from these polyesters, the optimized process was also implemented for the production of another long-chain polyester-poly(octylene sebacate) (PE 8.10) and a short-chain polyester-poly(butylene succinate) (PE 4.4). Subsequently, bulk post-polymerization in the melt or solid state was performed. SSP runs involved absence of biocatalyst and reaction temperatures (T) in the vicinity of the prepolymer melting point (Tm-T varied between 15.5 up to 4oC). Focusing on PE 4.4 and PE 8.12, SSP took place under vacuum or flowing nitrogen leading to increase of the molecular weight and improvement of the end product physical appearance and thermal properties.

Keywords: aliphatic polyester, enzymatic polymerization, solid state polymerization, Novozym 435

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Authors: Abbaas I. Kareem, H. Nikraz

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The use of recycled concrete aggregates (RCAs) in hot-mix asphalt (HMA) production could ease natural aggregate shortage and maintain sustainability in modern societies. However, it was the attached cement mortar and other impurities that make the RCAs behave differently than high-quality aggregates. Therefore, different upgrading treatments were suggested to enhance its properties before being used in HMA production. Disappointedly, some of these treatments had caused degradation to some RCA properties. In order to avoid degradation, a coating technique is developed. This technique is based on combining of two main treatments, so it is named as double coating technique (DCT). Dosages of 0%, 20%, 40% and 60% uncoated RCA, RCA coated with Cement Slag Paste (CSP), and Double Coated Recycled Concrete Aggregates (DCRCAs) in place of granite aggregates were evaluated. The results indicated that the DCT improves strength and reduces water absorption of the DCRCAs compared with uncoated RCAs and RCA coated with CSP. In addition, the DCRCA asphalt mixtures exhibit stability values higher than those obtained for mixes made with granite aggregates, uncoated RCAs and RCAs coated with CSP. Also, the DCRCA asphalt mixtures require less bitumen to achieve the optimum bitumen content (OBC) than those manufactured with uncoated RCA and RCA-coated with CSP. Although the results obtained were encouraging, more testing is required in order to examine the effect of the DCT on performance properties of DCRCA- asphalt mixtures such as rutting and fatigue.

Keywords: aggregate crashed value, double coating technique, hot mix asphalt, Marshall parameters, recycled concrete aggregates

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Authors: Ariadne Katsouras, Andrea Chareunsy

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The number of large hydroelectric dams in the world has increased from almost 6,000 in the 1950s to over 45,000 in 2000. Dams are often built to increase the economic development of a country. This can occur in several ways. Large dams take many years to build so the construction process employs many people for a long time and that increased production and income can flow on into other sectors of the economy. Additionally, the provision of electricity can help raise people’s living standards and if the electricity is sold to another country then the money can be used to provide other public goods for the residents of the country that own the dam. Dams are also built to control flooding and provide irrigation water. Most dams are of these types. This paper will give an overview of the environmental and economic theories of the impact of dams in different regions of the world. There is a difference in the degree of environmental and economic impacts due to the varying climates and varying social and political factors of the regions. Production of greenhouse gases from the dam’s reservoir, for instance, tends to be higher in tropical areas as opposed to Nordic environments. However, there are also common impacts due to construction of the dam itself, such as, flooding of land for the creation of the reservoir and displacement of local populations. Economically, the local population tends to benefit least from the construction of the dam. Additionally, if a foreign company owns the dam or the government subsidises the cost of electricity to businesses, then the funds from electricity production do not benefit the residents of the country the dam is built in. So, in the end, the dams can benefit a country economically, but the varying factors related to its construction and how these are dealt with, determine the level of benefit, if any, of the dam. Some of the theories or practices used to evaluate the potential value of a dam include cost-benefit analysis, environmental impacts assessments and regressions. Systems analysis is also a useful method. While these theories have value, there are also possible shortcomings. Cost-benefit analysis converts all the costs and benefits to dollar values, which can be problematic. Environmental impact assessments, likewise, can be incomplete, especially if the assessment does not include feedback effects, that is, they only consider the initial impact. Finally, regression analysis is dependent on the available data and again would not necessarily include feedbacks. Systems analysis is a method that can allow more complex modelling of the environment and the economic system. It would allow a clearer picture to emerge of the impacts and can include a long time frame.

Keywords: comparison, economics, environment, hydroelectric dams

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Authors: Maria Antonieta Erna Castillo Holly

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During the last decade, data analysis, strategic decision making, and the use of artificial intelligence (AI) tools in Latin American agriculture have been a challenge. In some countries, the availability, quality, and reliability of historical data, in addition to the current data recording methodology in the field, makes it difficult to use information systems, complete data analysis, and their support for making the right strategic decisions. This is something essential in Agriculture 4.0. where the increase in the global demand for fresh agricultural products of tropical origin, during all the seasons of the year requires a change in the production model and greater agility in the responses to the consumer market demands of quality, quantity, traceability, and sustainability –that means extensive data-. Having quality information available and updated in real-time on what, how much, how, when, where, at what cost, and the compliance with production quality standards represents the greatest challenge for sustainable and profitable agriculture in the region. The objective of this work is to present a methodological proposal for the collection of georeferenced data from the protected agriculture sector, specifically in production units (UP) with tall structures (Greenhouses), initially for Venezuela, taking the state of Mérida as the geographical framework, and horticultural products as target crops. The document presents some background information and explains the methodology and tools used in the 3 phases of the work: diagnosis, data collection, and analysis. As a result, an evaluation of the process is carried out, relevant data and dashboards are displayed, and the first satellite maps integrated with layers of information in a geographic information system are presented. Finally, some improvement proposals and tentatively recommended applications are added to the process, understanding that their objective is to provide better qualified and traceable georeferenced data for subsequent analysis of the information and more agile and accurate strategic decision making. One of the main points of this study is the lack of quality data treatment in the Latin America area and especially in the Caribbean basin, being one of the most important points how to manage the lack of complete official data. The methodology has been tested with horticultural products, but it can be extended to other tropical crops.

Keywords: greenhouses, protected agriculture, data analysis, geographic information systems, Venezuela

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Authors: Hugo Daneluzzo, Christelle Rabbat, Alan Jean-Marie

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Water electrolysis is one of the most advanced technologies for producing hydrogen and can be easily combined with electricity from different sources. Under the influence of electric current, water molecules can be split into oxygen and hydrogen. The production of hydrogen by water electrolysis favors the integration of renewable energy sources into the energy mix by compensating for their intermittence through the storage of the energy produced when production exceeds demand and its release during off-peak production periods. Among the various electrolysis technologies, anion exchange membrane (AEM) electrolyser cells are emerging as a reliable technology for water electrolysis. Modeling and simulation are effective tools to save time, money, and effort during the optimization of operating conditions and the investigation of the design. The modeling and simulation become even more important when dealing with multiphysics dynamic systems. One of those systems is the AEM electrolysis cell involving complex physico-chemical reactions. Once developed, models may be utilized to comprehend the mechanisms to control and detect flaws in the systems. Several modeling methods have been initiated by scientists. These methods can be separated into two main approaches, namely equation-based modeling and graph-based modeling. The former approach is less user-friendly and difficult to update as it is based on ordinary or partial differential equations to represent the systems. However, the latter approach is more user-friendly and allows a clear representation of physical phenomena. In this case, the system is depicted by connecting subsystems, so-called blocks, through ports based on their physical interactions, hence being suitable for multiphysics systems. Among the graphical modelling methods, the bond graph is receiving increasing attention as being domain-independent and relying on the energy exchange between the components of the system. At present, few studies have investigated the modelling of AEM systems. A mathematical model and a bond graph model were used in previous studies to model the electrolysis cell performance. In this study, experimental data from literature were simulated using OpenModelica using bond graphs and mathematical approaches. The polarization curves at different operating conditions obtained by both approaches were compared with experimental ones. It was stated that both models predicted satisfactorily the polarization curves with error margins lower than 2% for equation-based models and lower than 5% for the bond graph model. The activation polarization of hydrogen evolution reactions (HER) and oxygen evolution reactions (OER) were behind the voltage loss in the AEM electrolyzer, whereas ion conduction through the membrane resulted in the ohmic loss. Therefore, highly active electro-catalysts are required for both HER and OER while high-conductivity AEMs are needed for effectively lowering the ohmic losses. The bond graph simulation of the polarisation curve for operating conditions at various temperatures has illustrated that voltage increases with temperature owing to the technology of the membrane. Simulation of the polarisation curve can be tested virtually, hence resulting in reduced cost and time involved due to experimental testing and improved design optimization. Further improvements can be made by implementing the bond graph model in a real power-to-gas-to-power scenario.

Keywords: hydrogen production, anion-exchange membrane, electrolyzer, mathematical modeling, multiphysics modeling

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Authors: Razieh Karimi Aghcheh, Christian Kubicek, Joseph Strauss, Gerhard Braus

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Filamentous fungi are of considerable economic and social significance for human health, nutrition and in white biotechnology. These organisms are dominant producers of a range of primary metabolites such as citric acid, microbial lipids (biodiesel) and higher unsaturated fatty acids (HUFAs). In particular, they produce also important but structurally complex secondary metabolites with enormous therapeutic applications in pharmaceutical industry, for example: cephalosporin, penicillin, taxol, zeranol and ergot alkaloids. Several fungal secondary metabolites, which are significantly relevant to human health do not only include antibiotics, but also e.g. lovastatin, a well-known antihypercholesterolemic agent produced by Aspergillus. terreus, or aflatoxin, a carcinogen produced by A. flavus. In addition to their roles for human health and agriculture, some fungi are industrially and commercially important: Species of the ascomycete genus Hypocrea spp. (teleomorph of Trichoderma) have been demonstrated as efficient producer of highly active cellulolytic enzymes. This trait makes them effective in disrupting and depolymerization of lignocellulosic materials and thus applicable tools in number of biotechnological areas as diverse as clothes-washing detergent, animal feed, and pulp and fuel productions. Fungal LaeA/LAE1 (Loss of aflR Expression A) homologs their gene products act at the interphase between secondary metabolisms, cellulase production and development. Lack of the corresponding genes results in significant physiological changes including loss of secondary metabolite and lignocellulose degrading enzymes production. At the molecular level, the encoded proteins are presumably methyltransferases or demethylases which act directly or indirectly at heterochromatin and interact with velvet domain proteins. Velvet proteins bind to DNA and affect expression of secondary metabolites (SMs) genes and cellulases. The dynamic interplay between LaeA/LAE1, velvet proteins and additional interaction partners is the key for an understanding of the coordination of metabolic and morphological functions of fungi and is required for a biotechnological control of the formation of desired bioactive products. Aspergilli and Trichoderma represent different biotechnologically significant species with significant differences in the LaeA/LAE1-Velvet protein machinery and their target proteins. We, therefore, performed a comparative study of the interaction partners of this machinery and the dynamics of the various protein-protein interactions using our robust proteomic and mass spectrometry techniques. This enhances our knowledge about the fungal coordination of secondary metabolism, cellulase production and development and thereby will certainly improve recombinant fungal strain construction for the production of industrial secondary metabolite or lignocellulose hydrolytic enzymes.

Keywords: cellulases, LaeA/1, proteomics, secondary metabolites

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Authors: Bagnoud-Velásquez Mariluz, Damergi Eya, Grandjean Dominique, Frédéric Vogel, Ludwig Christian

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The sustainability of algae to biofuel processes is seriously affected by the energy intensive production of fertilizers. Large amounts of nitrogen and phosphorus are required for a large-scale production resulting in many cases in a negative impact of the limited mineral resources. In order to meet the algal bioenergy opportunity it appears crucial the promotion of processes applying a nutrient recovery and/or making use of renewable sources including waste. Hydrothermal (HT) conversion is a promising and suitable technology for microalgae to generate biofuels. Besides the fact that water is used as a “green” reactant and solvent and that no biomass drying is required, the technology offers a great potential for nutrient recycling. This study evaluated the possibility to treat the water HT effluent by the growth of microalgae while producing renewable algal biomass. As already demonstrated in previous works by the authors, the HT aqueous product besides having N, P and other important nutrients, presents a small fraction of organic compounds rarely studied. Therefore, extracted heteroaromatic compounds in the HT effluent were the target of the present research; they were profiled using GC-MS and LC-MS-MS. The results indicate the presence of cyclic amides, piperazinediones, amines and their derivatives. The most prominent nitrogenous organic compounds (NOC’s) in the extracts were carefully examined by their effect on microalgae, namely 2-pyrrolidinone and β-phenylethylamine (β-PEA). These two substances were prepared at three different concentrations (10, 50 and 150 ppm). This toxicity bioassay used three different microalgae strains: Phaeodactylum tricornutum, Chlorella sorokiniana and Scenedesmus vacuolatus. The confirmed IC50 was for all cases ca. 75ppm. Experimental conditions were set up for the growth of microalgae in the aqueous phase by adjusting the nitrogen concentration (the key nutrient for algae) to fit that one established for a known commercial medium. The values of specific NOC’s were lowered at concentrations of 8.5 mg/L 2-pyrrolidinone; 1mg/L δ-valerolactam and 0.5 mg/L β-PEA. The growth with the diluted HT solution was kept constant with no inhibition evidence. An additional ongoing test is addressing the possibility to apply an integrated water cleanup step making use of the existent hydrothermal catalytic facility.

Keywords: hydrothermal process, microalgae, nitrogenous organic compounds, nutrient recovery, renewable biomass

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Authors: Gabriel Sanjo Aruwajoye, E. B. Gueguim Kana

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Agricultural residues present a low-cost feedstock for bioenergy production around the world. Cassava peels waste are rich in organic molecules that can be readily converted to value added products such as biomaterials and biofuels. However, due to the presence of high proportion of structural carbohydrates and lignin, the hydrolysis of this feedstock is imperative to achieve maximum substrate utilization and energy yield. This study model and optimises the release of Fermentable Sugar (FS) from cassava peels waste using the Response Surface Methodology. The investigated pretreatment input parameters consisted of soaking temperature (oC), soaking time (hours), autoclave duration (minutes), acid concentration (% v/v), substrate solid loading (% w/v) within the range of 30 to 70, 0 to 24, 5 to 20, 0 to 5 and 2 to 10 respectively. The Box-Behnken design was used to generate 46 experimental runs which were investigated for FS release. The obtained data were used to fit a quadratic model. A coefficient of determination of 0.87 and F value of 8.73 was obtained indicating the good fitness of the model. The predicted optimum pretreatment conditions were 69.62 oC soaking temperature, 2.57 hours soaking duration, 5 minutes autoclave duration, 3.68 % v/v HCl and 9.65 % w/v solid loading corresponding to FS yield of 91.83g/l (0.92 g/g cassava peels) thus 58% improvement on the non-optimised pretreatment. Our findings demonstrate an efficient pretreatment model for fermentable sugar release from cassava peels waste for various bioprocesses.

Keywords: feedstock pretreatment, cassava peels, fermentable sugar, response surface methodology

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Authors: Rubab Zafar Kahlon, Ibtisam Butt

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Forest resources are deteriorating and experiencing decline around the globe due to unsustainable use and over exploitation. The present study was an attempt to determine the relationship between human activities, forest resource utilization, extraction methods and practices of forest resource exploitation in the district Jhelum of Pakistan. For this purpose, primary sources of data were used which were collected from 8 villages through structured questionnaire and tabulated in Microsoft Excel 365 and SPSS 22 was used for multiple linear regression analysis. The results revealed that farming, wood cutting, animal husbandry and agro-forestry were the major occupations in the study area. Most commonly used resources included timber 26%, fuelwood 25% and fodder 19%. Methods used for resource extraction included gathering 49%, plucking 34% trapping 11% and cutting 6%. Population growth, increased demand of fuelwood and land conversion were the main reasons behind forest degradation. Results for multiple linear regression revealed that Forest based activities, sources of energy production, methods used for wood harvesting and resource extraction and use of fuelwood for energy production contributed significantly towards extensive forest resource exploitation with p value <0.5 within the study area. The study suggests that effective measures should be taken by forest department to control the unsustainable use of forest resources by stringent management interventions and awareness campaigns in Jhelum district.

Keywords: forest resource, biodiversity, expliotation, human activities

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Authors: Natan C. G. Silva, Carlos A. C. Girao Neto, Marcele M. S. Vasconcelos, Luciana R. B. Goncalves, Maria Valderez P. Rocha

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Galactooligosaccharides (GOS) are sugars with prebiotic function that can be synthesized chemically or enzymatically, and this last one can be promoted by the action of β-galactosidases. In addition to favoring the transgalactosylation reaction to form GOS, these enzymes can also catalyze the hydrolysis of lactose. A highly studied type of GOS is lactulose because it presents therapeutic properties and is a health promoter. Among the different raw materials that can be used to produce lactulose, whey stands out as the main by-product of cheese manufacturing, and its discarded is harmful to the environment due to the residual lactose present. Therefore, its use is a promising alternative to solve this environmental problem. Thus, lactose from whey is hydrolyzed into glucose and galactose by β-galactosidases. However, in order to favor the transgalactosylation reaction, the medium must contain fructose, due this sugar reacts with galactose to produce lactulose. Then, the glucose-isomerase enzyme can be used for this purpose, since it promotes the isomerization of glucose into fructose. In this scenario, the aim of the present work was first to develop β-galactosidase biocatalysts of Kluyveromyces lactis and to apply it in the integrated reactions of hydrolysis, isomerization (with the glucose-isomerase from Streptomyces murinus) and transgalactosylation reaction, using whey as a substrate. The immobilization of β-galactosidase in chitosan previously functionalized with 0.8% glutaraldehyde was evaluated using different enzymatic loads (2, 5, 7, 10, and 12 mg/g). Subsequently, the hydrolysis and transgalactosylation reactions were studied and conducted at 50°C, 120 RPM for 20 minutes. In parallel, the isomerization of glucose into fructose was evaluated under conditions of 70°C, 750 RPM for 90 min. After, the integration of the three processes for the production of lactulose was investigated. Among the evaluated loads, 7 mg/g was chosen because the best activity of the derivative (44.3 U/g) was obtained, being this parameter determinant for the reaction stages. The other parameters of immobilization yield (87.58%) and recovered activity (46.47%) were also satisfactory compared to the other conditions. Regarding the integrated process, 94.96% of lactose was converted, achieving 37.56 g/L and 37.97 g/L of glucose and galactose, respectively. In the isomerization step, conversion of 38.40% of glucose was observed, obtaining a concentration of 12.47 g/L fructose. In the transgalactosylation reaction was produced 13.15 g/L lactulose after 5 min. However, in the integrated process, there was no formation of lactulose, but it was produced other GOS at the same time. The high galactose concentration in the medium probably favored the reaction of synthesis of these other GOS. Therefore, the integrated process proved feasible for possible production of prebiotics. In addition, this process can be economically viable due to the use of an industrial residue as a substrate, but it is necessary a more detailed investigation of the transgalactosilation reaction.

Keywords: beta-galactosidase, glucose-isomerase, galactooligosaccharides, lactulose, whey

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Authors: Husham Mahmood Ahmed

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For so many reasons, fresh water scarcity is one of major problems facing the world and in particularly in the third world in the Northern Africa, the Middle East, the Southwest of Asia, and many other desert areas. Solar distillation offers one of the most promising solutions of renewable energy to this aggravated situation. The main obstacle hindering the spread of the use of solar technology for fresh water production is its low efficiency. Therefore, enhancing the solar stills performances by studying the parameters affecting their productivity and implementing new ideas and a different design are the main goals of the investigators in recent years. The present research is experimental work that tests a new design of solar still with a hemispherical top cover for water desalination with and without external reflectors under the climate of the Kingdom of Bahrain during the autumn season. The hemispherical cover has a base diameter of 1m and a depth of 0.4m, die cast from a 6 mm thick Lexan plastic sheet. The net effective area was 0.785 m2. It has been found that the average daily production rate obtained from the hemispherical top cover solar still is 3.610 liter/day. This yield is 11.1% higher than the yield of a conventional simple type single slope solar still having 20ᴼ slope glass cover and a larger effective area of 1 m2 obtained in previous research under similar climatic conditions. It has also been found that adding 1.2m long by 0.15 curved reflectors increased the yield of the hemispherical solar still by 5.5 %, while the 1.2 long by 0.3m curved reflector increased the yield by about 8%.

Keywords: hemispherical solar still, solar desalination, solar energy, the Northern Africa

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