International Journal of Alternative Fuels and Energy 2017-12-14T18:17:38+00:00 International Journal of Alternative Fuels and Energy Open Journal Systems <p style="text-align: justify;">International Journal of Alternative Fuels and Energy (IJAFE; ISSN: 2523-9171)&nbsp; is a peer-reviewed, open access,&nbsp; international journal that considers articles on all aspects of alternative energy sources and allied sciences.</p> Finite Element Analysis of Seepage and Exit Gradient through a Non-Homogeneous Earth Dam without Filter Drain 2017-12-07T06:47:14+00:00 Imran Arshad Muhammed Muneer Babar <p>In this study, a slavе program of Gеo-Slopе softwarе (SЕЕP/W) was usеd to analyzе thе bеhavior of phrеatic linе along with thе computation of sееpagе flux and еxit gradiеnt for a non-homogеnous еarth dam (Hub dam) for two diffеrеnt casеs, with filtеr drain and without filtеr drain rеspеctivеly. Thе mеshеs were composеd of triangular, squarе, rеctangular and trapеzoidal typе of еlеmеnts. Thе mеsh for casе filter drain comprisеd of 2,297 nodеs, and 2,206 еlеmеnts, whilе for non-filter drain, 2,283 nodеs, and 2,198 еlеmеnts wеrе usеd. Thе simulation rеsults rеvеalеd that thе safеty of thе Hub dam, at its original dеsign, is not еndangеrеd from the sееpagе point of viеw as thе prеsеncе of filtеr drain has a dirеct еffеct on rеducing positivе porе watеr prеssurе within thе dam. Duе to low positivе porе watеr prеssurе within thе dam for filter drain, thе phrеatic linе was falling into thе filtеr drain aftеr passing thе corе with an ovеrall minimum sееpagе flux of 2.113 x 10<sup>-4</sup>&nbsp;ft<sup>3</sup>/sеc/ft and еxit gradiеnt at downstrеam toе 0.099 rеspеctivеly. Howеvеr, whеn thе modеl was run with samе gеomеtry and matеrial propеrtiеs without filtеr drain, a vеry high еxit gradiеnt was obsеrvеd for (normal and maximum pond lеvеl) scеnarios and thе bеhavior of phrеatic linе was also found abnormal as it cuts thе downstrеam slopе of thе dam. Though thе sееpagе flux was found (28 – 29%) lеss, but duе to the absence of frее passagе within thе dam for thе rеmoval of еxtra watеr, thе porе watеr prеssurе within thе dam еspеcially at downstrеam facе bеcomеs high and lеads to a slopе failurе. This impliеs that filtеr drain еspеcially in еarth dams plays a pivotal rolе to control thе phrеatic linе trеnd and еxit gradiеnt by rеducing thе positivе porе watеr prеssurе within thе dam body and to savе thе dam from downstrеam slopе failurе rеspеctivеly.</p> 2017-06-23T00:00:00+00:00 ##submission.copyrightStatement## Electricity Generation in Microbial Fuel Cells as a Function of Air: Cathode Configuration 2017-12-07T06:50:51+00:00 Blagovesta Midyurova Valentin Nenov <p>An inexpensive carbon black and Polytetrafluoroethylene (PTFE) air- cathode was developed as an alternative to an expensive metal catalyst and Nafion electrode for oxygen reduction in microbial fuel cell (MFC). The carbon black (Vulcan) was cold- pressed with PTFE binder to form the cathode around a steel mesh current collector. These constructions avoided the need for expensive metal catalyst and Nafion and produced a cathode with high current densities. Tests with three cathodes with different ratio of PTFE: Vulkan (5: 0.3; 0.2; 0.1g) produced a maximum current value as follows: 291 µA, 283 µA and 12 µA, respectively.&nbsp;<em>&nbsp;</em></p> 2017-08-31T00:00:00+00:00 ##submission.copyrightStatement## Biodiesel Production by Alkali Catalyzed Transesterification of chicken and beef fats 2017-12-13T19:38:29+00:00 Saher Ashraf Majid Hussain Muhammad Waseem Mumtaz Muhammad Shuaib <p>Biodiesel is renewable, biodegradable and environment friendly fuel. Actually biodiesel is mono alkyl esters of animal fats oil and vegetable oils. Biodiesel from animal fat oils produced through transesterification in presence of methanol and alkaline catalyst. In this study alkaline base catalyst KOH was used. The response surface methodology (RSM) was used to determine the optimum conditions for the production of biodiesel through alkaline-catalyzed transesterification of chicken and beef tellow. From the results of the present study the optimum reaction conditions for methanolysis of chicken and beef tallow i.e., 0.50% KOH as catalyst, methanol/ oil molar ratio 2.1:1, reaction temperature 60<sup>o</sup>C, rate of mixing 600 rpm and a reaction time of 60 min, provided 88% of biodiesel yield. The influence of the catalyst concentration was very important because at higher catalyst concentrations the % age yield of biodiesel was decreased and also if moisture content is greater in environment then conversion lead to the soap formation. The oil/methanol molar ratio was one of the variables that had the most prevalent influence on the transesterification process. Fuel properties were determined such as the flash, pour points of biodiesel produced are found to be somewhat higher, which may point to potential difficulties in cold starts. Thus, biodiesel derived from chicken and beef tallow is an acceptable substitute for petrodiesel. Physical and chemical analysis of biodiesel showed that it is more economical and contributes less to global warming as compared to fossil fuels burning. Biodiesel seems to be realistic fuel for future. It has become more attractive recently because of its environmental benefits.</p> 2017-12-07T00:00:00+00:00 ##submission.copyrightStatement## Recent Trends in Animal Fats and Oils to Biodiesel Research: Conversion Methods, Technical Challenges and Assessment of Economic and Environmental Impacts 2017-12-14T11:51:43+00:00 Muhammad Naeem Iqbal Asfa Ashraf <p>Changes in climate due to the enormous amount of carbon dioxide emissions have really encouraged the development of energy sources that are renewable, sustainable, and eco-friendly (Alajmi <em>et al.,</em> 2017). In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction especially alkali-catalyzed transesterification (Leung <em>et al.,</em> 2010). Triacylglycerols (fats and oils) are converted into esters by transesterification reaction producing three smaller molecules of ester and one molecule of glycerin from one molecule of fat or oil. Glycerin is removed as by-product and esters are known as biodiesel (Fazal <em>et al., </em>2011). Sustainable alternatives for biodiesel production are being researched with the use of enzymes; enzymatic transesterification has attracted much attention for biodiesel production as it produces high purity product and enables easy separation from the byproduct, glycerol. (Ranganathan <em>et al.,</em> 2008). The development of alternative energy sources can also be attributed to the rapid decrease in resources of fossil energy. Although, most studies regarding the use of animal wastes as feedstock in biodiesel production are still in the early stages and have not focus on the recent advances in the use of animal fats waste (Alajmi <em>et al.,</em> 2017).</p> <p>Biodiesel is attracting an increasing deal of attention worldwide for it is currently the only renewable energy carrier which could directly replace diesel fuel in compression ignition engines because of its positive cumulative energy values when compared to petroleum-derived diesel (Vonortas and Papayannakos, 2014). In their study, Tabatabaei et al. (2015) documented the recent innovations in biodiesel production which are presented under three categories of upstream, mainstream, and downstream processes.</p> <p>Among the many challenges yet to be overcome before one could portray biodiesel as a sustainable alternative for decades to come is an economic feedstock supply. In fact, it is now well-documented that the price of feedstock could account for 70-88% of the total biodiesel production cost and hence is considered as the most significant factor affecting the economic viability of the biodiesel market (Hasheminejad <em>et al.,</em> 2011). Non-edible feedstocks such as animal fat wastes (AFWs) have recently increased in popularity as alternatives to vegetable oils in the production of biodiesel. They are low cost, mitigate environmental damage and increase the quality of the resultant biodiesel fuel (low NOx emissions, high Cetane number and oxidative stability) (Adewale <em>et al.,</em> 2015). The main challenging issue is its high free fatty acid (FFA) content. In fact, it has been reported&nbsp; that&nbsp; biodiesel&nbsp; yield&nbsp; could&nbsp; drop&nbsp; down&nbsp; to&nbsp; 6%&nbsp; when&nbsp; the&nbsp; FFA&nbsp; content increases just above 5% wt. (Moser, 2011). The most current biodiesel synthesis processes cannot handle feedstock with high FFA content; it was proved that the supercritical fluid process can result in a significant advantage for feedstocks with any fatty acid content (Yang, 2004).</p> <p>An alternative fuel to petrodiesel must be technically feasible, economically competitive, environmentally acceptable and easy available (Demirbas, 2009). FAME from vegetable oils and animal fats have shown promise as biodiesel, due to improved viscosity, volatility and combustion behaviour relative to triacylglycerols, and can be used in conventional diesel engines without significant modifications (Bhatti <em>et al.,</em> 2008).</p> <p>The advantages of biodiesel over diesel fuel are its portability, ready availability, renewability, higher combustion efficiency, lower sulphur and aromatic content, higher cetane number, higher biodegradability, better emission profile, safer handling, besides being non-toxic (Lapuerta et al., 2008; Demirbas, 2009). Moreover, biodiesel offers advantages regarding the engine wear, cost, and availability. When burned, biodiesel produces pollutants that are less detrimental to human health (Fazal <em>et al.,</em> 2011).</p> <p>Usage of biodiesel will allow a balance to be sought between agriculture, economic development and environment (Demirbas, 2009). Lower cost feedstocks are needed since biodiesel from food-grade oils is not economically competitive with petroleum-based diesel fuel.</p> 2017-12-14T00:00:00+00:00 ##submission.copyrightStatement## Microbial Alginate Production: Does Nature of Alginate Relate to Source Microorganism 2017-12-14T18:17:38+00:00 Asfa Ashraf Fakhar-un-Nisa Yunus Muhammad Naeem Iqbal <p><strong>EDITORIAL</strong></p> <p>Alginate is formed of the mannuronate (M-block) and residues of guluronate (G-block) organized in intermittent blocks in linear chain. Currently, the source of alginate is the cell wall of the brown seaweeds (Saude and Junter, 2002), where they are found as mixed salts of Ca, Na and K with alginic acid (Clementi <em>et al., </em>1995). Alginate obtained from various algae sp. or among several sections in the same algae has different amount of these salts (Sabra, 1998). Alginate can be produced from the brown seaweeds and from bacteria (Donati and Paoletti, 2009).</p> <p>At present the giant brown kelp <em>M. pyrifera</em> is the origin for commercial production of alginate. As commercial production of alginate is limited to few species of brown algae regarding abundance, location and uniform quality, the search for alternative bacterial alginate is need of the hour. Some prokaryotic microbes of two genera like <em>Azotobacter</em> sp. (Gorin and Spencer, 1966) and <em>Pseudomonas</em> (Cote and Krull, 1988; Moral and Yildiz, 2016) have ability to produce alginate. The alginate produced by <em>Azotobacter vinelandii</em> has similar blocks of monomer residues to that of alginate produced by seaweeds (Steinbuchel <em>et al.,</em> 2001).</p> <p>Various bacterial species are capable to produce alginate and most important among them are <em>Pseudomonas </em>sp.&nbsp;and&nbsp;<em>Azotobacter </em>sp. Many studies on molecular mechanisms of alginate biosynthesis by bacteria have been done on <em>Pseudomonas aeruginosa</em>&nbsp;which is the opportunistic human pathogen and&nbsp;<em>Azotobacter </em>which is the soil dwelling bacteria. Even though these two bacteria (<em>Pseudomonas </em>and<em> Azotobacter</em>), secrete alginate in nature by using the same molecular mechanism. Both bacterial species <em>Azotobacter</em> and <em>Pseudomonas</em> synthesize the alginate in vegetatively growing cells as an extracellular polysaccharide (EPS) (Steinbuchel <em>et al.,</em> 2001). It has been documented that alginate obtained from <em>Pseudomonas</em> lack G blocks (Skjak-Braek <em>et al.,</em> 1986) whereas alginate obtained from <em>Azotobacter</em> may have these blocks. There are reports about the development of thick highly structured biofilms from alginate produced by mucoid strains of&nbsp;<em>P</em>.&nbsp;<em>aeruginosa</em> (Hay&nbsp;<em>et al</em>.,&nbsp;2009), whereas<em> Azotobacter </em>produce the stiffer alginate with usually a greater amounts of G residues. These G residues remains closely linked with the cell permitting the development of desiccation resistant cysts (Sabra and Zeng, 2009). The monomer composition and molecular weight of alginates are known to have effects on their properties (Urtuvia <em>et al.,</em> 2017).&nbsp;</p> <p>There have been investigations about biosynthesis of bacterial alginate, their potential uses in applications requiring distinct substantial possessions (Hay <em>et al.,</em> 2013). There are various characteristics including high molecular mass and the negative charge of bacterial alginate that confirm its hydrated and viscous nature. The broad distribution of <em>Azotobacter</em> and <em>Azospirillum</em> in various surroundings, such as water, soil and residues make it ecologically important. The broad metabolic diversity of <em>Azotobacter </em>spp.<em> and</em> <em>Azospirillum</em> spp. has made it capable of degrading different highly resistant substrates for increase in plant yield by increasing fixed nitrogen in the soil (Ashraf, 2016). There has been a partial association of alginate biosynthesis with the growth of bacteria.</p> 2017-12-14T00:00:00+00:00 ##submission.copyrightStatement##