Identification and molecular characterization of Listeria monocytogenes isolated in raw milk in the region of Algiers (Algeria)

Listeria monocytogenes was isolated from raw milk, whey and curdled milk produced and collected in the region of Algiers and Blida between September 2003 and July 2004. Four out of 153 (2.61%) farm milk samples and 6 out of 80 (7.50%) tankers' samples tested positive for L. monocytogenes. All samples of whey and curdled milk (n=12) tested negative for L. monocytogenes, but 2 of 22 (9%) samples of whey were contaminated by L. innocua. L. monocytogenes isolates were grouped by a multiplex PCR assay; all isolates belonged to the PCR-group IVb, which corresponds to serovars 4b, 4d and 4e. L. monocytogenes isolates were characterized by Pulsed-Field Gel Electrophoresis (PFGE). The combination of AscI and ApaI macrorestriction patterns yielded five different pulsovars (I to V). The results indicate that raw milk, and raw milk products are potential sources of the L. monocytogenes and represent a potential risk for consumers.     

Utilization of pico hydro generation in domestic and commercial loads

Pico hydro is a term used to distinguish very small-scale hydropower with a maximum electrical output of five kilowatts (5 kW). It is a good technique of providing electricity to the off-grid remote and isolated regions that suffer energy deficit. Typical pico hydro generator is designed and supported by electrical converting system, batteries and safety equipment so that it can be installed at the residential water pipeline. In pico hydro generation, the environmental impact is negligible since large dams are not involved, and the schemes can be managed and maintained by the consumer. This paper is reviewing the application of hydro generation and particularly focusing on the implementation of pico hydro generation system in University Malaysia Pahang (UMP) Campus-Pekan. This system was designed and simulated using the Matalb simulink blocks. The pico hydro generator has been tested in a real application with a pelton turbine design which utilizes a high pressure of water flowing from the main tank into the faculties. The speed of the turbine and alternator depend on the pressure of the water. In this work, a 1.05 kW alternator is used to charge the battery and the DC power output from a battery is converted into 220 V, 50 Hz.     

Fuzzy-modeling with Particle Swarm Optimization for enhancing the production of biodiesel from Microalga

Biodiesel is one of the promising energy sources that could replace petroleum oil in the near future. Microalgae is occupying a distinguished position among the promising sources for biodiesel production. Enhancement of the lipids production during the pretreatment is a key factor for the biodiesel production. High-pressure homogenizer is a better pretreatment procedure to enhance the lipid extraction from microalgae. In this research, a robust model of biodiesel system using fuzzy logic is built based on the experimental data for biodiesel system. Then, Particle Swarm Optimization (PSO) optimizer is applied for determining the best operating parameters of biodiesel system. The decision variables used in the optimization process are; pressure, number of passes, and reaction time that maximizes the percentage of recovery lipids of biodiesel. A comparison study was carried out between the optimized results thought PSO algorithm and those obtained by the experimental results and the optimized results through the Response Surface Methodology (RMS). Results demonstrated that using the proposed optimization methodology is significantly better than RSM, a nearly 78.7% increase in lipids extraction could be achieved according to the current model.     

Hydrogen production from organic fatty acids using carbon-doped TiO2 nanoparticles under visible light irradiation

The photocatalytic production of H₂ using carbon-doped TiO₂ (CTiO₂) nanoparticles has been investigated in single or mixed systems of organic fatty acids (OFAs) under visible light irradiation, including acetic acid, propionate acid, butyric acid and lactic acid. When OFAs were applied at the same electron density (10 e-eq L^?1), the H₂ evolution rates followed the order of propionic acid > butyric acid ≈ acetic acid > lactic acid, whereas at the same molar concentration (0.5 mol L^?1), that order changed to lactic acid > acetic acid > butyric acid ≈ propionic acid. This result implied that the electron transfer efficiency differed from four OFAs, probably due to their different affinity with CTiO₂. O₂^?? and CH₃? partially contributed to OFAs degradation and H₂ production. The quantum dynamics simulations of electron transfer revealed that the dominant mechanism of H₂ production was direct electron transfer from adsorbed OFAs to CTiO₂. This work aims to pursue the synergy of solar energy utilization and conversion of OFAs into H₂.     

Transition metal nanoparticles doped carbon paper as a cost-effective anode in a microbial fuel cell powered by pure and mixed biocatalyst cultures

The poor wettability and high cost of the carbonaceous electrodes materials prohibited the practical applications of microbial fuel cells (MFCs) on large scale. Here, a novel nanoparticles of metal sheathed with metal oxide is electrodeposited on carbon paper (CP) to introduce as high-performance anodes of microbial fuel cell (MFC). This thin layer of metal/metal oxide significantly enhance the microbial adhesion, the wettability of the anode surface and decrease the electron transfer resistance. The investigation of the modified CP anodes in an air-cathode MFCs fed by various biocatalyst cultures shows a significant improving in the MFC performance. Where, the generated power and current density was 140% and 210% higher as compared to the pristine CP. Mixed culture of exoelectrogenic microorganism in wastewater exhibited good performance and generated higher power and current density compared to yeast as pure culture. The excellent capacitance with a distinctive nanostructure morphology of the modified-CP open an avenues for practical applications of MFCs.     

Electrophoretic deposition of graphene oxide on carbon brush as bioanode for microbial fuel cell operated with real wastewater

Microbial fuel cell (MFC) is a promising technology for simultaneous wastewater treatment and energy harvesting. The properties of the anode material play a critical role in the performance of the MFC. In this study, graphene oxide was prepared by a modified hummer's method. A thin layer of graphene oxide was incorporated on the carbon brush using an electrophoretic technique. The deoxygenated graphene oxide formed on the surface of the carbon brush (RGO-CB) was investigated as a bio-anode in MFC operated with real wastewater. The performance of the MFC using the RGO-CB was compared with that using plain carbon brush anode (PCB). Results showed that electrophoretic deposition of graphene oxide on the surface of carbon brush significantly enhanced the performance of the MFC, where the power density increased more than 10 times (from 33 mWm^?2 to 381 mWm^?2). Although the COD removal was nearly similar for the two MFCs, i.e., with PCB and RGO-CB; the columbic efficiency significantly increased in the case of RGO-CB anode. The improved performance in the case of the modified electrode was related to the role of the graphene in improving the electron transfer from the microorganism to the anode surface, as confirmed from the electrochemical impedance spectroscopy measurements.     

Integrated standalone hybrid solar PV,fuel cell and diesel generator power system for battery or supercapacitor storage systems in Khorfakkan,United Arab Emirates

Renewable energy resources play a very important rule these days to assist the conventional energy systems for doing its function in the UAE due to high greenhouse gas (GHG) emissions and energy demand. In this paper, the analysis and performance of integrated standalone hybrid solar PV, fuel cell and diesel generator power system with battery energy storage system (BESS) or supercapacitor energy storage system (SCESS) in Khorfakkan city, Sharjah were presented. HOMER Pro software was used to model and simulate the hybrid energy system (HES) based on the daily energy consumption for Khorfakkan city. The simulation results show that using SCESS as an energy storage system will help the performance of HES based on the Levelized cost of energy (LCOE) and greenhouse gas (GHG) emissions. The HES with SCESS has renewable fraction (68.1%) and 0.346 $/kWh LCOE. The HES meets the annual AC primary load of the city (13.6 GWh) with negligible electricity excess and with an unmet electrical load of 1.38%. The reduction in GHG emissions for HES with SCESS was 83.2%, equivalent to saving 814,428 gallons of diesel.     

Application of backward differentiation methods to the finite element solution of time-dependent problems

The application of finite element methods to parabolic partial differential equations leads to large linear systems of first-order ordinary differential equations. Very often these systems are stiff and difficulties arise in their numerical solution. We attempt to analyse the problem of how to select numerical methods for the solution of such linear systems.     

Mitigation of Major Peanut Allergens by Pulsed Ultraviolet Light

Peanut allergy represents one of the most severe IgE-mediated reactions with food, but to date, the only effective way to prevent peanut allergy is total avoidance. If allergens could be mitigated during food processing before a product reaches the consumer, this would substantially lessen the food allergy problem. The efficacy of pulsed ultraviolet light (PUV), a novel food processing technology, on reducing peanut allergens, was examined. This study revealed for the first time that PUV was also capable of deactivating Ara h 2, the most potent allergenic protein of peanut. Protein extracts from raw and roasted peanuts were treated for 2, 4, and 6?min and peanut butter slurry was treated for 1, 2, and 3?min in a Xenon Steripulse XL 3000? PUV system. The distance from the central axis of the lamp was varied at 10.8, 14.6, and 18.2?cm. The SDS?CPAGE showed a reduction in the protein band intensity for Ara h 1, Ara h 2, and Ara h 3 at the energy levels ranging from 111.6 to 223.2?J/cm². Reduction of the protein band intensity for peanut allergens increased with treatment time but decreased with increased distance from the PUV lamp. The ELISA for peanut extracts and peanut butter slurry showed a reduction in IgE binding of up to 12.9- and 6.7-folds, respectively, compared to control.