A real-time simulating non-isothermal mathematical model for the passive feed direct methanol fuel cell

In order to understand the complex transport phenomena in a passive direct methanol fuel cell (DMFC), a theoretical model is essential. The analytical model provides a computationally efficient framework with a clear physical meaning. For this, a non-isothermal, analytical model for the passive DMFC has been developed in this study. The model considers the coupled heat and mass transport along with electrochemical reactions. The model is successfully validated with the experimental data. The model accurately describes the various species transport phenomena including methanol crossover and water crossover, heat transport phenomena, and efficiencies related to the passive DMFC. It suggests that the maximum real efficiency can be achieved by running the cell at low methanol feed concentration and moderate current density. The model also accurately predicts the effect of various operating and geometrical parameters on the cell performance such as methanol feed concentration, surrounding temperature, and polymer electrolyte membrane thickness. The model predictions are in accordance with the findings of the other researchers. The model is rapidly implementable and can be used in real-time simulation and control of the passive DMFC. This comprehensive model can be used for diagnostic purpose as well.     

Photovoltaic-thermal (PV/t) panel to minimize electrical and air conditioning energy consumption of a typical office in Beirut

A combined photovoltaic–thermal (PV/t) panel is proposed to produce simultaneously electricity and heat from one integrated unit. The unit utilizes effectively the solar energy through achieving higher PV electrical efficiency and using the thermal energy for heating applications. To predict the performance of the PV/t at a given environmental conditions, a transient mathematical model was developed. The model was integrated in a heating application for a typical office space in the city of Beirut to provide the office needs for electricity, heating during winter season, and dehumidification and evaporative cooling during the summer season. To minimize the yearly office energy (electrical and heat) needs, the PV/t panel cooling air flow rate and the dehumidification regeneration temperature were determined for opimal unit operation. Thermal energy savings of up to 85% in winter and 71% in summer were achived compared to conventional systems at a payback period of 8 years for the panels.     

Linking landscape development intensity within watersheds to methyl-mercury accumulation in river sediments

An indicator of the disturbance of natural systems, the landscape development intensity (LDI) index, was used to assess the potential for land-use within watersheds to influence the production/accumulation of methyl-mercury (MeHg) in river sediments. Sediment samples were collected from locations impacted by well-identified land-use types within the Mobile-Alabama River Basin in Southeastern USA. The samples were analyzed for total-Hg (THg) and MeHg concentrations and the obtained values correlated to the calculated LDI indexes of the sampled watersheds to assess the impact of prevalent land use/land cover on MeHg accumulation in sediments. The results show that unlike THg, levels of MeHg found in sediments are impacted by the LDI indexes. Overall, certain combinations of land-use types within a given watershed appear to be more conducive to MeHg accumulation than others, therefore, pointing to the possibility of targeting land-use practices as potential means for reducing MeHg accumulation in sediments, and ultimately, fish contamination.     

Environment contamination by mycotoxins and their occurrence in food and feed: Physiological aspects and economical approach

The contamination of food and feed by mycotoxins as toxic metabolites of fungi is a risk not only for consumers resulting in various embarrassment regarding health status and well-being, but also for producers, companies and export market on the ground of economic losses and ruined stability of economic trade. As it is given in historical evidence, the contamination of food by mycotoxins is a topic as old as a history of mankind, finding some evidence even in the ancient books and records. Nowadays, the mycotoxins are used in modern biotechnological laboratories and are considered an agent for targeting the specific cells (e.g., defected cells to eliminate them). However, this promising procedure is only the beginning. More concern is focused on mycotoxins as abiotic hazard agents. The dealing with them, systematic monitoring, and development of techniques for their elimination from agricultural commodities are worldwide issues concerning all countries. They can be found alone or in co-occurrence with other mycotoxins. Thus, this review aims to provide widened information regarding mycotoxins contamination in environment with the consequences on health of animals and humans. The inevitability for more data that correctly determine the risk points linked to mycotoxins occurrence and their specific reactions in the environment is demonstrated. This review includes various symptoms in animals and humans that result from mycotoxin exposure. For better understanding of mycotoxin's impact on animals, the sensitivities of various animal species to various mycotoxins are listed. Strategies for elimination and preventing the risks of mycotoxins contamination as well as economical approach are discussed. To complete the topic, some data from past as historical evidences are presented.     

Power generation by high head water in a building using micro hydro turbine—a greener approach

Demand for green energy production is arising all over the world. A lot of emphasis is laid in making the buildings green. Even a small amount of energy savings made contribute to saving the environment. In this study, an idea is proposed and studied to extract power from the high head water in the pipelines of a building. A building of height 15 m is considered for this study. Water flowing in the pipe has sufficient energy to run a micro hydro turbine. The feasibility of producing electrical energy from the energy of pipe water is found. The motivation is to find the feasibility of generating power using a low-cost turbine. The experimental setup consists of micro turbine of 135 mm diameter coupled to a 12-V DC generator; LEDs and resistors are employed to validate the results. The theoretical calculations were presented using the fundamental equations of fluid mechanics. The theoretical results are validated using experimental and numerical results using CFD simulation. In addition, exergy analysis has been carried out to quantify the irreversibilities during the process in the system.     

Assessment of Presence of Heavy Metals and Other Pollution Burden Parameters and Their Effect on Water Quality in Benin City,Edo State

An assessment of the heavy metal content and biological pollution burden of an abattoir dumpsite, an automobile carwash, the Ikpoba River, and a private water borehole located near the abattoir dumpsite was conducted in Benin City in Southern Nigeria, during the rainy and dry seasons. The water samples’ pH was lower than the permissible values, with the river water displaying color and possessing a slight odor. Iron concentrations exceeded the permissible limits for drinking water at all four of the sampling stations in the study area, although not in samples collected from the control station, station 5, a public water borehole that is located some distance away. Lead values were higher than drinking water standards in the samples collected from stations 1 through 4, with some exceptions during the rainy season. Copper, nickel, arsenic, chromium, and aluminum were detected in three out of the four sampling stations located within the study area. However, these metals were detected at levels that were within regulatory limits. The detection of three metals (iron, lead, and zinc) within the study area at levels exceeding drinking water limits suggested that a complete cycle of movement of pollutants into the sampling stations had occurred. Significant biological presences were also detected, as the Ikpoba River water had a standard plate count (SPC) of 130 most probable number (MPN) and a 22 MPN presumptive coliform count (PCC) or 22 MPN. However, Escherichia coli (E. coli) confirmatory tests recorded less than 2 MPN in both seasons. The study has shown that the quality of water in the river may be compromised by effluent discharges from the dumpsite and the carwash channel. Therefore, this situation requires more stringent enforcement of local environmental laws and maintenance of safe distances between domestic and industrial waste sources and domestic or private water wells.     

Think Global,Buy National: CSR,Cooperatives and Consumer Concerns in the Norwegian Food Value Chain

In a world where issues of food safety and food security are increasingly important, the social responsibility of central actors in the food chain—producers and the main grocery chains—becomes more pressing. As a response, these actors move from implicitly assuming social responsibilities implied in laws, regulations and ethical customs, towards explicitly expressing social responsibilities. In this paper, we discuss the ethical values relevant for the social responsibility of central food producers and retailers in Norway, one of the most subsidized and protected areas of food production in the world. How do the actors perceive and express their social responsibility, and—given their position in the local, national and global market—how should they handle these responsibilities? We analyze Tine and Nortura, two producers owned by farmer cooperatives with market regulator function, as well as Coop—a dominant grocery chain in Norway, with basis in the same public ownership model as the farmer-owned cooperative producers. While the complex roles of these key actors in the Norwegian food market have been criticized from several angles, we argue that these multifaceted roles put them in a good position to promote informed consumer choices in a globalized market.