Dynamic temperature model for proton exchange membrane fuel cell using online variations in load current and ambient temperature

This paper presents a dynamic temperature model for a proton exchange membrane fuel cell (PEMFC) system. The proposed model overcomes the complexity of conventional models using first-order expressions consisting of load current and ambient temperature. The proposed model also incorporates a PEMFC cooling system, which depends upon the temperature difference between events. A dynamic algorithm is developed to detect load changing events and calculate instantaneous PEMFC temperature variations. The parameters of the model are extracted by employing the lightning search algorithm (LSA). The temperature characteristics of the NEXA 1.2 kW PEMFC system are experimentally studied to validate model performance. The results show that the proposed model output and the temperature data obtained from experiments for linear and abrupt changes in PEMFC load current are in agreement. The root-mean-square error between the model output and experimental results is less than 0.9. Moreover, the proposed model outperforms the conventional models and provides advantages such as simplicity and adaptability for low and high sampling data rates of input variables, namely, load current and ambient temperature. The model is not only helpful for simulations but also suitable for dynamic real-time controllers and emulators.     

Ziziphus spina-christi leaf extract attenuates mercuric chloride-induced liver injury in male rats via inhibition of oxidative damage

Environmental Science and Pollution Research - Heavy metal contamination including mercury (Hg) has become one of the most serious environmental problems facing humans and other living organisms....     

Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models1

Robertson, Dale M. and David A. Saad, 2011. Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models. Journal of the American Water Resources Association (JAWRA) 47(5):1011‐1033. DOI: 10.1111/j.1752‐1688.2011.00574.x Abstract: Nutrient input to the Laurentian Great Lakes continues to cause problems with eutrophication. To reduce the extent and severity of these problems, target nutrient loads were established and Total Maximum Daily Loads are being developed for many tributaries. Without detailed loading information it is difficult to determine if the targets are being met and how to prioritize rehabilitation efforts. To help address these issues, SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed for estimating loads and sources of phosphorus (P) and nitrogen (N) from the United States (U.S.) portion of the Great Lakes, Upper Mississippi, Ohio, and Red River Basins. Results indicated that recent U.S. loadings to Lakes Michigan and Ontario are similar to those in the 1980s, whereas loadings to Lakes Superior, Huron, and Erie decreased. Highest loads were from tributaries with the largest watersheds, whereas highest yields were from areas with intense agriculture and large point sources of nutrients. Tributaries were ranked based on their relative loads and yields to each lake. Input from agricultural areas was a significant source of nutrients, contributing ～33‐44% of the P and ～33‐58% of the N, except for areas around Superior with little agriculture. Point sources were also significant, contributing ～14‐44% of the P and 13‐34% of the N. Watersheds around Lake Erie contributed nutrients at the highest rate (similar to intensively farmed areas in the Midwest) because they have the largest nutrient inputs and highest delivery ratio.     

Assessment of Groundwater Quality in a Structurally Deformed Granitic Terrain in Hyderabad, India

Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co, Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported by rainfall and groundwater flow.     

Approaches for prevention and environmental management of novel COVID-19

Environmental Science and Pollution Research - The World Health Organization (WHO) recognized a novel coronavirus as the causative agent of a new form of pneumonia. It was subsequently named...     

Scientific Bases for Pollution Control in African Inland Waters

The awareness of the harm caused by pollutants to natural environments has led the political and legislative authorities of industrially-developed countries to introduce or review regulations to protect the environment. However, in recent years, all over the world and particularly in many countries in Africa, there has been a remarkable population growth, accompanied by an intense urbanization, an increase of industrial activities and a higher exploitation of cultivable land. These transformations have brought about a huge increase in the quantity of discharges and a wide diversification in the types of pollutants that reach river waters and have undesirable effects on fish and on the potential for fishery exploitation.     

Integrating gender and environment in NGO training

The global concern for the survival of the planet earth draws particular attention to the Third World countries and the impact of degrading forces on sustainable development. A different response to the growing ecological crisis has recently come to the fore. This response comes from women engaged in the struggle for survival. Women in the Third World, because of their situation on the fringes of society and their role producing sustenance, are often able to offer ecological insights that are deeper and richer than the recipes of technocrats and international experts or ideas resulting from enquiries addressed only to the men in communities. In the following the author seeks to demonstrate how women often bear the brunt of suffering resulting from environmental degradation, wars and poverty that plague the Near East region. However, training of women, especially poor women, in environmental management, and the active participation of local women in community and regional decision making holds a clear promise of eventually controlling the vicious circle of poverty and environmental degradation. An intermediate step is the coordination of NGO activities in a common front for environmental protection and income generation for the poor. Further training of the NGO's own staff in the design and implementation of such projects is also required.     

Roadmap for carbon neutrality: the mediating role of clean energy development-related investments

Environmental Science and Pollution Research - Recently, the Japanese government has announced the national objective of turning the economy of Japan carbon–neutral by 2050. This...