An integrated model to evaluate water-energy-food nexus at a household scale

ArticleThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.To achieve a sustainable supply and effectively manage water, energy and food (WEF) demand, interactions between WEF need to be understood. This study developed an integrated model, capturing the interactions between WEF at end-use level at a household scale. The model is based on a survey of 419 households conducted to investigate WEF over winter and summer for the city of Duhok, Iraq. A bottom-up approach was used to develop this system dynamics-based model. The model estimates WEF demand and the generated organic waste and wastewater quantities. It also investigates the impact of change in user behaviour, diet, income, family size and climate. The simulation results show a good agreement with the historical data. Using the model, the impact of Global Scenario Group (GSG) scenarios was investigated. The results suggest that the ‘fortress world’ scenario (an authoritarian response to the threat of breakdown) had the highest impact on WEF.This work was financially supported by the Human Capacity Development Program in Higher Education (HCED) in Kurdistan, Iraq. We acknowledge the support for this work provided by Dr. Sarah Ward and Ziyad Ahmed

An atomic mechanism for the boson peak in metallic glasses

The boson peak in metallic glasses is modeled in terms of local structural shear rearrangements. Using Eshelby's solution of the corresponding elasticity theory problem (J. D. Eshelby, Proc. Roy. Soc. A241, 376 (1957)), one can calculate the saddle point energy of such a structural rearrangement. The neighbourhood of the saddle point gives rise to soft resonant vibrational modes. One can calculate their density, their kinetic energy, their fourth order potential term and their coupling to longitudinal and transverse sound waves.Comment: 9 pages, 7 figures, 31 references, contribution to 11th International Workshop on Complex Systems, Andalo (Italy), March 200

Life cycle assessment of a biogas system for cassava processing to close the loop in the water-waste-energy-food nexus in Brazil

Biogas, generated from anaerobic digester (AD), has been one of the promising sources of renewable energy. To manage the organic waste from small cassava industry in Brazil, a waste-water-energy-food nexus (WWEF) system is proposed, combining AD and co-generation or combined heat and power (CHP) plants. However, the environmental impacts and benefits of this system are yet not known. By using Life Cycle Assessment (LCA) method, environmental impacts of three scenarios are assessed, i.e. business-as-usual (base), improved business-as-usual and WWEF closed-loop. Functional unit (FU) in this study is defined as generating 1 kg cassava starch/flour. Global warming potential (GWP), cumulative energy demand (CED), freshwater eutrophication potential (FEP), terrestrial acidification potential (TAP) and water depletion potential (WDP) are selected. Landfilling cassava waste, power use for cassava starch and flour production, and emissions from fertilizer application are identified as environmental hotspots for business-as-usual case, suggesting making decisions on these aspects when dealing with environmental impacts. By using cassava waste to recover energy and nutrients for Brazilian rural family farming, the WWEF system is identified as the best environment-friendly scenario with lowest environmental impacts for the selected impact categories. The impact savings of the closed-loop scenario for GWP are over 90%, while over 50% of emissions for other selected impact categories, except FEP (lower than 10%), are saved compared to the business-as-usual and improved scenarios. Sensitivity analysis reinforces the results. Overall, this study provides a view on the potential of using cassava waste for the WWEF closed-loop system in Brazil, suggesting that the proposed WWEF closed-loop system is feasible and beneficial for small industries from the environmental perspective

Design of Electronic Learning Courses for IT Students Considering the Dominant Learning Style

Methods of using e-learning courses to support learning activities of students at higher educational institutions is the subject of a large number of scientific and educational studies. In particular, much attention is paid to the structure, content and format of educational resources of e-learning courses. However, the problem of dependency of their efficiency on the learning styles of students still needs to be further researched. This paper deals with the learning styles characteristic for IT students on the basis of determining their leading modality; designs the structure of e-learning courses for IT students considering the dominating learning styles and provides the results of pedagogical experiment by measuring the performance and satisfaction in learning activity

Evaluation of Rapid Methods in Malaria Diagnosis from Persons attending Primary Health Facilities, Ogun State, Nigeria

Malaria in Nigeria is treated blindly in most cases and where diagnostic measures exist, efficacies of several are still in doubt. This study evaluated performance of microscopy and rapid (RDT) methods in confirming prevalence of malaria parasites (MP),parasite species and percent parasitized red blood cells in 384 persons systematically selected from seven primary healthcare facilities in Ogun State, Nigeria from October to December 2012. Giemsa thin and thick film techniques and RDT (SD Bioline Ag P.f/Pan kit) were employed on the blood samples. Data were analysed using SPSS version 16. Demographic results showed that females were 61% and males 39%,but of varying age groups. Seventy-one percent of the blood samples were positive for MP by microscopic blood films, and only 24% samples were positive by RDT. Paired sample T-test showed a significant difference (P=0.000)between microscopy and RDT methods. Of the 273 positive blood samples,95.6%were P. falciparum,3.3% were P. malariae, 0.7% was P. ovale and P. vivax (0.4%). For RDT, P. falciparum was 74% while mixed infections were 26%. Prevalence in risk groups 0–10 and 11–20 age groups was observed to be higher with significant differences (p=0.011, p=0.023) for both microscopy and RDT respectively. RDT sensitivity and specificity were 23.4% and 74.7% compared to microscopy. Positive Predictive Value and Negative Predictive Value were 69.6% and 28.4%. The efficiency of the RDT was 38.3%. The low sensitivity of RDT observed means that malaria diagnosis by microscopy method remains the gold standar

Herd-level risk factors associated with Leptospira Hardjo seroprevalence in Beef/Suckler herds in the Republic of Ireland

<p>Abstract</p> <p>Background</p> <p>The aim of the present study was to investigate risk factors for herd seropositivity to <it>Leptospira </it>Hardjo in Irish suckler herds. Herds were considered eligible for the study if they were unvaccinated and contained ≥ 9 breeding animals of beef breed which were ≥ 12 months of age. The country was divided into six regions using county boundaries. Herd and individual animal prevalence data were available from the results of a concurrent seroprevalence study. Herds were classified as either "Free from Infection" or "Infected" based on a minimum expected 40% within-herd prevalence.</p> <p>Questionnaires were posted to 320 farmers chosen randomly from 6 regions, encompassing 25 counties, of the Republic of Ireland. The questionnaire was designed to obtain information about vaccination; reproductive disease; breeding herd details; the presence of recognized risk factors from previous studies; and husbandry on each farm. Data collected from 128 eligible herds were subjected to statistical analysis.</p> <p>Results</p> <p>Following the use of Pearson's Chi-Square Test, those variables associated with a herd being "infected" with a significance level of P < 0.2 were considered as candidates for multivariable logistic regression modelling. Breeding herd size was found to be a statistically significant risk factor after multivariable logistic regression. The odds of a herd being positive for leptospiral infection were 5.47 times higher (P = 0.032) in herds with 14 to 23 breeding animals compared with herds with ≤ 13 breeding animals, adjusting for Region, and 7.08 times higher (P = 0.033) in herds with 32.6 to 142 breeding animals.</p> <p>Conclusions</p> <p>Breeding herd size was identified as a significant risk factor for leptospiral infection in Irish suckler herds, which was similar to findings of previous studies of leptospirosis in dairy herds.</p