Performance Improvement of Air-cooled Battery Thermal Management System using Sink of Different Pin-Fin Shapes

One of the most important influences on battery safety, capacity, and cell ageing is heat generation and temperature inhomogeneity, which cause unbalanced ageing, resulting in cell performance decline. A well-developed temperature management module is required to avoid such undesirable actions. In this study, an air-cooled temperature management module was developed by coupling a unique heat sink of different pin-fin geometries/shapes to prismatic Li-ion cells and a 3D transient analysis was conducted to simulate the cooling performance of this heat sink under the effect of inlet airflow velocities and temperatures at a discharge rate of 2C for three cases. The results in the form of maximum temperature and temperature homogeneity inside the battery were derived and compared to the commonly used circular pin-fin heat sink. The overall result indicates that case 2, which consists of uniform height, shows better promise than others, taking into consideration the geometry employed. After 600 s and at a constant inlet air velocity of 0.412 m/s across a range of 20 oC to 35 oC, it was found that this heat sink performed better, providing an average of 1.87% and 1.93% improvement in temperature homogeneity and battery maximum temperature, respectively. Also, at a constant inlet air temperature of 27 oC across the range of inlet air velocity of 0.206 m/s to 0.824 m/s, this heat sink provides an average of 1.77% and 0.27% improvement in temperature homogeneity and battery maximum temperature, respectively. Doi: 10.28991/ESJ-2022-06-04-013 Full Text: PD

Modelling combustion reactions for gas flaring and its resulting emissions

AbstractFlaring of associated petroleum gas is an age long environmental concern which remains unabated. Flaring of gas maybe a very efficient combustion process especially steam/air assisted flare and more economical than utilization in some oil fields. However, it has serious implications for the environment. This study considered different reaction types and operating conditions for gas flaring. Six combustion equations were generated using the mass balance concept with varying air and combustion efficiency. These equations were coded with a computer program using 12 natural gas samples of different chemical composition and origin to predict the pattern of emission species from gas flaring. The effect of key parameters on the emission output is also shown. CO2, CO, NO, NO2 and SO2 are the anticipated non-hydrocarbon emissions of environmental concern. Results show that the quantity and pattern of these chemical species depended on percentage excess/deficiency of stoichiometric air, natural gas type, reaction type, carbon mass content, impurities, combustion efficiency of the flare system etc. These emissions degrade the environment and human life, so knowing the emission types, pattern and flaring conditions that this study predicts is of paramount importance to governments, environmental agencies and the oil and gas industry

Modelling emissions from natural gas flaring

The world today recognizes the significance of environmental sustainability to the development of nations. Hence, the role oil and gas industry plays in environmental degrading activities such as gas flaring is of global concern. This study presents material balance equations and predicts results for non-hydrocarbon emissions such as CO2, CO, NO, NO2, and SO2 etc. from flaring (combustion) of 12 natural gas samples representing composition of natural gas of global origin. Gaseous emission estimates and pattern were modelled by coding material balance equations for six reaction types and combustion conditions with a computer program. On the average, anticipated gaseous emissions from flaring natural gas with an average annual global flaring rate 126 bcm per year (between 2000 and 2011) in million metric tonnes (mmt) are 560 mmt, 48 mmt, 91 mmt, 93 mmt and 50 mmt for CO2, CO, NO, NO2 and SO2 respectively. This model predicted gaseous emissions based on the possible individual combustion types and conditions anticipated in gas flaring operation. It will assist in the effort by environmental agencies and all concerned to track and measure the extent of environmental pollution caused by gas flaring operations in the oil and gas industry

Modulating the electrocatalytic reduction of CO2 to CO via surface reconstruction of ZnO nanoshapes

The electrocatalytic conversion of carbon dioxide (CO2) into valuable chemicals presents a promising strategy for closing the carbon cycle. In this study, we synthesized zinc (Zn) catalysts through hydrothermal methods using either polyvinylpyrrolidone (PVP) or cetyltrimethylammonium bromide (CTAB) as stabilizing agents. These catalysts proved highly efficient in converting CO2 into carbon monoxide (CO). Our findings revealed that ZnO, synthesized with different morphologies—namely, nanoneedles (ZnO-NN) and nanorods (ZnO-NR)—underwent significant electro-reconstruction, ultimately leading to the formation of hexagonal metallic Zn crystals, regardless of their initial characteristics. Utilizing ex-situ operando techniques, we elucidated that metallic Zn serves as the active phase for the CO2-to-CO conversion process. In a comparison, ZnO-NN catalysts demonstrated superior selectivity and stability, achieving 91.3% CO selectivity at a potential of −0.88 V vs. RHE (Reversible Hydrogen Electrode) due to the facile transformation of ZnO to metallic Zn. Remarkably, these catalysts maintained this level of performance for more than 17 h. Conversely, ZnO-NR catalysts exhibited a lower CO selectivity of 62.5% at a relatively higher potential of −0.98 V vs RHE

IFRA Special Research Issue Vol. 2

The French Institute for Research in Africa (IFRA), Ibadan, a foundation of the French government, is a non-profit institute set up to promote research in the social sciences and humanities, as well as enhance collaborative work between scholars in France and West Africa. It was established in 1990 and operates from the University of Ibadan, Nigeria, where it is housed by the Institute of African Studies. IFRA mandate includes subsiding research programs, granting research allowances to academies and scholars, publishing research results, and holding workshops, seminars and symposia. Over the past few years, the research orientation of IFRA Ibadan has revolved around problems of democratic transition, urban violence and security, and religious networks in West Africa. The Institute also runs a library and publishes a Newsletter

Adaptation of the Wound Healing Questionnaire universal-reporter outcome measure for use in global surgery trials (TALON-1 study): mixed-methods study and Rasch analysis

BackgroundThe Bluebelle Wound Healing Questionnaire (WHQ) is a universal-reporter outcome measure developed in the UK for remote detection of surgical-site infection after abdominal surgery. This study aimed to explore cross-cultural equivalence, acceptability, and content validity of the WHQ for use across low- and middle-income countries, and to make recommendations for its adaptation.MethodsThis was a mixed-methods study within a trial (SWAT) embedded in an international randomized trial, conducted according to best practice guidelines, and co-produced with community and patient partners (TALON-1). Structured interviews and focus groups were used to gather data regarding cross-cultural, cross-contextual equivalence of the individual items and scale, and conduct a translatability assessment. Translation was completed into five languages in accordance with Mapi recommendations. Next, data from a prospective cohort (SWAT) were interpreted using Rasch analysis to explore scaling and measurement properties of the WHQ. Finally, qualitative and quantitative data were triangulated using a modified, exploratory, instrumental design model.ResultsIn the qualitative phase, 10 structured interviews and six focus groups took place with a total of 47 investigators across six countries. Themes related to comprehension, response mapping, retrieval, and judgement were identified with rich cross-cultural insights. In the quantitative phase, an exploratory Rasch model was fitted to data from 537 patients (369 excluding extremes). Owing to the number of extreme (floor) values, the overall level of power was low. The single WHQ scale satisfied tests of unidimensionality, indicating validity of the ordinal total WHQ score. There was significant overall model misfit of five items (5, 9, 14, 15, 16) and local dependency in 11 item pairs. The person separation index was estimated as 0.48 suggesting weak discrimination between classes, whereas Cronbach's α was high at 0.86. Triangulation of qualitative data with the Rasch analysis supported recommendations for cross-cultural adaptation of the WHQ items 1 (redness), 3 (clear fluid), 7 (deep wound opening), 10 (pain), 11 (fever), 15 (antibiotics), 16 (debridement), 18 (drainage), and 19 (reoperation). Changes to three item response categories (1, not at all; 2, a little; 3, a lot) were adopted for symptom items 1 to 10, and two categories (0, no; 1, yes) for item 11 (fever).ConclusionThis study made recommendations for cross-cultural adaptation of the WHQ for use in global surgical research and practice, using co-produced mixed-methods data from three continents. Translations are now available for implementation into remote wound assessment pathways