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Advancing respirable coal mine dust source apportionment:a preliminary laboratory exploration of optical microscopy as a novel monitoring tool

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International Journal of Coal Science & Technology 2024年第2期11卷 222-233页

作者： nestor Santa Emily Sarver Department of Mining and Minerals Engineering Virginia TechBlacksburgVA 24061USA

Exposure to respirable coal mine dust(RCMD)can cause chronic and debilitating lung ***-time monitoring capabilities are sought which can enable a better understanding of dust components and *** many underground mines,RCMD includes three primary components which can be loosely associated with three major dust sources:coal dust from the coal seam itself,silicates from the surrounding rock strata,and carbonates from the inert‘rock dust’products that are applied to mitigate explosion hazards.A monitor which can reliably partition RCMD between these three components could thus allow source *** tracking silicates,specifically,could be valuable since the most serious health risks are typically associated with this component-particularly if abundant in crystalline *** a monitoring concept based on field microscopy,and following up on prior research using polarized light,the aim of the current study was to build and test a model to classify respirable-sized particles as either coal,silicates,or *** model development,composite dust samples were generated in the laboratory by successively depositing dust from high-purity materials onto a sticky transparent substrate,and imaging after each deposition event such that the identity of each particle was known a *** testing followed a similar approach,except that real geologic materials were used as the source for each dust *** showed that the model had an overall accuracy of 86.5%,indicating that a field-microscopy based moni-tor could support RCMD source apportionment and silicates tracking in some coal mines.

关键词： Polarized light microscopy Image processing Dust monitoring Respirable silica Coal mining

Dynamics analysis and cryptographic implementation of a fractional-order memristive cellular neural network model

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Chinese Physics B 2024年第4期33卷 418-433页

作者：周新卫蒋东华 Jean De Dieu Nkapkop Musheer Ahmad Jules Tagne Fossi nestor Tsafack 吴建华 Department of Information Engineering Gongqing CollegeNanchang UniversityJiujiang 332020China School of Computer Science and Engineering Sun Yat-Sen UniversityGuangzhou 511400China Department of Electrical Engineering and Industrial Computing University Institute of TechnologyDoualaCameroon Department of Computer Engineering Jamia Millia IslamiaNew Delhi 110025India Department of Physics Faculty of ScienceUniversity of YaoundeCameroon Electrical Engineering Department and Industrial Computing of ISTAMA University of DoualaDoualaCameroon

Due to the fact that a memristor with memory properties is an ideal electronic component for implementation of the artificial neural synaptic function,a brand-new tristable locally active memristor model is first proposed in this ***,a novel four-dimensional fractional-order memristive cellular neural network(Fo-MCNN)model with hidden attractors is constructed to enhance the engineering feasibility of the original CNN model and its ***,its hardware circuit implementation and complicated dynamic properties are investigated on multi-simulation ***,it is used toward secure communication application *** it as the pseudo-random number generator(PRNG),a new privacy image security scheme is designed based on the adaptive sampling rate compressive sensing(ASR-CS)***,the simulation analysis and comparative experiments manifest that the proposed data encryption scheme possesses strong immunity against various security attack models and satisfactory compression performance.

关键词： cellular neural network memristor hardware circuit compressive sensing privacy data protection

Male and Female Hypogonadisms: Etiological, Metabolic and osteodensitometric Aspects

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open Journal of Endocrine and Metabolic Diseases 2024年第2期14卷 39-52页

作者： nestor Ghislain Andzouana Mbamognoua Ikram Damoune Sana Doubi Asmae Lahlou Farida Ajdi Department of Metabolic and Endocrine Diseases Brazzaville University Hospital Brazzaville Republic of the Congo Faculty of Health Sciences Marien Ngouabi University Brazzaville Republic of Congo Department of Endocrinology Metabolic Diseases Hassan II University Hospital of Fez Fez Morocco

Introduction: Studies showed a high prevalence of metabolic abnormalities including dyslipidemia, type 2 diabetes in cases of low testosterone in men and which are associated with increased cardiovascular risk. Hypogonadism represents the second cause of endocrine osteoporosis. objectives: The objectives of our work were: to determine the main causes of hypogonadism in women and men;to assess the frequency of metabolic and osteosdensitometric abnormalities in the hypogonadal population. Patients and methods: A retrospective descriptive study was carried out over 7 years on 120 patients, hospitalized in the Endocrinology department of the Hassan II University Hospital of Fez-Morocco for hypogonadism. The patients selected were those who had symptoms of hypogonadism confirmed in men by: low total testosterone for Tanner stage in adolescents, ng/ml or lower limit of normal for adults;in women, hypoestrogenia 30 pg/l. Gonadotropin dosage, karyotype, pelvic or testicular ultrasound and pituitary MRI, for etiological diagnosis, were performed. Bone densitometry was performed for bone impact and lipid profile for metabolic profile. Results: out of 120 patients, there were 77 women and 43 men. The average age was 31.51 years. In men, the main causes were central hypogonadism in 67.4% and primary testicular failure in 32.6%. In women, central hypogonadism was also the most common cause noted in 63.7% and premature ovarian failure was observed in 36.4%. HypoHDL was significantly more frequent p (0.005) in women, osteopenia and osteoporosis were significantly more frequent in women than in men p (0.046). Conclusion: Central causes represent the most common etiology of hypogonadism in both sexes;abnormalities of bone mineralization and metabolic disorders were predominant in women.

关键词： Hypogonadism Etiological Metabolic osteodensitometric Fez

optimization of the Pretreatment of the Mixture of Cassava Peelings and Pineapple Fibers Using Response Surface Methodology and a Process Simulator for the Bioethanol Production

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Energy and Power Engineering 2024年第2期16卷 79-96页

作者： Paul nestor Djomou Djonga George Elambo Nkeng Madjoyogo Hervé Sirma Ahmat Tom Thierry Tchamba Tchuidjang Department of Textile and Leather Engineering National Advanced School of Engineering of Maroua Maroua Cameroon Department of Civil Environmental and Architectural Engineering University of Padova Padova Italy Institut du Génie des Systèmes Industriels et textiles Ecole Polytechnique de Ouagadougou Ouagadougou Burkina-Faso Department of Energy Engineering University Institute of Technology University of Ngaoundere Ngaoundere Cameroon Department of Process Engineering National Advanced School of Agro-Industrial Sciences University of Ngaoundere Ngaoundere Cameroon

The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min-1, 5358.1461 J·mol-1, 1383.03691 min-1, 51577.6100 J·mol-1 respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.

关键词： Bioethanol Cassava Peeling Pineapple Fibers organosolv Process and optimization

Assessment of Cement-Lime as Stabilizer on Mud Bricks

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Journal of Materials Science and Chemical Engineering 2024年第7期12卷 1-13页

作者： Chrisdel Chancelice Ndjeumi Djonga Paul nestor Djomou George Elambo Nkeng Fatoumata Adda Souaibou Soulemane Anong Department of Environmental Sciences ENSPM University of Maroua Maroua Cameroon Department of Leather and Textile Engineering ENSPM University of Maroua Maroua Cameroon Department of Civil Environmental and Architectural Engineering University of Padova Padova Italy Laboratory of Analysis of CIMENCAM Garoua Cameroon

The aim of this study was to evaluate the compressive strength of clay bricks and their stability to water absorption by inserting stabilizers such as lime and cement of 0%, 4%, 6%, 8%, 10%, 12% to 14%. Spectrometric analysis was used to characterize the various stabilizers and the clay used, and tests of resistance and water absorption were also carried out. The clay was found to be an aluminosilicate (15.55% to 17.17% Al2o3 and 42.12% to 44.15% Sio2). The lime contains 90.84% Cao and the cement has 17.80% Sio2, 3.46% Al2o3, 2.43% Fe2o3 and 58.47% Cao in the combined form of tricalcium silicate, dicalcium silicate, tricalcium aluminate and ferro-tetra calcium aluminate. The results showed that the insertion of locally available stabilizers (lime and cement) improved the strength of the material by almost 80% when the lime was increased from 0% to 14% for 14 days. For compressed cement, a 65% increase in strength was observed under the same conditions. Strength increases with drying time, with a 52% increase in strength at 28 days compared to 14 days. Furthermore, compressed cement bricks have a more compact structure, absorbing very little water (32%). In view of all these results, cement appears to be the best stabilizer, and compression improves compressive strength and reduces water absorption.

关键词： Cement-Stabilized Earth Lime-Stabilized Earth Compressed Earth Brick Compressive Strength Water Absorption Test

Composite Panels from the Combination of Rice Husk and Wood Chips with a Natural Resin Based on Tannins Reinforced with Sugar Cane Molasses Intended for Building Insulation: Physico-Mechanical and Thermal Properties

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Journal of Materials Science and Chemical Engineering 2024年第2期12卷 19-30页

作者： Paul nestor Djomou Djonga Rosellyne Serewane Deramne Gustave Assoualaye Ahmat Tom Tégawendé Justin Zaida Department of Textile and Leather Engineering National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon Department of Chemistry Faculty of Science University of Bangui Bangui Central African Republic Department of Renewable Energy National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon Department of Energy Engineering University Institute of Technology University of Ngaoundere Ngaoundere Cameroon Institute of Industrial and Textile Systems Engineering Ecole Polytechnique de Ouagadougou Ouagadougou Burkina Faso

The objective of this work is to develop new biosourced insulating composites from rice husks and wood chips that can be used in the building sector. It appears from the properties of the precursors that rice chips and husks are materials which can have good thermal conductivity and therefore the combination of these precursors could make it possible to obtain panels with good insulating properties. With regard to environmental and climatic constraints, the composite panels formulated at various rates were tested and the physico-mechanical and thermal properties showed that it was essential to add a crosslinker in order to increase certain solicitation. an incorporation rate of 12% to 30% made it possible to obtain panels with low thermal conductivity, a low surface water absorption capacity and which gives the composite good thermal insulation and will find many applications in the construction and real estate sector. Finally, new solutions to improve the fire reaction of the insulation panels are tested which allows to identify suitable solutions for the developed composites. In view of the flame tests, the panels obtained are good and can effectively combat fire safety in public buildings.

关键词： Composite Panels Tannins Reinforced Sugar Cane Molasses Building Insulation Mechanical and Thermal Properties

Diversity of Macro Invertebrates of the River Rwizi in Western Uganda: A Citizen Science-BioBlitz Approach

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open Journal of Ecology 2024年第4期14卷 343-365页

作者： John Bosco Nkurunungi Godwin Muhairwe Upton Nuwagira Nickson Araka nestor Mugabe osbert Natwijuka Jeninah Atwebembeire Mbarara University of Science and Technology Mbarara Uganda Department of Directorate of Research and Graduate Training Makerere University Kampala Uganda

This study elucidates the pivotal role of citizen science-BioBlitz methodologies for rapid assessment of the macro-invertebrate taxa within the threatened River Rwizi of South-western Uganda. Utilizing a comprehensive mixed-methods approach, the investigation focused on six distinct river segments to demonstrate the efficacy of participatory citizen science-BioBlitz approaches conducted by experts, students and community volunteers. BioBlitz events included rigorous macro-invertebrate sampling at each of the selected sites along River Rwizi on nine occasions, incorporating collaborative taxonomic identification procedures involving experts, students, and the local community. Analyzing pollution concerns, diversity metrics, and community narratives yielded insights into river health and socio-ecological dynamics. A total of 43 macro-invertebrate families across 17 orders were documented with class Insecta dominating. Participants in BioBlitz events expressed predominantly positive sentiments, emphasizing satisfaction, education, and heightened awareness, besides negative sentiments rooted in historical mistrust. Intriguingly, the study unveiled an unforeseen trend in macro-invertebrate taxa richness, rising from upstream to urban sprawl and diminishing at peri-urban downstream sites. The study underscores the potential of citizen science-BioBlitz methodologies in advancing community science education and unraveling the intricate dynamics of threatened river ecosystems. The insights offered are invaluable for policymakers and conservationists seeking effective strategies to address challenges in the River Rwizi and comparable ecosystems. .

关键词： Diversity Macroinvertebrates Rwizi Citizen-Science-BioBlitz 6

Climate-influenced vector-borne diseases in Africa: a call to empower the next generation of African researchers for sustainable solutions

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贫困所致传染病(英文) 2024年第2期13卷 1-10页

作者： obame-Nkoghe Judica?l Agossou Adjoavi Esse Mboowa Gerald Kamgang Basile Caminade Cyril Duke Dawn C. Githeko Andrew Karanja ogega obed M. Elloué nestor Engone Sarr Fatou Bintou Nkoghe Dieudonné Kengne Pierre Ndam Nicaise T. Paupy Christophe Bockarie Moses otomo Patricks Voua Molecular and Cellular Biology Laboratory (LabMC) Biology Department University of Science and Technology of Masuku BP Franceville Gabon Ecology and Health Research Unit Interdisciplinary Center for Medical Research of Franceville BP Franceville Gabon Department of Zoology and Entomology Faculty of Natural and Agricultural Sciences University of the Free State Private Bag x13 Phuthaditjhaba Republic of South Africa Laboratory of Pharmacology and Improved Traditional Medicines Department of Animal Physiology Faculty of Science and Technology University of Abomey-Calavi BP Cotonou Benin The African Center of Excellence in Bioinformatics and Data-Intensive Sciences Infectious Diseases Institute College of Health Sciences Makerere University P. O Box Kampala Uganda Africa Centers for Disease Control and Prevention African Union Commission Roosevelt Street P.O. Box WKAddis Ababa Ethiopia Centre for Research in Infectious Diseases P.O. Box Yaoundé Cameroon Earth System Physics Department The Abdus Salam International Centre for Theoretical Physics Trieste Italy Africa Research Excellence Fund Charterhouse Street London EC1MHR UK Community Health Support Program P.O. Box Kisumu Kenya The African Academy of Sciences Nairobi Kenya Center for Phylosophical Studies and Research (CERP) Omar Bongo University (UOB) BP Libreville Gabon UMRED Health Training and Research Unit University of Iba Der Thiam of Thiès BP Thiès Senegal National Parasitic Diseases Control Program Ministry of Health Libreville Gabon MIVEGEC Univ. Montpellier CNRS IRD Montpellier France MERIT IRD Paris Cité University Paris France Department of Parasitology Noguchi Memorial Institute for Medical Research University of Ghana LG Accra Ghana School of Community Health Sciences Njala University Bo Sierra Leone

We look at the link between climate change and vector-borne diseases in low- and middle-income countries in Africa. The large endemicity and escalating threat of diseases such as malaria and arboviral diseases, intensified by climate change, disproportionately affects vulnerable communities globally. We highlight the urgency of prioritizing research and development, advocating for robust scientific inquiry to promote adaptation strategies, and the vital role that the next generation of African research leaders will play in addressing these challenges. Despite significant challenges such as funding shortages within countries, various pan-African-oriented funding bodies such as the African Academy of Sciences, the Africa Research Excellence Fund, the Wellcome Trust, the U.S. National Institutes of Health, and the Bill and Melinda Gates Foundation as well as initiatives such as the African Research Initiative for Scientific Excellence and the Pan-African Mosquito Control Association, have empowered (or are empowering) these researchers by supporting capacity building activities, including continental and global networking, skill development, mentoring, and African-led research. This article underscores the urgency of increased national investment in research, proposing the establishment of research government agencies to drive evidence-based interventions. Collaboration between governments and scientific communities, sustained by pan-African funding bodies, is crucial. Through these efforts, African nations are likely to enhance the resilience and adaptive capacity of their systems and communities by navigating these challenges effectively, fostering scientific excellence and implementing transformative solutions against climate-sensitive vector-borne diseases.

关键词： Climate change Vector-borne diseases Africa Environmental justice Research and development Pan-African funding initiatives

Multi-Scale Approach for Gold Targeting in Côte d’Ivoire Paleoproterozoic Rocks

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open Journal of Geology 2024年第2期14卷 155-176页

作者： Martial Pohn Koffi Adingra Yao Augustin Koffi N’guessan nestor Houssou Zié ouattara Tokpa Kakeu Lionel-Dimitri Boya Marc Ephrem Allialy Training and Research Unit in Earth Sciences and Mineral Resources Laboratory of Geology Mineral and Energy Resources University Felix HOUPHOU&#203T-BOIGNY Abidjan C&#244te d’Ivoire Training and Research Unit in Geological Sciences and Mining Department of Geology and Material Man University Man C&#244te d’Ivoire

The aim of this study is to contribute to better targeting of gold prospecting areas using geospatial information. To this end, 3 mining sites were selected for the study. They are: the Sénoufo belt (Barrick Gold mine), the Yaouré complex (Perseus Mining mine) and the South Fetêkro belt (Bonikro, Hiré and Agbaou mines). For this study, a multi-scale approach was carried out at regional, mine and microscopic levels. At the regional scale, a comparative analysis of 1:200,000 scale geological maps revealed that 3 main lithologies are regularly repeated on and around the various mining sites. These are: undifferentiated volcanics, metagranodiorites and metasiltites dominated by meta-arenites. Most of these lithologies are affected by undifferentiated faults generally oriented NE-SW, N-S, ENE-WSW and WNW-ESE. In addition, gold and manganese occurrences are present on all the sites studied. At the mine scale, radarsat-1 images processing indicate that the main mining sites are generally located near or at the intersection of lineaments-oriented NE-SW or N-S on the one hand and E-W or ENE-WSW or WNW-ESE or again NW-SE on the other. These mines are also located at the interface between zones of high and low lineament density. At the microscopic scale, petrographic studies of undifferentiated volcanic samples from the various sites indicate that they consist of andesites, meta-andesites and tuffs.

关键词： Gold Targeting Undifferentiated Volcanics Mineral occurrences Lineaments Côte d’Ivoire