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An Investigation into Forced Convection of a Nanofluid Flowing in a Rectangular Microchannel under the Influence of a Magnetic Field

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Fluid Dynamics & Materials Processing 2024年第2期20卷 311-323页

作者： Muataz S.Alhassan Ameer A.Alameri Andrés alexis Ramírez-Coronel I.B.Sapaev Azher M.abed David-Juan Ramos-Huallpartupa Rahman S.Zabibah Division of Advanced Nanomaterial Technologies Scientific Research CenterAl-Ayen UniversityThi-QarIraq Department of Chemistry College of ScienceUniversity of BabylonBabylonIraq Research Group in Educational Statistics National University of EducatiosnAzoguesEcuador Department Physics and Chemistry Tashkent Institute of Irrigation and Agricultural Mechanization EngineersNational Research UniversityTashkentUzbekistan Akfa University TashkentUzbekistan New Uzbekistan University TashkentUzbekistan Department of Airconditioning and Refrigeration Engineering Al-Mustaqbal University CollegeHilla51001Iraq Academic Department of Agro-Industrial Engineering and Technology Universidad Nacional JoséMaría ArguedasApurimacPerú The Islamic University NajafIraq

In line with recent studies,where it has been shown that nanoﬂuids containing graphene have a stronger capacity to boost the heat transfer coefﬁcient with respect to ordinary nanoﬂuids,experiments have been conducted using water with cobalt ferrite/graphene *** particular,a circular channel made of copper subjected to a constant heatﬂux has been *** nanoparticles are sensitive to the presence of a magneticﬁeld,different conditions have been examined,allowing both the strength and the frequency of such aﬁeld to span relatively wide ranges and assuming different concentrations of *** to theﬁndings,the addition of nanoparticles to theﬂuid causes its rotation speed to increase by a factor of two,whereas ultraviolet radiation plays a negligible *** amount of time required to attain the maximum rotation speed of the nanoﬂuid and the Nusselt number have been measured under both constant and alternating magneticﬁelds for a ferroﬂuid with a concentration of 0.5%and atﬂow Reynolds number of 550 and 1750.

关键词： Nano fluid rectengular tube magnetic field

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Fruit Powder of Tetrapleura tetraptera in Local Feed on Some Zootechnical Performances of Juveniles of Clarias gariepinus in Concrete Tank

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Open Journal of Animal Sciences 2024年第2期14卷 56-69页

作者： Ngouana Tadjong Ruben abdoulaye abdoulaye Kana Jean Raphaël Téguia alexis Laboratory of Aquaculture and Demography of Fisheries Resources Aquaculture Department Institute of Fisheries and Aquatic Science of Yabassi University of Douala Douala Cameroon Laboratory of Animal Nutrition Department of Animal Science Faculty of Agronomy and Agricultural Sciences University of Dschang Dschang Cameroon

This study focused on the supplementation of four-sided spice fruit powder (Tetrapleura tetraptera) on some zootechnical performances of juveniles of Clarias gariepinus and was carried out from February 14 to July 20 at the Massoma Fish Farm of Bojongo Mbeidi located in the Littoral Region, Department of Wouri, Douala IV district. The farm benefits from a climate favorable to aquaculture activity. For this purpose, five (5) treatments were tested including T0+ (imported feed), T0-, T0.3, T0.4, and T0.5 respectively for the treatments with 0% supplemented food;0.3%;0.4% and 0.5% of Tetrapleura tetraptera powder. A total of 450 Clarias gariepinus fry with an initial average weight of 7 ± 1.5 g, were distributed in happas of 0.49 m2 each placed in Triplicate in a completely randomized device. Four isoprotein foods with 38% crude protein were formulated to feed these fry at 7% of their biomass per day for 15 days then to their fullness until the end of the experiment. Intermediate fishing was carried out every fortnight. 75 days later, the results recorded show that the highest average survival rate (96.44% ± 3.5%) was recorded with the subjects fed feed supplemented with 0.4% T. tetraptera powder. The average weight (120.93 ± 67.20), weight gain (113.93 ± 67.20), specific growth rate (3.64 ± 0.79% g/d) and total lengths and standard (26.43 ± 1.9 and 23.66 ± 1.76) the highest were recorded with the T0+ treatment (imported feed). The highest conditioning factor K (2.14 ± 0.15) was recorded with the treatment supplemented with 0.4% T. tetraptera. The lowest conversion ratio (1.28) was recorded with the treatment fed with imported blue crown food (T0+). Furthermore, the lowest production cost was recorded with the treatment supplemented with 0.4% T. tetraptera. It appears from this study that the juveniles of C. gariepinus better value the feed substituted with 0.4% of the powder of fou

关键词： Tetrapleura tetraptera Local Feed Zootechnical Performance Juvenile of Clarias gariepinus

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Allophane as a Nanotechnological Additive in Masonry Materials to Increase Resistance and Waterproofing

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Advances in Materials Physics and Chemistry 2024年第8期14卷 196-212页

作者： Edward H. Jiménez Joao Rivera Juan H. Villalba Paola E. Vera Marlon Cuenca Belén Granja Javier Fuentes Sandra Gavilanes Daniel Hidalgo Fernando Garcia jose Bermudez Washington Ruiz alexis Martial Debut Facultad de Ingeniera Qumica Universidad Central del Ecuador Quito Ecuador Facultad de Arquitectura y Urbanismo Universidad Central del Ecuador Quito Ecuador Nanomaterials Characterization Laboratory Universidad de las Fuerzas Armadas ESPE Sangolqu Ecuador

The constant need for high-strength materials in the construction industry promotes the research of additives that improve the properties of masonry materials. The use of allophane as an additive in concrete and mortar mixtures was implemented to improve their strength and waterproofing, respectively, using compression and water absorption tests according to their corresponding standards (ASTM C1231, ASTM D2938, and ASTM C1585). The samples were evaluated at different concentrations and curing ages. In addition, different sand/cement ratios were considered for the mortar. The results revealed that there was a 9.4% increase in compressive strength in concrete and a 23.7% reduction in water absorption in mortar for the 5:1 ratio. These changes would be the result of the interaction of the nanoporous additive in the atomic crystal structure of the material demonstrating the nanotechnological nature of allophane.

关键词： Allophane Nano Additive Strength Impermeability Concrete Mortar

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Comparative Study of the Reliability and Complexity of Symmetrical and Asymmetrical Cryptosystems for the Protection of Academic Data in the Democratic Republic of Congo

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Journal of Information Security 2024年第3期15卷 299-307页

作者： Mugaruka Buduge Gulain Jeremie Ndikumagenge Buhendwa Nyenyezi Justin Bulonza Masumbuko alexis Katho Seba Jacques Department of Management Computing for Companies Section of Commercial and Computing Sciences Teachers Training College of Bukavu Bukavu The Democratic Republic of the Congo Center of Research in Infracture Environment and Technology (CRIET) Doctoral School University of Burundi Bujumbura Burundi Department of Maths-Physics Section of Exact Sciences Teachers Training College of Bukavu Bukavu The Democratic Republic of the Congo Higher Institute of Medical Techniques of Bukavu Bukavu The Democratic Republic of the Congo Department of Maths-Physics Section of Exact Sciences Teachers Training College of Bunia Bunia The Democratic Republic of the Congo

In the digital age, the data exchanged within a company is a wealth of knowledge. The survival, growth and influence of a company in the short, medium and long term depend on it. Indeed, it is the lifeblood of any modern company. A companys operational and historical data contains strategic and operational knowledge of ever-increasing added value. The emergence of a new paradigm: big data. Today, the value of the data scattered throughout this mother of knowledge is calculated in billions of dollars, depending on its size, scope and area of intervention. With the rise of computer networks and distributed systems, the threats to these sensitive resources have steadily increased, jeopardizing the existence of the company itself by drying up production and losing the interest of customers and suppliers. These threats range from sabotage to bankruptcy. For several decades now, most companies have been using encryption algorithms to protect and secure their information systems against the threats and dangers posed by the inherent vulnerabilities of their infrastructure and the current economic climate. This vulnerability requires companies to make the right choice of algorithms to implement in their management systems. For this reason, the present work aims to carry out a comparative study of the reliability and effectiveness of symmetrical and asymmetrical cryptosystems, in order to identify one or more suitable for securing academic data in the DRC. The analysis of the robustness of commonly used symmetric and asymmetric cryptosystems will be the subject of simulations in this article.

关键词： Comparative Study Cryptosystems Symmetric Encryption Asymmetric Encryption

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Evaluation of the Reproduction Parameters of “Lohmann Brown” Strain Chickens Fed with Cajanus cajan Leaf Meal in the Republic of Congo

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Open Journal of Animal Sciences 2024年第3期14卷 234-248页

作者： Richard Missoko Mabeki alexis Jonas Ognika Dora Chérita Ekou Nathalie Myreille Ockoyi Parisse Akouango Laboratory of Animal Production and Biodiversity National School of Agronomy and Forestry Marien Ngouabi University Brazzaville Republic of the Congo Department of Animal Production and Health Marien Ngouabi University Brazzaville Republic of the Congo

The objective of this study was to evaluate the reproductive parameters of “Lohmann Brown” strain chickens fed on Cajanus cajan leaves and to assess the viability of the chicks after hatching. 40 hens of the “Lohmann Brown” strain fed on Cajanus cajan leaf flour laid 219 eggs divided into four batches depending on the rate of incorporation of Cajanus cajan leaf flour in the rations (0%, 5%, 10% and 15%) were trained and introduced into the incubator. Results: the incubator indicates a hatching temperature of 38˚C to 37.2˚C and relative humidity of 60% to 70%. Hatching performance shows that: The 15% batch recorded the highest fertility rate 86.95% compared to 26.88% of the control batch. The CC 15% batch recorded the highest hatching rate 36.87. The lowest rate (17.18%) was recorded in the control batch (CC 0%). The highest embryonic mortality rate was recorded in the CC 15% batch. The lowest rate in the CC 10% batch. Concerning unfertilized eggs, the highest rate is 72.20% (CC 0%), and the lowest are (12.03%;57.42% and 66.66%) recorded in CC batches. 15%, CC 5% and CC 10% respectively. For the shell mortality rate, the highest is 18.58% recorded in the CC 15% batch. The lowest shell mortality rate is 2.07%, obtained in the control batch (CC 0%);the dust mortality rate was 0% for all chicks. The study seems to indicate that the incorporation of Cajanus cajan leaf meal up to 15% into the reproduction type ration in hens does not cause any harmful effects on the reproduction performance of laying hens.

关键词： Egg Incubation Hatching Fertility Mortality Viability

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Physico-Chemical Characterization of Some Honeys from the Savannah-Gallery Forest Complex and Primary Forest in Gabon

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Open Journal of Applied Sciences 2024年第7期14卷 1904-1917页

作者： Charline Obone Madi Guirema abaker Silas Davy Mbadinga Boubala Estelle Dumont Gino Boussiengui-Boussiengui alexis Nicaise Lepengue Dpartement Sciences Fondamental de lIngnieur Institut National Suprieur dAgronomie et de Biotechnologies Universit des Sciences et Techniques de Masuku Franceville Gabon Dpartement de Biochimie Facult des Sciences Universit des Sciences et Techniques de Masuku Franceville Gabon Laboratoire de Recherche Multidisciplinaire en Environnement (LARME) USTM Franceville Gabon Dpartement de Phytotechnologie Institut National Suprieur dAgronomie et de Biotechnologies Universit des Sciences et Techniques de Masuku Franceville Gabon

Honey harvesting throughout beekeeping is a technology recently introduced in Gabon comparing to the other African countries well known in international honey trade. The purpose of this study is to contribute to the knowledge of the quality of multi-flower honeys from the savannah-gallery forest complex and primary forest not well documented in Gabon. Physical and chemical parameters of different honeys were analyzed using the official methods of analysis of the Association of Official Analytical Chemists. The results of physico-chemical analysis show variations in pH (3.4 to 3.9), free acidity (37.12 to 76.65 meq∙kg−1), water content (17.49% to 21.21%), electrical conductivity (0.64 to 1.24 mS∙cm−1), density (1.02 to 1.03) and total sugar content (77% to 82%). These variations were significantly different (p < 0.05) between certain honeys, but independent of the type of ecosystem considered. The pH values confirmed the botanical origin of the five honeys. The physico-chemical parameters of the honeys show significant correlations (p < 0.05). Moisture content is negatively correlated with conductivity (r = −0.628), pH (r = −0.631), density (r = −0.552) and total sugar content (r = −0.890). Conductivity is positively correlated with free acidity (r = 0.688) and total sugar content (r = 0.776), and negatively correlated with water content (r = −0.628). All honeys were in line with Codex Alimentarius standards, except for 3 types of honey (M1, M2 and M4) for free acidity and electrical conductivity, showing possible fermentation of these honeys.

关键词： Physico-Chemical Parameters Honey Gabon Codex Alimentarius

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盒子外的生活巴厘岛私宅

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室内设计与装修 2024年第2期 18-23页

作者： [印度尼西亚]alexis Dornier 小麦(编译) 不详

这是坐落在巴厘岛郁郁葱葱丛林中的一座住宅。设计师从自然之美和挑战建筑规模的愿望中汲取灵感,以迷人的8字螺旋形创造出连续而流畅的建筑空间,希望将人们从无趣且程式化的、如“盒子”一般的生活中抽离出来,拥抱自由的精神。住宅特殊... 详细信息

这是坐落在巴厘岛郁郁葱葱丛林中的一座住宅。设计师从自然之美和挑战建筑规模的愿望中汲取灵感,以迷人的8字螺旋形创造出连续而流畅的建筑空间,希望将人们从无趣且程式化的、如“盒子”一般的生活中抽离出来,拥抱自由的精神。住宅特殊的辐射状设计,为居住者提供了一种迷人而身临其境的体验,邀请人们拥抱一种全新而自由的生活方式。

关键词：自然之美辐射状丛林中巴厘岛居住者自由螺旋形身临其境

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Birds’Diversity in Kalfou Forest Reserve and Its Peripheral Zone, Far North, Cameroon

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Open Journal of Animal Sciences 2024年第2期14卷 137-155页

作者： Ghislain Noé Kougoum Piebeng Simon A. Tamungang Daksala Wansang Jean Tonleu Laurentine Soufo Muhammad Bilal Awa II Taku alexis Teguia Department of Biological Sciences Faculty of Science University of Maroua Maroua Cameroon Department of Animal Biology Faculty of Science University of Dschang Dschang Cameroon Department of Forestry and Wildlife Technology College of Technology University of Bamenda Bamenda Cameroon Department of Environmental Sciences Higher Polytechnical Training School University of Maroua Maroua Cameroon Department of Biology Virtual University of Pakistan Rawalpindi Campus Punjab Pakistan Department of Animal Production Faculty of Agronomy and Agricultural Science University of Dschang Dschang Cameroon

The Far North Region of Cameroon is home to a great diversity of bird species, which unfortunately remains very little explored. This work was initiated to establish an inventory of birds and the factors affecting their diversity and distribution for sustainable management in the Kalfou Forest Reserve (KFR) and its periphery. Two methods were used for sampling, linear strip transects from which direct counts and indirect observations were made and the mist netting to complement the first. In total, 2525 birds were observed, including 149 species, belonging to 20 orders and 55 families. Accipitridae had the greatest number of species (11). The species richness was greater in the KFR (117 species) compared to the periphery (95 species). The specific richness was higher in wooded savannah compared to other habitats. Shannon index was significantly higher in the KFR (3.99) compared to that obtained in the periphery (3.80). The value of the Simpson index was higher on the outskirts of the KFR than on the periphery. The indices of species diversity were greater in the wooded savannah compared to other vegetation types. The seasons had no influence on bird diversity. Among the human activities encountered, the pressure indices were more important for grazing (7.3 contacts/km). Human activities have resulted in a significant decrease in specific richness. Six endangered species were encountered, four belonging to the Accipitridae family. The greater bird diversity in the reserve compared to the periphery shows that protected areas are a long-term solution for biodiversity conservation.

关键词： Bird Diversity Habitats Bird Species Human Activities Conservation Kalfou

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Functional Capacity of Patients with Venous Thromboembolic Disease Six to Twelve Months after Treatment

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World Journal of Cardiovascular Diseases 2024年第2期14卷 88-98页

作者： Hamadou Bâ Chris-Nadège Nganou-Gnindjio alexis Noé S. Guiakam Kemnang Yemele Honore Danwe Dieudonné Guy S. Wafeu Faculty of Medicine and Biomedical Sciences University of Yaoundé I Yaoundé Cameroon Cardiology Department Yaoundé Central Hospital Yaoundé Cameroon Centre for Research on Filariasis and Other Tropical Diseases Yaoundé Cameroon

Background: Venous thromboembolism (VTE) is among the leading causes of hospital-related disability-adjusted life years lost. We aimed to determine the prevalence and determinants of functional capacity impairment six to twelve months after an acute VTE event. Methods: This was a cross-sectional study conducted between January and April 2021 in two referral hospitals of Yaoundé, including consenting adult patients admitted to these hospitals six to twelve months ago for VTE. We excluded dead patients and those with any comorbidity or symptoms limiting physical activity. The functional outcome was assessed with the six-minute walk test. Functional capacity impairment was defined as walking distance lower than the expected value. Results: We included 27 cases in this study with a mean age of 53.2 ± 14.4 years. The prevalence of functional capacity impairment was 29.6% (95% CI: 14.8 - 48.1). Factors associated with poor functional outcome were obesity (OR: 59.5;95% CI: 4.6 - 767.2;p - 207.4;p = 0.017), massive PE (OR: 30;95% CI: 2.5 - 354;p = 0.004), and poor adherence to treatment (OR: 30.3;95% CI: 2.5 - 333.3;p = 0.004). Conclusion: Functional capacity impairment is common in the medium-term after VTE and factors associated with this poor outcome are obesity, the severity of the VTE, and poor adherence to treatment.

关键词： Functional Capacity Venous Thromboembolism Six-Minute Walk Test Cameroon

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Post Blast Tympanic Perforations, Clinical and Paraclinical Study at Six Yaounde Hospitals

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International Journal of Otolaryngology and Head & Neck Surgery 2024年第2期13卷 126-134页

作者： Andjock Nkouo Yves Christian Lekassa Pierrette Meva’a Biouele Roger Christian Moboung Prudence Mindja Eko David Djomou Francois Njock Richard Ndjolo alexis Ophthalmology-Ear-Nose-Throat (ENT)-Stomatology Department Faculty of Medicine and Biomedical Sciences University of Yaounde I Yaounde Cameroon ENT-Cervico-Facial-Surgery (CFS) Service Yaounde General Hospital Yaounde Cameroon ENT-CFS Service Omar Bongo Ondimba Military Teaching Hospital Libreville Gabon ENT-CFS Service Yaounde Central Hospital Yaounde Cameroon ENT-CFS Service Yaounde Teaching Hospital Yaounde Cameroon ENT-CFS Service Douala General Hospital Douala Cameroon

Introduction: Post-blast tympanic perforations represent an entity of traumatic perforations;various mechanisms are at the origin of the latter, and the increase in conflicts and acts of violence are increasing the studies on this subject, but few data are available in our context. Objective: This paper aims to study post-blast tympanic perforations in Yaounde, specifically the epidemiological, clinical, and paraclinical aspects. Methodology: We conducted a descriptive cross-sectional study with retrospective and prospective data collection in six Yaounde hospitals over 63 months from January 1, 2018, to March 31, 2023. All patients with at least one post-blast tympanic perforation were included. Socio-demographic, clinical and paraclinical data were collected on a questionnaire and analysed using SPSS 28 software. Results: We included 124 patients. The prevalence of post-blast tympanic perforations was 0.1% of the consultations in the departments. 71 The average age was 28.6 ± 9.1 years, with extremes ranging from 7 to 49 years. The median consultation time was five days. The most frequent injury circumstances were physical aggression (81.45%) and armed conflict (10.5%). The injury mechanisms were slaps (75%), punches (21.74%) and grenades (4.8%). The main symptoms on admission were hearing loss (63.7%), tinnitus (58.1%) and otalgia (57.3%). The tympanic perforations were unilateral in all cases, the anterior-inferior location was more characteristic, and the deafness was conductive in 58.3% of cases, followed by mixed deafness in 23.3% of cases. Conclusion: Post-blast tympanic perforations are rare in consultation. The population is primarily male and from the second decade of life. The main circumstance is aggression.

关键词： Tympanic Perforation Blast Yaounde

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