检索结果-南通市图书馆

Physico-Mechanical Characteristics of Earth Bricks Stabilized with Cement and Padouk Sawdust Residues

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第7期14卷 1788-1806页

作者： Gabin Alex Nouemssi Bennis Amine Martin Ndibi Mbozo’O bonaventure Djeumako Doko K. Valery Guy Edgar Ntamack LA2MP: Laboratory of Mechanics Materials and Photonics National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun Department of Mechanical and Production Engineering National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun LMTM: Laboratory of Mechanics Materials and Thermal National School of Mineral Industry ENIM Rabat Morocco LEMA: Laboratory of Energertic and Applied Mechanics University of Abomey-Calavi Cotonou Benin GMMA: Group of Mechanics Materials and Acoustics Department of Physics Faculty of Sciences-EGCIM Ngaoundr Cameroun

The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the Ndé department of Cameroon. To achieve this, two stabilizers, cement and sawdust, were used at varying percentages of 0%, 4%, 6%, and 8%. Physical characterization tests, including natural water content, specific weight, jar test, Protor, and Atterberg limits, were conducted. Additionally, mechanical tests, such as compression and three-point bending, were performed. The results show that as the amount of stabilizer increases, the density of BTC decreases. The samples with 8% sawdust have the highest density, while those without stabilizers have the lowest. Porosity decreases as sawdust and cement content increases, with smaller values observed in samples with 8% sawdust or cement. Our tests indicate that blocks stabilized with cement have slightly higher compressive strength than those stabilized with sawdust. However, the water absorption rate increases with higher sawdust content.

关键词： Earth block Cement Sawdust Physico-mechanical Characteristics Bangante West Cameroon

Improved deterministic reserve allocation method for multi-area unit scheduling and dispatch under wind uncertainty

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1142-1154页

作者： Jules bonaventure Mogo Innocent KAMWA Department of Electrical and Computer Engineering Laval UniversityQuebec G1V 0A6Canada Power System and Mathematics Hydro-Quebec/IREQVarennes J3X 1S1Canada

This paper presents a security constrained unit commitment(SCUC)suitable for power systems with a large share of wind *** deterministic spinning reserve requirement is supplemented by an adjustable fraction of the expected shortfall from the supply of wind electric generators(WEGs),computed using the stochastic feature of wind and loosely represented in the security constraint with *** optimization tool commits and dispatches generating units while simultaneously determining the geographical procurement of the required spinning reserve as well as load-following ramping reserve,by mixed integer quadratic programming(MIQP).Case studies are used to investigate various effects of grid integration on reducing the overall operation costs associated with more wind power in the system.

关键词： Flexible power system Reliability of supply Wind generation Expected energy not served(EENS) Value of lost load

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

大型太阳能抽水智能灌溉系统的设计与建模

大型太阳能抽水智能灌溉系统的设计与建模

作者： bonaventure Nzibonera 华北电力大学(北京)

学位级别：硕士

光伏(PV)技术迅速改善了农业灌溉领域,大部分在偏远和沙漠地区;卢旺达政府的目标是从发展中国家转向以农业生产为基础的中等收入国家。卢旺达80%以上的人口以农业为生。因此,本研究项目主要侧重于卢旺达东部地区干旱气候背景下的大型太... 详细信息

光伏(PV)技术迅速改善了农业灌溉领域,大部分在偏远和沙漠地区;卢旺达政府的目标是从发展中国家转向以农业生产为基础的中等收入国家。卢旺达80%以上的人口以农业为生。因此,本研究项目主要侧重于卢旺达东部地区干旱气候背景下的大型太阳能智能灌溉系统的设计和建模。长期月平均每日太阳全球辐照度在5月的4.8kwh/m/day至7月的5.8kwh/m/day之间。因此,光伏地理信息系统(PVGIS)估计选址区域日平均太阳辐照度为5.2kwh/m/day,显示出太阳能在智能灌溉方面的良好发展潜力。该论文基于MATLAB/Simulink进行系统建模,使用基于MPPT方法的增量电导进行仿真分析,以便在PWM系统中面板电压和电池应匹配。分析结果表明,该系统可向太阳能水泵输送100kw的电量,以每天4小时540m3的水量对玉米田进行智能灌溉,既高效又经济可行。采用太阳能抽水系统是持久保持偏远干旱地区农村社区可持续发展的重要手段。

关键词：光伏阵列 MPPT 太阳能光伏组件 DC-DC降压-升压转换器 VSC

Neurovascular ageing:transcriptomic readout and implications on therapeutic targeting in Alzheimer’s disease

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2021年第12期16卷 2411-2412页

作者： Zhongqi Li bonaventure Ip Vincent C.T.Mok Ho Ko Division of Neurology Department of Medicine and TherapeuticsThe Chinese University of Hong KongHong Kong Special Administrative RegionChina Li Ka Shing Institute of Health Sciences The Chinese University of Hong KongHong Kong Special Administrative RegionChina(Li ZKo H)Margaret K.L.Cheung Research Centre for Management of ParkinsonismThe Chinese University of Hong KongHong Kong Special Administrative RegionChina Chow Yuk Ho Technology Centre for Innovative Medicine The Chinese University of Hong KongHong Kong Special Administrative RegionChina Gerald Choa Neuroscience Centre School of Biomedical SciencesDepartment of PsychiatryPeter Hung Pain Research InstituteFaculty of MedicineThe Chinese University of Hong KongHong Kong Special Administrative RegionChina

Ageing is one of the greatest risk factors for neurodegenerative *** the complex biological changes in ageing increase the brain’s susceptibility to neurodegeneration remains incompletely *** into neurodegenerative disorders has shifted from a neuron-centric approach,to the contributing roles of age-related neurovascular and glial cell dysfunction.

关键词： incomplete susceptibility ageing

Thermal Properties of Earth Bricks Stabilised with Cement and Sawdust Residue Using the Asymmetrical Hot-Plane Method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2023年第11期13卷 1910-1934页

作者： Gabin Alex Nouemssi Guy Edgar Ntamack Martin Ndibi Mbozo’O bonaventure Djeumako Ecole Nationale Supérieure des Sciences Agros Industrielles Laboratoire de Mécanique Matériaux et Photonique University of Ngaoundéré Ngaoundéré Cameroon Département de Physique/EGCIM Faculté des Sciences et Physique Université de Ngaoundéré Ngaoundéré Cameroon Ecole Nationale Supérieure des Sciences Agros Industrielles Département de Génie Mécanique et Productique University of Ngaoundéré Ngaoundéré Cameroon

This paper presents an experimental study of the characterisation of local materials used in the construction and thermal insulation of buildings. These materials are compressed earth bricks stabilised with cement and sawdust. The thermal conductivity, diffusivity, effusivity, and specific heat of earth-based materials containing cement or sawdust have been determined. The results show that the blocks with earth + sawdust are better thermal insulators than the blocks with simple earth. We observe an improvement in thermal efficiency depending on the presence of sawdust or cement stabilisers. For cement stabilisation, the thermal conductivity increases (λ: 1.04 to 1.36 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 9.82 × 10-7 m2·s-1), and the effusivity decreases (1404 - 1096 J·m-2·K-1·s-1/2). For sawdust stabilisation, the thermal conductivity decreases (λ: 1.04 to 0.64 W·m-1·K-1), the diffusivity increases (from 4.32 × 10-7 to 5.9 × 10-7 m2·s-1), and the effusivity decreases (1404 - 906 J·m-2·K-1·s-1/2). Improving the structural and thermal efficiency of BTC via stabilisation with derived binders or cement is beneficial for the load-bearing capacity and thermal performance of buildings.

关键词： Clay Brick West Cameroon Thermal Conductivity Asymmetric Hot Surface Thermal Properties

Spatio-Temporal Dynamics of the Noun Floodplain (Cameroon) Using Remote Sensing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2022年第10期10卷 66-82页

作者： Junie Albine Atangana Kenfack Harold Gwet bonaventure Olivier Souley Rufis Fregue Tagne Tiegam Paul Tchawa Environment and Risk Dynamics Laboratory University of Yaounde I Yaoundé Cameroon Surface Formation Geophysics Laboratory University of Yaounde I Yaoundé Cameroon National School of Administration and Magistracy Yaounde Cameroon University of Dschang Dschang Cameroun

In Cameroon, the pressure on wetlands appears to be increasing, leading to desertification and land degradation. This study aims to characterize the spatial and temporal dynamics of land cover in the Noun floodplain in Cameroon using multi-date satellite data. To achieve this, the methodology consisted in using remote sensing and geographical information’s systems techniques to identify spatial units and detect changes over a 22-year period (1999 to 2021). The land cover maps were produced from an unsupervised classification with maximum likelihood. The results identified eight classes: herbaceous savannahs with shrubs, forest galleries, fields and plantations, herbaceous tan, young fallows, mineralized and built-up soils, bare soils and surface waters. It appears that in 1999, the landscape was dominated by natural vegetation (72.6%) located from north to south of the Noun plain. However, since 2004, the landscape has been dominated by agricultural areas (56.8%). Natural formations have been progressively reduced in space over time. The evolution of the Noun floodplain landscape reveals that 14.3% of the space has remained stable. These are fields and plantations, young fallows, mineralized soils and surface water. This space has not migrated to other classes. While about 73.9% of the area has moved to higher classes, of which 35.6% to herbaceous tans and 26% to fields and plantations. On the other hand, 72.6% of the area (herbaceous savannahs and forests gallery) has been heavily degraded. These results show that the landscape of the Noun floodplain is marked by a progressive agricultural extension, which would be at the origin of the land degradation. Therefore they alert the different actors in the territory on the level of advanced land degradation and suggest sustainable land management on a local scale.

关键词： Cameroon Land Use Land Degradation Remote Sensing Sustainable Land Management

Anticonvulsant, Sedative and Antidepressant Effects of Aqueous Extract of Costus afer Stems in Mice

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Biosciences and Medicines 2022年第12期10卷 22-31页

作者： Bassoueka D’Avila Judicaël Peneme bonaventure Max Lazard Ondele Radar Ahoudi Jered Abena Ange Antoine Laboratory of Pharmacodynamics and Experimental Physiopathology (L2PE) Faculty of Sciences and Techniques Marien Ngouabi University Brazzaville Republic of the Congo Biochemistry and Pharmacology Laboratory Faculty of Health Sciences Marien Ngouabi University Brazzaville Republic of the Congo

Epilepsy is a disorder in the nervous system which often causes a loss of consciousness. Traditional treatments are quiet a component of health care system in various populations in spite of the fact that well-established options are available. Most plants are used to treat epilepsy or those which have been verified for anticonvulsant activity were reported. Then, Costus afer is a plant of the Congolese flora used in traditional medicine for its many virtues. Therefore, the anticonvulsant activity of Costus afer was assessed with the strychnine convulsion induction test. Two tests were used for sedative activity such as the barbiturate sleep induction test and motor activity and finally the forced swimming test was also used to assess antidepressant activity. The results showed that the aqueous extract of Costus afer stems had no effects on strychnine-induced seizures at doses of 250 mg/kg and 500 mg/kg compared to the control group. However, the extract of Costus afer stems caused a very significant decrease in motricity at a dose of 500 mg/kg, showing a decrease in the onset time and a very significant increase in sleep duration like the reference molecule such as Diazepam. The aqueous extract of Costus afer stems also caused a decrease in immobility time in mice at a dose of 500 mg/kg.

关键词： Epilepsy Sedative Traditional Medicine Antidepressant Anticonvulsant

Elucidation of the Probable Ovarian-Dependent Mechanism of the Estrogenic Effects of Buccholzia coriacea and Progesterone Effects of Cogniauxia pololeana in the Rat

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2022年第7期12卷 1284-1295页

作者： bonaventure Max Lazare Peneme Arnaud Wilfrid Etou Ossibi Hermann Akassa Radard Ondélé Ange Antoine Abena Laboratory of Biochemistry and Pharmacology Faculty of health Sciences Marien Ngouabi University Brazzaville Republic of the Congo

The present study was carried out with the objective of evaluating, in castrated rats, the utero trophic, hormonal and biochemical activities of aqueous extracts of Buchholzia coriacea (BC) and Cogniauxia podolaena (CP) leaves. Each extract administered at the dose of 600 mg/Kg in castrated rats did not cause a significant change in the fresh weight/dry weight ratio of the uterus compared to castrated rats given distilled water. However, those receiving 17-β-estradiol as a reference product showed a significant (p < 0.5) increase in this ratio. These results indicate the absence of uterotrophic effects of both extracts in the ovariectomized rat compared with the effects of 17-β estradiol. In addition, the extracts did not cause significant changes in estrogen or progesterone levels in treated rats, as observed with 17-β-estradiol. In addition, the determination of protein and total cholesterol in the uterus of castrated rats treated with each extract did not show significant variation from controls. At the time, castrated rats treated with 17-β-estradiol showed a significant increase (p < 0.5) in uterine protein level and a significant decrease (p < 0.5) in total cholesterol level. Only the blood protein level was significantly increased in the castrated rats that received the extracts. These results suggest that the respective estrogenic and progesterone effects of the extracts of the two plants may be ovarian-dependent, these plants would not contain phytohormones.

关键词： Castrated Rat Cogniauxia podolaena Buchholzia coriacea Ovary-Dependent

Olive fruits infested with olive fly larvae respond with an ethylene burst and the emission of specific volatiles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2016年第4期58卷 413-425页

作者： Fiammetta Alagna Mario Kallenbach Andrea Pompa Francesca De Marchis Rosa Rao Ian T.Baldwin Gustavo bonaventure Luciana Baldoni CNR-Institute of Biosciences and Bioresources(IBBR) Perugia 06128Italy Department of Molecular Ecology Max Planck Institute of Chemical EcologyJena 07745Germany Department of Agronomy University of Naples"Federico II"80055 PorticiItaly

Olive fly（Bactrocera oleae R.） is the most harmful insect pest of olive（Olea europaea L.） which strongly affects fruits and oil production. Despite the expanding economic importance of olive cultivation, up to now, only limited information on plant responses to B. oleae is available. Here,we demonstrate that olive fruits respond to B. oleae attack by producing changes in an array of different defensive compounds including phytohormones, volatile organic compounds（VOCs）, and defense proteins. Bactrocera oleaeinfested fruits induced a strong ethylene burst and transcript levels of several putative ethylene-responsive transcription factors became significantly upregulated. Moreover, infested fruits induced significant changes in the levels of 12-oxophytodienoic acid and C12 derivatives of the hydroperoxide lyase. The emission of VOCs was also changed quantitatively and qualitatively in insect-damaged fruits, indicating that *** larval feeding can specifically affect the volatile blend offruits. Finally, we show that larval infestation maintained high levels of trypsin protease inhibitors in ripe fruits, probably by affecting post-transcriptional mechanisms. Our results provide novel and important information to understand the response of the olive fruit to B. oleae attack; information that can shed light onto potential new strategies to combat this pest.

关键词： Bactrocera oleae biotic stress Olea europaea phytohormones plant defense volatile organic compounds