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Effect of Calcination Condition on Thermal Activation of Ibere Clay and Dissolution of Alumina

International Journal of Nonferrous Metallurgy 2019年第2期8卷 9-24页

作者： Udochukwu Mark Charles Nwachukwu Anyakwo okechukwu onyebuchi onyemaobi Chijioke Samson Nwobodo Department of Materials and Metallurgical Engineering Federal University of Technology Owerri Nigeria

Bauxite deposits for production of alumina are lacking in Nigeria and there is an aluminium smelter plant in the country which requires alumina for its operation. Development of alternative alumina resource using clays that are abundant in the country is the focus of this paper. The thermal activation of Ibere clay from southeastern Nigeria for optimal leaching of alumina was investigated. The clay assayed 28.52% Al2O3 and 51.6% SiO2, comprising mainly kaolinite mineral and quartz or free silica. The alumina locked up in the clay structure was rendered acid-soluble by thermal activation which transformed the clay from its crystalline nature to an amorphous, anhydrous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500°C, 600°C, 700°C, 800°C, and 900°C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000°C (holding for 60 minutes) were used in the control experiments. The result of leaching the clay calcines in 1 M hydrochloric acid solution at room temperature, showed that the clay calcines produced at 600°C (holding for 60 minutes) responded most to leaching. Samples calcined for 60 minutes also responded better than those held for 30 or 90 minutes. Based on activation energy studies, it was observed that calcines produced at 600°C (for 60 minutes) had both the highest leaching response (50.27% after 1 hour at leaching temperature of 100°C) and the lowest activation energy of 24.26 kJ/mol. It is concluded therefore that Ibere kaolinite clay should be best calcined for alumina dissolution by heating up to 600°C and holding for 60 minutes at that temperature. The clay deposit has potential for use as alternative resource for alumina production in Nigeria where bauxite is scarce.

关键词： Ibere Clay Bauxite Kaolinite Alumina Calcination Thermal Activation Leaching

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Determination of the Calcination Procedure Required to Activate Edda Clay for Optimal Leaching of Alumina

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Journal of Minerals and Materials Characterization and Engineering 2019年第2期7卷 49-63页

Nigeria is the highest consumer of aluminium in Africa but lacks bauxite deposits. The replacement of bauxite alumina with other alumina bearing resources (clays in particular) has been proposed. The present study investigated the thermal treatment required to activate Edda clay from southeastern Nigeria for optimal leaching of alumina. The clay is composed mainly of kaolinite and quartz, assaying 24.65% Al2O3 and 52.81% SiO2. Thermal activation of the clay prior to leaching transformed the crystalline kaolinite mineral to an amorphous phase (metakaolinite) in which the alumina became soluble. Clay samples passing 300 μm sieve were calcined at temperatures of 500°C, 600°C, 700°C, 800°C, and 900°C at holding times of 30, 60, and 90 minutes in each case. The uncalcined clay and sample heated at 1000°C (for 60 minutes) were used in the control experiments. Leaching of alumina from the resulting clay calcines was done in 1 M hydrochloric acid solution at room temperature using a solid/liquid ratio of 0.02 g/ml and shaking speed of 100 rpm. The solubility data based on the percentage of Al ions taken into leach solution showed that the sample calcined at 700°C (for 60 minutes) responded to leaching better than other samples. Samples calcined for 60 minutes at all temperatures studied were found to respond more than those held for 30 or 90 minutes. Studies on the activation energy of leaching revealed that calcines produced at 700°C (for 60 minutes) had both the highest leaching response (49.96% after 1 hour at leaching temperature of 100°C) and the lowest activation energy of 24.47 kJ/mol. It is concluded therefore that Edda kaolinite clay should be thermally activated for alumina yield by heating up to 700°C and holding for 60 minutes. The clay deposit is therefore a potential alternative resource for alumina production.

关键词： Edda Clay Bauxite Kaolinite Alumina Calcination Thermal Activation Leaching

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Conditions for Thermal Activation of Ngwo Clay as an Alternative Resource for Alumina

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Natural Resources 2019年第1期10卷 1-15页

The thermal activation of Ngwo clay from southeastern Nigeria for optimal leaching of alumina was investigated. The clay assayed 24.63% Al2O3 and 52.15% SiO2, comprising mainly kaolinite mineral and free silica or quartz. The alumina locked up in the clay structure was rendered acid-soluble by thermal activation which transformed the clay from its crystalline nature to an amorphous, porous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500°C, 600°C, 700°C, 800°C, and 900°C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000°C (holding for 60 minutes) were used in the control experiments. After leaching the resulting clay calcines in 1 M hydrochloric acid solution at room temperature, it was observed that the clay calcines produced at 700°C (holding for 60 minutes) responded most to leaching. Samples calcined for 60 minutes also responded better than those held for 30 or 90 minutes. Based on activation energy studies, it was observed that calcines produced at 700°C (for 60 minutes) had both the highest leaching response (51.84%?after 1 hour at leaching temperature of 100°C) and the lowest activation energy of 25.03 kJ/mol. It is concluded therefore that Ngwo kaolinite clay should?be best calcined for alumina dissolution by heating up to 700°C and holding for 60 minutes at that temperature. The clay deposit has potential for use as alternative resource for alumina production in Nigeria where bauxite is scarce.

关键词： Ngwo Clay Bauxite Kaolinite Alumina Calcination Thermal Activation Leaching

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Evaluation of Hydrocarbon Potential Using AVO Analysis in the FORMAT Field, Niger Delta Basin, Nigeria

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Open Journal of Geology 2024年第3期14卷 403-430页

作者： Charles Chibueze Ugbor onyebuchi Samuel Onyeabor Ifeanyi Celestine Ugwuoke Department of Geology University of Nigeria Nsukka Enugu State Nigeria

The study involved the evaluation of the hydrocarbon potential of FORMAT Field, coastal swamp depobelt Niger delta, Nigeria to obtain a more efficient reservoir characterization and fluid properties identification. Despite advances in seismic data interpretation using traditional 3D seismic data interpretation, obtaining adequate reservoir characteristics at the finest level had proved very challenging with often disappointing results. A method that integrates the amplitude variation with offfset (AVO) analysis is hereby proposed to better illuminate the reservoir. The Hampson Russell 10.3 was used to integrate and study the available seismic and well data. The reservoir of interest was delineated using the available suite of petrophysical data. This was marked by low gamma ray, high resistivity, and low acoustic impedance between a true subsea vertical depth (TVDss) range of 10,350 - 10,450 ft. The AVO fluid substitution yielded a decrease in the density values of pure gas (2.3 - 1.6 g/cc), pure oil (2.3 - 1.8 g/cc) while the Poisson pure brine increased (2.3 to 2.8 g/cc). Result from FORMAT 26 plots yielded a negative intercept and negative gradient at the top and a positive intercept and positive gradient at the Base which conforms to Class III AVO anomaly. FORMAT 30 plots yielded a negative intercept and positive gradient at the top and a positive intercept and negative gradient at the Base which conforms to class IV AVO anomaly. AVO attribute volume slices decreased in the Poisson ratio (0.96 to - 1.0) indicating that the reservoir contains hydrocarbon. The s-wave reflectivity and the product of the intercept and gradient further clarified that there was a Class 3 gas sand in the reservoir and the possibility of a Class 4 gas sand anomaly in that same reservoir.

关键词： AVO Analysis Hydrocarbon Potential Fluid Properties Reservoir Characterization Petrophysical Data Hampson Russel

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RUNX1通过调节SOX2转录促进食管鳞状细胞癌干性

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皖南医学院学报 2024年第4期43卷 316-321页

作者：黄滔尤琦 Ifeanyi Christian onyebuchi 朱少金皖南医学院第一附属医院弋矶山医院胸外科安徽芜湖241001

目的:探讨RUNT相关转录因子1(RUNX1)在食管鳞状细胞癌中的表达及其对细胞干性的影响。方法:从GEPIA数据库和GEO数据库(GSE111011)获取RUNX1的表达情况,使用TCGA数据库分析基因表达相关性。利用Western blot检测RUNX1、SOX2、OCT4、KLF4... 详细信息

目的:探讨RUNT相关转录因子1(RUNX1)在食管鳞状细胞癌中的表达及其对细胞干性的影响。方法:从GEPIA数据库和GEO数据库(GSE111011)获取RUNX1的表达情况,使用TCGA数据库分析基因表达相关性。利用Western blot检测RUNX1、SOX2、OCT4、KLF4和c-MYC蛋白表达情况。利用qRT-PCR技术检测CD271、CD44、CD54、SOX2和RUNX1的mRNA水平,双荧光素酶报告基因实验检测SOX2启动子活性。通过细胞成球培养和流式细胞术检测侧群细胞和CD271^(+)/CD44^(+)细胞的数量反映细胞干性。结果:GEPIA数据库、GEO数据库和Western blot结果均显示RUNX1在食管癌中高表达。在Eca-109细胞中敲低RUNX1后,抑制SOX2表达和细胞干性(P<0.01)。在KYSE-150细胞中过表达RUNX1后,促进SOX2表达和细胞干性增加(P<0.01)。在KYSE-150细胞中同时过表达RUNX1和敲低SOX2后,RUNX1促进的细胞干性增加被逆转(P<0.01)。双荧光素酶报告基因实验结果显示RUNX1促进SOX2启动子活性,在转录水平调节SOX2表达。结论:RUNX1在食管鳞状细胞癌中高表达,并通过在转录水平调节SOX2表达,从而促进细胞干性。

关键词： RUNT相关转录因子1 性别决定区Y框蛋白2 干性食管鳞状细胞癌

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Scaling up Nigeria’s Midwives Service Scheme and Reducing Inequality Gaps in Maternal Mortality

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Open Journal of Obstetrics and Gynecology 2017年第8期7卷 880-896页

作者： Emmanuel onyebuchi Onugha St. Camillus Catholic Hospital Uromi Nigeria

The Federal Government of Nigeria in December 2009 launched midwives service scheme to address the shortage of skilled healthcare workforce needed to drive the efforts at improving maternal and infant health, towards the attainment of MDGS 4 and 5. This was in response to the unrelenting increase in maternal mortality in Nigeria. This review explores the implementation of the scheme and the extent to which its set-goals are achieved vis-à-vis many challenges confronting it. The review first explores the ecologic perspective on maternal mortality to identify factors responsible for high mortality among Nigerian women and the inequality gaps in maternal mortality. The review identifies the need to scale up midwives service scheme to areas in dire health needs, identifies the need for health needs assessment, and recognizes community participation as an essential ingredient in ensuring the sustainability of midwives service scheme. Routine evaluation of midwives service scheme is identified as an important tool for assessing the effectiveness of the scheme in achieving its objectives towards improvement in maternal health and reduction in inequality gaps in maternal mortality. The review proposes multi-sectoral interventions in tackling inequality gaps in maternal mortality with strategic focus on addressing inequalities in health and social determinants of health.

关键词： Midwives Service Scheme Maternal Mortality Inequality Nigeria

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Assessment of the Spectral Decomposition Techniques in the Evaluation of Hydrocarbon Potential of “BOMS” Field, Coastal Swamp Niger Delta, Nigeria

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International Journal of Geosciences 2023年第7期14卷 655-676页

作者： Charles Chibueze Ugbor onyebuchi Samuel Onyeabor Department of Geology University of Nigeria Nsukka Nigeria

This study employs the different approaches of the spectral decomposition techniques to evaluate the hydrocarbon potential of the reservoir and analyse to determine the most efficient spectral decomposition technique with better resolution using the “BOMS” Field, coastal swamp depobelt Niger Delta, Nigeria. A good number of drilled wells have failed both in the Niger Delta Basin and other basins due to a poor understanding of the reservoir properties in advance of drilling and identifying the best approach will help to minimize this risk. Seismic and well logs data together with the Hampson Russel 10.3 software were used for the study. The target reservoirs were identified from the suite of well logs at the horizons with low gamma ray, high resistivity, and low acoustic impedance between TVD (ft) of 10,350 - 10,450 ft. The analysis of the amplitude spectrum of the seismic data revealed that the distortion of interest lies between 5 - 60 Hz. Seismic data were then spectrally decomposed into several frequencies such as low frequency (15 Hz), mid-frequency (31 Hz), and high frequency (46 Hz) where distortions were observed. Time- frequency slices of 15 Hz and 23 Hz provided clearer events (potential hydrocarbon sand) indicated by high amplitude envelope (2200 - 2400) and amplitude anomalies. While the amplitude dropped in the mid-frequency (31 Hz), the high amplitude envelope and the high energy completely disappeared in the high (46 Hz) time-frequency slice. A comparison of the Short- time Fourier transform and the Basic Pursuit algorithm revealed that the Basic Pursuit provided a better resolution of the reservoir characteristics than the former. The Red, Green and Blue (RGB) colour blending model indicated that the channel was consistent with the low-frequency section and amplitude anomaly.

关键词： Amplitude Hydrocarbon Evaluation Spectral Analysis Reservoir Sand Basic Pursuit Convolution

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Quadcopter Design for Payload Delivery

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Journal of Computer and Communications 2016年第10期4卷 1-12页

作者： Gordon Ononiwu Ondoma Onojo Oliver Ozioko onyebuchi Nosiri Department of Electrical/Electronic Engineering Federal University of Technology Owerri Nigeria

This paper presents the design and implementation of a quadcopter capable of payload delivery. A quadcopter is a unique unmanned aerial vehicle which has the capability of vertical take-off and landing. In this design, the quadcopter was controlled wirelessly from a ground control station using radio frequency. It was modeled mathematically considering its attitude and altitude, and a simulation carried out in MATLAB by designing a proportional Integral Derivative (PID) controller was applied to a mathematical model. The PID controller parameters were then applied to the real system. Finally, the output of the simulation and the prototype were compared both in the presence and absence of disturbances. The results showed that the quadcopter was stable and able to compensate for the external disturbances.

关键词： Quadcopter PID Controller Payload Delivery Unmanned Aerial Vehicle

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Effects of Reneging, Server Breakdowns and Vacation on a Batch Arrival Single Server Queueing System with Three Fluctuating Modes of Service

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Open Journal of Optimization 2020年第4期9卷 105-128页

作者： Samuel Ugochukwu Enogwe H. onyebuchi Obiora-Ilouno Department of Statistics Michael Okpara University of Agriculture Umudike Nigeria Department of Statistics Nnamdi Azikiwe University Awka Nigeria

This article examines the effects of reneging, server breakdown and server vacation on the various states of the batch arrivals queueing system with single server providing service to customers in three fluctuating modes. In this queueing system, any batch arrival joins the queue if the server is busy or on vacation or under repair. However, if the server is free, one customer from the arriving batch joins the service immediately while others join the queue. In case of server breakdown, the customer whose service is interrupted returns back to the head of the queue. As soon as the server has is repaired, the server attends to the customer in mode 1. For this queueing system, customers that are impatient due to breakdown and server vacation may renege (leave the queue without getting service). Due to fluctuating modes of service delivery, the system may provide service with complete or reduced efficiency. Consequently, we construct the mathematical model and derive the probability generating functions of the steady state probabilities of several states of the system including the steady state queue size distribution. Further, we discuss some particular cases of the proposed queueing model. We present numerical examples in order to demonstrate the effects of server vacation and reneging on the various states of the system. The study revealed that an increase in reneging and a decrease in server vacation results in a decrease in server utilization and an increase in server’s idle time provided rates of server breakdown and repair completion are constant. In addition, the probability of server vacation, the probability of system is under repair and the probabilities that the server provides service in three fluctuating modes decreases due to an increase in reneging and a decrease in vacation completion rates.

关键词： Queueing Reneging Server Vacation Server Breakdowns Fluctuating Modes of Service

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Farmers’perceptions on cultivation and the impacts of climate change on goods and services provided by Garcinia kola in Nigeria

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Ecological Processes 2018年第1期7卷 425-434页

作者： onyebuchi Patrick Agwu Adama Bakayoko Saka Oladunni Jimoh Porembski Stefan WASCAL Graduate Research Program on Climate Change and Biodiversity Universite´Felix Houphouet BoignyBP 165Abidjan 31Côte d’Ivoire Centre Suisse de Recherches Scientifiques en Côte d’Ivoire(CSRS) UniversitéNangui AbrogouaAbidjanCôte d’Ivoire Department of Social and Environmental Forestry University of IbadanIbadanNigeria Institute for Biodiversity Research University of RostockRostockGermany

Background:Garcinia kola is an indigenous multipurpose tree species commonly found in the tropical rain forest zone of West and Central *** economic,ecological,and socio-cultural benefits for people,they have potentials to improve the regional and local income generation to the farmers but the cultivation of the species is very limited in ***:The study investigated cultivation and farmers’perceptions on the impacts of climate change on goods and services provided by *** in *** questioners and interviews were *** data obtained was analyzed using descriptive and inferential statistic such as frequency,percentage,chi-square,and multinomial logit regressions with SPSS Version 20 and R software Version ***:The results show that farmers are presently not cultivating ***,and most of the available stands were inherited from *** farmers still believe it is only God that can make *** to germinate;however,information about the new improved methods of raising *** was not spread across farmers’*** 93%of these farmers were not aware of these new methods,and the only means they raise the species is by picking the wildlings that regenerate naturally close to mother tree and are rarely *** finding also shows that farmers are well aware of climate change and its impact on crop productivity is not clear to *** result shows that five explanatory variables(age,gender,marital status,education level,household size and primary occupation)are the main factors significantly influencing farmers’perception of climate change and the cultivation of the *** interview section,the farmers reported variability of Harmattan season influences fruit production of the species;according to them,increase in Harmattan season usually leads to increase in fruiting of ***:Based on our findings,all the 215 respondent interviewed agree that climatic variability influences the availabi

关键词： Garcinia kola Propagation Multipurpose species Farmers Climate change Harmattan season

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