A new model for curbing filtrate loss in dynamic application of nano-treated aqueous mud systems

Okoro, Emmanuel E.,Oladejo, Bukola R.,Sanni, Samuel E.,Obomanu, Tamunotonjo,Ibe, Amarachukwu A.,Orodu, Oyinkepreye D.,Olawole, Olukunle C. Techno-Press 2020 Advances in nano research Vol.9 No.1

Filter cake formation during rotary drilling operation is an unavoidable scenario, hence there is need for constant improvement in the approaches used in monitoring the cake thickness growth in order to prevent drill-string sticking. This study proposes an improved model that predicts the growth of mud cake thickness overtime with the consideration of the addition of nanoparticles in the formulated drilling fluid system. Ferric oxide, titanium dioxide and copper oxide nanoparticles were used in varying amounts (2 g, 4 g and 6 g), and filtration data were obtained from the HPHT filtration test. The filter cakes formed were further analyzed with scanning electron microscope to obtain the morphological characteristics. The data obtained was used to validate the new filtrate loss model. This model specifically presents the concept of time variation in filter cake formation as against the previous works of constant and definite time. Regression coefficient which is a statistical measure was used to validate the new model and the predicted results were compared with the API model. The new model showed R² values of 99.9%, and the predictions from the proposed filtration model can be said to be more closely related to the experimental data than that predicted from the API model from the SSE and RMSE results.

Women in the Igbo Culture: Extrapolations from Nsukka, South-Eastern Nigeria

Martins N. Okoro 숙명여자대학교 아시아여성연구원 2022 Asian Women Vol.38 No.1

The study documents all the key aspects through which the cultural representation of the Nsukka town women is constructed. It seeks to investigate women’s involvement and participation in the cultural enactment of festivals, title-taking ceremonies, burials and funerals, marriage ceremonies, postpartum care, and conflict resolution, relying on materials from literature, ethnographic data, studies involving participant observation, and interview sessions with natives possessing a sufficient knowledge of culture and tradition. Data collected were examined using historical descriptive and analytical methods and the study is anchored in Jones Lewis’s theory of feminism which, among other criticisms, questions how much of our culture is based on patriarchal assumptions. The study found that even though women are subjugated in certain aspects of life, their involvement and participation in the enactments of cultural events and conflict management in Nsukka town give them some sense of belonging and that, without their involvement, such cultural and traditional events would not take place and their essence would be lost. These counter claim that men are often considered the drivers of cultural activities and as such belong to the public domain while women are confined purely to private life and domestic activities. The study is helpful in understanding the implications of women’s involvement and participation in the enactments of culture and tradition in Nsukka town.

Association between serum vitamin D status and uterine leiomyomas: a case-control study

Chukwuemeka Chukwubuikem Okoro,Okechukwu Christian Ikpeze,George Uchenna Eleje,Gerald Okanandu Udigwe,Chukwuemeka Okwudili Ezeama,Joseph Odirichukwu Ugboaja,Chukwunonso Isaiah Enechukwu,Osita Samuel U 대한산부인과학회 2024 Obstetrics & Gynecology Science Vol.67 No.1

Objective Uterine leiomyoma is a common gynecological condition that negatively affects women’s quality of life. Vitamin D plays an important role in tumor development and progression. However, clinical studies comparing serum vitamin D levels between women with and without uterine leiomyomas are limited and inconclusive. This study aimed to compare serum vitamin D levels in women with and without uterine leiomyomas. Methods This hospital-based case-control study included 150 women who visited a gynecological clinic. The cases included 75 women with uterine leiomyoma, whereas the controls included 75 age-and parity-matched participants without uterine leiomyoma. Serum vitamin D levels were measured in each participant and volumes of the uterine leiomyomas were determined using the water displacement method following myomectomy. The statistical significance was inferred at P<0.05. Results The mean serum vitamin D level was 15.26±4.96 ng/mL and 22.45±6.93 ng/mL for the case and control groups, respectively. The difference was statistically significant (t-value -7.302 and P<0.001). Within the fibroid group, nine (12.0%), 49 (65.33%), and 17 (22.67%) participants had vitamin D deficiency, insufficiency, and sufficiency, respectively; and in the control group, two (2.67%), 24 (45.33%), and 39 (52.0%) participants had vitamin D deficiency, insufficiency, and sufficiency, respectively. There was significant negative correlation between the fibroid volume and the serum vitamin D level (r=-0.591, P<0.001). Conclusion Women with uterine leiomyoma had lower vitamin D levels than women in the control group. Lower vitamin D levels were associated with larger fibroid masses. Therefore, vitamin D supplementation may reduce fibroid growth and development.

Microstructural Evolution and Mechanical Properties of Multiwall Carbon Nanotubes Reinforced Titanium-Based Nanocomposites Developed by Spark Plasma Sintering

Avwerosuoghene Moses Okoro,Ronald Machaka,Senzeni Sipho Lephuthing,Mary Ajimegoh Awotunde,Peter Apata Olubambi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

In this study, the role of multiwall carbon nanotubes (MWCNT) on the microstructural evolution and mechanical propertiesof Ti6Al4V-based composites was investigated. This was conducted by dispersing different concentrations (0.5, 1.0 and1.5 wt%) of MWCNT into the Ti6Al4V matrix using shift-speed ball milling technique. Thereafter, the Ti6Al4V and thenanocomposites were consolidated via the spark plasma sintering technique. Various characterization techniques; scanningelectron microscopy (SEM), transmission electron microscopy (TEM) and light microscopy were conducted to understandthe microstructural evolution of the samples after the dispersion and sintering process. Subsequently, micromechanical andnanoindentation was carried out to reveal the mechanical properties of the fabricated samples. The morphological examinationusing SEM and TEM revealed the dispersibility of MWCNT dispersed within the Ti6Al4V matrix. Besides, the selectedarea diffraction and the fast Fourier Transform pattern demonstrated that the increase in concentration of the MWCNTexposed the nanotubes to adverse stresses during the dispersion process. Furthermore, the incorporation and increase inconcentration of the MWCNT in the titanium alloy resulted in microstructural and phase changes, which translate to tremendousimprovements in microhardness, nanohardness and elastic modulus up to 46.9%, 150.8%, and 169.5% respectively.

Streptomyces deserti sp. nov., isolated from hyper-arid Atacama Desert soil.

Santhanam, Rakesh,Okoro, Chinyere K,Rong, Xiaoying,Huang, Ying,Bull, Alan T,Andrews, Barbara A,Asenjo, Juan A,Weon, Hang-Yeon,Goodfellow, Michael N.V. Swets en Zeitlinger 2012 Antonie van Leeuwenhoek Vol.101 No.3

<P>The taxonomic position of a Streptomyces strain isolated from a hyper-arid desert soil was established using a polyphasic approach. The organism had chemical and morphological properties typical of the genus Streptomyces and formed a phyletic line at the periphery of the Streptomyces coeruleorubidus subcluster in the 16S rRNA gene tree. DNA:DNA relatedness values between the isolate and its nearest phylogenetic neighbours, Streptomyces lomondensis NRRL 3252(T) and Streptomyces lusitanus NRRL B-12501(T) were 42.5 (±0.48)% and 25.0 (±1.78)%, respectively. The isolate was readily distinguished from these organisms using a combination of morphological and phenotypic properties. On the basis of these results, it is proposed that isolate C63(T) (CGMCC 4.6997(T),??=??KACC 15425(T)) be classified as the type strain of Streptomyces deserti sp. nov.</P>

Streptomyces atacamensis sp. nov., isolated from an extreme hyper-arid soil of the Atacama Desert, Chile

Santhanam, Rakesh,Okoro, Chinyere K.,Rong, Xiaoying,Huang, Ying,Bull, Alan T.,Weon, Hang-Yeon,Andrews, Barbara A.,Asenjo, Juan A.,Goodfellow, Michael Microbiology Society 2012 International journal of systematic and evolutiona Vol.62 No.11

<P>The taxonomic position of a <I>Streptomyces</I> strain isolated from an extreme hyper-arid soil sample collected from the Atacama Desert was determined using a polyphasic approach. The strain, isolate C60<SUP>T</SUP>, had chemical and morphological features typical of members of the genus <I>Streptomyces</I> and formed a distinct phyletic line in the <I>Streptomyces</I> 16S rRNA gene tree, together with the type strain of <I>Streptomyces radiopugnans</I><I>.</I> The two strains were distinguished readily using a combination of phenotypic properties and by a DNA-DNA relatedness value of 23.17 (±0.95) %. On the basis of these genotypic and phenotypic data, it is proposed that isolate C60<SUP>T</SUP> ( = CGMCC 4.7018<SUP>T</SUP> = KACC 15492<SUP>T</SUP>) be classified in the genus <I>Streptomyces</I> as <I>Streptomyces atacamensis</I> sp. nov.</P>

Rain Attenuation Prediction at Different Time Percentages for Ku, K, and Ka Bands Satellite Communication Systems over Nigeria

Orji Prince Orji,Obiegbuna Dominic Chukwuebuka,Okoro Eucharia Chidinma,Ugonabo Obiageli Josephine,Okezuonu Patrick Chinedu,Iyida Evaristus Uzochukwu,Ugwu Chukwuebuka Jude,Menteso Firew Meka,Ikechukwu 한국우주과학회 2024 Journal of Astronomy and Space Sciences Vol.41 No.1

This paper evaluates the influence of rainfall on propagated signal at different time exceedance percentages of an average year, over the climate zones of the country. Specifically, it demonstrates critical and non critical signal fade or signal outage time exceedance (0.001% to 1%) for Ku, K, and Ka-band systems in an average year. The study was carried out using meteorological data made available by the Nigerian Meteorological Agency (NiMet) over a period of 10 years (2009–2018). The four climate zones in the country were represented by five (5) locations; Maidugiri (warm desert climate), Sokoto (tropical dry climate), Port Harcourt (tropical monsoon climate), Abuja and Enugu (tropical savanna climate). The parameters were simulated into the International Telecommunications Union Recommended (ITU-R) models for rain attenuation over the tropics and results presented using MatLab and Origin Lab. Results of Ku band propagations showed that only locations in the tropical savanna and tropical monsoon climates experienced total signal outage for time percentage exceedance equal to or below 0.01% for both horizontal and vertical polarizations. At K band propagations, the five locations showed to have experienced signal outage at time exceedance equal to and below 0.01%, almost same was recorded for the Ka-band propagation. It was also observed that horizontal and vertical polarization of signal had slightly different rain attenuation values for the studied bands at the five locations, with horizontal polarization having higher values than vertical polarization.

Heterogeneous Catalytic Gasification of Biomass to Biofuels and Bioproducts: A Review

Sanni Samuel Eshorame,Oni Babalola Aisosa,Okoro Emeka Emmanuel 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.4

Biomass gasifi cation is one of the most viable approaches for exploiting biomass. It systemically employs several agents in stimulating the desired reactions that lead to the conversion of biomass feed stocks to fuels/other products. Owing to the biodiversity of the products of biomass gasifi cation, they are fast becoming substitutes for fossil-based products/fuels. In order to ensure optimal production of potential bioproducts, the process conditions of a gasifi cation process have to be essentially controlled within the ambience of high throughput. Based on existing literature, biomass gasifi cation to fuels is not essentially new; however, till date, none of the existing works seeks to unveil the role of heterogeneous catalysis in biomass gasifi cation toward ensuring high bioproducts yield. Heterogeneous catalysis seems to play a crucial role in biomass gasifi cation owing to the fact that catalyst involvement in gasifi cation processes helps to lower the activation energy of specifi c reactions; hence, under thermal infl uence, the catalysts tend to hasten such reactions for the desired conversions. Furthermore, it is also pertinent to take into consideration viable approaches for extending or maintaining the service life of the catalyst employed by deploying apt modalities that abate catalyst poisoning (aging, deactivation and fouling); this paper seeks to cover such challenges.

Rainfall Harvesting as an Alternative Water Supply in Water Stressed Communities in Aguata-Awka Area of Southeastern Nigeria

Okpoko, Ephraim,Egboka, Boniface,Anike, Luke,Okoro, Elizabeth Korean Society of Environmental Engineers 2013 Environmental Engineering Research Vol.17 No.1

Alternative sources of water are sought in some water stressed communities in the study area. The study focuses on the Aguata-Awka area of southeastern Nigeria. Aquifers occur at great depths, and surface waters may be far from homesteads. The scarcity of water has necessitated the people to adopt various local technologies for harvesting rainfall. The local technology includes collecting rainwater from roofs and channeling the water into large underground tanks, shallow wells and surface reservoirs. Large concrete tanks of $6m{\times}6m{\times}4m$ dimensions are often built underground and can store $144m^3$ of water. Surface reservoirs built on 4 m concrete pillar supports having dimensions of $10m{\times}10m{\times}4m$ and have a storage capacity of $400m^3$. Water samples were collected at 3 different locations of Agulu, Ekwulobia, and Awka and were analyzed for their physical, chemical, and bacteriological parameters. Results indicate a range of values for pH, 5.9 to 7.1; turbidity, 0.9 to 2.7; total dissolved solids, 80 to 170 mg/L; total hardness, 4.5 to 6.4 mg/L; magnesium, 1.2 to 1.4 mg/L; bicarbonate, 19.4 to 83.6 mg/L; and sulfate, 3.6 to 6.4 mg/L. Bacteriological analysis results were negative for fecal and total coliform counts. All parameters, with the exception of pH where aluminum and galvanized iron roofs are used for collection, fall within the recommended guidelines for drinking water quality of the World Health Organization, and the Standard Organization of Nigeria, new Nigerian standards for drinking water quality. Magnesium is above the maximum permitted level for consumer acceptability of the Nigerian standards for drinking water quality. The water can be classified as fresh moderately hard and soft. The water can be described as a calcium and bicarbonate type.

Rainfall Harvesting as an Alternative Water Supply in Water Stressed Communities in Aguata-Awka Area of Southeastern Nigeria

Ephraim Okpoko,Boniface Egboka,Luke Anike,Elizabeth Okoro 대한환경공학회 2013 Environmental Engineering Research Vol.18 No.2

Alternative sources of water are sought in some water stressed communities in the study area. The study focuses on the Aguata-Awka area of southeastern Nigeria. Aquifers occur at great depths, and surface waters may be far from homesteads. The scarcity of water has necessitated the people to adopt various local technologies for harvesting rainfall. The local technology includes collecting rainwater from roofs and channeling the water into large underground tanks, shallow wells and surface reservoirs. Large concrete tanks of 6 m × 6 m × 4 m dimensions are often built underground and can store 144 m3 of water. Surface reservoirs built on 4 m concrete pillar supports having dimensions of 10 m × 10 m × 4 m and have a storage capacity of 400 m3. Water samples were collected at 3 different locations of Agulu, Ekwulobia, and Awka and were analyzed for their physical, chemical, and bacteriological parameters. Results indicate a range of values for pH, 5.9 to 7.1; turbidity, 0.9 to 2.7; total dissolved solids, 80 to 170 mg/L; total hardness, 4.5 to 6.4 mg/L; magnesium, 1.2 to 1.4 mg/L; bicarbonate, 19.4 to 83.6 mg/L; and sulfate, 3.6 to 6.4 mg/L. Bacteriological analysis results were negative for fecal and total coliform counts. All parameters, with the exception of pH where aluminum and galvanized iron roofs are used for collection, fall within the recommended guidelines for drinking water quality of the World Health Organization, and the Standard Organization of Nigeria, new Nigerian standards for drinking water quality. Magnesium is above the maximum permitted level for consumer acceptability of the Nigerian standards for drinking water quality. The water can be classified as fresh moderately hard and soft. The water can be described as a calcium and bicarbonate type.