bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Development of Technology Governance in the Well Area
Authors: Leite Julio Cesar Costa , Lopes Manoela Teixeira 
Published: October 2019

Abstract
The present paper describes the establishment and implementation of the technology governance in the well area at Petrobras, which includes R&D, qualification and homologation projects. Corporate standards delineated the technology governance to assure uniformity and impersonality. It comprises two main processes: (i) establishment of technical specifications; (ii) technology evaluation. The former includes the elaboration/review of technical specifications focused on functional, quality and reliability aspects and clearly defined normative requirements. The latter process begins with the presentation of the technology by the potential suppliers and evaluation of interest by the project areas. Subsequently, in accordance with the readiness level assigned to the technology, it may be allocated as a R&D, qualification or homologat ion project, addressing to the appropriate treatment and assuring celerity for the necessary analysis.
To operationalize the whole process, Petrobras created a department in well area responsible for structuring and leading processes related to the admission of new technologies to the company, linked with the already well established R&D process. Deliberative forums have been held with managers of all the technical areas involved allowing collegial decision. Prioritized projects have been conducted by multidisciplinary working groups, including representatives from project and operation team, contract department, and also well experts. All technology process deliveries are reported by means of standard documents and are recorded in corporate system ensuring traceability and technical memory preservation. Nowadays, all the processes are well established and running for over 2 years with good feedback from stakeholders. It is worth mentioning the improvements in communication flow between and within departments and teams, better definition of roles and responsibilities reducing interface issues and easy availability of information that may be accessed for all parties involved with the projects. Additionally, there is a continuous improvement for system solutions assuring input, maintain, control and consult the whole information shared throughout the process.
The method adopted based on technology readiness level for new equipment/material/service assessment is aligned to good practices from other segments, such as aerospace industry. Moreover, technical specification focused on functional, quality and reliability requirements and system solutions for quick information availability complies with IOGP recommendations, ISO standards and with an increasingly restrictive regulation scenario especially after the lessons learned post-Macondo.
Efforts and Experiences, Developing Deepwater Projects in Brazil
Authors: Melo Toneto de Ricardo , Valença J G M Claudio 
Published: October 2019

Petrobras, as the largest operator in ultra-deep waters in South America, has been using a field development concept that has proved to be winner since 2010. This concept is well suited for fields with high productivity wells, which produce more than 20,000 barrels of oil per day. In the market, this concept is known as "satellite wells".
In this scenario, Petrobras has benefited from its strategy of standardizing subsea equipment, including Wet Christmas Trees (WCT), Flexible Pipes, Umbilicals and Subsea Manifolds. However, since the downturn of 2014, Petrobras has been struggling to simplify its own specifications, looking for the most attractive CAPEX solutions in the market, allowing suppliers to use their own knowledge and experiences to propose low cost solutions, meeting projects requirements.
From 2015 onwards, Petrobras has been working with the suppliers, with the Early Engagement initiative, aiming that the integration synergies, existing assets and the experience of these suppliers, could bring to the projects, the benefits of CAPEX reduction, and allowing the advancement and approval of these projects internally in the company.
Technological development programs to allow the use of flexible pipes that are resistant to contaminants such as CO2 and H2S, new CRA materials to be applied to rigid flowlines and low-cost riser configurations, have been pursued by Petrobras in order to enable the implementation of ultra-deep water projects.
Assessment of Antioxidant Status and Lipid Peroxidation in Pre-Eclampsia
Authors: Manafa Patrick O. , Onyenekwe Charles C. , Igwe Anselem C. , Mbachu Nancy A. , Chukwuma George O. , Chukwuanukwu Rebecca C. , Manafa Vera I. , Nwene Kenneth E. , Ibeh Nancy C. 
Published: October 2019

Aim: To assess the role of antioxidants and lipid peroxidation in the pathogenesis of pre-eclampsia.
Study Design: This is a case-control study designed to evaluate the levels of malondialdehyde and total antioxidant capacity with glutathione peroxidase and superoxide dismutase activities in pre-eclamptic. One hundred (100) participants were randomly selected to include fifty pre-eclamptic (test), twenty-five (25) healthy pregnant normotensive women (control A) and twenty-five healthy non-pregnant normotensive women (control B).
Place and Duration of Study: This study was carried out at the Holy Rosary Hospital waterside, Onitsha, Anambra state. Nigeria. The study lasted for 13 months.
Methodology: One hundred women (50 pre-eclamptic, 25 pregnant normotensives and 25 non-pregnant normotensives) aged 25-40 years were recruited for this study. Blood samples were collected from the participants for the estimation of total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities using spectrophotometric methods. Blood pressures were measured using accosson sphygmomanometer. Data were analysed using analysis of variance and Pearson’s correlation coefficient at p < 0.05.
Results: The TAC was significantly higher in the pregnant normotensives (p< 0.05) compared with the pre-eclamptic and non-pregnant normotensives. There was no significant difference in the MDA in pre-eclamptic compared with pregnant normotensives and non-pregnant normotensives (p>0.05). A significant difference was observed in the SOD and GPx activities in the pregnant normotensive and non-pregnant normotensives compared with pre-eclamptic. A positive correlation was observed between the blood pressures (systolic and diastolic) and the activities of TAC, SOD and GPx in pre-eclamptic. Furthermore, a positive correlation was observed between MDA levels and SBP (r = 0.019) while a negative correlation (r = -0.225) existed between MDA and DBP.
Conclusion: Diminished ability of antioxidants to scavenge free radicals may affect the onset of pre-eclampsia and therefore possible prognostic tool in its management.
Forward Error Correction Using Turbo Codes for Multimedia Data
Authors: Subramanya M. , Khuteja Shaiesta , C. Varun Kumar K. , Srilatha S. , V. Srividya B. 
Published: October 2019

The swift growth in multimedia technology of wireless network has made it mandatory for the efficient transmission across erratic channel. The transmission of encoded video using error control techniques is grabbing a great attention, since it works over the recovery of the lost data and errors in the bit frames which occur as a result of congestion and physical channel fading. Turbo codes are attracting researchers because of their efficient performance. The Turbo code is made up of analogous concatenation of two Recursive Systematic Convolutional (RSC) coders parted by a non-uniform interleaver. For different code rate and information block lengths greater than 104, these codes are capable of achieving low Bit-error rates (BERs) at SNRs within 1dB of Shannon’s limit. Turbo codes will assist to employ Viterbi decoders. More the number of iterations, higher is the error correction capacity and hence Turbo codes act as an elucidation for obtaining large coding gains.
Reliability Assessment of a Base Transceiver Station Using 2-Parameter Weibull Distribution Method
Authors: Idiapho Onoriode K. , Odinikuku William E. 
Published: October 2019

About 80% interruptions of cellular network availability occur due to power outage on BTS stations and reliability analysis of these systems is yet to receive exhaustive studies. Most network providers solely depend on generating power on their BTS sites using diesel generators since the grid power is least reliable, but the frequency of power outages from the diesel generators is alarming, hence, the need to analyse the reliability of these generators and their maintenance routine in relation to the site availability.
In this study, the reliability of a Base Transceiver Station (BTS) is assessed by analysis of data obtained within a period of six months from four BTS sites used as case study using 2-parameter Weibull failure distribution method. The failure times of each BTS site were rank-ordered and the estimates of Weibull parameters θ and β were obtained from Weibull least-squares plots.
The Weibull plots for the four BTS sites had a good index of fit which shows that a strong linear relationship exists. The value of the shape parameter (β) was found to be between the range of 1< β < 3 for all the BTS sites studied. This means that the probability density function is skewed and the failure rate of the BTS sites is increasing. The reliability of each BTS site was successfully computed. The reliability of the four BTS sites was found to be increasing as their values of scale parameter, θ increases. From the results obtained, BTS site RV0144 had the highest reliability while BTS site RV0248 had the lowest reliability.
A Computerized Boundary Element Algorithm for Modeling and Optimization of Complex Magneto-Thermoelastic Problems in MFGA Structures
Authors: Fahmy Mohamed Abdelsabour , Al-Harbi Saleh M. , Al-Harbi Badr Hamedy , M. Sibih Alanod 
Published: October 2019

Aims: The aim of this article is to propose a boundary integral equation algorithm for modeling and optimization of magneto-thermoelastic problems in multilayered functionally graded anisotropic (MFGA) structures.
Study Design: Original research paper.
Place and Duration of Study: Jamoum laboratory, January 2018.
Methodology: a new dual reciprocity boundary element algorithm was implemented for solving the governing equations of magneto-thermoelastic problems in MFGA structures.
Results: A numerical results demonstrate validity, accuracy, and efficiency of the presented technique.
Conclusion: Our results thus confirm the validity, accuracy, and efficiency of the proposed technique. It is noted that the obtained dual reciprocity boundary element method (DRBEM) results are more accurate than the FEM results, the DRBEM is more efficient and easy to use than FEM because it only needs the boundary of the domain needs to be discretized.
A Review of Soil Dynamics in Traction Studies
Authors: Sedara A. M. 
Published: October 2019

As the world population increases more than ever before and increasing demand on food, feed and fiber, and security, the number of off-the-road vehicles is rapidly increasing for agriculture, forestry, military, mining and construction industries. Many researchers have studied and still investigating traction as it relates off-road vehicles and publications abound especially from developed countries of Europe, America and others. In our generation scientists are trying to put robotic vehicles on the lunar and Martian terrains. This trend makes the study of soil dynamics in traction a sine qua non in our tertiary and research institutions. In Nigeria there is a dearth of publications in this specialized area of study. This is a review paper and the purpose is to highlight some of the studies that have been conducted over the years, with a view to enlightening, encouraging, stimulating and challenging would be researchers. Trends in the development of soil bin with single wheel testers were reviewed including tractive and transport devices used in them. Traction parameters including motion resistance, measurement and data acquisition systems, traction predictive equations including wheel numeric and mobility numbers were also reviewed. Efforts made in the development of soil bin for soil dynamics research and further research interest at the Federal University of Technology, Akure (FUTA) were highlighted.
Performance Evaluation of a Portable Ginger Slicing Machine
Authors: Abubakar I. , Yusuf D. D. , Muhammed U. S. , Zakariyah A. , Agunsoye J. K. , Habiba K. A. , Bashar Z. U. 
Published: October 2019

The study aimed at evaluating the functional performance of a developed portable ginger rhizomes slicing machine. The study was conducted at various levels of impeller speed, impeller gang and slicing compartment in the Department of Agricultural and Bioresources Engineering, Ahmadu Bello University, Zaria, Nigeria between April 2018 and June 2018. A factorial experiment in a Completely Randomized Design (CRD) was used. The indices for the performance evaluation were the Slicing Efficiency and Throughput Capacity. The machine was powered by one horse power petrol engine and ginger moisture content of 77.44%. Data collected were subjected to statistical analysis using Analysis of Variance (ANOVA) to test the significance level of the experimental factors and their interactions; and those found significant were further subjected to Duncan Multiple Range Test (DMRT) for mean separations at (P = .05), respectively. The results showed that, the ANOVA for all the factors evaluated and their interactions on Slicing Efficiency were highly significant at (P ≤ .01). However, the ANOVA for the factors evaluated on Throughput capacity were highly significant but interaction between type of compartment and speed of impeller was not significant at (P =.05). The mean Slicing Efficiencies for the cushion and spring compartments were: 63.5 and 50% while the mean Throughput Capacities were: 58.32 and 6.32 kg/h, respectively.
Performance Evaluation of Drip Irrigation Systems on Production of Okra (Hibiscus esculentus) in Southwestern, Nigeria
Authors: Amoo M. O. , Ademiju T. A. , Adesigbin A. J. , Ali G. A. 
Published: October 2019

This study was carried out to evaluate the performance of drip irrigation systems on the production of okra (Hibiscus esculentus) in southwestern, Nigeria. Application of water to crops in an area of scarcity of water is very important to meet the food demand of the ever-increasing population and modified irrigation techniques that can assist the okra farmers to have affordable irrigation systems that will get them great yields at the end of the season was evaluated in this paper. A field experiment was conducted at the Teaching and Research farm of Agricultural and Bio-Environmental Engineering Department, School of Engineering Technology, The Federal Polytechnic, Ado, Ekiti - State, Nigeria. The field area of 150 mby 400 m was properly cleared, stumped, ploughed and harrowed. The topography of the land was flat with its suitable soil structure, texture, retention capacity and loamy clay soil. The cultivated area of land was divided into three and on each experimental plot, high yield and disease resistant okra variety seeds obtained from a research institute (IITA) were carefully selected and planted at a regular interval of 0.6 m. Drip laterals were laid in between rows of okra plants with inline drippers at a spacing of 20 cm. The parameters measured include okra seed germination, plant height, stem girth, number of leaves and yield production. The study also includes soil properties, crop water requirement and crop water use efficiency. There were no significant difference in the okra agronomic parameters at each experimental plots under drip irrigation system. The water applied to crop was greater than the actual crop water requirement and the efficiency of the drip irrigation was 68.5%. There is high in seed germination percentage in with 3.5%, 3.6% and 3.8% at each experimental plot respectively. The selected okra agronomic parameters showed that okra performed very well under drip irrigation systems. Based on the results, water application through drip irrigation has a positive impact on growth and vegetative development of okra.
A Study of Vacuum Efficiency for Silicon on Insulator Wafers
Authors: Bacquian Bryan Christian S. , Gomez Frederick Ray I. 
Published: October 2019

The development on thinner packages has become the trend and focus in semiconductor packaging industry. The necessity of thinner packages also entails a thinner vertical structure of the integrated circuit (IC) design. As a major contributor on the vertical structure of the IC package, die or wafer is also essential to go thinner. As the wafer goes thinner, various problems may occur during transport and even the back grinding process, itself.
Wafer warpage is one of the main concerns during the process. The effect of proper vacuuming will play major role in processing SOI wafers. Insufficient vacuum may cause non-planar wafer in contact with the chuck table that may result to poorer grinding and worst broken wafer.
Different silicon wafer technology has been released to cater different functionality on different industry markets. One popular silicon technology is Silicon On Insulator (SOI) technology. SOI wafers have a step type passivation wherein the edge of the wafer is observed to have 30um thinner than its center. The stepping effect also contributes to the 0.5mm wafer warpage prior back grinding. Evaluating the effect of vacuum efficiency to eliminate such warpage is discussed on this technical paper.
Comparative Study of Weekly Discharge Rate of Two Solar Batteries Commonly Used in Anambra State
Authors: Marymartha Ugbaja, Chikodiri , Ikeh C. U. , Egwuonwu G. N. 
Published: October 2019

The purpose of this study is to compare the weekly discharge rate of two solar batteries commonly used in Anambra State. The batteries considered were the Indian made battery with specification Luminous, Deep cycle sealed maintenance free batteries solar application, Lum 12V 100Ah 20hr and 3DGP161433 and Chinese made battery with specification Sun-Test std gel battery, 12V-100Ah, 010716w, Cycle use 14.4-15.0V, Stand by use; 13.5-13.8V and Initial current: less than 30A were used to power 2 stand-alone security lights at the Faculty of Physical Sciences, Nnamdi Azikiwe University, Awka. The technical assessment was based on measuring their output voltages bihourly from 19.00 hr to 7.00 hr and estimation of weekly discharge rate of these batteries for a period of two months (eight weeks). From the analysis, the Indian made solar battery has insignificant discharge tendency for the first eight weeks of its use having its discharge rate of -0.034, -0.038, -0.042, -0.037, -0.039, -0.038, -0.039 and -0.036 Volts/hr per week from week one to week eight respectively whereas the Chinese made solar battery has a relatively high discharge rate of Voltage/hr per week within the first eight weeks of its use having its rate at -0.095, -0.213, -0.103, -0.1, -0.104, -0.1, -0.083 and -0.109Volt/hr per week from week one to week eight. Also, while the Indian made battery is observed to be relatively stable, the Chinese made battery was observed to be very erratic and highly susceptible to discharge within the first eight weeks (two months) of its use. Hence, it is concluded that Indian made battery is preferred to that of Chinese made battery for optimal performance of stand-alone PV syste.
Friction Coefficients of Local Food Grains on Different Structural Surfaces
Authors: Nwakuba N. R. , Chukwuezie O. C. , Uzoigwe F. C. , Chukwu P. 
Published: October 2019

Knowledge of friction coefficient of agricultural commodities on various structural surfaces is imperative in the design and material selection for postharvest handling, transportation, processing and storage equipment. This paper presents the friction coefficients of local food grains on different structural surfaces as a function of moisture content. The experiment was conducted using a Complete Randomized Design (CRD) in a factorial treatment design to evaluate the influence of different structural surfaces (glass, mild steel, plastic, ply-board, and aluminium) and moisture content levels (6, 12, 18, and 24% wet basis) on the coefficient of friction of selected local grains (benniseed, finger millet, pearl millet, and hungry rice). Results obtained indicate that the friction coefficient (μ) of the studied grain samples increased linearly with increase in moisture level for all the tested structural surfaces. Within the range of the studied moisture content, benniseed exhibited the highest μ-value (0.526 ± 0.031 ≤ μ ≤ 0.784 ± 0.157) on ply-board, whereas hungry rice had the lowest value (0.248 ± 0.018 ≤ μ ≤ 0.527 ± 0.023) on glass material. Amongst the tested metal surfaces, aluminum had the lowest μ-value (0.236) at 6% moisture content. The effect of structural surfaces and moisture contents as well as their interactions on friction coefficient were statistically significant at P =.05 for all the studied grain samples. High values of correlation coefficient (R2) > 0.95 were obtained to indicate strong correlation between μ-values and experimental factors. A low coefficient of variation (CV) of 2.75% was obtained to show high experimental reliability.
A Critical Analysis of Multi-Regime Fundamental Equations
Authors: Akweittey Emmanuel , Fosu Gabriel O. 
Published: October 2019

Aims/ Objectives: Multi-regime fundamental models use two or more equations to describe the association among the main maroscopic traffic variables encountered in traffic analysis. The paper investigates specific properties of some multi-phase speed-density equations.
Methodology: It first compares the characteristics of each of these equations by solving the nonlinear continuity traffic equation.
Results: It was observed that predicting vehicular trajectories with these model equations could lead to misinformation. The kinematic wave and stable shockwave properties of these models were also ascertained.
Conclusion: Based on the results, it was concluded that it would be more cumbersome to explain nonlinear traffic characteristics when these two and three regime models are adopted.
Analyzing and Eliminating Die Passivation Crack in a Power Leadframe Package using Submodeling Approach
Authors: Talledo Jefferson 
Published: October 2019

This paper presents the submodeling approach in thermo-mechanical simulation of the die passivation crack encountered in a power leadframe package subjected to temperature cycling condition. Without using modeling and simulation in resolving semiconductor package development issues, the process would be very costly and time-consuming. For die passivation crack, the details of the different layers of the die passivation need to be modeled and this would result in a large simulation model with considerable solution time. However, a technique known as submodeling can be used to reduce solution time without sacrificing accuracy of results. In this study, submodeling was successfully used to analyze the stresses in the critical passivation layer that resulted in the best design that eliminated the passivation crack. The modeling result showed that the crack could be eliminated by using the right passivation material layer combination and thickness. An increase in the thickness of the material layers and the additional of sublayers have provided significant stress reduction in the topmost critical passivation layer resulting in crack elimination.