bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Plastic pH on Silicone Elastomer Compression Set
Authors: Coyne Christopher W.
Published: April 2021

Sealing applications in electrified vehicle powertrains present a unique set of boundary conditions when contrasted with typical transmission or internal combustion engine applications, including changes in fluidic exposure, operating pressure, temperature profiles, etc. This novel powertrain environment opens the gasket material spectrum to elastomers uncommon in standard powertrain joints, which allows for more optimized, higher-value sealing solutions. However, this also introduces new risks, including the risk of excessive compression set in silicone elastomers due to acidity in adjacent plastics (which can result from shifting to non-halogenated flame retardants from halogenated flame retardants). To understand this phenomenon, compression set testing was conducted with plastic resins ranging from pH = 3.4 to pH = 7.3 and three high-consistency rubber (HCR) silicone elastomers. For each silicone, compression set was plotted linearly against concentration of hydrogen ions ([H+]) in the plastic and plotted exponentially against plastic pH. This produced a regression model relating compression set in the elastomer to acidity of the adjacent plastic. Then, a threshold pH value - after which the plastic begins to significantly increase compression set in the silicone - was determined by overlaying silicone-only compression set results with the silicone + plastic regression model. The resulting threshold value given the associated conditioning was a pH of 4.5 for all three silicone samples tested, indicating that a plastic resin accelerates compression set in the neighboring silicone if the plastic has a pH ≤ 4.5. Studies into the impact of (1) plastic sample form factor (raw material pellets, colorized material pellets, or molded plastic sheets) and (2) time on plastic pH were evaluated; both showed no statistical impact on pH measurements. Overall, this effect is believed to be due to acid-induced cleavage of the siloxane bond, which causes depolymerization in the silicone by breaking the backbone chain, thereby resulting in gasket compression set.
Analysis of Formaldehyde Scavenger and Its Reaction Products in POM Using Mass Spectrometry
Authors: Jang Hye Jin , Jeong Chan Ho
Published: April 2021

To meet the indoor air quality guideline of newly manufactured vehicles in Korea, China, and other countries, low formaldehyde grade POM (Polyoxymethylene) is used for interior parts essentially. In this paper, formaldehyde scavengers from of 2 commercial low formaldehyde grade POM pellets were identified by LC-MS (Liquid chromatograph-Mass spectrometer) as sebacic dihydrazide and dodecanedioic dihydrazide respectively. The reaction products between formaldehyde and formaldehyde scavengers were also detected, which were converted from hydrazide to hydrazone. So, this kind of additive would be gradually consumed by repetitive molding process or exposure to heat according to formaldehyde emission increase. We are expecting to apply this analytical method and result for quality control and benchmark of low formaldehyde grade POM.
Forecasting Short to Mid-Length Speed Trajectories of Preceding Vehicle Using V2X Connectivity for Eco-Driving of Electric Vehicles
Authors: Hyeon Eunjeong , Shen Daliang , Karbowski Dominik , Rousseau Aymeric
Published: April 2021

In recent studies, optimal control has shown promise as a strategy for enhancing the energy efficiency of connected autonomous vehicles. To maximize optimization performance, it is important to accurately predict constraints, especially separation from a vehicle in front. This paper proposes a novel prediction method for forecasting the trajectory of the nearest preceding car. The proposed predictor is designed to produce short to medium-length speed trajectories using a locally weighted polynomial regression algorithm. The polynomial coefficients are trained by using two types of information: (1) vehicle-to-vehicle (V2V) messages transmitted by multiple preceding vehicles and (2) vehicle-to-infrastructure (V2I) information broadcast by roadside equipment. The predictor’s performance was tested in a multi-vehicle traffic simulation platform, RoadRunner, previously developed by Argonne National Laboratory. The simulation results show that the proposed predictor’s improved predictions can reduce energy consumption by 5% over eco-driving with the baseline predictor.
Application of Dynamic Skip Fire for NO
x
and CO2 Emissions Reduction of Diesel Powertrains
Authors: Srinivasan Vijay , Wolk Benjamin , Cai Xiaoping , Henrichsen Lars , Lee Justin , Patil Devyani
Published: April 2021

Dynamic Skip Fire (DSF®) has been shown to significantly reduce CO2 on gasoline engines and has been in mass production since 2018. Diesel Dynamic Skip Fire (dDSF™) builds upon the technology and extends it to diesel engine applications. dDSF is an advanced cylinder deactivation technology that allows the deactivation of any number of cylinders dynamically to deliver the requested torque while maintaining acceptable noise, vibration, and harshness (NVH) performance. NOx regulations are becoming progressively more stringent on light, medium and heavy-duty (HD) diesel engines. Meeting low NOx standards is becoming increasingly challenging, especially in lightly loaded operating conditions where maintaining ideal aftertreatment system efficiency is difficult. Most existing techniques to increase aftertreatment temperatures at low loads incur a fuel consumption penalty, which increases greenhouse gas emissions. In this study, dDSF is shown to combine benefits by reducing both NOx and CO2 simultaneously. Detailed studies were conducted on a Cummins X15 HD diesel engine. Engine testing and vehicle level simulation studies were followed by transient testing conducted on an engine dynamometer as well as on-road vehicle tests. NVH testing and evaluation was performed at the vehicle level to characterize vehicle response and ensure acceptability. dDSF calibrations were optimized to provide best thermal benefits at low loads. System level considerations such as coordination of air handling and fueling during transitions between firing densities, detection of valve actuation errors and mitigation of oil consumption concerns were studied. Results from system simulations using engine test data show 74% reduction of NOx and 5.0% reduction in CO2 on the Low Load Cycle (LLC) compared to the baseline engine with conventional thermal management. This simultaneous reduction helps compliance of NOx regulations while also reducing overall greenhouse gas emissions.
Review on State of Health Definition in Relation to Proton Exchange Membrane Fuel Cells in Fuel Cell Electric Vehicles
Authors: Hu Xiao , Zhang Tong
Published: April 2021

Owing to its advantages of high energy density, quick start-up, and no emissions, the proton exchange membrane fuel cell (PEMFC) is one of the most promising power sources in transportation and has been used for automotive application for years. However, shortcomings in fuel cell key performances, such as lifetime and efficiency, characterized by state of health (SOH), restrict the large-scale commercialization for fuel cell electric vehicles (FCEV), raising demands for real-time state monitoring. Nowadays, most researchers have explored the reasons for state change from models or experiments. Nevertheless, it is in need of system-level researches on definition methods of SOH against the actual automotive application. Lacking accurate quantitative indicators, existing studies on health states are often qualitative and hence fail to consider intermediate processes. In addition, too many health indicators that describe typical physical characteristics can be used for SOH definition, which raises higher demands for the computational cost. Moreover, most researches focus on long-term degradation and overlook the importance of short-term performance changes. The research on the definition of health states aims to execute the control strategy more effectively after system monitoring, which is also influenced by key components coupled with PEMFC in powertrain system, including battery and DC/DC converter. Therefore, focusing on FCEV and based on the literature research method, latest technologies on SOH definition of PEMFCs and related estimation methods are reviewed. Based on comprehensive analyses, this paper proposes the development direction of researches on the SOH study for FCEVs, and provides helpful guidelines for the monitoring performance and optimizing control from system level for practical applications.
Development of Air Supply Controller for FCV Based on Model-Based Development Approach
Authors: Tomi Naoki , Hasegawa Shigeki , Farnsworth Jared , Imanishi Hiroyuki , Ikogi Yoshihiro , Sato Kenichiro
Published: April 2021

In Toyota’s 2nd generation FCV, an electric turbo-type air compressor has been adopted for downsizing and cost reduction. Automotive Fuel Cell applications present several challenges for implementing a turbo-type air compressor. When operating a fuel cell in high-temperature or high-altitude locations, the FC stack must be pressurized to prevent dry-up. The flow rate vs pressure conditions that the FC must pass through or in some cases operate at are typically within the surge region of a turbo-type air compressor. Additionally, Toyota requires quick air transient response (< 1 sec) for power generation, energy management, and FC dry-up prevention. If the turbo-type air compressor is not precisely controlled during quick transients, it can easily enter the surge region. To solve the above issues, we developed a new air supply controller which can avoid compressor surge by controlling 3 variables, ‘FC stack air flowrate’, ‘FC stack air pressure’, and ‘FC stack air Bypass’ independently with high accuracy. The controller was designed using a model-based development approach. At first, the physical characteristics of the air systems compressor, valves, pipes, and FC stack were modeled and integrated into a system level simulation that can run real-time on-board the vehicle Engine Control Unit (ECU). Next, the feedforward and feedback (PI) control were developed by implementing inverse models of the air system component equations. We confirmed that this control development approach could achieve Toyota’s air supply control performance requirements and prevent turbo-type air compressor surge.
A Study on Parameter Variation of Cells Effects on Battery Groups with Different Topologies and Load Profiles
Authors: Lingzhao Kong , Lee Runfeng
Published: April 2021

To satisfy the power and energy requirement of the systems, such as electrical vehicles, the battery packs are constructed with hundreds of single cells connected in series and parallel connection. The most significant difference between a single cell and a battery pack is cell-to-cell variation. Not only does cell-to-cell variation have a big effect on the available energy and power of the battery packs, but also it causes early degradation of battery and potential safety issues. The cell variation effects on battery packs are widely studied because it is of great significance for battery sorting and management scheme. In this paper, battery pack inconsistency is clearly defined and the resulting battery capacity loss and aging acceleration problems are analyzed in detail. A comprehensive LiFePO4 battery pack model was established, which has taken into account cell-to-cell variation, thermal model, capacity degradation, resistance increasing and different battery topologies. A set of parameters are introduced to study the cell variation and their impacts on battery pack are analyzed through the different working conditions simulation. The battery sorting suggestions are given based on the quantitative result from the simulation. The quantitative results from this research demonstrate that the capacity, self-discharge rate and initial SOC in series battery group, capacity, resistance in parallel connection are the major affecting parameters of cell-to-cell variation, which leads to significant aging acceleration and capacity loss of the battery pack. In the meanwhile, it has been pointed that dynamic load profile caused faster cycling aging and more serious self-balancing compared with the constant load profile.
Impact of Power Profile on the Estimation of Second Life Batteries Remaining Useful Life
Authors: Battaglia Daniele , D'Arpino Matilde , Ganesh Sai Vinayak , Carlson Joseph
Published: April 2021

Second-life batteries (SLBs, automotive batteries that have lost their usefulness for vehicular applications) can provide low-cost environment-friendly solutions for grid-connected systems. The estimation of the remaining useful life (RUL) of SLBs is a fundamental step for the development of appropriate business models. This paper aims at unveiling correlations between the SLB's power profile and aging performance by defining appropriate metrics. A widely accepted empirical degradation model, that can predict calendar and cycling aging, is considered for this study. Several grid-connected power profiles are analyzed, such as peak shaving for DC-fast charge stations and frequency regulation. The results of this analysis show a correlation between the SLB's replacement rate with the minimum daily SoC.
Implementation of Thermomechanical Multiphysics in a Large-Scale Three-Dimensional Topology Optimization Code
Authors: Najmon Joel , Wu Tong , Tovar Andres
Published: April 2021

Due to the inherent computational cost of multiphysics topology optimization methods, it is a common practice to implement these methods in two-dimensions. However most real-world multiphysics problems are best optimized in three-dimensions, leading to the necessity for large-scale multiphysics topology optimization codes. To aid in the development of these codes, this paper presents a general thermomechanical topology optimization method and describes how to implement the method into a preexisting large-scale three-dimensional topology optimization code. The weak forms of the Galerkin finite element models are fully derived for mechanical, thermal, and coupled thermomechanical physics models. The objective function for the topology optimization method is defined as the weighted sum of the mechanical and thermal compliance. The corresponding sensitivity coefficients are derived using the direct differentiation method and are verified using the complex-step method. The design variables are updated using the method of moving asymptotes so that the objective function is minimized resulting in maximum performance of the structure. Solution of the linear systems of equation is scaled across several supercomputer nodes using the Portable, Extensible Toolkit for Scientific Computation (PETSc) developed by Argonne National Laboratory. The finite element models, sensitivity analysis, optimization algorithm, and solver are all implemented in a freeware, density-based, topology optimization code (written in C++) that has been modified for thermomechanical problems. As such, the implementation of the thermomechanical model is provided. The code is applied to solve an example problem under thermal, mechanical, and thermomechanical boundary conditions. The resulting topologies and field variables are shown with a corresponding discussion.
Remediation of Crude Oil Contaminated Soil, Using Organic Supplement: Effects on Growth and Heavy Metal Uptake in Cassava (Manihot esculenta Crantz)
Authors: Osu S.R. , Udosen I.R. , Udofia G.E.
Published: April 2021

Field experiments were conducted in 2016 and repeated in 2017 to evaluate the effectiveness of Oil Palm Bunch Ash (OPBA) and Dried Poultry manure (DPM) as organic supplement, applied singly and in combination on growth properties and heavy metal uptake of cassava cultivars grown in crude-oil contaminated soil of the Niger Delta Region, Nigeria. There were four different organic amendments viz: DPM, OPBA, OPBA +DPM and control using TMS 30572, NR8082 and local variety as test crops. Results were elaborated statistically with the use of three-by-four factor variance analysis with ANOVA. Effect of various application of amendment on morphometric parameters of cultivars revealed in 2017 that at 36 weeks after sprouting (WAS), DPM and OPBA +DPM significantly (P≤ 0.05) enhanced plant heights of TMS 3572 and LV but had no influence on number of nodes, stem girth and leaf area. However, the interactions resulted in significant (P≤ 0.05) uptake and concentration of the heavy metals Fe, Cu, and Pb in leaves and Fe in roots ofTMS30572 and NR8082, indicating efficient metal removal by these varieties. Results of amendment also revealed remarkable increment in bacterial and fungal (from 104 to 106 and 103 to 104 ) populations respectively, correlating with reduction in soil total petroleum hydrocarbon (TPH) from 156.45 mg/kg to 146.73 mg/Kg. This is observed to diminish oil toxicity and improve soil status. The response of these cassava varieties to crude oil contamination appears to be optimistic. Consequently crop farmers are adviced against planting cassava and other arable crop at crude oil impacted soil for the risk of uptake of heavy metal in crop tissues.

Keywords: Remediation, Heavy metal, Oil-contaminated soil, Organic amendment, Growth properties, Cassava
Health Risk Assessment for the Exposure of Workers to BTEX at the Gasoline Stations
Authors: Giao Nguyen Thanh , Anh Phan Kim , Nhien Huynh Thi Hong
Published: April 2021

The study was conducted to assess the health risks of workers due to exposure to toxic gases including benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde and acetaldehyde at gasoline retail stations. In this study, data on the  concentrations of the toxic gases were collected from the previously published studies in the qualified scientific journals. The health risk assessment was followed by the process of the United States Environment Protection Agency (U.S. EPA). The results show that the concentrations of benzene, toluene, ethylbenzene, m, p-xylene, o-xylene, formaldehyde, and acetaldehyde were in the range of 12.40 - 357.5, 12.47 - 574.17, 2.05 - 156.5, 4.57 - 218, 2.36 - 77.04, 3.64 - 153.93 and 1.27- 27.83 µg/m3 , respectively. Life time cancer risk for gasoline station workers due to exposure to benzene, ethylbenzene, formaldehyde, and acetaldehyde was calculated in the ranges of 2.13x10-5 - 6.14x10-4 , 4.96x10-7 - 3.79x10-5 , 4.81x10-6 - 2.03x10-4 , and 7.99x10-7 - 1.75x10-5 , respectively. For non-carcinogenic  compounds, the hazard index due to benzene, toluene, m, p-xylene, o-xylene were respectively in the range of 0.13 - 3.81, 7.97x10-4 -  0.04, 0.01 - 0.70 and 0.01 - 0.25. The findings revealed that there is high risk of cancer and non-cancer for the workers working at the gasolines stations if they are not taking good preventive measures. The calculation showed that the limit levels of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde should be reduced to 5.82x10-4 , 15.64, 4.13x10- 3 , 0.31, 7.57x10-4 and 1.59x10-3 mg/m3 , respectively to meet the safety levels for the workers at the gasoline stations.

Keywords: benzene, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, life-time cancer risk, health
Factors Influencing Soil Erosion Management Practices in Ejersa Lafo District, West Showa Zone, Oromia, Regional State, Ethiopia
Authors: Leta Amenu , Megersa Terefe
Published: April 2021

Soil erosion by water is the major Agricultural problem, which results in reduction of agricultural productivity. This study focused on farmer perception of soil erosion and factors influence soil erosion management practices. A cross sectional data was used to assess information about soil erosion perception and factors influence soil erosion management practices. The Ejersa Lafo district was purposively selected from the districts of West Shoa Zones. A total of 142 sample respondents were randomly selected. Interview questionnaire, focus group discussion and survey of field observation were used as data collection tools. Data were analyzed using descriptive statistics and econometric model. Result from descriptive statistics show that majority of the respondents perceived soil erosion problem and its consequence on farmland. Both biological and physical soil erosion management practices in the area. Binary logit model estimation result shows that education level, landholding size, slopes of the land and land ownership type were mostsignificant to soil erosion management practices in the area. Therefore, taking these factors into account in setting appropriate soil erosion management measures may help policy makers and farmers to couple with erosion problem. The study recommended a need for the government to enforce effective policies to control and prevent soil erosion problem.

Keywords: Binary logit model: Management practices: Soil Erosion
Conservation Status and Habitat Preferences of Common Warthog (Phacochoerus Africanus) in Old Oyo National Park, Nigeria
Authors: Adeola A.J. , Adeyemo A.I. , Ejidike B.N. , Olaniyi O.E. , Akande O.A. , Ajayi S.R. , Azeez O.K.
Published: April 2021

This study assessed the conservation status and habitat preference of Common warthog in Old Oyo National Park, Nigeria using direct sighting and line transect method. The abundance estimate and encounter rate of common Warthog in the study area from 2018-2019 showed that year 2018 recorded 213 individuals at an encounter rate of 0.38/km while year 2019 recorded 184 individuals at an encounter rate of 0.32/km while the mean abundance estimate of common Warthog are 4.65±0.64 and 1.71±0.48 which represents 156 and 58 individuals at encounter rate of 0.55/km and 0.20/km in the wet season and dry season of year 2018 compared to year 2019 with average abundance estimate value of 4.00±0.85 and 1.41±0.61 which represents 135 and 48 individuals at an encounter rate of 0.47/km and 0.17/km for wet and dry season respectively. The mean age structure and sex ratio of the observed warthog population during dry and wet seasons revealed that juveniles had highest mean of age structures among the populations observed across the seasons. The habitat preference of common warthog revealed that they are mostly found in mixed woodland and open savanna with 112 observation and the lowest was recorded in the outcrop vegetation and open savanna with 21 individuals.in the wet season. During the dry season, mixed woodland/open savanna and Riparian grassland had the highest sightings of 45 and 33 individuals each. The outcrop vegetation/open savanna had the lowest observation of 1 individuals only. The study also recommends that more aspect of the ecology of the animal should be studied in details and emphasis should be placed on the habitat requirements.

Keywords: Conservation, Estimate, Status, Warthog
Socio-Economic Importance of Tree Nursery Enterprises in Lagos State, Nigeria
Authors: Eko O.D. , Adedokun M.O. , Soaga J.A. , Okojie L.O. , Atanda T.A. , Abisoye T.
Published: April 2021

There is a growing interest to understand the role of tree nursery enterprises in Nigeria and the horn of Africa. Tree nursery  enterprises, which are vital economic activities in major cities of Nigeria and particularly in the city of Lagos are not adequately studied and well documented. Therefore, this study seeks to fill a gap in understanding the socioeconomic importance and profitability potential of tree nursery enterprises. Multistage sampling technique with a 3-stage design was adopted in this study using aquantitative data collection techniques through the use of structured questionnaire administered to 120 nursery entrepreneurs. Data were analyzed using descriptive, inferential, and budgetary analysis. The result revealed that tree nursery entrepreneurs are literate, mostly male in their youthful age. Furthermore, the total annual revenue earned by the respondents was ₦1,712,222.22 with a mean annual net income of ₦1,458,038.72 while the return per naira invested was ₦5.71. This shows that tree nursery enterprise is profitable in the study area. However, most entrepreneurs were faced with shortage of land for establishments of tree nursery in the study area. Therefore, appropriate actions in reducing cost of land lease/purchase are recommended to encourage new entrepreneurs and strengthen the sector’s development.

Keywords: Entrepreneur, Environment, Nursery enterprises, Profitability, Socio-economic and Tree seedlings.
Performance Evaluation of Outpatient Department Waiting Line System in a City Hospital in Nigeria
Authors: Adaji I. , Lawal A. , Abdullahi A. , Abdulkadir A.
Published: April 2021

In this paper, performance evaluation of outpatient department waiting line system in a city hospital in Nigeria has been studied using a multiple server queuing model. The relevant data used in the research were collected for a period of four weeks through direct observations and interviews. The results of the research showed that with Two Doctors for the morning session patients spent an average of 1.0233hours in the system, out of which 0.932hours are spent on the queue with 95.45% Doctor Utilization. When the numbers of the Doctors were increased to 3, 4 and 5, it was found that a patient will spend an average of 0.125hours, 0.0975 hours and 0.0924hours in the system respectively. In each of the 3, 4 and 5 Doctors increased, the system will have 63.64%, 47.73% and 38.18% Doctors utilization respectively. With one Doctor for the evening session, the system has 54.55% Doctor Utilization and patient spent0.2hours in the system. The overall results showed that there is need to increase the number of Doctors to 3 or 4 for the morning session to achieved optimal service delivery while one Doctor in the evening session should be maintained. The results from the research could serves as important information to the management of the hospital for better services delivery.

Keywords: Doctors, Patient, Doctor Utilization, Queuing model, Evaluation
Web-based health service management for the eye
Authors: Onwuzo J.C. , Osodeke C.E. , Chigbundu E.K. , Kalu B.N.
Published: April 2021

This research was designed for the purpose of patients with eye defects who have difficulty visiting their doctors due to age, distance, or the manual processes involved in the existing system. We designed an approach to assist people get attended to by building a system that allows users register and log into the system, book appointments, view doctors and equipment used or available in the existing system. Joint Application Development (JAD) was the system methodology used, this is because it involves continuous interaction with the users and different designers of the system in  development. Quantitative and qualitative research methodology were employed, and method of data collection used were questionnaire, interview, and internet. The resultant website developed using JavaScript, CSS, PHP, HTML, and MySQL allows users register and log in, schedule doctor’s appointment, and book surgery.
Empirical evaluation of basic Information and Communication Technology (ICT) skills of final year students of Federal College of Education (Technical), Omoku
Authors: Okechi Onyedimekwu , Memoye Oruan K.
Published: April 2021

This research work titled “Empirical Evaluation of Basic Information and Communication Technology (ICT) Skills of Final Year Students of Federal College of Education (Technical), Omoku” used UNESCO ICT-Competency Framework for Teachers version 3, 2018 as a conceptual framework to assess basic ICT skills and competency level of students. It employed evaluative survey design using questionnaire as the instrument of data collection, designed and administered to all the 51 Part-Time final year students. Analysis of the research result using SPSS Version 20 shows that 4 (7%) of the students lack basic ICT skills, 13 (25%) of them are average in the use of ICT tools and 14 (27%) of them have above average ICT skills. A mean of 3.7 shows that 74% of the students agree that their ICT Instructors possesses the requisite professional skills and competencies to teach. Since 25% of the students can averagely use ICT tools, the researcher recommends that the Government should implement the Monitory and Evaluation of its huge investment in ICT in Education by making sure ICT Facilities are used for teaching and learning in schools.
Fault mitigation in real-time cloud computing
Authors: Festus Osuolale A. , Sunday Adewale O. , Boniface Alese K.
Published: April 2021

The introduction of computers has been a huge plus to human life in its entirety because it provides both the world of business and private an easy and fast means to process, generate and exchange information. However, the proliferation of networked devices, internet services and the amount of data being generated frequently is enormous. This poses a major challenge, to the procurement cost of high performing computers and servers capable of processing and housing the big data. This called for the migration of organizational and/or institutional data upload to the cloud for highlevel of productivity at a low cost. Therefore, with high demand for cloud services and resources by users who migrated to the cloud, cloud computing systems have experienced an increase in outages or failures in real-time cloud computing environment and thereby affecting its reliability and availability. This paper proposes and simulates a system comprising four components: the user, task controller, fault detector and fault tolerance layers to mitigate the occurrence of fault combining checkpointing and replication techniques using cloud simulator (CloudSim).
Motivation, Implication and Autonomy at Work
Authors: Semuhoza Etienne Serupia
Published: April 2021

From two populations of the same institution not having the same level of autonomy in their respective positions, one makes the assumption that a  larger autonomy increases motivation, satisfaction and implication at work, this one referring to the intrinsic aspects of the activity rather than to  extrinsic dimensions. It is also verified that the aspects relating to autonomy vary according to the type of work and reflect a specific form of relation to work. The study concerns a sample of 230 employees on which a multivariate model is tested by the means of a series of regressions and then using confirmatory techniques basing on the content analysis. The results go in the sense of the previous research and consequently confirmthe formulated assumptions. The adequacy of the ideal model is confirmed by the confirmatory analysis carried out with the software SPSS.

Key Words: autonomy, working position, satisfaction, implication.
Youths and cyber insecurity in Nigeria: The role of religion in mitigating against the yahoo yahoo phenomenon
Authors: Osuntuyi Pius M. , Ireyomi Adenike O. , Aluko Oluwasegun P.
Published: April 2021

It is no news that countries all over the world are faced with one challenge or the other. Outstanding among all is the challenge of insecurity of lives and properties. In Nigeria, there is the scourge of internet fraudsters known as Yahoo Yahoo, which have swindled many unsuspecting victims their hard-earned resources. Interestingly, the teaming youth population are the major players when it comes to this societal menace. Despite various efforts being put in place by the government to forestall the activities of these fraudsters, the propagators have sought other avenues to continue to be relevant in their nefarious acts. Thus, using questionnaire and in-depth interviews to gather its data, the study traced the trend that led to the engagement of youths‘ in Yahoo Yahoo. It analysed the effect of the practice of Yahoo Yahoo. It also examined the major religions (Indigenous religion, Islam, and Christianity) in the country and the roles they play in mitigating against the Yahoo Yahoo phenomenon in the country.
The impact of subtle resistance to regional crop specialization: The case of maize farming in Rugeramigozi Marsh-Rwanda
Authors: Hahirwa Gumira Joseph
Published: April 2021

In the framework of the professionalization of the agricultural sector in Rwanda, a number of agricultural reforms including regional crop specialization, mono-cropping, use of improved seeds and chemical fertilisers among others have been initiated and have substantially contributed to the increase of agricultural products at the Rwandan local market. Even though the reform outcomes were promising, smallholder farmers had at the outset of the reform implementation opposed to the way crops were selected for their marshland and their reaction has influenced the reform implementation. This article explores the experience smallholder farmers have gone through during the initiation of new selected crops for their marshland, their reactions to the use of the mandatory seeds and the impact of their reactions. Findings reveal that farmers‘ discontents have slowed down cultivating maize because their preferred crop – the rice – considered more profitable was disregarded. To deter the implementation of growing maize, smallholder farmers have used strategic defiance in form of subtle argumentation, strategic silence, strategic apathy or indifference, ironical strategy among others and the impact of their stratagems have led to the amendment of the decision of growing undesirable crop(s) in their marshland. The latest data collected in October 2017 and January 2018 reveal clearly the blurred intentions behind farmers‘ reactions observed during the 2010 – 2012 research – they bring to light what they didn‘t dare to disclose then. This article shows finally that in any agricultural reform design, planners should consider all aspects upholding smallholder farmers‘ advantages and these are identifiable only if they participate proactively in the reform planning and implementation phases.
Causes of early motherhood, consequences and prevention strategies: The case of early pregnant teenagers
Authors: Sebaganwa Alphonse , Semuhoza Etienne Serupia
Published: April 2021

This paper examined root causes of early pregnant teenagers under 19 years old. We selected 30 young girls from 3 districts of the southern Rwanda, who have been pregnant between 2018, 2019 and 2020. We decided to use "life story telling" methods whose analysis led us to the surprising major findings like the fact that more than 70% of our sample got pregnancy after the school abandon, 80% did not have any or false information on the sexual education and 90% of men pregnancy responsible are under 23 years old and are single. The findings showed also that more than 70% of the samples have no both parents. The findings established that negative influences from peers and environment, care free attitude of parents among others were factors that pre-dispose the girl-child to early motherhood. Also the effects include disruption of academic process, school drop-outs and poor public image. It was therefore, recommended that schools and homes should be more protective and shields the girl-child from negative influences. Education of the girl-child should be free and compulsory to enable teenage mothers go back to school after nursing her baby as many would love to do but for financial constraints The findings showed also that more than 70% of the sample have no both parents.
“Male effect” and “temporary weaning” in synchronization of post-partum ovarian activity in Pelibuey ewes
Authors: Hernández-Marín J.A. , Cortez-Romero C. , Herrera-Corredor C.A. , Pérez-Hernández P. , Pro-Martínez A. , Gallegos-Sánchez J.
Published: April 2021

To evaluate the response of the “male effect” and “temporary weaning” on the synchronization of post-partum ovarian activity in Pelibuey ewes, an experiment was carried out using 78 Pelibuey ewes with suckling lambs. The ewes were separated from their offspring for 48 hours and randomly assigned to one of four treatments derived from the arrangement of two factors, “male effect” and “temporary weaning”, each at two levels. Treatments were: T1 (n = 20) control ewes, without “male effect” and without “temporary weaning”); T2 (n = 19) ewes without “male effect” and with “temporary weaning”; T3 (n = 20) ewes with “male effect” and without “temporary weaning”; and T4 (n = 19), ewes with “male effect” and with “temporary weaning”. The response to oestrus, return to oestrus, gestation rate and lambing rate were analysed using logistic regression. The onset of oestrus was analysed using survival curves. No significant differences were found for lambing rate and prolificacy among treatments. “Temporary weaning” (T2) and “male effect” (T3) did not influence the response to oestrus, rate and duration of return to oestrus, or gestation rate and fertility, and was similar to the control group (T1). The interaction of “male effect” with “temporary weaning” (T4) increased the response to oestrus, reduced the rate and duration of return to oestrus, and the gestation rate, but increased fertility. Synchronizing post-partum ovarian activity with “male effect” and “temporary weaning” reduces the onset of oestrus and the rate of return to oestrus, but increases the response to oestrus and fecundity in Pelibuey ewes.Keywords: Biostimulation, progestogens, prolificacy, prostaglandins, suckling
Response in nutritionally related blood metabolites, carcass traits and primal pork cuts of slow growing Windsnyer pigs fed on varying levels of potato hash silage
Authors: Ncobela C.N. , Kanengoni A.T. , Chimonyo M.
Published: April 2021

The response of Windsnyer pigs to diets containing varying levels of potato hash silage in nutritionally related blood biochemistry, carcass traits and primal pork was estimated. Thirty-six growing clinically healthy male Windsnyer pigs with an initial weight of 36 kg ± 4.89 (mean ± standard deviation (SD)) were randomly assigned to six experimental diets containing 0, 80, 160, 240, 320, and 400 potato hash silage g/kg dry matter (DM). Experimental diets were derived from mixing a summit diet containing no potato hash silage and a dilution diet containing 400 g potato hash silage/kg in various proportions. Pigs were allowed ad libitum access to diets and water. There was no relationship between inclusion levels of potato hash silage and albumin: globulin ratio, total protein, and uric acid. As inclusion levels of potato hash silage varied, there was a positive linear relationship between silage and albumin concentration. Globulin concentration had a positive quadratic relationship with the inclusion of potato hash silage. Inclusion levels of potato hash silage resulted in a positive quadratic relationship in alkaline phosphatase. There was a negative linear response in warm carcass weight and cold carcass weight to inclusion levels of silage. A negative linear response was observed in dressing percentage. Different inclusion levels of potato hash silage caused a positive quadratic relationship in cooler shrink. There were negative linear relationships between inclusion of potato hash silage with shoulder fat, carcass length and backfat thickness. There was a negative linear relationship between eye muscle area and inclusion level of ensiled potato hash. There was a positive quadratic relationship between hindquarter length (HQL) and inclusion levels of silage. The observed linear relationship between hindquarter circumference (HQC) and inclusion levels of potato hash silage was negative. There is a need to predict the optimum inclusion level of potato hash silage without compromising the healthiness and carcass yield of pigs.Keywords: Alkaline phosphatase, backfat thickness, cold carcass weight, cooler shrink, dorsal fat thickness, eye muscle area, hindquarter circumference, total protein
Use of polyethylene glycol to improve the utilisation of leguminous leaf meals in pigs: A review
Authors: Hlatini V.A. , Ncobela C.N. , Zindove T.J. , Chimonyo M
Published: April 2021

The use of leguminous leaf meal as feed ingredients for pigs needs to be intensified and improved. Leguminous trees and shrubs are valuable sources of protein, amino acids, and dietary fibre for pigs. Leguminous leaf meals are abundant in the tropical regions and their use as alternate protein-rich feed ingredients for pigs is promising. In tropics, climate change and vegetation management practices have certainly increased the availability of shrub legumes compared to grasses. There is, therefore, a need to resort on harnessing abundant and cheap feed resources to cope with environmental changes and rise of feed prices. Leguminous leaf meals are invaluable feed ingredients for pigs because of their relatively high crude protein and they are highly available. The leguminous leaves also thrive in, and tolerate, adverse climatic and soil conditions. However, their utilisation is limited by presence of polyphenolic compounds, particularly condensed tannins that inhibit their efficient use by pigs. Other challenges for the utilisation of legume-based leaf meal diets are the presence of thorns and high fibre content. If leguminous leaf meals are included in the diet beyond optimum levels, polyphenolic compounds can suppress appetite, promote feed refusal, reduce digestibility, and can induce toxicity in pigs. This warrants investigation on the use of tannin-binding agents (TBA) to improve nutrient utilisation of leguminous leaf meal-containing diets fed to pigs. The inclusion level of polyethylene glycol (PEG) in livestock diets has a huge potential to neutralise negative effects of undesirable polyphenolic compounds. Therefore, the current review aimed to assess the potential of PEG to inactivate tannin and amount of PEG to include for optimum pig performance.Keywords: Leguminous leaf meals, performance, pigs, polyethylene glycol, polyphenolic compounds
Effects of fermented bamboo vinegar liquid on growth performance, nutrient digestibility, faecal Escherichia coli concentration and ammonia emissions in growing pigs
Authors: Ahmed S.T. , Mun H-S. , Son S-B. , Yang C-J.
Published: April 2021

Fermented bamboo vinegar liquid (FBVL) was prepared through liquid fermentation of bamboo vinegar with multispecies probiotics, and its effect on growing pigs was investigated. A 42-day feeding trial with 84 growing pigs (28.0 ± 0.08 kg) was conducted to evaluate the effects of FBVL on growth performance, nutrient digestibility, faecal Escherichia coli concentration and faecal ammonia emissions. Pigs were randomly distributed to one of four dietary treatments, namely control, CTC (0.003% chlortetracycline), FBVL 0.2%, and FBVL 0.4%. Overall, the final weight and daily weight gain of the pigs in the CTC group were higher than that of pigs in the control group. Dietary supplementation with 0.4% FBVL reduced the feed intake of growing pigs, whereas the feed conversion ratio (FCR) was lower in the CTC supplemented group. The dry matter digestibility was higher in pigs fed CTC and 0.2% FBVL diets, and crude protein digestibility was improved in all treatment groups compared with control. The faecal E. coli numbers were reduced in response to CTC and 0.4% FBVL supplementation. Faecal ammonia emissions were reduced by dietary supplementation with CTC and FBVL at weeks 1, 2 and 3. In conclusion, dietary FBVL supplementation increased nutrient digestibility and reduced faecal E. coli population and ammonia emissions without negative effects on growth performance.Keywords: Chlortetracycline, digestibility, fermentation, probiotics, swine
Effect of energy sources on ovarian follicular dynamics and oestrous activity of Holstein cows
Authors: Useni B.A. , Muller C.J.C. , Cruywagen C.W.
Published: April 2021

The objective of the study was to evaluate the effects of three nutritional treatments, which differed in energy level and source, on preovulatory follicles, number of follicles and oestrous activity in dairy cows. Twenty two Holstein multiparous cows from the Elsenburg herd were used in this study. After parturition, cows were kept on kikuyu-ryegrass pastures on an ad libitum basis, and allocated to various levels and types of concentrate supplements, which differed in starch and fat contents. The control group received 7 kg/day of a control concentrate, and the treatment groups each received 12.6 kg/day of concentrate. The concentrates contained high starch-low fat (HSLF) and high starch-low fat/low starch-high fat (HSLF-LSHF) levels. The supplement in treatment HSLF was a glucogenic concentrate using maize as the energy source. The supplements in treatment HSLF-LSHF were a combination of a glucogenic concentrate, which was offered for the first 60 days in milk (DIM), similar to treatment HSLF, followed from 61 DIM by a lipogenic concentrate using wheat bran and calcium (Ca) salts of long-chain fatty acids as the energy sources. At 80 ± 10 DIM, cows were synchronized with an Ovsynch protocol without being inseminated before the ultrasonography observation. While they were detained in a shaded neck clamp, cows were assessed individually with an ultrasound scanner every three days for ovarian measurements and follicular activity until the subsequent oestrus. Results showed that ovarian and follicular measurements and the numbers of follicles in various follicle size classes were similar between nutritional treatments. However, the total ovarian follicular counts were significantly higher in cows that received the HSLF and HSLF-LSHF treatments, compared with their counterparts in the control group (i.e. 7.23 ± 0.22, 7.21 ± 0.14 and 6.53 ± 0.19, respectively), through possible improvement in nutritional status. Further research is required to investigate various energy levels and sources that enhance the viability and the quality of the oocyte ovulating from the dominant follicle and improve the intensity and length of the oestrous expression in dairy cows.Keywords: Energy nutrients, follicular numbers, heat expression, preovulatory follicle, ruminant
Effect of including canola meal in diets of slaughter ostriches (Struthio camelus var. domesticus)
Authors: Brand T.S. , Van der Merwe J. , Hoffman L.C.
Published: April 2021

Canola meal (CM) is a locally produced protein source that may be less expensive than soybean meal (SBM). This study evaluated the effects of replacing 0%, 25%, 50%, 75%, and 100% SBM with CM in diets for slaughter ostriches. The CM was added at the expense of SBM and other concentrates, with minor changes in other ingredients. Birds (n = 15 per treatment) were reared from 77 to 337 days old on the trial diets, which were supplied ad libitum for starter, grower, and finisher phases. Bodyweights and feed intake were measured during these phases. No differences (P >0.05) were found between treatments for live weight at the end of each phase, dry matter intake (DMI), average daily gain (ADG) and feed conversion ratio (FCR) over all the growth phases. Although no differences were observed in live weight at the end of each phase, the birds reared on the diet with 50% CM were heaviest at slaughter, and birds reared with 100% CM were lightest (P <0.05). Differences (P <0.05) between diets were observed for the weight at slaughter, weights of the liver and thyroid glands and the pH of the cold carcass. However, no differences (P >0.05) were observed between diets for fat pad weight, dressing percentage, and weights of thighs and Muscularis gastrocnemius. The results indicate that CM could replace SBM in the diets of slaughter ostriches without affecting production traits and slaughter yields.Keywords: alternative protein, average daily gain, canola, dry matter intake, feed conversion ratio, growth, ostrich nutrition, production