Active Drag Reduction of Ground Vehicles Using Air-Jet Wheel Deflectors

Seven turbulence models were used to simulate the flow within the wheelhouse of a simplified vehicle body. The performance of each model was evaluated by comparing the aerodynamic coefficients obtained using computational fluid dynamics (CFD) to data collected from wind tunnel experiments. The performance of large eddy simulation (LES) and detached eddy simulation (DES) was largely dependent on the time step and grid size to accurately resolve turbulent eddies. The standard k-e, realizable k-e, k-w, DES, and LES all trended towards a drag coefficient which was 20% lower than the experimental value. In all numerical cases, the lift coefficient was found to be at least 60% greater than the experimental value, but was consistent with numerical studies by other authors. The standard k-w and SST k-w models provided results which were the most consistent with experimental data for the three different mesh sizes. Two types of flow modification devices were then added to the simplified vehicle model to assess drag reduction potential. Conventional wheel defectors are compared to air-jet wheel defectors on wheel drag and overall drag reduction capabilities. Two parametric studies are conducted on the Fabijanic body at a Reynolds number of 1.6x105: a study on the variation of the size and location of a conventional wheel defector, and a study on the jet speed and location of an air-jet wheel defector. Results show that wheel drag is decreased as the height of the conventional wheel defector is increased, and that the further the conventional wheel defector is from the wheelhouse, the more sensitive the wheel is to changes in drag coefficient. The air-jet wheel defector successfully decreases the wheel drag. The closer the air-jet is to the wheelhouse the less of an impact it has on wheel drag, but the greater the impact on the overall drag of the simplified body. A maximum overall drag reduction of 2.76% is achieved with a configuration which also results in a wheel drag reduction of 16%. Air-jet wheel defectors were then simulated on the DrivAer reference model -- an open source model which blends features of the Audi A4 and the BMW 3 Series. The air jets were found to be less impactful at low speeds, but at higher speeds, they were observed to reduce wheel drag and cause an overall drag reduction of up to 5.1%. Even though jet speeds as high as twice the driving speed were investigated, and caused relatively large reductions in wheel drag, a jet speed approximately 2/3 of the driving speed was observed to cause the greatest overall reduction

Breeding for increased water use efficiency in chickpea

Water use efficiency (WUE) is a complex trait, hence secondary traits which are genetically associated with WUE and have a positive association with yield, easy to measure and have genetic variation can be used as breeding targets for high WUE. The aim of the present study was to discover the variation for water use efficiency and grain yield in different tillage and irrigation regimes; the basis of yield formation under water limited conditions and develop a chickpea ideotype. The field experiment was conducted at the Plant Breeding Institute, the University of Sydney in Narrabri, northwest New South Wales in Australia. A total of 36 entries were planted replicated twice under well-watered and water-stress conditions, and no-till and till regimes. Water use was monitored using a neutron probe moisture meter and water use efficiency calculated using the soil water balance method. Grain yield was higher under irrigation at 1722 kg/ha than rainfed conditions at 1478 kg/ha. No-till had 7.4% higher yield than the till regime. WUE was higher under no-till (5.02 kg/ha/mm) than under till (4.87 kg/ha/mm) and higher under irrigation (5.05 kg/ha/mm) than under rainfed conditions (4.84 kg/ha/mm). There was a strong association between grain yield and WUE under rainfed conditions, thus high yielding genotypes had high WUE. Sonali had the highest yield and WUE. Normalised difference vegetation index (NDVI) at early podding and late podding and chlorophyll content at late podding were useful marker traits in identifying genotypes with potentially high yield and high drought tolerance. Sonali, ICCV 96853 and PBA Slasher were identified as drought tolerant genotypes. The constructed chickpea ideotype had higher yields than the commercial varieties and had 76% resemblance to Sonali. By incorporating key target traits and targeting the right environment, chickpea yields can be sustained under soil water limited conditions

Assessment of Conventional and Air-Jet Wheel Deflectors for Drag Reduction of The DrivAer Model

Aerodynamic drag is a large resistance force to vehicle motion, particularly at highway speeds. Conventional wheel deflectors were designed to reduce the wheel drag and, consequently, the overall vehicle drag; however, they may actually be detrimental to vehicle aerodynamics in modern designs. In the present study, computational fluid dynamics simulations were conducted on the notchback DrivAer model—a simplified, yet realistic, open-source vehicle model that incorporates features of a modern passenger vehicle. Conventional and air-jet wheel deflectors upstream of the front wheels were introduced to assess the effect of underbody-flow deflection on the vehicle drag. Conventional wheel-deflector designs with varying heights were observed and compared to 45◦ and 90◦ air-jet wheel deflectors. The conventional wheel deflectors reduced wheel drag but resulted in an overall drag increase of up to 10%. For the cases studied, the 90◦ air jet did not reduce the overall drag compared to the baseline case; the 45◦ air jet presented drag benefits of up to 1.5% at 35 m/s and above. Compared to conventional wheel deflectors, air-jet wheel deflectors have the potential to reduce vehicle drag to a greater extent and present the benefit of being turned off at lower speeds when flow deflection is undesirable, thus improving efficiency and reducing emissions

FAMILY DETERMINANTS OF TRANSITION FROM PRIMARY TO SECONDARY SCHOOLS IN MBOONI EAST DISTRICT, MAKUENI COUNTY, KENYA

Makueni County is affected by low transition rates, poor participation and completion rates. Access to secondary education in Mbooni-East district is also poor. The government of Kenya set a target of transition rate of 70% from primary to secondary schools from the current rate of 47%, and this is not achieved yet. The purpose of this study was therefore to investigate the family determinants of transition from primary to secondary schools in Mbooni-East district. Specifically this study sought to attain the following objectives: to establish the relationship between educational level of parents with transitions; determine the influence of parental income and transition; describe how the sibling position influenced transition and establish the measures which could be taken to enhance transition in the district. The results of this research were to generate useful information which would be used by educational planners and educational administrators to maintain efficient transitions in the district. Classical liberalism theory was used for the study. Descriptive survey research design was also used for this research as it was the most used method for collecting information on people’s attitudes, opinions, habits or any of the variety of educational or social issues. The study was conducted in secondary schools, in Kalawa division, Mbooni-East district, Makueni County. The target population was head teachers; Parents Teachers Association’s representatives (PTA’s) and all boys and girls in form one, in Kalawa division in the sampled schools. Probability sampling technique (systematic or interval sampling) was used because it removed the possibility of investigator bias. A sampling interval (k) and a random start were used to choose the sample. Research instruments were questionnaires for the head teachers, PTA’s and form ones and interview schedules for the PTA and the form ones in the division. Validity was done to check the accuracy of various skills and reliability done to determine the degree of coefficient of the theoretical concept. Piloting was done to check the accuracy of the research instruments. The questionnaires were filled and interview conducted in presence of the researcher at various different times. The data collected from the specific schools were analyzed through descriptive statistics. These are measures of central tendency such as the mean and percentages. The dependent variable was transition and the independent variables were parental level of education, parental income and sibling position on transition in Mbooni-East district. The findings showed a 45.6 percent of fathers’ who had reached form four and had a mean transition of 2.8 transition. Mothers’ who earned Kenya shillings 7500 formed 12.8 percent and a mean transition of 3.47. The results showed that transition was high to educated parents and low to illiterate parents, the sibling position favoured by transition were fifth borns who formed 20 percent and a mean transition of 2.8. Therefore, education is very necessary for the parents in order for them to educate their children; too, earning is also important for the parents in order to get money to educate their children. Lastly, every child should have equal opportunities to access secondary education, regardless of sibling position. Some measures which could be used to enhance transition in the district included building new schools and improving the existing ones, reduction of school fees and then government’s effort to sensitize the parents on the need and importance of supporting transition to all secondary schools in order to improve access to education in the district.  Article visualizations

Chickpea Abiotic Stresses: Combating Drought, Heat and Cold

Chickpea is an important legume providing dietary proteins to both humans and animals. It also ameliorates soil nitrogen through biological nitrogen fixation. Drought, heat and cold are important factors among abiotic stresses limiting production in chickpea. Identification, validation and integration of agronomic, physiological and biochemical traits into breeding programs could lead to increased rates of genetic gain and the development of better adapted cultivars to abiotic stress conditions. This chapter illustrates the effects of stresses on chickpea growth and development. It also reviews the various traits and their relationship with grain yield under stress and proposes recommendation for future breeding

Engineering Graphics Concept Inventory: Instrument Development and Item Selection

[EN] More reliable instruments need to be developed to assess curricula and measure student learning. It is important to ensure that students properly understand fundamental concepts, as scaffolding learning on a poor foundation can have a negative cascading effect. A concept inventory is an example of an instrument that aims to assess student learning and identifying their misconceptions. Such an instrument is typically comprised of an assessment whose items are prudently chosen to test understanding of a single concept per item. The result of this careful selection of items for the Engineering Graphics Concept Inventory resulted in a 30-question multiple choice instrument that can be used to identify deep-seated misconceptions and to assess course outcomes. This paper will outline the development of the Engineering Graphics Concept Inventory, focusing specifically on developing distractors and the selection process for the items in the instrument. The instrument will provide a means to assess and streamline curricula for engineering graphics educators. The research team would like acknowledge the support of NSF grants 1432280 and 1432288.http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Nabutola, K.; Steinhauer, H.; Nozaki, S.; Study, N.; Sadowski, M. (2018). Engineering Graphics Concept Inventory: Instrument Development and Item Selection. Editorial Universitat Politècnica de València. 1317-1324. https://doi.org/10.4995/HEAD18.2018.8196OCS1317132

THE CONTRIBUTION OF PARENTAL SOCIO-ECONOMIC STATUS ON PUPILS' KCPE PERFORMANCE IN MWEA-EAST DISTRICT, KIRINYAGA COUNTY, KENYA

The purpose of this study was to investigate parental socio-economic contribution and its implications on pupils’ Kenya Certificate of Primary Education (KCPE) performance in primary schools in Murinduko Zone, Mwea-East District. The objectives of the study included: to find out the extent to which the parents' level of income affects pupils performance, to analyze the effects of parents' level of education on pupils' KCPE performance in Murinduko zone, to investigate the manner in which the parents' political involvement affects pupils' KCPE performance in Murinduko Zone. The study employed descriptive research design while stratified random sampling was used to collect data. The data collection instruments were questionnaires, interview schedules and observations. The data was analyzed qualitatively and quantitatively using SPSS statistical package. The study was modeled by Abraham Maslow's hierarchy of need theory. The study established that most of the learners hailed from poor backgrounds and hence affected the KCPE performance. Most of the parents had attained only the primary level of education and were primary school drop-outs. Political wrangles between parents and the administration also affected the performance of pupils. Child labour is very prevalent and had a very great influence in the KCPE performance where children are exposed to it in order to subsidize family income. The main recommendations include; the government should continue offering Free Primary Education (FPE) and increase funding for building facilities like computer laboratories and libraries, public private partnership should be encouraged to increase resources in the primary education sector, the government should also consider giving stipends to pupils in hard to reach areas such as those in slums and marginalized zones this area so as to reduce drop-out rates and boost participation rates, need to enact and enforce legislation so as to curb child labour.  Article visualizations

PUPIL-TEACHER RATIO AND ITS IMPACT ON ACADEMIC PERFORMANCE IN PUBLIC PRIMARY SCHOOLS IN CENTRAL DIVISION, MACHAKOS COUNTY, KENYA

The objectives of this study were (a) to assess the impact of PTR on academic performance in national examinations in public primary schools (b) establish if ideal PTR exist in public primary schools as recommended by TSC, UNESCO and other international standards. (c) to identify the major challenges faced in the attainment of appropriate PTR in the public schools in the Division. (d) to determine whether PTR influences academic performance. The study targeted the 78 public primary schools in which a total of 24 schools were sampled for the study. Descriptive survey design was used as the research design for the study. Questionnaires were used in collecting data for the study. The analysis involved use of simple regression to determine whether PTR predicts performance in national examinations. The relationship between PTR and performance was worked out using Pearson’s product moment correlation coefficient R, the value of R calculated was -0.323. This negative correlation between the PTR and performance indicated that as PTR increases performance decreases and vice versa. A coefficient of determination R2 of 0.104 was obtained. This revealed that 10.4% of the performance is due to PTR while the remaining 89.6 % is due to other intervening factors or error in the independent variable. An Anova table was generated (p<0.05) which indicated that the regression model applied was significantly good enough in predicting the outcome variable. A regression model [scores = 260.8-7.60(PTR)] was generated that could be used to predict the outcome variable. The findings of the study revealed that PTR significantly influences performance of pupils in national examinations. The study recommended to all Education sector stakeholders to pay adequate attention to PTR since it affects performance of pupils in Primary Schools. It recommended to the government to employ more teachers to lower PTR and ease teacher workload. It also recommended to the government and the MOE to review the Education Act to enable schools admit pupils on basis of PTR to avoid over enrolment and congestion in classrooms.  Article visualizations

Differential proteolytic activation of the Bacillus thuringiensis Cry41Aa parasporin modulates its anticancer effect

Bacillus thuringiensis (Bt) is a gram positive spore forming bacterium which produces intracellular protein crystals toxic to a wide variety of insect larvae and is the most commonly used biological pesticide worldwide. More recently, Bt crystal proteins known as parasporins have been discovered, that have no known insecticidal activity but target some human cancer cells exhibiting strong cytocidal activities with different toxicity spectra and varied activity levels. Parasporin-3, also called Cry41Aa, has only been shown to exhibit cytocidal activity towards HL-60 (Human promyelocytic leukemia cells) and HepG2 (Human liver cancer cells) cell lines after being proteolytically cleaved. In order to understand this activation mechanism various mutations were made in the N-terminal region of the protein and the toxicity against both HepG2 and HL-60 cell lines was evaluated. Our results indicate that only N-terminal cleavage is required for activation and that N-terminally deleted mutants show some toxicity without the need for proteolytic activation. Furthermore we have shown that the level of toxicity towards the two cell lines depends on the protease used to activate the toxin. Proteinase K-activated toxin was significantly more toxic towards HepG2 and HL-60 than trypsin-activated toxin. N-terminal sequencing of activated toxins showed that this difference in toxicity is associated with a difference of just two amino acids (serine and alanine at positions 59 and 60 respectively) which we hypothesize occlude a binding motif

Evaluation of chickpea genotypes for resistance to Ascochyta blight (Ascochyta rabiei) disease in the dry highlands of Kenya

Chickpea (Cicer arietinum) is an edible legume grown widely for its nutritious seed, which is rich in protein, minerals, vitamins and dietary fibre. It’s a new crop in Kenya whose potential has not been utilized fully due to abiotic and biotic stresses that limit its productivity. The crop is affected mainly by Ascochyta blight (AB) which is widespread in cool dry highlands causing up to 100% yield loss. The objective of this study was to evalu- ate the resistance of selected chickpea genotypes to AB in dry highlands of Kenya. The study was done in 2 sites (Egerton University-Njoro) and Agricultural Training centre-ATC-Koibatek) for one season during long rains of 2010/2011 growing season. Thirty six genotypes from reference sets and mini-core samples introduced from ICR- SAT were evaluated. There were significant (P<0.001) differences in AB responses and grain yield performance in test genotypes in both sites. AB was more severe at Egerton-Njoro (mean score 5.7) than ATC-Koibatek (mean score 4.25), with subsequent low grain yield. Genotypes ICC7052, ICC4463, ICC4363, ICC2884, ICC7150, ICC15294 and ICC11627 had both highest grain yield in decreasing order (mean range 1790-1053 Kg ha-1) and best resist- ance to AB. Further evaluation is needed in other multi-locations and their use in breeding program determined especially because of their undesirable black seed color. Commercial varieties (LDT068, LDT065, Chania desi 1, and Saina K1) were all susceptible to AB, but with grain yield >1200 Kg ha-1. The findings of the study showed that chickpea should be sown during the short rains (summer) in the dry highlands of Kenya when conditions are drier and warmer and less favorable for AB infection. However yield could be increased by shifting the sowing date from dry season to long rain (winter) thus avoiding terminal drought if AB resistant cultivars with acceptable agronomic traits could be identified