Advances in Research and Reviews

Twin-screw compressor is a kind of rotary positive displacement pump with excellent performance. Due to its advantages of reliable operation, high efficiency, low noise and multiphase mixed transportation, it has been widely used in the fields of energy power, biomedicine, refrigeration and air conditioning, petrochemical industry, industrial construction and other rudder fields. In recent decades, although the study of screw compressor is more in-depth, but the three-dimensional flow field simulation design of twin screw compressor still needs breakthrough. In this paper, 3d flow characteristics of twin screw compressor are studied based on CFD numerical simulation. In this paper, CFD software is used for numerical simulation of twin screw compressor, and the distribution of pressure cloud, temperature cloud and velocity cloud of internal flow field is obtained.

Potato (Solanum tuberosum L.) is an important food and export crop in central highlands of Oromia region. The limiting macro and micronutrients were identified for the production of potato crops in Boneya districts. The rates of these nutrients for high potato yield and disease resistance are not yet determined. Therefore, this research was conducted to determine the effect of blended NPSB fertilizer rates on yield and yield related traits of potato varieties at Boneya Kebele, central highlands of Oromia region. The experiment was conducted as factorial combination of seven levels of blended NPSB fertilizer rates (0, 50, 100, 150, 200, 250, 300 kg ha-1) and three potato varieties (Belete, Gudane and Jalane) in Randomized Complete Block Design with three replications. The results of the study revealed that variety and blended NPSB fertilizer had significant effect on crop phenology, growth, tuber yield and yield components except proportion of medium size tubers which is not influenced by the two main factors. Blended NPSB fertilizer had nonsignificant effect on days to 50% emergence, number of main stem/hill and proportion of large size tubers. Variety and blended NPSB fertilizer interacted to influence days to 50% flowering, average tuber weight (g), average tuber number, unmarketable tuber yield, and proportion of small, medium and large size tubers. The highest marketable tuber yield (30.74 t ha-1) and total tuber yield (32.16 t ha-1) was obtained by the application of NPSB fertilizer at highest rate of 300 kg ha-1 which was followed by the application of 250 kg ha-1. Gudane (29.52 t ha-1) and Belete (29.48 t ha-1) produced significantly higher marketable tuber yield than Jalane variety. Therefore, growing of the two varieties at highest rates of blended NPSB fertilizer could be recommended in the study area for producers, because of gives higher marketable yield.

In beekeeping, honeybee queen has significant effect on several production and productivity traits. Artificial queen rearing techniques are among the important approaches to help to produce of queens with desirable characters in beekeeping. The aim of the present review of literature is to assess progress of past research and identify gaps in artificial honeybee queen rearing.In Ethiopia, several studies have been conducted on various aspects of honeybee queen rearing. A number of queen rearing methods were evaluated and recommended for use. However, little or nothing is known on other important attributes of honeybee queen rearing like queen quality and fecundity.It is very much important for the future research works to focus 1st on how to be very sure that honeybee queen rearing is possible with all races of Ethiopian honeybee and 2nd test the produced queens on their quality and fecundity aspects.

Fungi are critical agents of the global carbon cycle, however, our ability to link fungal community composition to ecosystem functioning is constrained by a limited understanding the wood decomposition rates of fungus. Here we examined the wood decomposition rate of fungus and the impact of fungal community diversity on the wood decomposing. To understand the relationship between the wood decomposition rate and the traits of fungi, we introduced 37 types of fungus into the wood decomposition system and set the growth rate and moisture tolerance of fungus as the explanatory variables. In addition, we constructed the competition, parasitic and symbiotic model based on Malthus-block growth comprehensive to analyze and predict the interactions between different fungus. The entropy weight-TOPSIS model was established to understand the biodiversity of fungus and obtain the relative dominance degree which can reflect the advantages and disadvantages of different fungus. The ARIMA model was used in five different environments to predict the impact of fungal community diversity on the overall efficiency of wood decomposing. Our research can not only help us to better understand the fungus community, but also significant for improving the quality of climate and the carbon cycle.

Aiming at the conceptual design stage of semi-submersible support platform, the optimal primary scale scheme is designed. Latin hypercube design is adopted to sample the sample space. At the same time, SESAM software is used for parametric modeling based on sample point parameters to obtain the model of all schemes. According to the existing data of semi-submersible platforms, the main scale constraints of platforms are determined, and the mathematical model with the minimum heave, trim and roll response as the objective function is established. The multi-island genetic algorithm was used to optimize the main scale of the supporting platform model, and the scheme with the highest stability and suitable displacement was selected. The results show that the model and algorithm are feasible, and the smallest scale scheme of each response can be obtained under the constraint conditions. The multi-island genetic algorithm is proposed to optimize the primary scale of the platform, which has a strong reference value for the determination of the primary scale scheme in the conceptual design stage of the platform.

The use of medicinal plants and probiotics has recently gained interest since the ban on the use of antibiotics as growth promoters by the European Union in 2006. They are new alternatives to bridge the gap between food safety and production. Medicinal plants are cheaper and loaded with several minerals, vitamins and phytochemicals such as: alkaloids, saponin, flavonoids, phenols, tannins etc. which allows them to perform multiple biological activities. Probiotics on the other hand, repopulates the gastro intestinal tracts (GIT) with beneficial bacteria which controls the action of pathogens and control their population, thereby reducing mortality and improving general performance of an animal.

This paper mainly solved the problem of predicting the time required for vehicles to pass through congested roads. In order to obtain more accurate prediction time, a Kalman prediction model based on multiple linear regression was established in this paper. Taking the 2008 Yanan elevated road in Shanghai as an example, the measured data in this section was collected from the traffic measured data sharing network, and the above model was used to obtain good prediction results. As an improvement, we used BP neural network instead of multiple linear regression to make the prediction result more in line with the actual situation.

The study was designed to evaluate the carcass quality, nutrient retention and caeca microbial population of broiler chicks administered Daniellia oliveri leaf extract (DOE) as an antibiotic alternative. A total of 250 – one-day-old broiler chicks (Ross 308) were allocated to five treatments in a completely randomized design and each treatment group was further sub-divided into five replicates containing ten (10) birds each. Treatment 1 (Control) was given 1.20 g/ liter of Neomycin in water, while treatments 2, 3, 4 and 5 were given DOE at 10 ml, 20 ml, 30 ml and 40 ml/liter of water respectively. Clean feed and water were supplied ad libitum throughout the experiment which lasted for 56 days. Data collected were used to determine the carcass quality, nutrient retention and caeca microbial population. Highest dressing percentage was recorded for birds in T5 (70.0%) followed by T4 (69.08 %), T3 (67.18 %), T2 (67.44 %) and T1 (65.0 %) respectively (P

To comprehensively measure the effect of football team cooperation, this paper established a football team performance evaluation model and takes the performance of Everton F.C. in 2017 to 2018 season as an example. We selected 12 indicators from three aspects and use hierarchical clustering to divide the performance into four levels: very successful, relatively successful, unsuccessful and very failed. Then, we evaluated the performance of the team’s changes and focus on the opponent’s strategy indicators to analyze its impact. It is found that the reason for most of the failed games is that the team is affected by the away effect, the intra-team cooperation is not dominant and the opponent’s ability is strong, resulting in low CPI scores. At the end of the season, the influence of the opponent strategy on team performance becomes stronger and stronger.

This study critically inspected the Mangima conflict resolution within Gumuz society in Metekel Zone, Bineshangul Gumuz National Regional state, Ethiopia. Mangima institution played a significant role in resolving conflicts as well as contributed to the establishment of peaceful relations within Gumuz communities in each districts of region. Gumuz are one of the indigenous peoples have settled in the region. Their conflict was instigated by the problems related to marriage, abducting girls, elopement, adultery, incest, belief in evil eye, Gäfia (Witch doctor), deliberate killings for heroism, competitions over the use of land resources, insults and failure to pay back debts. The Gumuz inhabited areas of Metekel was purposively selected for this study. The data was collected using key informants interview and focus group discussion. Gumuz elders and local leaders that appointed during the regime were independently interviewed and focus group discussions attended by five groups through 20 peoples in each group on the issues of conflict generating practices and the role Mangima conflict resolution within Gumuz communities. The sources are critically collected, examined and then analyzed. The legitimacies of the sources are cross-checked one against the other.