Research on drilling parameters of engine-powered auger ice drill

Drilling operations in polar regions and mountainous areas are complicated by nature of the extreme environment. Yet conventional rotary drilling technologies can be used to drill ice for scientific samples and oth- er research. Due to such reasons as power consumption and weight complications, it is hard to apply a conven- tional rotary drilling rig for glacial exploration. Use of small, relatively lightweight, portable engine-powered drilling systems in which the drill lifting from the borehole is carried by the winch. It is reasonable enough for near-surface shallow ice-drilling down to 50 m. Such systems can be used for near-surface ablation-stakes in- stallation, also temperature measurements at the bottom of active strata layer, revealing of anthropogenie pollu- tion, etc. The specified used in this research is an auger ice drill powered by a gasoline engine. At this stage, it is crucial to choose effective drilling parameters such as weight on bit （WOB） and drill bit rotation rate. Sen- sors equipped on the rig have measured the main parameters of the drilling process, such as drill speed, WOB, drill rotation speed, torque and temperature. This paper addresses research on drilling parameters of engine powered auger ice drill and supplies some recommendations for optimization of any ice-core drilling process.

RELATIONS OF ENDOTHELIAL FUNCTION AND BLOOD FLOW IN BRACHIAL ARTERY AND CORONARY ARTERY

Objective:To determine the relations between endothelium-dependent vasodilator function and blood flow in the brachial and coronary arteries in patients with suspected coronary artery disease.Methods:Twenty-eight patients with suspected coronary artery disease underwent brachial artery endothelial function test by using high-resolution B-mode ultrasound before coronary angiography(CAG)and coronary flow reserve(CFR)test by using intracoronary Doppler technique.The correlation of coronary artery dilatation induced by an increase in blood flow after intracoronary adenosine infusion and brachial artery flow-mediated dilatation(FMD) following reactive hyperemia was evaluated.The relation between the change of brachial artery blood flow and CFR was also studied.Results:There was a positive correlation between brachial FMD and percent change of coronary diameter after adenosine infusion(12.50%±9.35% vs 11.38%±7.55%,r=0.425,P=0.02).There was also a weak negative relation between brachial flow change following reactive hy-peremia and CFR(r=-0.397,P=0.04).Conclusion:There is a correlation between the coronary endo-thelial function and the CFR by ultrasonic determination of brachial flow changes following reactive hyperemia.

Engine Noise Prediction by Using Multi-body Simulation

Abstract： This paper presents a coupled multi-body and FEM （finite element method）-BEM （boundary element method） methodology used to carry out a comprehensive NVH （noise, vibration and harshness） investigation of a four-cylinder internal combustion engine prototype. Firstly, a MBDS （multi-body dynamic simulation） of the internal combustion engine has been carried out, at a defined operating condition, in order to determine the excitation force of the powertrain exciting the cylinder block. In this way, the dynamics of the engine powertrain have been described taking into account both the effects of the gas forces of the combustion process and the inertia forces of the moving parts. Afterwards, the cylinder block excitation forces have been used to evaluate the engine block vibrations and to predict the external noise radiated with both the well-known ATV （acoustic transfer vectors） and MATV （modal acoustic transfer vectors） methodologies at a distance of 1 m from the engine, according to the standard ISO 3744. The dynamics of the engine powertrain and its vibro-acoustic behaviour have been described using LMS （learning management system） Engineering Innovation Virtual.Lab tools.

Motivational Practices in Foreign Language Teaching:From the Perspective of Self-Determination Theory

This quantitative-oriented study investigates junior middle school EFL teachers’beliefs about motivational practices in the language teaching process.Grounded in self-determination theory,the study examined teachers’beliefs in three basic psychological needs(relatedness,competence and autonomy)and the effect of their teaching experience on these beliefs.Data were obtained from 84 Chinese junior middle school English teachers through a questionnaire.Results suggested that teachers recognized motivational practices for relatedness and competence satisfaction while showing relatively low recognition of a few motivating practices for autonomy satisfaction.Teaching experience was found to have no influence on teachers’conception of needs-related motivational practices.Findings reveal that traditional activities like collective lesson preparations may have a negative influence on teachers’beliefs about motivational practices.They also present the necessity for adjustments on educational regulations,and for modern professional training to help teachers understand students’basic psychological needs,and to encourage new ideas to bolster students’intrinsic motivation for language learning.

The Impact of Flexible Element Inside of Intake Canal on Kinematics of Load in Combustion Chamber

The results of analysis of technical possibilities to increase engine efficiency were presented in this article. This problem was connected with kinematics properties of air inflow to the combustion chamber. The possibilities of intake airflow modulation have a positive impact on combustion process, level of engine usable parameters and emission. This issue was presented on the results of experimental research. Results of baseline research gave information about the flow resistance. On the basis of results of experimental research, conclusions were formulated.

调动学生内在的积极因素 提升学生的语文素养

语文教师要多一双观察的眼睛,让每个孩子都能够在语文的学习中善于捕捉,在细节处见真情,让他们乐于阅读,爱上写作,更乐于表达,这样学生的学习才能够做到轻松自如,从而促进整体能力的提升。

LESS SUCCESSFUL STUDENTS' MOTIVATION AND THEIR TEST PERFORMANCES

Through questionnaire investigation, three major motivation types have been identified in less successful second year students (judged by the state exam CET4) in Hainan University: type A — integrative/intrinsic motivation (interest in culture and language), type B — job-related motivation (learning for better jobs), and type C — test-oriented motivation (learning to pass tests). Students with instrumental motivation (types B & C) far out-number those with integrative motivation (type A). Significant differences in test performance are found between type A and type C, and type B and type C. No significant difference is found between the test performance of type A students and that of type B students.

Study on pneumatic-fuel hybrid system based on waste heat recovery from cooling water of internal combustion engine

The paper proposes a novel pneumatic-fuel hybrid system,which combines a traditional internal combustion engine(ICE)and a pneumatic engine.One important merit of this concept is that the system can recover waste from cooling water of internal combustion engine to optimize the working process of pneumatic engine,and thus to improve the entire efficiency of the hybrid system.Meanwhile,energy-saving effect due to lower cooling fan power can be achieved on ICE by waste heat recovery of pneumatic engine.Based on thermodynamic analysis,an experimental system is designed and established for verification.The experimental results show that the performance of pneumatic engine is improved when the waste heat recovery concept of the hybrid system is applied.Then an application example on a 4-cylinder engine is analyzed and discussed using numerical simulation.The results show that the fan power of the ICE cooling system can be saved up to 50%by applying the hybrid system.Considering the appreciable improvements on the energy efficiency with only limited system modifications when the concept is applied to traditional ICE based power systems,the proposed hybrid concept has the potential to serve as an alternative technology aiming for energy saving and emission reduction.

Fluid dynamic modeling of junctions in internal combustion engine inlet and exhaust systems

The modeling of inlet and exhaust systems of internal combustion engine is very important in order to evaluate the engine performance.This paper presents new pressure losses models which can be included in a one dimensional engine simulation code.In a first part,a CFD analysis is made in order to show the importance of the density in the modeling approach.Then,the CFD code is used,as a numerical test bench,for the pressure losses models development.These coefficients depend on the geometrical characteristics of the junction and an experimental validation is made with the use of a shock tube test bench.All the models are then included in the engine simulation code of the laboratory.The numerical calculation of unsteady compressible flow,in each pipe of the inlet and exhaust systems,is made and the calculated engine torque is compared with experimental measurements.

Intrinsic and Extrinsic Value for English Learning: Mediation Effects of SelfEfficacy in Chinese EFL Context

The present study examined how students＇ intrinsic and extrinsic value promotes their foreign language proficiency via the mediation effect of self-efficacy beliefs. A total of 1,036 Chinese eighth graders answered an English proficiency test and questionnaires assessing motivational beliefs. Structural equation modelling results with bootstrapping procedures revealed that intrinsic value can directly and indirectly influence foreign language proficiency via partial mediation effect of self-efficacy while extrinsic value can only directly influence foreign language proficiency with a small magnitude. Moreover, there is no gender difference in the mediation model. Our findings suggested that intrinsic value can help students improve foreign language proficiency by improving their self-efficacy beliefs. The findings contribute to the documents of self-determination theory and hold substantive theoretical and practical implications for foreign language teachers.

Development of performance and combustion system of Atkinson cycle internal combustion engine

The application of hybrid vehicle is a practical technical solution to the energy shortage and the environmental pollution.The internal combustion engine(ICE)plays a key role in the development of the hybrid vehicle.Based on the requirements of the hybrid vehicle and the characteristic of Atkinson cycle,a set of designing methods for the Atkinson cycle gasoline engine is presented through the analysis of the optimized matching for the compression ratio,valve timing and the combustion chamber.The designing method has been verified by the bench test and the results show that the fuel consumption can be improved by12%–15%with the reduction of the low speed torque by 10%,and the low fuel consumption region in the fuel map extends significantly with the rated power almost keeping constant.It may be of great reference for the development of hybrid vehicle technology in China.