This study investigated the capacity building needs for manual and computer assisted teaching of pattern drafting for entrepreneurship in tertiary institutions in Nigeria.The study was conducted and guided by two rese...This study investigated the capacity building needs for manual and computer assisted teaching of pattern drafting for entrepreneurship in tertiary institutions in Nigeria.The study was conducted and guided by two research questions and two hypotheses.This study adopted an ex-post facto research design.The population for the study consisted of 131 Home Economics lecturers from the Universities,Polytechnic,and Colleges of Education in South East Nigeria.The entire population was studied because of its manageable size,hence there was no sampling.The results of this study showed that the Home Economics lecturers are competent in drafting patterns using manual method.Technical skills required for lecturers of Home Economics to advance from manual to computer-assisted teaching of pattern drafting were identified.They include ability to grade patterns,ability to use software packages,and ability to discuss procedures of pattern drafting among others.Based on the findings,it was recommended among others that computer assisted teaching of pattern drafting should be incorporated and applied by Home Economics lecturers to ensure that students acquire technical skills that will enable them to enter into entrepreneurship.展开更多
This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state an...This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.展开更多
Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study,...Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.展开更多
The combing process of gill machine is an important link in the wool spinning technology.Inorder to improve the quality of products,it is necessary to study the new autoleveling device whichuses the modern control the...The combing process of gill machine is an important link in the wool spinning technology.Inorder to improve the quality of products,it is necessary to study the new autoleveling device whichuses the modern control theory and microcomputer science.We have to set up a mathematicalmodel for object:As the woolen yarns (both input and output) are complex random process,it issuitable for CARMA (controlled autoregressive-moving average) to describe the object by meansof time series analyses of models.展开更多
The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the fr...The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the friction behavior of fibers,and the difference is largely responsible for the "stick-slip" motion of fibers which causes the drafting waves during drafting.In this paper,it's expected that when a high frequency undulating wave is imposed on the fiber strand in the drafting zone of roller system,the friction among fibers is dominated by the dynamic friction rather than the static friction,and thus the "stick-slip" motion will be eliminated.As a result,the fiber binding effect causing drafting waves can be significantly reduced.This hypothesis is verified by an experiment,and it can be applied in developing new spinning drafting device.展开更多
The goal of this paper is to provide an approach to investigate the variation of fiber quantity in a certain cross-section of the drafting zone. This model with discrete-event simulation( DES)method was presented to s...The goal of this paper is to provide an approach to investigate the variation of fiber quantity in a certain cross-section of the drafting zone. This model with discrete-event simulation( DES)method was presented to simulate the dynamic drafting process. This model described the behavior of individual fibers,which was divided into four phases and simulated by corresponding modules. Three sets of processing conditions in industry were simulated and demonstrated the applications of this model. The comparison between experiments and simulation results could also validate this model. This model could be used to simulate various drafting process with appropriate drafting settings.展开更多
Alattice laser drafting system of world standard was recently developed by the Beijing Kaisheng Electronic Technology Co. Ltd. It marks Beijing getting the latest laser drafting technology in precision of printed circ...Alattice laser drafting system of world standard was recently developed by the Beijing Kaisheng Electronic Technology Co. Ltd. It marks Beijing getting the latest laser drafting technology in precision of printed circuit diagram films and liquid crystal display (LCD) diagram films. The quality of printed circuits determines the展开更多
Pressure applied on the top roller of drafting zone is a vital factor on which the quality of ultimate yarn depends. Drafting zone is needed to reduce the mass per unit length of input material. Appropriate contact of...Pressure applied on the top roller of drafting zone is a vital factor on which the quality of ultimate yarn depends. Drafting zone is needed to reduce the mass per unit length of input material. Appropriate contact of top rollers with bottom rollers is necessary to ensure proper drafting. In this paper, the effects of different front top roller pressure of drafting zone on the quality of 20Ne cotton-flax blended yarns (C:L = 45:55) were studied. It was observed that a higher pressure value gives a lower co-efficient of mass variation, imperfections, hairiness and higher evenness, tenacity, elongation properties.展开更多
This paper puts forward a new drafting system of the rubbed roving frame, which consists of a nine-link gear, two slipping gears. It has brought forward a new design method of the nine-link gear and the slipping gears...This paper puts forward a new drafting system of the rubbed roving frame, which consists of a nine-link gear, two slipping gears. It has brought forward a new design method of the nine-link gear and the slipping gears, and set up approximate formulas for modification coefficients of gears for the first time. And the principles of transmitting rate designing for the system are given. The calculating results demonstrate that the new design method satisfies the demands of processing technology. This mechanism has been used successfully in the kind of rubbed roving frame.展开更多
The drafting of the arbitration clause is often done late or at the same time as the parties are finalizing the different parts of a contract.The parties may be far away from their offices,draft the arbitration clause...The drafting of the arbitration clause is often done late or at the same time as the parties are finalizing the different parts of a contract.The parties may be far away from their offices,draft the arbitration clause themselves or they ask for an arbitration clause to be sent to out to them by mail.And mistakes may arise which can have展开更多
Today telex and cable are two important means usod in communication with customors abroad. In telex,as it is not chargod by the number of words but by the minute,more words can be used to express our idea,so it is les...Today telex and cable are two important means usod in communication with customors abroad. In telex,as it is not chargod by the number of words but by the minute,more words can be used to express our idea,so it is less difficult for our students to learn,while in cable we,in order to save money,展开更多
The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breakin...The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breaking force, breaking elongation and costs. The experiment with different pre-drafting multiple isdesigned. The effects of pre-drafting multiple on yarn properties are evaluated by fuzzy mathematical decision.3.3 is the optimum pre-drafting multiple for 14.6tex +40D spandex/cotton core-spun yarns. At this multiple,the spandex content is proper and the spandex core is less prone to breakage. The cotton fibers wrap spandex more closely and transfer more frequently between inside and outside.展开更多
基金supported by the Tertiary Education Trust Fund(TETFund)through Institution Based Research(IBR)intervention(grant reference number:TETF/DR&D/CE/COE/NSUGBE/IBR/2019/VOL.1).
文摘This study investigated the capacity building needs for manual and computer assisted teaching of pattern drafting for entrepreneurship in tertiary institutions in Nigeria.The study was conducted and guided by two research questions and two hypotheses.This study adopted an ex-post facto research design.The population for the study consisted of 131 Home Economics lecturers from the Universities,Polytechnic,and Colleges of Education in South East Nigeria.The entire population was studied because of its manageable size,hence there was no sampling.The results of this study showed that the Home Economics lecturers are competent in drafting patterns using manual method.Technical skills required for lecturers of Home Economics to advance from manual to computer-assisted teaching of pattern drafting were identified.They include ability to grade patterns,ability to use software packages,and ability to discuss procedures of pattern drafting among others.Based on the findings,it was recommended among others that computer assisted teaching of pattern drafting should be incorporated and applied by Home Economics lecturers to ensure that students acquire technical skills that will enable them to enter into entrepreneurship.
基金Key Laboratory of Low-Grade Energy Utilization Technologies and Systems(LLEUTS-2023001)the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1470).
文摘This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.
文摘Ventilation is one of the factors contributing to energy consumption in buildings and food preservation. The solar chimney proves to be an alternative for reducing conventional energy consumption. Thus, in this study, the performance of a solar chimney with two active faces for thermally drawing air from a chamber for preserving agri-food products was evaluated. These performances were experimentally assessed through data measurements: temperatures and velocities within the chimney, and their analysis using Excel and MATLAB. The obtained results were compared with those from literature to verify their validity. From this study, it is found that the maximum temperature at the chimney outlet reaches 49.4˚C with an average value of 43.7˚C. Additionally, the heating evolution of the chimney air presents four (04) identical phases in pairs, reflecting the chimney’s operation throughout day. The temperature difference between the outlet and inlet of the chimney reaches a maximum of 17˚C with an average of 12.6˚C. Regarding airflow, the maximum air velocity at the chimney outlet is 0.8 m/s, and the average velocities have consistently been greater than or equal to 0.46 m/s. Thus, it can be concluded that the solar chimney is capable of providing ventilation for the preservation chamber through thermal draft.
文摘The combing process of gill machine is an important link in the wool spinning technology.Inorder to improve the quality of products,it is necessary to study the new autoleveling device whichuses the modern control theory and microcomputer science.We have to set up a mathematicalmodel for object:As the woolen yarns (both input and output) are complex random process,it issuitable for CARMA (controlled autoregressive-moving average) to describe the object by meansof time series analyses of models.
基金National Natural Science Foundation of China(No.50775034)
文摘The mechanism of the staple yarn's drafting waves during roller drafting is analyzed in this paper.It's concluded that the dynamic friction coefficient is greater than the static friction coefficient on the friction behavior of fibers,and the difference is largely responsible for the "stick-slip" motion of fibers which causes the drafting waves during drafting.In this paper,it's expected that when a high frequency undulating wave is imposed on the fiber strand in the drafting zone of roller system,the friction among fibers is dominated by the dynamic friction rather than the static friction,and thus the "stick-slip" motion will be eliminated.As a result,the fiber binding effect causing drafting waves can be significantly reduced.This hypothesis is verified by an experiment,and it can be applied in developing new spinning drafting device.
基金the Key Grant Project of Ministry of Education of the People’s Republic of China through Project,China(No.113027A)the Fundamental Research Funds for the Central Universities,China
文摘The goal of this paper is to provide an approach to investigate the variation of fiber quantity in a certain cross-section of the drafting zone. This model with discrete-event simulation( DES)method was presented to simulate the dynamic drafting process. This model described the behavior of individual fibers,which was divided into four phases and simulated by corresponding modules. Three sets of processing conditions in industry were simulated and demonstrated the applications of this model. The comparison between experiments and simulation results could also validate this model. This model could be used to simulate various drafting process with appropriate drafting settings.
文摘Alattice laser drafting system of world standard was recently developed by the Beijing Kaisheng Electronic Technology Co. Ltd. It marks Beijing getting the latest laser drafting technology in precision of printed circuit diagram films and liquid crystal display (LCD) diagram films. The quality of printed circuits determines the
文摘Pressure applied on the top roller of drafting zone is a vital factor on which the quality of ultimate yarn depends. Drafting zone is needed to reduce the mass per unit length of input material. Appropriate contact of top rollers with bottom rollers is necessary to ensure proper drafting. In this paper, the effects of different front top roller pressure of drafting zone on the quality of 20Ne cotton-flax blended yarns (C:L = 45:55) were studied. It was observed that a higher pressure value gives a lower co-efficient of mass variation, imperfections, hairiness and higher evenness, tenacity, elongation properties.
文摘This paper puts forward a new drafting system of the rubbed roving frame, which consists of a nine-link gear, two slipping gears. It has brought forward a new design method of the nine-link gear and the slipping gears, and set up approximate formulas for modification coefficients of gears for the first time. And the principles of transmitting rate designing for the system are given. The calculating results demonstrate that the new design method satisfies the demands of processing technology. This mechanism has been used successfully in the kind of rubbed roving frame.
文摘The drafting of the arbitration clause is often done late or at the same time as the parties are finalizing the different parts of a contract.The parties may be far away from their offices,draft the arbitration clause themselves or they ask for an arbitration clause to be sent to out to them by mail.And mistakes may arise which can have
文摘Today telex and cable are two important means usod in communication with customors abroad. In telex,as it is not chargod by the number of words but by the minute,more words can be used to express our idea,so it is less difficult for our students to learn,while in cable we,in order to save money,
文摘The factors that influence the properties of spandex/cotton core-spun yarns are introduced. The pre-drafting multiple of spandex is an important parameter that influences the yarn properties such as elasticity,breaking force, breaking elongation and costs. The experiment with different pre-drafting multiple isdesigned. The effects of pre-drafting multiple on yarn properties are evaluated by fuzzy mathematical decision.3.3 is the optimum pre-drafting multiple for 14.6tex +40D spandex/cotton core-spun yarns. At this multiple,the spandex content is proper and the spandex core is less prone to breakage. The cotton fibers wrap spandex more closely and transfer more frequently between inside and outside.
