Learning has come a long way from the conventional blackboard that marked the earlier decades to the new age Blackboard Collaborate which enables learners to work and learn in a collaborative online environment. Virtu...Learning has come a long way from the conventional blackboard that marked the earlier decades to the new age Blackboard Collaborate which enables learners to work and learn in a collaborative online environment. Virtual classrooms, especially with learners sharing in academic workload on portals such as Google Docs, have arrived as a natural development of the ICT （In Circuit Tester） wave. In addition to offering ample scope for peer interaction, Blackboard Collaborate gives learners the electronic environment they are most familiar with and keeps them updated with the latest educational tools. However, for it to succeed, the perception of the teachers is a factor that needs close scrutiny before this tool can be incorporated into the system. The aim of this paper is to investigate the perceptions of teachers at Qassim University, KSA （Kingdom of Saudi Arabia） towards the inclusion of Blackboard Collaborate into the teaching-learning environment, and its efficacy as a learning tool in the university＇s EFL （English as a Foreign Language） situation.展开更多
Uneven roads surface can be observed on bituminous pavements. This is due to moving loads and climate conditions. If the observed deformations exceed the elastic limit, important damages can occur, so new materials ar...Uneven roads surface can be observed on bituminous pavements. This is due to moving loads and climate conditions. If the observed deformations exceed the elastic limit, important damages can occur, so new materials are used to improve the stiffness modulus of bituminous mixtures. To achieve this, a modified bituminous concrete by addition of the PR PLAST Sahara （produced by PR industries and PLAST for Plastic） mainly used in arid region has been studied. The use of this additive at various percentages 0.1, 0.3, 0.6 and 0.9 by weight of bituminous concrete has been investigated to determine its stiffness modulus. An experimental design using the Taguchi tables has been elaborated to reduce the number of tests. Marshall and NAT （Nottingham asphalt tester） tests have been carried out, and a mathematical model of the stiffness modulus has been proposed.展开更多
We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacem...We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.展开更多
文摘Learning has come a long way from the conventional blackboard that marked the earlier decades to the new age Blackboard Collaborate which enables learners to work and learn in a collaborative online environment. Virtual classrooms, especially with learners sharing in academic workload on portals such as Google Docs, have arrived as a natural development of the ICT （In Circuit Tester） wave. In addition to offering ample scope for peer interaction, Blackboard Collaborate gives learners the electronic environment they are most familiar with and keeps them updated with the latest educational tools. However, for it to succeed, the perception of the teachers is a factor that needs close scrutiny before this tool can be incorporated into the system. The aim of this paper is to investigate the perceptions of teachers at Qassim University, KSA （Kingdom of Saudi Arabia） towards the inclusion of Blackboard Collaborate into the teaching-learning environment, and its efficacy as a learning tool in the university＇s EFL （English as a Foreign Language） situation.
文摘Uneven roads surface can be observed on bituminous pavements. This is due to moving loads and climate conditions. If the observed deformations exceed the elastic limit, important damages can occur, so new materials are used to improve the stiffness modulus of bituminous mixtures. To achieve this, a modified bituminous concrete by addition of the PR PLAST Sahara （produced by PR industries and PLAST for Plastic） mainly used in arid region has been studied. The use of this additive at various percentages 0.1, 0.3, 0.6 and 0.9 by weight of bituminous concrete has been investigated to determine its stiffness modulus. An experimental design using the Taguchi tables has been elaborated to reduce the number of tests. Marshall and NAT （Nottingham asphalt tester） tests have been carried out, and a mathematical model of the stiffness modulus has been proposed.
基金the National Science Foundation of China (No.50745020).
文摘We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.
