5,666 research outputs found
Complementary-MOS binary counter with parallel-set inputs
Metal oxide semiconductor four-stage binary counter contains reset capability as well as four parallel-set inputs gated in by a logic signal. Parallel-set inputs permit setting the counter into any of sixteen possible states
Design and development of a digital subsystem employing n and p-channel Mos Fet's in complementary circuits in an integrated circuit array Final report, 1 May 1967 - 30 Apr. 1968
Digital subsystem design and development employing n-channel and p-channel in MOS FET units in complimentary circuits in integrated circuit arra
Reconstruction of a three-dimensional, transonic rotor flow field from holographic interferogram data
Holographic interferometry and computerized aided tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia view field near the model rotor blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting the fringe order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in several planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three dimensional transonic rotor flow studies
Transonic rotor flow-measurement technique using holographic interferometry
Holographic interferometry is used to record interferograms of the flow near a hovering transonic rotor blade. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia. view field near the model rotor blade tip operating at a tip Mach number of 0.90. The experimental procedure is presented and example interferograms recorded in the rotor's tip path plane. In addition, a method currently being pursued to obtain quantitative flow information using computer assisted tomography (CAT) with the holographic interferogram data, is outlined
Interactive solution-adaptive grid generation
TURBO-AD is an interactive solution-adaptive grid generation program under development. The program combines an interactive algebraic grid generation technique and a solution-adaptive grid generation technique into a single interactive solution-adaptive grid generation package. The control point form uses a sparse collection of control points to algebraically generate a field grid. This technique provides local grid control capability and is well suited to interactive work due to its speed and efficiency. A mapping from the physical domain to a parametric domain was used to improve difficulties that had been encountered near outwardly concave boundaries in the control point technique. Therefore, all grid modifications are performed on a unit square in the parametric domain, and the new adapted grid in the parametric domain is then mapped back to the physical domain. The grid adaptation is achieved by first adapting the control points to a numerical solution in the parametric domain using control sources obtained from flow properties. Then a new modified grid is generated from the adapted control net. This solution-adaptive grid generation process is efficient because the number of control points is much less than the number of grid points and the generation of a new grid from the adapted control net is an efficient algebraic process. TURBO-AD provides the user with both local and global grid controls
The value(s) in shadow education: re-visiting pedagogy and learning
Panel: The value and values of comparative research on shadow education: Methodological perspectives from researchers in Hong Kong and Mainland Chinaไธป้ก: ๆฏ่ผๆ่ฒไน้๏ผๅฏฉๆ่ๅ็ปTheme: Exploring the value and values of comparative educationThis session comprises studies on shadow education in Hong Kong and Guangzhou under the education reform climate which places pedagogical focus on student-centred learning, learner autonomy and all-round development of students. However, the studies reveal that shadow education tends to promote contradictory values for profit-making assurance. Private tutors in tutorial centres usually adopt a one-way lecturing style with exclusive focus on examination preparation which appeals to learners' superficial needs. This may discourage learner autonomy and, more seriously, devalue the ethos of teaching and learning intended for the reforms in mainstream education. Issues for critical discussion: 1. What kinds of values are promoted under the education reform in mainstream schooling? How are they similar or different from those promoted under shadow education? 2. What do students, parents, teachers, tutors, school principals, and government officials think about the different directions the two systems are going? 3. What should the government do if the two systems are going in different directions? 4. How can learners' autonomy develop amidst the trend of efficiency in exam preparation?postprin
Interactive grid generation for turbomachinery flow field simulations
The control point form of algebraic grid generation presented provides the means that are needed to generate well structured grids for turbomachinery flow simulations. It uses a sparse collection of control points distributed over the flow domain. The shape and position of coordinate curves can be adjusted from these control points while the grid conforms precisely to all boundaries. An interactive program called TURBO, which uses the control point form, is being developed. Basic features of the code are discussed and sample grids are presented. A finite volume LU implicit scheme is used to simulate flow in a turbine cascade on the grid generated by the program
Dynamics of local grid manipulations for internal flow problems
The control point method of algebraic grid generation is briefly reviewed. The review proceeds from the general statement of the method in 2-D unencumbered by detailed mathematical formulation. The method is supported by an introspective discussion which provides the basis for confidence in the approach. The more complex 3-D formulation is then presented as a natural generalization. Application of the method is carried out through 2-D examples which demonstrate the technique
Embodied carbon and construction cost differences between Hong Kong and Melbourne buildings
Limiting the amount of embodied carbon in buildings can help minimize the damaging impacts of global warming through lower upstream emission of CO2. This study empirically investigates the embodied carbon footprint of new-build and refurbished buildings in both Hong Kong and Melbourne to determine the embodied carbon profile and its relationship to both embodied energy and construction cost. The Hong Kong findings suggest that mean embodied carbon for refurbished buildings is 33-39% lower than new-build projects, and the cost for refurbished buildings is 22-50% lower than new-build projects (per square metre of floor area). The Melbourne findings, however, suggest that mean embodied carbon for refurbished buildings is 4% lower than new-build projects, and the cost for refurbished buildings is 24% higher than new-build projects (per square metre of floor area). Embodied carbon ranges from 645-1,059 kgCO2e/m2 for new-build and 294-655 kgCO2e/m2 for refurbished projects in Hong Kong, and 1,138-1,705 kgCO2e/m2 for new-build and 900-1,681 kgCO2e/m2 for refurbished projects in Melbourne. The reasons behind these locational discrepancies are explored and critiqued. Overall, a very strong linear relationship between embodied energy and construction cost in both cities was found and can be used to predict the former, given the latter
MICROPROCESSOR BASED NON-LINEAR ADAPTIVE CONTROLLER
The advent of microprocessors has created the possibility of
developing low cost adaptive controllers for small process plants
which in the past badly needed but could not afford such
controllers. To examine the practicality of developing advanced
low cost microprocessor based controller, this thesis describes
the development of a non-linear adaptive controller for a nylon
crimping plant which is a typical example of small process
plants.
In order to test the algorithm on site, an algorithm
development/implement device basing on a novel multi-tasking
concept was developed. This novel microprocessor based device
can perform program development, on-line algorithm test and data
logging at the same time, while, still maintaining its small size
for easy transportation. When the control algorithm was fully
developed and tested, a low cost dedicated controller using an
Intel 8085 processor was designed to house the algorithm and as a
direct replacement of the original analogue controller
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