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61.
The study identifies the causes of inconsistencies between the design and construction of large building projects. To achieve the study objectives, a questionnaire survey was carried out to collect information on potential causes of inconsistencies at the project design and construction interface. Responses from 27 contractors were analyzed. The results suggest that the involvement of designer as consultant, communication gap between constructor and designer, insufficient working drawing details, lack of coordination between parties, lack of human resources in design firm, lack of designer’s knowledge of available materials and equipment, and incomplete plans and specifications were considered as the most important causes of the project design and construction interface inconsistencies. On the other hand, project management as a professional service, weather conditions, nationalities of participants, involvement of the contractor in design conceptual phase, unforeseen problems, involvement of the contractor in design development phase, and government regulations were the least important causes of inconsistencies between professionals at the project design and construction interface in large building projects. 相似文献
62.
The effect of temperature T, electrode separation d and substrate temperature Ts on the I–V characteristics of amorphous films 3500 Å thick, vapour deposited from the alloy TeAsGe (53:36:11 at. %) onto a glass substrate at room temperature, were investigated. The material displayed the behaviour of a negative resistance device with a memory. The behaviour for T=constant is described by the relation V = CIexp (?αI), where C and α are constants for a specimen at constant temperature. The threshold voltage at which the off state transforms to the negative resistance state decreased with T according to the relation Vth = V0exp (Ev/2 kT), where Ev = 0.21 eV. Vth increased with d and decreased with Ts and was related to changes in resistance and structure. Microscope examination showed the formation of filaments containing recrystalized structure arising from Joule heating. 相似文献
63.
A successful and profitable product platform strategy requires both product family architecture and assembly process reasoning.
New product family member production cost and time can be significantly reduced by utilizing available assembly resources,
which can be achieved through systematic assembly process reasoning. A method to utilize existing assembly plant resources,
during the development of new product family members, requires comparing feasible assembly processes with exiting assembly
plants. The set of feasible assembly sequences for a product family member is modelled by developing an assembly sequence
design space, which is combinatorial in nature, and applying constraints on the space. Models that capture effects of constraints
on these spaces, explicitly represent feasible regions, and efficiently enumerate designs within this space are investigated.
The feasible space is then searched to determine new product assembly sequence that will require minimum change in the current
assembly plant. An automotive front structure family is utilized to demonstrate application of the assembly sequence space
to perform assembly reasoning to increase exiting assembly plant resource utilization. 相似文献
64.
Product family design and platform-based product development: a state-of-the-art review 总被引:8,自引:6,他引:8
Jianxin? Jiao Timothy?W.?Simpson Zahed?Siddique 《Journal of Intelligent Manufacturing》2007,18(1):5-29
Product family design and platform-based product development has received much attention over the last decade. This paper
provides a comprehensive review of the state-of-the-art research in this field. A decision framework is introduced to reveal
a holistic view of product family design and platform-based product development, encompassing both front-end and back-end
issues. The review is organized according to various topics in relation to product families, including fundamental issues
and definitions, product portfolio and product family positioning, platform-based product family design, manufacturing and
production, as well as supply chain management. Major challenges and future research directions are also discussed. 相似文献
65.
66.
Khan Muhammad Imran Dong Huang Shabbir Faisal Shoukat Rizwan 《Microsystem Technologies》2018,24(2):869-877
Microsystem Technologies - Electronic devices are shrinking day by day, while the speed and reliability is increasing. At the same time, IC designs and micro/nano electronic systems are becoming... 相似文献
67.
The relationship between electricity consumption,electricity prices and GDP in Pakistan 总被引:1,自引:0,他引:1
This study analyzes the relationship among electricity consumption, its price and real GDP at the aggregate and sectoral level in Pakistan. Using annual data for the period 1960–2008, the study finds the presence of unidirectional causality from real economic activity to electricity consumption. In particular, growth in output in commercial, manufacturing and agricultural sectors tend to increase electricity consumption, while in residential sector, growth in private expenditures is the cause of rising electricity consumption. The study concludes that electricity production and management needs to be better integrated with overall economic planning exercises. This is essential to avoid electricity shortfalls and unplanned load shedding. 相似文献
68.
Ranimol Stephen A. M. Siddique Fouran Singh Lekshmi Kailas Seno Jose Kuruvilla Joseph Sabu Thomas 《应用聚合物科学杂志》2007,105(2):341-351
The effect of microfillers on the thermal stability of natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) latices, and their 70/30 NR/XSBR blend were studied using thermogravimetric method. Microcomposites of XSBR and their blend were found to be thermally more stable than unfilled samples. The activation energy needed for the degradation of polymer chain was calculated from Coats‐Redfern plot. Activation energy needed for the thermal degradation of filled samples was higher than unfilled system. It indicated the improved thermal stability of the filled samples. The ageing resistance of the micro‐filled samples was evaluated from the mechanical properties of aged samples. The thermal ageing was carried out by keeping the samples in hot air oven for 7 days at 70°C. The mechanical properties such as tensile strength, modulus at 300% elongation, and strain at break were computed. As compared to unfilled samples, micron‐sized fillers reinforced systems exhibited higher ageing resistance. Finally, an investigation was made on the influence of ion‐beam irradiation on microcomposites of NR, XSBR latices, and their 70/30 blend systems using 28Si8+ performed at 100 MeV. The surface changes of the samples after irradiation were analyzed using X‐ray photoelectron spectroscopy. The results of XPS measurements revealed that the host elements were redistributed without any change in binding energies of C1s, O1s, and Si2p. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
69.
M. D. Migahed A. El-Khodary M. Hammam A. Shaban H. R. Hafiz 《Journal of Materials Science》1990,25(6):2795-2799
Thermally stimulated depolarization currents of styrene-acrylonitrile and acrylonitrile-butadiene-styrene copolymers have been investigated in the high-temperature range. A peak associated with the glass transition temperature was observed which has the characteristic of a dipolar relaxation process. Parameters such as activation energy and relaxation time associated with the dipolar relaxation process have been calculated. The compensation effect is observed to be valid and the value of the compensation temperature differs slightly from one compound to other. The linear relationship between the activation energy and the logarithm of the preexponential factor of the relaxation time is discussed in terms of the compensation temperature and the chain environment. 相似文献
70.