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91.
H. Md. Azamathulla Chun Kiat Chang Aminuddin Ab. Ghani Junaidah Ariffin Nor Azazi Zakaria Zorkeflee Abu Hasan 《Journal of Hydro》2009,3(1):35-44
A total of 346 sets of bed-load data obtained from the Kinta River, Pari River, Kerayong River and Langat River were analyzed using four common bed-load equations. These assessments, based on the median sediment size (d50), show that the existing equations were unable to predict the measured bed load accurately. All existing equations over-predicted the measured values, and none of the existing bed-load equations gave satisfactory performance when tested on local river data. Therefore, the present study applies a new soft computing technique, i.e. an adaptive neuro-fuzzy inference system (ANFIS), to better predict measured bed-load data. Validation of the developed network (ANFIS) was performed using a new set of bed-load data collected at Kulim River. The results show that the recommended network can more accurately predict the measured bed-load data when compared to an equation based on a regression method. 相似文献
92.
G. Sweis R. Sweis A. Abu Hammad A. Shboul 《International Journal of Project Management》2008,26(6):665-674
The construction industry is a major player in the economy, generating both, employment and wealth. However many projects experience extensive delays and thereby exceed initial time and cost estimates. A host of causes of construction delays in residential projects were identified and classified according to Drewin’s Open Conversion System. The most common causes were evaluated by using both, the data collected in a survey conducted to residential projects consultant engineers, contractors, and owners, and interviews with senior professionals in the field. Most correspondents agreed that, financial difficulties faced by the contractor and too many change orders by the owner are the leading causes of construction delay. Severe weather conditions and changes in government regulations and laws ranked among the least important causes. 相似文献
93.
Colleen Wade Michael Spearpoint Charles Fleischmann Greg Baker Anthony Abu 《Fire Technology》2018,54(4):893-920
There is an increasing desire to use more engineered timber products in buildings, due to the perceived aesthetics of timber and desire for more sustainable architecture. However, there are concerns about fire performance of these products especially in taller buildings. This has led to renewed research to understand the behaviour of timber surfaces in compartments exposed to fire. This paper describes a two-zone calculation model for determining the fire environment within a compartment constructed from timber products where varying amounts of timber are exposed on the walls and ceiling. A set of eight full-scale compartment experiments previously reported in the literature are used to assess the capability of the model. The fire load energy density in the experiments ranged from 92 MJ/m2 to 366 MJ/m2 comprising either wood cribs or bedroom furniture with the largest compartment having dimensions 4.5?×?3.5?×?2.5 m high with an opening 1.069 m wide?×?2.0 m high. The experiments were ventilation-controlled. It is shown that the model can be used to provide conservative predictions of the fire temperatures for compartments with timber exposed on the walls and/or ceiling as part of an engineering analysis. There are several limitations that are discussed including the need to consider the debonding of layers in the case of cross-laminated timber. It is recommended that further benchmarking of the model be done for different ventilation conditions and with engineered timber products where debonding does not occur. This will test the model under a wider range of conditions than examined in this paper. 相似文献
94.
Technology and innovation become more important determinants of corporate competitiveness, and the telecommunications sector is no exception. A good example is found in the development of the mobile phones. Technological development, embodied in innovative functions developed from the first (1G) to third generation (3G) systems, has played significantly important roles in the growth and upheavals of the Japanese mobile phone market. In addition, development in contents, value-added services which are supplied by related firms formed in the vertical structure, charging systems, handset development; all these have made this small gadget an increasingly important part of daily life. 相似文献
95.
The effects of chlorinated polyethylene (CPE) and acrylic impact modifier (AIM) on the thermal degradation of poly(vinyl chloride) (PVC) compounds and composites were investigated. The amounts of AIM and CPE used were fixed at 9 parts per hundred parts of resin (phr), while oil palm empty fruit bunch (OPEFB) fiber content was increased from 0 to 40 phr. To produce composites, the PVC formulations were dry‐blended by using a laboratory blender before being milled into sheets on a two‐roll mill at 165°C. The milled sheets were then hot‐pressed at 180°C. The thermal degradation of the specimens was evaluated by using thermogravimetry in a nitrogen environment. Thermal stability of the PVC/CPE compounds and PVC/CPE/OPEFB composites was improved by the addition of CPE. The CPE retarded the dehydrochlorination of PVC. However, the stabilization effect was reduced by the incorporation of OPEFB at levels of 30 and 40 phr. The presence of AIM accelerated the dehydrochlorination of PVC/AIM compounds and PVC/AIM/OPEFB composites. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers 相似文献
96.
Mohammad Zakaria Mashud Ahmed Mozammel Hoque Abu Shaid 《Journal of Natural Fibers》2020,17(5):676-687
ABSTRACTA relatively better performance of jute fiber and yarn reinforced concrete composites can open up a wide access to application of natural resources in concrete strengthening. In order to achieve this goal, an experimental investigation on the flexural, compressive and tensile strengths of Jute Fiber Reinforced Concrete Composites (JFRCC) and Jute Yarn Reinforced Concrete Composites (JYRCC) has been conducted. To draw a specific conclusion, the mix ratios of 1:1.5:3 and 1:2:4 (by volume) of concrete have been maintained with incorporation of jute fiber and yarn in concrete mortar having different cut lengths with distinct volumetric ratios. Finally, a comparison of the JFRCC and JYRCC strength increments with respect to the plain concrete has been investigated. A significant increment of compressive, flexural and tensile strength was observed only for a short cut length having a low volumetric ratio, where JYRCC increment value was always found progressive. A far more regular arrangement and adequate mixture of JYRCC was also visualized compare to JFRCC in concrete mortar. All the principal increment values were found only in case of JYRCC with a mix ratio of 1:1.5:3. So, it can be concluded that the presence of jute yarn and more cement content can strengthen the concrete to a great extent. 相似文献
97.
98.
Walid M. Ibrahim Najah Abu Ali Hossam S. Hassanein Abd‐Elhamid M. Taha 《Wireless Communications and Mobile Computing》2016,16(18):3316-3331
Deployments over large geographical areas in the Internet of Things (IoT) pose a major challenge for single‐hop localization techniques, giving rise to applications of multi‐hop localizations. And while many proposals have been made on implementations for multi‐hop localization, a close understanding of its characteristics is yet to be established. Such an understanding is necessary, and is inevitable in extending the reliability of location based services in IoT. In this paper, we study the characteristics of multi‐hop localization and propose a new solution to enhance the performance of multi‐hop localization techniques. We first examine popular assumptions made in simulating multi‐hop localization techniques, and offer rectifications facilitating more realistic simulation models. We identify the introduced errors to follow the Gaussian distribution, and the estimated distance follows the Rayleigh distribution. We next use our simulation model to characterize the effect of the number of hops on localization in both dense and sparse deployments. We find that, contrary to common belief, it is better to use long hops in sparse deployments, while short hops are better in dense deployments – despite the traffic overhead. Finally, we propose a new solution that decreases and manages the overhead generated during the localization process. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
99.
Oraib Al-Ketan Marco Pelanconi Alberto Ortona Rashid K. Abu Al-Rub 《Journal of the American Ceramic Society》2019,102(10):6176-6193
The exhibited geometry of catalytic substrates can have a significant influence on the chemical activity and efficiency. Controlling their geometry can be challenging using the traditional techniques. In this work, we propose new and novel catalytic substrates with architected and controllable topologies based on the minimal surfaces framework. A novel design approach and an additive manufacturing (AM) technique were proposed to manufacture the catalytic substrates using ceramic materials. After 3D printing, their mechanical and flow properties were investigated experimentally. An elastic-plastic-damage coupled model was employed to investigate the underlying deformation mechanism of the investigated substrates. Results showed that the CLP substrate exhibited the highest mechanical properties as well as the least pressure drop among the tested substrates. Also, numerical simulations showed that the strut-based substrates exhibit stress localization which leads to faster failure, while stress is distributed more homogeneously in the sheet-based substrates. While the model showed to have a good agreement in the experimental and simulation stress-strain responses, the damage mechanism was not fully captured by the numerical simulations. This was attributed mainly to the process-induced defects in the form of microcracks and microvoids that can alter the nature of deformation and damage. 相似文献
100.
Maher M Al‐Dabbas Mohammed Saleh Mahmoud H Abu‐Ghoush Khalid Al‐Ismail Tareq Osaili 《International Journal of Dairy Technology》2014,67(3):427-436
Microbial levels were significantly (P < 0.05) affected by the temperature‐time treatments used during in‐container heat treatment of the curd, brine concentration and storage duration. A heat treatment of 115 °C × 2 min, in the absence of NaCl, was sufficient to eliminate Mesophilic micro‐organisms, Coliforms, Staphylococcus aureus and Yeast and Moulds for the duration of 1 year of storage. Sensory scores for colour, appearance and texture increased significantly (P < 0.05) with the increase in the NaCl in brine concentration regardless of the temperature‐time treatment. 相似文献