There is a huge investment in our infrastructure that is vital to our social and economic life. However, the aging and deterioration of the structures require implementing a damage detection system to monitor their st...There is a huge investment in our infrastructure that is vital to our social and economic life. However, the aging and deterioration of the structures require implementing a damage detection system to monitor their structural integrity. In this study, a new alarming system was developed as part of a structural health monitoring system and installed in a scaled-down structure models. The designed system incorporated microprocessors, wireless communication, transducer, and cellular transmission that allow remote monitoring. The developed system facilitates continuous monitoring process of any part of structures and controlled remotely from any location. The system was equipped with data processing subsystem that detects structural behavior irregularity, defects, and potential failures. The system was tested using Linear Variable Differential Transformer (LVDT) for deflections and using strain gages to measure the developed axial and flexural strains in different structural models. Filtering algorithm was used to filter graphs and the data gathered in each loading stage was averaged and plotted to show the abrupt change in the values. The filtering system helps the alarming system to have a clear prediction of possible irregularities. The developed system provides the desired features of low cost, low power, small size, flexibility and easy implementation, remote accessing, early detection of problems, and simplified representation of the results.展开更多
It is well known that small amounts of surfactants, such as 1-Octanol, in the aqueous solution can increase the absorption rate significantly. In this paper, experimental data were obtained for absorption of water vap...It is well known that small amounts of surfactants, such as 1-Octanol, in the aqueous solution can increase the absorption rate significantly. In this paper, experimental data were obtained for absorption of water vapour into an aqueous LiBr solution with different concentrations of 1-Octanol. An experimental rig was specifically designed and developed in this work in order to investigate the effect of surfactant (1-Octanol) on the enhancement of the heat and mass transfer in the absorption process, in addition to, the investigation of the impact of the use of magnetic stirrer inside the absorber. The experimental rig for this study was based on the refrigeration mode of the intermittent vapour absorption system. In order to study the heat and mass transfer in water-lithium bromide vapour absorption air conditioning systems, it was necessary to monitor the concentration of the solution continuously. As a consequence, two procedures for obtaining the LiBr solution concentration were used. The first method was based on the measurement of the density and temperature of the solution, while the second was based on its electrolyte conductivity and the temperature. The experimental results showed that the surfactant concentration has a significant effect on the absorption rate;this is called the Marangoni instability. It has been concluded that, in order to clarify the absorption enhancement phenomenon, it is necessary to understand the physicochemical aspects of the absorption process and the effect of surfactants on the enhancement of such process. Additionally, it has been concluded that new approaches are needed to explain the observed behaviour.展开更多
Monitoring of structures is an important challenge faced by researchers worldwide. This study developed a new structural health monitoring system which utilized the use of microprocessors, wireless communication, tran...Monitoring of structures is an important challenge faced by researchers worldwide. This study developed a new structural health monitoring system which utilized the use of microprocessors, wireless communication, transducer, and cellular transmission that allows remote monitoring. The developed system will facilitate the monitoring process at any time and in any location with less human interference. The system is equipped with data processing subsystem which works on detection of structural behavior irregularity, defects, and potential failures. The system was tested using strain gages to measure the developed strains in different applications and structural models. The results developed using the new system showed that the generated readings from the system followed correctly the expected trend according to structural concepts. The developed system accomplished the desired features of lower cost, less power, reduced size, flexibility and easier implementation, remote accessing, early detection of problems, and simplified representation of the results.展开更多
The purpose of this article offers different algorithms of Weibull Geometric (WG) distribution estimation depending on the progressive Type II censoring samples plan, spatially the joint confidence intervals for the p...The purpose of this article offers different algorithms of Weibull Geometric (WG) distribution estimation depending on the progressive Type II censoring samples plan, spatially the joint confidence intervals for the parameters. The approximate joint confidence intervals for the parameters, the approximate confidence regions and percentile bootstrap intervals of confidence are discussed, and several Markov chain Monte Carlo (MCMC) techniques are also presented. The parts of mean square error (MSEs) and credible intervals lengths, the estimators of Bayes depend on non-informative implement more effective than the maximum likelihood estimates (MLEs) and bootstrap. Comparing the models, the MSEs, average confidence interval lengths of the MLEs, and Bayes estimators for parameters are less significant for censored models.展开更多
The construction industry has been considered an accident prone industry. Alarming statistics indicate thatthe construction industry accounts for 55,000 fatal injuries each year. That is because construction sites are...The construction industry has been considered an accident prone industry. Alarming statistics indicate thatthe construction industry accounts for 55,000 fatal injuries each year. That is because construction sites are often filled with potential hazards that can lead to serious injury or death. Responsibility for these injuries may be attributed to a variety of individuals including owners, contractors or subcontractors, engineers, equipment manufacturers, and architects. This mandated a new safety culture to emerge resulting in a decline in the incidence rate of all recordable nonfatal injury and illness for construction workers. This study explores the safety culture encountered in twolarge construction companies in the USA and Egypt, over the last five years. Comparison of the results recorded in both companies was also conducted. The study also investigated the benefits of focusing on the occupational health in the construction field in Egypt and USA. In addition to the literature review, the research methodology used for this study was inspired by the Contextual Design (CD) Methodology. The study indicated thepositive impact of implementing safety programs on significantly reducing the recordable injuries. It also showed the benefits of focusing on occupational health and wellness, training, and education of workers.展开更多
After corrosion failure of post-tensioned tendons was identified in a Florida bridge in early 2011, laboratory tests were conducted in this study on extracted sections from the failed tendons to identify the grout pro...After corrosion failure of post-tensioned tendons was identified in a Florida bridge in early 2011, laboratory tests were conducted in this study on extracted sections from the failed tendons to identify the grout properties and makeup leading to the failure and also to elucidate the mechanism of corrosion. The initial steps in identification of PT tendons with a high propensity for corrosion initiation or damaged included a detailed visual inspection and identification of voids in the grout. Voids in tendon can be a result of bleed water formation or construction problems. General characteristics of the deficient grout and corrosion behavior of steel in the affected bridge gave a first approach to assessing grout deficiency and corrosion susceptibility. However, refinements in the understanding of the mechanisms causing grout segregation and the elucidation of the role of sulfates, oxygen content, and pore water pH in corrosion development are required.展开更多
文摘There is a huge investment in our infrastructure that is vital to our social and economic life. However, the aging and deterioration of the structures require implementing a damage detection system to monitor their structural integrity. In this study, a new alarming system was developed as part of a structural health monitoring system and installed in a scaled-down structure models. The designed system incorporated microprocessors, wireless communication, transducer, and cellular transmission that allow remote monitoring. The developed system facilitates continuous monitoring process of any part of structures and controlled remotely from any location. The system was equipped with data processing subsystem that detects structural behavior irregularity, defects, and potential failures. The system was tested using Linear Variable Differential Transformer (LVDT) for deflections and using strain gages to measure the developed axial and flexural strains in different structural models. Filtering algorithm was used to filter graphs and the data gathered in each loading stage was averaged and plotted to show the abrupt change in the values. The filtering system helps the alarming system to have a clear prediction of possible irregularities. The developed system provides the desired features of low cost, low power, small size, flexibility and easy implementation, remote accessing, early detection of problems, and simplified representation of the results.
文摘It is well known that small amounts of surfactants, such as 1-Octanol, in the aqueous solution can increase the absorption rate significantly. In this paper, experimental data were obtained for absorption of water vapour into an aqueous LiBr solution with different concentrations of 1-Octanol. An experimental rig was specifically designed and developed in this work in order to investigate the effect of surfactant (1-Octanol) on the enhancement of the heat and mass transfer in the absorption process, in addition to, the investigation of the impact of the use of magnetic stirrer inside the absorber. The experimental rig for this study was based on the refrigeration mode of the intermittent vapour absorption system. In order to study the heat and mass transfer in water-lithium bromide vapour absorption air conditioning systems, it was necessary to monitor the concentration of the solution continuously. As a consequence, two procedures for obtaining the LiBr solution concentration were used. The first method was based on the measurement of the density and temperature of the solution, while the second was based on its electrolyte conductivity and the temperature. The experimental results showed that the surfactant concentration has a significant effect on the absorption rate;this is called the Marangoni instability. It has been concluded that, in order to clarify the absorption enhancement phenomenon, it is necessary to understand the physicochemical aspects of the absorption process and the effect of surfactants on the enhancement of such process. Additionally, it has been concluded that new approaches are needed to explain the observed behaviour.
文摘Monitoring of structures is an important challenge faced by researchers worldwide. This study developed a new structural health monitoring system which utilized the use of microprocessors, wireless communication, transducer, and cellular transmission that allows remote monitoring. The developed system will facilitate the monitoring process at any time and in any location with less human interference. The system is equipped with data processing subsystem which works on detection of structural behavior irregularity, defects, and potential failures. The system was tested using strain gages to measure the developed strains in different applications and structural models. The results developed using the new system showed that the generated readings from the system followed correctly the expected trend according to structural concepts. The developed system accomplished the desired features of lower cost, less power, reduced size, flexibility and easier implementation, remote accessing, early detection of problems, and simplified representation of the results.
文摘The purpose of this article offers different algorithms of Weibull Geometric (WG) distribution estimation depending on the progressive Type II censoring samples plan, spatially the joint confidence intervals for the parameters. The approximate joint confidence intervals for the parameters, the approximate confidence regions and percentile bootstrap intervals of confidence are discussed, and several Markov chain Monte Carlo (MCMC) techniques are also presented. The parts of mean square error (MSEs) and credible intervals lengths, the estimators of Bayes depend on non-informative implement more effective than the maximum likelihood estimates (MLEs) and bootstrap. Comparing the models, the MSEs, average confidence interval lengths of the MLEs, and Bayes estimators for parameters are less significant for censored models.
文摘The construction industry has been considered an accident prone industry. Alarming statistics indicate thatthe construction industry accounts for 55,000 fatal injuries each year. That is because construction sites are often filled with potential hazards that can lead to serious injury or death. Responsibility for these injuries may be attributed to a variety of individuals including owners, contractors or subcontractors, engineers, equipment manufacturers, and architects. This mandated a new safety culture to emerge resulting in a decline in the incidence rate of all recordable nonfatal injury and illness for construction workers. This study explores the safety culture encountered in twolarge construction companies in the USA and Egypt, over the last five years. Comparison of the results recorded in both companies was also conducted. The study also investigated the benefits of focusing on the occupational health in the construction field in Egypt and USA. In addition to the literature review, the research methodology used for this study was inspired by the Contextual Design (CD) Methodology. The study indicated thepositive impact of implementing safety programs on significantly reducing the recordable injuries. It also showed the benefits of focusing on occupational health and wellness, training, and education of workers.
文摘After corrosion failure of post-tensioned tendons was identified in a Florida bridge in early 2011, laboratory tests were conducted in this study on extracted sections from the failed tendons to identify the grout properties and makeup leading to the failure and also to elucidate the mechanism of corrosion. The initial steps in identification of PT tendons with a high propensity for corrosion initiation or damaged included a detailed visual inspection and identification of voids in the grout. Voids in tendon can be a result of bleed water formation or construction problems. General characteristics of the deficient grout and corrosion behavior of steel in the affected bridge gave a first approach to assessing grout deficiency and corrosion susceptibility. However, refinements in the understanding of the mechanisms causing grout segregation and the elucidation of the role of sulfates, oxygen content, and pore water pH in corrosion development are required.
