Geosynthetic-sheet pile reinforced foundation for mitigation of earthquake and tsunami induced damage of breakwater

Earthquake and tsunami impose great threats on the stability of a breakwater. Foundation of the breakwater is weakened by these forces, and it may result in collapse of the breakwater. Lateral flow of seabed soils take place beneath the breakwater, and excess pore water pressure is generated in the foundation by an earthquake that precedes tsunami. These factors may lead to excessive settlement and horizontal displacement of the breakwater. Tsunami introduces additional instability to the deformed breakwater. Due to water level difference between seaside and harborside of the breakwater during a tsunami, seepage occurs through its foundation, and it may cause pipping of seabed soils. Tsunami induced scouring of mound is also a big problem for the stability of the breakwater foundation. Finally, these result in failure of the breakwater foundation. Due to failure of its foundation, the breakwater may collapse and cannot block the tsunami. It results in entering of the tsunami in coastal areas. In order to make a breakwater resilient against earthquake and tsunami induced damage, reinforcing countermeasures were developed for foundation of a breakwater. Geogrid, gabions and sheet piles were used for reinforcing a foundation model. The effectiveness of the model is evaluated through physical modeling for mitigating the earthquake and tsunami induced damage. Shaking table tests were performed to determine the effectiveness of the reinforced model under different earthquake loadings. Tsunami overflow test was conducted on the same deformed model in order to see the effects of tsunami on the model. Comparisons were made between the unreinforced and reinforced foundations, and it was observed during the tests that the reinforced foundation performed well in reducing the damage of the breakwater brought by the earthquake and tsunami. Overall, this study is useful for practice engineering, and the reinforced foundation model can be adopted for designing a breakwater foundation to reduce damage triggered by an earthquake and tsunami in the future.     

基于项目方法的项目型组织战略管理

本文讨论了一个在竞争性管理环境中的项目组织进行战略安排的理论框架.项目组织需要面对不断改进的战略和服务以适应动态的商业环境.理想上,一个基于项目的组织应该具备使用一种整合方法的能力,这种方法可以使项目能力和资源的设计与使用达到最佳状态.就交付服务和开发一种基本的有形产品而言,项目产出物构成了项目能力的主干.确切地说,在概念阶段对项目产出物的设计和计划给项目组织战略意图方面带来的价值增加超过了项目实施阶段.通过在项目早期将战略和商业目标与可行性、执行、需求和各种规范相结合,仿真模型可以对项目过程进行分析,并有助于形成一个合适的项目配置基准.通过考察整个生命周期的方法,本研究展示的框架整合了自始至终的项目信息和基本过程.本文通过一个案例研究来展示仿真模型如何应用于有效地评价备选项目过程,以及如何将特定的标杆项目组织的产出和需求联系起来.     

Influence of Kevlar Hybridization on Dielectric and Conductivity of Bamboo Fiber Reinforced Epoxy Composite

In a motive to develop a natural fiber-based dielectric material, bamboo fiber-reinforced epoxy composite is fabricated using hand layup technique and hybridized with Kevlar K29 fiber to enhance its properties. Dielectric and conductivity studies are performed using LCR meter on the composite samples as a function of frequency (100 Hz-1 MHz) and temperature (22–120°C). From the experiment, it is observed that the dielectric properties of bamboo-based natural composite are significantly enhanced by Kevlar hybridization. And also the influence of variation in frequency and temperature on the electrical properties i.e. dielectric and conductivity of the fabricated composite was studied. The morphological study is also carried out using scanning electron microscope (SEM).     

Linking project health to project performance indicators: Multiple case studies of construction projects in Saudi Arabia

This research presents an empirical study of the relationship between project health and project performance in the project delivery context. Based on an existing Project Health Check (PHC) framework, the relationship has been tested in terms of a set of predefined indicators through the use of case study approach. The Swiss Cheese model was employed as a guiding principle to represent the links between PHC indicators and project Key Performance Indicators (KPIs). Three cases of construction projects in Saudi Arabia were investigated through a comprehensive review of the project performance history, using current performance indicators to establish the first slice of the Swiss Cheese model. PHC assessments were then conducted to shape the second slice of the model, which represent the maturity level of the project management. The relationships between the two slices were obtained from semi-structured interviews with the project managers. These relationships were analysed qualitatively by tracking patterns across the three cases. The result was used to develop the Swiss Cheese Performance Management Framework, which can potentially serve to help project managers identify the root causes of any shortcomings at the early stage in the project delivery process. This in turn can assist project managers in managing the overall project performance more effectively.     

Mobile sink based data collection for energy efficient coordination in wireless sensor network using cooperative game model

Telecommunication Systems - Multi-hop communication in a wireless sensor network leads to unbalanced energy consumption, creating “hot spots” around the sensor nodes. Selection of paths...     

Quadrature space shift keying performance with dual‐hop AF relay over mixed fading

Quadrature space shift keying (QSSK) modulation combined with cooperative relaying improves the reliability in communication and enhances the overall spectral efficiency. Here, QSSK scheme is analyzed for multiple‐input multiple‐output (MIMO) wireless communication system with dual‐hop amplify‐and‐forward (AF) relaying systems over asymmetric mixed Rayleigh/Rician and symmetric Nakagami‐m/Nakagami‐m fading channels. Analytical expressions for cumulative distribution function (CDF) of the end‐to‐end signal‐to‐noise ratio are derived and used to evaluate the average bit error probability (ABEP) of QSSK modulation in mixed asymmetric and symmetric fading channels. The obtained ABEP expression is in the form of Whittaker function, which can be numerically evaluated using its numerical or series representation. Numerical and simulation results are presented to illustrate the impact of fading parameters on the system performance.     

A modular neuro-wavelet based non-unit protection scheme for zone identification and fault location in six-phase transmission line

To overcome the constraints on land availability, infrastructure and environmental problems, six-phase transmission lines have been proposed as a potential alternative to increase the power transfer capability of existing transmission lines without major modification in the existing structure of three-phase double-circuit system. The non-availability of a proper protection scheme due to large number of possible faults has been the prime reason behind the low popularity and acceptance of six-phase system. In this regard, the present work proposes a protection scheme for six-phase transmission line based on the hybridization of discrete wavelet transform and modular artificial neural network. The fault information (approximate coefficients) in the voltage and current signals is captured using discrete wavelet transform. The standard deviation of the coefficients of voltage and current signals in each phase is then computed and given as input to modular artificial neural network, which aims at identifying the faulty section/zone and estimate its location. Test results exhibit that the proposed scheme effectively discriminates the faulted section and estimates the fault location with maximum error of 0.675 %. It offers primary protection to the total line length and also provides remote backup protection for the adjacent reverse section of the line using data at relaying point only and thus avoids the need of a communication link.

     

Recent Advances in Transition Metal-Catalyzed Functionalization of gem-Difluoroalkenes

gem-Difluorinated alkenes are readily accessible building blocks that can undergo functionalization to provide a broad spectrum of fluorinated and non-fluorinated products. Herein, we review recent (since 2017) transition metal-catalyzed transformations of these specialized alkenes and summarize general reactivity patterns of these reactions. Many transition metal-catalyzed reactions undergo net C−F bond functionalization reactions to deliver monofluorinated products. These reactions typically proceed through β-fluoroalkylmetal intermediates that readily eliminate a β-fluoride to deliver monofluoroalkene products. A second series of reactions exploit coinage metal fluorides to add F⁻ to the gem-difluorinated alkene, and further functionalization delivers trifluoromethyl-containing products. In stark contrast, few transition metal-catalyzed reactions proceed in net “fluorine-retentive processes” to deliver difluoromethylene-based products.     

Multifaceted potentials of tire-derived three dimensional geosynthetics in geotechnical applications and their evaluation

Scrapped tire-derived materials, such as tire chips and tire shreds, can be categorized as three dimensional geosynthetics. This paper introduces recent Japanese experience in geotechnical related applications of geosynthetics that focus mainly on tire chips and tire shreds. Three specific applications of tire chips and tire shreds are introduced here. They are: (1) tire shreds to improve drainage; (2) sand-mixed tire chips to mitigate earthquake damage; and (3) tire chips mixed with cement-treated clay to improve toughness and ductility. The developed techniques related to these applications, verification through model testing, as well as element testing and the field applications are presented. It was observed that tire shreds can maintain high permeability even under a high compressive load. When tire chips and/or sand-mixed tire chips are used as a compressible cushion, not only the dynamic load against a structure but also the dynamically induced permanent structural displacement could also be significantly reduced. On the other hand, mixing tire chips with cement-treated clay gives toughness to the geomaterial, and thus provides resistance against the development of cracks during deformation. In addition, an X-ray CT investigation of deformation behavior of such materials demonstrated the success of using cement-treated clay with tire chips as a sealing material to protect leakage of contaminated materials at a waste disposal site in Tokyo bay area.