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Topic Review
E-Bike Sharing System
Recent data on conventional bike and/or electric bike (e-bike) sharing systems reveal that more than 2900 systems are operating in cities worldwide, indicating the increased adoption of this alternative mode of transportation. Addressing the existing gap in the literature regarding the deployment of e-bike sharing systems (e-BSSs) in particular, this paper reviews their spatio-temporal characteristics, and attempts to (a) map the worldwide distribution of e-BSSs, (b) identify temporal trends in terms of annual growth/expansion of e-BSS deployment worldwide and (c) explore the spatial characteristics of the recorded growth, in terms of adoption on a country scale, population coverage and type of system/initial fleet sizes. To that end, it examines the patterns identified from the global to the country level, based on data collected from an online source of BSS information worldwide. A comparative analysis is performed with a focus on Europe, North America and Asia, providing insights on the growth rate of the specific bikesharing market segment. Although the dockless e-BSS has been only within three years of competition with station-based implementations, it shows a rapid integration to the overall technology diffusion trend, while it is more established in Asia and North America in comparison with Europe and launches with larger fleet sizes.
  • 2.1K
  • 27 Oct 2020
Topic Review
High-Speed Train Noise Control Methods
The sound of trains is considered a disturbance to most residents around the railroad and train passengers, and the sound generated by trains can interfere with sleep, life, and work. With increases in train speed, the main noise from high-speed trains has changed from rolling noise to aerodynamic noise, and the noise level and noise frequency range have also changed significantly. The current methods of noise reduction for trains are discussed.
  • 2.1K
  • 09 Aug 2022
Topic Review
Gas/Oil-Relative Permeabilities
Thermal recovery processes for heavy oil exploitation involve three-phase flow at elevated temperatures. The mathematical modeling of such processes necessitates the account of changes in the rock–fluid system’s flow behavior as the temperature rises. To this end, numerous studies on effects of the temperature on relative permeabilities have been reported in the literature. Compared to studies on the temperature effects on oil/water-relative permeabilities, studies (and hence, data) on gas/oil-relative permeabilities are limited. However, the role of temperature on both gas/oil and oil/water-relative permeabilities has been a topic of much discussion, contradiction and debate. The jury is still out, without a consensus, with several contradictory hypotheses, even for the limited number of studies on gas/oil-relative permeabilities. This study presents a critical analysis of studies on gas/oil-relative permeabilities as reported in the literature, and puts forward an undeniable argument that the temperature does indeed impact gas/oil-relative permeabilities and the other fluid–fluid properties contributing to flow in the reservoir, particularly in a thermal recovery process. It further concludes that such thermal effects on relative permeabilities must be accounted for, properly and adequately, in reservoir simulation studies using numerical models. The paper presents a review of most cited studies since the 1940s and identifies the possible primary causes that contribute to contradictory results among them, such as differences in experimental methodologies, experimental difficulties in flow data acquisition, impact of flow instabilities during flooding, and the differences in the specific impact of temperature on different rock–fluid systems. We first examined the experimental techniques used in measurements of oil/gas-relative permeabilities and identified the challenges involved in obtaining reliable results. Then, the effect of temperature on other rock–fluid properties that may affect the relative permeability was examined. Finally, we assessed the effect of temperature on parameters that characterized the two-phase oil/gas-relative permeability data, including the irreducible water saturation, residual oil saturation and critical gas saturation. Through this critical review of the existing literature on the effect of temperature on gas/oil-relative permeabilities, we conclude that it is an important area that suffers profoundly from a lack of a comprehensive understanding of the degree and extent of how the temperature affects relative permeabilities in thermal recovery processes, and therefore, it is an area that needs further focused research to address various contradictory hypotheses and to describe the flow in the reservoir more reliably.
  • 2.1K
  • 14 Jul 2020
Topic Review
Classic Car
A classic car is an older automobile; the exact definition varies around the world. The common theme is of an older car with enough historical interest to be collectable and worth preserving or restoring rather than scrapping. Cars 20 years and older typically fall into the classic class. Organizations such as the Classic Car Club of America (CCCA) and the Antique Automobile Club of America (AACA) maintain a list of eligible unmodified cars that are called "classic". These are described as "fine" or "distinctive" automobile, either American or foreign built, produced between 1915 to 1998. Post–World War II "classic cars" are not precisely defined and the term is often applied to any older vehicle.
  • 2.1K
  • 02 Nov 2022
Topic Review
Cooper (Profession)
A cooper is a person trained to make wooden casks, barrels, vats, buckets, tubs, troughs and other similar containers from timber staves that were usually heated or steamed to make them pliable. Journeymen coopers also traditionally made wooden implements, such as rakes and wooden-bladed shovels. In addition to wood, other materials, such as iron, were used in the manufacturing process. The trade is the origin of the surname Cooper.
  • 2.1K
  • 17 Oct 2022
Topic Review
Class D Audio Power Amplifier
Class D power amplifiers, one of the most critical devices for application in sound systems, face severe challenges due to the increasing requirement of smartphones, digital television, digital sound, and other terminals. The audio power amplifier has developed from a transistor amplifier to a field-effect tube amplifier, and digital amplifiers have made significant progress in circuit technology, components, and ideological understanding. The stumbling blocks for a successful power amplifier are low power efficiency and a high distortion rate.
  • 2.1K
  • 01 Nov 2022
Topic Review
Sustainable Road Infrastructure
The implementation of sustainability in road infrastructure has become dependent on providing measurements and guidance for including sustainable principles in road projects, resulting in a dozen voluntary certification and rating systems to evaluate the level of sustainability of road design, construction, and maintenance. The predominance of issues which analyse the life cycle assessment of road infrastructures in its both environmental and economic dimension as a way to mitigate their effects on climate change, including the reduction of resources and energy consumption, or of energy consumption and greenhouse gases emissions during the construction and operation stages, respectively.
  • 2.1K
  • 27 Dec 2022
Topic Review
Construction and Demolition Waste Marketplace
Rapid population growth and urbanization have led to an increase in Construction and Demolition (C&D) waste, prompting government and industry bodies to develop better waste management practices. Waste trading has emerged as a targeted intervention to divert waste from landfill sites and create a second life for waste material. This paper examines key barriers and enablers influencing the creation of a marketplace for waste trading. A systematic literature review was undertaken to examine global efforts in creating a marketplace for C&D waste. A framework on enablers and barriers for developing a marketplace for C&D waste emerged from the review, based on market-based, operational, and governance factors. References demonstrated that markets for materials such as glass and metals have already been established, but there are increasing marketplace opportunities for other recycled materials. Technology-based market applications are emerging as targeted interventions to facilitate online trading, which will provide a more accessible and user-friendly marketplace for sellers and buyers. Further research should test the complex interactions between people and technology associated with online waste trading platforms, as well as help develop the business case for a C&D waste marketplace.
  • 2.1K
  • 10 Dec 2020
Topic Review
Metal Additive Manufacturing
Additive Manufacturing (AM), also called 3D printing, has been expanding into several industrial sectors due to the technology providing opportunities in terms of improved functionality, productivity, and competitiveness.
  • 2.1K
  • 10 Mar 2021
Topic Review
Relation between Energy Efficiency and Industry 4.0
The industrial sector is the most energy-consuming sector before the transport and residential sectors. It accounts for about 31% of the overall energy consumption. For this reason, manufacturers are placing increasing emphasis on energy efficiency through improvements in energy management, energy devices, and insulation. Energy efficiency improvement is the application of engineering principles and best practices to control the energy consumption of a facility. It is a continuous process that requires the full involvement of all stakeholders (managers, engineers, workers, etc.) to identify, formulate proposals, and implement energy efficiency technologies and practices to reduce energy consumption. Many technologies and practices are currently available and in development that could save energy if adopted by industry, classified into two main categories: energy management technologies and energy devices. In addition, various tools and methods are used, such as energy monitoring tools, process modeling and integration, optimization and simulation tools, energy analysis and decision support tools, etc. One of the recent innovations is the introduction of Industry 4.0 in manufacturing, in other words, the transition to the new industrial era.
  • 2.1K
  • 15 Jun 2022
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