78 research outputs found
Study of Alternative GPS Network Meteorological Sensors in Taiwan: Case Studies of the Plum Rains and Typhoon Sinlaku
Plum rains and typhoons are important weather systems in the Taiwan region. They can cause huge economic losses, but they are also considered as important water resources as they strike Taiwan annually and fill the reservoirs around the island. There are many meteorological sensors available for investigating the characteristics of weather and climate systems. Recently, the use of GPS as an alternative meteorological sensor has become popular due to the catastrophic impact of global climate change. GPS provides meteorological parameters mainly from the atmosphere. Precise Point Positioning (PPP) is a proven algorithm that has attracted attention in GPS related studies. This study uses GPS measurements collected at more than fifty reference stations of the e-GPS network in Taiwan. The first data set was collected from June 1st 2008 to June 7th 2008, which corresponds to the middle of the plum rain season in Taiwan. The second data set was collected from September 11th to September 17th 2008 during the landfall of typhoon Sinlaku. The data processing strategy is to process the measurements collected at the reference stations of the e-GPS network using the PPP technique to estimate the zenith tropospheric delay (ZTD) values of the sites; thus, the correlations between the ZTD values and the variation of rainfall during the plum rains and typhoon are analyzed. In addition, several characteristics of the meteorological events are identified using spatial and temporal analyses of the ZTD values estimated with the GPS network PPP technique
Status and Prospects of ZnO-Based Resistive Switching Memory Devices
In the advancement of the semiconductor device technology, ZnO could be a prospective alternative than the other metal oxides for its versatility and huge applications in different aspects. In this review, a thorough overview on ZnO for the application of resistive switching memory (RRAM) devices has been conducted. Various efforts that have been made to investigate and modulate the switching characteristics of ZnO-based switching memory devices are discussed. The use of ZnO layer in different structure, the different types of filament formation, and the different types of switching including complementary switching are reported. By considering the huge interest of transparent devices, this review gives the concrete overview of the present status and prospects of transparent RRAM devices based on ZnO. ZnO-based RRAM can be used for flexible memory devices, which is also covered here. Another challenge in ZnO-based RRAM is that the realization of ultra-thin and low power devices. Nevertheless, ZnO not only offers decent memory properties but also has a unique potential to be used as multifunctional nonvolatile memory devices. The impact of electrode materials, metal doping, stack structures, transparency, and flexibility on resistive switching properties and switching parameters of ZnO-based resistive switching memory devices are briefly compared. This review also covers the different nanostructured-based emerging resistive switching memory devices for low power scalable devices. It may give a valuable insight on developing ZnO-based RRAM and also should encourage researchers to overcome the challenges
Hybrid Ventilation in an Air-Conditioned Office Building with a Multistory Atrium for Thermal Comfort: A Practical Case Study
This study involved a series of computational fluid dynamics simulations to evaluate the effectiveness of stack and displacement ventilation in providing better thermal comfort in an air-conditioned office building. To reduce energy consumption, the public area of the studied building is cooled by air from air-conditioned rooms with lower temperatures. The air, which is driven by buoyancy, then, flows outside through the multistory atrium. The simulation results indicated that displacement ventilation provides superior thermal comfort performance relative to stack ventilation. A design with a higher ceiling, a higher heat source and a lower inlet with cold air can substantially enhance the efficiency of displacement ventilation. Furthermore, handrails near the atrium play a crucial role because they help to retain cold air in the public space for a longer period, thereby contributing to a better predicted mean vote value
Hybrid Ventilation in an Air-Conditioned Office Building with a Multistory Atrium for Thermal Comfort: A Practical Case Study
This study involved a series of computational fluid dynamics simulations to evaluate the effectiveness of stack and displacement ventilation in providing better thermal comfort in an air-conditioned office building. To reduce energy consumption, the public area of the studied building is cooled by air from air-conditioned rooms with lower temperatures. The air, which is driven by buoyancy, then, flows outside through the multistory atrium. The simulation results indicated that displacement ventilation provides superior thermal comfort performance relative to stack ventilation. A design with a higher ceiling, a higher heat source and a lower inlet with cold air can substantially enhance the efficiency of displacement ventilation. Furthermore, handrails near the atrium play a crucial role because they help to retain cold air in the public space for a longer period, thereby contributing to a better predicted mean vote value
Effects of a 6-Minute Fast-Walking Protocol on Changes in Muscle Activity in Individuals with Flatfoot
Flatfoot causes abnormal biomechanics in the lower extremity, resulting in discomfort and excessive burden on lower extremity muscles during functional tasks, and it potentially leads to associated syndromes in the lower extremity. The aim of this study was to investigate how a demanding, repetitive task affects the muscle strength, activities, and fatigue of the lower extremities during function tasks. Nineteen individuals with flexible flatfoot (10M9F, age: 24.74 ± 2.68 years) and fifteen non-flatfoot participants (6M9F, age: 24.47 ± 3.74) took part in this study. All participants performed maximal voluntary isometric contraction and functional tasks, including walking and single-leg standing tests before and immediately after a 6-min fast-walking protocol. A surface electromyography system was used to collect muscle activation data. Our results showed that, after 6 min of fast walking, peroneus longus activity increased only in the non-flatfoot group, and gastrocnemius activity increased in the flexible flatfoot group. In the flexible flatfoot group, greater recruitment in abductor halluces and greater fatigue in the tibialis anterior was observed. Individuals with flexible flatfoot showed altered muscle activation pattern after 6-min fast walking. These findings can provide an evidence-based explanation of associated syndromes in flatfoot populations and lead to potential intervention strategies in the future
Hydrogels for the Application of Articular Cartilage Tissue Engineering: A Review of Hydrogels
The treatment of articular cartilage damage is a major task in the medical science of orthopedics. Hydrogels possess the ability to form multifunctional cartilage grafts since they possess polymeric swellability upon immersion in an aqueous phase. Polymeric hydrogels are capable of physiological swelling and greasing, and they possess the mechanical behavior required for use as articular cartilage substitutes. The chondrogenic phenotype of these materials may be enhanced by embedding living cells. Artificial hydrogels fabricated from biologically derived and synthesized polymeric materials are also used as tissue-engineering scaffolds; with their controlled degradation profiles, the release of stimulatory growth factors can be achieved. In order to make use of these hydrogels, cartilage implants were formulated in the laboratory to demonstrate the bionic mechanical behaviors of physiological cartilage. This paper discusses developments concerning the use of polymeric hydrogels for substituting injured cartilage tissue and assisting tissue growth. These gels are designed with consideration of their polymeric classification, mechanical strength, manner of biodegradation, limitations of the payload, cellular interaction, amount of cells in the 3D hydrogel, sustained release for the model drug, and the different approaches for incorporation into adjacent organs. This article also summarizes the different advantages, disadvantages, and the future prospects of hydrogels
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