Characterization of atmospheric electrodeless microwave plasma in nitrogen

Journal of Mechanical Science and Technology - In this study, we investigate atmospheric microwave plasmas produced without electrodes while having a larger plasma volume in pure nitrogen. Optical...     

Numerical study on flow and heat transfer characteristics of air-jet cooling system

Journal of Mechanical Science and Technology - The present study aims to numerically analyze the cooling characteristics of the air-jet array in designing more efficient air-cooling system. Heat...     

Simultaneous control of size and surface functionality of silica particle via growing method

Although silane treatment has been studied as a simple and powerful tool to modify the surface of silica particle, there are still several difficulties in terms of controlling surface functionality and size of nanoparticles. Here we develop a growing method to overcome above drawback. The method was processed by continuously injecting precursor using syringe pump. According to the continuous injection, the concentration of precursors in media are properly controlled, and then the continuous injection of precursor promotes the growth of silica particles. When the functional silanes (silane coupling agents) are used, the method can control the amount of surficial functional groups on the silica particle, and can adjust diameter of the particle simultaneously. Furthermore, well-controlled functional silica particles made by growing method are used for catalytic reaction, Knoevenagel reaction, as a solid state catalyst.     

Comprehensive Knowledge Archive Network harvester improvement for efficient open-data collection and management

With the recent increase in data disclosure, the Comprehensive Knowledge Archive Network (CKAN), which is an open-source data distribution platform, is drawing much attention. CKAN is used together with additional extensions, such as Datastore and Datapusher for data management and Harvest and DCAT for data collection. This study derives the problems of CKAN itself and Harvest Extension. First, CKAN causes two problems of data inconsistency and storage space waste for data deletion. Second, Harvest Extension causes three additional problems, namely source deletion that deletes only sources without deleting data themselves, job stop that cannot delete job during data collection, and service interruption that cannot provide service, even if data exist. Based on these observations, we propose herein an improved CKAN that provides a new deletion function solving data inconsistency and storage space waste problems. In addition, we present an improved Harvest Extension solving three problems of the legacy Harvest Extension. We verify the correctness and the usefulness of the improved CKAN and Harvest Extension functions through actual implementation and extensive experiments.     

A multiplexer-based digital passive linear counter (PLINCO)

A ones adder is an important circuit block that is required in many varying applications. This work proposes a design that largely relies on passive transmission-gate multiplexers. Many variations are suggested that can inherently generate a thermometer coded output or one-hot encoded output. The proposed structure has area and power that increases with order n ² for a n number of inputs. A folding technique is then suggested that reduces the area/power to order n log(n). The folded passive linear counter also has a cell-based structure that aids in layout and makes it possible to be added to a digital standard cell library.     

Uncertainty evaluation procedure and intercomparison of bell provers as a calibration system for gas flow meters

Many NMIs (national measurement institutes) and calibration laboratories worldwide use a bell prover as a calibration system for gas flow meters. The basic definition and procedure to estimate the bell prover uncertainty have been given in previous studies. After the announcement of a mutual recognition agreement (MRA) in 1998 by the BIPM (Bureau International des Poids at Mesures), many NMIs have needed to have more details of uncertainty evaluation procedure of the bell prover. In this study, more details of the test procedure of bell prover uncertainty are presented with a modification of position of the temperature and the pressure sensor to measure more exact values. The other modification is to use three precise guide rods with bearings to make the pressure in the bell more stable. Furthermore, a laser interferometer is used to enhance the measurement accuracy of the testing time and the traveling length of the bell. The uncertainty of the bells estimated by the procedure given in this study is 0.13% at the confidence level of 95%, rather than 0.17% of the previous one. Recently, the results of CCM.FF-K6, which is an international comparison of NMIs organized by the CIPM (Comité International des Poids et Mesures), show that the uncertainty of the KRISS (Korea Research Institute of Standards and Science) bell prover estimated by this study is reasonable.     

High performance encapsulation structures utilizing Russian Doll architectures

A Russian Doll encapsulation architecture utilizing pairs of free-standing barrier films and epoxy seals separated by nitrogen spacers is presented, enabling the use of low-cost epoxy to attach two or more free-standing barrier films to a substrate with improved barrier performance. The performance of various Russian Doll encapsulations was evaluated with the calcium thin film optical transmission test, showing improved performance of the Russian doll configuration relative to a non-nested barrier/spacer architecture, and demonstrating that water vapor transmission rates (WVTR) of 0.00021 g/(m², day) or below can be achieved with low-cost materials in this architecture. This WVTR correlates to a predicted lifetime of more than 10 years for bulk heterojunction solar cell modules fabricated and tested by Konarka Technologies (Lowell, MA, USA).     

Four-joint motion data based posture classification for immersive postural correction system

In the modern age, it is important for people to maintain a good sitting posture because they spend long hours sitting. Posture correction treatment requires a great deal of time and expenses with continuous observation by a specialist. Therefore, there is a need for a system with which users can judge and correct their postures on their own. In this paper, we propose a four joint-based motion capture system for building immersive postural correction system. The system collects the subject’s postures, and features are extracted from the collected data to build a database. The data in the DB are classified into normal and abnormal postures after posture learning using the K-means clustering algorithm. An experiment was performed to classify the posture from the joints’ rotation angles and positions; the normal posture judgment reached a success rate of 99.79 %. This result suggests that the features of the four joints can be used to judge and help correct a user’s posture through application to a spinal disease prevention system in the future.     

Static reactive-power compensator using soft-switchingcurrent-source inverter

This paper describes a static reactive-power compensator using a soft-switching scheme. The proposed system is composed of a three-phase current-source inverter with an H-type soft-switching module, which consists of two semiconductor switches, two diodes, and an L-C resonant circuit. The operation of the proposed system was analyzed in detail through a theoretical approach and computer simulation with SPICE. A scaled prototype was built and tested for verifying the feasibility of hardware implementation. The proposed system would be suitable for a high-power application with less switching loss