Shrinkage Error Analysis in Selective Laser Sintering Hybrid Milling

Trung Nghiep Nguyen,Hideki Aoyama,Ichiro Araie 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.7

Selective laser sintering hybrid milling (SHM) is an advanced manufacturing process that combines the advantages of both metal powder bed fusion and milling. Using this technology, extremely complex products can be fabricated with high accuracy and reasonable surface quality. SHM has enormous potential in the application of mold fabrication; molds with free-form inner cooling channels can be produced with this technology. The key feature of this technology is that milling is conducted not only after, but also during the forming process. However, this leads to the issue that although machined layers of products have a high level of accuracy without thermal deformation, the addition of new layers causes the materials to undergo shrinkage and deformations to occur on their machined layers. The dimensional error due to shrinkage significantly affects to the accuracy of SHM process; therefore, a completely understanding of the formation error due to shrinkage is highly important in developing efficient solutions. In this study, shrinkage deformation is observed in detail through the results of simulation using finite element analysis. Three shrinkage rules and the unclamping effect are proposed to completely explain the shrinkage error shape in SHM. Finally, an experiment is conducted to confirm the final result of shrinkage.

Improving quality of common reed (Phragmites communis Trin.) silage with additives

Keigo Asano,Takahiro Ishikawa,Ayako Araie,Motohiko Ishida 아세아·태평양축산학회 2018 Animal Bioscience Vol.31 No.11

Objective: Common reed (Phragmites communis Trin.) could potentially provide an alternative resource for silage; however, its silage quality is poor. The aim of this study was to investigate the factors in reed that contribute to poor quality and determine how the use of additives at ensiling could improve fermentation quality. Methods: In Experiment 1, we determined the chemical composition and the presence of indigenous lactic acid bacteria (LAB) in reed. We further examined fermentation quality of reed silage under conditions without additives (NA) and treated glucose (G), lactic acid bacteria (L), and their combination (G+L). In Experiment 2, silage of NA, and with an addition of cellulase and lactic acid bacteria (CL) were prepared from harvested reed. The harvested reeds were fertilized at nitrogen concentrations of 0, 4, 8, and 12 g N/m2 and were harvested thrice within one year. Results: The indigenous LAB and fermentable carbohydrates are at extremely low concentrations in reed. Reed silage, to which we added G+L, provided the highest quality silage among treatments in Experiment 1. In Experiment 2, N fertilization had no negative effect on silage quality of reed. The harvest times decreased fermentable carbohydrate content in reed. The CL treatment provided a higher lactic acid content compared to the NA treatment. However, the quality of CL treated silage at the second and third harvests was significantly lower than at the first harvest, due to a reduction in carbohydrates caused by frequent harvesting. Conclusion: The causes of poor quality in reed silage are its lack of indigenous LAB and fermentable carbohydrates and its high moisture content. In addition, reed managed by frequent harvesting reduces carbohydrate content. Although the silage quality could be improved by adding CL, higher-quality silage could be prepared by adding fermentable carbohydrates, such as glucose (rather than adding cellulases).

Genetics in natural polyploidy in loach

Arai, Katsutoshi 한국어류학회 1995 韓國魚類學會誌 Vol.7 No.2

Loaches widely distribute in the Eurasian Continent and are important for food both in Japan and Korea. Chromosome manipulation including induction of gynogenesis, androgenesis, and polyploidy is powerful tool for potential applications in aquaculture as well as for basic genetic research. The loach Misgrunus anguillicaudatus in Japan has a diploid karyotype(2n=50), but a small number of natural polyploidy have been found. In diploid vertebrates, artificially induced gynogenesis and androgenesis normally give rise to inviable haploid embryos, In contrast, gynogenetic and androgenetic progeny generated by using gametes of the natural tetraploid loach with 100 chromosomes were viable without any treatments for chromosome duplication. The results conclusively demonstrate that the loach with 100 chromosomes is not an evolved-back diploidy, but a true tetraploidy with four sets of homologous chromosomes, The same conclusion was obtained in the tetraploid form of spinous loach Cobitis biwae. Triploid loach produced by hybridizations between normal diploids and natural tetraploids showed male - sterility. While, triploid females laid two sizes of eggs, large and small, and gave viable progeny after backcrossing to normal diploid loach and chromosome manipulation(induced gynogenesis by UV - irradiated spermatozoa and inhibition of the second polar body release by pressure shock). Cytogenetic and flowcytometric analyses on these progeny demonstrate that triploid loach produce 3n large and 1n small eggs. Multilocus - DNA - fingerprintind revealed clonal nature of gynogenetic triploids which were produced by fertilizing the large eggs with UV - irradiated spematozoa. This suggests involvement of unreduced oogenesis in the formation of the large eggs. Cytology and biochemical genetics are now underway to disclose mechanisms responsible for the small egg formation. Pentaploid females produced by inhibiting the polar body release after 4n × 2n hybridizations laid only 2n eggs with medium size. Pentaploid males produced very small number of aneuploid spermatozoa. Hexaploid loach were produced by inhibiting the polar body release after 4n × 4n crosses. Flowcytometry of the testes of hexaploid males showed formation of functuonal 3n spermatozoa. The presence of polyploid in the loach species suggests specially divierged sex determination mechanisms. Deviation of sex from the theoretical ratio was observed when the loach were reared in unusually high temperature.

Effect of the settings of electrospray deposition method on the structure and performance of the fuel cell catalyst layer

Arai Hikaru,Asami Koki,Ito Hajime,Katayama Noboru 한국물리학회 2022 Current Applied Physics Vol.39 No.-

Catalyst layers of proton exchange membrane fuel cells (PEMFC) are formed by electrospray deposition (ESD) method. The cathode catalyst layers are formed and characterized by varying the settings of the system, such as flow rate, applied voltage and the distance between the capillary and the substrate. The dryness of the aggregates during deposition is evaluated using the Damkh¨oler number (Da), and the structure of the catalyst layer is observed using SEM, which shows that the catalyst layer is porous when dry and non-porous when insufficiently dry. In the case of insufficient drying, the structure changed significantly depending on the position. Single cell tests show that the maximum power density varies from 105 to 253 mWcm-2 depending on the settings, even with the same catalyst ink and the same amount of platinum. Electrochemical impedance spectroscopy shows that the charge transfer and mass transport resistances tend to decrease with increase in Da.

근대 오노매토피어의 형태와 의미를 중심으로 한 고찰 -근세부터 현대까지의 변천과정을 중심으로-

( Arai Rie ) 한국일어교육학회 2012 일본어교육연구 Vol.0 No.23

본 논문은 근세부터 현대에 걸- 形態的意味的으로 변화해간 오노매토피어를 근세부터 근대와 근대부터 현대로 나누어서 고찰하였다. 우선 근세부터 근대로의 변천과정은 근세어와 형태가 다른 것을 고찰한 바 「り」가 탈락한 것과, 모음교환과, 合拗音의 直音化가 보였다. 또한 근세어와 의미가 다른 것으로는 「どつさり」「ぎつしり」「むしやくしや」를 중심으로 현대 의미로 변화해 가는 과정을 고찰하였다. 다음으로, 근대에서 보여 지는 擬情語의 특징에 대해서는 근세의 작품가운데에서 발췌한 擬情語의 異なり語數는 13 인 것에 비해 근대문학작품 가운데 오노매토피어를 풍부하게 사용하고 있는 德田秋聲의 4 작품에서 사용되어지는 擬情語의 異なり語數는 23으로 증가하고 있는 것을 알 수가 있었다. 즉, 근세부터 근대의 시대의 흐름에 따라 擬情語의 어휘수도 증가하고 현대어에 비슷해지고 있는 것을 알 수 가 있었다. 또한 근대에서 독자적인 의미범위를 가지고 있었던 「わくわく」에 대해서 긍정적인의미, 부정적인 의미, 중립의 의미, 떨리는 모양의 4가지의 의미범위로 사용되어지는 것을 예문을 통해 고찰하였다. 마지막으로 현대어로의 변천과정에서는 현대어와 형태가 다른 것에 대해서는 근대부터 현대에 걸- 형태가 변화한 오노매토피어를 고찰하고, 또한 의미적 고찰에서는 독자의 의미범위를 지닌 「まじまじ」를 예로 고찰한바, 근세부터 이어지고 있는 「まじまじ」「もじもじ」의 의미와 형태의 혼동이 근대에도 아직 계속되어있는 것을 확인하였다. 本論文は近世から現代にかけて形態的意味的に變化していったオノマトペを、近世から近代と、近代から現代に分けて考察したものである。まず、近世から近代への移り變わりでは近世語と形態が異なるものを考察したところ、「り」の脫落を遂げたもの、母音交換したもの、合拗音の直音化したものが見られた。また近世語と意味が異なるものにおいては「どつさり」「ぎつしり」「むしやくしや」を中心に現代の意味に變化していく過程を考察できた。次に、近代に見られる擬情語の特徵においては、近世の作品の中から拔き出した擬情語の異なり語數は13語なのに對して、近代の文學作品の中でもオノマトペを豊富に使っているとされている德田秋聲の四作品の中で使われている擬情語の異なり語數は23語で增加しているのがわかった。つまり、近世から近代の時代の流れにつれて擬情語の語彙數も增えて、現代語に近づいているのが考察できた。また近代の中で獨自の意味範圍をもっていた「わくわく」についてプラスの意味、マイナスの意味、中立の意味、震える樣子の4つの意味範圍で使われたことを例文を通じて考察した。最後に近代から現代語への移り變わりでは、現代語と形態が異なるものにおいては、近代から現代にかけて形態が變化したオノマトペを考察し、また意味的考察では、獨自の意味範圍をもっていた「まじまじ」を例に考察したところ、近世から續いている「まじまじ」「もじもじ」の意味と形態の混同が近代にもまだ續いていることが確認できた。

Quality assurance and regulation of Kampo medicines

ARAI Ichiro 大韓藥學會 2012 大韓藥學會 總會 및 學術大會 Vol.2012 No.1

New Launching Concept for Free-Fall Lifeboats and Validation by Model Experiments and Numerical Simulations

Arai, Makoto The Society of Naval Architects of Korea 2002 Journal of ship and ocean technology Vol.6 No.1

A new concept for launching free-fall lifeboats, proposed by Yokohama National University is described in this paper. It has been pointed out that, using the conventional single-skid free-fall system, the potential for dangerous lifeboat motions (in which the lifeboat moves backward or jerks on the surface after entering the water) increases with the fall height of the lifeboat. One of the principal causes of this undesirable motion is vertical rotation of the lifeboat during its restricted fall at the edge of the launching skid. Thus a new "double-skid"launching concept is proposed to effectively eliminate the rotation of the lifeboat at the skid end and to enable the lifeboat to move smoothly after entering the water. In order to evaluate the performance of the proposed method, a series of model experiments and numerical simulations is carried out in which two lifeboat models with overall lengths of 1 meter and 6 meters are used. The effects of design parameters such as skid angle and skid height are investigated, and an example of the implementation of this new system at the stern of a large merchant ship is illustrated.

Development of a Small Isotonic Ozone Water Generator

Arai K,Hosoya M,Sasao M,Akashi Y,Hirose H,Yoneyama T,Tamaki T,Miyazaki T,Ando N 대한치과재료학회 2011 대한치과기재학회 학술대회 Vol.2011 No.5

Influence of Z' Boson on Top Quark Spin Correlations at the LHC

Institute of Physics, Jagellonian University 2009 ACTA PHYSICA POLONICA SERIES B Vol.40 No.1

Effects of unparticles on top spin correlation at the Large Hadron Collider

Arai, Masato,Okada, Nobuchika,Smolek, Karel American Physical Society 2009 PHYSICAL REVIEW D - Vol.79 No.7