Impact of different agitation methods on smear layer cleaning of mesial canals with accentuated curvature

Cordova Abel Teves,Alcalde Murilo Priori,Klymus Michel Espinosa,Bonjardim Leonardo Rigoldi,Vivan Rodrigo Ricci,Duarte Marco Antonio Hungaro 대한치과보존학회 2024 Restorative Dentistry & Endodontics Vol.49 No.2

Objectives This study evaluated the impact of different methods of irrigant agitation on smear layer removal in the apical third of curved mesial canals of 3 dimensionally (D) printed mandibular molars. Materials and Methods Sixty 3D-printed mandibular second molars were used, presenting a 70° curvature and a Vertucci type II configuration in the mesial root. A round cavity was cut 2 mm from the apex using a trephine of 2 mm in diameter, 60 bovine dentin disks were made, and a smear layer was formed. The dentin disks had the adaptation checked in the apical third of the teeth with wax. The dentin disks were evaluated in environmental scanning electron microscope before and after the following irrigant agitation methods: G1(PIK Ultrasonic Tip), G2 (Passive Ultrasonic Irrigation with Irrisonic– PUI), G3 (Easy Clean), G4 (HBW Ultrasonic Tip), G5 (Ultramint X Ultrasonic tip), and G6 (conventional irrigation-CI) (n = 10). All groups were irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Results All dentin disks were 100% covered by the smear layer before treatment, and all groups significantly reduced the percentage of the smear layer after treatment. After the irrigation protocols, the Ultra-X group showed the lowest coverage percentage, statistically differing from the conventional, PIK, and HBW groups (p < 0.05). There was no significant difference among Ultramint X, PUI-Irrisonic, and Easy Clean (p > 0.05). None of the agitation methods could remove the smear layer altogether. Conclusions Ultramint X resulted in the most significant number of completely clean specimens. Objectives This study evaluated the impact of different methods of irrigant agitation on smear layer removal in the apical third of curved mesial canals of 3 dimensionally (D) printed mandibular molars. Materials and Methods Sixty 3D-printed mandibular second molars were used, presenting a 70° curvature and a Vertucci type II configuration in the mesial root. A round cavity was cut 2 mm from the apex using a trephine of 2 mm in diameter, 60 bovine dentin disks were made, and a smear layer was formed. The dentin disks had the adaptation checked in the apical third of the teeth with wax. The dentin disks were evaluated in environmental scanning electron microscope before and after the following irrigant agitation methods: G1(PIK Ultrasonic Tip), G2 (Passive Ultrasonic Irrigation with Irrisonic– PUI), G3 (Easy Clean), G4 (HBW Ultrasonic Tip), G5 (Ultramint X Ultrasonic tip), and G6 (conventional irrigation-CI) (n = 10). All groups were irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Results All dentin disks were 100% covered by the smear layer before treatment, and all groups significantly reduced the percentage of the smear layer after treatment. After the irrigation protocols, the Ultra-X group showed the lowest coverage percentage, statistically differing from the conventional, PIK, and HBW groups (p < 0.05). There was no significant difference among Ultramint X, PUI-Irrisonic, and Easy Clean (p > 0.05). None of the agitation methods could remove the smear layer altogether. Conclusions Ultramint X resulted in the most significant number of completely clean specimens.

A sampling and estimation method for monitoring poultry red mite (Dermanyssus gallinae) infestation on caged-layer poultry farms

Sang-Ik Oh,Ki-Tae Park,Young-Hun Jung,Yoon Jung Do,Chang Yong Choe,Ara Cho,Suhee Kim,Jae-Gyu Yoo 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.3

Background: The poultry red mite, Dermanyssus gallinae, is a serious problem in the laying hen industry worldwide. Currently, the foremost control method for D. gallinae is the implementation of integrated pest management, the effective application of which necessitates a precise monitoring method. Objectives: The aim of the study was to propose an accurate monitoring method with a reliable protocol for caged-layer poultry farms, and to suggest an objective classification for assessing D. gallinae infestation on caged-layer poultry farms according to the number of mites collected using the developed monitoring method. Methods: We compared the numbers of mites collected from corrugated cardboard traps, regarding with length of sampling periods, sampling sites on cage, and sampling positions in farm buildings. The study also compared the mean numbers of mites collected by the developed method with the infestation levels using by the conventional monitoring methods in 37 caged-layer farm buildings. Results: The statistical validation provided the suitable monitoring method that the traps were installed for 2 days on feed boxes at 27 sampling points which included three vertical levels across nine equally divided zones of farms. Using this monitoring method, the D. gallinae infestation level can be assessed objectively on caged-layer poultry farms. Moreover, the method is more sensitive than the conventional method in detecting very small populations of mites. Conclusions: This method can be used to identify the initial stages of D. gallinae infestation in the caged-layer poultry farms, and therefore, will contribute to establishment of effective control strategies for this mite.

개화형상을 모사한 가항력 돛 수납최적화

김희경,정진원,이건희,이동윤,최준우,김병규 항공우주시스템공학회 2017 항공우주시스템공학회지 Vol.11 No.3

In this paper, we propose a new folding method (the blossom method) to increase storage efficiency of drag-sail. To resolve the issue caused by increase in the thickness of the sail, we allowed margin space (offset) along the folding line and made holes at the intersection of offset lines to prevent distortion of film. In addition, to verify applicability of the blossom method, we fabricated quarter of the sail by using Mylar film and conducted a deployment experiment. If the blossom method is applied, storage ratio (storage volume: deployed area) is 1: 68.64, that is approximately 1.88 times more than the z-fold method of folding sailing. 본 논문에서는 drag-sail의 수납 효율을 높이기 위해 새로운 접기 방법인 blossom method를 제안하였다. 가항력 돛을 접을수록 두께가 늘어남에 따라 발생하는 문제점을 해결하기 위해 접히는 라인에 여유공간 (offset)을 주고, offset 라인이 교차하는 지점에는 구멍을 뚫어 film의 일그러짐을 방지하였다. 또한, blossom method의 적용 가능성을 확인하기 위해 mylar film으로 제작하여 전개 실험을 수행하였다. Blossom method를 적용할 경우, 수납부피 대비 전개면적 비인 수납비는 1: 68.64로 기존의 가항력 돛 접기 방법인 z-fold method보다 약 1.88배 향상되었으며, 전개 실험 결과 구멍이나 jamming에 의한 손상이없는 것을 확인하였다.

상관 계수를 이용한 다층퍼셉트론의 계층별 학습

곽영태(Young-Tae Kwak) 한국컴퓨터정보학회 2011 韓國컴퓨터情報學會論文誌 Vol.16 No.8

다층퍼셉트론의 계층별 학습 방법의 하나인 Ergezinger 방법은 출력 노드가 1개로 구성되어 있고, 출력층의 가중치를 최소자승법으로 학습하기 때문에 출력층의 가중치에 조기포화 현상이 발생할 수 있다. 이런 조기 포화현상은 학습 시간과 수렴 속도에 장애가 된다. 따라서, 본 논문은 Ergezinger의 학습 방법을 출력층에서 벡터 형태로 학습할 수 있는 알고리즘으로 확대하고 학습 시간과수렴 속도를 개선하기 위해서 학습 상수를 도입한다. 학습상수는 은닉층 가중치 조정 시, 새로이 계산된 가중치와 기존 가중치의 상관 관계를 계산하여 학습 상수에 반영하는 가변적인 방법이다. 실험은 제안된 방법과 기존 방법의 비교를 위해서 iris 문제와 비선형 근사화 문제를 대상으로 실험하였다. 실험에서, 제안 방법은 기존 Ergezinger 방법보다 학습 시간과 수렴 속도에서 우수한 결과를 얻었으며, 상관 관계를 고려한 CPU time 측정에서도 제안한 방법이 기존 방법보다 약 35%의 시간을 절약할 수 있었다. Ergezinger's method, one of the layer-by-layer algorithms used for multilyer perceptrons, consists of an output node and can make premature saturations in the output's weight because of using linear least squared method in the output layer. These saturations are obstacles to learning time and covergence. Therefore, this paper expands Ergezinger's method to be able to use an output vector instead of an output node and introduces a learning rate to improve learning time and convergence. The learning rate is a variable rate that reflects the correlation coefficient between new weight and previous weight while updating hidden's weight. To compare the proposed method with Ergezinger's method, we tested iris recognition and nonlinear approximation. It was found that the proposed method showed better results than Ergezinger's method in learning convergence. In the CPU time considering correlation coefficient computation, the proposed method saved about 35% time than the previous method.

Analytical calculation method for the axial equivalent elastic modulus of laminated FRP pipes based on three-dimensional stress state

Li Chen,Darong Pan,Qilin Zhao,Li-Cheng-Xi Huang,Liang Chen,Wei Xu 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.1

In engineering design, the axial equivalent elastic modulus of laminated FRP pipe was mostly calculated by the average elastic modulus method or the classical laminated plate theory method, which are based on relatively simplified assumptions, and may be not accurate enough sometimes. A new analytical calculation method for the axial equivalent elastic modulus of laminated FRP pipe was established based on three-dimensional stress state. By comparing the results calculated by this method with those by the above two traditional analytical methods and the finite element method, it is found that this method for the axial equivalent elastic modulus fits well not only for thin-walled pipes with orthotropic layers, but also for thick-walled pipes with arbitrary layers. Besides, the influence of the layer stacking on the axial equivalent elastic modulus was studied with this method. It is found that a proper content of circumferential layer is beneficial for improving the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers, and then can reduce its material quantity under the premise that its axial stiffness remains unchanged. Finally, the meso-mechanical mechanism of this effect was analyzed. The improving effect of circumferential layer on the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers is mainly because that, the circumferential fibers can restrain the rigid body rotations of the oblique fibers, which tend to cause the significant deformations of the pipe wall units and the relatively low axial equivalent elastic modulus of the pipe.

Optimal catalyst layer structure of polymer electrolyte membrane fuel cell

Hwang, D.S.,Park, C.H.,Yi, S.C.,Lee, Y.M. Pergamon Press ; Elsevier Science Ltd 2011 International journal of hydrogen energy Vol.36 No.16

In a membrane electrode assembly (MEA) of polymer electrolyte membrane fuel cells, the structure and morphology of catalyst layers are important to reduce electrochemical resistance and thus obtain high single cell performance. In this study, the catalyst layers fabricated by two catalyst coating methods, spraying method and screen printing method, were characterized by the microscopic images of catalyst layer surface, pore distributions, and electrochemical performances to study the effective MEA fabrication process. For this purpose, a micro-porous layer (MPL) was applied to two different coating methods intending to increase single cell performances by enhancing mass transport. Here, the morphology and structure of catalyst layers were controlled by different catalyst coating methods without varying the ionomer ratio. In particular, MEA fabricated by a screen printing method in a catalyst coated substrate showed uniformly dispersed pores for maximum mass transport. This catalyst layer on micro porous layer resulted in lower ohmic resistance of 0.087 @? cm<SUP>2</SUP> and low mass transport resistance because of enhanced adhesion between catalyst layers and a membrane and improved mass transport of fuel and vapors. Consequently, higher electrochemical performance of current density of 1000 mA cm<SUP>-2</SUP> at 0.6 V and 1600 mAcm<SUP>-2</SUP> under 0.5 V came from these low electrochemical resistances comparing the catalyst layer fabricated by a spraying method on membranes because adhesion between catalyst layers and a membrane was much enhanced by screen printing method.

A consecutive doping method for improvement of electrochemical properties of a commercial activated carbon for organic electric double-layer capacitors

양인찬,유지훈,권다혜,최달수,김명수,정지철 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

In this study, a commercial activated carbon (YP50f) for organic electric double-layer capacitors (EDLC) was improved by a consecutive doping method. The consecutive doping method is a doping method in which nitrogen-doping is used after oxygen-doping. Through this doping method, we successfully prepared a carbon material with high electrical conductivity as well as a large surface area. The surface area of the carbon material was mainly developed during the oxygen-doping process, whereas electrical conductivity was enhanced during the nitrogen-doping process. The consecutively doped carbon exhibited the higher capacitance properties than YP50f when used as an electrode material for organic EDLCs. Consequently, we improved the electrochemical properties of a commercial activated carbon for organic EDLCs by using a consecutive doping method. In addition, we concluded that the consecutive doping method is an effective method for preparing electrode carbon materials for organic EDLCs.

한국 현대시의 종결 방식 연구

윤의섭(Youn Euisoup) 한국언어문학회 2008 한국언어문학 Vol.65 No.-

  This study examines characteristics and the significance of closure method in poetry. A creator presents closure of poetry. A creator considers when a poem should approach to its readers and to form values as an art as well as understands that deciding the final stage of a poem is very important in creating a poem as a complete aesthetic world. Also, closure of a poem presents completeness, stability, unity and artistry. Poetry has a certain sign to prepare for the closure through perception of a creator, that is, closure preparation phase. Primary function of the closure preparation phase is to notify that a poem is about to end. In addition, at the closure preparation phase, previous time flow and meaning of a poem are converged and closure of the poem is prepared. For readers, closure preparation phase is to refine prosodic reading on a poem"s inner rhythm or reading rhythm and to relax and refresh for preparing the closure. This study examines such closure method and its significance by reviewing several representative poems in each era: poems by Kim, So Woel in 1920s; Jeong, Ji Yong in 1930s; and Park, Mok Woel in 1940s. Closure method in Kim, So Woel"s poems sought stability and completeness. Closure method in Jeong, Ji Yong"s poems emphasizes layering and expansion of meanings. Mokwoel Park"s early poems in Cheonglokjib[靑鹿集] show closure method in which meanings and intentions of a poem create and maintain suggestiveness, which is other-oriented closure method. Closure method in modern Korean poetry should be studied further in terms with a reference intentions, significance and world view of a creator. This study hopefully brings the importance of aesthetic significance of closure method in modern Korean poetry to light.

UHF 레이더를 이용한 대류 경계층 고도의 추정

허복행 ( Bok Haeng Heo ),김경익 ( Kyung Eak Kim ) 大韓遠隔探査學會 2001 大韓遠隔探査學會誌 Vol.17 No.1

굴절 지수 구조 매개 변수(refractive index structure parameter) Cn2의 증가는 보통 가온위(virtual potential temperature) θv와 혼합비(mixing ratio) q의 연직 기울기가 최대가 되는 고도에서 발생하며, 대류 경계층(convective toundaly layer)의 고도를 추정하는데 있어서 매우 유용한 매개 변수로 사용된다. 이 연구에서는 대류 경계층 고도의 추정에 이용되는 Cn2 첨두의 발생 특성이 조사되었으며, 또한 UHF 레이더로 관측된 C2n와 연직속도의 분산 σw 자료를 이용하여 대류 경계층 고도를 객관적으로 추정하는 방법이 제시되었다. UHF 레이더의 Cn2 연직 분포에서 첨두는 대류 경계층의 정상부뿐만 아니라 잔류층의 정상부나 구름층에서도 발생하였다. 약한 태양복사로 연직 혼합이 뚜렷하지 않는 경우에 대류 경계층 고도에 상응하는 Cn2 첨두는 레윈존데(rawinsonde) 관측 자료로부터 추정된 대류 경계층 고도보다 약간 낮았다. 반면에, 강한 태양 복사에 의해 연직혼합이 강하고 유입대에서 θv와 q의 연직 기울기가 매우 클 경우에 대류 경계층 고도에 상응하는 Cn2 첨두는 레원존데 관측 자료로부터 추정된 대류 경계층 고도와 잘 일치하였다. Cn2 첨두의 고도를 대류 경계층 고도로 결정하는 최대 후방 산란 강도 방법(maximum backscatter intensity method)은 Cn2 연직 분포에서 하나의 첨두가 있을 경우에는 오류 없이 대류 경계층 고도를 추정하였지만 대류 경계층 고도 위에 잔류층이나 구름층이 있을 경우에는 대류 경계층 고도를 잘못 추정하였다. 본 연구에서 새로이 제시된 방법은 UHF 레이더의 Cn2와 σw자료를 이용하여 대류 경계층 고도로부터 오는 Cn2 첨두를 잔류층이나 구름층으로부터 오는 Cn2 첨두로부터 구별하여 오류 없이 대류 경계층 고도를 추정하였다. 또한 이 방법은 대류 경계층 고도의 일변화 추정에 적용되었으며, 후방 산란 강도의 연적 분포에서 부 개의 첨두가 존재할 경우에도 더욱 선뢰성 있고 안정되게 대류 경계층 고도를 실시간으로 추정하였다. The enhancement of the refractive index structure parameter Cn2 often occurs where vertical gradients of virtual potential temperature θv and mixing ratio q have their maximum values. The Cn2 can be a very useful parameter for estimating the convective boundary layer(CBL) height. The behavior of Cn2 peaks, often used to locate the height of mixed layer, was investigated in the present study. In addition, a new method to determine the CBL height objectively using both Cn2 and vertical air velocity variance σw data of UHF radar was also suggested. The present analysis showed that the Cn2 peaks in the backscatter intensity profiles often occurred not only at the top of the CBL but also at the top of a residual layer or at a cloud layer. The Cn2 peaks corresponding to the CBL heights were slightly lower than the CBL heights derived from rawinsonde sounding data when vertical mixing owing to weak solar heating was not significant and the heights of strong vertical θv gradients were not consistent with that of strong vertical q gradients. However, the Cn2 peaks corresponding to the CBL heights were in good agreement with the rawinsonde-estimated CBL heights when vertical mixing owing to solar heating was significant and the vertical gradient of both θv and q in the entrainment zone was very strong. The maximum backscatter intensity method, which determines the height of Cn2 peak as the CBL height, correctly estimated the CBL height when the Cn2 profile had single peak, but this method erroneously estimated the CBL height when there was a residual layer or a cloud layer over the top of the CBL. The new method distinguished the peak by the CBL height from the peak due to a cloud layer or a residual layer using both Cn2 and σw data, and correctly estimated the CBL height. As for estimation of diurnal variation of the CBL height, the new method provided more stable and reliable estimations of the CBL heights in real time than the maximum backscatter intensity method even if the vertical profile of backscatter intensity had two peaks from the CBL height and a residual layer or a cloud layer.

반죽형 케이크의 믹싱 방법에 따른 품질 특성

진지아 ( Ji Aa Jin ),윤혜현 ( Hye Hyun Yoon ) 한국식품조리과학회(구 한국조리과학회) 2020 한국식품조리과학회지 Vol.36 No.4

Purpose: This study examined the baking quality, quality characteristics, and acceptance of yellow layer cake as a model of batter type cakes according to different mixing methods. Methods: Yellow layer cakes were manufactured using different mixing methods: the single stage method (S), creaming method (C), blending method (B1), and modified blending method (B2). The specific gravity and microscopic observations were used to investigate the condition of batters. The quality characteristics of the yellow layer cake samples were determined by the volume, specific volume, baking quality, texture analysis, staling property, and acceptance. Results: Observations of the batter condition with the specific gravity and microscopic photographs revealed that S to capture the least amount of air while B1 captured the most (p<0.001). The volume of cakes was the highest in C and lowest in S (p<0.01). S also showed the lowest specific volume (p<0.05) and volume index (p<0.001). Although the batter captured the most air, B1 showed a smaller volume than C. B2 showed a high volume similar to C. S showed significantly higher hardness and chewiness than other samples (p<0.001). Springiness was the lowest in S and highest in C (p<0.05). B2 showed the highest acceptance of taste (p<0.05), texture (p<0.05), and overall acceptance (p<0.01). After storage for 5 days, C and B2 showed low staling rates (p<0.001). Conclusion: The cake made by blending method with longer mixing time showed a higher volume, low staling rate, and high acceptance in taste, texture, and overall acceptance.