• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.929-935
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• 2015

The long neck flange is used to connect piping arrangements where the lap joint is applied. Generally, the component can be manufactured by welding, but this method is both time and cost intensive. Embrittlement at the heat affected zones was also considered. A spinning method developed to improve the manufacturing process and solve the problems of welding. The flange area of the long neck flange can be formed by changing the direction of the metal flow, from axial to radial, while maintaining pressure by using an outer mold and a lap roller. A modified process was additionally developed using a round roller rather than the outer mold. In this modification, the round roller can form the shape of all sizes of long neck flange. Using these flexible methodologies, the cost to prepare outer molds and the time to install and remove the molds can be significantly reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.334-339
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• 2020

In this study, the adhesion properties between aluminum and composite materials, composite materials, and composite materials were compared according to the physical surface treatment to improve mechanical bonding at the bonding surface when considering carbon fiber and glass fiber-reinforced composite materials. Bonded specimens were classified into the type of base material and the surface treatment method of the bonding surface. Sandpaper, sandblasting, and plasma were applied as physical surface treatment methods. The bonded specimen was prepared as a single lap joint test specimen. An experiment to measure the lap shear strength was conducted, and the results were compared. The experimental results confirmed that the mechanical abrasion and sandblasting treatment improved the lap shear strength approximately 4 to 5 fold compared to the general specimen without physical surface treatment. In plasma treatment, the experiment was conducted by defining the respective plasma output and treatment time as follows: 150 W and 5 minutes, 150 W and 10 minutes, and 300 W and 3 minutes. Moreover, the lap shear strength results were similar to the previous mechanical surface treatments. On the other hand, the effect on the adhesion properties was small, depending on the plasma treatment conditions.

• Composites Research
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• v.18 no.1
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• pp.1-9
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• 2005

A methodology is presented for the failure prediction of composite single-lap bonded joints considering both of composite adherend failure and bondline failure. An elastic-perfectly plastic model of adhesive and a delamination failure criterion are used in the methodology. The failure predictions have been performed using finite element method and the proposed methodology. The failure prediction results such as failure mode and strength have very good agreements with the test results of joint specimens with various bonding methods and parameters. The influence of variations in the effective strength (that is, adhesion performance) and plastic behavior of adhesive on the failure characteristics of composite bonded Joints are investigated numerically. The numerical results show that optimal joint strength is archived when adhesive and delamination failure occur in the same time.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3223-3227
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• 2015

Objective: We evaluated the association of body mass index (BMI) with perioperative outcomes in patients who underwent laparoscopic or open radical nephroureterectomy. Materials and Methods: This retrospective single-center study included 113 patients who had been diagnosed with upper urinary tract cancer from January 1998 to June 2013 and were treated with laparoscopic nephroureterectomy (Lap group, n=60) or open nephroureterectomy (Open group, n=53). Laparoscopic nephroureterectomy was performed via a retroperitoneal approach following an open partial cystectomy. The two surgical groups were stratified into a normal-BMI group (<25) and a high-BMI group ($BMI{\geq}25$). The high-BMI group included 27 patients: 13 in the Lap group and 14 in the Open group. Results: Estimated blood loss (EBL) in the Lap group was much lower than that in the Open group irrespective of BMI (p<0.01). Operative time was significantly prolonged in normal-BMI patients in the Lap group compared to those in the Open group (p=0.03), but there was no difference in operative time between the Open and Lap groups among the high-BMI patients. Multivariate logistic regression analysis of the data for all the cohorts revealed that the open procedure was a significant risk factor for high EBL (p<0.0001, hazard ratio 8.02). Normal BMI was an independent predictor for low EBL (p=0.01, hazard ratio 0.25). There was no significant risk factor for operative time in multivariate analysis. There were no differences in blood transfusion rates or adverse event rates between the two surgical groups. Conclusions: Laparoscopic radical nephroureterectomy via a retroperitoneal approach can be safely performed with significantly reduced EBL even in obese patients with upper urinary tract cancer.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.172-177
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• 2010

This study presents an explicit dynamic analysis of an adhesively bonded single-lap joint under an impact load. The finite element software, ANSYS LS-DYNA, was used for the analysis and Von Mises stresses were obtained from the analysis. To model the adherents, solid elements were used and a rigid body was assumed for impactor modeling. Three impact heights (1 m, 5 m, and 10 m) were applied to consider different impact conditions and infinite boundary conditions were applied to the end-area of each adherent to save computational time in the analysis. In addition to investigating the stresses in the normal state, we also investigated the stresses in a damaged state (elasticity deterioration), simulated by a change in Young's modulus for 36 of the 3600 elements in the upper layer of the adhesive. The results showed that the location of damage is critical to the stress state of each layer (upper, middle, and lower).

• Elastomers and Composites
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• v.37 no.1
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• pp.49-56
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• 2002

Polypropylene is oxidized with UV/ozone as a function of UV treatment time and ozone flow rate and its surface characteristics are investigated using contart angle measurements and XPS. The aging behavior of oxidized surface is investigated under air, water and ethylene glycol as the aging media. Adhesion strength is also investigated using a lap shear test. Polar surface energy increases with increasing UV/ozone treatment time as well as ozone flow rate. No polar surface energy change is observed under water aging, while under air aging it decreases significantly within 2-3 days and reaches the close value as that of the untreated PP. Adhesion strength increases with increasing UV/ozone treatment time as well as ozone flow rate.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.29-41
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• 2006

This study was to investigate the effect of adding additive as tannin, rice husk and charcoal, for reducing the formaldehyde emission level, on the adhesion properties of urea-formaldehyde (UF) resin for particleboard. We controlled the hot-pressing time, temperature and pressure to determine the bonding strength and formaldehyde emission. Blends of various UF resin/additives (tannin, rice husk and charcoal) compositions were prepared. To determine and compare the effect of additives (tannin, rice husk and charcoal) content, 0, 5, 10 and 15%, by weight of UF resin, were used. $NH_4Cl$ as hardener added. To determine the level of formaldehyde emission, we used the desiccator, perforator and 20 L-small chamber method. The formaldehyde emission level decreased with increased additions of additive (except rice husk). Also, increased hot-pressing time decreased formaldehyde emission level. At a charcoal replacement ratio of only 15%, the formaldehyde emission level is under F ✩ ✩ ✩ ✩ grade (emit < $0.3mg/{\ell}$). Curing of the high tannin additive content in this adhesive system indicated that the bonding strength increased. But, in the case of rice husk and charcoal, the bonding strength was much lower due to the inorganic substance. Furthermore, rice husk was poor in bonding strength as well as formaldehyde emission than tannin and charcoal.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.369-374
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• 1987

Relationships among root yield, planting density (PD), missing plant rate (MR), leaf area index (LAI) , leaf area per plant(LAP), root weight(RW), number of harvested root(RN) and leaf fall plant rate (LFP) were investigated by survey of white ginseng plantations in Pungi and Geumsan area. In Geumsan PD was about twice than in Pungi but yield was low with high rates of MR and LFP. Yield depended on RN in high PD cultivation while on RW in low PD. The effect of MR on yield was prominent in high PD cultivation. PD showed insignificant negative correlation with yield and no clear relation with MR. RN depended on PD and was especially limited by MR, Yield depended on LAI at harvest time and especially at maximum growth time. LAI was not different between high and low PD area but depended only on RN in high PD and only on LAP in low PD area, and limited by MR in both PD. LAP depended highly on RW and this fact seems to be the very reason that LAI could not increase with the increase of PD. All fields showed the suboptimum LAI.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.37-41
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• 2002

Lap splice is used in building construction up to recently. As buildings become higher and larger, the use of high tensile bar is increasing due to increasing in the use of high compression concrete. However the using of high tensile bar in lap splice causes eccentricity and difficulty in placing of concrete inside the form, therefore not allowing enough intervening material. Various mechanical connection are being developed but the coupler of today needs either a secondary intervening material or secondary processing that consumes much time. Therefore a coupler, needing neither a secondary intervening material nor secondary processing, was made in this study which lead to following results. (1) Breaking occurred in all experimented rebar. (2) Acquirement of tension exceeding the standard requirement. (3) Acquirement of elongation percentage within the standard requirement.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.85-95
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• 1996

The purpose of this paper Is to propose a dubbed signal time-synchroniztion technique based on the SOLA(Synchronized Over-Lap and Add) method which has been widely used to modify the time scale of speech signal. In broadcasting audio recording environments, the high degree of background noise requires dubbing process. Since the time difference between the original and the dubbed signal ranges about 200mili seconds, process is required to make the dubbed signal synchronize to the corresponding image. The proposed method finds he starting point of the dubbing signal using the short-time energy of the two signals. Thereafter, LPC cepstrum analysis and DTW(Dynamic Time Warping) process are applied to synchronize phoneme positions of the two signals. After determining the matched point by the minimum mean square error between orignal and dubbed LPC cepstrums, the SOLA method is applied to the dubbed signal, to maintain the consistency of the corresponding phase. Effectiveness of proposed method is verified by comparing the waveforms and the spectrograms of the original and the time synchronized dubbing signal.