• Title/Summary/Keyword: wrap

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Experimental Study on Performance Characteristics of Air Driven Scroll Expander (공기구동 스크롤 팽창기 성능특성에 관한 실험적 연구)

  • Song, Wonbin;Kwak, Chul Woo;Kim, Tae Kyun;Kim, Ju Young;Kim, Kwang Ho
    • The KSFM Journal of Fluid Machinery
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    • v.19 no.6
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    • pp.50-54
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    • 2016
  • The performance of a scroll expander is the most important factor for the efficiency of small scale Organic Rankine cycle waste heat power generation systems. In this research, a scroll compressor was purchased and operated in reverse to function as a scroll expander. With air as a working fluid, a series of performance test were conducted on this expander by varying the inlet and outlet pressure. Secondly, We have tested through 2000 to 3500 rpm rotational speed to find the maximum power and efficiency of the expander. And last, It was observed in the initial experiments that the design of the expander's orbiting scroll wrap partially blocked the fluid intake which may have caused unnecessary flow resistance. To verify this theory, a small part of the scroll wrap was removed and the performance test was redone. It was observed that the lower back pressure assure the higher efficiency and power of expander and the rotational speed that shows maximum adiabetic efficiency of scroll expander is 69% at 2500 rpm. And by modified wrap of the scroll, we could get volume flow rate for 13% to 19% and power for 5% to 18% increased. But the maximum efficiency of the modified scroll was decreased 8%.

Outcome of complete acellular dermal matrix wrap with polyurethane implant in immediate prepectoral breast reconstruction

  • Naemonitou, Foteini;Mylvaganam, Senthurun;Salem, Fathi;Vidya, Raghavan
    • Archives of Plastic Surgery
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    • v.47 no.6
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    • pp.567-573
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    • 2020
  • Background Polyurethane implants have been used on and off in breast reconstruction since 1991 while prepectoral breast reconstruction has gained popularity in recent times. In this study, we present our outcomes from the use of acellular dermal matrix (ADM) complete wrap with polyurethane implants in prepectoral breast reconstruction. Methods This is a retrospective review of prospectively maintained database from 41 patients receiving complete ADM wrap with prepectoral polyurethane implants over a 3-year period. Selection criteria were adapted from a previous study (4135 Trust Clinical Audit Database) evaluating prepectoral reconstruction with Braxon matrices. Patient demographics, operative data, surgical complications, and outcomes were collected and analyzed. Results A total of 52 implant reconstructions were performed in 41 patients with a mean follow-up of 14.3 months (range, 6-36 months). The overall reported complication rates including early (less than 6 weeks) and late complications. Early complications included two patients (4.9%) with wound dehiscence. One of which had an implant loss that was salvageable. Another patient (2%) developed red-breast syndrome and two women (4.9%) developed with seroma treated conservatively. Late complications included one patient (2%) with grade II capsular contraction, 12 patients with grade I-II rippling and two patients (4.9%) with grade III rippling. Conclusions We present our experience of prepectoral polyurethane implant using complete ADM wrap. This is one of the few papers to report on the outcome of the prepectoral use of polyurethane in immediate implant-based breast reconstruction. Our early observational series show satisfactory outcome and long-term results are warranted by a large multicenter study.

Wrap-around Free Flap in Acute Thumb Injury (족무지 유리피부편을 이용한 급성 수무지 손상의 치료)

  • Lim, H.C.;Suh, S.W.;Hong, J.S.;Jeon, S.J.
    • Archives of Reconstructive Microsurgery
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    • v.3 no.1
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    • pp.81-89
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    • 1994
  • Firstly the wrap-around free flap from the great toe was transferred successfully by Morrison and O'Brien in 1980 for reconstruction in chronic case of amputated thumb distal to the MP joint. Since then, significant bone peg resorption and grafted bone fracture have been reported in most of cases after operation. We have performed thumb reconstructions within 2 weeks after injury in 11 cases which included acute crushing injuries or failed replantation of thumb at Guro Hospital from September, 1983 to October, 1993. The results obtained from this study are as follows: 1. There were 8 males and 3 females and the mean age was 28.8 years old ranged from 3 years old to 50 years old. 2. The most common injury mechanism was machinary injury in 10 of 11 cases. 3. We have performed thumb reconstructions by using wrap-around free flap from the great toe without bone graft in 6 cases and with bone graft in 5 cases within 2 weeks after injury. 4. During 6 years and 1 month mean follow-up period, there were bone resorptions in 3, grafted bone fracture in 1, infections in 2 and soft tissue necrosis in 3 cases. 5. We obtained satisfactable results in respect of function and cosmesis and urged to use this flap for reconstruction in acute thumb injury.

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Surgical Repair of Left Coronary Artery Pseudoaneurysm 10 Years after a Bentall's Procudure (Bentall 수술 10년 후 발생된 좌관상동맥 가성동맥류의 수술 치료)

  • Lee, Sak;Kang, Meyun-Shick;Lim, Sang-Hyun;Chang, Byung-Chul;Hong, You-Sun
    • Journal of Chest Surgery
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    • v.40 no.3 s.272
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    • pp.225-227
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    • 2007
  • The aortic inclusion technique is frequently used in the original Bentall's procedure for the control of excessive postoperative bleeding. Although this procedure has improved the outcome of patients with aortic root disease, there is a high incidence of both early and late complications, including coronary artery stenosis, kinking or pseudoaneurysm formation at the coronary suture lines. Pseudoaneurysm of the ascending aorta is a relatively rare, but fatal complication, which occurs after wrap-inclusion composite graft replacement. Herein, the case of a 45-year-old female, who developed a perigraft aortic pseudoaneurysm 10 years after a Bentall's procedure (wrap-inclusion technique), but was successfully managed using the Cabrol's method, is reported.

Eliminating concrete cover separation of NSM strengthened beams by CFRP end anchorage

  • Hosen, Md. Akter;Jumaat, Mohd Zamin;Islam, A.B.M. Saiful;Kamruzzaman, Mohamed;Huda, Md. Nazmul;Soeb, Mahmudur Rahman
    • Structural Engineering and Mechanics
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    • v.56 no.6
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    • pp.899-916
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    • 2015
  • Upgrading or strengthening of existing reinforced concrete (RC) infrastructure is an emerging demand nowadays. Near Surface Mounted (NSM) technique is very promising approach for flexural strengthening of RC members. However, premature failure such as concrete cover separation failure have been a main concern in utilizing this technique. In this study, U-wrap end anchorage with carbon fiber reinforced polymer (CFRP) fabrics is proposed to eliminate the concrete cover separation failure. Experimental programs were conducted to the consequence of U-wrap end anchorage on the flexurally strengthened RC beams with NSM-steel. A total of eight RC rectangular beam specimens were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM-steel bars and the remaining four specimens were strengthened with NSM-steel bars and U-wrap end anchorage using CFRP fabrics. A 3D non-linear finite element model (FEM) was developed to simulate the flexural response of the tested specimens. It is revealed that NSM-steel (with and without end-anchors) significantly improved the flexural strength; moreover decreased deflection and strains compared with reference specimen. Furthermore, NSM-steel with end anchorage strengthened specimens revealed the greater flexural strength and improve failure modes (premature to flexure) compared with the NSM-steel without end anchorage specimens. The results also ensured that the U-wrap end anchorage completely eliminate the concrete cover separation failure.

Strengthening of concrete damaged by mechanical loading and elevated temperature

  • Ahmad, Hammad;Hameed, Rashid;Riaz, Muhammad Rizwan;Gillani, Asad Ali
    • Advances in concrete construction
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    • v.6 no.6
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    • pp.645-658
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    • 2018
  • Despite being one of the most abundantly used construction materials because of its exceptional properties, concrete is susceptible to deterioration and damage due to various factors particularly corrosion, improper loading, poor workmanship and design discrepancies, and as a result concrete structures require retrofitting and strengthening. In recent times, Fiber Reinforced Polymer (FRP) composites have substituted the conventional techniques of retrofitting and strengthening of damaged concrete. Most of the research studies related to concrete strengthening using FRP have been performed on undamaged test specimens. This contribution presents the results of an experimental study in which concrete specimens were damaged by mechanical loading and elevated temperature in laboratory prior to application of Carbon Fiber Reinforced Polymer (CFRP) sheets for strengthening. The test specimens prepared using concrete of target compressive strength of 28 MPa at 28 days were subjected to compressive and splitting tensile testing up to failure and the intact pieces of the failed specimens were collected for the purpose of repair. In order to induce damage as a result of elevated temperature, the concrete cylinders were subjected to $400^{\circ}C$ and $800^{\circ}C$ temperature for two hours duration. Concrete cylinders damaged under compressive and split tensile loads were re-cast using concrete and rich cement-sand mortar, respectively and then strengthened using CFRP wrap. Concrete cylinders damaged due to elevated temperature were also strengthened using CFRP wrap. Re-cast and strengthened concrete cylinders were tested in compression and splitting tension. The obtained results revealed that re-casting of specimens damaged by mechanical loadings using concrete & mortar, and then strengthened by single layer CFRP wrap exhibited strength even higher than their original values. In case of specimens damaged by elevated temperature, the results indicated that concrete strength is significantly dropped and strengthening using CFRP wrap made it possible to not only recover the lost strength but also resulted in concrete strength greater than the original value.

Effects of Various Temperatures and Packaging Methods on the Storage Properties of Hanwoo Tenderloin (다양한 온도와 포장방법이 한우 안심의 저장성에 미치는 영향)

  • Jong-Hui Kim;Eun-Seon Lee;Mi-Hwa Oh
    • Journal of the Korean Society of Food Culture
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    • v.39 no.2
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    • pp.119-126
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    • 2024
  • This study was conducted to examine the microbiological quality indicators (total bacterial count and coliform count) and physicochemical quality indicators (pH, redness, volatile basic nitrogen [VBN] content) of meat according to various storage temperatures (-20~15℃) and packaging methods (wrap, vacuum). Based on these results, we proposed a safe consumption period. Redness, pH, and VBN content were not considered appropriate for setting the expiration date, as the redness and pH of the meat after spoilage were better than the standard values for both vacuum and wrap packaging (p<0.05). Additionally, the VBN content at 2 and 4℃ increased slightly (fresh level) until the initial time of spoilage (1.0×106 colony-forming unit [CFU]/cm2) and then increased rapidly thereafter. Therefore, the results were not consistent with microbial spoilage. When the decay point was evaluated based on the presence of microorganisms, vacuum packaging extended the storage period approximately 2.5-fold when compared with wrap packaging, and the meat could be stored at 2 or 4℃ for 40 or 23 days, respectively. Therefore, to evaluate meat quality, microbial indicators should be considered first. The microbiological standards proposed in this study can be used for safety management during the distribution of meat. However, to ensure meat safety, additional investigations of appropriate indicators of freshness must be conducted.

An Experimental Study to Prevent Debonding Failure of Full-Scale RC Beam Strengthened with Multi-Layer CFS

  • You Young-Chan;Choi Ki-Sun;Kim Keung-Hwan
    • Journal of the Korea Concrete Institute
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    • v.16 no.6 s.84
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    • pp.867-873
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    • 2004
  • It has been known that debonding failures between CFS(Carbon Fiber Sheet) and concrete in the strengthened RC beams are initiated by the peeling of the sheets in the region of combined large moment and shear forces, being accompanied by the large shear deformation after flexural cracks. These shear deformation effects are seldom occurred in small-scale model tests, but debondings due to the large shear deformation effects are often observed in a full-scale model tests. The premature debonding failure of CFS, therefore, must be avoided to confirm the design strength of full-scale RC beam in strengthening designs. The reinforcing details, so- called 'U-Shape fiber wrap at mid-span' which wrapped the RC flexural members around the webs and tension face at critical section with CFS additionally, were proposed in this study to prevent the debonding of CFS. Other reinforcing detail, so called 'U-Shape fiber wrap at beam end' were included in this tests and comparisons were made between them.