Use Of Perforator Research Articles

Optimization of hydrothermal performance in industrial heat sinks with innovative perforated pin fin designs: A numerical approach.

This study emphasizes the importance of optimizing pin-finned heat sinks as a means of addressing thermal engineering issues. It aims to investigate the use of perforations and unique fin designs in relation to staggered pin arrays in order to fill a gap in existing research. Three-dimensional incompressible flow simulation is performed with the Fluent software. Modeling turbulence is accomplished by employing the realizable κ-ε models, while the numerical solution of all equations pertaining to fluid flow is carried out with the proper boundary conditions. In order to make a comparison of geometry, the hydrothermal performance factor (HTPF) is utilized for Reynolds number (Re) values ranging from 8500 to 44,502. Using a Re of 44502, the Nusselt number (Nu) was found to be raised by 66.2% for spherical cube pin fins with hexagonal perforation and 70.2% for elliptical perforation, respectively. A reduction of about 17.6% in the pressure drop was seen when compared with an elliptical perforated infinity loop design, which resulted in a higher hydrothermal performance factor (HTPF) that was 70% higher than that of the cylindrical case. Furthermore, the copper-diamond composite, which was placed on an infinity loop-shaped pin fin and had elliptical perforations, yielded a 144% increase in HTPF when the Re is 44502. Taking into account this fact, it can be concluded that the designs that have been offered are ideal for a wide variety of industrial applications that aim to significantly enhance thermal potential.

A model integrating fruit physiology, perforation, and scavenger for prediction of ethylene accumulation in fruit package

The modelling of headspace atmosphere (O2, CO2), relative humidity, condensation, and shelf life of packaged fresh produce has been extensively reported. However, there has been a lack of effort in modelling ethylene (C2H4) accumulation within the packaging or storage environment. This study aimed to address this significant research gap by developing a model for the prediction of C2H4 accumulation within fruit package. This model integrated fruit physiology, gas transmission through perforation, and C2H4 removal by a scavenger made up of KMnO4. The experimental validation was conducted using packaged avocados, encompassing various storage conditions, package (perforation), scavenger, and fruit parameters. The use of perforation effectively maintained C2H4 accumulation below 2 µL L−1 in the avocado package for 12 days within the temperature range of 5 to 25ºC. Moreover, the scavenger successfully kept C2H4 accumulation below 1 µL L−1 within just 8 h for all experimental conditions. The scavenger demonstrated a higher efficacy in C2H4 removal compared to perforation, achieving a complete removal. The level of accuracy through statistical parameters underscores the acceptability and reliability of the model in predicting C2H4 accumulation in fruit package. The model was used to optimize the perforation size according to the required equilibrium O2 and C2H4 accumulation in the avocado package.

Thermal Analysis of New Solar Air Heater with Inclined Perforated Absorber Plates: Experimental Study

Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. Two scenarios are considered to assess the dynamics and efficiency of this perforated SAH, including mair = 0.012 kg/s and 0.024 kg/s. Numerous sensors monitored the dynamics of the perforated SAH and ambient factors for 12 hours in October 2022. The experimental outcomes illustrate that the perforation method remarkably enhances the thermal efficiency of the perforated SAH compared with standard smooth SAHs. The daily thermal efficiency of the perforated SAH reaches 73.30% and 82.65%, while the outlet air temperature experiences peak values of 39 oC and 42 oC at noon and keeps within 90% of its maximum value for 2 hours for the scenarios considered. Improving the convection mechanism causes the flowing air to extract the absorber’s thermal energy more effectively. Hence the SAH can produce an airstream near its maximum temperature for an extended duration. In conclusion, the perforation method is a robust, simple method to boost the thermal efficiency of SAHs.

Numerical Modeling of the Walls Perforation Influence on the Accuracy of Wind Tunnel Experiments Using Two-Dimensional Computational Fluid Dynamics Model

The presented work is dedicated to the development of the mathematical model of a closed-type wind tunnel (WT) in a two-dimensional (2D) formulation based on the computational fluid dynamics (CFD) Unsteady Reynolds Averaged Navier Strokes Equations (URANS) method. The influence of the WT walls perforation percentage on the aerodynamic characteristics of the SC1095 (SC is an abbreviation for “supercritical”) airfoil in a wide range of pitch angles from 0 to 28 degrees has been studied. The obtained data are compared with the aerodynamic characteristics of the airfoil in free flow conditions. It is shown that the use of perforation makes it possible to significantly reduce the influence of the wind tunnel walls on the obtained aerodynamic characteristics of the airfoil bringing them closer to the airfoil characteristics under free flow conditions. The developed low resource-intensive 2D CFD WT model can be used to determine the optimal ratio between the walls perforation percentage, the WT test section dimensions, and the experimental model dimensions for various test modes. Support of WT experiments with the help of preliminary parametric studies based on the 2D CFD model could significantly reduce material costs and increase the accuracy of the obtained results.

Performance evaluation of solar parabolic trough receiver using multiple twisted tapes with circular perforation and delta winglet

A parabolic trough collector (PTC) is one of the concentrating types of a solar collector working in the medium range of temperature from 100–400 °C, for this reason, the efficiency of the solar parabolic trough is less than other types of concentrating solar collector (Point focusing types) in terms of solar to thermal energy conversion, the improvement in efficiency is achieved by various passive heat augmentation techniques in the receiver tube. One of the promising passive techniques is twisted tape inserts used in the receiver due to its simplicity in design and the various possibility of geometric modification. This paper deals with the performance evaluation of the solar parabolic trough receiver system by using passive techniques in the receiver. The testing of the receiver of PTC was done by using multiple perforated twisted tapes with winglets having different perforation ratios ([Formula: see text]) of 0.05, 0.15, 0.25, twist ratios ([Formula: see text]) of 3, 4, 5 and wing depth ratios ([Formula: see text]) of 0.1, 0.2 and 0.3. The number of twisted tapes was fixed at 4. The examination was conducted for Reynolds numbers ([Formula: see text]) varying from 3000–21,000 using air as working fluid. The outcome shows that the use of perforation and winglet in twisted tapes augment the Nusselt number as compared to that of smooth twisted tapes. The maximum thermohydraulic performance ([Formula: see text]) of 2.40 is received by using multiple twisted tapes with perforation and winglet having [Formula: see text] = 0.3, [Formula: see text] = 3, and [Formula: see text] = 0.05 at the Re = 21,000. The correlations for Nusselt number ([Formula: see text]) and friction factor ([Formula: see text]) are also developed with ± 8.5% and ± 8.3% accuracy, respectively.

Use of Perforation and Mathematical Modeling to Increase Solar-Based Steam Distillation System Efficiency

Abstract Solar distillation system has recently been explored and used for the extraction of essential oil from different agricultural herbs. The efficiency of conventional distillation systems is low, and most are driven by hot gases. On the other hand, the solar-driven distillation system has higher efficiency and is based on renewable energy. The modified solar distillation system comprises a Scheffler reflector “concentrator,” newly design steam receiver, distillation still, steam condenser, florentine flask, and biomass-based boiler. A perforated circular pan added at the still bottom and pattern of steam flow and temperature distribution was examined using the computational fluid dynamics (CFD) technique. The CFD simulation results showed that homogeneity in the steam distribution in the distillation still is required to get maximum essential oil extraction efficiency. The energy dissemination at different parts of the newly design solar distillation system was estimated using mathematical modeling. The results of different experiments showed that the yield of essential oils from fresh Rosemary and Cumin was 0.17% w/w and 1.11% w/w, respectively. The efficiency of the modified solar distillation system with a perforated pan and steam receiver was found to be 8% higher than the previous system.

Advantages and disadvantages of using the internal thoracic artery perforators as recipient vessels in autologous breast reconstruction—a narrative review

: The rates of breast reconstruction after mastectomy are rising each year. Autologous breast reconstruction using free tissue transfer is considered the gold standard reconstruction, especially with recent controversy surrounding breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). During free tissue transfer, the flap vessels must be anastomosed to recipient vessels on the chest wall. There are multiple options of recipient vessels during microvascular breast reconstruction. Most commonly, the thoracodorsal vessels or the internal thoracic vessels [also known as the internal mammary (IM) vessels] are used as the recipient vessels for microvascular anastomosis of the free tissue transfer. Other second-line options include the thoracoacromial axis and the lateral thoracic vessels. The use of perforators of the internal thoracic vessels for free flap anastomosis during autologous breast reconstruction has been in use for almost twenty years. They are generally favoured over use of thoracodorsal vessels as they result in medialisation of the flap. In recent years, the use of perforators of the internal thoracic vessels has become popular. Great debate surrounds whether or not they should be used as recipient vessels as opposed to the conventional main vessels. In this article, we discuss the advantages and disadvantages of both techniques to guide the choice of reconstructive microsurgeons.

EVOLUTION OF THE FUNCTIONAL COMPONENT OF ARTISTIC PERFORATION IN THE ARCHITECTURE OF PUBLIC BUILDINGS

The evolution of the use of perforation is considered from the point of view of the functional component in the architecture of public buildings: technological, functional, artistic and decorative, emergent. An att empt is made to identify the stages of the evolution of perforation in the formation of the architectural image of a public building. The objects of architecture are analyzed, differentiated by stylistic characteristics and peculiarities of using the perforation technique as the most important component of the formation of the object’s architecture. The dynamics of the change in the dominant functions of artistic perforation in the context of the evolution of architectural styles is analyzed. The research was carried out with the fi nancial support of the Russian Foundation for Basic Research within the framework of the scientifi c project No. 20-312-90005

Effect of Perforation on the Thermal and Electrical Breakdown of Self‐Rolled‐Up Nanomembrane Structures

AbstractStrain‐induced self‐rolled‐up membranes (S‐RuM) are structures formed spontaneously by releasing a strained layer or layer stacks from its mechanical support, with unique applications in passive photonics, electronics, and bioengineering. Depending on the thermal properties of the strained layers, these structures can experience various thermally induced deformations. These deformations can be avoided and augmented with the addition of strategically placed perforations in the membrane. This study reports on the use of perforations to modify the thermal effects on strained silicon nitride S‐RuM structures. A programmable fuse with well‐defined thermal threshold, ultrasmall footprint, and 2–3 V voltage rating is demonstrated, which can potentially serve as an on‐chip sensing device for power electronic circuits.

Analysis of the Deformation Behavior and Mechanical Properties of Slit‐Perforated Auxetic Metamaterials

Perforated systems constitute one of the most important classes of mechanical metamaterials. In this work, two types of “I”‐shaped slit perforation patterns are proposed which may be used to design perforated systems that mimic the deformation mechanisms of a variety of re‐entrant and anti‐tetrachiral honeycomb systems. Using finite element analysis, it is shown how these systems have the potential to exhibit a large spectrum of negative Poisson's ratios, ranging from extremely negative to zero, which are retained over a wide tensile strain range. A detailed analysis of the deformation behavior of these systems is also presented along with a comparison of the changes in overall expansion and Poisson's ratios of both systems observed upon loading with those predicted by previously formulated theoretical models of re‐entrant and anti‐tetrachiral systems. It is hoped that this work will be of considerable aid in the efforts of scientists to understand the underlying principles governing the production of auxetic mechanical metamaterials through the use of perforations and also stimulate further research on how these and similar mechanisms may be implemented in perforated systems to design other metamaterials with anomalous mechanical properties.

Perforating vessel as an alternative option of a recipient selection for posterior trunk-free flap reconstruction.

The reconstruction of complex defects in the posterior trunk is a challenging problem. Various surgical methods using local flap, propeller flap, and muscle flap have been reported. However, in case where a free flap is inevitable, due to the absence of usable recipient vessels, eventually it may fail to perform or the use of long vessel graft is mandatory. To overcome this problem, we investigated use of perforator as recipient vessel in posterior trunk region and here we report satisfactory outcomes of the cases. Eighteen cases with posterior trunk defects underwent reconstruction surgeries using various free flaps. Perforating vessels, from either the base or margin of the defect, were evaluated by preoperative computed tomography and hand-held Doppler. During the dissection, preoperatively marked perforators, with visual healthy pulsation and appropriate diameter for anastomosis, were selected and used for a recipient vessel for free flap. Perforating vessels from the posterior trunk (0.8-1.3 mm in diameter) were used as recipient vessels and the average size of the defect was 85.2 cm2 . In all cases, one artery and vein was used for anastomosis. No flap necrosis occurred. Hematoma developed in one case and partial wound disruption developed in 2 cases. Surgical method using perforators as recipients for free flap reconstruction can be one of a good treatment option for posterior trunk reconstruction. We think that microsurgeons need not to hesitate when they use perforating vessel as a recipient vessel.

The usefulness of pedicled perforator flap in partial breast reconstruction after breast conserving surgery in Korean women.

BackgroundThe emergence of breast-conserving surgery combined with radiotherapy as the treatment of choice for early stage breast cancer has resulted in greater focus on oncoplastic breast surgery. The use of perforator flaps has particularly gained in reputation for its effectiveness in the reconstruction of partial breast defects in Korean women. Herein, we present our experience with the use of thoracodorsal artery perforator (TDAP) and lateral intercostal artery perforator (LICAP) flaps.MethodsThis study included 33 patients who underwent breast reconstruction using TDAP or LICAP flaps at our hospital from January 2011 to December 2014. Data from patient medical records, and patient satisfaction surveys, which were conducted 12 months postoperatively, were retrospectively evaluated.ResultsTDAP and LICAP flap-based reconstructions were performed in 14 and 19 patients, respectively. Five patients developed complications that required additional intervention. Overall patient satisfaction was observed to be excellent in 15 (46%) patients, and good in 12 (36%).ConclusionsBased on our experience, oncoplastic breast surgery using TDAP or LICAP flap is an effective remodeling technique for small-to-moderate breast defects in Korean women with smaller breasts.

Modified insulated punnets and conventional packaging films for retail storage of robusta banana fruits

The application of poor consumer packaging technology to Banana fruits can increase fruit susceptibility to diseases which affect quality and shelf-life. Understanding the use of appropriate consumer packages is crucial in developing packages for the fresh produce sector. In this study, four different consumer packages and Control Samples (CT) which included Perforated Insulated Punnet (PP), Non-perforated Punnet (NP), Perforated Films (PF) and Non-perforated Films (NF) were used. Fruits in packages were stored at 27°C for 7 days where rate of ripening, weight loss, total soluble solids, taste, pulp texture and consumer acceptance were assessed. The results demonstrated that the use of perforated punnets was better in reducing the rate of ripening. The changes in TSS was progressive in all the treatments but the control sample produced the highest Brix at 16% compared with Brix 15% for fruits in PP, NP. PF and NF. Weight loss was more pronounced in the control sample 11.7% compared with the least weight loss of 0.7% for fruits in NF. Except, Sweetness and TSS without dilution all the parameters assessed were statistically significant at P ≤ 0.05. Based on the results obtained in this research, it can be shown that the use of insulation and perforations of punnets demonstrated appropriateness which offers a promise and can be adopted for consumer use in the fresh produce sector.

Novel technique to avoid twisting of the perforator and main pedicle in the anterolateral thigh flap

i fl c T s t d d t i t he anterolateral thigh (ALT) flap, first described by Song t al. in 1984,1 has become the workhorse perforator flap for econstruction of the head and neck because of its pliability nd versatility. One reason that it may thrombose is that the erforator or the main pedicle (usually the descending branch f the lateral femoral cutaneous artery) is liable to twist or ink, particularly if the flap has a long vascular pedicle.2 Several techniques have been described to avoid the perorator becoming twisted. Celik et al.3 suggested the use of perforators, but it is not always possible to harvest 2 that re feasible simultaneously. For flaps raised with only one erforator, Chen and Tang4 placed a simple suture between tied-off stump of a branch of the main pedicle and the edge f the flap. Cascarini et al.5 modified this and placed a suture rom the fascia or muscle around the pedicle in a loop to the dge of the skin flap. In our experience these techniques can revent the twisting and kinking of a single perforator but hey do not ensure the smooth and simultaneous positionng of the perforator and main pedicle, particularly when the edicle is long. We describe a novel technique to prevent the simultaneous wisting of a single perforator and pedicle. After harvest of the LT flap but before division of the main pedicle, we place a iece of medical gauze under the perforator and the pedicle of he main vessel, and trim the excess part of the gauze along oth vessels. To keep all the vessels in a plane during the peration, we secure the flap and the soft-tissue cuff around he pedicle to the gauze using 3 or 4 sutures (Fig. 1). This can

Perforator Flap versus Conventional Flap.

The introduction of perforator flaps represented a significant advance in microsurgical reconstruction. However, confusion has developed due to the erroneous belief that perforator flaps are different from conventional flaps. The concept of the perforator is not new, but is an idea that evolved from the conventional flap. In fact, some of the flaps used by microsurgeons were perforator flaps. The only difference is the anatomical level of the blood vessels involved; the perforator concept is focused on the distal circulation, so-called 'perforator'. Therefore, thinner sections of tissue can be taken from the conventional donor sites of myocutaneous flaps. With the use of perforators, there are no longer "flap of choice" for specific reconstructions, because conventional donor sites have become universal donor sites, enabling the harvesting of a variety of flaps. Moreover, depending on the surgeon's ability, any flap can be utilized as a perforator-based island flap whose source vessel has been completely preserved. Therefore, tissues can be efficiently customized and tailored into any configuration required for reconstruction. The application of perforator flap technique enables more precise dissection, and allows more selective harvesting of thinner flaps, which will expand options in reconstructive surgery. No doubt the technique will continue to evolve.

Perforator Based Fasciocutaneous Flap Reconstruction of Extremity Skin Cancer

PURPOSE: We have evolved to the use of perforator based fasciocutaneous flaps with closable donor sites as a first choice option in the reconstruction of oncologic defects of the extremities. Here we review our experience and technical nuances. METHODS: A retrospective chart review was completed at New York University Medical Center of the senior author’s extremity skin cancer reconstructions over a 5 year period. Charts were reviewed for patient demographics, co-morbidities, etiology of wound, defect size, wound site, method of reconstruction, complications, need for re-operation, need for adjuvant therapy, follow-up period, and technique-specific factors. RESULTS: A total of 24 charts were reviewed. Patient’s age ranged from 23-104, with a mean of 56. Eight propeller flaps and one posterior interosseous artery flap were performed. Only one patient who had a propeller flap had a complication, small area of wound breakdown, likely attributable to the patient’s history of peripheral vascular disease. Otherwise all propeller flaps achieved a high level of function and cosmesis. All patients treated with adjuvant radiotherapy initiated their courses without delay and went to completion without interruptions or wound complications. Follow-up times ranged between 18 weeks and 18 months. No donor site skin grafts were required, all wounds were decreased in size by 30-50% by subfascial spanning sutures which allowed for tension free flap inset and primarily closable donor sites. CONCLUSIONS: By replacing lost tissue with like nearby vascularized tissue, perforator based fasciocutaneous flaps provide an optimal and durable method of reconstruction of extremity skin cancer wounds.

Free style perforator based propeller flaps: Simple solutions for upper extremity reconstruction!

Background:The introduction of perforator flaps by Koshima et al. was met with much animosity in the plastic surgery fraternity. The safety concerns of these flaps following the intentional twist of the perforators have prevented widespread adoption of this technique. Use of perforator based propeller flaps in the lower extremity is gradually on the rise, but their use in upper extremity reconstruction is infrequently reported, especially in the Indian subcontinent.Materials and Methods:We present a retrospective series of 63 free style perforator flaps used for soft tissue reconstruction of the upper extremity from November 2008 to June 2013. Flaps were performed by a single surgeon for various locations and indications over the upper extremity. Patient demographics, surgical indication, defect features, complications and clinical outcome are evaluated and presented as an uncontrolled case series.Results:63 free style perforator based propeller flaps were used for soft tissue reconstruction of 62 patients for the upper extremity from November 2008 to June 2013. Of the 63 flaps, 31 flaps were performed for trauma, 30 for post burn sequel, and two for post snake bite defects. We encountered flap necrosis in 8 flaps, of which there was complete necrosis in 4 flaps, and partial necrosis in four flaps. Of these 8 flaps, 7 needed a secondary procedure, and one healed secondarily. Although we had a failure rate of 12-13%, most of our failures were in the early part of the series indicative of a learning curve associated with the flap.Conclusion:Free style perforator based propeller flaps are a reliable option for coverage of small to moderate sized defects.Level of Evidence:Therapeutic IV.

Surgical Anatomy of the Medial Sural Artery Perforator Flap

The medial sural (medial gastrocnemius) perforator flap is a thin flap with a long pedicle. It has tremendous potential for applications in a variety of soft-tissue defects. We aimed to further clarify the vascular anatomy of the medial sural region and establish a safe approach for elevation of this flap. Ten fresh cadaveric lower limbs were injected and used in this study. We identified the locations and courses of the medial sural artery perforators and correlated them to anatomic landmarks. The medial sural artery divides into two branches, a medial and lateral branch. Correspondingly, musculocutaneous perforators supplying the overlying skin were oriented in two parallel vertical rows, along the course of the lateral or medial branch of the medial sural artery. Two to six perforators were located 6 cm to 22.5 cm from the popliteal crease. Perforators from the lateral row, nearer the posterior midline, were generally larger. In most cases, a large perforator with a superficial, straight intramuscular course could be identified a mean of 10 cm distal to the popliteal crease and an average of 2 cm from the posterior midline. Based on the above findings, we successfully used this flap in five clinical cases. Perforators of the medial sural artery were arranged in a medial and a lateral row. Use of perforators from the lateral row, nearer the posterior midline, is preferable as these are usually larger in size. A consistent major perforator could always be identified in all specimens. With increased safety and confidence in flap harvesting, the medial sural artery perforator flap may find wider clinical applications. TherapeuticLevel of Evidence: IV.

Experimental investigation of two techniques of arterial microanastomosis used to manage a small-to-large diameter discrepancy

A limiting factor in the use of perforators as recipient vessels is the small-to-large diameter mismatch often encountered. Mismatches less than 1:1.5 may be managed by dilatation of the smaller vessel and by differentially-spaced suture bites. Beyond this ratio, little evidence exists to direct the choice of end-to-end anastomotic technique. Following in silico work and the characterisation of a rodent superficial caudal epigastric/femoral artery model, we conducted an experimental series examining two techniques - an oblique section of the smaller vessel and invaginating the smaller vessel inside the larger. A paired design was used. To test for a difference in patency of >5% required a total of 156 animals (312 anastomoses). Side and technique were randomised. Two investigators performed the anastomoses. A single revision was permitted. Anastomoses were timed and patency was tested at one hour, one week and at six weeks. There was no significant difference in patency at each of the three time points (p = 0.8026, 0.2963 and 0.8137). The invagination technique was significantly faster to perform (p < 0.0001). There was a significant association between the investigator and both patency and the time taken to complete an anastomosis. Independent of the investigator, a revision was more likely to be necessary with the oblique end-to-end technique, and a revision having been performed showed a highly significant association with an anastomosis having failed at 1 h (p < 0.0001, OR 33.333). In the management of microarterial size discrepancy between 1:1.5 and 1:2.5, an invaginating anastomosis is faster to perform and produces comparable patency in a rat model.

Analysis of water vapour transmission rate of perforation-mediated modified atmosphere packaging (PM-MAP)

Perforation-mediated modified atmosphere packaging relies on the use of perforations (tubes) of different dimensions to control O 2 and CO 2 exchange in order to create the desired atmosphere for preservation of fresh fruits and vegetables. No work has been done so far to measure the water vapour transmission rate (WVTR) of this new system. The present study analyses WVTR in different perforation dimensions (diameter: 9, 13 and 17 mm; length: 10, 20 and 30 mm) and storage temperatures (4, 10 and 16 °C). Diameter was the variable with the greatest influence on WVTR, followed by tube length and temperature. The WVTR of perforation-mediated packages increased with increasing temperature and tube diameter while it decreased with increasing tube length. A mathematical model to describe the changes in WVTR as a function of perforation diameter, length, porosity and storage temperature was developed and validated successfully at 7 °C. An experiment with mushrooms showed that the perforation-mediated modified atmosphere packaging could be used for fresh produce provided that the condensation is minimised by using a moisture absorber.