Common Configuration Research Articles

Wood Polymer Composite Based on Poly-3-hydroxybutyrate-3-hydroxyvalerate (PHBV) and Wood Flour-The Process Optimization of the Products.

This study involved the optimization of the molded pieces manufacturing process from a poly-3-hydroxybutyrate-co-3-hydroxyvalerate biocomposite containing 30% wood flour by mass. The amount of wood flour and preliminary processing parameters were determined on the basis of preliminary tests. The aim of the optimization was to find the configuration of important parameters of the injection process to obtain molded pieces of good quality, in terms of aesthetics, dimensions, and mechanical properties. The products tested for quality were dog bone specimens. The biocomposite was produced using a single-screw extruder, whereas molded pieces were made using an injection molding process. The Taguchi method was applied to optimize the injection molding parameters, which determine the products quality. Control factors were selected at three levels. The L27 orthogonal plan was used. For each set of input parameters from this plan, four processing tests were performed. The sample weight, shrinkage, elongation at break, tensile strength, and Young's modulus were selected to assess the quality of the molded parts. As a result of the research, the processing parameters of the tested biocomposite were determined, enabling the production of good-quality molded pieces. No common parameter configuration was found for different optimization criteria. Further research should focus on finding a different range of technological parameters. At the same time, it was found that the range of processing parameters of the produced biocomposite, especially processing temperature, made it possible to use it in the Wood Polymer Composites segment.

Enhanced X-ray free-electron laser performance with optical klystron and helical undulators.

This article presents a demonstration of the improved performance of an X-ray free-electron laser (FEL) using the optical klystron mechanism and helical undulator configuration, in comparison with the common planar undulator configuration without optical klystron. The demonstration was carried out at Athos, the soft X-ray beamline of SwissFEL. Athos has variable-polarization undulators, and small magnetic chicanes placed between every two undulators to fully exploit the optical klystron. It was found that, for wavelengths of 1.24 nm and 3.10 nm, the required length to achieve FEL saturation is reduced by about 35% when using both the optical klystron and helical undulators, with each effect accounting for about half of the improvement. Moreover, it is shown that a helical undulator configuration provides a 20% to 50% higher pulse energy than planar undulators. This work represents an important step towards more compact and high-power FELs, rendering this key technology more efficient, affordable and accessible to the scientific community.

Design and Analysis of Lifting Carriage of 4T Overhead Stacker Crane

The Overhead Stacker Crane is a hybrid device that combines the features and constructions of "Industrial Forklifts" and "Electric Overhead Cranes." Stacker cranes are equipment with varied levels of automation that are used to store materials. They travel along the aisles of the operating areas, where they enter, position, or extract the material. This type of crane is widely used in assembly shops, production stores, warehouses, etc. Each application needs customizing. The lifting carriage of different overhead stacker crane design is studied in this study. The new design has two advantages: the lifting carriage is bracketed to the mast of the overhead stacker, and the new lifting mechanism is more compact. The most common structure configurations are single-mast and twin-mast constructions. Single-mast structures are used for investigation in our research. A live example has been chosen, and several design engineering stages have been implemented, with the goal of achieving compliance with safety-related standards as well as possible enhancements for future consideration. All the concerned parts have been 3D modelled, analyzed using classical means as well as advanced means of FEA. The goal of using design engineering concepts is to provide a verified design with documentation that can be manufactured with or without indicated improvements. Static analysis of identified parts is performed using both hand calculation and the FEA approach.

A Comprehensive Review of Existing and Pending University Campus Microgrids

Over the past few decades, many universities have turned to using microgrid systems because of their dependability, security, flexibility, and less reliance on the primary grid. Microgrids on campuses face challenges in the instability of power production due to meteorological conditions, as the output of renewable sources such as solar and wind power relies entirely on the weather and determining the optimal size of microgrids. Therefore, this paper comprehensively reviews the university campuses’ microgrids. Some renewable energy sources, such as geothermal (GE), wind turbine (WT), and photovoltaic (PV), are compared in terms of installation costs, availability, weather conditions, efficiency, environmental impact, and maintenance. Furthermore, a description of microgrid systems and their components, including distributed generation (DG), energy storage system (ESS), and microgrid load, is presented. As a result, the most common optimization models for analyzing the performance of campus microgrids are discussed. Hybrid microgrid system configurations are introduced and compared to find the optimal configuration in terms of energy production and flexibility. Therefore, configuration A (Hybrid PV- grid-connected) is the most common configuration compared to the others due to its simplicity and free-charge operation.

Computed tomographic‐planned repair of short incomplete sagittal fractures of the proximal phalanx

SummaryBackgroundShort incomplete sagittal fractures of the proximal phalanx are common in racehorses. Configurations vary; surgical planning has been performed using radiography which has limited ability to differentiate between common configurations. Computed tomographic (CT) imaging accurately maps fracture configuration and may be contributory to case management.Objectives(i) Describe a surgical technique for CT‐planned repair of short incomplete sagittal fractures of the proximal phalanx and (ii) report case outcomes.Study designRetrospective case series (2019–2023).MethodsCT‐planned surgical repair of short incomplete sagittal fractures of the proximal phalanx was performed under radiographic control. Following repair, screw position was assessed with CT. Case records, radiographic and CT images were reviewed. Follow‐up information was obtained from referring veterinarians, race records and owner/trainers.ResultsTen fractures were confined to the dorsal cortex and subchondral bone. One fracture extended the full dorsoplantar depth of the bone. One fracture was confined to the subchondral bone centrally. Screw repair was planned using CT, to cross the fracture, or to position as close as possible while avoiding penetration of the articular surface. Surgery was performed under radiographic control, and subsequent CT examination confirmed screw placement as planned. Fractures healed radiographically in all 10 imaged cases. All horses were sound at follow‐up examination. One horse was retired to stud after surgery. Eleven horses returned to full training and 10 raced.Main limitationsThe case outcomes reported are only relevant to similar populations of Thoroughbred racehorses. The lack of a cohort of control horses limits conclusions that can be drawn relating to the contribution of this surgery to case management.ConclusionsCT planned repair of short incomplete sagittal fractures of the proximal phalanx, with screws positioned according to fracture location, can be reliably performed and is associated with good outcomes.

An open flame and smoke detection dataset for deep learning in remote sensing based fire detection

ABSTRACT The early warning of fires is pivotal for preventing substantial economic losses and ecological damage. However, the enhancement of fire model generalization performance still faces challenges due to limitations in existing fire datasets, such as image quantity and heterogeneity. Taking the advantage of rapid advancements in remote sensing technology and artificial intelligence, we introduce the Flame And Smoke Detection Dataset (FASDD), a pioneering collection comprising over 120,000 heterogeneous images covering various fire scenarios, aiming to promote the evolution of fire detection models. FASDD serves as a challenging benchmark for object detection tasks and features three sub-datasets: FASDD_CV, FASDD_UAV, and FASDD_RS. These sub-datasets comprise cross-domain images from ground-based, airborne, and spaceborne sensors, respectively. Extensive experiments using advanced Swin Transformer models demonstrate satisfactory fire detection performance, with mAP scores of 84.9%, 89.7%, and 74.0% on the respective sub-datasets. Notably, the application case in wildfire localization highlights the proficiency of FASDD_RS models for monitoring and tracking forest fires. Trained on FASDD_RS, FASDD_UAV, and FASDD_CV, deep learning models can be individually deployed on edge devices including satellites, drones, and terrestrial sensors, thus empowering collaborative fire warning within the space-air-ground integrated observation network. Additionally, a standardized procedure for data preparation, data procedure, and quality assurance is established, providing off-the-shelf annotations with four common configurations to facilitate machine learning model training. FASDD stands as a pivotal benchmark, providing valuable resources for training and evaluating deep learning fire detection models, especially Large Vision Models (LVM). It holds the potential to accelerate research progress in urban firefighting or forest fire detection, providing vital security measures for early fire warning and emergency response tasks.

Prospects of buffer layer optimization for electrodeposited CZTS-based thin-film solar cell using SCAPS-1D

Kesterite Cu2ZnSnS4 (CZTS) has recently attracted the intensive attention of researchers as a significant photovoltaic material for the scalable production of thin film solar cells. We have particularly focused on replacing the conventional CdS buffer layer with non-toxic and earth-abundant materials of zinc stannate (Zn2SnO[Formula: see text] in environmentally friendly thin-film solar cells based on CZTS. Zinc stannate (ZTO) with a wide bandgap energy of about 3.33[Formula: see text]eV can be a promising material to reduce photon absorption loss and improve the photovoltaic performance of the device. Thus, the absorber and buffer layers were practically prepared to determine the bandgaps of layers for citation in SCAPS-1D simulation program. We employed chemical methods to deposit the CdS and CZTS layers and succeeded to obtain a high-quality kesterite phase of CZTS. The common configuration of FTO/CZTS/buffer/ZnO/AZO was the basis of the simulations in which, the thicknesses of the absorber and buffer layers were optimized by using the SCAPS-1D. According to the outcome of the simulations, the ZTO buffer layer has a better performance than CdS.

Band gap study of periodic piezoelectric micro-composite laminated plates by finite element method and its application in feedback control

Phononic crystals are materials or structures with periodic variations of elastic constants and density. Elastic waves in phononic crystals cannot propagate within a certain frequency range, called the band gap, due to the interference of their internal structure. This article investigates how fiber orientation affects the band gap properties of periodic micro-composite laminated plates. We examined the impact of five common composite laminate configurations on the system’s band gap and discovered that the antisymmetric configuration had superior high-frequency band gap performance. Based on this finding, we further explored how the antisymmetric angle influenced the system’s band gap. Since the study was conducted at a micro scale, micro structural effects were considered. Therefore, we used the modified coupled stress elastic dynamics and a four-node quadrilateral non-conforming element to discretize the micro composite laminated plate model, which had the nodal compatibility of high-order elasticity theory. Moreover, we employed feedback control to the proposed structure to dynamically adjust the band gap width according to different practical needs. This research supports the design of periodic micro-composite laminated plates and the piezoelectric feedback control system, which can control the vibration and wave propagation behaviors of micro structures using coupled piezoelectric sensors and actuators. The piezoelectric feedback control employed two control methods: direct proportional control and acceleration control. This article compared the single and multiple control methods of these two approaches to determine the optimal control strategy.

Use of a Krackow suture technique with PEEK barrel augmentation for subscapularis repair is stronger than use of a Mason-Allen suture technique

BackgroundIn total shoulder arthroplasty, the subscapularis tendon is routinely mobilized, by tenotomy, peel, or lesser tuberosity osteotomy, to visualize the joint and allow proper implant positioning. Careful mobilization of the subscapularis is undertaken to achieve an anatomic tension-free repair. This cadaveric study tests the biomechanical differences of 2 repair techniques of the subscapularis peel (SP) compared to the classically described technique. We hypothesize that adaptation of this SP technique using a custom-designed polyether-ether-ketone (PEEK) barrel in the bicipital groove may further stabilize suture repair of the subscapularis. MethodsTwenty paired cadaveric shoulder specimens underwent SP and repair via transosseous suture fixation. The PEEK barrel used was a laboratory prototype designed for the study (Catalyst OrthoScience, Naples, FL, USA). Five specimens were repaired using a traditional Mason-Allen suture; their paired shoulders were repaired using the PEEK barrel and a Mason-Allen suture. Five specimens were repaired using the Krackow suture; their paired shoulders were repaired using the PEEK barrel and a Krackow suture. Mechanical testing was performed using a uni-axial materials testing system with primary outcome of gap displacement and secondary outcomes of maximum load to failure and method of failure. ResultsThe Krackow repair method with and without PEEK augmentation was significantly stiffer than the Mason-Allen repair method with and without PEEK augmentation (P < .001 across all groups). Adding augmentation changed the strength of the Mason-Allen repair without achieving statistical significance (P = .0925). Intergroup differences in cyclic displacement were not statistically significant. The Krackow repair methods had higher mean maximal load at failure than the Mason-Allen repairs of 534 ± 108 N and 266 ± 98 N, respectively (P < .001). Maximum load at 5 mm displacement was significantly different across groups (P = .004). Methods of failure in the Mason-Allen technique groups included knot and tendon failure, and in the Krackow technique groups included suture failure and lesser tuberosity fracture. ConclusionRepairing the subscapularis with a Krackow suture is significantly stronger than a Mason-Allen repair in stiffness as well as load to failure. The results reported here compare a Krackow suture with a more common Mason-Allen suture configuration, and demonstrate the application of PEEK augmentation to subscapularis repair techniques. This study can guide surgeon selection of an ideal subscapularis repair technique for stemmed or stemless total shoulder arthroplasty.

Influence of car front-end designs on motorcyclists’ trajectory in head-on and side-on-head crashes

Motorcyclists are highly vulnerable road users, and cars are one of their primary crash opponents. This study investigates the influence of car front-end designs on motorcyclist trajectory in head-on and side-on-head crashes. The analysis is based on a dataset of 120 multi-body crash simulations conducted using MADYMO and post-processed with MATLAB. An analysis of 1412 real-world Powered Two-Wheeler (PTW) to car accidents was conducted to determine the most common crash configurations and the associated ranges of the variables, such as vehicle speeds and contact points. Three PTW styles (sport-touring, scooter, and sport) and four car front-end designs (Sport utility vehicle (SUV), Family Car/Sedan (FCR), Roadster (RDS), and Multi-purpose vehicle (MPV)) were considered.The study examined the riders’ thrown distance in both collision types. It was observed that, regardless of the collision type, the head was identified overall as the primary body region coming into contact with the opposing vehicle, followed by the chest and neck. In frontal collisions, an augmented bonnet height corresponded to an increased incidence of head contact, whereas a lower bonnet height resulted in a higher frequency of chest contact. Moreover, the thrown distance depended also on PTW speed, particularly for sport and sport-touring motorcycles. Notably, contact with the car windscreen was only observed at velocities exceeding 60 km/h, whereas impact with the bonnet leading edge occurred exclusively below this threshold. Due to the shielding effect of their PTW’s fairing, scooter riders predominantly experienced no contact with the opposing vehicle. Sport-touring motorcycles exhibited a more vertical trajectory upon ejection, leading to a greater likelihood of overturning and subsequent rearward head impact with the vehicle. In contrast, sport motorcycles tended to forward projections with a high likelihood of chest contact. In the case of lateral impacts, it was observed that vehicles with a more prominent profile, such as SUVs and MPVs, equipped with protruding bumpers, effectively restrained riders. In this case, vehicle speed did not exert a significant influence on the thrown distance. Additionally, the presence of a conspicuous fuel tank and the initial posture of the rider on the PTW played a crucial role in determining the final thrown distance. Due to their upright postures and the absence of a pronounced fuel tank, scooter dummies were thrown further than others, thus causing head contact with the windscreen.These findings highlight the importance of car front-end design and PTW fairings in mitigating riders’ injuries and provide valuable insights to vehicle manufacturers for developing tailored safety measures for riders.

A generalized, model-free framework for assessing scour-induced bridge pier instability

Flood-induced scour is one of the leading causes of bridge failures in the United States, accounting for 53 % of recorded failures between 1989 and 2000. With many existing bridges considered “scour critical”, it is essential to closely monitor its development for effective mitigation. However, despite advances in scour hole measurement techniques, continuous monitoring of scour remains underused and little guidance is available to maintenance engineers to assess structural stability from scour depth measurements. This research presents a proof-of-concept, model-free bridge pier structural assessment framework. This framework is built on a library of bridge pier failure surfaces – curves that define failure limits for combinations of scour, wind, and flood loading for a range of structural configurations and site conditions. User input is limited to basic structural and site information, from which a corresponding failure surface is automatically selected, either directly or through interpolation between surfaces in the library. In this study, the creation of a failure surface library and framework is focused on pile bent pier designs, due to their widespread use. A broad scope of parameters was modeled such that common configurations of pier bent bridge designs and site conditions in Florida were considered. Sensitivity studies were performed to identify parameters for which modeling simplifications could be made to build the failure surface library with reduced computational burden. Results from three case study bridges are presented to verify that the resulting assessment framework maintained reasonable representation of structural response.

Experimental and numerical study on configuration, shape, distance and angle of attack in film cooling implementing vortex generator

The impact of vortex generator configuration, shape, angle of attack and distance between vortex generator and film cooling hole has been studied using both experimental and numerical methods for enhancing the gas turbine blade’s film cooling efficiency. Infrared (IR) thermography technique has been used for investigating the temperature field. In order to obtain the velocity field ANSYS FLUENT has been implemented. The diameter of the film cooling hole and the cross-flow velocity are used to calculate the Reynolds number, which is set at 2369. The blowing ratio of the jet to the cross-flow has been changed to 0.5, 1.0, and 1.5. Effect of CFU and common flow down configuration has been investigated. The angle of attack has been varied as 35° and 45°. It is observed that common flow down configuration of vortex generator performs better than Common Flow Up configuration. Common flow down configuration as well as lower distance between vortex generator and film cooling hole enhance the film cooling effectiveness due to generation of secondary longitudinal vortices which decrease the strength of the counter rotating vortex structures. Among all the shape (triangular, rectangular and trapezoidal) rectangular vortex generator performs better. Growths of shear layer vortices are modified due to the inclusion of vortex generator. Overall, Vortex Generator with common flow down configuration and 35° angle of attack performs better than Common Flow Up configuration due to generation of secondary longitudinal vortices which annihilates the counter rotating vortex structures due to having rotational tendency opposite to Counter rotating vortex pair.

Simulated Channel Length Variation Effects on Regulated Cascode Input Stage-Based Transimpedance Amplifier for Fiber Optics Applications

A proposed transimpedance amplifier with channel length variation is simulated. The amplifier consists of a regulated cascode input stage followed by a common gate-common source configuration. A channel length series (45 nm, 90 nm and 130 nm) in CMOS technology was introduced within the proposed amplifier in order to achieve comparative performance analysis. There are two key findings from this study. On one hand, it was found that the trade off in gain versus bandwidth and input referred noise current still applies when channel length is moved upward from 45 nm up to 130 nm. A series of transimpedance amplifier gains (42.16 dBΩ, 44.34 dBΩ and 46.25 dBΩ) that correspond to (1.80 GHz, 1.33 GHz and 1.06 GHz) of bandwidths is reported corresponding to the above channel length series respectively with an input referred noise current spectral density series (16.35 pA/sqrt(Hz), 12.17 pA/sqrt(Hz) and 10.60 pA/sqrt(Hz)) of reduction. On the other hand, a reduction in power consumption occurred as channel length is moved upward for the same proposed topology. A total power consumption series (0.611 mW, 0.287 mW and 0.173 mW) was reported that corresponds to the above channel length series.

New species of Rockacestus (Cestoda, Phyllobothriidea) from skates of the genus Bathyraja (Rajiformes, Arhynchobatidae) in the Southwestern Atlantic Ocean with comments on the distribution of the genus

Three new species of Rockacestus Caira, Bueno &amp; Jensen, 2021 were recovered from arhynchobatid skates taken between 37°S–55°S in the Magellanic Province, Southwestern Atlantic Ocean. Rockacestus blasisp. nov. was found in Bathyraja macloviana (Norman, 1937), whereas Rockacestus magellanicussp. nov., and Rockacestus ottavianoisp. nov. were found in Bathyraja magellanica (Philippi, 1902). These species differ from their congeners in having a particular combination of anatomical features, including a moderate to highly folded bothridia, presence of a uteroduct, and a seminal receptacle. Cross-sections of mature proglottids were made for the first time in members of the genus. In addition, the microthrix pattern was described in detail, focusing on the distal bothridial surface, including the apical sucker and marginal loculi resulting in a common microthrix configuration with filitriches and small lanceolate, lingulate, and a particular kind of coniform spinitriches. The diagnosis of Rockacestus is revised to include several features exhibited by the new species. The distribution data of the species currently assigned to Rockacestus are compiled and updated. The finding of R. blasisp. nov., R. magellanicussp. nov., and R. ottavianoisp. nov. not only increases the number of members of Rockacestus in the Magellanic Province in the Southwestern Atlantic from one to four but also expands our knowledge of phyllobothriideans and their association with the softnose skates of the genus Bathyraja Ishiyama, 1958 in the Southern Hemisphere.

TESS Photometry of AM Her and AR UMa: Binary Parameters, Cyclotron Emission Modeling, and Mass Transfer Duty Cycles

Transiting Exoplanet Survey Satellite (TESS) photometry of the polars AM Herculis (AM Her) and AR Ursae Majoris (AR UMa) is presented, along with high-speed photometry. AM Her shows a variety of high states with frequent transitions between them. TESS photometry of AR UMa in the low state reveals no evidence of accretion, while the McDonald 2.1 m telescope caught AR UMa in its high accretion state. Roche-lobe overflow is shut off during low states of AR UMa, while accretion often still takes place during low states of AM Her. We derive inclinations of 50° and 70° for AM Her and AR UMa respectively. To model the high-state light curves of AM Her, we employ a self-organized map light-curve classification scheme to establish common accretion configurations. The cyclotron radiation properties then allow the production of emission region maps on the surface of the white dwarf. The accretion geometry of AM Her is most consistent with a multipolar field structure. The high-state photometry of AR UMa has stochastic accretion flaring, which we attribute to magnetically buffeted mass transfer through the inner Lagrangian point L1. To consider this possibility, we examine the magnetism of both stars and argue that the local magnetic field near L1 can initiate short-lived accretion events and affect transitions between high and low accretion states in both AM Her and AR UMa. In particular, AR UMa has the low state as its default, while AM Her and most other active polars are in the high state by default.

Analysis of vortex mixing in passive micromixers with misaligned inlet and rectangular winglets

In the present study, a three-dimensional design of a passive micromixer is proposed which induces the swirling flow pattern by employing the misaligned inlets and winglets. The concepts of fluid stretching and twisting are utilized to improve the mixing efficiency. Stretching is quantified in terms of the modified flow tortuosity parameter. The dependence of various geometrical parameters on flow tortuosity is examined to increase the diffusive mixing by increasing the lateral Peclet number. A detailed analysis is carried out to understand the impact of geometrical features on the vortex formation, propagation, and intensification. Lambda 2 and the helicity approach are used to identify the vortex core region and quantified using a modified swirl number & vortex index. For vortex T misalignment, the aspect ratio 1 along with the staggered common flow-down configuration of winglets is highly effective. For misaligned Y inlet, both interfacial diffusive mixing along with longitudinal vortices at winglets generate highly effective mixing even at a low Reynolds number. For Reynolds number 1 to 70 and channel length 3.5 mm, mixing efficiency above 82% is achieved, and the mixing energy cost is subsequently reduced. A detailed comparative study is done to establish the effectiveness of the present design.

A Comparative Analysis of Aerodynamic Performance: Straight Fin and Curved Fin Rockets using Computational Fluid Dynamics (CFD)

This investigation seeks to discern the aerodynamic differentials between rockets featuring straight fins and those with curved fins, focusing on the drag coefficient (cd), lift coefficient (cl), and moment coefficient (cm). Employing the computational fluid dynamics (CFD) methodology within ANSYS Fluent software, the research endeavors to provide comprehensive insights. The rockets under scrutiny share a common cylindrical body configuration, boasting a 70 mm diameter, a conical nose, and four symmetrically positioned fins along the lower body. The CFD analyses encompass subsonic Mach 0.6 and supersonic Mach 1.2 scenarios, with the angle of attack systematically varying from 0° to 25° at 5° intervals for each velocity setting. The outcomes of the simulations reveal notable trends: both cd and cl exhibit an upward trajectory, while cm experiences a decrement with escalating angles of attack and velocities. The culmination of Ansys CFD simulations for both rocket configurations unequivocally indicates superior flight performance for the straight fin rocket. This discernment is grounded in the observed amplification of drag and lift coefficients, coupled with the concomitant reduction in the moment coefficient, thus elucidating the nuanced aerodynamic distinctions between straight fin and curved fin rockets across varying flight conditions.

Methodology for Evaluating a Distributed Variable-Camber Trailing-Edge System in Preliminary Aircraft Design

A controlled adjustment of the wing camber during cruise flight by an extension of each separate flap allows for wing shape optimization, depending on the current mission point including the prevailing conditions, contributing to an increase in efficiency. This is referred to as variable camber (VC). This paper aims to investigate a methodology for a retrofit application of VC technology with differential flap setting, especially for a segmented trailing-edge system at the overall aircraft level in the preliminary design phase. In addition, an assessment is conducted to clarify whether actuation on the basis of a central shaft system or a decentralized power-by-wire system is advantageous. The investigation is based on a commercial aircraft with a maximum takeoff mass of 270 t and compares the potential of a VC application with an aerostructural twist optimization of the wing. Different configurations of the trailing-edge flaps, ranging from a common two-flap configuration up to a configuration with six trailing-edge devices, are covered in order to give a holistic implementation recommendation, including actuation and flap segmentation. Depending on the reference aircraft, the study shows a considerable fuel-saving potential for VC applications, e.g., 3.5% for the pre-optimized reference on a long-range mission.

Numerical Study of Thermal Performance on Fin and Tube Heat Exchanger with Flat Rectangular and Sinusoidal Winglet Vortex Generators

Generation of vortices in the fin and tube heat exchanger is one of the common methods to reduce the air-side thermal resistance. This study deals with the enhancement of heat transfer in the air side using conventional rectangular and sinusoidal sine wave vortex generators. The vortex generators are placed in the downstream location of the tube in the common flow-down configurations and the range of Reynolds number is maintained about 400 to 1100. The results of the above vortex generators are compared with baseline configuration based on thermos-hydraulic criterion parameters like variation in the flow structure, variation in the temperature distribution, variation in the pressure distribution, variation in the friction factor, and overall thermal enhancement factor. Based on the comparative numerical analysis, sinusoidal and conventional rectangular winglet shows good heat transfer enhancement in that they have a large pressure loss penalty.

Design of infiltration swales

Conventional designs of infiltration swales either neglect infiltration while the swale is filling or approximate the flow in the swale as being normal instead of gradually varied. The adequacy of these approximations are elucidated, and two common design configurations for infiltration swales are considered. For swales designed to store the water-quality volume behind check dams, the retained volume can be on the order of twice the design water-quality volume depending on the magnitude of the inflow rate normalized by the infiltration rate. In a second configuration, the swale is designed to infiltrate the water-quality flow, where the limiting assumption is that the flow is normal along the infiltration length. The actual required infiltration length can be expressed as a function of the normalized bottom width, and the required infiltration length can be up to 30% longer than derived using the conventional design. Graphical relations are developed that can be used to either quantify the factor of safety of conventional designs or provide credit for in the flood-control function of infiltration swales.