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Sample records for active suichoku fin

  1. Introduction of anti-rolling active vertical fin and its application to maneuverability for displacement-type super high speed ship. 2nd Report.; Haisuiryogata chokosokusen no yokoyure seishiyo active suichoku fin no donyu to sojuseieno oyo

    Hirayama, T.; Saito, Y. [Yokohama National University, Yokohama (Japan). Faculty of Engineering; Niihara, Y. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1996-12-31

    Discussed herein are the effects of vertical fin projecting downwards from the bottom of a displacement-type superhigh-speed ship, installed to improve its transverse stability and turning ability. The system for simultaneously controlling rudder and vertical fin by the optimum regulator was studied for maneuverability in directional following waves and smooth water, and maneuverability was simulated numerically. A ship is greatly rolled and sloped when running in waves. It is found that the vertical fin shows a high anti-rolling effect when the ship runs straight. The optimum regulator greatly improves maneuverability in waves, reducing rolling by 92%. Increased rolling with the vertical fin, observed in the previous study in directional following waves, is found to be due to the rudder. The optimum position of the fin is determined to control transverse sloping of a turning ship in a superhigh-speed region. 21 refs., 12 figs., 4 tabs.

  2. Muscle activity and hydrodynamic function of pelvic fins in trout (Oncorhynchus mykiss).

    Standen, E M

    2010-03-01

    Contrary to the previous premise that pelvic fins lacked obvious function, recent work on three-dimensional fin motions suggests that pelvic fins actively control stability and speed in slowly swimming trout. This study used electromyography to measure pelvic fin muscle activity and particle imaging velocimetry to quantify flow along the ventral body region to test this hypothesis. Fish swam at slow speeds (0.13-1.36 BL s(-1)) while being filmed with three high speed cameras. Three-dimensional kinematics were captured for all trials. During EMG trials pelvic fin muscle activity was synchronized to kinematic motion, during particle imaging velocimetry trials, a laser light-sheet was used to visualize the flow surrounding the ventral aspect of the fish. Four main conclusions are reached: first, pelvic fins are actively oscillated during slow-speed swimming; antagonistic abductor and adductor muscles contracted simultaneously, their collective action producing a unique contralateral oscillating behaviour in the fins. Second, pelvic fins slow the flow along the ventral side affecting pitch and yaw instabilities; flow upstream of the pelvic fins is slowed by 0.02 m s(-1) and flow downstream of the pelvic fins is slowed by 0.034 m s(-1) compared with free stream flow. Third, pelvic fin wake influences anal fin angle of attack; flow angle in the wake of the pelvic fin was 33.84+/-2.4 deg. (max) and -11.83+/-11.2 deg. (min) compared with the free stream flow angle of 1.27+/-0.1 deg. Fourth, pelvic fins appear to actively damp body oscillation during slow-speed swimming, providing drag to help control speed and stabilize the body position during slow-speed swimming. PMID:20154199

  3. Assessment of in vitro antifungal activity of preparation ''fin Candimis'' against Candida strains

    Anna Głowacka

    2013-12-01

    Full Text Available The aim of the study was to assess the antifungal activity of preparation „fin Candimis” (oregano essential oil against yeast-like strains belonging to the genus Candida. During the investigation, there were used up nine Candida albicans strains and ten C. glabrata strains isolated from different clinical material, along with one C. albicans demonstration strain ATCC 90028. The oregano essential oil, utilized in the study, was obtained from fresh leaves of Origanum vulgare L. and bore a trade name „fin Candimis”. According to data yielded by its manufacturer, concentration of pure oregano essential oil in preparation „fin Candimis” totals up to 210 mg/ml. The susceptibility of the Candida strains to preparation „fin Candimis” was assessed by means of the disc-diffusion method, upon the Sabouraud solid medium (after a 24-hour incubation of the cultures at temperature of 37 degrees centigrade; the oregano essential oil had been diluted in 1 ml of DMSO, according to the geometrical progression. A measure of the antifungal activity of preparation „fin Candimis” was the minimal inhibitory concentration (MIC, in terms of the fungus growth. Preparation „fin Candimis” is capable of being applied in the prevention and treatment of candidiasis – alone, or as a natural adjunctive agent. The C. albicans strains are more susceptible to preparation „fin Candimis” in comparison to the C. glabrata ones.

  4. Mechanosensation in an adipose fin.

    Aiello, Brett R; Stewart, Thomas A; Hale, Melina E

    2016-03-16

    Adipose fins are found on approximately 20% of ray-finned fish species. The apparently rudimentary anatomy of adipose fins inspired a longstanding hypothesis that these fins are vestigial and lack function. However, adipose fins have evolved repeatedly within Teleostei, suggesting adaptive function. Recently, adipose fins were proposed to function as mechanosensors, detecting fluid flow anterior to the caudal fin. Here we test the hypothesis that adipose fins are mechanosensitive in the catfish Corydoras aeneus. Neural activity, recorded from nerves that innervate the fin, was shown to encode information on both movement and position of the fin membrane, including the magnitude of fin membrane displacement. Thus, the adipose fin of C. aeneus is mechanosensitive and has the capacity to function as a 'precaudal flow sensor'. These data force re-evaluation of adipose fin clipping, a common strategy for tagging fishes, and inform hypotheses of how function evolves in novel vertebrate appendages. PMID:26984621

  5. Design and analysis of a plate-fin sandwich actively cooled structural panel

    Smith, L. M.

    1978-01-01

    The skin structure of hydrogen fueled hypersonic transport vehicles traveling at Mach 6 and above must be designed to withstand, for relatively long periods of time, the aerodynamic heating effects which are far more severe than those encountered by the supersonic aircraft of today. The use of conventional aircraft materials such as aluminum in combination with forced convection active cooling to accommodate aerodynamic heating is addressed. The basic active cooling concept consists of a stringer stiffened plate-fin sandwich. The sandwich surface is subjected to the aerodynamic heat flux which is transferred, via convection, to a coolant that is forced through the sandwich under pressure. The coolant, in turn, circulates in a closed loop through a hydrogen heat exchanger and back through the skin panel.

  6. Study of plate-fin heat exchanger and cold plate for the active thermal control system of Space Station

    Chyu, MING-C.

    1992-01-01

    Plate-fin heat exchangers will be employed in the Active Thermal Control System of Space Station Freedom. During ground testing of prototypic heat exchangers, certain anomalous behaviors have been observed. Diagnosis has been conducted to determine the cause of the observed behaviors, including a scrutiny of temperature, pressure, and flow rate test data, and verification calculations based on such data and more data collected during the ambient and thermal/vacuum tests participated by the author. The test data of a plate-fin cold plate have been also analyzed. Recommendation was made with regard to further tests providing more useful information of the cold plate performance.

  7. Antioxidant and Antiproliferative Activities of Heated Sterilized Pepsin Hydrolysate Derived from Half-Fin Anchovy (Setipinna taty

    Dongfeng Wang

    2011-06-01

    Full Text Available In this paper we studied the antioxidant and antiproliferative activities of the heated pepsin hydrolysate from a marine fish half-fin anchovy (HAHp-H. Furthermore, we compared the chemical profiles including the amino acid composition, the browning intensity, the IR and UV-visible spectra, and the molecular weight distribution between the half-fin anchovy pepsin hydrolysate (HAHp and HAHp-H. Results showed that heat sterilization on HAHp improved the 1,1-diphenyl-2-picryl-hydrazil (DPPH radical-scavenging activity and reducing power. In addition, the antiproliferative activities were all increased for HAHp-H on DU-145 human prostate cancer cell line, 1299 human lung cancer cell line and 109 human esophagus cancer cell line. The contents of free amino acid and reducing sugar of HAHp-H were decreased (P < 0.05. However, hydrophobic amino acid residues and the browning intensity of HAHp-H were increased. FT-IR spectroscopy indicated that amide I and amide III bands of HAHp-H were slightly modified, whereas band intensity of amide II was reduced dramatically. Thermal sterilization resulted in the increased fractions of HAHp-H with molecular weight of 3000–5000 Da and below 500 Da. The enhanced antioxidant and antiproliferative activities of HAHp-H might be attributed to the Maillard reaction.

  8. Fins coloration of perch in relation to external activity concentration of radionuclides

    The Techa River is significantly polluted by radionuclides. This time the content of 90Sr varies from 5 Bq/l in water of lower Techa to 40 Bq/l in higher Techa, and the concentration of 137Cs fluctuates from background content to 0,5 Bq/l, and tritium from 100 Bq/l to 450 Bq/l. Miass River are not polluted in the same extent. The perch in these rivers are suitable for examine the potential effect of environmental perturbation on carotenoid based coloration. As vertebrates could not produce carotenoids themselves, and would use more carotenoids due to oxidative stress when exposed radiation, we hypothesized that fish caught in upper part of Techa River will be more pale than fish from lower part and the control river Miass. We used a cost effective method to estimate coloration by photographing the fins in standardized setting. The measuring of fish fins as performed under standardized condition by Adobe Photoshop software in color spaces CIE 1976 L*a*b* and sRGB IEC61966-2.1 was used. In sRGB color space the values of Red, Green, Blue channels were measured and an average wave length was calculated as a function of three elementary light streams of different intensity, appeared as reflection from a fin. In L*a*b color space the values of *a and *b channels shows the position of a color in a color space. To evaluate the red color of a perch fin the most usable channel is the *a channel which shows the position of the color on the red-green axis. Due to low sample size we pooled males and females in our analysis. We used three different station in the Techa: RT-1 in the higher Techa, RT-2 in the middle Techa, and RT-3 in lower Techa. As a control group was taken the fish from Miass river (RM station). Our results shows that perch from RT-3 (570.7 nm) significantly differ in coloration from the perch from RT-2 and RT-1 (p=0.00001 and p=0.0014 respectively, hereinafter used Kruskal-Wallis rank sum test with Nemenyi-Damico-Wolfe-Dunn test as post-hoc criterion, number

  9. Fins coloration of perch in relation to external activity concentration of radionuclides

    Yegoreichenkov, E.; Pryakhin, E. [Urals Research Center for Radiation Medicine (Russian Federation); Rudolfsen, G. [Norwegian Radiation Protection Authority and University of Tromsoe (Norway)

    2014-07-01

    The Techa River is significantly polluted by radionuclides. This time the content of {sup 90}Sr varies from 5 Bq/l in water of lower Techa to 40 Bq/l in higher Techa, and the concentration of {sup 137}Cs fluctuates from background content to 0,5 Bq/l, and tritium from 100 Bq/l to 450 Bq/l. Miass River are not polluted in the same extent. The perch in these rivers are suitable for examine the potential effect of environmental perturbation on carotenoid based coloration. As vertebrates could not produce carotenoids themselves, and would use more carotenoids due to oxidative stress when exposed radiation, we hypothesized that fish caught in upper part of Techa River will be more pale than fish from lower part and the control river Miass. We used a cost effective method to estimate coloration by photographing the fins in standardized setting. The measuring of fish fins as performed under standardized condition by Adobe Photoshop software in color spaces CIE 1976 L*a*b* and sRGB IEC61966-2.1 was used. In sRGB color space the values of Red, Green, Blue channels were measured and an average wave length was calculated as a function of three elementary light streams of different intensity, appeared as reflection from a fin. In L*a*b color space the values of *a and *b channels shows the position of a color in a color space. To evaluate the red color of a perch fin the most usable channel is the *a channel which shows the position of the color on the red-green axis. Due to low sample size we pooled males and females in our analysis. We used three different station in the Techa: RT-1 in the higher Techa, RT-2 in the middle Techa, and RT-3 in lower Techa. As a control group was taken the fish from Miass river (RM station). Our results shows that perch from RT-3 (570.7 nm) significantly differ in coloration from the perch from RT-2 and RT-1 (p=0.00001 and p=0.0014 respectively, hereinafter used Kruskal-Wallis rank sum test with Nemenyi-Damico-Wolfe-Dunn test as post

  10. Dorsal fin anatomy (Cetacean dorsal fin Anatomy)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cetacean dorsal fin Anatomy for ONR. Comparison within populations to ascertain phenotypic differences. Findings corroborate field observation. dorsal fin description

  11. Optimal design study of cylindrical finned reactor for solar adsorption cooling machine working with activated carbon-ammonia pair

    This paper presents a model describing the heat and mass transfer in cylindrical finned reactor of solar adsorption refrigerator. Giving the meteorological data as boundary conditions on the reactor; the model computes the solar coefficient of performance (COPs). The validity of the model has been tested by using experimental results. An analysis of the sensitivity of the COPs versus the geometrical parameters of the reactor (radius of the reactor, fins thickness and fins number) is mad. Then the model is applied to optimize the solar reactor. The COPs is used as an optimization criterion. The geometrical parameters where the COPs of the machine reach a maximum have been calculated

  12. Do culinary preparations influence 210Po activity concentration in fin fishes?

    Polonium-210, a member of the 238U series, is a major source of internal radiation dose to marine organisms and human beings. This naturally occurring radionuclide is responsible for a considerable proportion of radiation exposure of humans, in particular, through consumption of seafood. Considering all these facts, many countries and various international agencies have carried out studies for assessing the levels of 210Po globally. The volatile nature of 210Po at high temperatures would significantly reduce its activity concentration in various culinary preparations of seafood. Some studies of fishes have shown no measurable reduction in 210Po activity in culinary preparations and some authors have reported measurable increase. Based on this scenario, the present study was aimed at estimating 210Po activity concentrations in different culinary preparations of fishes traditionally prevalent in the coastal region of southern Tamil Nadu. The commonly available fish species (Sardinella sp., Leiognathus sp., Katsuwonus sp., Stolephorus sp. and Chirocentrus sp.) consumed more by the people of this region were collected from nearby fish-landing centre (Kanyakumari and Manakudi). The samples were washed thoroughly with tap water and eviscerated. The fillets were divided into four groups. Fresh fillets analysed as such; A portion of the sample was subjected to oil-frying (with commonly used spices and salt); One portion of the sample was salt-dried; Another portion of the sample was boiled (curry) along with common spices and salt. Ten to twenty grams of each sample was subjected to wet-digestion using 70% conc. HNO3 followed by the addition of 40% H2O2

  13. Evaluation of beta spectrometry for environmental monitoring of undeclared nuclear activities. Report on task FIN A846 on the Finnish support programme to IAEA safeguards

    The IAEA (the Agency) is considering environmental monitoring as a possible method to detect the presence of undeclared nuclear activities in a country covered by a comprehensive safeguards agreement. The Finnish support program (FINSP), implemented by the Finnish Centre for Radiation and Nuclear Safety (STUK), is supporting the Agency in this new programme. This Agency Task FIN A 846, addresses the possibility of using beta-emitting nuclides as indicators for covert nuclear fuel reprocessing activities. (90 refs., 1 fig., 12 tabs.)

  14. FIN 200 UOP Course Tutorial / fin200dotcom

    anil14

    2015-01-01

    FIN 200 Entire Course For more course tutorials visit   www.fin200.com   FIN 200 Week 1 CheckPoint Financial Management Goals FIN 200 Week 1 Assignment Cash Flow Preparation FIN 200 Week 2 Checkpoint Financial Ratios FIN 200 Week 2 DQ 1 & DQ 2 FIN 200 Week 3 CheckPoint Financial Forecasting FIN 200 Week 3 Assignment Pro Forma Statements FIN 200 Week 4 Checkpoint Break Even Analysis FIN 200 Week 4 DQ 1 & DQ 2 FIN 200 Week 5 CheckPo...

  15. FIN 200 Uop Material-fin200dotcom

    Sandywilliam6

    2015-01-01

    FIN 200 Entire Course For more course tutorials visit   www.fin200.com   FIN 200 Week 1 CheckPoint Financial Management Goals FIN 200 Week 1 Assignment Cash Flow Preparation FIN 200 Week 2 Checkpoint Financial Ratios FIN 200 Week 2 DQ 1 & DQ 2 FIN 200 Week 3 CheckPoint Financial Forecasting FIN 200 Week 3 Assignment Pro Forma Statements FIN 200 Week 4 Checkpoint Break Even Analysis FIN 200 Week 4 DQ 1 & DQ 2 FIN 200 Week 5 CheckPo...

  16. FIN 415 Uop Material-fin415dotcom

    Sandywilliam1

    2015-01-01

    FIN 415 Entire Course For more course tutorials visit www.fin415.com   FIN 415 Week 1 Individual Assignment Risk Management Overview Paper FIN 415 Week 2 Team Assignment Risk Management Identification and Assessment Paper FIN 415 Week 3 Individual Assignment Risk Management Techniques Paper FIN 415 Week 3 Individual Assignment Risk Management Problem, Set I FIN 415 Week 3 Team Assignment Risk Measurement Summary FIN 415 Week 4 Individual Assignment Ris...

  17. Shark's Fin Soup

    2000-01-01

    Ingredients: 250g semi-finished shark's fin (removed of bone, skin and dipped in water), 100g ham, 100g chicken, 50g pork shoulder, 50g dried scallops, 100g bean sprouts, salt and MSG (optional). Method: 1. Scald the shark's fin in boiling water. 2. Fill a pot with water and add the chicken, pork and most of the

  18. Fish locomotion: kinematics and hydrodynamics of flexible foil-like fins

    Lauder, George V.; Madden, Peter G. A.

    2007-11-01

    The fins of fishes are remarkable propulsive devices that appear at the origin of fishes about 500 million years ago and have been a key feature of fish evolutionary diversification. Most fish species possess both median (midline) dorsal, anal, and caudal fins as well as paired pectoral and pelvic fins. Fish fins are supported by jointed skeletal elements, fin rays, that in turn support a thin collagenous membrane. Muscles at the base of the fin attach to and actuate each fin ray, and fish fins thus generate their own hydrodynamic wake during locomotion, in addition to fluid motion induced by undulation of the body. In bony fishes, the jointed fin rays can be actively deformed and the fin surface can thus actively resist hydrodynamic loading. Fish fins are highly flexible, exhibit considerable deformation during locomotion, and can interact hydrodynamically during both propulsion and maneuvering. For example, the dorsal and anal fins shed a vortex wake that greatly modifies the flow environment experienced by the tail fin. New experimental kinematic and hydrodynamic data are presented for pectoral fin function in bluegill sunfish. The highly flexible sunfish pectoral fin moves in a complex manner with two leading edges, a spanwise wave of bending, and substantial changes in area through the fin beat cycle. Data from scanning particle image velocimetry (PIV) and time-resolved stereo PIV show that the pectoral fin generates thrust throughout the fin beat cycle, and that there is no time of net drag. Continuous thrust production is due to fin flexibility which enables some part of the fin to generate thrust at all times and to smooth out oscillations that might arise at the transition from outstroke to instroke during the movement cycle. Computational fluid dynamic analyses of sunfish pectoral fin function corroborate this conclusion. Future research on fish fin function will benefit considerably from close integration with studies of robotic model fins.

  19. Function of dorsal fins in bamboo shark during steady swimming.

    Maia, Anabela; Wilga, Cheryl A

    2013-08-01

    To gain insight into the function of the dorsal fins in white-spotted bamboo sharks (Orectolobiformes: Hemiscyillidae) during steady swimming, data on three-dimensional kinematics and electromyographic recordings were collected. Bamboo sharks were induced to swim at 0.5 and 0.75 body lengths per second in a laminar flow tank. Displacement, lag and angles were analyzed from high-speed video images. Onset, offset, duration, duty cycle and asynchrony index were calculated from three muscle implants on each side of each dorsal fin. The dorsal fins were displaced more laterally than the undulating body. In addition, the dorsal tips had larger lateral displacement than the trailing edges. Increased speed was accompanied by an increase in tail beat frequency with constant tail beat amplitude. However, lateral displacement of the fins and duration of muscle bursts remained relatively constant with increased speed. The range of lateral motion was greater for the second dorsal fin (mean 33.3°) than for the first dorsal fin (mean 28.4°). Bending within the fin was greater for the second dorsal fin (mean 43.8°) than for the first dorsal fin (mean 30.8°). Muscle onset and offset among implants on the same side of each dorsal fin was similar. Three-dimensional conformation of the dorsal fins was caused by interactions between muscle activity, material properties, and incident flow. Alternating bilateral activity occurred in both dorsal fins, further supporting the active role of these hydrofoils in thrust production during steady swimming. The dorsal fins in bamboo sharks are capable of thrust production during steady swimming and do not appear to function as stabilizing structures. PMID:23830781

  20. Touch sensation by pectoral fins of the catfish Pimelodus pictus.

    Hardy, Adam R; Steinworth, Bailey M; Hale, Melina E

    2016-02-10

    Mechanosensation is fundamental to many tetrapod limb functions, yet it remains largely uninvestigated in the paired fins of fishes, limb homologues. Here we examine whether membranous fins may function as passive structures for touch sensation. We investigate the pectoral fins of the pictus catfish (Pimelodus pictus), a species that lives in close association with the benthic substrate and whose fins are positioned near its ventral margin. Kinematic analysis shows that the pectoral fins are held partially protracted during routine forward swimming and do not appear to generate propulsive force. Immunohistochemistry reveals that the fins are highly innervated, and we observe putative mechanoreceptors at nerve fibre endings. To test for the ability to sense mechanical perturbations, activity of fin ray nerve fibres was recorded in response to touch and bend stimulation. Both pressure and light surface brushing generated afferent nerve activity. Fin ray nerves also respond to bending of the rays. These data demonstrate for the first time that membranous fins can function as passive mechanosensors. We suggest that touch-sensitive fins may be widespread in fishes that maintain a close association with the bottom substrate. PMID:26865307

  1. Hydrodynamic function of dorsal and anal fins in brook trout (Salvelinus fontinalis).

    Standen, E M; Lauder, G V

    2007-01-01

    Recent kinematic and hydrodynamic studies on fish median fins have shown that dorsal fins actively produce jets with large lateral forces. Because of the location of dorsal fins above the fish's rolling axis, these lateral forces, if unchecked, would cause fish to roll. In this paper we examine the hydrodynamics of trout anal fin function and hypothesize that anal fins, located below the fish's rolling axis, produce similar jets to the dorsal fin and help balance rolling torques during swimming. We simultaneously quantify the wake generated by dorsal and anal fins in brook trout by swimming fish in two horizontal light sheets filmed by two synchronized high speed cameras during steady swimming and manoeuvring. Six major conclusions emerge from these experiments. First, anal fins produce lateral jets to the same side as dorsal fins, confirming the hypothesis that anal fins produce fluid jets that balance those produced by dorsal fins. Second, in contrast to previous work on sunfish, neither dorsal nor anal fins produce significant thrust during steady swimming; flow leaves the dorsal and anal fins in the form of a shear layer that rolls up into vortices similar to those seen in steady swimming of eels. Third, dorsal and anal fin lateral jets are more coincident in time than would be predicted from simple kinematic expectations; shape, heave and pitch differences between fins, and incident flow conditions may account for the differences in timing of jet shedding. Fourth, relative force and torque magnitudes of the anal fin are larger than those of the dorsal fin; force differences may be due primarily to a larger span and a more squarely shaped trailing edge of the anal fin compared to the dorsal fin; torque differences are also strongly influenced by the location of each fin relative to the fish's centre of mass. Fifth, flow is actively modified by dorsal and anal fins resulting in complex flow patterns surrounding the caudal fin. The caudal fin does not encounter

  2. FIN 200 (UOP) course tutorial/tutorialoutlet

    naresh 1

    2015-01-01

    For more course tutorials visit www.tutorialoutlet.com     FIN 200 Week 1 CheckPoint Financial Management Goals (UOP) FIN 200 Week 1 Assignment Cash Flow Preparation (UOP) FIN 200 Week 2 Checkpoint Financial Ratios (UOP) FIN 200 Week 2 DQ 1 & DQ 2 (UOP) FIN 200 Week 3 CheckPoint Financial Forecasting (UOP) FIN 200 Week 3 Assignment Pro Forma Statements (UOP) FIN 200 Week 4 Checkpoint Break Even Analysis (UOP) FIN 200 Week 4 DQ 1 & ...

  3. Silicon LEDs in FinFET technology

    Piccolo, G.; Kuindersma, P.I.; Ragnarsson, L-A.; Hueting, R.J.E.; Collaert, N.; Schmitz, J.

    2014-01-01

    We present what to our best knowledge is the first forward operating silicon light-emitting diode (LED) in fin-FET technology. The results show near-infrared (NIR) emission around 1100 nm caused by band-to-band light emission in the silicon which is uniformly distributed across the lowly doped activ

  4. FIN 200 UOP COURSE Tutorial/UOPHELP

    sdfghj

    2015-01-01

    For more course tutorials visit www.uophelp.com   FIN 200 Week 1 CheckPoint Financial Management Goals FIN 200 Week 1 Assignment Cash Flow Preparation FIN 200 Week 2 Checkpoint Financial Ratios FIN 200 Week 2 DQ 1 & DQ 2 FIN 200 Week 3 CheckPoint Financial Forecasting FIN 200 Week 3 Assignment Pro Forma Statements FIN 200 Week 4 Checkpoint Break Even Analysis FIN 200 Week 4 DQ 1 & DQ 2 FIN 200 Week 5 CheckPoint Long-Term and Short-Term Financin...

  5. Unpredictable chronic stress decreases inhibitory avoidance learning in Tuebingen long-fin zebrafish: stronger effects in the resting phase than in the active phase.

    Manuel, Remy; Gorissen, Marnix; Zethof, Jan; Ebbesson, Lars O E; van de Vis, Hans; Flik, Gert; van den Bos, Ruud

    2014-11-01

    Zebrafish (Danio rerio Hamilton) are increasingly used as a model to study the effects of chronic stress on brain and behaviour. In rodents, unpredictable chronic stress (UCS) has a stronger effect on physiology and behaviour during the active phase than during the resting phase. Here, we applied UCS during the daytime (active phase) for 7 and 14 days or during the night-time (resting phase) for 7 nights in an in-house-reared Tuebingen long-fin (TLF) zebrafish strain. Following UCS, inhibitory avoidance learning was assessed using a 3 day protocol where fish learn to avoid swimming from a white to a black compartment where they will receive a 3 V shock. Latencies of entering the black compartment were recorded before training (day 1; first shock) and after training on day 2 (second shock) and day 3 (no shock, tissue sampling). Fish whole-body cortisol content and expression levels of genes related to stress, fear and anxiety in the telencephalon were quantified. Following 14 days of UCS during the day, inhibitory avoidance learning decreased (lower latencies on days 2 and 3); minor effects were found following 7 days of UCS. Following 7 nights of UCS, inhibitory avoidance learning decreased (lower latency on day 3). Whole-body cortisol levels showed a steady increase compared with controls (100%) from 7 days of UCS (139%), to 14 days of UCS (174%) to 7 nights of UCS (231%), suggestive of an increasing stress load. Only in the 7 nights of UCS group did expression levels of corticoid receptor genes (mr, grα, grβ) and of bdnf increase. These changes are discussed as adaptive mechanisms to maintain neuronal integrity and prevent overload, and as being indicative of a state of high stress load. Overall, our data suggest that stressors during the resting phase have a stronger impact than during the active phase. Our data warrant further studies on the effect of UCS on stress axis-related genes, especially grβ; in mammals this receptor has been implicated in

  6. Toward quantum FinFET

    Wang, Zhiming

    2013-01-01

    This book reviews a range of quantum phenomena in novel nanoscale transistors called FinFETs, including quantized conductance of 1D transport, single electron effect, tunneling transport, etc. The goal is to create a fundamental bridge between quantum FinFET and nanotechnology to stimulate readers' interest in developing new types of semiconductor technology. Although the rapid development of micro-nano fabrication is driving the MOSFET downscaling trend that is evolving from planar channel to nonplanar FinFET, silicon-based CMOS technology is expected to face fundamental limits in the near future. Therefore, new types of nanoscale devices are being investigated aggressively to take advantage of the quantum effect in carrier transport. The quantum confinement effect of FinFET at room temperatures was reported following the breakthrough to sub-10nm scale technology in silicon nanowires. With chapters written by leading scientists throughout the world, Toward Quantum FinFET provides a comprehensive introductio...

  7. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    John S. Palmisano

    2012-01-01

    Full Text Available A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD and experimental results are presented.

  8. Synchronized swimming: coordination of pelvic and pectoral fins during augmented punting by the freshwater stingray Potamotrygon orbignyi.

    Macesic, Laura J; Mulvaney, Dana; Blevins, Erin L

    2013-06-01

    Benthic animals live at the juncture of fluid and solid environments, an interface that shapes many aspects of their behavior, including their means of locomotion. Aquatic walking and similar substrate-dependent forms of underwater propulsion have evolved multiple times in benthic invertebrate and vertebrate taxa, including batoid elasmobranchs. Skates (Rajidae) use the pelvic fins to punt across the substrate, keeping the pectoral fin disc still. Other batoids combine pelvic fin motions with pectoral fin undulation in augmented punting, but the coordination of these two modes has not been described. In this study of an augmented punter, the freshwater stingray Potamotrygon orbignyi, we demonstrate the synchrony of pelvic and pectoral fin cycles. The punt begins as the pelvic fins, held in an anterior position, are planted into the substrate and used to push the body forward. Meanwhile, a wave of pectoral fin undulation begins, increasing to maximum height just before the cycle's halfway point, when the pelvic fins reach their furthest posterior extension. The pectoral fin wave subsides as the pelvic fins return to their starting position for subsequent punts. Despite definitive links between pectoral and pelvic fin activity, we find no significant relationship between pectoral fin kinematics (frequency, wave height, and wave speed) and punt performance. However, slip calculations indicate that pectoral undulation can produce thrust and augment punting. Pelvic fin kinematics (frequency and duty factor) have significant effects, suggesting that while both sets of fins contribute to thrust generation, the pelvic fins likely determine punt performance. PMID:23477972

  9. Bulk FinFETs with body spacers for improving fin height variation

    Wei, Xing; Zhu, Huilong; Zhang, Yanbo; Zhao, Chao

    2016-08-01

    A novel FinFET structure with body spacers in sub fin (BSSF) is proposed to improve the fin height variation produced in the manufacturing processes. Device simulation results are presented to show the electrical variations improvement. The effective fin height (Heff) of FinFETs with BSSF is well controlled because it only depends on the silicon epi layer thickness (TSi). Taking advantage of the precisely controlled epitaxy process, Heff uniformity of FinFETs with BSSF is much better than conventional bulk FinFETs. Benefit from the smaller Heff variation, FinFETs with BSSF show much smaller electrical characteristics variation. For n-FinFETs, the Ion variation improves from 33.46% for conventional bulk FinFETs to 8.05% for FinFETs with BSSF. Additionally, manufacturing of FinFETs with BSSF is compatible with that of the state-of-the-art bulk FinFETs, promising for its applications in massive production.

  10. 50 CFR 600.1204 - Shark finning; possession at sea and landing of shark fins.

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shark finning; possession at sea and landing of shark fins. 600.1204 Section 600.1204 Wildlife and Fisheries FISHERY CONSERVATION AND... PROVISIONS Shark Finning § 600.1204 Shark finning; possession at sea and landing of shark fins. (a)(1)...

  11. FIN 515 DEVRY Material-fin515dotcom

    Sandywilliam6

    2015-01-01

    FIN 515 Entire Course (Devry) For more course tutorials visit www.fin515.com   Week 1 Homework Problems and Mini Case Week 2 Homework Assignment; Problems Week 3 Homework Assignment; Problems Week 3 Homework Problems; 5-1, 5-2, 5-6 Week 4 Homework Problems page 297, 371 Week 4 Midterm; Business Valuation and Stock Valuation Week 5 Homework Problem10-8,10-9,11-2,11-3 Week 5 Project Case 11-7-New-Project Analysis Week 6 Homework Problem12...

  12. FIN 515 devry course Tutorial / fin515dotcom

    anil14

    2015-01-01

    FIN 515 Entire Course (Devry) For more course tutorials visit www.fin515.com   Week 1 Homework Problems and Mini Case Week 2 Homework Assignment; Problems Week 3 Homework Assignment; Problems Week 3 Homework Problems; 5-1, 5-2, 5-6 Week 4 Homework Problems page 297, 371 Week 4 Midterm; Business Valuation and Stock Valuation Week 5 Homework Problem10-8,10-9,11-2,11-3 Week 5 Project Case 11-7-New-Project Analysis Week 6 Homework Problem12...

  13. FIN 515 UOP Course Tutorial/TutorialRank

    apj

    2015-01-01

    For more course tutorials visit www.tutorialrank.com Tutorial Purchased: 4 Times, Rating: A+     FIN 515 Week 1-7 All Discussion Questions (DEVRY) FIN 515 Week 1 Homework assignments (DEVRY) FIN 515 Week 2 Homework Assignment (DEVRY) FIN 515 Week 3 Homework Assignment (DEVRY) FIN 515 Week 4 Homework Assignment (DEVRY) FIN 515 Week 4 Midterm Exam (DEVRY) FIN 515 Week 5 Homework Assignment (DEVRY) FIN 515 Week 5 Project (DEVRY) FIN 5...

  14. Ice nucleating particles measured during the laboratory and field intercomparisons FIN-2 and FIN-3 by the diffusion chamber FRIDGE

    Weber, Daniel; Schrod, Jann; Curtius, Joachim; Haunold, Werner; Thomson, Erik; Bingemer, Heinz

    2016-04-01

    The measurement of atmospheric ice nucleating particles (INP) is still challenging. In the absence of easily applicable INP standards the intercomparison of different methods during collaborative laboratory and field workshops is a valuable tool that can shine light on the performance of individual methods for the measurement of INP [1]. FIN-2 was conducted in March 2015 at the AIDA facility in Karlsruhe as an intercomparison of mobile instruments for measuring INP [2]. FIN-3 was a field campaign at the Desert Research Institutes Storm Peak Laboratory in Colorado in September 2015 [3]. The FRankfurt Ice nucleation Deposition freezinG Experiment (FRIDGE) participated in both experiments. FRIDGE measures ice nucleating particles by electrostatic precipitation of aerosol particles onto Si-wafers in a collection unit, followed by activation, growth, and optical detection of ice crystals on the substrate in an isostatic diffusion chamber [4,5]. We will present and discuss results of our measurements of deposition/condensation INP and of immersion INP with FRIDGE during FIN-2 and FIN-3. Acknowledgements: The valuable contributions of the FIN organizers and their institutions, and of the FIN Workshop Science team are gratefully acknowledged. Our work was supported by Deutsche Forschungsgemeinschaft (DFG) under the Research Unit FOR 1525 (INUIT) and the EU FP7-ENV- 2013 BACCHUS project under Grant Agreement 603445.

  15. A biorobotic model of the sunfish pectoral fin for investigations of fin sensorimotor control

    Phelan, Chris; Tangorra, James [Department of Mechanical Engineering, Drexel University, Philadelphia, PA 19104 (United States); Lauder, George [Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138 (United States); Hale, Melina, E-mail: tangorra@coe.drexel.ed [Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637 (United States)

    2010-09-15

    A comprehensive understanding of the control of flexible fins is fundamental to engineering underwater vehicles that perform like fish, since it is the fins that produce forces which control the fish's motion. However, little is known about the fin's sensory system or about how fish use sensory information to modulate the fin and to control propulsive forces. As part of a research program that involves neuromechanical and behavioral studies of the sunfish pectoral fin, a biorobotic model of the pectoral fin and of the fin's sensorimotor system was developed and used to investigate relationships between sensory information, fin ray motions and propulsive forces. This robotic fin is able to generate the motions and forces of the biological fin during steady swimming and turn maneuvers, and is instrumented with a relatively small set of sensors that represent the biological lateral line and receptors hypothesized to exist intrinsic to the pectoral fin. Results support the idea that fin ray curvature, and the pressure in the flow along the wall that represents the fish body, capture time-varying characteristics of the magnitude and direction of the force created throughout a fin beat. However, none of the sensor modalities alone are sufficient to predict the propulsive force. Knowledge of the time-varying force vector with sufficient detail for the closed-loop control of fin ray motion will result from the integration of characteristics of many sensor modalities.

  16. A biorobotic model of the sunfish pectoral fin for investigations of fin sensorimotor control

    A comprehensive understanding of the control of flexible fins is fundamental to engineering underwater vehicles that perform like fish, since it is the fins that produce forces which control the fish's motion. However, little is known about the fin's sensory system or about how fish use sensory information to modulate the fin and to control propulsive forces. As part of a research program that involves neuromechanical and behavioral studies of the sunfish pectoral fin, a biorobotic model of the pectoral fin and of the fin's sensorimotor system was developed and used to investigate relationships between sensory information, fin ray motions and propulsive forces. This robotic fin is able to generate the motions and forces of the biological fin during steady swimming and turn maneuvers, and is instrumented with a relatively small set of sensors that represent the biological lateral line and receptors hypothesized to exist intrinsic to the pectoral fin. Results support the idea that fin ray curvature, and the pressure in the flow along the wall that represents the fish body, capture time-varying characteristics of the magnitude and direction of the force created throughout a fin beat. However, none of the sensor modalities alone are sufficient to predict the propulsive force. Knowledge of the time-varying force vector with sufficient detail for the closed-loop control of fin ray motion will result from the integration of characteristics of many sensor modalities.

  17. Experimental investigation of self heating effect (SHE) in multiple-fin SOI FinFETs

    In this work, the self-heating effect (SHE) on metal gate multiple-fin SOI FinFETs is studied by adopting the ac conductance technique to extract the thermal resistance and temperature rise in both n-channel and p-channel SOI FinFETs with various geometry parameters. It is shown that the SHE degrades by over 10% of the saturation output current in the n-channel and by over 7% in the p-channel. The extracted thermal resistances Rth increase with the scaled down gate length, reducing the number of fin and shrinking the fin width. The temperature rise caused by the SHE increases with the scaled down gate length, increasing the number of fin and shrinking the fin width under the saturated operation condition. Additionally, due to a larger power density in the n-channel SOI FinFETs under the same bias condition, the temperature in the n-channel FinFETs is higher than that in the p-channel FinFETs. Because the Si thermal conductivity decreases as the temperature increases, Rth is larger in the n-channel FinFETs than in the p-channel FinFETs. Therefore, tradeoffs have to be made between the thermal properties and the device’s electrical performance by careful design optimizations of SOI FinFETs. (paper)

  18. High Fin Width Mosfet Using Gaa Structure

    S.L.Tripathi; Ramanuj Mishra; R. A. Mishra

    2012-01-01

    This paper describes the design and optimization of gate-all-around (GAA) MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior sub threshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the ...

  19. High Fin Width Mosfet Using Gaa Structure

    S.L.Tripathi

    2012-11-01

    Full Text Available This paper describes the design and optimization of gate-all-around (GAA MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior subthreshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the simulations are performed on 3-D TCAD device simulator.

  20. High Fin Width Mosfet Using Gaa Structure

    S.L.Tripathi

    2012-10-01

    Full Text Available This paper describes the design and optimization of gate-all-around (GAA MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior sub threshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the simulations are performed on 3-D TCAD device simulator.

  1. Simulation of Grid-Fin Control Surfaces

    Aftosmis, Michael J.

    2011-01-01

    Conference poster using previously disclosed techniques and methods (see ARC 16210 & 16212). We present simulations of grid-fin control surfaces to demonstrate geometric complexity and numerical robustness. These results have relevance to high-performance computing and performance of grid-fin-based control systems.

  2. Plastic Guidance Fins for Long Rod Projectiles .

    Mark L. Bundy

    1997-10-01

    Full Text Available Projectile tail fins on long rod kinetic energy (KE penetrators serve the same purpose as fletchings (feathers on an arrow, namely, they help align the projectile axis with its velocity vector. This reduces the projectile's yaw and hence reduces its aerodynamic drag. In addition, a low yaw angle at target impact helps to maximise the projectile's target penetration. It is typical for projectiles to exit the gun muzzle and enter free flight at some ndn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create a stabilising torque about the projectile's centre of gravity (CG. This torque can be increased by making the fin material lighter. Most conventional long rod penetrators fired from high performance guns have tail fins made from aluminium. However, aluminium can undergo catastrophic oxidation (rapid burning in-bore. Coating aluminium with Al/sub 2/O/sub 3/ {hardcoat prevents ignition of the substrate, provided solid propellant grain impacts do not chip the brittle hardcoat off the surface. Plastic is lighter than aluminium and less exothermic when oxidized. Therefore, other factors aside, it is conceivable that plastic fins could increase projectile stability while incurring less thermal erosion than aluminium. However, thermal loads are not the only concern when considering plastic as an alternative tail fin material. The mechanical strength of plastic is also a critical factor. This paper discusses some of the successes and failures of plastic fins, at least relatively thin fins, for use as KE stabilisers.

  3. Comparative performance of rippled fin plate fin and tube heat exchangers

    Continuous rippled fins are preferred to interrupted fins in applications where fouling by fibrous matter or insects is a problem. The performance characteristic of three rippled fin heat exchangers have been measured in a thermal wind tunnel. The results of these measurements are reported and comparisons are made wtih published data on similar surfaces. The performance evaluation criteria used as the basis for the comparisons were those recommened by Shah (1978). The tested rippled fin surfaces were found to have a higher performance than a similar surface reported in Kay and London (1984). The heat transfer enhancement was found to be dependent upon the profile of the fin

  4. A comparison of two formulations of the fin efficiency for straight fins

    Ebrahim Momoniat

    2012-01-01

    A formulation of the fin efficiency based on Newton's law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base.The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known,whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known.This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined.The second formulation of the fin efficiency is exact when the first integrals can be determined.

  5. FIN 415 UOP Course Tutorial/TutorialRank

    apj

    2015-01-01

    For more course tutorials visit www.tutorialrank.com Tutorial Purchased: 6 Times, Rating: A+   FIN 415 Week 1 Individual Assignment Risk Management Overview Paper FIN 415 Week 2 Team Assignment Risk Management Identification and Assessment Paper FIN 415 Week 3 Individual Assignment Risk Management Techniques Paper FIN 415 Week 3 Individual Assignment Risk Management Problem, Set I FIN 415 Week 3 Team Assignment Risk Measurement Summary FIN 415 Week 4 I...

  6. The Cx43-like connexin protein Cx40.8 is differentially localized during fin ontogeny and fin regeneration.

    Sarah V Gerhart

    Full Text Available Connexins (Cx are the subunits of gap junctions, membraneous protein channels that permit the exchange of small molecules between adjacent cells. Cx43 is required for cell proliferation in the zebrafish caudal fin. Previously, we found that a Cx43-like connexin, cx40.8, is co-expressed with cx43 in the population of proliferating cells during fin regeneration. Here we demonstrate that Cx40.8 exhibits novel differential subcellular localization in vivo, depending on the growth status of the fin. During fin ontogeny, Cx40.8 is found at the plasma membrane, but Cx40.8 is retained in the Golgi apparatus during regeneration. We next identified a 30 amino acid domain of Cx40.8 responsible for its dynamic localization. One possible explanation for the differential localization is that Cx40.8 contributes to the regulation of Cx43 in vivo, perhaps modifying channel activity during ontogenetic growth. However, we find that the voltage-gating properties of Cx40.8 are similar to Cx43. Together our findings reveal that Cx40.8 exhibits differential subcellular localization in vivo, dependent on a discrete domain in its carboxy terminus. We suggest that the dynamic localization of Cx40.8 differentially influences Cx43-dependent cell proliferation during ontogeny and regeneration.

  7. Fin shape thermal optimization using Bejan's constuctal theory

    Lorenzini, Giulio

    2011-01-01

    The book contains research results obtained by applying Bejan's Constructal Theory to the study and therefore the optimization of fins, focusing on T-shaped and Y-shaped ones. Heat transfer from finned surfaces is an example of combined heat transfer natural or forced convection on the external parts of the fin, and conducting along the fin. Fin's heat exchange is rather complex, because of variation of both temperature along the fin and convective heat transfer coefficient. Furthermore possible presence of more fins invested by the same fluid flow has to be considered.Classical fin theory tri

  8. Fin1-PP1 Helps Clear Spindle Assembly Checkpoint Protein Bub1 from Kinetochores in Anaphase.

    Bokros, Michael; Gravenmier, Curtis; Jin, Fengzhi; Richmond, Daniel; Wang, Yanchang

    2016-02-01

    The spindle assembly checkpoint (SAC) monitors chromosome attachment defects, and the assembly of SAC proteins at kinetochores is essential for its activation, but the SAC disassembly process remains unknown. We found that deletion of a 14-3-3 protein, Bmh1, or hyperactivation of Cdc14 early anaphase release (FEAR) allows premature SAC silencing in budding yeast, which depends on a kinetochore protein Fin1 that forms a complex with protein phosphatase PP1. Previous works suggest that FEAR-dependent Fin1 dephosphorylation promotes Bmh1-Fin1 dissociation, which enables kinetochore recruitment of Fin1-PP1. We found persistent kinetochore association of SAC protein Bub1 in fin1Δ mutants after anaphase entry. Therefore, we revealed a mechanism that clears SAC proteins from kinetochores. After anaphase entry, FEAR activation promotes kinetochore enrichment of Fin1-PP1, resulting in SAC disassembly at kinetochores. This mechanism is required for efficient SAC silencing after SAC is challenged, and untimely Fin1-kinetochore association causes premature SAC silencing and chromosome missegregation. PMID:26832405

  9. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    Subodh Bahirat,; P. V. Joshi

    2014-01-01

    ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT ...

  10. Studi Analitik dan Numerik Perpindahan Panas pada Fin Trapesium (Studi Kasus pada Finned Tube Heat Exchanger

    Ahmad Zaini

    2013-09-01

    Full Text Available Penambahan fin pada pipa penukar kalor merupakan suatu upaya memperbesar perpindahan kalor konduksi dan konveksi, dengan cara memperluas bidang geometri. Pada penelitian ini dianalisa secara analitik dan numerik perpindahan kalor pada fin dengan profil longitudinal tidak seragam atau berubah terhadap jarak dari dasar fin, dengan memvariasikan ketebalan ujung fin. Hasil dari kedua studi ini tidak jauh berbeda, pada keduanya menjelaskan bahwa fin dengan ketebalan ujung 0,9 mm (fin trapesium terbalik paling baik dari 5 variasi lainnya; serta perubahan temperatur paling besar terjadi pada sepertiga pertama dari panjang  fin, ini artinya pelepasan kalor terbesar terjadi pada daerah tersebut. Perbedaannya adalah pada persentase penurunan temperatur sepanjang  fin terhadap temperatur dasar fin, untuk ketebalan 0,9 mm pada studi analitik sebesar 91,92% dan pada studi numerik sebesar 91,78%. Hal ini berarti metode penyelesaian persamaan diferensial orde 2 dengan koefisien variabel dengan cara pembedahan koefisien variabel pada ODE, sudah benar dan valid. Namun bila ditinjau dari waktu yang diperlukan untuk komputasinya, studi analitik membutuhkan waktu lebih lama. Waktu yang diperlukan dalam komputasinya tergantung dari fungsi koefisien variabel.

  11. Methylmercury in dried shark fins and shark fin soup from American restaurants.

    Nalluri, Deepthi; Baumann, Zofia; Abercrombie, Debra L; Chapman, Demian D; Hammerschmidt, Chad R; Fisher, Nicholas S

    2014-10-15

    Consumption of meat from large predatory sharks exposes human consumers to high levels of toxic monomethylmercury (MMHg). There also have been claims that shark fins, and hence the Asian delicacy shark fin soup, contain harmful levels of neurotoxic chemicals in combination with MMHg, although concentrations of MMHg in shark fins are unknown. We measured MMHg in dried, unprocessed fins (n=50) of 13 shark species that occur in the international trade of dried shark fins as well as 50 samples of shark fin soup prepared by restaurants from around the United States. Concentrations of MMHg in fins ranged from 9 to 1720 ng/g dry wt. MMHg in shark fin soup ranged from fins and soup from large, high trophic level sharks such as hammerheads (Sphyrna spp.). Consumption of a 240 mL bowl of shark fin soup containing the average concentration of MMHg (4.6 ng/mL) would result in a dose of 1.1 μg MMHg, which is 16% of the U.S. EPA's reference dose (0.1 μg MMHg per 1 kg per day in adults) of 7.4 μg per day for a 74 kg person. If consumed, the soup containing the highest measured MMHg concentration would exceed the reference dose by 17%. While shark fin soup represents a potentially important source of MMHg to human consumers, other seafood products, particularly the flesh of apex marine predators, contain much higher MMHg concentrations and can result in substantially greater exposures of this contaminant for people. PMID:24835340

  12. A Biologically Derived Pectoral Fin for Yaw Turn Manoeuvres

    Jonah R. Gottlieb

    2010-01-01

    Full Text Available A bio-robotic fin has been developed that models the pectoral fin of the bluegill sunfish as the fish turned to avoid an obstacle. This work involved biological studies of the sunfish fin, the development of kinematic models of the motions of the fin's rays, CFD based predictions of the 3D forces and flows created by the fin, and the implementation of simplified models of the fin's kinematics and mechanical properties in a physical model. The resulting robotic fin produced the forces and flows that drove the manoeuvre and had a sufficiently high number of degrees of freedom to create a variety of non-biologically derived motions. The results indicate that for robotic fins to produce a level of performance on par with biological fins, both the kinematics and the mechanical properties of the biological fin must be modelled well.

  13. THERMAL ANALYSIS OF CPU WITH COMPOSITE PIN FIN HEAT SINKS

    Mohan, R; Dr.P.Govindarajan

    2010-01-01

    This paper describes about pin fin and slot parallel plate heat sinks with copper and carbon carbon composite(CCC) base plate material mounted on CPU’s. The parameters such as fin geometry, base plate material, base plate thickness, number of fins, fin thickness are considered and primarily in this paper fin geometry, base platethicknesses, base plate materials are optimized for improving the thermal performance of a heat sink in the next generation. In this research work, the thermal model o...

  14. Heat transfer through constant section fins at hear transfer coefficient, changed along the fin height

    Paper presents an analytical solution of the problem to determine the efficiency coefficient of a constant section fin at heat transfer coefficient changing along fin height. It is determined, that the commonly applied assumption about the constancy of a convectional coefficient of heat emission when calculating the efficiency of a fin based on the value of the reduced coefficient of heat emission results in the error reaching 15%. It is shown that to reduce it up to 2-3% when calculating the efficiency coefficient of a fin one should have the experimental values of both the reduced coefficient of heat emission and the convectional coefficient of heat emission at a surface supporting the fins

  15. Comparative Study of Effect of Fin Arrangement on Propulsion Performance of Bio-inspired Underwater Vehicles with Multiple SMA Fins

    Jian-hui He

    2015-09-01

    Full Text Available A biologically inspired underwater vehicle (BIUV was built using multiple lightweight bio inspired shape memory alloy (SMA fins. An unsteady 3D computational fluid dynamics (CFD method using an unstructured, grid-based, and unsteady Navier-Stokes solver with automatic adaptive re-meshing was adopted to compute unsteady flow. The hydrodynamics of multiple fins at a certain Reynolds number (Re = Uc/ν, where U is the upstream flow velocity, c is the chord length, and ν is the kinematic viscosity was studied and simulated using CFD to estimate hydrodynamic forces and characterize flow and vortex patterns created by the fins. Two common arrangements of multiple fins on the BIUV were considered: a posterior fin that is parallel to the anterior fins (case 1 and a posterior fin that is perpendicular to the anterior fins (case 2. First, the influence of the distance between two anterior undulating fins on the propulsion performance of both arrangements of multiple fins on the BIUV was investigated. The effect of the distance between the anterior undulating fins and the posterior oscillating fin was also analysed. The length of the posterior oscillating fin was varied and the fin surface area was held constant (24 mm2 to illustrate the influence of this parameter. Finally, the effect of frequency, amplitude, and wave number of anterior undulating fins on the non-dimensional drag coefficient of the posterior oscillating fin was investigated. Based on the flow structures, the reasons for the different performances of the BIUV are discussed. BIUV performances largely depend on the arrangements of multiple fins and the gap between the fins. Dimension and kinematic parameters also affect the performance of the BIUV. The results provide a physical insight into the understanding of fin interaction in fish or BIUVs that are propelled by multiple fins.

  16. Performance of tubes-and plate fins heat exchangers

    By means of a two-dimensional analysis performance, and using local heat transfer coefficients, the plate fin temperature distribution, the air bulk temperature along the stream path and the fin efficiency can be obtained, for several Reynolds numbers and fin materials. Herein are also presented the average heat transfer coefficients for isothermal plate fins, referring to heat exchangers with central-tube and rear-tube row and to two-row tubes heat exchangers configurations. It is possible to obtain the real tax or the real area of heat transfer, using the average hea transfer coefficients for isothermal plate fins and the fin efficiency. (Author)

  17. Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors

    Young, Chadwin D., E-mail: chadwin.young@utdallas.edu; Wang, Zhe [Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080 (United States); Neugroschel, Arnost [Department of Electrical and Computer Enginering, University of Florida, Gainesville, Florida 32611 (United States); Majumdar, Kausik; Matthews, Ken; Hobbs, Chris [SEMATECH, Albany, New York 12203 (United States)

    2015-01-21

    The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.

  18. Successful euthanasia of a juvenile fin whale.

    Daoust, P Y; Ortenburger, A I

    2001-01-01

    A stranded juvenile fin whale was successfully euthanized with an intravenous injection of sedative and cardioplegic drugs. Veterinarians may face a number of serious difficulties if called to perform this task, and advance preparation is required for successful euthanasia of these animals.

  19. Room to high temperature measurements of flexible SOI FinFETs with sub-20-nm fins

    Diab, Amer El Hajj

    2014-12-01

    We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of temperature variation on drain current, gate leakage current, and transconductance. Variation of extracted parameters, such as low-field mobility, subthreshold swing, threshold voltage, and ON-OFF current characteristics, is reported too. Direct comparison is made to a rigid version of the SOI FinFETs. The mobility degradation with temperature is mainly caused by phonon scattering mechanism. The overall excellent devices performance at high temperature after release is outlined proving the suitability of truly high-performance flexible inorganic electronics with such advanced architecture.

  20. Curvature-induced stiffening of a fish fin

    Nguyen, Khoi; Bandi, Mahesh M; Venkadesan, Madhusudhan; Mandre, Shreyas

    2016-01-01

    Fish behaviour and its ecological niche require modulation of its fin stiffness. Using mathematical analyses of rayed fish fins, we show that curvature transverse to the rays is central to fin stiffness. We model the fin as rays with anisotropic bending that are connected by an elastic membrane. For fins with transverse curvature, external loads that bend the rays also splay them apart, which stretches the membrane. This coupling, between ray bending and membrane stretching, underlies the curvature-induced stiffness. A fin that appears flat may still exhibit bending-stretching coupling if the principal bending axes of adjacent rays are misaligned by virtue of intrinsic geometry, i.e. morphologically flat yet functionally curved. Analysis of the pectoral fin of a mackerel shows such functional curvature. Furthermore, as identified by our analyses, the mackerel's fin morphology endows it with the potential to modulate stiffness over a wide range.

  1. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    Subodh Bahirat,

    2014-08-01

    Full Text Available ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT was used in the fin-tube heat exchanger. The fluid flow and heat transfer are simulated and result compared for both laminar and turbulent flow models k-epsilon and SST k-omega, with steady state solvers to calculate heat transfer, flow velocity and temperature fields of variable inclined fin angles (Ɵ = 00 ,100 , 200 , 300 , 400 ,500 . Model is validate by comparing the simulated value of velocity, temperature and colburn factor with experimental and numerical results investigated by WANG [1] and GHORI KIRAR [10]. Reasonable agreement is found between the simulations and other results, and the ANSYS Fluent software is sufficient for simulating the flow fields in tube fin heat exchanger.

  2. Uniform fin sizes versus uniform fin root temperatures for unsymmetrically obstructed solar probe RTGs

    The Solar Probe will approach the sun within four solar radii or 0.02 AU. Because of that proximity, the spacecraft must be protected by a thermal shield. The protected umbra is a cone of 4 m diameter and 7.5 m height, and all temperature-sensitive flight components must fit within the cone. Therefore, the radioisotope thermal generators which power the Solar Probe cannot be separated from each other and from other payload components by deploying them on long booms, as was done on previous missions. Instead, the RTGs must be located near and thermally isolated from the spacecraft's payload. As a result, only about half of each RTGs circumference has a direct view of space. The other half is cooled indirectly, by means of a semi-cylindrical reflector. For a standard RTG design with uniform radiator fins, the unsymmetrical reflectors result in significant circumferential variations in the thermocouples' cold-junction temperatures, voltages, and currents. This can be avoided by varying the dimensions of the radiator fins, so as to produce a uniform set of fin root temperatures. The paper compares the performance of such variable-fin RTGs with that of uniform-fin RTGs. It derives the fin dimensions required for circumferential isothermicity, identifies a design that maximizes the RTG's specific power, and proves the practicality of that design option

  3. Research on the Pin Fin Efficiency and Structure

    Fan Bailin; Huang Ganghan; Xu Long; Wang Yanjun; Zhang Pei

    2013-01-01

    The performance of pin fin heat sink can be to measure through the temperature field. The temperature field and efficiency of the Pin Fin were analyzed, Pin fin efficiency curve was drowned also the distribution of the temperature field along the length of the pin fin curve was drawn. Thermal resistance was composed by thermal resistance of Aluminum substrate、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through t...

  4. Numerical Analysis and Optimization of Engine Cylinder Fins of Varying

    Saravanan

    2014-01-01

    The main aim of the project is to analyze the thermal properties by varying geometry, material and thickness of cylinder fins. Parametric models of cylinder with fins have been developed to predict the transient thermal behavior. The models are created by varying the geometry, rectangular, circular and curved shaped fins and also by varying thickness of the fins. The 3D modeling software used is Pro/Engineer.The analysis is done using ANSYS. Presently Material used for manufac...

  5. Three-dimensional natural convection in finned cubical enclosures

    Three-dimensional natural convection of air in a cubical enclosure with a fin on the hot wall is numerically investigated for Rayleigh numbers of 103-106. The fin, with a thickness of 1/10 of the cavity side, is placed horizontally on the hot wall. The solid to fluid thermal conductivity ratio (R k) and the fin width are varied. Because the fin is shorter than the cavity side, the cold flow sweeps the lower fin face and the hot wall at the clearances between the fin sides and the lateral walls, where high vertical velocities are reached. The fin inhibits the frontal and lateral access of fluid to the upper fin face, especially at low Rayleigh numbers. Low values of R k cause heat transfer reductions. The contribution of the fin faces increases at high R k causing heat transfer enhancements above 20%, which exceed the ones obtained in most two-dimensional studies. In the range of Ra from 105 to 106, maximum heat transfer rates are found for dimensionless fin widths of 0.6 and 0.8 respectively. It is concluded that for 105 ≤ Ra ≤ 106 a fin of partial width is more effective in promoting heat transfer than a fin of full width

  6. Enhanced hydrodynamic performance of flexible fins using macro fiber composite actuators

    Recent studies on the role of body flexibility in propulsion suggest that fish have the ability to control the shape or modulate the stiffness of the fins for optimized performance. Inspired by nature’s ability to modulate stiffness and shape for different operating conditions, this paper investigates active control of flapping foils for thrust tailoring using Macro Fiber Composites (MFCs). A coupled piezohydroelastic model has been developed to predict the propulsive performance of an actively deforming fin. The effect of important parameters such as oscillation frequency, flexibility of the fin, applied voltage and the phase difference between applied voltage and heaving on propulsive performance are studied and reported. It is observed that distributed actuation along fin produces maximum performance through proper selection of the phase difference between heaving and voltage. The optimal phase for lower values of fin stiffness is approximately 90° and it approaches 0° for higher stiffness values. Experiments performed to determine the effect of active control using MFCs validate the theoretical results. (paper)

  7. Composite hydrophilic coating for conditioner aluminum fins

    1999-01-01

    To solve the so-called "white rust" and 'water bridge" problems of the aluminum fins for heat exchanger of automobile air conditioner, aimed at nationalizing the art of hydrophilic coating technology, the choice of coating forming and curing materials was investigated. By measuring the water contact angle, SEM surface scanning and ingredients analysis of the coating, optimal parameters and composition are acquired. The coating forming mechanisms of the composition was also expatiated. The coating obtained has good hydrophilic and other properties.

  8. NUMERICAL AND EXPERIMENTAL STUDIES OF INFLUENCE OF THE CAUDAL FIN SHAPE ON THE PROPULSION PERFORMANCE OF A FLAPPING CAUDAL FIN

    ZHANG Xi; SU Yu-min; WANG Zhao-li

    2011-01-01

    This article presents a comprehensive study of the effects of the caudal fin shape on the propulsion performance of a eandal fin in harmonic heaving and pitching.A numerical simulation based on an unsteady panel method was carried out to analyze the hydrodynamic performance of flapping caudal fins of three shapes (the whale caudal fin with the largest projected area, the dolphin caudal fin with the median projected area, and the tuna caudal fin with the smallest projected area).Then, a series of hydrodynamic experiments for three caudal fin shapes were performed.Both computational and experimental results indicate that the tuna caudal fin produces the highest efficiency.However the mean thrust coefficient of the tuna caudal fin is the smallest.It is found that although the mean thrust coefficient for the tuna caudal fin is not large, the input power of the tuna caudal fin is also quite small.So the tuna caudal fin achieves a high efficiency.

  9. Study on Thermo-Conductive Plastic Finned Tube Radiators

    1997-01-01

    This paper discusses thermo-conductive plastic finned tube radiators used in water saving type power stations.First,the development of thermo-conductive plastics is introduced.Second,in order to determine the rational geometric dimensions of thermo-conductive plastic finned tubes,an objective function which takes the minimum volume of the consumed material for making finned tubes as an object is introduced.On the basis of the function,the economy comparison between thermo-conductive plastic finned tubes and metal finned tubes is conducted.

  10. An IPMC-enabled bio-inspired bending/twisting fin for underwater applications

    This paper discusses the design, fabrication, and characterization of an ionic polymer–metal composite (IPMC) actuator-based bio-inspired active fin capable of bending and twisting motion. It is pointed out that IPMC strip actuators are used in the simple cantilever configuration to create simple bending (flapping-like) motion for propulsion in underwater autonomous systems. However, the resulting motion is a simple 1D bending and performance is rather limited. To enable more complex deformation, such as the flapping (pitch and heaving) motion of real pectoral and caudal fish fins, a new approach which involves molding or integrating IPMC actuators into a soft boot material to create an active control surface (called a ‘fin’) is presented. The fin can be used to realize complex deformation depending on the orientation and placement of the actuators. In contrast to previously created IPMCs with patterned electrodes for the same purpose, the proposed design avoids (1) the more expensive process of electroless plating platinum all throughout the surface of the actuator and (2) the need for specially patterning the electrodes. Therefore, standard shaped IPMC actuators such as those with rectangular dimensions with varying thicknesses can be used. One unique advantage of the proposed structural design is that custom shaped fins and control surfaces can be easily created without special materials processing. The molding process is cost effective and does not require functionalizing or ‘activating’ the boot material similar to creating IPMCs. For a prototype fin (90 mm wide × 60 mm long × 1.5 mm thick), the measured maximum tip displacement was approximately 44 mm and the twist angle of the fin exceeded 10°. Lift and drag measurements in water where the prototype fin with an airfoil profile was dragged through water at a velocity of 21 cm s−1 showed that the lift and drag forces can be affected by controlling the IPMCs embedded into the fin structure. These

  11. Studying Fin Whales with Seafloor Seismic Networks

    Wilcock, W. S.; Soule, D. C.; Weirathmueller, M.; Thomson, R.

    2011-12-01

    Baleen whales are found throughout the world's oceans and their welfare captivates the general public. Depending on the species, baleen whales vocalize at frequencies ranging from ~10 Hz to several kilohertz. Passive acoustic studies of whale calls are used to investigate behavior and habitat usage, monitor the recovery of populations from whaling and assess the impacts of anthropogenic sounds. Since airguns are a significant source of sound in the oceans, the research goals of academic seismologists can lead to conflicts with those who advocate for whale conservation while being unwilling to consider the societal benefits of marine geophysical studies. In contrast, studies that monitor earthquakes with ocean bottom seismometers (OBSs) provide an opportunity to enhance studies of baleen whales and improve relationships with environmental advocates. The bandwidth of the typical high-frequency or intermediate-band ocean bottom seismometer overlaps the call frequency of the two largest baleen whale species; blue whales generate sequences of 10- to 20-s-long calls centered at ~16 Hz and fin whales produce long sequences of downswept 1-s-long chirps centered at ~20 Hz. Several studies have demonstrated the potential of OBS networks to monitor calling patterns and determine tracks for fin and blue whales. We will summarize the results from a study to track fin whales near the Endeavour hydrothermal vent fields on the Juan de Fuca Ridge and investigate a potential correlation between the density of whales and enhanced zooplankton found throughout the water column overlying the vent fields. From 2003-2006 an 8-station local seismic network that was designed to monitor hydrothermal earthquakes also recorded ~300,000 fin whale vocalizations, mostly in the fall and winter. Automatic picking and localization techniques that are analogous to those used to analyze earthquakes are employed to determine whale tracks. The tracks are then used to interpret calling patterns in the

  12. An approach to optimal fin diameter based on entropy minimization

    Masoud Asadi

    2013-04-01

    Full Text Available Pin fin geometries provide a large surface area of heat transfer and reduce the thermal resistance of the package. One of the important features of this type of fins is that they often take less space and contribute less to the weight and cost of the product. Pin fin arrays are used widely in many applications such as gas turbine or electronic circuits cooling, where pin fin geometries use due to their low cost of manufacturing and easy installing. In gas turbine application heat transfer from the blade to the coolant air can be increased by installing pin fins. In fact, Pin fin arrays increase heat transfer by increasing the flow turbulence and surface area of the airfoil exposed to the coolant. The overall performance of a heat exchanger with pin-fin typically depends on a number of parameters including the fin diameter, dimensions of the baseplate and pin-fins, thermal joint resistance and location heat sources. These parameters have an impact on the optimal design of a heat exchanger. Fin diameter is a key parameter to determine overall heat exchanger efficiency and entropy generation. In this paper, our objective is introducing an Equation to calculate optimal fin diameter based on minimizing entropy generation.

  13. Investigating the effect of non-similar fins in thermoeconomic optimization of plate fin heat exchanger

    Thermoeconomic optimization of plate fin heat exchanger with similar (SF) and different (DF) or non-similar fin in each side is presented in this work. For this purpose, both heat exchanger effectiveness and total annual cost (TAC) are optimized simultaneously using multi-objective particle swarm optimization algorithm. The above procedure is performed for various mass flow rates in each side. The optimum results reveal that no thermoeconomic improvement is observed in the case of same mass flow rate in each side while both effectiveness and TAC are improved in the case of different mass flow rate. For example, effectiveness and TAC are improved 0.95% and 10.17% respectively, for the DF compared with SF. In fact, the fin configuration should be selected more compact in a side with lower mass flow rate compared with the other side in the thermoeconomic viewpoint. Furthermore, for the thermodynamic optimization viewpoint both SF and DF have the same optimum result while for the economic (or thermoeconomic) optimization viewpoint, the significant decrease in TAC is accessible in the case of DF compared with SF. - Highlights: • Thermoeconomic modeling of compact heat exchanger. • Selection of fin and heat exchanger geometries as nine decision variables. • Applying MOPSO algorithm for multi objective optimization. • Considering the similar and different fin specification in each side. • Investigation of optimum design parameters for various mass flow rates

  14. THERMAL ANALYSIS OF CPU WITH COMPOSITE PIN FIN HEAT SINKS

    R.Mohan

    2010-09-01

    Full Text Available This paper describes about pin fin and slot parallel plate heat sinks with copper and carbon carbon composite(CCC base plate material mounted on CPU’s. The parameters such as fin geometry, base plate material, base plate thickness, number of fins, fin thickness are considered and primarily in this paper fin geometry, base platethicknesses, base plate materials are optimized for improving the thermal performance of a heat sink in the next generation. In this research work, the thermal model of the computer system with various fin geometry heat sink design has been selected and the fluid flow, thermal flow characteristics of heat sinks have been studied. The plate, pin and Elliptical fin geometry heat sinks have been used with base plate to enhance the heat dissipation. In this study a complete computer chassis with different heat sinks are investigated and the performances of the heat sinks are compared.

  15. Influence of Tip Clearance on Forced Convection Heat Transfer of a Finned Plate in a Duct

    Optimizations are required for a proper enhancement of cooling capability. An important phenomenological consideration is to be reveals for a finned plate in a duct. Due to the high friction near the fin region and low friction near the wall region, the forced flow tends to bypass from fin region to wall region. The bypass flow increases the net flow and enhances the heat transfer for a moderate tip clearance which is defined by the distance from the tip of the fin and the wall. Meanwhile for a large tip clearance, most of the flow bypasses and does not contribute the heat transfer and impairs the heat transfer. This study is a preliminary numerical study on the influence of the tip clearance on the heat transfer of the finned plate in a duct. The study aimed at supporting an experimental research exploring the phenomena for a very small tip clearance. Thus material properties and test conditions were chosen to meet the experimental conditions. It investigated the phenomena at Pr of 2,014 and ReS of 58.3. In order to investigate the small tip clearance phenomena, a simple numerical scheme was developed using a commercial CFD code. A case with the same experimental condition was tested using the numerical scheme and the error was about 12%. The results show the clear evidence of the flow bypass from the fin region to wall region, which impair the heat removal capacity of the finned plate in a duct. The study has the relevance with the reactor cavity cooling system performance enhancement activities in the VHTR. The numerical scheme will be tested for narrower and wider tip clearances and find an optimal tip clearance

  16. Influence of Tip Clearance on Forced Convection Heat Transfer of a Finned Plate in a Duct

    Park, Haekyun; Chung, Bumjin [Kyung Hee Univ., Yongin (Korea, Republic of)

    2014-05-15

    Optimizations are required for a proper enhancement of cooling capability. An important phenomenological consideration is to be reveals for a finned plate in a duct. Due to the high friction near the fin region and low friction near the wall region, the forced flow tends to bypass from fin region to wall region. The bypass flow increases the net flow and enhances the heat transfer for a moderate tip clearance which is defined by the distance from the tip of the fin and the wall. Meanwhile for a large tip clearance, most of the flow bypasses and does not contribute the heat transfer and impairs the heat transfer. This study is a preliminary numerical study on the influence of the tip clearance on the heat transfer of the finned plate in a duct. The study aimed at supporting an experimental research exploring the phenomena for a very small tip clearance. Thus material properties and test conditions were chosen to meet the experimental conditions. It investigated the phenomena at Pr of 2,014 and ReS of 58.3. In order to investigate the small tip clearance phenomena, a simple numerical scheme was developed using a commercial CFD code. A case with the same experimental condition was tested using the numerical scheme and the error was about 12%. The results show the clear evidence of the flow bypass from the fin region to wall region, which impair the heat removal capacity of the finned plate in a duct. The study has the relevance with the reactor cavity cooling system performance enhancement activities in the VHTR. The numerical scheme will be tested for narrower and wider tip clearances and find an optimal tip clearance.

  17. Investigation of Fish Caudal Fin Locomotion Using a Bio-inspired Robotic Model

    Ziyu Ren

    2016-05-01

    Full Text Available Due to its advantages of realizing repeatable experiments, collecting data and isolating key factors, the bio-robotic model is becoming increasingly important in the study of biomechanics. The caudal fin of fish has long been understood to be central to propulsion performance, yet its contribution to manoeuverability, especially for homocercal caudal fin, has not been studied in depth. In the research outlined in this paper, we designed and fabricated a robotic caudal fin to mimic the morphology and the three-dimensional (3D locomotion of the tail of the Bluegill Sunfish (Lepomis macrochirus. We applied heave and pitch motions to the robot to model the movement of the caudal peduncle of its biological counterpart. Force measurements and 2D and 3D digital particle image velocimetry were then conducted under different movement patterns and flow speeds. From the force data, we found the addition of the 3D caudal fin locomotion significantly enhanced the lift force magnitude. The phase difference between the caudal fin ray and peduncle motion was a key factor in simultaneously controlling the thrust and lift. The increased flow speed had a negative impact on the generation of lift force. From the average 2D velocity field, we observed that the vortex wake directed water both axially and vertically, and formed a jet like structure with notable wake velocity. The 3D instantaneous velocity field at 0.6 T indicated the 3D motion of the caudal fin may result in asymmetry wake flow patterns relative to the mid-sagittal plane and change the heading direction of the shedding vortexes. Based on these results, we hypothesized that live fish may actively tune the movement between the caudal fin rays and the peduncle to change the wake structure behind the tail and hence obtain different thrust and lift forces, which contributes to its high manoeuvrability.

  18. Performance Evaluation of Plate-Fin-And Tube Heat Exchanger with Wavy Fins- A Review

    Sandip S. Kale

    2014-09-01

    Full Text Available The plate fin-and-tube heat exchangers are widely used in variety of industrial applications, particularly in the heating, air-conditioning and refrigeration, HVAC industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. It is seen that the performance of heat exchangers can be greatly increased with the use of unconventionally shaped flow passages such as plain, perforated offset strip, louvered, wavy, vortex generator and pin. The current study is focused on wavy-fin. The wavy surface can lengthen the path of airflow and cause better airflow mixing. In order to design better heat exchangers and come up with efficient designs, a thorough understanding of the flow of air in these channels is required. Hence this study focuses on the heat transfer and friction characteristics of the air side for wavy fin and tube heat exchanger.

  19. Advances in Understanding the Role of Aerosols on Ice Clouds from the Fifth International Ice Nucleation (FIN) Workshops

    Cziczo, D. J.; Moehler, O.; DeMott, P. J.

    2015-12-01

    The relationship of ambient aerosol particles to the formation of ice-containing clouds is one of the largest uncertainties in understanding climate. This is due to several poorly understood processes including the microphysics of how particles nucleate ice, the number of effective heterogeneous ice nuclei and their atmospheric distribution, the role of anthropogenic activities in producing or changing the behavior of ice forming particles and the interplay between effective heterogeneous ice nuclei and homogeneous ice formation. Our team recently completed a three-part international workshop to improve our understanding of atmospheric ice formation. Termed the Fifth International Ice Nucleation (FIN) Workshops, our motivation was the limited number of measurements and a lack of understanding of how to compare data acquired by different groups. The first activity, termed FIN1, addressed the characterization of ice nucleating particle size, number and chemical composition. FIN2 addressed the determination of ice nucleating particle number density. Groups modeling ice nucleation joined FIN2 to provide insight on measurements critically needed to model atmospheric ice nucleation and to understand the performance of ice chambers. FIN1 and FIN2 took place at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) chamber at the Karlsruhe Institute of Technology. A particular emphasis of FIN1 and FIN2 was the use of 'blind' intercomparisons using a highly characterized, but unknown to the instrument operators, aerosol sample. The third activity, FIN3, took place at the Desert Research Institute's Storm Peak Laboratory (SPL). A high elevation site not subject to local emissions, SPL allowed for a comparison of ice chambers and subsequent analysis of the ice residuals under the challenging conditions of low particle loading, temperature and pressure found in the atmosphere. The presentation focuses on the improvement in understanding how mass spectra from different

  20. Life-long preservation of the regenerative capacity in the fin and heart in zebrafish

    Junji Itou

    2012-06-01

    The zebrafish is a widely used model animal to study the regeneration of organs, such as the fin and heart. Their average lifetime is about 3 years, and recent studies have shown that zebrafish exhibit aging-related degeneration, suggesting the possibility that aging might affect regenerative potential. In order to investigate this possibility, we compared regeneration of the fin and heart after experimental amputation in young (6–12 month old and old (26–36 month old fish. Comparison of recovery rate of the caudal fin, measured every two or three days from one day post amputation until 13 days post amputation, show that fins in young and old fish regenerate at a similar rate. In the heart, myocardium regeneration and cardiomyocyte proliferation occurred similarly in the two groups. Moreover, neo-vascularization, as well as activation of fibroblast growth factor signaling, which is required for neo-vascularization, occurred similarly. The epicardial tissue is a thin layer tissue that covers the heart, and starts to express several genes immediately in response to injury. The expression of epicardial genes, such as wt1b and aldh1a2, in response to heart injury was comparable in two groups. Our results demonstrate that zebrafish preserve a life-long regenerative ability of the caudal fin and heart.

  1. Undulating fins produce off-axis thrust and flow structures.

    Neveln, Izaak D; Bale, Rahul; Bhalla, Amneet Pal Singh; Curet, Oscar M; Patankar, Neelesh A; MacIver, Malcolm A

    2014-01-15

    While wake structures of many forms of swimming and flying are well characterized, the wake generated by a freely swimming undulating fin has not yet been analyzed. These elongated fins allow fish to achieve enhanced agility exemplified by the forward, backward and vertical swimming capabilities of knifefish, and also have potential applications in the design of more maneuverable underwater vehicles. We present the flow structure of an undulating robotic fin model using particle image velocimetry to measure fluid velocity fields in the wake. We supplement the experimental robotic work with high-fidelity computational fluid dynamics, simulating the hydrodynamics of both a virtual fish, whose fin kinematics and fin plus body morphology are measured from a freely swimming knifefish, and a virtual rendering of our robot. Our results indicate that a series of linked vortex tubes is shed off the long edge of the fin as the undulatory wave travels lengthwise along the fin. A jet at an oblique angle to the fin is associated with the successive vortex tubes, propelling the fish forward. The vortex structure bears similarity to the linked vortex ring structure trailing the oscillating caudal fin of a carangiform swimmer, though the vortex rings are distorted because of the undulatory kinematics of the elongated fin. PMID:24072799

  2. Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

    Yong-hua Zhang; Lai-bing Jia; Shi-wu Zhang; Jie Yang; K.H.Low

    2007-01-01

    Biomimetic design employs the principles of nature to solve engineering problems.Such designs which are hoped to be quick,efficient,robust,and versatile,have taken advantage of optimization via natural selection.In the present research.an environment-friendly propulsion system mimicking undulating fins of stingray was built.A non-conventional method was considered to model the flexibility of the fins of stingray.A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin.The driving linkages were used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fins.Owing to the modularity of the design of the mechanical fin,various undulating patterns can be realized.Some qualitative observations,obtained by experiments,predicted that the thrusts produced by the mechanical fin are different among various undulating patterns.To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system.Here,four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics(CFD)method.An unstructured,grid-based,unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles.The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into lift and thrust.The pressure force and friction force were also computed throughout the swimming cycle.Finally,vortex contour maps of these four basic fin undulating patterns were displayed and compared.

  3. Stability Criterion for a Finned Spinning Projectile

    S. D. Naik

    2000-01-01

    Full Text Available The state-of-the-art in gun projectile technology has been used for the aerodynamic stabilisation.This approach is acceptable for guided and controlled rockets but the free-flight rockets suffer fromunacceptable dispersion. Sabot projectiles with both spin and fms developed during the last decadeneed careful analysis. In this study, the second method of Liapunov has been used to develop stability criterion for a projectile to be designed with small fins and is made to spin in the flight. This criterion is useful for the designer.

  4. Optimal design study of cylindrical finned reactor for solar adsorption cooling machine

    Allouache, N. [Univ. des Sciences et de la Technologie Houari Boumediene, Bab Ezzouar (Algeria). Faculte de Genie Mecanique et de Genie des Procedes; Al Mers, A. [Moulay Ismail Univ., Meknes (Morocco). Ecole National Superieure d' Art et Metiers

    2010-07-01

    Solid adsorption cooling machines use medium temperature industrial waste heat together with a renewable energy source, such as solar energy. The adsorption cooling machine consists of an evaporator, a condenser and a reactor containing a solid adsorbent. In this study, a model was developed for thermodynamic performance analysis and optimization of a cylindrical finned solar reactor in an adsorption refrigerator working with activated carbon-ammonia. The heat and mass transfer in the adsorption cooling machine was determined. The model was validated using experimental results. The study investigated the sensitivity of the machine performance versus the geometrical configuration of the reactor. The study showed that for an optimized reactor, a higher fin number significantly reduces the heat losses of the reactor. It was concluded that the solar coefficient of performance (COP) of an optimized reactor can reach 45 per cent when the number of fins varies between 5 and 6. 10 refs., 4 figs.

  5. Thermal Analysis of Fin and Tube Heat Exchanger

    Ms N. B. Rairker

    2014-06-01

    Full Text Available This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed that as the width of fin increases thermal stresses on fin also increases. Likewise for tube, by varying diameter of tube different values of stress are obtained. It is also observed at full valve position maximum thermal stresses are induced on fin as well as tube.

  6. Air cooling effect of fins on a Honda shine bike

    Padhiyar Abhesinh J

    2015-05-01

    Full Text Available The main of aim of this work is to study various researches done in past to improve heat transfer rate of cooling fins by changing cylinder block fin geometry. Low rate of heat transfer through cooling fins is the main problem in this type of cooling. So efficiency of the engine is increase by increase the heat transfer. Examples of direct air cooling in modern automobiles are rare. The most common example is the commercials Automobile bike like a Honda Shine, Bajaj bike, Honda splendor etc. It is conclude about shape try to this fins is more effectively heat transfer in Honda shine bike compare to existing fins. After FEA Analysis it checking on fin whether efficiency of heat transfer increases or not. This work validation with Experimental and Mathematical.

  7. Numerical simulation of heat exchangers elliptical tubes and corrugated fins

    The intensified heat exchangers fins are widely used in the automotive and domestic industry. The low heat transfer coefficients on the air side are the main reason why these fins of heat exchangers need to be intensified. In this paper, the numerical simulation of a wavy fin type is made with elliptical tubes. The dimensions of the fin is in the range of those used in air conditioning equipment. The friction factor and the mass transfer coefficient as a function of the Reynolds number for this type of fin, always within the laminar regime is determined. The numerical model against experimental results published in the literature is validated. In addition the mechanisms that produce intensified heat transfer fin in such occur. (full text)

  8. The role of flexibility on propulsive performance of flapping fins

    Kancharala, Ashok Kumar

    2015-01-01

    The versatility of the fish to adapt to diverse swimming requirements has attracted the attention of researchers in studying bioinspired propulsion for developing efficient underwater robotics. The tail/caudal fin is a major source of thrust generation and is believed that the fish modulates its fin stiffness to optimize the propulsive performance. Inspired by the stiffness modulation of fish fins, the objective of this research is to predict and evaluate the effect of flexibility on propulsi...

  9. Influence of fins on tractor-type podded propulsor performance

    Xie, Xue-Shen; Huang, Sheng

    2009-09-01

    A mathematical model of podded propulsors was established in order to investigate the influence of fins. The hydrodynamic performance of podded propulsors with and without fins was calculated, with interactions between propellers and pods and fins derived by iterative calculation. The differential equation based on velocity potential was adopted and hyperboloidal panels were used to avoid gaps between surface panels. The Newton-Raphson iterative procedure was used on the trailing edge to meet the pressure Kutta condition. The velocity distribution was calculated with the Yanagizawa method to eliminate the singularity caused by use of the numerical differential. Comparisons of the performance of podded propulsors with different fins showed that the thrust of propeller in a podded propulsor with fins is greater. The resistance of the pod is also reduced because of the thrust of the fin. The hydrodynamic performance of a podded propulsor with two fins is found to be best, the performance of a podded propulsor with one fin is not as good as two fins, and the performance of the common type is the worst.

  10. Grid Fin Stabilization of the Orion Launch Abort Vehicle

    Pruzan, Daniel A.; Mendenhall, Michael R.; Rose, William C.; Schuster, David M.

    2011-01-01

    Wind tunnel tests were conducted by Nielsen Engineering & Research (NEAR) and Rose Engineering & Research (REAR) in conjunction with the NASA Engineering & Safety Center (NESC) on a 6%-scale model of the Orion launch abort vehicle (LAV) configured with four grid fins mounted near the base of the vehicle. The objectives of these tests were to 1) quantify LAV stability augmentation provided by the grid fins from subsonic through supersonic Mach numbers, 2) assess the benefits of swept grid fins versus unswept grid fins on the LAV, 3) determine the effects of the LAV abort motors on grid fin aerodynamics, and 4) generate an aerodynamic database for use in the future application of grid fins to small length-to-diameter ratio vehicles similar to the LAV. The tests were conducted in NASA Ames Research Center's 11x11-foot transonic wind tunnel from Mach 0.5 through Mach 1.3 and in their 9x7-foot supersonic wind tunnel from Mach 1.6 through Mach 2.5. Force- and moment-coefficient data were collected for the complete vehicle and for each individual grid fin as a function of angle of attack and sideslip angle. Tests were conducted with both swept and unswept grid fins with the simulated abort motors (cold jets) off and on. The swept grid fins were designed with a 22.5deg aft sweep angle for both the frame and the internal lattice so that the frontal projection of the swept fins was the same as for the unswept fins. Data from these tests indicate that both unswept and swept grid fins provide significant improvements in pitch stability as compared to the baseline vehicle over the Mach number range investigated. The swept fins typically provide improved stability as compared to the unswept fins, but the performance gap diminished as Mach number was increased. The aerodynamic performance of the fins was not observed to degrade when the abort motors were turned on. Results from these tests indicate that grid fins can be a robust solution for stabilizing the Orion LAV over a wide

  11. Enhanced Heat Exchanger with Offset Spine Fin Design

    Kempiak, Michael; Junge, Brent

    2014-01-01

    An Offset Spine Fin Spine (segmented) fin coils have been used in certain applications as a result of their effective use of coil material. One can improve coil heat transfer performance by adding more fins per inch (FPI). This comes at the expense of air side pressure drop, which requires more fan energy to achieve the same air flow. When this type of fin is used in an evaporator, there is a secondary penalty associated with the fan heat that must be removed by the refrigeration system. Also...

  12. Lightweight Radiator Fins for Space Nuclear Power Project

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate concept radiator fins that incorporate novel carbon materials for improved performance of segmented high temperature...

  13. Fin o metamorfosis de la escuela

    José Joaquín Brunner

    1996-10-01

    Full Text Available El autor adhiere a la idea de que la escuela una es una de las matrices de la modernidad por cuanto separa la transmisión cultural de cualquier soporte físico (escritura, radicándola en el propio proceso de escolarización: su gramática consistiría en redes de clasificación del conocimiento, siendo el orden escolar esencialmente un procedimiento; el juego que juega la escuela es el de la obtención de los usos de adquisición del conocimiento. De esta forma el “fin de la escritura” como tecnología predominante del conocimiento, significara el conocimiento de una nueva era de escolarización.

  14. FinFET modeling for IC simulation and design

    Hu, Chenming; Lu, Darsen D

    2015-01-01

    This book is the first to explain FinFET modeling for IC simulation and the industry standard - BSIM-CMG - describing the rush in demand for advancing the technology from planar to 3D architecture, as now enabled by the approved industry standard. The book gives a strong foundation on the physics and operation of FinFET, details aspects of the BSIM-CMG model such as surface potential, charge and current calculations, and includes a dedicated chapter on parameter extraction procedures, providing a step-by-step approach for the efficient extraction of model parameters. With this book you will learn: * Why you should use FinFET* The physics and operation of FinFET* Details of the FinFET standard model (BSIM-CMG)* Parameter extraction in BSIM-CMG* FinFET circuit design and simulation * Authored by the lead inventor and developer of FinFET, and developers of the BSIM-CM standard model, providing an experts' insight into the specifications of the standard* The first book on the industry-standard FinFET model - BSIM...

  15. Dehumidification in greenhouses by condensation on finned pipes

    Campen, J.C.; Bot, G.P.A.

    2001-01-01

    In this study, an experimental dehumidifying system for greenhouses is tested. The system uses finned pipes fixed under the gutter of the greenhouse. The pipes are cooled below the dewpoint of the greenhouse air by cold water. The humid air passes the pipe and fins by natural convection and condensa

  16. A characteristic correlation for heat transfer over serrated finned tubes

    Highlights: • Numerical investigation og heat transfer over serrated finned tubes. • Fins used on the outside of the tubes of a sodium to air heat exchanger. • RANS approach with RNG k–ε model to handle turbulence to handle closure. • Validation with in-house experiments. • Parametric studies culminating in a correlation for Nusselt number. - Abstract: Conjugate heat transfer from serrated fins on the outside of the tubes of a sodium to air tubular heat exchanger of sodium cooled fast breeder reactors, has been investigated by combined experimental and computational approaches. For the latter approach, the RNG k–ε model, which is applicable for a wide range of Reynolds numbers, was used for turbulence closure. The numerical model employed was validated by conducting in-house heat transfer experiments on a single serrated finned tube. A detailed parametric study has been carried out to investigate the effect of serration depth, fin pitch, fin height and fin thickness. In addition to pure cross flow, the effect of angle of attack of the flow on the heat transfer also has been studied. A correlation for determining the Nusselt number over a serrated finned tube has been proposed taking into account the serration parameters. This is expected to be useful in the design of sodium to air heat exchangers of fast breeder reactors

  17. Performance Evaluation of Plate-Fin-And Tube Heat Exchanger with Wavy Fins- A Review

    Sandip S. Kale; V.W.Bhatkar

    2014-01-01

    The plate fin-and-tube heat exchangers are widely used in variety of industrial applications, particularly in the heating, air-conditioning and refrigeration, HVAC industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. It is seen that the performance of heat exchangers can be greatly increased with the use of unconventionally shaped flow passages such as plain, perforated offset strip, louvered, wavy, vortex generator an...

  18. Replacement fin processing for III-V on Si: From FinFets to nanowires

    Waldron, Niamh; Merckling, Clement; Teugels, Lieve; Ong, Patrick; Sebaai, Farid; Barla, Kathy; Collaert, Nadine; Thean, Voon-Yew (Aaron)

    2016-01-01

    In this paper we review the details and results of the replacement fin process technique used to successfully demonstrate InGaAs based channel devices from FinFets to ultra scaled nanowires on 300 mm Si substrates. For FinFet devices a Mg p-type doping solution was developed to counteract the unintentional n-type doping of the InP buffer layer which resulted in high source-drain leakage. However, the performance of these devices is found to be limited by the Mg doping as the mobility is degraded. By switching to a GAA architecture the problem of source-leakage through the InP buffer is effectively eliminated and best devices with LG = 60 nm have a peak transconductance of 1030 μS/μm with a SSSAT of 125 mV/dec are achieved. A comparison of gate first to gate last processing highlights the importance of using a low thermal budget process to maintain the integrity of the InGaAs/high-K interface. Nanowires with a diameter of 6 nm were demonstrated to show quantization induced immunity to Dit resulting in a SSSAT as low as 66 mV/dec for 85 nm LG devices.

  19. Hydrodynamics of a robotic fish tail: effects of the caudal peduncle, fin ray motions and the flow speed.

    Ren, Ziyu; Yang, Xingbang; Wang, Tianmiao; Wen, Li

    2016-02-01

    Recent advances in understanding fish locomotion with robotic devices have included the use of biomimetic flapping based and fin undulatory locomotion based robots, treating two locomotions separately from each other. However, in most fish species, patterns of active movements of fins occur in concert with the body undulatory deformation during swimming. In this paper, we describe a biomimetic robotic caudal fin programmed with individually actuated fin rays to mimic the fin motion of the Bluegill Sunfish (Lepomis macrochirus) and coupled with heave and pitch oscillatory motions adding to the robot to mimic the peduncle motion which is derived from the undulatory fish body. Multiple-axis force and digital particle image velocimetry (DPIV) experiments from both the vertical and horizontal planes behind the robotic model were conducted under different motion programs and flow speeds. We found that both mean thrust and lift could be altered by changing the phase difference (φ) from 0° to 360° between the robotic caudal peduncle and the fin ray motion (spanning from 3 mN to 124 mN). Notably, DPIV results demonstrated that the caudal fin generated multiple wake flow patterns in both the vertical and horizontal planes by varying φ. Vortex jet angle and thrust impulse also varied significantly both in these two planes. In addition, the vortex shedding position along the spanwise tail direction could be shifted around the mid-sagittal position between the upper and lower lobes by changing the phase difference. We hypothesize that the fish caudal fin may serve as a flexible vectoring propeller during swimming and may be critical for the high maneuverability of fish. PMID:26855405

  20. Numerical and Experimental Research on Modular Oscillating Fin

    Yong-hua Zhang; Yan Song; Jie Yang; K. H. Low

    2008-01-01

    Fishes are famous for their ability to position themselves accurately even in turbulent flows. This ability is the result of the coordinated movement of fins which extend from the body. We have embarked on a research program designed to develop an agile and high efficient biologically inspired robotic fish based on the performance of hybrid mechanical fins. To accomplish this goal, a mechanical ray-like fin actuated by Shape Memory Alloy (SMA) is developed, which can realize both oscillatory locomotion and undulatory locomotion. We first give a brief introduction on the mechanical structure of our fin and then carr yout theoretic analysis on force generation. Detailed information of these theoretical results is later revealed by Computational Fluid Dynamic (CFD), and is final validated by experiments. This robotic fin has potential application as a propulsor for future underwater vehicles in addition to being a valuable scientific instrument.

  1. Cryopreservation of goldfish fins and optimization for field scale cryobanking.

    Moritz, Charlotte; Labbe, Catherine

    2008-06-01

    When gametes and embryos are not available, cryobanking of somatic tissues is one possibility to keep a genetic record of fish valuables in a context of biodiversity conservation and animal breeding management. Cryopreservation of whole fin pieces would be more advantageous than the commonly used cryopreservation of cells after fin culture, as it would allow extensive sampling without immediate need for laboratory facilities. The objective of this work was to assess the cryopreservation ability of fin pieces from goldfish (Carassius auratus) and to test whether a laboratory procedure could be adapted to field conditions. Caudal fin explants were cryopreserved in culture medium with 125mM sucrose and 10% Me(2)SO. After 14days of culture, the frozen-thawed explants showed the same cell growth rate and grew the same somatic cell number as the fresh ones. Cells proliferated inside and around the explants as shown by BrdU labeling. Neither the size of the fin pieces nor the freezer type, -70 degrees C upright or -20 degrees C chest, influenced the outcome of cryopreservation. Fin pieces were stored 4days at 4 degrees C in dry conditions prior to cryopreservation without alteration of the fin explant culture success. This study demonstrated that field collecting of goldfish fin pieces is possible as whole fin pieces can be stored in standard fridge or be shipped at subzero temperature before they are frozen into a plain -20 degrees C chest freezer. After incorporation in cryobanks in liquid nitrogen, thawed fin pieces reliably produce somatic cells in cell culture conditions. PMID:18346725

  2. Fabrication of AlGaN/GaN Ω-shaped nanowire fin-shaped FETs by a top-down approach

    Im, Ki-Sik; Sindhuri, Vodapally; Jo, Young-Woo; Son, Dong-Hyeok; Lee, Jae-Hoon; Cristoloveanu, Sorin; Lee, Jung-Hee

    2015-06-01

    An AlGaN/GaN-based Ω-shaped nanowire fin-shaped FET (FinFET) with a fin width of 50 nm was fabricated using tetramethylammonium hydroxide (TMAH)-based lateral wet etching. An atomic layer deposited (ALD) HfO2 side-wall layer served as the etching mask. ALD Al2O3 and TiN layers were used as the gate dielectric and gate metal, respectively. The Ω-shaped gate structure fully depletes the active fin body and almost completely separates the depleted fin from the underlying thick GaN buffer layer, resulting in superior device performance. The top-down processing proposed in this work provides a viable pathway towards gate-all-around devices for III-nitride semiconductors.

  3. Evaluating the Fin-ray Trajectory Tracking of Bio-inspired Robotic Undulating Fins via an Experimental-numerical Approach

    Xiaojia Xiang

    2014-07-01

    Full Text Available In the past decade, biomimetic undulating fin propulsion has been one of the main topics considered by scientists and researchers in the field of robotic fish. This technology is inspired by the biological wave-like propulsion of ribbon-finned fish. The swimming modes have aquatic application potentials with greater manoeuvrability, less detectable noise or wake and better efficiency at low speeds. The present work concentrates on the evaluation of fin-ray trajectory tracking of biorobotic undulating fins at the levels of kinematics and hydrodynamics by using an experimental-numerical approach. Firstly, fin-ray tracking inconsistence between the desired and actual undulating trajectories is embodied with experimental data of the fin prototype. Next, the dynamics' nonlinearity is numerically and analytically unveiled by using the computational fluid dynamics (CFD method, from the viewpoint of vortex shedding and the hydro-effect. The evaluation of fin-ray tracking performance creates a good basis for control design to improve the fin-ray undulation of prototypes.

  4. The role of tip deflection on the thrust produced by rigid flapping fins

    Huera-Huarte, Francisco; Gharib, Morteza

    2015-11-01

    It is well known that flexibility plays an important role in the propulsion performance and efficiency of oscillating fin based propulsion systems. Compliance is one of the aspects that has received more attention, as it seems to be a common feature in nature's flyers and swimmers. Active control strategies are also common in nature. We will show how by deflecting only the last 10% of length of a rigid fin, at the tip, the thrust can be changed dramatically. This can be thought as an alternative to passive flexibility for controlling very efficiently the momentum transfer in the wake and therefore the thrust generation when flapping. A series of experiments have been carried with a robotic fin that allowed the control of its flapping kinematics as well as the control of the motions of its tip independently. We will be showing situations in which the tip was kept at a certain fixed position during a power stroke, and others in which it moved either in-phase or out-of-phase with the fin. The observed thrust and wake dynamics will be discussed for all these situations. The authors would like to acknowledge the financial support provided by the Gordon and Betty Moore Foundation and by the Spanish Ministerio de Economia y competitividad (MINECO) through grant DPI2012-37904. Visiting Associate in Aerospace, California Institute of Technology.

  5. The hydrodynamics of ribbon-fin propulsion during impulsive motion.

    Shirgaonkar, Anup A; Curet, Oscar M; Patankar, Neelesh A; Maciver, Malcolm A

    2008-11-01

    Weakly electric fish are extraordinarily maneuverable swimmers, able to swim as easily forward as backward and rapidly switch swim direction, among other maneuvers. The primary propulsor of gymnotid electric fish is an elongated ribbon-like anal fin. To understand the mechanical basis of their maneuverability, we examine the hydrodynamics of a non-translating ribbon fin in stationary water using computational fluid dynamics and digital particle image velocimetry (DPIV) of the flow fields around a robotic ribbon fin. Computed forces are compared with drag measurements from towing a cast of the fish and with thrust estimates for measured swim-direction reversals. We idealize the movement of the fin as a traveling sinusoidal wave, and derive scaling relationships for how thrust varies with the wavelength, frequency, amplitude of the traveling wave and fin height. We compare these scaling relationships with prior theoretical work. The primary mechanism of thrust production is the generation of a streamwise central jet and the associated attached vortex rings. Under certain traveling wave regimes, the ribbon fin also generates a heave force, which pushes the body up in the body-fixed frame. In one such regime, we show that as the number of waves along the fin decreases to approximately two-thirds, the heave force surpasses the surge force. This switch from undulatory parallel thrust to oscillatory normal thrust may be important in understanding how the orientation of median fins may vary with fin length and number of waves along them. Our results will be useful for understanding the neural basis of control in the weakly electric knifefish as well as for engineering bio-inspired vehicles with undulatory thrusters. PMID:18931321

  6. Novel FinFET Device Using Asymmetric Doping

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional symm...... symmetric FinFET devices. We note a reduction in sub-threshold swing (SS) of 16% with 7% Ion degradation. The proposed FinFETs can be utilized in SRAM cells and logic circuits to improve their functionality at ultra-scaled technologies....

  7. Air cooling effect of fins on a Honda shine bike

    Padhiyar Abhesinh J; Vasim G Machhar

    2015-01-01

    The main of aim of this work is to study various researches done in past to improve heat transfer rate of cooling fins by changing cylinder block fin geometry. Low rate of heat transfer through cooling fins is the main problem in this type of cooling. So efficiency of the engine is increase by increase the heat transfer. Examples of direct air cooling in modern automobiles are rare. The most common example is the commercials Automobile bike like a Honda Shine, Bajaj bike, Honda sp...

  8. El proteccionismo de fin de siglo

    Marcela SABATÉ SORT

    2010-02-01

    Full Text Available RESUMEN: Dentro del análisis de la política comercial de la Europa continental, este trabajo profundiza en la reacción proteccionista que, contrastando con la apertura anterior, caracteriza el final del siglo XIX y los primeros años del XX, justo hasta el comienzo de la Gran Guerra. Para ello indaga en los factores, especialmente las consecuencias de la "Gran Depresión", que provocan este cambio, en las políticas comerciales de los principales países europeos ante la crisis y en los niveles de protección establecidos. Unas reflexiones finales sobre el común movimiento de elevación arancelaria que preside la evolución de las políticas comerciales del continente en esta etapa y el diverso grado de protección decidido, permiten definir con exactitud la reacción proteccionista realmente acometida. Palabras Clave. Política comercial, Proteccionismo, Crisis económica, Estado, Fin de siglo. ABSTRACT: Within the analysis of the commercial policy of continental Europe, this study delves deeper into the protectionist reaction which, in contrast with the former openness, characterised the end of the nineteenth century and the beginning of the twentieth, right up until he beginning of the Great War. It inquires into the factors that provoked this change, especially the consequences of the Great Depression, and into the commercial policies of the main European countries in the face of this crisis, as well as the levels of protection established. Some final reflections on the common movement to raise tariffs which presided the evolution of the continent's commercial policies during this stage and the diverse degree of protection decided on make it possible to precisely define the protectionist action really undertaken. Key Words: Commercial Policy, Protectionism, Economic Crisis, State, Turn of the Century.

  9. Steady-state and transient heat transfer through fins of complex geometry

    Taler Dawid

    2014-06-01

    Full Text Available Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.

  10. NUMERICAL SIMULATION OF FISH SWIMMING WITH RIGID PECTORAL FINS

    XU Yi-gang; WAN De-cheng

    2012-01-01

    The numerical simulation of the self-propelled motion of a fish with a pair of rigid pectoral fins is presented.A Navier-Stokes equation solver incorporating with the multi-block and overset grid method is developed to deal with the multi-body and moving body problems.The lift-based swimming mode is selected for the fin motion.In the lift-based swimming mode,the fin can generate great thrust and at the same tune have no generation of lift force.It can be found when a pair of rigid pectoral fins generates the hydrodynamic moment,it may also generate a lateral force opposite to the centripetal direction,which has adverse effect on the turn motion of the fish.Furthermore,the periodic vortex structure generation and shedding,and their effects on the generation of hydrodynamic force are also demonstrated in this article.

  11. Flexible nanoscale high-performance FinFETs

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  12. Magnetoresistance measurement of permalloy thin film rings with triangular fins

    Magnetization reversals in permalloy rings controlled by nucleation sites using triangular fins at the same side and diagonal with respect to the field direction are demonstrated by magnetoresistance measurement and micromagnetic simulation. In the ring with triangular fins at the same side, there exists two-step reversal from onion to flux-closure state (or vortex state) and then from flux-closure (or vortex state) to reverse onion state; in the ring with diagonal triangular fins, one-step reversal occurs directly from onion to reverse onion state. The reversal processes are repeatable and controllable in contrast to an ideal ring without triangular fins where one-step and two-step reversals occur randomly in sweep-up and sweep-down processes.

  13. Simulation of thermo-mechanical effect in bulk-silicon FinFETs

    Burenkov, Alex; LORENZ, Jürgen

    2016-01-01

    The thermo-mechanical effect in bulk-silicon FinFETs of the 14 nm CMOS technology node is studied by means of numerical simulation. The electrical performance of such devices is significantly enhanced by the intentional introduction of mechanical stress during the device processing. The thermo-mechanical effect modifies the mechanical stress distribution in active regions of the transistors when they are heated. This can lead to a modification of the electrical performance. Numerical simulati...

  14. Blue and fin whale acoustics and ecology off Antarctic Peninsula

    Sirovic, Ana

    2006-01-01

    Blue (Balaenoptera musculus) and fin whales (B. physalus) in the Southern Ocean were subjects of extensive whaling industry during the twentieth century. Their current population numbers remain low, making population monitoring using traditional visual surveys difficult. Both blue and fin whales produce low frequency, regularly repeated calls and are suitable for acoustic monitoring. Eight, continuously recording acoustic recorders were deployed off the Western Antarctic Peninsula (WAP) betwe...

  15. Aerodynamic assessment of humpback whale ventral fin shapes

    Rita Espasa, Damià

    2011-01-01

    The ventral fins of the humpback whale (Megaptera novaeangliae) include a bulbous leading edge acting as a natural high-lift device. It has been suggested that application of this concept to wing design may yield advantages over traditional shapes (Miklosovic, et al., 2004). During the course of this project, the aerodynamic performance of whale fin models will be compared with conventional wing shapes. Based on the results of the study new wing design paradigms will be developed to improve t...

  16. Fin characteristics of aerator devices with lateral deflectors

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  17. Fin propulsion on a human-powered submarine

    Anderson, Iain A.; Pocock, Benjamin; Harbuz, Antoni; Algie, Cam; Vochezer, Daniel; Chao, Ryan; Lu, Benjamin

    2015-03-01

    Nearly all surface and underwater vessels are driven by screw propulsion; ideal for coupling to rotary engines and well understood after over a century of development. But most aquatic creatures use fins for swimming. Although there are sound evolutionary reasons why fish have fins and not propellers, they are nevertheless agile, fast and efficient. Although fish-like robots such as the MIT Robotuna are providing good insight into fin-based swimming there are advantages for using humans in the experimental device. Like an airplane test pilot they can write crash reports. We present preliminary observations for the human powered finned submarine: Taniwha. The sub participated in the 2nd European International Submarine races in Gosport UK where it received a trophy for "Best Non-Propeller Performance". Two sets of Hobie Mirage fin drives fixed to the upper and lower rear surfaces of the sub are pedaled by the pilot. The pilot also has two levers at the front, one to pitch a pair of dive planes and one for yawing a large rudder. Good speed, we estimate to be greater than 6 m/s is possible with these fins although we haven't explored their full potential. Straying too near the surface or bottom can lead to an instability, synonymous to a stall, such that control is lost. The mechanism for this will be discussed and solutions offered. Fish are 400 million years in front of us but one day we'll catch them.

  18. Magneto-mechanical actuation model for fin-based locomotion

    Carbajal, Juan Pablo; 10.2495/DN100331

    2011-01-01

    In this paper, we report the results from the analysis of a numerical model used for the design of a magnetic linear actuator with applications to fin-based locomotion. Most of the current robotic fish generate bending motion using rotary motors which implies at least one mechanical conversion of the motion. We seek a solution that directly bends the fin and, at the same time, is able to exploit the magneto-mechanical properties of the fin material. This strong fin-actuator coupling blends the actuator and the body of the robot, allowing cross optimization of the system's elements. We study a simplified model of an elastic element, a spring-mass system representing a flexible fin, subjected to nonlinear forcing, emulating magnetic interaction. The dynamics of the system is studied under unforced and periodic forcing conditions. The analysis is focused on the limit cycles present in the system, which allows the periodic bending of the fin and the generation of thrust. The frequency, maximum amplitude and cente...

  19. Stress analysis of plate-fin structures in recuperator

    A high performance compact recuperator with 95% effectiveness is required to achieve a high thermal efficiency power generation of up to 50% in High Temperature Gas Cooled Reactor (HTGR) coupled with closed cycle helium gas turbine. Though a plate-fin type heat exchanger is proposed for this recuperator, much research and development works are needed to establish this high performance goal since there exists no state-of-the-art technology in such a high pressure and high temperature one. One of the important works is to establish the structural analysis and evaluation method in this plate-fin type heat exchanger. This paper describes the results of stress analysis of the plate-fin structure under the internal pressure as the first step of this work. First, the modeling of a unit plate-fin structure for the analysis was examined and a three layers model was confirmed to be most adequate. The stress distribution within the structure was clarified by using this model. Second, the three layers model was simplified to one layer model with sufficient accuracy. By using this model, both the effects of an inclined angle of fin and a thickness of separate on the strength were examined parametrically. Under the relevant design conditions, it was revealed that the optimum inclined angle of fin locates in the neighborhood of 76 degree rather than most difficult fabrication angle 90 degree and there is possibility to adopt thinner thickness than 0.5 mm in the current design. (author)

  20. Evaluation Performance ofan Annular Composite Fin by UsingMATLAB Programming

    Padma Lochannayak; suvendumohanty

    2015-01-01

    The aim of this project is analysis the efficiency ratio in an annular fin by the variation of heat transfer coefficient for any surface condition by using MATLAB software to calculate the base fin efficiency and the coated fin efficiency by the variation of heat transfer coefficient, radius ratio and base fin thickness of an annular fin and compare the coating fin efficiency to base fin efficiency. If the heat transfer coefficient is 50W/m2K the increase efficiency ratio is 10.46...

  1. Temperature-time distribution and thermal stresses on the RTG fins and shell during water cooling

    Turner, R. H.

    1983-01-01

    Radioisotope thermoelectric generator (RTG) packages designed for space missions generally do not require active cooling. However, the heat they generate cannot remain inside of the launch vehicle bay and requires active removal. Therefore, before the Shuttle bay door is closed, the RTG coolant tubes attached to the heat rejection fins must be filled with water, which will circulate and remove most of the heat from the cargo bay. There is concern that charging a system at initial temperature around 200 C with water at 24 C can cause unacceptable thermal stresses in the RTG shell and fins. A computer model is developed to estimate the transient temperature distribution resulting from such charging. The thermal stresses resulting from the temperature gradients do not exceed the elastic deformation limit for the material. Since the simplified mathematical model for thermal stresses tends to overestimate stresses, it is concluded that the RTG can be cooled by introducing water at 24 C to the initially hot fin coolant tubes while the RTG is in the Shuttle cargo bay.

  2. 3D modeling of dual-gate FinFET.

    Mil'shtein, Samson; Devarakonda, Lalitha; Zanchi, Brian; Palma, John

    2012-01-01

    The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at Vg1 >Vg2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device. PMID:23148493

  3. Fouling of HVAC fin and tube heat exchangers

    Fin and tube heat exchangers are used widely in residential, commercial and industrial HVAC applications. Invariably, indoor and outdoor air contaminants foul these heat exchangers. This fouling can cause decreased capacity and efficiency of the HVAC equipment as well as indoor air quality problems related to microbiological growth. This paper describes laboratory studies to investigate the mechanisms that cause fouling. The laboratory experiments involve subjecting a 4.7 fins/cm (12 fins/inch) fin and tube heat exchanger to an air stream that contains monodisperse particles. Air velocities ranging from 1.5-5.2 m/s (295 ft/min-1024 ft/min) and particle sizes from 1-8.6(micro)m are used. The measured fraction of particles that deposit as well as information about the location of the deposited material indicate that particles greater than about 1(micro)m contribute to fouling. These experimental results are used to validate a scaling analysis that describes the relative importance of several deposition mechanisms including impaction, Brownian diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The analysis is extended to apply to different fin spacings and particle sizes typical of those found in indoor air

  4. Research on the Pin Fin Efficiency and Structure

    Fan Bailin

    2013-06-01

    Full Text Available The performance of pin fin heat sink can be to measure through the temperature field. The temperature field and efficiency of the Pin Fin were analyzed, Pin fin efficiency curve was drowned also the distribution of the temperature field along the length of the pin fin curve was drawn. Thermal resistance was composed by thermal resistance of Aluminum substrate、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regularity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the efficiency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance.

  5. Fouling of HVAC fin and tube heat exchangers

    Siegel, Jeffrey; Carey, Van P.

    2001-07-01

    Fin and tube heat exchangers are used widely in residential, commercial and industrial HVAC applications. Invariably, indoor and outdoor air contaminants foul these heat exchangers. This fouling can cause decreased capacity and efficiency of the HVAC equipment as well as indoor air quality problems related to microbiological growth. This paper describes laboratory studies to investigate the mechanisms that cause fouling. The laboratory experiments involve subjecting a 4.7 fins/cm (12 fins/inch) fin and tube heat exchanger to an air stream that contains monodisperse particles. Air velocities ranging from 1.5-5.2 m/s (295 ft/min-1024 ft/min) and particle sizes from 1--8.6 {micro}m are used. The measured fraction of particles that deposit as well as information about the location of the deposited material indicate that particles greater than about 1 {micro}m contribute to fouling. These experimental results are used to validate a scaling analysis that describes the relative importance of several deposition mechanisms including impaction, Brownian diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The analysis is extended to apply to different fin spacings and particle sizes typical of those found in indoor air.

  6. A Three-Dimensional Kinematics Analysis of a Koi Carp Pectoral Fin by Digital Image Processing

    Lei Wang; Min Xu; Bo Liu; Kin Huat Low; Jie Yang; Shiwu Zhang

    2013-01-01

    Pectoral fins fascinate researchers for their important role in fish maneuvers.By possessing a complicated flexible structure with several fin rays made by a thin film,the fin exhibits a three-dimensional (3D) motion.The complex 3D fin kinematics makes it challenging to study the performance of pectoral fin.Nevertheless,a detailed study on the 3D motion pattern of pectoral fins is necessary to the design and control ofa bio-inspired fin rays.Therefore,a highspeed photography system is introduced in this paper to study the 3D motion of a Koi Carp by analyzing the two views of its pectoral fin simultaneously.The key motions of the pectoral fins are first captured in both hovering and retreating.Next,the 3D configuration of the pectoral fins is reconstructed by digital image processing,in which the movement of fin rays during fish retreating and hovering is obtained.Furthermore,the method of Singular Value Decomposition (SVD) is adopted to extract the basic motion patterns of pectoral fins from extensive image sequences,i.e.expansion,bending,cupping,and undulation.It is believed that the movement of the fin rays and the basic patterns of the pectoral fins obtained in the present work can provide a good foundation for the development and control of bionic flexible pectoral fins for underwater propeller.

  7. Wake Vortex Structure Characteristics of a Flexible Oscillating Fin

    Zhi-dong Wang; Pei Chen; Xiao-qing Zhang

    2008-01-01

    We compute the wake of a two-dimensional and three-dimensional flexible fin in an unsteady flow field with heaving and pitching motions using FLUENT. Deflexion mode is used for a non-uniform cantilever beam with non-uniformly distributed load. The effect of chordwise deflexion length on the characteristics of propulsion is discussed for two-dimensional flexible fin.The thrust coefficient decreases, propulsive efficiency increases and the intensity of turbulence attenuates gradually as the deflexion length increases. For a three-dimensional flexible fin, the intensity of the vortex in the plane of symmetry is higher than that in the plane at 3/4 span length of the caudal fro. But the propulsive performance achieved is not what we expected with the given deflexion mode.

  8. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    Stolecki M.

    2015-09-01

    Full Text Available This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301 austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614, and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

  9. Transient thermal analysis of longitudinal fins with internal heat generation considering temperature-dependent properties and different fin profiles

    Highlights: • Transient thermal analysis of the longitudinal fins is presented. • The properties of fin are considered as a function of temperature. • An approximate technique named Hybrid DTM–FDM is used for solving the problem. • The effect of physical parameters on temperature distribution is investigated. - Abstract: The present paper aims to study the transient thermal analysis of longitudinal fins with variable cross section considering internal heat generation. The profile shapes of the fins are considered rectangular, convex, triangular and concave. It is assumed that both thermal conductivity and internal heat generation are as linear functions of temperature. The power-law temperature-dependent model is used to simulate different types of heat transfer such as laminar film boiling, natural convection, nucleate boiling and radiation. The governing equation is derived as a nonlinear partial differential equation (PDE) that is solved using a hybrid approximate technique based on the differential transform method (DTM) and finite difference method (FDM). The results are presented to study the effects of some physical parameters such as fin profile shape, thermal conductivity, convection heat transfer coefficient and internal heat generation

  10. Thermohydraulic analysis of smooth and finned annular ducts

    The present work is concerned with the turbulent heat transfer and pressure drop in smooth and finned annular ducts overage heat transfer coefficients have been obtained by means of the heat exchanger theory. In addition, friction factors have also been determined. The experiments were performed by utilizing four double-pipe heat exchangers. The flowing fluids, in the heat exchangers, were air and water. The average heat transfer coefficients, for air flowing in the annular section, were determined by measuring the overall heat transfer coefficients of the heat exchangers. In order to attain fully developed conditions, the heat exchangers had a starting length of 30 hydraulic diameters. The thermal boundary conditions consisted of uniform temperature on the inner surface, the outer surface being insulated. The heat transfer coefficients and friction factors are presented in dimensionaless forms, as functions of the Reynolds number of the flow. The results for the smooth and finned annular ducts were compared. The purpose of such comparison was to study the influence of the fins on the pressure drop and heat transfer rate. In the case of the finned nular ducts, it is shown that the fin efficiency has some fluence on the heat transfer rates. The, a two-dimensional at transfer analysis was performed in order to obtain the n efficiency and the annular region efficiency. It is also shown that the overall thermal performance of finned surfaces epends mainly on the Nusselt number and on the region eficiency. These parameters are presented as functions of the Reynolds number of the flow and the geometry of the problem. (author)

  11. Investigation of Heat Transfer Through Fins Using Fem

    Mr. H.N. Gandate

    2014-10-01

    Full Text Available Analysis of heat distribution, thermal stresses and strain for engine cylinder and fins are discussed in this paper. The cylinder and fins being analysed using finite (FE software ANSYS AND by FE (simple model. When a cylinder is subjected to certain pressure and temperature thermal distribution and thermal stresses analysis of cylinder is necessary to avoid the failure during working condition. In this work the temperature distribution and thermal stresses are evaluated by considering only temperature effect, temperature and gas pressure effect and also evaluate the same by considering the effect of cylinder head.

  12. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured...

  13. Numerical simulation and experimental verification on thermal performance of a novel fin-plate thermosyphon

    Numerical investigation of a novel fin-plate thermosyphon (FPT), used to cool the high heat dissipation electronic devices, was performed. Three dimensional model of FPT is established using the Fluent software. The effects of fin pinch, fin thickness and fin type at the air side on thermal characteristics of FPT are presented with the air flow velocity various from 1.0 m/s to 4.0 m/s. The numerical results showed a good agreement with the corresponding experimental data. The heat transfer efficiency and pressure drops of FPT for plain fins were reduced by increasing the fin space. It also can be indicated that the cooling performance of FPT with serrated fins was better than plain fins for the same structural parameters. - Highlights: ► A novel diffusion welded fin-plate thermosyphon (FPT) was designed and performed. ► The plain fins heat transfer efficiency increases with the decrease of fin spaces. ► The fin thickness is less influential on FPT performance. ► Thermal performance of serrated fins is significantly much higher than that of plain fins.

  14. Evaluation Performance ofan Annular Composite Fin by UsingMATLAB Programming

    Padma Lochannayak

    2015-04-01

    Full Text Available The aim of this project is analysis the efficiency ratio in an annular fin by the variation of heat transfer coefficient for any surface condition by using MATLAB software to calculate the base fin efficiency and the coated fin efficiency by the variation of heat transfer coefficient, radius ratio and base fin thickness of an annular fin and compare the coating fin efficiency to base fin efficiency. If the heat transfer coefficient is 50W/m2K the increase efficiency ratio is 10.46 – 28.02% for zinc coating fin from the literature but the MATLAB result is 9.3 - 25.54% , the gain efficiency ratio at thicker base fin (d=0.001m is 11.72%, at the thinner base fin (d=0.0002m is 33.57% from the literature but the MATLAB result is 7.45% (d=0.001m and 32.14% (d=0.0002m for zinc coating fin and the gain efficiency ratio at thicker base fin (d=0.001m is 11.92%, at the thinner base fin (d=0.0002m is 33.61% from the literature but the MATLAB result is 7.51% (d=0.001m and 32.16% (d=0.0002m for zinc alloy coating fin.

  15. A high density FinFET one-time programmable cell with new intra-fin cell isolation for advanced system on chip applications

    Chen, Yu-Zheng; Yuan, Jo En; Peng, Ping Chun; Hsiao, Woan Yun; King, Ya-Chin; Lin, Chrong Jung

    2016-04-01

    A fully CMOS compatible one-time programmable (OTP) cell with a novel intra-fin cell isolation (IFCI) structure on a FinFET CMOS process has been proposed. The IFCI OTP cell utilizes the field-enhanced dielectric breakdown at fin corners to perform a fast and low-voltage program operation. Moreover, an ultrasmall intra-fin cell-to-cell isolation is firstly introduced to markedly shrink the cell size by eliminating the area-consuming spacing of fin-to-fin isolation. The IFCI FinFET OTP with fast program speed, excellent read disturb immunity, and reliable data retention is a promising solution for logic nonvolatile memory (NVM) technology in advanced CMOS nodes.

  16. Numerical study of an innovative design of a finned double-pipe heat exchanger with variable fin-tip thickness

    Highlights: • Variable fin tip angle significantly effect the velocity and temperature distribution. • Significant gain in the thermal performance with decrease in the friction factor. • Variable fin tip angle must be considered an important parameter in designing finned annulus. - Abstract: The analysis of fully developed laminar convective heat transfer in an innovate design of a finned double-pipe heat exchanger (DPHE) with longitudinal fins of variable thickness of the tip subjected to the constant heat transfer rate boundary conditions is investigated here. The tip thickness is controlled by the ratio of tip to base angles as a parameter whose values varying from 0 to 1 correspond to the fin shapes varying from the triangular to the rectangular cross-section. Upto the knowledge of the authors, this parameter is being introduced for the first time in the literature. Discontinuous Galerkin finite element method (DG-FEM) has been employed in the present work. The overall performance of the proposed DPHE has been investigated by considering the friction factor, the Nusselt number and the j-factor. Upto 178% gain in the Nusselt number and 89% gain in the j-factor have been achieved relative to the rectangular cross-section. Such gains relative to the triangular cross-section are respectively 9.5% and 19%. The results indicate that the newly introduced parameter the ratio of tip to base angles has proved to play significant role in the design of a double-pipe heat exchanger in reducing the cost, weight and frictional loss, in improving the heat transfer rate and making the exchanger energy-efficient. Therefore, it must be considered as an important design parameter for heat exchanger design

  17. DSA patterning options for FinFET formation at 7nm node

    Liu, Chi-Chun C.; Franke, Elliott; Lie, Fee Li; Sieg, Stuart; Tsai, Hsinyu; Lai, Kafai; Truong, Hoa; Farrell, Richard; Somervell, Mark; Sanders, Daniel; Felix, Nelson; Guillorn, Michael; Burns, Sean; Hetzer, David; Ko, Akiteru; Arnold, John; Colburn, Matthew

    2016-03-01

    Several 27nm-pitch directed self-assembly (DSA) processes targeting fin formation for FinFET device fabrication are studied in a 300mm pilot line environment, including chemoepitaxy for a conventional Fin arrays, graphoepitaxy for a customization approach and a hybrid approach for self-aligned Fin cut. The trade-off between each DSA flow is discussed in terms of placement error, Fin CD/profile uniformity, and restricted design. Challenges in pattern transfer are observed and process optimization are discussed. Finally, silicon Fins with 100nm depth and on-target CD using different DSA options with either lithographic or self-aligned customization approach are demonstrated.

  18. Thickness-varying flexible plunging fins swim more efficiently

    Li, Yuanda; Yeh, Peter; Alexeev, Alexander

    2015-11-01

    We use three dimensional computer simulations to probe the hydrodynamics of oscillating flexible fins with varying thickness. The fin is modeled as an elastic rectangular plate with the thickest section at the leading edge, decreasing linearly until the trailing edge. The plate is modeled as infinitely thin, and we assume that the thickest part of the fin is much smaller compared to its other length scales. Therefore, we simulate the swimmer as two dimensional plate and introduce the effect of the thickness gradient by including an appropriate mass gradient and stiffness gradient along the length of the plate. The flexible fin is actuated by a plunging motion at its leading edge. We evaluate the performance of the swimmer by measuring the steady state thrust, free swimming velocity, input power, and swimming economy as a function of driving frequency and the magnitude of the thickness gradient. We find a wideband frequency range in which the swimming economy is increased as compared to a uniformly thick swimmer. These findings may shed insight into some of the physical mechanisms that allow fish to have high swimming efficiency.

  19. Differential Transformation Method for Temperature Distribution in a Radiating Fin

    Rahimi, M.; Hosseini, M. J.; Barari, Amin;

    2011-01-01

    Radiating extended surfaces are widely used to enhance heat transfer between a primary surface and the environment. In this paper, the differential transformation method (DTM) is proposed for solving nonlinear differential equation of temperature distribution in a heat radiating fin. The concept of...

  20. Eddy current test of fin tubes for a heat exchanger

    Eddy current probes were designed for the test of fin tubes. Fin tubes, often used for heat exchangers, have uneven outer and inner surfaces to enhance the heat emission. The surface roughness make it difficult to detect flaws employing eddy current test(ECT). In order to overcome the difficulties we performed two types of works, one is the delopment of ECT probes, and the other is the signal processing including fast Fourier transform and digital filtering. In the development of ECT probes, we adopted empirical design method. Our ECT probes for fin tubes are inside diameter type. And we are specially concerned about geometric features such as the widths of the coils composing an ECT probe. We fabricated four probes with various coil widths. Eddy current test was performed using those ECT probes on specimens with artificial flaws. After analyzing the output signals, we found that, in order for the effective testing, the width of a coil should be determined considering the pitch of the fins of a tube. And we also learned that the frequency filtering could improve the s/n ratio.

  1. The Linear and Nonlinear Electro-MechanicalFin Actuator

    Zeina A. Abdul Redha

    2011-01-01

    Full Text Available Electromechanical actuators are used in a wide variety of aerospace applications such as missiles, aircrafts and spy-fly etc. In this work a linear and nonlinear fin actuator mathematical model has been developed and its response is investigated by developing an algorithm for the system using MATLAB. The algorithm used to the linear model is the state space algorithm while the algorithm used to the nonlinear model is the discrete algorithm. The huge moment constant is varied from (-3000 to 3000 and the damping ratio is varied from (0.4 to 0.8. The comparison between linear and nonlinear fin actuator response results shows that for linear model, the maximum overshoot is about 10%, rising time is 0.23 sec. and steady state occur at 0.51 sec., while For nonlinear model the maximum overshoot is about 5%, rising time is 0.26 sec. and steady state occurs at 2 sec.; i.e., the nonlinear fin actuator system gives faster and more accurate response than does the linear fin actuator system.

  2. Distinct roles of Shh and Fgf signaling in regulating cell proliferation during zebrafish pectoral fin development

    Neumann Carl J

    2008-09-01

    Full Text Available Abstract Background Cell proliferation in multicellular organisms must be coordinated with pattern formation. The major signaling pathways directing pattern formation in the vertebrate limb are well characterized, and we have therefore chosen this organ to examine the interaction between proliferation and patterning. Two important signals for limb development are members of the Hedgehog (Hh and Fibroblast Growth Factor (Fgf families of secreted signaling proteins. Sonic hedgehog (Shh directs pattern formation along the anterior/posterior axis of the limb, whereas several Fgfs in combination direct pattern formation along the proximal/distal axis of the limb. Results We used the genetic and pharmacological amenability of the zebrafish model system to dissect the relative importance of Shh and Fgf signaling in regulating proliferation during development of the pectoral fin buds. In zebrafish mutants disrupting the shh gene, proliferation in the pectoral fin buds is initially normal, but later is strongly reduced. Correlating with this reduction, Fgf signaling is normal at early stages, but is later lost in shh mutants. Furthermore, pharmacological inhibition of Hh signaling for short periods has little effect on either Fgf signaling, or on expression of G1- and S-phase cell-cycle genes, whereas long periods of inhibition lead to the downregulation of both. In contrast, even short periods of pharmacological inhibition of Fgf signaling lead to strong disruption of proliferation in the fin buds, without affecting Shh signaling. To directly test the ability of Fgf signaling to regulate proliferation in the absence of Shh signaling, we implanted beads soaked with Fgf protein into shh mutant fin buds. We find that Fgf-soaked beads rescue proliferation in the pectoral find buds of shh mutants, indicating that Fgf signaling is sufficient to direct proliferation in zebrafish fin buds in the absence of Shh. Conclusion Previous studies have shown that both

  3. Open Channel Natural Convection Heat Transfer on a Vertical Finned Plate

    Park, Joo Hyun; Heo, Jeong Hwan; Chung, Bum Jin [Kyung Hee Univ., Yongin (Korea, Republic of)

    2013-10-15

    The natural convection heat transfer of vertical plate fin was investigated experimentally. Heat transfer systems were replaced by mass-transfer systems, based on the analogy concept. The experimental results lie within the predictions of the existing heat transfer correlations of plate-fin for the natural convections. An overlapped thermal boundary layers caused increasing heat transfer, and an overlapped momentum boundary layers caused decreasing heat transfer. As the fin height increases, heat transfer was enhanced due to increased inflow from the open side of the fin spacing. When fin spacing and fin height are large, heat transfer was unaffected by the fin spacing and fin height. Passive cooling by natural convection becomes more and more important for the nuclear systems as the station black out really happened at the Fukushima NPPs. In the RCCS (Reactor Cavity Cooling System) of a VHTR (Very High Temperature Reactor), natural convection cooling through duct system is adopted. In response to the stack failure event, extra cooling capacity adopting the fin array has to be investigated. The finned plate increases the surface area and the heat transfer increases. However, the plate of fin arrays may increase the pressure drop and the heat transfer decreases. Therefore, in order to enhance the passive cooling with fin arrays, the parameters for the fin arrays should be optimized. According to Welling and Wooldridge, a natural convection on vertical plate fin is function of Gr, Pr, L, t, S, and H. The present work investigated the natural convection heat transfer of a vertical finned plate with varying the fin height and the fin spacing. In order achieve high Rayleigh numbers, an electroplating system was employed and the mass transfer rates were measured using a copper sulfate electroplating system based on the analogy concept.

  4. Eddy-Current Testing of Finned Fuel Cladding

    Eddy-current methods of testing reactor-fuel components are well established. The literature, however, mainly describes tests which are applied to simple geometries such as cylindrical rods or tubes. Recent AECL fuel designs have called for cladding with heat transfer or locating fins along the length of the fuel. This paper describes the application of eddy-current techniques to three such designs. The function and geometry of the fins must be considered in the selection of the optimum test parameters and the most suitable test coil geometry. Thus, the presence of fins may limit or restrict the test but they will not prevent a successful test. Where the fin geometry is complex eddy currents may well be the most suitable of the non-destructive methods which can be used for flaw detection. The thickness of aluminium cladding over a uranium core is measured with a small probe coil placed between the fins and shielded from them. Two flaw detection tests are described, one on sintered aluminium product (SAP) tubing using an internal bobbin coil and the other on an aluminium-clad uranium-aluminium alloy rod with an external encircling coil. The instrumentation described is relatively simple. A small portable instrument was designed for the cladding thickness measurement. For flaw detection a standard oscilloscope with a plug-in carrier-amplifier module provides a means of sensing and displaying the test coil impedance variations. This equipment ,although it does not permit sophisticated methods of eliminating unwanted noise is adequate for a variety of testing applications and has been specified for routine fuel testing on a production basis. (author)

  5. Changes in dive behavior during naval sonar exposure in killer whales, long-finned pilot whales, and sperm whales

    Sivle, L.D.; Kvadsheim, P. H.; Fahlman, A.; Lam, F.P.A.; Tyack, P. L.; Miller, P.J.O.

    2012-01-01

    Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1-2 kHz and mid frequency active sonar (MFAS): 6-7 kHz] during three field seasons (2...

  6. Changes in dive behavior during naval sonar exposure in killer whales, long-finned pilot whales, and sperm whales

    Lise Doksæter Sivle; Petter Helgevold Kvadsheim; Andreas eFahlman; Frans-Peter eLam; Peter eTyack; Patrick eMiller

    2012-01-01

    Anthropogenic underwater sound in the environment might potentially affect the behavior of marine mammals enough to have an impact on their reproduction and survival. Diving behavior of four killer whales (Orcinus orca), seven long-finned pilot whales (Globicephala melas), and four sperm whales (Physeter macrocephalus) was studied during controlled exposures to naval sonar [low frequency active sonar (LFAS): 1–2 kHz and mid frequency active sonar (MFAS): 6–7 kHz] during three field seasons (2...

  7. DRY/WET PERFORMANCE OF A PLATE-FIN AIR COOLED HEAT EXCHANGER WITH CONTINUOUS CORRUGATED FINS

    The report describes work to (1) determine experimentally the performance and operating characteristics of a plate-fin heat exchanger during dry/wet or 'deluge' operation and (2) continue developing the deluge heat/mass transfer model. This work supports the improvement of power ...

  8. Evaluation report of the Nordic-Baltic annex to the INEX-2-FIN-exercise April 17, 1997

    NONE

    1997-10-01

    Under the auspices of the NKS programme and as a part of EKO-4 project a special Nordic-Baltic emergency exercise was carried out. In order to rationalise exercise activities it was organised as an annex to the international INEX-2-FIN exercise arranged by the OECD/NEA on April 17, 1997. Some countries carried out simultaneous national exercises as well. Only the Nordic-Baltic exercise is discussed in this report. The objectives of the INEX-2-FIN exercise were to test real time information exchange, decision making based on plant conditions and real weather, and public information. These objectives determined the framework for the scenario and necessary scripts of the exercise. For the Nordic-Baltic annex of the exercise five more detailed objectives, subordinated to the INEX-2-FIN objectives, were defined by the planning group under EKO-4 project. Since the exercise was the first of this kind for the Baltic countries only one of the special objectives was designed for them, namely N4. An independent evaluators group, consisting of one member from each participating country plus a chairperson, was set to evaluate the Nordic-Baltic annex of the INEX-2-FIN exercise. However, because of lack of personnel in the Baltic countries the evaluators were the same persons as in the planning group. (au)

  9. Evaluation report of the Nordic-Baltic annex to the INEX-2-FIN-exercise April 17, 1997

    Under the auspices of the NKS programme and as a part of EKO-4 project a special Nordic-Baltic emergency exercise was carried out. In order to rationalise exercise activities it was organised as an annex to the international INEX-2-FIN exercise arranged by the OECD/NEA on April 17, 1997. Some countries carried out simultaneous national exercises as well. Only the Nordic-Baltic exercise is discussed in this report. The objectives of the INEX-2-FIN exercise were to test real time information exchange, decision making based on plant conditions and real weather, and public information. These objectives determined the framework for the scenario and necessary scripts of the exercise. For the Nordic-Baltic annex of the exercise five more detailed objectives, subordinated to the INEX-2-FIN objectives, were defined by the planning group under EKO-4 project. Since the exercise was the first of this kind for the Baltic countries only one of the special objectives was designed for them, namely N4. An independent evaluators group, consisting of one member from each participating country plus a chairperson, was set to evaluate the Nordic-Baltic annex of the INEX-2-FIN exercise. However, because of lack of personnel in the Baltic countries the evaluators were the same persons as in the planning group. (au)

  10. Locomotion and Depth Control of Robotic Fish with Modular Undulating Fins

    Kin Huat Low

    2006-01-01

    This paper presents an environmental-friendly robotic system mimicking the undulating fins of a fish. To mimic the actual flexible fin of real fish, a fin-like mechanism with a series of connecting linkages is modeled and attached to the robotic fish, by virtue of a specially designed strip. Each link is able to turn and slide with respect to the adjacent link.These driving linkages are then used to form a mechanical fin consisting of several fin segments, which are able to produce undulations, similar to those produced by the actual fish fins. Owing to the modular and re-configurable design of the mechanical fin, we are able to construct biomimetic robotic fish with various swimming modes by fin undulations. Some qualitative and workspace observations by experiments of the robotic fish are shown and discussed.

  11. Actuation of a robotic fish caudal fin for low reaction torque

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghee

    2011-07-01

    In this paper, a novel caudal fin for actuating a robotic fish is presented. The proposed caudal fin waves in a vertical direction with a specific spatial shape, which is determined by a so-called shape factor. For a specific shape factor, a traveling wave with a vertical phase difference is formed on a caudal fin during fin motion. It will be shown by the analysis that the maximum reaction torque at the joint of a caudal fin varies depending on the shape factors. Compared with a conventional plate type caudal fin, the proposed fin with a shape factor of 2π can eliminate the reaction torque perfectly, while keeping the propulsion force unchanged. The benefits of the proposed fin will be demonstrated by experiments.

  12. Pyramidal Fin Arrays Performance Using Streamwise Anisotropic Materials by Cold Spray Additive Manufacturing

    Cormier, Yannick; Dupuis, Philippe; Jodoin, Bertrand; Corbeil, Antoine

    2016-01-01

    This work evaluates the thermal and hydrodynamic performance of pyramidal fin arrays produced using cold spray as an additive manufacturing process. Near-net-shaped pyramidal fin arrays of pure aluminum, pure nickel, and stainless steel 304 were manufactured. Fin array characterization such as fin porosity level and surface roughness evaluation was performed. The thermal conductivities of the three different coating materials were measured by laser flash analysis. The results obtained show a lower thermal efficiency for stainless steel 304, whereas the performances of the aluminum and nickel fin arrays are similar. This result is explained by looking closely at the fin and substrate roughness induced by the cold gas dynamic additive manufacturing process. The multi-material fin array sample has a better thermal efficiency than stainless steel 304. The work demonstrates the potential of the process to produce streamwise anisotropic fin arrays as well as the benefits of such arrays.

  13. Note: Dynamic analysis of a robotic fish motion with a caudal fin with vertical phase differences

    Yun, Dongwon; Kim, Kyung-Soo; Kim, Soohyun; Kyung, Jinho; Lee, Sunghwi

    2013-03-01

    In this paper, a robotic fish with a caudal fin with vertical phase differences is studied, especially focusing on the energy consumption. Energies for thrusting a conventional robotic fish and one with caudal fin with vertical phase differences are obtained and compared each other. It is shown that a robotic fish with a caudal fin with vertical phase differences can save more energy, which implies the efficient thrusting via a vertically waving caudal fin.

  14. North Atlantic blue and fin whales suspend their spring migration to forage in middle latitudes: building up energy reserves for the journey?

    Mónica A Silva

    Full Text Available The need to balance energy reserves during migration is a critical factor for most long-distance migrants and an important determinant of migratory strategies in birds, insects and land mammals. Large baleen whales migrate annually between foraging and breeding sites, crossing vast ocean areas where food is seldom abundant. How whales respond to the demands and constraints of such long migrations remains unknown. We applied a behaviour discriminating hierarchical state-space model to the satellite tracking data of 12 fin whales and 3 blue whales tagged off the Azores, to investigate their movements, behaviour (transiting and area-restricted search, ARS and daily activity cycles during the spring migration. Fin and blue whales remained at middle latitudes for prolonged periods, spending most of their time there in ARS behaviour. While near the Azores, fin whale ARS behaviour occurred within a restricted area, with a high degree of overlap among whales. There were noticeable behavioural differences along the migratory pathway of fin whales tracked to higher latitudes: ARS occurred only in the Azores and north of 56°N, whereas in between these areas whales travelled at higher overall speeds while maintaining a nearly direct trajectory. This suggests fin whales may alternate periods of active migration with periods of extended use of specific habitats along the migratory route. ARS behaviour in blue whales occurred over a much wider area as whales slowly progressed northwards. The tracks of these whales terminated still at middle latitudes, before any behavioural switch was detected. Fin whales exhibited behavioural-specific diel rhythms in swimming speed but these varied significantly between geographic areas, possibly due to differences in the day-night cycle across areas. Finally, we show a link between fin whales seen in the Azores and those summering in eastern Greenland-western Iceland along a migratory corridor located in central Atlantic

  15. Comparative design evaluation of plate fin heat exchanger and coiled finned tube heat exchanger for helium liquefier in the temperature range of 300-80 K

    Present indigenous helium liquefaction system at RRCAT uses the cross-counter flow coiled-finned tube heat exchangers developed completely from Indian resources. These coiled-finned tube heat exchangers are mainly suitable up to medium capacity helium liquefiers. For large capacity helium liquefier, plate fin heat exchangers are more suitable options. This paper presents the comparative evaluation of the design of both types of heat exchangers in the temperature range of 300-80 K for helium liquefier. (author)

  16. Multiphysics Numerical Modeling of a Fin and Tube Heat Exchanger

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2015-01-01

    In the present research work, a modeling effort to predict the performance of a liquid-gas type fin and tube heat exchanger design is made. Three dimensional (3D) steady state numerical model is developed using commercial software COMSOL Multiphysics based on finite element method (FEM). For the...... purposes here, only gas flowing over the fin side is simulated assuming constant inner tube wall temperature. The study couples conjugate heat transfer mechanism with turbulent flow in order to describe the temperature and velocity profile. In addition, performance characteristics of the heat exchanger...... design in terms of heat transfer and pressure loss are determined by parameters such as overall heat transfer coefficient, Colburn j-factor, flow resistance factor, and efficiency index. The model provides useful insights necessary for optimization of heat exchanger design....

  17. Single basin solar still with fin for enhancing productivity

    Distilled water productivity of the single basin solar still is very low. In this work, to augment evaporation of the still basin water, fins were integrated at the basin of the still. Thus production rate accelerated. Also, for further increase in exposure area sponges were used. Experimental results were compared with ordinary basin type still and still with wicks. The governing energy balance equations were solved analytically and compared with experimental results. It was found that 29.6% productivity increased, when wick type solar still was used, 15.3% productivity increased when sponges were used and 45.5% increased when fins were used. A good agreement had been achieved with theoretical results

  18. Saddle-fin cell transistors with oxide etch rate control by using tilted ion implantation (TIS-fin) for sub-50-nm DRAMs

    As DRAM cell pitch size decreases, the need for a high performance transistor is increasing. Though saddle-fin (S-fin) transistors have superior characteristics, S-fin transistors are well known to be more sensitive to process variation. To make uniform S-fin transistors, for the first time, we developed a new fin formation method using tilted ion implantation along the wordline direction after a recess gate etch. Due to the increased etch rate of the oxide film by ion implantation damage, fins are made at the bottom channel of the recess gate after wet etching. The resulting tilt implanted saddle-fin (TIS-fin) transistor has remarkably improved characteristics, such as ∼8% subthreshold swing (SS) and a 40% drain induced barrier lowering (DIBL) decrease. Especially, the TIS-fin with a neutral dopant has a reduced threshold voltage (Vth) variation within a wafer (<100 mV), which is comparable with that of a mass-produced sphere-shaped recessed channel array transistor (SRCAT).

  19. Parametric study of propeller boss cap fins for container ships

    Lim Sang-Seop; Kim Tae-Won; Lee Dong-Myung; Kang Chung-Gil; Kim Soo-Young

    2014-01-01

    The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. This study examined the design parameters of the propeller boss cap fin (PBCF) an...

  20. An experimental study of a pin-fin heat exchanger

    Ramthun, David L.

    2003-01-01

    Approved for public release; distribution is unlimited A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins. A modular wind-tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achie...

  1. FINITE DIFFERENCE MODEL OF A CIRCULAR FIN WITH RECTANGULAR PROFILE

    GİRGİN, İbrahim; EZGİ, Cüneyt

    2015-01-01

    Numerical methods are commonly used in engineering where the analytical resultsare not reached or as a support of experimental studies. Various techniques are being usedas a numeritical method as finite difference, finite volume or finite elements, etc. In thisstudy, numerical solutions are obtained for a circular fin of rectangular profile using finitedifference method, and the results are compared to the analytical solutions. It is seen thatthe analytical solution and numerical results are ...

  2. Lionfish predators use flared fin displays to initiate cooperative hunting

    Lönnstedt, Oona M; Ferrari, Maud C. O.; Chivers, Douglas P.

    2014-01-01

    Despite considerable study, mystery surrounds the use of signals that initiate cooperative hunting in animals. Using a labyrinth test chamber, we examined whether a lionfish, Dendrochirus zebra, would initiate cooperative hunts with piscine partners. We found that D. zebra uses a stereotyped flared fin display to alert conspecific and heterospecific lionfish species Pterois antennata to the presence of prey. Per capita success rate was significantly higher for cooperative hunters when compare...

  3. Design & modelling of a composite rudderless aeroelastic fin structure

    Trapani, Matteo

    2010-01-01

    This thesis presents the study of a gapless and rudderless aeroelastic fin (GRAF) to enhance the directional stability and controllability of an aircraft. The GRAF concept was proposed and developed in the wake of previous research, targeted to improve flight performance and manoeuvrability, and to reduce fuel consumption and airframe weight. The study involved the subjects of aerodynamics, structural design and analysis, and flight mechanics. The work includes conceptual de...

  4. Dorsal and anal fin function in bluegill sunfish Lepomis macrochirus: three-dimensional kinematics during propulsion and maneuvering.

    Standen, E M; Lauder, G V

    2005-07-01

    Dorsal and anal fins are median fins located above and below the centre of mass of fishes, each having a moment arm relative to the longitudinal axis. Understanding the kinematics of dorsal and anal fins may elucidate how these fins are used in concert to maintain and change fish body position and yet little is known about the functions of these fins. Using three synchronized high-speed cameras (500 frames s(-1)) we studied the three-dimensional kinematics of dorsal and anal fins during steady swimming (0.5-2.5 TL s(-1), where TL = total length) and during slow speed maneuvers (0.5 TL s(-1)). By digitizing points along every other fin ray in the soft-rayed portion of the fins we were able to determine not only the movement of the fin surface but also the curvature of individual fin rays and the resulting fin surface shape. We found that dorsal and anal fins begin oscillating, in phase, at steady swimming speeds above 1.0 TL s(-1) and that maximum lateral displacement of the trailing edge of the fins as well as fin area increase with increasing steady swimming speed. Differences in area, lateral displacement and moment arm between the dorsal and anal fin suggest that dorsal and anal fins produce balancing torques during steady swimming. During maneuvers, fin area is maximized and mean lateral excursion of both fins is greater than during steady swimming, with large variation among maneuvers. Fin surface shape changes dramatically during maneuvers. At any given point in time the spanwise (base to tip) curvature along fin rays can differ between adjacent rays, suggesting that fish have a high level of control over fin surface shape. Also, during maneuvers the whole surface of both dorsal and anal fins can be bent without individual fin rays exhibiting significant curvature. PMID:16000544

  5. Bionic asymmetry: from amiiform fish to undulating robotic fins

    HU TianJiang; SHEN LinCheng; LOW K.H.

    2009-01-01

    Similar to bionic non-smooth which has been successfully applied in anti-resistance and anti-adhesion, bionic asymmetry is also an inherent property of biological systems and is worth exploring for con-ceivable pragmatic applications. Therefore, bionic asymmetry for undulations is of main interest in this paper. We initially investigate bionic asymmetry with a case study of the undulating robotic fin, RoboGnilos, which evolved from the long dorsal fin of Gymnarchus niloticus in the amiiforrn mode. Since the performance of the pre-existing undulating fins is hardly satisfactory, we obtain bionic in-spirations of undulatory asymmetry through observations and measurements on the specimen of G. niloticus, to improve upon the performance. Consequently, the newly acquired innovation for bionic asymmetry is incorporated into the previously derived kinematics model, and also applied to the ex-perimental prototype. Both computational and experimental results verify that bionic asymmetric un-dulation generates better propulsion performance (in terms of linear velocity and efficiency) than the traditional symmetric modes with the same undulatory parameters.

  6. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  7. Numerical Study on Hydrodynamic Performance of Bionic Caudal Fin

    Kai Zhou

    2016-01-01

    Full Text Available In this work, numerical simulations are conducted to reveal the hydrodynamic mechanism of caudal fin propulsion. In the modeling of a bionic caudal fin, a universal kinematics model with three degrees of freedom is adopted and the flexible deformation in the spanwise direction is considered. Navier-Stokes equations are used to solve the unsteady fluid flow and dynamic mesh method is applied to track the locomotion. The force coefficients, torque coefficient, and flow field characteristics are extracted and analyzed. Then the thrust efficiency is calculated. In order to verify validity and feasibility of the algorithm, hydrodynamic performance of flapping foil is analyzed. The present results of flapping foil compare well with those in experimental researches. After that, the influences of amplitude of angle of attack, amplitude of heave motion, Strouhal number, and spanwise flexibility are analyzed. The results show that, the performance can be improved by adjusting the motion and flexibility parameters. The spanwise flexibility of caudal fin can increase thrust force with high propulsive efficiency.

  8. Optimization of fin geometry in heat convection with entransy theory

    The entransy theory developed in recent years is used to optimize the aspect ratio of a plate fin in heat convection. Based on a two-dimensional model, the theoretical analysis shows that the minimum thermal resistance defined with the concept of entransy dissipation corresponds to the maximum heat transfer rate when the temperature of the heating surface is fixed. On the other hand, when the heat flux of the heating surface is fixed, the minimum thermal resistance corresponds to the minimum average temperature of the heating surface. The entropy optimization is also given for the heat transfer processes. It is observed that the minimum entropy generation, the minimum entropy generation number, and the minimum revised entropy generation number do not always correspond to the best heat transfer performance. In addition, the influence factors on the optimized aspect ratio of the plate fin are also discussed. The optimized ratio decreases with the enhancement of heat convection, while it increases with fin thermal conductivity increasing. (general)

  9. High performance flexible CMOS SOI FinFETs

    Fahad, Hossain M.

    2014-06-01

    We demonstrate the first ever CMOS compatible soft etch back based high performance flexible CMOS SOI FinFETs. The move from planar to non-planar FinFETs has enabled continued scaling down to the 14 nm technology node. This has been possible due to the reduction in off-state leakage and reduced short channel effects on account of the superior electrostatic charge control of multiple gates. At the same time, flexible electronics is an exciting expansion opportunity for next generation electronics. However, a fully integrated low-cost system will need to maintain ultra-large-scale-integration density, high performance and reliability - same as today\\'s traditional electronics. Up until recently, this field has been mainly dominated by very weak performance organic electronics enabled by low temperature processes, conducive to low melting point plastics. Now however, we show the world\\'s highest performing flexible version of 3D FinFET CMOS using a state-of-the-art CMOS compatible fabrication technique for high performance ultra-mobile consumer applications with stylish design. © 2014 IEEE.

  10. The effect of ether anesthesia on fin-clipping rate

    Eschmeyer, Paul H.

    1953-01-01

    As part of an experimental program to learn the effects of stocking lake trout (Salvelinus namaycush) in Lake Superior, 141, 392 fingerlings were marked at the Charlevoix (Michigan) Station of the U.S. Fish and Wildlife Service in October 1952. The adipose fin was removed from all fish, the right pelvic from the remainder. A random sample of 2, 417 of the fish showed an average total length of 4.0 inches (range, 2.7 to 5.4). The mean weight of all fish marked was slightly less than one-third ounce (49 fish per pound). The local women, none of whom had previous experience in the work, were employed to mark the fish. Bone-cutting forceps were used for excision of the fins, and each worker wore a bobbinet glove to facilitate handling of the fish. On alternate days the fish were anesthetized with ether before marking, to determine the effect of its use on the fin-clipping rate.

  11. The FLUFF code for calculating finned surface heat transfer -description and user's guide

    FLUFF is a computer code for calculating heat transfer from finned surfaces by convection and radiation. It can also represent heat transfer by radiation to a partially emitting and absorbing medium within the fin cavity. The FLUFF code is useful not only for studying the behaviour of finned surfaces but also for deriving heat fluxes which can be applied as boundary conditions to other heat transfer codes. In this way models of bodies with finned surfaces may be greatly simplified since the fins need not be explicitly represented. (author)

  12. Crystallographic Silicon-Etching for Ultra-High Aspect-Ratio FinFET

    Jovanovic, V.; Suligoj, T.; Nanver, L.K.

    2008-01-01

    The fabrication process for the FinFET with ultra-high fin-height to fin-width aspect-ratio is presented. The processing is based on the crystallographic etching of (110) bulk silicon-wafers by TMAH to expose the vertical (111) planes. The nitride-spacers are used as the hard-mask for the fin-etching and the fins are isolated by the planarization and etch-back of the thick isolation oxide. The demonstration devices exhibit nearly ideal S of 62-64 mV/dec and DIBL of 10 mV/V or lower, for the g...

  13. Structure optimization and performance experiments of a solar-powered finned-tube adsorption refrigeration system

    Highlights: • New-structure finned-tube adsorption bed for enhancing heat and mass transfer. • Temperatures on different parts of the adsorption tubes differ little. • Maximum COP of 0.122 and maximum daily ice-making of 6.5 kg are achieved by experiments. • Cooling efficiency of system with valve control higher than that without valve control. - Abstract: A large-diameter aluminum-alloy finned-tube absorbent bed collector was designed and optimized by enhancing the heat and mass transfer in the collector. The collection efficiency of the adsorbent bed collector was between 31.64% and 42.7%, and the temperature distribution in the absorbent bed was relatively uniform, beneficial to adsorption/desorption of the adsorbate in the absorbent bed. A solar-powered solid adsorption refrigeration system with the finned-tube absorbent bed collector was built. Some experiments corresponding to the adsorption/desorption process with and without a valve control were conducted in four typical weather conditions: sunny with clear sky, sunny with partly cloudy sky, cloudy sky and overcast sky. Activated carbon–methanol was utilized as the working pair for adsorption refrigeration in the experiments. The experiments achieved the maximum COP of 0.122 and the maximum daily ice-making of 6.5 kg. Under the weather conditions of sunny with clear sky, sunny with partly cloudy sky, and cloudy sky, ice-making phenomenon were observed. Even in the overcast-sky weather condition, the cooling efficiency of the system still reached 0.039 when the total solar radiation was 11.51 MJ. The cooling efficiency of the solar-powered adsorption refrigeration system with a valve control in the adsorption/desorption process was significantly higher than that without a valve control

  14. Fin des temps et temps de la fin dans l’univers médiéval

    Álvares, Cristina; Arrouye, Jean; Berthelot, Anne; Anca BRATU; Bureau, Pierre; Cazanave, Caroline; Charpentier, Hélène; Combarieu du Grès, Micheline de; Deluz, Christiane; Diogo, Américo; Gourc, Jacques; Gros, Gérard; Houdeville, Michelle; Hüe, Denis; Joly, Jehanne

    2014-01-01

    Ce volume rassemble les communications présentées au dix-huitième Colloque du C.U.E.R.M.A. qui s'est tenu à Aix-en-Provence en février 1993 sur le thème : FIN DES TEMPS ET TEMPS DE LA FIN AU MOYEN AGE Comme les années précédentes, nous avons utilisé les dactylogrammes fournis par les conférenciers. Ainsi les communications ont-elles la présentation exacte déterminée par leurs auteurs. Le C.U.E.R. M.A. remercie l'Université de Provence qui a fourni son aide pour l'organisation du colloque e...

  15. A successful application of homotopy perturbation method for efficiency and effectiveness assessment of longitudinal porous fins

    Highlights: • Homotopy perturbation method has been applied to porous fins. • Dimensionless efficiency and effectiveness expressions have been firstly developed. • Effects of porous and convection parameters on thermal analysis have been clarified. • Ratio of porous fin to solid fin heat transfer rate has been given for various cases. • Reliability and practicality of homotopy perturbation method has been illustrated. - Abstract: In our previous works, thermal performance of straight fins with both constant and temperature-dependent thermal conductivity has been investigated in detail and dimensionless analytical expressions of fin efficiency and fin effectiveness have been developed for the first time in literature via homotopy perturbation method. In this study, previous works have been extended to porous fins. Governing equations have been formulated by performing Darcy’s model. Dimensionless temperature distribution along the length of porous fin has been determined as a function of porosity and convection parameters. The ratio of porous fin to solid fin heat transfer rate has also been evaluated as a function of thermo-geometric fin parameter. The results have been compared with those of finite difference method for a specific case and an excellent agreement has been observed. The expressions developed are beneficial for thermal engineers for preliminary assessment of thermophysical systems instead of consuming time in heat conduction problems governed by strongly nonlinear differential equations

  16. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial

  17. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-01-01

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial.

  18. The Influence of Culture on the International Management of Shark Finning

    Dell'Apa, Andrea; Chad Smith, M.; Kaneshiro-Pineiro, Mahealani Y.

    2014-08-01

    Shark finning is prohibited in many countries, but high prices for fins from the Asian market help maintain the international black-market and poaching. Traditional shark fin bans fail to recognize that the main driver of fin exploitation is linked to cultural beliefs about sharks in traditional Chinese culture. Therefore, shark finning should be addressed considering the social science approach as part of the fishery management scheme. This paper investigates the cultural significance of sharks in traditional Chinese and Hawaiian cultures, as valuable examples of how specific differences in cultural beliefs can drive individuals' attitudes toward the property of shark finning. We suggest the use of a social science approach that can be useful in the design of successful education campaigns to help change individuals' attitudes toward shark fin consumption. Finally, alternative management strategies for commercial fishers are provided to maintain self-sustainability of local coastal communities.

  19. A Computational Fluid Dynamics (CFD) Analysis of an Undulatory Mechanical Fin Driven by Shape Memory Alloy

    Yong-Hua Zhang; Jian-Hui He; Jie Yang; Shi-Wu Zhang; Kin Huat Low

    2006-01-01

    Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy (SMA). The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured,grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin (amplitude, frequency and wavelength).

  20. PNS predictions for supersonic/hypersonic flows over finned missile configurations

    Bhutta, Bilal A.; Lewis, Clark H.

    1992-01-01

    Finned missile design entails accurate and computationally fast numerical techniques for predicting viscous flows over complex lifting configurations at small to moderate angles of attack and over Mach 3 to 15; these flows are often characterized by strong embedded shocks, so that numerical algorithms are also required to capture embedded shocks. The recent real-gas Flux Vector Splitting technique is here extended to investigate the Mach 3 flow over a typical finned missile configuration with/without side fin deflections. Elliptic grid-generation techniques for Mach 15 flows are shown to be inadequate for Mach 3 flows over finned configurations and need to be modified. Fin-deflection studies indicate that even small amounts of missile fin deflection can substantially modify vehicle aerodynamics. This 3D parabolized Navier-Stokes scheme is also extended into an efficient embedded algorithm for studying small axially separated flow regions due to strong fin and control surface deflections.

  1. A Novel Implementation of a Flexible Robotic Fin Actuated by Shape Memory Alloy

    Qin Yan; Lei Wang; Bo Liu; Jie Yang; Shiwu Zhang

    2012-01-01

    In this paper,study of a novel flexible robotic-fin actuated by Shape Memory Alloy (SMA) is presented.The developed robotic fin is capable of implementing various 3-Dimensional (3D) motions,which plays an important role in robot propulsion and maneuverability.Firstly,the morphological and mechanics parameters of a real pectoral fin from a carp are investigated.Secondly,a detailed design of the flexible pectoral fin driven by SMA is presented according to the previous morphological and mechanics analyses.Thirdly,a simplified theoretical model on the SMA fin plate is derived.The thermodynamics of the SMA plate and the relationship between curvature and phase transformation are analyzed.Finally,several simulations and model experiments are conducted according to the previous analyses.The results of the experiments are useful for the control of the robotic fin.The experimental results reveal that the SMA actuated fin ray has a good actuating performance.

  2. An improved model for predicting performance of finned tube heat exchanger under frosting condition, with frost thickness variation along fin

    Tso, C.P. [Multimedia University, Jalan Ayer Keroh Lama, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore (Singapore). School of Mechanical and Aerospace Engineering

    2006-01-15

    Frost accumulation on a heat exchanger, a direct result of combined heat and mass transfer between the moist air flowing across a cold surface, causes heat transfer performance degradation due to the insulating effect of frost layer and the coil blockage as the frost grows. The complex geometry of finned tube heat exchangers leads to uneven wall and air temperature distribution inside the coil, and causes variations of frost growth rate and densification along the coil. In this study, a general distributed model with frost formation was developed. The equations for finned tube heat exchanger were derived in non-steady-state manner and quasi-steady state in the frost model. In order to make the model more realistic, the variation of frost along fin due to uneven temperature distribution was included. The presented model is able to predict the dynamic behavior of an air cooler both under non-frost and frost condition. Comparisons were made based on the frost mass accumulation, pressure drop across coil and energy transfer coefficient, and results were found to agree well with reported experimental results. (author)

  3. The effects of perforation sizes on laminar heat transfer characteristics of an array of perforated fins

    Highlights: ► Thermal effects of perforation sizes and numbers are studied in perforated fins. ► Flow is laminar and perforations are along the length of fins. ► Porosity is defined as volume of perforations divided by volume of a solid fin. ► At a constant porosity, fins with fewer perforations have higher heat transfer rates. ► At a constant porosity, perforated fins do not affect total drag. - Abstract: Shaeri and Yaghoubi [25] reported the highest heat transfer rate in a laminar flow for a perforated fin with the most perforations (porosity), regardless of investigation on the effects of perforation sizes. In this study, the effects of size and number of perforations on laminar heat transfer characteristics of an array of perforated fins at the highest porosity of the study of Shaeri and Yaghoubi [25] have been numerically investigated. The Navier–Stokes and energy equations are solved by the finite volume procedure using the SIMPLE algorithm. Results show that at a specific porosity, the thermal entrance length of each perforation of a fin with a lower number of perforations is larger than that of each perforation of a fin with a higher number of perforations. Therefore, in a laminar flow and at a constant porosity, a fin with fewer perforations is more efficient to enhance the heat transfer rate compared with a fin with more perforations. Although perforated fins have higher friction drag and lower pressure drag with respect to solid fins, perforated fins do not affect total drag.

  4. Energetics of median and paired fin swimming, body and caudal fin swimming, and gait transition in parrotfish (Scarus schlegeli) and triggerfish (Rhinecanthus aculeatus)

    Korsmeyer, Keith E; Steffensen, John Fleng; Herskin, Jannik

    2002-01-01

    To determine the energetic costs of rigid-body, median or paired-fin (MPF) swimming versus undulatory, body-caudal fin (BCF) swimming, we measured oxygen consumption as a function of swimming speed in two MPF swimming specialists, Schlegel's parrotfish and Picasso triggerfish. The parrotfish swam...

  5. Co-Occurrence and Habitat Use of Fin Whales, Striped Dolphins and Atlantic Bluefin Tuna in the Northwestern Mediterranean Sea.

    Robert Klaus Bauer

    Full Text Available Different dolphin and tuna species have frequently been reported to aggregate in areas of high frontal activity, sometimes developing close multi-species associations to increase feeding success. Aerial surveys are a common tool to monitor the density and abundance of marine mammals, and have recently become a focus in the search for methods to provide fisheries-independent abundance indicators for tuna stock assessment. In this study, we present first density estimates corrected for availability bias of fin whales (Balaenoptera physalus and striped dolphins (Stenella coeruleoalba from the Golf of Lions (GoL, compared with uncorrected estimates of Atlantic bluefin tuna (ABFT; Thunnus thynnus densities from 8 years of line transect aerial surveys. The raw sighting data were further used to analyze patterns of spatial co-occurrence and density of these three top marine predators in this important feeding ground in the Northwestern Mediterranean Sea. These patterns were investigated regarding known species-specific feeding preferences and environmental characteristics (i. e. mesoscale activity of the survey zone. ABFT was by far the most abundant species during the surveys in terms of schools and individuals, followed by striped dolphins and fin whales. However, when accounted for availability bias, schools of dolphins and fin whales were of equal density. Direct interactions of the species appeared to be the exception, but results indicate that densities, presence and core sighting locations of striped dolphins and ABFT were correlated. Core sighting areas of these species were located close to an area of high mesoscale activity (oceanic fronts and eddies. Fin whales did not show such a correlation. The results further highlight the feasibility to coordinate research efforts to explore the behaviour and abundance of the investigated species, as demanded by the Marine Strategy Framework Directive (MSFD.

  6. Co-Occurrence and Habitat Use of Fin Whales, Striped Dolphins and Atlantic Bluefin Tuna in the Northwestern Mediterranean Sea.

    Bauer, Robert Klaus; Fromentin, Jean-Marc; Demarcq, Hervé; Brisset, Blandine; Bonhommeau, Sylvain

    2015-01-01

    Different dolphin and tuna species have frequently been reported to aggregate in areas of high frontal activity, sometimes developing close multi-species associations to increase feeding success. Aerial surveys are a common tool to monitor the density and abundance of marine mammals, and have recently become a focus in the search for methods to provide fisheries-independent abundance indicators for tuna stock assessment. In this study, we present first density estimates corrected for availability bias of fin whales (Balaenoptera physalus) and striped dolphins (Stenella coeruleoalba) from the Golf of Lions (GoL), compared with uncorrected estimates of Atlantic bluefin tuna (ABFT; Thunnus thynnus) densities from 8 years of line transect aerial surveys. The raw sighting data were further used to analyze patterns of spatial co-occurrence and density of these three top marine predators in this important feeding ground in the Northwestern Mediterranean Sea. These patterns were investigated regarding known species-specific feeding preferences and environmental characteristics (i. e. mesoscale activity) of the survey zone. ABFT was by far the most abundant species during the surveys in terms of schools and individuals, followed by striped dolphins and fin whales. However, when accounted for availability bias, schools of dolphins and fin whales were of equal density. Direct interactions of the species appeared to be the exception, but results indicate that densities, presence and core sighting locations of striped dolphins and ABFT were correlated. Core sighting areas of these species were located close to an area of high mesoscale activity (oceanic fronts and eddies). Fin whales did not show such a correlation. The results further highlight the feasibility to coordinate research efforts to explore the behaviour and abundance of the investigated species, as demanded by the Marine Strategy Framework Directive (MSFD). PMID:26458254

  7. Alterations in Body Fluid Balance During Fin Swimming in 29 °C Water in a Population of Special Forces Divers.

    Castagna, O; Desruelle, A V; Blatteau, J E; Schmid, B; Dumoulin, G; Regnard, J

    2015-12-01

    Highly trained "combat swimmers" encounter physiological difficulties when performing missions in warm water. The aim of this study was to assess the respective roles of immersion and physical activity in perturbing fluid balance of military divers on duty in warm water. 12 trained divers performed 2 dives each (2 h, 3 m depth) in fresh water at 29 °C. Divers either remained Static or swam continuously (Fin) during the dive. In the Fin condition, oxygen consumption and heart rate were 2-fold greater than during the Static dive. Core and skin temperatures were also higher (Fin: 38.5±0.4 °C and 36.2±0.3 °C and Static: 37.2±0.3 °C and 34.3±0.3 °C; respectively p=0.0002 and p=0.0003). During the Fin dive, the average mass loss was 989 g (39% urine loss, 41% sweating and 20% insensible water loss and blood sampling); Static divers lost 720 g (84% urine loss, 2% sweating and 14% insensible water loss and blood sampling) (p=0.003). In the Fin condition, a greater decrease in total body mass and greater sweating occurred, without effects on circulating renin and aldosterone concentrations; diuresis was reduced, and plasma volume decreased more than in the Static condition. PMID:26422054

  8. Optimization of “T”-Shaped Fins Geometry Using Constructal Theory and “FEA” Concepts

    ManasRanjanPadhy

    2014-12-01

    Full Text Available This paper reports the geometric (constructal optimization of T-shaped fin assemblies, where the objective is to maximize the global thermal conductance of the assembly, subject to total volume and fin-material constraints. Assemblies of plate fins are considered. It is shown that every geometric feature of the assembly is delivered by the optimization principle and the constraints. These optimal features are reported in dimensionless terms for this entire class of fin assemblies. Based on the constructal theory by Dr. A Bejan, T-shaped fins are developed for better heat conductance as compared to conventional fins. Now the geometry of this T type of fin contains many geometry parameters which affect the overall conductance of the fin. With the same material constraint and volume constraints optimal geometry ratios has been calculated so as to design the fin for its best performance. With focus to the practical situations and heat flow patterns, it is quite complex to calculate the temperatures on a T-shaped fin. It requires the help of FEA concepts and CAE software to optimize the geometry.

  9. Pectoral fin morphology of batoid fishes (Chondrichthyes: Batoidea): explaining phylogenetic variation with geometric morphometrics.

    Franklin, Oliver; Palmer, Colin; Dyke, Gareth

    2014-10-01

    The diverse cartilaginous fish lineage, Batoidea (rays, skates, and allies), sister taxon to sharks, comprises a huge range of morphological diversity which to date remains unquantified and unexplained in terms of evolution or locomotor style. A recent molecular phylogeny has enabled us to confidently assess broadscale aspects of morphology across Batoidea. Geometric morphometrics quantifies the major aspects of shape variation, focusing on the enlarged pectoral fins which characterize batoids, to explore relationships between ancestry, locomotion and habitat. A database of 253 specimens, encompassing 60 of the 72 batoid genera, reveals that the majority of morphological variation across Batoidea is attributable to fin aspect-ratio and the chordwise location of fin apexes. Both aspect-ratio and apex location exhibit significant phylogenetic signal. Standardized independent linear contrast analysis reveals that fin aspect-ratio can predict locomotor style. This study provides the first evidence that low aspect-ratio fins are correlated with undulatory-style locomotion in batoids, whereas high aspect-ratio fins are correlated with oscillatory locomotion. We also show that it is phylogeny that determines locomotor style. In addition, body- and caudal fin-locomotors are shown to exhibit low aspect-ratio fins, whereas a pelagic lifestyle correlates with high aspect-ratio fins. These results emphasize the importance of phylogeny in determining batoid pectoral fin shape, however, interactions with other constraints, most notably locomotor style, are also highlighted as significant. PMID:24797832

  10. Optimal design of plate-fin heat exchangers by a Bees Algorithm

    In this study, the application of Bees Algorithm (BA) in the optimum design of a cross flow plate-fin heat exchanger with offset strip fin is investigated. First, heat exchanger is optimized and designed according to the effectiveness optimization. Then, an analysis based on the second law of thermodynamics and minimizations of entropy generation units is performed. Specific heat duty, space restriction and permitted pressure drop are considered as the constraints for maximizing the effectiveness and minimizing the entropy generation units. Hot and cold flow length of the heat exchangers, number of fin layers, fin frequency, fin height, fin strip length and fin thickness are introduced as optimization variables. The effectiveness and accuracy of the suggested algorithm are compared with literature. The results have shown that BA can find optimum configuration with higher accuracy in comparison with Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Imperialist Competitive Algorithm (ICA) and preliminary design. - Highlights: •We analyzed a plate-fin heat exchanger with offset strip fins. •This is the first application of a Bees Algorithm for plate-fin heat exchanger design. •Preliminarily design and effectiveness of PFHE was improved by minimizing the entropy generation units. •The results show the superiority of this method over GA, PSO and ICA and preliminary design

  11. N. meningitidis 1681 is a member of the FinO family of RNA chaperones.

    Chaulk, S.; Lu, J.; Tan, K.; Arthur, D.; Edwards, R.; Frost, L.; Joachimiak, A.; Glover, J. (Biosciences Division); (Univ. of Alberta)

    2010-11-01

    The conjugative transfer of F-like plasmids between bacteria is regulated by the plasmid-encoded RNA chaperone, FinO, which facilitates sense - antisense RNA interactions to regulate plasmid gene expression. FinO was thought to adopt a unique structure, however many putative homologs have been identified in microbial genomes and are considered members of the FinO-conjugation-repressor superfamily. We were interested in determining whether other members were also able to bind RNA and promote duplex formation, suggesting that this motif does indeed identify a putative RNA chaperone. We determined the crystal structure of the N. meningitidis MC58 protein NMB1681. It revealed striking similarity to FinO, with a conserved fold and a large, positively charged surface that could function in RNA interactions. Using assays developed to study FinO-FinP sRNA interactions, NMB1681, like FinO, bound tightly to FinP RNA stem-loops with short 5-foot and 3-foot single-stranded tails but not to ssRNA. It also was able to catalyze strand exchange between an RNA duplex and a complementary single-strand, and facilitated duplexing between complementary RNA hairpins. Finally, NMB1681 was able to rescue a finO deficiency and repress F plasmid conjugation. This study strongly suggests that NMB1681 is a FinO-like RNA chaperone that likely regulates gene expression through RNA-based mechanisms in N. meningitidis.

  12. Patterning challenges in advanced device architectures: FinFETs to nanowires

    Horiguchi, N.; Milenin, A. P.; Tao, Z.; Hubert, H.; Altamirano-Sanchez, E.; Veloso, A.; Witters, L.; Waldron, N.; Ragnarsson, L.-Å.; Kim, M. S.; Kikuchi, Y.; Mertens, H.; Raghavan, P.; Piumi, D.; Collaert, N.; Barla, K.; Thean, A. V.

    2016-03-01

    Si FinFET scaling is getting more difficult due to extremely narrow fin width control and power dissipation. Nanowire FETs and high mobility channel are attractive options for CMOS scaling. Nanowire FETs can maintain good electrostatics with relaxed nanowire diameter. High mobility channel can provide good performance at low power operation. However their fin patterning is challenging due to fins consisted of different materials or fragile high mobility material. Controlled etch and strip are necessary for good fin cd and profile control. Fin height increase is a general trend of scaled FinFETs and nanowire FETs, which makes patterning difficult not only in fin, but also in gate, spacer and replacement metal gate. It is important that gate and spacer etch have high selectivity to fins and good cd and profile control even with high aspect ratio of fin and gate. Work function metal gate patterning in scaled replacement metal gate module needs controlled isotropic etch without damaging gate dielectric. SF6 based etch provides sharp N-P boundary and improved gate reliability.

  13. Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

    Junqi DONG; Jiangping CHEN; Zhijiu CHEN

    2008-01-01

    Experimental studies were conducted to investigate the air-side heat transfer and pressure drop characteristics of a novel louvered fins and flat tube heat exchangers. A series of tests were conducted for 9 heat exchangers with different fin space and fin length, at a constant tube-side water flow rate of 2.8 m/h. The air side thermal performance data were analyzed using the effectiveness-NTU method. Results were presented as plot of Colburn j factor and friction factor f against the Reynolds number in the range of 500-6500. The characteristics of the heat transfer and pressure drop of different fin space and fin length were analyzed and compared. In addition, the curves of the heat transfer coefficients vs. pumping power per unit heat transfer area were plotted. Finally, the area optimization factor was used to evaluate the thermal hydraulic performance of the louvered fins with differential geometries. The results showed that the j and ffactors increase with the decrease of the fin space and fin length, and the fin space has more obvious effect on the thermal hydraulic characteristics of the novel louvered fins.

  14. Application of homotopy analysis method and inverse solution of a rectangular wet fin

    Highlights: • Solution of a wet fin with is obtained by homotopy analysis method (HAM). • Present HAM results have been well-validated with literature results. • Inverse analysis is done using genetic algorithm. • Measurement error of ±10–12% (approx.) is found to yield satisfactory reconstructions. - Abstract: This paper presents the analytical solution of a rectangular fin under the simultaneous heat and mass transfer across the fin surface and the fin tip, and estimates the unknown thermal and geometrical configurations of the fin using inverse heat transfer analysis. The local temperature field is obtained by using homotopy analysis method for insulated and convective fin tip boundary conditions. Using genetic algorithm, the thermal and geometrical parameters, viz., thermal conductivity of the material, surface heat transfer coefficient and dimensions of the fin have been simultaneously estimated for the prescribed temperature field. Earlier inverse studies on wet fin have been restricted to the analysis of nonlinear governing equation with either insulated tip condition or finite tip temperature only. The present study developed a closed-form solution with the consideration of nonlinearity effects in both governing equation and boundary condition. The study on inverse optimization leads to many feasible combination of fin materials, thermal conditions and fin dimensions. Thus allows the flexibility for designing a fin under wet conditions, based on multiple combinations of fin materials, fin dimensions and thermal configurations to achieve the required heat transfer duty. It is further determined that the allowable measurement error should be limited to ±10–12% in order to achieve satisfactory reconstruction

  15. New developments in compact plate-fin heat exchangers

    The extension of compact plate-fin heat exchanger capabilities in order to accommodate the performance requirements of regeneratively cooled hypersonic ramjet engines, laser weapons, aircraft engine infrared suppressors, and large high-efficiency gas turbine cycles is described. Attention is given to cooling fluid flow path geometry and heat exchanger fabrication techniques, such novel materials as alumina and silicon carbide, and space and weight constraints imposed on designs by airborne application. It is shown that operating temperatures, pressures and area densities have been significantly increased

  16. Het fin-de-siècle als vertoning

    W. Krul

    2002-01-01

    Full Text Available

    1900

    Wessel Krul
    In their publication entitled 1900: Hoogtij van burgerlijke cultuur, the authors, Jan Bank and Maarten van Buuren, failed to pay adequate attention to the contrasts and differences that typified Dutch culture at the fin de siècle. The book therefore lacks analytical precision. The term 'bourgeois culture' should not have been applied in such an all-inclusive and unambiguous manner.

  17. Transfer coefficients for plate fin and elliptical tube heat exchangers

    In order to determine transfer coefficients for plate fin and elliptical tube exchangers, mass transfer experiments have been performed using the naphthalene sublimation technique. By means of the heat-mass transfer analogy, the results can be converted to heat transfer results. The transfer coefficients were compared with those for circular tube exchangers and the comparison revealed no major differences. This is a positive outcome, since the use of elliptical tubes may reduce substantially the pressure drop, without affecting the transfer characteristics.(Author)

  18. Markkinointiviestintäsuunnitelma : Air D Fin Oy

    Häkkinen, Susanna; Laakkonen, Niko

    2013-01-01

    Opinnäytetyömme aiheena oli markkinointiviestinnän suunnitelman tekeminen pienelle toimintansa alkuvaiheessa olevalle perheyritykselle, Air D Fin Oy:lle. Tutkimuskysymyksenämme oli selvittää mitkä ovat pk-yrityksen yksityisasiakkaille suunnatun markkinointiviestinnän tärkeimmät keinot ja välineet. Lisäksi tavoitteena oli löytää tutkimuksen avulla AirD:n yksityisasiakkaiden asiakasprofiili ja selvittää kuluttajien kiinnostus tuotetta kohtaan. AirD on eteläsuomalainen perheyritys, joka on p...

  19. Coning motion stability of wrap around fin rockets

    2007-01-01

    Both the asymptotical stability criterion and the bounded stability criterion of the coning motion for wrap around fin(WAF) rockets are proposed through the analy-sis of coning motion equations,which can be easily used to determine the exis-tence of the coning motion during the rocket design. The correctness of the crite-rions is verified by mathematical simulation examples of a WAF rocket with differ-ent setting angles. It is also found that the setting angle of WAF has great effects on the rolling moment and side moment of the rocket.

  20. Coning motion stability of wrap around fin rockets

    MAO XueRui; YANG ShuXing; XU Yong

    2007-01-01

    Both the asymptotical stability criterion and the bounded stability criterion of the coning motion for wrap around fin (WAF) rockets are proposed through the analysis of coning motion equations, which can be easily used to determine the existence of the coning motion during the rocket design. The correctness of the criterions is verified by mathematical simulation examples of a WAF rocket with different setting angles. It is also found that the setting angle of WAF has great effects on the rolling moment and side moment of the rocket.

  1. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    Stolecki M.; Bijok H.; Kowal Ł.; Adamiec J.

    2015-01-01

    This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, ...

  2. Numerical Appraisal of Heat Transfer and Flow in Concentric Annuli Permeable and Impermeable Fins by using Nanofluids

    Dr. Khalid Faisal Sultan

    2014-01-01

    Numerical study was carried out to investigate the natural convection heat transfer enhancement by using utilizing various nanofluids in a three – dimensional annulus. The annulus between two concentric cylinders with porous (permeable)fins , solid (impermeable) fins, without fins and these fins attached to the inner cylinder. The inner cylinder and two fins are maintained at constant wall temperature (CWT),while the outer cylinder is diathermal (adiabatic).The problem was solved ...

  3. Analytical solution of non-Fourier heat conduction problem on a fin under periodic boundary conditions

    Ahmadikia, H. [University of Isfahan, Isfahan (Iran, Islamic Republic of); Rismanian, M. [Bu-Ali Sina University, Hamadan (Iran, Islamic Republic of)

    2011-11-15

    Fourier and hyperbolic models of heat transfer on a fin that is subjected to a periodic boundary condition are solved analytically. The differential equation in Fourier and non-Fourier models is solved by the Laplace transform method. The temperature distribution on the fin is obtained using the residual theorem in a complex plan for the inverse Laplace transform method. The thermal shock is generated at the base of the fin, which moves toward the tip of the fin and is reflected from the tip. The current study of various parameters on the thermal shock location shows that relaxation time has a great influence on the temperature distribution on the fin. An unsteady boundary condition in the base fin caused the shock, which is generated continuously from the base and has interacted with the other reflected thermal shocks. Results of the current study show that the hyperbolic heat conduction equation can violate the second thermodynamic law under some unsteady boundary conditions.

  4. Analytical solution of non-Fourier heat conduction problem on a fin under periodic boundary conditions

    Fourier and hyperbolic models of heat transfer on a fin that is subjected to a periodic boundary condition are solved analytically. The differential equation in Fourier and non-Fourier models is solved by the Laplace transform method. The temperature distribution on the fin is obtained using the residual theorem in a complex plan for the inverse Laplace transform method. The thermal shock is generated at the base of the fin, which moves toward the tip of the fin and is reflected from the tip. The current study of various parameters on the thermal shock location shows that relaxation time has a great influence on the temperature distribution on the fin. An unsteady boundary condition in the base fin caused the shock, which is generated continuously from the base and has interacted with the other reflected thermal shocks. Results of the current study show that the hyperbolic heat conduction equation can violate the second thermodynamic law under some unsteady boundary conditions

  5. Forced convection heat transfer correlation for finned plates in a duct

    Forced convection heat transfer experiments were conducted for plate-fin in a duct using various fin spacing, fin height, duct width, Reynolds number for Prandtl numbers 2,014. Based upon analogy concept, mass transfer rate were measured instead of heat transfer rates. The heat transfer rates were enhanced with the increase of fin height and decrease of fin spacing as they increase the heat transfer area. Meanwhile, heat transfer rates were impaired with the increase of the duct width as the bypass flows increased to tip clearance region. Forced convection heat transfer correlations were developed for laminar and turbulent flow conditions and for narrow and wide ducts. The work draws attention to the tip clearance on the heat transfer of the finned plate in a duct. (author)

  6. One Dimensional Finite Element Analysis of Heat Dissipation from Rectangular Fin with Longitudinal Hexagonal Perforations

    Isam H. E. Qasem

    2015-06-01

    Full Text Available In this study the finite element method (FEM is used in solving the heat dissipation from a perforated fin. This fin is horizontal rectangular fin subjected to natural convection and provided with longitudinal hexagonal perforations. The orientation of these perforations is described as they have two sides parallel to the fin sides. The body of the fin is discretized into the sufficient finite elements. The number of these elements can be altered as required according to the automatic mesh generation. The heat dissipation of the perforated fin is computed and compared with that of the solid one of the same dimensions and same thermal properties. The comparison refers to acceptable results and heat dissipation enhancement due to certain perforation.

  7. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Reid, D. R.; Taborek, J.

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded 'plain' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of 'segmented' fins. The main advantage of this fin design is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  8. De la fin de la guerre froide au début de la guerre sans fin

    Ferrier, Jean Pierre

    2006-01-01

    El Profesor Ferrier nos describe los acontecimientos de la sociedad internacional en los ultimos 15 años y señala la profunda diferencia entre "la estabilidad" durante la guerra fría y la "revolucion" que se ha producido en el escenario internacional a partir de la caida del muro de Berlin. Hace especial referencia al comportamiento de la superpotencia (Estados Unidos) y su guerra sin fin contra los "nuevos enemigos" en los diferentes teatros internacionales en su lucha por imponer el "Bien" ...

  9. Experimental investigation of water sprayed finned heat exchanger tube bundles

    Experimental investigations have been made to study the performance of two finned tube-bundle heat exchangers (FORGO type) when wetted by water sprays. The heat exchangers are designed to cool water in a dry cooling tower. The test-elements had a frontal area of 1 m2. The water sprays were created by 20 nozzles, 200 mm in front of the heat exchangers. Air velocities at the inlet of the coolers were in the range 0,8 m/s to 12 m/s and initial temperature differences ITD reached 45 degrees C. The test facility was designed to determine the combined latent and sensible heat fluxes in the wetted heat exchanger, the airside pressure drop and the air humidity and temperature at the exchanger inlet and outlet, and to measure the weight of the water wetting the cooler's surface. The sprayed test elements were investigated in different positions, but most of the experiments were carried out in the position with the fins horizontal

  10. Natural Convection in a Finned Rayleigh-Benard Cubical Enclosure

    The papers deals with a numerical 3D study of natural convection in a finned Rayleigh-Be nard (RB) cubical enclosure. A single fin with a thickness of 10 pour cent of the cavity side (and a height of 50 pour cent ) is placed vertically on the bottom hot wall at TH. The working fluid is air with Prandtl number Pr = 0.71 and the Rayleigh number (Ra) varies from 103 to 105. The solid-to-fluid thermal conductivity ratio (kR) was fixed at RK = 7000, corresponding to a metal of high conductivity. The top wall is at the temperature TC H and the remaining four surfaces are insulated. Inside the RB enclosure, the flow structure and the temperature distribution are presented in terms of mean velocity vector plots and isotherm plots. The effects of the Rayleigh number on the mean heat transfer rate through the cold wall are presented and discussed. A correlation between the averaged Nusselt number through the top wall and Ra is proposed

  11. Lionfish predators use flared fin displays to initiate cooperative hunting.

    Lönnstedt, Oona M; Ferrari, Maud C O; Chivers, Douglas P

    2014-06-01

    Despite considerable study, mystery surrounds the use of signals that initiate cooperative hunting in animals. Using a labyrinth test chamber, we examined whether a lionfish, Dendrochirus zebra, would initiate cooperative hunts with piscine partners. We found that D. zebra uses a stereotyped flared fin display to alert conspecific and heterospecific lionfish species Pterois antennata to the presence of prey. Per capita success rate was significantly higher for cooperative hunters when compared with solitary ones, with hunt responders assisting hunt initiators in cornering the prey using their large extended pectoral fins. The initiators would most often take the first strike at the group of prey, but both hunters would then alternate striking at the remaining prey. Results suggest that the cooperative communication signal may be characteristic to the lionfish family, as interspecific hunters were equally coordinated and successful as intraspecific hunters. Our findings emphasize the complexity of collaborative foraging behaviours in lionfish; the turn-taking in strikes suggests that individuals do not solely try to maximize their own hunting success: instead they equally share the resources between themselves. Communicative group hunting has enabled Pteroine fish to function as highly efficient predators. PMID:24966203

  12. Analysis of natural convective heat transfer of nano coated aluminium fins using Taguchi method

    Senthilkumar, R.; Nandhakumar, A. J. D.; Prabhu, S.

    2013-01-01

    Rectangular aluminium fins were preferred for analysis and coated by carbon nano tubes using PVD to enhance the heat transfer rate of fins. Convective heat transfer rates for coated and non-coated surfaces were calculated and compared. The temperature and heat transfer characteristics were investigated using Nusselt, Grashof, Prandtl and Rayleigh numbers and also optimized by Taguchi method and ANOVA analysis. The average percentage of increase in fin efficiency is 5 %.

  13. Flow structure of natural dehumidification over a horizontal finned-tube

    Hirbodi, Kamran; Yaghoubi, Mahmood

    2015-08-01

    In the present study, structure of water drops formation, growth, coalescence and departure over a horizontal finned-tube during natural dehumidification is investigated experimentally. Starting time of repelling the drops as well as heat transfer rate and the rate of dripping condensates in quasi-steady-state conditions are presented. Furthermore, cold airflow pattern around the horizontal finned-tube is visualized by using smoke generation scheme during natural dehumidification process. The finned-tube has a length of 300 mm, and inner and outer fin diameters, fin thickness and fin spacing are 25.4, 56, 0.4 and 2 mm, respectively. The tests are conducted in an insulated control room with dimensions of 5.8 m × 3 m × 4 m. Ambient air temperature, relative humidity and fin base temperature are selected from 25 to 35 °C, from 40 to 70 % and from 4 to 8 °C, respectively. Observations show that natural condensation from humid air over the test case is completely dropwise. Droplets only form on the edge of the fin and lateral fin surfaces remain almost dry. Dehumidification process over the tested finned-tube is divided into four stages; nucleation, formation, growth and departure of drops. It is also observed that the condensate inundation leaves the tube bottom in the form of droplets. Smoke visualization depicts that humid airflows downward around the cold finned-tube surface without noticeable turbulence and separation in the initial stages of dehumidification process. But the airflow has some disturbances in the intermediate stage and especially during drop departure on the edge of the fins.

  14. Oscillatory Adaptive Yaw-Plane Control of Biorobotic Autonomous Underwater Vehicles Using Pectoral-Like Fins

    Mugdha S. Naik; Sahjendra N. Singh

    2007-01-01

    This article considers the control of a biorobotic autonomous underwater vehicle (BAUV) in the yaw plane using biologically inspired oscillatory pectoral-like fins of marine animals. The fins are assumed to be oscillating harmonically with a combined linear (sway) and angular (yaw) motion producing unsteady forces, which are used for fish-like control of BAUVs. Manoeuvring of the BAUV in the yaw plane is accomplished by altering the bias (mean) angle of the angular motion of the fin. For the ...

  15. 3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

    FAROUK TAHROUR; ABDELMOUMENE HAKIM BENMACHICHE; MOUNIR AKSAS; CHERIF BOUGRIOU

    2015-01-01

    The use of 3-D computational fluid dynamics (CFD) is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, th...

  16. Automated Identification of Individual Great White Sharks from Unrestricted Fin Imagery

    Hughes, Benjamin J; Burghardt, Tilo

    2015-01-01

    The objective of this paper is automatically to identify individual great white sharks in a database of thousands of unconstrained fin images. The approach put forward appreciates shark fins in natural imagery as smooth, flexible and partially occluded objects with an individuality encoding trailing edge. In order to recover animal identities therefrom. We first introduce an open contour stroke model which extends multi-scale region segmentation to achieve robust fin detection. Secondly, we s...

  17. Simulation study of a 3-D device integrating FinFET and UTBFET

    Fahad, Hossain M.

    2015-01-01

    By integrating 3-D nonplanar fins and 2-D ultrathin bodies, wavy FinFETs merge two formerly competing technologies on a silicon-on-insulator platform to deliver enhanced transistor performance compared with conventional trigate FinFETs with unprecedented levels of chip-area efficiency. This makes it suitable for ultralarge-scale integration high-performance logic at and beyond the 10-nm technology node.

  18. Blue and fin whale call source levels and propagation range in the Southern Ocean

    Sirovic, Anna; Hildebrand, John A.; Wiggins, Sean

    2007-01-01

    Blue (Balaenoptera musculus) and fin whales (B. physalus) produce high-intensity, low-frequency calls, which probably function for communication during mating and feeding. The source levels of blue and fin whale calls off the Western Antarctic Peninsula were calculated using recordings made with calibrated, bottom-moored hydrophones. Blue whales were located up to a range of 200 km using hyperbolic localization and time difference of arrival. The distance to fin whales, estimated using multi...

  19. Temperature-Sensitive Mutations That Cause Stage-Specific Defects in Zebrafish Fin Regeneration

    Johnson, S. L.; Weston, J A

    1995-01-01

    When amputated, the fins of adult zebrafish rapidly regenerate the missing tissue. Fin regeneration proceeds through several stages, including wound healing, establishment of the wound epithelium, recruitment of the blastema from mesenchymal cells underlying the wound epithelium, and differentiation and outgrowth of the regenerate. We screened for temperature-sensitive mutations that affect the regeneration of the fin. Seven mutations were identified, including five that fail to regenerate th...

  20. Nonlinear flutter wind tunnel test and numerical analysis of folding fins with freeplay nonlinearities

    Yang Ning; Wang Nan; Zhang Xin; Liu Wei

    2016-01-01

    The flutter characteristics of folding control fins with freeplay are investigated by numerical simulation and flutter wind tunnel tests. Based on the characteristics of the structures, fins with different freeplay angles are designed. For a 0° angle of attack, wind tunnel tests of these fins are conducted, and vibration is observed by accelerometers and a high-speed camera. By the expansion of the connected relationships, the governing equations of fit for the nonlinear aeroelastic analysis ...

  1. Boxfishes (Teleostei: Ostraciidae) as a model system for fishes swimming with many fins: kinematics

    Hove, J. R.; O'Bryan, L. M.; Gordon, M.S.; Webb, P. W.; Weihs, D.

    2001-01-01

    Swimming movements in boxfishes were much more complex and varied than classical descriptions indicated. At low to moderate rectilinear swimming speeds (5 TL s^(-1)) was characterized by the use of a caudal burst-and-coast variant. Adduction was always faster than abduction in the pectoral fins. There were no measurable refractory periods between successive phases of the fin movement cycles. Dorsal and anal fin movements were synchronized at speeds greater than 2.5 ...

  2. Is caudal fin colour in tigerfish Hydrocynus vittatus a sex or population trait?

    Soekoe, M.; F. H. van der Bank; Smit, N.J.

    2013-01-01

    Tigerfish caudal fin colours vary from yellow to red, with distinct dissimilarities previously noted. To understand these colour differences, tigerfish were collected during 2008 to 2010 from four southern African populations in the Upper Zambezi River (ZAM), Okavango Delta (OKA), Pongolapoort Dam (POD) and Phongolo River (POR), and caudal fin colouration was classified according to pattern and sex. Muscle and liver tissue were assayed by starch electrophoresis. Caudal fin colour in OKA, ZAM ...

  3. Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method

    Ningyu Li; Yumin Su

    2016-01-01

    Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB) method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin...

  4. Predicting propulsive forces using distributed sensors in a compliant, high DOF, robotic fin.

    Kahn, Jeff C; Peretz, David J; Tangorra, James L

    2015-06-01

    Engineered robotic fins have adapted principles of propulsion from bony-finned fish, using spatially-varying compliance and complex kinematics to produce and control the fin's propulsive force through time. While methods of force production are well understood, few models exist to predict the propulsive forces of a compliant, high degree of freedom, robotic fin as it moves through fluid. Inspired by evidence that the bluegill sunfish (Lepomis macrochirus) has bending sensation in its pectoral fins, the objective of this study is to understand how sensors distributed within a compliant robotic fin can be used to estimate and predict the fin's propulsive force. A biorobotic model of a bluegill sunfish pectoral fin was instrumented with pressure and bending sensors at multiple locations. Experiments with the robotic fin were executed that varied the swimming gait, flapping frequency, stroke phase, and fin stiffness to understand the forces and sensory measures that occur during swimming. A convolution-based, multi-input-single-output (MISO) model was selected to model and study the relationships between sensory data and propulsive force. Subsets of sensory data were studied to determine which sensor modalities and sensor placement locations resulted in the best force predictions. The propulsive forces of the fin were accurately predicted using the linear MISO model on intrinsic sensory data. Bending sensation was more effective than pressure sensation for predicting propulsive forces, and the importance of bending sensation was consistent with several results in biology and engineering studies. It was important to have a spatial distribution of sensors and multiple sensory modalities in order to predict forces across large changes to dynamics. The relationship between propulsive forces and intrinsic sensory measures is complex, and good models should allow for temporal lags between forces and sensory data, changes to the model within a fin stroke, and changes to the

  5. Cultural identities of Chinese business : networks of the shark-fin business in Hong Kong.

    Gordon C. K. Cheung; Chang, Chak Yan

    2011-01-01

    From a global standard, shark-fin consumption certainly violates international norms on bio-diversity and endangers the existence of the shark species. Furthermore, the commercial shark-fin industry generates additional adverse environmental impacts. Nevertheless, shark-fin consumption has served an important role in the cultural aspect of Chinese ‘foodway’. More importantly, the business relations and networks behind this industry have never been comprehensively studied. In so doing, this pa...

  6. Flow structure of natural dehumidification over a horizontal finned-tube

    Hirbodi, Kamran; Yaghoubi, Mahmood

    2016-08-01

    In the present study, structure of water drops formation, growth, coalescence and departure over a horizontal finned-tube during natural dehumidification is investigated experimentally. Starting time of repelling the drops as well as heat transfer rate and the rate of dripping condensates in quasi-steady-state conditions are presented. Furthermore, cold airflow pattern around the horizontal finned-tube is visualized by using smoke generation scheme during natural dehumidification process. The finned-tube has a length of 300 mm, and inner and outer fin diameters, fin thickness and fin spacing are 25.4, 56, 0.4 and 2 mm, respectively. The tests are conducted in an insulated control room with dimensions of 5.8 m × 3 m × 4 m. Ambient air temperature, relative humidity and fin base temperature are selected from 25 to 35 °C, from 40 to 70 % and from 4 to 8 °C, respectively. Observations show that natural condensation from humid air over the test case is completely dropwise. Droplets only form on the edge of the fin and lateral fin surfaces remain almost dry. Dehumidification process over the tested finned-tube is divided into four stages; nucleation, formation, growth and departure of drops. It is also observed that the condensate inundation leaves the tube bottom in the form of droplets. Smoke visualization depicts that humid airflows downward around the cold finned-tube surface without noticeable turbulence and separation in the initial stages of dehumidification process. But the airflow has some disturbances in the intermediate stage and especially during drop departure on the edge of the fins.

  7. A Study of the Twin Fin Concept for Cruise Ship Applications

    Nyström, Frida

    2015-01-01

    The aim with this thesis is to investigate if the Twin Fin concept can be a beneficial propulsion system for large cruise ships, about 300 m long. The Twin Fin concept is a new propulsion system, launched in 2014 by Caterpillar Propulsion [1]. The concept is diesel-electric and has two fins, containing a gearbox and an electric motor, immersed in water [2]. Previous investigations have shown the concept to have several advantages compared to other propulsion systems . A seismic vessel, Polarc...

  8. Thermal performance of a porus radial fin with natural convection and radiative heat losses

    Darvishi M.T.

    2015-01-01

    Full Text Available An analytic (series solution is developed to describe the thermal performance of a porous radial fin with natural convection in the fluid saturating the fin and radiation heat loss from the top and bottom surfaces of the fin. The HAM results for the temperature distribution and base heat flux are compared with the direct numerical results and found to be very accurate.

  9. The impact of fin profile and interface condition on performance characteristics of heat sinks

    Thermal management of electronic products relies mainly on the effective dissipation of heat. Heat sinks (containing multiple extended surfaces or fin array) are commonly used for heat dissipation network. The performance of an individual fin depends on its geometry, material properties and operating environment (i.e. free or forced convection). In the first part of this paper, the four most commonly used fin profiles are studied for pin, longitudinal and annular fins using non-dimensional finite element formulation. In the second part, the performance of different thermal interfaces is studied for polymer and metallic fins. Polymer composite materials result in significant increase in the performance of a fin; however manufacturing can be a constraint to construct an effective heat sink due to interface conditions at the fin and base plate junction. It is found that the joint at fin base plate has considerable stress effect in the heat sink system. The press fit joint must have high contact pressure to maintain an appropriate thermal contact conductance (TCC) in order to have thermal performance comparable to an adhesive joint, but the two joints have different state of thermal and contact stresses. -- Highlights: ► The effect of fin profile on performance for pin, longitudinal and annular fins is studied. ► The significant effect is found only for pin fins under considered conditions. ► The effect of interface at orthotropic pin fin and metallic base plate is studied. ► Two interface conditions called epoxy-bonded and press-fitted are studied. ► The contact pressure and stresses decrease at high temperature for press-fitted interface

  10. Plate-fin array cooling using a finger-like piezoelectric fan

    In this study, the heat transfer of a plate-fin array cooled by a vibrating finger-like piezoelectric fan comprising four flexible rectangular blades was investigated. The results indicated that the heat transfer enhancement of the fin array cooled by a vibrating piezoelectric fan at x/L = 0.5 and H = 5 mm ranged between 1.5 and 3.3, regardless of the fin array orientation. However, the heat transfer enhancement caused by a fan being placed at either edge of the fin array yielded a dissimilar result between both of the fin array orientations because of the superimposed effects of the boundary layer development and the air flow induced by the fan. This dissimilarity was especially noticeable when the piezoelectric fan was composed of aluminum blades to accommodate the moderate Reynolds number. In addition to the Reynolds number, the ratio of the fan blade vibration envelope to the source area determined the Nu number of the piezoelectric fan-cooled fin array. This design enhanced the fin array heat transfer and reduced cooler volume by embedding multiple vibrating beams into the fin array. -- Highlights: • Heat transfer of a piezoelectric fan-cooled plate-fin array was investigated. • Effects of fan position, fan height and fan material on heat transfer were examined. • Similar heat transfer enhancement range was shown for both fin array orientations. • Fin heat transfer with a running Al fan at x = 0 was higher than that at x = 0.25L. • Besides fan Reynolds number, the area ratio also determined Nu of the fin array

  11. Efficiency and optimisation of fin with temperature-dependent thermal conductivity: a simplified solution

    Bouaziz, M.N.; Hanini, S.

    2007-11-15

    An analytical simplified solution is proposed for temperature distribution and fin efficiency, when thermal conductivity is temperature dependent. An optimal linearization technique is used to solve the nonlinear equation. Based on classical solution, some accurate results are obtained and presented with thermal conductivity parameter and fin parameter. Arithmetic mean temperature is less precise than an equivalent thermal conductivity. Optimal thickness for rectangular fin is derived. (orig.)

  12. ENHANCEMENT OF NATURAL CONVECTION HEAT TRANSFER FROM RECTANGULAR FINS BY CIRCULAR PERFORATIONS

    Wadhah Hussein Abdul Razzaq Al- Doori

    2011-12-01

    Full Text Available The importance of heat transfer by natural convection in enclosures can be found in many engineering applications, such as energy transfer in buildings, solar collectors, nuclear reactors and electronic packaging. An experimental study was conducted to investigate heat transfer by natural convection in a rectangular fin plate with circular perforations as heat sinks. The patterns of the perforations included 24 circular perforations (holes for the first fin; the number of perforations increased by eight for each fin to 56 in the fifth fin. These perforations were distributed in 6-14 rows and four columns. Experiments were carried out in an experimental facility that was specifically designed and constructed for this purpose. It was observed that the temperature along the non-perforated fin dropped from 30 to 25°C, but the temperature drop for the perforated fins was from 30 to 23.7°C at low power (6 W. The drop in temperature between the fin base and the tip increased as the diameter of the perforations increased. The temperature drop at the highest power (220 W was from 250 to 49°C for the non-perforated fin and from 250 to 36°C for the perforated fins. The heat transfer rate and the coefficient of heat transfer increased with an increased number of perforations.

  13. Study of flexible fin and compliant joint stiffness on propulsive performance: theory and experiments

    The caudal fin is a major source of thrust generation in fish locomotion. Along with the fin stiffness, the stiffness of the joint connecting the fish body to the tail plays a major role in the generation of thrust. This paper investigates the combined effect of fin and joint flexibility on propulsive performance using theoretical and experimental studies. For this study, fluid–structure interaction of the fin has been modeled using the 2D unsteady panel method coupled with nonlinear Euler–Bernoulli beam theory. The compliant joint has been modeled as a torsional spring at the leading edge of the fin. A comparison of self-propelled speed and efficiency with parameters such as heaving and pitching amplitude, oscillation frequency, flexibility of the fin and the compliant joint is reported. The model also predicts the optimized stiffnesses of the compliant joint and the fin for maximum efficiency. Experiments have been carried out to determine the effect of fin and joint stiffness on propulsive performance. Digital image correlation has been used to measure the deformation of the fins and the measured deformation is coupled with the hydrodynamic model to predict the performance. The predicted theoretical performance behavior closely matches the experimental values. (paper)

  14. A study on heat transfer enhancement using straight and twisted internal fin inserts

    Tijing, Leonard D.; Pak, Bock Choon; Baek, Byung Joon [Chonbuk National Univ., Jeongju (Korea, Republic of); Cho, Young I. [Drexel Univ., Pennsylvania (United States)

    2005-07-01

    The present study investigated the effect of internal aluminum fins with a star shape cross section on the heat transfer enhancement and pressure drop in a counterflow heat exchanger. A concentric tube heat exchanger was used with water as the working fluid. The heat transfer rate increased by 12-51% over the plain tube value, depending on the internal fin configuration used. However, the pressure drop also increased substantially by an average of 286-338%. The results showed that a straight fin configuration is good enough to produce a heat transfer increase in a counterflow heat exchanger. Twisted fin configurations did not further increase the heat transfer rate.

  15. Alternative solutions for longitudinal fins of rectangular, trapezoidal, and concave parabolic profiles

    The traditional thermal analysis of fins is based on the assumption of specified thermal boundary conditions at the base and tip of the fin. For situations when the fin base is in contact with a fluid experiencing condensation and the fin is required to remove the energy released by the fluid, the base is subjected to two boundary conditions: a fixed temperature and a fixed heat flux. This paper develops solutions for the temperature distribution in the fins under these conditions. Solutions are provided for rectangular, trapezoidal, and concave parabolic (finite tip thickness). Results illustrating the relationship between the dimensionless heat flux, the fin parameter, and dimensionless tip temperature are provided for all three geometries. The case of convective fin tip is also considered and lead to a relationship between the dimensionless heat flux, the fin parameter, and the Biot number at the tip. The results presented here provide tools that not only complement the traditional analyses but are believed to have more direct relevance for the fin designers.

  16. Burnout in the boiling of water and freon-113 on tubes with annular fins

    This paper presents the results of numerical calculations of burnout heat flux associated with the boiling of Freon-113 and water on an annular fin of constant thickness which have been approximated by simple analytical relations. These are used to calculate the critical burnout parameters of tubes with an annular fin assembly. The calculated data may be used for the analysis of tubes with an annular fin assembly over a wide range of variation of the thermophysical properties of the material and geometrical parameters of the fin assembly

  17. Incongruence between the sexes in preferences for body and dorsal fin size in Xiphophorus variatus.

    MacLaren, R David; Fontaine, Adam

    2013-01-01

    Female preference for male fin enhancements in poeciliid fishes may be driven by a preexisting perceptual bias for increased male lateral projection area (LPA). This hypothesis suggests that a male with enlarged body and/or fin size projects a larger image onto the female's retina at a given viewing distance, eliciting a greater sensory and thus behavioral response out of the female than a smaller male. Given the shared sensory/neural systems of opposite sex conspecifics, we might expect the LPA bias to also be present in males of at least some poeciliid species. However, we need not expect congruence between the sexes in the state of the bias over evolutionary time. To examine whether the sexes share a bias for sailfin-like dorsal fins, a trait not present in their evolutionary history, the bias favoring increased dorsal fin size and LPA observed in female Xiphophorus variatus, among other poeciliids, was investigated by testing male preference for dummy females varying in dorsal fin size, body size, and dorsal fin:body size ratio. In three sets of simultaneous choice experiments, males preferred females of larger body size when fin size was held constant and when total LPA was held constant, but showed no preference for larger fins when body size was held constant. The LPA bias is therefore less permissive in males than females with selection favoring a male's ability to discriminate between female body size - an indicator of fertility/fecundity - and fin size, which offers no known fitness benefits. PMID:23137586

  18. Female bias for enlarged male body and dorsal fins in Xiphophorus variatus.

    MacLaren, R David; Gagnon, John; He, Ran

    2011-06-01

    Female preference for male fin elaborations in Poeciliid fishes may be driven by a sensory bias for increased lateral projection area (LPA) that has existed since the lineages diverged from a common ancestor. Previous research supports this hypothesis demonstrating female Poecilia latipinna, Poecilia mexicana, and Poecilia reticulata prefer males of larger body and dorsal fin size, but exhibit no such preferences when controlling for total LPA. In the current study, we further tested this hypothesis by presenting female platys, Xiphophorus variatus, with pairs of dummy males differing in: (1) body size (holding dorsal fin size constant); (2) dorsal fin size (holding body size constant); and (3) dorsal fin: body size ratio (holding total LPA constant). Females spent more time near dummies of greater body and dorsal fin size; however, in the third experiment, neither fin size, body size, nor any particular dorsal fin+body size combination was preferred. These results provide additional support for the LPA and sensory bias hypotheses, demonstrating that female X. variatus not only prefer males with "swords", but sailfin-like dorsal fins as well when body size is held constant. Shared preference for increased LPA is consistent with common ancestry of the sensory/neural systems in females of all four species. PMID:21457765

  19. DETERMINATION OF TEMPERATURE DISTRIBUTION FOR ANNULAR FINS WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY BY HPM

    Davood Domairry Ganji

    2011-01-01

    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  20. Effect of an Artificial Caudal Fin on the Performance of a Biomimetic Fish Robot Propelled by Piezoelectric Actuators

    2007-01-01

    This paper addresses the design of a biomimetic fish robot actuated by piezoceramic actuators and the effect of artificial caudal fins on the fish robot's performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fin characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel's fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fin area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.

  1. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    Wang, Zhenlong; Hang, Guanrong; Wang, Yangwei; Li, Jian; Du, Wei

    2008-04-01

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s-1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s-1 and 22° s-1, respectively.

  2. The morphology of the cephalic lobes and anterior pectoral fins in six species of batoids.

    Mulvany, Samantha; Motta, Philip J

    2013-09-01

    Many benthic batoids utilize their pectoral fins for both undulatory locomotion and feeding. Certain derived, pelagic species of batoids possess cephalic lobes, which evolved from the anterior pectoral fins. These species utilize the pectoral fins for oscillatory locomotion while the cephalic lobes are used for feeding. The goal of this article was to compare the morphology of the cephalic lobes and anterior pectoral fins in species that possess and lack cephalic lobes. The skeletal elements (radials) of the cephalic lobes more closely resembled the radials in the pectoral fin of undulatory species. Second moment of area (I), calculated from cephalic lobe radial cross sections, and the number of joints revealed greater flexibility and resistance to bending in multiple directions as compared to pectoral fin radials of oscillatory species. The cephalic lobe musculature was more complex than the anterior pectoral fin musculature, with an additional muscle on the dorsal side, with fiber angles running obliquely to the radials. In Rhinoptera bonasus, a muscle presumably used to help elevate the cephalic lobes is described. Electrosensory pores were found on the cephalic lobes (except Mobula japonica) and anterior pectoral fins of undulatory swimmers, but absent from the anterior pectoral fins of oscillatory swimmers. Pore distributions were fairly uniform except in R. bonasus, which had higher pore numbers at the edges of the cephalic lobes. Overall, the cephalic lobes are unique in their anatomy but are more similar to the anterior pectoral fins of undulatory swimmers, having more flexibility and maneuverability compared to pectoral fins of oscillatory swimmers. The maneuverable cephalic lobes taking on the role of feeding may have allowed the switch to oscillatory locomotion and hence, a more pelagic lifestyle. PMID:23801572

  3. Relying on fin erosion to identify hatchery-reared brown trout in a Tennessee river

    Meerbeek, Jonathan R.; Bettoli, Phillip William

    2012-01-01

    Hatchery-induced fin erosion can be used to identify recently stocked catchable-size brown trout Salmo trutta during annual surveys to qualitatively estimate contributions to a fishery. However, little is known about the longevity of this mark and its effectiveness as a short-term (≤ 1 year) mass-marking technique. We evaluated hatchery-induced pectoral fin erosion as a mass-marking technique for short-term stocking evaluations by stocking microtagged brown trout in a tailwater and repeatedly sampling those fish to observe and measure their pectoral fins. At Dale Hollow National Fish Hatchery, 99.1% (228 of 230) of microtagged brown trout in outdoor concrete raceways had eroded pectoral fins 1 d prior to stocking. Between 34 and 68 microtagged and 26-35 wild brown trout were collected during eight subsequent electrofishing samples. In a blind test based on visual examination of pectoral fins at up to 322 d poststocking, one observer correctly identified 91.7% to 100.0% (mean of 96.9%) of microtagged brown trout prior to checking for microtags. In the laboratory, pectoral fin length and width measurements were recorded to statistically compare the fin measurements of wild and microtagged hatchery brown trout. With only one exception, all pectoral fin measurements on each date averaged significantly larger for wild trout than for microtagged brown trout. Based on the number of pectoral fin measurements falling below 95% prediction intervals, 93.7% (148 of 158) of microtagged trout were correctly identified as hatchery fish based on regression models up to 160 d poststocking. Only 72.2% (70 of 97) of microtagged trout were identified correctly after 160 d based on pectoral fin measurements and the regression models. We concluded that visual examination of pectoral fin erosion was a very effective way to identify stocked brown trout for up to 322 d poststocking.

  4. Embedded SMA wire actuated biomimetic fin: a module for biomimetic underwater propulsion

    An embedded shape memory alloy (SMA) wire actuated biomimetic fin is presented, and based on this module for biomimetic underwater propulsion, a micro robot fish (146 mm in length, 30 g in weight) and a robot squid (242 mm in length, 360 g in weight) were developed. Fish swim by undulating their body and/or fins. Squid and cuttlefish can also swim by undulating their fins. To simplify engineering modeling, the undulating swimming movement is assumed to be the integration of the movements of many flexible bending segments connected in parallel or in series. According to this idea, a biomimetic fin which can bend flexibly was developed. The musculature of a cuttlefish fin was investigated to aid the design of the biomimetic fin. SMA wires act as 'muscle fibers' to drive the biomimetic fin just like the transverse muscles of the cuttlefish fin. During the bending phase, elastic energy is stored in the elastic substrate and skin, and during the return phase, elastic energy is released to power the return movement. Theorem analysis of the bending angle was performed to estimate the bending performance of the biomimetic fin. Experiments were carried out on single-face fins with latex rubber skin and silicone skin (SF-L and SF-S) to compare the bending angle, return time, elastic energy storage and reliability. Silicone was found to be the better skin. A dual-face fin with silicone skin (DF-S) was tested in water to evaluate the actuating performance and to validate the reliability. Thermal analysis of the SMA temperature was performed to aid the control strategy. The micro robot fish and robot squid employ one and ten DF-S, respectively. Swimming experiments with different actuation frequencies were carried out. The speed and steering radius of the micro robot fish reached 112 mm s−1 and 136 mm, respectively, and the speed and rotary speed of the robot squid reached 40 mm s−1 and 22° s−1, respectively

  5. Physical Scaling Limits of FinFET Structure: A Simulation Study

    Gaurav Saini

    2011-03-01

    Full Text Available In this work an attempt has been made to analyze the scaling limits of Double Gate (DG underlap andTriple Gate (TG overlap FinFET structure using 2D and 3D computer simulations respectively. Toanalyze the scaling limits of FinFET structure, simulations are performed using three variables: finthickness,fin-height and gate-length. From 2D simulation of DG FinFET, it is found that the gate-length(L and fin-thickness (Tfin ratio plays a key role while deciding the performance of the device. DrainInduced Barrier Lowering (DIBL and Subthreshold Swing (SS increase abruptly when (L/Tfin ratio goesbelow 1.5. So, there will be a trade-off in between SCEs and on- current of the device since on-off currentratio is found to be high at small dimensions. From 3D simulation study on TG FinFET, It is found thatboth fin-thickness (Tfin and fin-height (Hfin can control the SCEs. However, Tfin is found to be moredominant parameter than Hfin while deciding the SCEs. DIBL and SS increase as (Leff/Tfin ratiodecreases. The (Leff/Tfin ratio can be reduced below 1.5 unlike DG FinFET for the same SCEs. However,as this ratio approaches to 1, the SCEs can go beyond acceptable limits for TG FinFET structure. Therelative ratio of Hfin and Tfin should be maximum at a given Tfin and Leff to get maximum on-current perunit width. However, increasing Hfin degrades the fin stability and degrades SCEs.

  6. Applications of conducting polymers: robotic fins and other devices

    Tangorra, James L.; Anquetil, Patrick A.; Weideman, Nathan S.; Fofonoff, Timothy; Hunter, Ian W.

    2007-04-01

    Conducting polymers are becoming viable engineering materials and are gradually being integrated into a wide range of devices. Parallel efforts conducted to characterize their electromechanical behavior, understand the factors that affect actuation performance, mechanically process films, and address the engineering obstacles that must be overcome to generate the forces and displacements required in real-world applications have made it possible to begin using conducting polymers in devices that cannot be made optimal using traditional actuators and materials. The use of conducting polymers has allowed us to take better advantage of biological architectures for robotic applications and has enabled us to pursue the development of novel sensors, motors, and medical diagnostic technologies. This paper uses the application of conducting polymer actuators to a biorobotic fin for unmanned undersea vehicles (UUVs) as a vehicle for discussing the efforts in our laboratory to develop conducting polymers into a suite of useful actuators and engineering components.

  7. Analysis of CHF experiment data for finned fuel bundle

    The HANARO uses finned-element fuel bundles. For thermal-hydraulic safety analysis, used is the MATRA-h code which is a modified version of KAERI's MATRA-α. The subchannel analysis model was determined by using the in-core irradiation test results and hydraulic experiment results for fuel bundle. The validity of the analysis model was investigated by comparing the MATRA-h predictions with the experimental results from several bundle CHF tests. The comparison showed that the code predictions for the CHF power were very close to or less than the experimental results. Thus, it was confirmed that the subchannel analysis using MATRA-h is to be applicable to the prediction of CHF phenomenon in HANARO fuel bundle

  8. Les besoins des adolescents en fin de vie

    Junod, Félicia; Marini, Gaëlle; Machado Magalhães, Stéfanie; Helou, Nancy

    2016-01-01

    Contexte : Les soins palliatifs ont émergé en réponse au vieillissement démographique. Ils sont donc peu développés au niveau de la pédiatrie, ce qui entrave la continuité des soins pour cette population. Or, l’accès à ces soins pour les adolescents doit être spécifique à leurs besoins. Objectifs : Identifier quels sont les besoins des adolescents en fin de vie. Stratégies de recherche : Deux bases de données ont été utilisées : CINAHL et MedLine, par le biais de mots-clés, de descripteurs et...

  9. Compensation of airflow maldistribution in fin-and-tube evaporators

    Kærn, Martin Ryhl; Tiedemann, Thomas

    2012-01-01

    Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using a...... linear velocity profile and a CFD predicted velocity profile obtained from Kærn (2011d) in dry and wet conditions. The circuitry models are validated experimentally in wet conditions, and for this purpose a test case interlaced evaporator (17.58 kW) was reconstructed in order to become a face split...... evaporator by modifying its U-bend connections. Furthermore, a 14% and 28% blockage of the face split evaporator is studied experimentally with control of individual channel superheats. It is shown that the face split circuitry with compensation gives the best performance in both dry and wet conditions...

  10. Methods and criteria for safety analysis (FIN L2535)

    In response to the NRC request for a proposal dated October 20, 1992, Westinghouse Savannah River Company (WSRC) submit this proposal to provide contractural assistance for FIN L2535, ''Methods and Criteria for Safety Analysis,'' as specified in the Statement of Work attached to the request for proposal. The Statement of Work involves development of safety analysis guidance for NRC licensees, arranging a workshop on this guidance, and revising NRC Regulatory Guide 3.52. This response to the request for proposal offers for consideration the following advantages of WSRC in performing this work: Experience, Qualification of Personnel and Resource Commitment, Technical and Organizational Approach, Mobilization Plan, Key Personnel and Resumes. In addition, attached are the following items required by the NRC: Schedule II, Savannah River Site - Job Cost Estimate, NRC Form 189, Project and Budget Proposal for NRC Work, page 1, NRC Form 189, Project and Budget Proposal for NRC Work, page 2, Project Description