WorldWideScience

Sample records for active vertical 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. 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.

  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. Natural Convection-Radiation from a Vertical Base-Fin Array with Emissivity Determination

    Korada Viswanatha Sharma; Ovinis Mark; Hassan Suhaimi B

    2014-01-01

    Experiments have been conducted to determine the emissivity for black chrome coated and uncoated aluminum surfaces. The emissivity of the surfaces is estimated considering combined convection radiation heat transfer and observed to be a constant in the range of 60 to 110°C. The combined heat transfer coefficients from black chrome coated vertical base vertical fin array of size 70 x 70 mm consisting of 22 aluminum fins with a fin spacing of 10 mm by natural convection and radiation has been d...

  5. Natural Convection-Radiation from a Vertical Base-Fin Array with Emissivity Determination

    Korada Viswanatha Sharma

    2014-07-01

    Full Text Available Experiments have been conducted to determine the emissivity for black chrome coated and uncoated aluminum surfaces. The emissivity of the surfaces is estimated considering combined convection radiation heat transfer and observed to be a constant in the range of 60 to 110°C. The combined heat transfer coefficients from black chrome coated vertical base vertical fin array of size 70 x 70 mm consisting of 22 aluminum fins with a fin spacing of 10 mm by natural convection and radiation has been determined at different heat inputs. Theoretical analysis of single fin geometry of constant thickness considering both convection and radiation has been used to predict the temperature distribution and heat flow. The theoretical values of heat flow estimated for a fin array is in good agreement with the experimental observations validating the emissivity of the surface. The experimental data is further validated with the equations of Nusselt presented by Churchill and Chu.

  6. A numerical study of entry region laminar mixed convection over shrouded vertical fin arrays

    A computational study of laminar mixed convection over a shrouded vertical rectangular fin array attached to a vertical base has been performed. Maintaining the base-fin system above the surrounding temperature, a fan velocity is imposed to enhance the heat transfer through the mixed convection process. Present study finds the effects of clearance spacing, fin spacing, fin length, Reynolds number and Grashof number on the thermal performance of the base-fin system. Mixed convection inlet velocity is decoupled to forced and natural convection velocity components and the resulting pressure drop across the duct length arises purely due to the forced convection velocity component. Thus, Reynolds number is estimated based on forced convection velocity component as the inlet velocity does not vanish even in pure natural convection. Computed local Nusselt number shows sharp drop near the entrance and reaches a fully developed value after a certain stream-wise distance from the entrance. Further, fully developed local Nusselt number shows a clear maximum at the clearance spacing of 0.075 and 0.15 for the inter-fin spacing of 0.3 and 0.5 respectively. Pressure drop across the duct, induced natural convection velocity and overall Nusselt number are well correlated with the governing parameters of the problem. (authors)

  7. Studi Eksperimental Vertical Axis Wind Turbine Tipe Savonius dengan Variasi Jumlah Fin pada Sudu

    Ola Dwi Sandra Hasan

    2013-09-01

    Full Text Available Salah satu  teknologi sistem konversi energi angin  yang ada adalah turbin Savonius yang merupakan salah satu jenis Vertical Axis Wind Turbine ( VAWT . Turbin Savonius  memiliki  karakteristik strating torsi yang baik, mudah dalam pembutannya dan dapat menerima angin dari segala arah namun kekurangan yang dimiliki adalah coefficient of power (Cp turbin yang rendah. Untuk itu banyak dilakukan penelitian untuk meningkatkan efisiensi dari turbin Savonius. Salah satunya adalah penambahan end plate yang mampu meningkatkan perbedaan tekanan dari kedua sisi sudu sehingga memperbesar drag positif turbin. Untuk itu pada penelitian ini dilakukan variasi jumlah penambahan fin pada sudu. Variasi jumlah fin yang dilakukan adalah 1,2,4 dan 7 fin serta pengujian dengan menggunakan generator dan tanpa generator. Dari hasil pengujian, variasi fin yang dapat meningkatkan Cp turbin Savonius adalah variasi 1 fin jika dibandingkan  turbin standarnya dengan nilai Cp sebesar 0,11.  SKEA turbin Savonius menggunakan generator 12 V;400W dapat  menghasilkan daya maksimal 5,71 Watt pada putaran 134 rpm

  8. Computational heat transfer analysis and combined ANN–GA optimization of hollow cylindrical pin fin on a vertical base plate

    C Balachandar; S Arunkumar; M Venkatesan

    2015-09-01

    In the devices like laptops, microprocessors, the electric circuits generate heat while performing work which necessitates the use of fins. In the present work, the heat transfer characteristics of hollow cylindrical pin fin array on a vertical rectangular base plate is studied using commercial CFD code ANSYS FLUENT© . The hollow cylindrical pin fins are arranged inline. The heat transfer augmentation is studied for different parameters such as inner radius, outer radius, height of the fins and number of pin fins. The base plate is supplied with a constant heat flux in the range of 20–500W. The base plate dimensions are kept constant. The base plate temperature is predicted using Artificial Neural Network (ANN) by training the network based on the results of numerical simulation. The trained ANN is used to analyse the fin in terms of enhanced heat transfer and weight reduction when compared to solid pin fin. Optimization of the hollow cylindrical pin fin parameters to obtain maximum heat transfer from the base plate is carried out using Genetic Algorithm (GA) applied on the trained neural network. The analysis using the numerical simulation and neural network shows that the hollow fins provide an increased heat transfer and a weight reduction of about 90% when compared to solid cylindrical pin fins.

  9. 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

  10. Experimental investigation of the effect vertical oscillation on the heat transfer coefficient of the finned tube

    Kadhim S. K.

    2016-01-01

    Full Text Available The aim of this work is to investigate experimentally the effect of the forced vibrations on the free convection heat transfer coefficient using heated longitudinally finned cylinder made of Aluminium. The effect of the vibration frequency ranged from 2 to16 Hz with various heat fluxes ranged from 500-1500 W/m2. It was found that, the relation between the heat transfer coefficient and amplitude of vibration increased for all inclination angles from (0°-45°, while the increment of inclination angle decreases the values of convection heat transfer coefficient. The results show that the heat transfer coefficient ratio (hv/ho of longitudinal finned cylinders in (0° angle was (8% and (30% greater than those for the (30° and (45° respectively.

  11. Two-phase flow regime observations in a vertical hexagonal flow channel with and without a finned fuel bundle

    Previous flow regime studies have been for horizontal, vertical, and inclined pipe flow. As such, only a few studies have been performed on bundle geometries. The present paper examines the flow regimes for a vertical hexagonal flow channel with and without a finned fuel bundle. This type of a 36 finned rod hexagonal fuel bundle in parallel hexagonal flow channels is used in a MAPLE (Multi- purpose Applied Physics Lattice Experimental) type nuclear reactor. An experiment apparatus was designed consisting of the flow channel, inlet plenum and an air-water separator. The inlet plenum is used to provide a uniform mixture of air and water before entering the hexagonal flow channel. A turbine flow meter is used to determine the water flow rate. The turbine flow meter is calibrated for a low flow range and limits the measurable flow to 50 l/min. Flow pattern observation is determined by a SONY video camera, Real-Time Neutron Radiography, pressure transducer and capacitance transducer. The Sony video camera provides visual observation through a Lucite flow channel. The Real-Time Neutron Radiography system allows for flow visualization through an Aluminum flow channel. The pressure drop is correlated by the Validyne pressure transducer and the capacitance transducer provides the void fraction relationship

  12. Characterization of working fluid in vertically mounted finned U-shape twin heat pipe for electronic cooling

    Highlights: ► Detailed characterization of working fluid of vertical finned U-shape heat pipe. ► The present configuration, considering the working fluid, was not studied previously. ► The low difference in evaporator and condenser temperatures enhances heat transfer. ► The high pressure drop across the porous wick causes easy return flow of the liquid. ► The predicted evaporator and condenser temperatures are validated by experiment. - Abstract: As part of the ongoing research on finned U-shape heat pipes for CPU cooling, the present work focuses on the characterization of working fluid in vertically oriented twin U-shape heat pipe, by taking into account the gravity of flow. Two-dimensional FE simulation is performed under natural and forced convection modes, by using ANSYS-FLOTRAN. The best heat input and coolant velocity for the simulations are determined experimentally, corresponding to the least thermal resistance. The wall temperatures at the evaporator, adiabatic and condenser sections, and the velocity and pressure distributions of vapor and liquid, are analyzed. The total heat input for minimum thermal resistance in both natural and forced convection is found to be 50 W, and the coolant velocity is 3 m/s. The predicted and experimental wall temperatures are found in excellent match. It is observed that for the present U-shape heat pipe configuration, the difference in evaporator and condenser temperatures is significantly small, resulting in enhanced heat transfer compared to the conventional heat pipes. The sintered copper wick has a small pore size, resulting in low wick permeability, leading to the generation of high capillary forces for anti-gravity applications.

  13. Studi Eksperimental Vertical Axis Wind Turbine Tipe Savonius dengan Variasi Jumlah Fin pada Sudu

    Ola Dwi Sandra Hasan; Ridho Hantoro; Gunawan Nugroho

    2013-01-01

    Salah satu  teknologi sistem konversi energi angin  yang ada adalah turbin Savonius yang merupakan salah satu jenis Vertical Axis Wind Turbine ( VAWT ). Turbin Savonius  memiliki  karakteristik strating torsi yang baik, mudah dalam pembutannya dan dapat menerima angin dari segala arah namun kekurangan yang dimiliki adalah coefficient of power (Cp) turbin yang rendah. Untuk itu banyak dilakukan penelitian untuk meningkatkan efisiensi dari turbin Savonius. Salah satunya adalah penambahan end pl...

  14. 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.

  15. 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

  16. How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

    Wensveen, Paul J; von Benda-Beckmann, Alexander M; Ainslie, Michael A; Lam, Frans-Peter A; Kvadsheim, Petter H; Tyack, Peter L; Miller, Patrick J O

    2015-05-01

    The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement). PMID:25795075

  17. 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.

  18. 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.

  19. Analysis of the heat transfer mechanisms during energy storage in a Phase Change Material filled vertical finned cylindrical unit for free cooling application

    Highlights: • Freezing behavior of a PCM, in a cylinder with annular longitudinal fins is presented. • Among various fin heights, 20 mm fin contribute maximum heat transfer enhancement. • Addition of fins plays a contradictory role during the sensible cooling of liquid PCM. • The fin effect along with external cooling, vary the sensible cooling rate of liquid PCM. • The surface convective resistance dominated over the conductive resistance of PCM. - Abstract: The heat transfer performance of the Phase Change Material (PCM) used in free cooling application is low due to poor thermal conductivity. The addition of fins to enhance the heat transfer during solidification process is commonly employed, to address this. However for application such as free cooling, where the driving temperature potential is very less, the present experimental study is intended to investigate the sensible and subcooling phenomena during the outward cylindrical solidification of the PCM stored on the annulus side, along with 8 longitudinal uniformly spaced copper fins of different heights. The performance of the fins during solidification is analyzed, and the best suitable height is arrived at. The addition of fins plays a contradicting role during the sensible cooling of the liquid PCM, due to the suppression of free convection. The external cooling conditions along with the effect of the fin, vary the sensible cooling rate of the liquid PCM, that influences the subcooling effect, and also drifts the temperature at which major phase change occurs. In addition, the effects due to the inlet velocity of the heat transfer fluid, and its temperature on heat transfer are investigated and reported. The increase in velocity decreases the duration of solidification, and this effect is more pronounced towards the entry region, due to the higher local convective heat transfer co-efficient and a comparatively higher driving temperature potential

  20. Activity Based Startup Plan for Prototype Vertical Denitration Calciner

    Testing activities on the Prototype Vertical Denitration Calciner at PFP were suspended in January 1997 due to the hold on fissile material handling in the facility. The restart of testing activities will require a review through an activity based startup process based upon Integrated Safety Management (ISM) principles to verify readiness. The Activity Based Startup Plan has been developed for this process

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.)

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. 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

  13. Active vibration control based on piezoelectric smart composite

    An aircraft’s vertical fin may experience dramatic buffet loads in high angle of attack flight conditions, and these buffet loads would cause huge vibration and dynamic stress on the vertical fin structure. To reduce the dynamic vibration of the vertical fin structure, macro fiber composite (MFC) actuators were used in this paper. The drive moment equations and sensing voltage equations of the MFC actuators were developed. Finite element analysis models based on three kinds of models of simplified vertical fin structures with surface-bonded MFC actuators were established in ABAQUS. The equivalent damping ratio of the structure was employed in finite element analysis, in order to measure the effectiveness of vibration control. Further, an open-loop test for the active vibration control system of the vertical fin with MFC actuators was designed and developed. The experimental results validated the effectiveness of the MFC actuators as well as the developed methodology. (paper)

  14. 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

  15. 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

  16. 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.

  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. Vertical Farming

    Molina Núñez, Antonio José

    2012-01-01

    El fin de la instalación es producir frutas y verduras utilizando la menor superficie posible en planta, debido a la escasez y encarecimiento de esta, incremento de la población y desertificación. Para ello esta modalidad de plantación, Vertical farming, utiliza el desarrollo en altura, aprovechando la superficie lo máximo posible combinado con una nueva técnica, hidroponia, que es la forma de cultivar las plantas sin tierra. Facultad de Ciencias de la Empresa Universidad...

  19. 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.

  20. The mutual relations between solar activity, thunderstorms and Vertical Gradients of Electro Atmospheric Potential

    C. SCUTERINI

    1974-06-01

    Full Text Available The mutual relations are established between solar activity expressed in Wolf numbers, the vertical gradient of electro atmospheric potential measured in the Geophysical Observatory of Macerata, the geomagnetic field measured in the Observatory of the nearby town of Aquila, and the thunderstorm activity over the whole of the Italian territory. The mutual relationship between the vertical gradient, the geomagnetic field and the frequency of thunderstorms and solar activity are clearly evident. In particular the antiparallel behavior between solar activity and the vertical gradient, as well as thunderstorm frequency lias been made clear by observations carried out over a period of 22 years. The results obtained from a study of the geomagnetic field and the vertical gradients agree with the research on a much shorter period of time recently carried out by Rao. Observational values have been treated as statistical elements (2 to enable smoother readings, without however moving the maximums and mínimums of the phenomenon in the given period of time so that parallelisms and antiparallelisms resulting from theso observational values are kept. The average values of the vertical gradients of electro atmospheric potential were derived for electrically calm days. From these 5 days per month were chosen by probability method; the averages were then calculated on these five days chosen stochastically. We considered an electrically calm day one in which the sky was absolutely clear, with no thunderstorms either in the vicinity or far from the observatory, with neither fog or haze present.

  1. Active low-frequency vertical vibration isolation system for precision measurements

    Wu, Kang; Li, Gang; Hu, Hua; Wang, Lijun

    2016-06-01

    Low-frequency vertical vibration isolation systems play important roles in precision measurements to reduce seismic and environmental vibration noise. Several types of active vibration isolation systems have been developed. However, few researches focus on how to optimize the test mass install position in order to improve the vibration transmissibility. An active low-frequency vertical vibration isolation system based on an earlier instrument, the Super Spring, is designed and implemented. The system, which is simple and compact, consists of two stages: a parallelogram-shaped linkage to ensure vertical motion, and a simple spring-mass system. The theoretical analysis of the vibration isolation system is presented, including terms erroneously ignored before. By carefully choosing the mechanical parameters according to the above analysis and using feedback control, the resonance frequency of the system is reduced from 2.3 to 0.03 Hz, a reduction by a factor of more than 75. The vibration isolation system is installed as an inertial reference in an absolute gravimeter, where it improved the scatter of the absolute gravity values by a factor of 5. The experimental results verifies the improved performance of the isolation system, making it particularly suitable for precision experiments. The improved vertical vibration isolation system can be used as a prototype for designing high-performance active vertical isolation systems. An improved theoretical model of this active vibration isolation system with beam-pivot configuration is proposed, providing fundamental guidelines for vibration isolator design and assembling.

  2. Direction-dependent activation of the insular cortex during vertical and horizontal hand movements.

    Rousseau, C; Fautrelle, L; Papaxanthis, C; Fadiga, L; Pozzo, T; White, O

    2016-06-14

    The planning of any motor action requires a complex multisensory processing by the brain. Gravity - immutable on Earth - has been shown to be a key input to these mechanisms. Seminal fMRI studies performed during visual perception of falling objects and self-motion demonstrated that humans represent the action of gravity in parts of the cortical vestibular system; in particular, the insular cortex and the cerebellum. However, little is known as to whether a specific neural network is engaged when processing non-visual signals relevant to gravity. We asked participants to perform vertical and horizontal hand movements without visual control, while lying in a 3T-MRI scanner. We highlighted brain regions activated in the processing of vertical movements, for which the effects of gravity changed during execution. Precisely, the left insula was activated in vertical movements and not in horizontal movements. Moreover, the network identified by contrasting vertical and horizontal movements overlapped with neural correlates previously associated to the processing of simulated self-motion and visual perception of the vertical direction. Interestingly, we found that the insular cortex activity is direction-dependent which suggests that this brain region processes the effects of gravity on the moving limbs through non-visual signals. PMID:27001175

  3. 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

  4. 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

  5. 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

  6. Microbial activities in a vertical-flow wetland system treating sewage sludge with high organic loads

    The rhizosphere is the most active zone in treatment wetlands where take place physicochemical and biological processes between the substrate, plants, microorganisms, and contaminants. Microorganisms play the key role in the mineralisation of organic matter. substrate respiration and phosphatase activities (acid and alkaline) were chosen as indicators of microbial activities, and studied in a vertical-flow wetland system receiving sewage sludge with high organic loads under the Mediterranean climate. (Author)

  7. 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...

  8. Trunk Muscle Activation and Estimating Spinal Compressive Force in Rope and Harness Vertical Dance.

    Wilson, Margaret; Dai, Boyi; Zhu, Qin; Humphrey, Neil

    2015-12-01

    Rope and harness vertical dance takes place off the floor with the dancer suspended from his or her center of mass in a harness attached to a rope from a point overhead. Vertical dance represents a novel environment for training and performing in which expected stresses on the dancer's body are different from those that take place during dance on the floor. Two male and eleven female dancers with training in vertical dance performed six typical vertical dance movements with electromyography (EMG) electrodes placed bilaterally on rectus abdominus, external oblique, erector spinae, and latissimus dorsi. EMG data were expressed as a percentage of maximum voluntary isometric contraction (MVIC). A simplified musculoskeletal model based on muscle activation for these four muscle groups was used to estimate the compressive force on the spine. The greatest muscle activation for erector spinae and latissimus dorsi and the greatest trunk compressive forces were seen in vertical axis positions where the dancer was moving the trunk into a hyper-extended position. The greatest muscle activation for rectus abdominus and external oblique and the second highest compressive force were seen in a supine position with the arms and legs extended away from the center of mass (COM). The least muscle activation occurred in positions where the limbs were hanging below the torso. These movements also showed relatively low muscle activation compression forces. Post-test survey results revealed that dancers felt comfortable in these positions; however, observation of some positions indicated insufficient muscular control. Computing the relative contribution of muscles, expressed as muscle activation and estimated spinal compression, provided a measure of how much the muscle groups were working to support the spine and the rest of the dancer's body in the different movements tested. Additionally, identifying typical muscle recruitment patterns in each movement will help identify key exercises

  9. Performance Enhancement of a Full-Scale Vertical Tail Model Equipped with Active Flow Control

    Whalen, Edward A.; Lacy, Douglas; Lin, John C.; Andino, Marlyn Y.; Washburn, Anthony E.; Graff, Emilio; Wygnanski, Israel J.

    2015-01-01

    This paper describes wind tunnel test results from a joint NASA/Boeing research effort to advance active flow control (AFC) technology to enhance aerodynamic efficiency. A full-scale Boeing 757 vertical tail model equipped with sweeping jet actuators was tested at the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The model was tested at a nominal airspeed of 100 knots and across rudder deflections and sideslip angles that covered the vertical tail flight envelope. A successful demonstration of AFC-enhanced vertical tail technology was achieved. A 31- actuator configuration significantly increased side force (by greater than 20%) at a maximum rudder deflection of 30deg. The successful demonstration of this application has cleared the way for a flight demonstration on the Boeing 757 ecoDemonstrator in 2015.

  10. 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 & ...

  11. Effect of the Kinesio tape to muscle activity and vertical jump performance in healthy inactive people

    Lu Szu-Ching

    2011-08-01

    Full Text Available Abstract Background Elastic taping applied on the triceps surae has been commonly used to improve the performance of lower extremities. However, little objective evidence has been documented. The purpose of this study was to investigate the effect of elastic taping on the triceps surae during a maximal vertical jump. It was hypothesized that elastic taping to the triceps surae would increase muscle activity and cause positive effect to jump height. Methods Thirty-one healthy adults (19 males and 12 females with mean age, body weight and height for 25.3 ± 3.8 years old, 64.1 ± 6.2 kg, and 169.4 ± 7.3 cm, respectively were recruited. All participants performed vertical jump tests prior to (without taping and during elastic taping. Two elastic tapes, Kinesio tape and Mplacebo tape from two different manufacturers, were applied to the participants, respectively. Results The results showed that the vertical ground reaction force increased when Kinesio tape was applied even when the height of jump remained about constant. However, the height of the jump decreased, and there was no difference on the vertical ground reaction force in Mplacebo taping group. Although the EMG activity of medial gastrocnemius tended to increase in Kinesio taping group, we did not see differences in EMG activity for the medial gastrocnemius, tibialis anterior and soleus muscles in either group. Conclusions Based on the varied effects of Kinesio tape and Mplacebo tape, different intervention technique was suggested for specific purpose during vertical jump movement. Mplacebo tape was demanded for the benefits of stabilization, protection, and the restriction of motion at the ankle joint. On the other hand, the findings may implicate benefits for medial gastrocnemius muscle strength and push-off force when using Kinesio tape.

  12. Stability and control characteristics of a monoplanar missile configuration with triform-tail-fin arrangements at Mach numbers from 1.70 to 2.86

    Lamb, M.

    1981-01-01

    A wind-tunnel missile model with either a lower vertical tail fin with a pair of horizontal fins having 0 deg, 22.5 deg, or 30 deg dihedral or an upper vertical tail fin with horizontal fins having 0 deg, -22.5 deg, or -30 deg dihedral was investigated. The results indicated that those configurations with horizontal fins at or below the horizontal plane had nearly linear pitching-moment characteristics, while those with the horizontal fins above the horizontal plane experienced pitch-up which increased with increasing horizontal-fin-dihedral angle. At zero angle of attack, the configurations were directionally stable at most test Mach numbers. Generally, those configurations with the upper vertical fin had positive effective dihedral at zero angle of attack, while those with he lower vertical fin had negative effective dihedral. For roll control, three deflected tail fins produced more total roll control than two horizontal fins. For yaw control, three tail fins deflected equally or differentially produced more total yaw control than the single vertical fin.

  13. 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

  14. Vertical slip rates of active faults of southern Albania inferred from river terraces

    Oswaldo Guzmán; Jean-Louis Mugnier; Riccardo Vassallo; Rexhep Koçi; François Jouanne

    2014-01-01

    Fluvial terraces of Shkumbin, Devoll, Osum and Vjosa rivers (southern Albania and northwestern Greece) are studied in order to quantify the vertical slip rates of the large active faults of the Dinaric-Albanic-Hellenic Alpine fold belt. The spatial and temporal variations of the incision rates along these rivers were estimated from the geomorphological mapping of the Quaternary sediments, the geometry and the dating of the terraces. Eleven terraces levels were identified in Albania from 68 ge...

  15. Effect of the Kinesio tape to muscle activity and vertical jump performance in healthy inactive people

    Lu Szu-Ching; Hsieh Tsung-Hsun; Huang Chen-Yu; Su Fong-Chin

    2011-01-01

    Abstract Background Elastic taping applied on the triceps surae has been commonly used to improve the performance of lower extremities. However, little objective evidence has been documented. The purpose of this study was to investigate the effect of elastic taping on the triceps surae during a maximal vertical jump. It was hypothesized that elastic taping to the triceps surae would increase muscle activity and cause positive effect to jump height. Methods Thirty-one healthy adults (19 males ...

  16. Effect of the neuromuscular activation of knee extensors on vertical jump by using electrostimulation method

    Bílý, Jiří; Cacek, Jan

    2014-01-01

    Neuromuscular electrical stimulation is one of the methods of strength development during which there is no voluntary muscle contraction. The aim of this study was to investigate the influence of the neuromuscular activation of knee extensors on vertical jump by using electrostimulation method. Ten healthy trained male students in sports-sciences, aged 21-25 years, perform Sargent jump test. They perform two kinds of jump - squat jump and drop jump (42 cm heigh bench) immediately after electr...

  17. Vertical Position Control for Top Tensioned Riser with Active Heave Compensator

    Leira, Bernt J.; Fang, Shaoji; Blanke, Mogens

    2011-01-01

    The top and bottom angles of a marine riser are of crucial importance during e.g. drilling and workover operations. A ver- tical position control with active heave compensator (AHC) is proposed to maintain the safety of the riser when subjected to environmental excitations. The possibility of...... reducing the maxi- mum angular response level by adjusting the vertical rod position by means of an active heave compensator is investigated with a positioning algorithm based on adaptive backstepping. Riser top and bottom angles are dealt with by the algorithm in order to minimize both angles....

  18. 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...

  19. Soil microbial abundances and enzyme activities in different rhizospheres in an integrated vertical flow constructed wetland

    Ge, Ying; Jiang, Yueping; Jiang, Qinsu; Min, Hang; Fan, Haitian; Zeng, Qiang; Chang, Jie [College of Life Sciences, Zhejiang University, Hangzhou (China); Zhang, Chongbang [School of Life Sciences, Taizhou University, Linhai (China); Yue, Chunlei [Zhejiang Forestry Academy, Hangzhou (China)

    2011-03-15

    Rhizosphere microorganism is an important bio-component for wastewater treatment in constructed wetlands (CWs). Microbial abundance and enzyme activities in the rhizospheres of nine plant species were investigated in an integrated vertical-flow CW. The abundance of denitrifiers, as well as urease, acid, and alkaline phosphatase activities were positively correlated to plant root biomass. The abundance of bacteria, fungi, actinomycetes, ammonifiers, denitrifiers, and phosphorus decomposers, related to nutrient removal efficiencies in CWs, greatly varied among rhizospheres of different plant species (p < 0.05). Significant differences in rhizosphere enzyme activity among plant species were also observed (p < 0.05), with the exception of catalase activity. The principal component analysis using the data of microbial abundance and enzyme activity showed that Miscanthus floridulus, Acorus calamus, and Reineckia carnea were candidates to be used in CWs to effectively remove nitrogen and phosphorus from wastewater. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. 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

  1. Vertical slip rates of active faults of southern Albania inferred from river terraces

    Oswaldo Guzmán

    2014-02-01

    Full Text Available Fluvial terraces of Shkumbin, Devoll, Osum and Vjosa rivers (southern Albania and northwestern Greece are studied in order to quantify the vertical slip rates of the large active faults of the Dinaric-Albanic-Hellenic Alpine fold belt. The spatial and temporal variations of the incision rates along these rivers were estimated from the geomorphological mapping of the Quaternary sediments, the geometry and the dating of the terraces. Eleven terraces levels were identified in Albania from 68 geochronological ages already published or acquired for this work. The five lower terraces of the four studied rivers are well dated (10 new and 23 already published ages. These terraces are younger than 30 ka and their remnants are numerous. Their restoration allows estimating the regional trend of incision rate and the identification of local shifts. We argue that these shifts are linked to the active tectonics when they coincide with the faults already mapped by previous authors. Vertical slip rates for eight active faults in southern Albania are thus estimated for the last 19 ka and vary from ~0.1 to ~2 mm/a. The Lushnje Tepelene Thrust, that extends more than 120 kilometers, has a throw rate that varies from 0.2 to 0.8 mm/a, whereas the active faults of the extensional domain are segmented but are very active, with throw rates reaching locally 2 mm/a.

  2. 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...

  3. Biomechanical examination of the ‘plateau phenomenon’ in ActiGraph vertical activity counts

    This paper determines if the leveling off (‘plateau/inverted-U’ phenomenon) of vertical ActiGraph activity counts during running at higher speeds is attributable to the monitor's signal filtering and acceleration detection characteristics. Ten endurance-trained male participants (mean (SD) age = 28.2 (4.7) years) walked at 3, 5 and 7 km h−1, and ran at 8, 10, 12, 14, 16, 18 and 20 km h−1 on a force treadmill while wearing an ActiGraph GT3X monitor at the waist. Triaxial accelerations of the body's center of mass (CoM) and frequency content of these accelerations were computed from the force treadmill data. GT3X vertical activity counts demonstrated the expected ‘plateau/inverted-U’ phenomenon. In contrast, vertical CoM accelerations increased with increasing speed (1.32 ± 0.26 g at 10 km h−1 and 1.68 ± 0.24 g at 20 km h−1). The dominant frequency in the CoM acceleration signals increased with running speed (14.8 ± 3.2 Hz at 10 km h−1 and 24.8 ± 3.2 Hz at 20 km h−1) and lay beyond the ActiGraph band-pass filter (0.25 to 2.5 Hz) limits. In conclusion, CoM acceleration magnitudes during walking and running lie within the ActiGraph monitor's dynamic acceleration detecting capability. Acceleration signals of higher frequencies that are eliminated by the ActiGraph band-pass filter may be necessary to distinguish among exercise intensity at higher running speeds. (paper)

  4. Three dimensional MHD Modeling of Vertical Kink Oscillations in an Active Region Plasma Curtain

    Ofman, Leon; Srivastava, Abhishek K

    2015-01-01

    Observations on 2011 August 9 of an X6.9-class flare in active region (AR) 11263 by the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO), were followed by a rare detection of vertical kink oscillations in a large-scale coronal active region plasma curtain in EUV coronal lines. The damped oscillations with periods in the range 8.8-14.9 min were detected and analyzed recently. Our aim is to study the generation and propagation of the MHD oscillations in the plasma curtain taking into account realistic 3D magnetic and density structure of the curtain. We also aim at testing and improving coronal seismology for more accurate determination of the magnetic field than with standard method. We use the observed morphological and dynamical conditions, as well as plasma properties of the coronal curtain based on Differential Emission Measure (DEM) analysis to initialize a 3D MHD model of its vertical and transverse oscillations by implementing the impulsively excited velocity pulse mimick...

  5. Examining the Magnetic Field Strength and the Horizontal and Vertical Motions in an Emerging Active Region

    Lin, Chia-Hsien

    2016-01-01

    Earlier observational studies have used the time evolution of emerging magnetic flux regions at the photosphere to infer their subsurface structures, assuming that the flux structure does not change significantly over the near-surface layer.In this study, we test the validity of this assumption by comparing the horizontal and vertical motions of an emerging active region. The two motions would be correlated if the emerging structure is rigid. The selected active region (AR) NOAA 11645 is not embedded in detectable preexisting magnetic field. The observed horizontal motion is quantified by the separation of the two AR polarities and the extension of the region. The vertical motion is derived from the magnetic buoyancy theory. Our results show that the separation of the polarities is fastest at the beginning with a velocity of $\\approx$~4~Mm hr$^{-1}$ and decreases to $\\le$~1~Mm hr$^{-1}$ after the main growing phase of flux emergence. The derived thick flux-tube buoyant velocity is between 1 and 3~Mm hr$^{-1}$...

  6. Enhanced photoelectrochemical activity of vertically aligned ZnO-coated TiO2 nanotubes

    Vertically aligned ZnO-TiO2 hetero-nanostructures constructed of anatase TiO2 nanotubes (NTs) and wurtzite ZnO coatings are fabricated by atomic layer deposition of ZnO coatings on electrochemical anodization formed TiO2 NTs, and their photoelectrochemical activities are studied through photoelectrochemical and electrochemical characterization. Compared with bare TiO2 NTs, the transient photocurrent increases to over 1.5-fold for the annealed ZnO-coated TiO2 NTs under visible illumination. The ZnO-coated TiO2 NTs also show a longer electron lifetime, a lower charge-transfer resistance and a more negative flat-band potential than the bare TiO2 NTs, confirming the improved photoelectrochemical activity due to the enhanced charge separation

  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. FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System

    Yan-yang Wang

    2014-01-01

    Full Text Available The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV. The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.

  9. Differential susceptibility of horizontal and vertical swimming activity to cadmium exposure in a gammaridean amphipod (Gammarus lawrencianus)

    In this study two indices of swimming behavior (horizontal and vertical swimming activity) in a gammaridean amphipod (Gammarus lawrencianus) were examined for their sensitivity to Cd exposure. G. lawrencianus were exposed for 72 h to a variety of Cd concentrations [background (∼12), 62, 125, 250 and 500 μg l-1] at 20 ppt. Subsequent to exposure, video surveillance of survivors held within grooved rings or clear boxes was used to assess horizontal swimming activity (percentage of time mobile) and vertical swimming activity (number of surfacings), respectively. Results show that control amphipods were quite active, being mobile ∼61% of the time, with horizontal swimming activity decreasing (P -1. Vertical swimming activity in amphipods was also impacted by Cd exposure (P -1) and 62 μg l-1 (60 versus ∼26 surfacings, respectively), which is approximately four-fold lower than the estimated 72 h LC50 (250 μg l-1) for G. lawrencianus. Based on fluid dynamic considerations, it is speculated that of the two behaviors, vertical swimming activity is more sensitive to Cd exposure because of the presumed greater energetic costs associated with producing enough thrust to attain the lift required to make a vertical ascent into the water

  10. Natural convection heat transfer from fin arrays-experimental and theoretical study on effect of inclination of base on heat transfer

    S.V. Naidu; V. Dharma Rao; B. Govinda Rao; A. Sombabu; B. Sreenivasulu

    2010-01-01

    The problem of natural convection heat transfer from fin arrays with inclination is studied experimentally and theoretically to find the effect of inclination of the base of the fin array on heat transfer rate. A numerical model is developed by taking an enclosure, which is formed by two adjacent vertical fins and horizontal base. Results obtained from this enclosure are used to predict heat transfer rate from the fin array. All the governing equations related to fluid in the enclosure, toget...

  11. 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

  12. 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.

  13. 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)...

  14. 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...

  15. 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...

  16. Active bacterial community structure along vertical redox gradients in Baltic Sea sediment

    Jansson, Janet; Edlund, Anna; Hardeman, Fredrik; Jansson, Janet K.; Sjoling, Sara

    2008-05-15

    Community structures of active bacterial populations were investigated along a vertical redox profile in coastal Baltic Sea sediments by terminal-restriction fragment length polymorphism (T-RFLP) and clone library analysis. According to correspondence analysis of T-RFLP results and sequencing of cloned 16S rRNA genes, the microbial community structures at three redox depths (179 mV, -64 mV and -337 mV) differed significantly. The bacterial communities in the community DNA differed from those in bromodeoxyuridine (BrdU)-labeled DNA, indicating that the growing members of the community that incorporated BrdU were not necessarily the most dominant members. The structures of the actively growing bacterial communities were most strongly correlated to organic carbon followed by total nitrogen and redox potentials. Bacterial identification by sequencing of 16S rRNA genes from clones of BrdU-labeled DNA and DNA from reverse transcription PCR (rt-PCR) showed that bacterial taxa involved in nitrogen and sulfur cycling were metabolically active along the redox profiles. Several sequences had low similarities to previously detected sequences indicating that novel lineages of bacteria are present in Baltic Sea sediments. Also, a high number of different 16S rRNA gene sequences representing different phyla were detected at all sampling depths.

  17. Vertical distribution of 137Cs activity concentration in marine sediments at Amvrakikos Gulf, western of Greece

    The aim of the present work is the study of 137Cs migration in sediment column taking into account the sedimentation rate in the Amvrakikos Gulf, at the western part of Greece. Marine core sediments were collected and the measurements were performed using the high resolution gamma-ray spectrometry method. The vertical distribution of 137Cs activity concentration, as part of anthropogenic marine radioactivity, provided averaged sedimentation rate by identifying the depths of activity concentrations due to the Chernobyl accident and the nuclear tests signals. Furthermore, 137Cs measurements were reproduced using the proposed one-dimensional diffusion–advection model which provides mainly as an output, the sedimentation rate and the average diffusivity of 137Cs in the sediment column. The proposed model estimates the temporal variation of 137Cs activity concentration from 1987 (one year after the Chernobyl accident) till today (2014). - Highlights: • Two sediment cores were studied using 137Cs as a tracer. • Two peaks are observed due to nuclear tests and Chernobyl accident. • Diffusivities, as well as 137Cs apparent sedimentation speeds are estimated

  18. Effect of occlusal vertical dimension on swallowing patterns and perioral electromyographic activity.

    MacAvoy, S K; Jack, H C; Kieser, J; Farella, M

    2016-07-01

    Abnormal swallow patterns have been associated with specific dentofacial traits, such as an anterior open bite, but the cause-effect relationship between swallowing and malocclusion remains highly controversial. The aim of this research was to determine the effects of acute change in occlusal vertical dimension (OVD) on intraoral pressure swallow patterns and perioral electromyographic activity (EMG) during swallowing. Ten volunteers (five female, five male; 27-32 years) repeated standardised swallowing tasks as the OVD was progressively increased using mandibular trays of different heights. Standardised swallowing tasks were performed repetitively with each tray in place. Individual swallowing waveforms were quantitatively and qualitatively analysed. Peak pressure, swallow duration, time to peak pressure and lip EMG peak activity were assessed for each swallow. Data were analysed using mixed-model analysis. As OVD increased, lip peak pressure during swallowing increased almost threefold (+2·1 kPa; P ≤ 0·001), whereas swallow duration increased by 12·7 per cent (+160 ms; P = 0·01) at lip level and by 26·4 per cent (+270 ms; P < 0·001) at tongue level. Perioral muscle activity during swallows increased by 43·7 per cent (P ≤ 0·01) up to the OVD where resting lip seal was not attainable. Swallowing waveforms varied markedly between individuals, but interindividual waveforms were only minimally affected. The adaptive response and the waveform similarities associated with OVD variation supports the existence of a central control mechanism for swallowing, which may be modified by peripheral inputs. PMID:27027864

  19. 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...

  20. Bilinear Robust Control for Vertical Vibration in Railway Vehicle with Semi-Active Suspensions

    Umehara, Ryuichi; Otsuki, Masatsugu; Yoshida, Kazuo

    It is well known that the vibration control problem for automobiles and railway vehicles with semi-active suspensions is classified as a control problem in a bilinear system. Bullet trains and railway vehicles have lighter body in order to improve acceleration; these vibrations in the body are easily induced by various disturbances due to rigid and elastic dynamics. Currently, passive dampers such as air suspensions and axle springs are installed on railway vehicle trucks as countermeasures for such vibrations. This study presents an effective controller, based on the H∞ theory, for vibration suppression in railway vehicles and describes a method of synthesizing this robust controller by considering unstructured and structured uncertainties that are applicable to a bilinear system. The performance of the proposed controller and its robustness toward uncertainties are examined by numerical calculations that simulate a railway vehicle subjected to disturbances due to vertical uneven railway tracks, the variations in its mass due to boarding passengers, and the modeling errors caused by non-controlled modes. This enables a comparison of the proposed control method with the conventional one in terms of the robustness toward parameter variation. Thus, this result shows the high robustness and usefulness of the proposed controller.

  1. 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.

  2. Port activities, hinterland congestion, and optimal government policies: The role of vertical integration in logistic operations

    DE BORGER; Bruno; DE BRUYNE, Denis

    2010-01-01

    We study the implications of vertical integration in logistics and transport operations for welfare-optimal port access charges and hinterland congestion tolls. We show that, first, vertical integration of terminal operators and transport firms does not affect the optimal congestion toll rule for the hinterland, but it does imply higher optimal port access charges. Second, the government not only has an incentive to promote competition between downstream firms, it may also be beneficial to ap...

  3. Analysis and testing of an integrated semi-active seat suspension for both longitudinal and vertical vibration control

    Bai, Xian-Xu; Jiang, Peng; Pan, Hui; Qian, Li-Jun

    2016-04-01

    An integrated semi-active seat suspension for both longitudinal and vertical vibration control is analyzed and tested in this paper. The seat suspension consists of a switching mechanism transforming both longitudinal and vertical motions into a rotary motion and a real-time damping-controllable system-a rotary magnetorheological (MR) damper working in pure shear mode and its corresponding control system. The switching mechanism employs the parallelogram frames as a motion guide which keeps the seat moving longitudinally and vertically. At the same time, both longitudinal and vertical motions are transformed into a reciprocating rotary motion that is transmitted to the rotary MR damper after an amplification by a gear mechanism. Both the longitudinal and vertical vibrations can be attenuated in real time through controlling the damping force (or torque) of the rotary MR damper. The mathematical model of the seat suspension system is established, simulated, and analyzed. The experimental test based on the test rig in Hefei University of Technology is implemented, and the results of simulation and experimental test are compared and analyzed.

  4. Comparing the cloud vertical structure derived from several methods based on measured atmospheric profiles and active surface measurements

    M. Costa-Surós

    2013-06-01

    Full Text Available The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, is an important characteristic in order to describe the impact of clouds in a changing climate. In this work several methods to estimate the cloud vertical structure (CVS based on atmospheric sounding profiles are compared, considering number and position of cloud layers, with a ground based system which is taken as a reference: the Active Remote Sensing of Clouds (ARSCL. All methods establish some conditions on the relative humidity, and differ on the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study these methods are applied to 125 radiosonde profiles acquired at the ARM Southern Great Plains site during all seasons of year 2009 and endorsed by GOES images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The overall agreement for the methods ranges between 44–88%; four methods produce total agreements around 85%. Further tests and improvements are applied on one of these methods. In addition, we attempt to make this method suitable for low resolution vertical profiles, which could be useful in atmospheric modeling. The total agreement, even when using low resolution profiles, can be improved up to 91% if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

  5. 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.

  6. 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.

  7. A method for calculating active feedback system to provide vertical position control of plasma in a tokamak

    Nizami Gasilov

    2007-04-01

    In designing tokamaks, the maintenance of vertical stability of plasma is one of the most important problems. Systems of the passive and active feedbacks are applied for this purpose. Role of the passive system consisting of a vacuum vessel and passive coils is to suppress fast MHD (magnetohydrodynamic) instabilities. The active feedback system is applied to control slow motions of plasma. The objective of the paper is to investigate two successive problems, solution of which allows to determine the possibility of controlling plasma motions. One of these is the problem of vertical stability under the assumption of ideal conductivity of plasma and passive stabilizing elements. The problem is solved analytically and on the basis of the obtained solution a criterion of MHD-stability is formulated. The other problem is connected with the control of plasma vertical position with active feedback system. Calculation of feedback control parameters is formulated as an optimization problem and an approximate method to solve the problem is suggested. Numerical simulations are performed with parameters of the T-15M tokamak in order to justify the suggested method.

  8. 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

  9. 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.

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

    Li, Ningyu; Su, Yumin

    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 kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis. PMID:27478363

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

    Ningyu Li

    2016-01-01

    Full Text Available 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 kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis.

  12. Active Blade Pitch Control for Straight Bladed Darrieus Vertical Axis Wind Turbine of New Design

    Chougule, Prasad; Nielsen, Søren R.K.; Basu, Biswajit

    As Development of small vertical axis wind turbines (VAWT) for urban use is becoming an interesting topic both within industry and academia. However, there are few new designs of vertical axis turbines which are customized for building integration. These are getting importance because they operate...... at low rotational speed producing very less noise during operation, although these are less efficient than Horizontal Axis Wind Turbines (HAWT). The efficiency of a VAWT has been significantly improved by H-Darrieus VAWT design based on double airfoil technology as demonstrated by the authors in a...... multiple stream tube method is used to determine the performance of the H-Darrieus VAWT. The power coefficient is compared with that of a fixed pitch and a variable pitch double airfoil blade VAWT. It is demonstrated that an improvement in power coefficient by 20% is achieved and the turbine could start at...

  13. On the solar activity variations of nocturnal F region vertical drifts covering two solar cycles in the Indian longitude sector

    Madhav Haridas, M. K.; Manju, G.; Pant, Tarun Kumar

    2015-02-01

    A comprehensive analysis of the seasonal and solar cycle variabilities of nighttime vertical drift over the Indian longitude sector is accomplished using ionosonde data located at the magnetic equatorial location, Trivandrum (8.5°N, 76.5°E). The analysis extends over a span of two decades (1988-2008). The representative seasonal variations based on the extensive data of nocturnal vertical drift during three different solar activity epochs is arrived at, for the first time. Seasonally, it is seen that maximum post sunset Vd is obtained in vernal equinox (VE), followed by autumnal equinox (AE), winter solstice (WS), and summer solstice (SS) for high and moderate solar epochs, while for low solar epoch, maximum Vd occurs in WS followed by VE, AE, and SS. Further, the role of sunset times at the magnetic conjugate points in modulating the time and magnitude of peak drifts during different solar epochs is ascertained. The equinoctial asymmetry in peak Vd during high and moderate solar epochs is another significant outcome of this study. The solar activity dependence of vertical drift for a wide range of solar fluxes has been quantified for all the seasons. In the present era of GPS-based communication and navigation, these are important results that give a better handle in understanding essential factors that impact equatorial ionospheric phenomena.

  14. 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)

  15. 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 ...

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Influence of solar activity on red sprites and on vertical coupling in the system stratosphere-mesosphere

    Tonev, Peter T.; Velinov, Peter I. Y.

    2016-04-01

    The positive downward propagating streamers of sprites are considered as factors of vertical coupling in middle atmosphere. Sprites are initiated in the lower ionosphere (at 75-85 km) and their streamers propagate in the mesosphere and upper stratosphere where the solar activity (SA) can have significant influence. The problem considered by us is whether sprites are sensitive to the solar activity. Different possible ways of such influence are considered. They concern: i) relations between solar activity and the occurrence of sprite-producing lightning discharges; ii) sensitivity of streamer inception to solar variability; iii) 11-year variations of conductivity in the night-time mesosphere and stratosphere during solar cycle due to modulation of the galactic cosmic ray flux by solar activity, which can lead to changes in sprite-driving electric fields, and therefore, in sprites. Accounting for the effects of sprites on minor constituents (in particular NOx), a link between SA level and the che^mical balance in the mesosphere and stratosphere is considered, as well. With respect to this we study by modeling the response of the sprite-driving electric fields to SA variations with the account to a complex of parameters of sprite-producing lightning discharges and atmospheric conductivity. The lightning-driven electric fields needed for streamer propagation show minor dependence on conductivity changes caused by variations in cosmic ray flux during a solar cycle. The long-term changes in sprite's lower boundary by different parameters of lightning discharges and atmospheric conductivity parameters are estimated. During solar minimum, of the vertical dimension of sprites increases by up to 1.5 km than those during solar maximum. We estimate also the effect of the reduction of conductivity in thunderclouds with respect to the adjacent air. Reduction of cloud conductivity by a factor of 5-10 leads to larger vertical dimension of sprites due to descending of the sprite

  1. 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

  2. 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.

  3. Accretion disc dynamo activity in local simulations spanning weak-to-strong net vertical magnetic flux regimes

    Salvesen, Greg; Armitage, Philip J; Begelman, Mitchell C

    2015-01-01

    Strongly magnetized accretion discs around black holes have attractive features that may explain enigmatic aspects of X-ray binary behaviour. The structure and evolution of these discs are governed by a dynamo-like mechanism, which channels part of the accretion power liberated by the magnetorotational instability (MRI) into an ordered toroidal magnetic field. To study dynamo activity, we performed three-dimensional, stratified, isothermal, ideal magnetohydrodynamic shearing box simulations. The strength of the self-sustained toroidal magnetic field depends on the net vertical magnetic flux, which we vary across almost the entire range over which the MRI is linearly unstable. We quantify disc structure and dynamo properties as a function of the initial ratio of mid-plane gas pressure to vertical magnetic field pressure, $\\beta_0^{\\rm mid} = p_{\\rm gas} / p_B$. For $10^5 \\geq \\beta_0^{\\rm mid} \\geq 10$ the effective $\\alpha$-viscosity parameter scales as a power-law. Dynamo activity persists up to and includin...

  4. 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...

  5. 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.

  6. 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

  7. 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 (2006-2009). Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal's vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving (ShD) during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in ShD mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives (NDD) during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving (DD) is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals. PMID:23087648

  8. Identification and radio vision of the vertical structure of the layers and wave activity in the atmoshere

    Alexander, Pavelyev; Kefei, Zhang; Vladimir, Gubenko; Erjiang, Fu; Chuan-Sheng, Wang; Yuei-An, Liou; Yuriy, Kuleshov

    2010-05-01

    Identification and radio vision of the vertical structure of the layers and wave activity in the atmosphere Alexander Pavelyev, Vladimir Gubenko Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino, Russia Kefei Zhang, Erjiang Fu and Chuan-Sheng Wang School of Mathematical and Geospatial Sciences, RMIT University, Melbourne, Australia Yuei-An Liou Center for Space and Remote Sensing Research (CSRSR), National Central University, Jhongli, Taiwan Yuriy Kuleshov National Climate Centre, Bureau of Meteorology, Melbourne, Australia From an analysis of the CHAMP (Challenging Minisatellite Payload, Germany) and the FORMOSAT-3/COSMIC (FORMOSA Satellite Constellation Observing Systems for Meteorology, Ionosphere, and Climate mission, USA -Taiwan) satellite data it follows that the second-order time derivative of the eikonal (eikonal acceleration) and the Doppler frequency shift are two most important parameters indispensable for the radio vision of layers in the atmosphere and the ionosphere. Measurements of the temporal evolution of the Doppler shift permit one to study the vertical structure of the atmosphere under the condition of its spherical symmetry. Analysis of the amplitude and phase of interrelated variations in the eikonal acceleration and radio-wave intensity permits one to detect and identify the layers in the atmosphere and ionosphere. Therefore the eikonal acceleration/intensity technique can be applied to separate the influence of layered structures from contributions of irregularities and turbulence in the atmosphere. In many cases the layered structures in the atmosphere indicate quasi-periodical altitude dependence that reveals their wave origin. The altitude profile of the vertical gradient of refractivity in the layered structures can be used to find the main characteristics of the internal wave activity with a global coverage. When the type of internal waves are not known, the height dependence of the vertical gradient

  9. Effect of soil deep tillage on root activity and vertical distribution

    Deep tillage (broke plough pan) and cultivation before winter coming (cut off some roots in shallow soil layer)could obviously affect the mass root activity of wheat and it's spatial distribution. Deep tillage improved the physical and chemical properties of the soil, so was the root living condition. Comparison with the CK (conventional tillage), the spatial distribution of root activity intend to deepen and the root activity in deep soil layer was stronger with the soil of deep tillage, which was beneficial to delay the senescence of plant and increase grain yield. It was also found that cultivation before winter coming could improve the mass root activity in subsoil layer (below 20 cm), and its effect was the same as that of deep tillage

  10. Flight Services and Aircraft Access: Active Flow Control Vertical Tail and Insect Accretion and Mitigation Flight Test

    Whalen, Edward A.

    2016-01-01

    This document serves as the final report for the Flight Services and Aircraft Access task order NNL14AA57T as part of NASA Environmentally Responsible Aviation (ERA) Project ITD12A+. It includes descriptions of flight test preparations and execution for the Active Flow Control (AFC) Vertical Tail and Insect Accretion and Mitigation (IAM) experiments conducted on the 757 ecoDemonstrator. For the AFC Vertical Tail, this is the culmination of efforts under two task orders. The task order was managed by Boeing Research & Technology and executed by an enterprise-wide Boeing team that included Boeing Research & Technology, Boeing Commercial Airplanes, Boeing Defense and Space and Boeing Test and Evaluation. Boeing BR&T in St. Louis was responsible for overall Boeing project management and coordination with NASA. The 757 flight test asset was provided and managed by the BCA ecoDemonstrator Program, in partnership with Stifel Aircraft Leasing and the TUI Group. With this report, all of the required deliverables related to management of this task order have been met and delivered to NASA as summarized in Table 1. In addition, this task order is part of a broader collaboration between NASA and Boeing.

  11. Fluid dynamics of flapping aquatic flight in the bird wrasse: three-dimensional unsteady computations with fin deformation.

    Ramamurti, Ravi; Sandberg, William C; Löhner, Rainald; Walker, Jeffrey A; Westneat, Mark W

    2002-10-01

    Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists, biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin, and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of

  12. More active vertical migration of 137 Cs towards the groundwater level within areas of intensive agricultural activities

    Effect of agricultural pollutants upon the rate of 137 Cs migration in soil profiles has been studied. To estimate changes in the radiocaesium migration capacity with the presence of high amounts of potassic fertilizers were applied within experimental plots with podzolic and peat-boggy soils. The results of layer-by layer soil and ground testing within experimental and untreated (without KCL) plots were used to estimate an increase of the diffusion coefficient and 137 Cs migration rate in these soils in the period from June to September. Experimental results obtained suggest that the soil section enrichment with potassium provides a several times increase of radiocaesium vertical migration along soil profiles towards the groundwater level

  13. 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

  14. 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 ...

  15. Efeito do Uso do Estabilizador Active Ankle System® na Altura do Salto Vertical em Jogadores de Voleibol Effect of the Use of the Active Ankle System Stabilizer in The Vertical Jump Height in Volleyball Players

    Marco Túlio Saldanha dos Anjos

    2009-10-01

    Full Text Available INTRODUÇÃO E OBJETIVO: Na prática do voleibol, as entorses de tornozelo representam 25 a 50% das lesões agudas. Medidas preventivas, como estabilizadores dinâmicos de tornozelo (EDT, são frequentemente utilizadas, porém, há controvérsias se esse dispositivo pode ou não interferir no desempenho esportivo. O objetivo deste estudo foi analisar o efeito do EDT Active Ankle System® (AAS na altura do salto vertical em jogadoras de voleibol. MÉTODOS: Selecionou-se uma amostra de conveniência de 14 atletas entre 14 e 18 anos de idade, do gênero feminino. Estas foram instruídas a saltar simulando o gesto esportivo do ataque e do bloqueio com e sem o EDT, sobre placas de contato conectadas a um computador portátil que, através de um programa, calculava a altura do salto vertical. Previamente, foi feito um estudo-piloto para determinação do coeficiente de correlação intraclasse para as quatro condições de teste (n = 4, no qual os valores encontrados foram: ataque com EDT, 0,95; ataque sem EDT, 0,76; bloqueio com EDT, 0,92; bloqueio sem EDT, 0,89. Os dados de altura de cada tipo de salto vertical nas condições com e sem EDT foram comparadas através de testes t de Student para amostras pareadas. RESULTADOS: Para um nível de significância de α = 0,05, não foi encontrada diferença significativa entre os saltos do ataque com o EDT (0,41 + 0,073m e sem o EDT (0,41 + 0,086m, p = 0,517. Também não foi encontrada diferença significativa para os saltos do bloqueio com o EDT (0,31 ± 0,048m e sem o EDT (0,32 ± 0,050m, p = 0,06. CONCLUSÃO: Os resultados do presente estudo apontam para não interferência do uso do EDT AAS no desempenho do salto vertical em atletas de voleibol.INTRODUCTION AND OBJECTIVES: In volleyball practice, ankle sprains represent 25 to 50% of the acute injuries. Preventive measures such as dynamic ankle bracing (DAB are very often used; however, there is controversy on whether this would affect athletic

  16. 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.

  17. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    Zirak, M. [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Moradlou, O. [Department of Chemistry, Faculty of Sciences, Alzahra University, P.O. Box 1993893973, Tehran (Iran, Islamic Republic of); Bayati, M.R. [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695-7907 (United States); Nien, Y.T. [Department of Materials Science and Engineering, National Formosa University, Huwei District, Taiwan (China); Moshfegh, A.Z., E-mail: moshfegh@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11555-9161, Tehran (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-8969, Tehran (Iran, Islamic Republic of)

    2013-05-15

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min{sup −1} under UV illumination and 0.007 min{sup −1} under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  18. On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells

    We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core–shell nanorods where the features were grown through a multistep procedure including sol–gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples were also studied using UV–vis spectrophotometry. It was found that the absorption edge of the CdS shell has a red shift when its thickness increases. Photocatalytic activity of the samples was examined by photodecomposition of methylene blue under UV and visible lights where the maximum reaction rate constant was found to be 0.012 min−1 under UV illumination and 0.007 min−1 under visible light. The difference in catalytic activities of the ZnO@CdS core–shell nanorods under UV and visible irradiations was explained based upon the electronic structure as well as the arrangement of the energy levels in the ZnO@CdS core–shells. It is shown that the structure and photocatalytic efficiency of the samples can be tuned by manipulating the SILAR variables.

  19. Development of active edge pixel sensors and four-side buttable modules using vertical integration technologies

    Macchiolo, A; Moser, H-G; Nisius, R; Richter, R H; Terzo, S; Weigell, P

    2014-01-01

    We present an R&D activity focused on the development of novel modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The modules consist of n-in-p pixel sensors, 100 or 200 $\\mu$m thick, produced at VTT (Finland) with an active edge technology, which considerably reduces the dead area at the periphery of the device. The sensors are interconnected with solder bump-bonding to the ATLAS FE-I3 and FE-I4 read-out chips, and characterized with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of $5\\times 10^{15}$ \

  20. Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments

    Behrendt, A.; de Beer, D.; Stief, P.

    2013-01-01

    The relative importance of two dissimilatory nitrate reduction pathways, denitrification (DEN) and dissimilatory nitrate reduction to ammonium (DNRA), was investigated in intact sediment cores from five different coastal marine field sites (Dorum, Aarhus Bight, Mississippi Delta, Limfjord...... reduction was clearly dominated by DEN (59-131% of the total NO3- reduced) rather than by DNRA, irrespective of the sedimentary inventories of electron donors such as organic carbon, sulfide, and iron. Highest ammonium production via DNRA, accounting for up to 8.9% of the total NO3- reduced, was found...... at a site with very high concentrations of total sulfide and NH4+ within and below the layer in which NO3- reduction occurred. Sediment from two field sites, one with low and one with high DNRA activity in the core incubations, was also used for slurry incubations. Now, in both sediments high DNRA activity...

  1. Development of active edge pixel sensors and four-side buttable modules using vertical integration technologies

    Macchiolo, A.; Andricek, L.; Moser, H.-G.; Nisius, R.; Richter, R. H.; Terzo, S.; Weigell, P.

    2014-11-01

    We present an R&D activity focused on the development of novel modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The modules consist of n-in-p pixel sensors, 100 or 200 μm thick, produced at VTT (Finland) with an active edge technology, which considerably reduces the dead area at the periphery of the device. The sensors are interconnected with solder bump-bonding to the ATLAS FE-I3 and FE-I4 read-out chips, and characterised with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of 5 ×1015neq /cm2. We will also report on the R&D activity to obtain Inter Chip Vias (ICVs) on the ATLAS read-out chip in collaboration with the Fraunhofer Institute EMFT. This step is meant to prove the feasibility of the signal transport to the newly created readout pads on the backside of the chips allowing for four side buttable devices without the presently used cantilever for wire bonding. The read-out chips with ICVs will be interconnected to thin pixel sensors, 75 μm and 150 μm thick, with the Solid Liquid Interdiffusion (SLID) technology, which is an alternative to the standard solder bump-bonding.

  2. Development of active edge pixel sensors and four-side buttable modules using vertical integration technologies

    Macchiolo, A., E-mail: Anna.Macchiolo@mpp.mpg.de [Max-Planck-Institut for Physics, Föhringer Ring 6, D-80805 Munich (Germany); Andricek, L. [Semiconductor Laboratory of the Max-Planck-Society, Otto Hahn Ring 6, D-81739 Munich (Germany); Moser, H.-G.; Nisius, R. [Max-Planck-Institut for Physics, Föhringer Ring 6, D-80805 Munich (Germany); Richter, R.H. [Semiconductor Laboratory of the Max-Planck-Society, Otto Hahn Ring 6, D-81739 Munich (Germany); Terzo, S.; Weigell, P. [Max-Planck-Institut for Physics, Föhringer Ring 6, D-80805 Munich (Germany)

    2014-11-21

    We present an R and D activity focused on the development of novel modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The modules consist of n-in-p pixel sensors, 100 or 200 μm thick, produced at VTT (Finland) with an active edge technology, which considerably reduces the dead area at the periphery of the device. The sensors are interconnected with solder bump-bonding to the ATLAS FE-I3 and FE-I4 read-out chips, and characterised with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of 5×10{sub 15}n{sub eq}/cm{sup 2}. We will also report on the R and D activity to obtain Inter Chip Vias (ICVs) on the ATLAS read-out chip in collaboration with the Fraunhofer Institute EMFT. This step is meant to prove the feasibility of the signal transport to the newly created readout pads on the backside of the chips allowing for four side buttable devices without the presently used cantilever for wire bonding. The read-out chips with ICVs will be interconnected to thin pixel sensors, 75 μm and 150 μm thick, with the Solid Liquid Interdiffusion (SLID) technology, which is an alternative to the standard solder bump-bonding.

  3. Interface Architecture Determined Electrocatalytic Activity of Pt on Vertically Oriented TiO2 Nanotubes

    R Rettew; N Allam; F Alamgir

    2011-12-31

    The surface atomic structure and chemical state of Pt is consequential in a variety of surface-intensive devices. Herein we present the direct interrelationship between the growth scheme of Pt films, the resulting atomic and electronic structure of Pt species, and the consequent activity for methanol electro-oxidation in Pt/TiO{sub 2} nanotube hybrid electrodes. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) measurements were performed to relate the observed electrocatalytic activity to the oxidation state and the atomic structure of the deposited Pt species. The atomic structure as well as the oxidation state of the deposited Pt was found to depend on the pretreatment of the TiO{sub 2} nanotube surfaces with electrodeposited Cu. Pt growth through Cu replacement increases Pt dispersion, and a separation of surface Pt atoms beyond a threshold distance from the TiO{sub 2} substrate renders them metallic, rather than cationic. The increased dispersion and the metallic character of Pt results in strongly enhanced electrocatalytic activity toward methanol oxidation. This study points to a general phenomenon whereby the growth scheme and the substrate-to-surface-Pt distance dictates the chemical state of the surface Pt atoms, and thereby, the performance of Pt-based surface-intensive devices.

  4. Development of active edge pixel sensors and four-side buttable modules using vertical integration technologies

    We present an R and D activity focused on the development of novel modules for the upgrade of the ATLAS pixel system at the High Luminosity LHC (HL-LHC). The modules consist of n-in-p pixel sensors, 100 or 200 μm thick, produced at VTT (Finland) with an active edge technology, which considerably reduces the dead area at the periphery of the device. The sensors are interconnected with solder bump-bonding to the ATLAS FE-I3 and FE-I4 read-out chips, and characterised with radioactive sources and beam tests at the CERN-SPS and DESY. The results of these measurements will be discussed for devices before and after irradiation up to a fluence of 5×1015neq/cm2. We will also report on the R and D activity to obtain Inter Chip Vias (ICVs) on the ATLAS read-out chip in collaboration with the Fraunhofer Institute EMFT. This step is meant to prove the feasibility of the signal transport to the newly created readout pads on the backside of the chips allowing for four side buttable devices without the presently used cantilever for wire bonding. The read-out chips with ICVs will be interconnected to thin pixel sensors, 75 μm and 150 μm thick, with the Solid Liquid Interdiffusion (SLID) technology, which is an alternative to the standard solder bump-bonding

  5. 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

  6. 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.

  7. How predation shaped fish: the impact of fin spines on body form evolution across teleosts.

    Price, S A; Friedman, S T; Wainwright, P C

    2015-11-22

    It is well known that predators can induce morphological changes in some fish: individuals exposed to predation cues increase body depth and the length of spines. We hypothesize that these structures may evolve synergistically, as together, these traits will further enlarge the body dimensions of the fish that gape-limited predators must overcome. We therefore expect that the orientation of the spines will predict which body dimension increases in the presence of predators. Using phylogenetic comparative methods, we tested this prediction on the macroevolutionary scale across 347 teleost families, which display considerable variation in fin spines, body depth and width. Consistent with our predictions, we demonstrate that fin spines on the vertical plane (dorsal and anal fins) are associated with a deeper-bodied optimum. Lineages with spines on the horizontal plane (pectoral fins) are associated with a wider-bodied optimum. Optimal body dimensions across lineages without spines paralleling the body dimension match the allometric expectation. Additionally, lineages with longer spines have deeper and wider body dimensions. This evolutionary relationship between fin spines and body dimensions across teleosts reveals functional synergy between these two traits and a potential macroevolutionary signature of predation on the evolutionary dynamics of body shape. PMID:26559954

  8. 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

  9. 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...

  10. Vertical and temporal variability of DMSP lyase activity in a coccolithophorid bloom in the northern North Sea

    Steinke, Michael; Malin, Gill; Gibb, Stuart W.; Burkill, Peter H.

    The climatically relevant trace gas dimethyl sulphide (DMS) is produced within the microbial food-web from the algal metabolite dimethylsulphoniopropionate (DMSP). The presence of DMSP lyase isozymes is necessary for this process. Measurements of in vitro DMSP lyase activity (DLA) were conducted in the northern North Sea in June 1999 in order to investigate the vertical and temporal variability of activity in a Lagrangian time-series process study. DLA ranged from 4 to 207 nM h -1, with maximum values close to the surface and between 30 and 50 m depth. DLA increased towards the surface relative to chlorophyll a, as did the non-photosynthetic but photoprotective pigment diadinoxanthin, DMS and dissolved dimethylsulphoxide, a likely oxidation product of DMS. These observations support the hypothesis that DMSP lyases can be affected by irradiance levels, and that DMSP and its cleavage products could be involved in scavenging oxygen radicals; hence, they may function as antioxidants in marine algae. Linear regression analysis of our field data showed reduced biomass of some oligotrich and non-oligotrich ciliates at higher levels of DLA, a finding that could be supportive of a role for phytoplankton DMSP lyases in chemical defence.

  11. Comparing vertical profiles of natural tracers in the Williston Basin to estimate the onset of deep aquifer activation

    Hendry, M. Jim; Harrington, Glenn A.

    2014-08-01

    Comparing high-resolution depth profiles of different naturally occurring environmental tracers in aquitards should yield consistent and perhaps complementary information about solute transport mechanisms and the timing of major hydrogeological and climatological events. This study evaluated whether deep, continuous profiles of aquitard pore water chloride concentration could provide further insight into the paleohydrology of the Williston Basin, Canada, than possible using high-resolution depth profiles of stable H/O isotopes of water (δ18O, δ2H). Pore water samples were obtained from extracts of cores taken over 392 m of the thick Cretaceous shale aquitard. Water samples were also collected from wells installed in the underlying regional sandy aquifer (Mannville Group; 93 m thick) and from seepage inflows into potash mine shafts (to 825 m below ground). Numerical modeling of the 1-D vertical Cl- profile supported diffusion dominated solute transport in the shales. The modeling also showed a similar time frame for development of the Cl- profile prior to activation of the aquifer as determined from the δ18O profile (20-25 Ma); however, it provided a significantly longer and potentially better-constrained time frame for evolution of the profile during the activation phase of the aquifer (0.5-1 Ma). The dominant paleoevent reflected in present-day profiles of both tracers is the introduction of glaciogenic meteoric water to the Mannville aquifer underlying the shale during the Pleistocene. The source area of this water remains to be determined.

  12. High electrocatalytic activity of Pt-Pd binary spherocrystals chemically assembled in vertically aligned TiO2 nanotubes.

    Lei, Yanzhu; Zhao, Guohua; Tong, Xili; Liu, Meichuan; Li, Dongming; Geng, Rong

    2010-01-18

    To obtain noble metal catalysts with high efficiency, long-term stability, and poison resistance, Pt and Pd are assembled in highly ordered and vertically aligned TiO(2) nanotubes (NTs) by means of the pulsed-current deposition (PCD) method with assistance of ultrasonication (UC). Here, Pd serves as a dispersant which prevents agglomeration of Pt. Thus Pt-Pd binary catalysts are embed into TiO(2) NTs array under UC in sunken patterns of composite spherocrystals (Sps). Owing to this synthesis method and restriction by the NTs, the these catalysts show improved dispersion, more catalytically active sites, and higher surface area. This nanotubular metallic support material with good physical and chemical stability prevents catalyst loss and poisoning. Compared with monometallic Pt and Pd, the sunken-structured Pt-Pd spherocrystal catalyst exhibits better catalytic activity and poison resistance in electrocatalytic methanol oxidation because of its excellent dispersion. The catalytic current density is enhanced by about 15 and 310 times relative to monometallic Pt and Pd, respectively. The poison resistance of the Pt-Pd catalyst was 1.5 times higher than that of Pt and Pd, and they show high electrochemical stability with a stable current enduring for more than 2100 s. Thus, the TiO(2) NTs on a Ti substrate serve as an excellent support material for the loading and dispersion of noble metal catalysts. PMID:19924757

  13. 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

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

    Du Xueping

    2014-01-01

    Full Text Available A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90°, 60 °, 45°, and 30° are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90° has the worst performance while 45° and 30° has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60°, while the best performance occurred at 45° and 90° at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

  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. 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...

  4. 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...

  5. A review of vertical coupling in the Atmosphere-Ionosphere system: Effects of waves, sudden stratospheric warmings, space weather, and of solar activity

    Yiğit, Erdal; Koucká Knížová, Petra; Georgieva, Katya; Ward, William

    2016-04-01

    This brief introductory review of some recent developments in atmosphere-ionosphere science is written for the "Vertical Coupling Special Issue" that is motivated by the 5th IAGA/ICMA/SCOSTEP Workshop on Vertical Coupling in the Atmosphere-Ionosphere System. Basic processes of vertical coupling in the atmosphere-ionosphere system are discussed, focusing on the effects of internal waves, such as gravity waves and solar tides, sudden stratospheric warmings (SSWs), and of solar activity on the structure of the atmosphere. Internal waves play a crucial role in the current state and evolution of the upper atmosphere-ionosphere system. SSW effects extend into the upper atmosphere, producing changes in the thermospheric circulation and ionospheric disturbances. Sun, the dominant energy source for the atmosphere, directly impacts the upper atmosphere and modulates wave-induced coupling. The emphasis is laid on the most recent developments in the field, while giving credits to older works where necessary. Various international activities in atmospheric vertical coupling, such as SCOSTEP's ROSMIC project, and a brief contextual discussion of the papers published in the special issue are presented.

  6. Effects of thin fin on natural convection in porous triangular enclosures

    Varol, Yasin [Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235 (United States); Oztop, Hakan F. [Department of Mechanical Engineering, Firat University, TR-23119, Elazig (Turkey); Varol, Asaf [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26505 (United States)

    2007-10-15

    A two-dimensional solution of natural convection in solid adiabatic thin fin attached to porous right triangular enclosures has been analyzed numerically. The vertical wall of the enclosure is insulated while the bottom and the inclined walls are isothermal. The temperature of the bottom wall is higher than the temperature of the inclined wall. Governing equations, which are written using Darcy model, are solved via the finite difference technique. The Successive Under Relaxation (SUR) method was used to solve linear algebraic equations. Dimensionless location of the thin fin from 0.2 to 0.6, the aspect ratio of triangular enclosure from 0.25 to 1, Rayleigh number from 100 to 1000 and the dimensionless height of the fin from 0.1 to 0.4 are used as governing parameters that are effective on heat transfer and fluid flow. Results for the mean Nusselt number, velocity profiles, the contour maps of the streamlines and isotherms are presented. It is observed that the thin fin can be used as a passive control element for flow field, temperature distribution and heat transfer. (author)

  7. Fabrication of polymer-based optical microsystem arrays suited for the active focusing of vertical laser diodes

    We present a low-cost fabrication technique of a polymer-based micro-optical-electrical-mechanical systems (MOEMS) suited for the dynamic focusing of VCSELs (vertical-cavity surface-emitting lasers). A simple method based on an SU(8) double exposure is proposed for the collective integration of small footprint transparent suspended membrane arrays on vertical laser diodes. We demonstrate that this kind of MOEMS can provide under thermal actuation a vertical displacement of around 0.2 µm W−1 over a maximal range of 8 µm. As a wide range of initial gaps between the membrane and the laser source can be chosen, this approach opens new insights into the dynamic control of the VCSEL beam waist position as well as for tunable VCSEL fabrication. (paper)

  8. Supersonic aerodynamic characteristics of conformal carriage monoplanar circular missile configurations with low-profile quadriform tail fins

    Blair, A. B., Jr.

    1990-01-01

    Wind tunnel tests were conducted on monoplanar circular missile configurations with low-profile quadriform tail fins to provide an aerodynamic data base to study and evaluate air-launched missile candidates for efficient conformal carriage on supersonic-cruise-type aircraft. The tests were conducted at Mach numbers from 1.70 to 2.86 for a constant Reynolds number per foot of 2,000,000. Selected test results are presented to show the effects of tail-fin dihedral angle, wing longitudinal and vertical location, and nose-body strakes on the static longitudinal and lateral-directional aerodynamic stability and control characteristics.

  9. 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)

  10. 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.

  11. 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.

  12. Seasonal migration, vertical activity and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides (Walbaum) in West Greenland waters

    Boje, Jesper; Neuenfeldt, Stefan; Sparrevohn, Claus Reedtz;

    2014-01-01

    little is known about its behavior and habitat characteristics. We tagged adult Greenland halibut in the waters off Ilulissat with electronic data storage tags that collected information on depth, temperature, and time. Although clear differences between individuals in migration and vertical behavior...

  13. 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.

  14. A review of vertical coupling in the Atmosphere-Ionosphere system: Effects of waves, sudden stratospheric warmings, space weather, and of solar activity

    Yigit, E.; Koucká Knížová, Petra; Georgieva, K.; Ward, W.

    2016-01-01

    Roč. 141, April (2016), s. 1-12. ISSN 1364-6826 R&D Projects: GA ČR(CZ) GA15-24688S; GA MŠk(CZ) LG13042 Institutional support: RVO:68378289 Keywords : atmosphere–ionosphere * vertical coupling * gravity waves * tides * space weather * solar activity Impact factor: 1.474, year: 2014 http://www.sciencedirect.com/science/article/pii/S1364682616300426

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. An experimental study of flow boiling in a rectangular channel with offset strip fins

    An experimental study on saturated flow boiling heat transfer of R113 was performed in a vertical rectangular channel with offset strip fins. Two-phase pressure gradients and boiling heat transfer coefficients in an electrically heated test section were measured for the quality range of 0-0.6, mass flux range of 17-43 kg/m2 s and heat flux of 500-3000 W/m2. Two-phase frictional multiplier was determined as a function of Martinelli parameter. The two-phase forced convective component of the local boiling heat transfer coefficient was found to be well correlated with the Reynolds number factor. A superposition method for the flow boiling heat transfer coefficient that included the contribution of saturated nucleate boiling was verified also for flow boiling in a channel with offset strip fins. The predictions of local flow boiling heat transfer coefficients were found to be in good agreement with experimental data

  3. 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.

  4. NET vertical stability

    The elongated cross-section of the plasma in NET leads to vertical positional instability so that a passive and active stabilizing system is required. The passive action is performed essentially by the segmented first wall, while the active action is performed by two feedback driven toroidal bars. The performance of such a system is presented for a reference case, as well as a sensitivity analysis with respect to some parameters. (author)

  5. NET vertical stability

    The elongated cross-section of the plasma in NET leads to vertical positional instability so that a passive and active stabilizing system is required. The passive action is performed essentially by the segmented first wall, while the active action is performed by two feedback driven toroidal bars. The performance of such a system is presented here for a reference case, as well as a sensitivity analysis with respect to some parameters

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. Continuous on-line calibration of diffusive soil-atmosphere trace gas transport using vertical 220Rn- and 222Rn-activity profiles

    Continuous monitoring of 220Rn- and 222Rn-activities above and below the soil surface combined with sporadic direct 222Rn-flux measurements is used to quantify diffusive trace gas transport in the air-filled pore space of soil, through the soil-atmosphere interface and in the lowest layers of the atmosphere. In a calm night, 222Rn-activities above the surface first build-up near the ground (z 222Rn-flux from activity profiles measured in soil gas, (2) from direct flux determinations and (3) using information about atmospheric diffusion parameters from 220Rn-activities measured near the surface it is possible to model the temporal evolution of the vertical 222Rn-profiles in a night with stable weather and constant soil conditions. The system operates automatically for extended periods of time in the field enabling a better understanding of transport processes in response to changing environmental conditions (wind, rain, soil humidity). (orig.)

  15. 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...

  16. 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...

  17. 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

  18. 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...

  19. 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.

  20. Effects of Warm-Up on Vertical Jump Performance and Muscle Electrical Activity Using Half-Squats at Low and Moderate Intensity

    Konstantinos Sotiropoulos; Ilias Smilios; Marios Christou; Karolina Barzouka; Angelos Spaias; Helen Douda; Tokmakidis, Savvas P.

    2010-01-01

    The purpose of this study was to determine the effects of a specific warm-up using half-squats at low and moderate intensity on vertical jump performance and electromyographic activity of the thigh muscles. The subjects were 26 men who were divided into a low intensity group (LIG; n = 13) and a moderate intensity group (MIG; n = 13). The LIG performed a specific warm-up protocol that included the explosive execution of half-squats with loads 25 and 35% of the one repetition maximum (1RM) and ...

  1. Vertically aligned CNT growth on a microfabricated silicon heater with integrated temperature control—determination of the activation energy from a continuous thermal gradient

    Engstrøm, Daniel Southcott; Rupesinghe, Nalin L; Teo, Kenneth B K; Milne, William I; Bøggild, Peter

    2011-01-01

    Silicon microheaters for local growth of a vertically aligned carbon nanotube (VACNT) were fabricated. The microheaters had a four-point-probe structure that measured the silicon conductivity variations in the heated region which is a measure of the temperature. Through FEM simulations the...... temperature was determined on the entire microheater structure, and the simulated temperatures were verified by micro-Raman spectroscopy. The microheaters provided a temperature gradient along which VACNTs were grown at 575–800 °C simultaneously. The VACNT growth activation energy was determined to 0.86 e...

  2. Simultaneous determination of in situ vertical transitions of color, pore-water metals, and visualization of infaunal activity in marine sediments

    Teal, L.; R. Parker; Fones, Gary; Solan, M.

    2009-01-01

    The vertical color transition from brown to gray-green in marine sediments is linked to the Fe redox boundary and is commonly used as a proxy for biogeochemical state. We combine time-lapse sediment profile imaging with diffusive gradient thin (DGT) gels to obtain simultaneous in situ measurements of sediment color profiles, pore-water Fe and Mn profiles, and qualitative estimates of faunal activity at the Oyster Ground and North Dogger (North Sea). Analysis of Fe and Mn profiles using genera...

  3. Light coupling between vertical III-As nanowires and planar Si photonic waveguides for the monolithic integration of active optoelectronic devices on a Si platform.

    Giuntoni, Ivano; Geelhaar, Lutz; Bruns, Jürgen; Riechert, Henning

    2016-08-01

    We present a new concept for the optical interfacing between vertical III-As nanowires and planar Si waveguides. The nanowires are arranged in a two-dimensional array which forms a grating structure on top of the waveguide. This grating enables light coupling in both directions between the components made from the two different material classes. Numerical simulations show that this concept permits a light extraction efficiency from the waveguide larger than 45% and a light insertion efficiency larger than 35%. This new approach would allow the monolithic integration of nanowire-based active optoelectronics devices, like photodetectors and light sources, on the Si photonics platform. PMID:27505805

  4. 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.

  5. 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...

  6. 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

  7. 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...

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Three-dimensional transient cooling simulations of a portable electronic device using PCM (phase change materials) in multi-fin heat sink

    Transient three-dimensional heat transfer numerical simulations were conducted to investigate a hybrid PCM (phase change materials) based multi-fin heat sink. Numerical computation was conducted with different amounts of fins (0 fin, 3 fins and 6 fins), various heating power level (2 W, 3 W and 4 W), different orientation tests (vertical/horizontal/slanted), and charge and discharge modes. Calculating time step (0.03 s, 0.05 s, and 0.07 s) size was discussed for transient accuracy as well. The theoretical model developed is validated by comparing numerical predictions with the available experimental data in the literature. The results showed that the transient surface temperatures are predicted with a maximum discrepancy within 10.2%. The operation temperature can be controlled well by the attendance of phase change material and the longer melting time can be conducted by using a multi-fin hybrid heat sink respectively. -- Highlights: → Electronic device cooling use phase change materials. → N-eicosane is adapted as phase change materials. → Present surface transient temperatures prediction error is within 10.2%. → Hybrid PCM-heat sink system provides stable operation temperature. → Orientation effects show independent on the phase change performance.

  15. 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.

  16. 77 FR 43063 - Affirmation of Vertical Datum for Surveying and Mapping Activities for the Territory of Puerto Rico

    2012-07-23

    ... Activities for the Territory of Puerto Rico AGENCY: National Geodetic Survey (NGS), National Ocean Service... National Ocean Service (NOS), National Geodetic Survey (NGS), has completed the definition and... control monuments is available in digital form, from the NGS Web site:...

  17. Experimental Investigation of the Effect of Spacing between Vertical Plates on the Development of a Thermal Plume from an Active Block

    Taoufik Naffouti

    2015-01-01

    Full Text Available In this paper, an experimental investigation was conducted to analyze the effect of spacing between vertical plates of a parallelepipedic canal on the average thermal and dynamic fields of a thermal plume. To carry out this study, we placed at the laboratory a rectangular heat block at the entry of a vertical canal open at the ends. The internal walls of the plates are heated uniformly by Joule effect and by thermal radiation emitted by active source. The heating of walls creates a thermosiphon flow which interacts with the plume inside canal. Four dimensionless spacing between the plates 1.25 ≤ e* ≤ 30 are considered. It is found that the spacing is the most important geometrical parameter affecting the thermal and dynamical behavior of the flow. Using visualization by laser plan and hot wire probe, flow structure evolves in two zones for smallest and largest spacing while a supplementary zone near heat source is observed for an intermediate spacing. The variation of flow rate and energy transported by the fluid shows the existence of an optimum spacing where the propagation of plume flow is more accelerated.

  18. Vertical Integration, innovation and foreclosure

    Allain, Marie-Laure; Chambolle, Claire; Rey, Patrick; Ecole Polytechnique Chaire d'économie

    2010-01-01

    This paper studies the potential effects of vertical integration on downstream firms’incentives to innovate. Interacting efficiently with a supplier may require information exchanges, which raises the concern that sensitive information may be disclosed to rivals. This may be particularly harmful in case of innovative activities, as it increases the risk of imitation. We show that vertical integration exacerbates this threat of imitation, which de facto degrades the integrated supplier’s abili...

  19. The Effect of a Piezoelectric Fan on Forced Air Heat Transfer in a Pin-Fin Heat Sink

    Tzer-Ming Jeng

    2015-02-01

    Full Text Available An investigation was carried out on the effect of airflow from the blade of a piezoelectric fan on the main cooling airflow across a pin-fin heat sink. The study considered the respective orientation and distances between the piezoelectric blade and the heat sink in a rectangular channel where the airflow was uniform and axial. Three different pin-fin heat sinks with in-line pin-fin arrays were used: 5´5, 7´7 and 9´9. Variable parameters included the Reynolds number of the main airflow and the relative position of the piezoelectric blade and the heat sink. The results showed that the smaller the horizontal distance between the blade and the heat sink, or the greater the vertical distance between the piezoelectric blade and the channel floor, the better the total heat transfer enhancement. Of the three heat sinks used, the 9´9 unit coupled with transverse oscillation of the piezoelectric blade had a slightly higher heat-transfer ratio enhancement. The heat-transfer enhancement ratio Nu/Nu0 (Nu0 is the Nusselt number of the system without the piezoelectric blade will gradually approach 1 with an increase of the Reynolds number of the main flow. At ReL=1200, and with the assistance of the piezoelectric blade, the maximum value of Nu/Nu0 for the 9´9 pin-fin heat sink exceeded 2.

  20. Shaping and reproduction patterns of power elites in former Yugoslavia II: Channels of vertical mobility: Education and political activity

    Miladinović Slobodan M.

    2003-01-01

    Full Text Available In the second part of this paper are analyzed effecting of main channels of social mobility for ascent on elite's positions in Serbia and Croatia. Special attention was paid to education and political activity. Survey data says that the patterns of ideological desirable social origin were developed in pattern of ideological desirable developing way of building individual career of members of power elite's across the time. Special importance in that process had high education acquirement. Political activity was necessary follower in the way of advance to the highest social positions. There was used log-linear analyze (hierarchical method because finding statistical importance between presented factors of education and political activity. Thanks to this method we can see details of complex relations of interdependence of this factors.

  1. 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

  2. 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....

  3. 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...

  4. Experimental investigation of the effects of orientation angle on heat transfer performance of pin-finned surfaces in natural convection

    Natural convection heat transfer in air from a pin-finned surface is investigated experimentally by considering the effect of radiation heat transfer. The plate was oriented as the pin arrays facing either downwards or upwards from vertical axis with different angles and the experiments were performed for different values of heater power input. From the results of the experiments it is observed that the pin fins increase the heat transfer considerably when compared to the unpinned surface. The upfacing pins are more enhancing heat transfer than the downfacing pins and the enhancement is decreasing with increasing orientation angle from the vertical axis. -- Research highlights: → Effect of orientation in free convection heat transfer from a pin-finned surface. → The upfacing pins are more enhancing heat transfer than the downfacing pins. → Radiation view factor is calculated by a modular analysis. → The radiation is comparable to free convection as not to be neglected. → The radiative part is 25-40% and increases for low heat transfer rates.

  5. Influence of in situ biological activity on the vertical profile of pre-emergence herbicides in sediment

    Devault, Damien A.; Delmotte, Sébastien; Merlina, Georges; Lim, Puy; Gérino, Magali; Pinelli, Eric

    2009-01-01

    The in situ effect of biological activity on herbicide degradation was studied in sediment. Early diagenesis indicators of organic matter (OM) was selected to provide information on the presence and the kinetics of the various biotic and abiotic processes involved in the degradation of fresh organic matter, the vector of herbicides in sediment. Two tandem-coring samples were taken in the Malause reservoir, one in the hyperoxic zone (Tarn confluence, MT core) and the other in the central part,...

  6. Thermally optimum spacing of vertical, natural convection cooled, parallel plates

    Bar-Cohen, A.; Rohsenow, W. M.

    Vertical two-dimensional channels formed by parallel plates or fins are a frequently encountered configuration in natural convection cooling in air of electronic equipment. In connection with the complexity of heat dissipation in vertical parallel plate arrays, little theoretical effort is devoted to thermal optimization of the relevant packaging configurations. The present investigation is concerned with the establishment of an analytical structure for analyses of such arrays, giving attention to useful relations for heat distribution patterns. The limiting relations for fully-developed laminar flow, in a symmetric isothermal or isoflux channel as well as in a channel with an insulated wall, are derived by use of a straightforward integral formulation.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  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. 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...

  13. HCl and ClO in activated Arctic air; first retrieved vertical profiles from TELIS submillimetre limb spectra

    A. de Lange

    2012-02-01

    Full Text Available The first profile retrieval results of the Terahertz and submillimeter Limb Sounder (TELIS balloon instrument are presented. The spectra are recorded during a 13-h balloon flight on 24 January 2010 from Kiruna, Sweden. The TELIS instrument was mounted on the MIPAS-B2 gondola and shared this platform with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS and the mini-Differential Optical Absorption Spectroscopy (mini-DOAS instruments. The flight took place within the Arctic vortex at an altitude of ≈34 km in chlorine activated air, and both active (ClO and inactive chlorine (HCl were measured over an altitude range of respectively ≈16–32 km and ≈10–32 km. In this altitude range, the increase of ClO concentration levels during sunrise has been recorded with a temporal resolution of one minute. During the daytime equilibrium, a maximum ClO level of 2.1 ± 0.3 ppbv has been observed at an altitude of 23.5 km. This equilibrium profile is validated against the ClO profile by the satellite instrument Microwave Limb Sounder (MLS aboard EOS Aura. HCl profiles have been determined from two different isotopes – H35Cl and H37Cl – and are also validated against MLS. The precision of all profiles is well below 0.01 ppbv and the overall accuracy is therefore governed by systematic effects. The total uncertainty of these effects is estimated to be maximal 0.3 ppbv for ClO around its peak value at 23.5 km during the daytime equilibrium, and for HCl it ranges from 0.05 to 0.4 ppbv, depending on altitude. In both cases the main uncertainty stems from a largely unknown non-linear response in the detector.

  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. 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...

  17. 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.

  18. 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.

  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. Seasonal and altitudinal variations on adaptation, growth and testicular activity of Baladi goats with vertical transhumance in Eastern Mediterranean

    The effects of transhumance on body growth and adaptation parameters in theBaladi goat, and testicular activity in bucks were studied over a period of one year. Thirty two animals were allocated to 4 similar groups according to age (100 days for 8 male and 8 female kids, and 3-4 years for 8 bucks and 8 does) and sex. Goats were raised in a coastal pasture area for the winter period (WP), then transhumed towards a mountainous area in May for the summer period (SP). Every 21 days, animals were weighed and monitored for a whole day to estimate the distance travelled; four does and four bucks were followed for two successive days to evaluate the nature of the plants grazed by direct observation. Four summer and two winter collections of these plants were subjected to proximate analysis; Respiration and heart rates were recorded every two hours between 6:00 a.m. and 6:00 p.m.; Testicular volume and semen quality were also measured. Animals traveled 1 km/h in summer period and 0.8 km/h in winter. Herbaceous plants formed 95% of the plants grazed in SP and ligneous plants formed the majority of the plants ingested (80 to 95%) in WP. Protein percentages decreased from 15.2 to 8.6% between the beginning and the middle of the SP whereas it was around 11% in WP. Weight gain was greater during SP in comparison to WP except for bucks (12, 7.6, 4.2 and -3.3 kg vs. 3.4,1.8, -7.5 and 3.3 kg for male and female goat kids, does and bucks, respectively). Respiration and heart rates showed adaptation of animals to walking long distances in both zones, stabilizing respectively at 47-50 breaths/min and 83-90 beats/min after a 6 km walk. Decrease in semen concentration was observed at the end of the animal's stay in each zone, with values between 3.1 and 3.7 spermatozoa x 109/ml vs. 1.7and 2.7 spermatozoa x 109/ml in SP and WP, respectively. The volume varied between 1.0 ±0.2 and 1.6 ± 0.4 ml in SP, and decreased to 0.6 ± 0.3 ml in WP. Transhumance is thus beneficial for only two

  1. 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...

  2. 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.

  3. 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

  4. Boiling heat transfer of refrigerant R-21 in upward flow in plate-fin heat exchanger

    Kuznetsov, V. V.; Shamirzaev, A. S.

    2015-11-01

    The article presents the results of experimental investigation of boiling heat transfer of refrigerant R-21 in upward flow in a vertical plate-fin heat exchanger with transverse size of the channels that is smaller than the capillary constant. The heat transfer coefficients obtained in ranges of small mass velocities and low heat fluxes, which are typical of the industry, have been poorly studied yet. The characteristic patterns of the upward liquid-vapor flow in the heat exchanger channels and the regions of their existence are detected. The obtained data show a weak dependence of heat transfer coefficient on equilibrium vapor quality, mass flow rate, and heat flux density and do not correspond to calculations by the known heat transfer models. A possible reason for this behavior is a decisive influence of evaporation of thin liquid films on the heat transfer at low heat flux.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Development of an active vertical vibration control system for high speed railway vehicles; Jogekei active seishin seigyo sochi no kaihatsu (300X Shinkansen shiken sharyo deno soko shiken kekka)

    Shirai, S.; Otsuka, T. [Central Japan Railway Company, Nagoya (Japan); Nishi, Y.; Matsushima, H.; Danbata, K. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1999-09-15

    With an objective to improve riding comfort in the 300X system Shinkansen vehicle, development has been made on an active vibration control system which gives force to the vehicle body forcibly by a hydraulic actuator to suppress vertical vibration. The H {infinity} control was used in designing the controller. The controller to control vertical translation and pitch vibration in the vehicle body controls frequency in the vicinity of about 1 Hz being resonant frequency of a suspension system. However, it does not control frequency band of 8 to 9 Hz being resonant frequency of the vehicle bending vibration. In turn, the controller to control the vehicle bending vibration controls frequency band of 8 to 9 Hz only. This allows the interference to be ignored nearly completely. As a result of the stationary test, it was verified that the vibration can be reduced by the active vibration control system also on the vehicle bending vibration, which had conventionally been handled by improving rigidity of the vehicle or by turning the bogie spring and damper systems. Good result has also been obtained from a driving test using test vehicles. (NEDO)

  10. 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.

  11. 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.

  12. 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

  13. 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)

  14. The role of post-sunset vertical drifts at the equator in predicting the onset of VHF scintillations during high and low sunspot activity years

    S. Tulasi Ram

    2006-07-01

    Full Text Available The day-to-day variability in the occurrence of ionospheric scintillations, which are of serious concern in the trans-ionospheric communications, makes their prediction still a challenging problem. This paper reports on a systematic study in quantitatively identifying the precursors responsible, such as pre-reversal E×B drift velocity, geo-magnetic activity index (Kp and the Equatorial Ionization Anomaly (EIA gradient, for the onset of VHF scintillations over a low-latitude station, Waltair (20° N dip, during high (2001 and low (2004 sunspot activity years. The percentage of occurrences of VHF scintillations over Waltair show a good correlation with the monthly mean post-sunset vertical drift velocities at the equator, during both the high and low sunspot activity years. During the days on which intense (>10 dB scintillations occur, the ionization anomaly gradient (dN/dL, measured from ionosonde data of an equatorial (Trivandrum, 0.9° N dip and an off-equatorial station (Waltair, 20° N dip shows an enhancement in the gradient prior to the onset of the scintillations. However, this enhancement is not seen on days when the scintillations are weak (<10 dB or absent. The day-to-day post sunset enhancement in the E×B drift is found to decrease with increasing Kp-index and this decrease is more prominent in the equinoxes, less in winter and insignificant in the summer months. On a day-to-day basis, it is found that the value of the upward drift velocity at the equator should be ≥30 m/s for the onset of strong scintillations over Waltair for magnetically quiet days with average Kp≤2 (6 h prior to the local sunset during the high sunspot year, 2001. This threshold value of the upward drift reduces to 20 m/s with the decrease in the sunspot activity during 2004. Further, these conditions for the onset of intense scintillations is well defined in equinoxes, less in

  15. 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...

  16. 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.

  17. Treinamento de força com uso de correntes e potencialização pós-ativação do salto vertical Entrenamiento de fuerza con cadenas y la potenciación post-activación del salto vertical Chain resistance training and vertical jump post-activation potentiation

    Jéderson Nunes

    2012-12-01

    Full Text Available A Potencialização Pós-Ativação (PPA é estratégia para melhora do desempenho com uso de carga fixa (RF, definida no ponto de falha mecânica (PFM. Por outro lado, o uso de correntes (CRT é estímulo com resistência variável (RV. Assim, objetivou-se avaliar os efeitos do CRT na altura e tempo de voo do salto vertical com contramovimento (CMJ. A partir de estudo de intervenção, 15 sujeitos foram avaliados quanto à carga máxima no agachamento (1RM e altura CMJ. Após isto, executaram três tipos de intervenções: i RF com 85% de 1RM; ii RV com 85% de 1RM posicionado no PFM (RV-TF e, iii RV com 85% de 1RM posicionado na maior extensão dos joelhos (RV-TV. Observou-se incremento do CMJ para RV-TF e RV-TV, mas não para RF. Conclui-se que houve PPA com os dois estímulos de CRT.La potenciación post-activación (PAP es estrategia para mejorar el rendimiento, utilizando una carga fija (RF, que se define en el punto de falla mecánica (PFM. Además, el uso de cadenas (CRT es estimulo con resistencia variable (RV. Así, el objetivo fue evaluar los efectos de la CRT en el salto vertical con contramovimiento (CMJ. Con estudio de intervención, 15 sujetos fueron evaluados acerca de la carga máxima en la sentadilla (1RM y altura en el CMJ. Después de eso, se realizaron tres tipos de intervenciones: i RF con el 85% de 1RM; ii RV con el 85% de 1RM en el PFM (RV-TF, y iii la RV en 1RM 85% situado en la mayor extensión de las rodillas (RV-TV. Se observó aumento de lo CMJ para RV-TF y RV-TV, pero no para la RF. Se concluye que existe PPA con los dos estímulos de RV.The Post-Activation Potentiation (PAP is a strategy to improve performance, using a fixed load (RF, defined at the sticking point (PFM. Moreover, the use of chains (CRT is an effort with variable resistance (RV. Thus, the objective was to evaluate the effects of CRT in the countermovement jump (CMJ. With an intervention study, 15 subjects were evaluated for the maximum squat load (1

  18. 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.

  19. 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.

  20. Estimated errors in vertical bar Vcd vertical bar / vertical bar Vcs vertical bar from semileptonic D decays

    We estimate statistical and systematic errors in the extraction of the CKM ratio vertical bar Vcd vertical bar / vertical bar Vcs vertical bar from exclusive D-meson semileptonic decays using lattice QCD and anticipated new experimental results

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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

  9. 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)

  10. 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 ...

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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)

  16. 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)

  17. Strategic Inventories in Vertical Contracts

    Krishnan Anand; Ravi Anupindi; Yehuda Bassok

    2008-01-01

    Classical reasons for carrying inventory include fixed (nonlinear) production or procurement costs, lead times, nonstationary or uncertain supply/demand, and capacity constraints. The last decade has seen active research in supply chain coordination focusing on the role of incentive contracts to achieve first-best levels of inventory. An extensive literature in industrial organization that studies incentives for vertical controls largely ignores the effect of inventories. Does the ability to ...

  18. Regeneración ósea guiada para el aumento vertical del reborde alveolar Guided osseous regeneration for the vertical augmentation of the alveolar ridge

    CE Nappe; CE Baltodano

    2013-01-01

    Se considera como aumento óseo vertical, cualquier técnica que apunte a crear una mayor altura del reborde alveolar. A inicios de la década de los 90’s se empezó a utilizar la regeneración ósea guiada (ROG) en mandíbulas atróficas, con el fin de permitir la instalación de implantes óseointegrados. Con el fin de evaluar y exponer parte de la evidencia disponible en la actualidad, con respecto a la ROG para aumento óseo vertical, se realizó la siguiente revisión bibliográfica.Any techniqu...

  19. 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)

  20. 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

  1. 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....

  2. 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

  3. 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).

  4. Hybrid vertical cavity laser

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  5. Composition of vertical gardens

    Sandeva, Vaska; Despot, Katerina

    2013-01-01

    Vertical gardens are fully functional gardens in areas where there is less oxygen and space, ideal for residential and urban cities where there is no vegetation; occupy a special place in interiors furniture. The gardens occupy an important aesthetic problem. Aesthetic task in vertical gardens can be achieved by forming sectors of identification in the urban landscape through the choice of a particular plant spatial composition and composition, to create comfort and representation in commu...

  6. 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...

  7. 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...

  8. 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 ...

  9. 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...

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. Effect of planting density on fruit size, light-interception and photosynthetic activity of vertically trained watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai) plants

    Summary The effect of planting density on fruit size of vertically trained watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai) plants was investigated with regard to light - interception characteristics and photosynthetic production. Watermelon plants, grafted on bottle gourd, were grown in a glasshouse at different planting densities. Two vines per plant were allowed to grow and trained vertically. One hand-pollinated fruit per plant was set around the 15th node on either vine. The solar radiation and photosynthetic rate of individual leaves during fruit development period were determined by an integrated solarimeter film and a portable photosynthesis system, respectively. Fruit size was significantly decreased as the planting density increased, whereas soluble solids content of the fruits was affected little. The solar radiation and the photosynthetic rate of the individual leaves gradually decreased as the leaf position became lower at all planting densities on account of shading; those at lower leaves tended to decrease as the planting density increased. Fruit size was closely related to both the total solar radiation and the photosynthetic production per plant. In conclusion, the difference in fruit size among the planting densities is attributed to the photosynthetic productivity of the whole plant, which is mainly a function of the total solar radiation. This paper appears to be the first trial relating the influence of light interception and photosynthetic rates in high density plantings of vertically trained watermelon plants on fruit size

  19. 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)

  20. 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

  1. 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...

  2. 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

  3. 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).

  4. 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.

  5. 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.

  6. 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.

  7. 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)

  8. 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.

  9. 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...

  10. 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.

  11. 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

  12. Vertical oviposition activity of mosquitoes in the Atlantic Forest of Brazil with emphasis on the sylvan vector, Haemagogus leucocelaenus (Diptera: Culicidae).

    Alencar, Jeronimo; de Mello, Cecilia Ferreira; Gil-Santana, Hélcio R; Guimarães, Anthony Érico; de Almeida, Sergio Antonio Silva; Gleiser, Raquel M

    2016-06-01

    This study aimed to assess the vertical patterns of oviposition and temporal changes in the distribution of mosquito species in an area of the Atlantic Forest in Rio de Janeiro State, Brazil, and in particular, the behavior and oviposition of potential yellow fever virus vectors. Mosquito samples were collected from the Ecological Reserve Guapiaçu (REGUA, Brazil), which includes a somewhat disturbed forest, with a large diversity of plants and animals. In all, 5,458 specimens (ten species from seven genera) were collected. Haemagogus leucocelaenus was the most frequently captured species, representing 73% of the specimens collected. Species richness and diversity were the highest in the samples collected from the ground-level ovitraps and decreased with height. Species composition also differed significantly among heights. The largest species differences were detected between ovitraps set at the ground level and those set at 7 m and 9 m; Hg. leucocelaenus, Limatus durhamii, and Limatus paraensis contributed most to these differences. Sampling month and climatic variables had significant effects on species richness and diversity. Species diversity and richness decreased with height, suggesting that the conditions for mosquito breeding are more favorable closer to the ground. Species composition also showed vertical differences. PMID:27232120

  13. Medium-Term Function of a 3D Printed TCP/HA Structure as a New Osteoconductive Scaffold for Vertical Bone Augmentation: A Simulation by BMP-2 Activation

    Mira Moussa

    2015-04-01

    Full Text Available Introduction: A 3D-printed construct made of orthogonally layered strands of tricalcium phosphate (TCP and hydroxyapatite has recently become available. The material provides excellent osteoconductivity. We simulated a medium-term experiment in a sheep calvarial model by priming the blocks with BMP-2. Vertical bone growth/maturation and material resorption were evaluated. Materials and methods: Titanium hemispherical caps were filled with either bare- or BMP-2 primed constructs and placed onto the calvaria of adult sheep (n = 8. Histomorphometry was performed after 8 and 16 weeks. Results: After 8 weeks, relative to bare constructs, BMP-2 stimulation led to a two-fold increase in bone volume (Bare: 22% ± 2.1%; BMP-2 primed: 50% ± 3% and a 3-fold decrease in substitute volume (Bare: 47% ± 5%; BMP-2 primed: 18% ± 2%. These rates were still observed at 16 weeks. The new bone grew and matured to a haversian-like structure while the substitute material resorbed via cell- and chemical-mediation. Conclusion: By priming the 3D construct with BMP-2, bone metabolism was physiologically accelerated, that is, enhancing vertical bone growth and maturation as well as material bioresorption. The scaffolding function of the block was maintained, leaving time for the bone to grow and mature to a haversian-like structure. In parallel, the material resorbed via cell-mediated and chemical processes. These promising results must be confirmed in clinical tests.

  14. 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

  15. Record Of Both Tectonic Related Vertical Motions and Global Sea Level Rise by Marine Terraces along an Active Arc Volcano. Example of Basse-Terre, Lesser Antilles (French West-Indies).

    Fabre, M.; Moysan, M.; Graindorge, D.; Jean-Frederic, L.; Philippon, M. M.; Marcaillou, B.; Léticée, J. L.

    2015-12-01

    Volcano-tectonic history of the Caribbean plate provides direct insight onto the dynamic of the North American Plate westward subduction. Basse-Terre Island is a volcanic chain that belongs to the Lesser Antilles active volcanic arc with a southward decreasing age of volcanism from 3 Ma to present day.We investigate records of vertical motion along Basse-Terre through a morphostructural analysis of the Pleistocene-Holocene shallow-water carbonate platforms and associated terraces that surround Basse-Terre Island. This study is based on new high-resolution bathymetric and dense seismic data acquired during the GEOTREF oceanographic survey (2015, February). Our bathymetric and topographic Digital Terrain Model together with the "Litto3D" Lidar data (IGN/SHOM) images the island topography and the platform bathymetry to a depth of 200m with horizontal and vertical resolutions of 5m and ~cm respectively. This detailed study highlights the morphostructure of terraces built during the last transgression in order to identify and quantify their vertical motions. We analyze inherited morphology and structures of the forearc that affect the platform to discuss effects of the regional tectonics context. A particular emphasis is put on the influence of the NW-SE arc parallel transtensive Montserrat-Bouillante fault system onto the platform geometry. At last, the distribution of Basse-Terre terraces is compared with terraces distribution around other Lesser Antilles island and the Bahamas stable margin platform. We aim at discriminating the influence of the Pleistocene global sea-level rise from the one of tectonic vertical deformations.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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...

  4. 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

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. 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, ...

  10. Vertical market participation

    Schrader, Alexander; Martin, Stephen

    1998-01-01

    Firms that operate at both levels of vertically related Cournot oligopolies will purchase some input supplies from independent rivals, even though they can produce the good at a lower cost, driving up input price for nonintegrated firms at the final good level. Foreclosure, which avoids this stra...

  11. Global Vertical Reference Frame

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    -, č. 5 (2009), s. 53-63. ISSN 1801-8483 R&D Projects: GA ČR GA205/08/0328 Institutional research plan: CEZ:AV0Z10030501 Keywords : sea surface topography * satellite altimetry * vertical frames Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

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

    LiseDoksæterSivle

    2012-10-01

    Full Text Available 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 5 killer whales (Orcinus orca, 7 long-finned pilot whales (Globicephala melas and 4 sperm whales (Physeter macrocephalus were studied during controlled exposures to naval sonar (LFAS: 1-2 kHz and MFAS: 6-7 kHz during three field seasons (2006-2009. Diving behavior was monitored before, during and after sonar exposure using an archival tag placed on the animal with suction cups. The tag recorded the animal’s vertical movement, and additional data on horizontal movement and vocalizations were used to determine behavioral modes. Killer whales that were conducting deep dives at sonar onset changed abruptly to shallow diving during LFAS, while killer whales conducting deep dives at the onset of MFAS did not alter dive mode. When in shallow diving mode at sonar onset, killer whales did not change their diving behavior. Pilot and sperm whales performed normal deep dives during MFAS exposure. During LFAS exposures, long-finned pilot whales mostly performed fewer deep dives and some sperm whales performed shallower and shorter dives. Acoustic recording data presented previously indicates that deep diving is associated with feeding. Therefore, the observed changes in dive behavior of the three species could potentially reduce the foraging efficiency of the affected animals.

  13. 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 ...

  14. 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.

  15. 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.

  16. 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

  17. 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)

  18. 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.

  19. 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" ...

  20. 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

  1. 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

  2. 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...

  3. 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

  4. 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...

  5. 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.

  6. 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...

  7. 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 ...

  8. 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...

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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 ...

  14. 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 ...

  15. 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.)

  16. 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 %.

  17. 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

  18. 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.

  19. 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.

  20. 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 ...

  1. 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

  2. Vertical organic transistors

    Lüssem, Björn; Günther, Alrun; Fischer, Axel; Kasemann, Daniel; Leo, Karl

    2015-11-01

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted.

  3. 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)

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. Vertical School of Art

    Feijoo, Manuel

    2013-01-01

    Vertical Buildings (skyscrapers) challenge our perception of space, our perception of scale, our idea of movement, they challenge the way we live. Currently urban cities are becoming more and more dense. Lack of space is a big issue and now buildings are being torn down and are replaced by skyscrapers. And these new skyscrapers are being redefined to house a living and working environment. Cubism challenges our perception of depth, our tactile sense, our ideas of proportion. Cubism, as a 20th...

  12. How can the heat transfer correlations for finned-tubes influence the numerical simulation of the dynamic behavior of a heat recovery steam generator?

    This paper presents the results of a theoretical investigation on the influence of different heat transfer correlations for finned-tubes to the dynamic behavior of a heat recovery steam generator (HRSG). The investigation was done for a vertical type natural circulation HRSG with 3 pressure stages under hot start-up and shutdown conditions. For the calculation of the flue gas-side heat transfer coefficient the well known correlations for segmented finned-tubes according to Schmidt, VDI and ESCOATM (traditional and revised) as well as a new correlation, which was developed at the Institute for Energy Systems and Thermodynamics, are used. The simulation results show a good agreement in the overall behavior of the boiler between the different correlations. But there are still some important differences found in the detail analysis of the boiler behavior. - Research highlights: → Numerical simulation is performed to explore the influence of different heat transfer correlations for finned-tubes to the dynamic behavior of a heat recovery steam generator. → Differences in the steam generator behavior are found. → In the worst case the boiler can lead to unfavorable operation conditions, e.g. reverse flow.

  13. How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

    Wensveen, Paulus Jacobus; von Benda-Beckmann, Alexander M.; Ainslie, Michael A; Lam, Frans-Peter A.; Kvadsheim, Petter H.; Tyack, Peter L.; Miller, Patrick J. O.

    2015-01-01

    PJW was supported with studentships of The Netherlands Ministry of Defence (grant number 032.30370/01.02) and the VSB Foundation (grant number VSB.08/228-E) and Ren e Dekeling is acknowledged for making funding possible. The 3S project was supported by the US Office of Naval Research, The Netherlands Ministry of Defence, Royal Norwegian Navy and Norwegian Ministry of Defence, and by World Wildlife Fund Norway. PLT received funding from the MASTS pooling initiative (The Marine Alliance for Scie...

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. Trade elasticity and vertical specialisation

    Ines Buono; Filippo Vergara Caffarelli

    2013-01-01

    This paper shows that vertical specialisation can increase the elasticity of trade to income, hence explaining dramatic events such as the great trade collapse. We argue that a change in the extent of vertical specialisation affects the elasticity of trade to income, while a mere change in global production levels for a given extent of vertical specialisation does not. In the model we show that only large demand shocks induce firms to vary the extent of vertical specialisation. Using panel da...

  1. 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

  2. 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.

  3. Depth-Trim Mapping Control of Underwater Vehicle with Fins

    LI Ye; PANG Yong-jie; HUANG Shu-ling; WAN Lei

    2011-01-01

    Underwater vehicle plays an important role in ocean engineering.Depth control by fin is one of the difficulties for underwater vehicle in motion control.Depth control is indirect due to the freedom coupling between trim and axial motion.It includes the method of dynamic analysis and lift-resistance-coefficient experiment and theory algorithm.By considering the current speed and depth deviation,comprehensive interpretation is used in object-planning instruction.Expected depth is transformed into expected trim.Dynamic output fluctuation can be avoided,which is caused by linear mapping of deviation.It is steady and accurate for the motion of controlled underwater vehicles.The feasibility and efficiency of the control method are testified in the pool and natural area for experiments.

  4. 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...

  5. 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

  6. 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...

  7. Filipinas, fin de siglo: imágenes y realidad

    Elizalde, María Dolores

    1998-08-01

    Full Text Available The objective of this paper is to present an image of the Philippines at the end of the 19th century, different to the picture of underveloped islands, inhabitated by savages unable to selfgovernment, transmited by the historiography and caricatures of that time. With this purpose, they are studied the process of redefinition of the Spanish colonial goverment, the strengthening of a new filipino society, the development of the economy and commerce, and the strong international interests in the islands.

    El presente artículo pretende ofrecer una imagen de las Filipinas de fin de siglo, diferente de la transmitida por la historiografía tradicional y por la viñetas y caricaturas de la época. Frente a los estereotipos de unas islas atrasadas, incapaces del autogobierno, habitadas por salvajes a los que había que civilizar, se impone una realidad definida por el gobierno colonial de España, en pleno proceso de redefinición; por el afianzamiento de una burguesía ilustrada filipina, la pujanza de una clase campesina y obrera, la fuerza de un movimiento de afirmación nacional, y el desarrollo de una economía agroexportadora en pleno crecimiento; y por la presencia de fuertes intereses internacionales que hay que entender insertos en la marea de expansión colonial y reparto de mercados y territorios ultramarinos; intereses internacionales de los que se da cuenta a través de un análisis de comercio, inversiones y presencia diplomática de las grandes potencias en las Filipinas de fin de siglo.

  8. Function of the heterocercal tail in sharks: quantitative wake dynamics during steady horizontal swimming and vertical maneuvering.

    Wilga, C D; Lauder, G V

    2002-08-01

    supporting the classical model of heterocercal tail function for steady horizontal locomotion. Vortex jet angle varies significantly with body angle changes during vertical maneuvering, but sharks show no evidence of active reorientation of jet angle relative to body angle, as was seen in a previous study on the function of sturgeon tail. Vortex jet orientation is significantly more inclined than the relatively horizontal jet generated by sturgeon tail vortex rings, demonstrating substantial differences in function in the heterocercal tails of sharks and sturgeon. We present a summary of forces on a swimming shark integrating data obtained here on the tail with previous data on pectoral fin and body function. Body orientation plays a critical role in the overall force balance and compensates for torques generated by the tail. The pectoral fins do not generate lift during steady horizontal locomotion, but play an important hydrodynamic role during vertical maneuvering. PMID:12124362

  9. GPS, su datum vertical.

    Esteban Dörries

    2016-03-01

    Full Text Available La introducción de la metodología GPS en aplicaciones topográficas y geodésicas pone en notoria evidencia la clásica separación de sistemas de referencia en horizontal y vertical. Con GPS el posicionamiento es tridimensional, pero el concepto de altura difiere del clásico. Si se desea utilizar la información altimétrica debe contemplarse la ondulación del geoide.

  10. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer;

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier, and a...

  11. Factors promoting increased rate of tissue regeneration: the zebrafish fin as a tool for examining tissue engineering design concepts.

    Boominathan, Vijay P; Ferreira, Tracie L

    2012-12-01

    Student interest in topics of tissue engineering is increasing exponentially as the number of universities offering programs in bioengineering are on the rise. Bioengineering encompasses all of the STEM categories: Science, Technology, Engineering, and Math. Inquiry-based learning is one of the most effective techniques for promoting student learning and has been demonstrated to have a high impact on learning outcomes. We have designed program outcomes for our bioengineering program that require tiered activities to develop problem solving skills, peer evaluation techniques, and promote team work. While it is ideal to allow students to ask unique questions and design their own experiments, this can be difficult for instructors to have reagents and supplies available for a variety of activities. Zebrafish can be easily housed, and multiple variables can be tested on a large enough group to provide statistical value, lending them well to inquiry-based learning modules. We have designed a laboratory activity that takes observation of fin regeneration to the next level: analyzing conditions that may impact regeneration. Tissue engineers seek to define the optimum conditions to grow tissue for replacement parts. The field of tissue engineering is likely to benefit from understanding natural mechanisms of regeneration and the factors that influence the rate of regeneration. We have outlined the results of varying temperature on fin regeneration and propose other inquiry modules such as the role of pH in fin regeneration. Furthermore, we have provided useful tools for developing critical thinking and peer review of research ideas, assessment guidelines, and grading rubrics for the activities associated with this exercise. PMID:23244692

  12. A Numerical Study of Natural Convection Heat Transfer in Fin Ribbed Radiator

    Hua-Shu Dou

    2015-01-01

    Full Text Available This paper numerically investigates the thermal flow and heat transfer by natural convection in a cavity fixed with a fin array. The computational domain consists of both solid (copper and fluid (air areas. The finite volume method and the SIMPLE scheme are used to simulate the steady flow in the domain. Based on the numerical results, the energy gradient function K of the energy gradient theory is calculated. It is observed from contours of the temperature and energy gradient function that the position where thermal instability takes place correlates well with the region of large K values, which demonstrates that the energy gradient method reveals the physical mechanism of the flow instability. Furthermore, the effects of the fin height, the fin number, and the fin shape on the heat transfer rate are also investigated. It is found that the thermal performance of the fin array is determined by the combined effect of the fin space and fin height. It is also observed that the effect of fin shape on heat transfer is insignificant.

  13. Influence of Chimney Flow Pattern on Natural Convection Heat Transfer of Open Channel Finned Plates

    Hong, Seung-Hyun; Chung, Bum-Jin [Kyung Hee University, Yongin (Korea, Republic of)

    2015-05-15

    The enhancement of the efficiency and effectiveness of the passive cooling system, have long been the topic of those studies. In this study, we investigated the heat transfer enhancement of finned plates, especially the chimney effect appeared in finned plates. The fin not only enlarges the heat transfer area but also draws fresh fluid from the open side of the channel composed of the base plate and fins, which further enhances the cooling capability of finned plate – a chimney flow pattern. This study aims at investigating the influence of the chimney flow pattern on the natural convection heat transfer of the finned plate. To analyze the phenomenological study, both experimental and numerical analyses were performed. Numerical analysis was performed for the natural convection heat transfer of a finned plate in an open channel. In order to investigate the influence of the chimney flow pattern the heat transfer, several fin height were simulated and compared. The temperature profiles varied drastically depending on the values of the Prandtl number. As the Prandtl number increases, the thermal boundary layer reduces.

  14. Influence of Chimney Flow Pattern on Natural Convection Heat Transfer of Open Channel Finned Plates

    The enhancement of the efficiency and effectiveness of the passive cooling system, have long been the topic of those studies. In this study, we investigated the heat transfer enhancement of finned plates, especially the chimney effect appeared in finned plates. The fin not only enlarges the heat transfer area but also draws fresh fluid from the open side of the channel composed of the base plate and fins, which further enhances the cooling capability of finned plate – a chimney flow pattern. This study aims at investigating the influence of the chimney flow pattern on the natural convection heat transfer of the finned plate. To analyze the phenomenological study, both experimental and numerical analyses were performed. Numerical analysis was performed for the natural convection heat transfer of a finned plate in an open channel. In order to investigate the influence of the chimney flow pattern the heat transfer, several fin height were simulated and compared. The temperature profiles varied drastically depending on the values of the Prandtl number. As the Prandtl number increases, the thermal boundary layer reduces

  15. The impact of line edge roughness on the stability of a FinFET SRAM

    3D mixed-mode device-circuit simulation is presented to investigate the impact of line edge roughness (LER) on the stability of a FinFET SRAM. In this work, LER sequence is statistically generated by a Fourier analysis of the power spectrum of Gaussian autocorrelation function. The sensitivity of 20 nm FinFET SRAM of Read and Write static noise margins (SNM) to fin LER is evaluated. The results show that FinFET SRAM is more tolerant of disturbance in write operation than in read disturbance. The dependence of Read SNM on fin LER's root mean square (RMS) amplitude, fin thickness and supply voltage is also analyzed. Furthermore, methods to reduce the LER effect on the FinFET SRAM's read stability are introduced. Optimization of the cell ratio by a multiple-fin design, control of the access transistor's gate bias voltage and replacement of a 6T cell with an 8T cell are possible solutions to continue the scaling trend of SRAM in the nanoscale CMOS technology

  16. Mechanical Properties of Cold Gas Dynamic-Sprayed Near-Net-Shaped Fin Arrays

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

    2015-02-01

    This work focuses on the study of the adhesion and thermal performance of near-net-shaped pyramidal fin arrays manufactured by cold spray on aluminum alloy substrate coated with various bond coats: a cold-sprayed bond coat as well as nitrogen- and air-propelled arc-sprayed bond coats. Furthermore, the effects of the fin density, fin height, and substrate surface roughness on the adhesion strength of the fins deposited on Al6061 substrates were characterized. It was found that the fin density, the fin height, and the substrate roughness have little impact on the adhesion strength of this system. The adhesion strength was found to be inversely proportional to the surface hardness when investigating these parameters for the different thermal-spray bond coatings, with all the fin systems having a much greater strength than the theoretical application stresses. Finally, it was found that the increase in the fin's base layer's roughness increases the overall heat transfer, with the bond coat material having a negligible effect on the thermal resistance for this type of heat-exchanger configuration.

  17. Fin-efficiency calculation for condensation in the presence of noncondensable gases

    Panchal, C. B.

    Plate-fin heat exchangers are being considered for many condenser applications. They are commonly used for the gas-separation process because they can provide a high thermal performance to obtain a low mean-temperature difference, essential for the gas-separation process. Plate-fin heat exchangers are also considered for the heat-pump system using nonazeotropic refrigerant mixtures. The brazed plate-fin condenser was considered to be a leading candidate for the Ocean Thermal Energy Conversion (OTEC) system, where high-performance heat exchangers are essential for maintaining a low mean-temperature difference. Calculation of the fin efficiency is difficult for condensation in the presence of noncondensable gases due to the spatial variation of the interfacial temperature. An analysis was carried out to develop a simplified method to calculate the fin efficiency for condensation of a vapor in the presence of noncondensable gases. The analysis includes the variation in the interfacial temperature along the fin surface. Appropriate assumptions are made to simplify the coupled heat-conduction equation in the fin and the heat/mass fluxes at the interface. The resulting expression for the fin efficiency includes mass-flux parameters, and it is similar to the common expression used for single-phase flow.

  18. Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus

    Mazzariol, Sandro; Centelleghe, Cinzia; Beffagna, Giorgia; Povinelli, Michele; Terracciano, Giuliana; Cocumelli, Cristiano; Pintore, Antonio; Denurra, Daniele; Casalone, Cristina; Pautasso, Alessandra; Di Francesco, Cristina Esmeralda; Di Guardo, Giovanni

    2016-01-01

    During 2011–2013, dolphin morbillivirus was molecularly identified in 4 stranded fin whales from the Mediterranean Sea. Nucleoprotein, phosphoprotein, and hemagglutinin gene sequences of the identified strain were highly homologous with those of a morbillivirus that caused a 2006–2007 epidemic in the Mediterranean. Dolphin morbillivirus represents a serious threat for fin whales.

  19. Performance of residential air-conditioning systems with flow maldistribution in fin-and-tube evaporators

    Kærn, Martin Ryhl; Brix, Wiebke; Elmegaard, Brian;

    2011-01-01

    Refrigerant and airflow maldistribution in fin-and-tube evaporators for residential air-conditioning was investigated with numerical modeling. Fin-and-tube heat exchangers usually have a pre-defined circuitry. However, the objective in this study was to perform a generic investigation of each...

  20. Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus.

    Mazzariol, Sandro; Centelleghe, Cinzia; Beffagna, Giorgia; Povinelli, Michele; Terracciano, Giuliana; Cocumelli, Cristiano; Pintore, Antonio; Denurra, Daniele; Casalone, Cristina; Pautasso, Alessandra; Di Francesco, Cristina Esmeralda; Di Guardo, Giovanni

    2016-02-01

    During 2011-2013, dolphin morbillivirus was molecularly identified in 4 stranded fin whales from the Mediterranean Sea. Nucleoprotein, phosphoprotein, and hemagglutinin gene sequences of the identified strain were highly homologous with those of a morbillivirus that caused a 2006-2007 epidemic in the Mediterranean. Dolphin morbillivirus represents a serious threat for fin whales. PMID:26812485

  1. Numerical analysis of air-foil shaped fin performance in printed circuit heat exchanger in a supercritical carbon dioxide power cycle

    Kim, Tae Ho [Department of Mechanical Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kwon, Jin Gyu [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Yoon, Sung Ho [Korea Institute of Nuclear Nonproliferation and Control, Daejeon 305-348 (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of); Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)

    2015-07-15

    Highlights: • Staggered arrangement affects the pressure drop but does not significantly affect to the heat transfer. • The total pressure drop is reduced, but the amount of acceleration pressure drop increases while that of frictional pressure drop decreases as the horizontal number increases. • For the vertical number, the total pressure drop decreases more largely than the horizontal number. • The objective function shows that the fully staggered arrangement shows best performance. - Abstract: One of the key issues of the PCHE technology in the supercritical CO{sub 2} Brayton cycle is to achieve an efficient and compact designs to be able to enhance heat transfer and reduce pressure drop. The issue is challenging due to the complex configuration of micro-channels in the PCHE. In this study, an innovative micro-channel equipped with an array of airfoil fins is analyzed to evaluate its performance. In so doing, sensitivity analysis with various design parameters is performed to configure the optimal arrangement of airfoil fins by using CFD analysis for Supercritical Carbon dioxide Integral Experimental Loop (SCIEL) in Korean Atomic Energy Research Institute (KAERI). Dominant geometric parameters of the fin arrangement that affects to the thermal and hydraulic performances are the horizontal, vertical and staggered pitches. ANSYS ICEM CFD and ANSYS CFX are used for the grid generation and the computational calculation. CO{sub 2} properties are used by using REFPROF software database. The inlet temperature of the hot side is 618 K and that of the cold side is 585 K. The reference mass flow rate is set as 1.2 g/s for the vertical number of 2.0, which is the Reynolds number of about 30,000. The mass flow rate changes from 0.4 to 4.8 g/s in order to investigate the Reynolds number effect. The k-ε model is selected as the turbulence model. In conclusions, the results show that the optimal arrangement of airfoil fins can be examined in terms of an objective

  2. Numerical analysis of air-foil shaped fin performance in printed circuit heat exchanger in a supercritical carbon dioxide power cycle

    Highlights: • Staggered arrangement affects the pressure drop but does not significantly affect to the heat transfer. • The total pressure drop is reduced, but the amount of acceleration pressure drop increases while that of frictional pressure drop decreases as the horizontal number increases. • For the vertical number, the total pressure drop decreases more largely than the horizontal number. • The objective function shows that the fully staggered arrangement shows best performance. - Abstract: One of the key issues of the PCHE technology in the supercritical CO2 Brayton cycle is to achieve an efficient and compact designs to be able to enhance heat transfer and reduce pressure drop. The issue is challenging due to the complex configuration of micro-channels in the PCHE. In this study, an innovative micro-channel equipped with an array of airfoil fins is analyzed to evaluate its performance. In so doing, sensitivity analysis with various design parameters is performed to configure the optimal arrangement of airfoil fins by using CFD analysis for Supercritical Carbon dioxide Integral Experimental Loop (SCIEL) in Korean Atomic Energy Research Institute (KAERI). Dominant geometric parameters of the fin arrangement that affects to the thermal and hydraulic performances are the horizontal, vertical and staggered pitches. ANSYS ICEM CFD and ANSYS CFX are used for the grid generation and the computational calculation. CO2 properties are used by using REFPROF software database. The inlet temperature of the hot side is 618 K and that of the cold side is 585 K. The reference mass flow rate is set as 1.2 g/s for the vertical number of 2.0, which is the Reynolds number of about 30,000. The mass flow rate changes from 0.4 to 4.8 g/s in order to investigate the Reynolds number effect. The k-ε model is selected as the turbulence model. In conclusions, the results show that the optimal arrangement of airfoil fins can be examined in terms of an objective function and it

  3. Vertical organic transistors

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted. (topical review)

  4. Convective Heat Transfer Augmentation by Flexible fins in Laminar Channel Pulsating flow

    Joshi, Rakshitha U; Bhardwaj, Rajneesh

    2015-01-01

    Fluid-structure interaction (FSI) of thin flexible fins coupled with convective heat transfer has applications in energy harvesting and in understanding functioning of several biological systems. We numerically investigate FSI of the thin flexible fins involving large-scale flow-induced deformation as a potential heat transfer enhancement technique. An in-house, strongly-coupled fluid-structure interaction (FSI) solver is employed in which flow and structure solvers are based on sharp-interface immersed boundary and finite element method, respectively. We consider twin flexible fins in a heated channel with laminar pulsating cross flow. The vortex ring past the fin sweep higher sources of vorticity generated on the channel walls out into the downstream - promoting the mixing of the fluid. The moving fin assists in convective mixing, augmenting convection in bulk and at the walls; and thereby reducing thermal boundary layer thickness and improving heat transfer at the channel walls. The thermal augmentation is...

  5. Laminar fluid flow and heat transfer in a fin-tube heat exchanger with vortex generators

    Yanagihara, J.I.; Rodriques, R. Jr. [Polytechnic School of Univ. of Sao Paolo, Sao Paolo (Brazil). Dept. of Mechanical Engineering

    1996-12-31

    Development of heat transfer enhancement techniques for fin-tube heat exchangers has great importance in industry. In recent years, heat transfer augmentation by vortex generators has been considered for use in plate fin-tube heat exchangers. The present work describes a numerical investigation about the influence of delta winglet pairs of vortex generators on the flow structure and heat transfer of a plate fin-tube channel. The Navier-Stokes and Energy equations are solved by the finite volume method using a boundary-fitted coordinate system. The influence of vortex generators parameters such as position, angle of attack and aspect ratio were investigated. Local and global influences of vortex generators in heat transfer and flow losses were analyzed by comparison with a model using smooth fin. The results indicate great advantages of this type of geometry for application in plate fin-tube heat exchangers, in terms of large heat transfer enhancement and small pressure loss penalty. (author)

  6. NUMERICAL STUDY ON FLOW DISTRIBUTION IN PLATE-FIN HEAT EXCHANGERS

    张哲; 厉彦忠

    2003-01-01

    Objective To investigate the flow distribution in plate-fin heat exchangers and optimize the design of header configuration for plate-fin heat exchangers. Methods A mathematical model of header was proposed. The effects of the header configuration on the flow distribution in plate-fin heat exchangers were investigated by CFD. The second header configuration with a two-stage-distributing structure was brought forward to improve the performance of flow distribution. Results It is found that the flow maldistribution is very serious in the direction of header length for the conventional header used in industry. The numerical predictions indicate that the improved header configurations can effectively improve the performance of flow distribution in plate-fin heat exchangers. Conclusion The numerical simulation confirms that CFD should be a suitable tool for predicting the flow distribution. The method has a wide variety of applications in the design of plate-fin heat exchangers.

  7. Bio-inspired flexible joints with passive feathering for robotic fish pectoral fins.

    Behbahani, Sanaz Bazaz; Tan, Xiaobo

    2016-06-01

    In this paper a novel flexible joint is proposed for robotic fish pectoral fins, which enables a swimming behavior emulating the fin motions of many aquatic animals. In particular, the pectoral fin operates primarily in the rowing mode, while undergoing passive feathering during the recovery stroke to reduce hydrodynamic drag on the fin. The latter enables effective locomotion even with symmetric base actuation during power and recovery strokes. A dynamic model is developed to facilitate the understanding and design of the joint, where blade element theory is used to calculate the hydrodynamic forces on the pectoral fins, and the joint is modeled as a paired torsion spring and damper. Experimental results on a robotic fish prototype are presented to illustrate the effectiveness of the joint mechanism, validate the proposed model, and indicate the utility of the proposed model for the optimal design of joint depth and stiffness in achieving the trade-off between swimming speed and mechanical efficiency. PMID:27144946

  8. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  9. Histology, histochemistry and stereology of the adipose fin of Prochilodus lineatus.

    Alves, Rebeca Mamede da Silva; Pereira, Bruno Fiorelini; Pitol, Dimítrius Leonardo; Senhorini, José Algusto; Rocha, Rita de Cássia Gimenes de Alcântara; Caetano, Flavio Henrique

    2012-05-01

    The adipose fin is small, nonpared, and usually located medially between the dorsal and caudal fin. Its taxonomic occurrence is very restrict; thus, it represents an important trace for taxon distinction. As it does not play a known vital physiological roll and it is easily removed, it is commonly used in marking and recapture studies. The present study characterizes the adipose fin of Prochilodus lineatus, as it is poorly explored by the literature. The adipose fin consists basically of a loose connective core, covered by a stratified epithelium supported by collagen fibers. At the epithelium, pigmented cells and alarm substance cells are found. Despite the name, adipocytes or lipid droplets are not observed on the structure of the fin. PMID:22038664

  10. The use of pelvic fins for benthic locomotion during foraging behavior in Potamotrygon motoro (Chondrichthyes: Potamotrygonidae

    Akemi Shibuya

    2015-06-01

    Full Text Available Synchronized bipedal movements of the pelvic fins provide propulsion (punting during displacement on the substrate in batoids with benthic locomotion. In skates (Rajidae this mechanism is mainly generated by the crural cartilages. Although lacking these anatomical structures, some stingray species show modifications of their pelvic fins to aid in benthic locomotion. This study describes the use of the pelvic fins for locomotory performance and body re-orientation in the freshwater stingray Potamotrygon motoro (Müller & Henle, 1841 during foraging. Pelvic fin movements of juvenile individuals of P. motoro were recorded in ventral view by a high-speed camera at 250-500 fields/s-1. Potamotrygon motoro presented synchronous, alternating and unilateral movements of the pelvic fins, similar to those reported in skates. Synchronous movements were employed during straightforward motion for pushing the body off the substrate as well as for strike feeding, whereas unilateral movements were used to maneuver the body to the right or left during both locomotion and prey capture. Alternating movements of the pelvic fins are similar to bipedal movements in terrestrial and semi-aquatic tetrapods. The pelvic fins showed coordinated movements during feeding even when stationary, indicating that they have an important function in maintaining body posture (station holding during prey capture and manipulation. The use of pelvic fins during prey stalking may be advantageous because it results in less substrate disturbance when compared to movements generated by pectoral fin undulation. The range of pelvic fin movements indicates more complex control and coordination of the pelvic radial muscles.

  11. Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

    Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-05-01

    Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

  12. FEM simulation for cold press forging forming of the round-fin heat sink

    Wang, Kesheng; Han, Yu; Zhang, Haiyan; Zhang, Lihan

    2013-05-01

    In this paper, the finite element method is used to investigate the forming process of cold press forging for the round-fin heat sink in the automotive lighting. A series of simulations on the round-fin heat sink forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied, and the tooling structure with counterpressure on the heat sink formation was also investigated. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also When both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin. Meanwhile, The tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, and the simulation results are in good agreement with the experimental data.

  13. A numerical method for PCM-based pin fin heat sinks optimization

    Highlights: • Optimization of PCM-based heat sink by using the Taguchi method. • Derivation of optimal PCM percentage to reach the maximum critical time. • Optimization is performed for four different critical temperatures. • Effective design factors are fins’ height and fins’ number. • The optimum configuration depends on geometric properties and the critical temperature. - Abstract: This paper presents a numerical investigation on geometric optimization of PCM-based pin fin heat sinks. Paraffin RT44HC is used as PCM while the fins and heat sink base is made of aluminum. The fins act as thermal conductivity enhancers (TCEs). The main goal of the study is to obtain the configurations that maximize the heat sink operational time. An approach witch couples Taguchi method with numerical simulations is utilized for this purpose. Number of fins, fins height, fins thickness and the base thickness are parameters which are studied for optimization. In this study natural convection and PCM volume variation during melting process are considered in the simulations. Optimization is performed for different critical temperatures of 50 °C, 60 °C, 70 °C and 80 °C. Results show that a complex relation exists between PCM and TCE volume percentages. The optimal case strongly depends on the fins’ number, fins’ height and thickness and also the critical temperature. The optimum PCM percentages are found to be 60.61% (corresponds to 100 pin fin heat sink with 4 mm thick fins) for critical temperature of 50 °C and 82.65% (corresponds to 100 pin fin heat sink with 2 mm thick fins) for other critical temperatures

  14. Vertical vibration analysis for elevator compensating sheave

    Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified

  15. Vertical Protocol Composition

    Groß, Thomas; Mödersheim, Sebastian Alexander

    2011-01-01

    composition, and it is truly commonplace in today’s communication with the diversity of VPNs and secure browser sessions. In fact, it is normal that we have several layers of secure channels: For instance, on top of a VPN-connection, a browser may establish another secure channel (possibly with a different...... end point). Even using the same protocol several times in such a stack of channels is not unusual: An application may very well establish another TLS channel over an established one. We call this selfcomposition. In fact, there is nothing that tells us that all these compositions are sound, i.e., that...... the combination cannot introduce attacks that the individual protocols in isolation do not have. In this work, we prove a composability result in the symbolic model that allows for arbitrary vertical composition (including self-composition). It holds for protocols from any suite of channel and...

  16. Calling behavior of blue and fin whales off California

    Oleson, Erin Marie

    Passive acoustic monitoring is an effective means for evaluating cetacean presence in remote regions and over long time periods, and may become an important component of cetacean abundance surveys. To use passive acoustic recordings for abundance estimation, an understanding of the behavioral ecology of cetacean calling is crucial. In this dissertation, I develop a better understanding of how blue (Balaenoptera musculus) and fin (B. physalus ) whales use sound with the goal of evaluating passive acoustic techniques for studying their populations. Both blue and fin whales produce several different call types, though the behavioral and environmental context of these calls have not been widely investigated. To better understand how calling is used by these whales off California I have employed both new technologies and traditional techniques, including acoustic recording tags, continuous long-term autonomous acoustic recordings, and simultaneous shipboard acoustic and visual surveys. The outcome of these investigations has led to several conclusions. The production of blue whale calls varies with sex, behavior, season, location, and time of day. Each blue whale call type has a distinct behavioral context, including a male-only bias in the production of song, a call type thought to function in reproduction, and the production of some calls by both sexes. Long-term acoustic records, when interpreted using all call types, provide a more accurate measure of the local seasonal presence of whales, and how they use the region annually, seasonally and daily. The relative occurrence of different call types may indicate prime foraging habitat and the presence of different segments of the population. The proportion of animals heard calling changes seasonally and geographically relative to the number seen, indicating the calibration of acoustic and visual surveys is complex and requires further study on the motivations behind call production and the behavior of calling whales

  17. Direct Observation of Ultralow Vertical Emittance using a Vertical Undulator

    Wootton, Kent

    2015-09-17

    In recent work, the first quantitative measurements of electron beam vertical emittance using a vertical undulator were presented, with particular emphasis given to ultralow vertical emittances [K. P. Wootton, et al., Phys. Rev. ST Accel. Beams, 17, 112802 (2014)]. Using this apparatus, a geometric vertical emittance of 0.9 ± 0.3 pm rad has been observed. A critical analysis is given of measurement approaches that were attempted, with particular emphasis on systematic and statistical uncertainties. The method used is explained, compared to other techniques and the applicability of these results to other scenarios discussed.

  18. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Heidar Sadeghzadeh; Mehdi Aliehyaei; Marc A. Rosen

    2015-01-01

    Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The...

  19. Propulsion efficiency of bodies appended with multiple flapping fins: When more is less

    Bandyopadhyay, Promode R.; Leinhos, Henry A.

    2013-04-01

    Underwater animals propel themselves by flapping their pectoral and caudal fins in a narrow range of frequencies, given by Strouhal number St, to produce transitional vortex jets (St is generally expressed non-dimensionally as the product of flapping frequency and stroke (arc) length divided by forward speed). The organized nature of the selection of St and of the vortex jet is thought to maximize hydrodynamic efficiency, although the exact mechanism is not known. Our recent Stuart-Landau equation models, which have self-regulation properties, indicate that the fin and its jet vortices couple. Temporal maps of forces in single isolated fins show a bimodal behavior in certain ranges of the transitional Reynolds number; this behavior bears resemblance to neural bifurcation properties that owe their origin to the self-regulation mechanism. In view of our theoretical and biorobotic evidence of self-regulation in single flapping fins, we explore if this property is altered in a fin-appended body, the goal being to understand how the narrow selection of St, self-regulation, and maximization of hydrodynamic efficiency are related. Swimming vehicles of 1-m scale have been built where a rigid cylindrical body is appended with six flapping fins, three at each end. The fins are rigid, have a rounded leading edge and a laminar section (NACA 0012), and are hinged at one end. The planform is an abstracted version of the penguin wing; it has low aspect ratio and a chord Reynolds number that varies in the transitional range from 10 000 to 60 000. The fin geometry, Reynolds number range, and the nonflexible nature of the main body are in common with those in penguins, and the length and displacement volume are similar to those of sharks. The maximum hydrodynamic efficiency of the fin-appended body (0.40) is lower than that of the single fin (0.57), but is close to that of a fish using several fins. The propulsion density (kW/m3 of displacement volume) of the fin-appended cylinder

  20. A novel trapezoid fin pattern applicable for air-cooled heat sink

    Chen, Chien-Hung; Wang, Chi-Chuan

    2015-11-01

    The present study proposed a novel step or trapezoid surface design applicable to air-cooled heat sink under cross flow condition. A total of five heat sinks were made and tested, and the corresponding fin patterns are (a) plate fin; (b) step fin (step 1/3, 3 steps); (c) 2-step fin (step 1/2, 2 steps); (d) trapezoid fin (trap 1/3, cutting 1/3 length from the rear end) and (e) trapezoid fin (trap 1/2, cutting 1/2 length from the rear end). The design is based on the heat transfer augmentation via (1) longer perimeter of entrance region and (2) larger effective temperature difference at the rear part of the heat sink. From the test results, it is found that either step or trapezoid design can provide a higher heat transfer conductance and a lower pressure drop at a specified frontal velocity. The effective conductance of trap 1/3 design exceeds that of plate surface by approximately 38 % at a frontal velocity of 5 m s-1 while retains a lower pressure drop of 20 % with its surface area being reduced by 20.6 %. For comparisons exploiting the overall thermal resistance versus pumping power, the resultant thermal resistance of the proposed trapezoid design 1/3, still reveals a 10 % lower thermal resistance than the plate fin surface at a specified pumping power.

  1. Fish's Muscles Distortion and Pectoral Fins Propulsion of Lift-Based Mode

    Yang, S. B.; Han, X. Y.; Qiu, J.

    As a sort of MPF(median and/or paired fin propulsion), pectoral fins propulsion makes fish easier to maneuver than other propulsion, according to the well-established classification scheme proposed by Webb in 1984. Pectoral fins propulsion is classified into oscillatory propulsion, undulatory propulsion and compound propulsion. Pectoral fins oscillatory propulsion, is further ascribable to two modes: drag-based mode and lift-based mode. And fish exhibits strong cruise ability by using lift-based mode. Therefore to robot fish design using pectoral fins lift-based mode will bring a new revolution to resources exploration in blue sea. On the basis of the wave plate theory, a kinematic model of fish’s pectoral fins lift-based mode is established associated with the behaviors of cownose ray (Rhinoptera bonasus) in the present work. In view of the power of fish’s locomotion from muscle distortion, it would be helpful benefit to reveal the mechanism of fish’s locomotion variation dependent on muscles distortion. So this study puts forward the pattern of muscles distortion of pectoral fins according to the character of skeletons and muscles of cownose ray in morphology and simulates the kinematics of lift-based mode using nonlinear analysis software. In the symmetrical fluid field, the model is simulated left-right symmetrically or asymmetrically. The results qualitatively show how muscles distortion determines the performance of fish locomotion. Finally the efficient muscles distortion associated with the preliminary dynamics is induced.

  2. Design, Implementation and Control of a Fish Robot with Undulating Fins

    Mohsen Siahmansouri

    2011-11-01

    Full Text Available Biomimetic robots can potentially perform better than conventional robots in underwater vehicle designing. This paper describes the design of the propulsion system and depth control of a robotic fish. In this study, inspired by knife fish, we have designed and implemented an undulating fin to produce propulsive force. This undulating fin is a segmental anal fin that produces sinusoidal wave to propel the robot. The relationship between the individual fin segment and phase angles with the overall fin trajectory has also been discussed. This propulsive force can be adjusted and directed for fish robot manoeuvre by a mechanical system with two servomotors. These servomotors regulate the direction and depth of swimming. A wireless remote control system is designed to adjust the servomotors which enables us to control revolution, speed and phase differences of neighbor servomotors of fins. Finally, Field trials are conducted in an outdoor pool to demonstrate the relationship between robotic fish speed and fin parameters like phase difference, the number of phase and undulatory amplitude.

  3. Dynamic stiffness testing-based flutter analysis of a fin with an actuator

    Zhang Renjia

    2015-10-01

    Full Text Available Engineering-oriented modeling and synthesized modeling of the fin-actuator system of a missile fin are introduced, including mathematical modeling of the fin, motor and multi-stage gear reducer. The fin-actuator model is verified using dynamic stiffness testing. Good agreement is achieved between the test and theoretical results. The parameter-variable analysis indicates that the inertia of the motor rotor, reduction ratio of the reducer, connection stiffness and damping between the actuator and fin shaft have significant impacts on the dynamic stiffness characteristics. In flutter analysis, test data are directly used in the frequency domain method and indirectly used in the time domain method through the updated fin-actuator model. The two methods play different roles in engineering applications but are of equal importance. The results indicate that dynamic stiffness and constant stiffness treatments may lead to completely different flutter characteristics. Attention should be paid to the design of the fin-actuator system of a missile.

  4. The Oldest Actinopterygian Highlights the Cryptic Early History of the Hyperdiverse Ray-Finned Fishes.

    Lu, Jing; Giles, Sam; Friedman, Matt; den Blaauwen, Jan L; Zhu, Min

    2016-06-20

    Osteichthyans comprise two divisions, each containing over 32,000 living species [1]: Sarcopterygii (lobe-finned fishes and tetrapods) and Actinopterygii (ray-finned fishes). Recent discoveries from China highlight the morphological disparity of early sarcopterygians and extend their origin into the late Silurian [2-4]. By contrast, the oldest unambiguous actinopterygians are roughly 30 million years younger, leaving a long temporal gap populated by fragments and rare body fossils of controversial phylogenetic placement [5-10]. Here we reinvestigate the enigmatic osteichthyan Meemannia from the Early Devonian (∼415 million years ago) of China, previously identified as an exceptionally primitive lobe-finned fish [3, 7, 11, 12]. Meemannia combines "cosmine"-like tissues taken as evidence of sarcopterygian affinity with actinopterygian-like skull roof and braincase geometry, including endoskeletal enclosure of the spiracle and a lateral cranial canal. We report comparable histological structures in undoubted ray-finned fishes and conclude that they are general osteichthyan features. Phylogenetic analysis places Meemannia as an early-diverging ray-finned fish, resolving it as the sister lineage of Cheirolepis [13] plus all younger actinopterygians. This brings the first appearance of ray-fins more in line with that of lobe-fins and fills a conspicuous faunal gap in the otherwise diverse late Silurian-earliest Devonian vertebrate faunas of the South China Block [4]. PMID:27212403

  5. Analytical and numerical solution along with PC spreadsheets modeling for a composite fin

    Mokheimer, E. M. A.; Antar, M. A.; Farooqi, J.; Zubair, S. M.

    Heat transfer through composite fins is investigated by both analytical and numerical methods. In this regard, governing differential equations of the two dimensional fin and one dimensional cladding are studied to examine the effect of Biot number and ratio of thermal conductivities of the fin material to the cladding, on the dimensionless temperature profiles. The results show that one dimensional analysis, traditionally used in fin analysis, is not applicable for composite fins, particularly when the conductivity ratio of the composite fin materials is low. In addition, the use of spreadsheet programs in solving the fin problem is investigated in somewhat more detail with regard to the solution as well as presentation of the graphical results. Zusammenfassung Die Wärmeabfuhr durch Kompositrippen wird sowohl analytisch, als auch numerisch untersucht, wobei die Rippe selbst als zweidimensionales, die Umhüllung als eindimensionales Gebiet den Differentialgleichungen der Wärmeleitung zugrunde gelegt werden. Dem Einfluß der Biot-Zahl und des Verhältnisses der Wärmeleitfähigkeiten von Rippen- und Umhüllungsmaterial auf die dimensionslosen Temperaturprofile gilt besonderes Interesse. Die Ergebnisse zeigen, daß die übliche eindimensionale Rippentheorie bei Kompositrippen nicht hinreicht, besonders wenn das Verhältnis der Leitfähigkeiten beider Materialien niedrig ist. Die Methode der Tabellenberechnung wird besonders eingehend behandelt und zwar sowohl mit Blick auf die Lösung, wie auch die graphische Darstellung der Ergebnisse.

  6. Experimental Analysis Of Heat Transfer From Square Perforated Fins In Staggered Arrangement

    Siddiqui. M. Abdullah

    2015-08-01

    Full Text Available This project gives the experimental analysis of heat transfer over a flat surface equipped with Square perforated pin fins in staggered arrangement in a rectangular channel. The Fin dimensions are 100mm in height & 25mm in width. The range of Reynolds number is fixed & about 13,500– 42,000, the clearance ratio (C/H 0, 0.33 and 1, the inter-fin spacing ratio (Sy /D 1.208, 1.524, 1.944 and 3.417. Sy i.e. stream wise distance is varies and Sx i.e. span wise distance is constant. The friction factor, enhancement efficiency and heat transfer correlate in equations with each other. Here we are comparing Square pin fins with cylindrical pin fins. Staggered arrangement and perforation will enhance the heat transfer rate. Clearance ratio and inter-fin spacing ratio affect on Enhancement efficiency. Both lower clearance ratio and lower inter-fin spacing ratio and comparatively lower Reynolds number give higher thermal performance. Friction factor & Nusselt number are Key parameter which relates with efficiency enhancement and heat transfer rate.

  7. Thermal management of electronics using phase change material based pin fin heat sinks

    This paper reports the results of an experimental study carried out to explore the thermal characteristics of phase change material based heat sinks for electronic equipment cooling. The phase change material (PCM) used in this study is n – eicosane. All heat sinks used in the present study are made of aluminium with dimensions of 80 × 62 mm2 base with a height of 25 mm. Pin fins acts as the thermal conductivity enhancer (TCE) to improve the distribution of heat more uniformly as the thermal conductivity of the PCM is very low. A total of three different pin fin heat sink geometries with 33, 72 and 120 pin fins filled with phase change materials giving rise to 4%, 9% and 15% volume fractions of the TCE respectively were experimentally investigated. Baseline comparisons are done with a heat sink filled with PCM, without any fin. Studies are conducted for heat sinks on which a uniform heat load is applied at the bottom for the finned and unfinned cases. The effect of pin fins of different volume fractions with power levels ranging from 4 to 8 W corresponding to a heat flux range of 1. 59 to 3.17 kW/m2, was explored in this paper. The volume fraction of the PCM (PCM volume / (Total volume – fin volume)) is also varied as 0. 3, 0.6 and 1 to determine the effect of PCM volume on the overall performance of the electronic equipment.

  8. Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification

    Zheng Hui-Fan

    2013-01-01

    Full Text Available A theoretical analysis and experimental verification on the characteristics of a micro-fin evaporator using R290 and R717 as refrigerants were carried out. The heat capacity and heat transfer coefficient of the micro-fin evaporator were investigated under different water mass flow rate, different refrigerant mass flow rate, and different inner tube diameter of micro-fin evaporator. The simulation results of the heat transfer coefficient are fairly in good agreement with the experimental data. The results show that heat capacity and the heat transfer coefficient of the micro-fin evaporator increase with increasing logarithmic mean temperature difference, the water mass flow rate and the refrigerant mass flow rate. Heat capacity of the micro-fin evaporator for diameter 9.52 mm is higher than that of diameter 7.00 mm with using R290 as refrigerant. Heat capacity of the micro-fin evaporator with using R717 as refrigerant is higher than that of R290 as refrigerant. The results of this study can provide useful guidelines for optimal design and operation of micro-fin evaporator in its present or future applications.

  9. Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

    Md. Mahbubar Rahman; Yasuyuki Toda; Hiroshi Miki

    2011-01-01

    The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin's principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

  10. Embedded Fin-Like Metal/CNT Hybrid Structures for Flexible and Transparent Conductors.

    Jiang, Di; Wang, Nan; Edwards, Michael; Mu, Wei; Nylander, Andreas; Fu, Yifeng; Jeppson, Kjell; Liu, Johan

    2016-03-01

    In this paper, an embedded fin-like metal-coated carbon nanotube (Fin-M/CNT) structure is demonstrated for flexible and transparent conductor wire applications. Embedded in a polydimethylsiloxane polymeric substrate, Fin-M/CNT wires with a minimum width of 5 μm and a minimum pitch of 10 μm have been achieved. Direct current resistances of single Fin-M/CNT wires, where the supporting CNT structures have been covered by Ti/Al/Au metal coatings of different thicknesses, have been measured. The high aspect ratio of the fin-like structures not only improves the adhesion between the wires and the polymeric substrate, but also yields a low resistance at a small surface footprint. In addition, transparent Fin-M/CNT grid lines with hexagonal patterns, with a sheet resistance of as low as 45 Ω sq(-1) , have been achieved at an optical transmittance of 88%. The robustness of the Fin-M/CNT structures has been demonstrated in bending tests up to 500 cycles and no significant changes in wire resistances are observed. PMID:26766128

  11. Effect of vapour velocity on condensate retention on horizontal pin-fin tubes

    Highlights: • Effect of vapour velocity on condensate retention is reported on pin-fin tubes. • Condensate was simulated using R-141b, water and ethylene glycol. • Vapour was simulated using air. • Retention angle when less than 90° at low velocity, increased with velocity increase. • Velocity marginally effected retention angle when greater than 90° at low velocity. - Abstract: New experimental data for condensate retention angle as a function of vapour velocity (0–19 m/s) are reported on six horizontal pin-fin tubes and an equivalent integral-fin tube (i.e. with same longitudinal fin spacing, tooth thickness, tooth height, inner and outer diameter as that of pin-fin tubes) using water, ethylene glycol and R-141b. Only geometric parameter varied was the circumferential pin spacing. For all tubes tested, an increase in vapour velocity causes an increase in condensate retention angle for the cases when retention angle was less than 90° at low approaching zero vapour velocity. For the cases when the retention angle was greater than 90° at low approaching zero vapour velocity, vapour velocity shows negligible effect on retention angle for all pin-fin tubes, while for the case of integral-fin tube (i.e. using R-141b as a test fluid where retention angle is greater than 90° at low approaching zero vapour velocity) retention angle decreased with increasing vapour velocity

  12. Flexibilidad laboral: ¿fin del trabajo permanente?

    Carmen Añez Hernández

    2016-05-01

    Full Text Available Los trabajos transitorios o atípicos, siguen posicionándose y funcionando trastocando la protección del sistema de regulación y protección del trabajo permanente. De ahí, la importancia de reflexionar teóricamente sobre el tema. Para su desarrollo se plantean los siguientes objetivos: demostrar que la flexibilización laboral ha incidido en la ruptura de las relaciones laborales, caracterizar como la subcontratación laboral encubre dichas relaciones, analizar el despido laboral y sus consecuencias en los trabajadores. El artículo se desarrolló teóricamente, especialmente tomando como referencia autores como: Bravo (2010, Quintero (2010, González (2012 De La Garza (2007, Ugarte (2007, entre otros, lo cual permitió analizar la temática abordada. Los resultados reflejan que dicha estrategia está impulsando la agudización de las condiciones precarias de los derechos laborales, con lo cual se está ante un capitalismo irracional, que tiene como propósito que los trabajadores sufraguen los efectos de las pretensiones de los capitalistas por conseguir mayores tasas de ganancia y niveles más altos de productividad. En consecuencia, la flexibilización de las relaciones laborales está destinada a ocultar los derechos de los trabajadores, agudizar el despido laboral, y propiciar el fin de un trabajo permanente.

  13. CFD-based Analysis of Aeroelastic behavior of Supersonic Fins

    Tianxing Cai

    2011-02-01

    Full Text Available The main goal of this paper is to analyze the flutter boundary, transient loads of a supersonic fin, and the flutter with perturbation. Reduced order mode (ROM based on Volterra Series is presented to calculate the flutter boundary, and CFD/CSD coupling is used to compute the transient aerodynamic load. The Volterra-based ROM is obtained using the derivative of unsteady aerodynamic step-response, and the infinite plate spline is used to perform interpolation of physical quantities between the fluid and the structural grids. The results show that inertia force plays a significant role in the transient loads, the moment cause by inertia force is lager than the aerodynamic force, because of the huge transient loads, structure may be broken by aeroelasticity below the flutter dynamic pressure. Perturbations of aircraft affect the aeroelastic response evident, the reduction of flutter dynamic pressure by rolling perturbation form 15.4% to 18.6% when Mach from 2.0 to 3.0. It is necessary to analyze the aeroelasticity behaviors under the compositive force environment.

  14. Latitude and longitude vertical disparity

    Read, Jenny C. A.; Phillipson, Graeme P.; Glennerster, Andrew

    2009-01-01

    The literature on vertical disparity is complicated by the fact that several different definitions of the term “vertical disparity” are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparity. Near the fixation point, these definitions become equivalent, but in general, they have quite d...

  15. Latitude and longitude vertical disparities

    Read, Jenny C. A.; Phillipson, Graeme P.; Glennerster, Andrew

    2009-01-01

    The literature on vertical disparity is complicated by the fact that several different definitions of the term “vertical disparity” are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparities. Near the fixation point, these definitions become equivalent, but in general, they have quite...

  16. Vertical distribution of minor and trace elements by neutron activation instrumental analysis in estuary sediments of Santos e Sao Vicente, Sao Paulo State, Brazil

    Santos and Sao Vicente estuaries, located in Sao Paulo State, Southeast Brazil, comprises one of the most important industrial regions of the country. Such activities contribute for the enhancement of pollutants in the environment. The impact arising form the transport and accumulation of chemical substances, e.g. heavy metals, as well as the mechanisms of these processes are not fully understood. In this sense, much attention has been paid for the effluent discharges enriched by chemical elements in the near shore environment. The elements As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Se, Ta and Zr were analyzed in 27 sediment sample from Santos and Sao Vicente Estuary and from Santos Bay, aiming to determine the horizontal distribution of these elements. The obtained results was analyzed by means of Pearson correlation coefficient and cluster analyses. The utilization of a normalizer element is also discussed. (author)

  17. A robotic device with a passive undulating ribbon fin: kinematics and propulsive performance

    Liu, Hanlin; Curet, Oscar

    2015-11-01

    Many aquatic animals swim with high maneuverability using undulating ribbon fins. In this type of swimming, the organism propels by sending one or multiple traveling waves along an elongated fin. In previous work, robotic models with fully actuated fins where the parameters of the traveling waves are fully prescribed have been used to study the propulsive performance and fluid dynamics of this type of propulsion. However, less work has been done in ribbon fins with passively undulating waves. In this work, we use a robotic device to study the kinematics and propulsive performance of a passively undulating ribbon fin. The physical model is composed of fifteen rays interconnected with a membrane. Only two rays are actuated while the other rays are free to rotate through a common axis. The robotic fin was tested in a flume at different flow conditions. In a series of experiments we measured fin kinematics, propulsive forces and power consumption. As the leading two rays are actuated, a traveling wave with decaying amplitude passes through the passive rays. As the frequency of the actuated rays increases, the enclosed area of the undulating wave and the traveling wave frequency increase while the wavelength decreases. Our data also show that the propulsive force generated by the fin scaled with the enclosed area and the square of the relative velocity between incoming flow and traveling wave. These results suggest that both natural swimmers and underwater vehicles using ribbon-fin-based propulsion can potentially take advantage of passive undulating waves. National Science Foundation Grant No. 1420774

  18. Effect of caudal fin flexibility on the propulsive efficiency of a fish-like swimmer

    A computational model is used to examine the effect of caudal fin flexibility on the propulsive efficiency of a self-propelled swimmer. The computational model couples a penalization method based Navier–Stokes solver with a simple model of flow induced deformation and self-propelled motion at an intermediate Reynolds number of about 1000. The results indicate that a significant increase in efficiency is possible by careful choice of caudal fin rigidity. The flow-physics underlying this observation is explained through the use of a simple hydrodynamic force model and guidelines for bioinspired designs of flexible fin propulsors are proposed. (paper)

  19. Thermal performance analysis of optimized hexagonal finned heat sinks in impinging air jet

    Yakut, Kenan; Yeşildal, Faruk; Karabey, Altuǧ; Yakut, Rıdvan

    2016-04-01

    In this study, thermal performance analysis of hexagonal finned heat sinks which optimized according to the experimental design and optimization method of Taguchi were investigated. Experiments of air jet impingement on heated hexagonal finned heat sinks were carried out adhering to the L18(21*36) orthogonal array test plan. Optimum geometries were determined and named OH-1, OH-2. Enhancement efficiency with the first law of thermodynamics was analyzed for optimized heat sinks with 100, 150, 200 mm heights of hexagonal fin. Nusselt correlations were found out and variations of enhancement efficiency with Reynolds number presented in η-Re graphics.

  20. The fin-to-limb transition as the re-organization of a Turing pattern

    Onimaru, Koh; Marcon, Luciano, 1983-; Musy, Marco; TANAKA, MIKIKO; Sharpe, James

    2016-01-01

    A Turing mechanism implemented by BMP, SOX9 and WNT has been proposed to control mouse digit patterning. However, its generality and contribution to the morphological diversity of fins and limbs has not been explored. Here we provide evidence that the skeletal patterning of the catshark Scyliorhinus canicula pectoral fin is likely driven by a deeply conserved Bmp–Sox9–Wnt Turing network. In catshark fins, the distal nodular elements arise from a periodic spot pattern of Sox9 expression, in co...

  1. Numerical Study on the Effect of Tube Rows on the Heat Transfer Characteristic of Dimpled Fin

    Xuehong Wu; Lihua Feng; Dandan Liu; Hao Meng; Yanli Lu

    2014-01-01

    The dimpled fin has excellent heat transfer performance and has attracted a lot of attention to apply on the fin and tube heat exchanger. A study presents to investigate the effects of number of tube rows on the air-side heat transfer characteristics of dimpled fin for velocity ranging from 1 to 3 m/s. The Q/ΔP and Q/(ΔP×V) are used to evaluate the heat transfer performance of the heat exchanger. The results show that the dimpled arrangement can change the mainstream direction, increase the d...

  2. Fin whale vocalizations observed with ocean bottom seismometers of cabled observatories off east Japan Pacific Ocean

    Iwase, Ryoichi

    2015-07-01

    Fin whale vocalizations were found in the archived waveform data from both hydrophones and ocean bottom seismometers (OBSs) of a cabled observatory off Kushiro-Tokachi in Hokkaido. A fin whale was localized on the basis of the incident orientation estimated with a single OBS and the time difference of multipath arrival of sound pressure data from a hydrophone. Furthermore, several fin whale vocalizations were found in the archived OBS waveform data from other cabled observatories off east Japan Pacific Ocean. These findings suggest that the cabled OBSs would be significant apparatuses for real-time monitoring of the presence of baleen whales around Japan.

  3. Experimental Analysis Of Heat Transfer From Square Perforated Fins In Staggered Arrangement

    Siddiqui. M. Abdullah; Dr. A. T. Autee

    2015-01-01

    This project gives the experimental analysis of heat transfer over a flat surface equipped with Square perforated pin fins in staggered arrangement in a rectangular channel. The Fin dimensions are 100mm in height & 25mm in width. The range of Reynolds number is fixed & about 13,500– 42,000, the clearance ratio (C/H) 0, 0.33 and 1, the inter-fin spacing ratio (Sy /D) 1.208, 1.524, 1.944 and 3.417. Sy i.e. stream wise distance is varies and Sx i.e. span wise distance is constant. Th...

  4. Classical Lie Point Symmetry Analysis of a Steady Nonlinear One-Dimensional Fin Problem

    R. J. Moitsheki

    2012-01-01

    Full Text Available We consider the one-dimensional steady fin problem with the Dirichlet boundary condition at one end and the Neumann boundary condition at the other. Both the thermal conductivity and the heat transfer coefficient are given as arbitrary functions of temperature. We perform preliminary group classification to determine forms of the arbitrary functions appearing in the considered equation for which the principal Lie algebra is extended. Some invariant solutions are constructed. The effects of thermogeometric fin parameter and the exponent on temperature are studied. Also, the fin efficiency is analyzed.

  5. The combined effect of radiation and convection on the efficiency of conductive single plate fins

    The efficiencies of conductive single-plate fins transferring waste heat by convection and radiation were determined. The solution of the nonlinear differential equation governing the steady-state temperature distribution on the fin surface was found to depend upon four parameters. Numerical means were used, and the results analysed and compared with particular cases. Typical temperature profiles revealed that there are certain values of the parameters for which the fin can dissipate heat by radiation, while receiving heat by convection. Also, it was found that the efficiency decreases as the convection and radiation parameters increase. (Author)

  6. Vertical and wide-angle seismic exploration of crustal structure, and the active evolution of the North Aegean Trough between the Sea of Marmara and Gulf of Corinth

    Sachpazi, M.; Vigner, A.; Laigle, M.; Hirn, A.; Roussos, N.

    2003-04-01

    The North Aegean Trough (NAT), which is the deepest among Aegean marine troughs, is bordered by the termination of the North Anatolian Fault, and thus marks the interaction of this strike-slip fault with mainland Greece and the extensional Aegean domain. In the development of academic exploration of active regions at the scale of the whole crust, with marine multichannel seismics (MCS), the STREAMERS acquisition almost ten years ago provided a first hint of the feasibility there and in other parts of the Aegean and Ionian seas (Sachpazi et al., Tectonophysics 1996), and a template for later MCS and coincident wide-angle reflection surveying. These profiles were acquired by the French N/O Nadir, with an only 96-channel streamer 2.4 km length, and with an only 840 cu. in. generator capacity of a 8 gun array, but for the first time shot in the "single-bubble" mode that was developed in this survey. With respect to the present standard set by 2001 cruises in the Gulf of Corinth (US R/V Maurice Ewing, Taylor et al. this meeting) and in the Sea of Marmara (French N/O Nadir, Hirn et al., EGS 2002 and this meeting) this was a 2 to 3 times shorter streamer cable, a 2 to 4 times smaller number of hydrophone groups, and a 10 to 3 times smaller source. The SEISGREECE survey, with a source 3 times that of STREAMERS but other parameters as modest, explored the Gulf of Corinth and the Cyclades and added profiles in the North Aegean to this early attempt. A first result of merging the two surveys was to lend credence to possible structures detected by the first single profile. This revealed an active, recent normal-fault imaged down to 10 km depth, that cuts at a N 110°E strike the northern side of the NAT (Laigle et al., Geology, 2000). Indeed although processing has been hampered by the modest streamer length and only 16 or 24-fold coverage, the data now resolve clearly the sedimentary structure, image the basement, detect intra-basement faults, an upper crustal reflective zone

  7. Vertically reciprocating auger

    Etheridge, Mark; Morgan, Scott; Fain, Robert; Pearson, Jonathan; Weldi, Kevin; Woodrough, Stephen B., Jr.

    1988-01-01

    The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input.

  8. Vertical 2D Heterostructures

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  9. Vertical separation for TCF

    The authors studied an insertion for electrostatic separation of the electron and positron beams with the aims of: increasing luminosity by decreasing the minimum bunch spacing, matching the vertical dispersion function (not done in the Jowett lattice). The authors looked at three possibilities for the start of the insertion: a quadrupole doublet followed by the electrostatic separator (Jowett), a quadrupole doublet with the electrostatic separator between the two quadrupoles (Kamada), a separator followed by a quadrupole doublet. The third possibility was immediately discharged. Although possible for a B-factor with magnetic separation it is impractical for use with electrostatic separation because of the length and cross section of separator required. The Kamada scheme looked promising for getting very short inter-bunch spacing, but suffered from the disadvantage of requiring a very large ratio of beta functions at the Interaction Point (IP) (βx*/βy* = 100). (They would rather have a β* ratio closer to 20 to 1). They decided to persue the doublet scheme to see whether it could match the performance of Kamada insertion. They assumed superconducting magnets could be used for the insertion quadrupoles, and they used as strong an electrostatic field for the separator as Kamada

  10. Vertical guidance of shearers

    Mining Engineers have always been aware of the basic need to avoid contamination of the mined product, by controlling the cutting horizon at the coal face. The ability to maintain the optimum cutting horizon results in more effective roof control and ensures a safer and more efficient working environment, for men and machinery. The cost of treatment in the surface coal preparation plant is reduced. Transportation through the total mine system of material finally destined for the spoil heap is minimised. A reduction in product contamination is achieved and makes more effective use of the mine capacity. These benefits make possible significant improvements in productivity and financial returns. Exploitation of micro computer based systems has enabled the successful development of equipment which employs sensors to detect the very low natural gamma radiation from roof strata; to determine and allow control of the position of the cut relative to the roof and floor. This paper reviews the experience gained by the National Coal Board, particularly in South Yorkshire Area, with the vertical steering of ranging drum shearers. It outlines the benefits and considers the future for this technology and its contribution to total coal face automation

  11. FIN13, a novel growth factor-inducible serine-threonine phosphatase which can inhibit cell cycle progression.

    Guthridge, M A; Bellosta, P; Tavoloni, N; Basilico, C.

    1997-01-01

    We have identified a novel type 2C serine-threonine phosphatase, FIN13, whose expression is induced by fibroblast growth factor 4 and serum in late G1 phase. The protein encoded by FIN13 cDNA includes N- and C-terminal domains with significant homologies to type 2C phosphatases, a domain homologous to collagen, and an acidic domain. FIN13 expression predominates in proliferating tissues. Bacterially expressed FIN13 and FIN13 expressed in mammalian cells exhibit serine-threonine phosphatase ac...

  12. Magnetic Heat Transfer Enhancements on Fin-Tube Heat Exchangers

    Yan SU; C.T. HSU

    2007-01-01

    通过DNS方法解耦合的三维非稳态流动和固流体能量方程组,本文研究了两平行磁质平板和圆管所组成的肋片式圆管换热器单元与震荡流体间的传热过程.对不同的磁场频率和振幅的三维动态流热场的模拟结果表明增强磁场频率和振幅能很有效地增加周期平均传热强度达到强化传热的目的.%Two narrowly-gapped magnetic parallel plates embedding a circular disk was considered as a unit-cell to represent the fin-tube heat exchanger where heat from a circular tube was dissipated by a series of parallel equally-spaced thin plates in normal to the tube. The unsteady 3-D continuity,Navier-Stokes and energy equations for fluids and solids describing the convective heat transfer for the unit-cell geometry were solved numerically with DNS method. The present study aims on using oscillating flows and magnetic fields to enhance the heat transfer for various amplitudes and frequencies of the magnetic field. Results from cycle-averaged heat fluxes from the cylinder wall show that the increase in magnetic amplitude and frequency will greatly enhance the heat transfer. The effects of the oscillating magnetic field were discussed and the three dimensional flow and temperature fields were also presented.

  13. Experimental research of inclined-micro-fin flat tube on single phase convection heat transfer

    The experimental research of heat transfer and flow resistance characteristics of single phase water in four inclined-micro-fin flat tubes with different physical dimensions was conducted. At the same time,suitable criteria were selected to evaluate the efficiency of inclined-micro-fin flat tubes within the experimental scope and the optimal working region was determined. The results indicate that inclined-micro-fin flat tubes can greatly enhance the single-phase heat transfer in turbulent flow and the maximum heat transfer coefficient attains to 5.9 times of that in smooth tube. The quantities of heat transfer for inclined-micro-fin flat tubes are three times higher than that of smooth tube with the same of heat exchange area and pump power. (authors)

  14. Analytical Thermal and Cost Optimization of Micro-Structured Plate-Fin Heat Sink

    Rezaniakolaei, Alireza; Rosendahl, Lasse

    Microchannel heat sinks have been widely used in the field of thermo-fluids due to the rapid growth in technological applications which require high rates of heat transfer in relatively small spaces and volumes. In this work, a micro plate-fin heat sink is optimized parametrically, to minimize the...... thermal resistance and to maximize the cost performance of the heat sink. The width and the height of the microchannels, and the fin thickness are analytically optimized at a wide range of pumping power. Using an effective numeric test, the generated equations also discuss the optimum parameters at three...... sizes of the substrate plat of the heat sink. Results show that, at any pumping power there are specific values of the channel width and fin thickness which produce minimum thermal resistance in the heat sink. The results also illustrate that, a larger channel width and a smaller fin thickness lead to a...

  15. A Comparative Study of Conventional and Tip-Fin Propeller Performance

    Andersen, Poul

    1997-01-01

    During more than a decade several attempts have been made to obtain higher propeller efficiencies by radically modifying the geometry in the tip region of the blade. In the tip-fin propeller a tip fin or winglet is attached to the blade tip and integrated into the blade in such a way that the blade...... tip is softly curved towards the suction side.Whereas the developments previously have been concentrated mainly on increasing the efficiency of the propeller, the emphasis of current efforts has been on both high efficiency as well as good cavitation properties. This has resulted in a design with a...... combination of skew and tip fin. To evaluate the design, open-water, self-propulsion and cavitation model tests have been carried out. The tests are done for the conventional propeller originally designed for the ship and for a tip-fin propeller designed for the same ship under the same operation conditions...

  16. Thermal analysis of annular fins with temperature-dependent thermal properties

    I. G. AKSOY

    2013-01-01

    The thermal analysis of the annular rectangular profile fins with variable thermal properties is investigated by using the homotopy analysis method (HAM). The thermal conductivity and heat transfer coefficient are assumed to vary with a linear and power-law function of temperature, respectively. The effects of the thermal-geometric fin parameter and the thermal conductivity parameter variations on the temperature distribution and fin efficiency are investigated for different heat transfer modes. Results from the HAM are compared with numerical results of the finite difference method (FDM). It can be seen that the variation of dimensionless parameters has a significant effect on the temperature distribution and fin efficiency.

  17. Thermal-hydraulic performance of the finned surface of a compact heat exchanger

    In this work the thermal-hydraulic behavior of the finned surface of a compact heat exchanger is obtained in tube-fin configuration corrugated (wavy). Through numerical simulation are determined average values ​​of intensification of heat transfer and pressure loss in the inter-channel finned. The objective is to characterize the surface to use as a reference, to make comparisons with other heat exchange surfaces enhanced using traditional techniques combined with more current, such as vortex generators. The study is conducted in laminar flow, with Reynolds numbers below 1000. In the working model compact exchanger tubes and corrugated fins (wavy) heat is described, and the results of the coefficient of overall heat transfer and the pressure drop are explained from the local characteristics of the velocity field and temperature inside the heat exchanger. (Full text)

  18. Simulation on Thermal Integrity of the Fin/Tube Brazed Joint of Heat Exchangers

    Yiyu QIAN; Feng GAO; Fengjiang WANG; Hui ZHAO

    2003-01-01

    In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the therma

  19. DNR 100K Lakes - Fishing in the Neighborhood (FiN) Ponds

    Minnesota Department of Natural Resources — This layer represents ponds included in DNR's Fishing in the Neighborhood (FiN) program. This program establishes local ponds to provide urban fishing opportunities...

  20. Supersonic aerodynamic characteristics of a series of wrap-around-fin missile configurations

    Fournier, R. H.

    1977-01-01

    A parametric study of wrap-around-fin missile configurations was conducted at Mach numbers from 1.60 to 2.86 in the Langley Unitary Plan wind tunnel. The fin configurations investigated included variations in chord length, leading edge sweep, thickness ratio, and leading edge shape. The investigation also included a smooth and a stepped-down afterbody required for flush retraction of the wrap-around-fin configuration. The investigation indicated no unusual longitudinal characteristics; however, all the wrap-around-fin configurations tested indicated erratic lateral behavior, particularly in the form of induced roll at zero angle of attack and irregular variations of roll with angle of attack and Mach number. The magnitude of rolling moment at an angle of attack of 0 deg is estimated to represent approximately 0.25 deg or less roll control deflection. The stepped-down afterbody has a marked effect on reducing the induced roll.

  1. Control characteristics for wrap-around fins on cruise missiles configurations

    Sawyer, W. C.; Monta, W. J.; Carter, W. V.; Alexander, W. K.

    1981-01-01

    This paper presents selected results of a panel loads study conducted as part of the final phase of an extensive investigation of an air-breathing missile concept employing wrap-around aerodynamic surfaces. Typical results for M = 2.36 are presented for the fin load results, plus a brief review of basic results of the previously reported tests. Vapor screen results are also discussed. The present results indicate that the fin load characteristics are nearly identical for planar and curved fins having the same projected planform and would permit the use of planar-surface predictions for supersonic speeds in the preliminary design stages of missiles employing wrap-around curved fins.

  2. Comparative Study for Improving the Thermal and Fluid Flow Performance of Micro Channel Fin Geometries Using Numerical Simulation

    S.Subramanian

    2015-07-01

    Full Text Available There is a continuous quest for improving the performance of micro channels for handling the increased dissipation of heat from electronics circuits. The Oblique fin micro channels are attractive as they perform better than plate fin & pin fin configurations. There are scopes for further improvements in oblique fin micro channels. Hence this work is about the investigation for the performance enhancement by modifying the oblique fin geometry. Seven variants of micro channel geometries have been explored using three dimensional numerical simulations. The variants are plate fin, in-line pin fin, staggered pin fin, oblique fin, oblique fin with two slit angles, oblique with nozzle type slit and improved oblique fin. The simulation results are validated using the published data. To ensure a common reference for comparison, hydraulic diameter, inlet flow conditions, heat loads and the boundary conditions are kept identical across all the geometries. The results of simulation are compared for the thermal & fluid flow performances. Heat transfer correlations have been developed using the simulation data. The proposed modification is found to enhance the performance significantly

  3. Influence of Alumina Addition to Aluminum Fins for Compact Heat Exchangers Produced by Cold Spray Additive Manufacturing

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

    2015-10-01

    In this work, aluminum and aluminum-alumina powder mixtures were used to produce pyramidal fin arrays on aluminum substrates using cold spray as an additive manufacturing process. Using aluminum-alumina mixtures instead of pure aluminum powder could be seen as a cost-effective measure, preventing nozzle clogging or the need to use expensive polymer nozzles that wear out rapidly during cold spray. The fin geometries that were produced were observed using a 3D digital microscope to determine the flow passages width and fins' geometric details. Heat transfer and pressure drop tests were carried out using different ranges of appropriate Reynolds numbers for the sought commercial application to compare each fin array and determine the effect of alumina content. It was found that the presence of alumina reduces the fins' performance when compared to pure aluminum fins but that they were still outperforming traditional fins. Numerical simulations were performed to model the fin arrays and were used to predict the pressure loss in the fin array and compare these results with experimental values. The numerical model opens up new avenues in predicting different applicable operating conditions and other possible fin shapes using the same fin composition, instead of performing costly and time-consuming experiments.

  4. Research and Simulation of a flexible robotic fish tail fin propulsion system

    Luo Hong Yu

    2016-01-01

    Full Text Available This article uses a flexible crescent caudal fin tuna as the research object, sets up the robot fish physical model ,researches the propulsion and advancing speed of the model, discusses forward speed, sliding and swing amplitude, frequency and phase to the flexible tail fin propulsive performance, and uses MATLAB to simulate, motion simulation is consistent with the way to achieve the real movement of the fish.

  5. Shark Fin Test und rheologische Eigenschaften von elastomeren Abformmaterialien : eine Korrelationsanalyse

    Stelzig, Jürgen

    2009-01-01

    Es war das Ziel dieser Arbeit, die Ergebnisse des Shark Fin Tests mit Hilfe von rheologischer Kenngrößen dentaler Abformmaterialien zu beschreiben. Es wurden acht Abformmaterialien, vier Polyether und jeweils zwei A-Silikone und Hybridmaterialien untersucht. Die Prüfung der rheologischen Eigenschaften (komplexe Viskosität, Nullviskosität und Fließgrenze) wurden mit Hilfe eines Rheo Stress 600 Rheometers (Thermo/ Fisher Scientific, Karlsruhe), der Shark Fin Test mit einer Shark ...

  6. Fin Fish Biodiversity Of A Tropical Sal Estuary, Goa, West Coast Of India

    Nandadeep U. Fal Dessai

    2013-01-01

    Sal estuary represents rich biodiversity because of the heavy rains during the south west monsoon and lack of any industrial development along the banks of the river. Attempt was made to survey the fin fish biodiversity along the estuary to fulfill the lack of adequate information regarding estuarine fisheries. Hydrological parameters were analysed during the study period and found to be highly influencing. Fishes were caught near shore by using gill nets and cast nets. About 35 fin fishes we...

  7. Collector Efficiency in Downward-Type Internal-Recycle Solar Air Heaters with Attached Fins

    Chii-Dong Ho; Ho-Ming Yeh

    2013-01-01

    The internal-recycle operation effect on collector efficiency in downward-type rectangular solar air heaters with attached fins is theoretically investigated. It is found that considerable collector efficiency is obtainable if the collector has attached fins and the operation is carried out with internal recycling. The recycling operation increases the fluid velocity to decrease the heat transfer resistance, compensating for the undesirable effect of decreasing the heat transfer driving force...

  8. Numerical and experimental study of the performance of a drop-shaped pin fin heat exchanger

    Boulares, Jihed

    2003-01-01

    Approved for public release; distribution is unlimited. This research presents the results of a combined numerical and experimental study of heat transfer and pressure drop behavior in a compact heat exchanger (CHE) designed with drop-shaped pin fins. A numerical study using ANSYS was first conducted to select the optimum pin shape and configuration for the CHE. This was followed by an experimental study to validate the numerical model. The results indicate that the drop shaped pin fins ...

  9. Establishment of a turbot fin cell line and its susceptibility to turbot reddish body iridovirus

    Fan, Ting-Jun; Ren, Bing-Xin; Geng, Xiao-Fen; Yu, Qiu-Tao; Li-yan WANG

    2010-01-01

    A turbot, Scophthalmusmaximus, fin (TF) cell line was established and susceptibility to turbot reddish body iridovirus (TRBIV) was determined in this study. Primary culture of TF cells was initiated from fin tissue pieces partially digested with trypsin, collagenase II and hyaluronidase. Digested tissue pieces were cultured at 24 °C in Leibovitz-15 medium (pH 7.2), supplemented with 20% fetal bovine serum, carboxymethyl chitosan, N-acetylglucosamine hydrochloride, basic fibroblast growth fact...

  10. Was the tail bud the ancestral centre where the fin developmental program evolved in chordates?

    Cotoras, D.D.; M.L. Allende

    2015-01-01

    The structural origin of the vertebrates’ paired limbs is still an unsolved problem. Historically, two hypotheses have been raised to explain the origin of vertebrate limbs: the Archipterygium Hypothesis and the Fin Fold Hypothesis. Current knowledge provides support for both ideas. In the recent years, it has been also suggested that (1) all appendages correspond to body axis duplications and (2) they are originated by the ventralization of the developmental program present in the median fin...

  11. Development of a Methodology to Measure Aerodynamic Forces on Pin Fins in Channel Flow

    Brumbaugh, Scott J

    2006-01-01

    The desire for smaller, faster, and more efficient products places a strain on thermal management in components ranging from gas turbine blades to computers. Heat exchangers that utilize internal cooling flows have shown promise in both of these industries. Although pin fins are often placed in the cooling channels to augment heat transfer, their addition comes at the expense of increased pressure drop. Consequently, the pin fin geometry must be judiciously chosen to achieve the desired he...

  12. Origin of fin-clipped salmonids collected at two thermal discharges on Lake Michigan

    Fin clips observed on fish collected during tagging studies at the Point Beach and Waukegan thermal discharges were recorded and the data were tabulated by species. Using fin clip and fish size, attempts were made to identify probable stocking locations and dates from agency records. Data are presented for lake trout, rainbow trout, brown trout, and Coho salmon. Tables are presented to show probable stocking locations and dates

  13. Studi Eksperimen Analisa Performa Compact Heat Exchanger Louvered Fin Flat Tube untuk pemanfaatan Waste Energy

    Taqwim Ismail; Ary Bachtiar Khrisna Putra

    2014-01-01

    Waste Heat Recovery merupakan instalasi yang digunakan untuk memanfaatkan kembali waste energy seperti exhaust gas. Penelitian dilakukan pada compact heat exchanger tipe louvered fin flat tube sebagai salah satu komponen penyusun waste heat recovery system. Eksperimen dilakukan dengan mendesain compact heat exchanger tipe louvered fin flat tube kemudian dilakukan pengujian pada compact heat exchanger yang telah didesain. Pengujian dilakukan dengan memberikan tiga variasi kecepatan putaran fan...

  14. Diversification of the pectoral fin shape in damselfishes (Perciformes, Pomacentridae) of the Eastern Pacific

    Aguilar-Medrano, Rosalia; Frederich, Bruno; Eduardo F. Balart; De Luna, Efrain

    2013-01-01

    Fin shape strongly influences performance of locomotion across all swimming styles. In this study, we focused on the diversity of the pectoral fin morphology in damselfishes of the Eastern Pacific. Underwater observations and a review of literature allowed the characterization of ten behavioral groups. Territorial and non-territorial species were discriminated easily with traditional morphometrics. Five ecomorphological groups were recognized by geometric morphometric analyses. Geometric data...

  15. Solidification of binary alloy in a finned enclosure from the bottom

    Tan, F.L. [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore)

    2009-01-15

    This paper presents experimental findings on the phenomenon of solidification of a binary alloy in a finned enclosure using aqueous ammonium chloride solution. Solidification experiments are carried out over a wide range of initial composition of binary alloy solution from hypoeutectic to hypereutectic concentration ranging from 8, 16 and 24% of ammonium chloride are discussed. An interesting ''snowing'' phenomenon is observed for the hypereutectic concentration in a finned enclosure. (orig.)

  16. Out-of-plane strain effect on silicon-based flexible FinFETs

    Ghoneim, Mohamed T.

    2015-06-21

    Summary form only given. We report out-of-plane strain effect on silicon based flexible FinFET, with sub 20 nm wide fins and hafnium silicate based high-κ gate dielectric. Since ultra-thin inorganic solid state substrates become flexible with reduced thickness, flexing induced strain does not enhance performance. However, detrimental effects arise as the devices are subject to various out-of-plane stresses (compressive and tensile) along the channel length.

  17. Shape optimization of rotating rectangular channels with pin-fins by kriging method

    This paper presents numerical optimization of the design of a rotating rectangular channel with staggered arrays of pin-fins with Kriging metamodeling technique. Two non-dimensional variables, the ratio of the height to diameter of the pin-fin and the ratio of the spacing between the pin-fins to diameter of the pin-fins are chosen as design variables. The objective function as a linear combination of heat transfer and friction loss related terms with a weighting factor is selected for the optimization. Objective function values at twenty training points generated by Latin Hypercube Sampling (LHS) are evaluated by three-dimensional ReynoldsAveraged Navier-Stokes (RANS) method with the Shear Stress Transport (SST) turbulence model. The prediction of objective function by Kriging metamodeling at optimum point shows reasonable accuracy in comparison with the values calculated by RANS analysis. With increase in height of the pin-fin, heat transfer is decreased and at the same time pressure drop is also decreased, while opposite behavior is obtained for the pin-fin spacing.

  18. Cooling Effect Improvement by Dimensional Modification of Annular Fins in Two Stage Reciprocating Compressor

    Mr. Ashish D. Vasiyar,

    2014-05-01

    Full Text Available The Reciprocating Compressor fins are made from Aluminum alloy and it is provided for increase in contact area in convective heat transfer. Air cooling is a method of dissipating heat It works by making the object to be cooled have a larger surface area or have an increased flow of air over its surface. a fin is a surface that extends from an object to increase the rate of heat transfer to or from the environment by increasing convection. The aim of present work study is to prepare a finite element model of fin. The result of finite element model will be verified with experimental work with thermocouple. After comparing results of FEA model we can modify boundary condition, material shape & size for improvement in efficiency & cooling rate. It is possible to find optimum solution with FEA package ANSYS 14 used for modeling and analysis. Effectiveness of fin can be improved by changing geometry of fin. So after increase effectiveness it can increase cooling rate and minimize the time for cooling process of Reciprocating compressor. Aim of this work is increase effectiveness of the fin for best performance.

  19. Pool boiling on surfaces with mini-fins and micro-cavities

    The experimental studies presented here focused on pool boiling heat transfer on mini-fin arrays, mini-fins with perforated covering and surfaces with micro-cavities. The experiments were carried out for water and fluorinert FC-72 at atmospheric pressure. Mini-fins of 0.5 and 1 mm in height were uniformly spaced on the base surface. The copper foil with holes of 0.1 mm in diameter (pitch 0.2/0.4 mm), sintered with the fin tips, formed a system of connected perpendicular and horizontal tunnels. The micro-cavities were obtained through spark erosion. The maximal depth of the craters of these cavities was 15 – 30 μm and depended on the parameters of the branding-pen settings. At medium and small heat fluxes, structures with mini-fins showed the best boiling heat transfer performance both for water and FC-72. At medium and high heat fluxes (above 70 kW/m2 for water and 25 kW/m2 for FC-72), surfaces with mini-fins without porous covering and micro-cavities produced the highest heat transfer coefficients. The surfaces obtained with spark erosion require a proper selection of geometrical parameters for particular liquids – smaller diameters of cavities are suitable for liquids with lower surface tension (FC-72).

  20. Mechanism of Tonal Noise Generation from Circular Cylinder with Spiral Fin

    Ryo Yamashita; Hidechito Hayashi; Tetsuya Okumura; Hiromitsu Hamakawa

    2014-01-01

    The pitch of the spiral finned tube influences seriously to the acoustic resonance in the heat exchanger.In this research,the flow characteristics in relating to the aeolian tone from the finned cylinder are studied by the numerical simulation.It is observed that the tonal noise generated from the finned tube at two pitch spaces.The ratio of the fin pitch to the cylinder diameter is changed at 0.11 and 0.27.The tone level increases and the frequency decreases with the pitch shorter.The separation flow from the cylinder generates the span-wise vortices,Karman vortices,and the separation flow from the fin generates the stream-wise vortices.When the fin pitch ratio is small,the stream-wise vortices line up to span-wise and become weak rapidly.Only the Karman vortices are remained and integrate in span.So the Karman vortex became large.This causes the low frequency and the large aeolian tone.

  1. Indirect adaptive output feedback control of a biorobotic AUV using pectoral-like mechanical fins

    Naik, Mugdha S; Singh, Sahjendra N [Department of Electrical and Computer Engineering, University of Nevada, Las Vegas, NV 89154-4026 (United States); Mittal, Rajat [Department of Mechanical and Aerospace Engineering, George Washington University, Washington University, DC 22052 (United States)], E-mail: sahaj@egr.unlv.edu

    2009-06-01

    This paper treats the question of servoregulation of autonomous underwater vehicles (AUVs) in the yaw plane using pectoral-like mechanical fins. The fins attached to the vehicle have oscillatory swaying and yawing motion. The bias angle of the angular motion of the fin is used for the purpose of control. Of course, the design approach considered here is applicable to AUVs for other choices of oscillation patterns of the fins, which produce periodic forces and moments. It is assumed that the vehicle parameters, hydrodynamic coefficients, as well the fin forces and moments are unknown. For the trajectory control of the yaw angle, a sampled-data indirect adaptive control system using output (yaw angle) feedback is derived. The control system has a modular structure, which includes a parameter identifier and a stabilizer. For the control law derivation, an internal model of the exosignals (reference signal (constant or ramp) and constant disturbance) is included. Unlike the direct adaptive control scheme, the derived control law is applicable to minimum as well as nonminimum phase biorobotic AUVs (BAUVs). This is important, because for most of the fin locations on the vehicle, the model is a nonminimum phase. In the closed-loop system, the yaw angle trajectory tracking error converges to zero and the remaining state variables remain bounded. Simulation results are presented which show that the derived modular control system accomplishes precise set point yaw angle control and turning maneuvers in spite of the uncertainties in the system parameters using only yaw angle feedback.

  2. Indirect adaptive output feedback control of a biorobotic AUV using pectoral-like mechanical fins

    This paper treats the question of servoregulation of autonomous underwater vehicles (AUVs) in the yaw plane using pectoral-like mechanical fins. The fins attached to the vehicle have oscillatory swaying and yawing motion. The bias angle of the angular motion of the fin is used for the purpose of control. Of course, the design approach considered here is applicable to AUVs for other choices of oscillation patterns of the fins, which produce periodic forces and moments. It is assumed that the vehicle parameters, hydrodynamic coefficients, as well the fin forces and moments are unknown. For the trajectory control of the yaw angle, a sampled-data indirect adaptive control system using output (yaw angle) feedback is derived. The control system has a modular structure, which includes a parameter identifier and a stabilizer. For the control law derivation, an internal model of the exosignals (reference signal (constant or ramp) and constant disturbance) is included. Unlike the direct adaptive control scheme, the derived control law is applicable to minimum as well as nonminimum phase biorobotic AUVs (BAUVs). This is important, because for most of the fin locations on the vehicle, the model is a nonminimum phase. In the closed-loop system, the yaw angle trajectory tracking error converges to zero and the remaining state variables remain bounded. Simulation results are presented which show that the derived modular control system accomplishes precise set point yaw angle control and turning maneuvers in spite of the uncertainties in the system parameters using only yaw angle feedback

  3. A novel mini-DNA barcoding assay to identify processed fins from internationally protected shark species.

    Andrew T Fields

    Full Text Available There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran in addition to three species listed in the early part of this century (whale, Rhincodon typus, basking, Cetorhinus maximus, and white, Carcharodon carcharias. Shark fins are traded internationally to supply the Asian dried seafood market, in which they are used to make the luxury dish shark fin soup. Shark fins usually enter international trade with their skin still intact and can be identified using morphological characters or standard DNA-barcoding approaches. Once they reach Asia and are traded in this region the skin is removed and they are treated with chemicals that eliminate many key diagnostic characters and degrade their DNA ("processed fins". Here, we present a validated mini-barcode assay based on partial sequences of the cytochrome oxidase I gene that can reliably identify the processed fins of seven of the eight CITES listed shark species. We also demonstrate that the assay can even frequently identify the species or genus of origin of shark fin soup (31 out of 50 samples.

  4. A novel mini-DNA barcoding assay to identify processed fins from internationally protected shark species.

    Fields, Andrew T; Abercrombie, Debra L; Eng, Rowena; Feldheim, Kevin; Chapman, Demian D

    2015-01-01

    There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran) in addition to three species listed in the early part of this century (whale, Rhincodon typus, basking, Cetorhinus maximus, and white, Carcharodon carcharias). Shark fins are traded internationally to supply the Asian dried seafood market, in which they are used to make the luxury dish shark fin soup. Shark fins usually enter international trade with their skin still intact and can be identified using morphological characters or standard DNA-barcoding approaches. Once they reach Asia and are traded in this region the skin is removed and they are treated with chemicals that eliminate many key diagnostic characters and degrade their DNA ("processed fins"). Here, we present a validated mini-barcode assay based on partial sequences of the cytochrome oxidase I gene that can reliably identify the processed fins of seven of the eight CITES listed shark species. We also demonstrate that the assay can even frequently identify the species or genus of origin of shark fin soup (31 out of 50 samples). PMID:25646789

  5. Experimental and numerical investigation to evaluate the performance of triangular finned tube heat exchanger

    Vinous M. Hameed, Bashar Muslem Essa

    2015-01-01

    Full Text Available Experimental and numerical investigation has been performed in this work to evaluate the performance for triangular finned tube heat exchanger. Experimental work included designing and manufacturing of shaped triangular fins from copper material of (10mm length, (10mm height, (1mm thickness, (22 mm distance between every two fins shaped and (15mm pitch between each two of fins which are install on the straight copper tube of (2m length having (20mm inner diameter and (22mm outer diameter. The inner tube is inserted inside the Perspex tube of (54mm inner diameter and (60mm outer diameter. Cold Air and hot water are used as working fluids in the shell side and tube side, respectively. Air at various mass flow rates (0.001875 to 0.003133 kg/sec flows through annuli and water at Reynold's numbers ranging from (10376.9 to 23348.03 flows through the inner tube. Performance of (smooth and finned tube heat exchanger was investigated experimentally. Experimental results showed that the enhancement of heat dissipation for triangular finned tube is (3.252 to4.502 times than that of smooth tube respectively. Numerical simulation has been carried out on present heat exchanger to analyze flow field and heat transfer using COMSOL computational fluid dynamic (CFD package model. The comparison between experimental work and numerical results showed good agreement.

  6. A new nanoscale fin field effect transistor with embedded intrinsic region for high temperature applications

    Karimi, Fa.; Orouji, Ali A.

    2016-08-01

    The present paper reveals a novel structure of nanoscale Silicon-On-Insulator (SOI) Fin Field Effect Transistor (FinFET) in which an intrinsic region (EIR) is embedded into the buried oxide layer. The key idea in this work is to improve the critical thermal problems raised by the self-heating effect (SHE). The EIR-FinFET device has lower thermal resistance, reduced hot carrier effect, lower threshold voltage roll-off, and lower critical electric field in comparison with the C-FinFET. Also, higher DC transconductance, lower DC conductance and a better gate capacitance are obtained because the intrinsic region is embedded in a suitable place. Moreover, the simulation result with three-dimensional and two-carrier device simulator demonstrates an improved output characteristic of the proposed structure due to the reduced self-heating effect. The intrinsic silicon layer is located under the source and fin regions and provides more space to dissipate the accumulated heat. Due to the high thermal conductivity of the silicon and decreasing corner effects there, the heat will flow easily and the lattice temperature will decrease. All the extracted results attempt to show the superiority of the EIR-FinFET device over the conventional one, and its effect on the operation of nanoscale low power and high speed devices.

  7. EXPERIMENTAL INVESTIGATION AND COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF MISSILE WITH GRID FIN IN SUBSONIC FLOW

    K.Mohamed Bak

    2010-11-01

    Full Text Available The present work deals with the investigation of aerodynamic force coefficients and flow field structure in subsonic flow on missile configuration with grid fin using Wind tunnel and CFD. The experimental work has been performed using the low speed wind tunnel, which is having a rectangular test section of 3ft height, 4ft width and 6 ft length. Reynolds number range for the models are Re = 4.79 x 105 to 1.3 x 106 and tested for different angle of attack ranging from –15 to +15. Grid fin usually produce much higher lifting forces and pitching moments to overcome the drag, which are created at high angle of attack operations. CFD is used for the prediction of aerodynamic force coefficients and flow field structure around missile with grid fin is investigated for subsonic flow. The work involves computational analysis using CFD and validating the results using wind tunnel test. The body with grid fin configuration produces the greater normal force coefficient at various angles of attack thanplanar. The axial force coefficient on the grid fin missile configuration was about 0.8 times greater than planar. The computational results of grid fin from the software package are compared with wind tunnel test data and measured data was observed for missile.

  8. Variation in Spot and Stripe Patterns in Original and Regenerated Zebrafish Caudal Fins.

    Anorve-Andress, Kyle; Arcand, Amy Lucille; Borg, Bethanie R; Brown, Jayce Lee; Chartrand, Caitlin A; Frank, Marisohn L; Jansen, Jedediah N; Joyce, Michael J; Joyce, Michael T; Kinney, Joseph A; Kruggel, Spencer Lee; Lecy, Amanda D; Ma, Phyo; Malecha, Katchen M; Melgaard, Kelsey; Miller, Paula L; Nelson, Kristina K; Nieto Robles, Marvin; Perosino, Tianna Ruth; Peterson, Jenna Marie; Rollins, April Diane; Scherkenbach, Whitney Lee; Smith, Andrea L; Sodergren, Kelsey A; Stiller, Jacob Jo; Wehber, Kevin R; Liang, Jennifer Ostrom

    2016-08-01

    Tissue regeneration requires not only the replacement of lost cells and tissues, but also the recreation of morphologies and patterns. Skin pigment pattern is a relatively simple system that can allow researchers to uncover the underlying mechanisms of pattern formation. To gain insight into how pigment patterns form, undergraduate students in the senior level course Developmental Biology designed an experiment that assayed pigment patterns in original and regenerated caudal fins of wild-type, striped, and mutant, spotted zebrafish. A majority of the WT fins regenerated with a similar striped pattern. In contrast, the pattern of spots even in the original fins of the mutants varied among individual fish. Similarly, the majority of the spots in the mutants did not regenerate with the same morphology, size, or spacing as the original fins. This was true even when only a small amount of fin was removed, leaving most of the fin to potentially reseed the pattern in the regenerating tissue. This suggests that the mechanism that creates the wild-type, striped pattern persists to recreate the pattern during regeneration. The mechanism that creates the spots in the mutants, however, must include an unknown element that introduces variability. PMID:27096743

  9. Vertical integration by oil exporting countries

    Siebert, Horst; Rauscher, Michael

    1985-01-01

    Most oil-producing countries have now nationalised their oil reserves and are pursuing their own pricing and marketing policies; in recent years some of them have attempted to extend their influence over the oil market by undertaking processing activities downstream from oil production. What motives underlie this strategy of vertical integration? What is its economic justification? What effects will it have on oil-importing countries?

  10. Vertical Collective Action: Addressing Vertical Asymmetries in Watershed Management

    Cárdenas, Juan-Camilo; Rodriguez, Luz Angela; Johnson, Nancy

    2015-01-01

    Watersheds and irrigation systems have the characteristic of connecting people vertically by water flows. The location of users along these systems defines their role in the provision and appropriation of water which adds complexity to the potential for cooperation. Verticality thus imposes a challenge to collective action. This paper presents the results of field experiments conducted in four watersheds of Colombia (South America) and Kenya (East Africa) to study the role that location plays...

  11. Mechanical properties on multi stage blazed fin body with ultra fine off-set fin for compact heat exchanger at elevated temperature

    Three-stage blazed plate fin core model of ultra fine off-set fin, -(thickness x height x pitch x off-set pitch=0.2 mm x 1.2 mm x 1.6 mm x 5 mm) blazed by Ni blazing material of the recuperator for 600 MW High Temperature Gas Cooled Reactor Gas Turbine (GTHTR300) system was fabricated and tested on its high temperature mechanical properties. The following results were derived. (1) High temperature static, fatigue and creep mode of fracture mainly occurred at ultra fine off-set fin made of SUS304. (2) Tested model showed almost the same high temperature strength, fatigue and creep behaviors of SUS304 as a main structural material at elevated temperature up to 873 K, (3) Recuperator designed for the GTHTR300 could be testified on the database of SUS304 base material and (4) The recuperator with the same fin plate structure could be practically applied to the GTHTR300. (author)

  12. Conjugate Heat transfer Analysis of helical fins with airfoil crosssection and its comparison with existing circular fin design for air cooled engines employing constant rectangular cross-section

    Ashwin Shridhar

    2015-06-01

    Full Text Available Air Cooled Engines have been used in a variety of applications, ranging from airplanes to motorbikes and even stationary or portable engines. Since modern automobiles and airplanes use engines delivering more power, they have to be cooled more efficiently due to which a more complex water cooling system is used for cooling engines with large displacements. Hence air cooling is becoming a thing of the past, especially in the aviation sector due to the advent of more efficient gas turbine engines. However air cooled internal combustion engines are still being used in a wide variety of two-wheelers ranging from small single cylinder engines to heavy duty liter class V-twins and Inline fours, due to the non-practicalities associated with the installment of a bulky water cooling system in two-wheelers. So one can ascertain that there is a scope for improving the efficiency of air cooled engines even further. The objective of this paper is to analyze currently existing fin design employed in most of the air cooled engines and improve it by changing the cross-section to a streamlined one and also making the fins in a helical orientation as opposed to the regular circular fins employed. Our analysis comprises of a computational fluid dynamics study of both the fin models with identical dimensions and simulated in the same environment using ANSYS FLUENT 15 software and we attempt to compare their performance using the temperature and heat transfer coefficient distribution plots obtained.

  13. Un modelo no hidrostático global con coordenada vertical basada en altura

    Simarro Grande, Juan Pablo

    2015-01-01

    Esta tesis documenta la investigación que he realizado en modelización atmosférica: se parte de las ecuaciones físicas de la atmósfera y se aplican métodos numéricos eficientes para encontrar una solución a dichas ecuaciones a partir de unas condiciones iniciales dadas. Para este fin, se ha desarrollado un modelo atmosférico cuyas características principales son: espectral en la representación horizontal de los campos, discretización vertical de alto orden de exactitud, y semi-implícito en la...

  14. Synthesis of Vertically Standing MoS2 Triangles on SiC.

    Lan, Feifei; Lai, Zhanping; Xu, Yongkuan; Cheng, Hongjuan; Wang, Zaien; Qi, Chengjun; Chen, Jianli; Zhang, Song

    2016-01-01

    Layered material MoS2 has been attracting much attention due to its excellent electronical properties and catalytic property. Here we report the synthesis of vertically standing MoS2 triangles on silicon carbon(SiC), through a rapid sulfidation process. Such edge-terminated films are metastable structures of MoS2, which may find applications in FinFETs and catalytic reactions. We have confirmed the catalytic property in a hydrogen evolution reaction(HER). The Tafel slope is about 54mV/decade. PMID:27550237

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

    Lim Sang-Seop

    2014-06-01

    Full Text Available 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 and hub cap for 6,000TEU container ships to improve the propulsion efficiency. The design parameters of PBCF have been selected based on the geometrical shape. Computational fluid dynamics (CFD analysis with a propeller open water (POW test was performed to check the validity of CFD analysis. The design of experiment (DOE case was selected as a full factorial design, and the experiment was analyzed by POW and CFD analysis. Analysis of variance (ANOVA was performed to determine the correlation among design parameters. Four design alternatives of PBCF were selected from the DOE. The shape of a propeller hub cap was selected as a divergent shape, and the divergent angle was determined by the DOE. Four design alternatives of PBCF were attached to the divergent hub cap, and the POW was estimated by CFD. As a result, the divergent hub cap with PBCF has a negative effect on the POW, which is induced by an increase in torque coefficient. A POW test and cavitation test were performed with a divergent hub cap with PBCF to verify the CFD result. The POW test result showed that the open water efficiency was increased approximately 2% with a divergent hub cap compared to a normal cap. The POW test result was similar to the CFD result, and the divergent hub cap with the PBCF models showed lower open water efficiency. This was attributed to an increase in the torque coefficient just like the CFD results. A cavitation test was performed using the 2 models selected. The test

  16. Vertical Wind Tunnel for Prediction of Rocket Flight Dynamics

    Hoani Bryson

    2016-03-01

    Full Text Available A customized vertical wind tunnel has been built by the University of Canterbury Rocketry group (UC Rocketry. This wind tunnel has been critical for the success of UC Rocketry as it allows the optimization of avionics and control systems before flight. This paper outlines the construction of the wind tunnel and includes an analysis of flow quality including swirl. A minimal modelling methodology for roll dynamics is developed that can extrapolate wind tunnel behavior at low wind speeds to much higher velocities encountered during flight. The models were shown to capture the roll flight dynamics in two rocket launches with mean roll angle errors varying from 0.26° to 1.5° across the flight data. The identified model parameters showed consistent and predictable variations over both wind tunnel tests and flight, including canard–fin interaction behavior. These results demonstrate that the vertical wind tunnel is an important tool for the modelling and control of sounding rockets.

  17. Performance and cost benefits analysis of double-pass solar collector with and without fins

    Highlights: • The thermal performances and cost analysis of the double-pass solar collector with and without fins absorber were discussed. • The theoretical and experimental study on the double-pass solar air collector with and without fins absorber was conducted. • The ratio of AC/AEG or the cost benefit ratio was presented. • The double-pass solar collector with fins absorber is more cost-effective compared to without fins absorber. - Abstract: The performance and cost benefit analysis of double-pass solar collector with and without fins have been conducted. The theoretical model using steady state analysis has been developed and compared with the experimental results. The performance curves of the double-pass solar collector with and without fins, which included the effects of mass flow rate and solar intensity on the thermal efficiency of the solar collector, were obtained. Results indicated that the thermal efficiency is proportional to the solar intensity at a specific mass flow rate. The thermal efficiency increased by 9% at a solar intensity of 425–790 W/m2 and mass flow rate of 0.09 kg/s. The theoretical and experimental analysis showed a similar trend as well as close agreement. Moreover, a cost-effectiveness model has been developed examine the cost benefit ratio of double-pass solar collector with and without fins. Evaluation of the annual cost (AC) and the annual energy gain (AEG) of the collector were also performed. The results show that the double-pass solar collector with fins is more cost-effective compared to the double-pass solar collector without fins for mass flow rate of 0.01–0.07 kg/s. Also, simulations were obtained for the double-pass solar collector with fins at Nusselt number of 5.42–36.21. The energy efficiency of collector increases with the increase of Nusselt number. The results show that by increasing the Nusselt number simultaneously would drop the outlet temperature at any solar intensity. Increase in Nusselt number

  18. High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas).

    Antunes, R; Kvadsheim, P H; Lam, F P A; Tyack, P L; Thomas, L; Wensveen, P J; Miller, P J O

    2014-06-15

    The potential effects of exposing marine mammals to military sonar is a current concern. Dose-response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1-2 kHz and 6-7 kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose-response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170 dB re 1 μPa, SELcum=173 dB re 1 μPa(2) s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose-response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources. PMID:24820645

  19. Heavy metals in tissues of stranded short-finned pilot whales

    Selected tissues from four short-finned pilot whales that stranded at Cumberland Island National Seashore were analyzed for total cadmium, mercury and selenium by neutron activation. Cadmium reached a maximum mean wet weight concentration of 31.4 ppm in the kidney tissues. Maximum mean wet weight concentrations of mercury, 230.9 ppm, and selenium, 44.2 ppm, were found in the liver tissues. The lowest concentration of each metal was found in the blubber. Postmortem examination showed that the whales had no food in their stomachs. The whales must have been utilizing metabolic reserves, contaminated with residual concentrations of heavy metals, prior to beaching. This utilization of reserves probably resulted in the high concentrations of cadmium, mercury and selenium found in the liver and kidney tissues. Since the heavy metal concentrations were three to four times greater in the stranded whales, as compared to apparently healthy whales of the same species, it is suggested that heavy metal toxicosis may have been a factor contributing to this particular stranding. (Auth.)

  20. 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

    2002-05-01

    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 exclusively with the pectoral fins at prolonged swimming speeds up to 3.2 total lengths per second (L s(-1); 30 min critical swimming speed, U(crit)). At higher speeds, gait transferred to a burst-and-coast BCF swimming mode that resulted in rapid fatigue. The triggerfish swam using undulations of the soft dorsal and anal fins up to 1.5 L s(-1), beyond which BCF undulations were recruited intermittently. BCF swimming was used continuously above 3.5 L s(-1), and was accompanied by synchronous undulations of the dorsal and anal fins. The triggerfish were capable of high, prolonged swimming speeds of up to 4.1 L s(-1) (30 min U(crit)). In both species, the rates of increase in oxygen consumption with swimming speed were higher during BCF swimming than during rigid-body MPF swimming. Our results indicate that, for these species, undulatory swimming is energetically more costly than rigid-body swimming, and therefore support the hypothesis that MPF swimming is more efficient. In addition, use of the BCF gait at higher swimming speed increased the cost of transport in both species beyond that predicted for MPF swimming at the same speeds. This suggests that, unlike for terrestrial locomotion, gait transition in fishes does not occur to reduce energetic costs, but to increase recruitable muscle mass and propulsive surfaces. The appropriate use of the power and exponential functions to model swimming energetics is also discussed. PMID:11948202

  1. Large filter feeding marine organisms as indicators of microplastic in the pelagic environment: the case studies of the Mediterranean basking shark (Cetorhinus maximus) and fin whale (Balaenoptera physalus).

    Fossi, Maria Cristina; Coppola, Daniele; Baini, Matteo; Giannetti, Matteo; Guerranti, Cristiana; Marsili, Letizia; Panti, Cristina; de Sabata, Eleonora; Clò, Simona

    2014-09-01

    The impact of microplastics (plastic fragments smaller than 5 mm) on large filter feeding marine organisms such as baleen whales and sharks are largely unknown. These species potentially are ingesting micro-litter by filter feeding activity. Here we present the case studies of the Mediterranean fin whale (Balaenoptera physalus) and basking shark (Cetorhinus maximus) exploring the toxicological effects of microplastics in these species measuring the levels of phthalates in both species. The results show higher concentration of MEHP in the muscle of basking shark in comparison to fin whale blubber. These species can be proposed as indicators of microplastics in the pelagic environment in the implementation of Descriptor 8 and 10 of the EU Marine Strategy Framework Directive (MSFD). PMID:24612776

  2. Vertical axis wind turbine airfoil

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  3. Fabrication and experiment of micro-pin-finned microchannels to study surface roughness effects on convective heat transfer

    Rectangular microchannels with three different micro-pin-finned spacings (2 μm, 4 μm and 8 μm) are fabricated using MEMS technique and the effect of the surface roughness on the convective heat transfer characteristics is examined under laminar flow conditions for 70 < Re < 250. The measured Poiseuille numbers (Po), defined as f Re as a measure of the friction, for the micro-pin-finned surfaces are lower than that for the smooth surface, which is attributed to the apparent slip associated with the flow separation and reattachment occurring in the regions between the pin-fins. Poiseuille number decreases with increasing pin-fin spacing because of its increased slip region. The measured Nusselt numbers, as a measure of the convective heat transfer enhancement, for the micro-pin-finned surfaces also decreases with increasing fin spacing, but Nu for 2 μm spacing is higher than that for the smooth surface and the Nusselt numbers for both 4- and 8 μm spacings are lower than the smooth surface case. Also, numerical predictions performed for the range of 2D pin fin spacings from 1 to 32 μm confirm that the competition between the heat transfer enhancement on the top surfaces of the fins and the heat transfer deterioration in the pin-fin spacing areas determines the overall heat transfer rate. The heat transfer on the top surfaces of the pin-fins tends to increase because of the locally developing flows both at the leading edge and the trailing edge of each fin. In contrast, the heat transfer in the pin-fin spacing areas decreases to the conduction level since the recirculation flows within the fin valleys are constricted by a suspended boundary. (paper)

  4. Autonomous vertical profiler data management

    Afzulpurkar, S.; Navelkar, G.S.; Desa, E.S.; Madhan, R.; Dabholkar, N.; Prabhudesai, S.P.; Mascarenhas, A.A.M.Q.

    and reduced data �� Ease in operation and one man deployable 2 Fig.1. Autonomous Vertical Profiler Table 1. Autonomous Vertical Profiler Specifications 2. Communication Communication with the AVP is through the satellite modem... Aluminum alloy, Acetal nose & tail cones Propulsion Single DC thruster Electronics 8051 and ARM7 microcontroller based Communication Radio modem (2.4 GHz) & Satellite Transmission (Iridium) GUI Labview based Energy Source Lithium Ion Polymer batteries...

  5. Early evolution of the lungfish pectoral fin endoskeleton: evidence from the Middle Devonian (Givetian Pentlandia macroptera

    ZerinaJohanson

    2014-08-01

    Full Text Available As the closest living relatives of tetrapods, lungfishes are frequently used as extant models for exploring the fin-to-limb transition. These studies have generally given little consideration to fossil taxa. This is because although lungfish fins are relatively common in the fossil record, the internal structure of these fins is virtually unknown. Information on pectoral-fin endoskeletons in fossil representatives of Dipnomorpha (the lungfish total group is limited to poorly preserved remains in the lungfish Dipterus and Conchopoma and more complete material in the porolepiform Glyptolepis. Here we describe a well-preserved pectoral-fin endoskeleton in the Middle Devonian (Givetian lungfish Pentlandia macroptera from the John O’Groats fish bed, Caithness, northeastern Scotland. The skeleton is in association with a cleithrum and clavicle, and consists of a series of at least eight mesomeres. Extensive series of preaxial and postaxial radials are present. Some of the radials are jointed, but none branch. No mesomere articulates with multiple radials on either its pre- or post-axial face. The first two mesomeres, corresponding to the humerus and ulna, bear well-developed axial processes. Uniquely among dipnomorphs, a distinct ossification centre corresponding to the radius is present in Pentlandia. A review of anatomy and development of the pectoral-fin endoskeleton in the living Neoceratodus is presented based on cleared and stained material representing different size stages. These developmental data, in conjunction with new details of primitive lungfish conditions based on Pentlandia, highlight many of the derived features of the pectoral-fin skeleton of Neoceratodus, and clarify patterns of appendage evolution within the dipnomorphs more generally.

  6. Kinematics of the ribbon fin in hovering and swimming of the electric ghost knifefish.

    Ruiz-Torres, Ricardo; Curet, Oscar M; Lauder, George V; Maciver, Malcolm A

    2013-03-01

    Weakly electric knifefish are exceptionally maneuverable swimmers. In prior work, we have shown that they are able to move their entire body omnidirectionally so that they can rapidly reach prey up to several centimeters away. Consequently, in addition to being a focus of efforts to understand the neural basis of sensory signal processing in vertebrates, knifefish are increasingly the subject of biomechanical analysis to understand the coupling of signal acquisition and biomechanics. Here, we focus on a key subset of the knifefish's omnidirectional mechanical abilities: hovering in place, and swimming forward at variable speed. Using high-speed video and a markerless motion capture system to capture fin position, we show that hovering is achieved by generating two traveling waves, one from the caudal edge of the fin and one from the rostral edge, moving toward each other. These two traveling waves overlap at a nodal point near the center of the fin, cancelling fore-aft propulsion. During forward swimming at low velocities, the caudal region of the fin continues to have counter-propagating waves, directly retarding forward movement. The gait transition from hovering to forward swimming is accompanied by a shift in the nodal point toward the caudal end of the fin. While frequency varies significantly to increase speed at low velocities, beyond approximately one body length per second, the frequency stays near 10 Hz, and amplitude modulation becomes more prominent. A coupled central pattern generator model is able to reproduce qualitative features of fin motion and suggest hypotheses regarding the fin's neural control. PMID:23197089

  7. Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily, Central Mediterranean Sea.

    Sciacca, Virginia; Caruso, Francesco; Beranzoli, Laura; Chierici, Francesco; De Domenico, Emilio; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Larosa, Giuseppina; Marinaro, Giuditta; Papale, Elena; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Simeone, Francesco; Viola, Salvatore; Riccobene, Giorgio

    2015-01-01

    In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, "NEMO-SN1", deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz-1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9-22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise. PMID:26581104

  8. Vertical external cavity surface emitting semiconductor lasers

    Holm, M

    2001-01-01

    Active stabilisation showed a relative locked linewidth of approx 3 kHz. Coarse tuning over 7 nm was achieved using a 3-plate birefingent filter plate while fine-tuning using cavity length change allowed tuning over 250 MHz. Vertical external cavity semiconductor lasers have emerged as an interesting technology based on current vertical cavity semiconductor laser knowledge. High power output into a single transverse mode has attracted companies requiring good fibre coupling for telecommunications systems. The structure comprises of a grown semiconductor Bragg reflector topped with a multiple quantum well gain region. This is then included in an external cavity. This device is then optically pumped to promote laser action. Theoretical modelling of AIGaAs based VECSEL structures was undertaken, showing the effect of device design on laser characteristics. A simple 3-mirror cavity was constructed to assess the static characteristics of the structure. Up to 153 mW of output power was achieved in a single transver...

  9. Fvm Analysis for Thermal and Hydraulic Behaviour of Circular Finned Mpfhs by Using Ag-H20 Nano

    Fluid Kuber Dwivedi

    2014-07-01

    Full Text Available In this exploration the influence of using two types of Nano fluids (Ag-water and Al203-water as a coolant at volumetric concentration is taken (c= 4% in micro pin fin heat sink with circular fins in addition to the un-finned micro-channel heat sink is deliberated with the help of commercially available computational fluid dynamics software Fluent 14. The evaluation of flow and heat transfer characteristics of MPFHS and cooling fluids has been made under the similar boundary condition; at the range of Reynolds number used is (100-500. The gotten outcomes is exemplified that, Ag-water Nano fluid is gives the minimum pressure drop and slightly maximum heat transfer rate compared to Al203-water Nano fluid. And circular finned heat sink is dissipating more amount of heat compared to un-finned micro-channel heat sink. But it is also gives the maximum pressure drop due to finned area.

  10. Structure and Output Characteristics of a TEM Array Fitted to a Fin Heat Exchanger

    Zhang, Z.; Chen, L. N.; Chen, Z. J.; Xiao, G. Q.; Liu, Z. J.

    2015-06-01

    In the design of a thermoelectric generator, both the heat transfer area and the number of thermoelectric modules (TEMs) should be increased accordingly as the generator power increases; crucially, both aspects need to be coordinated. A kilowatt thermoelectric generator with a fin heat exchanger is proposed for use in a constant-speed diesel generator unit. Interior fins enhance convective heat transfer, whereas an exterior fin segment increases the heat transfer area. The heat transfer surface is double that of a plane heat exchanger, and the temperature field over the exterior fins is constrained to a one-dimensional distribution. Between adjoining exterior fins, there is a cooling water channel with trapezoid cross-section, enabling compact TEMs and cooling them. Hence, more TEMs are built as a series-parallel array of TEMs with lower resistance and more stable output current. Under nonuniform conditions, to prevent circulation and energy loss, bypass diodes and antidiodes are added. Experiments and numerical calculations show that, with matching and optimization of the heat exchanger and TEM array, a stable maximum output power is obtainable from the interior of the thermoelectric generator system, which can be connected to an external maximum power point tracking system.

  11. Evolutionary multiobjective design of a flexible caudal fin for robotic fish.

    Clark, Anthony J; Tan, Xiaobo; McKinley, Philip K

    2015-12-01

    Robotic fish accomplish swimming by deforming their bodies or other fin-like appendages. As an emerging class of embedded computing system, robotic fish are anticipated to play an important role in environmental monitoring, inspection of underwater structures, tracking of hazardous wastes and oil spills, and the study of live fish behaviors. While integration of flexible materials (into the fins and/or body) holds the promise of improved swimming performance (in terms of both speed and maneuverability) for these robots, such components also introduce significant design challenges due to the complex material mechanics and hydrodynamic interactions. The problem is further exacerbated by the need for the robots to meet multiple objectives (e.g., both speed and energy efficiency). In this paper, we propose an evolutionary multiobjective optimization approach to the design and control of a robotic fish with a flexible caudal fin. Specifically, we use the NSGA-II algorithm to investigate morphological and control parameter values that optimize swimming speed and power usage. Several evolved fin designs are validated experimentally with a small robotic fish, where fins of different stiffness values and sizes are printed with a multi-material 3D printer. Experimental results confirm the effectiveness of the proposed design approach in balancing the two competing objectives. PMID:26601975

  12. A Novel Mini-DNA Barcoding Assay to Identify Processed Fins from Internationally Protected Shark Species

    Fields, Andrew T.; Abercrombie, Debra L.; Eng, Rowena; Feldheim, Kevin; Chapman, Demian D.

    2015-01-01

    There is a growing need to identify shark products in trade, in part due to the recent listing of five commercially important species on the Appendices of the Convention on International Trade in Endangered Species (CITES; porbeagle, Lamna nasus, oceanic whitetip, Carcharhinus longimanus scalloped hammerhead, Sphyrna lewini, smooth hammerhead, S. zygaena and great hammerhead S. mokarran) in addition to three species listed in the early part of this century (whale, Rhincodon typus, basking, Cetorhinus maximus, and white, Carcharodon carcharias). Shark fins are traded internationally to supply the Asian dried seafood market, in which they are used to make the luxury dish shark fin soup. Shark fins usually enter international trade with their skin still intact and can be identified using morphological characters or standard DNA-barcoding approaches. Once they reach Asia and are traded in this region the skin is removed and they are treated with chemicals that eliminate many key diagnostic characters and degrade their DNA (“processed fins”). Here, we present a validated mini-barcode assay based on partial sequences of the cytochrome oxidase I gene that can reliably identify the processed fins of seven of the eight CITES listed shark species. We also demonstrate that the assay can even frequently identify the species or genus of origin of shark fin soup (31 out of 50 samples). PMID:25646789

  13. Experimental study of heat transfer and pressures drops for cans with spiral herring-bone fins

    Cans fitted with herring-bone fins are used for cooling uranium in certain nuclear reactor. By herring-bone is meant a staggered arrangement of the fins which have a plane of symmetry parallel to the general direction of liquid flow. The main geometrical parameter are then: the number of fins, the number of herring-bones, the angle of inclination of the fins with respect to the can axis, the dimensions of the fins, the can diameter and the channel diameter. The research is essentially experimental. The test are of three types: full size tests, in conditions approaching those in the reactor (constant flux, CO2 under pressure); full size tests but with a constant wall temperature, much easier to set up, and intended to distinguish rapidly between the merits of the various types of can; large-scale tests with air at atmospheric pressure for studying the phenomena in more detail. For each can tried out there is a corresponding pressure drop coefficient, a mean thermal exchange coefficient Mo-bar and a minimum exchange coefficient Momin and Mo-bar are related by the expression Momin = Mo-bar * fc * f, where fc and f are respectively circumferential and longitudinal singularity factor determined from a statistical study of all the temperatures measured for each can. The results are presented in about thirty tables and figures the most noteworthy results being summarized in the conclusion. (authors)

  14. A flow separation study over a shortfin mako shark pectoral fin

    Bradshaw, Michael; Lang, Amy; Wahidi, Redha; Smith, Drew; Motta, Philip

    2011-11-01

    Many animals possess performance enhancing mechanisms, such as the denticles found on the skin of the shortfin mako shark (Isurus oxyrinchus). The shortfin mako, one of the fastest sharks on the planet, is covered by small, tooth-like scales that vary in bristling capability. Previous biological findings have shown that the scales increase in flexibility from the leading to trailing edge over the pectoral fin. As this fin is a primary control surface, the scale bristling may provide a mechanism for separation control that leads to decreased drag and increased maneuverability. Such findings can potentially lead to the development of similar micro-scale mechanisms to improve the efficiency of aerospace design. A left pectoral fin (71 cm span) was tested in a water tunnel facility under static and dynamic conditions. Digital Particle Image Velocimetry (DPIV) was used to characterize the flow over the fin. Various angles of attack at two speeds were tested (Re of 44,500 and 68,000). Two chord-wise locations, approximately mid-span where three-dimensional effects were minimized, were viewed to analyze the flow. After the initial testing, the fin was painted to eliminate the effect of the scales and retested to observe flow separation. Supported by REU SITE EEC grant number 1062611.

  15. The fin-to-limb transition as the re-organization of a Turing pattern.

    Onimaru, Koh; Marcon, Luciano; Musy, Marco; Tanaka, Mikiko; Sharpe, James

    2016-01-01

    A Turing mechanism implemented by BMP, SOX9 and WNT has been proposed to control mouse digit patterning. However, its generality and contribution to the morphological diversity of fins and limbs has not been explored. Here we provide evidence that the skeletal patterning of the catshark Scyliorhinus canicula pectoral fin is likely driven by a deeply conserved Bmp-Sox9-Wnt Turing network. In catshark fins, the distal nodular elements arise from a periodic spot pattern of Sox9 expression, in contrast to the stripe pattern in mouse digit patterning. However, our computer model shows that the Bmp-Sox9-Wnt network with altered spatial modulation can explain the Sox9 expression in catshark fins. Finally, experimental perturbation of Bmp or Wnt signalling in catshark embryos produces skeletal alterations which match in silico predictions. Together, our results suggest that the broad morphological diversity of the distal fin and limb elements arose from the spatial re-organization of a deeply conserved Turing mechanism. PMID:27211489

  16. The fin-to-limb transition as the re-organization of a Turing pattern

    Onimaru, Koh; Marcon, Luciano; Musy, Marco; Tanaka, Mikiko; Sharpe, James

    2016-01-01

    A Turing mechanism implemented by BMP, SOX9 and WNT has been proposed to control mouse digit patterning. However, its generality and contribution to the morphological diversity of fins and limbs has not been explored. Here we provide evidence that the skeletal patterning of the catshark Scyliorhinus canicula pectoral fin is likely driven by a deeply conserved Bmp–Sox9–Wnt Turing network. In catshark fins, the distal nodular elements arise from a periodic spot pattern of Sox9 expression, in contrast to the stripe pattern in mouse digit patterning. However, our computer model shows that the Bmp–Sox9–Wnt network with altered spatial modulation can explain the Sox9 expression in catshark fins. Finally, experimental perturbation of Bmp or Wnt signalling in catshark embryos produces skeletal alterations which match in silico predictions. Together, our results suggest that the broad morphological diversity of the distal fin and limb elements arose from the spatial re-organization of a deeply conserved Turing mechanism. PMID:27211489

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

    Sirović, Ana; Hildebrand, John A; Wiggins, Sean M

    2007-08-01

    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 multipath arrivals of their calls, was up to 56 km. The error in range measurements was 3.8 km using hyperbolic localization, and 3.4 km using multipath arrivals. Both species produced high-intensity calls; the average blue whale call source level was 189+/-3 dB re:1 microPa-1 m over 25-29 Hz, and the average fin whale call source level was 189+/-4 dB re:1 microPa-1 m over 15-28 Hz. Blue and fin whale populations in the Southern Ocean have remained at low numbers for decades since they became protected; using source level and detection range from passive acoustic recordings can help in calculating the relative density of calling whales. PMID:17672667

  18. Experimental Investigation of Innovative Internal Trailing Edge Cooling Configurations with Pentagonal Arrangement and Elliptic Pin Fin

    L. Tarchi

    2008-01-01

    Full Text Available This paper describes a heat transfer experimental study of four different internal trailing edge cooling configurations based on pin fin schemes. The aim of the study is the comparison between innovative configurations and standard ones. So, a circular pin fin configuration with an innovative pentagonal scheme is compared to a standard staggered scheme, while two elliptic pin fin configurations are compared to each other turning the ellipse from the streamwise to the spanwise direction. For each configuration, heat transfer and pressure loss measurements were made keeping the Mach number fixed at 0.3 and varying the Reynolds number from 9000 to 27000. In order to investigate the overall behavior of both endwall and pedestals, heat transfer measurements are performed using a combined transient technique. Over the endwall surface, the classic transient technique with thermochromic liquid crystals allows the measurement of a detailed heat transfer coefficient (HTC map. Pin fins are made of high thermal conductivity material, and an inverse data reduction method based on a finite element code allows to evaluate the mean HTC of each pin fin. Results show that the pentagonal arrangement generates a nonuniform HTC distribution over the endwall surface, while, in terms of average values, it is equivalent to the staggered configuration. On the contrary, the HTC map of the two elliptic configurations is similar, but the spanwise arrangement generates higher heat transfer coefficients and pressure losses.

  19. The Experimental Study of Atmospheric Stirling Engines Using Pin-Fin Arrays' Heat Exchangers

    Isshiki, Seita; Sato, Hidekazu; Konno, Shoji; Shiraishi, Hiroaki; Isshiki, Naotsugu; Fujii, Iwane; Mizui, Hiroyuki

    This paper reports experimental results on two kinds of atmospheric Stirling engines that were designed and manufactured using a pin-fin array heat exchanger for the heater and cooler (abbreviated to “pin-fin Stirling engine” hereafter). The first one is a large β type pin-fin Stirling engine with a 1.7-liter displacement volume and power piston volume. The heater consists of an aluminum circular disk with a diameter of 270mm and with large-scale pin-fin arrays carved into the surface. The maximum output reached 91W at a temperature difference of 330K, which is 36% of the scheduled value and 68% of the Kolin's cubic power law. The maximum thermal efficiency was estimated 4.2%. The second engine is an α type pin-fin Stirling engine. Glass syringes were used for the piston-cylinder system and the Ross-yoke mechanism was used for the crank mechanism. By changing temperature difference, the characteristic of output torque in the large range was measured with a precision torque detector.

  20. Turbulent Heat Transfer of a Finned Plate in a Duct as Tip Clearance Changes

    Fins are employed to enhance the cooling performance of a system. There are a number of studies relevant to geometry of fins. Meanwhile, the studies relevant to tip clearance, have not performed enough, which is the distance between the tips of the fins and the wall. We investigated the optimal tip clearance, which maximizes the heat transfers by experimental and numerical analyses with wider range of ReDh than the previous studies. Turbulent heat transfers of a finned plate were measured. For an extended range of tip clearance and ReDh than other studies. A joint experimental and numerical analyses was performed to measure heat transfers. Mass transfer experiments using electroplating system was used and FLUENT 6.3.26 was used for the calculation. For the narrow tip clearances below 5 mm, were investigated by numerical method only. The bypass flow to the tip clearance region contributes to heat transfer area at the tip clearance region and does not contributes that of the fin region. Thus, the optimal tip clearance was founded and it exists vicinity of 0.2 mm