Enhancement of the forced convective heat transfer on mini pin fin heat sinks with micro spiral fins

NASA Astrophysics Data System (ADS)

Khonsue, Osot

2018-02-01

This research is an experimental study on the characteristics of heat transfer and pressure drop in mini heat sinks using air as the working fluid. The experiments were performed under a constant heat flux ranging from 9.132-13.698 kW/m2 and the air Reynolds number range 322-1982. Three different types of mini heat sinks were rectangle pin fins, cylindrical pin fins, and spiral pin fins with 36x28x9 mm and 5 mm fins high. There were 63 fins altogether and all were made of aluminum. The results showed that the characteristics of the temperature of heat sink of spiral pin fins was the least. Meanwhile the average heat transfer coefficient and Nusselt number of spiral pin fins were the most . Regarding the pressure drop, the rectangular pin fins was the least. The results of this study can be used to guide the design and development of electronic devices cooling system with forced convective heat transfer for higher performance in the future.

Pleiotropic roles of Clostridium difficile sin locus

PubMed Central

Ou, Junjun; Dupuy, Bruno

2018-01-01

Clostridium difficile is the primary cause of nosocomial diarrhea and pseudomembranous colitis. It produces dormant spores, which serve as an infectious vehicle responsible for transmission of the disease and persistence of the organism in the environment. In Bacillus subtilis, the sin locus coding SinR (113 aa) and SinI (57 aa) is responsible for sporulation inhibition. In B. subtilis, SinR mainly acts as a repressor of its target genes to control sporulation, biofilm formation, and autolysis. SinI is an inhibitor of SinR, so their interaction determines whether SinR can inhibit its target gene expression. The C. difficile genome carries two sinR homologs in the operon that we named sinR and sinR’, coding for SinR (112 aa) and SinR’ (105 aa), respectively. In this study, we constructed and characterized sin locus mutants in two different C. difficile strains R20291 and JIR8094, to decipher the locus’s role in C. difficile physiology. Transcriptome analysis of the sinRR’ mutants revealed their pleiotropic roles in controlling several pathways including sporulation, toxin production, and motility in C. difficile. Through various genetic and biochemical experiments, we have shown that SinR can regulate transcription of key regulators in these pathways, which includes sigD, spo0A, and codY. We have found that SinR’ acts as an antagonist to SinR by blocking its repressor activity. Using a hamster model, we have also demonstrated that the sin locus is needed for successful C. difficile infection. This study reveals the sin locus as a central link that connects the gene regulatory networks of sporulation, toxin production, and motility; three key pathways that are important for C. difficile pathogenesis. PMID:29529083

Experimental Investigation on Effect of Fin Shape on the Thermal-Hydraulic Performance of Compact Fin-and-Tube Heat Exchangers

NASA Astrophysics Data System (ADS)

Moorthy, P.; Oumer, A. N.; Ishak, M.

2018-03-01

The aim of this paper is to investigate the effect of fin shapes on the performance of compact finned flat tube heat exchangers. Three types of fin shapes namely plain, wavy, and rectangular grooved fins attached to three by three arrays of flat tube banks were considered. Moreover, the tubes were deployed in in-line and staggered arrangements. In addition to the fin shapes, the air velocity and the tube inclination angles were varied and the thermal-hydraulic performance was analysed. On the other hand, the temperatures at the tube surfaces were kept constant to produce constant heat flux throughout the study. The results showed that as flowrate increases, the heat transfer increases, however, the friction factor decreases. Staggered arrangement produces higher heat transfer and friction factor than inline fin. Moreover, the rectangular fin is the best in terms of high heat transfer however the drawback of high friction factor leads the fin to have the least efficiency of all. On the other hand, plain fin had the least heat transfer performance however the highest efficiency was achieved. Therefore, plain fin should be used when efficiency is prioritized and rectangular fin when high heat transfer is desired.

Curvature-induced stiffening of a fish fin.

PubMed

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

2017-05-01

How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the membrane underlies the increase in stiffness. Using three-dimensional reconstruction of a mackerel ( Scomber japonicus ) pectoral fin for illustration, we calculate the range of stiffnesses this fin is expected to span by changing curvature. The three-dimensional reconstruction shows that, even in its geometrically flat state, a functional curvature is embedded within the fin microstructure owing to the morphology of individual rays. As the ability of a propulsive surface to transmit force to the surrounding fluid is limited by its stiffness, the fin curvature controls the coupling between the fish and its surrounding fluid. Thereby, our results provide mechanical underpinnings and morphological predictions for the hypothesis that the spanned range of fin stiffnesses correlates with the behaviour and the ecological niche of the fish. © 2017 The Author(s).

Curvature-induced stiffening of a fish fin

PubMed Central

2017-01-01

How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the membrane underlies the increase in stiffness. Using three-dimensional reconstruction of a mackerel (Scomber japonicus) pectoral fin for illustration, we calculate the range of stiffnesses this fin is expected to span by changing curvature. The three-dimensional reconstruction shows that, even in its geometrically flat state, a functional curvature is embedded within the fin microstructure owing to the morphology of individual rays. As the ability of a propulsive surface to transmit force to the surrounding fluid is limited by its stiffness, the fin curvature controls the coupling between the fish and its surrounding fluid. Thereby, our results provide mechanical underpinnings and morphological predictions for the hypothesis that the spanned range of fin stiffnesses correlates with the behaviour and the ecological niche of the fish. PMID:28566508

Fin development in stream- and hatchery-reared Atlantic salmon

USGS Publications Warehouse

Pelis, Ryan M.; McCormick, S.D.

2003-01-01

To determine the effect of development and environment on fin growth, we measured fin lengths of juvenile Atlantic salmon (Salmo salar) from two hatcheries (August, October and April-May), stream-reared fish (July and October) stocked as fry into two tributaries, and smelts from the main stem of the Connecticut River (May). For stream-reared parr, there was a linear relationship between the dorsal, caudal and anal fins with fork length, while the pectoral, pelvic and adipose fins exhibited a curvilinear relationship with fork length. Parr from a high gradient stream had larger caudal fins than fish from a low gradient stream, but other fins did not differ. Regression lines for the fins of stream-reared smelts were all linear when fin length was regressed against fork length. Stream-reared parr had larger pectoral, pelvic and anal fins than smolts of similar size while dorsal and caudal fin lengths did not differ. Regression equations formulated using the fins of stream-reared parr were used to calculate the percent difference (100 x observed fin length/expected) in fin lengths between stream- and hatchery-reared parr. The pelvic, adipose, caudal and anal fins of hatchery-reared parr showed no signs of degeneration by the first sampling period 7 months after hatching, whereas degeneration in the pectoral (13-20%) and dorsal (15-18%) fins was evident at this time. By the end of the study, degeneration was present in every fin except the adipose, with the pectoral (35-65%) and dorsal (32-58%) fins exhibiting the greatest amount of fin loss. All fins of hatchery-reared parr became shorter with time. There were minor differences in fin degeneration among parr from the two hatcheries, but the overall pattern of decreasing fin size was similar, indicating a common cause of fin degeneration. Comparison of stream- and hatchery-reared fish is a valuable means of determining the impact of captive environments on fin growth.

Heat exchanger with transpired, highly porous fins

DOEpatents

Kutscher, Charles F.; Gawlik, Keith

2002-01-01

The heat exchanger includes a fin and tube assembly with increased heat transfer surface area positioned within a hollow chamber of a housing to provide effective heat transfer between a gas flowing within the hollow chamber and a fluid flowing in the fin and tube assembly. A fan is included to force a gas, such as air, to flow through the hollow chamber and through the fin and tube assembly. The fin and tube assembly comprises fluid conduits to direct the fluid through the heat exchanger, to prevent mixing with the gas, and to provide a heat transfer surface or pathway between the fluid and the gas. A heat transfer element is provided in the fin and tube assembly to provide extended heat transfer surfaces for the fluid conduits. The heat transfer element is corrugated to form fins between alternating ridges and grooves that define flow channels for directing the gas flow. The fins are fabricated from a thin, heat conductive material containing numerous orifices or pores for transpiring the gas out of the flow channel. The grooves are closed or only partially open so that all or substantially all of the gas is transpired through the fins so that heat is exchanged on the front and back surfaces of the fins and also within the interior of the orifices, thereby significantly increasing the available the heat transfer surface of the heat exchanger. The transpired fins also increase heat transfer effectiveness of the heat exchanger by increasing the heat transfer coefficient by disrupting boundary layer development on the fins and by establishing other beneficial gas flow patterns, all at desirable pressure drops.

Numerical studies on heat transfer and pressure drop characteristics of flat finned tube bundles with various fin materials

NASA Astrophysics Data System (ADS)

Peng, Y.; Zhang, S. J.; Shen, F.; Wang, X. B.; Yang, X. R.; Yang, L. J.

2017-11-01

The air-cooled heat exchanger plays an important role in the field of industry like for example in thermal power plants. On the other hand, it can be used to remove core decay heat out of containment passively in case of a severe accident circumstance. Thus, research on the performance of fins in air-cooled heat exchangers can benefit the optimal design and operation of cooling systems in nuclear power plants. In this study, a CFD (Computational Fluid Dynamic) method is implemented to investigate the effects of inlet velocity, fin spacing and tube pitch on the flow and the heat transfer characteristics of flat fins constructed of various materials (316L stainless steel, copper-nickel alloy and aluminium). A three dimensional geometric model of flat finned tube bundles with fixed longitudinal tube pitch and transverse tube pitch is established. Results for the variation of the average convective heat transfer coefficient with respect to cooling air inlet velocity, fin spacing, tube pitch and fin material are obtained, as well as for the pressure drop of the cooling air passing through finned tube. It is shown that the increase of cooling air inlet velocity results in enhanced average convective heat transfer coefficient and decreasing pressure drop. Both fin spacing and tube pitch engender positive effects on pressure drop and have negative effects on heat transfer characteristics. Concerning the fin material, the heat transfer performance of copper-nickel alloy is superior to 316L stainless steel and inferior to aluminium.

Embryonic development of fin spines in Callorhinchus milii (Holocephali); implications for chondrichthyan fin spine evolution.

PubMed

Jerve, Anna; Johanson, Zerina; Ahlberg, Per; Boisvert, Catherine

2014-01-01

Fin spines are commonly known from fossil gnathostomes (jawed vertebrates) and are usually associated with paired and unpaired fins. They are less common among extant gnathostomes, being restricted to the median fins of certain chondrichthyans (cartilaginous fish), including chimaerids (elephant sharks) and neoselachians (sharks, skates, and rays). Fin spine growth is of great interest and relevance but few studies have considered their evolution and development. We investigated the development of the fin spine of the chimaerid Callorhinchus milii using stained histological sections from a series of larval, hatchling, and adult individuals. The lamellar trunk dentine of the Callorhinchus spine first condenses within the mesenchyme, rather than at the contact surface between mesenchyme and epithelium, in a manner more comparable to dermal bone formation than to normal odontode development. Trabecular dentine forms a small component of the spine under the keel; it is covered externally with a thin layer of lamellar trunk dentine, which is difficult to distinguish in sectioned adult spines. We suggest that the distinctive characteristics of the trunk dentine may reflect an origin through co-option of developmental processes involved in dermal bone formation. Comparison with extant Squalus and a range of fossil chondrichthyans shows that Callorhinchus is more representative than Squalus of generalized chondrichthyan fin-spine architecture, highlighting its value as a developmental model organism. © 2014 Wiley Periodicals, Inc.

Investigation of internally finned LED heat sinks

NASA Astrophysics Data System (ADS)

Li, Bin; Xiong, Lun; Lai, Chuan; Tang, Yumei

2018-03-01

A novel heat sink is proposed, which is composed of a perforated cylinder and internally arranged fins. Numerical studies are performed on the natural convection heat transfer from internally finned heat sinks; experimental studies are carried out to validate the numerical results. To compare the thermal performances of internally finned heat sinks and externally finned heat sinks, the effects of the overall diameter, overall height, and installation direction on maximum temperature, air flow and heat transfer coefficient are investigated. The results demonstrate that internally finned heat sinks show better thermal performance than externally finned heat sinks; the maximum temperature of internally finned heat sinks decreases by up to 20% compared with the externally finned heat sinks. The existence of a perforated cylinder and the installation direction of the heat sink affect the thermal performance significantly; it is shown that the heat transfer coefficient of the heat sink with the perforated cylinder is improved greater than that with the imperforated cylinder by up to 34%, while reducing the mass of the heat sink by up to 13%. Project supported by the Scientific Research Fund of Sichuan Provincial Education Department (No. 18ZB0516) and the Sichuan University of Arts and Science (No. 2016KZ009Y).

Role of Pectoral Fin Flexibility in Robotic Fish Performance

NASA Astrophysics Data System (ADS)

Bazaz Behbahani, Sanaz; Tan, Xiaobo

2017-08-01

Pectoral fins play a vital role in the maneuvering and locomotion of fish, and they have become an important actuation mechanism for robotic fish. In this paper, we explore the effect of flexibility of robotic fish pectoral fins on the robot locomotion performance and mechanical efficiency. A dynamic model for the robotic fish is presented, where the flexible fin is modeled as multiple rigid elements connected via torsional springs and dampers. Blade element theory is used to capture the hydrodynamic force on the fin. The model is validated with experimental results obtained on a robotic fish prototype, equipped with 3D-printed fins of different flexibility. The model is then used to analyze the impacts of fin flexibility and power/recovery stroke speed ratio on the robot swimming speed and mechanical efficiency. It is found that, in general, flexible fins demonstrate advantages over rigid fins in speed and efficiency at relatively low fin-beat frequencies, while rigid fins outperform flexible fins at higher frequencies. For a given fin flexibility, the optimal frequency for speed performance differs from the optimal frequency for mechanical efficiency. In addition, for any given fin, there is an optimal power/recovery stroke speed ratio, typically in the range of 2-3, that maximizes the speed performance. Overall, the presented model offers a promising tool for fin flexibility and gait design, to achieve speed and efficiency objectives for robotic fish actuated with pectoral fins.

IN GRAMMAR'S FALL, WE SINNED ALL.

ERIC Educational Resources Information Center

TIBBETTS, A.M.

THROUGH THEIR LOSS OF FAITH IN TRADITIONAL GRAMMAR, MEN HAVE "SINNED" AND CONTRIBUTED SLIGHTLY BUT IMPORTANTLY TO THE CREATION OF AN AMORAL AND RELATIVISTIC SOCIETY. PROMPTED BY THE SIN OF INTELLECTUAL PRIDE, SOME LINGUISTS SEEM TO ASSUME THAT GRAMMATICAL PROBLEMS CAN BE SOLVED BY RATIOCINATION ALONE. IGNORANCE OF THE PAST--ANOTHER SIN--AND…

Fin-line horn antenna

DOEpatents

Reindel, John

1990-01-01

A fin line circuit card containing a fin line slot feeds a dipole antenna ich extends a quarterwave outside the waveguide and provides an energy beam focal point at or near the open end of the waveguide. The dipole antenna thus maintains a wide and nearly constant beamwidth, low VSWR and a circular symmetric radiation pattern for use in electronic warfare direction finding and surveillance applications.

The Fifth International Ice Nucleation Workshop Activities FIN-1 and FIN-2: Overview and Selected Results

NASA Astrophysics Data System (ADS)

Moehler, O.; Cziczo, D. J.; DeMott, P. J.; Hiranuma, N.; Petters, M. D.

2015-12-01

The role of aerosol particles for ice formation in clouds is one of the largest uncertainties in understanding the Earth's weather and climate systems, which is related to the poor knowledge of ice nucleation microphysics or of the nature and atmospheric abundance of ice nucleating particles (INPs). During the recent years, new mobile instruments were developed for measuring the concentration, size and chemical composition of INPs, which were tested during the three-part Fifth International Ice Nucleation (FIN) workshop. The FIN activities addressed not only instrument issues, but also important science topics like the nature of atmospheric INP and cloud ice residuals, the ice nucleation activity of relevant atmospheric aerosols, or the parameterization of ice formation in atmospheric weather and climate models. The first activity FIN-1 was conducted during November 2014 at the AIDA cloud chamber. It involved co-locating nine single particle mass spectrometers to evaluate how well they resolve the INP and ice residual composition and how spectra from different instruments compare for relevant atmospheric aerosols. We conducted about 90 experiments with mineral, carbonaceous and biological aerosol types, some also coated with organic and inorganic compounds. The second activity FIN-2 was conducted during March 2015 at the AIDA facility. A total of nine mobile INP instruments directly sampled from the AIDA aerosol chambers. Wet suspension and filter samples were also taken for offline INP processing. A refereed blind intercomparison was conducted during two days of the FIN-2 activity. The third activity FIN-3 will take place at the Desert Research Institute's Storm Peak Laboratory (SPL) in order to test the instruments' performance in the field. This contribution will introduce the FIN activities, summarize first results from the formal part of FIN-2, and discuss selected results, mainly from FIN-1 for the effect of coating on the ice nucleation (IN) by mineral

An experimental study of PCM based finned and un-finned heat sinks for passive cooling of electronics

NASA Astrophysics Data System (ADS)

Usman, Hazrat; Ali, Hafiz Muhammad; Arshad, Adeel; Ashraf, Muhammad Junaid; Khushnood, Shahab; Janjua, Muhammad Mansoor; Kazi, S. N.

2018-05-01

This experimental study determines and compares the thermal performance of unfinned and finned PCM based heat sinks. For the analysis considering pin-fins as thermal conductivity enhancer (TCE), triangular configuration is considered. It is further classified into inline and staggered pin-fin arrangements. Three popular variants of paraffin namely paraffin wax, RT-44 and RT-35HC are incorporated as phase change materials (PCMs) inside the heat sink. The volume fraction of pin-fins and PCMs are kept constant at 9% and 90% respectively. The heat input at the base of heat sinks ranges from 5 W to 8 W. The results are presented in two different cases, charging and discharging, and the analysis of temperature variation and comparison of fin arrangements in three different heat sinks with and without PCM. Further the enhancement ratios are determined to quantify the thermal performance in operation time of heat sink for passive cooling with the influence of PCMs and TCEs. The results suggest triangular inline pin-fin as the dominant heat sink geometry and RT-44 as the most efficient PCM for passive thermal management of electronic devices.

Gate length scaling optimization of FinFETs

NASA Astrophysics Data System (ADS)

Chen, Shoumian; Shang, Enming; Hu, Shaojian

2018-06-01

This paper introduces a device performance optimization approach for the FinFET through optimization of the gate length. As a result of reducing the gate length, the leakage current (Ioff) increases, and consequently, the stress along the channel enhances which leads to an increase in the drive current (Isat) of the PMOS. In order to sustain Ioff, work function is adjusted to offset the effect of the increased stress. Changing the gate length of the transistor yields different drive currents when the leakage current is fixed by adjusting the work function. For a given device, an optimal gate length is found to provide the highest drive current. As an example, for a standard performance device with Ioff = 1 nA/um, the best performance Isat = 856 uA/um is at L = 34 nm for 14 nm FinFET and Isat = 1130 uA/um at L = 21 nm for 7 nm FinFET. A 7 nm FinFET will exhibit performance boost of 32% comparing with 14 nm FinFET. However, applying the same method to a 5 nm FinFET, the performance boosting is out of expectance comparing to the 7 nm FinFET, which is due to the severe short-channel-effect and the exhausted channel stress in the FinFET.

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

NASA Astrophysics Data System (ADS)

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.

14 CFR 23.445 - Outboard fins or winglets.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Outboard fins or winglets. 23.445 Section... § 23.445 Outboard fins or winglets. (a) If outboard fins or winglets are included on the horizontal... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces or...

14 CFR 23.445 - Outboard fins or winglets.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Outboard fins or winglets. 23.445 Section... § 23.445 Outboard fins or winglets. (a) If outboard fins or winglets are included on the horizontal... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces or...

14 CFR 23.445 - Outboard fins or winglets.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Outboard fins or winglets. 23.445 Section... § 23.445 Outboard fins or winglets. (a) If outboard fins or winglets are included on the horizontal... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces or...

A biorobotic pectoral fin for autonomous undersea vehicles.

PubMed

Tangorra, James L; Davidson, S Naomi; Madden, Peter G; Lauder, George V; Hunter, Ian W

2006-01-01

A biorobotic fin for autonomous undersea vehicles (AUVs) was developed based on studies of the anatomy, kinematics, and hydrodynamics of the bluegill sunfish pectoral fin. The biorobotic fin was able to produce many of the complex fin motions used by the sunfish during steady swimming and was used to investigate mechanisms of thrust production and control. This biorobotic fin is an excellent experimental tool and is an important first step towards developing propulsive devices that give AUVs maneuvering characteristics that match and exceed those of highly maneuverable fish.

How fish swim: flexible fin thrusters as an EAP platform

NASA Astrophysics Data System (ADS)

Lauder, George V.

2007-04-01

Fish are capable of remarkable locomotor performance and use their fins extensively for both propulsion and maneuvering. Recent interest in using fishes as inspiration for the design of a new generation of autonomous underwater vehicles has prompted both new experimental studies of fish locomotor function and efforts to use electroactive polymers (EAP) as actuators in fish-inspired propulsive devices. The fins of fishes allow precise control over body position and vectoring of thrust during propulsion and maneuvering. Recent experimental studies of fish locomotion have revealed that fins exhibit much greater flexibility than previously suspected and that there is considerable deformation of the fin surface during locomotion. The fins of the large group known as ray-finned fishes are supported by fin rays, which have a bilaminar structure that allows active curvature control of the ray and fin surface by the fin musculature. Fish have up to seven different fins, and these fins may interact with each other hydrodynamically during locomotion. Fish fins provide an excellent test platform for the use of electroactive polymer actuators as the frequency of movement is typically less than 5 Hz, and fin muscle strains typically range from 2 to 10%. Recent developments of biorobotic fish pectoral fins actuated with EAP are reviewed.

Kinematics of ribbon-fin locomotion in the bowfin, Amia calva.

PubMed

Jagnandan, Kevin; Sanford, Christopher P

2013-12-01

An elongated dorsal and/or anal ribbon-fin to produce forward and backward propulsion has independently evolved in several groups of fishes. In these fishes, fin ray movements along the fin generate a series of waves that drive propulsion. There are no published data on the use of the dorsal ribbon-fin in the basal freshwater bowfin, Amia calva. In this study, frequency, amplitude, wavelength, and wave speed along the fin were measured in Amia swimming at different speeds (up to 1.0 body length/sec) to understand how the ribbon-fin generates propulsion. These wave properties were analyzed to (1) determine whether regional specialization occurs along the ribbon-fin, and (2) to reveal how the undulatory waves are used to control swimming speed. Wave properties were also compared between swimming with sole use of the ribbon-fin, and swimming with simultaneous use of the ribbon and pectoral fins. Statistical analysis of ribbon-fin kinematics revealed no differences in kinematic patterns along the ribbon-fin, and that forward propulsive speed in Amia is controlled by the frequency of the wave in the ribbon-fin, irrespective of the contribution of the pectoral fin. This study is the first kinematic analysis of the ribbon-fin in a basal fish and the model species for Amiiform locomotion, providing a basis for understanding ribbon-fin locomotion among a broad range of teleosts. © 2013 Wiley Periodicals, Inc.

Grid Fin Stabilization of the Orion Launch Abort Vehicle

NASA Technical Reports Server (NTRS)

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

Evaluation of fins used in underwater swimming.

PubMed

Pendergast, D R; Mollendorf, J; Logue, C; Samimy, S

2003-01-01

Underwater swimmers use fins which augment thrust to overcome drag and propel the diver. The VdotO2 of swimming as a function of speed, velocity as a function of kick frequency, maximal speed (v), maximal oxygen consumption (VdotO2) and the maximal thrust were determined for eight fins in 10 male divers swimming at 1.25 m depth in a 60 m annular pool. A theoretical analysis of fin cycles was also performed. VdotO2 increased as a second order polynomial as a function of velocity; VdotO2 = 0.045 + 1.65B V + 1.66 (2) V2 (r2 = 0.997), VdotO2 = 0.25 + 1.03 V + 1.83 V2 (r2 = 0.997) and VdotO2 = -0.15 + 2.26 V + 1.49 V2 (r2 = 0.997), for least, average and most economical fins respectively. Kick frequency increased linearly with velocity and had a unique movement path (signature), giving theoretical values that agreed with the measured thrust, drag and efficiency. In conclusion, virtually all thrust comes from the downward power stroke, with rigid fins kicked deep (high drag), while flexible fins are kicked less deep but with higher frequency (low efficiency). Kick depth and frequency explain the performance of the eight tested fins, and should be optimized to enhance diver performance.

Undulating fins produce off-axis thrust and flow structures.

PubMed

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.

Aerothermoelastic Analysis of a NASP-Like Vertical Fin

NASA Technical Reports Server (NTRS)

Rodgers, John P.

1992-01-01

Several aeroelastic stability analyses for a vertical fin similar to that of the National Aero-Space Plane are described. The objectives of the study were to design and obtain an experimental data base for a supersonic wind-tunnel model of the fin in order to examine the effects of thermal loading on the flutter characteristics. This paper describes the preliminary efforts to design the wind-tunnel model, including several of the geometric parameter variations that were analyzed. The dominant flutter mechanism involved a flap vibration mode and a fin bending mode. Variation of the thicknesses of flap and root flexures, used to attach the flap to the fin, and the fin to a support, significantly affected the flutter boundary. Uniform thermal loads, affecting only material properties, had little effect, as did the application of different uniform temperatures to each side of the fin. In contrast, the application of significant chord-wise thermal gradients induced stresses which reduced the flutter dynamic pressure by as much as 37 percent. For less extreme distributed loading, the low-aspect ratio fin was relatively unaffected.

Performance enhancement of fin attached ice-on-coil type thermal storage tank for different fin orientations using constrained and unconstrained simulations

NASA Astrophysics Data System (ADS)

Kim, M. H.; Duong, X. Q.; Chung, J. D.

2017-03-01

One of the drawbacks in latent thermal energy storage system is the slow charging and discharging time due to the low thermal conductivity of the phase change materials (PCM). This study numerically investigated the PCM melting process inside a finned tube to determine enhanced heat transfer performance. The influences of fin length and fin numbers were investigated. Also, two different fin orientations, a vertical and horizontal type, were examined, using two different simulation methods, constrained and unconstrained. The unconstrained simulation, which considers the density difference between the solid and liquid PCM showed approximately 40 % faster melting rate than that of constrained simulation. For a precise estimation of discharging performance, unconstrained simulation is essential. Thermal instability was found in the liquid layer below the solid PCM, which is contrary to the linear stability theory, due to the strong convection driven by heat flux from the coil wall. As the fin length increases, the area affected by the fin becomes larger, thus the discharging time becomes shorter. The discharging performance also increased as the fin number increased, but the enhancement of discharging performance by more than two fins was not discernible. The horizontal type shortened the complete melting time by approximately 10 % compared to the vertical type.

Honeycomb-Fin Heat Sink

NASA Technical Reports Server (NTRS)

Rippel, Wally E.

1989-01-01

Improved finned heat sink for electronic components more lightweight, inexpensive, and efficient. Designed for use with forced air, easily scaled up to dissipate power up to few hundred watts. Fins are internal walls of aluminum honeycomb structure. Cell structure gives strength to thin aluminum foil. Length of channels chosen for thermodynamic efficency; columns of cells combined in any reasonable number because flowing air distributed to all. Heat sink cools nearly as effectively at ends as near its center, no matter how many columns of cells combined.

Molecular mechanisms underlying the exceptional adaptations of batoid fins.

PubMed

Nakamura, Tetsuya; Klomp, Jeff; Pieretti, Joyce; Schneider, Igor; Gehrke, Andrew R; Shubin, Neil H

2015-12-29

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)-Fibroblast growth factor (Fgf)-Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies.

Molecular mechanisms underlying the exceptional adaptations of batoid fins

PubMed Central

Nakamura, Tetsuya; Klomp, Jeff; Pieretti, Joyce; Schneider, Igor; Gehrke, Andrew R.; Shubin, Neil H.

2015-01-01

Extreme novelties in the shape and size of paired fins are exemplified by extinct and extant cartilaginous and bony fishes. Pectoral fins of skates and rays, such as the little skate (Batoid, Leucoraja erinacea), show a strikingly unique morphology where the pectoral fin extends anteriorly to ultimately fuse with the head. This results in a morphology that essentially surrounds the body and is associated with the evolution of novel swimming mechanisms in the group. In an approach that extends from RNA sequencing to in situ hybridization to functional assays, we show that anterior and posterior portions of the pectoral fin have different genetic underpinnings: canonical genes of appendage development control posterior fin development via an apical ectodermal ridge (AER), whereas an alternative Homeobox (Hox)–Fibroblast growth factor (Fgf)–Wingless type MMTV integration site family (Wnt) genetic module in the anterior region creates an AER-like structure that drives anterior fin expansion. Finally, we show that GLI family zinc finger 3 (Gli3), which is an anterior repressor of tetrapod digits, is expressed in the posterior half of the pectoral fin of skate, shark, and zebrafish but in the anterior side of the pelvic fin. Taken together, these data point to both highly derived and deeply ancestral patterns of gene expression in skate pectoral fins, shedding light on the molecular mechanisms behind the evolution of novel fin morphologies. PMID:26644578

Heat Transfer Measurements of Internally Finned Rotating Heat Pipes.

DTIC Science & Technology

1983-12-01

42 C. RESULTS OF STRAIGHT 22 FIN CONDENSER o . o . 51 D. RESULTS OF HELICAL 14 AND 16 FIN CONDENSER o 51 E. RESULTS OF HELICAL 36 FIN...88 C.6 RESULTS OF STRAIGHT 22 FIN CONDENSER AT 2800 RPM . . . . . . . . . . . . . . . . . . . . 89 C.7 RESULTS OF HELICAL 16 FIN CONDENSER ...AT 700 RPM . 90 C.8 RESULTS OF HELICAL 16 PIN CONDENSER AT 1600 RPM . 91 C.9 RESULTS OF HELICAL 16 PIN CONDENSER AT 2800 RPM . 92 C. 10 RESULTS OF

Flow structure of natural dehumidification over a horizontal finned-tube

NASA Astrophysics Data System (ADS)

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.

Expression of the SIN3 homologue from banana, MaSIN3, suppresses ABA responses globally during plant growth in Arabidopsis.

PubMed

Luxmi, Raj; Garg, Rashmi; Srivastava, Sudhakar; Sane, Aniruddha P

2017-11-01

The SIN3 family of co-repressors is a family of highly conserved eukaryotic repressor proteins that regulates diverse functions in yeasts and animals but remains largely uncharacterized functionally even in plants like Arabidopsis. The sole SIN3 homologue in banana, MaSIN3, was identified as a 1408 amino acids, nuclear localized protein conserved to other SIN3s in the PAH, HID and HCR domains. Interestingly, MaSIN3 over-expression in Arabidopsis mimics a state of reduced ABA responses throughout plant development affecting growth processes such as germination, root growth, stomatal closure and water loss, flowering and senescence. The reduction in ABA responses is not due to reduced ABA levels but due to suppression of expression of several transcription factors mediating ABA responses. Transcript levels of negative regulators of germination (ABI3, ABI5, PIL5, RGL2 and RGL3) are reduced post-imbibition while those responsible for GA biosynthesis are up-regulated in transgenic MaSIN3 over-expressers. ABA-associated transcription factors are also down-regulated in response to ABA treatment. The HDAC inhibitors, SAHA and sodium butyrate, in combination with ABA differentially suppress germination in control and transgenic lines suggesting the recruitment by MaSIN3 of HDACs involved in suppression of ABA responses in different processes. The studies provide an insight into the ability of MaSIN3 to specifically affect a subset of developmental processes governed largely by ABA. Copyright © 2017 Elsevier B.V. All rights reserved.

The origin of a new fin skeleton through tinkering

PubMed Central

Stewart, Thomas A.

2015-01-01

Adipose fins are positioned between the dorsal and caudal fins of many teleost fishes and primitively lack skeleton. In at least four lineages, adipose fins have evolved lepidotrichia (bony fin rays), co-opting the developmental programme for the dermal skeleton of other fins into this new territory. Here I provide, to my knowledge, the first description of lepidotrichia development in an adipose fin, characterizing the ontogeny of the redtail catfish, Phractocephalus hemioliopterus. Development of these fin rays differs from canonical lepidotrich development in the following four ways: skeleton begins developing in adults, not in larvae; rays begin developing at the fin's distal tip, not proximally; the order in which rays ossify is variable, not fixed; and lepidotrichia appear to grow both proximally and distally, not exclusively proximodistally. Lepidotrichia are often wavy, of irregular thickness and exhibit no regular pattern of segmentation or branching. This skeleton is among the most variable observed in a vertebrate appendage, offering a unique opportunity to explore the basis of hypervariation, which is generally assumed to reflect an absence of function. I argue that this variation reflects a lack of canalization as compared with other, more ancient lepidotrichs and suggest developmental context can affect the morphology of serial homologues. PMID:26179803

Sin3b interacts with Myc and decreases Myc levels.

PubMed

Garcia-Sanz, Pablo; Quintanilla, Andrea; Lafita, M Carmen; Moreno-Bueno, Gema; García-Gutierrez, Lucia; Tabor, Vedrana; Varela, Ignacio; Shiio, Yuzuru; Larsson, Lars-Gunnar; Portillo, Francisco; Leon, Javier

2014-08-08

Myc expression is deregulated in many human cancers. A yeast two-hybrid screen has revealed that the transcriptional repressor Sin3b interacts with Myc protein. Endogenous Myc and Sin3b co-localize and interact in the nuclei of human and rat cells, as assessed by co-immunoprecipitation, immunofluorescence, and proximity ligation assay. The interaction is Max-independent. A conserved Myc region (amino acids 186-203) is required for the interaction with Sin3 proteins. Histone deacetylase 1 is recruited to Myc-Sin3b complexes, and its deacetylase activity is required for the effects of Sin3b on Myc. Myc and Sin3a/b co-occupied many sites on the chromatin of human leukemia cells, although the presence of Sin3 was not associated with gene down-regulation. In leukemia cells and fibroblasts, Sin3b silencing led to Myc up-regulation, whereas Sin3b overexpression induced Myc deacetylation and degradation. An analysis of Sin3b expression in breast tumors revealed an association between low Sin3b expression and disease progression. The data suggest that Sin3b decreases Myc protein levels upon Myc deacetylation. As Sin3b is also required for transcriptional repression by Mxd-Max complexes, our results suggest that, at least in some cell types, Sin3b limits Myc activity through two complementary activities: Mxd-dependent gene repression and reduction of Myc levels. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Pelvic girdle and fin of Tiktaalik roseae

PubMed Central

Shubin, Neil H.; Daeschler, Edward B.; Jenkins, Farish A.

2014-01-01

A major challenge in understanding the origin of terrestrial vertebrates has been knowledge of the pelvis and hind appendage of their closest fish relatives. The pelvic girdle and appendage of tetrapods is dramatically larger and more robust than that of fish and contains a number of structures that provide greater musculoskeletal support for posture and locomotion. The discovery of pelvic material of the finned elpistostegalian, Tiktaalik roseae, bridges some of these differences. Multiple isolated pelves have been recovered, each of which has been prepared in three dimensions. Likewise, a complete pelvis and partial pelvic fin have been recovered in association with the type specimen. The pelves of Tiktaalik are paired and have broad iliac processes, flat and elongate pubes, and acetabulae that form a deep socket rimmed by a robust lip of bone. The pelvis is greatly enlarged relative to other finned tetrapodomorphs. Despite the enlargement and robusticity of the pelvis of Tiktaalik, it retains primitive features such as the lack of both an attachment for the sacral rib and an ischium. The pelvic fin of Tiktaalik (NUFV 108) is represented by fin rays and three endochondral elements: other elements are not preserved. The mosaic of primitive and derived features in Tiktaalik reveals that the enhancement of the pelvic appendage of tetrapods and, indeed, a trend toward hind limb-based propulsion have antecedents in the fins of their closest relatives. PMID:24449831

Fin propulsion on a human-powered submarine

NASA Astrophysics Data System (ADS)

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.

Propulsive Forces of a Biomimetic Undulating Fin

NASA Astrophysics Data System (ADS)

Kalumuck, Kenneth; Brandt, Alan; Armand, Mehran

2007-11-01

Understanding gained from much recent work on force production mechanisms of aquatic organisms holds great promise for improved undersea vehicle propulsion and maneuvering. One class of fish locomotion is that of the median fin utilized by animals such as squid, cuttlefish, knifefish, and seahorse. It is characterized by undulatory motion that creates traveling waves along the fin. Results of experiments conducted on a submerged mechanical underwater undulating fin test bed are presented. The 0.5 m long fin is mounted to a cylindrical body and consists of a flexible skin attached to ribs driven by an adjustable cam mechanism and variable speed motor that enables changing the characteristics of the undulating wave(s). Forces produced were measured in a captive mode under quiescent conditions as well in the presence of an ambient current. Propulsive forces are characterized as a function of the fin width, oscillation frequency, amplitude, and wavelength. Free swimming experiments were also conducted to determine the point of self propulsion. Flow field structure visualization using dye tracers is presented for selected cases. Estimates of performance and applications for use with larger scale vehicles are discussed.

THE POSTERIOR DISTRIBUTION OF sin(i) VALUES FOR EXOPLANETS WITH M{sub T} sin(i) DETERMINED FROM RADIAL VELOCITY DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, Shirley; Turner, Edwin L., E-mail: cwho@lbl.gov

2011-09-20

Radial velocity (RV) observations of an exoplanet system giving a value of M{sub T} sin(i) condition (i.e., give information about) not only the planet's true mass M{sub T} but also the value of sin(i) for that system (where i is the orbital inclination angle). Thus, the value of sin(i) for a system with any particular observed value of M{sub T} sin(i) cannot be assumed to be drawn randomly from a distribution corresponding to an isotropic i distribution, i.e., the presumptive prior distribution. Rather, the posterior distribution from which it is drawn depends on the intrinsic distribution of M{sub T} formore » the exoplanet population being studied. We give a simple Bayesian derivation of this relationship and apply it to several 'toy models' for the intrinsic distribution of M{sub T} , on which we have significant information from available RV data in some mass ranges but little or none in others. The results show that the effect can be an important one. For example, even for simple power-law distributions of M{sub T} , the median value of sin(i) in an observed RV sample can vary between 0.860 and 0.023 (as compared to the 0.866 value for an isotropic i distribution) for indices of the power law in the range between -2 and +1, respectively. Over the same range of indices, the 95% confidence interval on M{sub T} varies from 1.0001-2.405 ({alpha} = -2) to 1.13-94.34 ({alpha} = +2) times larger than M{sub T} sin(i) due to sin(i) uncertainty alone. More complex, but still simple and plausible, distributions of M{sub T} yield more complicated and somewhat unintuitive posterior sin(i) distributions. In particular, if the M{sub T} distribution contains any characteristic mass scale M{sub c} , the posterior sin(i) distribution will depend on the ratio of M{sub T} sin(i) to M{sub c} , often in a non-trivial way. Our qualitative conclusion is that RV studies of exoplanets, both individual objects and statistical samples, should regard the sin(i) factor as more than a

Actuation of a robotic fish caudal fin for low reaction torque

NASA Astrophysics Data System (ADS)

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.

SAP30L interacts with members of the Sin3A corepressor complex and targets Sin3A to the nucleolus

PubMed Central

Viiri, K. M.; Korkeamäki, H.; Kukkonen, M. K.; Nieminen, L. K.; Lindfors, K.; Peterson, P.; Mäki, M.; Kainulainen, H.; Lohi, O.

2006-01-01

Histone acetylation plays a key role in the regulation of gene expression. The chromatin structure and accessibility of genes to transcription factors is regulated by enzymes that acetylate and deacetylate histones. The Sin3A corepressor complex recruits histone deacetylases and in many cases represses transcription. Here, we report that SAP30L, a close homolog of Sin3-associated protein 30 (SAP30), interacts with several components of the Sin3A corepressor complex. We show that it binds to the PAH3/HID (Paired Amphipathic Helix 3/Histone deacetylase Interacting Domain) region of mouse Sin3A with residues 120–140 in the C-terminal part of the protein. We provide evidence that SAP30L induces transcriptional repression, possibly via recruitment of Sin3A and histone deacetylases. Finally, we characterize a functional nucleolar localization signal in SAP30L and show that SAP30L and SAP30 are able to target Sin3A to the nucleolus. PMID:16820529

3D modeling of dual-gate FinFET.

PubMed

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

2012-11-13

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.

3D modeling of dual-gate FinFET

NASA Astrophysics Data System (ADS)

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

2012-11-01

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 V g1 > V g2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device.

PNS predictions for supersonic/hypersonic flows over finned missile configurations

NASA Technical Reports Server (NTRS)

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.

Wind Fins: Novel Lower-Cost Wind Power System

DOE Office of Scientific and Technical Information (OSTI.GOV)

David C. Morris; Dr. Will D. Swearingen

This project evaluated the technical feasibility of converting energy from the wind with a novel “wind fin” approach. This patent-pending technology has three major components: (1) a mast, (2) a vertical, hinged wind structure or fin, and (3) a power takeoff system. The wing structure responds to the wind with an oscillating motion, generating power. The overall project goal was to determine the basic technical feasibility of the wind fin technology. Specific objectives were the following: (1) to determine the wind energy-conversion performance of the wind fin and the degree to which its performance could be enhanced through basic designmore » improvements; (2) to determine how best to design the wind fin system to survive extreme winds; (3) to determine the cost-effectiveness of the best wind fin designs compared to state-of-the-art wind turbines; and (4) to develop conclusions about the overall technical feasibility of the wind fin system. Project work involved extensive computer modeling, wind-tunnel testing with small models, and testing of bench-scale models in a wind tunnel and outdoors in the wind. This project determined that the wind fin approach is technically feasible and likely to be commercially viable. Project results suggest that this new technology has the potential to harvest wind energy at approximately half the system cost of wind turbines in the 10kW range. Overall, the project demonstrated that the wind fin technology has the potential to increase the economic viability of small wind-power generation. In addition, it has the potential to eliminate lethality to birds and bats, overcome public objections to the aesthetics of wind-power machines, and significantly expand wind-power’s contribution to the national energy supply.« less

Hydrodynamics of a freely movable flexible fin near the ground

NASA Astrophysics Data System (ADS)

Jeong, Young Dal; Lee, Jae Hwa

2017-11-01

In the present study, a freely movable flexible fin is numerically modelled to investigate the flapping dynamics of the fin near the ground in a Poiseuille flow. A leading edge of the fin is fixed in the streamwise direction, whereas the lateral motion is spontaneously determined by hydrodynamic interaction between the fin and surrounding fluid. When the fin is initially positioned at yo, the fin passively migrates toward another wall-normal position for an equilibrium state by the interaction between passively flapping flexible body and ground. At the equilibrium position, the drag coefficient of the fin (CD) significantly decreases due to decaying of the flapping and low flow velocity and the fin can swim consistently without the time-averaged lateral force. Two distinctive behavior at the transient state (flapping and non-flapping migration modes) and three distinctive behaviors at the equilibrium state (deflected-straight, large- and small-amplitude flapping modes) are observed depending on the bending rigidity (γ) and mass ratio (μ) of the fin. The equilibrium position of the fin is investigated as a function of initial position (yo) , bending rigidity (γ) , mass ratio (μ) and the Reynolds number (Re). This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1A09000537) and the Ministry of Science, ICT & Future Planning (NRF-2017R1A5A1015311).

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

NASA Astrophysics Data System (ADS)

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.

Finned Tube With Vortex Generators For A Heat Exchanger.

DOEpatents

Sohal, Manohar S.; O'Brien, James E.

2005-12-20

A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

Finned Tube With Vortex Generators For A Heat Exchanger.

DOEpatents

Sohal, Monohar S.; O'Brien, James E.

2004-09-14

A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

Sailboard Fin Design

NASA Technical Reports Server (NTRS)

1992-01-01

In high performance boardsailing, demands on the vertical fin or "skeg" often produce "spinout" - when the skeg loses horizontal lift creating a force imbalance and causing the tail of the board to slide sideways. Richard Caldwell, RACE Technology, Inc. used NASA airfoil technology to solve this problem and formed a business based on his solution. After determining that the spinout resulted from air ventilating down the low pressure side of the underwater fin, he adapted the airfoil technology to the design of a short board skeg, which would overcome the problem and lower the drag, resulting in improved performance. He patented his RACE 145 foil section, formed his company and later returned to Langley for additional technical assistance. The company's newest product is a rigid sail that also incorporates NASA technology and has excellent performance. This company no longer exists - product is no longer in production.

Mapping interactions between the RNA chaperone FinO and its RNA targets

PubMed Central

Arthur, David C.; Tsutakawa, Susan; Tainer, John A.; Frost, Laura S.; Glover, J. N. Mark

2011-01-01

Bacterial conjugation is regulated by two-component repression comprising the antisense RNA FinP, and its protein co-factor FinO. FinO mediates base-pairing of FinP to the 5′-untranslated region (UTR) of traJ mRNA, which leads to translational inhibition of the transcriptional activator TraJ and subsequent down regulation of conjugation genes. Yet, little is known about how FinO binds to its RNA targets or how this interaction facilitates FinP and traJ mRNA pairing. Here, we use solution methods to determine how FinO binds specifically to its minimal high affinity target, FinP stem–loop II (SLII), and its complement SLIIc from traJ mRNA. Ribonuclease footprinting reveals that FinO contacts the base of the stem and the 3′ single-stranded tails of these RNAs. The phosphorylation or oxidation of the 3′-nucleotide blocks FinO binding, suggesting FinO binds the 3′-hydroxyl of its RNA targets. The collective results allow the generation of an energy-minimized model of the FinO–SLII complex, consistent with small-angle X-ray scattering data. The repression complex model was constrained using previously reported cross-linking data and newly developed footprinting results. Together, these data lead us to propose a model of how FinO mediates FinP/traJ mRNA pairing to down regulate bacterial conjugation. PMID:21278162

Transonic static and dynamic stability characteristics of a finned projectile configuration

NASA Technical Reports Server (NTRS)

Boyden, R. P.; Brooks, C. W., Jr.; Davenport, E. E.

1978-01-01

Static and dynamic stability tests were made of a finned projectile configuration with the aft-mounted fins arranged in a cruciform pattern. The tests were made at free stream Mach numbers of 0.7, 0.9, 1.1, and 1.2 in the Langley 8-foot transonic pressure tunnel. Some of the parameters measured during the tests were lift, drag, pitching moment, pitch damping, and roll damping. Configurations tested included the body with undeflected fins, the body with various fin deflections for control, and the body with fins removed. Theoretical estimates of the stability derivatives were made for the fins on configuration.

Chromium Is Elevated in Fin Whale (Balaenoptera physalus) Skin Tissue and Is Genotoxic to Fin Whale Skin Cells

PubMed Central

Wise, Catherine F.; Wise, Sandra S.; Thompson, W. Douglas; Perkins, Christopher; Wise, John Pierce

2015-01-01

Hexavalent chromium (Cr(VI)) is present in the marine environment and is a known carcinogen and reproductive toxicant. Cr(VI) is the form of chromium that is well absorbed through the cell membrane. It is also the most prevalent form in seawater. We measured the total Cr levels in skin biopsies obtained from healthy free-ranging fin whales from the Gulf of Maine and found elevated levels relative to marine mammals in other parts of the world. The levels in fin whale biopsies ranged from 1.71 ug/g to 19.6 ug/g with an average level of 10.07 ug/g. We also measured the cytotoxicity and genotoxicity of Cr(VI) in fin whale skin cells. We found that particulate and soluble Cr(VI) are both cytotoxic and genotoxic to fin whale skin cells in a concentration-dependent manner. The concentration range used in our cell culture studies used environmentally relevant concentrations based on the biopsy measurements. These data suggest that Cr(VI) may be a concern for whales in the Gulf of Maine. PMID:25805270

Study of Swept Angle Effects on Grid Fins Aerodynamics Performance

NASA Astrophysics Data System (ADS)

Faza, G. A.; Fadillah, H.; Silitonga, F. Y.; Agoes Moelyadi, Mochamad

2018-04-01

Grid fin is an aerodynamic control surface that usually used on missiles and rockets. In the recent several years many researches have conducted to develop a more efficient grid fins. There are many possibilities of geometric combination could be done to improve aerodynamics characteristic of a grid fin. This paper will only discuss about the aerodynamics characteristics of grid fins compared by another grid fins with different swept angle. The methodology that used to compare the aerodynamics is Computational Fluid Dynamics (CFD). The result of this paper might be used for future studies to answer our former question or as a reference for related studies.

Correlated evolution of body and fin morphology in the cichlid fishes.

PubMed

Feilich, Kara L

2016-10-01

Body and fin shapes are chief determinants of swimming performance in fishes. Different configurations of body and fin shapes can suit different locomotor specializations. The success of any configuration is dependent upon the hydrodynamic interactions between body and fins. Despite the importance of body-fin interactions for swimming, there are few data indicating whether body and fin configurations evolve in concert, or whether these structures vary independently. The cichlid fishes are a diverse family whose well-studied phylogenetic relationships make them ideal for the study of macroevolution of ecomorphology. This study measured body, and caudal and median fin morphology from radiographs of 131 cichlid genera, using morphometrics and phylogenetic comparative methods to determine whether these traits exhibit correlated evolution. Partial least squares canonical analysis revealed that body, caudal fin, dorsal fin, and anal fin shapes all exhibited strong correlated evolution consistent with locomotor ecomorphology. Major patterns included the evolution of deep body profiles with long fins, suggestive of maneuvering specialization; and the evolution of narrow, elongate caudal peduncles with concave tails, a combination that characterizes economical cruisers. These results demonstrate that body shape evolution does not occur independently of other traits, but among a suite of other morphological changes that augment locomotor specialization. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Effect of pectoral fin kinematics on manta ray propulsion

NASA Astrophysics Data System (ADS)

Lu, Hao; Yeo, Khoon Seng; Chew, Chee-Meng

2018-05-01

Recent advancement of bio-inspired underwater vehicles has led to a growing interest in understanding the fluid mechanics of fish locomotion, which involves complex interaction between the deforming structure and its surrounding fluid. Unlike most natural swimmers that undulate their body and caudal fin, manta rays employ an oscillatory mode by flapping their large, flattened pectoral fins to swim forward. Such a lift-based mode can achieve a substantially high propulsive efficiency, which is beneficial to long-distance swimming. In this study, numerical simulations are carried out on a realistic manta ray model to investigate the effect of pectoral fin kinematics on the propulsive performance and flow structure. A traveling wave model, which relates a local deflection angle to radial and azimuthal wavelengths, is applied to generate the motion of the pectoral fins. Hydrodynamic forces and propulsive efficiency are reported for systematically varying kinematic parameters such as wave amplitude and wavelengths. Key flow features, including a leading edge vortex (LEV) that forms close to the tip of each pectoral fin, and a wake consisting of interconnected vortex rings, are identified. In addition, how different fin motions alter the LEV behavior and hence affect the thrust and efficiency is illustrated.

The Influence of Culture on the International Management of Shark Finning

NASA Astrophysics Data System (ADS)

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.

The influence of culture on the international management of shark finning.

PubMed

Dell'Apa, Andrea; Smith, M Chad; 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.

Assessment of Thermal Performance of Functionally Graded Materials in Longitudinal Fins

NASA Astrophysics Data System (ADS)

Hassanzadeh, R.; Bilgili, M.

2018-01-01

Assessment of the thermal characteristics of materials in heat exchangers with longitudinal fins is performed in the case where a conventional homogeneous material of a longitudinal fin is replaced by a functionally graded one, in which the fin material properties, such as the conductivity, are assumed to be graded as linear and power-law functions along the normal axis from the fin base to the fin tip. The resulting equations are calculated under two (Dirichlet and Neumann) boundary conditions. The equations are solved by an approximate analytical method with the use of the mean value theorem. The results show that the inhomogeneity index of a functionally graded material plays an important role for the thermal energy characteristics in such heat exchangers. In addition, it is observed that the use of such a material in longitudinal fins enhances the rate of heat transfer between the fin surface and surrounding fluid. Hopefully, the results obtained in the study will arouse interest of designers in heat exchange industry.

Development and Validation of the Single Item Narcissism Scale (SINS)

PubMed Central

Konrath, Sara; Meier, Brian P.; Bushman, Brad J.

2014-01-01

Main Objectives The narcissistic personality is characterized by grandiosity, entitlement, and low empathy. This paper describes the development and validation of the Single Item Narcissism Scale (SINS). Although the use of longer instruments is superior in most circumstances, we recommend the SINS in some circumstances (e.g. under serious time constraints, online studies). Methods In 11 independent studies (total N = 2,250), we demonstrate the SINS' psychometric properties. Results The SINS is significantly correlated with longer narcissism scales, but uncorrelated with self-esteem. It also has high test-retest reliability. We validate the SINS in a variety of samples (e.g., undergraduates, nationally representative adults), intrapersonal correlates (e.g., positive affect, depression), and interpersonal correlates (e.g., aggression, relationship quality, prosocial behavior). The SINS taps into the more fragile and less desirable components of narcissism. Significance The SINS can be a useful tool for researchers, especially when it is important to measure narcissism with constraints preventing the use of longer measures. PMID:25093508

Development and validation of the Single Item Narcissism Scale (SINS).

PubMed

Konrath, Sara; Meier, Brian P; Bushman, Brad J

2014-01-01

The narcissistic personality is characterized by grandiosity, entitlement, and low empathy. This paper describes the development and validation of the Single Item Narcissism Scale (SINS). Although the use of longer instruments is superior in most circumstances, we recommend the SINS in some circumstances (e.g. under serious time constraints, online studies). In 11 independent studies (total N = 2,250), we demonstrate the SINS' psychometric properties. The SINS is significantly correlated with longer narcissism scales, but uncorrelated with self-esteem. It also has high test-retest reliability. We validate the SINS in a variety of samples (e.g., undergraduates, nationally representative adults), intrapersonal correlates (e.g., positive affect, depression), and interpersonal correlates (e.g., aggression, relationship quality, prosocial behavior). The SINS taps into the more fragile and less desirable components of narcissism. The SINS can be a useful tool for researchers, especially when it is important to measure narcissism with constraints preventing the use of longer measures.

Investigation of thermal effects on FinFETs in the quasi-ballistic regime

NASA Astrophysics Data System (ADS)

Yin, Longxiang; Shen, Lei; Di, Shaoyan; Du, Gang; Liu, Xiaoyan

2018-04-01

In this work, the thermal effects of FinFETs in the quasi-ballistic regime are investigated using the Monte Carlo method. Bulk Si nFinFETs with the same fin structure and two different gate lengths L g = 20 and 80 nm are investigated and compared to evaluate the thermal effects on the performance of FinFETs in the quasi-ballistic regime. The on current of the 20 nm FinFET with V gs = 0.7 V does not decrease with increasing lattice temperature (T L) at a high V ds. The electrostatic properties in the 20 nm FinFET are more affected by T L than those in the 80 nm FinFET. However, the electron transport in the 20 nm FinFET is less affected by T L than that in the 80 nm FinFET. The electrostatic properties being more sensitive and the electron transport being less sensitive to thermal effects in the quasi-ballistic regime than in the diffusive regime should be considered for effective device modeling and design.

The evolutionary history of the development of the pelvic fin/hindlimb

PubMed Central

Don, Emily K; Currie, Peter D; Cole, Nicholas J

2013-01-01

The arms and legs of man are evolutionarily derived from the paired fins of primitive jawed fish. Few evolutionary changes have attracted as much attention as the origin of tetrapod limbs from the paired fins of ancestral fish. The hindlimbs of tetrapods are derived from the pelvic fins of ancestral fish. These evolutionary origins can be seen in the examination of shared gene and protein expression patterns during the development of pelvic fins and tetrapod hindlimbs. The pelvic fins of fish express key limb positioning, limb bud induction and limb outgrowth genes in a similar manner to that seen in hindlimb development of higher vertebrates. We are now at a point where many of the key players in the development of pelvic fins and vertebrate hindlimbs have been identified and we can now readily examine and compare mechanisms between species. This is yielding fascinating insights into how the developmental programme has altered during evolution and how that relates to anatomical change. The role of pelvic fins has also drastically changed over evolutionary history, from playing a minor role during swimming to developing into robust weight-bearing limbs. In addition, the pelvic fins/hindlimbs have been lost repeatedly in diverse species over evolutionary time. Here we review the evolution of pelvic fins and hindlimbs within the context of the changes in anatomical structure and the molecular mechanisms involved. PMID:22913749

Precision and accuracy of age estimates obtained from anal fin spines, dorsal fin spines, and sagittal otoliths for known-age largemouth bass

USGS Publications Warehouse

Klein, Zachary B.; Bonvechio, Timothy F.; Bowen, Bryant R.; Quist, Michael C.

2017-01-01

Sagittal otoliths are the preferred aging structure for Micropterus spp. (black basses) in North America because of the accurate and precise results produced. Typically, fisheries managers are hesitant to use lethal aging techniques (e.g., otoliths) to age rare species, trophy-size fish, or when sampling in small impoundments where populations are small. Therefore, we sought to evaluate the precision and accuracy of 2 non-lethal aging structures (i.e., anal fin spines, dorsal fin spines) in comparison to that of sagittal otoliths from known-age Micropterus salmoides (Largemouth Bass; n = 87) collected from the Ocmulgee Public Fishing Area, GA. Sagittal otoliths exhibited the highest concordance with true ages of all structures evaluated (coefficient of variation = 1.2; percent agreement = 91.9). Similarly, the low coefficient of variation (0.0) and high between-reader agreement (100%) indicate that age estimates obtained from sagittal otoliths were the most precise. Relatively high agreement between readers for anal fin spines (84%) and dorsal fin spines (81%) suggested the structures were relatively precise. However, age estimates from anal fin spines and dorsal fin spines exhibited low concordance with true ages. Although use of sagittal otoliths is a lethal technique, this method will likely remain the standard for aging Largemouth Bass and other similar black bass species.

Slotting Fins of Heat Exchangers to Provide Thermal Breaks

NASA Technical Reports Server (NTRS)

Scull, Timothy D.

2003-01-01

Heat exchangers that include slotted fins (in contradistinction to continuous fins) have been invented. The slotting of the fins provides thermal breaks that reduce thermal conduction along flow paths (longitudinal thermal conduction), which reduces heat-transfer efficiency. By increasing the ratio between transverse thermal conduction (the desired heat-transfer conduction) and longitudinal thermal conduction, slotting of the fins can be exploited to (1) increase heat-transfer efficiency (thereby reducing operating cost) for a given heat-exchanger length or to (2) reduce the length (thereby reducing the weight and/or cost) of the heat exchanger needed to obtain a given heat transfer efficiency. By reducing the length of a heat exchanger, one can reduce the pressure drop associated with the flow through it. In a case in which slotting enables the use of fins with thermal conductivity greater than could otherwise be tolerated on the basis of longitudinal thermal conduction, one can exploit the conductivity to make the fins longer (in the transverse direction) than they otherwise could be, thereby making it possible to make a heat exchanger that contains fewer channels and therefore, that weighs less, contains fewer potential leak paths, and can be constructed from fewer parts and, hence, reduced cost.

Vortex Shedding from Finned Circular Cylinders

DTIC Science & Technology

1980-11-01

FINNED CIRCULAR CYLINDERSo ,rm"" 1..UTNOI .)R*., r. *.040, 111SPOR- / T NuMBII f.John G. elute asOHans J.’/, ugt -. . . , ,<-. -. ,:. =., .. Siil P3RPIO...fins and other sharp protuberances. These purely two-dimensional flows then may be used in a strip theory to include at least some aspects of three...boundary- layer theory . Such a prediction method, together with a technique to provide for a vortex sheet at the separation point, will be included in

Parametric study of graphite foam fins and application in heat exchangers

NASA Astrophysics Data System (ADS)

Collins, Michael

This thesis focuses on the simulation and experimental studies of finned graphite foam extended surfaces to test their heat transfer characteristics and potential applications in condensers. Different fin designs were developed to conduct a parametric study on the thermal effectiveness with respect to thickness, spacing and fin offset angle. Each fin design was computationally simulated to estimate the heat transfer under specific conditions. The simulations showed that this optimal fin configuration could conduct more than 297% the amount of thermal energy as compared to straight aluminum fins. Graphite foam fins were then implemented into a simulation of the condenser system. The condenser was simulated with six different orientations of baffles to examine the incoming vapor and resulting two-phase flow patterns. The simulations showed that using both horizontal and vertical baffling provided the configuration with the highest heat transfer and minimized the bypass regions where the vapor would circumvent the graphite foam. This baffle configuration increased the amount of vapor flow through the inner graphite fins and cold water pipes, which gave this configuration the highest heat transfer. The results from experimental tests using the condenser system confirmed that using three baffles will increase performance consistent with the simulation results. The experimental data showed that the condenser using graphite foam had five times the heat transfer compared to the condenser using only aluminum fins. Incorporating baffles into the condenser using graphite foam enabled this system to conduct nearly ten times more heat transfer than the condenser system which only had aluminum fins without baffles. The results from this research indicate that graphite foam is a far superior material heat transfer enhancement material for heat transfer compared to aluminum used as an extended surface. The longitudinal and horizontal baffles incorporated into the condenser system

F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators

DTIC Science & Technology

2009-09-01

collocated design to alleviate the vibrations of the first two modes of the ventral fin. A switching amplifier was de - signed and custom built to drive the...6M per year [22]. 1 Figure 1.1: LANTIRN Pod and Ventral Fin Locations [cour- tesy USAF] Buffet induced vibrations affect more than just vertical tail...appropriate sensors and actuators for the ventral fin. Several de - viations were necessary, including individual actuator size and orientation and the

Highly flexible SRAM cells based on novel tri-independent-gate FinFET

NASA Astrophysics Data System (ADS)

Liu, Chengsheng; Zheng, Fanglin; Sun, Yabin; Li, Xiaojin; Shi, Yanling

2017-10-01

In this paper, a novel tri-independent-gate (TIG) FinFET is proposed for highly flexible SRAM cells design. To mitigate the read-write conflict, two kinds of SRAM cells based on TIG FinFETs are designed, and high tradeoff are obtained between read stability and speed. Both cells can offer multi read operations for frequency requirement with single voltage supply. In the first TIG FinFET SRAM cell, the strength of single-fin access transistor (TIG FinFET) can be flexibly adjusted by selecting five different modes to meet the needs of dynamic frequency design. Compared to the previous double-independent-gate (DIG) FinFET SRAM cell, 12.16% shorter read delay can be achieved with only 1.62% read stability decrement. As for the second TIG FinFET SRAM cell, pass-gate feedback technology is applied and double-fin TIG FinFETs are used as access transistors to solve the severe write-ability degradation. Three modes exist to flexibly adjust read speed and stability, and 68.2% larger write margin and 51.7% shorter write delay are achieved at only the expense of 26.2% increase in leakage power, with the same layout area as conventional FinFET SRAM cell.

Fins effectiveness and efficiency with position function of rhombus sectional area in unsteady condition

NASA Astrophysics Data System (ADS)

Nugroho, Tito Dwi; Purwadi, P. K.

2017-01-01

The function of the fin is to extend surfaces so that objects fitted with fin can remove the heat to the surrounding environment so that the cooling process can take place more quickly. The purpose of this study is to calculate and determine the effect of (a) the convective heat transfer coefficient of fluid on the value of the fin on the efficiency and effectiveness of non-steady state, and (b) the fin material to the value of the fins on the efficiency and effectiveness of non-steady state. The studied fins are in the form of straight fins with rhombus sectional area which is a function of position x with the short diagonal length of D1 and D2 as long diagonal length, L as fin's length and α as fin's tilt angle. Research solved numerical computation, using a finite difference method on the explicit way. At first, the fin has the same initial temperature with essentially temperature Ti = Tb, then abruptly fin conditioned on fluid temperature environment T∞. Fin's material is assumed with uniform properties, does not change with changes in temperature, and fin does not change the shape and volume during the process. The temperature of the fluid around the fins and the value of the convective heat transfer coefficient are permanently constant, and there is no energy generation in the fin. Fin's heat transfer conduction only take place in one direction, namely in the direction perpendicular to the fin base (or x-direction). The entire surface of the fin makes the process of heat transfer to a fluid environment around the fins. The results show that (a) the greater the value of heat transfer coefficient of convection h, the smaller the efficiency fin and effectiveness fins (b) In circumstances of unsteady state, the efficiency and effectivity influenced by the value of density, specific heat, heat transfer coefficient of conduction and thermal diffusivity fin material.

Original antigenic sin: A comprehensive review.

PubMed

Vatti, Anup; Monsalve, Diana M; Pacheco, Yovana; Chang, Christopher; Anaya, Juan-Manuel; Gershwin, M Eric

2017-09-01

The concept of "original antigenic sin" was first proposed by Thomas Francis, Jr. in 1960. This phenomenon has the potential to rewrite what we understand about how the immune system responds to infections and its mechanistic implications on how vaccines should be designed. Antigenic sin has been demonstrated to occur in several infectious diseases in both animals and humans, including human influenza infection and dengue fever. The basis of "original antigenic sin" requires immunological memory, and our immune system ability to autocorrect. In the context of viral infections, it is expected that if we are exposed to a native strain of a pathogen, we should be able to mount a secondary immune response on subsequent exposure to the same pathogen. "Original antigenic sin" will not contradict this well-established immunological process, as long as the subsequent infectious antigen is identical to the original one. But "original antigenic sin" implies that when the epitope varies slightly, then the immune system relies on memory of the earlier infection, rather than mount another primary or secondary response to the new epitope which would allow faster and stronger responses. The result is that the immunological response may be inadequate against the new strain, because the immune system does not adapt and instead relies on its memory to mount a response. In the case of vaccines, if we only immunize to a single strain or epitope, and if that strain/epitope changes over time, then the immune system is unable to mount an accurate secondary response. In addition, depending of the first viral exposure the secondary immune response can result in an antibody-dependent enhancement of the disease or at the opposite, it could induce anergy. Both of them triggering loss of pathogen control and inducing aberrant clinical consequences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Water flow and fin shape polymorphism in coral reef fishes.

PubMed

Binning, Sandra A; Roche, Dominique G

2015-03-01

Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (<100 m) along a reef profile (reef slope, crest, and back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for

The X-38 V-201 Fin Fold Actuation Mechanism

NASA Technical Reports Server (NTRS)

Lupo, Christian; Robertson, Brandan; Gafka, George

2004-01-01

The X-38 Vehicle 201 (V-201) is a space flight prototype lifting body vehicle that was designed to launch to orbit in the Space Shuttle orbiter payload bay. Although the project was cancelled in May 2003, many of the systems were nearly complete. This paper will describe the fin folding actuation mechanism flight subsystems and development units as well as lessons learned in the design, assembly, development testing, and qualification testing. The two vertical tail fins must be stowed (folded inboard) to allow the orbiter payload bay doors to close. The fin folding actuation mechanism is a remotely or extravehicular activity (EVA) actuated single fault tolerant system consisting of seven subsystems capable of repeatedly deploying or stowing the fins.

Hydrodynamical analysis of the effect of fish fins morphology

NASA Astrophysics Data System (ADS)

Azwadi Che Sidik, Nor; Yen, Tey Wah

2013-12-01

The previous works on the biomechanics of fishes focuses on the locomotion effect of the fish bodies. However, there is quite a insufficiency in unveiling the respective function of fins when the fishes pose statics and exposed to fluid flow. Accordingly, this paper's focus is to investigate the hydrodynamic effect of the fins configuration to the fluid flow of shark-shaped-inspired structure. The drag and lift coefficient is computed for different cases of fish fins addition and configuration. The k-epsilon turbulence model is deployed using finite volume method with the aid of commercial software ANSYS CFX. The finding will demystify some of the functions of the fish's fins in term of their contribution to the hydrodynamic flow around the fishes.

On the Hydrodynamics of Anomalocaris Tail Fins.

PubMed

Sheppard, K A; Rival, D E; Caron, J-B

2018-04-25

Anomalocaris canadensis, a soft-bodied stem-group arthropod from the Burgess Shale, is considered the largest predator of the Cambrian period. Thanks to a series of lateral flexible lobes along its dorso-ventrally compressed body, it is generally regarded as an efficient swimmer, well-adapted to its predatory lifestyle. Previous theoretical hydrodynamic simulations have suggested a possible optimum in swimming performance when the lateral lobes performed as a single undulatory lateral fin, comparable to the pectoral fins in skates and rays. However, the role of the unusual fan-like tail of Anomalocaris has not been previously explored. Swimming efficiency and maneuverability deduced from direct hydrodynamic analysis are here studied in a towing tank facility using a three-vane physical model designed as an abstraction of the tail fin. Through direct force measurements, it was found that the model exhibited a region of steady-state lift and drag enhancement at angles of attack greater than 25° when compared to a triangular-shaped reference model. This would suggest that the resultant normal force on the tail fin of Anomalocaris made it well-suited for turning maneuvers, giving it the ability to turn quickly and through small radii of curvature. These results are consistent with an active predatory lifestyle, although detailed kinematic studies integrating the full organism, including the lateral lobes, would be required to test the effect of the tail fin on overall swimming performance. This study also highlights a possible example of evolutionary convergence between the tails of Anomalocaris and birds, which, in both cases, are well-adapted to efficient turning maneuvers.

Medio Communication: A Conceptualization.

ERIC Educational Resources Information Center

Blake, Reed H.

The classification of communication activity into interpersonal and mass communication is inadequate. A third category, "medio" communication, is also needed. Examples of this third type include point-to-point telecommunication (such as the telephone or mobile radio), surveillance telecommunication, and closed-circuit television. Medio…

Fish Pectoral Fin Hydrodynamics; Part III: Low Dimensional Models via POD Analysis

NASA Astrophysics Data System (ADS)

Bozkurttas, M.; Madden, P.

2005-11-01

The highly complex kinematics of the pectoral fin and the resulting hydrodynamics does not lend itself easily to analysis based on simple notions of pitching/heaving/paddling kinematics or lift/drag based propulsive mechanisms. A more inventive approach is needed to dissect the fin gait and gain insight into the hydrodynamic performance of the pectoral fin. The focus of the current work is on the hydrodynamics of the pectoral fin of a bluegill sunfish in steady forward motion. The 3D, time-dependent fin kinematics is obtained via a stereo-videographic technique. We employ proper orthogonal decomposition to extract the essential features of the fin gait and then use CFD to examine the hydrodynamics of simplified gaits synthesized from the POD modes. The POD spectrum shows that the first two, three and five POD modes capture 55%, 67%, and 80% of the motion respectively. The first three modes are in particular highly distinct: Mode-1 is a ``cupping'' motion where the fin cups forward as it is abducted; Mode-2 is an ``expansion'' motion where the fin expands to present a larger area during adduction and finally Mode-3 involves a ``spanwise flick'' of the dorsal edge of the fin. Numerical simulation of flow past fin gaits synthesized from these modes lead to insights into the mechanisms of thrust production; these are discussed in detail.

Anatomy and early development of the pectoral girdle, fin, and fin spine of sturgeons (Actinopterygii: Acipenseridae).

PubMed

Dillman, Casey B; Hilton, Eric J

2015-03-01

Acipenseriformes hold an important place in the evolutionary history of bony fishes. Given their phylogenetic position as extant basal Actinopterygii, it is generally held that a thorough understanding of their morphology will greatly contribute to the knowledge of the evolutionary history and the origin of diversity for the major osteichthyan clades. To this end, we examined comparative developmental series from the pectoral girdle in Acipenser fulvescens, A. medirostris, A. transmontanus, and Scaphirhynchus albus to document, describe, and compare ontogenetic and allometric differences in the pectoral girdle. We find, not surprisingly, broad congruence between taxa in the basic pattern of development of the dermal and chondral elements of the pectoral girdle. However, we also find clear differences in the details of structure and development among the species examined in the dermal elements, including the clavicle, cleithrum, supracleithrum, posttemporal, and pectoral-fin spine. We also find differences in the internal fin elements such as the distal radials as well as in the number of fin rays and their association with the propterygium. Further, there are clear ontogenetic differences during development of the dermal and chondral elements in these species and allometric variation in the pectoral-fin spine. The characters highlighted provide a suite of elements for further examination in studies of the phylogeny of sturgeons. Determining the distribution of these characters in other sturgeons may aid in further resolution of phylogenetic relationships, and these data highlight the role that ontogenetic and comparative developmental studies provide in systematics. © 2014 Wiley Periodicals, Inc.

14 CFR 23.445 - Outboard fins or winglets.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Outboard fins or winglets. 23.445 Section 23.445 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces or...

14 CFR 23.445 - Outboard fins or winglets.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Outboard fins or winglets. 23.445 Section 23.445 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces or...

Integration of oceanographic data with fin whale calling presence in the Bering Sea

NASA Astrophysics Data System (ADS)

Dasarathy, S.; Berchok, C.; Stabeno, P. J.; Crance, J.

2016-02-01

Through the integration of environmental data with passive acoustic monitoring, it is possible to investigate whether fin whale (Balaenoptera physalus) presence is influenced by environmental factors. Fin whale calling activity and concurrent environmental variables were analyzed from May 2012 to September 2013. These data were collected from passive acoustic and oceanographic moorings located in the Bering Sea. Fin whale calling presence was strongly correlated with three of the eight parameters analyzed: ice concentration, chlorophyll (a proxy for primary production), and temperature. Fin whale calling was negatively correlated with ice concentration; as ice concentration increased, fin whale calling decreased. A strong positive correlation was observed between fin whale calling and chlorophyll. A large spike in chlorophyll concentration in July 2013 preceded fin whale calling at the northern location. Fin whale calling also increased concurrently with a mixing of the water column (evidenced in the temperature data) at a depth of 30 to 50m. Peaks in chlorophyll concentration occurred after the mixing of the water column, and followed an increase in fin whale calling. These data illustrate the relationship between fin whale presence and environmental variables in the Bering Sea. These correlations may be used to predict the impact of climate change on fin whale populations in the rapidly changing environment of the Bering Sea.

Oil-flow study of a Space Shuttle orbiter tip-fin controller

NASA Technical Reports Server (NTRS)

Helms, V. T., III

1983-01-01

Possible use of tip-fin controllers instead of a vertical tail on advanced winged entry vehicles was examined. Elimination of the vertical tail and using tip-fins offers the advantages of positive yaw control at high angles of attack and a potential weight savings. Oil-flow technique was used to obtain surface flow patterns on a tip-fin installed on a 0.01-scale Space Shuttle orbiter model for the purpose of assessing the extent of flow interference effects on the wing and tip-fin which might lead to serious heating problems. Tests were conducted in air at Mach 10 for a free-stream Reynolds numbers of .000113 at 20, 30, and 40 degree angle of attack and sideslip angles of 0 and 2 degree. Elevon deflections of -10, 0, and 10 degree and tip-fin control-surface deflections of 0, 20, and 40 degree were employed. Test results were also used to aid in the interpretation of heating data obtained on a Shuttle orbiter tip-fin on another model in a different facility. A limited comparison of oil-flow patterns and heat-transfer data is included. It was determined that elevon deflection angles from -10 to 10 degree and sideslip angles up to 2 degree have very little effect on tip-fin surface flow patterns. Also, there is a minimum of interference between the tip-fin and the wing. The most significant flow interactions occur on the tip-fin onboard surface as a result of its control-surface deflections.

Quantification of local strain distributions in nanoscale strained SiGe FinFET structures

NASA Astrophysics Data System (ADS)

Mochizuki, Shogo; Murray, Conal E.; Madan, Anita; Pinto, Teresa; Wang, Yun-Yu; Li, Juntao; Weng, Weihao; Jagannathan, Hemanth; Imai, Yasuhiko; Kimura, Shigeru; Takeuchi, Shotaro; Sakai, Akira

2017-10-01

Strain within nanoscale strained SiGe FinFET structures has been investigated using a combination of X-ray diffraction and transmission electron microscopy-based nanobeam diffraction (NBD) techniques to reveal the evolution of the stress state within the FinFETs. Reciprocal space maps collected using high-resolution X-ray diffraction exhibited distinct features corresponding to the SiGe fin width, pitch, and lattice deformation and were analyzed to quantify the state of stress within the fins. Although the majority of the SiGe fin volume exhibited a uniaxial stress state due to elastic relaxation of the transverse in-plane stress, NBD measurements confirmed a small interaction region near the SOI interface that is mechanically constrained by the underlying substrate. We have quantitatively characterized the evolution of the fin stress state from biaxial to uniaxial as a function of fin aspect ratio and Ge fraction and confirmed that the fins obey elastic deformation based on a model that depends on the relative difference between the equilibrium Si and SiGe lattice constants and relative fraction of in-plane stress transverse to the SiGe fins. Spatially resolved, nanobeam X-ray diffraction measurements conducted near the SiGe fin edge indicate the presence of additional elastic relaxation from a uniaxial stress state to a fully relaxed state at the fin edge. Mapping of the lattice deformation within 500 nm of this fin edge by NBD revealed large gradients, particularly at the top corner of the fin. The values of the volume averaged lattice deformation obtained by nanoXRD and NBD are qualitatively consistent. Furthermore, the modulation of strain at the fin edge obtained by quantitative analysis of the nanoXRD results agrees with the lattice deformation profile obtained by NBD.

Heat transfer and pressure drop characteristics of the tube bank fin heat exchanger with fin punched with flow redistributors and curved triangular vortex generators

NASA Astrophysics Data System (ADS)

Liu, Song; Jin, Hua; Song, KeWei; Wang, LiangChen; Wu, Xiang; Wang, LiangBi

2017-10-01

The heat transfer performance of the tube bank fin heat exchanger is limited by the air-side thermal resistance. Thus, enhancing the air-side heat transfer is an effective method to improve the performance of the heat exchanger. A new fin pattern with flow redistributors and curved triangular vortex generators is experimentally studied in this paper. The effects of the flow redistributors located in front of the tube stagnation point and the curved vortex generators located around the tube on the characteristics of heat transfer and pressure drop are discussed in detail. A performance comparison is also carried out between the fins with and without flow redistributors. The experimental results show that the flow redistributors stamped out from the fin in front of the tube stagnation points can decrease the friction factor at the cost of decreasing the heat transfer performance. Whether the combination of the flow redistributors and the curved vortex generators will present a better heat transfer performance depends on the size of the curved vortex generators. As for the studied two sizes of vortex generators, the heat transfer performance is promoted by the flow redistributors for the fin with larger size of vortex generators and the performance is suppressed by the flow redistributors for the fin with smaller vortex generators.

Control characteristics for wrap-around fins on cruise missiles configurations

NASA Technical Reports Server (NTRS)

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.

Film Condensation of Steam on Externally Finned Horizontal Tubes.

DTIC Science & Technology

1985-03-01

Thermal Conductivity of Tube/Fin Metal i" ir - Condensation Rate Nu - Nusselt Number PA’ PB’ PC - Pressure at Points A, B, and C in Figure 2.1 APAB’ PcB...single finned tubes. To predict the film coefficients, they started with the Nusselt equations for condensation on a horizontal tube and on a vertical... Nusselt equation was obtained. A " condensation efficiency" was then proposed to account for a variable fin temperature, and was defined as: C, F1 (2.18) 3

Pectoral fin contact as a mechanism for social bonding among dolphins

USGS Publications Warehouse

Dudzinski, Kathleen; Ribic, Christine

2017-01-01

Bottlenose dolphins are large-brained social mammals residing in a fission-fusion society with relationships that are established and maintained over decades. We examined a decade-long data set of inter-individual pectoral fin contact exchanges to better understand how dolphins share information via tactile contact. Sex and age are significant factors in pectoral fin contact within non-kin dolphin dyads. Adult females shared more pectoral fin contacts with other adult females, while younger females showed no pattern of contact. Males shared more pectoral fin contacts with other males as juveniles and as adults, but showed no difference in the number of touches versus rubs as pectoral fin contacts with other males. Whether in the role of initiator as rubber or initiator as rubbee, male dolphins again preferred other males. These results support the notion that dolphins, especially male dolphins, might use pectoral fin contact as one tool in their repertoire for social bonding to establish, maintain and manage their inter-individual relationships. Additionally, it is also likely that the exchange of pectoral fin contact is developed and refined as individuals age, mature socially, and establish their place within a fission-fusion society.

Options for Hardening FinFETS with Flowable Oxide Between Fins

DTIC Science & Technology

2017-03-01

thus hardening by process is needed. Using the methodology of CV measurements on inexpensive experimental blanket oxides we have determined options...NY 10598 Abstract: A methodology using radiation-induced charge measurements by CV techniques on blanket oxides is shown to aid in the choice...of process options for hardening FinFETs. Net positive charge in flowable oxides was reduced by 50 % using a simple non -intrusive process change

Fgf16 is essential for pectoral fin bud formation in zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nomura, Ryohei; Kamei, Eriko; Hotta, Yuuhei

2006-08-18

Zebrafish pectoral fin bud formation is an excellent model for studying morphogenesis. Fibroblast growth factors (Fgfs) and sonic hedgehog (shh) are essential for pectoral fin bud formation. We found that Fgf16 was expressed in the apical ectodermal ridge (AER) of fin buds. A knockdown of Fgf16 function resulted in no fin bud outgrowth. Fgf16 is required for cell proliferation and differentiation in the mesenchyme and the AER of the fin buds, respectively. Fgf16 functions downstream of Fgf10, a mesenchymal factor, signaling to induce the expression of Fgf4 and Fgf8 in the AER. Fgf16 in the AER and shh in themore » zone of polarizing activity (ZPA) interact to induce and/or maintain each other's expression. These findings have revealed that Fgf16, a newly identified AER factor, plays a crucial role in pectoral fin bud outgrowth by mediating the interactions of AER-mesenchyme and AER-ZPA.« less

Mechanism of tonal noise generation from circular cylinder with spiral fin

NASA Astrophysics Data System (ADS)

Yamashita, Ryo; Hayashi, Hidechito; Okumura, Tetsuya; Hamakawa, Hiromitsu

2014-12-01

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.

Ontogenetic scaling of caudal fin shape in Squalus acanthias (Chondrichthyes, Elasmobranchii): a geometric morphometric analysis with implications for caudal fin functional morphology.

PubMed

Reiss, Katie L; Bonnan, Matthew F

2010-07-01

The shark heterocercal caudal fin and its contribution to locomotion are of interest to biologists and paleontologists. Current hydrodynamic data show that the stiff dorsal lobe leads the ventral lobe, both lobes of the tail are synchronized during propulsion, and tail shape reflects its overall locomotor function. Given the difficulties surrounding the analysis of shark caudal fins in vivo, little is known about changes in tail shape related to ontogeny and sex in sharks. A quantifiable analysis of caudal fin shape may provide an acceptable proxy for inferring gross functional morphology where direct testing is difficult or impossible. We examined ontogenetic and sex-related shape changes in the caudal fins of 115 Squalus acanthias museum specimens, to test the hypothesis that significant shape changes in the caudal fin shape occur with increasing size and between the sexes. Using linear and geometric morphometrics, we examined caudal shape changes within the context of current hydrodynamic models. We found no statistically significant linear or shape difference between sexes, and near-isometric scaling trends for caudal dimensions. These results suggest that lift and thrust increase linearly with size and caudal span. Thin-plate splines results showed a significant allometric shape change associated with size and caudal span: the dorsal lobe elongates and narrows, whereas the ventral lobe broadens and expands ventrally. Our data suggest a combination of caudal fin morphology with other body morphology aspects, would refine, and better elucidate the hydrodynamic factors (if any) that underlie the significant shape changes we report here for S. acanthias.

Fin Buffeting Features of an Early F-22 Model

NASA Technical Reports Server (NTRS)

Moses, Robert W.; Huttsell, Lawrence

2000-01-01

Fin buffeting is an aeroelastic phenomenon encountered by high performance aircraft, especially those with twin vertical tails that must operate at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. To date, the buffet (unsteady pressures) and buffeting (structural response) characteristics of the F-15 and F/A-18 fins have been studied extensively using flow visualization, flow velocity measurements, pressure transducers, and response gages. By means of windtunnel and flight tests of the F-15 and F/A-18, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can he increased by structural enhancements to these airframes. However, prior to the present research, data was not available outside the F-22 program regarding fin buffeting on the F-22 configuration. During a test in the Langley Transonic Dynamics Tunnel, flow visualization and unsteady fin surface pressures were recorded for a 13.3%-scale F-22 model at high angles of attack for the purpose of comparing with results available for similar aircraft configurations. Details of this test and fin buffeting are presented herein.

Functional analysis of limb enhancers in the developing fin

PubMed Central

Booker, Betty M.; Murphy, Karl K.

2013-01-01

Despite diverging ~365 million years ago, tetrapod limbs and pectoral fins express similar genes that could be regulated by shared regulatory elements. In this study, we set out to analyze the ability of enhancers to maintain tissue specificity in these two divergent structures. We tested 22 human sequences that were previously reported as mouse limb enhancers for their enhancer activity in zebrafish (Danio rerio). Using a zebrafish enhancer assay, we found that 10/22 (45 %) were positive for pectoral fin activity. Analysis of the various criteria that correlated with positive fin activity found that both spatial limb activity and evolutionary conservation are not good predictors of fin enhancer activity. These results suggest that zebrafish enhancer assays may be limited in detecting human limb enhancers, and this limitation does not improve by the use of limb spatial expression or evolutionary conservation. PMID:24068387

Flow-structure Interaction Modeling of a Fish Caudal Fin during Steady Swimming

NASA Astrophysics Data System (ADS)

Liu, Geng; Geng, Biao; Zheng, Xudong; Xue, Qian; Dong, Haibo

2017-11-01

It's widely thought that the flexibilities of fish fins play critical roles in propulsive performance enhancement (such as thrust augment and efficiency improvement) in nature. In order to explore the formation mechanisms of the fish fin's flexible morphing and its hydrodynamic benefits as well, a high-fidelity flow-structure/membrane interaction modeling of the fish caudal fin is conducted in this work. Following the realistic configuration of the fish caudal fin, a thin membrane supported by a series of beams is constructed. The material properties of the membrane and the beams are reversely determined by the realistic fin morphing obtained from the high-speed videos and the high fidelity flow-structure interaction simulations. With the accurate material property, we investigate the interplay between structure, kinematics and fluid flow in caudal fin propulsion. Detailed analyses on the relationship between the flexural stiffness, fin morphing patterns, hydrodynamic forces and vortex dynamics are then conducted.

Large Scale Density Estimation of Blue and Fin Whales (LSD)

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...sensors, or both. The goal of this research is to develop and implement a new method for estimating blue and fin whale density that is effective over...develop and implement a density estimation methodology for quantifying blue and fin whale abundance from passive acoustic data recorded on sparse

The incidence of bent dorsal fins in free-ranging cetaceans.

PubMed

Alves, F; Towers, J R; Baird, R W; Bearzi, G; Bonizzoni, S; Ferreira, R; Halicka, Z; Alessandrini, A; Kopelman, A H; Yzoard, C; Rasmussen, M H; Bertulli, C G; Jourdain, E; Gullan, A; Rocha, D; Hupman, K; Mrusczok, M-T; Samarra, F I P; Magalhães, S; Weir, C R; Ford, J K B; Dinis, A

2018-02-01

Laterally bent dorsal fins are rarely observed in free-ranging populations of cetaceans, contrary to captivity, where most killer whale Orcinus orca adult males have laterally collapsed fins. This topic has been poorly explored, and data/information on its occurrence and possible causes are limited. The present study: (i) undertakes a review of the available information on bent dorsal fins in free-ranging cetaceans, and updates it with new records, (ii) reports on the proportion of bent fins in different study populations, and (iii) discusses possible causes. An empirical approach based on bibliographic research and compilation of 52 new records collected worldwide resulted in a total of 17 species of cetaceans displaying bent dorsal fins. The species with the highest number of records (64%) and from most locations was O. orca. On average, individuals with bent dorsal fins represent < 1% of their populations, with the exception of false killer whales Pseudorca crassidens and O. orca. While line injuries associated with fisheries interactions may be the main cause for P. crassidens, and the vulnerability to health issues caused by the evolutionary enlargement of the fin may be the cause for O. orca adult males, factors contributing to this abnormality for other species are still unclear. The occurrence of bent dorsals could be influenced by a set of variables rather than by a single factor but, irrespective of the cause, it is suggested that it does not directly affect the animals' survivorship. While still rare in nature, this incident is more common (at least 101 known cases) and widespread (geographically and in species diversity) than hypothesized, and is not confined only to animals in captive environments. Investigation into the occurrence of bent fins may be an interesting avenue of research. © 2017 Anatomical Society.

Hydrodynamic function of dorsal fins in spiny dogfish and bamboo sharks during steady swimming.

PubMed

Maia, Anabela; Lauder, George V; Wilga, Cheryl D

2017-11-01

A key feature of fish functional design is the presence of multiple fins that allow thrust vectoring and redirection of fluid momentum to contribute to both steady swimming and maneuvering. A number of previous studies have analyzed the function of dorsal fins in teleost fishes in this context, but the hydrodynamic function of dorsal fins in freely swimming sharks has not been analyzed, despite the potential for differential functional roles between the anterior and posterior dorsal fins. Previous anatomical research has suggested a primarily stabilizing role for shark dorsal fins. We evaluated the generality of this hypothesis by using time-resolved particle image velocimetry to record water flow patterns in the wake of both the anterior and posterior dorsal fins in two species of freely swimming sharks: bamboo sharks ( Chiloscyllium plagiosum ) and spiny dogfish ( Squalus acanthias ). Cross-correlation analysis of consecutive images was used to calculate stroke-averaged mean longitudinal and lateral velocity components, and vorticity. In spiny dogfish, we observed a velocity deficit in the wake of the first dorsal fin and flow acceleration behind the second dorsal fin, indicating that the first dorsal fin experiences net drag while the second dorsal fin can aid in propulsion. In contrast, the wake of both dorsal fins in bamboo sharks displayed increased net flow velocity in the majority of trials, reflecting a thrust contribution to steady swimming. In bamboo sharks, fluid flow in the wake of the second dorsal fin had higher absolute average velocity than that for first dorsal fin, and this may result from a positive vortex interaction between the first and second dorsal fins. These data suggest that the first dorsal fin in spiny dogfish has primarily a stabilizing function, while the second dorsal fin has a propulsive function. In bamboo sharks, both dorsal fins can contribute thrust and should be considered as propulsive adjuncts to the body during steady

Magnetoresistance measurement of permalloy thin film rings with triangular fins

NASA Astrophysics Data System (ADS)

Lai, Mei-Feng; Hsu, Chia-Jung; Liao, Chun-Neng; Chen, Ying-Jiun; Wei, Zung-Hang

2010-01-01

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.

The ethics of sin taxes.

PubMed

Green, Rebecca

2011-01-01

ABSTRACT The current global economic crisis is forcing governments to consider a variety of methods to generate funds for infrastructure. In the United States, smoking-related illness and an obesity epidemic are forcing public health institutions to consider a variety of methods to influence health behaviors of entire target groups. In this paper, the author uses a public health nursing model, the Public Health Code of Ethics (Public Health Leadership Society, 2002), the American Nurses' Association (ANA) Code of Ethics (2001), and other relevant ethical theory to weigh and balance the arguments for and against the use of sin taxes. A position advocating the limited use of sin taxes is supported as a reasonable stance for the public health professional. © 2010 Wiley Periodicals, Inc.

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

NASA Astrophysics Data System (ADS)

Pastuszko, Robert; Piasecka, Magdalena

2012-11-01

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).

Establishment of a biomimetic device based on tri-layer polymer actuators--propulsion fins.

PubMed

Alici, Gursel; Spinks, Geoffrey; Huynh, Nam N; Sarmadi, Laleh; Minato, Rick

2007-06-01

We propose to use bending type tri-layer polymer actuators as propulsion fins for a biomimetic device consisting of a rigid body, like a box fish having a carapace, and paired fins running through the rigid body, like a fish having pectoral fins. The fins or polymer bending actuators can be considered as individually controlled flexible membranes. Each fin is activated with sinusoidal inputs such that there is a phase lag between the movements of successive fins to create enough thrust force for propulsion. Eight fins with 0.125 aspect ratio have been used along both sides of the rigid body to move the device in the direction perpendicular to the longitudinal axis of the body. The designed device with the paired fins was successfully tested, moving in an organic solution consisting of solvent, propylene carbonate (PC), and electrolyte. The design procedure outlined in this study is offered as a guide to making functional devices based on polymer actuators and sensors.

Differential induction of four msx homeobox genes during fin development and regeneration in zebrafish.

PubMed

Akimenko, M A; Johnson, S L; Westerfield, M; Ekker, M

1995-02-01

To study the genetic regulation of growth control and pattern formation during fin development and regeneration, we have analysed the expression of four homeobox genes, msxA, msxB, msxC and msxD in zebrafish fins. The median fin fold, which gives rise to the unpaired fins, expresses these four msx genes during development. Transcripts of the genes are also present in cells of the presumptive pectoral fin buds. The most distal cells, the apical ectodermal ridge of the paired fins and the cleft and flanking cells of the median fin fold express all these msx genes with the exception of msxC. Mesenchymal cells underlying the most distal cells express all four genes. Expression of the msx genes in the fin fold and fin buds is transient and, by 3 days after fertilization, msx expression in the median fin fold falls below levels detectable by in situ hybridization. Although the fins of adult zebrafish normally have levels of msx transcripts undetectable by in situ hybridization, expression of all four genes is strongly reinduced during regeneration of both paired and unpaired fins. Induction of msx gene expression in regenerating caudal fins occurs as early as 30 hours postamputation. As the blastema forms, the levels of expression increase and reach a maximum between the third and fifth days. Then, msx expression progressively declines and disappears by day 12 when the caudal fin has grown back to its normal size. In the regenerating fin, the blastema cells that develop at the tip of each fin ray express msxB and msxC. Cells of the overlying epithelium express msxA and msxD, but do not express msxB or msxC. Amputations at various levels along the proximodistal axis of the fin suggest that msxB expression depends upon the position of the blastema, with cells of the rapidly proliferating proximal blastema expressing higher levels than the cells of the less rapidly proliferating distal blastema. Expression of msxC and msxD is independent of the position of the blastema cell

Original antigenic sin responses to influenza viruses.

PubMed

Kim, Jin Hyang; Skountzou, Ioanna; Compans, Richard; Jacob, Joshy

2009-09-01

Most immune responses follow Burnet's rule in that Ag recruits specific lymphocytes from a large repertoire and induces them to proliferate and differentiate into effector cells. However, the phenomenon of "original antigenic sin" stands out as a paradox to Burnet's rule of B cell engagement. Humans, upon infection with a novel influenza strain, produce Abs against older viral strains at the expense of responses to novel, protective antigenic determinants. This exacerbates the severity of the current infection. This blind spot of the immune system and the redirection of responses to the "original Ag" rather than to novel epitopes were described fifty years ago. Recent reports have questioned the existence of this phenomenon. Hence, we revisited this issue to determine the extent to which original antigenic sin is induced by variant influenza viruses. Using two related strains of influenza A virus, we show that original antigenic sin leads to a significant decrease in development of protective immunity and recall responses to the second virus. In addition, we show that sequential infection of mice with two live influenza virus strains leads to almost exclusive Ab responses to the first viral strain, suggesting that original antigenic sin could be a potential strategy by which variant influenza viruses subvert the immune system.

Gene expression profiles of fin regeneration in loach (Paramisgurnus dabryanu).

PubMed

Li, Li; He, Jingya; Wang, Linlin; Chen, Weihua; Chang, Zhongjie

2017-11-01

Teleost fins can regenerate accurate position-matched structure and function after amputation. However, we still lack systematic transcriptional profiling and methodologies to understand the molecular basis of fin regeneration. After histological analysis, we established a suppression subtraction hybridization library containing 418 distinct sequences expressed differentially during the process of blastema formation and differentiation in caudal fin regeneration. Genome ontology and comparative analysis of differential distribution of our data and the reference zebrafish genome showed notable subcategories, including multi-organism processes, response to stimuli, extracellular matrix, antioxidant activity, and cell junction function. KEGG pathway analysis allowed the effective identification of relevant genes in those pathways involved in tissue morphogenesis and regeneration, including tight junction, cell adhesion molecules, mTOR and Jak-STAT signaling pathway. From relevant function subcategories and signaling pathways, 78 clones were examined for further Southern-blot hybridization. Then, 17 genes were chosen and characterized using semi-quantitative PCR. Then 4 candidate genes were identified, including F11r, Mmp9, Agr2 and one without a match to any database. After real-time quantitative PCR, the results showed obvious expression changes in different periods of caudal fin regeneration. We can assume that the 4 candidates, likely valuable genes associated with fin regeneration, deserve additional attention. Thus, our study demonstrated how to investigate the transcript profiles with an emphasis on bioinformatics intervention and how to identify potential genes related to fin regeneration processes. The results also provide a foundation or knowledge for further research into genes and molecular mechanisms of fin regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance Analysis of a Self-Propelling Flat Plate Fin with Joint Compliance

NASA Astrophysics Data System (ADS)

Reddy, N. Srinivasa; Sen, Soumen; Pal, Sumit; Shome, Sankar Nath

2017-12-01

Fish fin muscles are compliant and they regulate the stiffness to suit different swimming conditions. This article attempts to understand the significance of presence of compliance in fin muscle with help of a flexible joint flat plate fin model. Blade element method is employed to model hydrodynamics and to compute the forces of interaction during motion of the plate within fluid. The dynamic model of self-propelling fin is developed through multi-body dynamics approach considering the hydrodynamic forces as external forces acting on the fin. The derived hydrodynamic model is validated with experiments on rigid flat plate fin. The effect of the joint stiffness and flapping frequency on the propulsion speed and efficiency is investigated through simulations using the derived and validated model. The propulsion efficiency is found to be highly influenced by the joint stiffness at a given flapping frequency. The fin attained maximum propulsion efficiency when the joint stiffness is tuned to a value at which flapping frequency matches near natural frequency of the fin. At this tuned joint stiffness and flapping frequency, the resulted Strouhal numbers are observed to fall within the optimum range (0.2 to 0.4) for maximized propulsion efficiency of flying birds and swimming aquatic animals reported in literature.

Analog and RF performance of a multigate FinFET at nano scale

NASA Astrophysics Data System (ADS)

Kumar, Abhishek

2016-12-01

In this paper, analog and RF performance of the Fin field effect transistor (FET) at Nano scale is observed through 3D simulation. FinFET devices like rectangular gate all around (RE-GAA) FinFET, cylindrical gate all around (CY-GAA) FinFET and triple gate (TG) FinFET are observed. The figure of merit (FOMs) such as input-output characteristics, trans-conductance (gm), output-conductance (gd), intrinsic gain (gm/gd), gate capacitance (gate to source and total gate capacitance), unity gain cut-off frequency (ft), trans-conductance generation factor (TGF), gain frequency product (GFP), gain bandwidth product (GBP) and gain transconductance frequency product (GTFP) are observed. The analog performance of a FinFETs are observed by realising source follower circuit with NMOS transistor as a current source. The source follower circuit gain is observed. It has been observed that maximum capacitance is observed in case gate all around condition. Rectangular gate all around has the highest transconductance. In the source follower circuit, the gain curve (Vout/Vin) is sharper for TG-FinFET.

The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages.

PubMed

Stewart, Thomas A; Smith, W Leo; Coates, Michael I

2014-04-22

Adipose fins are appendages found on the dorsal midline between the dorsal and caudal fins in more than 6000 living species of teleost fishes. It has been consistently argued that adipose fins evolved once and have been lost repeatedly across teleosts owing to limited function. Here, we demonstrate that adipose fins originated repeatedly by using phylogenetic and anatomical evidence. This suggests that adipose fins are adaptive, although their function remains undetermined. To test for generalities in the evolution of form in de novo vertebrate fins, we studied the skeletal anatomy of adipose fins across 620 species belonging to 186 genera and 55 families. Adipose fins have repeatedly evolved endoskeletal plates, anterior dermal spines and fin rays. The repeated evolution of fin rays in adipose fins suggests that these fins can evolve new tissue types and increased structural complexity by expressing fin-associated developmental modules in these new territories. Patterns of skeletal elaboration differ between the various occurrences of adipose fins and challenge prevailing hypotheses for vertebrate fin origin. Adipose fins represent a powerful and, thus far, barely studied model for exploring the evolution of vertebrate limbs and the roles of adaptation and generative biases in morphological evolution.

The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages

PubMed Central

Stewart, Thomas A.; Smith, W. Leo; Coates, Michael I.

2014-01-01

Adipose fins are appendages found on the dorsal midline between the dorsal and caudal fins in more than 6000 living species of teleost fishes. It has been consistently argued that adipose fins evolved once and have been lost repeatedly across teleosts owing to limited function. Here, we demonstrate that adipose fins originated repeatedly by using phylogenetic and anatomical evidence. This suggests that adipose fins are adaptive, although their function remains undetermined. To test for generalities in the evolution of form in de novo vertebrate fins, we studied the skeletal anatomy of adipose fins across 620 species belonging to 186 genera and 55 families. Adipose fins have repeatedly evolved endoskeletal plates, anterior dermal spines and fin rays. The repeated evolution of fin rays in adipose fins suggests that these fins can evolve new tissue types and increased structural complexity by expressing fin-associated developmental modules in these new territories. Patterns of skeletal elaboration differ between the various occurrences of adipose fins and challenge prevailing hypotheses for vertebrate fin origin. Adipose fins represent a powerful and, thus far, barely studied model for exploring the evolution of vertebrate limbs and the roles of adaptation and generative biases in morphological evolution. PMID:24598422

Propulsion of a fin whale (Balaenoptera physalus): why the fin whale is a fast swimmer.

PubMed

Bose, N; Lien, J

1989-07-22

Measurements of an immature fin whale (Balaenoptera physalus), which died as a result of entrapment in fishing gear near Frenchmans Cove, Newfoundland (47 degrees 9' N, 55 degrees 25' W), were made to obtain estimates of volume and surface area of the animal. Detailed measurements of the flukes, both planform and sections, were also obtained. A strip theory was developed to calculate the hydrodynamic performance of the whale's flukes as an oscillating propeller. This method is based on linear, two-dimensional, small-amplitude, unsteady hydrofoil theory with correction factors used to account for the effects of finite span and finite amplitude motion. These correction factors were developed from theoretical results of large-amplitude heaving motion and unsteady lifting-surface theory. A model that makes an estimate of the effects of viscous flow on propeller performance was superimposed on the potential-flow results. This model estimates the drag of the hydrofoil sections by assuming that the drag is similar to that of a hydrofoil section in steady flow. The performance characteristics of the flukes of the fin whale were estimated by using this method. The effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized. Frictional effects in particular were found to reduce the hydrodynamic efficiency of the flukes significantly. The results are discussed and compared with the known characteristics of fin-whale swimming.

Optimization of geometric parameters of heat exchange pipes pin finning

NASA Astrophysics Data System (ADS)

Akulov, K. A.; Golik, V. V.; Voronin, K. S.; Zakirzakov, A. G.

2018-05-01

The work is devoted to optimization of geometric parameters of the pin finning of heat-exchanging pipes. Pin fins were considered from the point of view of mechanics of a deformed solid body as overhang beams with a uniformly distributed load. It was found out under what geometric parameters of the nib (diameter and length); the stresses in it from the influence of the washer fluid will not exceed the yield strength of the material (aluminum). Optimal values of the geometric parameters of nibs were obtained for different velocities of the medium washed by them. As a flow medium, water and air were chosen, and the cross section of the nibs was round and square. Pin finning turned out to be more than 3 times more compact than circumferential finning, so its use makes it possible to increase the number of fins per meter of the heat-exchanging pipe. And it is well-known that this is the main method for increasing the heat transfer of a convective surface, giving them an indisputable advantage.

Ge-cap quantum-well bulk FinFET for 5 nm node CMOS integration

NASA Astrophysics Data System (ADS)

Dwi Kurniawan, Erry; Peng, Kang-Hui; Yang, Shang-Yi; Yang, Yi-Yun; Thirunavukkarasu, Vasanthan; Lin, Yu-Hsien; Wu, Yung-Chun

2018-04-01

We propose the use of Ge-cap quantum-well (QW) bulk FinFET for 5 nm CMOS integration, which is a Si channel wrapped with Ge around three sides of the fin channel. The simulation results show that the Ge-cap FinFET structure demonstrates better performance than pure Si, pure Ge, and Si-cap FinFET structures. By optimizing Si fin width and Ge-cap thickness, the on-state current of nFET and pFET can also be symmetric without changing the total fin width (F Wp = F Wn). The electrons in Ge-cap nFinFET concentrate in the Si channel because of QWs formed in the lowest conduction band of the Ge and Si heterostructure, while the holes in Ge-cap pFinFET prefer to stay in Ge surfaces owing to QWs formed in the Ge valence band. The physics studies of this device have made the design rules relevant for the application of the CMOS inverter and static random access memory (SRAM) application technology.

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

NASA Astrophysics Data System (ADS)

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.

Fin field effect transistor directionality impacts printing of implantation shapes

NASA Astrophysics Data System (ADS)

Wang, Xiren; Granik, Yuri

2018-01-01

In modern integrated circuit (IC) fabrication processes, the photoresist receives considerable illumination energy that is reflected by underlying topography during optical lithography of implantation layers. Bottom antireflective coating (BARC) is helpful to mitigate the reflection. Often, however, BARC is not used, because its removal is technically challenging, in addition to its relatively high economic cost. Furthermore, the advanced technology nodes, such as 14/10-nm nodes, have introduced fin field effect transistor (FinFET), which makes reflection from nonuniform silicon substrates exceptionally complicated. Therefore, modeling reflection from topography becomes obligatory to accurately predict printing of implantation shapes. Typically, FinFET is always fixed in one direction in realistic designs. However, the same implantation rectangle may be oriented in either horizontal or vertical direction. Then, there are two types of relations between the critical dimension (CD) and FinFET, namely a parallel-to and a perpendicular-to relation. We examine the fin directionality impact on CD. We found that this impact may be considerable in some cases. We use our in-house rigorous optical topography simulator to reveal underlining physical reasons. One of the major causes of the CD differences is that in the parallel orientation, the solid sidewalls of the fins conduct considerable light reflections unlike for the perpendicular orientation. This finding can aid the compact modeling in optical proximity correction of implantation masks.

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

NASA Astrophysics Data System (ADS)

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.

Wind Tunnel Investigation of Fuselage Stability in Yaw with Various Arrangements of Fins

NASA Technical Reports Server (NTRS)

Hoggard, H Page, Jr

1940-01-01

An investigation was made in the 7-by-10 foot wind tunnel to determine the effects of dorsal-type fins and various arrangements of fins on the aerodynamic characteristics of a streamline circular fuselage. Comparative plots of the aerodynamic characteristics of the fuselage alone and the fuselage with various fin arrangements are given to show their effects on coefficients of yawing moment, drag, and lateral force. Results are also given for one case in which a rear fin on a circular fuselage was faired with modeling clay to obtain a fuselage shape with the same side elevation as the fuselage with the unfaired fin but with an elliptical cross section over the rearward portion of the fuselage. The results indicated that fin area to the rear of the center of gravity of the fuselage was beneficial in reducing the magnitude of the unstable yawing moments at large angles of yaw; whereas, fin area forward of the center of gravity was harmful. The dorsal-type fin was more effective for increasing the yawing stability of the fuselage than was a smoothly faired rearward portion with the same side elevation as the fuselage with the unfaired dorsal type fin. The minimum drag coefficient and the slope of the curve of yawing-moment coefficient of the fuselage at zero yaw were unaffected by the addition of the fins, within the experimental accuracy of the tests.

Fin degeneration of young-of-the-year Alosa pseudoharengus (Clupeidae) in southern Lake Michigan

USGS Publications Warehouse

Brown, Edward H.; Norden, Carroll R.

1970-01-01

Young-of-the-year alewives, Alosa pseudoharengus, with extremely shortened caudal fins were observed at four locations in southern Lake Michigan between 1964 and 1968. Some of the fins appeared stunted or underdeveloped, but microscopic examination revealed a deterioration of the fins and not an ontogenetic abnormality. Deterioration of the caudal fin was frequently accompanied by degeneration of the dorsal and anal fins. Degenerate fins were not found on other species nor on older alewives, with the exception of one known yearling alewife at Waukegan and possibly a few of the larger fish at Milwaukee.

Age estimation of burbot using pectoral fin rays, brachiostegal rays, and otoliths

USGS Publications Warehouse

Klein, Zachary B.; Terrazas, Marc M.; Quist, Michael C.

2014-01-01

Throughout much of its native distribution, burbot (Lota lota) is a species of conservation concern. Understanding dynamic rate functions is critical for the effective management of sensitive burbot populations, which necessitates accurate and precise age estimates. Managing sensitive burbot populations requires an accurate and precise non-lethal alternative. In an effort to identify a non-lethal ageing structure, we compared the precision of age estimates obtained from otoliths, pectoral fin rays, dorsal fin rays and branchiostegal rays from 208 burbot collected from the Green River drainage, Wyoming. Additionally, we compared the accuracy of age estimates from pectoral fin rays, dorsal fin rays and branchiostegal rays to those of otoliths. Dorsal fin rays were immediately deemed a poor ageing structure and removed from further analysis. Age-bias plots of consensus ages derived from branchiostegal rays and pectoral fin rays were appreciably different from those obtained from otoliths. Exact agreement between readers and reader confidence was highest for otoliths and lowest for branchiostegal rays. Age-bias plots indicated that age estimates obtained from branchiostegal rays and pectoral fin rays were substantially different from age estimates obtained from otoliths. Our results indicate that otoliths provide the most precise age estimates for burbot.

Inhibition of polyomavirus ori-dependent DNA replication by mSin3B.

PubMed

Xie, An-Yong; Folk, William R

2002-12-01

When tethered in cis to DNA, the transcriptional corepressor mSin3B inhibits polyomavirus (Py) ori-dependent DNA replication in vivo. Histone deacetylases (HDACs) appear not to be involved, since tethering class I and class II HDACs in cis does not inhibit replication and treating the cells with trichostatin A does not specifically relieve inhibition by mSin3B. However, the mSin3B L59P mutation that impairs mSin3B interaction with N-CoR/SMRT abrogates inhibition of replication, suggesting the involvement of N-CoR/SMRT. Py large T antigen interacts with mSin3B, suggesting an HDAC-independent mechanism by which mSin3B inhibits DNA replication.

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

NASA Astrophysics Data System (ADS)

Palmre, Viljar; Hubbard, Joel J.; Fleming, Maxwell; Pugal, David; Kim, Sungjun; Kim, Kwang J.; Leang, Kam K.

2013-01-01

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

Natural convection and radiation heat transfer from an array of inclined pin fins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alessio, M.E.; Kaminski, D.A.

1989-02-01

Natural convection and radiation from an air-cooled, highly populated pin-fin array were studied experimentally. the effects of pin density, pin length, and the angle of the pin to the horizontal were measured. Previous work by Sparrow and Vemuri treated the case of a vertical base plate with horizontal fins. recently, Sparrow and Vemuri (1986) extended their study to include results for vertical fins with a horizontal down-facing base plate, as well as vertical fins with a horizontal up-facing base plate. In this study, the base plate is maintained in a vertical position and the angle of the pins is variedmore » from the horizontal. The main intent of this study was to compare the performance of inclined pin fins with straight pin fins. In all cases studied, the straight, horizontal fins were superior to the inclined fins. It was possible to obtain a single general correlation of the test data. While this correlation is recommended within the range of parameters that were tested here, one significant parameter, the size of the base plate, was not varied.« less

Senescence-associated SIN3B promotes inflammation and pancreatic cancer progression

PubMed Central

Rielland, Maïté; Cantor, David J.; Graveline, Richard; Hajdu, Cristina; Mara, Lisa; de Diego Diaz, Beatriz; Miller, George; David, Gregory

2014-01-01

Pancreatic ductal adenocarcinoma (PDAC) is strikingly resistant to conventional therapeutic approaches. We previously demonstrated that the histone deacetylase–associated protein SIN3B is essential for oncogene-induced senescence in cultured cells. Here, using a mouse model of pancreatic cancer, we have demonstrated that SIN3B is required for activated KRAS-induced senescence in vivo. Surprisingly, impaired senescence as the result of genetic inactivation of Sin3B was associated with delayed PDAC progression and correlated with an impaired inflammatory response. In murine and human pancreatic cells and tissues, levels of SIN3B correlated with KRAS-induced production of IL-1α. Furthermore, evaluation of human pancreatic tissue and cancer cells revealed that Sin3B was decreased in control and PDAC samples, compared with samples from patients with pancreatic inflammation. These results indicate that senescence-associated inflammation positively correlates with PDAC progression and suggest that SIN3B has potential as a therapeutic target for inhibiting inflammation-driven tumorigenesis. PMID:24691445

Inhibition of caudal fin regeneration in Corydoras aeneus by lithium chloride.

PubMed

Zarnescu, Otilia; Stavri, Simona; Moldovan, Lucia

2013-03-01

In the present study we examined the effects of lithium chloride on the Corydoras aeneus caudal fin regeneration. After caudal fin amputation, the fish were exposed 3h daily to 35 mM lithium chloride for 9 days. The effects of lithium chloride treatment were evaluated by analyzing the caudal fin structure at 3, 6 and 9 days after amputation. Comparison of normal and LiCl treated fish clearly shows that regeneration of amputated caudal fins was inhibited or delayed after lithium treatment. By the third day after amputation (dpa) either no epidermal cap or blastema ever formed or the epidermal cap had an abnormal morphology in lithium treated fish. By the 3 and 6 dpa no lepidotrichial matrix deposition was observed in the lithium treated fish compared to control fish. Unlike the control fish that completely regenerate their caudal fins after 9 dpa and have fully mineralized lepidotrichia, lithium treated fish have small blastema. In some treated fish, small amounts of new lepidotrichial matrix were observed at this time, in some fin rays. Ultrastructural observations have shown differences between control and lithium treated fish. Thus, in the lithium treated fish we observed expanded intercellular spaces between epidermal cells and many apoptotic cells. Results of this study suggest the use of this model in elucidating the molecular mechanisms that are responsible for regeneration of complex structures such as fish fins. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

Thermoelectric generator with hinged assembly for fins

DOEpatents

Purdy, David L.; Shapiro, Zalman M.; Hursen, Thomas F.; Maurer, Gerould W.

1976-11-02

A cylindrical casing has a central shielded capsule of radioisotope fuel. A plurality of thermonuclear modules are axially arranged with their hot junctions resiliently pressed toward the shield and with their cold junctions adjacent a transition member having fins radiating heat to the environment. For each module, the assembly of transition member and fins is hinged to the casing for swinging to permit access to and removal of such module. A ceramic plate having gold layers on opposite faces prevents diffusion bonding of the hot junction to the shield.

Resolution of ray-finned fish phylogeny and timing of diversification.

PubMed

Near, Thomas J; Eytan, Ron I; Dornburg, Alex; Kuhn, Kristen L; Moore, Jon A; Davis, Matthew P; Wainwright, Peter C; Friedman, Matt; Smith, W Leo

2012-08-21

Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the "bush at the top of the tree" that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the "Second Age of Fishes."

Dynamics of zebrafish fin regeneration using a pulsed SILAC approach.

PubMed

Nolte, Hendrik; Hölper, Soraya; Housley, Michael P; Islam, Shariful; Piller, Tanja; Konzer, Anne; Stainier, Didier Y R; Braun, Thomas; Krüger, Marcus

2015-02-01

The zebrafish owns remarkable regenerative capacities allowing regeneration of several tissues, including the heart, liver, and brain. To identify protein dynamics during fin regeneration we used a pulsed SILAC approach that enabled us to detect the incorporation of (13) C6 -lysine (Lys6) into newly synthesized proteins. Samples were taken at four different time points from noninjured and regrowing fins and incorporation rates were monitored using a combination of single-shot 4-h gradients and high-resolution tandem MS. We identified more than 5000 labeled proteins during the first 3 weeks of fin regeneration and were able to monitor proteins that are responsible for initializing and restoring the shape of these appendages. The comparison of Lys6 incorporation rates between noninjured and regrowing fins enabled us to identify proteins that are directly involved in regeneration. For example, we observed increased incorporation rates of two actinodin family members at the actinotrichia, which is a hairlike fiber structure at the tip of regrowing fins. Moreover, we used quantitative real-time RNA measurements of several candidate genes, including osteoglycin, si:ch211-288h17.3, and prostaglandin reductase 1 to correlate the mRNA expression to Lys6 incorporation data. This novel pulsed SILAC methodology in fish can be used as a versatile tool to monitor newly synthesized proteins and will help to characterize protein dynamics during regenerative processes in zebrafish beyond fin regeneration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Harnessing Active Fins to Segregate Nanoparticles from Binary Mixtures

NASA Astrophysics Data System (ADS)

Liu, Ya; Kuksenok, Olga; Bhattacharya, Amitabh; Ma, Yongting; He, Ximin; Aizenberg, Joanna; Balazs, Anna

2014-03-01

One of the challenges in creating high-performance polymeric nanocomposites for optoelectronic applications, such as bilayer solar cells, is establishing effective and facile routes for controlling the properties of interface and segregation of binary particles with hole conductor particles and electron conductor particles. We model nanocomposites that encompass binary particles and binary blends in a microchannel. An array of oscillating microfins is immersed in the fluid and tethered to the floor of the microchannel; the fluid containing mixture of nanoparticles is driven along the channel by an imposed pressure gradient. During the oscillations, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely within the lower stream when they are tilted. We introduce specific interaction between the fins and particulates in the solution. Fins can selectively ``catch'' target nanoparticles within the upper fluid stream and then release them into the lower stream. We focus on different modes of fins motion to optimize selective segregation of particles within binary mixture. Our approach provides an effective means of tailoring the properties and ultimate performance of the composites.

Large Scale Density Estimation of Blue and Fin Whales: Utilizing Sparse Array Data to Develop and Implement a New Method for Estimating Blue and Fin Whale Density

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...Utilizing Sparse Array Data to Develop and Implement a New Method for Estimating Blue and Fin Whale Density Len Thomas & Danielle Harris Centre...to develop and implement a new method for estimating blue and fin whale density that is effective over large spatial scales and is designed to cope

A shift in anterior–posterior positional information underlies the fin-to-limb evolution

PubMed Central

Onimaru, Koh; Kuraku, Shigehiro; Takagi, Wataru; Hyodo, Susumu; Sharpe, James; Tanaka, Mikiko

2015-01-01

The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior–posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network. DOI: http://dx.doi.org/10.7554/eLife.07048.001 PMID:26283004

Optimization design of LED heat dissipation structure based on strip fins

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Wan, Wenbin; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

To solve the heat dissipation problem of LED, a radiator structure based on strip fins is designed and the method to optimize the structure parameters of strip fins is proposed in this paper. The combination of RBF neural networks and particle swarm optimization (PSO) algorithm is used for modeling and optimization respectively. During the experiment, the 150 datasets of LED junction temperature when structure parameters of number of strip fins, length, width and height of the fins have different values are obtained by ANSYS software. Then RBF neural network is applied to build the non-linear regression model and the parameters optimization of structure based on particle swarm optimization algorithm is performed with this model. The experimental results show that the lowest LED junction temperature reaches 43.88 degrees when the number of hidden layer nodes in RBF neural network is 10, the two learning factors in particle swarm optimization algorithm are 0.5, 0.5 respectively, the inertia factor is 1 and the maximum number of iterations is 100, and now the number of fins is 64, the distribution structure is 8*8, and the length, width and height of fins are 4.3mm, 4.48mm and 55.3mm respectively. To compare the modeling and optimization results, LED junction temperature at the optimized structure parameters was simulated and the result is 43.592°C which approximately equals to the optimal result. Compared with the ordinary plate-fin-type radiator structure whose temperature is 56.38°C, the structure greatly enhances heat dissipation performance of the structure.

Resolution of ray-finned fish phylogeny and timing of diversification

PubMed Central

Near, Thomas J.; Eytan, Ron I.; Dornburg, Alex; Kuhn, Kristen L.; Moore, Jon A.; Davis, Matthew P.; Wainwright, Peter C.; Friedman, Matt; Smith, W. Leo

2012-01-01

Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the “bush at the top of the tree” that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the “Second Age of Fishes.” PMID:22869754

Numerical modeling of a finned PCM heat sink

NASA Astrophysics Data System (ADS)

Kozak, Y.; Ziskind, G.

2012-09-01

Phase-change materials (PCMs) can absorb large amounts of heat without significant rise of their temperature during the melting process. This effect is attractive for using in thermal energy storage and passive thermal management. One of the techniques enhance the rate of heat transfer into PCMs is by using fins made of a thermally high conductive material. This paper deals with numerical modeling of a finned PCM-based heat sink. Heat is dissipated on the heat sink base and may be either absorbed by the PCM stored in compartments with conducting walls, or dissipated to the air using fins, or both. A detailed analysis had been done by means of a complete solution of the governing multi-dimensional conservation equations, taking into account convection in the melt, density and volume change due to phase change and temperature variation, motion of solid in the liquid, and other associated phenomena.

The evaluation of the rolling moments induced by wraparound fins

NASA Technical Reports Server (NTRS)

Seginer, A.; Bar-Haim, B.

1983-01-01

A possible reason is suggested for the induced rolling moments occurring on wraparound-fin configurations in subsonic flight at zero angle of attack. The subsonic potential flow over the configuration at zero incidence is solved numerically. The body is simulated by a distribution of sources along its axis, and the fins are described by a vortex-lattice method. It is shown that rolling moments can be induced on the antisymmetric fins by the radial flow generated at the base of the configuration, either over the converging separated wake, or over the diverging plume of a rocket motor.

Evolution of motor innervation to vertebrate fins and limbs.

PubMed

Murakami, Yasunori; Tanaka, Mikiko

2011-07-01

The evolution and diversification of vertebrate behaviors associated with locomotion depend highly on the functional transformation of paired appendages. Although the evolution of fins into limbs has long been a focus of interest to scientists, the evolution of neural control during this transition has not received much attention. Recent studies have provided significant progress in the understanding of the genetic and developmental bases of the evolution of fin/limb motor circuitry in vertebrates. Here we compare the organization of the motor neurons in the spinal cord of various vertebrates. We also discuss recent advances in our understanding of these events and how they can provide a mechanistic explanation for the evolution of fin/limb motor circuitry in vertebrates. Copyright © 2011 Elsevier Inc. All rights reserved.

Comparison of rainbow smelt age estimates from fin rays and otoliths

USGS Publications Warehouse

Walsh, M.G.; Maloy, A.P.; O'Brien, T. P.

2008-01-01

Rainbow smelt Osmerus mordax, although nonnative, are an important component of the offshore food web in the Laurentian Great Lakes. In Lake Ontario, we estimate ages of rainbow smelt annually to study population dynamics such as year-class strength and age-specific growth and mortality. Since the early 1980s, we have used pectoral fin rays to estimate rainbow smelt ages, but the sectioning and mounting of fin rays are time and labor intensive. Our objective was to assess the feasibility of using otoliths rather than fin rays to estimate rainbow smelt ages. Three readers interpreted the ages of 172 rainbow smelt (60-198 mm total length) based on thin sections of pectoral fin rays, whole otoliths with no preparation, and whole otoliths that had been cleared for 1 month in a 70:30 ethanol : glycerin solution. Bias was lower and precision was greater for fin rays than for otoliths; these results were consistent for comparisons within readers (first and second readings by one individual; three readers were used) and between readers (one reading for each reader within a pair). Both otolith methods appeared to misclassify age-1 rainbow smelt. Fin ray ages had the highest precision and provided the best approximation of age estimates inferred from the Lake Ontario population's length frequency distribution and from our understanding of this population. ?? American Fisheries Society 2008.

TNF signaling and macrophages govern fin regeneration in zebrafish larvae.

PubMed

Nguyen-Chi, Mai; Laplace-Builhé, Béryl; Travnickova, Jana; Luz-Crawford, Patricia; Tejedor, Gautier; Lutfalla, Georges; Kissa, Karima; Jorgensen, Christian; Djouad, Farida

2017-08-10

Macrophages are essential for appendage regeneration after amputation in regenerative species. The molecular mechanisms through which macrophages orchestrate blastema formation and regeneration are still unclear. Here, we use the genetically tractable and transparent zebrafish larvae to study the functions of polarized macrophage subsets during caudal fin regeneration. After caudal fin amputation, we show an early and transient accumulation of pro-inflammatory macrophages concomitant with the accumulation of non-inflammatory macrophages which, in contrast to pro-inflammatory macrophages, remain associated to the fin until the end of the regeneration. Chemical and genetic depletion of macrophages suggested that early recruited macrophages that express TNFα are critical for blastema formation. Combining parabiosis and morpholino knockdown strategies, we show that TNFα/TNFR1 signaling pathway is required for the fin regeneration. Our study reveals that TNFR1 has a necessary and direct role in blastema cell activation suggesting that macrophage subset balance provides the accurate TNFα signal to prime regeneration in zebrafish.

Determination of optimum fin profile for a zero-G capillary drained condenser

NASA Technical Reports Server (NTRS)

Mccormick, John A.; Valenzuela, Javier A.; Choudhury, Dipanker

1990-01-01

This paper presents the analytical formulation and numerical results for heat transfer in a high heat flux condenser that relies on capillary flow along shaped fins (Gregorig surfaces) and a drainage network embedded in the condenser walls. Results are shown for a variety of fin profile shapes in order to show the geometric trade-offs involved in seeking a maximum effective heat transfer coefficient for the fin. Predictions of the model show excellent agreement with previously reported measurements for steam. Based on this work, a profile has been selected for a 2 kW ammonia condenser currently under development for use in space. In that design the fin half width is 0.5 mm and the model predicts a heat transfer coefficient referred to the base of the fin of 9 W/sq cm deg C for a heat flux of 10/W sq cm at the base.

Pegasus XL CYGNSS Fin Installation

NASA Image and Video Library

2016-09-21

Technicians prepare to install one of the fins on the Orbital ATK Pegasus XL rocket inside Building 1555 at Vandenberg Air Force Base in California. The fins will provide aerodynamic stability during flight. The rocket is being prepared at Vandenberg, and then will be transported to NASA’s Kennedy Space Center in Florida, attached to the Orbital ATK L-1011 carrier aircraft with NASA’s Cyclone Global Navigation Satellite System (CYGNSS) in its payload fairing. CYGNSS will launch on the Pegasus XL rocket from the Skid Strip at Cape Canaveral Air Force Station. CYGNSS will make frequent and accurate measurements of ocean surface winds throughout the life cycle of tropical storms and hurricanes. The data that CYGNSS provides will enable scientists to probe key air-sea interaction processes that take place near the core of storms, which are rapidly changing and play a critical role in the beginning and intensification of hurricanes.

Pegasus XL CYGNSS Fin Installation

NASA Image and Video Library

2016-09-21

Technicians prepare one of the fins for installation on the Orbital ATK Pegasus XL rocket inside Building 1555 at Vandenberg Air Force Base in California. The fins will provide aerodynamic stability during flight. The rocket is being prepared at Vandenberg, and then will be transported to NASA’s Kennedy Space Center in Florida, attached to the Orbital ATK L-1011 carrier aircraft with NASA’s Cyclone Global Navigation Satellite System (CYGNSS) in its payload fairing. CYGNSS will launch on the Pegasus XL rocket from the Skid Strip at Cape Canaveral Air Force Station. CYGNSS will make frequent and accurate measurements of ocean surface winds throughout the life cycle of tropical storms and hurricanes. The data that CYGNSS provides will enable scientists to probe key air-sea interaction processes that take place near the core of storms, which are rapidly changing and play a critical role in the beginning and intensification of hurricanes.

Pegasus XL CYGNSS Fin Installation

NASA Image and Video Library

2016-09-21

Technicians prepare to install one of the fins on the Orbital ATK Pegasus XL rocket inside Building 1555 at Vandenberg Air Force Base in California. The fins will provide aerodynamic stability during flight. The rocket is being prepared at Vandenberg, and then will be transported to NASA’s Kennedy Space Center in Florida attached to the Orbital ATK L-1011 carrier aircraft with NASA’s Cyclone Global Navigation Satellite System (CYGNSS) in its payload fairing. CYGNSS will launch on the Pegasus XL rocket from the Skid Strip at Cape Canaveral Air Force Station. CYGNSS will make frequent and accurate measurements of ocean surface winds throughout the life cycle of tropical storms and hurricanes. The data that CYGNSS provides will enable scientists to probe key air-sea interaction processes that take place near the core of storms, which are rapidly changing and play a critical role in the beginning and intensification of hurricanes.

Resisting the therapeutic reduction: on the significance of sin.

PubMed

Delkeskamp-Hayes, Corinna

2007-01-01

Sin-talk, though politically incorrect, is indispensable. Placing human life under the "hermeneutic of sin" means acknowledging that one ought to aim flawlessly at God, and that one can fail in this endeavor. None of this can be appreciated within the contemporary post-Christian, mindset, which has attempted to reduce religion to morality and culture. In such a secular context, the guilt-feelings connected with the recognition of sin are considered to be harmful; the eternal benefit of a repentance is disregarded. Nevertheless, spirituality appears to have therapeutic benefits. Therefore attempts are made to re-locate within healthcare a religion shorn of its transcendent claims, so as then to harvest the benefits of a spirituality "saved from sin". This reduction of religiosity to its therapeutic function is nourished by a post-modern constructivist construal of religion. This article critically examines the dis-ingenuity marring such recasting, as well as the incoherence of related attempts to reduce transcendence to solidarity, and to re-shape the significance of religious rituals.

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

USGS Publications Warehouse

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.

Strategies to alleviate original antigenic sin responses to influenza viruses.

PubMed

Kim, Jin Hyang; Davis, William G; Sambhara, Suryaprakash; Jacob, Joshy

2012-08-21

Original antigenic sin is a phenomenon wherein sequential exposure to closely related influenza virus variants reduces antibody (Ab) response to novel antigenic determinants in the second strain and, consequently, impairs the development of immune memory. This could pose a risk to the development of immune memory in persons previously infected with or vaccinated against influenza. Here, we explored strategies to overcome original antigenic sin responses in mice sequentially exposed to two closely related hemagglutinin 1 neuraminidase 1 (H1N1) influenza strains A/PR/8/34 and A/FM/1/47. We found that dendritic cell-activating adjuvants [Bordetella pertussis toxin (PT) or CpG ODN or a squalene-based oil-in-water nanoemulsion (NE)], upon administration during the second viral exposure, completely protected mice from a lethal challenge and enhanced neutralizing-Ab titers against the second virus. Interestingly, PT and NE adjuvants when administered during the first immunization even prevented original antigenic sin in subsequent immunization without any adjuvants. As an alternative to using adjuvants, we also found that repeated immunization with the second viral strain relieved the effects of original antigenic sin. Taken together, our studies provide at least three ways of overcoming original antigenic sin.

The human dark side: evolutionary psychology and original sin.

PubMed

Lee, Joseph; Theol, M

2014-04-01

Human nature has a dark side, something important to religions. Evolutionary psychology has been used to illuminate the human shadow side, although as a discipline it has attracted criticism. This article seeks to examine the evolutionary psychology's understanding of human nature and to propose an unexpected dialog with an enduring account of human evil known as original sin. Two cases are briefly considered: murder and rape. To further the exchange, numerous theoretical and methodological criticisms and replies of evolutionary psychology are explored jointly with original sin. Evolutionary psychology can partner with original sin since they share some theoretical likenesses and together they offer insights into the nature of what it means to be human.

SIN3A mutations are rare in men with azoospermia.

PubMed

Miyamoto, T; Koh, E; Tsujimura, A; Miyagawa, Y; Minase, G; Ueda, Y; Namiki, M; Sengoku, K

2015-11-01

A loss of function of the murine Sin3A gene resulted in male infertility with Sertoli cell-only syndrome (SCOS) phenotype in mice. Here, we investigated the relevance of this gene to human male infertility with azoospermia caused by SCOS. Mutation analysis of SIN3A in the coding region was performed on 80 Japanese patients. However, no variants could be detected. This study suggests a lack of association of SIN3A gene sequence variants with azoospermia caused by SCOS in humans. © 2014 Blackwell Verlag GmbH.

Effects of fin clipping on survival and position-holding behavior of brown darters, Etheostoma edwini

USGS Publications Warehouse

Champagne, C.E.; Austin, J.D.; Jelks, H.L.; Jordan, F.

2008-01-01

Advent of the polymerase chain reaction (PCR) has allowed conservation biologists to use small portions of tissue to obtain genetic material for population genetic and taxonomic study. Fin clips are used extensively in large-sized fishes, but it is unclear how clipping enough fin tissue for genetic analysis will affect survival of smaller fishes such as minnows and darters, which are among the most threatened organisms in North America. We tested for effects of fin clipping on survival and swimming performance of non-threatened Brown Darters (Etheostoma edwini) in order to justify similar tissue collection in co-occurring endangered Okaloosa Darters (E. okaloosae). We collected 48 E. edwini from a small stream in northwest Florida, transported them to the laboratory, and randomly assigned them to one of three experimental groups: control, entire right pectoral fin removed, or rear half of caudal fin removed. Successful amplification of DNA indicated that our fin clips were large enough for genetic analysis using PCR. No mortality occurred during a two-month observation period. Fin regeneration was almost complete and we could not visually distinguish clipped fins from control fins after two months. We then randomly assigned fish into the same three experimental groups, clipped fins, and evaluated their ability to hold position at 20 cm/sec in an experimental flow chamber. Neither fish size nor treatment type affected position-holding behavior. Fin clipping does not adversely affect survival and swimming performance of E. edwini maintained in the laboratory. Additional research on the effects of fin clipping on small-sized fishes should be conducted in the field to evaluate survival under natural conditions. ?? 2008 by the American Society of Ichthyologists and Herpetologists.

The original risk: overtheologizing ethics and undertheologizing sin.

PubMed

Müller, Denis

2007-01-01

The project of articulating a theological ethics on the basis of liturgical anthropology is bound to fail if the necessary consequence is that one has to quit the forum of critical modern rationality. The risk of Engelhardt's approach is to limit rationality to a narrow vision of reason. Sin is not to be understood as the negation of human holiness, but as the negation of divine holiness. The only way to renew theological ethics is to understand sin as the anthropological and ethical expression of the biblical message of the justification by faith only. Sin is therefore a secondary category, which can only by interpreted in light of the positive manifestation of liberation, justification, and grace. The central issue of Christian ethics is not ritual purity or morality, but experience, confession and recognition of our own injustice in our dealing with God and men.

Integral finned heater and cooler for stirling engines

DOEpatents

Corey, John A.

1984-01-01

A piston and cylinder for a Stirling engine and the like having top and bottom meshing or nesting finned conical surfaces to provide large surface areas in close proximity to the working gas for good thermal (addition and subtraction of heat) exchange to the working gas and elimination of the usual heater and cooler dead volume. The piston fins at the hot end of the cylinder are perforated to permit the gas to pass into the piston interior and through a regenerator contained therein.

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

PubMed

Behbahani, Sanaz Bazaz; Tan, Xiaobo

2016-05-04

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.

The heartstrings mutation in zebrafish causes heart/fin Tbx5 deficiency syndrome.

PubMed

Garrity, Deborah M; Childs, Sarah; Fishman, Mark C

2002-10-01

Holt-Oram syndrome is one of the autosomal dominant human "heart-hand" disorders, with a combination of upper limb malformations and cardiac defects. Holt-Oram syndrome is caused by mutations in the TBX5 gene, a member of a large family of T-box transcription factors that play important roles in cell-type specification and morphogenesis. In a screen for mutations affecting zebrafish cardiac function, we isolated the recessive lethal mutant heartstrings, which lacks pectoral fins and exhibits severe cardiac dysfunction, beginning with a slow heart rate and progressing to a stretched, non-functional heart. We mapped and cloned the heartstrings mutation and find it to encode the zebrafish ortholog of the TBX5 gene. The heartstrings mutation causes premature termination at amino acid 316. Homozygous mutant embryos never develop pectoral fin buds and do not express several markers of early fin differentiation. The total absence of any fin bud differentiation distinguishes heartstrings from most other mutations that affect zebrafish fin development, suggesting that Tbx5 functions very early in the pectoral fin induction pathway. Moderate reduction of Tbx5 by morpholino causes fin malformations, revealing an additional early requirement for Tbx5 in coordinating the axes of fin outgrowth. The heart of heartstrings mutant embryos appears to form and function normally through the early heart tube stage, manifesting only a slight bradycardia compared with wild-type siblings. However, the heart fails to loop and then progressively deteriorates, a process affecting the ventricle as well as the atrium. Relative to mammals, fish require lower levels of Tbx5 to produce malformed appendages and display whole-heart rather than atrial-predominant cardiac defects. However, the syndromic deficiencies of tbx5 mutation are remarkably well retained between fish and mammals.

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

PubMed

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.

Development and Application of Collaborative Optimization Software for Plate - fin Heat Exchanger

NASA Astrophysics Data System (ADS)

Chunzhen, Qiao; Ze, Zhang; Jiangfeng, Guo; Jian, Zhang

2017-12-01

This paper introduces the design ideas of the calculation software and application examples for plate - fin heat exchangers. Because of the large calculation quantity in the process of designing and optimizing heat exchangers, we used Visual Basic 6.0 as a software development carrier to design a basic calculation software to reduce the calculation quantity. Its design condition is plate - fin heat exchanger which was designed according to the boiler tail flue gas. The basis of the software is the traditional design method of the plate-fin heat exchanger. Using the software for design and calculation of plate-fin heat exchangers, discovery will effectively reduce the amount of computation, and similar to traditional methods, have a high value.

Impact of line edge roughness on the performance of 14-nm FinFET: Device-circuit Co-design

NASA Astrophysics Data System (ADS)

Rathore, Rituraj Singh; Rana, Ashwani K.

2018-01-01

With the evolution of sub-20 nm FinFET technology, line edge roughness (LER) has been identified as a critical problem and may result in critical device parameter variation and performance limitation in the future VLSI circuit application. In the present work, an analytical model of fin-LER has been presented, which shows the impact of correlated and uncorrelated LER on FinFET structure. Further, the influence of correlated and uncorrelated fin- LER on all electrical performance parameters is thoroughly investigated using the three-dimensional (3-D) Technology Computer Aided Design (TCAD) simulations for 14-nm technology node. Moreover, the impact of all possible fin shapes on threshold voltage (VTH), drain induced barrier lowering (DIBL), on-current (ION), and off-current (IOFF) has been compared with the well calibrated rectangular FinFET structure. In addition, the influence of all possible fin geometries on the read stability of six-transistor (6-T) Static-Random-Access-Memory (SRAM) has been investigated. The study reveals that fin-LER plays a vital role as it directly governs the electrostatics of the FinFET structure. This has been found that there is a high degree of fluctuations in all performance parameters for uncorrelated fin-LER type FinFETs as compared to correlated fin-LER with respect to rectangular FinFET structure. This paper gives physical insight of FinFET design, especially in sub-20 nm technology nodes by concluding that the impact of LER on electrical parameters are minimum for correlated LER.

Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus

PubMed Central

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. PMID:26812485

Role of fin material and nanofluid in performance enhancement of automobile radiator

NASA Astrophysics Data System (ADS)

Jadar, Raju; Shashishekar, K. S.; Channa Keshava Naik, N.

2018-04-01

An effective cooling system can avoid engine and its components from overheating and helps in achieving optimum engine performance. This work deals with the fabrication and performance evaluation of an automobile radiator with i) Aluminum fins and ii) Al-MWCNT fins using 0.1 w/v% f-MWCNT nanofluid. F-MWCNT nanoparticles in the base fluid improves the rate of heat transfer in an automobile radiator integrated with Al-MWCNT fins. The enhancement of heat transfer mainly depends on the quantity of F-MWCNT nanoparticles added to the host fluid. During the study it was found that at a low weight by volume concentration of nanofluid the heat transfer enhancement of 8% was achieved using Al-MWCNT fins compared to base fluid.

Velocity Deficits in the Wake of Model Lemon Shark Dorsal Fins Measured with Particle Image Velocimetry

NASA Astrophysics Data System (ADS)

Terry, K. N.; Turner, V.; Hackett, E.

2017-12-01

Aquatic animals' morphology provides inspiration for human technological developments, as their bodies have evolved and become adapted for efficient swimming. Lemon sharks exhibit a uniquely large second dorsal fin that is nearly the same size as the first fin, the hydrodynamic role of which is unknown. This experimental study looks at the drag forces on a scale model of the Lemon shark's unique two-fin configuration in comparison to drag forces on a more typical one-fin configuration. The experiments were performed in a recirculating water flume, where the wakes behind the scale models are measured using particle image velocimetry. The experiments are performed at three different flow speeds for both fin configurations. The measured instantaneous 2D distributions of the streamwise and wall-normal velocity components are ensemble averaged to generate streamwise velocity vertical profiles. In addition, velocity deficit profiles are computed from the difference between these mean streamwise velocity profiles and the free stream velocity, which is computed based on measured flow rates during the experiments. Results show that the mean velocities behind the fin and near the fin tip are smallest and increase as the streamwise distance from the fin tip increases. The magnitude of velocity deficits increases with increasing flow speed for both fin configurations, but at all flow speeds, the two-fin configurations generate larger velocity deficits than the one-fin configurations. Because the velocity deficit is directly proportional to the drag force, these results suggest that the two-fin configuration produces more drag.

First description of a musculoskeletal linkage in an adipose fin: innovations for active control in a primitively passive appendage

PubMed Central

Stewart, Thomas A.; Hale, Melina E.

2013-01-01

Adipose fins are enigmatic appendages found between the dorsal and caudal fins of some teleostean fishes. Long thought to be vestigial, degenerate second dorsal fins, remnants of the primitive gnathostome condition, adipose fins have since been recognized as novel morphologies. Unique among the fins of extant fishes, adipose fins have uniformly been described as passive structures, with no associated musculature. Here we provide the first description of a musculoskeletal linkage in an adipose fin, identified in the sun catfish Horabagrus brachysoma. Modified supracarinalis posterior muscles insert from the dorsal midline anterior to the adipose fin by tendons onto the fin base. An additional pair of posterior adipose-fin muscles also inserts upon the fin base and lay posterolateral to the fin, superficial to the axial muscle. This musculoskeletal linkage is an evolutionary innovation, a novel mechanism for controlling adipose-fin movement. These muscles appear to exemplify two approaches by which fins evolve to be actively controlled. We hypothesize that the anterior muscles arose through co-option of an existing fin linkage, while the posterior muscles originated as de novo fin muscles. These findings present adipose fins as a rich system within which to explore the evolution of novel vertebrate appendages. PMID:23135670

A comparison of pectoral fin contact between two different wild dolphin populations

USGS Publications Warehouse

Dudzinski, K.M.; Gregg, J.D.; Ribic, C.A.; Kuczaj, S.A.

2009-01-01

Contact behaviour involving the pectoral fin has been documented in a number of dolphin species, and various explanations about its function have been offered. Pectoral fin contact can take a variety of forms, and involves a number of body parts and movements, likely differing depending upon social or ecological context. For this study, we compare the pectoral fin contact behaviour of two species of wild dolphins: Indo-Pacific bottlenose dolphins (Tursiops aduncus) from around Mikura Island, Japan, and Atlantic spotted dolphins (Stenella frontalis) from The Bahamas. The two study populations exhibit surprising similarity in the ways in which pectoral fin contacts are used, despite differences in species and environmental conditions at the two sites. Differences in contact rates for calves between the two sites suggest that calf-focused aggression from adult dolphins is more prevalent at Mikura than in The Bahamas. Our results suggest that pectoral fin contact behaviour seems to be driven primarily by social pressures, and may be similar in function to allogrooming described in primates. ?? 2008 Elsevier B.V.

Protective Role of Comfrey Leave Extracts on UV-induced Zebrafish Fin Damage

PubMed Central

Cheng, Chien-Chung; Chou, Chi-Yuan; Chang, Yao-Chin; Wang, Hsuan-Wen; Wen, Chi-Chung; Chen, Yau-Hung

2014-01-01

In zebrafish, UV exposure leads to fin malformation phenotypes including fin reduction or absence. The present study evaluated UV-protective activities of comfrey leaves extracts in a zebrafish model by recording fin morphological changes. Chemopreventive effects of comfrey leave extracts were evaluated using Kaplan-Meier analysis and Cox proportional hazards regression. The results showed that (1) the mean times of return to normal fin in the UV+comfrey (50 and 100 ppm) groups were 3.43 and 2.86 days and were quicker compared with that in the UV only group (4.21 days); (2) zebrafish fins in the UV+comfrey (50 and 100 ppm) groups were 2.05 and 3.25 times more likely to return to normal than those in the UV only group; and (3) comfrey leave extracts had UV-absorbance abilities and significantly reduced ROS production in UV-exposed zebrafish embryos, which may attenuate UV-mediated apoptosis. In conclusion, comfrey leaves extracts may have the potential to be developed as UV-protective agents to protect zebrafish embryos from UV-induced damage. PMID:25352712

Utilizing chemo-mechanically functionalized oscillating fins to ``catch and release'' nanoparticles in binary flow

NASA Astrophysics Data System (ADS)

Liu, Ya; Ma, Yongting; Bhattacharya, Amitabh; Kuksenok, Olga; He, Ximin; Aizenberg, Joanna; Balazs, Anna

2013-11-01

In biomimetics, designing an effective ``catch and release'' device for the selective removal of target species from the surrounding solution is critical for developing autonomous sensors and sorters. Using computational simulation, we model an array of oscillating fins that are tethered on the floor of a microchannel and immersed in a binary-fluid stream. During the oscillation, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely within the lower stream when they are tilted. We introduce specific adhesive interactions between the fins and particulates in the solution and determine conditions where the oscillating fins can selectively bind (``catch'') target nanoparticles within the upper fluid stream and then release these particles into the lower stream. We isolate the effects of chemical wetting on the fins (e.g., wetting contact angle between fins and fluid) and mechanical parameters (e.g., frequency of fins' oscillations) that lead to the efficient extraction of target species from the upper stream and placement into the lower fluid. Our understanding provides fundamental insights into the system's complex dynamics and mechanism for detection, separation, and purification of multi-component mixtures.

Seasonal and geographical patterns of fin whale song in the western North Atlantic Ocean.

PubMed

Morano, Janelle L; Salisbury, Daniel P; Rice, Aaron N; Conklin, Karah L; Falk, Keri L; Clark, Christopher W

2012-08-01

Male fin whales, Balaenoptera physalus, produce a song consisting of 20 Hz notes at regularly spaced time intervals. Previous studies identified regional differences in fin whale internote intervals (INI), but seasonal changes within populations have not been closely examined. To understand the patterns of fin whale song in the western North Atlantic, the seasonal abundance and acoustic features of fin whale song are measured from two years of archival passive acoustic recordings at two representative locations: Massachusetts Bay and New York Bight. Fin whale 20 Hz notes are detected on 99% of recorded days. In both regions, INI varies significantly throughout the year as two distinct periods: a "short-INI" season in September-January (9.6 s) and a "long-INI" season in March-May (15.1 s). February and June-August are transitional-INI months, with higher variability. Note abundance decreases with increasing INI, where note abundance is significantly lower in April-August than in September-January. Short-INI and high note abundance correspond to the fin whale reproductive season. The temporal variability of INI may be a mechanism by which fin whale individuals encode and communicate a variety of behaviorally relevant information.

Experimental investigation of vortices shed by various wing fin configurations. M.S. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Iversen, J.; Moghadam, M.

1981-01-01

Forty-six different fins, which were members of twelve plan-form families, were tested. A two dimensional Boeing single element airfoil at an angle of attack of eight degrees and a sweepback angle of thirty-two was used to simulate a portion of the wing of a generator aircraft. Various free stream velocities were used to test any individual fin at its particular angle of attack. While the fin itself was mounted on the upper surface of the generator model, the angle of attack of each fin was varied until stall was reached and/or passed. The relative fin vortex strengths were measured in two ways. First, the maximum angular velocity of a four blade rotor placed in the fin vortex center was measured with the use of a stroboscope. Second, the maximum rolling moment on a following wing model placed in the fin vortex center was measured by a force balance.

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

PubMed

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

2015-11-25

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.

A flow separation study over a shortfin mako shark pectoral fin

NASA Astrophysics Data System (ADS)

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.

Dma1-dependent degradation of SIN proteins during meiosis in Schizosaccharomyces pombe.

PubMed

Krapp, Andrea; Simanis, Viesturs

2014-07-15

The Schizosaccharomyces pombe septation initiation network (SIN) is required for cytokinesis during vegetative growth and for spore formation during meiosis. Regulation of the SIN during mitosis has been studied extensively, but less is known about its meiotic regulation. Here, we show that several aspects of SIN regulation differ between mitosis and meiosis. First, the presence of GTP-bound Spg1p is not the main determinant of the timing of Cdc7p and Sid1p association with the spindle pole body (SPB) during meiosis. Second, the localisation dependencies of SIN proteins differ from those in mitotic cells, suggesting a modified functional organisation of the SIN during meiosis. Third, there is stage-specific degradation of SIN components in meiosis; Byr4p is degraded after meiosis I, whereas the degradation of Cdc7p, Cdc11p and Sid4p occurs after the second meiotic division and depends upon the ubiquitin ligase Dma1p. Finally, Dma1p-dependent degradation is not restricted to the SIN, as we show that Dma1p is needed for the degradation of Mcp6p (also known as Hrs1p) during meiosis I. Taken together, these data suggest that stage-specific targeted proteolysis plays an important role in regulating meiotic progression. © 2014. Published by The Company of Biologists Ltd.

Prediction of the electron redundant SinNn fullerenes

NASA Astrophysics Data System (ADS)

Yang, Huihui; Song, Yan; Zhang, Yan; Chen, Hongshan

2018-05-01

The stabilities and electronic structures of SimAln-mNn and SinNn (n = 16, 20, m = 12 and n = 24, m = 16) fullerene-like cages have been investigated using density functional method B3LYP and the second-order perturbation theory MP2. The results show that the SimAln-mNn and SinNn fullerenes are more stable than the AlN counterparts. Comparing with the corresponding AlnNn cages, one silicon atom in each Si2N2 square protrudes and the excess electrons reside as lone pair electrons at the outside of the protrudent Si atoms. Analyses on the electronic structures suggest that the Sisbnd N bonds are covalent bonding with strong polarity. The ELF (electron localization function) shows large electron pair probability between Si and N atoms. The orbital interactions between Si and N are stronger than that between Al and N atoms; the overlap integral is 0.40 per Sisbnd N bond in SinNn and 0.34 per Alsbnd N bond in AlnNn. The AIM (atoms in molecule) charges on the Al atoms in AlnNn and SimAln-mNn are 2.37 and 2.40. The charges on the in-plane and protrudent Si atoms are about 2.88 and 1.50 respectively. Considering the large local dipole moments around the protrudent Si atoms, the electrostatic interactions are also favorable to the SiN cages.

Analytical study on the thermal performance of a partially wet constructal T-shaped fin

NASA Astrophysics Data System (ADS)

Hazarika, Saheera Azmi; Zeeshan, Mohd; Bhanja, Dipankar; Nath, Sujit

2017-07-01

The present paper addresses the thermal analysis of a T-shaped fin under partially wet condition by adopting a cubic variation of the humidity ratio of saturated air with the corresponding fin surface temperature. The point separating the dry and wet parts may lie either in the flange or stem part of the fin and so, two different cases having different governing equations and boundary conditions are analyzed in this paper. Since the governing equations are highly non-linear, they are solved by using an analytical technique called the Differential Transform Method and subsequently, the dry fin length, temperature distribution and fin performances are evaluated and analyzed for a wide range of the various psychometric, geometric and thermo-physical parameters. Finally, it can be highlighted that relative humidity has a pronounced effect on the performance parameters when the fin surface is partially wet whereas this effect is marginally small for fully wet surface.

Filmwise Condensation of Steam on Externally-Finned Horizontal Tubes.

DTIC Science & Technology

1983-12-01

via gravity to the boiler. The auxiliary condenser was constructed of two 9.5-mm (3/8-in) water- cooled ccpper lines helically coiled to a height of...34. " . .. . ’ . .- .. ’. .. .- . . . i . ’ -, - NPS69-83-003 - m NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS FILMWISE CONDENSATION OF STEAM ON EXTERNALLY-FINNED...and SubEtee) 5. TYPE OF REPORT & PERIOD COVERED Filmwise Condensation of Steam on Master Thesis; Externally-Finned Horizontal Tubes D e r1 6

Flame-spreading phenomena in the fin-slot region of a solid rocket motor

NASA Astrophysics Data System (ADS)

Kuo, K. K.; Kokal, R. A.; Paulauskas, M.; Alaksin, P.; Lee, L. S.

1993-06-01

Flame-spreading processes in the fin-slot regions of solid-propellant motor grains have the potential to influence the behavior of the overall ignition transient. The work being done on this project is aimed at obtaining a better understanding of the flame-spreading processes in rocket motors with aft-end fin slots. Non-intrusive optical diagnostic methods were employed to acquire flame-spreading measurements in the fin-slot region of a subscale rocket motor. Highly non-uniform flame-spreading processes were observed in both the deep and shallow fin regions of the test rig. The average flame-spreading rates in the fin-slot region were found to be two orders of magnitude less than those in the circular port region of a typical rocket motor. The flame-spreading interval was found to correlate well with the local pressurization rates. A higher pressurization rate produces a shorter flame-spreading time interval.

Swimming performance of a bio-inspired robotic vessel with undulating fin propulsion.

PubMed

Liu, Hanlin; Curet, Oscar M

2018-06-18

Undulatory fin propulsion exhibits high degree of maneuver control -- an ideal for underwater vessels exploring complex environments. In this work, we developed and tested a self-contained, free-swimming robot with a single undulating fin running along the length of the robot, which controls both forward motion and directional maneuvers. We successfully replicated several maneuvers including forward swimming, reversed motion, diving, station-keeping and vertical swimming. For each maneuver, a series of experiments were performed as a function of fin frequency, wavelength and traveling wave direction to measure swimming velocities, orientation angles and mean power consumption. In addition, three-dimensional flow fields were measured during forward swimming and station-keeping using volumetric particle image velocimetry (PIV). The efficiency for forward swimming was compared using three metrics: cost of transport, wave efficiency and Strouhal number. The results indicate that the cost of transport exhibits a V-shape trend with the minimum value at low swimming velocity. The robot can reach optimal wave efficiency and locomotor performance at a range of 0.2 to 0.4 St. Volumetric PIV data reveal the shed of vortex tubes generated by the fin during forward swimming and station keeping. For forward swimming, a series of vortex tubes are shed off the fin edge with a lateral and downward direction with respect to the longitudinal axis of the fin. For station keeping, flow measurements suggest that the vortex tubes are shed at the mid-section of the fin while the posterior and anterior segment of the vortex stay attached to the fin. These results agree with the previous vortex structures based on simulations and 2D PIV. The further development of this vessel with high maneuverability and station keeping performance can be used for oceanography, coastal exploration, defense, oil industry and other marine industries where operations are unsafe or impractical for divers or

Parallel Fin ORU Thermal Interface for space applications. [Orbital Replaceable Unit

NASA Technical Reports Server (NTRS)

Stobb, C. A.; Limardo, Jose G.

1992-01-01

The Parallel Fin Thermal Interface has been developed as an Orbital Replaceable Unit (ORU) interface. The interface transfers heat from an ORU baseplate to a Heat Acquisition Plate (HAP) through pairs of fins sandwiched between insert plates that press against the fins with uniform pressure. The insert plates are spread apart for ORU baseplate separation and replacement. Two prototype interfaces with different fin dimensions were built (Model 140 and 380). Interfacing surface samples were found to have roughnesses of 56 to 89 nm. Conductance values of 267 to 420 W/sq m C were obtained for the 140 model in vacuum with interface pressures of 131 to 262 kPa (19 to 38 psi). Vacuum conductances ranging from 176 to 267 W/sq m F were obtained for the 380 model at interface pressures of 97 to 152 kPa (14 and 22 psi). Correlations from several sources were found to agree with test data within 20 percent using thermal math models of the interfaces.

Testing Momentum Enhancement of Ribbon Fin Based Propulsion Using a Robotic Model With an Adjustable Body

NASA Astrophysics Data System (ADS)

English, Ian; Curet, Oscar

2016-11-01

Lighthill and Blake's 1990 momentum enhancement theory suggests there is a multiplicative propulsive effect linked to the ratio of body and fin heights in Gymnotiform and Balistiform swimmers, which propel themselves using multi-rayed undulating fins while keeping their bodies mostly rigid. Proof of such a momentum enhancement could have a profound effect on unmanned underwater vehicle design and shed light on the evolutionary advantage to body-fin ratios found in nature, shown as optimal for momentum enhancement in Lighthill and Blake's theory. A robotic ribbon fin with twelve independent fin rays, elastic fin membrane, and a body of adjustable height was developed specifically to experimentally test momentum enhancement. Thrust tests for various body heights were conducted in a recirculating flow tank at different flow speeds and fin flapping frequencies. When comparing thrust at different body heights, flow speeds, and frequencies to a 'no-body' thrust test case at each frequency and flow speed, data indicate there is no momentum enhancement factor due to the presence of a body on top of an undulating fin. This suggests that if there is a benefit to a specific ratio between body and fin height, it is not due to momentum enhancement.

Understanding original antigenic sin in influenza with a dynamical system.

PubMed

Pan, Keyao

2011-01-01

Original antigenic sin is the phenomenon in which prior exposure to an antigen leads to a subsequent suboptimal immune response to a related antigen. Immune memory normally allows for an improved and rapid response to antigens previously seen and is the mechanism by which vaccination works. I here develop a dynamical system model of the mechanism of original antigenic sin in influenza, clarifying and explaining the detailed spin-glass treatment of original antigenic sin. The dynamical system describes the viral load, the quantities of healthy and infected epithelial cells, the concentrations of naïve and memory antibodies, and the affinities of naïve and memory antibodies. I give explicit correspondences between the microscopic variables of the spin-glass model and those of the present dynamical system model. The dynamical system model reproduces the phenomenon of original antigenic sin and describes how a competition between different types of B cells compromises the overall effect of immune response. I illustrate the competition between the naïve and the memory antibodies as a function of the antigenic distance between the initial and subsequent antigens. The suboptimal immune response caused by original antigenic sin is observed when the host is exposed to an antigen which has intermediate antigenic distance to a second antigen previously recognized by the host's immune system.

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

NASA Astrophysics Data System (ADS)

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.

Demonstration of Corrosion-Resistant Coatings for Air-Conditioning Coils and Fins

DTIC Science & Technology

2015-06-01

of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by...13 Figure 9. HVAC condenser fins with Coating E after on-site exposure for 24 months...14 Figure 10. HVAC condenser fins with

Geometric and electronic structures of silicon-sodium binary clusters. I. Ionization energy of SinNam

NASA Astrophysics Data System (ADS)

Kishi, Reiko; Iwata, Suehiro; Nakajima, Atsushi; Kaya, Koji

1997-08-01

Sodium doped silicon clusters (SinNam; 1⩽n⩽14, 1⩽m⩽5) produced by two types of laser vaporization were studied. The adsorption of Na atoms on the Sin clusters leads the substantial lowering of the ionization energy, Ei, of SinNam clusters. Their reactivity toward NO molecules was measured with a fast flow reactor, and the anticorrelation between the Eis and the reactivity was clearly observed; species having low Ei exhibit high reactivity and vice versa. Moreover, the clear parallelism between the Eis of SinNa and the EAs of Sin is found. This is consistent with the fact that the structure of SinNa clusters keeps the frame of the corresponding Sin cluster unchanged and that the electronic structure of SinNa is similar to that of the corresponding negative ion Sin-. In addition to the experimental studies, the geometries, adsorption energies, and vertical ionization energies of SinNa (n=1-7) were investigated with ab initio MO calculations including electron correlation; The Møller-Plesset perturbation theory was used and the configuration interaction (CI) calculation was carried out, particularly for a diatomic molecule, SiNa.

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

PubMed Central

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

Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

NASA Astrophysics Data System (ADS)

Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

Fuzzy adaptive integration scheme for low-cost SINS/GPS navigation system

NASA Astrophysics Data System (ADS)

Nourmohammadi, Hossein; Keighobadi, Jafar

2018-01-01

Due to weak stand-alone accuracy as well as poor run-to-run stability of micro-electro mechanical system (MEMS)-based inertial sensors, special approaches are required to integrate low-cost strap-down inertial navigation system (SINS) with global positioning system (GPS), particularly in long-term applications. This paper aims to enhance long-term performance of conventional SINS/GPS navigation systems using a fuzzy adaptive integration scheme. The main concept behind the proposed adaptive integration is the good performance of attitude-heading reference system (AHRS) in low-accelerated motions and its degradation in maneuvered or accelerated motions. Depending on vehicle maneuvers, gravity-based attitude angles can be intelligently utilized to improve orientation estimation in the SINS. Knowledge-based fuzzy inference system is developed for decision-making between the AHRS and the SINS according to vehicle maneuvering conditions. Inertial measurements are the main input data of the fuzzy system to determine the maneuvering level during the vehicle motions. Accordingly, appropriate weighting coefficients are produced to combine the SINS/GPS and the AHRS, efficiently. The assessment of the proposed integrated navigation system is conducted via real data in airborne tests.

The effect of ether anesthesia on fin-clipping rate

USGS Publications Warehouse

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.

Measurement of frost characteristics on heat exchanger fins. Part 1: Test facility and instrumentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, L.; Chen, H.; Besant, R.W.

1999-07-01

A special test facility was developed to characterize frost growing on heat exchanger fins where the cold surfaces and the air supply conditions were similar to those experienced in freezers, i.e., cold surface temperatures ranging from {minus}35 C to {minus}40 C, air supply temperatures from {minus}10 C to {minus}20 C, and 80% to 100% relative humidity (RH). This test facility included a test section with removable fins to measure the frost height and mass concentration. Frost height on heat exchanger fins was measured using a new automated laser scanning system to measure the height of frost and its distribution onmore » selected fins. The increase in air pressure loss resulting from frost growth on the fins was measured directly in the test loop. The frost mass accumulation distribution was measured for each test using special pre-etched fins that could be easily subdivided and weighed. The total heat rate was measured using a heat flux meter. These frost-measuring instruments were calibrated and the uncertainty of each is stated.« less

Effect of morphological fin curl on the swimming performance and station-holding ability of juvenile shovelnose sturgeon

USGS Publications Warehouse

Deslauriers, David; Johnston, Ryan; Chipps, Steven R.

2016-01-01

We assessed the effect of fin-curl on the swimming and station-holding ability of juvenile shovelnose sturgeon Scaphirhynchus platorynchus (mean fork length = 17 cm; mean weight = 16 g; n = 21) using a critical swimming speed test performed in a small swim chamber (90 L) at 20°C. We quantified fin-curl severity using the pectoral fin index. Results showed a positive relationship between pectoral fin index and critical swimming speed indicative of reduced swimming performance displayed by fish afflicted with a pectoral fin index < 8%. Fin-curl severity, however, did not affect the station-holding ability of individual fish. Rather, fish affected with severe fin-curl were likely unable to use their pectoral fins to position their body adequately in the water column, which led to the early onset of fatigue. Results generated from this study should serve as an important consideration for future stocking practices.

Filmwise Condensation on Low Integral-Fin Tubes of Different Diameter

DTIC Science & Technology

1988-12-01

the prime mover of condensate . Therefore, the Nusselt analysis was not valid for finned tubes. They therefore divided the finned tube into two regions...the objectives of this thesis. Prior to these modifications, cooling water to the secondary condenser was con- tained in two helically wound coils made...temperature difference across condensate film (K), il = dynamic viscosity of condensate (N. s/m 2). By substituting the Nusselt - and the Sieder-Tate

Large Scale Density Estimation of Blue and Fin Whales (LSD)

DTIC Science & Technology

2014-09-30

172. McDonald, MA, Hildebrand, JA, and Mesnick, S (2009). Worldwide decline in tonal frequencies of blue whale songs . Endangered Species Research 9...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...estimating blue and fin whale density that is effective over large spatial scales and is designed to cope with spatial variation in animal density utilizing

Development of a Four-Fin Bio-Inspired UUV: CFD Studies

DTIC Science & Technology

2012-09-04

6.5ʺ″, V= 1kt, δ = -43.6°. .................................. 17   Fig. 32. Particles traces just near stroke reversal of the front and rear fins...have been studied to understand how certain aquatic animals achieve their high levels of controllability. Blake [1] determined that in low- speed...fin, the amplitude of the flapping and starting location of the down stroke . These simulations were performed in order to evaluate the hydrodynamic

Advanced composite vertical fin for L-1011 aircraft

NASA Technical Reports Server (NTRS)

Jackson, A. C.

1984-01-01

The structural box of the L-1011 vertical fin was redesigned using advanced composite materials. The box was fabricated and ground tested to verify the structural integrity. This report summarizes the complete program starting with the design and analysis and proceeds through the process development ancillary test program production readiness verification testing, fabrication of the full-scale fin boxes and the full-scale ground testing. The program showed that advanced composites can economically and effectively be used in the design and fabrication of medium primary structures for commercial aircraft. Static-strength variability was demonstrated to be comparable to metal structures and the long term durability of advanced composite components was demonstrated.

Sin, suffering, and the need for the theological virtues.

PubMed

Jones, David Albert

2006-08-01

This article examines the account of the relationship between sin and suffering provided by J. L. A. Garcia in "Sin and Suffering in a Catholic Understanding of Medical Ethics," in this issue. Garcia draws on the (Roman) Catholic tradition and particularly on the thought of Thomas Aquinas, who remains an important resource for Catholic theology. Nevertheless, his interpretation of Thomas is open to criticism, both in terms of omissions and in terms of positive claims. Garcia includes those elements of Thomas that are purely philosophical, such as natural law and acquired virtue, but neglects the theological and infused virtues, the gifts and fruits of the Holy Spirit, and the beatitudes. These omissions distort his account of the Christian life so that he underplays both the radical problem posed by sin (and suffering), and the radical character of the ultimate solution: redemption in Christ through the grace of the Holy Spirit.

Anatomy and muscle activity of the dorsal fins in bamboo sharks and spiny dogfish during turning maneuvers.

PubMed

Maia, Anabela; Wilga, Cheryl D

2013-11-01

Stability and procured instability characterize two opposing types of swimming, steady and maneuvering, respectively. Fins can be used to manipulate flow to adjust stability during swimming maneuvers either actively using muscle control or passively by structural control. The function of the dorsal fins during turning maneuvering in two shark species with different swimming modes is investigated here using musculoskeletal anatomy and muscle function. White-spotted bamboo sharks are a benthic species that inhabits complex reef habitats and thus have high requirements for maneuverability. Spiny dogfish occupy a variety of coastal and continental shelf habitats and spend relatively more time cruising in open water. These species differ in dorsal fin morphology and fin position along the body. Bamboo sharks have a larger second dorsal fin area and proportionally more muscle insertion into both dorsal fins. The basal and radial pterygiophores are plate-like structures in spiny dogfish and are nearly indistinguishable from one another. In contrast, bamboo sharks lack basal pterygiophores, while the radial pterygiophores form two rows of elongated rectangular elements that articulate with one another. The dorsal fin muscles are composed of a large muscle mass that extends over the ceratotrichia overlying the radials in spiny dogfish. However, in bamboo sharks, the muscle mass is divided into multiple distinct muscles that insert onto the ceratotrichia. During turning maneuvers, the dorsal fin muscles are active in both species with no differences in onset between fin sides. Spiny dogfish have longer burst durations on the outer fin side, which is consistent with opposing resistance to the medium. In bamboo sharks, bilateral activation of the dorsal in muscles could also be stiffening the fin throughout the turn. Thus, dogfish sharks passively stiffen the dorsal fin structurally and functionally, while bamboo sharks have more flexible dorsal fins, which result from a

Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA) in Shark Fins

PubMed Central

Mondo, Kiyo; Hammerschlag, Neil; Basile, Margaret; Pablo, John; Banack, Sandra A.; Mash, Deborah C.

2012-01-01

Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA. PMID:22412816

Addressing FinFET metrology challenges in 1X node using tilt-beam CD-SEM

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxiao; Zhou, Hua; Ge, Zhenhua; Vaid, Alok; Konduparthi, Deepasree; Osorio, Carmen; Ventola, Stefano; Meir, Roi; Shoval, Ori; Kris, Roman; Adan, Ofer; Bar-Zvi, Maayan

2014-04-01

At 1X node, 3D FinFETS raise a number of new metrology challenges. Gate height and fin height are two of the most important parameters for process control. At present there is a metrology gap in inline in-die measurement of these parameters. In order to fill this metrology gap, in-column beam tilt has been developed and implemented on Applied Materials V4i+ top-down CD-SEM for height measurement. A low tilt (5°) beam and a high tilt (14°) beam have been calibrated to obtain two sets of images providing measurement of sidewall edge width to calculate height in the host. Evaluations are done with applications in both gate height and fin height. TEM correlation with R2 being 0.89 and precision of 0.81nm have been achieved on various in-die features in gate height application. Fin height measurement shows less accuracy (R2 being 0.77) and precision (1.49 nm) due to challenges brought by fin geometry, yet still promising as first attempt. Sensitivity to DOE offset, die-to-die and in-die variation is demonstrated in both gate height and fin height. Process defect is successfully captured from inline wafers with gate height measurement implemented in production. This is the first successful demonstration of inline in-die gate height measurement for 14nm FinFET process control.

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

PubMed

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]. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Neural network detected in a presumed vestigial trait: ultrastructure of the salmonid adipose fin

PubMed Central

Buckland-Nicks, J. A.; Gillis, M.; Reimchen, T. E.

2012-01-01

A wide variety of rudimentary and apparently non-functional traits have persisted over extended evolutionary time. Recent evidence has shown that some of these traits may be maintained as a result of developmental constraints or neutral energetic cost, but for others their true function was not recognized. The adipose fin is small, fleshy, non-rayed and located between the dorsal and caudal fins on eight orders of basal teleosts and has traditionally been regarded as vestigial without clear function. We describe here the ultrastructure of the adipose fin and for the first time, to our knowledge, present evidence of extensive nervous tissue, as well as an unusual subdermal complex of interconnected astrocyte-like cells equipped with primary cilia. The fin contains neither adipose tissue nor fin rays. Many fusiform actinotrichia, comprising dense striated macrofibrils, support the free edge and connect with collagen cables that link the two sides. These results are consistent with a recent hypothesis that the adipose fin may act as a precaudal flow sensor, where its removal can be detrimental to swimming efficiency in turbulent water. Our findings provide insight to the broader themes of function versus constraints in evolutionary biology and may have significance for fisheries science, as the adipose fin is routinely removed from millions of salmonids each year. PMID:21733904

Thrust production and wake structure of a batoid-inspired oscillating fin

PubMed Central

CLARK, R. P.; SMITS, A. J.

2009-01-01

Experiments are reported on the hydrodynamic performance of a flexible fin. The fin replicates some features of the pectoral fin of a batoid fish (such as a ray or skate) in that it is actuated in a travelling wave motion, with the amplitude of the motion increasing linearly along the span from root to tip. Thrust is found to increase with non-dimensional frequency, and an optimal oscillatory gait is identified. Power consumption measurements lead to the computation of propulsive efficiency, and an optimal efficiency condition is evaluated. Wake visualizations are presented, and a vortex model of the wake near zero net thrust is suggested. Strouhal number effects on the wake topology are also illustrated. PMID:19746188

Thrust Production and Wake Structure of a Batoid-Inspired Oscillating Fin

NASA Astrophysics Data System (ADS)

Clark, Richard

2005-11-01

Experiments are reported on the hydrodynamic performance of a flexible fin. The fin replicates some features of the pectoral fin of a batoid fish (such as a ray or skate) in that it is actuated in a traveling wave motion, with the amplitude of the motion increasing linearly along the span from root to tip. Thrust is found to increase with non-dimensional frequency, and an optimal oscillatory gait is identified. Power consumption measurements lead to the computation of Froude efficiency, and an optimal efficiency condition is evaluated. Wake visualizations are presented, and a vortex model of the wake near zero net thrust is suggested. Strouhal number effects on the wake topology are also illustrated.

Thrust production and wake structure of a batoid-inspired oscillating fin

NASA Astrophysics Data System (ADS)

Clark, R. P.; Smits, A. J.

2006-09-01

Experiments are reported on the hydrodynamic performance of a flexible fin. The fin replicates some features of the pectoral fin of a batoid fish (such as a ray or skate) in that it is actuated in a travelling wave motion, with the amplitude of the motion increasing linearly along the span from root to tip. Thrust is found to increase with non-dimensional frequency, and an optimal oscillatory gait is identified. Power consumption measurements lead to the computation of propulsive efficiency, and an optimal efficiency condition is evaluated. Wake visualizations are presented, and a vortex model of the wake near zero net thrust is suggested. Strouhal number effects on the wake topology are also illustrated.

Studying Fin Whales with Seafloor Seismic Networks

NASA Astrophysics Data System (ADS)

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

Singing behavior of fin whales in the Davis Strait with implications for mating, migration and foraging.

PubMed

Simon, Malene; Stafford, Kathleen M; Beedholm, Kristian; Lee, Craig M; Madsen, Peter T

2010-11-01

Most baleen whales undertake migrations between low-latitude breeding grounds and high-latitude feeding grounds. Though little is known about the timing of their migration from the Arctic, fin whales are assumed to undertake a similar migratory pattern. To address questions about habitat use and migrations, the acoustic activity of fin whales in Davis Strait, between Greenland and Canada, was monitored continuously for two years using three bottom-moored acoustic recorders. The acoustic power in the fin whale call frequencies peaked in November-December, showing that fin whales are present in Davis Strait much later in the year than previously expected. The closely timed peaks in song activity and conception time imply that not all fin whales migrate south to mate, but rather start mating at high latitudes rather than or before migrating. Singing activity was strongly linked to daylight hours, suggesting that fin whales might feed during the few daylight hours of the late fall and early Arctic winter. A negative correlation between the advancing sea ice front and power in fin whale frequencies indicates that future changes in sea ice conditions from global warming might change the distribution and migratory patterns of fin whales near the poles.

Morphogen-based simulation model of ray growth and joint patterning during fin development and regeneration.

PubMed

Rolland-Lagan, Anne-Gaëlle; Paquette, Mathieu; Tweedle, Valerie; Akimenko, Marie-Andrée

2012-03-01

The fact that some organisms are able to regenerate organs of the correct shape and size following amputation is particularly fascinating, but the mechanism by which this occurs remains poorly understood. The zebrafish (Danio rerio) caudal fin has emerged as a model system for the study of bone development and regeneration. The fin comprises 16 to 18 bony rays, each containing multiple joints along its proximodistal axis that give rise to segments. Experimental observations on fin ray growth, regeneration and joint formation have been described, but no unified theory has yet been put forward to explain how growth and joint patterns are controlled. We present a model for the control of fin ray growth during development and regeneration, integrated with a model for joint pattern formation, which is in agreement with published, as well as new, experimental data. We propose that fin ray growth and joint patterning are coordinated through the interaction of three morphogens. When the model is extended to incorporate multiple rays across the fin, it also accounts for how the caudal fin acquires its shape during development, and regains its correct size and shape following amputation.

The seven sins in academic behavior in the natural sciences.

PubMed

van Gunsteren, Wilfred F

2013-01-02

"Seven deadly sins" in modern academic research and publishing can be condensed into a list ranging from poorly described experimental or computational setups to falsification of data. This Essay describes these sins and their ramifications, and serves as a code of best practice for researchers in their quest for scientific truth. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of transient behavior of finned coil heat exchangers

NASA Technical Reports Server (NTRS)

Rooke, S. P.; Elissa, M. G.

1993-01-01

The status of research on the transient behavior of finned coil cross-flow heat exchangers using single phase fluids is reviewed. Applications with available analytical or numerical solutions are discussed. Investigation of water-to-air type cross-flow finned tube heat exchangers is examined through the use of simplified governing equations and an up-wind finite difference scheme. The degenerate case of zero air-side capacitance rate is compared with available exact solution. Generalization of the numerical model is discussed for application to multi-row multi-circuit heat exchangers.

Machine-Thermal Coupling Stresses Analysis of the Fin-Type Structural Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Zhang, Zheng; Yue, Hao; Chen, Dongbo; Qin, Delei; Chen, Zijian

2017-05-01

The design structure and heat-transfer mechanism of a thermoelectric generator (TEG) determine its body temperature state. Thermal stress and thermal deformation generated by the temperature variation directly affect the stress state of thermoelectric modules (TEMs). Therefore, the rated temperature and pressing force of TEMs are important parameters in TEG design. Here, the relationships between structural of a fin-type TEG (FTEG) and these parameters are studied by modeling and "machine-thermal" coupling simulation. An indirect calculation method is adopted in the coupling simulation. First, numerical heat transfer calculations of a three-dimensional FTEG model are conducted according to an orthogonal simulation table. The influences of structural parameters for heat transfer in the channel and outer fin temperature distribution are analyzed. The optimal structural parameters are obtained and used to simulate temperature field of the outer fins. Second, taking the thermal calculation results as the initial condition, the thermal-solid coupling calculation is adopted. The thermal stresses of outer fin, mechanical force of spring-angle pressing mechanism, and clamping force on a TEM are analyzed. The simulation results show that the heat transfer area of the inner fin and the physical parameters of the metal materials are the keys to determining the FTEG temperature field. The pressing mechanism's mechanical force can be reduced by reducing the outer fin angle. In addition, a corrugated cooling water pipe, which has cooling and spring functionality, is conducive to establishing an adaptable clamping force to avoid the TEMs being crushed by the thermal stresses in the body.

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

PubMed

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

Aluminum-based one- and two-dimensional micro fin array structures: high-throughput fabrication and heat transfer testing

NASA Astrophysics Data System (ADS)

Primeaux, Philip A.; Zhang, Bin; Zhang, Xiaoman; Miller, Jacob; Meng, W. J.; KC, Pratik; Moore, Arden L.

2017-02-01

Microscale fin array structures were replicated onto surfaces of aluminum 1100 and aluminum 6061 alloy (Al1100/Al6061) sheet metals through room-temperature instrumented roll molding. Aluminum-based micro fin arrays were replicated at room temperature, and the fabrication process is one with high throughput and low cost. One-dimensional (1D) micro fin arrays were made through one-pass rolling, while two-dimensional (2D) micro fin arrays were made by sequential 90° cross rolling with the same roller sleeve. For roll molding of 1D micro fins, fin heights greater than 600 µm were achieved and were shown to be proportional to the normal load force per feature width. At a given normal load force, the fin height was further shown to scale inversely with the hardness of the sheet metal. For sequential 90° cross rolling, morphologies of roll molded 2D micro fin arrays were examined, which provided clues to understand how plastic deformation occurred under cross rolling conditions. A series of pool boiling experiments on low profile Al micro fin array structures were performed within Novec 7100, a widely used commercial dielectric coolant. Results for both horizontal and vertical surface orientations show that roll molded Al micro fin arrays can increase heat flux at fixed surface temperature as compared to un-patterned Al sheet. The present results further suggest that many factors beyond just increased surface area can influence heat transfer performance, including surface finish and the important multiphase transport mechanisms in and around the fin geometry. These factors must also be considered when designing and optimizing micro fin array structures for heat transfer applications.

Fin-and-tube heat exchanger material and inlet velocity effect under frosting conditions

NASA Astrophysics Data System (ADS)

Keryakos, Elie; Toubassy, Joseph; Danlos, Amélie; Clodic, Denis; Descombes, Georges

2017-02-01

The frosting fin-and-tube heat exchanger used in this study is implemented in the dehydration process of a biogas upgrading pilot. Water is separated from the biogas by frosting it at very low temperatures on the cold surfaces of the fin-and-tube heat exchanger. Once frosted, a defrosting system is used to remove water from the process. The main interest of this study is the frosting system. The effects of the biogas velocity, fin material, tube material and frost layer thickness on the performance of the fin-and-tube heat exchanger are investigated. Increasing the biogas velocity tends to increase the frosting layer thickness and the external pressure drop. This will lead to decrease the heat exchanger performance and the frosting cycle duration. The thermal conductivity of the fins and tubes has a major effect on the performance of the heat exchanger. Higher thermal conductivity decreases the heat exchanged surface. A numerical model has been developed, then numerical and experimental results extracted from a biogas upgrading pilot are compared.

Sizing-tube-fin space radiators

NASA Technical Reports Server (NTRS)

Peoples, J. A.

1978-01-01

Temperature and size considerations of the tube fin space radiator were characterized by charts and equations. An approach of accurately assessing rejection capability commensurate with a phase A/B level output is reviewed. A computer program, based on Mackey's equations, is also presented which sizes the rejection area for a given thermal load. The program also handles the flow and thermal considerations of the film coefficient.

Investigation of defect-induced abnormal body current in fin field-effect-transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Kuan-Ju; Tsai, Jyun-Yu; Lu, Ying-Hsin

2015-08-24

This letter investigates the mechanism of abnormal body current at the linear region in n-channel high-k/metal gate stack fin field effect transistors. Unlike body current, which is generated by impact ionization at high drain voltages, abnormal body current was found to increase with decreasing drain voltages. Notably, the unusual body leakage only occurs in three-dimensional structure devices. Based on measurements under different operation conditions, the abnormal body current can be attributed to fin surface defect-induced leakage current, and the mechanism is electron tunneling to the fin via the defects, resulting in holes left at the body terminal.

Utilizing Chemo-mechanically Functionalized Oscillating Fins to ``Catch and Release'' Nanoparticles in Binary Flow

NASA Astrophysics Data System (ADS)

Liu, Ya; Kuksenok, Olga; Bhattacharya, Amitabh; Ma, Yongting; He, Ximin; Aizenberg4, Joanna; Balazs, Anna

2014-03-01

In biomimetics, designing an effective ``catch and release'' device for the selective removal of target species from the surrounding solution is critical for developing autonomous sensors and sorters. Using computer simulations, we model an array of oscillating fins that are tethered on the floor of a microchannel and immersed in a mixture of binary fluid stream and binary nanoparticles. During the oscillation, the fins with the specific chemical wetting reach the upper fluid when they are upright and are entirely immersed within the lower stream when they are tilted. We introduce specific interaction between the fins and particulates in the solution and determine conditions where the oscillating fins can selectively ?catch? target nanoparticles within the upper fluid stream and then release these particles into the lower stream. We isolate the effects of wetting contact angle between fins and fluid and the mode of fins' oscillations that lead to the efficient extraction of target species from the upper stream and their placement into the lower fluid. These studies provide fundamental insights into the system's complex dynamics and mechanism for detection, separation, and purification of multi-component mixtures.

Experimental studies of Savonius wind turbines with variations sizes and fin numbers towards performance

NASA Astrophysics Data System (ADS)

Utomo, Ilham Satrio; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

2018-02-01

The use of renewable energy in Indonesia is still low. Especially the use of wind energy. Wind turbine Savonius is one turbine that can work with low wind speed. However, Savonius wind turbines still have low efficiency. Therefore it is necessary to modify. Modifications by using the fin are expected to increase the positive drag force by creating a flow that can enter the overlap ratio of the gap. This research was conducted using experimental approach scheme. Parameters generated from the experiment include: power generator, power coefficient, torque coefficient. The experimental data will be collected by variation of fin area, horizontal finning, at wind speed 3 m/s - 4,85 m/s. Experimental results show that with the addition of fin can improve the performance of wind turbine Savonius 11%, and by using the diameter of 115 mm fin is able to provide maximum performance in wind turbine Savonius.

Performance analysis of device-level SINS/ACFSS deeply integrated navigation method

NASA Astrophysics Data System (ADS)

Zhang, Hao; Qin, Shiqiao; Wang, Xingshu; Jiang, Guangwen; Tan, Wenfeng

2016-10-01

The Strap-Down Inertial Navigation System (SINS) is a widely used navigation system. The combination of SINS and the Celestial Navigation System (CNS) is one of the popular measures to constitute the integrated navigation system. A Star Sensor (SS) is used as a precise attitude determination device in CNS. To solve the problem that the star image obtained by SS under dynamic conditions is motion-blurred, the Attitude Correlated Frames (ACF) is presented and the star sensor which works based on ACF approach is named ACFSS. Depending on the ACF approach, a novel device-level SINS/ACFSS deeply integrated navigation method is proposed in this paper. Feedback to the ACF process from the error of the gyro is one of the typical characters of the SINS/CNS deeply integrated navigation method. Herein, simulation results have verified its validity and efficiency in improving the accuracy of gyro and it can be proved that this method is feasible in theory.

FIN219/JAR1 and cryptochrome1 antagonize each other to modulate photomorphogenesis under blue light in Arabidopsis

PubMed Central

2018-01-01

Plant development is affected by the integration of light and phytohormones, including jasmonates (JAs). To address the molecular mechanisms of possible interactions between blue light and JA signaling in Arabidopsis thaliana, we used molecular and transgenic approaches to understand the regulatory relationships between FAR-RED INSENSITIVE 219 (FIN219)/JASMONATE RESISTANT1 (JAR1) and the blue-light photoreceptor cryptochrome1 (CRY1). FIN219 overexpression in the wild type resulted in a short-hypocotyl phenotype under blue light. However, FIN219 overexpression in cry1, cry2 and cry1cry2 double mutant backgrounds resulted in phenotypes similar to their respective mutant backgrounds, which suggests that FIN219 function may require blue light photoreceptors. Intriguingly, FIN219 overexpression in transgenic plants harboring ectopic expression of the C terminus of CRY1 (GUS-CCT1), which exhibits a hypersensitive short-hypocotyl phenotype in all light conditions including darkness, led to a rescued phenotype under all light conditions except red light. Further expression studies showed mutual suppression between FIN219 and CRY1 under blue light. Strikingly, FIN219 overexpression in GUS-CCT1 transgenic lines (FIN219-OE/GUS-CCT1) abolished GUS-CCT1 fusion protein under blue light, whereas GUS-CCT1 fusion protein was stable in the fin219-2 mutant background (fin219-2/GUS-CCT1). Moreover, FIN219 strongly interacted with COP1 under blue light, and methyl JA (MeJA) treatment enhanced the interaction between FIN219 and GUS-CCT1 under blue light. Furthermore, FIN219 level affected GUS-CCT1 seedling responses such as anthocyanin accumulation and bacterial resistance under various light conditions and MeJA treatment. Thus, FIN219/JAR1 and CRY1 antagonize each other to modulate photomorphogenic development of seedlings and stress responses in Arabidopsis. PMID:29561841

FIN219/JAR1 and cryptochrome1 antagonize each other to modulate photomorphogenesis under blue light in Arabidopsis.

PubMed

Chen, Huai-Ju; Fu, Tsu-Yu; Yang, Shao-Li; Hsieh, Hsu-Liang

2018-03-01

Plant development is affected by the integration of light and phytohormones, including jasmonates (JAs). To address the molecular mechanisms of possible interactions between blue light and JA signaling in Arabidopsis thaliana, we used molecular and transgenic approaches to understand the regulatory relationships between FAR-RED INSENSITIVE 219 (FIN219)/JASMONATE RESISTANT1 (JAR1) and the blue-light photoreceptor cryptochrome1 (CRY1). FIN219 overexpression in the wild type resulted in a short-hypocotyl phenotype under blue light. However, FIN219 overexpression in cry1, cry2 and cry1cry2 double mutant backgrounds resulted in phenotypes similar to their respective mutant backgrounds, which suggests that FIN219 function may require blue light photoreceptors. Intriguingly, FIN219 overexpression in transgenic plants harboring ectopic expression of the C terminus of CRY1 (GUS-CCT1), which exhibits a hypersensitive short-hypocotyl phenotype in all light conditions including darkness, led to a rescued phenotype under all light conditions except red light. Further expression studies showed mutual suppression between FIN219 and CRY1 under blue light. Strikingly, FIN219 overexpression in GUS-CCT1 transgenic lines (FIN219-OE/GUS-CCT1) abolished GUS-CCT1 fusion protein under blue light, whereas GUS-CCT1 fusion protein was stable in the fin219-2 mutant background (fin219-2/GUS-CCT1). Moreover, FIN219 strongly interacted with COP1 under blue light, and methyl JA (MeJA) treatment enhanced the interaction between FIN219 and GUS-CCT1 under blue light. Furthermore, FIN219 level affected GUS-CCT1 seedling responses such as anthocyanin accumulation and bacterial resistance under various light conditions and MeJA treatment. Thus, FIN219/JAR1 and CRY1 antagonize each other to modulate photomorphogenic development of seedlings and stress responses in Arabidopsis.

Performance ‘S’ Type Savonius Wind Turbine with Variation of Fin Addition on Blade

NASA Astrophysics Data System (ADS)

Pamungkas, S. F.; Wijayanto, D. S.; Saputro, H.; Widiastuti, I.

2018-01-01

Wind power has been receiving attention as the new energy resource in addressing the ecological problems of burning fossil fuels. Savonius wind rotor is a vertical axis wind turbines (VAWT) which has relatively simple structure and low operating speed. These characteristics make it suitable for areas with low average wind speed as in Indonesia. To identify the performance of Savonius rotor in generating electrical energy, this research experimentally studied the effect of fin addition for the ‘S’ shape of Savonius VAWT. The fin is added to fill the space in the blade in directing the wind flow. This rotor has two turbine blades, a rotor diameter of 1.1 m and rotor height of 1.4 m, used pulley transmission system with 1:4.2 multiplication ratio, and used a generator type PMG 200 W. The research was conducted during dry season by measuring the wind speed in the afternoon. The average wind speed in the area is 2.3 m/s with the maximum of 4.5 m/s. It was found that additional fin significantly increase the ability of Savonius rotor VAWT to generate electrical energy shown by increasing of electrical power. The highest power generated is 13.40 Watt at a wind speed of 4.5 m/s by adding 1 (one) fin in the blade. It increased by 22.71% from the rotor blade with no additional fin. However, increasing number of fins in the blade was not linearly increase the electrical power generated. The wind rotor blade with 4 additional fins is indicated has the lowest performance, generating only 10.80 Watt electrical power, accounted lower than the one generated by no fin-rotor blade. By knowing the effect of the rotor shape, the rotor dimension, the addition of fin, transmission, and generator used, it is possible to determine alternative geometry design in increasing the electrical power generated by Savonius wind turbine.

Biomechanical model of batoid (skates and rays) pectoral fins predicts the influence of skeletal structure on fin kinematics: implications for bio-inspired design.

PubMed

Russo, R S; Blemker, S S; Fish, F E; Bart-Smith, H

2015-06-16

Growing interest in the development of bio-inspired autonomous underwater vehicles (AUVs) has motivated research in understanding the mechanisms behind the propulsion systems of marine animals. For example, the locomotive behavior of rays (Batoidea) by movement of the pectoral fins is of particular interest due to their superior performance characteristics over contemporary AUV propulsion systems. To better understand the mechanics of pectoral fin propulsion, this paper introduces a biomechanical model that simulates how batoid skeletal structures function to achieve the swimming locomotion observed in nature. Two rays were studied, Dasyatis sabina (Atlantic ray), and Rhinoptera bonasus (cownose ray). These species were selected because they exhibit very different swimming styles (undulation versus oscillation), but all use primarily their pectoral fins for propulsion (unlike electric rays or guitarfishes). Computerized tomography scans of each species were taken to image the underlying structure, which reveal a complex system of cartilaginous joints and linkages. Data collected from these images were used to quantify the complete skeletal morphometry of each batoid fin. Morphological differences were identified in the internal cartilage arrangement between each species including variations in the orientation of the skeletal elements, or radials, and the joint patterns between them, called the inter-radial joint pattern. These data were used as the primary input into the biomechanical model to couple a given ray skeletal structure with various swimming motions. A key output of the model is an estimation of the uniaxial strain that develops in the skeletal connective tissue in order for the structure to achieve motions observed during swimming. Tensile load tests of this connective tissue were conducted to further investigate the implications of the material strain predictions. The model also demonstrates that changes in the skeletal architecture (e.g., joint

Phenotypic variation in dorsal fin morphology of coastal bottlenose dolphins (Tursiops truncatus) off Mexico

PubMed Central

Rocha-Olivares, Axayácatl; Morteo, Rodrigo; Weller, David W.

2017-01-01

Geographic variation in external morphology is thought to reflect an interplay between genotype and the environment. Morphological variation has been well-described for a number of cetacean species, including the bottlenose dolphin (Tursiops truncatus). In this study we analyzed dorsal fin morphometric variation in coastal bottlenose dolphins to search for geographic patterns at different spatial scales. A total of 533 dorsal fin images from 19 available photo-identification catalogs across the three Mexican oceanic regions (Pacific Ocean n = 6, Gulf of California n = 6 and, Gulf of Mexico n = 7) were used in the analysis. Eleven fin shape measurements were analyzed to evaluate fin polymorphism through multivariate tests. Principal Component Analysis on log-transformed standardized ratios explained 94% of the variance. Canonical Discriminant Function Analysis on factor scores showed separation among most study areas (p < 0.05) with exception of the Gulf of Mexico where a strong morphometric cline was found. Possible explanations for the observed differences are related to environmental, biological and evolutionary processes. Shape distinction between dorsal fins from the Pacific and those from the Gulf of California were consistent with previously reported differences in skull morphometrics and genetics. Although the functional advantages of dorsal fin shape remains to be assessed, it is not unlikely that over a wide range of environments, fin shape may represent a trade-off among thermoregulatory capacity, hydrodynamic performance and the swimming/hunting behavior of the species. PMID:28626607

Differentiation of chondrocytes and scleroblasts during dorsal fin skeletogenesis in flounder larvae.

PubMed

Suzuki, Tohru; Haga, Yutaka; Takeuchi, Toshio; Uji, Susumu; Hashimoto, Hisashi; Kurokawa, Tadahide

2003-01-01

In teleosts, the embryonic fin fold consists of a peridermis, an underlying epidermis and a small number of mesenchymal cells. Beginning from such a simple structure, the fin skeletons, including the proximal and distal radials and lepidotrichia (finrays), develop in the dorsal fin fold at the larval stage. Their process of skeletogenesis and embryonic origin are unclear. Using flounder larvae, we report the differentiation process for chondrocytes and scleroblasts prior to fin skeletogenesis and the effects of retinoic acid (RA) on it. In early larvae, the mesenchymal cells grow between the epidermis and spinal cord to form a line of periodical condensations, which are proximal radial primordia, to produce chondrocytes. The prescleroblasts, which ossify the proximal radial cartilages, differentiate in the mesenchymal cells remaining between the cartilages. Then, mesenchymal condensations occur between the distal ends of the proximal radials, forming distal radial primordia, to produce chondrocytes. Simultaneously, condensations occur between the distal radial primordia and peridermis, which are lepidotrichia primordia, to produce prescleroblasts. Exogenous RA specifically inhibits the mesenchymal condensation prior to the proximal radial formation together with the down-regulation of sonic hedgehog (shh) and patched (pta) expression, resulting in the loss of proximal radials. Thus, it was indicated that differentiation of the precursor cells of radials and lepidotrichia begins in the proximal part of the fin fold and that the initial mesenchymal condensation prior to the proximal radial formation is highly susceptible to the effects of RA. Lepidotrichia formation does not occur where proximal radials are absent, indicating that lepidotrichia differentiation requires interaction with the radial cartilages. To examine the suggestion that neural crest cells contribute to the medial fin skeletons, we localized the HNK-1 positive cells in flounder embryos and slug and

Conical similarity of shock/boundary layer interactions generated by swept fins

NASA Technical Reports Server (NTRS)

Lu, F. K.; Settles, G. S.

1983-01-01

A parametric experimental study has been made of the class of 3D shock wave/turbulent boundary layer interactions generated by swept-leading-edge fins. The fin sweepback angles ranged from 0 to 65 deg at angles of attack of 5, 9, and 15 deg. Two equilibrium 2D turbulent boundary layers with a free-stream Mach number of 2.95 and a Reynolds number of 6.3 x 10 to the 7th/m were used as incoming flow conditions. All the resulting interactions were found to possess conical symmetry of surface pressures and skin friction lines beyond an initial inception zone. Further, these interactions revealed a simple similarity based on inviscid shock strength irrespective of fin sweepback or angle of attack.

Experimental investigation of heat transfer and flow pattern from heated horizontal rectangular fin array under natural convection

NASA Astrophysics Data System (ADS)

Taji, S. G.; Parishwad, G. V.; Sane, N. K.

2014-07-01

This paper presents results of the experimental study conducted on heated horizontal rectangular fin array under natural convection. The temperature mapping and the prediction of the flow patterns over the fin array with variable fin spacing is carried out. Dimensionless fin spacing to height (S/H) ratio is varied from 0.05 to 0.3 and length to height ratio (L/H) = 5 is kept constant. The heater input to the fin array assembly is varied from 25 to 100 W. The single chimney flow pattern is observed from 8 to 12 mm fin spacing. The end flow is choked below 6 mm fin spacing. The single chimney flow pattern changes to sliding or end flow choking at 6 mm fin spacing. The average heat transfer coefficient (ha) is very small (2.52-5.78 W/m2 K) at 100 W for S = 5-12 mm. The ha is very small (1.12-1.8 W/m2 K) at 100 W for 2-4 mm fin spacing due to choked fin array end condition. The end flow is not sufficient to reach up to central portion of fin array and in the middle portion there is an unsteady down and up flow pattern resulting in sliding chimney. The central bottom portion of fin array channel does not contribute much in heat dissipation for S = 2-4 mm. The ha has significantly improved at higher spacing as compared to lower spacing region. The single chimney flow pattern is preferred from heat transfer point of view. The optimum spacing is confirmed in the range of 8-10 mm. The average heat transfer results are compared with previous literature and showed similar trend and satisfactory agreement. An empirical equation has been proposed to correlate the average Nusselt number as a function of Grashof number and fin spacing to height ratio. The average error for this equation is -0.32 %.

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

NASA Astrophysics Data System (ADS)

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.

AUV Positioning Method Based on Tightly Coupled SINS/LBL for Underwater Acoustic Multipath Propagation.

PubMed

Zhang, Tao; Shi, Hongfei; Chen, Liping; Li, Yao; Tong, Jinwu

2016-03-11

This paper researches an AUV (Autonomous Underwater Vehicle) positioning method based on SINS (Strapdown Inertial Navigation System)/LBL (Long Base Line) tightly coupled algorithm. This algorithm mainly includes SINS-assisted searching method of optimum slant-range of underwater acoustic propagation multipath, SINS/LBL tightly coupled model and multi-sensor information fusion algorithm. Fuzzy correlation peak problem of underwater LBL acoustic propagation multipath could be solved based on SINS positional information, thus improving LBL positional accuracy. Moreover, introduction of SINS-centered LBL locating information could compensate accumulative AUV position error effectively and regularly. Compared to loosely coupled algorithm, this tightly coupled algorithm can still provide accurate location information when there are fewer than four available hydrophones (or within the signal receiving range). Therefore, effective positional calibration area of tightly coupled system based on LBL array is wider and has higher reliability and fault tolerance than loosely coupled. It is more applicable to AUV positioning based on SINS/LBL.

AUV Positioning Method Based on Tightly Coupled SINS/LBL for Underwater Acoustic Multipath Propagation

PubMed Central

Zhang, Tao; Shi, Hongfei; Chen, Liping; Li, Yao; Tong, Jinwu

2016-01-01

This paper researches an AUV (Autonomous Underwater Vehicle) positioning method based on SINS (Strapdown Inertial Navigation System)/LBL (Long Base Line) tightly coupled algorithm. This algorithm mainly includes SINS-assisted searching method of optimum slant-range of underwater acoustic propagation multipath, SINS/LBL tightly coupled model and multi-sensor information fusion algorithm. Fuzzy correlation peak problem of underwater LBL acoustic propagation multipath could be solved based on SINS positional information, thus improving LBL positional accuracy. Moreover, introduction of SINS-centered LBL locating information could compensate accumulative AUV position error effectively and regularly. Compared to loosely coupled algorithm, this tightly coupled algorithm can still provide accurate location information when there are fewer than four available hydrophones (or within the signal receiving range). Therefore, effective positional calibration area of tightly coupled system based on LBL array is wider and has higher reliability and fault tolerance than loosely coupled. It is more applicable to AUV positioning based on SINS/LBL. PMID:26978361

Numerical analysis on interactions between fluid flow and structure deformation in plate-fin heat exchanger by Galerkin method

NASA Astrophysics Data System (ADS)

Liu, Jing-cheng; Wei, Xiu-ting; Zhou, Zhi-yong; Wei, Zhen-wen

2018-03-01

The fluid-structure interaction performance of plate-fin heat exchanger (PFHE) with serrated fins in large scale air-separation equipment was investigated in this paper. The stress and deformation of fins were analyzed, besides, the interaction equations were deduced by Galerkin method. The governing equations of fluid flow and heat transfer in PFHE were deduced by finite volume method (FVM). The distribution of strain and stress were calculated in large scale air separation equipment and the coupling situation of serrated fins under laminar situation was analyzed. The results indicated that the interactions between fins and fluid flow in the exchanger have significant impacts on heat transfer enhancement, meanwhile, the strain and stress of fins includes dynamic pressure of the sealing head and flow impact with the increase of flow velocity. The impacts are especially significant at the conjunction of two fins because of the non-alignment fins. It can be concluded that the soldering process and channel width led to structure deformation of fins in the exchanger, and degraded heat transfer efficiency.

Recent Improvements to the Finite-Fault Rupture Detector Algorithm: FinDer II

NASA Astrophysics Data System (ADS)

Smith, D.; Boese, M.; Heaton, T. H.

2015-12-01

Constraining the finite-fault rupture extent and azimuth is crucial for accurately estimating ground-motion in large earthquakes. Detecting and modeling finite-fault ruptures in real-time is thus essential to both earthquake early warning (EEW) and rapid emergency response. Following extensive real-time and offline testing, the finite-fault rupture detector algorithm, FinDer (Böse et al., 2012 & 2015), was successfully integrated into the California-wide ShakeAlert EEW demonstration system. Since April 2015, FinDer has been scanning real-time waveform data from approximately 420 strong-motion stations in California for peak ground acceleration (PGA) patterns indicative of earthquakes. FinDer analyzes strong-motion data by comparing spatial images of observed PGA with theoretical templates modeled from empirical ground-motion prediction equations (GMPEs). If the correlation between the observed and theoretical PGA is sufficiently high, a report is sent to ShakeAlert including the estimated centroid position, length, and strike, and their uncertainties, of an ongoing fault rupture. Rupture estimates are continuously updated as new data arrives. As part of a joint effort between USGS Menlo Park, ETH Zurich, and Caltech, we have rewritten FinDer in C++ to obtain a faster and more flexible implementation. One new feature of FinDer II is that multiple contour lines of high-frequency PGA are computed and correlated with templates, allowing the detection of both large earthquakes and much smaller (~ M3.5) events shortly after their nucleation. Unlike previous EEW algorithms, FinDer II thus provides a modeling approach for both small-magnitude point-source and larger-magnitude finite-fault ruptures with consistent error estimates for the entire event magnitude range.

A Novel Grid SINS/DVL Integrated Navigation Algorithm for Marine Application

PubMed Central

Kang, Yingyao; Zhao, Lin; Cheng, Jianhua; Fan, Xiaoliang

2018-01-01

Integrated navigation algorithms under the grid frame have been proposed based on the Kalman filter (KF) to solve the problem of navigation in some special regions. However, in the existing study of grid strapdown inertial navigation system (SINS)/Doppler velocity log (DVL) integrated navigation algorithms, the Earth models of the filter dynamic model and the SINS mechanization are not unified. Besides, traditional integrated systems with the KF based correction scheme are susceptible to measurement errors, which would decrease the accuracy and robustness of the system. In this paper, an adaptive robust Kalman filter (ARKF) based hybrid-correction grid SINS/DVL integrated navigation algorithm is designed with the unified reference ellipsoid Earth model to improve the navigation accuracy in middle-high latitude regions for marine application. Firstly, to unify the Earth models, the mechanization of grid SINS is introduced and the error equations are derived based on the same reference ellipsoid Earth model. Then, a more accurate grid SINS/DVL filter model is designed according to the new error equations. Finally, a hybrid-correction scheme based on the ARKF is proposed to resist the effect of measurement errors. Simulation and experiment results show that, compared with the traditional algorithms, the proposed navigation algorithm can effectively improve the navigation performance in middle-high latitude regions by the unified Earth models and the ARKF based hybrid-correction scheme. PMID:29373549

Experimental Investigation on Heat Transfer Characteristics of Different Metallic Fin Arrays

NASA Astrophysics Data System (ADS)

Sangewar, Ravi Kumar

2018-04-01

The reliability of electronic equipment depends on the reliability of the system. For small applications natural convection cooling is sufficient, but for the electronic equipment having number of heat generating components, forced convection cooling is essential. In number of cases, pin fin arrangement is preferred for augmentation of heat transfer. Here, the performance of pin fin array of copper and aluminum material with in-line, as well as staggered arrangement over a flat plate is studied. Constant heat input was given to the inline, staggered arrangement of copper as well as aluminium pin fin arrays. In the present experimental study, heat input and airflow rates are the variables. It was found that the heat transfer coefficient for staggered array is 15% more than that of the in-line array, at the same time pressure drop across the staggered array is more by 10% than the in-line array. The pressure drop was observed to be increasing with increase in flow rate as expected. Endeavor of the present work is to find the optimum spacing between the fins in an array for maximum heat transfer rate, by investigating the heat transfer characteristics.

The effect of diet on dorsal fin erosion in steelhead trout (Oncorhynchus mykiss)

USGS Publications Warehouse

Lellis, W.A.; Barrows, F.T.

1997-01-01

A 2 X 2 factorial experiment of diet type (krill vs. fish meal) and steroid supplementation (0 vs. 30 ??g 17??-methyltestosterone kg-1) was conducted to determine the effects on dorsal fin erosion in steelhead trout. Triplicate tanks of 250 fry were fed one of the four diets at a rate calculated to produce 115 g fish in 34 weeks. Fish were transferred to larger tanks when mean density index reached 0.40. Dorsal fin index (DFI, measured as mean dorsal fin height X 100/total fish length) was greater (P < 0.001) among fish fed krill-based diets than for fish fed fish-based diets at weeks 12, 22, and 34 of the trial. Added testosterone decreased (p = 0.04) DFI among fish fed the krill diet at week 12 but otherwise had no effect on fin condition. Addition of testosterone to either diet type decreased (P = 0.02) critical thermal maximum, which is a measure of fish resistance to thermal stress. The results suggest that diet composition can influence the rate of dorsal fin erosion in steelhead trout through a metabolic, behavioral, or combined change.

Habitat of calling blue and fin whales in the Southern California Bight

NASA Astrophysics Data System (ADS)

Sirovic, A.; Chou, E.; Roch, M. A.

2016-02-01

Northeast Pacific blue whale B calls and fin whale 20 Hz calls were detected from passive acoustic data collected over seven years at 16 sites in the Southern California Bight (SCB). Calling blue whales were most common in the coastal areas, during the summer and fall months. Fin whales began calling in fall and continued through winter, in the southcentral SCB. These data were used to develop habitat models of calling blue and fin whales in areas of high and low abundance in the SCB, using remotely sensed variables such as sea surface temperature, sea surface height, chlorophyll a, and primary productivity as model covariates. A random forest framework was used for variable selection and generalized additive models were developed to explain functional relationships, evaluate relative contribution of each significant variable, and investigate predictive abilities of models of calling whales. Seasonal component was an important feature of all models. Additionally, areas of high calling blue and fin whale abundance both had a positive relationship with the sea surface temperature. In areas of lower abundance, chlorophyll a concentration and primary productivity were important variables for blue whale models and sea surface height and primary productivity were significant covariates in fin whale models. Predictive models were generally better for predicting general trends than absolute values, but there was a large degree of variation in year-to-year predictability across different sites.

Development and Evolution of the Muscles of the Pelvic Fin

PubMed Central

Cole, Nicholas J.; Hall, Thomas E.; Don, Emily K.; Berger, Silke; Boisvert, Catherine A.; Neyt, Christine; Ericsson, Rolf; Joss, Jean; Gurevich, David B.; Currie, Peter D.

2011-01-01

Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition. PMID:21990962

The sexually dimorphic adipose fin is an androgen target tissue in the brown trout (Salmo trutta fario).

PubMed

Hisar, Olcay; Sönmez, Adem Yavuz; Hisar, Şükriye Aras; Budak, Harun; Gültepe, Nejdet

2013-04-01

An investigation has been described on the relationship of body length, age and sex with adipose fin length and the number of androgen receptor (AR)-containing cells in the adipose fin as a secondary sexual characteristic for brown trout (Salmo trutta fario). Firstly, body and adipose fin lengths of 2- to 5-year-old brown trout were measured. Thereafter, these fish were killed by decapitation, then their sexes were determined, and adipose fins were excised. The cellular bases of AR binding activities in the adipose fins were analyzed with an antibody against human/rat AR peptide. Immunocytochemistry and western blotting techniques were performed with this antibody. Analysis of morphological measurements indicated that body length and age had a linear relationship with adipose fin length. The coefficients of determination for the body length and age were 0.92 and 0.85 in the male fish and 0.76 and 0.73 in the female fish against the adipose fin length, respectively. At 2 years of age, cells in the adipose fin did not exhibit AR immunoreactivity. However, AR-immunopositive cells were abundant in the adipose fin of 3- to 5-year-old fish. Moreover, the number of AR-immunopositive cells was significantly (P < 0.05) high in males and increased with age. These observations indicate that the adipose fin in the brown trout is a probable target for androgen action and that tissue function or development may to some extent be androgen dependent. In addition, it is likely that such an effect will be mediated by specific androgen receptors.

Epigenetic activation of SIN1 promotes NSCLC cell proliferation and metastasis by affecting the epithelial–mesenchymal transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Zhongwu; Wang, Yaqin; Wang, Yuemei

Stress-activated protein kinase (SAPK) interacting protein 1 (SIN1) is an essential component of mTORC2. Previous studies have shown that SIN1 is a key regulator of Akt pathway which plays an important role in various pathological conditions including cancer. While its effects and mechanisms on the progression of NSCLC remain unknown. In this study, we report that SIN1 is able to promote the growth and migration of NSCLC cells both in vitro and in vivo. Overexpression of SIN1 promoted A549 and H1299 cells proliferation by both MTT and colony formation assays. Consistently, knockdown of SIN1 inhibited the proliferation of these cells. In transwell assay,more » overexpression of SIN1 increased the migration of A549 and H1299 cells, while SIN1 knockdown reduced their migration. In a tumor xenograft model, overexpression of SIN1 promoted tumor growth of A549 cells in vivo, while SIN1 knockdown suppresses the tumor growth. We also found a mechanistic link between SIN1 and H3K4me3, H3K4me3 is involved in SIN1 upregulation. Moreover, SIN1 can significantly promote the in vitro migration and invasion of NSCLC cells via induction epithelial mesenchymal transition (EMT) process, which subsequently leads to transcriptional downregulation of epithelial marker E-cadherin and upregulation of mesenchymal markers N-cadherin and Vimentin expression. Together, our results reveal that SIN1 plays an important role in NSCLC and SIN1 is a potential biomarker and a promising target in the treatment of NSCLC.« less

Evidence for the secondary sexual development of the anal fin in female kokanee salmon Oncorhynchus nerka.

PubMed

Thorn, M W; Morbey, Y E

2016-02-01

This study examines whether the anal fin undergoes secondary sexual development similar to other reproductive traits in salmonids. This hypothesis was tested by comparing the anal-fin size of female kokanee salmon Oncorhynchus nerka that were in the early and late stages of sexual development. Females in an advanced stage of maturation had significantly larger anal fins relative to females in an early state of maturation (+4-7%), indicating that the anal fin undergoes secondary sexual development. The magnitude of this secondary growth was comparable with snout length (+9-10%), which is known to undergo secondary sexual development in female salmonids. When morphological trait dimensions were compared between the sexes, the anal fin was the only morphological trait found to have a female-biased sexual size dimorphism. This is the first study to show that the anal fin of female salmonids undergoes secondary sexual development. © 2015 The Fisheries Society of the British Isles.

Effects of Tube Diameter and Tubeside Fin Geometry on the Heat Transfer Performance of Air-Cooled Condensers

NASA Astrophysics Data System (ADS)

Wang, H. S.; Honda, Hiroshi

A theoretical study has been made on the effects of tube diameter and tubeside fin geometry on the heat transfer performance of air-cooled condensers. Extensive numerical calculations of overall heat transfer from refrigerant R410A flowing inside a horizontal microfin tube to ambient air were conducted for a typical operating condition of the air-cooled condenser. The tubeside heat transfer coefficient was calculated by applying a modified stratified flow model developed by Wang et al.8). The numerical results show that the effects of tube diameter, fin height, fin number and helix angle of groove are significant, whereas those of the width of flat portion at the fin tip, the radius of round corner at the fin tip and the fin half tip angle are small.

Chromatin associated Sin3A is essential for male germ cell lineage in the mouse

PubMed Central

Pellegrino, Jessica; Castrillon, Diego H.; David, Gregory

2012-01-01

Spermatogenesis is a complex process that requires coordinated proliferation and differentiation of male germ cells. The molecular events that dictate this process are largely unknown, but are likely to involve highly regulated transcriptional control. In this study, we investigate the contribution of chromatin associated Sin3A in mouse germ cell lineage development. Genetic inactivation of Sin3A in the male germline leads to sterility that results from the early and penetrant apoptotic death observed in Sin3A-deleted germ cells, coincident with the reentry in mitosis. Sin3A-deleted testes exhibit a Sertoli-cell only phenotype, consistent with the absolute requirement for Sin3A in germ cells’ development and/or viability. Interestingly, transcripts analysis revealed that the expression program of Sertoli cells is altered upon inactivation of Sin3A in germ cells. These studies identified a central role for the mammalian Sin3-HDAC complex in the germ cell lineage, and point to an exquisite transcriptional crosstalk between germ cells and their niche to support fertility in mammals. PMID:22820070

Approximation properties of Fejér- and de la Valleé-Poussin-type means for partial sums of a special series in the system \\{\\sin x\\sin kx\\}_{k=1}^\\infty

NASA Astrophysics Data System (ADS)

Sharapudinov, I. I.

2015-04-01

This paper is concerned with series of the form \\displaystyle Φ(θ)=A_Φ(θ)+\\sinθ\\sumk=1^∞\\varphi_k\\sin kθ, where Φ(θ) is an even 2π-periodic function with finite values Φ(0) and Φ(π), \\displaystyle A_Φ(θ)=\\frac{Φ(0)+Φ(π)}{2}+\\frac{Φ(0)-Φ(π)}{2}\\cosθ,\\qquad\\varphi(θ)=Φ(θ)-A_Φ(θ), \\displaystyle \\varphi_k=\\frac{2}π\\int_0^π\\varphi(t)\\frac{\\sin kt}{\\sin t} dt. Series of this type appear as a particular case of more general special series in ultraspherical Jacobi polynomials, which were first introduced and studied by the author. Partial sums of the form \\Pi_n(Φ)=\\Pi_n(Φ,θ)=A_Φ(θ)+\\sinθ\\sumk=1n-1\\varphi_k\\sin kθ are shown to have a number of important properties, which give them an advantage over trigonometric Fourier sums of the form S_n(Φ,θ)=\\frac{a_0}{2}+\\sumk=1^na_k\\cos kθ. Approximation properties of Fejér- and de la Valleé-Poussin-type means for the partial sums \\Pi_n(Φ,θ) are studied. Bibliography: 7 titles.

Aeroservoelastic DAP missile fin development. [directionally attached piezoelectric actuator

NASA Technical Reports Server (NTRS)

Barrett, Ron

1993-01-01

The development of an active aeroservoelastic missile fin using directionally attached piezoelectric (DAP) actuator elements is detailed. Several different types of actuator elements are examined, including piezoelectric polymers, piezoelectric fiber composites, and conventionally attached piezoelectric (CAP) and DAP elements. These actuator elements are bonded to the substrate of a torque plate. The root of the torque plate is attached to a fuselage hard point or folding pivot. The tip of the plate is bonded to an aerodynamic shell which undergoes a pitch change as the plate twists. The design procedures used on the plate are discussed. A comparison of the various actuator element shows that DAP elements provide the highest deflections with the highest torsional stiffness. A torque plate was constructed from 0.2032 mm thick DAP elements bonded to a 0.127 mm thick AISI 1010 steel substrate. The torque plate produced static twist deflections in excess of +/- 3 deg. An aerodynamic shell with a modified NACA 0012 profile was added to the torque plate. This fin was tested in a wind tunnel at speeds up to 50 ms/sec. The static deflection of the fin was predicted to within 6 percent of the experimental data.

FinFET memory cell improvements for higher immunity against single event upsets

NASA Astrophysics Data System (ADS)

Sajit, Ahmed Sattar

The 21st century is witnessing a tremendous demand for transistors. Life amenities have incorporated the transistor in every aspect of daily life, ranging from toys to rocket science. Day by day, scaling down the transistor is becoming an imperious necessity. However, it is not a straightforward process; instead, it faces overwhelming challenges. Due to these scaling changes, new technologies, such as FinFETs for example, have emerged as alternatives to the conventional bulk-CMOS technology. FinFET has more control over the channel, therefore, leakage current is reduced. FinFET could bridge the gap between silicon devices and non-silicon devices. The semiconductor industry is now incorporating FinFETs in systems and subsystems. For example, Intel has been using them in their newest processors, delivering potential saving powers and increased speeds to memory circuits. Memory sub-systems are considered a vital component in the digital era. In memory, few rows are read or written at a time, while the most rows are static; hence, reducing leakage current increases the performance. However, as a transistor shrinks, it becomes more vulnerable to the effects from radioactive particle strikes. If a particle hits a node in a memory cell, the content might flip; consequently, leading to corrupting stored data. Critical fields, such as medical and aerospace, where there are no second chances and cannot even afford to operate at 99.99% accuracy, has induced me to find a rigid circuit in a radiated working environment. This research focuses on a wide spectrum of memories such as 6T SRAM, 8T SRAM, and DICE memory cells using FinFET technology and finding the best platform in terms of Read and Write delay, susceptibility level of SNM, RSNM, leakage current, energy consumption, and Single Event Upsets (SEUs). This research has shown that the SEU tolerance that 6T and 8T FinFET SRAMs provide may not be acceptable in medical and aerospace applications where there is a very high

Design and Analyze a New Measuring Lift Device for Fin Stabilizers Using Stiffness Matrix of Euler-Bernoulli Beam

PubMed Central

Liang, Lihua; Sun, Mingxiao; Shi, Hongyu; Luan, Tiantian

2017-01-01

Fin-angle feedback control is usually used in conventional fin stabilizers, and its actual anti-rolling effect is difficult to reach theoretical design requirements. Primarily, lift of control torque is a theoretical value calculated by static hydrodynamic characteristics of fin. However, hydrodynamic characteristics of fin are dynamic while fin is moving in waves. As a result, there is a large deviation between actual value and theoretical value of lift. Firstly, the reasons of deviation are analyzed theoretically, which could avoid a variety of interference factors and complex theoretical derivations. Secondly, a new device is designed for direct measurement of actual lift, which is composed of fin-shaft combined mechanism and sensors. This new device can make fin-shaft not only be the basic function of rotating fin, but also detect actual lift. Through analysis using stiffness matrix of Euler-Bernoulli beam, displacement of shaft-core end is measured instead of lift which is difficult to measure. Then quantitative relationship between lift and displacement is defined. Three main factors are analyzed with quantitative relationship. What is more, two installation modes of sensors and a removable shaft-end cover are proposed according to hydrodynamic characteristics of fin. Thus the new device contributes to maintenance and measurement. Lastly, the effectiveness and accuracy of device are verified by contrasting calculation and simulation on the basis of actual design parameters. And the new measuring lift method can be proved to be effective through experiments. The new device is achieved from conventional fin stabilizers. Accordingly, the reliability of original equipment is inherited. The alteration of fin stabilizers is minor, which is suitable for engineering application. In addition, the flexural properties of fin-shaft are digitized with analysis of stiffness matrix. This method provides theoretical support for engineering application by carrying out finite

Hsp47 mediates Cx43-dependent skeletal growth and patterning in the regenerating fin.

PubMed

Bhadra, Joyita; Iovine, M Kathryn

2015-11-01

Skeletal morphogenesis describes how bones achieve their correct shape and size and appropriately position joints. We use the regenerating caudal fin of zebrafish to study this process. Our examination of the fin length mutant short fin (sof (b123)) has revealed that the gap junction protein Cx43 is involved in skeletal morphogenesis by promoting cell proliferation and inhibiting joint formation, thereby coordinating skeletal growth and patterning. Here we demonstrate that serpinh1b is molecularly and functionally downstream of cx43. The gene serpinh1b codes for a protein called Hsp47, a molecular chaperone responsible for proper folding of procollagen molecules. Knockdown of Hsp47 in regenerating fins recapitulates the sof (b123) phenotypes of reduced fin length, reduced segment length and reduced level of cell proliferation. Furthermore, Hsp47 knockdown affects the organization and localization of the collagen-based actinotrichia. Together, our findings reveal that serpinh1b acts in a cx43 dependent manner to regulate cell proliferation and joint formation. We conclude that disruption of the collagen-based extracellular matrix influences signaling events required for cell proliferation, as well as the patterning of skeletal precursor cells that influences segment length. Therefore, we suggest that Hsp47 function is necessary for skeletal growth and patterning during fin regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Estimating ages of Utah chubs by use of pectoral fin rays, otoliths, and scales

USGS Publications Warehouse

Griffin, Kayla M; Beard, Zachary S.; Flinders, John M.; Quist, Michael C.

2017-01-01

Utah chub Gila atraria is native to the Upper Snake River system in Wyoming and Idaho and to the Lake Bonneville Basin in Utah and southeastern Idaho. However, the Utah chub has been introduced into many other waterbodies in the western United States, where it competes with ecologically and economically important species. The objectives of this study were to evaluate between-reader precision and reader confidence in age estimates obtained from pectoral fin rays, lapilli (otoliths), asterisci (otoliths), and scales for Utah chubs collected from Henrys Lake, Idaho. Lapilli have been previously shown to provide accurate age estimates for Utah chubs; therefore, we sought to compare age estimates from fin rays, asterisci, and scales to those from lapilli. The between-reader coefficient of variation (CV) in age estimates was lowest and the percent of exact reader agreement (PA-0) was highest for pectoral fin rays (CV = 4.7, PA-0 = 74%), followed by scales (CV = 10.3, PA-0 = 52.3%), lapilli (CV = 11.6, PA-0 = 48.2%), and asterisci (CV = 13.0, PA-0 = 41.7%). Consensus age estimates from pectoral fin rays showed high concordance with consensus age estimates from lapilli. Our results indicate that pectoral fin rays provide the most precise age estimates for Utah chub. Pectoral fin rays are easily collected and processed and also provide age estimates without requiring fish sacrifice.

Local Heat Transfer for Finned-Tube Heat Exchangers using Oval Tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, James Edward; Sohal, Manohar Singh

2000-08-01

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with either a circular tube or an elliptical tube in crossflow. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally appliedmore » one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.56 x 10-3 to 15.6 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 630 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. The elliptical tube had an aspect ratio of 3:1 and a/H equal to 4.33. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of circular and oval tubes and their relationship to the complex horseshoe vortex system that forms in the flow stagnation region. Fin surface stagnation-region Nusselt numbers are shown to be proportional to the square-root of Reynolds number.« less

Specific requirement of the chromatin modifier mSin3B in cell cycle exit and cellular differentiation

PubMed Central

David, Gregory; Grandinetti, Kathryn B.; Finnerty, Patricia M.; Simpson, Natalie; Chu, Gerald C.; DePinho, Ronald A.

2008-01-01

The Sin3-histone deacetylase (HDAC) corepressor complex is conserved from yeast to humans. Mammals possess two highly related Sin3 proteins, mSin3A and mSin3B, which serve as scaffolds tethering HDAC enzymatic activity, and numerous sequence-specific transcription factors to enable local chromatin regulation at specific gene targets. Despite broad overlapping expression of mSin3A and mSin3B, mSin3A is cell-essential and vital for early embryonic development. Here, genetic disruption of mSin3B reveals a very different phenotype characterized by the survival of cultured cells and lethality at late stages of embryonic development with defective differentiation of multiple lineages—phenotypes that are strikingly reminiscent of those associated with loss of retinoblastoma family members or E2F transcriptional repressors. Additionally, we observe that, whereas mSin3B−/− cells cycle normally under standard growth conditions, they show an impaired ability to exit the cell cycle with limiting growth factors. Correspondingly, mSin3B interacts physically with the promoters of known E2F target genes, and its deficiency is associated with derepression of these gene targets in vivo. Together, these results reveal a critical role for mSin3B in the control of cell cycle exit and terminal differentiation in mammals and establish contrasting roles for the mSin3 proteins in the growth and development of specific lineages. PMID:18332431

Measurement of sin2θw and ϱ in deep inelastic neutrino-nucleon scattering

NASA Astrophysics Data System (ADS)

Reutens, P. G.; Merritt, F. S.; Macfarlane, D. B.; Messner, R. L.; Novikoff, D. B.; Purohit, M. V.; Blair, R. E.; Sciulli, F. J.; Shaevitz, M. H.; Fisk, H. E.; Fukushima, Y.; Jin, B. N.; Kondo, T.; Rapidis, P. A.; Yovanovitch, D. D.; Bodek, A.; Coleman, R. N.; Marsh, W. L.; Fackler, O. D.; Jenkins, K. A.

1985-03-01

We describe a high statistics measurement from deep inelastic neutrino-nucleon scattering of the electroweak parameters ϱ and sin2θw, performed in the Fermilab narrow-band neutrino beam. Our measurement uses a radius-dependent cut in y = EH/Ev which reduces the systematic error in sin2θw, and incorporates electromagnetic and electroweak radiative corrections. In a renormalization scheme where sin2θw ≡ 1-m2W/m2Z, a value of sin2θw = 0.242+/-0.011+/-0.005 is obtained fixing ϱ = 1. If both sin2θw and ϱ are allowed to vary in a fit to our data, we measure ϱ = 0.991 +/- 0.025 +/- 0.009. Present address: IBM Thomas J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598, USA.

Comparison of the precision of age estimates generated from fin rays, scales, and otoliths of Blue Sucker

USGS Publications Warehouse

Acre, Matthew R.; Alejandrez, Celeste; East, Jessica; Massure, Wade A.; Miyazono, S.; Pease, Jessica E.; Roesler, Elizabeth L.; Williams, H.M.; Grabowski, Timothy B.

2017-01-01

Evaluating the precision of age estimates generated by different readers and different calcified structures is an important part of generating reliable estimations of growth, recruitment, and mortality for fish populations. Understanding the potential loss of precision associated with using structures harvested without sacrificing individuals, such as scales or fin rays, is particularly important when working with imperiled species, such as Cycleptus elongatus (Blue Sucker). We collected otoliths (lapilli), scales, and the first fin rays of the dorsal, anal, pelvic, and pectoral fins of 9 Blue Suckers. We generated age estimates from each structure by both experienced (n = 5) and novice (n = 4) readers. We found that, independent of the structure used to generate the age estimates, the mean coefficient of variation (CV) of experienced readers was approximately 29% lower than that of novice readers. Further, the mean CV of age estimates generated from pectoral-fin rays, pelvic-fin rays, and scales were statistically indistinguishable and less than those of dorsal-fin rays, anal-fin rays, and otoliths. Anal-, dorsal-, and pelvic-fin rays and scales underestimated age compared to otoliths, but age estimates from pectoral-fin rays were comparable to those from otoliths. Skill level, structure, and fish total-length influenced reader precision between subsequent reads of the same aging structure from a particular fish. Using structures that can be harvested non-lethally to estimate the age of Blue Sucker can provide reliable and reproducible results, similar to those that would be expected from using otoliths. Therefore, we recommend the use of pectoral-fin rays as a non-lethal method to obtain age estimates for Blue Suckers.

Genetic Architecture of the Variation in Male-Specific Ossified Processes on the Anal Fins of Japanese Medaka.

PubMed

Kawajiri, Maiko; Fujimoto, Shingo; Yoshida, Kohta; Yamahira, Kazunori; Kitano, Jun

2015-10-28

Traits involved in reproduction evolve rapidly and show great diversity among closely related species. However, the genetic mechanisms that underlie the diversification of courtship traits are mostly unknown. Japanese medaka fishes (Oryzias latipes) use anal fins to attract females and to grasp females during courtship; the males have longer anal fins with male-specific ossified papillary processes on the fin rays. However, anal fin morphology varies between populations: the southern populations tend to have longer anal fins and more processes than the northern populations. In the present study, we conducted quantitative trait locus (QTL) mapping to investigate the genetic architecture underlying the variation in the number of papillary processes of Japanese medaka fish and compared the QTL with previously identified QTL controlling anal fin length. First, we found that only a few QTL were shared between anal fin length and papillary process number. Second, we found that the numbers of papillary processes on different fin rays often were controlled by different QTL. Finally, we produced another independent cross and found that some QTL were repeatable between the two crosses, whereas others were specific to only one cross. These results suggest that variation in the number of papillary processes is polygenic and controlled by QTL that are distinct from those controlling anal fin length. Thus, different courtship traits in Japanese medaka share a small number of QTL and have the potential for independent evolution. Copyright © 2015 Kawajiri et al.

Evolution and Expression of Tissue Globins in Ray-Finned Fishes.

PubMed

Gallagher, Michael D; Macqueen, Daniel J

2017-01-01

The globin gene family encodes oxygen-binding hemeproteins conserved across the major branches of multicellular life. The origins and evolutionary histories of complete globin repertoires have been established for many vertebrates, but there remain major knowledge gaps for ray-finned fish. Therefore, we used phylogenetic, comparative genomic and gene expression analyses to discover and characterize canonical “non-blood” globin family members (i.e., myoglobin, cytoglobin, neuroglobin, globin-X, and globin-Y) across multiple ray-finned fish lineages, revealing novel gene duplicates (paralogs) conserved from whole genome duplication (WGD) and small-scale duplication events. Our key findings were that: (1) globin-X paralogs in teleosts have been retained from the teleost-specific WGD, (2) functional paralogs of cytoglobin, neuroglobin, and globin-X, but not myoglobin, have been conserved from the salmonid-specific WGD, (3) triplicate lineage-specific myoglobin paralogs are conserved in arowanas (Osteoglossiformes), which arose by tandem duplication and diverged under positive selection, (4) globin-Y is retained in multiple early branching fish lineages that diverged before teleosts, and (5) marked variation in tissue-specific expression of globin gene repertoires exists across ray-finned fish evolution, including several previously uncharacterized sites of expression. In this respect, our data provide an interesting link between myoglobin expression and the evolution of air breathing in teleosts. Together, our findings demonstrate great-unrecognized diversity in the repertoire and expression of nonblood globins that has arisen during ray-finned fish evolution.

Evolution and Expression of Tissue Globins in Ray-Finned Fishes

PubMed Central

Gallagher, Michael D.

2017-01-01

The globin gene family encodes oxygen-binding hemeproteins conserved across the major branches of multicellular life. The origins and evolutionary histories of complete globin repertoires have been established for many vertebrates, but there remain major knowledge gaps for ray-finned fish. Therefore, we used phylogenetic, comparative genomic and gene expression analyses to discover and characterize canonical “non-blood” globin family members (i.e., myoglobin, cytoglobin, neuroglobin, globin-X, and globin-Y) across multiple ray-finned fish lineages, revealing novel gene duplicates (paralogs) conserved from whole genome duplication (WGD) and small-scale duplication events. Our key findings were that: (1) globin-X paralogs in teleosts have been retained from the teleost-specific WGD, (2) functional paralogs of cytoglobin, neuroglobin, and globin-X, but not myoglobin, have been conserved from the salmonid-specific WGD, (3) triplicate lineage-specific myoglobin paralogs are conserved in arowanas (Osteoglossiformes), which arose by tandem duplication and diverged under positive selection, (4) globin-Y is retained in multiple early branching fish lineages that diverged before teleosts, and (5) marked variation in tissue-specific expression of globin gene repertoires exists across ray-finned fish evolution, including several previously uncharacterized sites of expression. In this respect, our data provide an interesting link between myoglobin expression and the evolution of air breathing in teleosts. Together, our findings demonstrate great-unrecognized diversity in the repertoire and expression of nonblood globins that has arisen during ray-finned fish evolution. PMID:28173090

Fins improve the swimming performance of fish sperm: a hydrodynamic analysis of the Siberian sturgeon Acipenser baerii.

PubMed

Gillies, Eric A; Bondarenko, Volodymyr; Cosson, Jacky; Pacey, Allan A

2013-02-01

The flagella of sturgeon sperm have an ultrastructure comprising paddle-like fins extending along most of their length. These fins are seen in several other marine and freshwater fish. The sperm of these fish are fast swimmers and are relatively short lived: it is therefore tempting to think of these fins as having evolved for hydrodynamic advantage, but the actual advantage they impart, at such a small length scale and slow speed, is unclear. The phrase "the fins improve hydrodynamic efficiency" is commonly found in biological literature, yet little hydrodynamic analysis has previously been used to support such conjectures. In this paper, we examine various hydrodynamic models of sturgeon sperm and investigate both swimming velocity and energy expenditure. All of the models indicate a modest hydrodynamic advantage of finned sperm, in both straight line swimming speed and a hydrodynamic efficiency measure. We find a hydrodynamic advantage for a flagellum with fins, over one without fins, of the order of 15-20% in straight line propulsive velocity and 10-15% in a hydrodynamic efficiency measure. Copyright © 2012 Wiley Periodicals, Inc.

Administration of SIN-1 induces guinea pig airway hyperresponsiveness through inactivation of airway neutral endopeptidase.

PubMed

Kanazawa, H; Hirata, K; Yoshikawa, J

1999-12-01

Peroxynitrite plays an important role in the pathogenesis of airway inflammation. We have already found that peroxynitrite may contribute to decreased beta(2)-adrenoceptor responses in airway smooth muscle. However, it is not known whether peroxynitrite can alter neutral endopeptidase (EC 3.4.24.11; NEP) activity in the airways. This study was designed to determine whether peroxynitrite induces airway hyperresponsiveness to substance P (SP) and endothelin-1 (ET-1) through the inactivation of airway NEP. We examined whether the administration of S-morpholinosydnonimine (SIN-1), a compound that releases peroxynitrite, increased bronchoconstrictor responses to SP and ET-1 in anesthetized guinea pigs. In addition, we assayed NEP activity in the airways of SIN-1-exposed guinea pigs. Though SIN-1 (10(-7) M) alone had no effect on pulmonary resistance, pretreatment with SIN-1 significantly enhanced SP- and ET-1-induced bronchoconstriction. Pretreatment with phosphoramidon, an NEP inhibitor, also enhanced SP- and ET-1-induced bronchoconstriction. However, simultaneous administration of phosphoramidon and SIN-1 had no additive effect on SP- and ET-1-induced bronchoconstriction. Peroxynitrite formation by SIN-1 was completely inhibited by N-acetylcysteine (NAC) and glutathione (GSH) in vitro, and pretreatment with NAC and GSH significantly reversed the potentiation by SIN-1 of SP-induced bronchoconstriction. In addition, the NEP activity of the trachea after SIN-1 exposure was significantly reduced compared to the level in control guinea pigs (solvent for SIN-1: 30.0+/-4.2 fmol.min(-1).mg tissue(-1); 10(-7) M SIN-1; 15.5+/-4.5 fmol.min(-1).mg tissue(-1), p<0.05). These findings suggest that peroxynitrite induces airway hyperresponsiveness to SP and ET-1 through the inactivation of airway NEP, and that peroxynitrite is an important mediator of the alterations in airway functions.

Study on finned pipe performance as a ground heat exchanger

NASA Astrophysics Data System (ADS)

Lin, Qinglong; Ma, Jinghui; Shi, Lei

2017-08-01

The GHEs (ground heat exchangers) is an important element that determines the thermal efficiency of the entire ground-source heat-pump system. The aim of the present study is to clarify thermal performance of a new type GHE pipe, which consists straight fins of uniform cross sectional area. In this paper, GHE model is introduced and an analytical model of new type GHE pipe is developed. The heat exchange rate of BHEs utilizing finned pips is 40.42 W/m, which is 16.3% higher than normal BHEs, based on simulation analyses.

Evolution of caudal fin ray development and caudal fin hypural diastema complex in spotted gar, teleosts, and other neopterygian fishes.

PubMed

Desvignes, Thomas; Carey, Andrew; Postlethwait, John H

2018-06-01

The caudal fin of actinopterygians transitioned from a heterocercal dorsoventrally asymmetrical fin to a homocercal externally symmetrical fin in teleosts through poorly understood evolutionary developmental mechanisms. We studied the caudal skeleton of major living actinopterygian lineages, including polypteriformes, acipenseriformes, Holostei (gars and bowfin), and teleosts, compared with reports of extinct neopterygians and basal teleosteans. We focused on the hypural diastema complex, which includes (1) a gap between hypurals 2 and 3, that (2) separates two plates of connective tissue at (3) the branching of caudal vasculature; these features had been considered as a shared, derived trait of teleosts, a synapomorphy. These studies revealed that gars and teleosts share all three features of the hypural diastema complex. Absence of a complex with these features from bowfin, fossil Holostei, and stem Teleostei argues in favor of repetitive, independent emergence in several neopterygian and basal Teleostei lineages, or less likely, many independent losses. We further observed that, in gars and teleosts, the earliest developing lepidotrichia align with the horizontal adult body axis, thus participating in external symmetry. These results suggest that the hypural diastema complex in teleosts and gars represents a homoplasy among neopterygians and that it emerged repeatedly by parallel evolution due to shared inherited underlying genetic and developmental programs (latent homology). Because the hypural diastema complex exists in gars with heterocercal tails, this complex is independent of homocercality. Developmental Dynamics 247:832-853, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

The Prx1 limb enhancers: targeted gene expression in developing zebrafish pectoral fins.

PubMed

Hernández-Vega, Amayra; Minguillón, Carolina

2011-08-01

Limbs represent an excellent model to study the induction, growth, and patterning of several organs. A breakthrough to study gene function in various tissues has been the characterization of regulatory elements that allow tissue-specific interference of gene function. The mouse Prx1 promoter has been used to generate limb-specific mutants and overexpress genes in tetrapod limbs. Although zebrafish possess advantages that favor their use to study limb morphogenesis, there is no driver described suitable for specifically interfering with gene function in developing fins. We report the generation of zebrafish lines that express enhanced green fluorescent protein (EGFP) driven by the mouse Prx1 enhancer in developing pectoral fins. We also describe the expression pattern of the zebrafish prrx1 genes and identify three conserved non-coding elements (CNEs) that we use to generate fin-specific EGFP reporter lines. Finally, we show that the mouse and zebrafish regulatory elements may be used to modify gene function in pectoral fins. Copyright © 2011 Wiley-Liss, Inc.

Temporal separation of two fin whale call types across the eastern North Pacific.

PubMed

Sirović, Ana; Williams, Lauren N; Kerosky, Sara M; Wiggins, Sean M; Hildebrand, John A

2013-01-01

Fin whales ( Balaenoptera physalus ) produce a variety of low-frequency, short-duration, frequency-modulated calls. The differences in temporal patterns between two fin whale call types are described from long-term passive acoustic data collected intermittently between 2005 and 2011 at three locations across the eastern North Pacific: the Bering Sea, off Southern California, and in Canal de Ballenas in the northern Gulf of California. Fin whale calls were detected at all sites year-round, during all periods with recordings. At all three locations, 40-Hz calls peaked in June, preceding a peak in 20-Hz calls by 3-5 months. Monitoring both call types may provide a more accurate insight into the seasonal presence of fin whales across the eastern North Pacific than can be obtained from a single call type. The 40-Hz call may be associated with a foraging function, and temporal separation between 40- and 20-Hz calls may indicate the separation between predominately feeding behavior and other social interactions.

An experimental study of three-dimensional shock wave/boundary layer interactions generated by sharp fins

NASA Technical Reports Server (NTRS)

Lu, F. K.; Settles, G. S.; Bogdonoff, S. M.

1983-01-01

The interaction between a turbulent boundary layer and a shock wave generated by a sharp fin with leading edge sweepback was investigated. The incoming flow was at Mach 2.96 and at a unit Reynolds number of 63 x 10 to the 6th power 0.1 m. The approximate incoming boundary layer thickness was either 4 mm or 17 mm. The fins used were at 5 deg, 9 deg and 15 deg incidence and had leading edge sweepback from 0 deg to 65 deg. The tests consisted of surface kerosene lampblack streak visualization, surface pressure measurements, shock wave shape determination by shadowgraphs, and localized vapor screen visualization. The upstream influence lengths of the fin interactions were correlated using viscous and inviscid flow parameters. The parameters affecting the surface features close to the fin and way from the fin were also identified. Essentially, the surface features in the farfield were found to be conical.

Modeling, Fabrication, and Analysis of Vertical Conduction Gallium Nitride Fin MOSFET

NASA Astrophysics Data System (ADS)

Tahhan, Maher Bishara

Gallium Nitride has seen much interest in the field of electronics due to its large bandgap and high mobility. In the field of power electronics, this combination leads to a low on-resistance for a given breakdown voltage. To take full advantage of this, vertical conduction transistors in GaN can give high breakdown voltages independent of chip area, leading to transistors with nominally low on resistance with high breakdown at a low cost. Acknowledging this, a vertical transistor design is presented with a small footprint area. This design utilizes a fin structure as a double gated insulated MESFET with electrons flowing from the top of the fin downward. The transistor's characteristics and design is initially explored via simulation and modelling. In this modelling, it is found that the narrow dimension of the fin must be sub-micron to allow for the device to be turned off with no leakage current and have a positive threshold voltage. Several process modules are developed and integrated to fabricate the device. A smooth vertical etch leaving low damage to the surfaces is demonstrated and characterized, preventing micromasking during the GaN dry etch. Methods of removing damage from the dry etch are tested, including regrowth and wet etching. Several hard masks were developed to be used in conjunction with this GaN etch for various requirements of the process, such as material constraints and self-aligning a metal contact. Multiple techniques are tested to deposit and pattern the gate oxide and metal to ensure good contact with the channel without causing unwanted shorts. To achieve small fin dimensions, a self-aligned transistor process flow is presented allowing for smaller critical dimensions at increased fabrication tolerances by avoiding the use of lithographic steps that require alignments to very high accuracy. In the case of the device design presented, the fins are lithographically defined at the limit of i-line stepper system. From this single

Electrochemical behavior of tube-fin assembly for an aluminum automotive condenser with improved corrosion resistance

NASA Astrophysics Data System (ADS)

Pech-Canul, M. A.; Guía-Tello, J. C.; Pech-Canul, M. I.; Aguilar, J. C.; Gorocica-Díaz, J. A.; Arana-Guillén, R.; Puch-Bleis, J.

An aluminum automotive condenser was designed to exhibit high corrosion resistance in the seawater acetic acid test (SWAAT) combining zinc coated microchannel tubes and fins made with AA4343/AA3003(Zn)/AA4343 brazing sheet. Electrochemical measurements in SWAAT solution were carried out under laboratory conditions using tube-fin assembly and individual fin and tube samples withdrawn from the condenser core. The aim was to gain information on the protective role of the zinc sacrificial layer and about changes in corrosion behavior as a function of immersion time. External corrosion of the tube-fin system was simulated by immersion of mini-core samples under open circuit conditions. The corrosion rate increased rapidly during the first 6 h and slowly afterwards. The short time behavior was related to the dissolution of the oxide film and fast dissolution of the outermost part of the zinc diffusion layer. With the aid of cross-sectional depth corrosion potential profiles, it was shown that as the sacrificial layer gets dissolved, the surface concentration of zinc decreases and the potential shifts to less negative values. The results of galvanic coupling of tube and fins in a mini-cell showed that the tube became the anode while the fins exhibited cathodic behavior. An evolution in the galvanic interaction was observed, due to the progressive dissolution of the sacrificial zinc layer. The difference of uncoupled potentials between tube and fins decreased from 71 mV to 32 mV after 84 h of galvanic coupling. At the end of such period there was still a part of the zinc sacrificial layer remaining which would serve for protection of the tube material for even longer periods and there were indications of slight corrosion in the fins.

Sexual Dimorphism and Geographic Variation in Dorsal Fin Features of Australian Humpback Dolphins, Sousa sahulensis.

PubMed

Brown, Alexander M; Bejder, Lars; Parra, Guido J; Cagnazzi, Daniele; Hunt, Tim; Smith, Jennifer L; Allen, Simon J

2016-01-01

Determining the sex of free-ranging cetaceans can be challenging. Sexual dimorphism among external features may allow inferences on sex, but such patterns may be difficult to detect and are often confounded by age and geographic variation. Dorsal fin images of 107 female and 54 male Australian humpback dolphins, Sousa sahulensis, from Western Australia (WA) and Queensland (QLD) were used to investigate sex, age and geographic differences in colouration, height/length quotient and number of notches. Adult males exhibited more dorsal fin notches (p<0.001) and a significantly greater loss of pigmentation on the upper half of their dorsal fins (p<0.001) than did adult females. These differences likely reflect that males experience a higher frequency and/or intensity of intraspecific aggression than females. In QLD, heavily spotted dorsal fins were more frequent among females than males (p<0.001). Logistic regression analyses revealed that dorsal fin spotting and loss of pigmentation on the upper half of the dorsal fin provided the best model parameters for predicting the sex of sampled adults, with 97% accuracy. This technique offers a rapid, non-invasive method for predicting sex in Australian humpback dolphins, which could potentially be applied to populations throughout their range. In contrast to adults, presumed immature animals showed little or no loss of pigmentation or spotting; however, the rate of development of these features remains unknown. There were pronounced differences between QLD and WA in the intensity of spotting on dorsal fins and the extent of pigmentation loss around the posterior insertion and trailing edge of the dorsal fin. While based on a limited sample size, these geographic differences may have conservation implications in terms of population subdivision and should be investigated further. © 2016 Elsevier Ltd. All rights reserved.

People Who Have Committed a Certain Sin Ought to Be Dead

ERIC Educational Resources Information Center

Leenaars, Antoon A.

2006-01-01

People who have committed a certain sin ought to be dead; I am a person who has committed that sin; therefore, I ought to be dead. Thus is the logic of a suicidal mind. Lester, Szaz, and others argue the "sinner" should always be allowed to kill him/herself. Shneidman, Leenaars and others do not agree. Once one knows the suicidal mind, it is easy…

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

PubMed Central

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

Heat transfer coefficients for staggered arrays of short pin fins

NASA Technical Reports Server (NTRS)

Vanfossen, G. J.

1981-01-01

Short pin fins are often used to increase that heat transfer to the coolant in the trailing edge of a turbine blade. Due primarily to limits of casting technology, it is not possible to manufacture pins of optimum length for heat transfer purposes in the trailing edge region. In many cases the pins are so short that they actually decrease the total heat transfer surface area compared to a plain wall. A heat transfer data base for these short pins is not available in the literature. Heat transfer coefficients on pin and endwall surfaces were measured for several staggered arrays of short pin fins. The measured Nusselt numbers when plotted versus Reynolds numbers were found to fall on a single curve for all surfaces tested. The heat transfer coefficients for the short pin fins (length to diameter ratios of 1/2 and 2) were found to be about a factor of two lower than data from the literature for longer pin arrays (length to diameter ratios of about 8).

Control Law Synthesis for Vertical Fin Buffeting Alleviation Using Strain Actuation

NASA Technical Reports Server (NTRS)

Nitzsche, F.; Zimcik, D. G.; Ryall, T. G.; Moses, R. W.; Henderson, D. A.

1999-01-01

In the present investigation, the results obtained during the ground test of a closed-loop control system conducted on a full-scale fighter to attenuate vertical fin buffeting response using strain actuation are presented. Two groups of actuators consisting of piezoelectric elements distributed over the structure were designed to achieve authority over the first and second modes of the vertical fin. The control laws were synthesized using the Linear Quadratic Gaussian (LQG) method for a time-invariant control system. Three different pairs of sensors including strain gauges and accelerometers at different locations were used to close the feedback loop. The results demonstrated that measurable reductions in the root-mean-square (RMS) values of the fin dynamic response identified by the strain transducer at the critical point for fatigue at the root were achieved under the most severe buffet condition. For less severe buffet conditions, reductions of up to 58% were achieved.

Total Ionizing Dose Effects on Strained Ge pMOS FinFETs on Bulk Si

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, En Xia; Fleetwood, Daniel M.; Hachtel, Jordan A.

2016-12-02

In this paper, we have characterized the total ionizing dose response of strained Ge p MOS FinFETs built on bulk Si using a fin replacement process. Devices irradiated to 1.0 Mrad(SiO 2) show minimal transconductance degradation (less than 5%), very small V th shifts (less than 40 mV in magnitude) and very little ON/OFF current ratio degradation (<5%), and only modest variation in radiation response with transistor geometry (typically less than normal part-to-part variation). Both before and after irradiation, the performance of these strained Ge p MOS FinFETs is far superior to that of past generations of planar Ge pmore » MOS devices. Finally, these improved properties result from significant improvements in processing technology, as well as the enhanced gate control provided by the strained Ge FinFET technology.« less

A global review of species-specific shark-fin-to-body-mass ratios and relevant legislation.

PubMed

Biery, L; Pauly, D

2012-04-01

In this review, shark-fin-to-body-mass ratios, which have been legislated by several countries as a means of regulating and monitoring shark fisheries, have been compiled and reviewed. Observed and legislated wet-fin-mass-to-round-mass (M(fw) :M(r) ) ratios have been collected for 50 species and eight countries. Wet to dry-fin mass conversion factors have also been reviewed. Existing shark fishery legislation was compiled by political entity and regional fishery management organizations (RFMO). The mean observed M(fw) :M(r) ratio for all species was 3·0%, but actual fin to body-mass ratios varied considerably by species and location. Species-specific mean ratios ranged from 1·1 to 10·9%, and estimated mean ratios ranged from 1·5 to 6·1% by country, depending on fin-cutting practices and the mix of exploited species. The mean conversion factor for wet to dry-fin mass was 0·43. Shark-related legislation was found to exist in 37 countries and the 22 maritime members of the European Union, and shark-related regulations have been designated by nine RFMOs. Results suggest that currently regulated ratios may not be appropriate for all species and fin-cutting practices, and regulations based on generalized ratios for all sharks may be inadequate. Alternative policies may be necessary for the effective management of global shark fisheries. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Heat-transfer coefficients for air flowing in round tubes, in rectangular ducts, and around finned cylinders

NASA Technical Reports Server (NTRS)

Drexel, Rober E; Mcadams, William H

1945-01-01

Report reviews published data and presents some new data on heat transfer to air flowing in round tubes, in rectangular ducts, and around finned cylinders. The available data for heat transfer to air in straight ducts of rectangular and circular cross section have been correlated in plots of Stanton number versus Reynolds number to provide a background for the study of the data for finned cylinders. Equations are recommended for both the streamlined and turbulent regions, and data are presented for the transition region between turbulent and laminar flow. Use of hexagonal ends on round tubes causes the characteristics of laminar flow to extend to high Reynolds numbers. Average coefficients for the entire finned cylinder have been calculated from the average temperature at the base of the fins and an equation which was derived to allow for the effectiveness of the fins. The available results for each finned cylinder are correlated herein in terms of graphs of Stanton number versus Reynolds number. In general, for a given Reynolds number, the Stanton number increases with increases in both spacing and width of the fins, and is apparently independent of cylinder diameter and temperature difference. For a given coefficient of heat transfer improved baffles and rough or wavy surfaces give a substantial reduction in pumping power per unit of heat transfer surface and a somewhat smaller decrease in pressure drop. (author)

Synchronous Seasonal Change in Fin Whale Song in the North Pacific

PubMed Central

Oleson, Erin M.; Širović, Ana; Bayless, Alexandra R.; Hildebrand, John A.

2014-01-01

Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here. PMID:25521493

Synchronous seasonal change in fin whale song in the North Pacific.

PubMed

Oleson, Erin M; Širović, Ana; Bayless, Alexandra R; Hildebrand, John A

2014-01-01

Fin whale (Balaenoptera physalus) song consists of down-swept pulses arranged into stereotypic sequences that can be characterized according to the interval between successive pulses. As in blue (B. musculus) and humpback whales (Megaptera novaeangliae), these song sequences may be geographically distinct and may correlate with population boundaries in some regions. We measured inter-pulse intervals of fin whale songs within year-round acoustic datasets collected between 2000 and 2006 in three regions of the eastern North Pacific: Southern California, the Bering Sea, and Hawaii. A distinctive song type that was recorded in all three regions is characterized by singlet and doublet inter-pulse intervals that increase seasonally, then annually reset to the same shorter intervals at the beginning of each season. This song type was recorded in the Bering Sea and off Southern California from September through May and off Hawaii from December through April, with the song interval generally synchronized across all monitoring locations. The broad geographic and seasonal occurrence of this particular fin whale song type may represent a single population broadly distributed throughout the eastern Pacific with no clear seasonal migratory pattern. Previous studies attempting to infer population structure of fin whales in the North Pacific using synchronous individual song samples have been unsuccessful, likely because they did not account for the seasonal lengthening in song intervals observed here.

Integrated Positioning for Coal Mining Machinery in Enclosed Underground Mine Based on SINS/WSN

PubMed Central

Hui, Jing; Wu, Lei; Yan, Wenxu; Zhou, Lijuan

2014-01-01

To realize dynamic positioning of the shearer, a new method based on SINS/WSN is studied in this paper. Firstly, the shearer movement model is built and running regularity of the shearer in coal mining face has been mastered. Secondly, as external calibration of SINS using GPS is infeasible in enclosed underground mine, WSN positioning strategy is proposed to eliminate accumulative error produced by SINS; then the corresponding coupling model is established. Finally, positioning performance is analyzed by simulation and experiment. Results show that attitude angle and position of the shearer can be real-timely tracked by integrated positioning strategy based on SINS/WSN, and positioning precision meet the demand of actual working condition. PMID:24574891

Fish fins as non-lethal surrogates for muscle tissues in freshwater food web studies using stable isotopes.

PubMed

Hette Tronquart, Nicolas; Mazeas, Laurent; Reuilly-Manenti, Liana; Zahm, Amandine; Belliard, Jérôme

2012-07-30

Dorsal white muscle is the standard tissue analysed in fish trophic studies using stable isotope analyses. However, sampling white muscle often implies the sacrifice of fish. Thus, we examined whether the non-lethal sampling of fin tissue can substitute muscle sampling in food web studies. Analysing muscle and fin δ(15)N and δ(13)C values of 466 European freshwater fish (14 species) with an elemental analyser coupled with an isotope ratio mass spectrometer, we compared the isotope values of the two tissues. Correlations between fin and muscle isotope ratios were examined for all fish together and specifically for 12 species. We further proposed four methods of assessing muscle from fin isotope ratios and estimated the errors made using these muscle surrogates. Despite significant differences between isotope values of the two tissues, fin and muscle isotopic signals are strongly correlated. Muscle values, estimated with raw fin isotope ratios (1st method), induce an error of ca. 1‰ for both isotopes. In comparison, specific (2nd method) or general (3rd method) correlations provide meaningful corrections of fin isotope ratios (errors <0.6‰). On the other hand, relationships, established for Australian tropical fish, only give poor muscle estimates (errors >0.8‰). There is little chance that a global model can be created. However, the 2nd and 3rd methods of estimating muscle values from fin isotope ratios should provide an acceptable level of error for the studies of European freshwater food web. We thus recommend that future studies use fin tissue as a non-lethal surrogate for muscle. Copyright © 2012 John Wiley & Sons, Ltd.

A light-colored region of caudal fin: a niche of melanocyte progenitors in crucian carp (Cyprinus carpio L.).

PubMed

Huang, Yaping; Luo, Yurong; Liu, Jinhui; Gui, Saiyu; Wang, Mei; Liu, Wenbin; Peng, Liangyue; Xiao, Yamei

2017-01-01

Melanocyte stem cells are a population of immature cells which sustain the self-renewal and replenish the differentiated melanocytes. In this research, a light-colored region (LCR) is observed at the heel of caudal fin in juvenile crucian carp. By cutting off the caudal fin, the operated caudal fin can regenerate in accordance with the original pigment pattern from the retained LCR. As markers of stem cells, Oct4 and Sox2 have been found to be highly expressed in the LCR as well as Mitfa, a label of the melanoblasts. In vitro, Mitfa + melanoblasts are observed in the cells which are derived from the LCR and transfected with Mitfa-EGFP reporter by using Tol2 transposon system. Furthermore, by real-time qPCR, it is shown that the level of sox2 mRNA is gradually decreased from the LCR to proximal and distal caudal fin, and that of mitfa mRNA in the proximal caudal fin (PCF) is higher than that in the LCR, while it is the lowest in the distal caudal fin. Hence, we propose that the LCR is a pigment progenitor niche, sending melanocytes to the distal of caudal fin, which gradually emerges as caudal fin grow. We reveal that the LCR of caudal fin might be a niche of pigment progenitors, and contribute to pigment-producing stem cells in crucian carp. © 2016 International Federation for Cell Biology.

Experimental Study of Heat Transfer Enhancements from Array of Alternate Rectangular Dwarf Fins at Different Inclinations

NASA Astrophysics Data System (ADS)

Awasarmol, Umesh Vandeorao; Pise, Ashok T.

2018-02-01

The main objective of this experimental work is to investigate and compare heat transfer enhancement of alternate dwarf fin array at different angles of inclination. In this study, the steady state heat transfer from the full length fin arrays and alternate dwarf fin arrays are measured in natural convection and radiation environment. Largest increase in the Nusselt number was achieved with alternate dwarf fin at angle of orientation 90°, which shows about 28% enhanced heat transfer coefficient as opposed to the full-length fin array with 25% saving in material. In case of non-black FAB, contribution of radiation heat transfer is found to be very small nearly within 1% of the heater input. After coating lamp black contribution of radiation heat transfer is found to increase to about 3-4% of the heater input in the range of temperatures considered in this study.

Numerical study of the thermo-flow performances of novel finned tubes for air-cooled condensers in power plant

NASA Astrophysics Data System (ADS)

Guo, Yonghong; Du, Xiaoze; Yang, Lijun

2018-02-01

Air-cooled condenser is the main equipment of the direct dry cooling system in a power plant, which rejects heat of the exhaust steam with the finned tube bundles. Therefore, the thermo-flow performances of the finned tubes have an important effect on the optimal operation of the direct dry cooling system. In this paper, the flow and heat transfer characteristics of the single row finned tubes with the conventional flat fins and novel jagged fins are investigated by numerical method. The flow and temperature fields of cooling air for the finned tubes are obtained. Moreover, the variations of the flow resistance and average convection heat transfer coefficient under different frontal velocity of air and jag number are presented. Finally, the correlating equations of the friction factor and Nusselt number versus the Reynolds number are fitted. The results show that with increasing the frontal velocity of air, the heat transfer performances of the finned tubes are enhanced but the pressure drop will increase accordingly, resulting in the average convection heat transfer coefficient and friction factor increasing. Meanwhile, with increasing the number of fin jag, the heat transfer performance is intensified. The present studies provide a reference in optimal designing for the air-cooled condenser of direct air cooling system.

Unusual anal fin in a Devonian jawless vertebrate reveals complex origins of paired appendages

PubMed Central

Sansom, Robert S.; Gabbott, Sarah E.; Purnell, M. A.

2013-01-01

Jawed vertebrates (gnathostomes) have undergone radical anatomical and developmental changes in comparison with their jawless cousins (cyclostomes). Key among these is paired appendages (fins, legs and wings), which first evolved at some point on the gnathostome stem. The anatomy of fossil stem gnathostomes is, therefore, fundamental to our understanding of the nature and timing of the origin of this complex innovation. Here, we show that Euphanerops, a fossil jawless fish from the Devonian, possessed paired anal-fin radials, but no pectoral or pelvic fins. This unique condition occurs at an early stage on the stem-gnathostome lineage. This condition, and comparison with the varied condition of paired fins in other ostracoderms, indicates that there was a large amount of developmental plasticity during this episode—rather than a gradual evolution of this complex feature. Apparently, a number of different clades were exploring morphospace or undergoing multiple losses. PMID:23576777

Destroying God's Temple? Physical Inactivity, Poor Diet, Obesity, and Other "Sin" Behaviors.

PubMed

Faries, Mark D; McClendon, Megan; Jones, Eric J

2017-02-17

On average, our participants (N = 112), who self-proclaimed to be Christians, believed that physically inactive lifestyles, unhealthy eating, overeating, and being obese destroy the body, God's temple. However, these beliefs were less definitive, than those of other common "sin" behaviors, such as drug use, smoking, and excessive drinking of alcohol. In addition, destroying the body with physical inactivity or poor diet was not necessarily viewed as sinful. Subsequently, these beliefs did not relate to self-reported physical activity, dietary behavior, or body mass index. It is possible that inactivity, poor dietary habits, and obesity are not internalized into the spiritual perspective as destroying the body, God's temple, in the same way as other "sin" behaviors.

[[Abortion: An Unforgivable Sin?].

PubMed

Lalli, Chiara

Abortion has become something to hide, something you can't tell other people, something you have to expiate forever. Besides, abortion is more and more difficult to achieve because of the raising average of consciencious objection (from 70 to 90% of health care providers are conscientious objectors, 2014 data, Ministero della Salute) and illegal abortion is "coming back"from the 70s, when abortion was a crime (Italian law n. 194/1978). Abortion is often blamed as a murder, an unforgivenable sin, even as genocide. Silence against shouting "killers!" to women who are going to have an abortion: this is a common actual scenario. Why is it so difficult to discuss and even to mention abortion?

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

PubMed

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).

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

PubMed

Naik, Mugdha S; Singh, Sahjendra N; Mittal, Rajat

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.

Static Longitudinal Stability of a Rocket Vehicle Having a Rear-Facing Step Ahead of the Stabilizing Fins

NASA Technical Reports Server (NTRS)

Keynton, Robert J.

1961-01-01

Tests were conducted at Mach numbers of 3.96 and 4.65 in the Langley Unitary Plan wind tunnel to determine the static longitudinal stability characteristics of a fin-stabilized rocket-vehicle configuration which had a rearward facing step located upstream of the fins. Two fin sizes and planforms, a delta and a clipped delta, were tested. The angle of attack was varied from 6 deg to -6 deg and the Reynolds number based on model 6 length was about 10 x 10. The configuration with the larger fins (clipped delta) had a center of pressure slightly rearward of and an initial normal-force-curve slope slightly higher than that of the configuration with the smaller fins (delta) as would be expected. Calculations of the stability parameters gave a slightly lower initial slope of the normal-force curve than measured data, probably because of boundary-layer separation ahead of the step. The calculated center of pressure agreed well with the measured data. Measured and calculated increments in the initial slope of the normal-force curve and in the center of pressure, due to changing fins, were in excellent agreement indicating that separated flow downstream of the step did not influence flow over the fins. This result was consistent with data from schlieren photographs.

Temperature dependency of double material gate oxide (DMGO) symmetric dual-k spacer (SDS) wavy FinFET

NASA Astrophysics Data System (ADS)

Pradhan, K. P.; Priyanka; Sahu, P. K.

2016-01-01

Symmetric Dual-k Spacer (SDS) Trigate Wavy FinFET is a novel hybrid device that combines three significant and advanced technologies i.e., ultra-thin-body (UTB), FinFET, and symmetric spacer engineering on a single silicon on insulator (SOI) platform. This innovative architecture promises to enhance the device performance as compared to conventional FinFET without increasing the chip area. For the first time, we have incorporated two different dielectric materials (SiO2, and HfO2) as gate oxide to analyze the effect on various performance metrics of SDS wavy FinFET. This work evaluates the response of double material gate oxide (DMGO) on parameters like mobility, on current (Ion), transconductance (gm), transconductance generation factor (TGF), total gate capacitance (Cgg), and cutoff frequency (fT) in SDS wavy FinFET. This work also reveals the presence of biasing point i.e., zero temperature coefficient (ZTC) bias point. The ZTC bias point is that point where the device parameters become independent of temperature. The impact of operating temperature (T) on above said various performances are also subjected to extensive analysis. This further validates the reliability of DMGO-SDS FinFET and its application opportunities involved in modeling analog/RF circuits for a broad range of temperature applications. From extensive 3-D device simulation, we have determined that the inclusion of DMGO in SDS wavy FinFET is superior in performance.

Structure and mechanical implications of the pectoral fin skeleton in the Longnose Skate (Chondrichthyes, Batoidea).

PubMed

Huang, Wei; Hongjamrassilp, Watcharapong; Jung, Jae-Young; Hastings, Philip A; Lubarda, Vlado A; McKittrick, Joanna

2017-03-15

Animal propulsion systems are believed to show high energy and mechanical efficiency in assisting movement compared to artificial designs. As an example, batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming via enlarged wing-like pectoral fins. The aim of this work is to illustrate the hierarchical structure of the pectoral fin of a representative batoid, the Longnose Skate (Raja rhina), and explain the mechanical implications of its structural design. At the macro level, the pectoral fins are comprised of radially oriented fin rays, formed by staggered mineralized skeletal elements stacked end-to-end. At the micro level, the midsection of each radial element is composed of three mineralized components, which consist of discrete segments (tesserae) that are mineralized cartilage and embedded in unmineralized cartilage. The radial elements are wrapped with aligned, unmineralized collagen fibers. This is the first report of the detailed structure of the ray elements, including the observation of a 3-chain mineralized tesserae. Structural analyses demonstrate that this configuration enhances stiffness in multiple directions. A two-dimensional numerical model based on the morphological analysis demonstrated that the tessera structure helps distributing shear, tensile and compressive stress more ideally, which can better support both lift and thrust forces when swimming without losing flexibility. Batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming by applying their enlarged wing-like pectoral fins. Previous studies have shown structural features and mechanical properties of the mineralized cartilage skeleton in various batoid fishes. However, the details of the pectoral fin structure at different length scales, as well as the relationship between the mechanical properties and structural design remains unknown. The present work illustrates the hierarchical structure of the pectoral fin of

Cooling system having reduced mass pin fins for components in a gas turbine engine

DOEpatents

Lee, Ching-Pang; Jiang, Nan; Marra, John J

2014-03-11

A cooling system having one or more pin fins with reduced mass for a gas turbine engine is disclosed. The cooling system may include one or more first surfaces defining at least a portion of the cooling system. The pin fin may extend from the surface defining the cooling system and may have a noncircular cross-section taken generally parallel to the surface and at least part of an outer surface of the cross-section forms at least a quartercircle. A downstream side of the pin fin may have a cavity to reduce mass, thereby creating a more efficient turbine airfoil.

Sounds from airguns and fin whales recorded in the mid-Atlantic Ocean, 1999-2009.

PubMed

Nieukirk, Sharon L; Mellinger, David K; Moore, Sue E; Klinck, Karolin; Dziak, Robert P; Goslin, Jean

2012-02-01

Between 1999 and 2009, autonomous hydrophones were deployed to monitor seismic activity from 16° N to 50° N along the Mid-Atlantic Ridge. These data were examined for airgun sounds produced during offshore surveys for oil and gas deposits, as well as the 20 Hz pulse sounds from fin whales, which may be masked by airgun noise. An automatic detection algorithm was used to identify airgun sound patterns, and fin whale calling levels were summarized via long-term spectral analysis. Both airgun and fin whale sounds were recorded at all sites. Fin whale calling rates were higher at sites north of 32° N, increased during the late summer and fall months at all sites, and peaked during the winter months, a time when airgun noise was often prevalent. Seismic survey vessels were acoustically located off the coasts of three major areas: Newfoundland, northeast Brazil, and Senegal and Mauritania in West Africa. In some cases, airgun sounds were recorded almost 4000 km from the survey vessel in areas that are likely occupied by fin whales, and at some locations airgun sounds were recorded more than 80% days/month for more than 12 consecutive months. © 2012 Acoustical Society of America

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

NASA Astrophysics Data System (ADS)

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

Thermal performance of plate fin heat sink cooled by air slot impinging jet with different cross-sectional area

NASA Astrophysics Data System (ADS)

Mesalhy, O. M.; El-Sayed, Mostafa M.

2015-06-01

Flow and heat transfer characteristics of a plate-fin heat sink cooled by a rectangular impinging jet with different cross-sectional area were studied experimentally and numerically. The study concentrated on investigating the effect of jet width, fin numbers, and fin heights on thermal performance. Entropy generation minimization method was used to define the optimum design and operating conditions. It is found that, the jet width that minimizes entropy generation changes with heat sink height and fin numbers.

Fin whale song variability in southern California and the Gulf of California.

PubMed

Širović, Ana; Oleson, Erin M; Buccowich, Jasmine; Rice, Ally; Bayless, Alexandra R

2017-08-31

Songs are distinct, patterned sounds produced by a variety of animals including baleen whales. Fin whale songs, which consist of short pulses repeated at regular interpulse intervals (IPIs), have been suggested as a tool to distinguish populations. Fin whale songs were analyzed from data collected from 2000-2012 in Southern California and from 2004-2010 in the Gulf of California using autonomous acoustic recorders. IPIs were measured for each identifiable song sequence during two random days of each month with recordings. Four distinct song types were identified: long doublet, short doublet, long triplet, and short triplet. Long and short doublets were the dominant songs in Southern California, while long and short triplets were dominant in the Gulf of California. An abrupt change in song type occurred in both areas during the monitoring period. We argue that each song type is unique to a population and these changes represent a shift in the primary population in the monitoring area. Occasional temporal and spatial song overlap indicated some exchange or visitation among populations. Fin whales appear to synchronize and gradually modify song rhythm over long time scales. A better understanding of the evolutionary and ecological importance of songs to fin whale populations is needed.

Study on Fins' Effect of Boiling Flow in Millimeter Channel Heat Exchanger

NASA Astrophysics Data System (ADS)

Watanabe, Satoshi

2005-11-01

Recently, a lot of researches about compact heat exchangers with mini-channels have been carried out with the hope of obtaining a high-efficiency heat transfer, due to the higher ratio of surface area than existing heat exchangers. However, there are many uncertain phenomena in fields such as boiling flow in mini-channels. Thus, in order to understand the boiling flow in mini-channels to design high-efficiency heat exchangers, this work focused on the visualization measurement of boiling flow in a millimeter channel. A transparent acrylic channel (heat exchanger form), high-speed camera (2000 fps at 1024 x 1024 pixels), and halogen lamp (backup light) were used as the visualization system. The channel's depth is 2 mm, width is 30 mm, and length is 400 mm. In preparation for commercial use, two types of channels were experimented on: a fins type and a normal slit type (without fins). The fins are circular cylindrical obstacles (diameter is 5 mm) to promote heat transfer, set in a triangular array (distance between each center point is 10 mm). Especially in this work, boiling flow and heat transfer promotion in the millimeter channel heat exchanger with fins was evaluated using a high-speed camera.

KinFin: Software for Taxon-Aware Analysis of Clustered Protein Sequences.

PubMed

Laetsch, Dominik R; Blaxter, Mark L

2017-10-05

The field of comparative genomics is concerned with the study of similarities and differences between the information encoded in the genomes of organisms. A common approach is to define gene families by clustering protein sequences based on sequence similarity, and analyze protein cluster presence and absence in different species groups as a guide to biology. Due to the high dimensionality of these data, downstream analysis of protein clusters inferred from large numbers of species, or species with many genes, is nontrivial, and few solutions exist for transparent, reproducible, and customizable analyses. We present KinFin, a streamlined software solution capable of integrating data from common file formats and delivering aggregative annotation of protein clusters. KinFin delivers analyses based on systematic taxonomy of the species analyzed, or on user-defined, groupings of taxa, for example, sets based on attributes such as life history traits, organismal phenotypes, or competing phylogenetic hypotheses. Results are reported through graphical and detailed text output files. We illustrate the utility of the KinFin pipeline by addressing questions regarding the biology of filarial nematodes, which include parasites of veterinary and medical importance. We resolve the phylogenetic relationships between the species and explore functional annotation of proteins in clusters in key lineages and between custom taxon sets, identifying gene families of interest. KinFin can easily be integrated into existing comparative genomic workflows, and promotes transparent and reproducible analysis of clustered protein data. Copyright © 2017 Laetsch and Blaxter.

Impingement thermal performance of perforated circular pin-fin heat sinks

NASA Astrophysics Data System (ADS)

Wen, Mao-Yu; Yeh, Cheng-Hsiung

2018-04-01

The study presents the experimental information on heat transfer performance of jet impingement cooling on circular pin- fin heat sinks with/without a hollow perforated base plate. Smoke flow visualization is also used to investigate the behavior of the complicated flow phenomena of the present heat sinks for this impingement cooling. The effects of flow Reynolds numbers (3458≤Re≤11,526), fin height, the geometry of the heat sinks (with/without a hollow perforated base plate), and jet-to-test heat sink placement (1 ≤ H/ d≤16) are examined. In addition, empirical correlation to estimate the heat transfer coefficient was also developed.

Low-Power and High-Speed Technique for logic Gates in 20nm Double-Gate FinFET Technology

NASA Astrophysics Data System (ADS)

Priydarshi, A.; Chattopadhyay, M. K.

2016-10-01

The FinFET is the leading example of multigate MOSFETS to substitute conventional single gate MOSFETs for ultimate scaling [1], The FinFET structure is a combination of a thin channel region and a double gate to suppress the short channel effects (SCEs) and Vthvariation [2], By using FinFET,figure of merits viz, ION, IOFF, output resistance, propagation delay, noise margin and leakage power, can be improved for ultra low power and high performance applications[3]. In this paper, a new high speed low power dynamic circuit design technique has been proposed using 20nm FinFETs. By applying the appropriate clock and sleep signal to the back gates of the FinFETs, the proposed circuit can efficiently control the dynamic power, During the pre-charging period, Vth of PMOS is controlled low so that a fast precharging can occur;

Static aeroelastic analysis and tailoring of missile control fins

NASA Technical Reports Server (NTRS)

Mcintosh, S. C., Jr.; Dillenius, M. F. E.

1989-01-01

A concept for enhancing the design of control fins for supersonic tactical missiles is described. The concept makes use of aeroelastic tailoring to create fin designs (for given planforms) that limit the variations in hinge moments that can occur during maneuvers involving high load factors and high angles of attack. It combines supersonic nonlinear aerodynamic load calculations with finite-element structural modeling, static and dynamic structural analysis, and optimization. The problem definition is illustrated. The fin is at least partly made up of a composite material. The layup is fixed, and the orientations of the material principal axes are allowed to vary; these are the design variables. The objective is the magnitude of the difference between the chordwise location of the center of pressure and its desired location, calculated for a given flight condition. Three types of constraints can be imposed: upper bounds on static displacements for a given set of load conditions, lower bounds on specified natural frequencies, and upper bounds on the critical flutter damping parameter at a given set of flight speeds and altitudes. The idea is to seek designs that reduce variations in hinge moments that would otherwise occur. The block diagram describes the operation of the computer program that accomplishes these tasks. There is an option for a single analysis in addition to the optimization.

Relationships of mercury concentrations across tissue types, muscle regions and fins for two shark species.

PubMed

O'Bryhim, Jason R; Adams, Douglas H; Spaet, Julia L Y; Mills, Gary; Lance, Stacey L

2017-04-01

Mercury (Hg) exposure poses a threat to both fish and human health. Sharks are known to bioaccumulate Hg, however, little is known regarding how Hg is distributed between different tissue groups (e.g. muscle regions, organs). Here we evaluated total mercury (THg) concentrations from eight muscle regions, four fins (first dorsal, left and right pectorals, caudal-from both the inner core and trailing margin of each fin), and five internal organs (liver, kidney, spleen, heart, epigonal organ) from two different shark species, bonnethead (Sphyrna tiburo) and silky shark (Carcharhinus falciformis) to determine the relationships of THg concentrations between and within tissue groups. Total Hg concentrations were highest in the eight muscle regions with no significant differences in THg concentrations between the different muscle regions and muscle types (red and white). Results from tissue collected from any muscle region would be representative of all muscle sample locations. Total Hg concentrations were lowest in samples taken from the fin inner core of the first dorsal, pectoral, and caudal (lower lobe) fins. Mercury concentrations for samples taken from the trailing margin of the dorsal, pectoral, and caudal fins (upper and lower lobe) were also not significantly different from each other for both species. Significant relationships were found between THg concentrations in dorsal axial muscle tissue and the fin inner core, liver, kidney, spleen and heart for both species as well as the THg concentrations between the dorsal fin trailing margin and the heart for the silky shark and all other sampled tissue types for the bonnethead shark. Our results suggest that biopsy sampling of dorsal muscle can provide data that can effectively estimate THg concentrations in specific organs without using more invasive, or lethal methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effect of Fin Pitch on Fluid Elastic Instability of Tube Arrays Subjected to Cross Flow of Water

NASA Astrophysics Data System (ADS)

Desai, Sandeep Rangrao; Pavitran, Sampat

2018-02-01

Failure of tubes in shell and tube exchangers is attributed to flow induced vibrations of such tubes. There are different excitations mechanisms due to which flow induced vibration occurs and among such mechanisms, fluid elastic instability is the most prominent one as it causes the most violent vibrations and may lead to rapid tube failures within short time. Fluid elastic instability is the fluid-structure interaction phenomenon which occurs when energy input by the fluid force exceeds energy expended in damping. This point is referred as instability threshold and corresponding velocity is referred as critical velocity. Once flow velocity exceeds critical flow velocity, the vibration amplitude increases very rapidly with flow velocity. An experimental program is carried out to determine the critical velocity at instability for plain and finned tube arrays subjected to cross flow of water. The tube array geometry is parallel triangular with cantilever end condition and pitch ratios considered are 2.6 and 2.1. The objective of research is to determine the effect of increase in pitch ratio on instability threshold for plain tube arrays and to assess the effect of addition of fins as well as increase in fin density on instability threshold for finned tube arrays. Plain tube array with two different pitch ratios; 2.1 and 2.6 and finned tube arrays with same pitch ratio; 2.6 but with two different fin pitches; such as fine (10 fpi) and coarse (4 fpi) are considered for the experimentation. Connors' equation that relates critical velocity at instability to different parameters, on which instability depends, has been used as the basis for analysis and the concept of effective diameter is used for the present investigation. The modal parameters are first suitably modified using natural frequency reduction setup that is already designed and developed to reduce natural frequency and hence to achieve experimental simulation of fluid elastic instability within the limited

Original Sin and T. E. Hulme's Aesthetics

ERIC Educational Resources Information Center

Kishler, Thomas C.

1976-01-01

T. E. Hulme, a vigorous opponent of romanticism in art, poetry, and philosophy, insisted that the underlying flaw of the romantic view was its rejection of the dogma of Original Sin and the fall of man. His views are explored for the significant bearing they have on the development of aesthetic insight and indirectly on value and outlook.…

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

NASA Astrophysics Data System (ADS)

Jude, Emma; Johanson, Zerina; Kearsley, Anton; Friedman, Matt

2014-08-01

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.

Notes on "bioethics and sin" by Jean-Francois Collange.

PubMed

Cozby, Dimitri

2005-08-01

Placing the notion of sin in the context of a meontic account of evil, and emphasizing the effect of sin on the sinner himself, this commentary exposes the insufficiency of restricting oneself to human efforts at atonement, and of thus underemphasizing the role of Christ. Collange's claim that the teaching of "predestination" is rooted in Paul and that the doctrine of merits and indulgences is rooted in Augustine is criticized, and Luther's "forensic" understanding is linked with Augustine, rather than with Paul. Collange's reduction of the concern for holiness to respect and trust is contrasted with holiness's essential context of loving unification with God. The commentary closes by exposing the unsatisfactory scantiness of Collange's treatment of cloning, health-care economy, and of the evils of life.

Computer simulation of a cruise missile using brushless dc motor fin control

NASA Astrophysics Data System (ADS)

Franklin, G. C.

1985-03-01

This thesis describes a computer simulation developed in order to provide a method of establishing the potential of brushless dc motors for applications to tactical cruise missile control surface positioning. In particular, an altitude hold controller has been developed that provides an operational load test condition for the evaluation of the electromechanical actuator. A proportional integral control scheme in conjunction with tachometer feedback provides the position control for the missile tailfin surfaces. The fin control system is further imbedded in a cruise missile model to allow altitude control of the missile. The load on the fin is developed from the dynamic fluid environment that the missile will be operating in and is proportional to such factors as fin size and air density. The program written in CSMP language is suitable for parametric studies including motor and torque load characteristics, and missile and control system parameters.

Perforated fins effect on the heat transfer rate from a circular tube by using wind tunnel: An experimental view

NASA Astrophysics Data System (ADS)

Ahmadi Nadooshan, Afshin; Kalbasi, Rasool; Afrand, Masoud

2018-04-01

Perforated fins effects on the heat transfer rate of a circular tube are examined experimentally. An experimental system is set up through the wind tunnel and equipped with necessary measurement tools. Hot water passes through the finned tube and heat transfers to the fin-side air created using the wind tunnel with different velocities. Two fin sets of identical weight are installed on a circular tube with different outer diameters of 22 and 26 mm. The experiments are conducted at two different mass flow rates of the hot water and six Reynolds number of external air flow. Considering the four finned tubes and one no finned tube, a total of 60 tests are conducted. Results showed that with increasing the internal or external flow rates, the effect of larger cross-sectional area is greater. By opening holes on the fins, in addition to weight loss, the maximum heat transfer rate for perforated fins increases by 8.78% and 9.23% respectively for mass flow rates of 0.05 and 0.1 kg/s at low external Reynolds number. While, at high external Reynolds number, the holes reduces heat transfer by 8.4% and 10.6% for mass flow rates of 0.05 and 0.1 kg/s, respectively.

Performance enhancement in uniaxially tensile stressed GeSn n-channel fin tunneling field-effect transistor: Impact of stress direction

NASA Astrophysics Data System (ADS)

Wang, Hongjuan; Han, Genquan; Jiang, Xiangwei; Liu, Yan; Zhang, Chunfu; Zhang, Jincheng; Hao, Yue

2017-04-01

In this work, the boosting effect on the performance of GeSn n-channel fin tunneling FET (nFinTFET) enabled by uniaxial tensile stress is investigated theoretically. As the fin rotates within the (001) plane, the uniaxial tensile stress is always along its direction. The electrical characteristics of tensile-stressed GeSn nFinTFETs with point and line tunneling modes are computed utilizing the technology computer aided design (TCAD) simulator in which the dynamic nonlocal band-to-band tunneling (BTBT) algorithm is employed. In comparison with the relaxed devices, tensile-stressed GeSn nFinTFETs achieve a substantial enhancement in band-to-band tunneling generation rate (G BTBT) and on-state current I ON owing to the reduced bandgap E G induced by the tensile stress. Performance improvement of GeSn nFinTFETs induced by tensile stress demonstrates a strong dependence on channel direction and tunneling modes. Under the same magnitude of stress, line-nFinTFETs obtain a more pronounced I ON enhancement over the transistors with point tunneling mode.

Fluid-cooled heat sink with improved fin areas and efficiencies for use in cooling various devices

DOEpatents

Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant

2015-04-21

The disclosure provides a fluid-cooled heat sink having a heat transfer base and a plurality of heat transfer fins in thermal communication with the heat transfer base, where the heat transfer base and the heat transfer fins form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

A Study on Aspect Ratio of Heat Dissipation Fin for the Heat Dissipation Performance of Ultra Constant Discharge Lamp

NASA Astrophysics Data System (ADS)

Ko, Dong Guk; Cong Ge, Jun; Im, Ik Tae; Choi, Nag Jung; Kim, Min Soo

2018-01-01

In this study, we analyzed the heat dissipation performance of UCD lamp ballast fin with various aspect ratios. The minimum grid size was 0.02 mm and the number of grid was approximately 11,000. In order to determine the influence of the aspect ratio on the heat dissipation performance of UCD lamp ballast fin, the heat transfer area of the fin was kept constant at 4 mm2. The aspect ratios of the fin were 2 mm: 2 mm (basic model), 1.5 mm: 2.7 mm and 2.7 mm: 1.5 mm, respectively. The heat flux and heat flux time at fin were kept constant at 1×105 W/m2 and 10 seconds, respectively. The heat dissipation performance by the fin was the best at an aspect ratio of 1.5 mm: 2.7 mm.

Tunnel FinFET CMOS inverter with very low short-circuit current for ultralow-power Internet of Things application

NASA Astrophysics Data System (ADS)

Morita, Yukinori; Fukuda, Koichi; Liu, Yongxun; Mori, Takahiro; Mizubayashi, Wataru; O'uchi, Shin-ichi; Fuketa, Hiroshi; Otsuka, Shintaro; Migita, Shinji; Masahara, Meishoku; Endo, Kazuhiko; Ota, Hiroyuki; Matsukawa, Takashi

2017-04-01

We have demonstrated the operation of a CMOS inverter consisting of Si tunnel FinFETs. Both p- and n-type tunnel FinFETs are successfully fabricated and operated on the same SOI wafer. The current mismatch between p- and n-type tunnel FETs is compensated by tuning the number of fin channels. Very low short-circuit current and clear voltage input-output characteristics are obtained. The thin epitaxial channel in the tunnel FinFETs effectively increases the drain current and accordingly reduces the drain capacitance, which could help high-performance tunnel FET CMOS inverter operation.

Experimental study on heat transfer performance of fin-tube exchanger and PSHE for waste heat recovery

NASA Astrophysics Data System (ADS)

Chen, Ting; Bae, Kyung Jin; Kwon, Oh Kyung

2018-02-01

In this paper, heat transfer characteristics of fin-tube heat exchanger and primary surface heat exchanger (PSHE) used in waste heat recovery were investigated experimentally. The flow in the fin-tube heat exchanger is cross flow and in PSHE counter flow. The variations of friction factor and Colburn j factor with air mass flow rate, and Nu number with Re number are presented. Various comparison methods are used to evaluate heat transfer performance, and the results show that the heat transfer rate of the PSHE is on average 17.3% larger than that of fin-tube heat exchanger when air mass flow rate is ranging from 1.24 to 3.45 kg/min. However, the PSHE causes higher pressure drop, and the fin-tube heat exchanger has a wider application range which leads to a 31.7% higher value of maximum heat transfer rate compared to that of the PSHE. Besides, under the same fan power per unit frontal surface, a higher heat transfer rate value is given in the fin-tube heat exchanger.

Heterochronic shift in Hox-mediated activation of sonic hedgehog leads to morphological changes during fin development.

PubMed

Sakamoto, Koji; Onimaru, Koh; Munakata, Keijiro; Suda, Natsuno; Tamura, Mika; Ochi, Haruki; Tanaka, Mikiko

2009-01-01

We explored the molecular mechanisms of morphological transformations of vertebrate paired fin/limb evolution by comparative gene expression profiling and functional analyses. In this study, we focused on the temporal differences of the onset of Sonic hedgehog (Shh) expression in paired appendages among different vertebrates. In limb buds of chick and mouse, Shh expression is activated as soon as there is a morphological bud, concomitant with Hoxd10 expression. In dogfish (Scyliorhinus canicula), however, we found that Shh was transcribed late in fin development, concomitant with Hoxd13 expression. We utilized zebrafish as a model to determine whether quantitative changes in hox expression alter the timing of shh expression in pectoral fins of zebrafish embryos. We found that the temporal shift of Shh activity altered the size of endoskeletal elements in paired fins of zebrafish and dogfish. Thus, a threshold level of hox expression determines the onset of shh expression, and the subsequent heterochronic shift of Shh activity can affect the size of the fin endoskeleton. This process may have facilitated major morphological changes in paired appendages during vertebrate limb evolution.

ZnO-based multiple channel and multiple gate FinMOSFETs

NASA Astrophysics Data System (ADS)

Lee, Ching-Ting; Huang, Hung-Lin; Tseng, Chun-Yen; Lee, Hsin-Ying

2016-02-01

In recent years, zinc oxide (ZnO)-based metal-oxide-semiconductor field-effect transistors (MOSFETs) have attracted much attention, because ZnO-based semiconductors possess several advantages, including large exciton binding energy, nontoxicity, biocompatibility, low material cost, and wide direct bandgap. Moreover, the ZnO-based MOSFET is one of most potential devices, due to the applications in microwave power amplifiers, logic circuits, large scale integrated circuits, and logic swing. In this study, to enhance the performances of the ZnO-based MOSFETs, the ZnObased multiple channel and multiple gate structured FinMOSFETs were fabricated using the simple laser interference photolithography method and the self-aligned photolithography method. The multiple channel structure possessed the additional sidewall depletion width control ability to improve the channel controllability, because the multiple channel sidewall portions were surrounded by the gate electrode. Furthermore, the multiple gate structure had a shorter distance between source and gate and a shorter gate length between two gates to enhance the gate operating performances. Besides, the shorter distance between source and gate could enhance the electron velocity in the channel fin structure of the multiple gate structure. In this work, ninety one channels and four gates were used in the FinMOSFETs. Consequently, the drain-source saturation current (IDSS) and maximum transconductance (gm) of the ZnO-based multiple channel and multiple gate structured FinFETs operated at a drain-source voltage (VDS) of 10 V and a gate-source voltage (VGS) of 0 V were respectively improved from 11.5 mA/mm to 13.7 mA/mm and from 4.1 mS/mm to 6.9 mS/mm in comparison with that of the conventional ZnO-based single channel and single gate MOSFETs.

Impact of residual defects caused by extension ion implantation in FinFETs on parasitic resistance and its fluctuation

NASA Astrophysics Data System (ADS)

Matsukawa, Takashi; Liu, Yongxun; Mori, Takahiro; Morita, Yukinori; Otsuka, Shintaro; O'uchi, Shin-ichi; Fuketa, Hiroshi; Migita, Shinji; Masahara, Meishoku

2017-06-01

The influence of extension doping on parasitic resistance and its variability has been investigated for FinFETs. Electrical characterization of FinFETs and crystallinity evaluation of the doped fin structure are carried out for different fin thicknesses and different donor species for ion implantation, i.e., As and P. Reducing the fin thickness and the use of donor species with a larger mass cause serious degradation in the variability and median value of the parasitic resistance. Crystallinity evaluation by transmission electron microscope reveals that significant crystal defects remain after dopant activation annealing for the cases of smaller fin thickness and the implanted dopant with a larger mass. The unrecovered defects cause serious degradation in the parasitic resistance and its variability. In 1998, he joined the Electrotechnical Laboratory, which is former organization of National Institute of Advanced Industrial Science and Technology (AIST). He has been working on development of front-end process technology, variability issues of the FinFETs and technologies for suppressing the variability. He is now a group leader of the AIST and leads the research on the silicon-based CMOS devices. He is a member of the IEEE Electron Devices Society, and the Japan Society of Applied Physics.

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater

PubMed Central

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2013-01-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s−1. Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s−1 with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency. PMID:25685486

Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater.

PubMed

Chabane, Foued; Moummi, Noureddine; Benramache, Said

2014-03-01

The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s(-1). Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s(-1) with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency.

Local endwall heat/mass-transfer distributions in pin fin channels

NASA Astrophysics Data System (ADS)

Lau, S. C.; Kim, Y. S.; Han, J. C.

1987-10-01

Naphthalene sublimination experiments were conducted to study the effects of the pin configuration, the pin length-to-diameter ratio, and the entrance length on local endwall heat/mass transfer in a channel with short pin fins (pin length-to-diameter ratios of 0.5 and 1.0). The detailed distributions of the local endwall heat/mass-transfer coefficient were obtained for staggered and aligned arrays of pin fins, for the spanwise pin spacing-to-diameter ratio of 2.5, and for streamwise pin spacing-to-diameter ratios of 1.25 and 2.5. The Reynolds numbers were kept at about 33,000. Overall- and row-averaged Nusselt numbers compared very well with those from previous heat-transfer studies.

Musculoskeletal anatomy of the pelvic fin of Polypterus: implications for phylogenetic distribution and homology of pre- and postaxial pelvic appendicular muscles.

PubMed

Molnar, Julia L; Johnston, Peter S; Esteve-Altava, Borja; Diogo, Rui

2017-04-01

As a member of the most basal clade of extant ray-finned fishes (actinopterygians) and of one of the most basal clades of osteichthyans (bony fishes + tetrapods), Polypterus can provide insights into the ancestral anatomy of both ray-finned and lobe-finned fishes, including those that gave rise to tetrapods. The pectoral fin of Polypterus has been well described but, surprisingly, neither the bones nor the muscles of the pelvic fin are well known. We stained and dissected the pelvic fin of Polypterus senegalus and Polypterus delhezi to offer a detailed description of its musculoskeletal anatomy. In addition to the previously described adductor and abductor muscles, we found preaxial and postaxial muscles similar to those in the pectoral fin of members of this genus. The presence of pre- and postaxial muscles in both the pectoral and pelvic fins of Polypterus, combined with recent descriptions of similar muscles in the lobe-finned fishes Latimeria and Neoceratodus, suggests that they were present in the most recent common ancestor of bony fishes. These results have crucial implications for the evolution of appendicular muscles in both fish and tetrapods. © 2016 Anatomical Society.

Design and dynamic modeling of electrorheological fluid-based variable-stiffness fin for robotic fish

NASA Astrophysics Data System (ADS)

Bazaz Behbahani, Sanaz; Tan, Xiaobo

2017-08-01

Fish actively control their stiffness in different swimming conditions. Inspired by such an adaptive behavior, in this paper we study the design, prototyping, and dynamic modeling of compact, tunable-stiffness fins for robotic fish, where electrorheological (ER) fluid serves as the enabling element. A multi-layer composite fin with an ER fluid core is prototyped and utilized to investigate the influence of electrical field on its performance. Hamilton's principle is used to derive the dynamic equations of motion of the flexible fin, and Lighthill's large-amplitude elongated-body theory is adopted to estimate the hydrodynamic force when the fin undergoes base-actuated rotation. The dynamic equations are then discretized using the finite element method, to obtain an approximate numerical solution. Experiments are conducted on the prototyped flexible ER fluid-filled beam for parameter identification and validation of the proposed model, and for examining the effectiveness of electrically controlled stiffness tuning. In particular, it is found that the natural frequency is increased by almost 40% when the applied electric field changes from 0 to 1.5× {10}6 {{V}} {{{m}}}-1.

A Method for Oscillation Errors Restriction of SINS Based on Forecasted Time Series.

PubMed

Zhao, Lin; Li, Jiushun; Cheng, Jianhua; Jia, Chun; Wang, Qiufan

2015-07-17

Continuity, real-time, and accuracy are the key technical indexes of evaluating comprehensive performance of a strapdown inertial navigation system (SINS). However, Schuler, Foucault, and Earth periodic oscillation errors significantly cut down the real-time accuracy of SINS. A method for oscillation error restriction of SINS based on forecasted time series is proposed by analyzing the characteristics of periodic oscillation errors. The innovative method gains multiple sets of navigation solutions with different phase delays in virtue of the forecasted time series acquired through the measurement data of the inertial measurement unit (IMU). With the help of curve-fitting based on least square method, the forecasted time series is obtained while distinguishing and removing small angular motion interference in the process of initial alignment. Finally, the periodic oscillation errors are restricted on account of the principle of eliminating the periodic oscillation signal with a half-wave delay by mean value. Simulation and test results show that the method has good performance in restricting the Schuler, Foucault, and Earth oscillation errors of SINS.

A Method for Oscillation Errors Restriction of SINS Based on Forecasted Time Series

PubMed Central

Zhao, Lin; Li, Jiushun; Cheng, Jianhua; Jia, Chun; Wang, Qiufan

2015-01-01

Continuity, real-time, and accuracy are the key technical indexes of evaluating comprehensive performance of a strapdown inertial navigation system (SINS). However, Schuler, Foucault, and Earth periodic oscillation errors significantly cut down the real-time accuracy of SINS. A method for oscillation error restriction of SINS based on forecasted time series is proposed by analyzing the characteristics of periodic oscillation errors. The innovative method gains multiple sets of navigation solutions with different phase delays in virtue of the forecasted time series acquired through the measurement data of the inertial measurement unit (IMU). With the help of curve-fitting based on least square method, the forecasted time series is obtained while distinguishing and removing small angular motion interference in the process of initial alignment. Finally, the periodic oscillation errors are restricted on account of the principle of eliminating the periodic oscillation signal with a half-wave delay by mean value. Simulation and test results show that the method has good performance in restricting the Schuler, Foucault, and Earth oscillation errors of SINS. PMID:26193283

Sin1, a Mutation Affecting Female Fertility in Arabidopsis, Interacts with Mod1, Its Recessive Modifier

PubMed Central

Lang, J. D.; Ray, S.; Ray, A.

1994-01-01

In Arabidopsis thaliana, a mutation in the SIN1 gene causes aberrant ovule development and female-specific sterility. The effect of the sin1 mutation is polymorphic and pleiotropic in different genetic backgrounds. The polymorphism concerns morphology of the mutant ovules. The pleiotropism involves internodal distance and inflorescence initiation time. The particular ovule phenotype and the length of internodes are dependent on an interaction of sin1 with a second recessive gene, which we term mod1. The recessive mod1 allele in a homozygous sin1 mutant plant reduces internode length and ovule integument size. The mutation sin1, but not mod1, has a demonstrable effect on ovule morphology when acting idependently. In our crosses mod1 was inseparably linked to the well known mutation erecta that is known to cause a reduction in internode and pedicel lengths. PMID:7982564

Taphonomic evidence for high-speed adapted fins in thunniform ichthyosaurs.

PubMed

Lingham-Soliar, Theagarten; Plodowski, Gerhard

2007-01-01

Ichthyosaurs have been compared with the fast-swimming thunniform groups of marine vertebrates, tuna, lamnid sharks, and dolphins, based on similarity of shape of the body and locomotory organs. In addition to shape, high-tensile stiffness of the control surfaces has been shown to be essential in maximizing hydrodynamic efficiency in extant thunniform swimmers. To date, there has been no evidence of a stiffening support system for the dorsal fin and dorsal lobe of the caudal fin in ichthyosaurs, the sole stiffening structure of the ventral lobe being an extension of the vertebral column along its leading edge. Stenopterygius SMF 457 is arguably the best soft-tissue preserved ichthyosaur specimen known. Here, we examine soft-tissue preservation in this specimen in the control surfaces and provide the first evidence of a complex architecture of stiff fibers in the dorsal and caudal fins. We find by comparisons and by analogy that these fibers provided a remarkable mechanism for high tensile stiffness and efficiency of the locomotory organs virtually identical to that of the great white shark, Carcharodon carcharias. It is the first mechanostructural study of the control surfaces of a Jurassic ichthyosaur that adds essential evidence in support of the view that these forms were high-speed thunniform swimmers.

Taphonomic evidence for high-speed adapted fins in thunniform ichthyosaurs

NASA Astrophysics Data System (ADS)

Lingham-Soliar, Theagarten; Plodowski, Gerhard

2007-01-01

Ichthyosaurs have been compared with the fast-swimming thunniform groups of marine vertebrates, tuna, lamnid sharks, and dolphins, based on similarity of shape of the body and locomotory organs. In addition to shape, high-tensile stiffness of the control surfaces has been shown to be essential in maximizing hydrodynamic efficiency in extant thunniform swimmers. To date, there has been no evidence of a stiffening support system for the dorsal fin and dorsal lobe of the caudal fin in ichthyosaurs, the sole stiffening structure of the ventral lobe being an extension of the vertebral column along its leading edge. Stenopterygius SMF 457 is arguably the best soft-tissue preserved ichthyosaur specimen known. Here, we examine soft-tissue preservation in this specimen in the control surfaces and provide the first evidence of a complex architecture of stiff fibers in the dorsal and caudal fins. We find by comparisons and by analogy that these fibers provided a remarkable mechanism for high tensile stiffness and efficiency of the locomotory organs virtually identical to that of the great white shark, Carcharodon carcharias. It is the first mechanostructural study of the control surfaces of a Jurassic ichthyosaur that adds essential evidence in support of the view that these forms were high-speed thunniform swimmers.

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

PubMed

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. © 2015 The Author(s).

Assessment of the dorsal fin spine for chimaeroid (Holocephali: Chimaeriformes) age estimation.

PubMed

Barnett, L A K; Ebert, D A; Cailliet, G M

2009-10-01

Previous attempts to age chimaeroids have not rigorously tested assumptions of dorsal fin spine growth dynamics. Here, novel imaging and data-analysis techniques revealed that the dorsal fin spine of the spotted ratfish Hydrolagus colliei is an unreliable structure for age estimation. Variation among individuals in the relationship between spine width and distance from the spine tip indicated that the technique of transverse sectioning may impart imprecision and bias to age estimates. The number of growth-band pairs observed by light microscopy in the inner dentine layer was not a good predictor of body size. Mineral density gradients, indicative of growth zones, were absent in the dorsal fin spine of H. colliei, decreasing the likelihood that the bands observed by light microscopy represent a record of growth with consistent periodicity. These results indicate that the hypothesis of aseasonal growth remains plausible and it should not be assumed that chimaeroid age is quantifiable by standard techniques.

The Species and Origin of Shark Fins in Taiwan's Fishing Ports, Markets, and Customs Detention: A DNA Barcoding Analysis.

PubMed

Chuang, Po-Shun; Hung, Tzu-Chiao; Chang, Hung-An; Huang, Chien-Kang; Shiao, Jen-Chieh

2016-01-01

The increasing consumption of shark products, along with the shark's fishing vulnerabilities, has led to the decrease in certain shark populations. In this study we used a DNA barcoding method to identify the species of shark landings at fishing ports, shark fin products in retail stores, and shark fins detained by Taiwan customs. In total we identified 23, 24, and 14 species from 231 fishing landings, 316 fin products, and 113 detained shark fins, respectively. All the three sample sources were dominated by Prionace glauca, which accounted for more than 30% of the collected samples. Over 60% of the species identified in the fin products also appeared in the port landings, suggesting the domestic-dominance of shark fin products in Taiwan. However, international trade also contributes a certain proportion of the fin product markets, as four species identified from the shark fin products are not found in Taiwan's waters, and some domestic-available species were also found in the customs-detained sample. In addition to the species identification, we also found geographical differentiation in the cox1 gene of the common thresher sharks (Alopias vulpinus), the pelagic thresher shark (A. pelagicus), the smooth hammerhead shark (Sphyrna zygaena), and the scalloped hammerhead shark (S. lewini). This result might allow fishing authorities to more effectively trace the origins as well as enforce the management and conservation of these sharks.

Annular convective-radiative fins with a step change in thickness, and temperature-dependent thermal conductivity and heat transfer coefficient

NASA Astrophysics Data System (ADS)

Barforoush, M. S. M.; Saedodin, S.

2018-01-01

This article investigates the thermal performance of convective-radiative annular fins with a step reduction in local cross section (SRC). The thermal conductivity of the fin's material is assumed to be a linear function of temperature, and heat transfer coefficient is assumed to be a power-law function of surface temperature. Moreover, nonzero convection and radiation sink temperatures are included in the mathematical model of the energy equation. The well-known differential transformation method (DTM) is used to derive the analytical solution. An exact analytical solution for a special case is derived to prove the validity of the obtained results from the DTM. The model provided here is a more realistic representation of SRC annular fins in actual engineering practices. Effects of many parameters such as conduction-convection parameters, conduction-radiation parameter and sink temperature, and also some parameters which deal with step fins such as thickness parameter and dimensionless parameter describing the position of junction in the fin on the temperature distribution of both thin and thick sections of the fin are investigated. It is believed that the obtained results will facilitate the design and performance evaluation of SRC annular fins.

Pegasus ICON Fin Installation

NASA Image and Video Library

2017-07-08

Technicians install the starboard fin on the Orbital ATK Pegasus XL rocket July 8, 2017, inside Building 1555 at Vandenberg Air Force Base in California. The Pegasus rocket is being prepared for NASA's Ionospheric Connection Explorer, or ICON, mission. ICON will launch on June 15 from Kwajalein Atoll in the Marshall Islands (June 14 in the continental United States) on Orbital ATK's Pegasus XL rocket, which is attached to the company's L-1011 Stargazer aircraft. ICON will study the frontier of space - the dynamic zone high in Earth's atmosphere where terrestrial weather from below meets space weather above. The explorer will help determine the physics of Earth's space environment and pave the way for mitigating its effects on our technology, communications systems and society.

Mixed convection flow of nanofluid in a square enclosure with an intruded rectangular fin

NASA Astrophysics Data System (ADS)

Cong, Ran; Zhou, Xuanyu; De Souza Machado, Bruno; Das, Prodip K.

2016-07-01

Mixed convection flow in enclosures has been a subject of interest for many years due to their ever increasing applications in solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. In comparison, little effort has been given to the problem of mixed convection in enclosures filled with nanofluids, while the addition of nanoparticles in a fluid base to alter specific material properties is considered a feasible solution for many heat transfer problems. Mixed convection of nanofluids is a challenging problem as the addition of nanoparticles changes the fluid's thermo-physical properties as well as due to the complex interactions among inertia, viscous, and buoyancy forces. In this study, a two-dimensional steady-state numerical model has been developed to investigate mixed convection flow of nanofluids in a square enclosure with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the Constructal design. The model has been developed using ANSYS-FLUENT for various fin geometries. Flow fields, temperature fields, and heat transfer rates are examined for different values of Rayleigh and Reynolds numbers for several geometries of the fin with the aim of maximizing the heat transfer from the fin to the surrounding flow. Outcome of this study provides important insight into the heat transfer behavior of nanofluids, which will help in developing novel geometries with enhanced and controlled heat transfer for solar collectors and electronic devices.

Mixed convection flow of nanofluid in a square enclosure with an intruded rectangular fin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cong, Ran; Zhou, Xuanyu; De Souza Machado, Bruno

Mixed convection flow in enclosures has been a subject of interest for many years due to their ever increasing applications in solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. In comparison, little effort has been given to the problem of mixed convection in enclosures filled with nanofluids, while the addition of nanoparticles in a fluid base to alter specific material properties is considered a feasible solution for many heat transfer problems. Mixed convection of nanofluids is a challenging problem as the addition of nanoparticles changes the fluid’s thermo-physical properties as well as due to the complex interactionsmore » among inertia, viscous, and buoyancy forces. In this study, a two-dimensional steady-state numerical model has been developed to investigate mixed convection flow of nanofluids in a square enclosure with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the Constructal design. The model has been developed using ANSYS-FLUENT for various fin geometries. Flow fields, temperature fields, and heat transfer rates are examined for different values of Rayleigh and Reynolds numbers for several geometries of the fin with the aim of maximizing the heat transfer from the fin to the surrounding flow. Outcome of this study provides important insight into the heat transfer behavior of nanofluids, which will help in developing novel geometries with enhanced and controlled heat transfer for solar collectors and electronic devices.« less

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins.

PubMed

Stan, Gheorghe; Gates, Richard S; Hu, Qichi; Kjoller, Kevin; Prater, Craig; Jit Singh, Kanwal; Mays, Ebony; King, Sean W

2017-01-01

The exploitation of nanoscale size effects to create new nanostructured materials necessitates the development of an understanding of relationships between molecular structure, physical properties and material processing at the nanoscale. Numerous metrologies capable of thermal, mechanical, and electrical characterization at the nanoscale have been demonstrated over the past two decades. However, the ability to perform nanoscale molecular/chemical structure characterization has only been recently demonstrated with the advent of atomic-force-microscopy-based infrared spectroscopy (AFM-IR) and related techniques. Therefore, we have combined measurements of chemical structures with AFM-IR and of mechanical properties with contact resonance AFM (CR-AFM) to investigate the fabrication of 20-500 nm wide fin structures in a nanoporous organosilicate material. We show that by combining these two techniques, one can clearly observe variations of chemical structure and mechanical properties that correlate with the fabrication process and the feature size of the organosilicate fins. Specifically, we have observed an inverse correlation between the concentration of terminal organic groups and the stiffness of nanopatterned organosilicate fins. The selective removal of the organic component during etching results in a stiffness increase and reinsertion via chemical silylation results in a stiffness decrease. Examination of this effect as a function of fin width indicates that the loss of terminal organic groups and stiffness increase occur primarily at the exposed surfaces of the fins over a length scale of 10-20 nm. While the observed structure-property relationships are specific to organosilicates, we believe the combined demonstration of AFM-IR with CR-AFM should pave the way for a similar nanoscale characterization of other materials where the understanding of such relationships is essential.

Copper vertical micro dendrite fin arrays and their superior boiling heat transfer capability

NASA Astrophysics Data System (ADS)

Wang, Ya-Qiao; Lyu, Shu-Shen; Luo, Jia-Li; Luo, Zhi-Yong; Fu, Yuan-Xiang; Heng, Yi; Zhang, Jian-Hui; Mo, Dong-Chuan

2017-11-01

Micro pin fin arrays have been widely used in electronic cooling, micro reactors, catalyst support, and wettability modification and so on, and a facile way to produce better micro pin fin arrays is demanded. Herein, a simple electrochemical method has been developed to fabricate copper vertical micro dendrite fin arrays (Cu-VMDFA) with controllable shapes, number density and height. High copper sulphate concentration is one key point to make the dendrite stand vertically. Besides, the applied current should rise at an appropriate rate to ensure the copper dendrite can grow vertically on its own. The Cu-VMDFA can significantly enhance the heat transfer coefficient by approximately twice compared to the plain copper surface. The Cu-VMDFA may be widely used in boiling heat transfer areas such as nuclear power plants, electronic cooling, heat exchangers, and so on.

Fin-fishes in Yorùbá natural healing practices from southwest Nigeria.

PubMed

Sowunmi, Akindayo A

2007-08-15

Natural healing treatment recipes from southwest Nigeria were examined for fin-fishes of ethnomedical importance. Fifteen families of 19 genera were identified with members found either in marine, fresh or brackish waters. Two thousand two hundred and eighty-five recipes were examined, 9.11% contained fin-fish or its derivative as component. Fertility/conception-related medical conditions have highest proportion of recipes (26.26%) with fish/derivatives as inputs. One hundred and forty-one recipes were examined for fertility-related conditions, the highest for any medical condition during this study. Clarias sp. (Clariidae) (catfish) recorded the highest rate of use (78.94%) followed by Malapterurus electricus (Malapteruridae) (electric catfish) with 5.26%. Fin-fishes/derivatives were observed to have both physical and spiritual activities in treatment preparations. Most of the fish species were in need of conservation interventions.

Analytical study of temperature distribution in a rectangular porous fin considering both insulated and convective tip

NASA Astrophysics Data System (ADS)

Deshamukhya, Tuhin; Bhanja, Dipankar; Nath, Sujit; Maji, Ambarish; Choubey, Gautam

2017-07-01

The following study is concerned with determination of temperature distribution of porous fins under convective and insulated tip conditions. The authors have made an effort to study the effect of various important parameters involved in the transfer of heat through porous fins as well as the temperature distribution along the fin length subjected to both convective as well as insulated ends. The non-linear equation obtained has been solved by Adomian Decomposition method and validated with a numerical scheme called Finite Difference method by using a central difference scheme and Gauss Siedel Iterative method.

Development of the activated diffusion brazing process for fabrication of finned shell to strut turbine blades

NASA Technical Reports Server (NTRS)

Wilbers, L. G.; Berry, T. F.; Kutchera, R. E.; Edmonson, R. E.

1971-01-01

The activated diffusion brazing process was developed for attaching TD-NiCr and U700 finned airfoil shells to matching Rene 80 struts obstructing the finned cooling passageways. Creep forming the finned shells to struts in combination with precise preplacement of brazing alloy resulted in consistently sound joints, free of cooling passageway clogging. Extensive tensile and stress rupture testing of several joint orientation at several temperatures provided a critical assessment of joint integrity of both material combinations. Trial blades of each material combination were fabricated followed by destructive metallographic examination which verified high joint integrity.

Characteristics of fin whale vocalizations recorded on instruments in the northeast Pacific Ocean

NASA Astrophysics Data System (ADS)

Weirathmueller, Maria Michelle Josephine

This thesis focuses on fin whale vocalizations recorded on ocean bottom seismometers (OBSs) in the Northeast Pacific Ocean, using data collected between 2003 and 2013. OBSs are a valuable, and largely untapped resource for the passive acoustic monitoring of large baleen whales. This dissertation is divided into three parts, each of which uses the recordings of fin whale vocalizations to better understand their calling behaviors and distributions. The first study describes the development of a technique to extract source levels of fin whale vocalizations from OBS recordings. Source levels were estimated using data collected on a network of eight OBSs in the Northeast Pacific Ocean. The acoustic pressure levels measured at the instruments were adjusted for the propagation path between the calling whales and the instruments using the call location and estimating losses along the acoustic travel path. A total of 1241 calls were used to estimate an average source level of 189 +/-5.8 dB re 1uPa 1m. This variability is largely attributed to uncertainties in the horizontal and vertical position of the fin whale at the time of each call, and the effect of these uncertainties on subsequent calculations. The second study describes a semi-automated method for obtaining horizontal ranges to vocalizing fin whales using the timing and relative amplitude of multipath arrivals. A matched filter is used to detect fin whale calls and pick the relative times and amplitudes of multipath arrivals. Ray-based propagation models are used to predict multipath times and amplitudes as function of range. Because the direct and first multiple arrivals are not always observed, three hypotheses for the paths of the observed arrivals are considered; the solution is the hypothesis and range that optimizes the fit to the data. Ray-theoretical amplitudes are not accurate and solutions are improved by determining amplitudes from the observations using a bootstrap method. Data from ocean bottom

Solution of mixed convection heat transfer from isothermal in-line fins

NASA Technical Reports Server (NTRS)

Khalilollahi, Amir

1993-01-01

Transient and steady state combined natural and forced convective flows over two in-line finite thickness fins (louvers) in a vertical channel are numerically solved using two methods. The first method of solution is based on the 'Simple Arbitrary Lagrangian Eulerian' (SALE) technique which incorporates mainly two computational phases: (1) a Lagrangian phase in which the velocity field is updated by the effects of all forces, and (2) an Eulerian phase that executes all advective fluxes of mass, momentum and energy. The second method of solution uses the finite element code entitled FIDAP. In the first part, comparison of the results by FIDAP, SALE, and available experimental work were done and discussed for steady state forced convection over louvered fins. Good agreements were deduced between the three sets of results especially for the flow over a single fin. In the second part and in the absence of experimental literature, the numerical predictions were extended to the transient transports and to the opposing flow where pressure drop is reversed. Results are presented and discussed for heat transfer and pressure drop in assisting and opposing mixed convection flows.

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

PubMed

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

2016-02-08

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.

Analysis of a novel device-level SINS/ACFSS deeply integrated navigation method

NASA Astrophysics Data System (ADS)

Zhang, Hao; Qin, Shiqiao; Wang, Xingshu; Jiang, Guangwen; Tan, Wenfeng; Wu, Wei

2017-02-01

The combination of the strap-down inertial navigation system(SINS) and the celestial navigation system(CNS) is one of the popular measures to constitute the integrated navigation system. A star sensor(SS) is used as a precise attitude determination device in CNS. To solve the problem that the star image obtained by SS is motion-blurred under dynamic conditions, the attitude-correlated frames(ACF) approach is presented and the star sensor which works based on ACF approach is named ACFSS. Depending on the ACF approach, a novel device-level SINS/ACFSS deeply integrated navigation method is proposed in this paper. Feedback to the ACF process from the error of the gyro is one of the typical characters of the SINS/CNS deeply integrated navigation method. Herein, simulation results have verified its validity and efficiency in improving the accuracy of gyro and it can be proved that this method is feasible.

Estudio multifrecuencia del medio interestelar cercano a HD 192281

NASA Astrophysics Data System (ADS)

Arnal, E. M.; Cappa, C.; Cichowolski, S.; Pineault, S.; St-Louis, N.

Una de las causas que modifica la estructura y dinámica del medio interestelar es la acción que los vientos de las estrellas de gran masa ejercen sobre el mismo. En este trabajo, mediante el uso de datos interferométricos obtenidos en la banda de radio en la transición de 21-cm del Hidrógeno neutro y de imágenes de la emisión de continuo en las bandas de 408 y 1420 MHz, de imágenes HIRES del satélite IRAS en 60 y 100 micrones, y de observaciones de continuo obtenidas con radiotelescopios de disco simple en 2695, 4850 y 8350 MHz se ha realizado un estudio multifrecuencia de los efectos que los vientos estelares de HD 192281, una estrella de tipo espectral O5 Vn((f))p, han tenido sobre el medio interestelar que rodea a la misma.

Estudio multifrecuencia del medio interestelar cercano a HD 192281

NASA Astrophysics Data System (ADS)

Arnal, E. M.; Cappa, C. E.; Cichowolski, S.; Pineault, S.; St-Louis, N.

Una de las causas que modifica la estructura y dinámica del medio interestelar es la acción que los vientos de las estrellas de gran masa ejercen sobre el mismo. En este trabajo, mediante el uso de datos interferométricos obtenidos en la banda de radio en la transición de λ˜21-cm del hidrógeno neutro y de imágenes de la emisión de continuo en las bandas de 408 y 1420 MHz, de imágenes HIRES del satélite IRAS en 60 y 100μm, y de observaciones de continuo obtenidas con radiotelescopios de disco simple en 2695, 4850 y 8350 MHz se ha realizado un estudio multifrecuencia de los efectos que los vientos estelares de HD 192281, una estrella de tipo espectral O5,Vn((f))p, han tenido sobre el medio interestelar que rodea a la misma.

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

PubMed Central

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

Transcriptional co-repressor SIN3A silencing rescues decline in memory consolidation during scopolamine-induced amnesia.

PubMed

Srivas, Sweta; Thakur, Mahendra K

2018-05-01

Epigenetic modifications through methylation of DNA and acetylation of histones modulate neuronal gene expression and regulate long-term memory. Earlier we demonstrated that scopolamine-induced decrease in memory consolidation is correlated with enhanced expression of hippocampal DNA methyltransferase 1 (DNMT1) and histone deacetylase 2 (HDAC2) in mice. DNMT1 and HDAC2 act together by recruiting a co-repressor complex and deacetylating the chromatin. The catalytic activity of HDACs is mainly dependent on its incorporation into multiprotein co-repressor complexes, among which SIN3A-HDAC2 co-repressor is widely studied to regulate synaptic plasticity. However, the involvement of co-repressor complex in regulating memory loss or amnesia is unexplored. This study examines the role of co-repressor SIN3A in scopolamine-induced amnesia through epigenetic changes in the hippocampus. Scopolamine treatment remarkably enhanced hippocampal SIN3A expression in mice. To prevent such increase in SIN3A expression, we used hippocampal infusion of SIN3A-siRNA and assessed the effect of SIN3A silencing on scopolamine-induced amnesia. Silencing of SIN3A in amnesic mice reduced the binding of HDAC2 at neuronal immediate early genes (IEGs) promoter, but did not change the expression of HDAC2. Furthermore, it increased acetylation of H3K9 and H3K14 at neuronal IEGs (Arc, Egr1, Homer1 and Narp) promoter, prevented scopolamine-induced down-regulation of IEGs and improved consolidation of memory during novel object recognition task. These findings together suggest that SIN3A has a critical role in regulation of synaptic plasticity and might act as a potential therapeutic target to rescue memory decline during amnesia and other neuropsychiatric pathologies. © 2018 International Society for Neurochemistry.

Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus)

PubMed Central

Beffagna, Giorgia; Centelleghe, Cinzia; Franzo, Giovanni; Di Guardo, Giovanni; Mazzariol, Sandro

2017-01-01

Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990–‘92 and the 2006–‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells. PMID:28134317

Developmental change in the function of movement systems: transition of the pectoral fins between respiratory and locomotor roles in zebrafish.

PubMed

Hale, Melina E

2014-07-01

An animal may experience strikingly different functional demands on its body's systems through development. One way of meeting those demands is with temporary, stage-specific adaptations. This strategy requires the animal to develop appropriate morphological states or physiological pathways that address transient functional demands as well as processes that transition morphology, physiology, and function to that of the mature form. Recent research on ray-finned (actinopterygian) fishes is a developmental transition in function of the pectoral fin, thereby providing an opportunity to examine how an organism copes with changes in the roles of its morphology between stages of its life history. As larvae, zebrafish alternate their pectoral fins in coordination with the body axis during slow swimming. The movements of their fins do not appear to contribute to the production of thrust or to stability but instead exchange fluid near the body for cutaneous respiration. The morphology of the larval fin includes a simple stage-specific endoskeletal disc overlaid by fan-shaped adductor and abductor muscles. In contrast, the musculoskeletal system of the mature fin consists of a suite of muscles and bones. Fins are extended laterally during slow swimming of the adult, without the distinct, high-amplitude left-right fin alternation of the larval fin. The morphological and functional transition of the pectoral fin occurs through juvenile development. Early in this period, at about 3 weeks post-fertilization, the gills take over respiratory function, presumably freeing the fins for other roles. Kinematic data suggest that the loss of respiratory function does not lead to a rapid switch in patterns of fin movement but rather that both morphology and movement transition gradually through the juvenile stage of development. Studies relating structure to function often focus on stable systems that are arguably well adapted for the roles they play. Examining how animals navigate

Isotropic plasma etching of Ge Si and SiN x films

DOE PAGES

Henry, Michael David; Douglas, Erica Ann

2016-08-31

This study reports on selective isotropic dry etching of chemically vapor deposited (CVD) Ge thin film, release layers using a Shibaura chemical downstream etcher (CDE) with NF 3 and Ar based plasma chemistry. Relative etch rates between Ge, Si and SiN x are described with etch rate reductions achieved by adjusting plasma chemistry with O 2. Formation of oxides reducing etch rates were measured for both Ge and Si, but nitrides or oxy-nitrides created using direct injection of NO into the process chamber were measured to increase Si and SiN x etch rates while retarding Ge etching.

SinEx DB: a database for single exon coding sequences in mammalian genomes.

PubMed

Jorquera, Roddy; Ortiz, Rodrigo; Ossandon, F; Cárdenas, Juan Pablo; Sepúlveda, Rene; González, Carolina; Holmes, David S

2016-01-01

Eukaryotic genes are typically interrupted by intragenic, noncoding sequences termed introns. However, some genes lack introns in their coding sequence (CDS) and are generally known as 'single exon genes' (SEGs). In this work, a SEG is defined as a nuclear, protein-coding gene that lacks introns in its CDS. Whereas, many public databases of Eukaryotic multi-exon genes are available, there are only two specialized databases for SEGs. The present work addresses the need for a more extensive and diverse database by creating SinEx DB, a publicly available, searchable database of predicted SEGs from 10 completely sequenced mammalian genomes including human. SinEx DB houses the DNA and protein sequence information of these SEGs and includes their functional predictions (KOG) and the relative distribution of these functions within species. The information is stored in a relational database built with My SQL Server 5.1.33 and the complete dataset of SEG sequences and their functional predictions are available for downloading. SinEx DB can be interrogated by: (i) a browsable phylogenetic schema, (ii) carrying out BLAST searches to the in-house SinEx DB of SEGs and (iii) via an advanced search mode in which the database can be searched by key words and any combination of searches by species and predicted functions. SinEx DB provides a rich source of information for advancing our understanding of the evolution and function of SEGs.Database URL: www.sinex.cl. © The Author(s) 2016. Published by Oxford University Press.

Effects of Base Cavity Depth on a Free Spinning Wrap-Around Fin Missile Configuration

DTIC Science & Technology

1995-12-01

packaging problem. Current missile systems which possess wrap-around fin designs are the Army’s Multiple Launch Rocket System (MLRS) and the Hard Target...aerodynamic irregularities (2). Of particular importance to projectile designers is the side force/moment inherent to wrap-around fin configurations. During...virtual instrument programs integrated to perform all necessary aspects of calibration, data collection, and reduction. The details surrounding the design

Species composition of the international shark fin trade assessed through a retail-market survey in Hong Kong.

PubMed

Fields, Andrew T; Fischer, Gunter A; Shea, Stanley K H; Zhang, Huarong; Abercrombie, Debra L; Feldheim, Kevin A; Babcock, Elizabeth A; Chapman, Demian D

2018-04-01

The shark fin trade is a major driver of shark exploitation in fisheries all over the world, most of which are not managed on a species-specific basis. Species-specific trade information highlights taxa of particular concern and can be used to assess the efficacy of management measures and anticipate emerging threats. The species composition of the Hong Kong Special Administrative Region of China, one of the world's largest fin trading hubs, was partially assessed in 1999-2001. We randomly selected and genetically identified fin trimmings (n = 4800), produced during fin processing, from the retail market of Hong Kong in 2014-2015 to assess contemporary species composition of the fin trade. We used nonparametric species estimators to determine that at least 76 species of sharks, batoids, and chimaeras supplied the fin trade and a Bayesian model to determine their relative proportion in the market. The diversity of traded species suggests species substitution could mask depletion of vulnerable species; one-third of identified species are threatened with extinction. The Bayesian model suggested that 8 species each comprised >1% of the fin trimmings (34.1-64.2% for blue [Prionace glauca], 0.2-1.2% for bull [Carcharhinus leucas] and shortfin mako [Isurus oxyrinchus]); thus, trade was skewed to a few globally distributed species. Several other coastal sharks, batoids, and chimaeras are in the trade but poorly managed. Fewer than 10 of the species we modeled have sustainably managed fisheries anywhere in their range, and the most common species in trade, the blue shark, was not among them. Our study and approach serve as a baseline to track changes in composition of species in the fin trade over time to better understand patterns of exploitation and assess the effects of emerging management actions for these animals. © 2017 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

The hydrodynamic principle for the caudal fin shape of small aquatic animals

NASA Astrophysics Data System (ADS)

Lee, Jeongsu; Park, Yong-Jai; Cho, Kyu-Jin; Kim, Ho-Young

2014-11-01

The shape of caudal fins of small aquatic animals is completely different from that of large cruising animals like dolphin and tuna which have high aspect-ratio lunate tail. To unveil the physical principle behind natural selection of caudal fins of small aquatic animals, here we investigate the hydrodynamics of an angularly reciprocating plate as a model for the caudal fin oscillation. We find that the thrust production of a reciprocating plate at high Strouhal numbers is dominated by generation of two distinct vortical structures associated with the acceleration and deceleration of the plate regardless of their shape. Based on our observations, we construct a scaling law to predict the thrust of the flapping plate, which agrees well with the experimental data. We then seek the optimal aspect ratio to maximize thrust and efficiency of a flapping plate for fixed flapping frequency and amplitude. Thrust is maximized for the aspect ratio of approximately 0.7. We also theoretically explain the power law behaviors of the thrust and efficiency as a function of the aspect ratio.

Heat Transfer Enhancement for Finned-tube Heat Exchangers with Winglets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, James Edward; Sohal, Manohar Singh

2000-11-01

This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inversemore » heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51 x 10-3 to 14.0 x 10-3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 670 – 6300 with a duct height of 1.106 cm and a duct width-toheight ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a delta-winglet pair. Comparisons of local and average heat transfer distributions for the circular tube with and without winglets are provided. Overall mean finsurface Nusselt-number results indicate a significant level of heat transfer enhancement associated with the deployment of the winglets with the circular cylinder. At the lowest Reynolds numbers (which correspond to the laminar operating conditions of existing geothermal air-cooled condensers), the enhancement level is nearly a factor of two. At higher Reynolds numbers, the enhancement level is close to 50%.« less

Sinning against nature: the theory of background conditions

PubMed Central

Blackford, R

2006-01-01

Debates about the moral and political acceptability of particular sexual practices and new technologies often include appeals to a supposed imperative to follow nature. If nature is understood as the totality of all phenomena or as those things that are not artificial, there is little prospect of developing a successful argument to impugn interference with it or sinning against it. At the same time, there are serious difficulties with approaches that seek to identify "proper" human functioning. An alternative approach is to understand interference with nature as acting in a manner that threatens basic background conditions to human choice. Arguably, the theory of background conditions helps explain much of the hostility to practices and technologies that allegedly sin against nature. The theory does not, however, entail that appeals to nature are relevant or rational. Such appeals should be subjected to sceptical scrutiny. Indeed, the theory suggests that arguments against practices and technologies that can be seen as contrary to nature sometimes exercise a psychological attraction that is disproportional to their actual cogency. PMID:17074819

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

NASA Astrophysics Data System (ADS)

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.

Live fate-mapping of joint-associated fibroblasts visualizes expansion of cell contributions during zebrafish fin regeneration.

PubMed

Tornini, Valerie A; Thompson, John D; Allen, Raymond L; Poss, Kenneth D

2017-08-15

The blastema is a mass of progenitor cells responsible for regeneration of amputated salamander limbs and fish fins. Previous studies have indicated that resident cell sources producing the blastema contribute lineage-restricted progeny to regenerating tissue. However, these studies have labeled general cell types rather than granular cell subpopulations, and they do not explain the developmental transitions that must occur for distal structures to arise from cells with proximal identities in the appendage stump. Here, we find that regulatory sequences of tph1b , which encodes an enzyme that synthesizes serotonin, mark a subpopulation of fibroblast-like cells restricted to the joints of uninjured adult zebrafish fins. Amputation stimulates serotonin production in regenerating fin fibroblasts, yet targeted tph1b mutations abrogating this response do not disrupt fin regeneration. In uninjured animals, tph1b -expressing cells contribute fibroblast progeny that remain restricted to joints throughout life. By contrast, upon amputation, tph1b + joint cells give rise to fibroblasts that distribute across the entire lengths of regenerating fin rays. Our experiments visualize and quantify how incorporation into an appendage blastema broadens the progeny contributions of a cellular subpopulation that normally has proximodistal restrictions. © 2017. Published by The Company of Biologists Ltd.

Formation of a Ge-rich Si1-x Ge x (x > 0.9) fin epitaxial layer condensed by dry oxidation

NASA Astrophysics Data System (ADS)

Jang, Hyunchul; Kim, Byongju; Koo, Sangmo; Ko, Dae-Hong

2017-11-01

We have selectively grown an epitaxial Si0.35Ge0.65 fin layer in a 65 nm oxide trench pattern array and formed a Ge-rich Si1-x Ge x (x > 0.9) fin layer with condensed Ge using dry oxidation. During oxidation of the SiGe fin structure, we found that the compressive strain of the condensed SiGe layer was increased by about 1.3% while Ge was efficiently condensed due to a two-dimensional oxidation reaction. In this paper, we discussed in detail the diffusion during the two-dimensional condensation reaction as well as the asymmetric biaxial strain of the SiGe fin before and after oxidation using a reciprocal space mapping measurement. The application of dry oxidation on selectively grown SiGe fin layer can be an effective method for increasing hole mobility of SiGe fin with increased Ge content and self-induced compressive strain.

Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.

2000-01-01

NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station. The X-38 control surfaces require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. This paper presents results for thermal analyses and flow and compression tests conducted on as-received and thermally exposed seals for the rudder/fin location of the X-38. A thermal analysis of the rudder/fin dual seal assembly based on representative heating rates on the windward surface of the rudder/fin area predicted a peak seal temperature of 1900 F. The temperature-exposed seals were heated in a compressed state at 1900 F corresponding to the predicted peak temperature. Room temperature compression tests were performed to determine load versus linear compression, preload, contact area, stiffness, and resiliency characteristics for the as-received and temperature-exposed seals. Temperature exposure resulted in permanent set and loss of resiliency in these seals. Unit loads and contact pressures for the seals were below the 5 lb/in. and 10 psi limits set to limit the loads on the Shuttle thermal tiles that the seals seal against in the rudder/fin location. Measured seal flow rates for a double seal were about 4.5 times higher than the preliminary seal flow goal. The seal designs examined in this study are expected to be able to endure the high temperatures that they will be exposed to for a single-use life. Tests performed herein combined with future analyses, arc jet tests, and scrubbing tests will be used to select the final seal design for this application.

Rudder/Fin Seal Investigations for the X-38 Re-Entry Vehicle

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.

2000-01-01

NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a crew return vehicle (CRV) for the International Space Station. The X-38 control surfaces require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. This paper presents results for thermal analyses and flow and compression tests conducted on as-received and thermally exposed seals for the rudder/fin location of the X-38. A thermal analysis of the rudder/fin dual seal assembly based on representative heating rates on the windward surface of the rudder/fin area predicted a peak seal temperature of 1900 F. The temperature-exposed seals were heated in a compressed state at 1900 F corresponding to the predicted peak temperature. Room temperature compression tests were performed to determine load versus linear compression, preload, contact area, stiffness, and resiliency characteristics for the as-received and temperature-exposed seals. Temperature exposure resulted in permanent set and loss of resiliency in these seals. Unit loads and contact pressures for the seals were below the five pounds/inch and ten psi limits set to limit the loads on the Shuttle thermal tiles that the seals seal against in the rudder/fin location. Measured seal flow rates for a double seal were about 4.5 times higher than the preliminary seal flow goal. The seal designs examined in this study are expected to be able to endure the high temperatures that they will be exposed to for a single-use life. Tests performed herein combined with future analyses, arc jet tests, and scrubbing tests will be used to select the final seal design for this application.

Sin(x)**2 + cos(x)**2 = 1. [programming identities using comparative combinatorial substitutions

NASA Technical Reports Server (NTRS)

Stoutemyer, D. R.

1977-01-01

Attempts to achieve tasteful automatic employment of the identities sin sq x + cos sq x = 1 and cos sq h x -sin sq h x = 1 in a manner which truly minimizes the complexity of the resulting expression are described. The disappointments of trigonometric reduction, trigonometric expansion, pattern matching, Poisson series, and Demoivre's theorem are related. The advantages of using the method of comparative combinatorial substitutions are illustrated.

The effect of traveling wave shapes in the maneuver control and efficiency of an underwater robot propelled by an undulating fin

NASA Astrophysics Data System (ADS)

Liu, Hanlin; Curet, Oscar

2016-11-01

Effective control of propulsive undulating fins has the potential to enhance the maneuverability and efficiency of underwater vehicles allowing them to navigate in more complex environments. Aquatic animals using this type of propulsion are able to perform complex maneuvers by sending different traveling waves along one or multiple elongated fins. Recent work has investigated the propulsive forces, the hydrodynamics and the efficiency of an undulating ribbon fin. However, it is still not understood how different traveling wave shapes along the fin can be used to control the hydrodynamic forces and torques to perform different maneuvers. In this work, we study the effect of traveling wave shapes on the hydrodynamic forces and torques, swimming speed, maneuver control and propulsive performance of an underwater vehicle propelled by an undulating fin. The underwater robot propels by actuating a fin that is composed of sixteen independent rays interconnected with a flexible membrane. The hull contains all the electronics, batteries, motors and sensors. The underwater vehicle was tested in a water tank-flume facility. In a series of experiments, we measured the motion of the vessel and the power consumption for different traveling wave patterns. In addition, we measured the flow around the fin using Particle Image Velocimetry. We present the results concerning the power distribution along the fin, propulsive efficiency, free-swimming speed and pitch control based on different fin kinematics. National Science Foundation under Grant No. 1420774.

Computational Fluid Dynamics (CFD) Simulations of a Finned Projectile with Microflaps for Flow Control

DTIC Science & Technology

2016-04-01

fields associated with these control mechanisms for US Army weapons are complex, involving 3-dimensional (3-D) shock- boundary layer interactions...distribution over the rear finned section and thus produce control forces and moments. Dykes et al.6 used a flat - plate fin interaction design of...cells—tetrahedrals, triangular prisms, and pyramids—were used in the mesh. Grid points shown in Fig. 3a were clustered in the boundary layer region

On-line estimation and compensation of measurement delay in GPS/SINS integration

NASA Astrophysics Data System (ADS)

Yang, Tao; Wang, Wei

2008-10-01

The chief aim of this paper is to propose a simple on-line estimation and compensation method of GPS/SINS measurement delay. The causes of time delay for GPS/SINS integration are analyzed in this paper. New Kalman filter state equations augmented by measurement delay and modified measurement equations are derived. Based on an open-loop Kalman filter, several simulations are run, results of which show that by the proposed method, the estimation and compensation error of measurement delay is below 0.1s.

Analysis of Fin-Line at Millimeter Wavelengths.

DTIC Science & Technology

1982-07-01

8217.gation Constants, Field Calculation. 20, AaSTRAC ’Continue on reverse side If necessary and identify by bt~ck number; --- An analysis of fin-line is...presented along with numerical and experimental results. Dispersion characteristics and field distributions are given for a number of single-mode and...characteristics and field distri- butions are given for a number of single-mode and multi-mode configurations. Agreement between theory and experiment is shown

Expression of Hsp70 reveals significant differences between fin regeneration and inflammation in Paramisgurnus dabryanus.

PubMed

Li, Li; Wang, Linlin; He, Jingya; Chang, Zhongjie

2017-05-01

Hsp70 is the most strongly induced in response to various cellular stresses and a good candidate for investigating its role in tissue injury. We firstly cloned full-length cDNA of hsp70 from Paramisgurnus dabryanus (PdHsp70) by RACE method (GenBank: KP402408.1). Then regeneration and inflammation of fin were established by amputation and scratch respectively. Quantitative RT-PCR detected the PdHsp70 began to increase rapidly its expression at 1 days post amputation (dpa) and reached the peak at 2 dpa during fin regeneration. Its expression was also up-regulated at 2 days post scratch (dps) of inflammation but still significant weaker in comparison with it in regenerated fin at 2 dpa. Next, immunohistochemistry analysis of PdHsp70 showed that PdHsp70 located mainly in the deeper epidermis of regenerated fin and was stronger than its expression in the scratched inflammatory fin which was involved in whole epidermal. SDS-PAGE and Western blotting confirmed that the PdHsp70 protein expressed efficiently in Escherichia coli BL21. These findings have implied that PdHsp70 are implicated in different regulation of regeneration and inflammation in response to injury stimulation. During the regeneration, it is involved in the formation of wound epidermis by mediating cellular protection whereas it can modulate inflammatory by activating the innate immune response. Copyright © 2017. Published by Elsevier Ltd.

A Middle Triassic thoracopterid from China highlights the evolutionary origin of overwater gliding in early ray-finned fishes.

PubMed

Xu, Guang-Hui; Zhao, Li-Jun; Shen, Chen-Chen

2015-01-01

Gliding adaptations in thoracopterid flying fishes represent a remarkable case of convergent evolution of overwater gliding strategy with modern exocoetid flying fishes, but the evolutionary origin of this strategy was poorly known in the thoracopterids because of lack of transitional forms. Until recently, all thoracopterids, from the Late Triassic of Austria and Italy and the Middle Triassic of South China, were highly specialized 'four-winged' gliders in having wing-like paired fins and an asymmetrical caudal fin with the lower caudal lobe notably larger than the upper lobe. Here, we show that the new genus Wushaichthys and the previously alleged 'peltopleurid' Peripeltopleurus, from the Middle Triassic (Ladinian, 235-242 Ma) of South China and near the Ladinian/Anisian boundary of southern Switzerland and northern Italy, respectively, represent the most primitive and oldest known thoracopterids. Wushaichthys, the most basal thoracopterid, shows certain derived features of this group in the skull. Peripeltopleurus shows a condition intermediate between Wushaichthys and Thoracopterus in having a slightly asymmetrical caudal fin but still lacking wing-like paired fins. Phylogenetic studies suggest that the evolution of overwater gliding of thoracopterids was gradual in nature; a four-stage adaption following the 'cranial specialization-asymmetrical caudal fin-enlarged paired fins-scale reduction' sequence has been recognized in thoracopterid evolution. Moreover, Wushaichthys and Peripeltopleurus bear hooklets on the anal fin of supposed males, resembling those of modern viviparious teleosts. Early thoracopterids probably had evolved a live-bearing reproductive strategy. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Investigation of powder injection moulded oblique fin heat sinks

NASA Astrophysics Data System (ADS)

Sai, Vadri Siva

The present work attempts to study the fluid flow and heat transfer characteristics of PIM oblique finned microchannel heat sink both numerically and experimentally. Experimental results such as thermal resistance and pressure drop have been well validated with ANSYS FLUENT simulations. Hot spots are observed at the most downstream location of the channel is due to the effect of flow migration. Finally, a novel technique has been proposed to reduce the pressure drop on creating additional channels by removing some material at the middle portion of oblique fins. It is found that the creation of oblique cuts incurred a reduction in both pressure drop and Nuavg up to 31.36 % and 16.66 % respectively at a flow rate of 500 ml/min. Nevertheless, for all the flowrates considered in this analysis. % reduction in pressure drop is almost double as compared with % reduction in Nuavg. Therefore, this analysis is beneflcial in reducing the additional cost incurs due to pressure drop penalty.

Volumetric PIV of multiple free-swimming maneuvers generated by the KnifeBot: a biomimetic vessel propelled by an undulating fin

NASA Astrophysics Data System (ADS)

Liu, Hanlin; Troolin, Daniel; Hortensius, Ruben; Pothos, Stamatios; Curet, Oscar

2017-11-01

An undulating fin represents a remarkable propulsion model for underwater vehicles due to its high propulsive efficiency and considerable locomotor capabilities. In this work, we used a bio-inspired vessel, the KnifeBot to demonstrate the maneuverability of undulating fin propulsion, including forward-backward swimming, station keeping and vertical swimming. This self-contained robotic system uses an undulating ventral fin as the propulsor and features a slender 3D-printed hull with 16 motors, 2 batteries and electronic boards encapsulated inside. We tested the robot in a water-filled tank and used volumetric particle image velocimetry (V3V PIV) to investigate the three-dimensional flow features and vortex structures generated by the undulating ribbon fin in free-swimming maneuvers. Our results indicate that in the forward swimming, a series of vortex tubes are shed off the fin edge. A streamwise jet at an oblique angle to the fin is generated in association with the vortex tubes propelling the robot forward as well as pitching it up. For the hovering maneuver with inward counter-propagating waves. The streamlines develop vertically downward with the tip vortex shed from the fin edge. This downward jet provides substantial heave force for the robot to swim upward or perform station keeping. Our findings will be useful for understanding the mechanical basis of undulating fin propulsion and facilitate the development of bio-inspired vehicles using undulatory propellers. Office of Naval Research under Award Number N00014-16-1-2505.

Progress on the Use of Internal Fins as Barriers to Reduce Magnetization on High Current Density Mono Element Internal Tin Conductors (MEIT)

NASA Astrophysics Data System (ADS)

Zeitlin, Bruce A.; Gregory, Eric; Pyon, Taeyoung; Scanlan, R. M.; Polyanskii, Anatolii A.; Lee, Peter J.

2004-06-01

A number of configurations of a mono element internal tin conductor (MEIT) were fabricated to explore the effect of internal fins on the effective filament size (Deff) and its effect on wire processing. A current density of 2.85 × 109 A/m2 (12 T) was achieved in a high tin, high Nb conductor. Wire lengths as long as 15.8 km at 0.254 mm diameter with breaks averaging 3 per unit length were achieved. Magnetization measurements and Magneto-Optical (MO) images were taken of the finned and non-fin conductor which indicated the fins appeared to be effective. The Deff achieved in the fin conductor was 80 μm compared with an equivalent conductor without a fin of 165 μm.

A 3-D CFD Analysis of the Space Shuttle RSRM With Propellant Fins @ 1 sec. Burn-Back

NASA Technical Reports Server (NTRS)

Morstadt, Robert A.

2003-01-01

In this study 3-D Computational Fluid Dynamic (CFD) runs have been made for the Space Shuttle RSRM using 2 different grids and 4 different turbulent models, which were the Standard KE, the RNG KE, the Realizable KE, and the Reynolds stress model. The RSRM forward segment consists of 11 fins. By taking advantage of the forward fin symmetry only half of one fin along the axis had to be used in making the grid. This meant that the 3-D model consisted of a pie slice that encompassed 1/22nd of the motor circumference and went along the axis of the entire motor. The 3-D flow patterns in the forward fin region are of particular interest. Close inspection of these flow patterns indicate that 2 counter-rotating axial vortices emerge from each submerged solid propellant fin. Thus, the 3-D CFD analysis allows insight into complicated internal motor flow patterns that are not available from the simpler 2-D axi-symmetric studies. In addition, a comparison is made between the 3-D bore pressure drop and the 2-D axi-symmetric pressure drop.

Hydrodynamic thrust generation and power consumption investigations for piezoelectric fins with different aspect ratios

NASA Astrophysics Data System (ADS)

Shahab, S.; Tan, D.; Erturk, A.

2015-12-01

Bio-inspired hydrodynamic thrust generation using piezoelectric transduction has recently been explored using Macro-Fiber Composite (MFC) actuators. The MFC technology strikes a balance between the actuation force and structural deformation levels for effective swimming performance, and additionally offers geometric scalability, silent operation, and ease of fabrication. Recently we have shown that mean thrust levels comparable to biological fish of similar size can be achieved using MFC fins. The present work investigates the effect of length-to-width (L/b) aspect ratio on the hydrodynamic thrust generation performance of MFC cantilever fins by accounting for the power consumption level. It is known that the hydrodynamic inertia and drag coefficients are controlled by the aspect ratio especially for L/b< 5. The three MFC bimorph fins explored in this work have the aspect ratios of 2.1, 3.9, and 5.4. A nonlinear electrohydroelastic model is employed to extract the inertia and drag coefficients from the vibration response to harmonic actuation for the first bending mode. Experiments are then conducted for various actuation voltage levels to quantify the mean thrust resultant and power consumption levels for different aspect ratios. Variation of the thrust coefficient of the MFC bimorph fins with changing aspect ratio is also semi-empirically modeled and presented.

A Feasibility Analysis of Land-Based SINS/GNSS Gravimetry for Groundwater Resource Detection in Taiwan

PubMed Central

Chiang, Kai-Wei; Lin, Cheng-An; Kuo, Chung-Yen

2015-01-01

The integration of the Strapdown Inertial Navigation System and Global Navigation Satellite System (SINS/GNSS) has been implemented for land-based gravimetry and has been proven to perform well in estimating gravity. Based on the mGal-level gravimetry results, this research aims to construct and develop a land-based SINS/GNSS gravimetry device containing a navigation-grade Inertial Measurement Unit. This research also presents a feasibility analysis for groundwater resource detection. A preliminary comparison of the kinematic velocities and accelerations using multi-combination of GNSS data including Global Positioning System, Global Navigation Satellite System, and BeiDou Navigation Satellite System, indicates that three-system observations performed better than two-system data in the computation. A comparison of gravity derived from SINS/GNSS and measured using a relative gravimeter also shows that both agree reasonably well with a mean difference of 2.30 mGal. The mean difference between repeat measurements of gravity disturbance using SINS/GNSS is 2.46 mGal with a standard deviation of 1.32 mGal. The gravity variation because of the groundwater at Pingtung Plain, Taiwan could reach 2.72 mGal. Hence, the developed land-based SINS/GNSS gravimetry can sufficiently and effectively detect groundwater resources. PMID:26426019

A Feasibility Analysis of Land-Based SINS/GNSS Gravimetry for Groundwater Resource Detection in Taiwan.

PubMed

Chiang, Kai-Wei; Lin, Cheng-An; Kuo, Chung-Yen

2015-09-29

The integration of the Strapdown Inertial Navigation System and Global Navigation Satellite System (SINS/GNSS) has been implemented for land-based gravimetry and has been proven to perform well in estimating gravity. Based on the mGal-level gravimetry results, this research aims to construct and develop a land-based SINS/GNSS gravimetry device containing a navigation-grade Inertial Measurement Unit. This research also presents a feasibility analysis for groundwater resource detection. A preliminary comparison of the kinematic velocities and accelerations using multi-combination of GNSS data including Global Positioning System, Global Navigation Satellite System, and BeiDou Navigation Satellite System, indicates that three-system observations performed better than two-system data in the computation. A comparison of gravity derived from SINS/GNSS and measured using a relative gravimeter also shows that both agree reasonably well with a mean difference of 2.30 mGal. The mean difference between repeat measurements of gravity disturbance using SINS/GNSS is 2.46 mGal with a standard deviation of 1.32 mGal. The gravity variation because of the groundwater at Pingtung Plain, Taiwan could reach 2.72 mGal. Hence, the developed land-based SINS/GNSS gravimetry can sufficiently and effectively detect groundwater resources.

Heat Transfer of HC290-OIL Mixtures in a Horizontal Condensing Micro-Fin Tube

NASA Astrophysics Data System (ADS)

Tong, M. W.; Dong, M. L.; Li, Y.

Heat transfer coefficients was experimentally determined for a horizontal micro-fin tube (2m in length, 11.44mm ID) with HC290-oil mixtures. The oil is Suniso 3GS, which is a widely used oil in refrigerant systems. The micro-fin tube is a internally enhanced tube, which has 60 fins with a height of 0.25mm and 20° spiral angle. The condensation temperatures varied from 40° to 45° and the refrigerant mass flux was varied from 40kg/(m2s) to 220kg/(m2s). The results showed that the mean condensation heat transfer coefficients on the test section (inlet vapor quality 1, outlet vapor quality 0.1~0.25) decreased as the oil concentrations were increased and the condensation temperature had negligible effect on the heat transfer coefficients.

DNA barcodes of the native ray-finned fishes in Taiwan.

PubMed

Chang, Chia-Hao; Shao, Kwang-Tsao; Lin, Han-Yang; Chiu, Yung-Chieh; Lee, Mao-Ying; Liu, Shih-Hui; Lin, Pai-Lei

2017-07-01

Species identification based on the DNA sequence of a fragment of the cytochrome c oxidase subunit I gene in the mitochondrial genome, DNA barcoding, is widely applied to assist in sustainable exploitation of fish resources and the protection of fish biodiversity. The aim of this study was to establish a reliable barcoding reference database of the native ray-finned fishes in Taiwan. A total of 2993 individuals, belonging to 1245 species within 637 genera, 184 families and 29 orders of ray-finned fishes and representing approximately 40% of the recorded ray-finned fishes in Taiwan, were PCR amplified at the barcode region and bidirectionally sequenced. The mean length of the 2993 barcodes is 549 bp. Mean congeneric K2P distance (15.24%) is approximately 10-fold higher than the mean conspecific one (1.51%), but approximately 1.4-fold less than the mean genetic distance between families (20.80%). The Barcode Index Number (BIN) discordance report shows that 2993 specimens represent 1275 BINs and, among them, 86 BINs are singletons, 570 BINs are taxonomically concordant, and the other 619 BINs are taxonomically discordant. Barcode gap analysis also revealed that more than 90% of the collected fishes in this study can be discriminated by DNA barcoding. Overall, the barcoding reference database established by this study reveals the need for taxonomic revisions and voucher specimen rechecks, in addition to assisting in the management of Taiwan's fish resources and diversity. © 2016 John Wiley & Sons Ltd.

[Control levels of Sin3 histone deacetylase for spontaneous and UV-induced mutagenesis in yeasts Saccharomyces cerevisiae].

PubMed

Lebovka, I Iu; Kozhina, T N; Fedorova, I V; Peshekhonov, V T; Evstiukhina, T A; Chernenkov, A Iu; Korolev, V G

2014-01-01

SIN3 gene product operates as a repressor for a huge amount of genes in Saccharomyces cerevisiae. Sin3 protein with a mass of about 175 kDa is a member of the RPD3 protein complex with an assessed mass of greater than 2 million Da. It was previously shownthat RPD3 gene mutations influence recombination and repair processes in S. cerevisiae yeasts. We studied the impacts of the sin3 mutation on UV-light sensitivity and UV-induced mutagenesis in budding yeast cells. The deletion ofthe SIN3 gene causes weak UV-sensitivity of mutant budding cells as compared to the wild-type strain. These results show that the sin3 mutation decreases both spontaneous and UV-induced levels of levels. This fact is hypothetically related to themalfunction of ribonucleotide reductase activity regulation, which leads to a decrease in the dNTP pool and the inaccurate error-prone damage bypass postreplication repair pathway, which in turn provokes a reduction in the incidence of mutations.

Esco2 regulates cx43 expression during skeletal regeneration in the zebrafish fin.

PubMed

Banerji, Rajeswari; Eble, Diane M; Iovine, M Kathryn; Skibbens, Robert V

2016-01-01

Roberts syndrome (RBS) is a rare genetic disorder characterized by craniofacial abnormalities, limb malformation, and often severe mental retardation. RBS arises from mutations in ESCO2 that encodes an acetyltransferase and modifies the cohesin subunit SMC3. Mutations in SCC2/NIPBL (encodes a cohesin loader), SMC3 or other cohesin genes (SMC1, RAD21/MCD1) give rise to a related developmental malady termed Cornelia de Lange syndrome (CdLS). RBS and CdLS exhibit overlapping phenotypes, but RBS is thought to arise through mitotic failure and limited progenitor cell proliferation while CdLS arises through transcriptional dysregulation. Here, we use the zebrafish regenerating fin model to test the mechanism through which RBS-type phenotypes arise. esco2 is up-regulated during fin regeneration and specifically within the blastema. esco2 knockdown adversely affects both tissue and bone growth in regenerating fins-consistent with a role in skeletal morphogenesis. esco2-knockdown significantly diminishes cx43/gja1 expression which encodes the gap junction connexin subunit required for cell-cell communication. cx43 mutations cause the short fin (sof(b123) ) phenotype in zebrafish and oculodentodigital dysplasia (ODDD) in humans. Importantly, miR-133-dependent cx43 overexpression rescues esco2-dependent growth defects. These results conceptually link ODDD to cohesinopathies and provide evidence that ESCO2 may play a transcriptional role critical for human development. © 2015 Wiley Periodicals, Inc.

Performance analysis and optimization of radiating fins with a step change in thickness and variable thermal conductivity by homotopy perturbation method

NASA Astrophysics Data System (ADS)

Arslanturk, Cihat

2011-02-01

Although tapered fins transfer more rate of heat per unit volume, they are not found in every practical application because of the difficulty in manufacturing and fabrications. Therefore, there is a scope to modify the geometry of a constant thickness fin in view of the less difficulty in manufacturing and fabrication as well as betterment of heat transfer rate per unit volume of the fin material. For the better utilization of fin material, it is proposed a modified geometry of new fin with a step change in thickness (SF) in the literature. In the present paper, the homotopy perturbation method has been used to evaluate the temperature distribution within the straight radiating fins with a step change in thickness and variable thermal conductivity. The temperature profile has an abrupt change in the temperature gradient where the step change in thickness occurs and thermal conductivity parameter describing the variation of thermal conductivity has an important role on the temperature profile and the heat transfer rate. The optimum geometry which maximizes the heat transfer rate for a given fin volume has been found. The derived condition of optimality gives an open choice to the designer.

El medio interestelar alrededor de estrellas Of

NASA Astrophysics Data System (ADS)

Caballero, N.; Cappa, C.

Se analiza la distribución del hidrógeno neutro interestelar en la vecindad de algunas estrellas Of con el fin de investigar la presencia de burbujas de H I vinculadas a las estrellas. Se determinan los parámetros físicos de las burbujas de H I encontradas y se comparan con estructuras similares vinculadas a estrellas Wolf-Rayet. El estudio se lleva a cabo en base a datos pertenecientes al relevamiento de Weaver y Willians (1973).

Fluid flow and heat transfer characteristics of an enclosure with fin as a top cover of a solar collector

NASA Astrophysics Data System (ADS)

Ambarita, H.; Ronowikarto, A. D.; Siregar, R. E. T.; Setyawan, E. Y.

2018-03-01

To reduce heat loses in a flat plate solar collector, double glasses cover is employed. Several studies show that the heat loss from the glass cover is still very significant in comparison with other losses. Here, double glasses cover with attached fins is proposed. In the present work, the fluid flow and heat transfer characteristics of the enclosure between the double glass cover are investigated numerically. The objective is to examine the effect of the fin to the heat transfer rate of the cover. Two-dimensional governing equations are developed. The governing equations and the boundary conditions are solved using commercial Computational Fluid Dynamics code. The fluid flow and heat transfer characteristics are plotted, and numerical results are compared with empirical correlation. The results show that the presence of the fin strongly affects the fluid flow and heat transfer characteristics. The fin can reduce the heat transfer rate up to 22.42% in comparison with double glasses cover without fins.

Effectiveness of fins formed by dimples in the form of ball segments

NASA Astrophysics Data System (ADS)

Gabdrakhmanov, E. A.; Afonin, G. N.; Glazov, V. S.

2017-11-01

One of the famous ways to improve efficiency of a heat exchanger is associated with the topography of the surfaces being in contact with coolants. So, use of hemispherical dimples leads to progressive growth of the relative heat transfer coefficient compared to increase of the relative resistance coefficient. Usually a plate having the spherical dimple intensifiers for heat transfer is considered as a flat one with embedded cavities. However, such a plate can be also considered as the plate with inbuilt fins which are formed by dimples in the form of ball segments. Given that for the flow of fluid (gas) from left to right, the minimum local heat transfer enhancement occurs in the first (left) half of the dimples, and the maximum falls on the edge of the second (right) half, we obtained an analytical solution describing the temperature distribution along the height of the fin. In the solution we used the Harper-Brown approach. Presented are the results of the calculation of the efficiency of the surface on the parameters of the considered fin and on a known value of the average heat transfer coefficient corresponding to the stage of the fluid flow steady state.

Tracking fin whale calls offshore the Galicia Margin, North East Atlantic Ocean.

PubMed

Gaspà Rebull, Oriol; Díaz Cusí, Jordi; Ruiz Fernández, Mario; Gallart Muset, Josep

2006-10-01

Data recorded during a temporary deployment of ocean bottom seismometers (OBSs) are used in this study to monitor the presence of fin whales around the array. In the summer of 2003, ten OBSs were placed 250 km from the NW coast of Iberia in the Galicia Margin, NE Atlantic Ocean for a period of one month. The recorded data set provided a large variety of signals, including fin whale vocalizations identified by their specific acoustic signature. The use of a dense array of seafloor receivers allowed investigation into the locations and tracks of the signal-generating whales using a seismological hypocentral location code. Individual pulses of different sequences have been chosen to study such tracks. Problems related to the correct identification of pulses, discrimination between direct and multiple arrivals, and the presence of more than one individual have been considered prior to location. Fin calls were concentrated in the last two weeks of the deployment and the locations were spread around the area covered by the array. These results illustrate that, besides its classical seismological aim, deployment of semipermanent seafloor seismic arrays can also provide valuable data for marine mammal behavior studies.

Post Irradiation Examination Results of the NT-02 Graphite Fins NUMI Target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ammigan, K.; Hurh, P.; Sidorov, V.

2017-02-10

The NT-02 neutrino target in the NuMI beamline at Fermilab is a 95 cm long target made up of segmented graphite fins. It is the longest running NuMI target, which operated with a 120 GeV proton beam with maximum power of 340 kW, and saw an integrated total proton on target of 6.1 1020. Over the last half of its life, gradual degradation of neutrino yield was observed until the target was replaced. The probable causes for the target performance degradation are attributed to radiation damage, possibly including cracking caused by reduction in thermal shock resistance, as well as potentialmore » localized oxidation in the heated region of the target. Understanding the long-termstructural response of target materials exposed to proton irradiation is critical as future proton accelerator sources are becoming increasingly more powerful. As a result, an autopsy of the target was carried out to facilitate post-irradiation examination of selected graphite fins. Advanced microstructural imaging and surface elemental analysis techniques were used to characterize the condition of the fins in an effort to identify degradation mechanisms, and the relevant findings are presented in this paper.« less

Population trends in Pacific Oceanic sharks and the utility of regulations on shark finning.

PubMed

Clarke, Shelley C; Harley, Shelton J; Hoyle, Simon D; Rice, Joel S

2013-02-01

Accurate assessment of shark population status is essential for conservation but is often constrained by limited and unreliable data. To provide a basis for improved management of shark resources, we analyzed a long-term record of species-specific catches, sizes, and sexes of sharks collected by onboard observers in the western and central Pacific Ocean from 1995 to 2010. Using generalized linear models, we estimated population-status indicators on the basis of catch rate and biological indicators of fishing pressure on the basis of median size to identify trends for blue (Prionace glauca), mako (Isurus spp.), oceanic whitetip (Carcharhinus longimanus), and silky (Carcharhinus falciformis) sharks. Standardized catch rates of longline fleets declined significantly for blue sharks in the North Pacific (by 5% per year [CI 2% to 8%]), for mako sharks in the North Pacific (by 7% per year [CI 3% to 11%]), and for oceanic whitetip sharks in tropical waters (by 17% per year [CI 14% to 20%]). Median lengths of silky and oceanic whitetip sharks decreased significantly in their core habitat, and almost all sampled silky sharks were immature. Our results are consistent with results of analyses of similar data sets. Combined, these results and evidence of targeted fishing for sharks in some regional fisheries heighten concerns for sustainable utilization, particularly for oceanic whitetip and North Pacific blue sharks. Regional regulations that prohibit shark finning (removal of fins and discarding of the carcass) were enacted in 2007 and are in many cases the only form of control on shark catches. However, there is little evidence of a reduction of finning in longline fisheries. In addition, silky and oceanic whitetip sharks are more frequently retained than finned, which suggests that even full implementation of and adherence to a finning prohibition may not substantially reduce mortality rates for these species. We argue that finning prohibitions divert attention from

FinFET-based Miller encoder for UHF and SHF RFID application

NASA Astrophysics Data System (ADS)

Srinivasulu, Avireni; Sravanthi, G.; Sarada, M.; Pal, Dipankar

2018-01-01

This paper proposes a T-flip-flop and a Miller encoder design for ultra-high frequency and super high frequency, radio-frequency identification (RFID) application using FinFETs. Miller encoder is used in magnetic recording, in optical domain and also in RFID. Performance of the proposed circuit was examined by installing the model parameters of 20-nm FinFET (obtained from open source) on Cadence platform with +0.4 V supply rail at frequencies of 1, 2 and 10 GHz. Simulation results have confirmed that proposed Miller encoder offers a simpler design with reduced transistor count and gives lower power dissipation, higher frequency range of operation at lower supply rail as compared to other candidate designs. Proposed design also promises less propagation delay.

Reconsideration of data and correlations for plate finned-tube heat exchangers

NASA Astrophysics Data System (ADS)

Otović, Milena; Mihailović, Miloš; Genić, Srbislav; Jaćimović, Branislav; Milovančević, Uroš; Marković, Saša

2018-04-01

This paper deals with heat exchangers having plain finned tubes in staggered (triangular) pattern. The objective of this paper is to provide the heat transfer and friction factor correlation which can be used in engineering practice. For this purpose, the experimental data of several (most cited) authors who deal with this type of heat exchangers are used. The new correlations are established to predict the air-side heat transfer coefficient and friction factor as a function of the Reynolds number and geometric variables of the heat exchanger - tube diameter, tube pitch, fin spacing, tube rows, etc. In those correlations the characteristic dimension in Reynolds number is calculated by using the new parameter - volumetric porosity. Also, there are given the errors of those correlations.

Dual Regulation of Bacillus subtilis kinB Gene Encoding a Sporulation Trigger by SinR through Transcription Repression and Positive Stringent Transcription Control.

PubMed

Fujita, Yasutaro; Ogura, Mitsuo; Nii, Satomi; Hirooka, Kazutake

2017-01-01

It is known that transcription of kinB encoding a trigger for Bacillus subtilis sporulation is under repression by SinR, a master repressor of biofilm formation, and under positive stringent transcription control depending on the adenine species at the transcription initiation nucleotide (nt). Deletion and base substitution analyses of the kinB promoter (P kinB ) region using lacZ fusions indicated that either a 5-nt deletion (Δ5, nt -61/-57, +1 is the transcription initiation nt) or the substitution of G at nt -45 with A (G-45A) relieved kinB repression. Thus, we found a pair of SinR-binding consensus sequences (GTTCTYT; Y is T or C) in an inverted orientation (SinR-1) between nt -57/-42, which is most likely a SinR-binding site for kinB repression. This relief from SinR repression likely requires SinI, an antagonist of SinR. Surprisingly, we found that SinR is essential for positive stringent transcription control of P kinB . Electrophoretic mobility shift assay (EMSA) analysis indicated that SinR bound not only to SinR-1 but also to SinR-2 (nt -29/-8) consisting of another pair of SinR consensus sequences in a tandem repeat arrangement; the two sequences partially overlap the '-35' and '-10' regions of P kinB . Introduction of base substitutions (T-27C C-26T) in the upstream consensus sequence of SinR-2 affected positive stringent transcription control of P kinB , suggesting that SinR binding to SinR-2 likely causes this positive control. EMSA also implied that RNA polymerase and SinR are possibly bound together to SinR-2 to form a transcription initiation complex for kinB transcription. Thus, it was suggested in this work that derepression of kinB from SinR repression by SinI induced by Spo0A∼P and occurrence of SinR-dependent positive stringent transcription control of kinB might induce effective sporulation cooperatively, implying an intimate interplay by stringent response, sporulation, and biofilm formation.

The dlx5a/dlx6a Genes Play Essential Roles in the Early Development of Zebrafish Median Fin and Pectoral Structures

PubMed Central

Heude, Églantine; Shaikho, Sarah; Ekker, Marc

2014-01-01

The Dlx5 and Dlx6 genes encode homeodomain transcription factors essential for the proper development of limbs in mammalian species. However, the role of their teleost counterparts in fin development has received little attention. Here, we show that dlx5a is an early marker of apical ectodermal cells of the pectoral fin buds and of the median fin fold, but also of cleithrum precursor cells during pectoral girdle development. We propose that early median fin fold establishment results from the medial convergence of dlx5a-expressing cells at the lateral edges of the neural keel. Expression analysis also shows involvement of dlx5a during appendage skeletogenesis. Using morpholino-mediated knock down, we demonstrate that disrupted dlx5a/6a function results in pectoral fin agenesis associated with misexpression of bmp4, fgf8a, and1 and msx genes. In contrast, the median fin fold presents defects in mesenchymal cell migration and actinotrichia formation, whereas the initial specification seems to occur normally. Our results demonstrate that the dlx5a/6a genes are essential for the induction of pectoral fin outgrowth, but are not required during median fin fold specification. The dlx5a/6a knock down also causes a failure of cleithrum formation associated with a drastic loss of runx2b and col10a1 expression. The data indicate distinct requirements for dlx5a/6a during median and pectoral fin development suggesting that initiation of unpaired and paired fin formation are not directed through the same molecular mechanisms. Our results refocus arguments on the mechanistic basis of paired appendage genesis during vertebrate evolution. PMID:24858471

Functional properties of protein from frozen mantle and fin of jumbo squid Dosidicus gigas in function of pH and ionic strength.

PubMed

Rocha-Estrada, J G; Córdova-Murueta, J H; García-Carreño, F L

2010-10-01

Functional properties of protein from mantle and fin of the jumbo squid Dosidicus gigas were explained based on microscopic muscle fiber and protein fractions profiles as observed in SDS-PAGE. Fin has higher content of connective tissue and complex fiber arrangement, and we observed higher hardness of fin gels as expected. Myosin heavy chain (MHC) was found in sarcoplasmic, myofibril and soluble-in-alkali fractions of mantle and only in sarcoplasmic and soluble-in-alkali fractions of fin. An additive effect of salt concentration and pH affected the solubility and foaming properties. Fin and mantle proteins yielded similar results in solubility tests, but significant differences occurred for specific pH and concentrations of salt. Foaming capacity was proportional to solubility; foam stability was also affected by pH and salt concentration. Hardness and fracture strength of fin gels were significantly higher than mantle gels; gels from proteins of both tissues reached the highest level in the folding test. Structural and molecular properties, such as MHC and paramyosin solubility, arrangement of muscle fibers and the content of connective tissue were useful to explain the differences observed in these protein properties. High-strength gels can be formed from squid mantle or fin muscle. Fin displayed similar or better properties than mantle in all tests.

"... As we forgive those who trespass against us...": theological reflections on sin and guilt in the hospital environment.

PubMed

Schmidt, Kurt W

2005-08-01

In general parlance the term sin has lost its existential meaning. Originally a Jewish-Christian term within a purely religious context, referring to a wrongdoing with regard to God, sin has slowly become reduced to guilt in the course of the secularization process. Guilt refers to a wrongdoing, especially with regard to fellow human beings. It also refers to errors of judgement with what can be tragic consequences. These errors can occur whenever human beings are called upon to act, including the hospital environment. A Christian hospital has to address the issue of how to deal not only with guilt-ridden misdemeanors, but also with wrongdoing unto God, which overshadows every instance of guilt-ridden human behavior. Here, as in every parish, the Church Service is the place to acknowledge sin, confess sin, and forgive sin, beyond the boundaries of the parish itself.

Computational Study of Inbore and Inflight Heating for the 105MM, M774 Projectile Modified Swept Fin.

DTIC Science & Technology

1984-08-01

local 1* H. A. Dwyjer, R. J. K~ee, and B. R., Sanderse, "Adaptive Gr’id Method for’ ProbZe s in Ftuid Mechanie and Heat Transfer," 44.AL...A a.4 VoZ . 18...within the fin, heat conduction at the fin root into the pro- jectile body , and surface heat transfer at the fin tip. Other limitations in the heat...Figures 17a,b and 18a,b. From these figures the effect appears to be localized in the trailing edge region and no influence at the critical area near

Transformation of a metaphor: semantic shift in a Cantonese term 'Chi Sin' denoting insanity.

PubMed

Ng, J Y W; Chen, E Y H

2015-03-01

The historical evolution of the existing terms used to describe insanity may be able to shed light on the formation of stigma towards psychosis patients. In Hong Kong, a widely used Cantonese term for insanity 'Chi Sin' provides a unique example because of its neutral original sense, as it literally means misconnection in a network circuit. We attempt to trace the origin and subsequent evolution of the term 'Chi Sin' from its early use to the present day to understand how local Hong Kong people have attached increasingly negative connotations to this scientific term since the mid-20th century. We sampled as many newspapers and magazines published in Hong Kong from 1939 to June 2014 as possible, and sampled 7 popular local movies from the 1950s and 1960s. We also searched all the newspapers published in Hong Kong, Macau, Taiwan, and Mainland China from January 1998 to June 2014, and searched several other local historical resources. In one early use of 'Chi Sin' in 1939, the term was only used in a technical sense to describe 'short circuiting'. We found that the development of the telephone system, the Strowger system, in Hong Kong is closely related to the evolution of the semantics of the term 'Chi Sin'. The original meaning of short circuitry of the term 'Chi Sin' is no longer used, and it has become a dead metaphor through repeated use with negative emotional connotations. This illustrates some of the factors facilitating the emergence of a metaphor with subsequent semantic drift.

Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/sin I for a Large Sample of Late-K and M Dwarfs

NASA Astrophysics Data System (ADS)

Houdebine, E. R.; Mullan, D. J.; Paletou, F.; Gebran, M.

2016-05-01

The reliable determination of rotation-activity correlations (RACs) depends on precise measurements of the following stellar parameters: T eff, parallax, radius, metallicity, and rotational speed v sin I. In this paper, our goal is to focus on the determination of these parameters for a sample of K and M dwarfs. In a future paper (Paper II), we will combine our rotational data with activity data in order to construct RACs. Here, we report on a determination of effective temperatures based on the (R-I) C color from the calibrations of Mann et al. and Kenyon & Hartmann for four samples of late-K, dM2, dM3, and dM4 stars. We also determine stellar parameters (T eff, log(g), and [M/H]) using the principal component analysis-based inversion technique for a sample of 105 late-K dwarfs. We compile all effective temperatures from the literature for this sample. We determine empirical radius-[M/H] correlations in our stellar samples. This allows us to propose new effective temperatures, stellar radii, and metallicities for a large sample of 612 late-K and M dwarfs. Our mean radii agree well with those of Boyajian et al. We analyze HARPS and SOPHIE spectra of 105 late-K dwarfs, and we have detected v sin I in 92 stars. In combination with our previous v sin I measurements in M and K dwarfs, we now derive P/sin I measures for a sample of 418 K and M dwarfs. We investigate the distributions of P/sin I, and we show that they are different from one spectral subtype to another at a 99.9% confidence level. Based on observations available at Observatoire de Haute Provence and the European Southern Observatory databases and on Hipparcos parallax measurements.

ROTATION–ACTIVITY CORRELATIONS IN K AND M DWARFS. I. STELLAR PARAMETERS AND COMPILATIONS OF v sin i AND P /sin i FOR A LARGE SAMPLE OF LATE-K AND M DWARFS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houdebine, E. R.; Mullan, D. J.; Paletou, F.

The reliable determination of rotation–activity correlations (RACs) depends on precise measurements of the following stellar parameters: T {sub eff}, parallax, radius, metallicity, and rotational speed v sin i . In this paper, our goal is to focus on the determination of these parameters for a sample of K and M dwarfs. In a future paper (Paper II), we will combine our rotational data with activity data in order to construct RACs. Here, we report on a determination of effective temperatures based on the ( R – I ){sub C} color from the calibrations of Mann et al. and Kenyon andmore » Hartmann for four samples of late-K, dM2, dM3, and dM4 stars. We also determine stellar parameters ( T {sub eff}, log( g ), and [M/H]) using the principal component analysis–based inversion technique for a sample of 105 late-K dwarfs. We compile all effective temperatures from the literature for this sample. We determine empirical radius–[M/H] correlations in our stellar samples. This allows us to propose new effective temperatures, stellar radii, and metallicities for a large sample of 612 late-K and M dwarfs. Our mean radii agree well with those of Boyajian et al. We analyze HARPS and SOPHIE spectra of 105 late-K dwarfs, and we have detected v sin i in 92 stars. In combination with our previous v sin i measurements in M and K dwarfs, we now derive P /sin i measures for a sample of 418 K and M dwarfs. We investigate the distributions of P /sin i , and we show that they are different from one spectral subtype to another at a 99.9% confidence level.« less

Scale-dependent habitat use by a large free-ranging predator, the Mediterranean fin whale

NASA Astrophysics Data System (ADS)

Cotté, Cédric; Guinet, Christophe; Taupier-Letage, Isabelle; Mate, Bruce; Petiau, Estelle

2009-05-01

Since the heterogeneity of oceanographic conditions drives abundance, distribution, and availability of prey, it is essential to understand how foraging predators interact with their dynamic environment at various spatial and temporal scales. We examined the spatio-temporal relationships between oceanographic features and abundance of fin whales ( Balaenoptera physalus), the largest free-ranging predator in the Western Mediterranean Sea (WM), through two independent approaches. First, spatial modeling was used to estimate whale density, using waiting distance (the distance between detections) for fin whales along ferry routes across the WM, in relation to remotely sensed oceanographic parameters. At a large scale (basin and year), fin whales exhibited fidelity to the northern WM with a summer-aggregated and winter-dispersed pattern. At mesoscale (20-100 km), whales were found in colder, saltier (from an on-board system) and dynamic areas defined by steep altimetric and temperature gradients. Second, using an independent fin whale satellite tracking dataset, we showed that tracked whales were effectively preferentially located in favorable habitats, i.e. in areas of high predicted densities as identified by our previous model using oceanographic data contemporaneous to the tracking period. We suggest that the large-scale fidelity corresponds to temporally and spatially predictable habitat of whale favorite prey, the northern krill ( Meganyctiphanes norvegica), while mesoscale relationships are likely to identify areas of high prey concentration and availability.

Heat transfer and pressure drop in rectangular channels with crossing fins (a Review)

NASA Astrophysics Data System (ADS)

Sokolov, N. P.; Polishchuk, V. G.; Andreev, K. D.; Rassokhin, V. A.; Zabelin, N. A.

2015-06-01

Channels with crossing finning find wide use in the cooling paths of high-temperature gas turbine blade systems. At different times, different institutions carried out experimental investigations of heat transfer and pressure drop in channels with coplanar finning of opposite walls for obtaining semiempirical dependences of Nusselt criteria (dimensionless heat-transfer coefficients) and pressure drop coefficients on the operating Reynolds number and relative geometrical parameters (or their complexes). The shape of experimental channels, the conditions of experiments, and the used variables were selected so that they would be most suited for solving particular practical tasks. Therefore, the results obtained in processing the experimental data have large scatter and limited use. This article considers the results from experimental investigations of different authors. In comparing the results, additional calculations were carried out for bringing the mathematical correlations to the form of dependences from the same variables. Generalization of the results is carried out. In the final analysis, universal correlations are obtained for determining the pressure drop coefficients and Nusselt number values for the flow of working medium in channels with coplanar finning.

76 FR 19473 - Chrysler Financial Services Americas, LLC, a Subsidiary of FinCo Intermediate Holding Co., LLC...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-07

... Services Americas, LLC, a Subsidiary of FinCo Intermediate Holding Co., LLC, Troy Customer Contact Center... Co., LLC, Troy Customer Contact Center, Troy, Michigan (subject firm). The Department's Notice was... Services Americas, LLC, a subsidiary of FinCo Intermediate Holding Co., LLC, Troy Customer Contact Center...

A SINS/SRS/GNS Autonomous Integrated Navigation System Based on Spectral Redshift Velocity Measurements.

PubMed

Wei, Wenhui; Gao, Zhaohui; Gao, Shesheng; Jia, Ke

2018-04-09

In order to meet the requirements of autonomy and reliability for the navigation system, combined with the method of measuring speed by using the spectral redshift information of the natural celestial bodies, a new scheme, consisting of Strapdown Inertial Navigation System (SINS)/Spectral Redshift (SRS)/Geomagnetic Navigation System (GNS), is designed for autonomous integrated navigation systems. The principle of this SINS/SRS/GNS autonomous integrated navigation system is explored, and the corresponding mathematical model is established. Furthermore, a robust adaptive central difference particle filtering algorithm is proposed for this autonomous integrated navigation system. The simulation experiments are conducted and the results show that the designed SINS/SRS/GNS autonomous integrated navigation system possesses good autonomy, strong robustness and high reliability, thus providing a new solution for autonomous navigation technology.

A SINS/SRS/GNS Autonomous Integrated Navigation System Based on Spectral Redshift Velocity Measurements

PubMed Central

Wei, Wenhui; Gao, Zhaohui; Gao, Shesheng; Jia, Ke

2018-01-01

In order to meet the requirements of autonomy and reliability for the navigation system, combined with the method of measuring speed by using the spectral redshift information of the natural celestial bodies, a new scheme, consisting of Strapdown Inertial Navigation System (SINS)/Spectral Redshift (SRS)/Geomagnetic Navigation System (GNS), is designed for autonomous integrated navigation systems. The principle of this SINS/SRS/GNS autonomous integrated navigation system is explored, and the corresponding mathematical model is established. Furthermore, a robust adaptive central difference particle filtering algorithm is proposed for this autonomous integrated navigation system. The simulation experiments are conducted and the results show that the designed SINS/SRS/GNS autonomous integrated navigation system possesses good autonomy, strong robustness and high reliability, thus providing a new solution for autonomous navigation technology. PMID:29642549

Finned Carbon-Carbon Heat Pipe with Potassium Working Fluid

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.

2010-01-01

This elemental space radiator heat pipe is designed to operate in the 700 to 875 K temperature range. It consists of a C-C (carbon-carbon) shell made from poly-acrylonitride fibers that are woven in an angle interlock pattern and densified with pitch at high process temperature with integrally woven fins. The fins are 2.5 cm long and 1 mm thick, and provide an extended radiating surface at the colder condenser section of the heat pipe. The weave pattern features a continuous fiber bath from the inner tube surface to the outside edges of the fins to maximize the thermal conductance, and to thus minimize the temperature drop at the condenser end. The heat pipe and radiator element together are less than one-third the mass of conventional heat pipes of the same heat rejection surface area. To prevent the molten potassium working fluid from eroding the C C heat pipe wall, the shell is lined with a thin-walled, metallic tube liner (Nb-1 wt.% Zr), which is an integral part of a hermetic metal subassembly which is furnace-brazed to the inner surface of the C-C tube. The hermetic metal liner subassembly includes end caps and fill tubes fabricated from the same Nb-1Zr alloy. A combination of laser and electron beam methods is used to weld the end caps and fill tubes. A tungsten/inert gas weld seals the fill tubes after cleaning and charging the heat pipes with potassium. The external section of this liner, which was formed by a "Uniscan" rolling process, transitions to a larger wall thickness. This section, which protrudes beyond the C-C shell, constitutes the "evaporator" part of the heat pipe, while the section inside the shell constitutes the condenser of the heat pipe (see figure).

FinFET and UTBB for RF SOI communication systems

NASA Astrophysics Data System (ADS)

Raskin, Jean-Pierre

2016-11-01

Performance of RF integrated circuit (IC) is directly linked to the analog and high frequency characteristics of the transistors, the quality of the back-end of line process as well as the electromagnetic properties of the substrate. Thanks to the introduction of the trap-rich high-resistivity Silicon-on-Insulator (SOI) substrate on the market, the ICs requirements in term of linearity are fulfilled. Today partially depleted SOI MOSFET is the mainstream technology for RF SOI systems. Future generations of mobile communication systems will require transistors with better high frequency performance at lower power consumption. The advanced MOS transistors in competition are FinFET and Ultra Thin Body and Buried oxide (UTBB) SOI MOSFETs. Both devices have been intensively studied these last years. Most of the reported data concern their digital performance. In this paper, their analog/RF behavior is described and compared. Both show similar characteristics in terms of transconductance, Early voltage, voltage gain, self-heating issue but UTBB outperforms FinFET in terms of cutoff frequencies thanks to their relatively lower fringing parasitic capacitances.

Stress engineering in GaN structures grown on Si(111) substrates by SiN masking layer application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szymański, Tomasz, E-mail: tomasz.szymanski@pwr.edu.pl; Wośko, Mateusz; Paszkiewicz, Bogdan

2015-07-15

GaN layers without and with an in-situ SiN mask were grown by using metal organic vapor phase epitaxy for three different approaches used in GaN on silicon(111) growth, and the physical and optical properties of the GaN layers were studied. For each approach applied, GaN layers of 1.4 μm total thickness were grown, using silan SiH{sub 4} as Si source in order to grow Si{sub x}N{sub x} masking layer. The optical micrographs, scanning electron microscope images, and atomic force microscope images of the grown samples revealed cracks for samples without SiN mask, and micropits, which were characteristic for the samples grownmore » with SiN mask. In situ reflectance signal traces were studied showing a decrease of layer coalescence time and higher degree of 3D growth mode for samples with SiN masking layer. Stress measurements were conducted by two methods—by recording micro-Raman spectra and ex-situ curvature radius measurement—additionally PLs spectra were obtained revealing blueshift of PL peak positions with increasing stress. The authors have shown that a SiN mask significantly improves physical and optical properties of GaN multilayer systems reducing stress in comparison to samples grown applying the same approaches but without SiN masking layer.« less

Local Dkk1 Crosstalk from Breeding Ornaments Impedes Regeneration of Injured Male Zebrafish Fins

PubMed Central

Kang, Junsu; Nachtrab, Gregory; Poss, Kenneth D.

2013-01-01

SUMMARY Precise spatiotemporal regulation of signaling activators and inhibitors can help limit developmental crosstalk between neighboring tissues during morphogenesis, homeostasis, and regeneration. Here, we find that the secreted Wnt inhibitor Dkk1b is abundantly produced by dense regions of androgen-regulated epidermal tubercles (ET) on the surfaces of adult male zebrafish pectoral fins. High-speed videos and amputation experiments reveal that pectoral fins and their ET are employed for male spawning. Formation and vigorous turnover of ET involve Dkk1b induction and maintenance, whereas Dkk1b is typically restricted from the regeneration blastema after amputation injury. When amputation occurs through an ET-containing region, a Dkk1b-enriched wound epidermis forms and blastema formation is disrupted, compromising regeneration. Thus, homeostatic signaling by key breeding ornaments can interfere with injury-activated tissue regeneration. Our findings help explain sexually dimorphic fin regeneration in zebrafish, and have implications for how regenerative potential might decline as development progresses or during species evolution. PMID:24135229

Mature osteoblasts dedifferentiate in response to traumatic bone injury in the zebrafish fin and skull.

PubMed

Geurtzen, Karina; Knopf, Franziska; Wehner, Daniel; Huitema, Leonie F A; Schulte-Merker, Stefan; Weidinger, Gilbert

2014-06-01

Zebrafish have an unlimited capacity to regenerate bone after fin amputation. In this process, mature osteoblasts dedifferentiate to osteogenic precursor cells and thus represent an important source of newly forming bone. By contrast, differentiated osteoblasts do not appear to contribute to repair of bone injuries in mammals; rather, osteoblasts form anew from mesenchymal stem cells. This raises the question whether osteoblast dedifferentiation is specific to appendage regeneration, a special feature of the lepidotrichia bone of the fish fin, or a process found more generally in fish bone. Here, we show that dedifferentiation of mature osteoblasts is not restricted to fin regeneration after amputation, but also occurs during repair of zebrafish fin fractures and skull injuries. In both models, mature osteoblasts surrounding the injury downregulate the expression of differentiation markers, upregulate markers of the pre-osteoblast state and become proliferative. Making use of photoconvertible Kaede protein as well as Cre-driven genetic fate mapping, we show that osteoblasts migrate to the site of injury to replace damaged tissue. Our findings suggest a fundamental role for osteoblast dedifferentiation in reparative bone formation in fish and indicate that adult fish osteoblasts display elevated cellular plasticity compared with mammalian bone-forming cells. © 2014. Published by The Company of Biologists Ltd.

Design and testing a high fuel volume fraction, externally finned, thermionic emitter.

NASA Technical Reports Server (NTRS)

Peelgren, M. L.; Ernst, D. M.

1971-01-01

A prototypical, high fuel volume fraction, thermionic emitter body was designed and tested. The emitter body is all tungsten, with a 1.40-cm ID, a 3.23-cm OD, and eight full-length axial fins. The emitter thickness is 0.15 cm while the fins and outer clad are 0.075 cm thick. Different methods of fabrication were used in making the test samples. Stress analysis was performed with a three-dimensional elastic code. Thermal testing of the samples, duplicating calculated radial temperature gradients, heatup and cooldown rates, and emitter body temperatures in operation, was performed with no structural failures noted (six heatup and cooldown cycles per sample). Further emitter analysis and testing is planned.

Finite Element Approach for the Design of Control Algorithms for Vertical Fin Buffeting Using Strain Actuation

DTIC Science & Technology

2001-06-01

Algorithms for Vertical Fin Buffeting Using Strain Actuation DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the...UNCLASSIFIED 8-1 Finite Element Approach for the Design of Control Algorithms for Vertical Fin Buffeting Using Strain Actuation Fred Nitzsche...groups), the disturbance (buffet load), and the two output variables (a choice among four Introduction accelerometers and five strain - gauge positions

Tracing the spatio-temporal dynamics of endangered fin whales (Balaenoptera physalus) within baleen whale (Mysticeti) lineages: a mitogenomic perspective.

PubMed

Yu, Jihyun; Nam, Bo-Hye; Yoon, Joon; Kim, Eun Bae; Park, Jung Youn; Kim, Heebal; Yoon, Sook Hee

2017-12-01

To explore the spatio-temporal dynamics of endangered fin whales (Balaenoptera physalus) within the baleen whale (Mysticeti) lineages, we analyzed 148 published mitochondrial genome sequences of baleen whales. We used a Bayesian coalescent approach as well as Bayesian inferences and maximum likelihood methods. The results showed that the fin whales had a single maternal origin, and that there is a significant correlation between geographic location and evolution of global fin whales. The most recent common female ancestor of this species lived approximately 9.88 million years ago (Mya). Here, North Pacific fin whales first appeared about 7.48 Mya, followed by a subsequent divergence in Southern Hemisphere approximately 6.63 Mya and North Atlantic about 4.42 Mya. Relatively recently, approximately 1.76 and 1.42 Mya, there were two additional occurrences of North Pacific populations; one originated from the Southern Hemisphere and the other from an uncertain location. The evolutionary rate of this species was 1.002 × 10 -3 substitutions/site/My. Our Bayesian skyline plot illustrates that the fin whale population has the rapid expansion event since ~ 2.5 Mya, during the Quaternary glaciation stage. Additionally, this study indicates that the fin whale has a sister group relationship with humpback whale (Meganoptera novaeangliae) within the baleen whale lineages. Of the 16 genomic regions, NADH5 showed the most powerful signal for baleen whale phylogenetics. Interestingly, fin whales have 16 species-specific amino acid residues in eight mitochondrial genes: NADH2, COX2, COX3, ATPase6, ATPase8, NADH4, NADH5, and Cytb.

Skeletal development and abnormalities of the vertebral column and of the fins in hatchery-reared turbot Scophthalmus maximus.

PubMed

Tong, X H; Liu, Q H; Xu, S H; Ma, D Y; Xiao, Z Z; Xiao, Y S; Li, J

2012-03-01

To describe the skeletal development and abnormalities in turbot Scophthalmus maximus, samples were collected every day from hatching to 60 days after hatching (DAH). A whole-mount cartilage and bone-staining technique was used. Vertebral ontogeny started with the formation of anterior haemal arches at 5·1 mm standard length (L(S) ) c. 11 DAH, and was completed by the full attainment of parapophyses at 16·9 mm L(S) c. 31 DAH. Vertebral centra started to develop at 6·3 mm L(S) c. 16 DAH and ossification in all centra was visible at 11·0 mm L(S) c. 25 DAH. The caudal fin appeared at 5·1 mm L(S) c. 11 DAH and ossification was visible at 20·6 mm L(S) c. 37 DAH. The onset of dorsal and anal fin elements appeared at 5·8 mm L(S) c. 15 DAH and 6·3 mm L(S) c. 16 DAH, respectively. Ossifications of both dorsal fin and anal fin were visible at 20·6 mm L(S) c. 37 DAH. The pectorals were the only fins present before first feeding, their ossifications were completed at 23·5 mm L(S) c. 48 DAH. Pelvic fins began forming at 7·2 mm L(S) c. 19 DAH and calcification of the whole structure was visible at 19·8 mm L(S) c. 36 DAH. In the present study, 24 types of skeletal abnormalities were observed. About 51% of individuals presented skeletal abnormalities, and the highest occurrence was found in the haemal region of the vertebral column. As for each developmental stage, the most common abnormalities were in the dorsal fin during early metamorphic period (stage 2), vertebral fusion during climax metamorphosis (stage 3) and caudal fin abnormality during both late-metamorphic period (stage 4) and post-metamorphic period (stage 5). Such research will be useful for early detection of skeletal malformations during different growth periods of reared S. maximus. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Characterization of Radial Curved Fin Heat Sink under Natural and Forced Convection

NASA Astrophysics Data System (ADS)

Khadke, Rishikesh; Bhole, Kiran

2018-02-01

Heat exchangers are important structures widely used in power plants, food industries, refrigeration, and air conditioners and now widely used in computing systems. Finned type of heat sink is widely used in computing systems. The main aim of the design of the heat sink is to maintain the optimum temperature level. To achieve this goal so many geometrical configurations are implemented. This paper presents a characterization of radially curved fin heat sink under natural and forced convection. Forced convection is studied for the optimization of temperature for better efficiency. The different alternatives in geometry are considered in characterization are heat intensity, the height of the fin and speed of the fan. By recognizing these alternatives the heat sink is characterized by the heat flux usually generated in high-end PCs. The temperature drop characteristics across height and radial direction are presented for the constant heat input and air flow in the heat sink. The effect of dimensionless elevation height (0 ≤ Z* ≤ 1) and Elenbaas Number (0.4 ≤ El ≤ 2.8) of the heat sink were investigated for study of the Nusselt number. Based on experimental characterization, process plan has been developed for the selection of the similar heat sinks for desired output (heat dissipation and temperature distribution).

Study on turbulent flow and heat transfer performance of tubes with internal fins in EGR cooler

NASA Astrophysics Data System (ADS)

Liu, Lin; Ling, Xiang; Peng, Hao

2015-07-01

In this paper, flow and heat transfer performances of the tubes with internal longitudinal fins in Exhaust Gas Recirculation (EGR ) cooler were investigated by three-dimension computation and experiment . Each test tube was a single-pipe structure, without inner tube. Three-dimension computation was performed to determine the thermal characteristics difference between the two kinds of tubes, that is, the tube with an inner solid staff as a blocked structure and the tube without the blocked structure. The effects of fin width and fin height on heat transfer and flow are examined. For proving the validity of numerical method, the calculated results were compared with corresponding experimental data. The tube-side friction factor and heat transfer coefficient were examined. As a result, the maximum deviations between the numerical results and the experimental data are approximately 5.4 % for friction factor and 8.6 % for heat transfer coefficient, respectively. It is found that two types of internally finned tubes enhance significantly heat transfer. The heat transfer of the tube with blocked structure is better, while the pressure drop of the tube without blocked structure is lower. The comprehensive performance of the unblocked tube is better to applied in EGR cooler.

Heat transfer enhancement in triplex-tube latent thermal energy storage system with selected arrangements of fins

NASA Astrophysics Data System (ADS)

Zhao, Liang; Xing, Yuming; Liu, Xin; Rui, Zhoufeng

2018-01-01

The use of thermal energy storage systems can effectively reduce energy consumption and improve the system performance. One of the promising ways for thermal energy storage system is application of phase change materials (PCMs). In this study, a two-dimensional numerical model is presented to investigate the heat transfer enhancement during the melting/solidification process in a triplex tube heat exchanger (TTHX) by using fluent software. The thermal conduction and natural convection are all taken into account in the simulation of the melting/solidification process. As the volume fraction of fin is kept to be a constant, the influence of proposed fin arrangement on temporal profile of liquid fraction over the melting process is studied and reported. By rotating the unit with different angle, the simulation shows that the melting time varies a little, which means that the installation error can be reduced by the selected fin arrangement. The proposed fin arrangement also can effectively reduce time of the solidification of the PCM by investigating the solidification process. To summarize, this work presents a shape optimization for the improvement of the thermal energy storage system by considering both thermal energy charging and discharging process.

Thermal management optimization of an air-cooled Li-ion battery module using pin-fin heat sinks for hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Mohammadian, Shahabeddin K.; Zhang, Yuwen

2015-01-01

Three dimensional transient thermal analysis of an air-cooled module that contains prismatic Li-ion cells next to a special kind of aluminum pin fin heat sink whose heights of pin fins increase linearly through the width of the channel in air flow direction was studied for thermal management of Lithium-ion battery pack. The effects of pin fins arrangements, discharge rates, inlet air flow velocities, and inlet air temperatures on the battery were investigated. The results showed that despite of heat sinks with uniform pin fin heights that increase the standard deviation of the temperature field, using this kind of pin fin heat sink compare to the heat sink without pin fins not only decreases the bulk temperature inside the battery, but also decreases the standard deviation of the temperature field inside the battery as well. Increasing the inlet air temperature leads to decreasing the standard deviation of the temperature field while increases the maximum temperature of the battery. Furthermore, increasing the inlet air velocity first increases the standard deviation of the temperature field till reaches to the maximum point, and after that decreases. Also, increasing the inlet air velocity leads to decrease in the maximum temperature of the battery.

Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data.

PubMed

Ferrón, Humberto G; Martínez-Pérez, Carlos; Botella, Héctor

2017-01-01

Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well-ossified endoskeleton in a large number of groups hinder the preservation of complete specimens. Previous reconstructions of most early vertebrates known from partial remains have been wholly based on phylogenetically closely related taxa. However, body design of fishes is determined, to a large extent, by their swimming mode and feeding niche, making it possible to recognise different morphological traits that have evolved several times in non-closely related groups with similar lifestyles. Based on this well-known ecomorphological correlation, here we propose a useful comparative framework established on extant taxa for predicting some anatomical aspects in extinct aquatic vertebrates from palaeoecological data and vice versa. For this, we have assessed the relationship between the locomotory patterns and the morphological variability of the caudal region in extant sharks by means of geometric morphometrics and allometric regression analysis. Multivariate analyses reveal a strong morphological convergence in non-closely related shark species that share similar modes of life, enabling the characterization of the caudal fin morphology of different ecological subgroups. In addition, interspecific positive allometry, affecting mainly the caudal fin span, has been detected. This phenomenon seems to be stronger in sharks with more pelagic habits, supporting its role as a compensation mechanism for the loss of hydrodynamic lift associated with the increase in body size, as previously suggested for many other living and extinct aquatic vertebrates. The quantification of shape change per unit size in each ecological subgroup has allowed us to establish a basis for inferring not only qualitative aspects of the caudal fin

Effects of 17β-trenbolone on Eastern and Western mosquitofish (Gambusia holbrooki and G. affinis) anal fin growth and gene expression patterns.

PubMed

Brockmeier, Erica K; Ogino, Yukiko; Iguchi, Taisen; Barber, David S; Denslow, Nancy D

2013-03-15

The Eastern and Western mosquitofish (Gambusia holbrooki and G. affinis) are potential bioindicator organisms for endocrine disruptors. Male mosquitofish have an elongated anal fin (gonopodium) used for internal fertilization whose formation is driven by androgens. Normal female mosquitofish have a normal, rounded anal fin which undergoes elongation into a gonopodium structure when female mosquitofish are exposed to androgenic chemicals. Significant issues with using mosquitofish as a bioindicator include the lack of knowledge on how anal fin growth in females corresponds to endpoints relevant to biological integrity and the lack of information on the molecular pathways that regulate anal fin growth. The objectives of this study were to understand how androgen-induced anal fin elongation relates to changes in endpoints related to the female reproductive system and to understand how anal fin elongation occurs in androgen-exposed female mosquitofish. To achieve these objectives, adult female G. holbrooki were exposed to a vehicle control or one of three doses of the androgen 17β-trenbolone (TB) at nominal concentrations of 0.1, 1 or 10 μg TB/L. Anal fin measurements were taken and livers were used for quantitative polymerase chain reaction analysis of vitellogenin (vtg) mRNA expression at multiple time points. 10 μg TB/L induced anal fin elongation after 7 days of treatment (one-way ANOVA, p<0.05) as did 0.1 and 1 μg TB/L at later time points (one-way ANOVA, p<0.05). 10 μg TB/L significantly reduced hepatic vtg gene expression at all time points assessed (one-way ANOVA, p<0.05). There was no correlation between anal fin elongation levels and vtg gene expression (Spearman's ρ, p>0.05). In a separate experiment, female G. holbrooki and G. affinis were exposed to the vehicle control or 1 μg TB/L. Anal fins were used for qualitative gene expression analysis of the genes sonic hedgehog (shh), muscle segment homeobox C (msxC), and fibroblast growth factor receptor 1

20-Hz pulses and other vocalizations of fin whales, Balaenoptera physalus, in the Gulf of California, Mexico.

PubMed

Thompson, P O; Findley, L T; Vidal, O

1992-12-01

Low-frequency vocalizations were recorded from fin whales, Balaenoptera physalus, in the Gulf of California, Mexico, during three cruises. In March 1985, recorded 20-Hz pulses were in sequences of regular 9-s interpulse intervals. In August 1987, nearly all were in sequences of doublets with alternating 5- and 18-s interpulse intervals. No 20-Hz pulse sequences of any kind were detected in February 1987. The typical pulse modulated from 42 to 20 Hz and its median duration was 0.7 s (1985 data). Most other fin whale sounds were also short tonal pulses averaging 82, 56, and 68 Hz, respectively, for the three cruises; 89% were modulated in frequency, mostly downward. Compared to Atlantic and Pacific Ocean regions, Gulf of California 20-Hz pulses were unique in terms of frequency modulation, interpulse sound levels, and temporal patterns. Fin whales in the Gulf may represent a regional stock revealed by their sound characteristics, a phenomenon previously shown for humpback whales, birds, and fish. Regional differences in fin whale sounds were found in comparisons of Atlantic and Pacific locations.

Large electron concentration modulation using capacitance enhancement in SrTiO{sub 3}/SmTiO{sub 3} Fin-field effect transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, Amit, E-mail: averma@cornell.edu; Nomoto, Kazuki; School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853

2016-05-02

Solid-state modulation of 2-dimensional electron gases (2DEGs) with extreme (∼3.3 × 10{sup 14 }cm{sup −2}) densities corresponding to 1/2 electron per interface unit cell at complex oxide heterointerfaces (such as SrTiO{sub 3}/GdTiO{sub 3} or SrTiO{sub 3}/SmTiO{sub 3}) is challenging because it requires enormous gate capacitances. One way to achieve large gate capacitances is by geometrical capacitance enhancement in fin structures. In this work, we fabricate both Au-gated planar field effect transistors (FETs) and Fin-FETs with varying fin-widths on 60 nm SrTiO{sub 3}/5 nm SmTiO{sub 3} thin films grown by hybrid molecular beam epitaxy. We find that the FinFETs exhibit higher gate capacitance comparedmore » to planar FETs. By scaling down the SrTiO{sub 3}/SmTiO{sub 3} fin widths, we demonstrate further gate capacitance enhancement, almost twice compared to the planar FETs. In the FinFETs with narrowest fin-widths, we demonstrate a record 2DEG electron concentration modulation of ∼2.4 × 10{sup 14 }cm{sup −2}.« less

Development and verification of real-time controllers for the F/A-18 vertical fin buffet load alleviation

NASA Astrophysics Data System (ADS)

Chen, Yong; Viresh, Wickramasinghe; Zimcik, David

2006-03-01

Twin-tail fighter aircraft such as the F/A-18 may experience intense buffet loads at high angles of attack flight conditions and the broadband buffet loads primarily excite the first bending and torsional modes of the vertical fin that results in severe vibration and dynamic stresses on the vertical fin structures. To reduce the premature fatigue failure of the structure and to increase mission availability, a novel hybrid actuation system was developed to actively alleviate the buffet response of a full-scale F/A-18 vertical fin. A hydraulic rudder actuator was used to control the bending mode of the fin by engaging the rudder inertial force. Multiple Macro Fiber Composites actuators were surface mounted to provide induced strain actuation authority to control the torsional mode. Experimental system identification approach was selected to obtain a state-space model of the system using open-loop test data. An LQG controller was developed to minimize the dynamic response of the vertical fin at critical locations. Extensive simulations were conducted to evaluate the control authority of the actuators and the performance of the controller under various buffet load cases and levels. Closed-loop tests were performed on a full-scale F/A-18 empennage and the results validated the effectiveness of the real-time controller as well as the development methodology. In addition, the ground vibration test demonstrated that the hybrid actuation system is a feasible solution to alleviate the vertical tail buffet loads in high performance fighter aircraft.

Spray Cooling Trajectory Angle Impact Upon Heat Flux Using a Straight Finned Enhanced Surface

NASA Technical Reports Server (NTRS)

Silk, Eric A.; Kim, Jungho; Kiger, Ken

2005-01-01

Experiments were conducted to study the effects of spray trajectory angles upon heat flux for flat and enhanced surface spray cooling. The surface enhancement consisted of straight fins machined on the top surface of a copper heater block. Spray cooling curves were obtained with the straight fin surface aligned both parallel (axial) and perpendicular (transverse) to the spray axis. Measurements were also obtained on a flat surface heater block for comparison purposes. Each copper block had a cross-sectional area of 2.0 sq cm. A 2x2 nozzle array was used with PF-5060 as the working fluid. Thermal performance data was obtained under nominally degassed (chamber pressure of 41.4 kPa) conditions. Results show that the maximum CHF in all cases was attained for a trajectory angle of 30' from the surface normal. Furthermore, trajectory angles applied to straight finned surfaces can have a critical heat flux (CHF) enhancement as much as 75% (heat flux value of 140 W/sq cm) relative to the vertical spray orientation for the analogous flat surface case under nominally degassed conditions.

Fabrication of high-quality superconductor-insulator-superconductor junctions on thin SiN membranes

NASA Technical Reports Server (NTRS)

Garcia, Edouard; Jacobson, Brian R.; Hu, Qing

1993-01-01

We have successfully fabricated high-quality and high-current density superconductor-insulator-superconductor (SIS) junctions on freestanding thin silicon nitride (SIN) membranes. These devices can be used in a novel millimeter-wave and THz receiver system which is made using micromachining. The SIS junctions with planar antennas were fabricated first on a silicon wafer covered with a SiN membrane, the Si wafer underneath was then etched away using an anisotropic KOH etchant. The current-voltage characteristics of the SIS junctions remained unchanged after the whole process, and the junctions and the membrane survived thermal cycling.

Back scattering involving embedded silicon nitride (SiN) nanoparticles for c-Si solar cells

NASA Astrophysics Data System (ADS)

Ghosh, Hemanta; Mitra, Suchismita; Siddiqui, M. S.; Saxena, A. K.; Chaudhuri, Partha; Saha, Hiranmay; Banerjee, Chandan

2018-04-01

A novel material, structure and method of synthesis for dielectric light trapping have been presented in this paper. First, the light scattering behaviour of silicon nitride nanoparticles have been theoretically studied in order to find the optimized size for dielectric back scattering by FDTD simulations from Lumerical Inc. The optical results have been used in electrical analysis and thereby, estimate the effect of nanoparticles on efficiency of the solar cells depending on substrate thickness. Experimentally, silicon nitride (SiN) nanoparticles have been formed using hydrogen plasma treatment on SiN layer deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD). The size and area coverage of the nanoparticles were controlled by varying the working pressure, power density and treatment duration. The nanoparticles were integrated with partial rear contact c-Si solar cells as dielectric back reflector structures for the light trapping in thin silicon solar cells. Experimental results revealed the increases of current density by 2.7% in presence of SiN nanoparticles.

Assessment of Caudal Fin Clips as a Non-lethal Technique for Predicting Muscle Tissue Mercury Concentrations in Largeouth Bass

EPA Science Inventory

The statistical relationship between total mercury (Hg) concentration in clips from the caudal fin and muscle tissue of largemouth bass (Micropterus salmoides) from 26 freshwater sites in Rhode Island, USA was developed and evaluated to determine the utility of fin clip analysis ...

Skeletal ontogeny of the vertebral column and of the fins in shi drum Umbrina cirrosa (Teleostei: Perciformes: Sciaenidae), a new candidate species for aquaculture.

PubMed

Neofytou, M; Sfakianakis, D G; Koumoundouros, G; Mylonas, C C; Kentouri, M

2017-09-01

The osteological development of the vertebral column and fins in shi drum Umbrina cirrosa was studied in order to improve knowledge for its introduction in Mediterranean aquaculture. The osteological development was studied in 171 individuals, of total length (L T ) from 2·7 to 30·2 mm that were reared under the mesocosm technique. Vertebral ontogeny starts at 3·4 and 4·0 mm L T , with the formation of the first cartilaginous neural and haemal arches, and spines, respectively, and is completed with the full attainment of epicentrals (12·5 mm L T ). The formation of vertebral centra occurs between 4·1 and 7·4 mm L T . Pectoral supports are the first fin elements to develop (3·0 mm L T ), followed by those of the caudal fin (3·8 mm L T ), pelvic fin (3·9 mm L T ) and finally by those of the dorsal and anal fins (4·5 mm L T ). The caudal fin is the first to develop fin rays and attain the full count of principal fin rays (4·5-6·8 mm L T ), but the last to be fully completed with the formation of procurrent fin rays (6·9-17·5 mm L T ). The next fins starting to present rays are the dorsal (5·3 mm L T ) and the pectoral fins (5·6 mm L T ), while the anal and pelvic fins are the last (5·7 mm L T ). Following the caudal principal fin rays (6·8 mm L T ), the dorsal, anal (6·9 mm L T ), pelvic (7·4 mm L T ) and pectoral fins (9·8 mm L T ) are the next with fully completed ray counts. Aggregation of qualitative changes, such as the appearance of cartilages, the beginning and the complement of the ossification process and the full complement of elements in U. cirrosa were measured as cumulative frequency counts. These measurements reveal three ontogenetic intervals: one very developmentally active period during early life stages (from 3 to 5·9 mm L T ), a second slower developmental period (from 6·0 to 8·9 mm L T ) and finally a period of ontogeny more focused on structure refinement up to metamorphosis and settlement (>9·0 mm L T ). © 2017 The

Virtues of SIN: Can Intensified Public Efforts Help Disadvantaged Immigrants?

ERIC Educational Resources Information Center

Aslund, Olof; Johansson, Per

2011-01-01

The labor market integration of immigrants is a top political priority throughout the Organization for Economic Cooperation and Development (OECD) countries. Social and fiscal gains, as well as sustained future labor supply make governments search for effective policies to increase employment among the mostly disadvantaged. The author studies SIN,…

Shp2–Mitogen-Activated Protein Kinase Signaling Drives Proliferation during Zebrafish Embryo Caudal Fin Fold Regeneration

PubMed Central

Hale, Alexander James

2017-01-01

ABSTRACT Regeneration of the zebrafish caudal fin following amputation occurs through wound healing, followed by formation of a blastema, which produces cells to replace the lost tissue in the final phase of regenerative outgrowth. We show that ptpn11a−/− ptpn11b−/− zebrafish embryos, lacking functional Shp2, fail to regenerate their caudal fin folds. Rescue experiments indicated that Shp2a has a functional signaling role, requiring its catalytic activity and SH2 domains but not the two C-terminal tyrosine phosphorylation sites. Surprisingly, expression of Shp2a variants with increased and reduced catalytic activity, respectively, rescued caudal fin fold regeneration to similar extents. Expression of mmp9 and junbb, indicative of formation of the wound epidermis and distal blastema, respectively, suggested that these processes occurred in ptpn11a−/− ptpn11b−/− zebrafish embryos. However, cell proliferation and MAPK phosphorylation were reduced. Pharmacological inhibition of MEK1 in wild-type zebrafish embryos phenocopied loss of Shp2. Our results suggest an essential role for Shp2a–mitogen-activated protein kinase (MAPK) signaling in promoting cell proliferation during zebrafish embryo caudal fin fold regeneration. PMID:29203641

Comparison of heat transfer coefficients of open micro-channels and plain micro-fins

NASA Astrophysics Data System (ADS)

Kaniowski, Robert; Pastuszko, Robert

2018-06-01

The paper describes results of analysis of pool boiling heat transfer on enhanced surfaces. Two types of structural surfaces were used: open microchannel surfaces consisting of a system of parallel micro-channels 0.3 mm wide, from 0.2 to 0.5 mm deep and with a pitch of 0.6 mm, and plain micro-fins 0.5 mm in height, uniformly spaced on the base surface with a spacing from 0.6 to1.5 mm. Pool boiling data at atmospheric pressure were obtained for saturated water, ethanol and FC-72. The effects of micro-channel/micro-fin dimensions on heat transfer coefficient in nucleate pool boiling were examined. Substantial enhancement of heat transfer coefficient was observed.

New Design Heaters Using Tubes Finned by Deforming Cutting Method

NASA Astrophysics Data System (ADS)

Zubkov, N. N.; Nikitenko, S. M.; Nikitenko, M. S.

2017-10-01

The article describes the results of research aimed at selecting and assigning technological processing parameters for obtaining outer fins of heat-exchange tubes by the deformational cutting method, for use in a new design of industrial water-air heaters. The thermohydraulic results of comparative engineering tests of new and standard design air-heaters are presented.

Study of 3D-growth conditions for selective area MOVPE of high aspect ratio GaN fins with non-polar vertical sidewalls

NASA Astrophysics Data System (ADS)

Hartmann, Jana; Steib, Frederik; Zhou, Hao; Ledig, Johannes; Nicolai, Lars; Fündling, Sönke; Schimpke, Tilman; Avramescu, Adrian; Varghese, Tansen; Trampert, Achim; Straßburg, Martin; Lugauer, Hans-Jürgen; Wehmann, Hergo-Heinrich; Waag, Andreas

2017-10-01

GaN fins are 3D architectures elongated in one direction parallel to the substrate surface. They have the geometry of walls with a large height to width ratio as well as small footprints. When appropriate symmetry directions of the GaN buffer are used, the sidewalls are formed by non-polar {1 1 -2 0} planes, making the fins particularly suitable for many device applications like LEDs, FETs, lasers, sensors or waveguides. The influence of growth parameters like temperature, pressure, V/III ratio and total precursor flow on the fin structures is analyzed. Based on these results, a 2-temperature-step-growth was developed, leading to fins with smooth side and top facets, fast vertical growth rates and good homogeneity along their length as well as over different mask patterns. For the core-shell growth of fin LED heterostructures, the 2-temperature-step-growth shows much smoother sidewalls and less crystal defects in the InGaN QW and p-GaN shell compared to structures with cores grown in just one step. Electroluminescence spectra of the 2-temperature-step-grown fin LED are demonstrated.

Influence of the direct NO-donor SIN-1 on the interaction between platelets and stainless steel stents under dynamic conditions.

PubMed

Jung, F; Mrowietz, C; Seyfert, U T; Grewe, R; Franke, R P

2003-01-01

It was investigated whether the NO-donor SIN-1, the active metabolite of molsidomine, influenced the activation of platelets, the formation of circulating platelet aggregates, the spontaneous aggregation of platelets and the activation of the clotting system triggered by a body foreign surface in an in vitro closed-loop perfusion model. With human platelet-rich plasma at micromolar concentrations SIN-1 exerted pronounced effects on the interaction between platelets and an exogenous surface. In the absence of SIN-1, the number of circulating single platelets decreased significantly, which could be due either to the formation of circulating platelet aggregates or to the adhesion of platelets to the stent. Both these processes were blocked by the addition of SIN-1. Moreover, the platelets exhibited hyperaggregability in the absence of SIN-1 whereas the NO-donor was able to completely inhibit spontaneous platelet aggregation. Similar results were obtained in flow cytometry experiments. Without SIN-1, high platelet surface densities of both the GPIb/IX and GPIIb/IIIa receptors were observed. In addition, the density of the fibrinogen receptor increased significantly with the number of perfusion cycles. SIN-1 was able to suppress the augmented GPIIb/IIIa receptor expression significantly. Molsidomine seemed to have the potential to reduce the incidence of thrombotic processes triggered by the exogenous surface of the stent.

FIN-EPOS - Finnish national initiative of the European Plate Observing System: Bringing Finnish solid Earth infrastructures into EPOS

NASA Astrophysics Data System (ADS)

Vuorinen, Tommi; Korja, Annakaisa

2017-04-01

FIN-EPOS consortium is a joint community of Finnish national research institutes tasked with operating and maintaining solid-earth geophysical and geological observatories and laboratories in Finland. These national research infrastructures (NRIs) seek to join EPOS research infrastructure (EPOS RI) and further pursue Finland's participation as a founding member in EPOS ERIC (European Research Infrastructure Consortium). Current partners of FIN-EPOS are the University of Helsinki (UH), the University of and Oulu (UO), Finnish Geospatial Research Institute (FGI) of the National Land Survey (NLS), Finnish Meteorological Institute (FMI), Geological Survey of Finland (GTK), CSC - IT Center for Science and MIKES Metrology at VTT Technical Research Centre of Finland Ltd. The consortium is hosted by the Institute of Seismology, UH (ISUH). The primary purpose of the consortium is to act as a coordinating body between various NRIs and the EPOS RI. FIN-EPOS engages in planning and development of the national EPOS RI and will provide support in EPOS implementation phase (IP) for the partner NRIs. FIN-EPOS also promotes the awareness of EPOS in Finland and is open to new partner NRIs that would benefit from participating in EPOS. The consortium additionally seeks to advance solid Earth science education, technologies and innovations in Finland and is actively engaging in Nordic co-operation and collaboration of solid Earth RIs. The main short term objective of FIN-EPOS is to make Finnish geoscientific data provided by NRIs interoperable with the Thematic Core Services (TCS) in the EPOS IP. Consortium partners commit into applying and following metadata and data format standards provided by EPOS. FIN-EPOS will also provide a national Finnish language web portal where users are identified and their user rights for EPOS resources are defined.

GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.

PubMed

Nornberg, Bruna Félix; Almeida, Daniela Volcan; Figueiredo, Márcio Azevedo; Marins, Luis Fernando

2016-10-01

The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.

Turbulence: does vorticity affect the structure and shape of body and fin propulsors?

PubMed

Webb, P W; Cotel, A J

2010-12-01

Over the past century, many ideas have been developed on the relationships between water flow and the structure and shape of the body and fins of fishes, largely during swimming in relatively steady flows. However, both swimming by fishes and the habitats they occupy are associated with vorticity, typically concentrated as eddies characteristic of turbulent flow. Deployment of methods to examine flow in detail suggests that vorticity impacts the lives of fishes. First, vorticity near the body and fins can increase thrust and smooth variations in thrust that are a consequence of using oscillating and undulating propulsors to swim. Second, substantial mechanical energy is dissipated in eddies in the wake and adaptations that minimize these losses would be anticipated. We suggest that such mechanisms may be found in varying the length of the propulsive wave, stiffening propulsive surfaces, and shifting to using median and paired fins when swimming at low speeds. Eddies in the flow encountered by fishes may be beneficial, but when eddy radii are of the order of 0.25 of the fish's total length, negative impacts occur due to greater difficulties in controlling stability. The archetypal streamlined "fish" shape reduces destabilizing forces for fishes swimming into eddies.

Developmental structure of the vertebral column, fins, scutes and scales in bester sturgeon, a hybrid of beluga Huso huso and sterlet Acipenser ruthenus.

PubMed

Zhang, X; Shimoda, K; Ura, K; Adachi, S; Takagi, Y

2012-11-01

In the larval bester, a hybrid sturgeon of beluga Huso huso and sterlet Acipenser ruthenus, development of cartilage around the notochord began 7 days post hatch (dph) (14.0 mm, total length, L(T)). The vertebral cartilage develops in the following sequence: basidorsals and basiventrals, neural canals, neural spines and ribs. The development of ribs remained incomplete in the largest specimen (181 dph, 179 mm L(T) ) that was examined. Endoskeletal development of the fins began 4 dph for the dorsal and anal fins, 6 dph for the pectoral fin and 10 dph for the caudal and pelvic fins. Complete elements of all fins were observed by 91 dph and complete ossification of fin rays was observed by 122 dph in the double-stained specimens. Observation of the histological sections, however, suggested that ossification occurred soon after the formation of the organic matrix in the fin rays. Dorsal scutes were first visible by 25 dph, followed by the lateral and ventral scutes, which were visible by 37 and 44 dph, respectively. The number of scutes was fixed at 44, 59 and 91 dph and ossification was complete by 59 (dorsal) and 91 dph (lateral and ventral scutes) in the double-stained specimens. Ossification occurred soon after the formation of the scute organic matrix in the histological sections. Four types of scales were observed in the H. huso×A. ruthenus hybrid. Median predorsal, preanal and small scales on the anterior section of the head were visible by 59 dph. Scales on the caudal fin were visible by 91 dph and a variable assemblage of scales anterior to the anal fin was visible by 122 dph. Both the scutes and scales developed in a process that is similar to that of intramembranous ossification. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Effects of control parameters of three-point initiation on the formation of an explosively formed projectile with fins

NASA Astrophysics Data System (ADS)

Li, R.; Li, W. B.; Wang, X. M.; Li, W. B.

2018-03-01

The effects of the initiation diameter and synchronicity error on the formation of fins and stable-flight velocity of an explosively formed projectile (EFP) with three-point initiation are investigated. The pressure and area of the Mach wave acting on the metal liner at different initiation diameters are calculated employing the Whitham method. LS-DYNA software is used to investigate the asymmetric collision of detonation waves resulting from three-point initiation synchronicity error, the distortion characteristics of the liner resulting from the composite detonation waves, and the performance parameters of the EFP with fins. Results indicate that deviations of the Y-shaped high-pressure zone and central ultrahigh-pressure zone from the liner center can be attributed to the error of three-point initiation, which leads to the irregular formation of EFP fins. It is noted that the area of the Mach wave decreases, but the pressure of the Mach wave and the final speed and length-to-diameter ( L/ D) ratio of the EFP increase, benefiting the formation of the EFP fins, as the initiation diameter increases.

Initial Alignment of Large Azimuth Misalignment Angles in SINS Based on Adaptive UPF