Single Fin Research Articles

Investigation on the melting process of phase change material in a square cavity with a single fin attached at the center of the heated wall

In this study, melting of a phase change material (PCM) in a square cavity with a single fin attached at the center of the heated wall is studied numerically employing the enthalpy-porosity method. The opposite wall to the heated wall in the square cavity is cold. The other two adjacent walls are thermally insulated. Paraffin wax is chosen as a PCM due to its demonstrable favorable properties. The thermophysical properties of the paraffin wax are assumed to be a dual function of temperature and phase. The influence of the fin length on the melting process of the paraffin wax is examined. Moreover, the orientation of the square cavity on the melting process is scrutinized. The numerical results elucidate that the melting rates increase significantly by embedding the fin into the paraffin wax. As the fin length is incremented, the melting rate intensifies considerably during the early stages of melting. However, the effect of the fin length on the melting rate diminishes after a long period of heating has happened. It is also observed that the melting rate can be augmented significantly by changing the orientation of the heated wall in the square cavity.

Electrical characterization of single nanometer-wide Si fins in dense arrays.

This paper demonstrates the development of a methodology using the micro four-point probe (μ4PP) technique to electrically characterize single nanometer-wide fins arranged in dense arrays. We show that through the concept of carefully controlling the electrical contact formation process, the electrical measurement can be confined to one individual fin although the used measurement electrodes physically contact more than one fin. We demonstrate that we can precisely measure the resistance of individual ca. 20 nm wide fins and that we can correlate the measured variations in fin resistance with variations in their nanometric width. Due to the demonstrated high precision of the technique, this opens the prospect for the use of μ4PP in electrical critical dimension metrology.

On the Hydrodynamics of Anomalocaris Tail Fins.

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 with 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.

Effect of fin and electrodes on electro-hydrodynamic enhanced heat transfer in enclosures

In this work, enhancement of heat transfer in partially open finned enclosures with single fin and multiple fins was investigated experimentally. Five faces of the enclosure were insulated thermally and electrically; while one face was copper finned plate with an aperture located at its opposite face. Various parameters were considered like supplied current, electrode arrangement, number of fins, and different types of corona discharge. It was concluded that the heat transfer is enhanced while the supplied current is increased. Moreover, higher number of fins can lead to more enhancement of the ratio of heat transfer caused by electrohydrodynamic (EHD) technique. Finally, it was observed that the best location for electrodes is in front of the fins.

Experimental and numerical study about local heat transfer in a microchannel with a pin fin

Local single-phase flow heat transfer downstream a single pin fin in a microchannel was experimentally and numerically studied. Three distinct flow regimes, depending on the Reynolds number, were characterized, namely: laminar flow with steady wake, laminar flow with unsteady wake, and turbulent flow. Local temperature measurements with high spatial resolution were obtained by incorporating an array of micro resistance temperature detectors (RTDs) (∼55 µm × 55 µm) on the internal microchannel surface. Local surface temperatures were related to the flow structures under different flow regimes. An enhanced local heat transfer coefficient at the trailing edge of the wake region downstream the pillar was observed. It is believed to be a result of vortex shedding and large-scale flow mixing triggered by flow instability at high Reynolds number. The numerical model enabled a full conduction/convection conjugate analysis of the entire system including heat conduction within the solid substrates and heat losses to the surrounding environment. Local heat transfer coefficient downstream the pin fin at each Reynolds number was obtained.

Using a shell as a wing: pairing of dissimilar appendages in atlantiid heteropod swimming.

Atlantiid heteropods are zooplanktonic marine snails which have a calcium carbonate shell and single swimming fin. They actively swim to hunt prey and vertically migrate. Previous accounts of atlantiid heteropod swimming described these animals sculling with the swimming fin while the shell passively hung beneath the body. Here, we show, via high-speed stereophotogrammetric measurements of body, fin and shell kinematics, that the atlantiid heteropod Atlanta selvagensis actively flaps both the swimming fin and shell in a highly coordinated wing-like manner in order to swim in the intermediate Reynolds number regime (Re=10-100). The fin and shell kinematics indicate that atlantiid heteropods use unsteady hydrodynamic mechanisms such as clap-and-fling and delayed stall. Unique features of atlantiid heteropod swimming include the coordinated pairing of dissimilar appendages, use of the clap and fling mechanism twice during each stroke cycle, and the fin's extremely large stroke amplitude, which exceeds 180deg.

Effect of Fin Location on the Latent Heat Storage: A Numerical Study

Latent heat thermal energy storage (LHTES) utilizing phase change materials (PCMs) is an appealing approach for the industrial waste heat recovery. However, due to the PCMs’ low thermal conductivity, the heat transfer enhancement methods like inserting metal fins have been widely adopted to fasten the PCMs’ melting. This paper numerically investigates the effect of the single fin location on the PCM’s melting process in a rectangular LHTES unit. The melting fraction contours and evolution curves under the three different fin locations were presented for the comparative analysis. The experiment data from one literature was applied to validate the numerical model and good agreement was found between the numerical results and the experimental data. A series of two-dimensional transient numerical simulations with three different fin locations were then carried out. It was found that the fin location would affect the natural convection process and thus generating the different PCM’s melting speeds. Besides, the fin at the bottom location has the best heat transfer enhancement performance, reducing 3.6 % melting time than the top fin location case. What’s more, the effect of fin location becomes more significant when locating at the bottom half of surface. It was concluded that the fin location could be optimized to improve the overall latent heat storage efficiency.

Estimating the Irish public's willingness to pay for more sustainable salmon produced by integrated multi-trophic aquaculture

Integrated Multi-Trophic Aquaculture (IMTA) has been put forward as a potential sustainable alternative to single fin fish species aquaculture. In IMTA, several species are combined in the production process. Integrating species has a conceivable dual advantage; the environmental impact can be lowered through nutrient cycling and from an economic perspective there is potential for increased efficiency, product diversification and a higher willingness to pay for more environmentally friendly produced salmon. This paper presents the results from a choice experiment which examines whether the Irish public is willing to pay a premium for “sustainably produced” farmed salmon from an IMTA process. Uniquely, an ecolabel was used in the design, based on familiar energy rating labels, to communicate the environmental pressure of fish farming to respondents. The experiment demonstrates that the Irish public has a willingness to pay a price premium for sustainability in salmon farming and for locally produced salmon.

Novel tri-independent-gate FinFET for multi-current modes control

In this paper, a novel tri-independent-gate (TIG) FinFET is presented for multi-current modes control for the first time. The entire integration flow of proposed TIG FinFET is fully compatible with the mainstream gate-first HKMG FinFET process. Five kinds of ON state modes and threshold voltages can be offered by TIG FinFET without additional voltage sources, and it is demonstrated to have a great potential in dynamic voltage SRAM design. The critical electrical parameters of TIG FinFET in different modes are fully investigated with TCAD simulation and compared to the traditional FinFET. TIG FinFET with double fins is found to possess a distinct different output and capacitance characteristics with single fin FinFET. The underlying physical mechanisms are analyzed and investigated in detail.

TCAD Simulation and Analysis of Drain Current and Threshold Voltage in Single Fin and Multi-Fin FinFET

Objectives: This study involves analysis the characteristics of Tri-gate single and double-fin FinFET. It shows the threshold voltage change due to depletion charges. Further, we investigate the effect of increasing number of fins on drain on-off current Methods/Statistical Analysis: In this work, it characterize leakiest path (minimum potential point in the channel) at weak inversion and strong inversion using analytical model. Here, the drain current equation is modelled by considering the effects of the depletion charges in the channel near the Source/Drain and substrate interface. Later, these results are verified using TCAD simulations. Findings: This model is extended for multi-fin FinFET, for analyzing the effect of increasing the number of fins and varying the thickness of fin on the drain ON (at VGS=VDD) current and drain OFF (at VGS=0) current (Leakage current) of trigateFinFET. Finally, it analyze the corner effect in trigateFinFET and propose a solution to reduce it. Application/Improvement: The increase in Threshold voltage with the inclusion of depletion charges. Also, an order increase in drain ON current with two fins keeping the short channel effects minimized.

Experimental investigation of force balance at vapour condensation on a cylindrical fin

Experimental investigation of vapour condensation on single cylindrical fin has been carried out under various gravity conditions: 1g0, 1.8g0 and 0.05g0. For the first time, a balance of forces acting on the condensate flow is analyzed. The fin surface is divided in seven areas, each one being characterized by the main force acting on the liquid motion: gravitational vs surface-tension pressure gradient. The magnitude of the areas does not depend on the gravity level. This confirms the correctness of the fin surface segmentation, as used by various authors, to simplify the condensation modelling. It has been shown that the most intensive vapour condensation takes place in the areas, where the surface-tension pressure gradient is higher than the gravity force. Analysis of the heat load shows that each region affected by the surface-tension pressure gradient provides 10–15% of the total heat load, a contribution that is not negligible and should be taken into account. In case of low gravity, the most intensive condensation takes place at the corner of the fin tip, where the curvature gradient is maximum, and on its cylindrical part. The heat loads in these regions are comparable.

Body-fin interference on the Magnus effect of spinning projectile in supersonic flows

ABSTRACTThe numerical simulations of flow over a spinning finned projectile at angles of attack ranging from to in supersonic conditions were carried out to investigate the flow mechanism of the Magnus effect. The finite volume method, a dual-time stepping method, and a transition model were combined to solve the Reynolds-averaged Navier-Stokes (RANS) equations. The validation of temporal resolution, grid independence, and turbulence models were conducted for the accuracy of the numerical method. The numerical results were in certain agreement with archival experimental data. A comparison of the transient lateral force and time-averaged Magnus force between the body of finned projectile and the nonfinned body, the projectile fin and single fin was given. The key lies in the analysis of the reasons for the production of the Magnus force. The simulation provided a profound insight into the flow structure and revealed the following. The fin leading edge shock contributes to the unsteady interference on body lateral force, while the time-averaged body Magnus force is similar to that of the nonfinned body. At , the shielding effect of body on crossflow weakens the time-averaged body Magnus force induced by asymmetrical flow separation, the magnitude of which is reduced to the value at . The leeward separation vortices and the resistance on wingroot flow are responsible for the nonlinear interference of the projectile body on fin Magnus force at different angles of attack. When the low pressure region of the vortex core is equivalent to the size and position of fin, leeward separation vortices contribute more the time-averaged Magnus force and induce high frequency variation to the transient fin lateral force.

High Performance Three-Dimensional Double-Stacked Multiple-Nanochannel and Quadruple-Nanogate ZnO-Based Fin Metal-Oxide-Semiconductor Field-Effect Transistors

To improve performances of zinc oxide (ZnO)-based metal-oxide-semiconductor field-effect transistors (MOSFETs), the double-stacked multiple-nanochannel and quadruple-nanogate (DMCQG) ZnO-based MOSFETs were fabricated using the laser interference photolithography technique and the hardened photoresist technique. The three dimensional double-stacked structure of the ZnO-based fin MOSFETs possessed the same device area as the single structure. However, the drain-source saturation current and the maximum transconductance of the double-stacked MCQG ZnO-based fin MOSFETs were, respectively, improved from 13.7 mA mm−1 to 25.5 mA mm−1 and from 6.9 mS mm−1 to 13.5 mS mm−1 in compared with the single MCQG ZnO-based fin MOSFETs. Besides, the gate leakage current of both the double-stacked structure and the single structure was kept at the order of nA.

Local heat transfer in a microchannel with a pin fin—experimental issues and methods to mitigate

Local heat transfer downstream a single pin fin in a microchannel was experimentally studied by incorporating an array of micro resistance temperature detectors (RTD) (∼55μm×55μm) on the internal microchannel surface. Local temperature distribution with spatial resolution as high as 150μm was obtained and was superimposed onto the velocity field to reveal the interaction between the flow structure and the local heat transfer at different regions downstream the pin fin. Initial result in which the surface temperature inside the steady wake region was lower than in the regions outside the recirculation zone was explained and linked to an interplay of fluid convection and solid substrate conduction. Ignoring this local interplay and processing the data without careful consideration to the conduction process resulted in misinterpretation of the heat transfer processes. To address this issue numerical thermal and fluid model of the entire device was simulated to provide local heat flux distribution. This in turn allowed to resolve the local heat transfer coefficient in the vicinity, and outside the region, of the pin fin.

Investigation of Three-Dimensional Shock Wave/Turbulent-Boundary-Layer Interaction Initiated by a Single Fin

Three-dimensional shock wave/turbulent-boundary-layer interaction of a hypersonic flow passing a single fin mounted on a flat plate at a Mach number of five and unit Reynolds number was conducted by a large-eddy simulation approach. The performed large-eddy simulation has demonstrated good agreement with experimental data in terms of mean flowfield structures, surface pressure distribution, and surface flow pattern. Furthermore, the shock wave system, flow separation structure, and turbulence characteristics were all investigated by analyzing the obtained large-eddy simulation dataset. It was found that, for this kind of three-dimensional shock wave/turbulent-boundary-layer interaction problem, the flow characteristics in different regions have been dominated by respective wall turbulence, free shear layer turbulence, and corner vortex motions in different regions. In the reverse flow region, near-wall quasi-streamwise streaky structures were observed just beneath the main separation vortex, indicating that the transition of the pathway of the separation flow to turbulence may occur within a short distance from the reattachment location. The obtained large-eddy simulation results have provided a clear and direct evidence of the primary reverse flow and the secondary separation flow being essentially turbulent.

In-Line Resistance Measurement of Single Nanometer-Wide Trenches and Fins

Since the advent of non-planar metal-oxide-semiconductor (MOS) transistors, embodied by the three-dimensional fin field-effect transistors (finFETs), there has been a rising need for fast in-line metrology solutions for the electrical characterization of nanometer-wide trenches filled with semiconducting materials. Indeed, on such narrow structures, conventional four point probe fails, mostly due to the challenging alignment of the four millimeter-sized and -spaced probes to the nanoscale trenches. Subsequently, at the expense of extra processing cost and time, the electrical characterization of these state-of-the-art devices is now performed at metal-1 on fins connected by metal contacts in Kelvin resistor or transmission line structures [1]. However, a very promising technique to solve the need for electrical resistance measurements of narrow fins without the need for metal contacts is the micro four-point probe. This four-point probe technique where the probes and probe distance have been downscaled to a few micrometer size has been successfully applied to a myriad of blanket materials, ranging from multilayered metal stacks [2] to semiconductors [3], two-dimensional materials [4] and even single nanowires [5]. Advantageously, micro-probes have allowed a smaller sampling volume and a minimized sensitivity to junction leakage in blanket samples [6] but they are also much easier to align to nanoscale trenches. In this contribution, we evaluate the capabilities of micro four-point probe, as implemented in the fully automatic microHALL®-A300 tool of CAPRES A/S, for the in-line resistance measurement of single oxide-isolated nanoscale fin-like structures. We start by showing that this tool is capable of contacting the four probes with single fins with widths down to 20 nm, i.e. three orders of magnitude smaller than the total 24 μm distance between the two outermost pins. Next, we investigate the measured resistance values to evaluate whether the measured resistance values can be correctly attributed to the semiconducting material located inside the trench. Many parasitic conduction paths could indeed still lead to the underestimation of the actual resistance of these narrow features. In this paper, we evaluate how to minimize the possible contribution of the two most probable parasitic resistances. First of all, we consider the contribution of multiple fins which could be contacted in parallel when the distance between two consecutive fins is shorter than the size of the probe contacts. To minimize this first contribution, we use atomic force microscopy (AFM) to measure the lateral extent of the probe imprints and only focus on arrays where the fin distance is larger than the imprint. Second and most important of all, for very high fin resistances (e.g. narrow fins made of lowly doped material), current may significantly leak into the substrate [2,6]. This second contribution is investigated in two different manners. Since the impact of such parasitic resistances rises as the feature width decreases, we study the resistance-to-width correlation in fins with widths ranging from 20 nm to 10 μm. Also we investigate the resistances measured in the different available configurations (A, B and C) as their ratio offers valuable information on the dimensionality of the current path (one-dimensional in the trench and two-dimensional in the substrate) [4]. Our study concludes on recommendations targeting the accurate resistance measurement of sub-50-nm fins. [1] D. K. Schroder, Semiconductor material and device characterization, 3rd ed., Chap I, Wiley-Interscience (2006) [2] D.C. Worledge et al., Appl. Phys. Lett. 83, 84 (2003) ; D. Kjaer, et al., Meas. Sci. Technol. 26, 045602 (2015). [3] D. H. Petersen et al., J. Vac. Sci. Technol. B 28, C1C27 (2010); T. Clarysse, et al., Mater. Sci. and Eng. B 154, 24 (2008); T. Clarysse et al., J. Vac. Sci. Technol. B 28, C1C8 (2010) [4] J.D. Buron, et al., Nano Lett. 12, 5074 (2012); J.D. Buron, et al., Nano Lett. 14, 6348 (2014). [5] R. Lin, et al., Nanotechnology 15, 1363 (2004) ; [6] R. Lin et al., AIP Conf. Proceedings 1496, 175-178 (2012); C.L. Petersen, et al., RTP 2006 (IEEE NY, 2006), 153-157; T. Clarysse et al., Mater. Res. Soc. Symp. Proc. 912, 197 (2006).

A transformed analytical model for thermal noise of FinFET based on fringing field approximation**Project supported in part by the All India Council for Technical Education (AICTE).

This paper delineates the effect of nonplanar structure of FinFETs on noise performance. We demonstrate the thermal noise analytical model that has been inferred by taking into account the presence of an additional inverted region in the extended (underlap) S/D region due to finite gate electrode thickness. Noise investigation includes the effects of source drain resistances which become significant as channel length becomes shorter. In this paper, we evaluate the additional noise caused by three dimensional (3-D) structure of the single fin device and then extended analysis of the multi-fin and multi-fingers structure. The addition of fringe field increases its minimum noise figure and noise resistance of approximately 1 dB and 100 Ω respectively and optimum admittance increases to 5.45 mƱ at 20 GHz for a device operating under saturation region. Hence, our transformed model plays a significant function in evaluation of accurate noise performance at circuit level.

Investigating the performance of SiGe embedded dual source p-FinFET architecture

In this work, a modified Fin shaped Field Effect Transistor (FinFET) structure has been proposed with dual SiGe embedded extended source regions. Comparative simulation studies with SiGe embedded source/drain conventional single Fin channel and dual Fin channel FinFET structure having similar device footprint area shows almost 3× and 1.5× improvement of drive current respectively and lower threshold voltage in the proposed architecture. The dual extended SiGe source regions and presence of Si drain in the vertical direction of the channel generate bi-axial channel stress which improves the channel charge density, which results in improvement in drive current significantly. Also it has been observed from various simulation studies that the separated gate regions increase the inversion current density in the channel which also leads to improvement of the device performance.

Review: HACLab Pittsburgh: Imagining the Modern

HACLab Pittsburgh: Imagining the Modern Heinz Architectural Center, Carnegie Museum of Art, Pittsburgh 12 September 2015–2 May 2016 Entering the exhibition HACLab Pittsburgh: Imagining the Modern , visitors were caught between two black-and-white photographs by Edward Massery. To the right was a photograph of the Civic Arena—the Igloo, as it was nicknamed by Pittsburghers—before it was torn down, rising in a luminous dome, its perfect curvature made even more beautiful by the stubborn verticality of other modernist buildings behind it (Figure 1). To the left was a photo of the Civic Arena halfway through demolition (Figure 2). Here the Igloo is reduced to a mere quadrant, which, while still rising majestically, now looks like a single fin of the Sydney Opera House marooned in downtown Pittsburgh. You might say that the rest of the exhibition lived, indeed thrived, in the uneasy tension between these twin photographs: the potential seduction of the grand architectural gesture foreclosed by the disenchantment with modernism; the boosterism of urban redevelopment shadowed by the shameful legacy of uprooted communities and cultural fragmentation; and the heroic rhetoric of Pittsburgh's Renaissance smacking of maudlin sloganeering. Figure 1 Edward R. Massery, Civic Arena from Wylie Avenue, 9.27.2011 , inkjet print (Carnegie Museum of Art, Pittsburgh; Purchase: Second Century Acquisition Fund. © Ed Massery). Figure 2 Edward R. Massery, Civic Arena Yields to the Pittsburgh Skyline, 3.6.2012 , inkjet print (Carnegie Museum of Art, Pittsburgh; Purchase: Second Century Acquisition Fund. © Ed Massery). The exhibition was the first of a series of …

배열회수 보일러 단일 휜튜브의 양력과 항력 변동에 따른 PSD 특성 연구

배열회수 보일러의 전열관군은 외부에 고온의 배기가스가 흐르면서 유동 유발 진동을 야기 시키며 배열회수 보일러의 전열관군에서 파손을 야기할 수 있어서 열교환기의 구조적 안정성을 위해 열교환기의 전열관군에서 유동 유발 진동 특성을 규명할 필요가 있다. 일반적인 열교환기 전열관군에서 유동 유발 진동에 관한 실험적 연구는 기존에 많이 진행되어 오고 있으며 단일 원관이나 전열관군의 원관들에서 유동 유발 진동에 대한 무차원 PSD(Power Spectral Density) 함수를 무차원 주파수인 Strouhal 수, fD/U의 함수로 도출된 실험적 결과들이 도출되어 있다. 본 연구는 배열회수 보일러에 사용하는 휜튜브 전열관군에서 유동 유발 진동 특성을 규명하는 것을 목적으로 한다. 이러한 것을 위해 단일 휜튜브에서 비정상 상태 유동해석을 수행하여 주기적인 와동 발생 특성과 단일 휜튜브에서의 양력과 항력 변화 특성을 살펴보았다. 또한 단일 휜튜브에서 양력과 항력 변동 특성으로부터 유동 유발 진동에 따른 PSD 특성 결과를 도출하여 기존에 단순 원관에서 이루어졌던 연구들과 비교를 통해 단일 휜튜브 주위의 PSD 특성을 정립하였다. Heat exchanger tube array in a heat recovery steam generator is exposed to the hot exhaust gas flow and it could cause the flow induced vibration, which could damage the heat exchanger tube array. It is needed for the structural safe operation of the heat exchanger to establish the characteristics of flow induced vibration in the tube array. The researches for the flow induced vibration of typical heat exchangers have been conducted by using single cicular tube or circular tube array and the nondimensional PSD(Power Spectral Density) function with the Strouhal number, fD/U, had been derived by experimental method. From the present study, the basis for the application of flow induced vibration to the heat recovery steam generator tube array would be prepared. For the previous mentioned purpose, the present CFD analysis introduced a single fin tube and calculated with the unsteady laminar flow over the single fin tube. The characteristics of vortex shedding and lift and drag fluctuation over the fin tube was investigated. The derived nondimensional lift PSD was compared with the results of the previous experimental studies and the characteristics of lift and drag PSD over a single fin tube was established from the present CFD study.