Thin Vertical Wall Research Articles

Experimental investigation on turning Inconel 713C under different cooling conditions using a new honeycomb-textured tool

ABSTRACT Tool surface texturing is a new sustainable method for machining hard-to-machine materials. The present study focuses on the new honeycomb texture (mimic of bee’s honeycombs) containing hexagons forming between thin vertical walls. The important novelty in this work is the cutting performance of honeycomb texture on Inconel 713C was examined under cutting parameters and different cooling conditions: dry untextured (T1), dry textured (T2) tool, impregnated solid lubricant (hexagonal boron nitride (hBN)) textured tool (T3), MQL (coconut oil) with textured tool (T4), and NMQL (0.20 wt.% hBN + coconut oil) with textured tool (T5). Compared to plain tools, NMQL to honeycomb texture reduced flank wear by 53.2%, roughness by 43.2%, turning force by 27%, and cutting temperature by 47.7%. Honeycomb texture with MQL (T4) and NMQL (T5) reduces flank surface Ni element diffusion during turning. Nanofluid-textured inserts (T5) demonstrated higher shear angles, lower chip curl diameter, and shorter tool-chip contact length than other conditions.

Encapsulation of sodium silicate to attain on demand buildability enhancement in concrete 3D printing

This study investigates the encapsulation of a buildability enhancing additive using a phase change material (PCM) as a thermo-responsive additive for concrete 3D printing. The encapsulated additive is mixed with printable mixes and activated at the print head. The printhead activation via the heating process dissolves the capsules and releases the buildability enhancing additive to attain the required rheological properties for printing. A sodium silicate-based set accelerator was used as the buildability enhancing additive and encapsulated using a paraffinic PCM. The comprehensive experimental study was conducted to understand the effect of encapsulated sodium silicate on the pumpability of concrete followed by buildability after print head heating. It was demonstrated that the smaller addition of encapsulated sodium silicate (5 %) followed by print head activation resulted in the static yield strength (SYS) of 122 kPa after 25 min of placement compared to 8 kPa observed for mixes containing nanoclay as a thixotropic additive. Furthermore, the dissolution process of sodium silicate was assessed via an analytical method using optical technology to determine the diffusion coefficient of sodium silicate in the printable concrete. The proposed method was validated by printing a thin vertical wall with the optimised mix design developed during the study. Consequently, the mechanical properties of the printed specimen were investigated. The mixes containing the encapsulated additive showed a compressive strength reduction by up to 47 % for mould cast and 3D printed specimens and this was correlated to increased porosity of the mixes.

Nomex Material and Nomex Honeycomb Structure Honey Comb Structure in Electre Method

This paper presents detailed experimental results. Paper A primer on honeycomb mechanical modelling architectures Studies always focus on stable conditions paying; Some random innovative honeycomb Based paper assembly structures their They have excellent mechanical performance and are specific Significant in recent years due to operations have received attention. The geometrically varying feature of honeycomb structures is the hollow cells that form between the thin vertical walls. The hexagonal shape of the actual honeycomb is usually the strongest shape. Advantages of Honeycomb Mixtures Exceptional strength to weight ratio. High hardness fire and fungus resistant honeycomb structures: It is found in soils ranging from 0.02 mm to 0.002 mm. ELECTRE (Elimination and Choux Traduisant La Reality - Elimination and Choice expresses reality) methods from recruitment to many real-world decision-making there are problems widely used. Transportation and more. Theoretical research on the fundamentals of electret methods is also active at this time. Alternative: Length of structure, Width of structure, Total thickness of structure, Hexagonal core height, Upper and lower sheet, longitudinal tension strength. Evaluation Preference: Population size, Number of generation, Crossover probability, Crossover distribution index. From the result it is seen that data flow testing is got the first rank where as is the Crossover distribution index is having the lowest rank.

Influence of thermal gravitational-capillary convection on temperature fields in a thin wall

The development of convective flow in a layer of ethyl alcohol when heating one of the vertical walls of a rectangular cavity was investigated experimentally. Thermal films were obtained, whose processing allowed plotting in time the distribution of temperature and temperature gradients on the free surface of the liquid layer and the opposite thin vertical wall of the cavity after the flow of heated liquid on it.

Dependence of the temperature fields of a thin vertical wall on the intensity of the oncoming flow of a heated liquid

The processes of the development of free convection of ethanol in the regimes of heating the vertical wall of a rectangular cavity are experimentally investigated. The hydrodynamics in the cavity and the dependence of the temperature field on the opposite thin vertical wall are studied. Non-stationary temperature fields on a thin wall were measured with a thermal imager. The experiments were carried out at different densities of heat fluxes on the heater and at a discrete set of heights of the liquid layers.

Experimental studies of the evolution of non-stationary natural convective boundary layers at different heat flux densities on a vertical wall

The evolution of convective flow in a layer of ethyl alcohol with a free surface after sudden heating of one of the vertical walls of a rectangular cavity is experimentally studied. The evolution of a non-stationary hydrodynamic boundary layer on a heated vertical wall in time is studied using digital video recording and computer processing of video films. The evolution of the flow along the free surface of the liquid layer is investigated. Using a thermal imager, the time evolution of the temperature field on a thin metal vertical wall after the flow of a heated liquid is investigated.

Wave attenuation by multiple thin vertical porous walls in water of uniform finite depth

The analysis for wave attenuation by multiple thin porous walls submerged in water of uniform finite depth is carried out under the acceptance of linear theory of water waves. Two different types of barrier configurations are considered, namely partially immersed walls and bottom-standing walls. A set of coupled Fredholm-type integral equations are obtained for the boundary value problem by employing Havelock's inversion formulae and continuity of water wave potential across the gap below or above the walls. The methodology adopted to solve these integral equations is multi-term Galerkin's approximation with Chebychev's polynomials as a set of basis functions multiplied by suitable weights. Also, the square-root singularity of fluid velocity at the edge of the porous walls is precisely handled. The numerical results are depicted for reflection and transmission coefficients, dissipation of wave energy and dynamic wave force against wavenumber for different parametric values involving in the barrier configurations. This theory demonstrates that the dynamic wave forces exerted on the porous walls are reduced significantly as the magnitude of the porous effect parameter is increased. The present study is ratified with the existing results in the literature of water waves for a single as well as double rigid barriers and single porous barrier.

Improved model and experimental validation of deformation in fused filament fabrication of polylactic acid

RepRaps (self-replicating rapid prototypers), which 3D print objects using fused filament fabrication (FFF), have evolved rapidly since their open-source introduction. These 3D printers have primarily been limited to desktop sizes of volumes of ~ 8000 cm3, which has limited the attention of the scientific community to investigating deformation of common thermoplastics such as polylactic acid (PLA) used in FFF printing. The only existing physically relevant deformation model was expanded here to use a physics-based temperature gradient instead of a step function. This was necessary to generalize the model to 3D printing in a room temperature environment without a heated chamber. The thermal equation was calibrated using thermal measurements and validated by measuring curvatures in printed objects. The results confirm that this is a valid model for predicting warpage of thin vertical walls of PLA. In addition, the effect of annealing was examined. It was found that at a temperature of 50 °C, no shrinkage or crystallization takes place, but at 90 °C the PLA rapidly crystallizes to around 20% crystallinity. This indicates that heated bed temperatures should be maintained at 50 °C or lower to avoid print failure (premature substrate release) with PLA. At 90 °C, the annealing is accompanied by a 5% size decrease in both horizontal dimensions, but an 8% increase in the vertical dimension. Thus, the volume decreased by only 3%. This observation may lead to potential methods of improving slicing of printing large PLA objects with FFF.

On the possibility of steady-state solutions application to describe a thermal state of parts fabricated by selective laser sintering

The temperature distribution during selective laser sintering of a thin vertical stainless-steel wall has been simulated. The object is grown by successive deposition and laser melting of powder layers. An adjoint problem, including calculation of temperature in the part and the surrounding operating region, has been solved for different manufacturingprocess parameters within the plane statement based on two different approaches. The first approach considers transient heat conduction problem for a layer-by-layer grown body. The height of the calculation domain increases at each calculation step due to the addition of a new powder layer and a short-term laser treatment is applied to the layer region. The duration of one calculation step is determined by the time between two laser passes. The temperature distribution found at each step is used as the initial conditions for calculations at the next step. The thermal state achieved by the object under consideration after 500 calculation steps (i.e., after deposition and melting of 500 layers) is compared with a corresponding solution to the quasi-steady-state problem, which is found for a final geometry of the part, provided that a constant time-averaged heat flux is set to be supplied to the synthesis region. By example of the simple geometry under consideration, a quasi-steady-state solution can provide a fairly good estimate of the macroscopic thermal state of the synthesized part.

Scattering of interface wave by bottom undulations in the presence of thin submerged vertical wall with a gap

In this paper, the problem of interface wave scattering by bottom undulations in the presence of a thin submerged vertical wall with a gap is investigated. The thin vertical wall with a gap is submerged in a lower fluid of finite depth with bottom undulations and the upper fluid is of infinite height separated by a common interface. In the method of solution, we use a simplified perturbation analysis and suitable applications of Green’s integral theorem in the two fluid regions produce first-order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom undulations and solution of the scattering problem involving a submerged vertical wall present in the lower fluid of uniform finite depth. For sinusoidal bottom undulations, the first-order transmission coefficient vanishes identically. The corresponding first-order reflection coefficient is computed numerically by solving the zero-order reflection coefficient and a suitable application of multi-term Galerkin approximations. The numerical results of the zero-order and first-order reflection coefficients are depicted graphically against the wave number in a number of figures. An oscillatory nature is observed of first-order reflection coefficient due to multiple interactions of the incident wave with bottom undulations, the edges of the submerged wall and the interface. The first-order reflection coefficient has a peak value for some particular value of the ratio of the incident wavelength and the bottom wavelength. The presence of the upper fluid has some significant effect on the reflection coefficients.

Electrochemical characteristics of nanostructured silicon anodes for lithium-ion batteries

High-aspect periodic structures with thin vertical walls are studied as regards their applicability as negative electrodes of lithium-ion batteries. The nanostructures are fabricated from single-crystal silicon using photolithography, electrochemical anodization, and subsequent anisotropic shaping. The capacity per unit of the visible surface area of the electrode and the specific internal surface area are compared for structures of varied architecture: 1D (wires), 2D (zigzag walls), and 3D structures (walls forming a grid). Main attention is given to testing the endurance of anodes based on zigzag and grid structures, performed by galvanostatic cycling in half-cells with a lithium counter electrode. The influence exerted by the geometric parameters of the structures and by the testing mode on the degradation rate is determined. It is shown that the limiting factor of the lithiation and delithiation processes is diffusion. The endurance of an electrode dramatically increases when the charging capacity is limited to ∼1000 mA h/g. In this case, nanostructures with 300-nm-thick walls, which underwent cyclic testing at a rate of 0.36C, retain a constant discharge capacity and a Coulomb efficiency close to 100% for more than 1000 cycles.

Dovetail Tip: A New Approach for Low-Threshold Vacuum Nanoelectronics

An innovative approach for the fabrication of low-threshold, nanoscale field-emitter cathodes and arrays is proposed. By shaping a titanium cathode as dovetail geometry and using a thin vertical wall of high-permittivity dielectric, Si3N4, to isolate the tip from the gate, the electric field intensity near the tip edges is strongly increased, and a turn-ON voltage in the range of a few volts is predicted numerically and observed experimentally. The resulting cathode structure is compact, self-aligned to the vacuum cavity and is fabricated through the standard silicon fabrication processes. Besides, unlike all existing approaches, vacuum is achieved at the wafer level and not at the package level, thereby reducing fabrication costs. Measurements on a first prototyped array of $5\times 4$ diode-connected parallel devices with a silicon area of $5~\mu \text {m}\times 4~\mu \text{m}$ , confirm Fowler–Nordheim emission with a 2 V turn-ON voltage, while displaying a total emission current of 25 $\mu \text{A}$ at a gate-cathode bias of 20 V.

Study of Dimensional Repeatability and Fatigue Life for Deformation Machining Bending Mode

Deformation machining (DM) is a hybrid process which combines two emerging manufacturing processes, machining of thin structures and single-point incremental forming (SPIF). This hybrid process enables the creation of structures that have geometries that would be difficult or impossible to create using any either process alone. A comprehensive study of DM bending mode components has been carried out in this paper by studying their dimensional repeatability and fatigue life and comparing these with similar components fabricated with sheet metal. Experimental studies have been performed for part features created by the DM “bending mode” process, in which a thin vertical wall is machined on the part, and then incrementally bent with a single-point forming tool. The dimensional repeatability of DM components is compared with sheet metal components made by single-point incremental forming and conventional bending in a press brake [Agrawal et al., 2010, “Comparison of Dimensional Repeatability of Deformation Machined Components With Sheet Metal Components,” North American Manufacturing Research Conference, NAMRC 38, Transactions of NAMRI/SME, Vol. 38, pp. 571–576]. The results of this study indicate that the DM process is not capable of holding tolerances as tight as a standard milling process. This may be due to local variations in material properties that influence the yield strength and resulting springback. However, thin components created by DM are more repeatable than similar components created from sheet metal using SPIF, but less repeatable than components created by conventional bending of sheet metal. The second objective of the present work is to investigate whether components fabricated using the DM process can be considered for fatigue critical applications [Megahed et al., 1996, “Low-Cycle Fatigue in Rotating Cantilever Under Bending I: Theoretical Analysis,” Int. J. Fatigue, 18(6), pp. 401–412; Khalid et al., 2007, “Bending Fatigue Behavior of Hybrid Aluminum/Composite Drive Shafts,” Mater. Des., 28, pp. 329–334]. Studies were performed to experimentally compare the fatigue life of components fabricated by DM process with sheet metal components made by single-point incremental forming and conventional bending. Results of the study indicate that sheet metal SPIF components under the present loading conditions have significantly longer fatigue life of approximately 3900–5500 cycles, compared to DM and sheet metal conventionally bent components with approximately equal fatigue life of 2200–3900 cycles.

F222001 細胞機能計測マイクロデバイスの研究開発

In the field of re-generative medicine, understanding the function of cell and tissue is key issue. To understand the cell and tissue functions, many micro devices, called Micro TAS( Total analysis systems) are proposed and used in the field of medicine and life science research. We are studying the function of the pancreas islet. Pancreas islet is composed of mainly p cell and a cell,. The function of those cells are opposite. The (3 cell secrete the insulin to decrease the concentration of blood sure and a cell secrete the Glucagon to increase it. We have developed two types of novel microfluidic device for space- and time-resolved visualization of intracellular events when a cell surface is partially exposed to external stimuli. First device is horizontal type to measure the insulin secretion of p cell. And second device is vertical type to measure the cell -cell communication. Both devices, fabricated using 3D rotational inclined UV lithography of photoresist SU-8, consists of a cell-containing chamber and a flow channel separated by a thin vertical wall having a lateral micrometer aperture smaller than a cell, see Fig.l. A cell is first immobilized on the orifice by suction from the flow channel using a syringe pump, and a chemical stimulant is then fed to the channel so that only the cell surface bounded by the aperture is subjected to the stimulus without leakage to other part of the cell surface. The first demonstration, see Fig.2, shows the fabricated orifice to immobilize the cell. As an experimental demonstration of the device, The subsequent lateral signal propagation inside the cell can be visualized using high-speed fluorescence confocal microscopy. 2-NBDG (fluorescence glucose analog) intake into a mouse insulinoma cell, MIN6m9, was visualized in 4D resolution. The structure of the second device to measure the cell- cell communication is shown in Fig.3. The cell are immobilized on the micro orifice and the target cell is stimulated by the high glucose solution by the micro cannel which is designed only target cell is stimulated. The micro-channels and micro-orifices are simultaneously fabricated by using inclined UV lithography. And the cytosolic Ca2+ concentration of immobilized cells is measured.

Localized substance delivery to single cell and 4D imaging of its uptake using a flow channel with a lateral aperture

We have developed a novel microfluidic device for space- and time-resolved (4D) visualization of intracellular events when a cell surface is partially exposed to external stimuli. The device, fabricated using 3D rotational inclined UV lithography of photoresist SU-8, consists of a cell-containing chamber and a flow channel separated by a thin vertical wall having a lateral micrometer aperture smaller than a cell. A cell is first immobilized on the aperture by suction from the flow channel using a syringe pump, and a chemical stimulant is then fed to the channel so that only the cell surface bounded by the aperture is subjected to the stimulus without leakage to other part of the cell surface. The subsequent lateral signal propagation inside the cell can be visualized using high-speed fluorescence confocal microscopy. As an experimental demonstration of the device, 2-NBDG (fluorescence glucose analog) intake into a mouse insulinoma cell, MIN6m9, was visualized in 4D resolution.

Effect of nonstationary thermal gravitation-capillary convection on temperature distribution in a thin vertical wall

Time dependences of temperature distributions in a thin metal wall were studied experimentally under two conditions of convective heat transfer in a tank model. In the first case, the vertical working wall was heated from within due to a convective heat flux from the opposite wall heated monotonously, and it was cooled due to heat transfer to the ambient medium. Dependence of the temperature field on a thin wall at the stage of convective flow development was retraced with the help of the thermographic camera and thermocouple sensors. In the second case, the tank wall was heated uniformly by IR radiation from the outside, and non-stationary convective flow and volumetric liquid heating were formed inside. Time dependence of temperature distribution over the wall height is studied. It is shown that the flow structure and convective heat transfer in a fuel layer with free boundary are subjected not only to the buoyancy force, but also to the thermocapillary effect. The local features of the flow affect temperature distribution in a thin wall.

Porous Effect Parameter of Thin Permeable Plates

The present paper aims at getting the porous effect parameter G of a thin permeable wall. The reflection and transmission coefficients of a thin vertical porous wall with different porous shapes and porosities are obtained by a physical model experiment. The reflection coefficient and total horizontal wave load on a perforated caisson are also obtained by another experiment. Analytical solutions of wave interaction with these two vertical porous breakwaters are introduced. The reflection and transmission coefficients between predictions and experimental results of authors' and four other researchers' are compared. By comparisons, the estimate methods of the linearized resistance coefficient f and the inertial effect coefficient s of the permeable plate are recommended. Following the formula of Yu [1995], the values of G are calculated by f and s. A complete estimate method of porous effect parameter G is presented, which consists of the formula of Yu [1995] and the present experimental formula. The estimate method of G is validated by comparing the predicted values of the total horizontal wave loads on the perforated caisson with the experimental results.

Tidal generation of internal waves from a periodic array of steep ridges

The generation of internal gravity waves by an oscillatory tidal flow over a periodic array of thin vertical walls is calculated analytically. For small values of the non-dimensional height $B=2\pi H\!N/L\omega$ , the radiated power per wall is the same as for a single thin wall, and proportional to $B^2$ , in agreement with the linear scaling. (Here $H$ is the wall height, $N$ the buoyancy frequency, $L$ the wall spacing, and $\omega$ the tidal frequency.) The radiated power is periodic in $B$ with period $2\pi$ . It diverges logarithmically for $B=(1+2n)\pi$ , and vanishes for $B=2n\pi$ .

Scattering of water waves by a submerged thin vertical wall with a gap

AbstractA train of surface water waves normally incident on a thin vertical wall completely submerged in deep water and having a gap, experiences reflection by the wall and transmission through the gaps above and in the wall. Using Havelock's expansion of water wave potential, two different integral equation formulations of the problem are presented. While the first formulation involves multiple integral equations which are solved here by reducing them to a singular integral equation with Cauchy kernel in a double interval, the second formulation involves a first-kind singular integral equation in a double interval with a combination of logarithmic and Cauchy kernel, the solution of which is obtained by utilizing the solution of a singular integral equation with Cauchy kernel in (0, ∞) and also in a double interval. The reflection coefficient is evaluated by both the methods.

Oblique wave scattering by submerged thin wall with gap in finite-depth water

The problem of oblique wave scattering by a submerged thin vertical wall with a gap in finite-depth water and its modification when another identical wall is introduced, are investigated in this paper. The techniques of both one-term and multiterm Galerkin approximations have been utilized in the mathematical analysis. The multi-term approximations in terms of appropriate Chebyshev polynomials provide extremely accurate numerical estimates for the reflection coefficient. The reflection coefficient is depicted graphically for a number of geometries. It is found that by the introduction of another identical wall, there occurs zero reflection for certain wave numbers. This may have some bearings on the modelling of a breakwater.