Miracle-dz/UniFAR-FTUs huggingface dataset:
Comparison of the 1D and 2D calculation models used for determination of the heat transfer coefficient during flow boiling heat transfer in a minichannel

The paper discusses the results of the flow boiling heat transfer in a vertical minichannel with rectangular cross-section. The heating element for FC-72 flowing in the minichannel is a thin plate. Infrared thermography is used to determine changes in the temperature on its outer side. The aim of thecalculation is to determine the heat transfer coefficient using 1D and 2D calculation models. Local values of heat transfer coefficient on the surface between the heated plate and boiling fluid are calculated from the Newton`s and Fourier`s laws. In 2D model the plate temperature distribution is obtained by solving the inverse heat conduction problem. The governing equation is solved by means of two methods: the non-continuous Trefftz method and the Beck method. The results are presented as plate temperature and heat transfer coefficient calculated using 1D and 2D models as a function of the distance fromthe minichannel inlet. The analysis of the results revealed that the values and distributions of the heat transfer coefficient calculated by means of both models were similar. This suggests that all mentioned methods are interchangeable.
Inverted vibrational distributions from N2 recombination at Ru(001): Evidence for a metastable molecular chemisorption well

We have measured translational and internal state distributions for N2 desorbed from a Ru(001) surface following NH3 cracking at 900 K. Nitrogen is formed with a vibrational population inversion, P(v=1)/P(v=0)=1.4, but a subthermal rotational energy release, Trot(v=0)=630 K. The translational energy distributions show a peak at low energy with a tail extending up to ∼2 eV and a mean energy release of 0.62 eV for N2(v=0) and 0.61 eV for (v=1). The product state distributions indicate a preferential energy release into the N2 stretching coordinate with a relatively weak N2–surface repulsion. Density functional calculations for N2 dissociation on Ru(001) and Cu(111) have been performed to compare the shape of the potentials in the N2 stretching (d) and translational (Z) coordinates. These reveal a sharp curvature of the surface for Ru, the energy release occurring close to the surface over a narrow range of Z. We suggest that this behavior is the result of the presence of a metastable molecular state, bound .
First-Principles Study of Gas Molecule Adsorption on C-doped Zigzag Phosphorene Nanoribbons

Phosphorene, due to its large surface-to-volume ratio and high chemical activity, shows potential application for gas sensing. In order to explore its sensing performance, we have performed the first-principles calculations based on density functional theory (DFT) to investigate the perfect and C-doped zigzag phosphorene nanoribbons (C-ZPNRs) with a series of small gas molecules (NH3, NO, NO2, H2, O2, CO, and CO2) adsorbed. The calculated results show that NH3, CO2, O2 gas molecules have relatively larger adsorption energies than other gas molecules, indicating that phosphorene is more sensitive to these gas molecules. For C-ZPNRs configuration, the adsorption energy of NO and NO2 increase and that of other gas molecules decrease. Interestingly, the adsorption energy of hydrogen is −0.229 eV, which may be suitable for hydrogen storage. It is hoped that ZPNRs may be a good sensor for (NH3, CO2 and O2) and C-ZPNRs may be useful for H2 storage.
A Novel InGaP/InGaAs/GaAs Double -Doped pHEMT With Camel-Like Gate Structure

This letter reports a novel InGaP/InGaAs/GaAs double delta-doped pseudomorphic high-electron mobility tran- sistor (pHEMT) with n -GaAs/p -InGaP/n-InGaP camel-like gate structure grown by MOCVD. Due to the p-n depletion from the p -InGaP gate to the channel region and the presence of at InGaP/InGaAs heterostructure, the turn-on voltage of gate is larger than 1.7 V. For a 1 100- m device, the experimental results show an extrinsic transconductance of 107 mS/mm and a saturation current density of 850 mA/mm. Significantly, an extremely broad gate voltage swing larger than 6 V with above 80% maximum is obtained. Furthermore, the unit current cut-off frequency and maximum oscillation frequency are up to 20 and 32 GHz, respectively. The excellent device performance provides a promise for linear and large signal amplifiers and high-frequency circuit applications.
Optimization of Fast Fashion Retail Supply Chain Processes: Overall Literature Review and Future Research Challenges

Fast fashion trends are changing in nonstop. Brands are consequently faced to big challenges. Processes must be fluent, while costs must be optimized within all the constraints. This article is a literature review, about the fast fashion process engineering challenges, from production to retail. We explore a review analysis of the main problematic nodes, of the whole chain, that retailers focus on to improve their productivity and profit. We examine the literature review of solutions proposed to these problems. Finally we propose the untapped fields, and the potential research scopes to work on in future.
A novel plasma source for surface chemical patterning and spatial control of cell adhesion.

The aim of this work was to develop and characterise a plasma source, which could be used to modify polymeric surfaces and incorporate well-defined regions of controlled chemistry. A novel plasma treatment system in which the ion energy and flux at the substrate can be independently controlled was developed. Argon plasma was separated into two regions with stainless steel meshes. The ion energy and flux in the substrate processing region was manipulated by applying an electrical bias to these meshes. This 'tailored' plasma was used to investigate the relative contributions of ions and vacuum ultra-violet (VUV) photons in the plasma treatment of polystyrene (PS). The level of surface modification induced by the plasma treatment was ascertained by X-ray photoelectron spectroscopy (XPS). Isolation of the VUV component by use of the biased mesh system revealed that in this system, these photons were the primary species causing oxygen incorporation into the PS surface. The modified PS was successfully employed as a culture substrate for bone marrow stromal cells (BMSC). By use of transmission electron microscopy (TEM) grids placed on the PS surface during exposure to the source, micron scale surface chemical patterns were produced. The pattern of hydrophilic and hydrophobic regions was visualised by condensing water onto the surface. On these substrates, bone marrow stromal cells (BMSC) formed patterns with features as small as 5 μm. The ability to independently control the ion energy and flux at the substrate has enabled the identification of the primary plasma species involved in surface modification of PS in this system. Combined with simple patterning technology, the novel plasma source has been used to produce well-defined micron scale chemical patterns on PS. The biological utility of such patterned substrates has been demonstrated by spatial control over cell attachment and spreading.
EFFECTIVE THERMOPHYSICAL PROPERTIES OF THERMAL INTERFACE MATERIALS: PART I DEFINITIONS AND MODELS

The conductivity of thermal interface materials are typically determined using procedures detailed in ASTM D 5470. The disadvantages of using these existing procedures for compliant materials are discussed along with a proposed new procedure for determining thermal conductivity and Young’s modulus. The new procedure, denoted as the Bulk Resistance Method, is based on experimentally determined thermal resistance data and an analytical model for thermal resistance in joints incorporating thermal interface materials. Two versions of the model are presented, the Simple Bulk Resistance Model, based on the interface material thickness prior to loading and a more precise version denoted as the General Bulk Resistance Model, that includes additional parameters such as surface characteristics and thermophysical properties of the contacting solids. Both methods can be used to predict material in situ thickness as a function of load. NOMENCLATURE A =a rea of contact ( m 2 )
Wetting translucency of graphene on plasmonic nanohole arrays

Graphene- a carbon allotrope with atoms arranged in monolayer 2D hexagonal lattice- exhibits wide range of applications in batteries, supercapacitors, solar cells, biosensing, light-emitting diodes, semi-conductors, materials composites, and coatings to name a few. Significant progress has been made to understand the electronic, mechanical, and optical characteristics of graphene. However, the wettability of graphene, which is important for surface modification and thermal/fluidic properties, is still not well understood. The level of transparency to van der Waals forces, chemical bonds, and electrostatic interactions between atoms and molecules on two sides of graphene single layer is partially known. Static contact angle between the edge of sessile drop and functionalized surface provides surface tension value based on Owens–Wendt model and is important for wettability studies. In this work, we investigate the surface energy of glass, silicon wafer, and plasmonic nano-hole arrays (Silver, Polymer and Gold) suspended with CVD grown and transferred single layer of graphene. Our experimental results demonstrate that graphene is wetting transparent in the case of silicon and wetting opaque when deposited on the glass. The plasmonic nanohole arrays (NHAs) fall in the partially wetting transparent category. On plasmonic NHAs, the surface energy value got reduced with the suspending single layer graphene compared to absence of graphene. These results showed that the underlying substrate does affect the wettability of graphene monolayer due to van der Waal hydrocarbon, metal-carbide, and silica-carbon bonding which tends to provide deeper understanding of the wetting dynamics. This study elucidates the mechanism of short-range forces between water-graphene-substrate which is important during the fabrication of adhesives and coatings with controlled fluidic and heating properties.
Experimental and numerical investigations of vibration due to flow through an orifice

High precision manufacturing machines often require extremely tight tolerances in their end products. Hence vibrations induced by flow within internal components such as an orifice, can cause deviations in measurements and defects in production. These vibrations caused due to orifices are a result of large pressure drops generated during flow separation resulting in pressure waves that propagate within the system interacting with other components. In this article vibrations resulting from orifice flows are comprehensively studied through a series of experiments and numerical simulation. The experiments performed involve pressure measurements with varying orifice diameters. The pressure signals obtained from the experiment are recorded and analysed with respect to their energy distribution. The study is further extended to analyse the effect of orifice diameters on pressure fluctuations, and in the process also observe and identify the phenomena of cavitation. To obtain a more detailed understanding of the flow and the underlying behaviour, a Large-Eddy Simulation (LES) of orifice flow is performed for a selected orifice. The LES results are validated using different databases involving previous studies and the experiments that have been performed. The LES results are analysed in detail with regards to the spectral characteristics of velocity and pressure fluctuations using mathematical tools such as Fourier Analysis. The results provide an insight on the flow development, energy distribution and power spectrum distribution in the flow
Time-Resolved Flow Field Analysis of Effusion Cooling System With Representative Swirling Main Flow

Film-cooling jets behavior in a combustor chamber is deeply affected by swirling flow interactions and unsteadiness; on the other hand, the jets behavior has a direct impact on different phenomena such as cooling capabilities and ignition. For these reasons, an in-depth characterization of the film-cooling flows in the presence of a swirling main flow and demands dedicated time-resolved analyses. The experimental setup consists of a nonreactive single-sector linear combustor simulator installed in an open-loop wind tunnel. It is equipped with a swirler and a multiperforated plate to simulate the effusion cooling system of the liner. The rig is scaled with respect to the engine configuration to increase spatial resolution and to reduce the characteristic frequencies of the unsteady phenomena. Time-resolved particle image velocimetry (TRPIV) was exploited for the investigation testing different values of liner pressure drop. In addition, numerical investigations were carried out to gain a deeper insight of the behavior highlighted by the experiments and to assess the capability of computational fluid dynamics (CFD) in predicting the flow physics. In this work, the stress-blended eddy simulation (SBES) approach implemented in ansys fluent was adopted. Oscillations of the jets and intermittent interactions of the mainstream with the wall of the liner and hence with the film development have been investigated in detail. The results demonstrate how an unsteady analysis of the flow structures that characterize the jets, the turbulent mixing of coolant flows, and the interaction between mainstream and cooling jets is strictly necessary to have a complete knowledge of the behavior of the coolant, which in turn affects combustor operability and life time.
High‐Purity Triggered Single‐Photon Emission from Symmetric Single InAs/InP Quantum Dots around the Telecom C‐Band Window

The authors demonstrate pure triggered single‐photon emission from quantum dots (QDs) around the telecommunication C‐band window, with characteristics preserved under non‐resonant excitation at saturation, that is, the highest possible, lifetime‐limited emission rates. The direct measurement of emission dynamics reveals photoluminescence decay times in the range of (1.7–1.8) ns corresponding to maximal photon generation rates exceeding 0.5 GHz. The measurements of the second‐order correlation function exhibit, for the best case, a lack of coincidences at zero time delay—no multiple photon events are registered within the experimental accuracy. This is achieved by exploiting a new class of low‐density and in‐plane symmetric InAs/InP QDs grown by molecular beam epitaxy on a distributed Bragg reflector, perfectly suitable for non‐classical light generation for quantum optics experiments and quantum‐secured fiber‐based optical communication schemes.
Application of Neural Network to Visual Inspection of Weld Bead

An example of application of neural network is introduced. The backpropagation (BP) model is applied to the weld bead visual inspection. The bead shape data are picked up from the actual weld bead and divided into three categories. The weight values of the connections which joint the units in the different layer of the neural network are formed through the learning process made by using these data for each category. As the result of the test, it is shown that the discrimination between the sound bead and the defect bead can be done properly if the selection of the network parameters and the learning process are made suitably.
Condition Number of Acoustic Infinite Element

Various shape function and weight function of infinite element are researched and summarized into eight methods, and then various infinite element methods can be summarized as general equation, the condition number of which can reflect merits of infinite method. Condition number of various methods versus frequency and the node number are calculated in this paper. Finally, most optimal infinite element method is summed up. The infinite element method [1-12] is among the most successful techniques used to solve boundary-value problems on unbounded domains and whose solutions satisfy some condition at infinity. Two ideas make the infinite element method attractive: the idea of partition and the idea of approximation. The partition idea covers unbounded domains by attaching infinite strips to finite element partitions of bounded domains. More mature versions of infinite element method involved the approximation idea. These ideas make it possible that the finite element/infinite element method yields significantly greater computational efficiency than other methods such as the boundary element method. There have been a large number of infinite element methods, in which some methods have obvious advantages and some methods have fewer advantages. However, there is less research literature about merits of various infinite element methods appear at home and abroad. Thus, condition number of matrix equation is applied to verify merits of various infinite methods in this paper.
Fabrication of porous fibers via electrospinning: strategies and applications

Abstract In this paper we review the literature on electrospinning of porous fibers of micron and nanoscale diameters. Selection of an appropriate polymer-solvent system can yield porous fibers due to phase separation, and different types of porosity are generated by different phase separation mechanisms. In comparison with porous polymeric fibers, production of porous inorganic fibers is much more complex: small molecules or atoms cannot be directly electrospun into continuous fibers and so polymer precursors are required and subsequently removed. Inorganic porous fibers can be generated based on a range of materials: carbon, silica and numerous metal oxides and mixed metal oxides. Some of the many applications of electrospun porous fibers are discussed: applications ranging from tissue engineering and drug delivery, to water treatment, sensors, photocatalysis and lithium-ion batteries.
Measuring the dislocation density of VT1-0 titanium alloys with different content of hydrogen by x-ray diffraction method

In this study, the distributions of dislocation density with hydrogen concentration in titanium VT1-0 were obtained. The samples with different hydrogen concentrations was carried out by using the Sieverts method. The dislocation densities were obtained by using the full width at height medium calculations from the XRD results of Gaussian approximation fitting. For accurate calculation of the dislocation density in titanium alloys, the double-line separation phenomenon of the XRD results and the variation of the Burgers vector in different lattice directions were considered. The phenomenon of the double-line separation is more evident when the diffraction angle 2θ is larger than 40°. The mean value of dislocation density for the different hydrogen concentrations is about 1013 ∼ 1014 m−2. Moreover, as the increases of hydrogen content in the titanium alloy, the dislocation density also increases.
How are Materials Actually Used in Classrooms? Towards a Systematic Evaluation of a Locally Published Coursebook Series for Young Learners in Turkey

i ACKNOWLEDGEMENTS . ii TABLE OF CONTENTS . iii LIST OF TABLES . viii LIST OF FIGURES . ix LIST OF APPENDICES . x LIST OF ABBREVIATIONS . xi CHAPTER 1: INTRODUCTION . 1 1.1. Background Information . 1 1.2. The Purpose and Significance of the Study . 3 1.3. Research Questions . 5 1.4. Outline of the Thesis . 6 CHAPTER 2: REVIEW OF LITERATURE . 8 2.
A Novel Method for Structure-Based Prediction of Ion Channel Conductance Properties

A rapid and easy-to-use method of predicting the conductance of an ion channel from its three-dimensional structure is presented. The method combines the pore dimensions of the channel as measured in the HOLE program with an Ohmic model of conductance. An empirically based correction factor is then applied. The method yielded good results for six experimental channel structures (none of which were included in the training set) with predictions accurate to within an average factor of 1.62 to the true values. The predictive r2 was equal to 0.90, which is indicative of a good predictive ability. The procedure is used to validate model structures of alamethicin and phospholamban. Two genuine predictions for the conductance of channels with known structure but without reported conductances are given. A modification of the procedure that calculates the expected results for the effect of the addition of nonelectrolyte polymers on conductance is set out. Results for a cholera toxin B-subunit crystal structure agree well with the measured values. The difficulty in interpreting such studies is discussed, with the conclusion that measurements on channels of known structure are required.
Supercapacitors with gate electrodes

SUPERCAPACITORS WITH GATE ELECTRODES by Tazima Selim Chowdhury A new approach to improve the capacitance of supercapacitors (SC) is proposed in this study. A typical SC is composed of an anode and a cathode; a separator in between them assures an unintentional discharge of the capacitor. The study focuses on a family of structured separators, either electronically active or passive which are called gates. An active structured separator layer has been fabricated and analyzed. The structured separator has characteristics of electrical diode and is fabricated out of functionalized carbon nanotubes (CNT). Improvement of the overall capacitance of SC, equipped with either active or passive structured separators demonstrated a large capacitance increase compared to SC which are interfaced with traditional separators. Cyclic voltammetry (CV), Chrono-potentiometry (charge-discharge, C-D) and Electrochemical Impedance Spectroscopy (EIS) are used to assess the electrochemical characteristics of these novel devices. Raman spectroscopy is used to assess the quality of the structured CNT. Scanning electron microscope determines the surface morphology and porosity of the films. Current-voltage measurement takes place to ensure non-linear characteristics of the fabricated active separator layer. CV demonstrates that aqueous based electrolyte supercapacitors (SC) does not exhibit reaction peaks. Chrono-potentiometry demonstrates an overall 5-10% larger capacitance then traditional counterparts. EIS exhibits an unusual reduction of the cell's equivalent series resistance (ESR). Additional capacitance increase can be achieved when the active structured separator is biased between -0.1 V to +0.1 V. The electrical energy, invested in a biased gate is fully captured as a stored energy. A similar study is performed by fabricating active separator interfacing with ionic liquid electrolyte. Active gates exhibit similar capacitance improvement even after many cycles of charge and discharge when they are interfaced with ionic liquid. SUPERCAPACITORS WITH GATE ELECTRODES by Tazima Selim Chowdhury A Dissertation Submitted to the Faculty of New Jersey Institute of Technology in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Electrical Engineering Helen and John C. Hartmann Department of Electrical and Computer Engineering