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Search results for: TRAPEZOIDAL SHEETING
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Multiple access in ad-hoc wireless LANs with noncooperative stations
PublicationA class of contention-type MAC protocols (e.g., CSMA/CA) relies on random deferment of packet transmission, and subsumes a deferment selection strategy and a scheduling policy that determines the winner of each contention cycle. This paper examines contention-type protocols in a noncooperative an ad-hoc wireless LAN setting, where a number of stations self-optimise their strategies to obtain a more-than-fair bandwidth share. Two...
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Induction Assisted Hybrid Friction Stir Welding of Dissimilar Materials AA5052 Aluminium Alloy and X12Cr13 Stainless Steel
PublicationThis research aimed to study the induction in-situ heated hybrid friction stir welding (IAFSW) method to join AA5052 aluminium alloy with X12Cr13 stainless steel (SS) to enhance joint strength. The potency of this method on the mechanical properties and microstructural characterizations were also investigated. The results show that the transverse tensile strength gained was 94% of the AA5052 base metal that is 229.5 MPa. This superior...
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Energy policy and the role of bioenergy in Poland
PublicationPrzedstawiono sytuacje energetyczną kraju. Omówiono poszczególne sektory wytwarzania energii oraz zapotrzebowania na energię i paliwa. Omówiono przekształcenia sektorów energetycznych w Polsce na przestrzeni lat 1990-2002. Na tym tle przedstawiono techniczne, ekonomiczne, społeczne i prawne aspekty rozwoju energetyki źródeł odnawialnych a w szczególności opartych o bioenergię. Przedstawiono wnioski dla Polski płynące z dotychczasowych...
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Investigation of Microbes in the Stratosphere – Stardust Project
PublicationThe stratospheric microbiota has been investigated many times using the methods of classical microbiology. In this research a few modern methods, including NGS sequencing and multiple displacement amplification of DNA, were in use. The analysis of metagenome helped to determine the content of various species of bacteria in the sample collected in the stratosphere by a hydrogen-filled balloon holding...
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Thriving in multicultural workplace
PublicationThriving at work is defined as the psychological state that links both a sense of vitality and learning. The vitality component of thriving may be seen as positive energy, while learning enhances a sense of competence and efficacy. Thriving sheds new light on individual psychological functioning and the experience of growth in the work context. Thriving at work promotes growth through playing an active role in interaction with...
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Testing Students’ Entrepreneurial Self-Efficacy as an Early Predictor of Entrepreneurial Activities. Evidence From the SEAS Project
PublicationOver the last forty years, since Bandura (1977) introduced the concept of self-efficacy, there have been a constantly growing number of research publications using this concept. Its early development resulted in the creation of a new construct of entrepreneurial self-efficacy (ESE) proposed for the first time by (Chen et al. 1998). Since then, many different groups of research concerning ESE have emerged - one of them is the study...
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Acid-aided epoxy-amine curing reaction as reflected in epoxy/Fe3O4 nanocomposites: Chemistry, mechanism, and fracture behavior
PublicationThis work seeks to answer the question whether or not the presence of acid functional groups accelerate epoxyamine curing reaction. Epoxy/Fe3O4 nanocomposite was considered as a case, where discussions are based on chemistry, mechanism behind curing reactions and fracture behavior influenced by acid assistance to crosslinking. Fe3O4 magnetic nanoparticles (MNPs) with nanosilica decorative layer (B-MNP) were synthesized and subsequently...
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Edible black ant Smith (Carebara vidua) as human food – A systematic review
PublicationMeeting food security is one of the major global challenges to ensure sufficient supply of food for current and future generations, considering increasing population growth and climate change issues. Consequently, the consumption of edible insects as an alternative food source has recently gained global attention for combating global food insecurity. The present review aims to provide information on the recent progress in consumption...
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Effect of Surface Treatment of Halloysite Nanotubes (HNTs) on the Kinetics of Epoxy Resin Cure with Amines
PublicationThe epoxy/clay nanocomposites have been extensively considered over years because of their low cost and excellent performance. Halloysite nanotubes (HNTs) are unique 1D natural nanofillers with a hollow tubular shape and high aspect ratio. To tackle poor dispersion of the pristine halloysite (P-HNT) in the epoxy matrix, alkali surface-treated HNT (A-HNT) and epoxy silane functionalized HNT (F-HNT) were developed and cured with...
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Visual Object Tracking System Employing Fixed and PTZ Cameras
PublicationThe paper presents a video monitoring system utilizing fixed and PTZ cameras for tracking of moving objects. First type of camera provides image for background modelling, being employed for foreground objects localization. Estimated objects locations are then utilised for steering of PTZ cameras when observing targeted objects with high close-ups. Objects are classified into several classes, then basic event detection is being...
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Resonant ultrasonic spectroscopy in high-voltage varistor spectroscopy
PublicationResonant spectroscopy is an effective non-destructive testing method focused on defects in tested objects. The testing procedure, based on the resonant pattern, allows rejection of the tested samples with defects which do not fit the pattern. A sweeping frequency method has been used to measure the spectrum of resonances in high-voltage varistors. As a result we can observe resonances that depend directly on inhomogeneity of the...
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Adhesive compliance effect in mode I separation:Profilometry approach
PublicationThe effect of adhesive compliance on the deflection of a loaded, bonded beam was studied using laser profilometry. Experimental data obtained were compared with both Euler-Bernoulli (encastré) and Winkler (one parameter elastic foundation) models. A third, analytical, 2D model, based on shear within the adhesive layer (two parameter elastic foundation), was introduced. Finite element analysis (FEA) was also used to study the effect...
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Trajectory planning for Service Ship during emergency STS transfer operation
PublicationIn this paper trajectory for approaching during emergency STS transfer operation with oil spill is considered as a sequence of navigation manoeuvres in specific navigational environment. The designed way points - ship positions and speed are determined as reference values to support navigator in decision making during steering and to mitigate the risk of collision which mostly results from exceeding the speed limit of approaching....
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Energy efficient beam control for 5G antennas
PublicationThe rapid development of 5G and beyond systems demands improvement in communication speed, latency and safety to maintain the required quality of service. This paper presents an overview of different concepts of energy-efficient antenna systems, which offer beam-shaping and beam-steering functionalities, that enhance connectivity performance and can be used in 5G applications. Different designs for 5.9 GHz, 39 GHz and 60 GHz frequency...
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Constructive Controllability for Incompressible Vector Fields
PublicationWe give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen...
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On Radar DoA Estimation and Tilted Rotating Electronically Scanned Arrays
PublicationWe consider DoA estimation in a monopulse radar system employing a tilted rotating array. We investigate the case of nonzero steering angles, in which case the mapping between the target’s azimuth and elevation in the global coordinate system and their counterparts in the array local coordinate system becomes increasingly nonlinear and coupled. Since estimating the azimuth using coherently integrated signals might be difficult because...
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Nuclear power plant as a source of electrical energy and heat
PublicationIn this paper certain issues concerning usage of nuclear power plants as sources of not only electric power but also thermal energy will be discussed. For such a solution appeals most of all the need to limit harmful emissions of gases (including CO2) and ashes, which come from the process of burning fossil fuels, as well as the raising demand for network heat and chill. Additionally combined heat and power production brings measurable...
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Zachowania przedsiębiorcze a otoczenie instytucjonalne - mechanizmy
PublicationIn this paper the ways in which entrepreneurial behaviour is manifested in insti-tutional contexts of different quality is presented. Taken the assumption of Baumol that the supply of entrepreneurs in each economy is constant, and that there are changes in the share of productive and unproductive entrepreneurship in this supply, it is emphasized that the quality of institutional framework determines the outco-mes of entrepreneurship...
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ENISA Study: Challenges in Securing Industrial Control Systems
PublicationIn 2011, the European Network and Information Security Agency (ENISA) conducted a study in the domain of Industrial Control Systems (ICS). Its objective was to obtain the current view on the ICS protectionprimarily in Europe but also in the international context. The portrait' included threats, risks, and challenges in the area of ICS protection as well as national, pan European, and international initiatives on ICS security. The...
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublicationApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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Employment and export specialisation along the development path: some robust evidence
PublicationThis paper contributes to the literature on the evolution of overall specialisation along the process of economic development by simultaneously estimating 'specialisation curves' emerging from fully comparable employment and export statistics in a sample of 32 economies (1980-2000). We apply semiparametric estimation methods, which allow us to combine the flexibility of the estimation with the inclusion of country-specific effects,...
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A new optimal algorithm for a time-dependent scheduling problem
PublicationIn this article a single machine time-dependent scheduling problem with total completion time criterion is considered. There are n given jobs j_1, ..., j_n and the processing time pi of the i-th job is given by p_i = 1 + b_is_i, where si is the starting time of the i-th job, i = 1, ..., n. If all jobs have different and non-zero deterioration rates and bi > bj => bi >= (b_min+1)/(b_min) b_j + 1/b_min, where b_min = min{b_i}, then...
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Intercultural Challenges in Virtual Teams
Publication: Virtual teams are usually geographically dispersed and consist of members from different countries and cultures. They influences internal communication processes and can cause personal conflicts, misunderstandings or lack of trust. Intercultural diversity is also significant for goal setting and team effectiveness. The aim of this article is to check if virtual team members appreciate the cultural diversity or rather suffer from lack...
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MEASUREMENT OF TEMPERATURE-DEPENDENT VISCOSITY AND THERMAL CONDUCTIVITY OF ALUMINA AND TITANIA THERMAL OIL NANOFLUIDS
PublicationIn this study results of simultaneous measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of two nanofluids, i.e. thermal oil/Al2O3 and thermal oil/TiO2 are presented. Thermal oil is selected as a base liquid because of possible application in ORC systems as an intermediate heating agent. Nanoparticles were tested at the concentration of 0.1%, 1% and 5% by weight within temperature range from...
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MEMS Gyro in the Context of Inertial Positionning
PublicationThe article undertake some vital aspect in geodesy, namely an inertial positioning problem using MEMS. Although MEMS inertial sensors offer affordable, appropriately scaled units, and though their inherent measurement noise can be relatively easily mitigated, there are still parameters due to they are not currently capable of meeting all requirements for the accurate and precise inertial positioning. The article presents crucial...
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Interaction of Acoustic and Thermal Modes in the Gas with Nonequilibrium Chemical Reactions: Possibilities of Acoustic Cooling
PublicationNonlinear generation of thermal mode during propagation of dominative sound in a chemically reacting gas is considered. The dynamic equation of excess temperature associated with the thermal mode is derived. It is instantaneous and includes quadratic nonlinear acoustic source reflecting the nonlinear character of interaction between acoustic and non-acoustic types of gas motion. Both periodic and aperiodic sound may be considered...
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Flow Analysis of a Kaplan Turbine
PublicationThis monograph is a guide to a method of experimental and numerical flow investigations for Kaplan - type turbines. The numerical calculations were compared with the test results of the model Kaplan turbine. The tests were carried out on the model test rig in the Gdańsk University of Technology. The turbine has been thoroughly experimentally investigated, resulting in the identification of optimum setting combination of the stator...
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Prosthetic Elements Made of the Ti-13Zr-13Nb Alloy by Selective Laser Melting
PublicationThe fabrication of the prosthetic foundations and bridges from the Ti-13Zr-13Nb alloy is described. The process was started from CAD/CAM design of 3D models of the foundations based on scanning of patient`s mouth. Next, 3D models were transformed into *.stl files for the manufacturing stage and then the manufacturing process by means of the selective laser melting with the SLM Realizer 100 equipment was made. The intrinsic structure...
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Analysis of Denoising Autoencoder Properties Through Misspelling Correction Task
PublicationThe paper analyzes some properties of denoising autoencoders using the problem of misspellings correction as an exemplary task. We evaluate the capacity of the network in its classical feed-forward form. We also propose a modification to the output layer of the net, which we called multi-softmax. Experiments show that the model trained with this output layer outperforms traditional network both in learning time and accuracy. We...
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Fashion and Tourism: Parallel Stories of Two "Dream Marvels".
PublicationFashion and tourism are two social, cultural, and economic phenomena that have both numerous connections and surprising similarities. These are not new: they have been built and developed since the beginnings of tourism as a modern social phenomenon, emerged in Europe in the context of the industrial revolution. They consolidated in the first decades of the 21st century, in a context where both phenomena have completed their “mass”...
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Employment of a Nonlinear Adaptive Control System for Improved Control of Dissolved Oxygen in Sequencing Batch Reactor
PublicationA proper control in a complex system, such as Wastewater Treatment Plant (WWTP) with each year is becoming increasingly important. High quality control can minimize an environmental impact as well as reduce operational costs of the WWTP. One of the core issues is providing adequate dissolved oxygen (DO) concetration for microorganisms used in a treatment process. An aeration process of the wastewater realised by an system consisting...
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Ionosphere variability II: Advances in theory and modeling
PublicationThis paper aims to provide an overview on recent advances in ionospheric modeling capabilities, with the emphasis in the efforts relevant to electron density variability. The discussion spans a wide range of model formulations (e.g., from purely empirical to physics-based ones and data-driven approaches) seeking for advances or gaps with regard to present challenges. This discussion is further supported by consideration of the...
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Promising Nanoparticle-Based Heat Transfer Fluids—Environmental and Techno-Economic Analysis Compared to Conventional Fluids
PublicationProviding optimal operating conditions is one of the major challenges for effective heating or cooling systems. Moreover, proper adjustment of the heat transfer fluid is also important from the viewpoint of the correct operation, maintenance, and cost efficiency of these systems. Therefore, in this paper, a detailed review of recent work on the subject of conventional and novel heat transfer fluid applications is presented. Particular...
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On description of periodic magnetosonic perturbations in a quasi-isentropic plasma with mechanical and thermal losses and electrical resistivity
PublicationMagnetosonic periodic perturbations in a uniform and infinite plasma model are considered. Damping due to compressional viscosity, electrical resistivity, and thermal conduction are taken into account, as well as some heating–cooling function, which may destroy the isentropicity of wave perturbations. The wave vector forms arbitrary angle h with the equilibrium straight magnetic field, and all perturbations are functions...
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Between Descriptive Geometry and CAD 3D
PublicationDescriptive geometry provides methods to analyse three-dimensional space through two-dimensional drawings and prepares to create technical documentation. Geometric form of an engineering project is presented by the means of projection methods based on a 3D model, which is present in designer’s imagination. The forthcoming era of Building Information Modelling (BIM) brings changes in the way the engineer works, as the vision is...
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Straightened characteristics of McKendrick-von Foerster equation
PublicationWe study the McKendrick-von Foerster equation with renewal (that is the age-structured model, with total population dependent coefficient and nonlinearity). By using a change of variables, the model is then transformed to a standard age-structured model in which the total population dependent coefficient of the transport term reduces to a constant 1. We use this transformation to get existence, uniqueness of solutions of the problem...
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THE INFLUENCE OF WSR PARAMETER ON PET BOTTLE THICKNESS PROFILE IN SBM FROM PREFORM PROCESS
PublicationFrom a mechanical point of view, the thickness profile of PET bottles manufactured by ISBM process is determined by mechanical and thermal response of blown preforms. From the microscopic point of view the biggest influence on the mechanical and thermal properties of PET bottles have orientation and crystallization processes. From a technological point of view, the thickness profile of PET bottles after manufacture by SBM process...
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Preface
PublicationThis special issue of Discussiones Mathematice Graph Theory (DMGT) is dedicated to selected papers presented at the 13th Workshop on Graph Theory: Colourings, Independence and Domination (CID) held on 18-23 September 2009 in Szklarska Poręba, Poland. It continues a series of international workshops: 1993-1997 in Lubiatów, 1998-2001 in Gronów, and 2003-2007 in Karpacz. The meeting was organized by the Faculty of Mathematics, Computer...
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Credibility of Threats to Jam Anonymous Traffic Remapping Attacks in Ad Hoc WLANs
PublicationIn ad hoc networks, selfish stations can pursue a better quality of service (QoS) by performing traffic remapping attacks (TRAs), i.e., by falsely assigning their traffic to a higher priority class, which can hurt honest stations’ QoS. To discourage the attackers, honest stations can announce their dissatisfaction with the perceived QoS. If such a threat fails, a costly data frame jamming defense can be launched. We analyze the...
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Quantum origins of objectivity
PublicationIn spite of all of its successes, quantum mechanics leaves us with a central problem: How does nature create a bridge from fragile quanta to the objective world of everyday experience? Here we find that a basic structure within quantum mechanics that leads to the perceived objectivity is a so-called spectrum broadcast structure. We uncover this based on minimal assumptions, without referring to any dynamical details or a concrete...
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Natural ventilation performance of family building in cold climate during windy days
PublicationAdequately designed natural ventilation is the cheapest and easiest way to effectively remove indoor pollutants and keep the fresh air inside a building. A prediction of performance and effectiveness of ventilation in order to determine the design of a ventilation system can provide real and long term cost savings. The paper presents results of performance (air change rate ACH) and effectiveness (CO2 concentration in the breathing...
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An application of acoustic sensors for the monitoring of road traffic
PublicationAssessment of road traffic parameters for the developed intelligent speed limit setting decision system constitutes the subject addressed in the paper. Current traffic conditions providing vital data source for the calculation of the locally fitted speed limits are assessed employing an economical embedded platform placed at the roadside. The use of the developed platform employing a low-powered processing unit with a set of microphones,...
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Microwave treatment in waste rubber recycling – recent advances and limitations
PublicationEnvironmentally-friendly microwave heating is increasingly used in polymer chemistry and technology. The selectivity and highly efficiency in the heat transfer present a huge advantage in systems based on recycling, improving their productivity and economic competitiveness. In case of the industrial recycling of waste rubbers, especially end-of-life tires, microwave-induced devulcanization and pyrolysis are nowadays considered...
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Innovative Railway Stations
PublicationIn relation to modern demographic trends, evolving technologies and environmentfriendly solutions increases the potential of rail considered as sustainable form of public transport. Contemporary tendencies of designing railway stations in Europe are focused on lowering energy consumption and reducing carbon emission. The main goal of the designers is to create a friendly and intuitive space for its users and at the same time a...
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Ionosphere variability I: Advances in observational, monitoring and detection capabilities
PublicationThe paper aims to review recent advances regarding the observational and monitoring capabilities of the ionization conditions in the Earth's upper atmosphere. The analysis spans both ground and space-based experiments, seeking for new installations and/or missions, new or upgraded instrumentation and/or observational network establishments as means for advancing current understanding and prediction ability of the ionosphere variability....
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Comparison of three methods of EPR retrospective dosimetry in watch glass
PublicationIn this article we present results of our follow-up studies of samples of watch glass obtained and examined within a framework of international intercomparison dosimetry project RENEB ILC 2021. We present three methods of dose reconstruction based on EPR measurements of these samples: calibration method (CM), added dose method (ADM) and added dose&heating method (ADHM). The study showed that the three methods of dose reconstruction...
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Relations between magnetosonic perturbations as an indicator of a magnetosonic exciter and equilibrium parameters of a plasma
PublicationThe thermodynamic relations between perturbation of pressure and pertur- bation of mass density and between components of velocity which specify a magnetosonic wave are theoretically studied. A planar flow with the wave vec- tor forming a constant angle with the equilibrium magnetic field is investigated. The theory considers deviation from the adiabaticity of a flow due to some kind of heating–cooling function and thermal conduction...
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Natural convection in symmetrically heated vertical channels
PublicationThe study describes natural convection through a vertical channel, open on four sides and bound by two isothermal walls. Both balancing and infrared experimental investigations were performed in air (Pr = 0.71) to estimate the impact of channel width s and wall-to-ambient temperature difference (tw - t∞) on natural convective heat transfer, the formation of air flow patterns and the rate of flow pattern formation. The study was...
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Epoxy/Ionic Liquid-Modified Mica Nanocomposites: Network Formation–Network Degradation Correlation
PublicationWe synthesized pristine mica (Mica) and N-octadecyl-N’-octadecyl imidazolium iodide (IM) modified mica (Mica-IM), characterized it, and applied it at 0.1–5.0 wt.% loading to prepare epoxy nanocomposites. Dynamic differential scanning calorimetry (DSC) was carried out for the analysis of the cure potential and kinetics of epoxy/Mica and epoxy/Mica-IM curing reaction with amine curing agents at low loading of 0.1 wt.% to avoid particle...
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The Effect of Cryogenic Treatment on Microstructure and Mechanical Response of AISI D3 Tool Steel Punches
PublicationRecently, deep cryogenic treatment is performed to improve the mechanical responses (wear, hardness, fatigue, and thermal conductivity) of various steel components. Researchers have tried to evaluate the eco-friendly and nontoxic process to optimize the parameters. Cold-shearing punches used to manufacture various holes that undergo severe impact loading and wear in the metal forming process. This study concerns the effect of soaking...