Material Temperature Research Articles

Development of a novel concentrated solar-powered material extrusion system for producing printed circuit assemblies

A novel material extrusion system powered by Concentrated Solar Energy (CSE) for functional small-scale applications is proposed. The open literature has reported that any other system employs CSE to heat the extruding needle directly, which is the main component and function of any material extrusion device and the one that allows the building of the desired product or prototype. Polycaprolactone (PCL) is selected as the depositing material that gives shape to the substrates sheltering electric traces, resulting in a printed circuit assembly (PCA). A set of 15 experiments with different shapes allows the compilation of enough data to identify the exposure time and the direct radiation received as the main variables for obtaining the needed temperature for converting the depositing material to its rubbery state. Examples of functional circuits obtained by this device are included, showing his capabilities and potential. This information and the help of simulations on Computational Fluid Dynamics (CFD) software allow finding an expression of the material temperature at the depositing needle's exit as a function of the abovementioned variables. The obtained function describes the experimental equipment's behavior and has an average relative error of 12.6 % compared with the measured material's temperature at the depositing needle's exit. This proposal is expected to summarize the evidence of the CSE's potential for powering some manufacturing systems to obtain consumer goods and that a melt casting system mainly powered by CSE will be plausible shortly.

Thermo-mechanical finite element analysis of the solid-state metal deposition via lateral friction surfacing

Lateral friction surfacing (LFS) is a novel variation of the friction surfacing (FS) process for solid-state fabrication of ultra-thin and smooth metal coatings. In the LFS technique, pressing the lateral side of a rotating rod against the substrate's surface generates frictional heat and plastic deformation, leading to the deposition of consumable material from the lateral surface of the rod onto the substrate. This study presents numerical analysis for such a complex coupled thermo-mechanical process to investigate the distribution of various variables such as temperatures, local pressure, stress, and strain throughout the consumable rod and substrate. A finite element model of the process was developed through ABAQUS/Explicit method to investigate the thermo-mechanical response of rod and substrate materials by incorporating various features such as process parameters, mechanical behaviors of materials, temperature-dependent material properties, and failure criteria. The finite element model was validated by conducting experimental analysis using the same materials and values of process parameters. The finite element simulation results were consistent with previous experiments and affirmed that process temperature is lower than in conventional FS and localized in a small area, which can reduce thermal impacts on the consumable rod and substrate materials. Although the majority of the frictional heat was transferred to the Al6061-T6 rod due to its higher thermal conductivity, it was revealed that the maximum process temperature occurred on the mild steel substrate. The results of the study demonstrate that selecting an appropriate dwell-phase duration not only enhances the material's temperature to facilitate improved deposition but also ensures more consistent contact across all points along the rod's side, resulting in a uniform deposition.

Optimizing piezoelectric properties and temperature stability via Nb2O5 doping in PZT-based ceramics

High-performance piezoelectric ceramics with temperature stability can significantly enhance the functionality of transducers and sensors across a range of piezoelectric device applications. In this study, we investigated ceramics composed of 0.16Pb0.92Ba0.08(Mg0.5W0.5)O3-0.84 Pb(Zr0.43Ti0.57)O3 (PBMW-PZT) with varied Nb2O5 content. Notably, the ceramic doped with 1.0 wt% Nb2O5 exhibited superior piezoelectric properties (d33 ∼ 596 pC/N, kp ∼ 67%, and Tc ∼ 284 °C). Moreover, this ceramic demonstrated a stable performance with variations below 10% in the temperature range from 20 °C to 240 °C, surpassing many commercially available PZT-based ceramics. A combination of XRD, SEM, ferroelectric studies, and other in situ analytical methods indicated that this heightened piezoelectric response arises from a marked increase in reversible domain wall movement. The temperature-responsive Raman spectra suggest that the material's temperature stability primarily stems from its inherent structural integrity. Given these findings, the ceramic material in question emerges as an optimal choice for applications in piezoelectric devices, especially transducers and sensors.

Thermochromic glass laminates comprising W/VO2 nanoparticles obtained by wet bead milling: An in-depth study of the switching performance

The switching performance of W/VO2 nanoparticles in thermochromic glass laminates was investigated. W/VO2 powder was prepared, and displayed a phase transition temperature and switching enthalpy of 20.9 °C and 37.5 ± 0.2 J g−1, respectively. Using wet bead milling, the particle size was reduced from 24 ± 2 μm to 120 ± 10 nm. In the same process, the switching enthalpy decreased to 18.2 ± 0.6 J g−1 due to partial loss of crystallinity. The kinetics of the structural phase transition were studied using Friedman's differential isoconversional method. This demonstrated that the activation energy |Eα| was inversely proportional to the square of the difference between the material's temperature and the critical switching temperature T0, pointing out that nucleation kinetics were determining the rate. Furthermore, |Eα| decreased upon milling, and kinetic asymmetry was induced. The milled nanoparticles were compounded with PVB to produce thermochromic films, which were applied for laminating glass plates. The impact of nanoparticle size and concentration on the resulting optical properties of the laminate, viz. solar transmission and solar modulation, was studied in detail. The highest solar modulation obtained was 9.4%. The results obtained in this study are of direct importance for the application in smart windows, showing that (i) the W/VO2 particle size needs to be ≤ 100 nm to avoid excessive haze, (ii) both powder production and bead milling require further process optimization to minimize functional performance losses, and (iii) T0 should be set about 3 °C lower to ensure a sufficiently fast switch at the temperature of choice.

Preliminary investigation of temperature and pressure profile of pudam in the preparation of Siddha medicine Padigara parpam

BackgroundPudam is one of the manufacturing processes used extensively in preparing parpam and chenduram in the Siddha healthcare system. The scientific understanding of the process is not fully understood. ObjectiveIn this work, our objective was to investigate the temperature and pressure profile of the pudam process and also to understand the porous nature and low thermal conductivity of the sealed agal (Earthen vessel) used by replicating the traditional manufacturing process of Padigara parpam medicine in a pit. Materials and methodsThe temperature and pressure profiles were recorded. The size and mass of the cow dung cakes required to conduct the pudam process were discussed. The agal's porosity, thermal conductivity, and thermal diffusivity were experimentally determined. The pressure test of an empty agal was performed in an electric kiln and a pit to find the pressure development inside it and understand the sealed agal's role. ResultsThe maximum temperature of the pudam process was recorded as 807 °C, and the maximum heating and maximum cooling rate were calculated to be 30 °C/min and 8 °C/min, respectively. The holding time was found to be 66 min above 600 °C and 51 min above 700 °C. The maximum pressure built during the pudam process was 8.2 mbar. ConclusionThe test results indicate that the bottom location of the sealed agal is the optimum place to record the temperature of a pudam process. The sealed agal does not allow pressure to build inside, and the pudam process can be considered a heating process that occurs at atmospheric pressure. Increasing the quantity of cow dung cakes for the exact size of the sealed agal and pit increases the raw material's temperature and holding time and reduces the maximum heating rate.

Optimising Starch Transformation in Aquafeed Extrusion for Enhanced Water Stability and Performance

The physical quality of aquafeed pellets is paramount for the health and performance of aquatic species in aquaculture systems. Starch, a small, but necessary component of aquafeed, plays a crucial role in creating durable and water-stable pellets. This paper investigates the complex relationship between starch transformation during extrusion cooking and its influence on water stability. Through a series of experiments involving various extrusion parameters, including three melt moisture levels and three screw speeds, the study reveals that the key to producing water-stable aquafeed lies in optimizing starch gelatinization and minimizing dextrinization. High screw speeds, in conjunction with moderate to high melt moisture levels, facilitate starch gelatinization while avoiding dextrinization, resulting in pellets with superior water stability. Conversely, low melt moisture levels at any screw speed or any melt moisture at low screw speeds lead to poor water stability due to increased dextrinization or suboptimal gelatinization levels. The research also underscores the critical role of the glass transition of starch. Starch in its semi-crystalline state is found to be more susceptible to shear degradation during extrusion. Therefore, rapidly elevating the raw material's temperature above its glass transition temperature is crucial for achieving water-stable aquafeed.

A comparative study on the switching kinetics of W/VO2 powders and VO2 coatings and their implications for thermochromic glazing

Monoclinic VO2 (M) displays thermochromic properties based on its reversible metal-insulator transition. We studied the kinetics of the underlying structural phase transition (SPT) from monoclinic VO2 (M) to rutile VO2 (R) and vice versa both in powders and coatings, using isoconversional kinetic analysis based on datasets obtained through differential scanning calorimetry and UV–vis–NIR spectrophotometry. For VO2 powders, prepared via solution-phase reduction of V2O5 with oxalic acid and subsequent thermal anneal, we show that the activation energy |Ea| of the SPT is temperature dependent, and decreases with increasing difference between the material's temperature and the critical switching temperature T0. |Ea| for both VO2 (M) to VO2 (R) and VO2 (R) to VO2 (M) is similar, and ranges between 138 and 563 kJ mol−1, depending on the temperature of the material. This indicates that similar defects play a key role in both SPTs. Upon doping with tungsten, T0 was lowered from 66.93 °C (0 at. % W) to −28.38 °C (3.5 at. % W). |Ea|, however, remained in the same range. Nonetheless, at W concentrations above 2 at. % a significant asymmetry was observed with higher |Ea| for the switch from VO2 (R) to VO2 (M). The SPT of VO2 (M) in coatings proceeded 4 times slower. This may result from the immobilization of the VO2 domains on the substrate surface and within the coating network, making the SPT more difficult to progress. The findings of this study have important implications for the application of VO2 (M) in energy efficient thermochromic glazing.

Influence of plantation climate and storage time on thermal and viscoelastic properties of natural rubber

The Sociedad de Caucho Colombo Argentina (SOCCA) collected natural rubber (NR) from Yarima, Colombia, for seven months spanning two years. The unvulcanized NR was used to conduct a preliminary study, part of a long-term study, to uncover some underlying mechanisms in charge of imparting variation between NR batches, such as the collection site's rainfall conditions and storage period by using calorimetry, rheometry, and a dynamic mechanical analyzer. The ultrasound study found that an increase in monthly rainfall increased the material's elastic constant at 10 MHz, and the crystallization study uncovered that the amount of crystallization decreased with increased rain while remaining relatively constant if rainfall was within the recommended rainfall amount for the tree. Additionally, stress relaxation measurements revealed that an increase in rainfall suggested an increase in the material's temperature sensitivity. The temperature sensitivity relates to the material's processability in which an increase in temperature with high sensitivity will have a more drastic decrease in stress during a relaxation test compared to a material with low sensitivity.

Prediction of temperature and crystal growth evolution during 3D printing of polymeric materials via extrusion

Material Extrusion (ME), which is a type of Additive Manufacturing (AM), has become widely popular in the manufacturing world. However, the evolution of a material's temperature in this relatively new manufacturing method, which plays an important role in the polymer crystallinity, is not yet well researched. Next to voids, interlayer adhesion and surface roughness, the degree of crystallinity strongly determines the quality of printed products. Hence, a thorough and deep understanding of crystallinity in ME is essential for the improvement of the parts printed. In this paper, a primary generic model is proposed to predict the temperature evolution and crystal growth of printed polymer materials. The temperature evolution was developed based on the two-dimensional domain discretisation method and the crystal growth was simulated via the Hoffman-Lauritzen theory. In the simulation, key parameters have been taken into consideration, such as the printing speed, thermal convection coefficient, thermal contact conductance with the platform, nozzle diameter and latent heat in crystallisation. Then, a single-line printing scenario was tested to verify the accuracy of the model. A comparison of the model predictions with the experimental results showed only of up to 3.8 °C deviations which is a 2% of maximum percentage mismatch from the full scale reading.

Experimental Analysis on Double Layer Kapton Material using Peltier Thermoelectric Device

Kapton is one of the flexible materials used in the development of microwave components for the telecommunications system. The electrical properties of Kapton are dependent on the material's temperature. In this study, this material will be heated, and the electrical properties of dielectric permittivity and loss tangent will be analyzed. This material heating process is done by using Peltier thermoelectric which is installed with Aluminium alloy. The 0 V up to 7 V DC voltage was supplied to the Peltier during the heating process. Then, the electrical properties of Kapton were measured by using a dielectric probe and vector network analyzer (VNA) at frequencies of 1 GHz to 9 GHz. The results obtained show the Kapton temperature was increased from 27 o C to 41 o C. Meanwhile, the dielectric permittivity also varied from 1.72 to 1.64 at the frequency of 5 GHz when 4 V was used. The maximum loss tangent value of 0.5 was observed when the maximum DC voltage of 7 V was applied. The knowledge of this experimental work can be used to design reconfigurable microwave components for smart system applications

Experimental Analysis on Double Layer Kapton Material using Peltier Thermoelectric Device

Kapton is one of the flexible materials used in the development of microwave components for the telecommunications system. The electrical properties of Kapton are dependent on the material's temperature. In this study, this material will be heated, and the electrical properties of dielectric permittivity and loss tangent will be analyzed. This material heating process is done by using Peltier thermoelectric which is installed with Aluminium alloy. The 0 V up to 7 V DC voltage was supplied to the Peltier during the heating process. Then, the electrical properties of Kapton were measured by using a dielectric probe and vector network analyzer (VNA) at frequencies of 1 GHz to 9 GHz. The results obtained show the Kapton temperature was increased from 27 o C to 41 o C. Meanwhile, the dielectric permittivity also varied from 1.72 to 1.64 at the frequency of 5 GHz when 4 V was used. The maximum loss tangent value of 0.5 was observed when the maximum DC voltage of 7 V was applied. The knowledge of this experimental work can be used to design reconfigurable microwave components for smart system applications

Delay compensated control of the Stefan problem and robustness to delay mismatch

SummaryThis paper presents a control design for the one‐phase Stefan problem under actuator delay via a backstepping method. The Stefan problem represents a liquid‐solid phase change phenomenon which describes the time evolution of a material's temperature profile and the interface position. The actuator delay is modeled by a first‐order hyperbolic partial differential equation (PDE), resulting in a cascaded transport‐diffusion PDE system defined on a time‐varying spatial domain described by an ordinary differential equation (ODE). Two nonlinear backstepping transformations are utilized for the control design. The setpoint restriction is given to guarantee a physical constraint on the proposed controller for the melting process. This constraint ensures the exponential convergence of the moving interface to a setpoint and the exponential stability of the temperature equilibrium profile and the delayed controller in the norm. Furthermore, robustness analysis with respect to the delay mismatch between the plant and the controller is studied, which provides analogous results to the exact compensation by restricting the control gain.

Study on processing characteristics and mechanisms of thermally assisted laser materials processing

Nanosecond pulsed lasers have been widely applied to interact with and characterize many different materials, and industrial users are exploring more avenues for various application processes. For the purpose of achieving broader application, the current challenge is to achieve a high processing efficiency for laser materials processing. In this study, thermally assisted laser materials processing (TALMP), which introduces heat from an external source to increase the workpiece material's temperature and make it easier to carry out ablation or modification, was developed and investigated. Moreover, to investigate the materials processing characteristics and mechanisms of TALMP, practical applications using TALMP, including surface ablation on WC-Co, and surface polishing on additive manufactured Ti-6Al-4V, were carried out. The results showed that TALMP can be successfully applied to various materials by different laser materials processing applications. Due to the workpiece material's high temperature and heat content, the coupling between laser and target materials can be enhanced; thus, physical ablation and modification for laser surface ablation can be achieved effectively. However, with a high offset temperature, a little decrease of ablation accuracy and quality could occur, and a two-step approach is proposed to eliminate this unwanted effect. Moreover, this strategy is proven to be able to achieve the desired surface ablation with high efficiency and high-quality surfaces. For thermally assisted surface polishing, due to higher temperature field with long duration, a smoother and flatter polished surface can be obtained more easily. The experimental results proved the superiority and versatility of TALMP.

Development of an optical thermometry system for phosphor materials

This article focusses on the development of a basic system that can be used to investigate the emission of thermographic phosphors at various temperatures. In order to achieve this a standard photoluminescence system was utilised and modified. Modifications include a purpose-built heating unit, used to measure and control the phosphor material's temperature, a beam splitter together with a power meter to be used as a reference detector for the excitation source and a sample holder together with an XYZ stage that ensures position-stability and position-control for the samples throughout the measurements. A software program was developed to allow user-friendly control and automation of the modified system. The wavelength, excitation energy and temperature were calibrated as explained in this article. After this modifications and calibrations the system was used to study the emission of commercially available lanthanum oxysulphide doped with europium(III) phosphor material at different temperatures.

TEMPERATURE OF PLOUGHSHARE MATERIAL IN THE COURSE OF PLOUGHING

The change of temperature of subsurface layer material of ploughshare, occurring in the course of fine sandy loam (8% moisture and temperature 15.3°C) cultivation, done with bed making plough, was determined. Measuring system with 10 temperature sensors built in the ploughshare material was used in the research. Temperature value was registered with frequency of 1 Hz. The increase of temperature of subsurface layer of ploughshare blade material used in soil was fast – time of temperature stabilization was, depending on location the place of measuring from 17 to 43 s. In the course of ploughing the most heated was the initial area of the attack of landslide part of ploughshare blade and area adjacent to field edge – from 42.6 to 47.3°C. The temperature of material of trapezoid part of ploughshare blade was 26.6 to 29.7°C. In the conditions of the conducted measurements the rate of cooling of the subsurface layer of ploughshare blade material as the result of its cooling was 0.007 to 0.028°C·s-1 while plough was not working, however while making U-turns was from 3 to 7 times higher. In the places where the material of ploughshare blade was more heated the rate of cooling was of course higher. Faster cooling of ploughshare blade during U-turns was probably the result of intensified cooling induced by plough movement in the air.

Metal nitride coatings by physical vapor deposition (PVD) for a wear resistant aluminum extrusion die.

The purpose of this study is to investigate the friction and wear behaviors of CrN, TiN, CrAlN, and TiAIN coated onto SKD61 for application to Al 7000 series extrusion dies. On the wear test, the experimental parameters are the load and the counter material's temperature. The results showed that the friction coefficient increased with load but decreased with the counter material's temperature, and the friction coefficients of CrN and CrAIN were lower than the friction coefficients of TiAIN and TIN, especially at a higher temperature. The wear track with different coatings identified different wear behaviors; the wear behavior of CrAIN was found to be abrasive, but the wear behavior of TiN, CrN, and TiAIN was adhesive. Therefore, CrAIN showed the least wear loss with a lower friction coefficient and less adhesion with counter materials at the highest range of wear load and temperature. This resulted in the easy formation of aluminum oxide in the wear track and less Al adhesion; moreover during the hard second phase, AIN dispersed in the film during deposition.

Elastocaloric modeling of natural rubber

The elastocaloric effect is defined as the entropy change of a material when subjected to an external mechanical excitation. This article describes the elastocaloric effect of a natural rubber. Theoretical analysis leads to the global description of the material's temperature differential equation under mechanical stress. Based on energetic considerations, the temperature variations of the rubber sample can then be described as a function of the strain and of the supplied external thermal power. An experimental setup comprising a strain-controlled actuator coupled with a thermal measurement system has been developed in order to verify the accuracy of the proposed model. Finally a discussion on the possibility of using natural rubber for mechanical cooling is detailed.

Cleaning Up Water Blocking in Gas Reservoirs by Microwave Heating

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 101072, "Clean Up Water Blocking in Gas Reservoirs by Microwave Heating: Laboratory Studies," by Gao Li, Yingfeng Meng, SPE, and Hongming Tang, Southwest Petroleum Inst., China, prepared for the 2006 SPE International Oil & Gas Conference and Exhibition in China, Beijing, 5–7 December. Water blocking caused by fluid invasion during drilling, completion, and stimulation has been suspected of reducing or blocking gas-well deliverability. A technique that uses microwave heating to clean up water blocking in sandstone gas reservoirs is presented. Water-block cleanup by use of microwave heating is encouraging for field application, but further laboratory studies are required for the next phase of this project. Introduction Liquid will invade gas reservoirs when water-based fluids are used for drilling, completion, and stimulation. This water invasion will decrease the permeability, reducing flow capability or causing water blocking. Water blocking may lead to underestimating the gas-well productivity and reservoir value and to applying the wrong development strategy. Water blocking is a type of formation damage that restricts development of low-permeability gas reservoirs. Water blocking can be avoided or alleviated to some degree by use of underbalanced drilling, nonwetting-phase- and gas-based working fluids, and surface-tension-reduction techniques. After water blocking has happened, bypassing the damaged area may reduce the degree of damage (e.g., deep-penetration perforation, fracturing, and acid fracturing). Decreasing the water saturation of damaged areas (increasing drawdown, dry-gas injection, or extending shut-in time) or decreasing surface tension also may be effective. However, these methods cannot relieve water-block damage completely. Formation-heating technology (FHT) can improve the crude-oil fluidity, dehydrate clay, and enhance near-wellbore formation permeability and can be used to remedy water blocking by injecting hot gas to heat the formation near the wellbore. FHT has been tested and applied in oilfield production. However, FHT uses heat conduction and convection in the rock and gas to heat the formation. Because the heat capacity of gas is limited and heat conduction through rock is slow, the heating process is slow and inefficient. Microwave heating can heat materials rapidly and efficiently. Microwave heating is used to increase fluidity of heavy oil and to produce gas hydrate. This paper studied the influence of microwave heating on sandstone gas reservoirs and the feasibility of clearing water blockage. Basic Microwave Heating Microwaves are extremely high-frequency electromagnetic waves with a wavelength between 1 mm and 1 m and frequency from 300 GHz to 300 MHz, respectively. Used on dielectric materials, microwaves can cause electronic polarization or atomic polarization, interfacial polarization, and dipolarity turning to polarization. The polarization of dielectric materials can cause power dissipation, which raises the material's temperature. Conventional heating depends on heat conduction, convection, and radiation with slow heating from external to internal, while microwave heating can heat both the internal and the external at the same time with high heating speed and efficiency. Microwave energy can trans-form into heat energy instantaneously.

Effects of DC Current on the Mechanical Behavior of AlMg1SiCu

The effect of an electron wind on the mechanical properties of aluminum is investigated with the ultimate goal of establishing a technique by which the mechanical energy associated with the deformation of a material can be reduced without requiring a significant increase in the material's temperature. In the study presented herein, the effect that the electrical flow has on the mechanical properties of aluminum is examined through tensile testing. However, as electricity is passed through the material, some incidental resistive heating occurs. Therefore, in order to isolate the effect of the electrical flow from that resulting from resistive heat, the effect of transient temperatures on the stress–strain behavior of aluminum is also considered, with, and without, the presence of the electrical flow. In addition, variation in the electrical effect, with respect to the aluminum's temper and electrical pre-treating, is investigated. The experimental results indicate that the electrical current has the potential to substantially reduce deformation energies without causing significant increases in the workpiece temperature. The data also indicates that this effect exists regardless of the temper on the material. Finally, the study found that electrically pre-treating the aluminum produced results similar to that of an annealing process (i.e., the energies were significantly reduced).

Development in Laser Induced Extrinsic Absorption DamageMechanism of Dielectric Films

Absorption of host and the temperature-dependence of absorptioncoefficient have been considered in evaluating temperature distributionin films, when laser pulse irradiates on films. Absorption of dielectricmaterials experience three stages with the increase of temperature:multi-photon absorption; single photon absorption; metallic absorption.These different absorption mechanisms correspond to different band gapenergies of materials, which will decrease when the temperature ofmaterials increases. Evaluating results indicate that absorption of hostincreases rapidly when the laser pulse will be over. If absorption ofhost and the temperature-dependence of absorption are considered, themaximal temperatures in films will be increased by a factor of four.