Low Thermal Conductivity Values Research Articles

Sustainable materials with high insulation capacity obtained from wastes from hemp industry processed by wet-laid

This article reports on the revalorization of hemp waste from the textile industry, focusing on the development of new sustainable materials with high insulating properties. Wet-laid technology was used to manufacture nonwovens with different binding fibers, polylactic acid, and viscose fibers. The characterization of the acoustic insulating capacity was carried out using a Kundt tube, and the thermal insulating performance by measuring the heat transmission resistance ( R) and thermal conductivity ( λ). The results showed that the developed nonwovens have lower thermal conductivity values of about 0.027–0.034 W/(m K), were even lower than those of traditional thermal insulating materials, being the sample with 100 g/m2 of areal density and with a composition of 80% of hemp, 10% of polylactide and 10% of viscose the one with the lowest thermal conductivity (0.027 W/(mK). Their acoustic absorption capacity was around 0.76 at a frequency of 6 kHz, in samples containing high hemp waste (>80 wt%). However, the heterogeneous, discontinuous, and high void density structure that contributes to excellent insulating properties, lead to a decrease in their mechanical properties. This demonstrated that these materials are suitable for substituting traditional materials in insulating applications. Additionally, antifungal tests were carried out. However, hemp nonwovens proved to be inefficient against fungal proliferation.

Enhanced thermal performance of finned latent heat thermal energy storage system: fin parameters optimization

Integration of thermal energy storage (TES) systems in concentrated solar power (CSP) plants plays an important role, followingly, the mismatch between energy production and demand can be adjusted. Generally, latent heat thermal energy storage (LHTES) can ensure important amounts of energy compared to sensible heat thermal energy storage systems (SHTES), which has oriented researchers, engineers, and decision makers toward using this technology because of its high energy density. Otherwise, using phase change materials (PCMs) in LHTES systems can considerably reduce their performance as PCMs have relatively low thermal conductivity values, which makes it very necessary to take measures for enhancing the thermal conductivity or heat transfer inside of these LHTES units. This study simulated, modeled and optimized a proposed system for heat transfer enhancement, which is a shell-and-tube storage units with annular fins, by using the finite element method during the charging and discharging processes. In addition, NaNO3–NaNO2 was used as PCM while the Delco Term Solar E 15 was used as heat transfer fluid (HTF). The main objective of this work is to provide the optimal geometry parameters of the studied system in terms of length, number, step, and fin thickness by comparing many fin geometries. According to the results, an increase around 65.04% in the charging (melting) time and 58.36% in the discharging (solidification) period was achieved by the integration of optimal fins. The recommended fin parameters corresponding to the highest thermal performance were; length = 14 mm, thickness = 1 mm, step = 3.45 mm, and number = 66.

Petrophysical Property Modifications by Alteration in a Volcanic Sequence at IODP Site U1513, Naturaliste Plateau

AbstractPetrophysical properties of volcanic rocks are controlled by lithology and subsequent modification by alteration processes. Investigating the linkages, using a range of different techniques, are important to establish how petrophysical properties can inform about the alteration state of volcanic rocks. Here, we compile petrophysical data and correlate these with geochemical and mineralogical analyses acquired from a volcanic sequence on the Naturaliste Plateau, offshore southwest Australia (International Ocean Discovery Program Site U1513). The sequence consists of alternating basalt lava flows and volcaniclastic deposits, intruded by multiple dolerite dikes. Variable alteration intensities from fresh‐slight to strong are quantified using Chemical Index of Alteration. Intervals of slightly altered dikes exhibit low porosity and high values of bulk density, P‐wave velocity, and thermal conductivity. The increase of alteration intensity corresponds to decreases in bulk density to ∼2 g/cm3, P‐wave velocity to ∼2,000 m/s, thermal conductivity to ∼1.2 W/(m·K) and an increase in porosity up to 50%. Natural Gamma Ray and magnetic susceptibility vary downhole with rock composition and at lithologic boundaries. The distinct variations exhibit a good correlation with primary lithologic characteristics and secondary mineralogical and textural changes attributed to alteration processes. We provide synthesis models of petrophysical variation with alteration intensity. Although differences in primary lithology and alteration type introduce limitations and uncertainties, there is a reasonable applicability of our results to rapidly characterize the alteration intensity and volcanic stratigraphy in volcanic sequences and to calibrate wireline log‐based determinations. This will help others to develop strategies for exploration, drilling, and geophysical research of volcanic rocks.

High thermopower and birefringence in layered mercury-based halides

This work presents a theoretical investigation of mercury-based halides in both bulk and monolayer form. These compounds are direct bandgap semiconductors in bulk and monolayer form as it is evident from the analysis of structural and electronic properties. Birefringence values have been used to ascribe anisotropic optical properties, which may host future opto-electronic device applications. The values of mobilities for both the carriers in HgI2 are consistent with the experimental values. The low value of lattice thermal conductivity and favorable carrier mobilities provide a better scope for thermoelectric properties. The least bandgap of HgI2 further enables thermoelectric applications, and the thermopower is found to be high with a value of 580 μV/K for holes and nearly 320 μV/K for electrons. The thermoelectric efficiency for holes is quite appreciable with a figure of merit zT around 0.5 at 300 K for a carrier concentration of 1019 cm−3. In case of monolayers, the thermopower of HgI2 monolayer is found to be higher than its bulk counterpart. Our findings show that these compounds have robust transport and optical properties, which await future experimental verifications.

Enhanced figure of merit of TaIrGe Half-Heusler alloy for thermoelectric applications under the effect of isotropic strain

The structural, electronic and transport properties of the Half-Heusler TaIrGe compound have been reported at different values of tensile and compressive strain using density functional theory (DFT) in conjunction with Boltzmann transport theory. The mechanical and thermodynamical stability of TaIrGe at different values of isotropic strain is confirmed by the calculated value of elastic constants and the phonon dispersion curve, respectively. The electronic structure calculations reveals that the energy bandgap changes significantly on applying tensile and compressive strain. The calculated low value of lattice thermal conductivity (kl) and high value of power factor are key factors in enhancing the performance of resultant thermoelectric material. The calculated value of figure of merit (ZT) for pristine TaIrGe compound is 0.69 and it attains a maximum value (0.82) for 4% tensile strain at T ​= ​1200 ​K, which shows that it can be used as an efficient thermoelectric material under the effect of isotropic strain for high temperature applications.

Thermoelectric Properties of Hot-Pressed Ba3Cu14-δTe12.

The aim of this study was to investigate the thermoelectric properties of hot-pressed Ba3Cu14-δTe12 as well as its stability with regards to Cu ion movement. For the latter, two single crystals were picked from pellets after they were measured up to 573 and 673 K, which showed no significant changes in the occupancies of any of the Cu sites. All investigated Ba3Cu14-δTe12 materials displayed low thermal conductivity values (<1 W m-1 K-1) and appropriate electrical conductivity values (300-600 Ω-1 cm-1). However, the thermopower values were comparably low (<+65 μV K-1), resulting in uncompetitive zT values, with the highest being achieved for Ba3Cu13.175Te12, namely zT = 0.12 at 570 K. In an attempt to decrease the thermal conductivity, and thereby enhance the figure of merit, a brief alloying study with Ag was undertaken. The incorporation of Ag, however, did not produce any significant improvements.

Minute-Made, High-Efficiency Nanostructured Bi2Te3 via High-Throughput Green Solution Chemical Synthesis.

Scalable synthetic strategies for high-quality and reproducible thermoelectric (TE) materials is an essential step for advancing the TE technology. We present here very rapid and effective methods for the synthesis of nanostructured bismuth telluride materials with promising TE performance. The methodology is based on an effective volume heating using microwaves, leading to highly crystalline nanostructured powders, in a reaction duration of two minutes. As the solvents, we demonstrate that water with a high dielectric constant is as good a solvent as ethylene glycol (EG) for the synthetic process, providing a greener reaction media. Crystal structure, crystallinity, morphology, microstructure and surface chemistry of these materials were evaluated using XRD, SEM/TEM, XPS and zeta potential characterization techniques. Nanostructured particles with hexagonal platelet morphology were observed in both systems. Surfaces show various degrees of oxidation, and signatures of the precursors used. Thermoelectric transport properties were evaluated using electrical conductivity, Seebeck coefficient and thermal conductivity measurements to estimate the TE figure-of-merit, ZT. Low thermal conductivity values were obtained, mainly due to the increased density of boundaries via materials nanostructuring. The estimated ZT values of 0.8–0.9 was reached in the 300–375 K temperature range for the hydrothermally synthesized sample, while 0.9–1 was reached in the 425–525 K temperature range for the polyol (EG) sample. Considering the energy and time efficiency of the synthetic processes developed in this work, these are rather promising ZT values paving the way for a wider impact of these strategic materials with a minimum environmental impact.

Detection and Identification of Defects in 3D-Printed Dielectric Structures via Thermographic Inspection and Deep Neural Networks.

In this paper, we propose a new method based on active infrared thermography (IRT) applied to assess the state of 3D-printed structures. The technique utilized here—active IRT—assumes the use of an external energy source to heat the tested material and to create a temperature difference between undamaged and defective areas, and this temperature difference is possible to observe with a thermal imaging camera. In the case of materials with a low value of thermal conductivity, such as the acrylonitrile butadiene styrene (ABS) plastic printout tested in the presented work, the obtained temperature differences are hardly measurable. Hence, the proposed novel IRT method is complemented by a dedicated algorithm for signal analysis and a multi-label classifier based on a deep convolutional neural network (DCNN). For the initial testing of the presented methodology, a 3D printout made in the shape of a cuboid was prepared. One type of defect was tested—surface breaking holes of various depths and diameters that were produced artificially by inclusion in the printout. As a result of examining the sample via the IRT method, a sequence of thermograms was obtained, which enabled the examination of the temporal representation of temperature variation over the examined region of the material. First, the obtained signals were analysed using a new algorithm to enhance the contrast between the background and the defect areas in the 3D print. In the second step, the DCNN was utilised to identify the chosen defect parameters. The experimental results show the high effectiveness of the proposed hybrid signal analysis method to visualise the inner structure of the sample and to determine the defect and size, including the depth and diameter.

Enhanced in‐plane and through‐plane thermal conductivity and mechanical properties of polyamide 4.6 composites loaded with hybrid carbon fiber, synthetic graphite and graphene

AbstractPolyamide 4.6 has excellent properties, such as high temperature resistance, crystallinity, fatigue resistance, melting temperature, excellent creep resistance, toughness, and good wear properties, but low thermal conductivity values. For this reason, its use in thermal applications has been limited. In this study, its use in thermal applications can be increased by increasing its thermal conductivity with carbon‐based fillers and reinforcements added to the PA46 structure. The aim of this study is to examine the carbon fiber (CF), synthetic graphite (SG) and graphene nanoplatelet (G) loading on the mechanical, thermal, physical, and electrical properties of polyamide 4.6, which are produced using co‐ rotating twin‐screw extrusion. Tensile and flexural strength of polyamide 4.6 increased with the addition of CF at all weight fractions. The highest electrical conductivity value was measured as 4.01 S/cm in PA46‐20CF‐20SG‐3G composite material. The highest in‐plane thermal conductivity achieved in this study at 20 wt% CF, 20 wt% synthetic graphite, and 5 wt% graphene loading was 20.43 W/mK. However, the highest through‐plane thermal conductivity value was obtained to be 4.19 W/mK at 20 wt% CF. Graphene and synthetic graphite are more efficient to increase the in‐plane thermal conductivity, while CF is more efficient to increase the through‐plane thermal conductivity.

Estimation of the through-plane thermal conductivity of polymeric ion-exchange membranes using finite element technique

The aim of this study is to calculate the through-plane thermal conductivity of commercial polymeric ion-exchange membranes. Different membranes were considered to study the influence of membrane properties on the thermal conductivity values. In particular we focused on reinforcement, ion exchange capacity and membrane density and thickness. For this purpose, we use a simple experimental setup and a numerical simulation to estimate the thermal conductivity from the experimental temperature profiles. Once the system is calibrated, the model includes as the only unknown parameter the membrane thermal conductivity. To validate the method, the thermal conductivity of the well-known Nafion membranes has been determined, a very good agreement was achieved in context from reliable literature values. The study also provides the thermal conductivity of other polymeric ion-exchange membranes with great potential in diverse applications under non-isothermal conditions. The calculated thermal conductivity for the different ion-exchange membranes is in the range from 0.04 Wm−1K−1 to 0.42 Wm−1K−1. The results show that the reinforcement leads to lower values of thermal conductivity whereas a higher density or heterogenous structure leads to higher thermal conductivity values. The approach presented here, combining experimental and simulation techniques, may provide a basis for confirming the effect of the polymeric ion-exchange membrane properties on the thermal conductivity and may shed light on the best choice for the electrolyte of membrane-based applications performance under non-isothermal conditions.

Experimental Study of the Thermal Behavior of a Watercress Planted Roofed Cubic Cell to be Watered with Domestic Wastewater

One of the virtues of watercress is its ability to grow in wastewater. This work aims at experimentally studying the thermal behavior of a watercress planted roofed cubic cell. To do this, the temperatures of various components of the cell and the solar radiation received by this cell were measured in order to compare the watercress roof performance with that of the conventional concrete roof. Then, the influence of the opening applied on the door of the studied cell was analyzed. As results, the fluctuation amplitude of the indoor ambient temperature of the concrete roofed cell is wider than that of the green roofed cell. Moreover, the last opening applied to the facades of the cell was the optimum area that the ambient temperature indoor was more attenuated. The LAI’s crop was worth 1.2. In addition, the low value of the canopy apparent thermal conductivity revealed that this layer plays a role of thermal insulation. The rooftop greening allows energy savings of about 85% compared to the consumed energy with conventional roofing. An extension of this work could be the energy performance analysis of a system using renewable energy for pumping domestic wastewater produced in or around green roofed housing.

Mechanical and thermal properties of glass/epoxy composites filled with silica aerogels

ABSTRACT This paper investigates the effect of silica aerogels on mechanical (flexural and impact), non-destructive and thermal properties of glass/epoxy composites. Silica aerogels were mixed with epoxy at various volume fractions (1% and 3%) and infused with glass fabrics to produce composite laminates. Flexural tests indicated that the addition of aerogels increased the flexural strength of composites at the warp direction. Low impact energy (10–30 J) test results exhibited that impact force and energy absorption of composites were slightly increased . Higher energy (100 J) caused more severe damages and the effect of aerogels was more obvious. The thermogravimetric analysis revealed that addition of aerogels increased the thermostability. Generally, addition 1% of aerogel provides more improvement on mechanical properties and thermal stability compared to addition 3%. Although there is not a linear relationship between aerogel content and thermal conductivity, samples with 3% aerogel exhibited lower thermal conductivity values than other samples.

Thermoelectric properties of Mo-doped bulk In2O3 and prediction of its maximum ZT

In a search for new thermoelectric materials, indium oxide (In2O3) was selected as a candidate for high-temperature thermoelectric oxide materials due to its intrinsically low thermal conductivity (<2 W/mK) and ZT values around 0.05. However, low electrical conductivity is a factor limiting the thermoelectric performance of this oxide, and was addressed in this study by Mo doping. It was found that Mo is soluble in In2O3 but forms secondary phases at a fraction near x = 0.06 and higher. Mo was found to be unsuitable for heavy n-type doping necessary to improve the thermoelectric performance of the oxide to the desired level (ZT = 1). However, the experimental data enabled us to analyze the electrical conductivity behavior and the Seebeck coefficient of doped In2O3 with different carrier concentrations, predicting a theoretically achievable maximum power factor value of 1.77 × 10−3 W/mK2 at an optimum carrier concentration. This estimation predicts the highest ZT value of 0.75 at 1073 K, assuming the lattice thermal conductivity value remaining at an amorphous level.

Low-Density Insulation Blocks and Hardboards from Amaranth (Amaranthus cruentus) Stems, a New Perspective for Building Applications

Nowadays, amaranth appears as a promising source of squalene of vegetable origin. Amaranth oil is indeed one of the most concentrated vegetable oils in squalene, i.e., up to 6% (w/w). This triterpene is highly appreciated in cosmetology, especially for the formulation of moisturizing creams. It is almost exclusively extracted from the liver of sharks, causing their overfishing. Thus, providing a squalene of renewable origin is a major challenge for the cosmetic industry. The amaranth plant has thus experienced renewed interest in recent years. In addition to the seeds, a stem is also produced during cultivation. Representing up to 80% (w/w) of the plant aerial part, it is composed of a ligneous fraction, the bark, on its periphery, and a pith in its middle. In this study, a fractionation process was developed to separate bark and pith. These two fractions were then used to produce renewable materials for building applications. On the one hand, the bark was used to produce hardboards, with the deoiled seeds acting as natural binder. Such boards are a viable alternative to commercial wood-based panels. On the other hand, the pith was transformed into cohesive and machinable low-density insulation blocks revealing a low thermal conductivity value.

Improvement in physico-mechanical and structural properties of rigid polyurethane foam composites by the addition of sugar beet pulp as a reactive filler

Green polymeric composites, which are obtained from cheap, renewable, and environmentally friendly natural resources that can replace petrochemicals, have gained great attention from the researchers in recent years. To that end, we aimed at preparing a type of bio-based rigid polyurethane foam (RPUF) composites which incorporated sugar beet pulp (SBP) particles as a reactive filler. The obtained composite foams were evaluated through the effect of the increasing amount of SBP particles on the microstructure, thermal and mechanical properties. To eliminate the density effect of foams on the physico-mechanical properties, the foams were obtained such that their densities were kept at 37 $$\pm$$ 0.5 kg.m−3. Besides, the heat transfer mechanism of foams in terms of radiative transfer, conduction through polymer matrix and gas phase were analyzed by using a predictive model for the efficient thermal conductivity. Based on FTIR results, the functional groups on SBP have a tremendous tendency to react with isocyanates in the presence of a catalyst. The introduction of 3 wt% SBP according to the total mass provided high compressive strength (166 kPa), low thermal conductivity value (20.46 mW/m.K) and excellent dimensional stability in harsh conditions. SEM images show that the distribution of cells was uniform and any broken cells were not detected in all composite foams. The addition of SBP particles generally decreases the radiative contributions and enhances the contribution of conduction through the polymer matrix. It is clear that for all foams, the conduction through gas-phase gave the biggest contribution to the total thermal conductivity. Thermogravimetric analysis data displayed that the inclusion of SBP in RPUF slightly improved the thermal stability of RPUF composites. All results indicate that SBP waste, which is the most produced by-agriproduct in sugar refining industry, is an advantageous natural filler in many aspects for preparing RPUF. The obtained environmentally friendly RPUF composites have all of the properties needed to meet the demand for thermal insulation engineering materials.

Comprehensive study on the physical properties of tetragonal LaTGe3 (T = Rh, Ir, or Pd) compounds: An ab initio investigation

This study uses density functional theory to investigate the structural, mechanical, electronic, optical, and thermodynamic properties of tetragonal LaRhGe3, LaIrGe3, and LaPdGe3 compounds. The investigated lattice parameter showed similar results to the experimental data, justifying the accuracy of our calculations. The negative values of formation enthalpy confirmed the thermodynamic stability of LaTGe3 (T = Rh, Ir, or Pd). The mechanical stability of these compounds was also verified by their single independent elastic constants. Poisson’s and Pugh’s ratios revealed that all the compounds have a ductile nature. The metallic nature of these phases was found from their band structure calculations. The study of Mulliken bond populations and charge density maps ensured the existence of a mixed character of ionic, covalent, and metallic nature in LaRhGe3, LaIrGe3, and LaPdGe3 compounds. Detailed investigation was also performed on optical properties, and the dielectric function, absorption, and conductivity again ensured the metallic feature of all these phases. The calculated optical functions suggested their potential application in quantum-dot light emitting diodes, organic light emitting diodes, solar cells, waveguides, and solar heating reduction. Moreover, the very low values of minimum thermal conductivity and the Debye temperature are indicative of their suitability for thermal barrier coating materials.

An uncomplicated method for growing nano-quasicrystalline structures in the AlCuFeB quaternary alloy system: A short-time milling

Quasicrystals have been comprehensively studied since their discovery in 1984 by Daniel Shechtman to dissolve their complex structures concerning their physical properties [1–5]. The quasi-periodic well-ordered atomic structures made QCs as a novel type of solids differing from the crystalline or amorphous materials [5–7]. The QC alloys have non-crystallographic rotational symmetries, such as five-fold, eight-fold, and even ten-fold rotational axes that are prohibited in ordinary periodic crystals [5–7]. The QC alloys have been recently considered for several applications owing to a series of the unusual combination of exclusive physicomechanical properties for metallic-based alloys [5–7]. Accordingly, the properties of these alloys can be pointed out to their high strength, elevated hardness, desirable corrosion and wear resistance, minute adhesion, low values of thermal and electrical conductivity, and superior optical properties [5–7].•This paper focuses on the synthesis, structural and microstructural evolutions, thermal stability, microhardness, and electrical and optical properties of the Al59Cu25.5Fe12.5B3 nanoquasicrystalline alloy for solar selective absorber usages. Accordingly, there are various advanced techniques for synthesizing the nanostructured quasicrystals, such as laser ablation, sol-gel, electros pining, mechanical alloying, and hydrothermal methods.•The structural and microstructural evolutions of the mechanically alloyed AlCuFeB powders were investigated by X-ray diffractometry and field-emission scanning electron microscopy. The thermal stability of the AlCuFeB powders was recorded by differential thermal analysis.•The nanostructured Al59Cu25.5Fe12.5B3 stable quasicrystalline phase was synthesized by short-time milling procedure in 1 h. It was found that the presence of the quasicrystalline phase in the AlCuFeB alloy prominently improves the microhardness, electrical resistivity, and sunlight absorptance.

The Effects of Polystyrene Species and Fiber Direction on Thermal Conductivity of Plywood

Thermal conductivity of wood material is superior to other building materials because of its porous structure. Thermal conductivity is used to estimate the ability of insulation of material. Thermal conductivity of wood material has varied according to wood species, direction of wood fiber, specific gravity, moisture content, resin type, and addictive members used in manufacture of wood composite panels. The aim of study was to determine the effect of polystyrene species and fiber direction on thermal conductivity of plywood panels. In the study, two different wood types (black pine and spruce), two different fiber directions (parallel and perpendicular to the plywood fiber direction), two different types of insulator (expanded polystyrene-EPS and extruded polystyrene-XPS) and phenol formaldehyde glue were used as the adhesive type. Thermal conductivity of panels was determined according to ASTM C 518 &amp;amp; ISO 8301. As a result of the study, the lowest thermal conductivity values were obtained in the perpendicular fiber direction of the spruce plywood using XPS as insulation material. The use of XPS as an insulation material in plywood has given lower thermal conductivity values than EPS.

Thermal Conductivity of Lightweight Concrete Block with Various Cooling Agent

Energy was the important sources to human life. Due to increases energy demand in daily life, the energy consumption was increase day by day because of the heat load from solar radiation and heat produced by people. Toward sustainable development, this research was carried out to develop a lightweight concrete (LWC) block with various cooling agent such as glycerine, propylene glycol, coconut shell and gypsum powder. Six lightweight concrete (LWC) block with the size 250mm (L) × 250mm (W) × 100mm (T) were tested for thermal conductivity value. From the experimental result, it shows that lightweight concrete (LCW) block with various cooling agent obtained thermal conductivity value of 0.17W/mK - 0.36W/mK lower than thermal conductivity value for normal lightweight concrete (0.8W/mK) depending on concrete density. The lightweight concrete (LCW) block with cooling agent having low thermal conductivity value will reduce energy consumption in building.

Solidification enhancement in triplex thermal energy storage system via triplets fins configuration and hybrid nanoparticles

Latent thermal energy storage dependent on Phase Change Materials (PCMs) proposes a possible answer for modifying the availability of alternating energy from renewable sources such as wind and solar. They can possibly store large amounts of energy in moderately tiny dimensions as well as through almost isothermal procedures. Notwithstanding, low thermal conductivity values is a significant disadvantage of the present PCMs which critically restrict their energy storage usage. Likewise, this unacceptably decreases the solidification/melting rates, hence causing the system response time to be excessively lengthy. The present examination accomplished a better PCM solidification rate with a combination of hybrid nanoparticle (MoS2 - Fe3O4) and novel fin configuration in triplex-tube storage. A computational model that considers the natural conduction was represented and validated against previous experimental data. The influences of applying various nanoparticle volume fractions, radiation parameter, and shape factor on the assessment of the liquid-solid interfaces, phase change rate, and solidification process time over the whole solidification procedure was calculated and reported. The outputs demonstrate that PCM solidification is becoming better by utilizing the aforementioned methods. The obtained results disclose that the radiation parameter has a significant impact on the phase change rate, which shows a 74.58% contribution to the full solidification process time (FST). Additionally, the optimum parameters have designed to optimize the full solidification process time in the triplex-tube latent heat energy storage system (LHESS) system by using the Taguchi and Response Surface Methodology (RSM) methods. As a novelty, an accurate correlation for FST is developed with sensibly great precision.