Maximum Melting Temperature Research Articles

Melting temperature and elastic constants of disordered nonstoichiometric cubic TiCy, ZrCy and HfCy carbides

Based on the analysis of phase diagrams of carbide-forming systems M–C (M = Ti, Zr, Hf), an empirical relationship is proposed between the elastic stiffness constants cij of nonstoichiometric cubic carbides of titanium, zirconium and hafnium and their melting temperature. The dependences of the melting temperatures of nonstoichiometric cubic carbides TiCy, ZrCy and HfCy on their composition in homogeneity regions are calculated using the elastic stiffness constants c11(y) and c44(y) of these carbides. The calculated maximum melting temperatures are observed for carbides ~TiC0.80, ~ZrC0.82 and ~ HfC0.94–0.95 and are equal to 3345, 3708 and 4192 K, respectively. There is a qualitative correlation between the concentration dependences of the melting temperatures Tm(y) of TiCy, ZrCy and HfCy carbides and the anisotropy of the elastic properties of these carbides.

New milk protein anisotropic structures formed by high moisture extrusion

In this work, the formation of anisotropic, layered structures from milk protein concentrates was investigated using high moisture extrusion. These structures were obtained in combination with three concentrations of starch (0 %, 14 %, and 33 %, d.b), and at three different moisture levels: 58 %, 63 %, and 68 %. Two different temperature profiles were investigated, reaching a maximum barrel temperature of 80 and 115 °C (and maximum melt temperature of 56 and 64 °C, respectively), with a constant screw speed and feed rate. In situ monitoring of torque, as well as the evaluation of water partitioning via proton relaxometry highlighted the interplay between moisture content and barrel temperature in starch transitions and water intake. For example, the presence of starch displayed water populations of distinct mobility, featured by higher relaxation times, and the apparition (or intensification) of new peaks representing free water in the system. The extruded samples showed a multi-phase system with swollen starch granules embedded in a protein network when 14 % starch was used, at moisture <63 %, as depicted by confocal microscopy. Tensile strength and cutting force tests showed a broad range of textures, from more brittle at high starch concentration, to softer and mushier when extruded at high moisture. Increasing starch and moisture content disrupted the protein network structure. This work demonstrated that milk protein concentrates show great potential to create novel anisotropic structures by extrusion, with tunable texture properties depending on starch, moisture and temperature conditions.

Mechanical, Thermal Properties of Virgin, Recycled and Mixed High-Density Polyethylene Matrices and Wood Plastic Composites with Plywood Sanding Dust

Virgin high-density polyethylene (vHDPE), recycled (rHDPE), and mixed vHDPE/rHDPE matrices and wood plastic composites based on these mixtures + 50 wt.% of plywood sanding dust (PSD) and 3 wt.% coupling agent maleated polyethylene (MAPE) physical-mechanical properties (tensile, flexural strength and modulus, impact strength, and microhardness) were investigated. It was observed that all defined properties depend on the content of rHDPE in the pure polymer matrix and corresponding WPCs. Tensile strength and modulus decreased a bit, but flexural modulus actually had no changes. At the same time, a decrease in impact strength and a significant increase (up to 2 times) in microhardness are observed. From all the investigated matrices, the most perspective seems to be the matrix with a vHDPE/rHDPE ratio of 75/25, whose mechanical properties are acceptable for the preparation of the WPCs based on plywood sanding dust. The compatibilization possibilities tests of different mixed matrices done by the DSC method in the air showed that the mixed vHDPE/rHDPE compositions compatibility is sufficiently good at different proportions. For all mixed matrices, only one relatively symmetric band with one peak of melting was observed. Differential scanning calorimetry (DSC) tests in an inert environment showed that during the first heating cycle, HDPE components are only partially compatible (two peaks of melting temperatures are possible to fix). On the contrary, after the cooling and crystallization processes, during the second heating of the same sample, these two bands completely merge, and like in the air, only one maximum melting temperature peak was observed. The values of thermal oxidation temperature and melting temperature are the highest for virgin vHDPE but the lowest for rHDPE. The values of all corresponding parameters of mixed matrices reduce proportionally with an increase in rHDPE content in the mixtures.

Determining the maximum melting temperature of polymer crystals from a change in morphology of dewetting rims

Dewetting experiments on molten spherulites, previously grown at Tc = 120 °C in thin films of isotactic polypropylene (iPP), revealed two kinds of instabilities of the dewetting rims, namely a fingering instability and a fracture instability for dewetting temperatures Ts above and below ca. 165 °C, respectively. For Ts ≥ 165 °C, the dynamics of growing dewetting holes on slippery substrates was governed by viscous dissipation, causing undulations leading to a fingering instability of the rims. However, for 160 °C < Ts < 165 °C, the dewetting rims exhibited a fracture instability, which was related to the release of elastic energy stored in the rim. From the dewetting dynamics of the molten polymers, we derived the non-equilibrium viscosity ηnon-equ(Ts) and equilibrated viscosity ηequ(Ts) as a function of Ts. The values of ηnon-equ(Ts) were significantly larger than ηequ(Ts), with differences decreasing for increasing Ts. Interestingly, extrapolation of ηnon-equ(Ts) to the cross-over point ηnon-equ = ηequ yielded Ts,cross ≈ 166 °C. We relate Ts,cross with the maximum melting temperature of crystalline domains which existed within iPP spherulites. Below Ts,cross, not all crystallites were molten and the melt contained crystalline seeds. Above Ts,cross, the melt was homogeneous and free of any seeds. Our approach opens up a new possibility for determining the maximum melting temperature of polymer crystals.

Improving antibody thermostability based on statistical analysis of sequence and structural consensus data.

BackgroundThe use of Monoclonal Antibodies (MAbs) as therapeutics has been increasing over the past 30 years due to their high specificity and strong affinity toward the target. One of the major challenges toward their use as drugs is their low thermostability, which impacts both efficacy as well as manufacturing and delivery.MethodsTo aid the design of thermally more stable mutants, consensus sequence-based method has been widely used. These methods typically have a success rate of about 50% with maximum melting temperature increment ranging from 10 to 32°C. To improve the prediction performance, we have developed a new and fast MAbs specific method by adding a 3D structural layer to the consensus sequence method. This is done by analyzing the close-by residue pairs which are conserved in >800 MAbs’ 3D structures.ResultsCombining consensus sequence and structural residue pair covariance methods, we developed an in-house application for predicting human MAb thermostability to guide protein engineers to design stable molecules. Major advantage of this structural level assessment is in significantly reducing the false positives by almost half from the consensus sequence method alone. This application has shown success in designing MAb engineering panels in multiple biologics programs.ConclusionsOur data science-based method shows impacts in Mab engineering.

Coaxiality Optimization Analysis of Plastic Injection Molded Barrel of Bilateral Telecentric Lens

Plastic optical components are light in weight, easy to manufacture, and amenable to mass production. However, plastic injection molded parts are liable to shrinkage and warpage as a result of the pressure and temperature variations induced during the molding process. Consequently, controlling the process parameters in such a way as to minimize the geometric deformation of the molded part and improve the performance of the optical component as a result remains an important concern. The present study considered the problem of optimizing the injection molding parameters for the plastic lens barrel of a bilateral telecentric lens (BTL) containing four lens assemblies. The study commenced by using CODE V optical software to design the lens assemblies and determine their optimal positions within the barrel. Taguchi experiments based on Moldex3D simulations were then performed to determine the processing conditions (i.e., maximum injection pressure, maximum packing pressure, melt temperature, mold temperature, and cooling time) which minimize the coaxiality of the plastic barrel. Finally, CODE V and grayscale analyses were performed to confirm the optical performance of the optimized BTL. The Taguchi results show that the coaxiality of the plastic lens barrel is determined mainly by the maximum packing pressure and melt temperature. In addition, the CODE V and grayscale analysis results confirm that the optimized BTL yields a better modulus transfer function, spot diagram performance, and image quality than a BTL produced using the general injection molding parameters.

МОДИФИКАЦИЯ СИНТЕТИЧЕСКОГО СЫРЬЕВОГО МАТЕРИАЛА НА ОСНОВЕ ГИДРОКСИДА НАТРИЯ ДЛЯ ПОЛУЧЕНИЯ СТЕКЛА

The research continues the direction of intensification of glass-making processes by completely replacing soda ash in the glass batch with sodium hydroxide to obtain a well-classified intermediate two-component raw material. A method for obtaining a modified synthetic raw material (SRMm) for producing sodium-calcium-silicate glass based on quartz-containing raw material and sodium hydroxide is considered. SRMm consists of two parts, the chemical composition of one of which corresponds to the low-melting eutectic on the Na2O-SiO2 diagram, in contrast to the prototype SRM, the chemical composition of which corresponds to the chemical composition of silicate glass. The products of the synthesis of parts of quartz sand and sodium hydroxide are mixed with the rest of the components of the glass batch of alkali-silicate glasses, followed by possible agglomeration by known methods. The results of a comparative X-ray phase analysis of experimental charges, as well as heat-treated pelletized samples, show more pronounced glass formation processes in a charge based on SRMm than using the prototype. The use of experimental charges can intensify the physicochemical reactions at the stage of melting in a glass-making furnace, reduce the maximum melting temperature of glass, reduce the carryover of dust-like components of the charge and the technogenic load on the environment.

Verifying laboratory measurement of the performance of hot asphalt mastics containing plastic waste

As a response to the “end of waste” strategy, this study focuses on an innovative laboratory-methodological approach to carrying out measurements for multi-scale characterization of road pavements construction materials; specifically, the engineering performance of sustainable hot asphalt mastics made up using plastic waste as filler was measured to gain a deeper understanding of the physico-machanical performance of traditional and modern mastics, which seriouly affect the design and durability of the final whole road asphalt pavement. Asphalt mastics are bitumen-based materials that give cohesion to the whole asphalt mixture. They consist of filler (with a passing by mass percentage ranging from 70 to 100 for a sieve size of 0.063 mm) and bitumen.Nine asphalt solutions prepared using three percentages of filler content (10, 15, and 20%) by the total weight of neat bitumen whose weight was kept constant were investigated.Firstly, for plastic waste particles, the maximum melting temperature was examined using Differential Scanning Calorimetry, and the phase transitions were subjected to thermogravimetric analysis. The morphology of all the asphalt solutions was then observed using Scanning Electron Microscope, while the advanced rheological properties were measured by means of a Dynamic Shear Rheometer.Cluster Analysis and Principal Component Analysis were performed to aggregate solutions with similar performance within the same group, and, secondly, to provide a small number of uncorrelated explanatory laboratory variables. Three clusters and three Principle Components were found to be perfectly interconnected to describe asphalt mastics performance.

Ice induction using Snomax® in the dimethyl-sulfoxide-containing aqueous solution for DSC experiments

Controlling the supercooling state during ice crystallization process is important for differential scanning calorimetry (DSC) analysis. In cryopreservation solutions, the control of the nucleation temperature (Tn) is necessary as it allows the simulation of slow-freezing procedures. Herein, the effect of Snomax® on Tn value in aqueous solutions containing dimethyl-sulfoxide (Me2SO) (H2O + 10 %(v/v)Me2SO) was studied. The effect of Me2SO, a cryoprotectant, on nucleation control was investigated by evaluating λhet, which describes the influence of a molecule on the nucleation behaviour of an ice-nucleating agent (INA). Note that λhet is specific to the molecule added in solution and to the maximum melting temperature of the solution. The knowledge of λhet helps evaluate the ranges of the supercooling magnitude at which the INA in solution can trigger nucleation. This study shows how Snomax can be used in DSC experiments using the H2O + 10 %(v/v)Me2SO solution when ice nucleation must be controlled.

Structure-Properties Correlation of Lead Selenide-Lead Selenite Composite

The main areas of work are related to the synthesis of a two-phase composite (1-x)PbSe·xPbSeO3 in the form of a powder, faceted single crystal, film and compacted material with the possibility of changing the fraction (x) of the PbSeO3 phase from 0 to 1 by oxidation of PbSe in a dry atmosphere in the temperature range 20-550 °С and the study of its physicochemical properties. All initial samples are obtained by the original method from Pb1-ySey powder, in which the composition corresponds to the maximum melting temperature of the compound and is defined as ysmax=0.500025±0.000025 at. Se. The powder is crushed, after which homogenizing annealing is performed at a constant temperature (~750 °C) in a dynamic vacuum in order to achieve the minimum general pressure condition. The noted precursor-related technological procedures are necessary to achieve congruent evaporation conditions in all types of samples and help minimize the concentration of inherent defects and inclusions in phase two. Depending on application, it is possible to form crystalline powders with a given ratio of volumetric phases PbSe and PbSeO3 in a separate grain. For all cases, the "shell" for semiconductor particles PbSe is the dielectric phase PbSeO3. The principal possibility of forming the smallest (up to nanometer) grains of lead selenide in the dielectric matrix of lead selenite is shown. According to the proposed method, the synthesis of lead selenite by oxidation of lead selenide is possible.

Structure and physical properties of gelatin from bovine bone collagen influenced by acid pretreatment and pepsin

Effects of different acids and pepsin on the properties of gelatins extracted from bovine bone collagen were investigated. Pretreatment of bovine bone by different acids (hydrochloric acid, acetic acid, and citric acid) with and without pepsin was performed at 70 °C for 7 h to extract gelatin. Under the different acid treatments, the yield of gelatin was significantly different (hydrochloric acid, 4.76%; acetic acid, 4.26%; citric acid, 6.00%). Compared to no pepsin incubation group, bovine bone collagen treated with pepsin presented a higher yield (P < 0.05). Scanning electron microscopy analysis showed that citric acid disrupted more of the collagen structure compared with acetic acid and hydrochloric acid. Raman spectra revealed that all extracted gelatins had the similar secondary structure. Rheological analysis indicated that gelatin extracted with citric acid exhibited the highest maximum elastic modulus, gelling and melting temperature. Overall, the gelatin yield was affected by the type of pretreatment acid and more optimal gelatin extraction and gel properties were obtained when citric acid was used for extraction. Collagen pretreated with acid and pepsin was more efficiently extracted for gelatin compared to treatment without pepsin.

Evaluation of the physicochemical, thermal and behavioural properties of consciousness energy healing treated iron (II) sulphate

Iron (II) sulphate is used as a source of iron to treat iron deficiency anemia. In this study evaluated the impact of the Trivedi Effect®- Consciousness Energy Healing Treatment on the physicochemical, thermal, and behavioural properties of iron sulphate using modern analytical techniques. Iron sulphate sample was divided into control and treated parts. Only treated sample received the Trivedi Effect®-Consciousness Energy Healing Treatment remotely by a famous Biofield Energy Healer, Mr. Mahendra Kumar Trivedi. The powder XRD relative peak intensities and crystallite size of the treated iron sulphate were significantly altered ranging from -87.25% to 338.67% and from -58.33% to 99.84%, respectively compared to the control sample. The average crystallite size of the treated iron sulphate was significantly decreased by 5.68% compared with the control sample. The particle size values of the treated iron sulphate was decreased by 1.54% (d10), 1.12% (d50), 2.51% (d90), and 1.90% {D(4,3)} and the surface area was increased by 4.69% compared with the control sample. The melting temperature of the four peaks (1st-4th) of the treated sample was decreased by 0.28%, 12.45%, 5.44%, and 0.51%, respectively compared to the control sample. The latent heat of fusion of 1st, 2nd, and 4th peaks in the treated sample was decreased by 47.29%, 75.39%, and 0.29%, respectively, whereas 3rd peak was increased by 8.02% compared with the control sample. The total weight loss in the treated iron sulphate was increased by 0.78% compared with the control sample. The maximum thermal melting temperature of the treated sample was slightly increased by 2.03% in the 1st peak; but decreased by 1.53%, 12.64%, and 1.27% in the 2nd, 3rd, and 4th peaks, respectively compared to the control sample. Overall results suggested that the Trivedi Effect®-Consciousness Energy Healing Treatment might lead to the production of a new polymorphic form of iron sulphate, which would be more soluble and bioavailable, compared to the untreated sample. The Trivedi Effect® treated iron sulphate would be useful to design more efficacious nutraceutical/pharmaceuticals, which might offer better therapeutic response against iron deficiency anemia.

Assessment of hemolytic activity of bee venom against some physicochemical factors

Abstract Bee venom (BV) is a biotoxin with biologically active peptides which have cell lysis and hemolytic activity properties. These properties can be affected under different storage conditions or during the production process. In present study, we investigated effects of a number of physicochemical factors, including temperature, pH, UV radiation, ultrasound waves and storage time on hemolytic activity of BV. Maximum absorption and melting temperature of BV solution were obtained as 280 nm and ~70 °C, respectively. Cell hemolysis 50 (CH50) -concentration of BV that can lyse 50% of red blood cells- was determined as 0.94 μg/ml at ambient temperature. CH50 was shown not to be importantly varied at temperature up to 60 °C, pH value 2 to 13 and under UV/ ultrasound radiation. Storage at −20, 6 and 25 °C for 6 months made about 2.5, 35 and 1000 times increase in CH50. From the results, it may be concluded that BV is a relatively resistant hemolytic agent and can be used in a variety of laboratory research and product manufacturing methods.

Melting behaviour of uranium-americium mixed oxides under different atmospheres

In the context of a comprehensive campaign for the characterisation of transmutation fuels for next generation nuclear reactors, the melting behaviour of mixed uranium-americium dioxides has been experimentally studied for the first time by laser heating, for Am concentrations up to 70 mol. % under different types of atmospheres. Extensive post-melting material characterisations were then performed by X-ray absorption spectroscopy and electron microscopy. The melting temperatures observed for the various compositions follow a markedly different trend depending on the experimental atmosphere. Uranium-rich samples melt at temperatures significantly lower (around 2700 K) when they are laser-heated in a strongly oxidizing atmosphere compressed air at (0.300 ± 0.005) MPa, compared to the melting points (beyond 3000 K) registered for the same compositions in an inert environment (pressurised Ar). This behaviour has been interpreted on the basis of the strong oxidation of such samples in air, leading to lower-melting temperatures. Thus, the melting temperature trend observed in air is characterized, in the purely pseudo-binary dioxide plane, by an apparent maximum melting temperature around 2850 K for 0.3 < x(AmO2) < 0.5. The melting points measured under inert atmosphere uniformly decrease with increasing americium content, displaying an approximately ideal solution behaviour if a melting point around 2386 K is assumed for pure AmO2. In reality, it will be shown that the (U, Am)-oxide system can only be rigorously described in the ternary U-Am-O phase diagram, rather than the UO2-AmO2 pseudo-binary, due to the aforementioned over-oxidation effect in air. Indeed, general departures from the oxygen stoichiometry (Oxygen/Metal ratios ≠ 2.0) have been highlighted by the X-ray Absorption Spectroscopy (XAS). Finally, to help interpret the experimental results, thermodynamic computations based on the CALPHAD method will be presented.

Holistic QbD approach for hot-melt extrusion process design space evaluation: Linking materials science, experimentation and process modeling

The aim of this work was to investigate the relationship between formulation material properties, process parameters and process performance for the manufacturing of amorphous solid dispersions via hot-melt extrusion (HME) using experimentation coupled with process modeling. Specifically, we evaluated the impact of the matrix copovidone melt rheology with and without the addition of a plasticizing surfactant, polysorbate 80, while also varying the process parameters, barrel temperature and screw speed, and keeping fill volume constant. To correlate the process performance to a critical quality attribute, we used telmisartan as an indicator substance by processing at temperatures below its solubility temperature in the polymeric matrix. We observed a broader design space of HME processes for the plasticized formulation with respect to screw speed than for the copovidone-only matrix formulation. This observation was determined by the range of observed melt temperatures in the extruder, both measured and simulated. The reason was not primarily linked to a reduced shear-thinning behavior, characterized by the power law index, n, but instead more to an overall reduced melt viscosity during extrusion and zero-shear rate viscosity, η0, accordingly. We also found that the amount of residual crystallinity of telmisartan correlated with the simulated maximum melt temperature in the extruder barrel. This finding confirmed the applicability of the temperature-dependent API-matrix solubility phase diagram for HME to process development. Given the complex inter-dependent relationships between material properties, process and performance, process modeling combined with reduced laboratory experimentation was established as a holistic approach for the evaluation of Quality-by-Design-based HME process design spaces.

Thermophysical properties of the most refractory carbide Ta0.8Hf0.2C under high temperatures (2000–5000 K)

We studied the carbide Ta0.81Hf0.19C0.94 in the form of a thin deposited layer (1 μm) under rapid heating (5 μs) by electric current pulse. We obtain the properties of this carbide: melting heat; specific heat, and enthalpy in the solid phase from 2000 K up to Tmelt = 4300 K, and for the first time in the liquid state up to 5000 K. We measured the temperature by high-speed radiation pyrometer calibrated against the tungsten temperature lamp. Here, we confirm the earlier obtained experimental data on the melting temperature of this compound obtained by black body model and thus, we confirm that this compound has the maximum melting temperature as against the other refractory carbides (TaC and HfC). Under fast heating, the steep increase of the specific heat of the carbide Ta0.81Hf0.19C0.94 for 400 K before melting was observed.

Polypropylene/carbon nanotube magnetic composites obtained using carbon nanotubes from sawdust

Magnetic polypropylene (PP) nanocomposites with different loadings (from 0.5 to 20 wt %) of carbon nanotubes with iron (CNT‐Fe) were fabricated using the melt‐mixing method. The carbon nanotubes were synthesized by pyrolysis of sawdust from the furniture industry. The morphological characterization shows homogenous dispersion of the filler in the polymer matrix. The addition of only 0.5 wt % CNT‐Fe already results in ferromagnetic behavior in the diamagnetic polymer matrix. The thermal properties were investigated using thermogravimetric analysis and differential scanning calorimetry. The results show an increase in the maximum degradation, crystallization, and melting temperatures of the nanocomposites compared with neat PP. The nanocomposites showed improvement in terms of mechanical and oxygen permeability properties. A very significant result of the work is the high remnant magnetization and coercivity values of the nanocomposites at room temperature whereas most of the works on similar systems show magnetic properties only at very low temperatures.

Fundamentals of organometallic electrophosphors synthesis under controlled temperature and ligand partial pressure

A new technique for analysis of "Ligand partial pressure - Temperature" diagram has been developed for the organometallic phosphor tris(8-hydroxyquinoline) M (M = Al, Ga, In). The detection of mono- and bivariant equilibriums within the p8-Hq-T diagram has been done using simultaneous measurements of photoluminescence and reflection spectra of a condense phase under controlled p8-Hq and T. Using preparations with the purity better than 99.999 wt% the corresponding p8-Hq-T diagrams have been plotted in the temperature range from 350 K to the maximum melting temperatures of the compounds. The homogeneity ranges of different polymorphs have been determined. For the different polymorphs it have been demonstrated that changing the synthesis conditions within the homogeneity range of the phases resulted to the significant changes of the nonstoichiometry, chemical activities and electroluminescent properties of the OLED structures, prepared on the base of β-Mq3.

Polypropylene biocomposites reinforced with bamboo particles and ultrafine bamboo‐char: The effect of blending ratio

Bamboo particles (BPs) and ultrafine bamboo‐char (UFBC) were introduced into polypropylene (PP) biocomposites by melt‐blending and injection molding, to improve the mechanical and thermal properties of PP matrix. The maximum tensile strength of 30.59 MPa was obtained when the ratio was 70/25/5, which was improved by 30% than that of pure PP. The maximum tensile modulus of 460.13 MPa was achieved when the ratio was 70/20/10, which was enhanced by 109%, 35% and 24% than that of neat PP, PP/BP (70/30), and PP/UFBC (70/30), respectively. The mechanical and thermal properties of the biocomposites were improved through adding UFBC. Improvement evidences on interfacial interaction and elemental distribution were observed by scanning electron microscope and energy dispersive spectrum analysis. The maximum melting temperature of 166.6°C was achieved that was increased 5.9°C than neat PP. Crystallization temperature was significantly improved with the increasing of UFBC and BP loadings. POLYM. COMPOS., 39:E640–E646, 2018. © 2018 Society of Plastics Engineers

Thermal Stability and Effect of Heat Treatment on Manganese Doped Silica Borotellurite Glass

Glasses with chemical formula of {[(TeO2)0.7(B2O3)0.3]0.8[SiO2]0.2}1-x{MnO2}x where x = 0.00 ≤ x ≤ 0.05 molar fraction were fabricated using melt quenching technique. The temperature used in the heat treatment process of the glass sample is 600?C. Calorimetric measurement had been carried out to study the thermal properties of the fabricated glass. The crystallization kinetics of the glass system we reexamined under non-isothermal conditions via differential scanning calorimetric (DSC). The glass transition (Tg), onset glass transition (To), maximum crystallization temperature (Tc) and melting temperature (Tm) were determined. Results from DSC proved that the studied glasses have good thermal stability (Ts) in which indicates its high resistance to devitrification. Strong indicator for the glass forming ability of a glass material, Hurby parameter (Kgl) was also calculated in this research.