Effect Of Melting Point Research Articles

Effect of melting point and drying technique on encapsulation of hydrophobic active compounds by coprecipitation with starch nanoparticles

This study aims to optimize the coprecipitation method for the encapsulation of hydrophobic active compounds using starch nanoparticles (SNP). Saturated fatty acids with varying chain lengths (8, 18, and 22) were used as model compounds. Differential scanning calorimetry analysis revealed that various reaction conditions influenced the encapsulation efficiency of fatty acids, with 30% ethanol, an addition level of 10 mg/mL, heating for 30 min, and a cooling rate of 10 k/min, producing the highest melting enthalpy of the shifted thermal transition peak. Specifically, heating near the melting point of the guest compound resulted in substantial structural modifications between the guest compound and the SNP. D-δ-tocopherol, coenzyme Q10, and curcumin were then encapsulated under optimized conditions and dehydrated via spray- and freeze-drying. Transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffraction analyses revealed that each compound underwent spherical aggregation with SNP in an amorphous state via hydrogen bonding and hydrophobic interactions. Freeze-drying generally resulted in higher encapsulation efficiency than spray-drying. For D-δ-tocopherol and curcumin, freeze-dried composites exhibited higher storage stability under varying pH, UV irradiation, and thermal treatment conditions. However, for coenzyme Q10, spray-drying resulted in higher storage stability.

The effect of melting point and combination of phase change materials on the thermal control performance of small satellites in the thermal environment of low earth orbit: Numerical study

Thermal management of small satellites in the thermal environment of low earth orbit is a crucial task. Any satellite in low earth orbit is subjected to two distinct thermal conditions for the duration of its orbit: extreme hotness and extreme coldness. Phase change materials (PCM) are promising candidates for the thermal control of small satellites in low earth orbit thermal conditions. The present work provides a numerical analysis of a thermal storage panel (TSP) using PCM. The TSP is used to improve small satellites' thermal control performance in the thermal environment of a low earth orbit. An aluminium TSP is designed based on a typical space-approved small satellite battery. It is integrated with five internal fins as a thermal conductivity enhancer. The fins divide the heat sink into six cuboid cavities and are filled with PCM. Three-PCM materials with melting points of 15 °C, 21 °C, and 26 °C are used. The proposed low earth orbit is at an altitude of 500 km and a beta angle of 00; this resulted in an eclipse fraction of 0.37. The TSP is investigated under three levels of heating loads: 10W and 13 W. The TSP is investigated using both single and combinations of PCM. Four combination cases are investigated: (RT 15 & RT 21), (RT 21 & RT 26), (RT 15 & RT 26), and (RT 15 & RT 21 & RT 26). The results report a significant enhancement in the thermal control performance of the PCM-based TSP. At 10W and steady-state conditions, RT 15 records maximum extrema of 21.4 °C with a decreasing percentage of 34.6 % compared to the case without PCM. In addition, RT 15 records minimum extrema of 7.8 °C with an increase of 162.4 %. TSP with PCM combinations achieve a nearly constant PTD under varying heating loads and hence a constant temperature response amplitude. In addition, the PCM combinations achieve a nearly fixed specific heat with the change in heating load.

Optimization of thermal and electrical efficiencies of a photovoltaic module using combined PCMs with a thermo-conductive filler

The purpose of this study is an optimization of thermal and electrical efficiencies of a photovoltaic module using combined phase change materials (PCMs) with a thermo-conductive filler. Composites of beeswax and coconut oil (BWCO) and its mixture with paraffin (PBWCO) are introduced as novel PCMs and used to thermal regulation in a photovoltaic (PV) module. Terephthalic acid powder (TPA) is added to PBWCO to upgrade its thermal conductivity. The electrical and thermal efficiencies (ηe and ηth), as dependent variables, are investigated by the response surface methodology (RSM) to obtain the optimal condition of the PV/TPA-PBWCO system. The selected independent factors of the cooling system are beeswax weight fraction in BWCO (X1 = 0–100%wt), BWCO weight fraction in PBWCO (X2 = 0–50%wt), TPA weight fraction in PBWCO (X3 = 0–12%wt) and weight of PCM (X4 = 2.1–4.1 kg). Results show that for uncooled mode, ηe and ηth are 8.16% and 58.61%, respectively. The results illustrate the usage of BWCO put out higher electrical and thermal efficiencies than their pure ones. BWCOs with X1 > 45%wt and X1 < 45%wt suffer from high and low melting points, respectively. The results prove that PBWCO with X2 > 37.5%wt reduces the effect of the PCM, which is due to the increase of the melting point, although it has slightly increased the latent heat and thermal conductivity, the effect of melting point is more dominant. The addition of TPA to PBWCO remarkably enhances the cooling system performance. The predicted electrical and thermal efficiencies at the optimal point are 14.88% and 90.76%, respectively, at X3 = 8.48%wt and X4 = 3.253 kg.

Effect of melting point on thermodynamics of thin PCM reinforced residential frame walls in different climate zones

Energy consumption in building sector has increased dramatically over the past two decades. The incorporation of phase change materials (PCMs) into building envelopes is considered as an effective thermal energy storage strategy to improve building thermal performance and reduce space heating/cooling load. Despite significant efforts in PCMs technologies and their applications to buildings, how to effectively improve energy efficiency of latent heat generated from PCMs for building energy and how to select proper PCMs for buildings under different climate zones still post great challenges. Lack of systematic and comprehensive studies in these gaps hinder their broad applications in the building sector. To meet the need, this study aims to numerically explore the impacts of critical design parameters including PCM layer location, thickness, and the loading conditions associated with different climate zones and months on the selection of the PCM melting point. COMSOL Multiphysics® software is used to simulate multilayer walls containing PCM to unveil the thermal performance under various climate loading conditions. The results reveal that selecting proper PCM melting point according to those design parameters reduces the indoor peak temperature and temperature oscillation, and thus diminishes the energy consumption by the heating, ventilation, and air conditioning (HVAC) system to regulate the indoor temperature. The optimal PCM melting point is in direct proportion to the input loading conditions, suggesting that a higher PCM melting point is needed for a building envelope subjected to higher input temperature associated with climate zones. Results also show that PCM with a melting point within the occupant thermal comfort zone can increase indoor thermal comfort duration more effectively for the “moderate” climate loading conditions. The findings are expected to assist engineers with better utilization of the PCM-based building envelope in different climate regions.

Effect of Melting Point on the Physical Properties of Anhydrous Milk Fat

The effect of melting point on the physical properties of anhydrous milk fat were investigated. The results showed that high melting fractions (HMF) (S30,S35) were enriched in long-chain fatty acids, whereas low melting fractions (LMF)(S5,S10,S15) were enriched in short-chain and unsaturated fatty acids. From S5 to S35, enthalpy value was gradually increased on both crystallization and melting condition, so as SFC on different temperature. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of different fraction of AMF.

Provisional in-silico biopharmaceutics classification (BCS) to guide oral drug product development.

The main objective of this work was to investigate in-silico predictions of physicochemical properties, in order to guide oral drug development by provisional biopharmaceutics classification system (BCS). Four in-silico methods were used to estimate LogP: group contribution (CLogP) using two different software programs, atom contribution (ALogP), and element contribution (KLogP). The correlations (r2) of CLogP, ALogP and KLogP versus measured LogP data were 0.97, 0.82, and 0.71, respectively. The classification of drugs with reported intestinal permeability in humans was correct for 64.3%–72.4% of the 29 drugs on the dataset, and for 81.82%–90.91% of the 22 drugs that are passively absorbed using the different in-silico algorithms. Similar permeability classification was obtained with the various in-silico methods. The in-silico calculations, along with experimental melting points, were then incorporated into a thermodynamic equation for solubility estimations that largely matched the reference solubility values. It was revealed that the effect of melting point on the solubility is minor compared to the partition coefficient, and an average melting point (162.7°C) could replace the experimental values, with similar results. The in-silico methods classified 20.76% (±3.07%) as Class 1, 41.51% (±3.32%) as Class 2, 30.49% (±4.47%) as Class 3, and 6.27% (±4.39%) as Class 4. In conclusion, in-silico methods can be used for BCS classification of drugs in early development, from merely their molecular formula and without foreknowledge of their chemical structure, which will allow for the improved selection, engineering, and developability of candidates. These in-silico methods could enhance success rates, reduce costs, and accelerate oral drug products development.

Competition between elements during mechanical alloying in an octonary multi-principal-element alloy system

The competition between the constituent elements of the Cu 0.5NiAlCoCrFeTiMo alloy system during mechanical alloying was investigated and ranked with their alloying rates in getting alloyed in the mixture. By using XRD analysis, EDS mapping, extended X-ray absorption fine structure technique, and synchrotron radiation diffraction, the alloying sequence for the present alloy system is determined as Al → Cu → Co → Ni → Fe → Ti → Cr → Mo in the order of decreasing alloying rate. The alloying rate is found to correlate best with the melting point of the elements among metallurgical factors. The mechanism for this correlation is explained through the effect of melting point on solid-state diffusion and mechanical disintegration which are critical for the final alloying. This finding is valuable in predicting the alloying sequence of elements, and thus the phase evolution in multi-component alloys during mechanical alloying.

Physicochemical and Sensory Characteristics of Fish Gelatin

ABSTRACT:The physicochemical differences between pork and fish gelatin and the effect of melting point on the sensory characteristics of a gelatin‐water gel were investigated. Gelatin gel strength (measured as Bloom) and melting point of gelatin gels were measured, and quantitative descriptive analysis sensory tests were performed. The dependence of the gelatin gel strength and the melting point of fish gels on gel concentration, maturation time, maturation temperature, pH, and the influence of NaCl and sucrose were similar to those for pork gelatin. The flavored fish gelatin dessert gel product had less undesirable off‐flavor and off‐odor and a more desirable release of flavor and aroma than the same product made with an equal Bloom, but higher melting point, pork gelatin.

Radiation‐induced polymerization of glass‐forming systems. III. Effect of melting point and glass transition temperature on the formation of the glassy phase

AbstractThe general empirical rules about glass formation of organic compounds including monomers were studied. It was found that the difference of Tm (melting point) and Tg (glass transition temperature) was the most important factor in glass formation, that is, the glass‐forming property of organic systems, mono‐ or multicomponent, could be expressed as a function of Tm and Tm – Tg at the cooling temperature −196°C. The glassforming property was further divided into four classes according to the relation between Tm and Tm – Tg, and each class was related to several patterns in DTA curves. From these results it was clarified that the phases are completely or partially glassified depending on the different values of Tm – Tg in eutectic and noneutectic compositions. The overall phase diagrams covering the whole composition with the variation of Tm and Tg were determined, and they also supported the relationship between Tm – Tg and the glass‐forming property. The distinct glass‐forming property of binary systems with large molecular interaction was attributed to the great lowering of Tm and elevation of Tg in those systems. The effect of the number of components on glass formation was also studied; it was shown that if Tm, Tg, and ΔH (sum of heat of melting and of mixing) are given, the number of components necessary to glassification can be estimated.