Differential Scanning Calorimetry Curves Research Articles

Physicochemical properties and flavor substances analyses of refined beef tallow with dry fractionation treatment

Dry fractionation represents a significant technique for separation of diverse fractions from beef tallow. The objective of this study was to undertake a systematic investigation of alterations in physicochemical properties, crystallization behavior, thermal properties, and flavor compounds that occur during the beef tallow dry fractionation process. The solid component yielded at 40, 30, and 15 °C were 44.88%, 33.72%, and 13.04% respectively, with an 8.36% liquid content at 15 °C, which was consistent with the characteristics of saturated fatty acids content. The β – β’ transformation in the dry fractionation process was clearly revealed by X-ray diffraction. Differential scanning calorimetry curves exhibited alterations in exothermic and endothermic peak, as well as enthalpy. Electronic nose identified short-chain compounds, aldehydes, ketones, and nitrogen-containing substances as flavor compounds. Volatile compounds were quantified using HS-SPME-GC–MS. Overall, dry fractionation produces beef tallow fractionated compounds with diverse physicochemical properties and aromatic-active substances, thereby expanding its potential utilization.

The thawing process in gentamicin and polyethylene glycol hydrogel: The impact of selected parameters on the calculation of activation energy using the methods of Belichmaer and Duswalt

AbstractThe subject of the research conducted by differential scanning calorimetry (DSC) was hydrated mixtures of polyethylene glycol and gentamicin (GEN) in a 1:1 (w/w) ratio. In this way, a system with a particularly high ability to form hydrogen bonds was created. It was postulated that studying the effective activation energy (EA) of the thawing process of diverse hydrated polymer mixtures will indirectly allow for an attempt to assess the distribution of water molecules in the examined material in future studies. This article presents a detailed analysis of the impact of selected parameters on the calculation of EA using the Belichmaer and Duswalt methods. The research focused on assessing how the interpolation method affects the accuracy of results obtained from these techniques. The interpolation method was analyzed in terms of its ability to accurately replicate experimental data. By evaluating the impact of the number of points from the DSC curve used in linear interpolation, a standard deviation from the average value of EA was obtained, respectively: 2.4% for the Belichmaer method and 1.9% for the Duswalt method. The article also shows that by using both methods simultaneously, it is possible to detect the moment when additional endothermic and exothermic reaction activity becomes present in the reaction curve. This allowed for the avoidance of the depletion error. Computer modeling and simulations were used to compare the effectiveness of both techniques in various scenarios. The results showed that the choice of interpolation method and taking into account the depletion error significantly affect the accuracy of calculating EA. The computed activation energy via Duswalt method was EA = 363.32 kJ mol−1 with a standard deviation of 7.07 kJ mol−1 and using the Belichmaer method the EA was 364.81 kJ mol−1, with a standard deviation of 9.10 kJ mol−1.

Unraveling the interaction mechanism between orphan drug Nitisinone and bovine serum albumin through spectroscopic and in silico approaches

The interaction between Nitisinone (NTBC) and bovine serum albumin (BSA) as the transport protein in a circulating system was investigated for the first time utilizing various analytical (UV–Vis spectrophotometry, fluorescence spectroscopy, dynamic light scattering, and differential scanning calorimetry) and computational (molecular docking and molecular dynamics simulations) methods. The BSA fluorescence intensity was quenched upon interaction with NTBC, and the quenching mechanism was observed as static. The interaction between NTBC and BSA was examined at 288 K, 298 K, and 308 K where the binding constants were found to be 1.44 × 105 ± 0.22 M−1, 5.18 × 104 ± 0.20 M−1, and 3.02 × 104 ± 0.22 M−1 respectively, suggesting an intermediate binding affinity between NTBC and BSA. Changes in the microenvironment surrounding tryptophan and tyrosine residues of BSA were elucidated using 3-D fluorescence spectroscopy. Thermodynamic studies revealed the calculated values of ΔH = − 54.34 ± 5 kJ/mol and ΔS = − 0.0908 ± 0.24 kJ/mol K−1, indicating the involvement of van der Waals forces and hydrogen bonds in the interaction between NTBC and BSA. Moreover, the interaction’s spontaneous nature was evidenced by negative ΔG values across all temperatures. Using dynamic light scattering, it was observed that higher NTBC concentrations led to a gradual rise in hydrodynamic diameter and notable aggregation of the NTBC-BSA complex. Moreover, changing signal values and shifted peaks of BSA, NTBC, and complex in differential scanning calorimetry curves, meant there were molecular interactions between the NTBC and BSA. In silico approaches also elucidated how NTBC binds to active sites on BSA, further supporting other findings. Moreover, molecular docking studies offer a more profound insight into the changing dynamics of hydrophobic, hydrogen, and halogen bonding involved in stabilizing the NTBC-BSA complex.

PHB+aPHA Blends: From Polymer Bacterial Synthesis through Blend Preparation to Final Processing by Extrusion for Sustainable Materials Design.

The inherent brittleness of polyhydroxybutyrate (PHB), a well-studied polyhydroxyalkanoate (PHA), limits its applicability in flexible and impact-resistant applications. This study explores the potential of blending PHB with a different PHA to overcome brittleness. The synthesis of PHA polymers, including PHB and an amorphous medium-chain-length PHA (aPHA) consisting of various monomers, was achieved in previous works through canola oil fermentation. Detailed characterization of aPHA revealed its amorphous nature, as well as good thermal stability and shear thinning behavior. The blending process was carried out at different mass ratios of aPHA and PHB, and the resulting blends were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The blends exhibited complex DSC curves, indicating the presence of multiple crystalline forms of PHB. SEM images revealed the morphology of the blends, with PHB particles dispersed within the aPHA matrix. TGA showed similar thermal degradation patterns for the blends, with the residue content decreasing as the PHB content increased. The crystallinity of the blends was influenced by the PHB content, with higher PHB ratios resulting in an increased degree of crystallinity. XRD confirmed the presence of both α and β crystals of PHB in the blends. Overall, the results demonstrate the potential of PHB+aPHA blends to enhance the mechanical properties of biopolymer materials, without com-promising the thermal stability, paving the way for sustainable material design and novel application areas.

Shaping the structure and properties of HyTemp using polyethylene glycol diglycidyl ether cross‐linkers

AbstractNovel elastomers are made by reaction of hydroxyl‐terminated polyacrylic ester (HyTemp) with polyethylene glycol (PEG, number of ethylene glycol units 1, 3, 6, 9) based cross‐linkers. The influence of the cross‐linker length, the HyTemp/cross‐linker (w/w) ratio and the cross‐linking accelerator trifluoromethanesulfonate scandium salt (ScTFMS) on the structure and the properties of the materials are studied. The cross‐linker length has not influence on the glass transition (Tg) of the products because of the presence of the flexible PEG units that cancels out the cross‐linking effect associated to a shift to higher Tg. A two‐domain structure is seen by the presence of a dual Tg in samples cured with ScTFMS. Mathematical analysis of the modulated differential scanning calorimetry curves offers for the first time the possibility to identify/confirm structural differences in complex three‐dimensional polymeric structures. Scanning electron microscopy and swelling experiments in ethyl acetate respectively reveal an increase in the pore size (1.13 to 5.48 nm) and in the absorption ability of the elastomers cured with different types and quantities of PEG cross‐linker. The new elastomeric materials are exhibiting a rubbery state over a wide temperature range and absorptivity for the potential recovery of pollutants in soil and/or water.

Structural, morphological, and dielectric properties of poly(vinylidene fluoride)/(Bi0.5Ba0.25Sr0.25) (La0.5Ti0.5) O3 composites

AbstractFerroelectric flexible polymer composite films of poly(vinylidene fluoride) (PVDF) with different weight percentages (10.0%, 20.0%, 30.0%, 40.0%, and 50.0%) of (Bi0.5Ba0.25Sr0.25) (La0.5Ti0.5) O3 were synthesized by solvent casting method. Analysis using the x‐ray diffractometer and Fourier transform infrared spectroscopy tools revealed the presence of the different phases (α, β) of PVDF. Scanning electron microscope morphology illustrates the homogenous dispersion of ceramics particles in the matrix. The differential scanning calorimetry curve (under 25–400°C) gives the value of melting temperature (Tm=169.98°C) and percentage crystallinity is about 29.45% for 50 wt.% composite. The findings demonstrated that the composite has good thermal stability up to 169.98°C. Dielectric analysis shows ferroelectric and dielectric behavior and also distinguishes α and β phases of PVDF. It was found that the composite film containing 50 wt.% (Bi0.5Ba0.25Sr0.25) (La0.5Ti0.5) O3 had a dielectric constant (εr) of 38 (at 100 Hz) and dielectric loss of 0.059, which are the maximum among the samples. The relative permittivity rises with an increase in filler content due to electrostatics and interfacial polarization between PVDF (CH2CF2 dipole) and ceramic. The real and imaginary part of impedance spectroscopy with frequency (Cole–Cole plots) for composite (10.0–50.0 wt.%) at 25°C are also investigated. The current study provides a fresh perspective on the fact that PVDF‐(Bi0.5Ba0.25Sr0.25) (La0.5Ti0.5) O3 composite system has improved thermal stability and dielectric characteristics.

Мultivariate analysis for rapid screening and prediction of solid-state compatibility in pharmaceutical preformulation studies-paving the road for machine learning

Multivariate analysis models were developed to evaluate the results obtained from a compatibility study designed for ibuprofen with a large group of different types of excipients, as a possible approach for rapid screening of the incompatibility between the active pharmaceutical ingredient (API) and excipients. The solid-state characterization of the binary mixtures was performed by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) using SIMCA® software were applied for evaluation of the experimentally obtained results. The optimal PCA model for the FTIR spectra explains 96.2 % of the variations in the dataset with good statistical indicators (R2X = 0.960, Q2 = 0.900), which was also the case for the PCA model for the DSC curves (R2X = 0.981, Q2 = 0.866). The applied PLS-DA models have shown similar behaviour to the PCA. Moreover, the main spectral variations in the FTIR spectra and the thermal events in the DSC data were attributed the highest variable importance for the projection (VIP) scores in the corresponding VIP plots, confirming the model capability for predicting ibuprofen interactions. Furthermore, the prediction power of the optimal models for FTIR and DSC experimental data was evaluated by the root mean square error of prediction (RMSEP) of 0.10 and 0.16, respectively. The obtained results demonstrated the potential of multivariate statistical analysis as a machine learning-based technique for screening and prediction of ibuprofen-excipients solid-state compatibility in the preformulation phase of the pharmaceutical development of dosage forms.

Synergistic co-pyrolysis of corn stover and refuse-derived fuel with microplastics: Kinetic and thermodynamic study

Biomass and refuse-derived fuel are prevalent constituents of municipal solid waste worldwide, exerting persistent pressures on environmental ecosystems. Consequently, there arises a critical necessity for their effective recycling and management. This study investigates the co-pyrolysis of corn stover (CS) and Refuse-Derived Fuel (RDF) in a 1:1 mass ratio through kinetic and thermodynamic analyses. Using a thermogravimetric analyzer and differential scanning calorimetry (DSC), the co-pyrolysis process is examined within a temperature range of 25–900 °C, under varying heating rates of 5, 10, and 20 °C/min in a nitrogen atmosphere. Kinetic analysis is conducted employing model-free methods, including Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Starink, and Tang, with subsequent estimation of thermodynamic parameters such as enthalpy change (ΔH), entropy change (ΔS), and Gibbs free energy (ΔG). Additionally, mass and energy balances specific to the blended feedstock are calculated to evaluate future operational efficiency. The investigation reveals the higher heating values (HHV) of CS and RDF as 17.879 and 20.035 kJ/kg, respectively. Notably, the DTG and DSC curves indicate a positive interaction between CS and RDF's plastic component at temperatures exceeding 400 °C. Kinetic analysis yields average activation energies for CS, RDF, and the CS-RDF blend (1:1) as 202.26, 235.87, and 212.60 kJ/mol, respectively, suggesting a reduction in activation energy for the blend. In summary, these findings offer valuable insights into the co-pyrolysis of CS and RDF, thereby contributing to the optimization of co-pyrolysis as an effective waste-to-energy conversion process.

A model of heterogeneous undercooled liquid and glass accounting for temperature-dependent nonexponentiality and enthalpy fluctuation.

Dynamic heterogeneity is a fundamental characteristic of glasses and undercooled liquids. The heterogeneous nature causes some of the key features of systems' dynamics such as the temperature dependence of nonexponentiality and spatial enthalpy fluctuations. Commonly used phenomenological models such as Tool-Narayanaswamy-Moynihan (TNM) and Kovacs-Aklonis-Hutchinson-Ramos fail to fully capture this phenomenon. Here we propose a model that can predict the temperature-dependent nonexponential behavior observed in glass-forming liquids and glasses by fitting standard differential scanning calorimetry curves. This model extends the TNM framework of structural relaxation by introducing a distribution of equilibrium fictive temperature (Tfe) that accounts for heterogeneity in the undercooled liquid. This distribution is then frozen at the glass transition to account for the heterogeneous nature of the glass dynamics. The nonexponentiality parameter βKWW is obtained as a function of temperature by fitting the Kohlrauch-Williams-Watts (KWW) equation to the calculated relaxation function for various organic and inorganic undercooled liquids and glasses. The calculated temperature dependent βKWW shows good agreement with the experimental ones. We successfully model the relaxation dynamics far from equilibrium for two silicate systems that the TNM model fails to describe, confirming that temperature dependent nonexponentiality is necessary to fully describe these dynamics. The model also simulates the fluctuation of fictive temperature δTf during isothermal annealing with good qualitative agreement with the evolution of enthalpy fluctuation reported in the literature. We find that the evolution of enthalpy fluctuation during isothermal annealing heavily depends on the cooling rate, a dependence that was not previously emphasized.

Extraction and characterization of microcrystalline cellulose from Vachellia nilotica plant leaves: A biomass waste to wealth approach.

Biobased waste utilization is an intriguing area of research and an ecologically conscious approach. Plant-based materials can be used to render cellulose, which is an eco-friendly material that can be used in numerous aspects. In the current investigation, cellulose was extracted from the leaves of the Vachellia nilotica plant via acid hydrolysis. The application of this research is specifically directed toward the utilization of undesirable plant sources. To validate the extracted cellulose, FT-IR spectroscopy was applied. The cellulose was measured to have a density of 1.234 g/cm3. The crystallinity index (58.93%) and crystallinity size (11.56 nm) of cellulose are evaluated using X-ray diffraction spectroscopy analysis. The highest degradation temperature (320.8°C) was observed using thermogravimetry and differential scanning calorimetry curve analysis. The analysis of particle size was conducted utilizing images captured by scanning electron microscopy. Particle size of less than 30 μm was found and they exhibit non-uniform orientation. Additionally, atomic force microscopy analysis shows an improved average surface roughness (Ra), which increases the possibility of using extracted cellulose as reinforcement in biofilms.

Differential scanning calorimetry of age-hardenable aluminium alloys: effects of sample preparation, experimental conditions, and baseline correction

Precipitation processes in age hardenable aluminium alloys are often investigated by differential scanning calorimetry (DSC). The endothermic and exothermic peaks of the DSC signal correspond to the dissolution and formation of phases, respectively. However, parasitic effects can lead to an unintended curvature of the DSC signal. Although a baseline correction can be used, some imperfections typically remain. Additionally, sample preparation and experimental conditions can influence the precipitation sequence itself and, therefore, the DSC curve. In this study, we investigate the influence of sample preparation by milling and punching on DSC curves for three different aluminium alloys: EN AW-2024, EN AW-6082, and EN AW-7075. Additionally, the influence of quenching and natural ageing was investigated for EN AW-6082. We found that deformation introduced by punching the DSC samples with a piercing die after heat treatment leads to a change in the precipitation kinetics in 2xxx, 6xxx, and 7xxx series alloys. The influence was strongest for punching the samples after solution heat treatment and less significant for punching after artificial ageing. The influence of sample preparation can be avoided by punching the samples before solution heat treatment. If this is not practicable, milling of the samples is a good alternative. The choice of quenching medium and short storage at room temperature before measurement (5 min) had only small effects on the DSC curves. Moreover, the start temperature of the measurement was found to be crucial. For observing phases forming below 100 °C and for low-bias baseline correction, the measurement should start at low-temperatures (i.e. ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} − 50 °C).

Preparation and Investigation of a Nanosized Piroxicam Containing Orodispersible Lyophilizate.

Non-steroidal anti-inflammatory piroxicam (PRX) is a poorly water-soluble drug that provides relief in different arthritides. Reducing the particle size of PRX increases its bioavailability. For pediatric, geriatric, and dysphagic patients, oral dispersible systems ease administration. Moreover, fast disintegration followed by drug release and absorption through the oral mucosa can induce rapid systemic effects. We aimed to produce an orodispersible lyophilizate (OL) consisting of nanosized PRX. PRX was solved in ethyl acetate and then sonicated into a poloxamer-188 solution to perform spray-ultrasound-assisted solvent diffusion-based nanoprecipitation. The solid form was formulated via freeze drying in blister sockets. Mannitol and sodium alginate were applied as excipients. Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were used to determine the particle size. The morphology was characterized by scanning electron microscopy (SEM). To establish the crystallinity, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used. A disintegration and in vitro dissolution test were performed. DLS and NTA presented a nanosized PRX diameter. The SEM pictures showed a porous structure. PRX became amorphous according to the XRPD and DSC curves. The disintegration time was less than 1 min and the dissolution profile improved. The final product was an innovative anti-inflammatory drug delivery system.

Effect of Heating Rate on Melting Point of HMX, RDX, TNT and PETN

Melting point of HMX, RDX, TNT and PETN are measured for judging crystal purity. The heating rate when doing this has a significant effect on the melting point reading. This work gives an insight on how heating rate affects the melting point reading for these high explosives using Differential Scanning Calorimetry (DSC). With increase in heating rates (from 1 to 20°C min-1) the different behaviours of the DSC curves for HMX, RDX, TNT and PETN are analysed. It is also observed from this study that heating rate causes a shift in the temperatures for onset and the peak for HMX, RDX, TNT and PETN. This study reflects that in some cases the decomposition of the explosives is influencing the melting graphs. Hence a conclusion has been drawn on the adequate heating rate that should be chosen for determining the melting point of these high explosives.

Evaluation of the Bioenergy Potential of Blends (Green Coconut Shells and Fish Scales) as a Feedstock in Thermochemical Processes for Clean Energy Production

Brazil is among the world’s largest producers of green coconut, which contributes to inappropriate disposal and socioenvironmental impacts. Concomitantly, some of its coastal cities produce a great diversity of fish and large amounts of solid waste. This paper reports on the use of samples of fish scales (100FS) and green coconut shells (100GCS) and their mixtures in 75%FS:25%GCS (B25), 50%FS:50%GCS (B50), and 25%FS:75%GCS (B75) proportions and quantification of their Higher Heating Values (HHV) and Lower Heating Values (LHV), and Ultimate (UA) and Proximate Analyses (PA). Their thermal behavior was investigated by thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC), whereas scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transformed infrared (FTIR) were employed for analyses of their physicochemical and morphostructural properties. When compared to in natura samples, SEM images of the blends detected a structural disorder and a highly fibrous structure with an elongated chain and surface roughness. HHV were superior in samples with 100GCS (16.64 MJ kg−1), B75 (15.80 MJ kg−1), and B50 (14.98 MJ kg−1), and lower in B25 (14.16 MJ kg−1) and 100FS (13.03 MJ kg−1), with acceptable values for different biomasses. TG/DTG and DSC curves showed similarities among the samples, with the detection of their main thermoconversion stages. According to the data, the samples can be applied as renewable energy sources to mitigate socioecological illnesses and social vulnerabilities resulting from the archaic and inadequate management of solid waste.

Thermoanalytical techniques applied to the solid-state characterization of atorvastatin calcium trihydrate form I

Atorvastatin calcium trihydrate (ACT) is a synthetic lipid-lowering agent whose thermal character remains largely unknown or else mischaracterized due to being called both “atorvastatin” and “atorvastatin form I” indiscriminately in the literature. Developing stable drugs, however, requires ensuring and thus understanding the reliable thermal behavior of trihydrate drugs, for pharmaceutical manufacturing can involve temperatures that might cause phase transition and/or the dehydration of the drugs, with implications for its physical characteristics, its chemical characteristics, and/or the pharmaceutical product's bioactivity. Against that background, in our study we investigated both a solid-state and thermal characterization of ACT via powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hot-stage microscopy (HSM), and ex situ variable temperature PXRD techniques, all as integral parts of drug development. DSC and TGA curves clarified ACT's thermal stability and dehydration, and the ACT sample was identified as Form I of the trihydrate, which remains stable until approximately 40 °C. DSC showed no significant changes during melting with different heating rates, while the TGA curve revealed the stepwise loss of water molecules following heating. Ex situ PXRD suggested no abrupt changes to the trihydrate's crystal lattice during the dehydration of the first two moles of water molecules. Moreover, HSM clearly showed a unique water loss event never before visualized. Last, HSM confirmed the drug's crystallinity, its crystal shape, and the presence of an isotropic liquid after continuous heating, which remained until cooling to room temperature.

Preparation of Edible Colorant Lake Using Calcium Carbonate and β-Carotene: Structural Characterization and Formation Mechanism Study.

This study prepared a novel β-carotene colorant lake using calcium carbonate (CaCO3) and investigated the lake formation process and its basic characteristics. Kinetic adsorption analysis confirmed that medium pH (9.3) and medium temperature (40 °C) were more suitable for lake preparation, while desorption occurred, possibly due to crystalline transformation of CaCO3. The isothermal analysis and model fitting results suggested that the β-carotene and CaCO3 particles combined via a monolayer adsorption process driven by physical force. Electrostatic attraction likely participated in the process due to the net negative surface charges of β-carotene dispersion and positively charged groups on the CaCO3 particle surfaces. Ethanol, ultrasonic treatment, and drying method significantly influenced the immobilization efficiency (IE) of β-carotene in the lake and light stability of the lake, without affecting its crystal form. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curves confirmed absorption of β-carotene onto CaCO3. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated no obvious chemical bonds between β-carotene and CaCO3. Energy-dispersive spectroscopy (EDS) confirmed the presence of β-carotene on surfaces but not in the interior of the CaCO3 particles. The adsorption of β-carotene by calcium carbonate was further confirmed to be a physical adsorption on surface.

Effects of wheat flour levels on the thermal curing behavior of Urea–Formaldehyde and Phenol–Formaldehyde resins

Urea–formaldehyde (UF) and phenol–formaldehyde (PF) resins are the most prevalent adhesives in the manufacturing of wood composites, and they are cured by hot pressing to build a three-dimensional network structure in the composites. UF and PF resins are typically formulated with organic fillers like wheat flour to control viscosity and reduce costs in the commercial production of plywood. Although this formulation is well established, research on the effect of filler on the curing behavior of UF and PF resins has been insufficient. Therefore, this study used differential scanning calorimetry (DSC) to examine the influence of wheat flour as a filler in varying amounts on the thermal curing behavior of UF and PF resins. The results demonstrated that the viscosity and solid content of the UF and PF resins increased as the filler amount increased. In contrast, the gelation time, which reflected the curing speed of the resins, decreased as the filler content increased. Similarly, DSC results demonstrated that with increased filler amounts, the curing reaction of UF resins accelerated, as evidenced by a decrease in the apparent activation energy (Ea) determined using the Kissinger–Akahira–Sunose and Vyazovkin methods. However, in the case of PF resins, the average Ea increased and subsequently declined when 10% and 20% fillers were added. This demonstrated the complicated interaction between wheat flour and resins, particularly PF resins. Furthermore, the isothermal DSC curves reveal that the highest exothermic peaks of UF resins are observed at different isothermal temperatures as the filler amount increases. In contrast, PF resins maintain an isothermal temperature for the highest exothermic peaks across all filler levels. In addition, FTIR analysis suggested that wheat flour might contribute to the curing reaction of UF and PF resins.

Sm2O3 micron plates/B4C/HDPE composites containing high specific surface area fillers for neutron and gamma-ray complex radiation shielding

In this study, a series of Sm2O3 micron plates/B4C/HDPE composites composed of synthesized Sm2O3 fillers (Sm2O3 micron plates) are prepared for shielding neutron and gamma radiation. The influence of micromorphology of Sm2O3 fillers on neutron and gamma radiation shielding properties of composites is investigated in detail. The XRD pattern reveals that the phase of synthetic Sm2O3 is cubic crystal systems, body-centered cubic lattices, and its space group is Ia 3‾ (206). SEM images and BET analyses reveal that the micromorphology of synthesized Sm2O3 is micron plates. The BET-specific surface area of the Sm2O3 fillers is increased with addition of urea content. The differential scanning calorimetry (DSC) curves reveal that Sm2O3 fillers increase the melting temperature of the composites, which is up to 138.6 °C. The thermogravimetric analysis (TGA) results reveal that the initial thermal degradation temperatures of the composites are all above 440 °C. The neutron and gamma radiation shielding tests show that Sm2O3 fillers with high BET-specific surface area (8.20 m2/g) and uniform size improve the neutron and gamma shielding rate of composites. A superior composite containing 10 wt% Sm2O3 (R = 1:25, R value represents the molar ratio of rare earth elements to urea)/20 wt% B4C/70 wt% HDPE has a neutron radiation shielding rate of 98.7% with a thickness of 15 cm under the 252Cf neutron source and a gamma radiation shielding rate of 72.1% with a thickness of 15 cm under 137Cs gamma source. And these lead-free and environment-friendly composites can be widely used in the neutron and gamma complex radiation fields.

The Influences of Agglomeration and Storage on the Thermal Properties and Stability of Fats in Infant Formulas

The Influences of Agglomeration and Storage on the Thermal Properties and Stability of Fats in Infant Formulas

Tailoring the performances of Ti-V-Al base shape memory alloys by defects engineering

In the present study, various defects such as dislocations were controlled in Ti-V-Al-based shape memory alloy by thermomechanical treatment and introduction of interstitial oxygen (O) atom to optimize the performances. The results revealed that the Ti-V-Al-O shape memory alloys gradually evolved from α” martensite phase to the β parent phase with increasing annealing temperature. Moreover, the degree of lattice distortion can be tailored by changing annealing temperatures. Upon the annealing temperature reached 900 °C, masses of ω precipitates and a nano-sized ordered domain, characteristic of strain glass, can be found. As a result of suppression effect of multiple varieties of defects to the martensitic transformation, no obvious endothermic and exothermic peaks were observed in differential scanning calorimetry curves. The yield strength and maximum tensile fracture strength of the Ti-V-Al-O shape memory alloy increased with the increase of annealing temperatures. Meanwhile, Ti-V-Al-O shape memory alloys annealed at 900 °C possessed superior strain recovery characteristics and corrosion resistance. The excellent performances in Ti-V-Al-O shape memory alloys annealed at 900 °C can be attributed to the formation nanoscale nanodomain.