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Synthesis, structural and photoluminescence studies of p-(n-heptyl) benzoic acid (7ba) liquid crystalline (LC) compound with the homogeneous dispersion of ZnO nanoparticles (NPs) in different weight concentrations (i.e., 1–2.5 wt.%) were undertaken. The synthesized samples were subsequently characterized by different characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-Vis) spectroscopy, differential scanning calorimetry (DSC), optical polarising microscopy (POM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy. From the XRD studies, the diff raction peaks observed were well resolved indicating the presence of ZnO NPs. The particle size was found to be 60 nm. SEM studies revealed the uniform dispersion and the presence of ZnO NPs in the LC samples. From the DSC analysis, the temperatures at which the phase changes take place and the corresponding enthalpy values were estimated. FTIR spectra gave information about the various functional groups present in the samples. PL studies showed the peak at 663 nm due to the presence of point defects within the bandgap-like vacancies and interstitials known as deep-level emission. [ABSTRACT FROM AUTHOR]

Background: In advanced or metastatic cancers characterized by specific genetic alterations, heightened growth and resistance to conventional therapies are common. Targeted treatments like entrectinib (ENT) precisely inhibit aberrant signaling pathways, potentially enhancing outcomes. The objective of this research is to develop and enhance the effectiveness of entrectinib-loaded nanosponge formulations by utilizing hydroxypropyl-β-cyclodextrin (HPβCD) to improve its oral bioavailability. Results: The study employed surface response methodology and Design-Expert® software to optimize key formulation variables such as the molar concentration ratio of the polymer and cross-linker, as well as process variables such as stirring speed and duration. Optimization focused on particle size, polydispersity index, and percentage entrapment efficiency. Validation methods encompassed Fourier transform spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), in vitro release studies, and in vivo studies. After optimization, ENT-loaded HPβCD NSPs were formulated with a molar ratio (P:CL) of 0.800 mg, stirred at 3000 rpm for 420 min, achieving a desirability of 0.926. Predicted values for PS (particle size), PdI (polydispersity index), and EE % (entrapment efficiency) were 146.98 nm, 0.263, and 88.29%, respectively. The optimized formulation showed a mean size of 151.8 ± 5.6 nm, PDI of 0.233 ± 0.049, and EE of 87.36 ± 1.61%. Further validation through various analyses confirmed the optimization's efficacy, with notable improvements demonstrated in AUC0-t (6.30-fold) and Cmax (4.10 times) compared to the free drug. Conclusion: The findings of the study indicated that nanosponges exhibit promise as an effective carrier for delivering entrectinib, addressing for advance tumor effectively by enhancing release and bioavailability in the treatment of cancer. Highlights: Entrectinib (ENT) is an innovative and powerful inhibitor targeting specific genetic alterations in advanced or metastatic cancers. Preclinical investigations have shown strong suppression of receptor tyrosine kinases, such as TRKA/B/C and ROS1, at nanomolar (nM) concentrations using ENT. ENT is categorized under the Biopharmaceutical Classification Systems (BCS) II, with poor solubility and inadequate oral bioavailability. Formulation of ENT HPβCD based nanosponges (NSPs) present a compelling option for drug delivery due to their sustained drug release, enhanced stability, and significant carrying capacity. [ABSTRACT FROM AUTHOR]

The main theme of the paper was focussed on the preparation, structural, optical, and photoluminescence studuies of p(-n-decyloxy) benzoic acid (10OBA) liquid crystalline (LC) compounds with 1 wt.% dispersed ZnO nanoparticles (NPs). The prepared samples were subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical polarizing microscopy (POM), differential scanning calorimetry (DSC), UV-Visible spectroscopy, and photoluminescence (PL) studies. From the XRD, the diffraction peaks observed at 36.2, 42.5, 61.3, and 73.2° were well resolved, indicating the presence of ZnO NPs and the particle size was found to be 65 nm. SEM studies revealed the uniform dispersion and the presence of ZnO NPs in the samples. The textural images of different phases (nematic, smectic) of liquid crystalline compounds of 10OBA pure and 10OBA with 1 wt.% dispersed ZnO NPs were observed through the POM with reduced temperature. From the DSC thermograms, the phase transition temperatures and the correponding enthalpy values were estimated. The bandgap reduces for 10OBA LC compound with the dispersion of 1 wt.% ZnO NPS and it is estimated as 3.25 eV compared with 4.25 eV for the undoped 10OBA LC compound. PL studies showed the presence of the peak at 616 nm owing to the presence of point defects within the bandgap-like vacancies and interstitials known as deep-level emission. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) is a type of cancer that affects the colon or rectum and occurs in individuals over the age of 50, although it can affect people of all ages. Quercetin is a flavonoid, which is a type of plant pigment with antioxidant and anti-inflammatory properties. Some studies have explored the potential of quercetin as an adjuvant therapy to enhance the effectiveness of chemotherapy or radiation therapy. Methodology: In the proposed work, the nano-biomaterials of solid lipids such as stearic acid (SA) and tripalmitin (TpN) as well as the surfactants tween 80 and span 80 were used to prepare novel quercetin (QuR)-loaded-solid lipid nanoparticles (QuR-SLNs) for medical applications in colorectal cancer (CRC). The resulting bio-nano SLNs' mean entrapment efficiency (EE) and particle size (PS) were optimized by Box–Behnken design (BBD) approach based on the response-like surface methodology (RSM). The variables include lipid ratio (X1), surfactant ratio (X2), QuR-to-lipid ratio (X3), the sonication time (X4), and the homogenization time (X5). Requirements on the maximum EE (%) and minimum PS (nm) were optimized for the preparation of QuR-SLN. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) were then used to analyze the optimized SLN and to find the crystalline state of QuR with lipid relationship. In addition, on the Caco-2 cells, at IC50 (49 µM/mL), in vitro cytotoxicity was attained. Results: The optimized QuR-SLN had practically spherical shapes, with % EE and a PS of 97.8 ± 1.16% and 132.16 ± 4.1 nm, respectively. In aqueous media, the degree of lipid crystallinity and the lipid modification was investigated, and the QuR incorporation and release patterns showed high correlations with both. The results showed that over 41.12 ± 1.6% of the bio-nano QuR-SLNs was released gradually over the course of 48 h, demonstrating effective QuR delayed release. Results on apoptotic observations indicate that apoptosis accounts for the majority of cell death, while necrosis, a type of cell death, constitutes a very minor portion. In conclusion, the prepared bio-nano QuR-SLNs might improve cytotoxicity and can act as an ideal carrier for the delivery of QuR and this preparation is used in the treatment of CRC. [ABSTRACT FROM AUTHOR]

To address the issue of low mechanical strength in self-supported hollow fiber membranes, a research study was conducted to fabricate polysulfone braid-reinforced hollow fiber (PSF BRHF) membranes for natural gas purification. In this study, polyethylene (PET) was used as a braid support. PSF BRHF membranes were fabricated by employing dip coating and drying technique. The BRHF membranes underwent comprehensive analysis, including the manipulation of polymer (PSF) concentration (15 wt%, 18 wt%, and 21 wt%) and the number of coating layers (1–4). Characterization of the fabricated membrane samples involved scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gas separation performance testing, and mechanical strength testing. The results indicated that membranes fabricated with higher polymer concentrations exhibited a denser structure with a thicker separation layer. An increase in the separation layer thickness was also observed with an increasing number of coating layers. Importantly, all fabricated membrane samples demonstrated remarkable thermal stability. To assess the performance, gas separation tests were conducted using pure gases at 3 bar. Notably, the membrane sample with 21 wt% PSF and the 3rd coating layer (21_3 PSF) exhibited the most promising gas separation performance among all the samples selected to carry out the separation performance test, achieving a CO2/CH4 selectivity of 1.83. Mechanical strength testing revealed that 21_3 PSF BRHF (68.2 MPa) fabricated in this study outperformed conventional self-supported PSF hollow fiber membranes (9.44 MPa), as reported in the literature. These findings underscore the potential of BRHF membranes for natural gas purification, although further improvements are still possible. [ABSTRACT FROM AUTHOR]

An innovative approach to build a high-performance, thermally stable Al-8Ce-10Mg (wt.%) alloy via friction-stir based solid-state additive manufacturing, called additive friction stir deposition, has been demonstrated in this study. The deposited material displayed 22% higher yield strength and 181% improvement in ductility as compared to the base material. The deposit also exhibited excellent tensile properties at elevated temperatures. The improved performance has been attributed to multiple strengthening mechanisms active in the built component. Al-Ce particle fragmentation, grain refinement, and retention of Mg in solid solution during the process synergistically resulted in the improved mechanical performance. The fragmentation of Al11Ce3 particles occurred due to intense frictional heating and shearing during the process. Scanning electron microscopy, nanoindentation, tensile testing, differential scanning calorimetry, and X-ray diffraction analysis were used to establish process–structure–property correlations at multiple length scales. [ABSTRACT FROM AUTHOR]

Background: The objective of the present investigation was to obtain directly compressible agglomerates of ibuprofen with nicotinamide by a quasi-emulsification solvent diffusion technique. Ibuprofen-nicotinamide agglomerates were prepared by quasi-emulsification solvent diffusion technique using ethanol (good solvent), water (poor solvent), and chloroform (bridging liquid). The prepared agglomerates were characterized by ATR-FTIR, powder X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy and were evaluated for tableting performance and in vitro drug release. To appropriately identify the hydrogen bonding sites, a thorough understanding of the structures of API and coformer is necessary, hence molecular docking approach was implemented to depict the interaction between the proposed coformer and COX-2 protein (PDB Id:4PH9). Results: The percent yield of agglomerates was in the range of 85–98 w/w%, and drug content for all batches was in the range of 96–99%. The microphotographs showed irregular circularly shaped agglomerates. ATR-FTIR study showed a strong possibility of hydrogen bonding between ibuprofen and nicotinamide. The crystallinity of ibuprofen was slightly reduced and confirmed by P-XRD and DSC. Crushing strength and friability studies showed good handling qualities of ibuprofen agglomerates. Heckel plot studies showed low mean yield pressure and high tensile strength, indicating excellent compressibility and compactibility of ibuprofen agglomerates. More than 90% drug release was obtained within 60 min in PBS (pH 7.4). The docking studies revealed that nicotinamide individually has –CDOCKER energy 16.8109 where coformer showed 29.0584, which indicates coformer has a better binding affinity to target as compared to nicotinamide individual. Conclusions: It can be concluded that the agglomerates improved the dissolution, tableting performance, and solid-state properties of ibuprofen and hence can be useful to improve the therapeutic performance of ibuprofen. [ABSTRACT FROM AUTHOR]

Hollow sphere polymeric pigments prepared from styrene-acrylate copolymer referred to as organic opacifiers (OP) are the primary substitutes of TiO2 in water-based architectural paints. This study describes the method for the quantification of OP in water-based paints using dynamic mechanical thermal analysis (DMTA). The significance of DMTA in visualizing the glass transitions over differential scanning calorimetry (DSC) is showcased. The glass transition temperature (Tg) of OP was found to be ~109°C by DSC method and ~125°C by DMTA method. The peak intensity of tan δ at Tg of OP in paints (tan δ2) is not affected by the curing time and linearly increases as a function of OP concentration in water-based paints, irrespective of the difference in volume solids. DMTA can efficiently quantify OP in paint film if it is ≥3.3% (w/w). Increasing concentration of a coalescing solvent in water-based paints has a detrimental effect on the peak intensity of tan δ2. Two commercially available grades of OP having difference in the core-shell morphology have been studied. Internal morphology of the OP studied by scanning electron microscopy has a significant effect on the peak intensity of tan δ2 thereby affecting its opacity performance in paints. Owing to the limited effect of curing time, volume solids and coalescing solvent on the peak intensity of tan δ2 of paints, this method can be used for the quantification of OP in paints, as it has been validated with seven commercially available paints with known OP contents. [ABSTRACT FROM AUTHOR]

Present research focused on polymeric fractions of two wheat varieties' (DBW88 and HI1500) evaluation for molecular weight and HMW-GS composition using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), degree of crystallinity using X-ray diffraction, microstructural assessment through scanning electron microscopy (SEM), for thermal profiling using differential scanning calorimetry (DSC) and secondary structure analysis employing Fourier transform infrared (FTIR) spectroscopy technique. Glutenin fractions were identified into high molecular weight (HMW) glutenin fractions (140 kDa to 75 kDa) and low molecular weight (LMW) glutenin fractions (45 kDa to 30 kDa) as per SDS-PAGE for both varieties. XRD results displayed amorphous nature of all extracted polymeric protein fractions. SEM results revealed dense stranded structure in gluten matrix due to the addition of polymeric wheat protein and its further subfractions with subtle variation. Thermal stability of glutenins of both varieties DBW88 (161.95 °C with 808.48 J/g) and HI1500 (160.64 °C with 785.57 J/g) were observed to be highest due to highly ordered structure, followed by HMW glutenins, gluten and LMW glutenins in case of DBW88 while LMW glutenins, gluten and HMW glutenins in case of HI1500. Highest proportion of β-sheets and β-turns was observed in HMW glutenins of DBW88 and LMW glutenins of HI1500. [ABSTRACT FROM AUTHOR]

In this study, 2-[(E)-(hexylimino)methyl] phenol (SA-Hex-SF) was synthesized by adding salicylaldehyde (SA) and n-hexylamine (Hex-NH2), which was subsequently reduced by sodium borohydride to produce 2-[(hexylamino)methyl] phenol (SA-Hex-NH). Finally, the SA-Hex-NH reacted with formaldehyde to give a benzoxazine monomer (SA-Hex-BZ). Then, the monomer was thermally polymerized at 210 °C to produce the poly(SA-Hex-BZ). The chemical composition of SA-Hex-BZ was examined using FT-IR, 1H, and 13C NMR spectroscopy. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray Diffraction (XRD), respectively, were used to examine the thermal behavior, surface morphology, and crystallinity of the SA-Hex-BZ and its PBZ polymer. Mild steel (MS) was coated by poly(SA-Hex-BZ) which was quickly prepared using spray coating and thermal curing techniques (MS). Finally, the electrochemical tests were used to evaluate the poly(SA-Hex-BZ)-coating on MS as anti-corrosion capabilities. According to this study, the poly(SA-Hex-BZ) coating was hydrophobic, and corrosion efficiency reached 91.7%. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WBPUR) aerogels using acetone method and freeze-drying procedure have been successfully synthesized. The morphology, chemical structure, and thermal and mechanical properties of obtained aerogels were analysed by means of scanning electron microscopy, Fourier-transform infrared spectroscopy, contact angle, thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical analysis. In addition, the influence of the solids content in the hydrogel (2–15 wt.%), obtained by varying the amount of water added in the suspension, on the density and thermal conductivity was evaluated. Obtained results demonstrated that the properties of aerogels strongly depend on the solids content assayed in the parent solution. As the solids content in the WBPUR aerogels increases, the density and thermal conductivity for materials with 2.5 and 10% solids content follow an upward trend, while their elasticity decreases. Materials with solids content below 2.5% and above 10% have not demonstrated adequate processability due to their high deformity and hardness, respectively. The drying methodology (freeze-drying) can be profitably used to prepare aerogels-like materials in a cost-effective way. Illustration of the alternative preparation process of WBPUR aerogels and its potential industrial application. [ABSTRACT FROM AUTHOR]

In this work, synthesis and phase stability of a novel dual-phase (HCP–BCC) AlCoTiZn high-entropy alloy are presented. Microstructural evolution and thermal stability of the alloy powder were studied up to their melting point. X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, atomic emission spectrophotometry analysis and hardness measurements were used for the characterization of the HEA. As-milled and the bulk samples consist of an HCP and Co-rich BCC dual phases. The samples heat-treated at intermediate temperatures show HCP and Co-rich two FCC phases. Thermal stability studies reveal that vaporization of Zn occurs at around 800 °C. An extraordinary hardness of 1005 ± 50 HV was observed in the bulk sample. This is mainly attributed to the presence of dual-phase HCP–BCC structures. [ABSTRACT FROM AUTHOR]

Clear asphalt (CA) currently used in light-colored asphalt mixtures (LCAM) exhibits poor transparency and adhesion. Therefore, a highly transparent CA (HCA) modified using a silane coupling agent (KH550) was prepared. Furthermore, LCAM was prepared by mixing CA and limestone aggregates. The properties of the HCA and ordinary CA (OCA) were characterized using conventional asphalt tests, optical tests, pull-off tests, ultraviolet aging tests, dynamic shear rheometry, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and scanning electron microscopy. Whereas Marshall, moisture resistance, wheel tracking, trabecular bending, and British pendulum tests were employed for the LCAM. The transmittance and spectral reflectance of the HCA were 123.30 and 3.74 times greater than those of the OCA, respectively. The complex modulus and viscosity-aging index of the HCA were 48% and 53% less than those of the OCA, respectively. After modification with KH550, the Marshall stability ratio, tensile strength ratio, and flexural strain of the HCA-prepared LCAM increased by 12.92%, 25.06%, and 23.90%, respectively. However, the rutting resistance of the HCA-prepared LCAM was 14.3% less than that of the OCA-prepared LCAM. The comprehensive performances of the HCA and HCA-prepared LCAM were 49.2% and 10.3% greater than those of the OCA and OCA-prepared LCAM, respectively, indicating a high application value in the future. [ABSTRACT FROM AUTHOR]

FeSiCr/MnZn ferrite composites with low permittivity were prepared by a two-step synthesis method, which can improve the absorbing property of the material. The phase and thermal behavior of the composites were analyzed by x-ray diffractometry, thermogravimetric analysis/differential scanning calorimetry. The morphology was studied by scanning electron microscopy. The soft magnetic properties and electromagnetic parameters of the material were tested by a vibrating sample magnetometer and a vector network analyzer. The results show that, compared with pure FeSiCr powders, the complex permittivity of a FeSiCr/MnZn ferrite composite was significantly decreased, while the complex permeability was slightly decreased, achieving a more ideal impedance matching. When the MnZn ferrite content is 15% and the simulated thickness is 2 mm, the minimum reflection loss (RL) of the sample reached − 27.4 dB at 10.4 GHz, and the bandwidth reached 5.0 GHz when RL exceeded − 10 dB. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles (NPs) are used in many electro-optical applications due to their special characteristic properties. NPs improve the optical parameters of liquid crystalline molecules. The main theme of this paper focuses on the homogeneous dispersion of ZnO NPs in small concentrations, i.e. 1, 1.5, 2, and 2.5 wt% in liquid crystal compounds of p-n-octyloxy benzoic acid (8oba). Scanning electron microscopy is used to ascertain the morphology of the dispersed ZnO NPs in liquid crystal compounds. Polarizing optical microscopy and differential scanning calorimetry are used to determine the phase transition temperatures of these compounds. The wedge-shaped modified spectrometer is used to determine the refractive indices at different wavelengths, visually 460, 500, 570, and 635 nm. The values of the birefringence (δn) and order parameter (S) are enhanced with the dispersion of increasing concentrations of ZnO NPs. [ABSTRACT FROM AUTHOR]

The kinetics of formation and crystallization of Ln2Ti2O7 (Ln = Gd, Lu) pyrochlores from nanoparticulate precursors prepared via coprecipitation have been analyzed using X-ray diffraction, Raman spectroscopy, luminescence spectroscopy, scanning electron microscopy, calorimetry (differential scanning calorimetry (DSC)), mass spectrometry, and quantitative thermogravimetry (TG). The results demonstrate that the formation of the pyrochlores proceeds through crystallization of a nanoparticulate fluorite phase. The starting mixtures have been shown to consist in considerable measure of hydroxides and hydroxycarbonates, rather than of oxides. The first synthesis step at temperatures below 550–650°C is decomposition of the starting compounds to titanium oxide and lutetium (or gadolinium) dioxycarbonate. The second step is the synthesis of final compounds, also accompanied by CO2 release. Thus, "high-temperature" CO2 release makes it possible to visualize the synthesis kinetics. Specially designed experiments involving prolonged heat treatment at low temperatures (540 h at 550°C and 216 h at 700°C) have shown that Lu2Ti2O7 can be synthesized almost completely from starting mixtures even at 550°C. The high degree of conversion at 550°C has been confirmed by quantitative TG. Raman and luminescence spectroscopy results demonstrate that the disordered nanooxide synthesized at 550°C, with a crystallite size of 15 Å, has the fluorite structure. Prolonged heat treatment at 700°C was accompanied by an increase in crystallite size and a fluorite-to-pyrochlore phase transition. During heating of the starting precursor at a high rate, 10°C/min (DSC and TG), all of the processes were shifted to higher temperatures. The formation of the final Ln2Ti2O7 (Ln = Gd, Lu) pyrochlores through a nanoparticulate fluorite phase is characteristic of both systems. Thus, all of the Ln2M2O7 (M = Ti, Zr, Hf) 3+/4+ pyrochlores are formed as a result of an order–disorder transition from a nanoparticulate fluorite phase to a pyrochlore phase. [ABSTRACT FROM AUTHOR]

In this work we investigated the possibility of substituting diphenylamine (DPA) by the natural product 2-methoxy phenol, known as guaiacol (CAS 90-05-1), as a stabilizer for nitrocellulose (NC)-based propellants. Stability evaluation, using heat flow calorimetry, revealed lower heat flows associated with our guaiacol-stabilized propellant samples when compared to those of propellants stabilized with the traditional stabilizers. Also, pressure vacuum stability tests showed that our propellant exhibited lower evolved gas volumes. Traditional tests, such as the German Test, and the Bergmann-Junk Test, scored a NO volume, after titration, of 0.87 ml (below the limit-value for acceptance, which is 2.0 ml), and the Storage Test, showed that our samples are stable and do not degrade until 3 days when submitted to a constant temperature of 100 °C. The homogeneity, stability and compatibility of our samples were evaluated through scanning electron microscopy, differential scanning calorimetry, and isothermal thermogravimetry. Ballistic parameters were estimated using a closed vessel along with computational codes developed by our research group, for comparison purposes. Finally, the high-performance liquid chromatography method allowed inferring the stabilizer consumption after artificial ageing of samples. This method also showed that the material met the corresponding stability criteria of AOP-48. Concluding, our results clearly indicate that guaiacol is an effective and efficient substitute for DPA as a propellant stabilizer for single-base NC-based propellants, making them more environmentally friendly. [ABSTRACT FROM AUTHOR]

Integrating energetic materials with microelectromechanical systems (MEMS) to realize miniaturized energetic chips has shown broad application prospects in micro-spacecraft, micro-satellites, ballistic correction munitions, and smart munitions. In this work, a new type of MEMS compatible Cu/ICM-101 energetic film was successfully fabricated on copper substrates by in-situ electrochemical synthesis, the morphology and ignition property of which can be effectively controlled by adjusting the voltage and electrochemical deposition time. The morphology, composition, thermal properties, and ignition performance of as-prepared Cu/ICM-101 films were characterized by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and pulsed laser. The results show that the as-prepared Cu/ICM-101 films possesses nano porous framework structure with an exothermic heat of 1800.9 J·g−1 and a thermal decomposition peak temperature of 256.4 °C. In addition, the flame height and ignition duration of which reach 10 mm and 300 μs, respectively. This work provides a reference for the integration and application of energetic materials in MEMS systems. [ABSTRACT FROM AUTHOR]

Aluminum, boron, and magnesium are one of the most common aerospace infrastructure materials. Therefore it is important to know their effectiveness in radiation shielding. In this study, Al–B–Mg powder alloy with a nominal composition of Al50B25Mg25 was synthesized by using a mechanical alloying (MA) process under an argon gas atmosphere for potential use as a aluminum based engineering material. Microstructural evolution, thermal behaviour, and mechanical properties of the mechanically alloyed powders as a function of milling time were investigated by means of X-ray diffraction (XRD), differential scanning calorimetry, transmittance electron microscopy and scanning electron microscopy (SEM). The XRD and SEM results revealed that the microstructure of the powders materials changed during MA. The crystallite size of Al–B–Mg powders decreased with increasing milling time. The average crystallite size was determined. The results also showed that after 100 h of milling time nanostructured α-Al (Mg, B) solid solution phase whose crystallite sizes are below 17 nm were obtained. Also, radiation shielding parameters have been investigated using NaI (Tl) γ-ray spectrometry at 662 and 1173 keV energies obtained via 137Cs and 60Co radioactive point sources. The obtained experimental data have been compared with XCOM theoretical data. The experimental data was utilized to calculate the half-value layer, tenth-value layer, and mean free path values. According to the obtained data, Al50Mg25B25 alloy powder prepared and annealed at 300 °C has been shown to provide better protection against radiation. [ABSTRACT FROM AUTHOR]

The aim of the present study was to formulate clindamycin (CLN) as a microsponge based gel to release the drug in a controlled manner and reduce the side effects in the treatment of acne. Since this method requires poor water solubility of the drug to be loaded in particles, therefore, conversion of the hydrochloride salt to free base was done. By using an emulsion solvent diffusion method, we made six different formulations of microsponges containing CLN-free base by changing the proportions of polymer, emulsifier and the pH of the external phase. These formulations were studied for physical characterization and for drug- polymer interactions. The physical characterization showed that microsponge formulations coded by C5, C6 resulted in a better loading efficiency and production yield and their particle size was less than 30 µm. Scanning electron microscopy images showed the microsponges porous and spherical. C5, C6 microsponge formulation was prepared as gel in Carbopol and in vitro evaluated. The microsponge formulation gel C8 was found to be optimized. C8 released 90.38% of drug over 12 h and showed viscosity 20,157 ± 38 cp, pH of 6.3 ± 0.09 and drug content of 99.64 ± 0.04%. Fourier transform infrared spectroscopy and differential scanning calorimetry confirmed no significant interactions between excipients and drug. [ABSTRACT FROM AUTHOR]

Repaglinide, a member of the meglitinide class of drugs, is a new anti-diabetic agent that is utilized as an oral hypoglycemic agent. Using glyceryl monostearate, cetyl palmitate, and tristearin as lipids and poloxamer 188 as a surfactant, repaglinide-loaded solid lipid nanoparticles were created. Solid lipid nanoparticles were prepared utilizing an o/w microemulsion technique, which included the lipids glyceryl monostearate and tristearin, as well as waxes such as cetyl palmitate and the surfactant poloxamer 188. The mean particle size of the solid lipid nanoparticles formed was around 339 nm, with an entrapment efficiency of 82.20%. In-vitro release studies continued to be conducted using the dialysis bag diffusion technique. Within 12 h, the cumulative drug release was 88.4%. The results indicate that repaglinide was released more slowly from solid lipid nanoparticles made from tristearin and glyceryl monostearate in an equal ratio. Tristearin found the controlled release and extreme entrapment from other lipid carriers like glyceryl monostearate and cetyl palmitate. Differential scanning calorimetry demonstrates that repaglinide is entangled in amorphous or molecular state within solid lipid nanoparticles. SEM microscopy revealed that the produced repaglinide solid lipid nanoparticles had a spherical shape. After one month of storage at 2–8 °C, short-term stability testing revealed no significant alteration. [ABSTRACT FROM AUTHOR]

The present study investigates experimentally phase equilibria relations in the B-Fe-W ternary system. For the experimental study, B-Fe-W alloys were produced by arc-melting. These alloys were equilibrated using long-term annealing for 2000 h and 4224 h at temperatures of 1050 and 677 °C, respectively. The alloys were characterized by scanning electron microscopy coupled with energy dispersive x-ray spectroscopy, x-ray powder diffraction analysis, and differential scanning calorimetry. Based on the experimental results, the B-Fe-W system was modeled using the CALPHAD method. Herein, boron was modeled interstitially in the solid solutions of iron and tungsten. Also, in this study, the volume phase fractions for selected B-Fe-W alloys were determined using an image analysis technique. [ABSTRACT FROM AUTHOR]

Three different compositions of bulk Ni-Ti samples fabricated by laser additive manufacturing technique are subjected to laser shock peening with multiple shots of 1 GW/cm2 irradiance. A numerical simulation is implemented to predict the amount of residual stress to be generated on the sample surface to optimize the processing parameters. The experimental results reveal the number of shots to be three, in order to achieve the desired amount of residual stress from the chosen power density for processing. LSP yields a total increase in the residual stress by 40-45% on the surface of the samples. To investigate the nature of samples, after LSP several characterizations are done to study the mechanical, microstructure, phase transformation and crystalline properties. The scanning electron microscopy images reveal the surface morphology of the samples, to be roughened in nature by the effect of LSP. Also, the enhancement in the microhardness by 20% vividly shows improvement in the mechanical properties. X-ray diffraction shows a substantial fluctuation in peak intensity and peak positioning post LSP. The peak diminishing is observed after LSP in the XRD graph, which confirms the amorphization induced in the samples. Differential scanning calorimetry shows an increase in the phase transformation temperature by 20-30 °C for the NiTi50 sample. The study reveals the composition of NiTi50 fabricated by LAM was able to sustain the pressure generated by LSP by withholding its physical and chemical nature. [ABSTRACT FROM AUTHOR]

Smart fiber is the most amazing material which can be employed for various applications. In the present work, we report the modification of cotton thread by coating it with the copolymer poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) known for its high conductivity along with ethylene glycol (EG), which lowers the corrugation of the cotton thread. The process of the coating was carried out by dipping and drying, which increased electrical conductivity. The modified thread yielded cotton thread with resistance value (i.e., 0.007286 Ω−2) much lower than that of the cotton thread (CT), similar to the metals. The structural characterization of the prepared composite was carried out by various techniques such as scanning electron microscopy attached with energy-dispersive x-ray analysis (SEM–EDX), Fourier-transformation infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analysis. [ABSTRACT FROM AUTHOR]

For the first time, Nd-MOF nanostructures were synthesized using a novel ultrasonic procedure. The final products were characterized by relevant techniques of X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, energy-dispersive X-ray mapping analysis, nuclear magnetic resonance, vibrating sample magnetometer, photoluminescence, and Brunauer–Emmett–Teller (BET) surface area analysis. Results showed that using ultrasonic irradiation can produce Nd-MOF samples with desirable physicochemical properties. It was found that the Nd-sample synthesized in optimum conditions has a high surface area of 1649 m2 g−1. This value expands the application of these novel materials in different fields such as electrochemical applications. The electrochemical cyclic voltammetry method was employed to study the behavior of DA on the proposed modified electrode. The results revealed high yields of these compounds in the electrooxidation of dopamine. The efficient synthesis route, novel physichochemical properties, and potential electrochemical applications developed in this study can be used as a novel protocol for other MOFs. [ABSTRACT FROM AUTHOR]

Non-isothermal crystallization kinetics of polypropylene (PP)/polytetrafluoroethylene (PTFE) fibrillated composites is presented. In-situ fibrillated PP/PTFE-composites containing 1 and 3 wt% PTFE were prepared by melt compounding using a twin-screw extruder. The morphology and non-isothermal crystallization behavior of the composites were examined using scanning electron microscopy and differential scanning calorimetry, respectively. The Mo equation was used to analyze the kinetics of non-isothermal crystallization behavior. The PTFE created a three-dimensional (3-D) network. A low PTFE content promoted crystallization through fast nucleation, whereas a high PTFE content decreased the crystallization kinetics through hindering the crystal growth. These findings are all based on the Mo equation analysis. The activation energy and nucleation activity were also evaluated, and the way in which the PTFE nanofibers affected the crystallization was discussed in detail. Polarized optical microscopy images revealed that the size of PP spherulites decreased with the increase of PTFE content. Finally, the effect of PTFE on the crystalline phase of PP was investigated by wide angle X-ray diffraction. [ABSTRACT FROM AUTHOR]

The influence of the cooling rate on the precipitation behavior of gamma prime (γ′) in a newly developed Co-based superalloy has been investigated by using differential scanning calorimetry. In addition, changes to the γ′ precipitate morphology and size were analyzed by scanning electron microscopy. It was observed that increasing the rate at which the alloy was cooled from high temperatures increased the γ′ precipitation rate at different temperatures but also reduced the temperature at which the maximum precipitation rate occurred and retarded the complete precipitation of the γ′ precipitates. The activation energy required for γ′ precipitation was calculated by using the Kissinger model, revealing that the present alloy exhibits higher activation energy than some Ni-based superalloys, which can be attributed to lower rates of atomic diffusion in cobalt-based superalloys. [ABSTRACT FROM AUTHOR]

Structural, optical, thermal, morphological and electrical features of pure blend and composites based on poly(ethyl methacralyte) (PEMA) and poly (methyl methacrylate) (PMMA) filled with different contents of cobalt chloride (CoCl2) and lithium bromide (LiBr) were investigated. The composite samples at various concentrations of mixed filler were prepared using the casting method. X-ray diffraction (XRD) showed an amorphous feature of the pure blend films. Fourier transform infrared (FT-IR) spectra depicted that components of the blend, PEMA and PMMA polymers, are miscible. Ultraviolet and visible (UV–Vis.) measurement revealed that the values of the optical energy gap are decreasing with increasing mixed filler concentrations. Scanning electron microscopy (SEM) after adding the mixed filler shows small granules and bright spots on the surface of the blend. Differential scanning calorimetry (DSC) results show that adding mixed filler to polymeric solution enhances their thermal stability. The plot of DC conductivity versus temperature shows the Arrhenius model (linear variation). [ABSTRACT FROM AUTHOR]

The phase equilibria in the La2O3-Yb2O3 system were investigated using differential thermal analysis, and the phase transformations temperatures were verified. Microstructure investigation using scanning electron microscopy confirmed the presence of eutectoid reactions in the system. The heat capacity of LaYbO3 with a perovskite structure was measured in the temperature range from 250 to 1250 K using differential scanning calorimetry. The experimental results of the present work as well as reliable literature data were used to derive a thermodynamic description of the La2O3-Yb2O3 system. Isothermal sections of the ZrO2-La2O3-Yb2O3 system were constructed based on x-ray and microstructural investigations. The tie-lines change from Pyrochlore + Yb 2 O 3 _ C to LaYbO 3 _ Perovskite + Fluorite was explained by a solid-state reaction occurring in the range between 1673 and 1873 K. The heat effect observed at 1858 K using DTA confirms the phase transformation, and its temperature was established more precisely at 1808 ± 15 K using stepwise heat treatment. [ABSTRACT FROM AUTHOR]

A microwave irradiation-based high-efficiency method was utilized in this study to prepare novel chromium (III) oxide (Cr2O3) nanostructures with their own distinctive properties. The synthesis method was accordingly conducted in optimum conditions for the time duration of 20 min, the power of 360 W, and the microwave temperature of 30 °C. The scanning electron microscopy (SEM) micrographs also revealed a highly homogeneous morphology of crystalline nanostructures. Besides, the X-ray powder diffraction (XRD) and the differential scanning calorimetry (DSC) data demonstrated the single-phase existence of these components. Thermal stability and development of pure Cr2O3 samples were further investigated by thermo-gravimetric analysis (TGA) and DSC. Moreover, the Brunauer–Emmett–Teller (BET) technique showed a high specific surface area and significant porosity of these materials. As well, value-stream mapping (VSM) was employed to test the magnetic characteristics of the products. The findings established that microwave irradiation could play a key role in the synthesis of Cr2O3 compounds in environmental conditions. The effective microwave-assisted route applied in this study for the synthesis of Cr2O3 nanocatalysts with high physico-chemical properties was also remarkable compared with other nanocatalysts. [ABSTRACT FROM AUTHOR]

Environmentally friendly finishing methods for imparting antimicrobial properties to various textiles are very desirable. The purpose of the present study is to investigate the synthesis, characterization, and application of various chitosan (Ch) derivatives containing Ag, Cu and Zn nanoparticles (NPS) on wool yarn. The Ch loaded with various NPs was studied by Scanning Electron Microscopy (SEM), Dynamic light scattering (DLS), Fourier Transform Infra-Red (FTIR) and Differential Scanning Calorimetry (DSC). Wool yarns were treated with Ch-NPs and the treated samples were analyzed by SEM. The weight gain results indicated the successful surface modification of wool fibers with Ch-NPs. The treated samples showed excellent antimicrobial activities (~ 100%) against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The treated samples had generally very high antimicrobial activities (> 80%) even after 10 washing cycles. The surface modification of wool fibers with Ch-NPs can be considered as an environmentally friendly method for antimicrobial finishing. [ABSTRACT FROM AUTHOR]

Epoxy composites are widely used in commercial products. For industrial purposes, storage stability is one of their most important characteristics. To enable this feature, alternative promoters that are stable at a low-energy state, where they do not react, are needed. Zeolitic imidazolate frameworks (ZIFs) are organic–inorganic complexes, and they contain imidazolate linkers, which are one of the promoters in the epoxy–amine reaction. In this study, the stability of a one-pot epoxy–amine composite was improved by using ZIFs as promoters. ZIFs were synthesized using the solvothermal method, and their structure were confirmed using X-ray diffraction analysis and field-emission scanning electron microscopy. The activation energy of the ZIFs was measured using the non-isothermal method of differential scanning calorimetry, and it was calculated using the Kissinger equation. Furthermore, the storage stability of the one-pot epoxy–amine system was measured considering the viscosity change with time at constant temperature. The viscoelastic behavior of the cured sample was demonstrated using dynamic mechanical analysis. [ABSTRACT FROM AUTHOR]

Thermal history is a key factor affecting mechanical properties of polymeric parts made by the selective laser sintering (SLS) process. In this research, the effect of thermal history on the mechanical properties of PA12 parts produced by the SLS process has been investigated. It is hypothesized that different cool-down methods (normal to very slow cooling) and built orientations, resulted from flat and edgewise layouts fabrication, could be influencing factors on the thermal history during the SLS process. The temperature changes at different points inside the powder bed were recorded during the fabrication of specimens. Afterward, the morphology of fabricated samples was examined using scanning electron microscopy. In addition, the degree of crystallinity and melting point of the parts were studied by differential scanning calorimetry analysis. It was found that the built orientation was more effective than the cooling methods on ultimate tensile strength (UTS) and elongation at break (EaB), so that UTS and EaB of the edgewise parts were 10%, 50% greater than the flat parts. On the other hand, the variation of crystallinity with cooling methods has been found to be much less than might be expected from the implemented various fabrication conditions. However, the applied slowest cool-down method slightly increased the edgewise parts crystallinity to 23%, compared to 19.2% for the normal cooled down samples, leading to greater UTS than the normal cooled specimens. The morphology observation of specimens fracture surfaces suggests that better mechanical performance of the edgewise samples is likely connected to fewer defects such as pores and un-melted powder particles remained in their cross sections due to experiencing higher temperature during fabrication. The work is relevant to attempts to build high mechanical performance parts by selective laser sintering. [ABSTRACT FROM AUTHOR]

Bisphenol A epoxy resin (E51) and biscyanatophenylpropane (BCE) as polymer matrix and aluminum oxide (Al2O3, self-made by sol–gel method) as modification agent have been used to prepare two-phase Al2O3/E51–BCE composites for application in various fields. The curing process and kinetics of the system were determined by nonisothermal differential scanning calorimetry. The average apparent activation energy of the system calculated by the Kissinger and Ozawa methods was 67.8 kJ/mol. Scanning electron microscopy revealed that the interface between the Al2O3 phase and E51–BCE matrix phase was blurred and displayed mutual penetration. The fracture morphology of the Al2O3/E51–BCE composites exhibited ductile fracture. Al2O3 phase was uniformly dispersed in the matrix resin. The bending strength, bending modulus, and impact strength of the Al2O3/E51–BCE composites showed peak values of 172.3 MPa, 2.5 GPa, and 24.2 kJ/m2, being 24.4%, 19.1%, and 53.2% higher compared with the matrix resin, respectively, when the Al2O3 content was 3 wt.%. [ABSTRACT FROM AUTHOR]

The effect of Ca addition on the solidification microstructure of hypoeutectic Al-Si casting alloys was investigated using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) methods with particular attention focused on the change of morphologies of primary α-Al and eutectic silicon. Meanwhile, solute distribution in solid-liquid was simulated according to Scheil-Gulliver law. Results showed that primary α-Al and eutectic silicon were refined as Ca content increased because of the variation of the solute concentration in liquid. The addition of Ca increased the nucleation sites like Al3Ti or Al2Cu to promote the nucleation of primary α-Al. Affected by modification effect of Ca, the shape of eutectic silicon changed from flake to fibrous structure. In addition, coarse plate Ca-rich phases could be found along the grain boundary with high Ca content. [ABSTRACT FROM AUTHOR]

Phase relations in the Ga-Ge-Sb ternary system were investigated experimentally, using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and differential scanning calorimetry (DSC). Nine ternary samples were prepared by melting of pure elements under an argon atmosphere. The compositions of the prepared alloys were situated along three cross sections with the molar ratios Ga:Ge = 1, Ga:Sb = 1 and Ge:Sb = 1. Phase transition temperatures of the investigated samples were determined using DSC. The microstructure of the samples was analyzed using a scanning electron microscope with EDS and co-existing phases were identified. Binary thermodynamic data from literature, successfully used for phase diagram calculations of binary Ga-Ge, Ga-Sb and Ge-Sb systems, were used for the prediction of phase equilibria in the ternary Ga-Ge-Sb system. The activities of Ga in the liquid phase were calculated using the Redlich-Kister-Muggianu model and compared with experimental data reported in the literature. The liquidus projection, invariant equilibria and three vertical sections of the Ga-Ge-Sb ternary system were calculated and compared with the experimental results and a good agreement was observed. [ABSTRACT FROM AUTHOR]

A mixture of SiO2, C, and Mg powders is mechanically milled in a planetary ball mill during different milling times of 60, 90, 120, and 150 min. The milled powders are then used in a self-propagating high-temperature synthesis (SHS) reaction to produce the Si–SiC composite. The thermal properties of the milled powders are determined by using differential scanning calorimetry and thermogravimetry. The chemical composition and microstructure of both as-synthesized products and as-leached powders are characterized by the x-ray diffraction analysis and scanning electron microscopy, respectively. The results show that an increase in the milling times of the mixture of the reactant powders has a significant effect on the thermal properties, diffusion processes, and SHS reaction mechanisms, as well as on the phase conversion and the final yield of the products. [ABSTRACT FROM AUTHOR]

In order to investigate the role of thermo-oxidative aging on the crystal structure of crosslinked polyethylene (XLPE) at temperatures below and above the melting point, thermo-oxidative aging was conducted on XLPE cable insulation at 100, 120, 140 and 160 °C respectively. The crystal structure of the fresh sample and aged samples was characterized by X-ray diffraction, differential scanning calorimetry (DSC) and scanning electron microscopy tests. The concentration of antioxidants in XLPE samples was measured by the DSC method. It was deduced by the obtained results that the thermo-oxidative aging process could be divided into the physical aging stage and the chemical aging stage depending on the concentration of antioxidants in XLPE. In the physical aging stage, re-crystallization process led to the improvement of crystal structure and the increase in crystallinity. In the chemical aging stage, the breakage of intramolecular and intermolecular bonds led to drastic chains scission, resulting in the decrease in crystallinity. At 100 °C, the thermo-oxidative aging mainly affected the amorphous regions and had a limited effect on the crystalline regions. At 120, 140 and 160 °C, the thermo-oxidative aging affected the molten spherulites, resulting in decreased lamellae, increased lamellar spacing and the destruction of spherulites. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) and doxorubicine loaded-PU nanofiber mats were prepared by the electrospinning technique. The effect of some system and process parameters including flow rate, distance from collector, and concentration of solution on the size and morphology of nanofibers was investigated. The size, morphology and drug content of nanofiber mats were followed by scanning electron microscopy (SEM). FTIR and TGA methods were used for structural and thermal characterization, and DSC was also used for determining the form of drug within nanofiber mat. Doxorubicine release kinetics were studied in two different pHs (4.5 and 7.5) for two drug content and it was observed that there is an inverse correlation between the amounts of drug loaded and released. [ABSTRACT FROM AUTHOR]

Thermal characterization of geopolymer powder was investigated at room and elevated temperatures. The physical, chemical and mass change with respect to various temperatures have been studied. The physical properties such as density, porosity, and particle size were analyzed in geopolymer powder. The chemical and phase compositions were determined by x-ray fluorescence. The surface images of solid blocks of geopolymer were examined at room and elevated temperatures using scanning electron microscopy. Thermal expansion, shrinkage, and mass loss behavior towards the elevated temperatures were investigated by differential scanning calorimetry (DSC). The endothermic peak arising in the DSC curve is due to evaporation of water, chemical, gases and weight loss. [ABSTRACT FROM AUTHOR]

Development of (K,Na)NbO-based ceramics has attracted much attention in recent decades. In this work, KNaNbAlO ceramic was prepared using conventional solid-state processing. A deliquescence phenomenon was observed when the specimen was exposed to moist atmosphere. The reaction mechanism and cause of deliquescence were investigated using x-ray diffraction analysis, scanning electron microscopy, energy-dispersive spectrometry, electron microprobe analysis, inductively coupled plasma mass spectrometry, and thermogravimetric/differential scanning calorimetric analysis. The results revealed interactions mainly amongst the raw materials KCO, NaCO, and NbO as well as KCO, NaCO, and AlO, which can influence the sintering behavior of the mixture. (K,Na)NbO and (K,Na)AlO were present in the sintered KNaNbAlO ceramic, with the latter leading to deliquescence. During the sintering process, AlO reacts with alkali oxides (NaO and KO), which are the decomposition products of carbonates, to form (K,Na)AlO. In addition, AlO is more likely to react with KO compared with NaO. [ABSTRACT FROM AUTHOR]

Cycloaliphatic epoxy resin was modified by phenyl methyl silicone resin to investigate the influence of silicone content on the performance and reliability of epoxy packaged light-emitting diode. The silicone modification of epoxy encapsulants was characterized by transform infrared (FT-IR) spectrophotometer. Rotational rheometer was used to study rheology behavior. Differential scanning calorimetry, thermogravimetric analyses, dynamic mechanical analysis, thermomechanical analyzer were introduced to measure the thermal and mechanical properties. Ultraviolet visible spectrophotometer was utilized to study heat and ultraviolet resistance. In reliability test, scanning acoustic microscope and scanning electron microscope were applied to observe interfacial delamination. Water sorption process was monitored using gravimetric measurement. FT-IR study shows a chemical bonding between hydroxyl group of silicone resin and epoxy resin. With the incorporation of silicone resin, favorable properties were obtained such as higher thermal decomposition temperature, lower equilibrium water sorption, and better heat and UV resistance. Among these systems, 10% silicone modified epoxy resin exhibits the best performance in reliability test. [ABSTRACT FROM AUTHOR]

Twelve salts of 3-nitro-1,2,4-triazol-5-one (NTO) (ammonium, hydrazinium, guanidinium, aminoguanidinium, diaminoguanidinium, triaminoguanidinium, N-carbamoylguanidinium, semicarbazidium, 1,5-diamino-1,2,4-tetrazolium, 3,4,5- triamino-1,2,4-triazolium, 3,6,7-triamino-7H-[1, 2, 4]triazolo[5,1-c][1,2,4]triazol-2- ium, and 4,4′,5,5′-tetraamino-3,3′-bi-1,2,4-triazolium) were synthesized. The new salts were fully characterized by H and C NMR spectroscopy, infrared spectroscopy, and elemental analysis. The crystal structures of salts 10 and 11 were determined by single-crystal X-ray diffraction. All energetic salts except salt 6 exhibit excellent thermal stabilities with decomposition temperatures ranging from 203 to 270 °C. The densities of salts ranged from 1.65 to 1.88 g cm as measured by a gas pycnometer. Theoretical performance calculations (Gaussian 03 and EXPLO5 v6.01) yielded detonation pressures and detonation velocities for the energetic salts, ranging from 24.4 to 38.1 GPa and 8136 to 9575 m s, respectively. In particular, salt 2 has an outstanding detonation performance ( P = 38.1 GPa, v = 9575 m s) with a satisfactory acidity compared to that of NTO ( pK = 5.63 versus pK = 2.37). Furthermore, the particles of salt 2 form two-dimensional blades of submicron size, as determined by scanning electron microscopy analysis. Meanwhile, salt 2 was compatible with TNAZ, TATB, TKX-50, Al, NHClO, CL-20, TNT, and F2603 fluororubber, as determined by differential scanning calorimetry or vacuum stability tests. [ABSTRACT FROM AUTHOR]

By means of scanning electron microscopy, electron probe microanalyses, and differential scanning calorimetry, 21 alloys in both as-cast and annealed states were investigated to study the phase equilibria and phase transformations of the Al-Sc-Si system in the Al-rich corner. Based on the observed microstructure, the solidification paths of the as-cast alloys were analyzed. In addition, the phase equilibria of the Al-Sc-Si system at 500 °C were determined and phase transition temperatures for representative alloys are measured by means of DSC. For the sake of providing missing thermodynamic data, the enthalpies of formation at 0 K for the compounds ScSi, ScSi, and τ (AlScSi) were obtained by first-principles calculations. Based on the data from the present work and literature, the thermodynamic descriptions of the Sc-Si and Al-Sc-Si systems were developed. The Al-Sc-Si phase diagram in the entire composition range and the solidification characteristic in the Al-rich corner were then calculated. It is shown that the predicted solidification paths could describe the experimental observations reasonably. Based on the thermodynamic description obtained in this work, solution heat-treated and aged conditions of some Al-Sc-Si alloys are discussed, which suggests that the validated thermodynamic descriptions of this work could be helpful for the microstructure design of the Al-Sc-Si alloys. [ABSTRACT FROM AUTHOR]

This study investigated the synthesis of intermetallic compounds in the Ni-Al system based nanocomposite powders with AlO by mechanical alloying (MA) of NiO and Al powder mixture with various compositions. The structural changes of powder particles during mechanical alloying were studied by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermal analysis of as-milled powders was examined by differential scanning calorimetry (DSC). XRD results revealed that the intermetallic phase was first noticed for all compositions investigated in the current study after 1 h milling. The formation of intermetallic phase, however, was completed after 3 h milling for NiAl and NiAl phases and after 2 h for NiAl phase. The unreacted NiO present in as milled powder is reduced by Al at 590°C on heating. The TEM micrographs of 3 h milled NiAl-AlO, NiAl-AlO and NiAl-AlO powder particles reveal the nanocrystallinity of the powders. [ABSTRACT FROM AUTHOR]

Different proportions of polyamidoamine (PAMAM) dendrimer were blended with poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) resin in chloroform for film casting. Differential scanning calorimetry and scanning electron microscopy were employed to characterize the PHBV/PAMAM composite films upon stretching and tangential breaking. The results indicated that with the addition of PAMAM dendrimer, the glass transition temperature of the PHBV/PAMAM composite films became more distinct, indicating that the blends had a greater toughness than pure PHBV. The calculated crystallinity values indicated that the crystallinity of the PHBV/PAMAM blends was lower than that of PHBV (0.09-56.18 % vs. 73.18 %, respectively). Moreover, the mechanical performance tests indicated that the addition of PAMAM dendrimer considerably increased the tangential breaking strength of PHBV from 24.08 kN/m to as high as 62.03 kN/m, whereas the tensile strength remained basically unchanged. The optimal toughening effect was observed with a PAMAM dendrimer content of 3.0 phr. [ABSTRACT FROM AUTHOR]

In this work, the thermal stability of Cu-In alloys with 45.0 and 41.2 at.% In nominal compositions was investigated by differential scanning calorimetry (DSC), scanning electron microscopy, wavelength dispersive spectroscopy, and in-situ synchrotron x-ray powder diffraction (S-PXRD) over a temperature range from 25 up to 400 °C. The studied samples are mainly composed of a CuIn phase together with minor amounts of the B phase (based on the NiAs-NiIn type structure) and, in one of the samples, with a minor amount of pure In. No evidence of the CuIn (41.2 at.% In) phase was detected, not even in the sample with 41.2 at.% In nominal overall composition. The combined use of the S-PXRD and DSC techniques allowed us to identify two phase transitions involving the CuIn phase, one of them corresponding to the $$ \upeta^{\prime} \rightleftharpoons {\text{B}} + {\text{Cu}}_{11} {\text{In}}_{9} $$ reaction at T = 290 °C and the other to the peritectic $$ \upeta^{\prime} + {\text{L}} \rightleftharpoons {\text{Cu}}_{11} {\text{In}}_{9} $$ reaction at T = 311 °C. [ABSTRACT FROM AUTHOR]

The morphology evolution of thermoplastics made by micro-injection molding (μIM) in a uniform miniaturization manner has not been documented yet. In the present study, the crystal morphologies within μIM high-density polyethylene parts were investigated with the aid of rheology measurement, polarizing optical microscopy, scanning electron microscopy, and differential scanning calorimetry. It was discovered that unlike conventional injection molded parts with spherulites predominating, uniformly miniaturized products have highly oriented lamellae starting to appear in the skin layer. For 175-μm-thick μIM parts (M175), interlocking shish–kebab structures exist throughout the thickness. Furthermore, the origins of different crystal morphologies with various part thicknesses were discussed mainly from the viewpoints of rheology and thermodynamics. It was revealed that the flow-induced crystallization is one of the key factors responsible for the unique super structures. More quantitatively, there is a critical shear rate of 3.0 × 10 5 s −1 existing for forming highly oriented molecular structures. Meanwhile, on the basis of the model from the literature, an elongational rate as high as 4.4 × 10 4 s −1 was also identified at the channel center for M175. [ABSTRACT FROM AUTHOR]

Second phases in the AZ31 as-cast magnesium alloys with different Sr contents (0, 0.1, 0.5, 1.0, 2.0, and 5.0 wt%) were investigated using scanning electron microscopy, energy dispersive spectrometry, differential scanning calorimetry, X-ray diffraction, and transmission electron microscopy. The results indicated that the Mg21(Zn, Al)17 phase with small amount was formed in the AZ31 as-cast alloy without Sr addition, in addition to the Mg17Al12 phase. At the same time, the alloy with the addition of 0.1 wt% Sr mainly consisted of the α-Mg, Mg17Al12, Mg21(Zn, Al)17, and Al4Sr phases. In addition, the α-Mg, Mg21(Zn, Al)17 and Al4Sr phases were found to be the main second phases for the alloy with the addition of 0.5 wt% Sr. However, only the α-Mg, Al4Sr and (Mg, Al)17Sr2 phases were mainly formed in the AZ31 alloy with the addition of 1.0 wt% Sr. As for the alloys with the additions of 2 and 5 wt% Sr, their as-cast microstructures were mainly composed of the α-Mg and (Mg, Al)17Sr2 phases. [ABSTRACT FROM AUTHOR]

The microstructures, phase transformations, and wettability of Sn-Bi-Zn solder alloys were investigated by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry (DSC). The results show that the alloys are composed of primary Sn-rich phase or Zn-rich phase, (Sn + Zn) eutectic structure, and (Sn + Bi + Zn) ternary eutectic structure. The microstructural characterization of Sn- xBi-Zn alloys indicates that, with increasing Bi content, more of the eutectic (Sn-Bi-Zn) structures is formed. DSC profiles reveal that the eutectic peak of the samples did not differ very much, but the reaction temperature of the alloys decreases with increased Bi content. The spreading rates of solders increased with the addition of Zn, which affects the interfacial reactions between the solders and copper. [ABSTRACT FROM AUTHOR]