Thermogravimetric, Morphological and Infrared Analysis of Blends Involving Thermoplastic Starch and Poly(ethylene-co-methacrylic acid) and Its Ionomer Form

This study focuses on the thermal properties and structural features of blends consisting of thermoplastic starch (TPS) and poly(ethylene-co-methacrylic acid) copolymer (EMAA) or its ionomer form (EMAA-54Na). The aim is to investigate how carboxylate functional groups of the ionomer form intervene in blends compatibility at the interface of the two materials and how this impacts their properties. Two series of blends (TPS/EMAA and TPS/EMAA-54Na) were produced with an internal mixer, with TPS compositions between 5 and 90 wt%. Thermogravimetry shows two main weight losses, indicating that TPS and the two copolymers are primarily immiscible. However, a small weight loss existing at intermediate degradation temperature between those of the two pristine components reveals specific interactions at the interface. At a mesoscale level, scanning electron microscopy confirmed thermogravimetry results and showed a two-phase domain morphology, with a phase inversion at around 80 wt% TPS, but also revealed a different surface appearance evolution between the two series. Fourier-transformed infrared spectroscopy analysis also revealed discrepancies in fingerprint between the two series of blends, analysed in terms of additional interactions in TPS/EMAA-54Na coming from the supplementary sodium neutralized carboxylate functions of the ionomer.

Three-Dimensional Printed Subsurface Defect Detection by Active Thermography Data-Processing Algorithm

This article evaluates an active thermography algorithm to detect subsurface defects in materials made by additive manufacturing (AM). It is based on the techniques of thermographic signal reconstruction (TSR), thermal contrast, and the physical principles of heat transfer. The subsurface defects have different infill, depth, and size. The results obtained from this algorithm are compared with state-of-the-art TSR technique and show the high performance of the proposed algorithm even for subsurface defects done by 3D AM. The resulting images are better shown using the absolute difference in the place of variance. The proposed algorithm has higher contrast, better sensitivity to the defect depths, and lower noise than the TSR. The resultant image is quite clean and gives no doubt where the subsurface defects are.

Thermal Analysis of a Reactive Variable Viscosity TiO2-PAO Nanolubricant in a Microchannel Poiseuille Flow

This paper examines the flow structure and heat transfer characteristics of a reactive variable viscosity polyalphaolefin (PAO)-based nanolubricant containing titanium dioxide (TiO₂) nanoparticles in a microchannel. The nonlinear model equations are obtained and numerically solved via the shooting method with Runge-Kutta-Fehlberg integration scheme. Pertinent results depicting the effects of emerging thermophysical parameters on the reactive lubricant velocity, temperature, skin friction, Nusselt number and thermal stability criteria are presented graphically and discussed. It is found that the Nusselt number and thermal stability of the flow process improve with exothermic chemical kinetics, Biot number, and nanoparticles volume fraction but lessen with a rise in viscous dissipation and activation energy.

Porous 8YSZ Ceramics Prepared with Alkali Halide Sacrificial Additives

8 mol% Y₂O₃-stabilized ZrO₂ (8YSZ) ceramics were prepared with KCl and LiF additions to obtain porous specimens with high skeletal density. Thermogravimetric and differential thermal analyses (TG/DTA) were carried out on 8YSZ and on 8YSZ mixed to 5 wt.% KCl or 5 wt.% LiF as sacrificial pore formers that were thermally removed during sintering. The melting and evaporation of the alkali halides were evaluated by differential thermal analysis. Dilatometric analysis was also carried out following the same TG/DTA temperature profile with results suggesting rearrangement of the 8YSZ particles during LiF and KCl melting. The dilatometric data of 8YSZ green pellets mixed to KCl or LiF exhibited an initial expansion up to the melting of the alkali halide, followed by shrinkage due to sintering evolution with grain growth and pore elimination. The time that the alkali halide molten phase was kept during sintering was found to be an important parameter for obtaining 8YSZ-sintered specimens with specific pore content; bulk density and open porosity could then be tuned by controlling the time the alkali halide remained liquid during sintering. Scanning electron microscopy images of the pellet fracture surfaces showed pores that contributed to increasing the electrical resistivity as evaluated by impedance spectroscopy analysis.

Statistical Copolymers of N-Vinylpyrrolidone and 2-Chloroethyl Vinyl Ether via Radical RAFT Polymerization: Monomer Reactivity Ratios, Thermal Properties, and Kinetics of Thermal Decomposition of the Statistical Copolymers

The radical statistical copolymerization of N-vinyl pyrrolidone (NVP) and 2-chloroethyl vinyl ether (CEVE) was conducted using the Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization technique, employing [(O-ethylxanthyl)methyl]benzene (CTA-1) and O-ethyl S-(phthalimidylmethyl) xanthate (CTA-2) as the Chain Transfer Agents (CTAs), leading to P(NVP-stat-CEVE) products. After optimizing copolymerization conditions, monomer reactivity ratios were estimated using various linear graphical methods, as well as the COPOINT program, which was applied in the framework of the terminal model. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the monomers' mean sequence lengths. Thermal properties of the copolymers were studied by Differential Scanning Calorimetry (DSC) and kinetics of their thermal degradation by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG), applying the isoconversional methodologies of Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS).

An Investigative Study on the Structural, Thermal and Mechanical Properties of Clay-Based PVC Polymer Composite Films

The present study aims to explore the impact of pristine and surfactant-modified clays (montmorillonite, bentonite and vermiculite) on the thermomechanical properties of a poly (vinyl chloride) (PVC) polymer film. Initially, clay was modified by employing the ion exchange method. The modification of clay minerals was confirmed by the XRD pattern and thermogravimetric analysis. Pristine PVC polymer film and clay (montmorillonite, bentonite and vermiculite)-based PVC polymer composite films were fabricated using solution casting. The ideal dispersion of surfactant-modified organo-clays was observed in the PVC polymer matrix due to the hydrophobic nature of modified clays. The resultant pure polymer film and clay polymer composite film were characterized using XRD and TGA, and their mechanical properties were determined using a tensile strength tester and Durometer. From the XRD pattern, the intercalation of the PVC polymer film was found in the interlayer of organo-clay while exfoliation or partial intercalation and exfoliation were observed for pristine clay mineral-based PVC polymer composite films. Thermal analysis indicated a lowering of the decomposition temperature of the composite film as clay promotes the thermal degradation temperature of PVC. Improvement in the tensile strength and hardness was found to be more frequent in the case of organo-clay-based PVC polymer films, which is only due to the hydrophobic nature of organ clays, resulting in greater compatibility with the polymer matrix.

Preparation of Mesoporous Si Nanoparticles by Magnesiothermic Reduction for the Enhanced Reactivity

In this study, mesoporous silicon nanoparticles (M-Si) were successfully prepared by a magnesiothermic reduction of mesoporous silica nanoparticles, which were synthesized by a templated sol-gel method and used as the precursors. M-Si exhibited a uniform size distribution with an average diameter of about 160 nm. The measured BET surface area was 93.0 m² g^-1, and the average pore size calculated by the BJH method was 16 nm. The large internal surface area provides rich reaction sites, resulting in unique interfacial properties and reduced mass diffusion limitations. The mechanism of the magnesiothermic reduction process was discussed. The reactivity of prepared M-Si was compared with that of commercially available non-porous Si nanopowder (with the average diameter of about 30 nm) by performing simultaneous thermogravimetry and differential scanning calorimetry in the air. The results showed that the reaction onset temperature indicated by weight gain was advanced from 772 °C to 468 °C, indicating the promising potential of M-Si as fuel for metastable intermolecular composites.

Mechanical Reclamation of Spent Moulding Sand on Chromite Sand Matrix; Removal of Alkali-Phenolic Binder

The foundry industry generates large amounts of waste when casting metal into sand moulds. An important issue is the activities that are related to the re-recovery of the grain matrix (the main component of the moulding sand) for realising subsequent technological cycles. This process is particularly important in the case of the expensive chromite matrix that is necessary for use in manganese steel casting. The effects of the reclamation treatments of spent alkali-phenolic binder sand were evaluated by scanning electron microscopy with EDS, analysing the chemical composition in micro areas and proving the loss of binder on the surfaces of the matrix grains. Tests were also performed using the main criteria for evaluating a reclaimed organic binder: sieve analysis and ignition loss. A thermogravimetric analysis study was performed to assess the change in the chromite character of the grain matrix under the influence of temperature. The effects of the reclamation measures were verified by making moulding compounds on a matrix of reclaimed sand and a mixture of reclaimed and fresh sand. The tests and analyses that were carried out indicated the direction of an effective method for reclaiming used alkali-phenolic binder masses and the extent of the proportion of the regenerate in moulding sand in order to maintain the relevant technological parameters of the moulding sand.

Effect of Excipients on the Quality of Drug Formulation and Immediate Release of Generic Metformin HCl Tablets

Generic medications are bioequivalent to brand-name medications, but the quality and purity of generic medications are still debatable. The aim of this study was to compare the generic product of metformin (MET) to its branded counterpart using pure MET powder as a reference. Quality control tablet assessment and in vitro evaluation of drug release were carried out in various pH media. Additionally, several analytical methods and thermal techniques were used, namely differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and confocal Raman microscopy. The results showed a significant difference between the two products. In terms of friability assessment, mean resistance force, and tablet disintegration, the generic MET product showed significant weight loss, higher mean resistance force, longer disintegration time, and a slower rate of drug release. In addition, DSC and TGA showed that the generic product had the lowest melting point and the least weight loss compared to the branded product and pure powder. XRD and SEM demonstrated some changes in the crystallinity structure of the molecule particles for the generic product. Additionally, FTIR and confocal Raman revealed the same peaks and band shifts in all samples, but with differences in the intensity for the generic tablet only. The observed differences could be due to the use of different excipients in the generic product. The possibility of forming a eutectic mixture between the polymeric excipient and metformin in the generic tablet was presumed, which might be attributed to alterations in the physicochemical properties of the drug molecule in the generic product. In conclusion, using different excipients might have a significant effect on the physicochemical properties of drugs in generic formulations, leading to significant changes in drug release behavior.

Investigation of reactions occurring in waste combustion ash using thermal analysis coupled with gas analysis and characterization

Waste-to-energy (WtE) ash was investigated for thermal reactions that generate gas components such as hydrogen and carbon dioxide. An evolved gas detection method coupled with thermal gravimetric analysis and differential scanning calorimetry provided insight into the possible reactions occurring in WtE ash at temperatures ranging from 90°C to 600°C in an inert environment. The combined analysis shows that H₂ is produced from WtE ash at temperatures ~298°C and is detected until ~480°C. CO₂ appears in the evolved gas starting at 290°C and continues to increase as the temperature is increased. The results reveal that the processes releasing H₂ and the CO₂ are independent of each other, and the CO₂ generation depends on the constant input of energy. These results enable the identification of the possible processes occurring in WtE ash decomposition of Friedel's salt at 280°C and dehydration of Ca(OH)₂ at 410°C, both of which release H₂O that reacts with the aluminium present to release H₂. At temperatures higher than 480°C, an alumina layer is formed preventing further production of H₂. X-ray diffraction analysis done on the WtE ash verifies the presence of chemical phases that support the proposed reactions. The outcome of this study enables identifying the possible reactions in WtE ash that can be causing the energy changes seen during disposal, storage and transportation of ash. These results can give direction for detailed understanding and development of the kinetics and the mechanisms of the reactions occurring in WtE ash which is important for optimization of reuse and disposal of ash.

Crystal structure and characterization of the sulfamethazine-piperidine salt

Sulfamethazine [N¹-(4,6-dimethylpyrimidin-2-yl)sulfanilamide] is an antimicrobial drug that possesses functional groups capable of acting as hydrogen-bond donors and acceptors, which make it a suitable supramolecular building block for the formation of cocrystals and salts. We report here the crystal structure and solid-state characterization of the 1:1 salt piperidinium sulfamethazinate (PPD⁺·SUL^-, C₅H₁₂N⁺·C₁₂H₁₃N₄O₂S^-) (I). The salt was obtained by the solvent-assisted grinding method and was characterized by IR spectroscopy, powder X-ray diffraction, solid-state ¹³C NMR spectroscopy and thermal analysis [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)]. Salt I crystallized in the monoclinic space group P2₁/n and showed a 1:1 stoichiometry revealing proton transfer from SUL to PPD to form salt I. The PPD⁺ and SUL^- ions are connected by N-H⁺...O and N-H⁺...N interactions. The self-assembly of SUL^- anions displays the amine-sulfa C(8) motif. The supramolecular architecture of salt I revealed the formation of interconnected supramolecular sheets.

Induced Piezoelectricity in Cotton-Based Composites for Energy-Harvesting Applications

A flexible and easily processable polymer composite is developed from naturally occurring piezoelectric materials for efficient energy-harvesting applications. Tomato peel (TP)- and cotton (CTN)-based poly(vinylidene fluoride) (PVDF) composites have been prepared and the role of induced electroactive phases have been explored through structural, thermal, and morphological analyses for their applications in energy production. The mechanism of induced piezoelectricity is vividly demonstrated using electromechanical responses and characteristic changes due to induction phenomena. The CTN-based composite generates a maximum output voltage and current of 65 V and 2.1 μA, respectively, as compared to the maximum output voltage and current of 23 V and 0.7 μA in TP-based composites due to the significant induction of the piezoelectric phase in the presence of suitable electroactive cotton. The fabricated device is able to store charges in capacitors and converts the external stress through different motions of the human body to generate a considerable output, which describes the applicability of the material and justifies the potential as an efficient and sustainable biomechanical energy harvester.

Thermal Analysis of Flip-Chip Bonding Designs for GaN Power HEMTs with an On-Chip Heat-Spreading Layer

In this work, we demonstrated the thermal analysis of different flip-chip bonding designs for high power GaN HEMT developed for power electronics applications, such as power converters or photonic driver applications, with large gate periphery and chip size, as well as an Au metal heat-spreading layer deposited on top of a planarized dielectric/passivation layer above the active region. The Au bump patterns can be designed with high flexibility to provide more efficient heat dissipation from the large GaN HEMT chips to an AlN package substrate heat sink with no constraint in the alignment between the HEMT cells and the thermal conduction bumps. Steady-state thermal simulations were conducted to study the channel temperatures of GaN HEMTs with various Au bump patterns at different levels of current and voltage loadings, and the results were compared with the conventional face-up GaN die bonding on an AlN package substrate. The simulations were started from a single finger isolated HEMT cell and then extended to multiple fingers HEMT cells (total gate width > 40 mm) to investigate the "thermal cross-talk" effect from neighboring devices. Thermal analysis of the GaN HEMT under pulse operation was also performed to better reflect the actual conditions in power conversion or pulsed laser driver applications. Our analysis provides a combinational assessment of power GaN HEMT dies under a working condition (e.g., 1MHz, 25% duty cycle) with different flip chip packaging schemes. The analysis indicated that the channel temperature rise (∆T) of a HEMT cell in operation can be reduced by 44~46% by changing from face-up die bonding to a flip-chip bonding scheme with an optimized bump pattern design.

Preparation and Surface Characterization of Cerium Dioxide for Separation of 68Ge/68Ga and Other Medicinal Radionuclides

The overall need for the preparation of new medicinal radionuclides has led to the fast development of new sorption materials, extraction agents, and separation methods. Inorganic ion exchangers, mainly hydrous oxides, are the most widely used materials for the separation of medicinal radionuclides. One of the materials that has been studied for a long time is cerium dioxide, a competitive sorption material for the broadly used titanium dioxide. In this study, cerium dioxide was prepared through calcination of ceric nitrate and fully characterized using X-ray powder diffraction (XRPD), infrared spectrometry (FT-IR), scanning and transmission electron microscopy (SEM and TEM), thermogravimetric and differential thermal analysis (TG and DTA), dynamic light scattering (DLS), and analysis of surface area. In order to estimate the sorption mechanism and capacity of the prepared material, characterization of surface functional groups was carried out using acid-base titration and mathematical modeling. Subsequently, the sorption capacity of the prepared material for germanium was measured. It can be stated that the prepared material is prone to exchange anionic species in a wider range of pH than titanium dioxide. This characteristic makes the material superior as a matrix in ⁶⁸Ge/⁶⁸Ga radionuclide generators, and its suitability should be further studied in batch, kinetic, and column experiments.

The Chemistry, Recrystallization and Thermal Expansion of Brannerite from Akchatau, Kazakhstan

Numerous studies expose the potential of brannerite to become a good matrix, concentrating fission products and actinides. Minerals can complement the data collected from the synthetic materials and offer an advantage of a long-time exposure to radiation. Natural metamict brannerite from Akchatau, Kazakhstan, and its annealed sample were studied by EPMA, Raman spectroscopy, TGA, DSC, XRD and HTXRD. The radioactivity of pristine and annealed samples of brannerite was measured. Brannerite from Akchatau is characterized by the absence of significant amounts of REE and yttrium. The studied brannerite regains its structure at a temperature ~650 °C, revealed by the HTXRD and DSC. HTXRD was also performed on the annealed recrystallized brannerite. The thermal expansion for brannerite has been determined for the first time. The brannerite structure expands anisotropically with temperature increase. All the thermal expansion coefficients are positive except for α_β. The decreasing beta parameter indicates a "shear structural deformation". The angle between the 1st axis of the tensor and the crystallographic a axis decreases with the increase of the temperature. The structure expands mostly in the α₁₁ direction, approaching the bisector of the β angle. Brannerite has a low CTE at room temperature-α_v = 16 × 10^-6 °C^-1, which increases up to 39.4 × 10^-6 °C^-1 at 1100 °C. In general, the thermal stability of brannerite is comparable to that of the other perspective oxide radioactive waste-immobilizing matrices (e.g., Ln₂Zr₂O₇, CePO₄, CaTiO₃, CaZrTi₂O₇). The calculated thermal expansion of brannerite and the understanding of its underlying crystal chemical mechanisms may contribute to the behavior prediction of the material (both metamict and crystalline) at high temperatures.

Emulsion-Based Coatings for Preservation of Meat and Related Products

One of the biggest challenges faced by the meat industry is maintaining the freshness of meat while extending its shelf life. Advanced packaging systems and food preservation techniques are highly beneficial in this regard. However, the energy crisis and environmental pollution demand an economically feasible and environmentally sustainable preservation method. Emulsion coatings (ECs) are highly trending in the food packaging industry. Efficiently developed coatings can preserve food, increase nutritional composition, and control antioxidants' release simultaneously. However, their construction has many challenges, especially for meat. Therefore, the following review focuses on the essential aspects of developing ECs for meat. The study begins by classifying emulsions based on composition and particle size, followed by a discussion on the physical properties, such as ingredient separation, rheology, and thermal characteristics. Furthermore, it discusses the lipid and protein oxidation and antimicrobial characteristics of ECs, which are necessary for other aspects to be relevant. Lastly, the review presents the limitations of the literature while discussing the future trends. ECs fabricated with antimicrobial/antioxidant properties present promising results in increasing the shelf life of meat while preserving its sensory aspects. In general, ECs are highly sustainable and effective packaging systems for meat industries.

Influence of Methacrylate and Vinyl Monomers on Radical Bulk Photopolymerization Process and Properties of Epoxy-Acrylate Structural Adhesives

In this paper, epoxy-acrylate structural adhesives tapes (SATs) were obtained from Bisphenol A-based liquid epoxy resin and epoxy acrylic resins (EARs). A new method of EARs preparation, i.e., the free radical bulk photopolymerization process (FRBP), was studied in detail. The influence of methacrylic monomers (methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate, (2-acetoacetoxy)ethyl methacrylate) and vinyl monomers (N-vinylpyrrolidone and styrene) on the FRBP process of base monomers (i.e., butyl acrylate, glycidyl methacrylate and 2-hydroxyethyl acrylate) was investigated. The kinetics of photopolymerization process was monitored by photo-differential scanning calorimetry method. The properties of the obtained EARs (viscosity and average molecular weights), as well as monomers conversion using ¹H NMR, were determined. It was revealed that styrene significantly decreases the photopolymerization rate and increases the final monomers conversion (+27%). However, the resulting tetrapolymers BA-co-GMA-co-HEA-co-STY have low molecular weights and low polydispersity (2.2). Methacrylate monomers with shorter aliphatic chains (<C₄) also decrease the rate of photopolymerization due to the length of the aliphatic chain increasing. Surprisingly, the best results of adhesion to steel and shear strength were obtained for SAT based on epoxy acrylate resin with styrene (11 N/25 mm and 20.8 MPa, respectively). However, the thermomechanical properties of SAT with styrene were weaker than those with methacrylates.

The Impact of Ions Contained in Concrete Pore Solutions on Natural Zeolites

This article investigates the relationships between different chemical compositions of simulated cement concrete pore solutions and changes on the surface of zeolite rock with potassium clinoptilolite as its main component. The changes were studied using X-ray diffraction (XRD), thermal analysis (DTA-TG) and scanning electron microscopy (SEM). Zeolite powder samples and a ground section of 16-64 mm grain were tested. The simulated pore solutions were based on Ca, Na, K hydroxides and K₂SO₄. It was found that 100% of Ca(OH)₂ in the systems could react between 7 and 180 days of hydration due to pozzolanic and side reactions. As the degree of clinoptilolite conversion increased, it became more difficult to detect it in X-ray patterns. At the same time, various microstructural changes could be observed. As a result of the reactions that occurred, hydrated calcium silicates, sulfate and carbonate compounds were formed. Potassium hydroxide had a more substantial effect on clinoptilolite reactivity than sodium hydroxide. This effect can be enhanced by the presence of SO₂^3- ions in the solution.

The Effect of Cooling Layer Thickness and Coolant Velocity on Crystal Thermodynamic Properties in a Laser Amplifier

Laser diode pumped solid-state lasers (DPSSLs) have been widely used in many fields, and their thermal effects have attracted more and more attention. The laser diode (LD) side-pumped amplifier, as a key component of DPSSLs, is necessary for effective heat dissipation. In this paper, instead of the common thermal analysis based only on a crystal rod model, a fluid-structure interaction model including a glass tube, cooling channel, coolant and crystal rod is established in numerical simulation using ANSYS FLUENT for the configuration of an LD array side-pumped laser amplifier. The relationships between cooling layer thickness, coolant velocity and maximum temperature, maximum equivalent stress, inlet pressure and the convective heat transfer coefficient are analyzed. The results show that the maximum temperature (or maximum equivalent stress) decreases with the increase in the coolant velocity; at low velocity, a larger cooling layer thickness with more coolant is not conductive enough for improved heat dissipation of the crystal rod; at high velocity, when the cooling layer thickness is above or below 1.5 mm, the influence of the cooling layer thickness on the maximum temperature can be ignored; and the effect of the cooling layer thickness on the maximum equivalent stress at high velocity is not very significant. The comprehensive influence of various factors should be fully considered in the design process, and this study provides an important reference for the design and optimization of a laser amplifier and DPSSL system.

Influence of Short-Pulse Microwave Radiation on Thermochemical Properties Aluminum Micropowder

The thermochemical properties of Al micropowder after exposure to microwave irradiation were investigated. The Al micropowder was exposed to microwave irradiation in air with a frequency of 2.85 GHz, a power density of 8 W/cm², and a pulse duration of 25 ns and 3 µs. The thermochemical parameters of the irradiated metal powders were determined by the method of thermal analysis at the heating in air. It was found that an increase in the duration of microwave pulses and irradiation time leads to the thermal annealing of the metal particles, and the thermal processes of melting and sintering begin to dominate over non-thermal processes. The specific thermal effect of irradiated Al micropowder oxidation increases from 7744 J/g to 10,154 J/g in comparison with the unirradiated powder. The modeling of thermal heating processes of aluminum (Al) micropowder under the action of pulsed microwave radiation has been performed. It is shown that with an increase in the duration of microwave pulses and irradiation time, a significant heating of the Al micropowder occurs, leading to its melting and sintering. The results of modeling on the action of microwave radiation on the Al micropowder were compared with experimental results.

Mechanical and Thermal Properties of Wood-Fiber-Based All-Cellulose Composites and Cellulose-Polypropylene Biocomposites

This article explores wood-fiber-based fabrics containing Lyocell yarn in the warp and Spinnova-Lyocell (60%/40%) yarn in the weft, which are used to form unidirectional all-cellulose composites (ACC) through partial dilution in a NaOH-urea solution. The aim is to investigate the role of the yarn orientation in composites, which was conducted by measuring the tensile properties in both the 0° and 90° directions. As a reference, thermoplastic biocomposites were prepared from the same fabrics, with biobased polypropylene (PP) as the matrix. We also compared the mechanical and thermal properties of the ACC and PP biocomposites. The following experiments were carried out: tensile test, TGA, DSC, DMA, water absorption test and SEM. The study found no significant difference in tensile strength regarding the Spinnova-Lyocell orientation between ACC and PP biocomposites, while the composite tensile strength was clearly higher in the warp (Lyocell) direction for both composite variants. Elongation at break doubled in ACC in the Lyocell direction compared with the other samples. Thermal analysis showed that mass reduction started at a lower temperature for ACC, but the thermal stability was higher compared with the PP biocomposites. Maximum thermal degradation temperature was measured as being 352 °C for ACC and 466 °C for neat PP, and the PP biocomposites had two peaks in the same temperature range (340-474 °C) as ACC and neat PP combined. ACCs absorbed 93% of their own dry weight in water in just one hour, whereas the PP biocomposites BC2 and BC4 absorbed only 10% and 6%, respectively. The study highlights the different properties of ACC and PP reference biocomposites that could lead to further development and research of commercial applications for ACC.

Thermal Analysis of Terfenol-D Rods with Different Structures

To reduce the heating of the Terfenol-D rod and evaluate its working efficiency, six kinds of Terfenol-D rods were designed, and the temperature field of the rods was simulated and calculated using the finite element method to obtain the temperature distribution. The results showed that the untreated rod had the highest temperature; the temperature was higher in the middle and lower at both ends; higher on the outer diameter surface; and lower on the inside. When compared to the untreated rod, the temperatures of sliced rods and slit rods decreased, and the temperature of sliced rods was lower than that of slit rods; the temperature of slit rods was higher in the middle and lower at both ends; the temperature distribution of sliced rods was more uniform relatively; the slice treatment rod had the lowest temperature and the best heat suppression effect. Three structural rods were chosen and manufactured from a total of six that were tested. It shows that the temperature of all rods was higher in the middle and lower at both ends after 30 min of operation. The actual temperature of untreated rod was 34 °C, the actual temperature of radially slit rod was 32 °C, and the actual temperature of sliced rod at both ends was 28 °C. The tested temperature distributions of three rods agreed with the calculated ones.

Thermoanalytical and X-ray Diffraction Studies on the Phase Transition of the Calcium-Substituted La2Mo2O9 System

An aqueous sol-gel preparation technique was applied for the synthesis of calcium-substituted lanthanum molybdate with the initial composition of La_2-xCa_xMo₂O_9-x/2. The influence of the substitution effect, which plays a crucial role in the formation of final ceramics, was investigated. The thermal behavior tendencies of phase transition at elevated temperatures from the monoclinic crystal phase to cubic as well as reversible transformation were identified and discussed in detail. It was proved that the phase transformation in the obtained mixture significantly depends only on the impurities' amount, while the partial substitution by calcium atoms above the value of x = 0.05 does not create a homogeneous multicomponent system for La_2-xCa_xMo₂O_9-x/2 composition.

Investigations on Five PMMA Closed Types of Piezo Actuators as a Cooling Fan

There are five closed types of piezo actuators (closed type of PA, closed PA) as a cooling fan relative to those different PAJs of the previous work (open type of PAJ, open PAJ) for analysis in the present study. Closed PA was composed of circular piezoelectric ceramics (PCs) and acrylic (PMMA) plates and investigated on five different types at operating conditions. The results show that the noise of the closed PA is quieter than that of the open PAJ by about 10 dB. When the closed PA is deposed at a suitable distance of 10 to 20 mm from the heat source, averting sucking back the high-temperature fluids around that, the thermal convection coefficient is above 120% more than that of the conventional rotary fan. The cooling performances of these five closed PAs were evaluated by thermal analysis technique, and the convection thermal resistance of the best closed PA can be decreased by over 15%. In terms of energy consumption, a monolithic closed PA was less than 10% than that of a rotary fan. Among these five closed PAs, the best one has the essential qualities that the diameter of the piezoelectric sheet is 41 mm, the opening length is 4 mm, and the outer opening length is 10 mm. Moreover, the best operating conditions are a voltage frequency of 300 Hz and a release distance of 15 mm in the present study.

Synthesis, Crystal Structure, and Characterization of Energetic Salts Based on 3,5-Diamino-4H-Pyrazol-4-One Oxime

In order to broaden the study of energetic cations, a cation 3,5-diamino-4H-pyrazol-4-one oxime (DAPO) with good thermal stability was proposed, and its three salts were synthesized by a simple and efficient method. The structures of the three salts were verified by infrared spectroscopy, mass spectrometry, elemental analysis, and single crystal X-ray diffraction. The thermal stabilities of the three salts were verified by differential scanning calorimetry and thermos-gravimetric analysis. DAPO-based energetic salts are analysed using a variety of theoretical techniques, such as 2D fingerprint, Hirshfeld surface, and non-covalent interaction. Among them, the energy properties of perchlorate (DAPOP) and picrate (DAPOT) were determined by EXPLO5 program combined with the measured density and enthalpy of formation. These compounds have high density, acceptable detonation performance, good thermal stability, and satisfactory sensitivity. The intermolecular interactions of the four compounds were studied by Hirshfeld surface and non-covalent interactions, indicating that hydrogen bonds and π-π stacking interactions are the reasons for the extracellular properties of perchlorate (DAPOP) and picrate (DAPOT), indicating that DAPO is an optional nitrogen-rich cation for the design and synthesis of novel energetic materials with excellent properties.