Preparation of microencapsulated PCMs for energy saving and thermal comfort of buildings

Energy improvement techniques for buildings are among the modern studies that concentrate on new techniques and methods of saving energy and improving the thermal performance in buildings. This research aims to prepare microencapsulated-PCMs (micro-PCMs) by using local materials and studied the influence of using micro-PCMs on thermal performance improvement and PCMs leakage problems improvement. The micro-PCMs of paraffin wax were prepared as the core PCMs materials while the melamine-formaldehyde polymer as the shell. The micro-PCMs were characterized through scanning electron-microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. Analysis results showed the prepared micro-PCMs present a regular spherical shape and confirm that the formation composite of the shell effectively encapsulated the cores. Furthermore, the absence of chemical interaction between the MF and the PW components. The micro-PCM have potential for architectural applications in the building-envelope to store thermal energy, provide indoor-temperature at the comfortable range, and reduce the consumption energy in buildings.

Ultrasound Imaging and Antithrombotic Effects of PLA-Combined Fe3O4-GO-ASA Multifunctional Nanobubbles

PLA-combined ferroferric oxide–graphene oxide–aspirin (Fe3O4-GO-ASA) multifunctional nanobubbles were prepared using the double emulsion-solvent evaporation method. The obtained composite nanobubbles had a regular spherical shape, Zeta potential of (−36.5 ± 10.0) mV, and particle size distribution range of 200–700 nm. The experimental results showed that PLA-combined Fe3O4-GO-ASA nanobubbles could effectively improve the antithrombin parameters of PT, TT, APTT, and INR, and significantly inhibit thrombosis when the composite nanobubbles with a concentration of 80 mg·mL−1 interacted with the rabbit blood. The prepared composite nanobubbles could reach a significant ultrasonic imaging effect and good magnetic targeting under the magnetic field when the nanobubbles' concentration was only 60 mg·mL−1.

Synthesis and Spectrophotometric Analysis of Microcapsules Containing Immortelle Essential Oil

In this study, microcapsules were prepared by solvent evaporation technique using ethyl cellulose component as wall and essential oil as core material. The synthesis of microcapsules was carried out using different oil masses. The analysis of the microcapsules was carried out using field emission scanning electron microscope (FE-SEM) and UV spectrophotometric analysis using absorption spectrophotometer. The obtained results confirm the regular spherical shape and size of the synthesized microcapsules. The qualitative and quantitative spectrophotometric analysis of the microencapsulated immortelle oil was measured at the wavelength of 265 nm. The calibration diagram was used to calculate the unknown concentrations of the microencapsulated oil. The obtained results confirm the application of the presented method as relevant for the possible determination of microencapsulated oil on textile materials.

Investigation of the Microstructure of a Sintered Sample Obtained from Powder Steel X13

This article presents the results of a study of the microstructure of a sintered sample made of alloy X13 electroerosive materials obtained in butyl alcohol. It has been established that during the sintering of electroerosive materials made of alloy X13 by the method of spark plasma sintering, the main elements on the surface of the particles are Fe, Cr, Mn, and the particles have a generally regular spherical shape.

Experimental study of fractional composition of pieces of brittle material during crushing in a single-roll crusher with block stop on the roll

Processing of bulk materials used in metallurgical industry to obtain necessary grades of size requires application of crushing machines, including a single-roll type. Indicators of crushing process are degree and efficiency of crushing. Degree of crushing is estimated by the ratio of size of initial crushed and resulting pieces, which depends on size of the gap between a roll and a fixed jaw. The Siberian State Industrial University has patented, designed and manufactured a pilot unit, which is a single-roll crusher with block stop on the roll to study crushing process. A series of experiments on different samples (in shape, size and strength) crushing was carried out on the developed unit. Technique of the experiment and the design of a single-roll crusher with block stop on the roll were described. Results of destruction of the samples of isotropic material made of sand-cement mixture of regular (spherical) shape are presented. Samples from isotropic material allow comparison of analytical conclusions of determining position of the plane of action of maximum tangential stresses with experimental data. Samples of anisotropic material (for example, ferroalloy) were also destroyed. It was experimentally determined that the larger is clearance between the roll and the fixed jaw, the larger is the size of fraction of finished product and over-grinding is less than after crushing the same piece with a smaller clearance. The degree of crushing in a single-roll crusher with block stop on the roll cannot be equal to 4 or more. It was proved that destruction of isotropic materials occurs along the plane of action of maximum tangential stresses. Anisotropic materials are destroyed, depending on size of clearance between a roll and a jaw, both on the plane of action of the maximum tangential stresses and on the planes of least resistance.

MORPHOLOGY AND ELEMENT COMPOSITION POWDER ALLOY POWDER VNZH-95, OBTAINED BY ELECTROEROSION DISPERSION IN KEROSIN

Residence permits pseudo-alloys are used for the manufacture of cylinder parts, bushings, complex-shaped blanks with curved surfaces: gyroscope rotors, inertial masses, erosion-resistant electrodes, funnel for cumulative charges, biological protection from gamma radiation. Recycling of tungsten pseudo-alloys residence permit is relevant and necessary due to the shortage of tungsten. A promising method of processing waste into fine powders is the method of electroerosive dispersion (EED) that we have chosen. The purpose of the work is to study the morphology and elemental composition of the powder of the VNZh-95 pseudo-alloy obtained by electroerosive dispersion in kerosene. In order to process the waste of the W-Ni-Fe alloy into powder, we used waste in the form of chips from the core of the VNZh-95 pseudo-alloy (Ni ̶ 3.2-3.7, Fe ̶ 1.5-2.0, W ̶ the rest). Kerosene is used as a working fluid. The EED process was carried out on the installation for obtaining powders from conductive materials (patent for the invention of the Russian Federation No. 2449859). The process was carried out at a voltage on the electrodes of 100 ... 110 V, the capacitance of the discharge capacitors 50 μF and a pulse repetition rate of 120 ... 130 Hz. The microstructure of the samples (along the transverse section) was studied using a Quanta 200 3D electron-ion scanning microscope. The powder obtained by the EED method for waste of VNZh-95 alloy in kerosene consists of particles of regular spherical shape (or elliptical) and irregular shape (conglomerates). Microanalysis of particles of electroerosive powder of pseudo-alloy VNZh-95 was carried out using an EDAX energy-dispersive x-ray analyzer built into the Quanta 200 3D scanning electron microscope. As a result of studying the elemental composition of the VNZh-95 pseudo-alloy powder obtained by EED in kerosene, it was found that the main elements are tungsten, nickel, iron, carbon and oxygen.

Preparation and Study of the Properties of Aluminum Powders, Suitable for the Manufacture of Powder Electrodes

The results of the study of the shape, morphology and elemental composition of aluminum powder particles obtained in distilled water with the following electrical parameters of the electroerosive dispersion unit are presented: the capacity of discharge capacitors is 65 μF, voltage 100 V, pulse frequency 50 Hz. It is established that the powder consists of particles of regular spherical shape (or elliptical), irregular shape (conglomerates) and fragmentation, and the main elements of the powder are aluminum and oxygen. The obtained powder materials can be used for the manufacture of powder electrodes used in welding and surfacing of a wide range of parts.

Synthesis, Characterization, and In Vitro Drug Delivery of Chitosan-Silica Hybrid Microspheres for Bone Tissue Engineering

Chitosan-silica (CS-SiO2) hybrid microspheres were prepared through the combined process of sol-gel and emulsification-crosslinking. Their composition, morphology, in vitro bioactivity, and drug release behavior were investigated. The results showed that, when 20 wt% SiO2 was incorporated, the as-prepared CS-SiO2 hybrid microspheres exhibited a regular spherical shape, a high dispersity, and a uniform microstructure. Their average particle diameter was determined to be about 24.0 μm. The in situ deposited inorganic phase of the hybrid microspheres was identified as amorphous SiO2, and its actual content was determined by the TG analysis. As compared with the pure chitosan microspheres, the CS-SiO2 hybrid microspheres displayed a greatly improved in vitro bioactivity. Vancomycin hydrochloride (VH) was selected as a model drug. It was demonstrated that the CS-SiO2 hybrid microspheres presented a good capacity for both loading and sustained release of VH. Moreover, the increase of the SiO2 content efficiently slowed down the drug release rate of the CS-SiO2 hybrid microspheres.

Nanocrystallization of Anthocyanin Extract from Red-Fleshed Apple ′QN-5′ Improved Its Antioxidant Effect through Enhanced Stability and Activity under Stressful Conditions

Red-flesh apples are known as functional fruits because of their rich anthocyanin. The anthocyanin content of the red flesh apple cultivar ′QN-5′ we bred can reach 361 mg·kg−1 (FW), and showed higher scavenging capacity to DPPH radicals, hydroxyl radicals, and superoxide anion radicals, with scavenging rates of 80.0%, 54.0%, and 43.3%, respectively. We used this particular anthocyanin-rich ′QN-5′ apple as material to examine how nanocrystallization affects the antixodiant effect of anthocyanin. The anthocyanin extract was encapsulated with biocompatible zein to form zein-anthocyanin nanoparticles (ZANPs). Transmission electron microscopy (TEM) scanning showed that ZANPs had a regular spherical shape with an average diameter size of 50–60nm. When the ratio of the zein and the anthocyanin was 1:0.5, the results suggested that the encapsulation efficiency (EE) of the ZANPs could reach as high as 92.8%, and that scavenging rate for DPPH radicals was increased from 87.1% to 97.2% compared to the non-nanocrystallized anthocyanin extract. Interestingly, treatment under alkaline conditions (pH 9.0), high temperature (90 °C), and a storage time of 7 days could decrease the scavenging capacity of the ZANPs for DPPH radicals, but this scavenging capacity loss for ZANPs was significantly lower than that observed in the non-nanocrystallized anthocyanin, suggesting the higher stability of ZANPs is caused by encapsulation. These results would provide a theoretical basis for the application of the anthocyanin in scavenging free radicals under stress conditions.