EXPERIMENTAL STUDY OF THE MECHANICAL EFFECT OF BIO-LOADS ON PVC RECYCLING

With the increase in plastic waste, recycling becomes an urgent necessity to reduce and revalue it. PVC is one of the most widely used types of plastic in the world, and indeed it is among the most recycled. The effect of recycling on PVC or any other type of material is to reduce these characteristics, which also depends on the method by which it is recycled. Finding a way to increase the recyclability number of PVC by improving the mechanical characteristics will be an addition at the level of scientific research as well as at the industrial level. The addition of a bio-loading in the form of cow horns, coconut or chicken feathers on the rigid and flexible PVC with an experimental study of the results obtained allow to deduce the most adequate bio-loaded material to improve the mechanical characteristics after recycling. The experiments carried out on rigid and flexible PVC demonstrated the evolutions brought to PVC with and without loading after recycling The results obtained showed an improvement in the mechanical properties of rigid and flexible PVC with a natural bio-loading with the three fibers of coconut, cow horns and chicken feathers which enhance the environment, are very light and can be collected. directly from the waste with a large amount.

Effect of Excess Atomic Volume on Crack Evolution in a Deformed Iron Single Crystal

This paper presents a molecular dynamics study of how the localization and transfer of excess atomic volume by structural defects affects the evolution and self-healing of nanosized cracks in bcc iron single crystals under different mechanical loading conditions at room temperature. It is shown that deformation is initially accompanied by a local growth of the atomic volume at the crack tips. The crack growth behavior depends on whether the excess atomic volume can be transferred by structural defects from the crack tips to the free surface or other interfaces. If an edge crack is oriented with respect to the loading direction so that dislocations are not emitted from its tip or only twins are emitted, then the sample undergoes a brittle-ductile fracture. The transfer of the excess atomic volume by dislocations from the crack tips prevents the opening of edge cracks and is an effective healing mechanism for nanocracks in a mechanically loaded material.

Acid-Sphingomyelinase Triggered Fluorescently Labeled Sphingomyelin Containing Liposomes in Tumor Diagnosis after Radiation-Induced Stress

In liposomal delivery, a big question is how to release the loaded material into the correct place. Here, we will test the targeting and release abilities of our sphingomyelin-consisting liposome. A change in release parameters can be observed when sphingomyelin-containing liposome is treated with sphingomyelinase enzyme. Sphingomyelinase is known to be endogenously released from the different cells in stress situations. We assume the effective enzyme treatment will weaken the liposome making it also leakier. To test the release abilities of the SM-liposome, we developed several fluorescence-based experiments. In in vitro studies, we used molecular quenching to study the sphingomyelinase enzyme-based release from the liposomes. We could show that the enzyme treatment releases loaded fluorescent markers from sphingomyelin-containing liposomes. Moreover, the release correlated with used enzymatic activities. We studied whether the stress-related enzyme expression is increased if the cells are treated with radiation as a stress inducer. It appeared that the radiation caused increased enzymatic activity. We studied our liposomes’ biodistribution in the animal tumor model when the tumor was under radiation stress. Increased targeting of the fluorescent marker loaded to our liposomes could be found on the site of cancer. The liposomal targeting in vivo could be improved by radiation. Based on our studies, we propose sphingomyelin-containing liposomes can be used as a controlled release system sensitive to cell stress.

Numerical Study and Experimental Validation of Deformation of FCC CuAl Single Crystal Obtained by Additive Manufacturing

The importance of taking into account directional solidification of grains formed during 3D printing is determined by a substantial influence of their crystallographic orientation on the mechanical properties of a loaded material. This issue is studied in the present study using molecular dynamics simulations. The compression of an FCC single crystal of aluminum bronze was performed along the <111> axis. A Ni single crystal, which is characterized by higher stacking fault energy (SFE) than aluminum bronze, was also considered. It was found that the first dislocations started to move earlier in the material with lower SFE, in which the slip of two Shockley partials was observed. In the case of the material with higher SFE, the slip of a full dislocation occurred via successive splitting of its segments into partial dislocations. Regardless of the SFE value, the deformation was primarily occurred by means of the formation of dislocation complexes involved stair-rod dislocations and partial dislocations on adjacent slip planes. Hardening and softening segments of the calculated stress–strain curve were shown to correspond to the periods of hindering of dislocations at dislocation pileups and dislocation movement between them. The simulation results well agree with the experimental findings.

Controllable synthesis of hollow spherical nickel chalcogenide (NiS2 and NiSe2) decorated with graphene for efficient supercapacitor electrodes

The carbon-loaded material by introducing graphite oxide with different mass fractions through a l-cysteine-assisted facile hydrothermal method was synthesized. The specific capacitance was increased with GO and the rate performance was improved.

Selective Extraction of REEs Thanks to One-Pot Silica Hybrid Materials

The importance of rare-earth elements (REEs) in the global economy is rapidly growing, since they are essential to many advanced technologies. Therefore, the development of more performant separation procedures for REEs has become necessary. In the present study, we used silica hybrid materials (SHMs), which were synthesized by an all-in-one approach that allows the direct incorporation of desired functional groups, as sorbent material. Promising results were obtained for the extraction capacities of diglycolamide-functionalized materials. Under the tested conditions, they showed high efficiency (Nd uptake capacity of about 25 mg per g of material) and high selectivity toward REEs from a simulated NdFeB magnet leachate. For these materials, Nd recovery after extraction was achieved with an efficiency of 80% by contacting the loaded material with distilled water at moderate pH (6.5).

Ultrasonic VHCF Tests on Very Large Specimens with Risk-Volume Up to 5000 mm3

The research on the size-effects in Very-High-Cycle Fatigue (VHCF) has recently drawn the attention of several scholars. The fatigue cracks in VHCF originate from the largest defect present within the loaded material volume (risk-volume) and the larger the risk-volume, the larger the probability of critical defects affecting the VHCF response (size-effect). Many models have been proposed in the literature to deal with size-effects in VHCF. However, the proposed models cannot be validated on full-scale components, since VHCF tests are typically carried out with ultrasonic fatigue testing machines. The authors have proposed a specimen geometry, the so-called Gaussian specimens, to enlarge as much as possible the risk-volume in ultrasonic VHCF tests. In this study, fully reversed tension–compression ultrasonic VHCF tests up to 109 cycles were carried out on AISI H13 steel Gaussian specimens with a risk-volume of 5000 mm3, two times larger than the largest tested in the literature. The stress distribution and the absence of bending loads were verified with strain gages, proving that VHCF tests on risk-volumes of 5000 mm3 can be reliably carried out. Ultrasonic VHCF tests were also carried out on small hourglass specimens, confirming that larger risk-volumes allow for a more reliable design against VHCF failures.

Cinnamaldehyde-loaded chitosan nanoparticles: characterization and antimicrobial activity

Due to its wide spectrum activity and low toxicity, chitosan has shown to be a promising molecule to be applied in food science and technology. Meanwhile, cinnamaldehyde (the main component in cinnamon flavor) has shown potential uses as a strong antimicrobial compound. To improve the antimicrobial activity of chitosan, we have prepared N-acylated chitosan nanoparticles, with cinnamaldehyde as acylating reagent. The properties of the modified material were compared against the ones of the unmodified chitosan nanoparticles. Modification of the material was characterized by means of FT-IR spectroscopy with the identification of the imine group formed due to the addition of cinnamaldehyde (soft band appearance in the range of 1630-1660 cm-1 ). Meanwhile, 1H NMR analysis was used to quantify the modification. Nanoparticles of both, the modified and the unmodified chitosan, were characterized by TEM and DLS analysis showing a higher diameter size and a reduced zeta potential for the cinnamaldehyde loaded material than the chitosan nanoparticles. Finally, their activity was tested against E. coli and L. monocytogenes by measuring the minimal inhibitory concentration, showing a greater activity when the nanoparticles were functionalized (with an observed increase of the activity with the higher loading of cinnamaldehyde). This works evidence that the N-acylated chitosan nanoparticles have promising and potential use in food preservation.

Synthesis of high surface area magnesia by using walnut shell as a template

In the present study, high surface area amorphous magnesia was synthesized using walnut shell as a template. This green, simple and useful synthetic protocol was based on the precipitation of magnesium nitrate on biomass in an aqueous phase, followed by calcination. Materials were characterized using X-ray diffraction, scanning electron microscopy (SEM) and N2 adsorption/desorption porosimetry, and the results exhibited high surface area for magnesium oxide. Furthermore, the pore size and surface area of these mesoporous materials can be adjusted by varying the biomass/magnesium nitrate ratio. In addition, magnesium oxide was studied as the support of palladium nanoparticles for the aerobic oxidation of alcohols. We have found out that the resulting Pd-loaded material acts as an effective catalytic system for the aerobic oxidation of benzylic and aliphatic alcohols. The catalyst can be recovered and reused three times without loss of activity. Also, to test the catalytic activity of magnesium oxides as a solid catalyst, we selected Meerwein-Ponndorf-Verley reduction of cyclohexanone with 2-propanol over different magnesium oxides.