Teodora Zecheru

Biomimetic potential of some methacrylate-based copolymers: A comparative study

Preparation of new biocompatible materials for bone recovery has consistently gained interest in the last few decades. Special attention was given to polymers that contain negatively charged groups, such as phosphate, carboxyl, and sulfonic groups toward calcification. This present paper work demonstrates that other functional groups present also potential application in bone pathology. New copolymers of 2-hydroxyethyl methacrylate with diallyldimethylammonium chloride (DADMAC), glycidyl methacrylate (GlyMA), methacrylic acid (MAA), 2-methacryloyloxymethyl acetoacetate (MOEAA), 2-methacryloyloxyethyltriethylammonium chloride (MOETAC), and tetrahydrofurfuryl methacrylate (THFMA) were obtained. The copolymers were characterized by FTIR, swelling potential, and they were submitted to in vitro tests for calcification and cytotoxicity evaluation. GlyMA and MOETAC-containing copolymers show promising results for further in vivo mineralization tests, as a potential alternative to the classical bone grafts, in bone tissue engineering.

Temperature measurements of magnesium- and aluminum-based flares

Experimental researches were performed in order to determine the combustion temperatures and the visible and infrared screening performances of two pyrotechnic compositions used in decoy flare systems. Morphostructural and morphochemical analyses of the combustion solid products have been correlated with the combustion temperature. For the experimental studies, visible and infrared thermography have been employed, together with dedicated software. The comparative measurements indicated that the thermovision camera enables the acquisition of more accurate results versus the optical pyrometer in terms of data processing, and that the aluminum/polyhalogenated compounds–compositions present visible and infrared screening performances superior to those based on magnesium/polyhalogenated compounds.

Thermal and spectroscopic measurements of some energetic compositions and corresponding aerosols obtained

Studies on specific thermochemical processes contribute to the understanding of combustion processes and, meanwhile, to the calculus of the safety characteristics and the systems design parameters. In this paper, five different compositions have been studied through TGA and DTA. The reaction rate constants and the activation energies have been determined. Also, the solid combustion products obtained have been evaluated through SEM, EDX, and XPS. Nonisothermal kinetic analyses performed yield results that prove an important difference among the first fire compositions, where the activation energies are considerable, up to 400 kJ/mol, in comparison with the activation energies of the flare compositions, which are lower, 150–250 kJ/mol.

Potential Use in Forensics of a Novel Hybrid Gelatin—Dynamic Impact Assessment†

Ballistic gelatin as simulant of the human body and organs is a support in forensics. After having obtained very good results for a new gelatin‐based composite in terms of physicochemical and rheological properties, this study focused on this materials mechanical behavior during stabbing and shooting versus bovine and porcine organs and standard ballistic gelatin. The hybrid gelatin has a predominantly elastic behavior at 23°C, whereas the elastic modulus becomes practically constant in the 10–0.1 Hz frequency range. In terms of stabbing behavior, the small variations obtained between porcine organs and surrogate are below 5%, the perforation indicating a good similarity. From the ballistic test results using 10 × 28T rubber balls, it has been seen that the hybrid ballistic gelatin conducts to more reliable and reproducible values of perforation/penetration versus standard gelatin, making from it a real candidate for use in forensic tests.

Airflow Modeling and Simulation Required in CBRN Collective Protection Design

Abstract Many CBRN agents are very difficult to detect and identify, due to the fact that most technologies, equipment and materials used for their obtainment have also commercial applications. One possibility to counteract such threats, both for military and civilians, is to use systems of collective protection (COLPRO), which must be manufactured from materials that can withstand not only the action of CBRN agents, but, as much as possible, toxic industrial materials (TIMs). The computational fluid dynamics (CFD) study of the atmosphere in the neighbourhood of the COLPRO tent and the air flow dynamics inside the tent give all the necessary data regarding the effect of air circulation on the entire COLPRO system. Based on this study, a favourable orientation of the COLPRO tent may be established relatively to the strategic position of the troops or the civilian groups, versus statistical wind speed, direction and charge.

Novel formulations of ballistic gelatin. 1. Rheological properties

Ballistic gelatin is the simulant of the human body during field tests in forensics and other related fields, due to its physical and mechanical similarities to human trunk and organs. Since the ballistic gelatin used in present has important issues to overcome, an alternative approach is the use of gelatin-polymer composites, where a key factor is the insertion of biocompatible materials, which replicate accurately the human tissues. In order to be able to obtain an improved material in terms of mechanical performances by an easy industrial-scale technology, before the verification of the ballistic parameters by shooting in agreement with military standards, one of the best and cheapest solutions is to perform a thorough check of their rheological properties, in standard conditions.

Design and Performance Characteristics of New Female Bulletproof Vests

Abstract The new female bulletproof vest was designed with a superior female fit, this body armour providing a good balance between protection and comfort. One of the new issues in designing the female ballistic vest consists in taking into account the shape and bras size of Romanian female body, based on anthropometric survey using the 3D scanner technology. This bulletproof vest will provide comfort and mobility with the same or superior ballistic resistance properties versus standard body armour equipment. The ballistic performance parameters have been evaluated, in agreement with the international standards, in specialized laboratories of the Romanian MoD.

Influence of the Shock Wave on the Hybrid Ballistic Gelatin

Abstract Forensic ballistic tests involve the use of various ballistic gelatins and soaps. Their use is restrained due to several important factors: their synthesis strategy, their availability at room temperature and their rapid degradation even when kept in cold places. The importance of human torso surrogates translates in the facility to verify various ballistic factors impact, such as shock wave or fragments. In the first case, the use of piezoelectric transducers and accelerometers inside torso surrogates helps in defining safety distances and materials for individual protection equipment.

Polymer Composite Materials And Applications For Chemical Protection Equipments

Abstract The polymer composite materials properties are clearly determined by their constituent properties and by the micro-structural configuration. Additives and modifiers ingredients can expand the usefulness of the polymeric matrix, enhance the processability or extend composite durability. The fibres are mainly responsible for the performance changing (strength and stiffness properties). The least structurally demanding cases is the arrangement of fibres randomly in polymeric matrix, when equal strength is achieved in all directions. Fibre reinforced polymer materials can be successfully used in a wide range of applications and can significantly improve the characteristics of chemical protection equipments and foster the development of new ones with superior features.

Triiodophenyl acrylate-based microbeads find important use in the medical field

Preparation of polymeric micro- and nanoparticles has significantly become an effective approach for achieving efficient drug targeting to tumour tissues. A promising solution could be the use of a radio-opaque polymeric system carrying iodine groups. In this context, radio-opaque polymeric microparticles based on methyl methacrylate (MMA) and an 2,4,6-triiodophenyl acrylate (TIPA) were synthesised by suspension and emulsion polymerisation techniques. Various compositions of p(MMA-co-TIPA) were physico-chemically and biologically characterised through FTIR-ATR, SEM, EDX, in vitro biocompatibility and X-ray measurements. These copolymers exhibit good in vitro cell compatibility together with good X-ray visibility so they are good candidates for tumour detection and imaging.