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Recently we have developed polymer/ceramic composite coatings based on poly(vinyl butyral), hydroxyapatite and zinc oxide-based nanostructured powders (PVB, HAP:Co and ZnO:Co, respectively). Prepared composite coatings showed good both adhesions to metal and glass surfaces and camouflage properties, thus can be used to improve combat capability of military equipment. An essential demand of new materials in the military industry is to be multifunctional. Accordingly, the aim of this study was to examine corrosion activity of the PVB/ZnO:Co and PVB/HAP:Co coatings in saline solution as a function of immersion time. The ZnO:Co and HAP:Co nanostructured powders were synthesized by hydrothermal processing of a precipitate. To adjust optical properties, synthesized powders were annealed at 400, 800 and 1000 °C. Annealed powders were mixed with PVB: each powder was dispersed in ethanol with the aid of an ultrasonic probe, successively PVB powder was added in dispersion, in 10 wt.% regard to ethanol, and stirred on a mechanical stirrer to completely dissolve. Prepared solution was coated on stainless steel substrate and dried at room temperature for 72 hours to form solid coating. The corrosion activity of the coatings was measured by potentiodynamic polarization technique in the potential range from -0.8 to -0.2 V vs SCE, with the scan rate of 10mVs-1. The measurements were performed using a conventional three-electrode cell in 3% NaCl water solution as the electrolyte. Platinum foil, a standard calomel electrode (SCE) and coated stainless steel were used as the counter, reference and working electrode, respectively. We found that all examined coatings have lower corrosion activity than bare stainless steel or stainless steel coated with pure PVB. Differences in corrosion activity between the coatings are explained by different textural and optoelectronic properties of ceramic powders modified by the annealing procedure.

Thermal decomposition of ammonium perchlorate (AP), as a high energy oxidizer in composite solid rocket propellants (CSRP), greatly affects the burning rate of the propellant. This paper summarizes the results of a study of the synergistic catalytic activity of nano-CuO/Fe2O3 nanoparticles on thermal decomposition of AP. AP micro-particles are efficiently encapsulated with 1 and 5 wt.% of nano-CuO and/or nano-Fe2O3 nanoparticles by the fast-crash solvent-antisolvent technique. The efficiency of the encapsulation method was confirmed using FT-IR spectroscopy. Morphological characterization, performed using SEM-EDS microscopy, showed that encapsulation provides recrystallization and deagglomeration of AP and uniform nano-catalyst distribution. The catalytic efficiency of nano-CuO/ nano-Fe2O3 nanoparticles on the thermal decomposition of AP was investigated using DSC, and an increase in released heat was observed from 1453 to 1628 J/g. The catalytic activities of performed nano-catalysts were proven by decreasing the HTD and merging with the low decomposition temperature peak. The highest catalytic effect was obtained after encapsulating with 5 wt.% of nano-CuO and nano-Fe2O3 combined in a 50/50 mass ratio due to multiple mechanisms of catalytic activity of nano-Fe2O3. The effect of AP encapsulation with nano-Fe2O3 on the burning rate of CSRP was investigated and the obtained results showed a favorable effect on the combustion rate law. © 2023 Łukasiewicz Research Network – Institute of Industrial Organic Chemistry, Poland

The aim of this study was to investigate the possibility to use the industrial explosive Amonex, which belongs to a group of low-to-middle detonation velocity explosives, for welding of metallic materials. It consists of ammonium nitrate and TNT as energetic components and other inert ingredients and has a powdery consistency, easily applicable in a desirable layer over the metal plates to be welded. Within this research, Amonex was applied to weld plates of aluminium Al 2024 and steel 1.0216 (according to EN 10027-2). The procedure of welding was carried out in the configuration of parallel plates, and afterwards the welded joint was examined. Ultrasonic method and infrared imaging were used as non-destructive techniques, and then the samples were cut from the welded plate using water-jet, in order to perform microscopic analyses of the cross-section in the joint area. It was observed that a good-quality welded joint was obtained, and that the selected explosive may find further application in this area. However, certain nonwelded area was observed, encouraging future modification of the welding procedure set-up., Cilj ove studije je ispitivanje mogućnosti upotrebe industrijskog eksploziva Amonex, koji pripada grupi eksploziva male-do-srednje brzine detonacije, za zavarivanje metalnih materijala. Ovaj eksploziv se sastoji od amonijum nitrata i TNT-a kao energetskih komponenti i drugih inertnih sastojaka, ima praškastu strukturu i lako se nanosi u željenom sloju preko metalnih ploča koje se zavaruju. U okviru ovog istraživanja, Amonex je primenjen na zavarenim pločama aluminijuma Al 2024 i čelika 1.0216 (oznake prema EN 10027-2). Postupak zavarivanja izveden je na paralelno postavljenim pločama, nakon čega je izvršen pregled zavarenog spoja. Kao metode IBR korišćene su ultrazvučna metoda i termovizijsko ispitivanje. Primenom vodenog mlaza iz zavarene ploče su isečeni uzorci u cilju ispitivanja mikrostrukture poprečnog preseka zavarenog spoja. Uočeno je da je dobijen kvalitetan zavareni spoj, te da odabrani eksploziv može naći dalju primenu u ovoj oblasti. Međutim, takođe su uočene i određene površine nezavarenog područja, što je nametnulo potrebu za izmenama postavke ovog postupka zavarivanja.

Besides their application in munitions and armaments, explosives have a significant role in industrial applications, such as cladding or welding of metal plates. In the process of explosion welding, the energy of explosive detonation is used to achieve a metallurgical bond between two metal components, which are metallurgically compatible, but also those that are non-weldable by conventional methods. For this purpose, most often explosives of low values of detonation velocity are used, in order to avoid severe damage to the processed metal plates. The aim of this study was to investigate the possibility to use the industrial explosive Amonex, which belongs to a group of low-to-middle detonation velocity explosives, for welding of metallic materials. It consists of ammonium nitrate and TNT as energetic components and other inert ingredients and has a powdery consistency, easily applicable in a desirable layer over the metal plates to be welded. Within this research, Amonex was applied to weld plates of aluminium Al 2024 and steel Č0345. Besides the initial data on the used metal plates, the main properties of the used explosives are also given, since based on these properties the needed quantity of explosive was estimated. The procedure of welding was carried out in the configuration of parallel plates, and afterward the welded joint was examined. Ultrasonic method and chemical penetrants were used as non-destructive techniques, and then the samples were cut from the welded plate using water-jet, in order to perform microscopic analyses on the cross-section and to determine the indentation hardness in the area of the joint. It was observed that a good-quality welded joint was obtained, and that the selected explosive may find further application in this area.

Explosive plating, or welding, is a process where part of the kinetic energy of the detonation of a certain amount of civil explosive material is used to accelerate the plate, which will form a welded joint upon an oblique impact on a stationary plate. The conditions that must be met to achieve a good weld are determined by welding criteria. Today, the most commonly used welding criteria are based on the speed of the collision point and the collision angle. In this paper a research is presented on explosion welding of two different steels and on quality of the obtained welded joint. Carbon steel and spring steel were welded using Amonex 4 explosive in different quantities. Basic characterization of the explosive was carried out: bulk density and detonation velocity were determined. Quality of the welded joint was inspected using the ultrasonic method. Possible intermetallic zones at the joint site created by the effect of increased temperature were examined by optical and scanning electron microscopy. Fracture toughness of the welded plates was determined, as well as hardness. The achieved experimental results were compared to theoretical predictions.

The para-aramid fibres (Kevlar, Twaron, Kolon) are high performance polymeric fibres characterized by their high tenacity, strength to weight ratio and impact resistance. They are used for the soft body armour structures in ballistics and for the manufacture of parts in aerospace and automotive industry. In this study, the specimens were made from the two-layered Kolon fabrics impregnated with epoxy resin where some silicon carbide (SiC) microparticles or SiC nanofibres were added as reinforcement. These composite specimens were fabricated by hot compression and curing of epoxy resin. Despite their good mechanical strength it is a well-known fact that the mechanical properties of epoxy resins are affected by moisture absorption. The tensile and impact properties of the untreated specimens were compared with the ones that underwent water absorption in the duration of 72h (immersion or humidity) followed by desorption. The immersion of the specimens in water and the exposure to high humidity (70%) were completed in accordance with the ISO 62 standard while the tensile test was performed according to the ASTM D 3039 standard. Furthermore, the tensile test simulation of the Kolon/epoxy composite by using software Abaqus® was accomplished. For the determination of the absorbed impact energy and the impact toughness of the composite specimens, an impact test was performed by using the Charpy impact pendulum in accordance with the ASTM D5942 standard.

As one of transition metal dichalogenides, tungsten disulphide (WS2) is well known for its solid lubricating behavior, but besides this feature, it exhibits extraordinary thermal stability and mechanical resistance. The outstanding mechanical strength of WS2 is most pronounced when it comes in form of multi-layer hollow nanoparticles and nanotubes: inorganic fullerene-like nanoparticles and inorganic nanotubes, denoted as IF-WS2 and INT-WS2, respectively. These structures have extraordinary shock resistance properties, pressure and heat resistance, that can be exploited for a variety of applications. They have been studied as reinforcing fillers of various polymers, but they might be also added as reinforcement of matrix in more complex composites, like CFRPs. Our research aimed to examine their reinforcing effect on laminated composites based on aramid fabric and poly(vinyl butyral), PVB, intended for demanding applications: in personal protection equipment, ballistic protection, sports equipment, automotive, nautical and aircraft engineering. WS2 nanostructures have been incorporated in PVB by temporary dissolving in ethanol, by ultrasonication and intensive mechanical mixing. After impregnation of aramid fabrics ethanol would evaporate, and layers of aramid with thermoplastic binder PVB would be integrated by hot pressing. SEM analysis confirms the uniform distribution of WS2 nanostructures in the prepared composite material. DSC analysis reveals the effect of WS2 addition on thermal resistance of the new material, while PVB/aramid mechanical resistance was examined using DMA, impact test and tensile test. IF- WS2 has imported higher thermal resistance and ductility improvement, while INT-WS2 has significantly improved tensile and impact strength of the composite.

This research considers a possibility to enhance the mechanical and spectrophotometric properties of a military camouflage cotton textile by applying a nano silver/poly(vinyl butyral), PVB, impregnation. Silver is known for its unique optical, electrical, thermal properties and antimicrobial activity[1]. PVB is chosen as a good impregnating matrix, being a thermoplastic elastomer with good adhesion behavior, resistant to wetting [2]. Impregnated fabric samples were examined regarding spectrophotometric properties and mechanical abrasion resistance. To achieve low visibility, besides being painted to match the colors of the environment, a surface must scatter light, so it should have a matte, low gloss coating [3, 4]. Diffuse reflectance and gloss are related, and from a spectral point of view, scattering properties are relevant for surface appearance [5]. Certain nanostructures may alter this feature.

A possibility was examined to enhance carbon-epoxy laminated composite mechanical properties by introducing a small concentration of reinforcing nanostructures - multi-wall onion-shaped fullerene-like nanoparticles of tungsten disulfide IF-WS2, and its multi-layer hollow nanotubes, INT-WS2, both known for their outstanding thermal, chemical, and mechanical resistance. Composite structures were prepared using a unidirectional prepreg of strong carbon fibers and epoxy resin, poly (vinyl butyral) solution in ethanol with ultrasonically dispersed WS2 nanostructures in it. Particle size analysis has been performed to evaluate the quality of IF-WS2 nanoparticles. SEM/EDS analysis was applied to observe the nanostructures, their dispersion in the composite, and the fracture zone after mechanical resistance tests of the prepared composite samples. Thorough mechanical tests were performed on a set of specimens with different fiber orientations: tensile test, bending test, and interlaminar shear test. The encouraging results were obtained, indicating that these newly designed light-weight composites are applicable for the automotive and nautical industry, unmanned aerial vehicles, and military aircrafts.

Tehničko rešenje Mobilni bioreaktor za dobijanje imobilisanih mikroorganizama za bioremedijaciju, se odnosi na nov i ekonomičan postupak u tehnologiji bioremedijacije zemljišta zagadjenih organskim supstancama, prvenstveno naftom i naftnim derivatima. Ovom tehnologijom se rešava problem izlivene nafte, njenih derivata i pratećih zagadjivača pomoću mikroorganizama sa lica mesta na samom mestu zagadjenja. Mobilni bioreaktor je pokretan tako da se na samom mestu kontaminacije umnožava tj. proizvodi velika količina specifičnih mikroorganizama prirodno prisutnih u tom ekosistemu koji zagadjujuću supstancu razlažu i koriste kao hranu. U bioreaktoru se ti mikroorganizmi dodatno optimizuju za konkretno zagadjenje.

In this study, volatile compounds were analyzed in five samples of home-made spirit beverage made by the distillation of fermented fruits of cornelian cherry (Cornus mas L.). The major volatile compounds, besides ethanol, identified and quantified were: methanol, acetaldehyde, I-propanol, ethyl acetate, 2-methyl-1-propanol, 1-butanol, amyl alcohols, 1-hexanol and 2-phenyl-ethanol, The minor volatiles were submitted to liquid liquid extraction with dichloromethane and analyzed by gas chromatography and gas chromatography/ /mass spectrometry (GC/MS). A total of 84 compounds were identified. The most abundant compounds were straight-chain free fatty acids, ethyl esters of C(6)-C(18) acids, limonene, 2-phenylethanol and 4-ethylphenol. Most of the compounds found in the "Drenja" spirits investigated in this study arc similar to those present in other alcoholic beverages., U radu su analizirane isparljive komponente u pet uzoraka alkoholnih pića, domaće izrade, dobijenih destilacijom fermentisanih plodova drenjine (Cornus mas L.). Glavna isparljiva jedinjenja, koja su određena i kvantifikovana, su: metanol, 1-propanol, etil-acetat, 2-metil-1-propanol, 1-butanol, izoamil-alkoholi, 1-heksanol i 2-feniletanol. Manje zastupljena isparljiva jedinjenja su ekstrahovana dihlormetanom i analizirana kombinacijom gasne hromatografije i masene spektrometrije (GC/MS). Identifikovana su ukupno 84 jedinjenja. Najzastupljenija jedinjenja bila su etil estri masnih kiselina sa C6-C18, slobodne masne kiseline, limonen, 2-feniletanol i 4-etilfenol. Većina jedinjenja nađena u 'drenji' su slična onima koja su prisutna i u drugim alkoholnim pićima.