Concept MSBS GROT Rifle Upper Receiver Shield to Protect Against Foreign Objects

This paper presents a concept for shielding the MSBS (Modular Firearms System) Grot rifle upper receiver against foreign objects. The concept guidelines involve feedback from Grot operators concerning the regular operation of the rifle plus an extensive analysis of desktop patent research into foreign debris shields (or dust shields) for protection of the upper receiver interior in firearms. The completed patent desktop research included solutions used with automatic, semi-automatic and non-automatic firearms. The research work drove the formulation of the requirements for an upper receiver dust shield for the 5.56 mm calibre MSBS Grot rifle as part of the ongoing improvement process. This paper presents three concepts of the carrier charging handle assembly dust shield (for the protection of the upper receiver against foreign objects) for the MSBS-5.56 rifle system. The concepts described vary in terms of the level of structural complexity of the dust shield, and the extent of the modifications required to the upper receiver of the rifle. With test units of the upper receiver dust shield manufactured and comparative tests completed on the three concepts, the version selected should be the one which improves the protection of the rifle internals from foreign objects found in the local environment, including sand, clay, silt, and mud, the latter being an aqueous suspension of these particles.

Devising the technology for localizing environmental pollution during fires at spontaneous landfills and testing it in the laboratory

This paper reports an analysis of current issues related to storing solid household waste, and, specifically, the problem of environmental pollution when unsorted solid household waste (SHW) is ignited. A technology has been developed to improve environmental safety and ensure a reduction in the anthropogenic load on the atmosphere, hydrosphere, and lithosphere in the event of fires at the sites of solid waste storage. The operation of the proposed equipment, taking into consideration all the provided operating modes and additional options, is energy-saving and automated (or semi-automatic), which makes it especially relevant under modern conditions. The technology significantly improves the efficiency of the processes to eliminate the ignition of SHW and localize their environmental consequences for the territories adjacent to landfills. Laboratory tests were carried out, which proved the effectiveness of practical application for the designed equipment of a new environmentally active adsorption mixture for the purpose of cleaning the waste filtrate, as well as its use for the formation of an anti-filtration screen in the mound of SHW. Experiments have shown that the tested sample of the aqueous suspension of the proposed environmentally active mixture adsorbs calcium (by 92 %), overall iron (by 91 %), overall phosphorus (by 75 %), zinc (by 31 %), and ammonium (by 19 %). This leads to a decrease in the overall toxicity of the solution and indicates the possibility of improving the environmental safety of waste fires when operating the proposed technical solution by purifying the filtrate released during fires in landfills. The reported results, specifically, the technology for localizing the environmental consequences of uncontrolled waste ignition could be used in the process of modernizing the technical support for sanitary treatment schemes in urban areas.

Zinc sulphate or zinc nanoparticle applications to leaves of green beans

The green bean (Phaseolus vulgaris L.) is a very widely grown food crop that contributes significantly to human dietary needs in many countries due to its high content of protein. This study evaluates foliar applications of ZnSO4 versus that of zinc oxide nanoparticles (ZnO NPs) to leaves of the green bean cv. ‘Strike’ and records the plant responses in terms of Zn uptake and concentrations of photosynthetic pigments and bioactive compounds. The experiment was conducted under greenhouse conditions in Chihuahua, Mexico, with a completely randomised experimental design with 10 replicates. The two treatments were foliar applications of either an aqueous solution of ZnSO4 or an aqueous suspension of ZnO NPs (both 150 mg · L−1). The application of ZnO NPs significantly increased concentrations of Zn2+ in the leaflets, roots, stems and pods of chlorophylls a and b (values 15.40 μg · g−1 and 11.64 μg · g−1, respectively). Sucrose concentration was also increased by Zn2+ applications, but no differences were found in total phenols (TP), total flavonoids (TFl) or antioxidant capacity (AC). In the pods and seeds, Zn2+ application left sucrose and TFl concentrations unchanged, but the TP increase was significant. The AC was affected by both zinc sources and only in the pods. The applications of ZnSO4 or ZnO NPs significantly increased the biomass accumulation (79.10 g · p−1 and 84.70 g · p−1 DW) and yield (55.64 g · p−1 and 53.80 g · p−1 FW). These results suggest that the application of ZnO NPs could represent a worthwhile biofortification strategy in the commercial production of green bean cv. ‘Strike’.

PROMISING COMPOSITE MATERIALS BASED ON NANOSCALE APATITE WITH GELATIN AS A BINDING AGENT

Порошки наноразмерных гидроксиапатита и фторапатита синтезированы методом осаждения из растворов. В качестве связующего вещества использован пищевой желатин. Такая композиция имеет высокую адгезию на материалах различной природы и пористости. Получены также пористые пленки и гранулы с развитой удельной поверхностью. Рассмотрены их микроструктуры. Изучена возможность использования коллоидной суспензии и водной суспензии кристаллического апатита в сочетании с раствором желатина в качестве биоактивного материала, как для создания покрытий, так и получения гранул. Установлено, что использование порошка апатита совместно с желатином позволяет существенно сократить сроки формирования биоактивного покрытия и значительно повысить его адгезионную прочность. Сопоставлены получаемые гранулы апатита по размерам в зависимости от концентрации желатина в водном растворе. На разработанные биоактивные покрытия и гранулированный материал на основе наноразмерного апатита со связующим агентом поданы заявки на патент. Nanoscale hydroxyapatite and fluorapatite powders were synthesized by precipitation from solutions. Food gelatin is used as a binder. This composition has a high adhesion on materials of different nature and porosity. Porous films and granules with a developed specific surface area were also obtained. Their microstructures are considered. The possibility of using a colloidal suspension and an aqueous suspension of crystalline apatite in combination with a gelatin solution as a bioactive material, both for creating coatings and obtaining granules, has been studied. It is established that the use of apatite powder together with gelatin can significantly reduce the time of formation of a bioactive coating and significantly increase its adhesive strength. The obtained apatite granules are compared in size depending on the concentration of gelatin in an aqueous solution. Patent applications have been filed for the developed bioactive coatings and granular material based on nanoscale apatite with a binding agent.

SEPARATION OF PARTICLES IN POLYDISPERSE NANOSUSPENSION IN THE LASER RADIATION FIELD

На основе стационарного решения уравнения диффузии изучена сепарация наночастиц в прозрачной полидисперсной водной суспензии с различными типами распределений по размерам под действием силы светового давления, возникающей в поле лазерного излучения интенсивностью 0,5 - 500 кВт/см. Установлено, что на дно кюветы преимущественно будут осаждаться частицы радиусом более 100 нм, а концентрация более мелких наночастиц во всем объеме суспензии останется без изменений. В случае симметричного начальное распределения наночастиц по размерам воздействие интенсивного светового пучка на суспензию приводит к нарушению симметрии кривой функции распределения, а также смещению максимума в область меньших размеров частиц на облучаемой поверхности. Если начальное распределение по размерам имеет несимметричный характер, исходное одномодовое распределение частиц по размерам трансформируется в двумодовое. Данная методика может быть использована для выделения наночастиц определенных размеров в зависимости от плотности мощности излучения. On the basis of a stationary solution of a diffusion equation separation of nanoparticles in a transparent polydisperse aqueous suspension with different types of size distributions was studied under the action of the light pressure arising in the laser radiation field with the intensity of 0,5 - 500 kW/cm. It was found that particles with a radius of more than 100 nm will mainly be precipitated at the bottom of the cell, and the concentration of smaller nanoparticles in the entire volume of the suspension will remain unchanged. In the case of a symmetrical initial distribution of nanoparticles size, the effect of a light beam with high intensity on the suspension leads to a violation of the symmetry of the distribution function curve, as well as a shift of the maximum to the region of smaller particle sizes on the irradiated surface. If the initial size distribution is asymmetric, the initial single-mode particle size distribution is transformed into a two-mode one. This technique can be used to isolate nanoparticles of certain sizes depending on the power density of the radiation.

Effect of Nanocellulose in Cement Systems

Cellulose, the one of the most abundant biomaterials available in nature, is a polymer with cellobiose as the smallest repeating unit, with a degree of polymerization that can go up to 1000 for wood cellulose. The strength-to-weight ratio of nanocellulose is eight times greater than steel (Patchiya Phanthong et al). Nanocellulose in suspension (NCS) at a varied concentration helps increase properties of cement without changing the density of the cement slurry. Being mindful of challenges in oil and gas wells, efforts were made to enhance cement properties using nanocellulose within conventional and water-extended cement systems. Samples of 15.8-ppg conventional and 12 ppg water-extended cements were prepared by varying the proportion of nanocellulose within an aqueous suspension. Rheology, sedimentation, compressive strength and mechanical properties were analyzed for a conventional 15.8-ppg cement system with varying NCS proportions of 0, 2, 4, and 5% by weight of cement (BWOC). Similar work was performed for a 12 ppg water-extended cement system by varying NCS differently in proportions of 0, 5, 10, and 20% BWOC. Two-inch cubes were set at 170°F for 24 hours for each sample. They were crushed using hydraulic crush compressive strength equipment, and the force used to break the sample was recorded. Compressive strength for this cement system was measured to be 2450, 3250, 3450, and 3875 psi, respectively, for samples with 0, 2, 4, and 5% BWOC concentrations of NCS. An increase in the strength of cement with an increase in NCS percentage was observed for the 15.8-ppg slurry design, which may be attributed to the size and shape of the NCS. However, similar study carried out with 12 ppg water extended slurries showed decrease in overall compressive strength. Nano-sized particles fill the pores within the sample, impacting structural network development. Additionally, cellulose, having a fiber-like structure, may provide inter-particulate reinforcement. Based on the results of the 15.8-ppg cement system and the high tensile strength of nanocellulose, it can be determined that NCS has a positive effect for increasing mechanical properties. By applying nanocellulose, a tailored cement system (dependable barrier) can be designed to minimize risk and maximize production from oil and gas wells. Nanocellulose is of increasing interest for a range of applications relevant to the fields of material science and biomedical engineering because of its renewable nature, anisotropic shape, excellent mechanical properties, good biocompatibility, tailorable surface chemistry, and interesting optical properties. Low-volume NCS additions can alter the structure of the cured cement system and increase its mechanical properties. This reinforcing mechanism may provide a new opportunity for achieving higher strength cementitious materials.

Direct Foliar Application of dsRNA Derived From the Full-Length Gene of NSs of Groundnut Bud Necrosis Virus Limits Virus Accumulation and Symptom Expression

Groundnut bud necrosis virus (GBNV) is the most significant member of the genus Orthotospovirus occurring in the Indian subcontinent. There is hardly any effective measure to prevent GBNV in crop plants. In order to develop GBNV infection prevention procedure, we examined the effect of the direct foliar application of double-stranded RNA (dsRNA) derived from the full-length NSs gene (1,320 nucleotides) of GBNV. The bacterially expressed dsRNA to the non-structural (dsNSs) gene of GBNV was purified and delivered to plants as an aqueous suspension containing 0.01% Celite for evaluating its efficacy in preventing GBNV infection in systemic host, Nicotiana benthamiana as well as in local lesion and systemic host, cowpea cv. Pusa Komal (Vigna unguiculata). The dsNSs application and challenge-inoculation were conducted in three different combinations, where plants were challenge-inoculated with GBNV a day after, immediately, and a day before the application of dsNSs. N. benthamiana plants, which were not treated with dsRNA showed severe systemic wilting and death by 9–16 days post-inoculation (dpi). The non-treated cowpea plants exhibited many chlorotic and necrotic lesions on the cotyledonary leaves followed by systemic necrosis and death of the plants by 14–16 dpi. The dsNSs treated plants in all the combinations showed significant reduction of disease severity index in both N. benthamiana and cowpea. The treatment combination where the GBNV inoculation was conducted immediately after the dsNSs treatment was found to be the most effective treatment in preventing symptom expression. The viral RNA analysis by real time PCR also showed 20 and 12.5 fold reduction of GBNV in cowpea and N. benthamiana, respectively. Our results suggest that the foliar application of dsRNA derived from the full-length NSs gene of GBNV through Celite is successful in delivering long dsRNA leading to effective prevention of GBNV infection.

Assessment of the Gastrointestinal Fate of Bacterial Cellulose and Its Toxicological Effects After Repeated-dose Oral Administration

BackgroundBacterial cellulose (BC) is a nanofibrillar polysaccharide produced by certain acetic acid bacteria. BC may be used in food, pharma and many other applications. However, detailed studies of the oral toxicology of BC are limited. Controversial data is published regarding this topic, specially when it comes to answering the question on whether cellulose is absorbed at the intestine.MethodsFollowing the European Food Safety Authority guidelines (EFSA), this work presents the results of a 21-day repeated dose oral toxicity of BC in male and female Wistar Han rats (Wistar rats). In parallel, microcrystalline cellulose Avicel LM310 (commercially available as a food additive) was used. Wistar rats were subjected to daily oral gavage of 0.75 mL of an aqueous suspension 1% (m/v) BC or of its counterpart of plant origin, Avicel LM310. Rats not submitted to gavage were included in the experiment as controls. Clinical observations, such as body weight measurements, food consumption and ophthalmologic evaluations were performed during the assay. After occision, serum chemistry, necropsic examination and histopathological analyses of the liver, kidneys, spleen and small and large intestines were performed. The presence of BC fibers along the gastrointestinal tract was assessed histologically using a Green Fluorescence Protein coupled to a Cellulose Carbohydrate Binding Module (GFP-CBM) from Clostridium cellulolyticum.ResultsNo adverse clinical observations related to BC administration were noticed, nor appreciable differences in the toxicological endpoints evaluated were detected. No evidence of BC persorption was found. Particularly, no BC was detected in the Peyer´s patches or in the mesenteric lymphatic nodules. Moreover, the histopathological analyses revealed that the global architecture and morphology of the organs and tissues was preserved, among the different experimental groups, with no significant pathological changes among them. Regarding serum biochemistry, no significant differences were recorded, for both sexes.ConclusionsThese results demonstrate that BC nanofibers can be considered safe and, as the vegetal cellulose, can be used as a food additive.

Microwave-assisted oxidative coupling of thiols using polystyrene supported bromoderivatives of 2-oxazolidone

Polymer-supported reagents have become popular in synthetic organic chemistry over the past decades. But the kinetics of polymer-supported reactions is slow compared to solution phase synthesis because of the poor diffusion of the reactants through the macromolecular polymer matrix. This difficulty can be reduced to a great extent by performing polymer-supported reactions under microwave (MW) conditions. The present work is focussed on the design and development of an innovative, powerful, MW stable and recyclable polymeric reagent prepared by attaching bromoderivative of 2-oxazolidone into the macromolecular matrix of polystyrene. 3% cross-linked polystyrene was prepared by free radical aqueous suspension polymerization technique using tetra ethylene glycol diacrylate as the cross-linking agent and the resulting beads were functionalized by chloromethylation followed by reaction with 2-oxazolidone. Bromine functionality is introduced into the polymer by treating with bromine in carbon tetrachloride. The synthetic utility of the prepared polymeric reagent was demonstrated by the oxidative coupling of thiols to disulfides under MW irradiation. No over oxidation was observed in this protocol and the utilization of polystyrene support simplifies work up and product isolation. The synthesised polymeric reagent displayed good cyclic stability up to five cycles without any substantial decrease in bromine content and satisfactory storage stability under normal laboratory condition. Moreover this may be the first report that uses MW energy for the oxidation of thiols to disulfides using polymer-supported reagents. [Formula: see text]

Fabrication of YSZ-Carbon Felt Composite Materials by Spark Plasma Sintering Process

Dual-phase membrane composed of oxide ion conductor and electron conductor was fabricated for application to oxygen separation membranes. 8 mol% yttria-stabilized zirconia (8YSZ) and carbon felt were used for the oxide ion conducting phase and the electron conductiing phase, respectively. Carbon felt was impregnated with YSZ aqueous suspension (40 wt%), dried, then sintered by a spark plasma sintering (SPS) process under the applied pressure of 80 MPa at 1200, 1400 and 1600 ° C for 10 min. When sintered at 1600 ° C, the XRD pattern showed small peaks indicating the formation of the zirconium carbide phase, but the microstructure observed by SEM showed that the YSZ was well densified and tightly bonded with carbon felt. This method has been demonstrated to be an effective process for the fabrication of YSZ-Carbon composites with both phases percolation structure.