18 research outputs found

    Technologies for Deviation of Asteroids and Cleaning of Earth Orbit by Space Debris

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    The present chapter presents the advanced design and technology of special equipment (SECSL) which uses concentrated solar light for deviation of asteroids and cleaning the space of debris. The elliptical orbit of any cosmic body as presented in Einstein’s general theory of relativity is rotating around the ellipse center. The trajectory of a cosmic body is permanently affected by the gravity of other moving cosmic bodies. In the case of asteroids (relatively small masses), orbit changes can lead to a collision with the Earth. At this very moment, our civilization has no efficient and reliable mean to destroy or divert a cosmic body heading toward the Earth. This new idea represents a “light canon” which uses concentrated solar light for deviation or vaporization of dangerous asteroids. The equipment is composed out of two parabolic mirrors (one large and one small) with the same focal point and coincident axes. The mirrors reflect the sunlight between them hence the term “concentrated solar light.” Next, a similar idea to the SECSL equipment is presented but applied to space debris caused mostly by humans and a new way of disintegrating satellites, spent rocket boosters, thrust chambers, etc. in the Earth’s atmosphere during reentry

    Sonic Boom Mitigation through Shock Wave Dispersion

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    Lately, the interest for passenger space planes, supersonic passenger aircraft, and supersonic business jets has greatly increased. In order to mitigate the sonic boom effects at ground level, some aerospace companies proposed airplanes that have a very small transversal fuselage section or that have a curved (“shaped”) fuselage. Obviously, shaping the fuselage leads to the increase of dynamic drag and manufacturing cost. Reducing the fuselage transverse section leads to reducing the useful volume inside fuselage and increases the landing distance of aircraft. The solution presented in this chapter shows that it is theoretically and technologically possible as the shock wave to be dispersed through mechanical or electrical means. The shock wave is in fact a stationary effect generated by the move of aircraft with constant speed relatively to surrounding air. If this feature is in a way or another canceled, the shock wave is dispersing. Due to dispersion of the shock wave the ‘N’ wave at the ground is tens of times larger and the sonic boom is correspondingly lower. The shock wave dispersion system of the future could be mechanical or electrical is activated only when the supersonic aircraft/space plane is flying horizontally over community

    Experimental Investigations on the Possibility to Apply the Corrugated Sheet Metal Used in the Past with Junkers Aircraft to Reduce Noise for Future European Aircraft. Other Noise Reduction Experiments for Future European Aircraft

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    This paper shows that corrugated skin used in the past with Junkers aircraft to increase the fuselage and wing rigidity can lead to noise reduction for future European aircraft. If the pressure side of wing which is placed above the engine is corrugated, the jet noise reflected by wing will be scattered. This way, the diffuse acoustic field has a lower intensity at ground level and correspondingly, a lower impact on community. Similarly, it is shown that if the underside of fuselage is corrugated, the noise emitted by the nose landing-gear and main landing-gear is also scattered. The existence of this effect is demonstrated by some recent measurements done inside auto-tunnels covered inside with corrugated sheet metal which indicated a reduction of maximum noise level by up to 30%. Some experiments done by the authors at low scale on an Airbus A380 wing model (scale 1:375) showed that the jet-noise reflected by the corrugated skin of wing is reduced by 4 dB in the near field. Reintroducing corrugated skin in the manufacturing process of modern aircraft is beneficial because, on the one hand, it reduces the jet and the landing-gear noise discomfort and, on the other hand, it permits manufacturing stronger frames for passenger aircraft/airliners

    Polymer Membranes as Innovative Means of Quality Restoring for Wastewater Bearing Heavy Metals

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    The problem that has aroused the interest of this review refers to the harmful effect of heavy metals on water sources due to industrial development. In this respect, the review is aimed at achieving a literature survey on the outstanding results and advancements in membranes and membrane technologies for the advanced treatment of heavy metal-loaded wastewaters. Particular attention is given to synthetic polymer membranes, for which the proper choice of precursor material can provide cost benefits while ensuring good decontamination activity. Furthermore, it was also found that better removal efficiencies of heavy metals are achieved by combining the membrane properties with the adsorption properties of inorganic powders. The membrane processes of interest from the perspective of industrial applications are also discussed. A noteworthy conclusion is the fact that the main differences between membranes, which refer mainly to the definition and density of the pore structure, are the prime factors that affect the separation process of heavy metals. Literature studies reveal that applying UF/MF approaches prior to RO leads to a better purification performance

    Food Intake of Macro and Trace Elements from Different Fresh Vegetables Taken from Timisoara Market, Romania—Chemometric Analysis of the Results

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    Vegetable consumption is recommended and encouraged by all nutritionists and doctors across the planet. However, in addition to minerals which are beneficial to the body, certain minerals with a negative influence on human health can sneak in. It is very important that in the case of some minerals their content in vegetables is known, so that the recommended limits are not exceeded. The purpose of this study was to evaluate the macro elements (Na, K, Ca, Mg) and trace elements (Cu, Mn, Fe, Cd, Pb, Zn, Co) in 24 samples of vegetables from four botanical families (Solanaceae, Brassicaceae, Apiaceae and Amaryllidaceae), purchased from the market in Timișoara, Romania, both imported products as well as local products. The atomic-absorption-spectrometry technique (FAAS) was used to evaluate the macro elements and trace elements. The values obtained for the macro elements and trace elements were used as input data for the analysis of multivariate data, the principal component analysis (PCA) in which the vegetable samples were grouped according to their contribution of certain mineral elements, as well as according to some of the botanical families to which they belong. At the same time, based on the values obtained for trace elements, an assessment of the risk to human health in terms of consumption of the vegetables studied was carried out. The risk assessment for human health was determined on the basis of the estimated daily dose (EDI), the values of the target hazard coefficient (THQ), the values of the total target hazard coefficient (TTHQ) and the carcinogenic risk (CR). Following the determination of THQ, the values obtained followed the order THQWith > THQCd > THQPb > THQCo > THQMn > THQZn > THQFe. The results on the content of macro elements and trace elements, as well as the assessment of the risk to human health when consuming the assessed vegetables, were within the limits of European Union (EU) and World Health Organization and Food and Agriculture Organization (WHO/FAO)legislation

    Shaping in the Third Direction; Synthesis of Patterned Colloidal Crystals by Polyester Fabric-Guided Self-Assembly

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    A polyester fabric with rectangular openings was used as a sacrificial template for the guiding of a sub-micron sphere (polystyrene (PS) and silica) aqueous colloid self-assembly process during evaporation as a patterned colloidal crystal (PCC). This simple process is also a robust one, being less sensitive to external parameters (ambient pressure, temperature, humidity, vibrations). The most interesting feature of the concave-shape-pattern unit cell (350 μm × 400 μm × 3 μm) of this crystal is the presence of triangular prisms at its border, each prism having a one-dimensional sphere array at its top edge. The high-quality ordered single layer found inside of each unit cell presents the super-prism effect and left-handed behavior. Wider yet elongated deposits with ordered walls and disordered top surfaces were formed under the fabric knots. Rectangular patterning was obtained even for 20 μm PS spheres. Polyester fabrics with other opening geometries and sizes (~300–1000 μm) or with higher fiber elasticity also allowed the formation of similar PCCs, some having curved prismatic walls. A higher colloid concentration (10–20%) induces the formation of thicker walls with fiber-negative replica morphology. Additionally, thick-wall PCCs (~100 μm) with semi-cylindrical morphology were obtained using SiO2 sub-microspheres and a wavy fabric. The colloidal pattern was used as a lithographic mask for natural lithography and as a template for the synthesis of triangular-prism-shaped inverted opals

    Shaping in the Third Direction; Fabrication of Hemispherical Micro-Concavity Array by Using Large Size Polystyrene Spheres as Template for Direct Self-Assembly of Small Size Silica Spheres

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    Silica and polystyrene spheres with a small size ratio (r = 0.005) form by sequential hanging drop self-assembly, a binary colloidal crystal through which calcination transforms in a silica-ordered concavity array. These arrays are capable of light Bragg diffraction and shape dependent optical phenomena, and they can be transformed into inverse-opal structures. Hierarchical 2D and 3D super-structures with ordered concavities as structural units were fabricated in this study

    Hybrid Cryogels with Advanced Adsorbent Properties for Penicillin

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    In recent years, natural polymers (chitosan and biocellulose) have sparked interest, especially when it comes to medical uses (wound healing, excipients for drug administration), due to their great biocompatibility and low toxicity [...

    A Top-Down Procedure for Synthesizing Calcium Carbonate-Enriched Chitosan from Shrimp Shell Wastes

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    Chitosan is used in medicine, pharmaceuticals, cosmetics, agriculture, water treatment, and food due to its superior biocompatibility and biodegradability. Nevertheless, the complex and relatively expensive extraction costs hamper its exploitation and, implicitly, the recycling of marine waste, the most abundant source of chitosan. In the spirit of developing environmental-friendly and cost-effective procedures, the present study describes one method worth consideration to deliver calcium-carbonate-enriched chitosan from shrimp shell waste, which proposes to maintain the native minerals in the structure of chitin in order to improve the thermal stability and processability of chitosan. Therefore, a synthesis protocol was developed starting from an optimized deacetylation procedure using commercial chitin. The ultimate chitosan product from shrimp shells, containing native calcium carbonate, was further compared to commercial chitosan and chitosan synthesized from commercial chitin. Finally, the collected data during the study pointed out that the prospected method succeeded in delivering calcium-carbonate-enriched chitosan with high deacetylation degree (approximately 75%), low molecular weight (Mn ≈ 10.000 g/ mol), a crystallinity above 59 calculated in the (020) plane, high thermal stability (maximum decomposition temperature over 300 °C), and constant viscosity on a wide range of share rates (quasi-Newtonian behavior), becoming a viable candidate for future chitosan-based materials that can expand the application horizon
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