Synthesis and Characterization of Pentaeritritol Tetranitrate (PETN)

Pentaerythritol tetranitrate is considered a high explosive that has been widely studied for its chemical and mechanical properties due to its nitrate ester group structure. Its applicability is intended from military purposes to medicine and pharmacy. It is often a substitute for nitroglycerin and can be incorporated into polymeric matrices that enhance its properties and make it safer to handle. In this work a synthesis of direct form elaborated according to the reference material was presented, by the discontinuous nitration process, conducted in several steps starting from Pentaerythritol (PE) with fuming nitric acid, having a very significant and expected yield according to data referenced in previous studies. Fourier Transform Infrared Spectroscopy (FTIR-ATR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analyzes confirm the chemical structure of the substance obtained and the mass variation as a function of temperature, and typical information which can be derived from measurements such as characteristic temperatures (melting, crystallization, reactions, glass transition) for characterization of high energy materials. The explosive obtained by the new route proves to be effective and high yield.

Exploration of the Sparck Plasma Sinter Technique for the Manufacture of Implants for Orthopedic Applications: Development of A High-Performance Nbti-Swcnts Nanocomposite Welded Tv6a Alloy and Densification of Preforms

Nanocomposite Ti 50 wt% Nb with and without reinforcement of carbon nanotubes were successfully fabricated by ball milling of Ti, Nb and SWCNTs (single walled carbon nanotubes) nanopowder mixture folloyed by field actived spark plasma sintering process (FASPS) for biomedical application, superconductivity and magnetism in the ITER Project. The use of brittle Ti powder, instead of ductile elemental powder, led to significant increment in the yield of mechanically alloyed powder. The powder consisted of homogeneously distributed nano-sized Ti/Nb particles together with micronsized pure Nb particles. Sintering of the powders under low temperature and pressure conditions (1273 K, 1473 K and P=50 Mpa) resulted in the fine-grained heterogeneous microstructure consisting of α and β phases. On the other hand, sintering at higher temperatures (1473 K) resulted in a relatively coarse-grained chemically homogeneous microstructure with almost complete phase. Coarse-grained homogeneous β NbTi alloy exhibited higher average hardness as compared to that of heterogeneous fine grained microstructures. An attempt has been made to illustrate the correlation between the microstructural characteristics and mechanical properties of the sintered Ti50Nb compacts. To studies and to develop the influence of SWCNTs on the behavior of the nanocomposite TiNb/SWCNTs and the welding joint interface between TA6V and nanocomposite by sparck plasma sintering. At last, the continuation of the work has been discussed and prepared, planning dynamic flexion tests to measure the NbTi, NbTi/CNTs, NbTi/SWCNTs,/TA6V fatigue limit and developing a computer processing chain in order to customize prostheses respecting patients’ morphology. The fluid ethanchied lubrification of the prosthesis articulation is currently also in study and preparation. Then, a change of scale made possible by the use of an industrial size SPS machine led to the realization of types of blade perform according to patent morphology. These results led to the filing of a patent.

Moringa Oleifera Seed Oil as Green Corrosion Inhibitor for Ductile Cast Iron in Cassava Fluid

Cassava fluid is acidic and corrodes the ductile cast iron parts from which many machineries used in processing cassava, a staple source of carbohydrates in most West African countries are made. The corrosion behavior of ductile cast iron cassava fluid with Moringa Oleifera seed oil as inhibitor was studied using 0, 0.2, 0.4, 0.6, and 0.8 %v/v concentrations and at two different temperatures of 40oC and 60oC by potentiodynamic polarization (Tafel) technique. Some thermodynamic, Corrosion inhibition and adsorption studies were also addressed. Moringa Oleifera seed oil extract was found to successfully inhibit the corrosion of cast iron in cassava fluid. Moringa Oleifera acted as a mixed type inhibitor. The corrosion inhibition efficiency was found to increase with increase in concentration of the extract but decrease with rise in temperature. The maximum inhibition efficiency of the extract on ductile cast iron corrosion was noted to be about 73%. Adsorption studies showed that Langmuir isotherm describes the manner in which the inhibitor was adsorbed on the metal surface. The adsorption process was found to be spontaneous as all the free energy of adsorption values calculated were negative and ranged from -3.43 kJ/mol to -1.34 kJ/mol, signifying a spontaneous physical adsorption on metal surface. The stereo-micrograph images of the metal surface after immersion in corrosive medium confirmed the protection offered by the Moringa Oleifera extract on the surface of the metal. It was further shown that the corrosion rate was influenced by the combined interactions of temperature of operation and concentration of the inhibitor.

Diffusion of Innovative Water Atomization Technology to Conserve Water in Water Stress Countries

Clean water is a challenge in water stress semi-arid country like Botswana. All the perennial rivers are shared with river basins of neighbouring countries. Some of the ground water in aquifers are of fossil nature and remain without any recharge. The low rainfall and the increasing temperature increase further the scarcity of water. With the Adaptation at Scale in Semi-Arid Regions (ASSAR), the impact of climate change due to Global warming for Botswana, it is estimated that the Limpopo Catchment (runoff) would decrease 26%, 36%, 46% and 56% under the global warming 1.5° C, 2° C, 2.5° C, and 3° C respectively. Hence water management is imperative in Botswana In managing water, demand management with price and non-price strategies, is the most abundantly used approach. In this respect, a recently emerged strategy is the application of water atomization technology. This research investigates the effectiveness of using water atomization technology at Botho University, as a large size consumer in Botswana and envisage further to scale up to a macro level in Botswana. At Botho University, having studied this as a case study project, it was found that the application of water atomization technology at micro level enables us to save 75% of water that was previously consumed. The installation of technology is a simple process and the payback period is shorter. Further, it was found that the projection for the application of the technology at macro level reflects that there would be a saving of water by 36 million kilolitres. Hence, it was recommended to have a marketing strategy based on principles of persuasion for diffusion of innovative technology to attract adopters, within a budgeted period of ten years. These findings and recommendations are significant not only for micro level application but also macro level application in the country for fulfilling the pledge taken by the country and corporate citizens with SDG 06: Clean Water for all and Sanitation & SDG 12: Responsible Consumption of 2030 Agenda for 17 Sustainable Development Goals(SDGs). However, the study is subject to the limitation that assessing water savings expected from the water technology among various types of customers at macro level is dependent on high resolution water consumption data which is not publicly available.

Green ultrasonic synthesis, Characterization and Antibacterial activity of Silver and Gold Nanoparticles mediated by Ganoderma lucidum extract

Metal nanoparticles possess an extensive scientific and technological significance due to their unique physiochemical properties and their potential applications in different fields like medicine. Silver and gold nanoparticles have shown to have antibacterial and cytotoxic activities. Conventional methods used in the synthesis of the metal nanoparticles involve use of toxic chemicals making them unsuitable for use in medical field. In our continued effort to explore for simple and eco-friendly methods to synthesize the metal nanoparticles, we here describe synthesis and characterization of gold and silver nanoparticles using Gonaderma lucidum, wild non-edible medicinal mushroom. G. lucidum mushroom contain bioactive compounds which can be involved in the reduction, capping and stabilization of the nanoparticles. Antibacterial activity analysis was done on E. coli and S. aureus. The synthesis was done on ultrasonic bath. Characterization of the metal nanoparticles was done by UV-VIS., High Resolution Transmission Electron Microscope (HRTEM) and FTIR. HRTEM analysis showed that both silver and gold nanoparticles were spherical in shape with an average size of 15.82±3.69 nm for silver and 24.73±5.124nm for gold nanoparticles (AuNPs). FTIR analysis showed OH and -C=C- stretching vibrations, an indication of presence of functional groups of biomolecules capping both gold and silver nanoparticles. AgNPs showed inhibition zones of 15.5±0.09mm and 13.3±0.14mm while AuNPs had inhibition zones of 14.510±0.35 and 13.3±0.50mm on E. coli and S. aureus respectively. The findings indicate the potential use of AgNPs and AuNPs in development of drugs in management of pathogenic bacteria.

Comparative Study on the Corrosion Behaviour of welded and un-welded Mild Steel in Agitated Media of Distilled Water 0.5mol, 0.3mol of Sodium Sulphate (Na2SO4) Solution

The research work was based on the comparative study of the corrosion bebaviour of the mild steel using agitated distilled water with 0.5 mol and 0.3 mol of Na2SO4 solution. The materials used for the research work are welded and un-welded mild steel. The mild steel materials were obtained at the Foundry shop of the Ajaokuta Steel Company Limited. The mild steel materials were analyzed using the SPECTRO Analytical Instruments at the Foundry shop of the company. These experiments were performed using 0.5mol and 0.3mol of Na2SO4 in different agitated media of distilled water .The samples used for general corrosion studies were 10mm and 4mm mild steel thickness. These materials were cut into specimen sizes to 2cm by 2cm). Twenty -eight (28) specimens each were prepared for the 10mm and 4mm mild steel materials the samples were ground and polished on the emery papers which removed rust particles on the test materials. The specimens were exposed for days for over fifty –four (54) days, with an interval of 3days. It was observed that welded materials have higher corrosion rate than the un-welded materials when subjected to experimental conditions. The corrosion rates values were used to plot graphs against time of exposure.

The Investigation Thermal Efficiency of High Performance Fiber Reinforced composites with additive Multi-Wall Carbon Nanotubes

Every year thousands of traffic accidents occur due to icing of roads which challenge lives and property. In this study the suitability of steel fibers and multi wall carbon nano tube (MWCNT) for electrical (Joule) heating was determined by cluster heating test which is novel for the literature. In this study, the bearing elements of the buildings and roads are intended to be a heater. Experiments were tested for a total of four weeks, once every week. During the tests, the top surface temperature, the voltage supplied and the current were recorded. The temperature increase and temperature increase rate were determined. Mortar having MWCNT ratio showed a superior heating performance for 4 weeks. In this study, the bearing elements of the buildings and roads are intended to be a heater. The thermal efficiency of the high performance fiber reinforced composites were investigated.

On Similarity of Seismo Magentic Field and Pressure Head Fractal Dimension for Characterizing Shajara Reservoirs of the Permo-Carboniferous Shajara Formation, Saudi Arabia

The quality and assessment of a reservoir can be documented in details by the application of seismo magnetic field. This research aims to calculate fractal dimension from the relationship among seismo magnetic field, maximum seismo magnetic field and wetting phase saturation and to approve it by the fractal dimension derived from the relationship among inverse pressure head * pressure head and wetting phase saturation. Two equations for calculating the fractal dimensions have been employed. The first one describes the functional relationship between wetting phase saturation, seismo magnetic field, maximum seismo magnetic field and fractal dimension. The second equation implies to the wetting phase saturation as a function of pressure head and the fractal dimension. Two procedures for obtaining the fractal dimension have been utilized. The first procedure was done by plotting the logarithm of the ratio between seismo magnetic field and maximum seismo magnetic field versus logarithm wetting phase saturation. The slope of the first procedure = 3- Df (fractal dimension). The second procedure for obtaining the fractal dimension was determined by plotting the logarithm (inverse of pressure head and pressure head) versus the logarithm of wetting phase saturation. The slope of the second procedure = Df -3. On the basis of the obtained results of the fabricated stratigraphic column and the attained values of the fractal dimension, the sandstones of the Shajara reservoirs of the Shajara Formation were divided here into three units.

Structural, Optical and Electrical Properties of Electron Beam Evaporated Tioxny Films as Selective Solar Absorber Coatings

Titanium oxinitride (TiOx Ny ) solar absorber coatings were deposited at different oxygen partial pressures onto Cu, Si and glass substrates using electron beam evaporation technique. XRD diffraction patterns evidenced (111), (200) and (220) orientation of TiNx phase. The preferred orientation of the films changed with oxygen partial pressure. XPS revealed the intensity of both Ti 2P3/2 and Ti 2P1/2 increases as a function of oxygen flow, and also shifted towards higher binding energy, indicating more oxidized state of Ti species than that of TiO2 due to incorporation of nitrogen atoms. Formation of uniformly distributed spherical like particles and an increase in surface roughness of the TiOx Ny films were observed as a function of oxygen partial pressure as depicted from SEM and AFM, respectively. Ellipsometric and resistivity measurements showed a shift from metallic to semiconductor behaviour of the TiOx Ny films as oxygen flow changed. A solar absorptance value of 0.94 in the solar spectrum region and a low thermal emittance value of 0.05 were achieved for the TiOx Ny solar absorber coatings prepared at the oxygen partial pressure of 7.5x10-5 Torr due to both interference and intrinsic absorption. This study confirmed that a single layer of TiOx Ny film can be a good candidate as selective solar absorber.

What are Reversed Spheres?

In our universe we have only two elements: mass which is a sphere and radiation which is a reversed sphere. A sphere has the maximum volume with minimum exterior surface and a reversed sphere has minimum volume while having maximum exterior surface. A sphere has a centre and a surface at a fix distance in all directions while a reversed sphere has the centre everywhere in all directions and the surface covering all radiuses heading towards its middle point. Interaction between mass creates events and exchange of energy, while interaction between radiations doesn’t. Interaction between mass and radiation is rare in universe. Any sphere of mass has around it a reversed sphere of radiation (gravity) which prevents it from exploding back. When mass and radiation interact, the reversed sphere surrounding mass disturbs the trajectory of pure radiation. The first one has a constant force due to surface of mass in the middle, while the second one has the tendency to expand as it has nothing in the middle. It is possible to transfer mass (spherical radiation) into radiation (linear radiation) and radiation into mass because of the formula E=mc2, but the conditions form initial big bang are needed in order to create/destroy gravity.