Papers by Keyword: Synthesis

Abstract: SHM is the advanced way of testing the health of any structure with the help of sensors. Microcontrollers are used to collect the data from the sensors and then the data is evaluated which can be done in real-time which ultimately helps us to know whether the structure is safe or not. Other than these conventional types there are other sensors such as mechanoluminescence (ML) sensors that do not require any external power. ML is a form of luminescence that is produced by mechanical forces such as fracture, friction, stress, crack, tension and compression. This aids us in directly visualizing stress and cracks on the structure’s surface. This review paper aims on discussing some common and widely used ML material along with some of the synthesis and loading techniques.

Abstract: The influence of microstructure on the resulting physico-mechanical and refractory properties of refractory forsterite–spinel ceramics was investigated in this paper. The raw materials were milled, mixed into four different raw material mixtures and sintered for two hours at 1550°C. The microstructure of the samples was examined by scanning electron microscopy and X-ray diffraction analysis was used to determine the mineralogical composition of the sintered samples. Physico-mechanical properties such as porosity, water absorption, bulk density, and modulus of rupture were also determined. Thermomechanical characteristics were assessed by the determination of refractoriness, refractoriness under load, thermal shock resistance and corrosion resistance to various metals. The results showed that a higher amount of spinel leads to improved microstructure, thermal shock resistance and that all mixtures have high corrosion resistance to all tested materials.

Abstract: Drug resistant microbial strains are becoming continuous dilemma for researchers; hence, some alternates are required to combat this issue. In this way, nanotechnology is fascinating researchers to put forward a step in order to synthesize metals nanoparticles via adopting an ecofriendly, facile, and quick approach using medicinal plants. By means of aqueous extract of Polyalthia longifolia (AEPl), gold nanoparticles (AuPl) were synthesized for the mechanism study of synthesis and antibacterial bahavior. The reddish colored solution was an indicative clue of synthesis showing surface plasmon band at 540nm using UV/Visble spectroscopy. Various functional groups in the extract were identified which participated in the reduction of metal ions to metallic form as indicated from the Fourier Transform Infrared (FTIR) spectra of AuPl. Moving ahead, the synthesized AuPl were characterized through Transmission Electron Microscopy (TEM) showed spherical shape with more or less 50nm size. Besides, Scanning Electron Microscopy (SEM) study revealed some aggregates formation. Further, structural characterization via X-Rays Diffractometry (XRD) displayed crystallline nature of these nanoparticles. Finally, Energy Dispersive X-rays (EDX) analysis described their metallic form. The antibacterial activity at increased concentration when measured; AuPl showed 15 and 18mm bacterial growth inhibition zones against Escherichia coli and Bacillus subtilis at 100μg/mL concentration respectively. In addition, significant least minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of AuPl against these microbes were also observed. In the light of the above knowledge, it is inferred that the biogenic AuPl exhibit strong antibacterial potential enabling them to be a good substitute of antibiotics.

Abstract: MXene is a recently emerged two dimensional (2D) layered materials, a novel series of transition metal carbides, nitrides and carbonitrides were established by a group of scientists from Drexel University in 2011. Multi-layered MXene nanomaterials have been synthesized using different wet chemistry etching approaches. To date, around twenty different types of MXenes are synthesized using different wet chemistry etching techniques. To ensure reproducibility of the MXene, advanced characterizations in terms of morphology, structure as well as elemental compositions of the MXene flakes are conducted. MXenes nanosheets possess a significant thermo-electrical conductivity, reasonable band gap and high intrinsic carrier mobilities. The family materials of the MXenes have high potential for making energy storage devices such as batteries and supercapacitors as well as several many other implications such as electromagnetic interference shielding and capacitive desalination. MXenes are the potential candidates for hydrogen storage due to the interactive nature of hydrogen and these layered-structure materials. MXenes in biomedical applications were proven as valuable materials due to the tunable physiochemical properties into new distinct structures which is difficult to be manipulated in bulk materials. Besides, MXenes possess suitability of functionalization for tuning the various required properties for the specific properties. The many potential properties of MXene have disclosed new possibility to address the current need of higher efficiency materials for different applications.

Abstract: Li ion battery or LIB is an energy storage device that provides and store electrical energy and chemical energy, respectively. LIBs have been widely developed in the energy sector owing to their considerable high energy density, high capacity, and long-life cycle. In this study, the LiFePO₄/C cathode was synthesized from various precursors FeC₂O₄, FePO₄, Fe₃(PO₄)₂, Fe₂O₃ obtained via co-precipitation method, and continued with solid-state. The effects of precursors were studied in this study. The precursor and the resulting product were analyzed using XRD, FTIR, SEM, and EDX, while the electrochemical performance was tested using charge-discharge, cycle stability and rate capability. All precursors were successfully synthesized as evidenced by XRD, FTIR, SEM, and EDX characterization tests. Based on electrochemical performance test, the highest capacity that can be achieved is 109 mAh/g obtained from LFP with FeC₂O₄ precursor, with a reduction in capacity of 54.7% after 50 cycles.

Abstract: Refrigerants are commonly used as heat transfer fluid in refrigeration, heat pumps, and air conditioning systems. Nanorefrigerants are a special kind of nanofluid synthesized by dispersing nanoparticles into refrigerants or lubricant oil to improve its thermophysical and heat transfer characteristics. The optimization of the thermophysical properties of nanorefrigerant strongly depends on the successful synthesis procedures used for producing a stable suspension of nanoparticles in the refrigerants. In this study, a review was carried out to understand the synthesis of nanorefrigerant and the effect of nanoparticle size, type and concentration, temperature, base fluid type on the thermophysical properties of the nanorefrigerant. The effect of nanorefrigerant on the pressure drop and boiling heat transfer within the vapour compression refrigeration system (VCRS) was reviewed. From the review, the thermophysical properties of the nanorefrigerants affect the pressure drop and heat transfer characteristics of the vapour compression refrigeration system.

Abstract: In industry, synthetic zeolites are commonly used as ion-exchange materials, catalyst supports, and adsorbents. As a result, a more energy-efficient alternative for its synthesis from low-cost and accessible raw materials is needed. This study, presents the possibility of using class F South African coal fly ash (SACFA) from Lethaba thermal-power station as a precursor to produce zeolites via a microwave (MW) assisted synthesis route. The mineral content of synthetic materials was determined using X-ray florescence (XRF). Morphology was determined using a Scanning electron microscopy (SEM), elemental composition by energy dispersive spectrometer (EDS). X-ray diffractometry (XRD) was used to get structural characterization. Microwave (MW) irradiation time and intensity enhance the crystallization of the zeolite phase as a result of sufficient energy required to enable the solubility of alumina and silica from coal fly ash. The use of MW irradiation provides a green alternative to zeolite synthesis from fly ash (FA) than traditional thermal and fusion techniques, which uses a great deal of energy consumption and a longer reaction time.

Abstract: Three polyethylene glycol propargyl ethers (PGPEs), namely 4,7,10-trioxatrideca-1,12-diyne (TOTDY), 4,7,10,13-tetraoxahexadeca-1,15-diyne (TOHDY) and 4,7,10,13,16-pentaoxanonadeca-1,18-diyne (TONDY) were designed and successfully synthesized as curing agents for glycidyl azide polymer (GAP). Their structures were characterized by FT-IR, 1H NMR, 13C NMR and elemental analysis, and their glass transition temperatures (Tg) were measured by DSC. The films of GAP cured by the title compounds were prepared via 1,3 dipolar cycloaddition, and then the influences of PGPEs on the Tg, decomposition temperature (Td) and mechanical properties of the films were studied accordingly. The results showed that the Tg of GAP cured by TOTDY and TOHDY were-38.1 oC and-38.2 oC, respectively. The Td of GAP cured by PGPEs was in the range of 235.5 oC - 241.0 oC. The results of tensile tests showed that the maximum stress of GAP films cured with PGPEs were in the range of 0.11 MPa to 0.52 MPa at elongation from 29% to 48%. These results indicated that PGPEs would have potential application in GAP based high energy solid propellant formulations.

Abstract: Modelling and identification of the synthesis of SDRL rubber in the presence of toluene and modifier was carried out. The mechanism of the polymerization of butadiene on the lithium catalytic system. One of the most characteristic differences between the processes of ionic, in particular, anionic, polymerization and radical polymerization is that even when using initiators that seem to be individual, several forms of active centres, that differ in their reactivity, can simultaneously be present in systems.

Abstract: The ethyl glycol vinyl ether polyoxyethylene ether (EPEG) is a new type of macromonomer to synthesize polycarboxylate superplasticizer (PCE), which has higher reactivity due to the unsaturated double bond and easily to polymerization. The EPEG slump retaining typed PCE can be synthesized by free radical polymerization though EPEG, acrylic acid and hydroxyethyl acrylate (HEA). The HEA had the greatest influence on slump retaining performance. High polymerization conversion rate of EPEG typed PCE was beneficial to improve the concrete performance.