Assessing the Effect of PVP of Various Molecular Weight (MW) in PES-Ag Membranes: Antimicrobial Study Using E.Coli

New polymeric silver (Ag) composites were prepared using polyethersulfone (PES) as polymer material, N-Methyl-2-pyrrolidone (NMP) as solvent and polyvinylpyrollidone (PVP) of various molecular weight (MW) as organic fillers. Silver nitrate (AgNO3) was added by various loading in order to impart an antibacterial property to the composites. The miscibility of PES/Ag/fillers composites were characterized using TGA and any changes in chemical bonding were characterized using ATR-FTIR techniques. The XPS results showed high intensity in Eb(Ag3d) range of 378.1-378.5 and 372.2-372.5 for the highest Ag loading with PVP with the highest MW. This phenomenon had altered the hydrophilicity property of composites. In this study, composites have undergone a bacteria rejection test from E.coli suspension and a domestic waste sample. Composites with highest loading of silver and highest MW of PVP (PES-Ag2P360) was observed for significantly high bacteria rejection, log reduction value (LRV~3). Therefore, PES-silver nanocomposites is a potential membrane for bacteria removal, disinfection and maybe effective for overcoming biofouling problems

Studying the physicochemical properties and isolation of unsaturated fatty acids from edible oils by GC-MS and argentated silica gel chromatography

The core objective of this study was to investigate the physicochemical characteristics and fatty acid composition of the oils of sunflower, olive, virgin coconut and ginger oils, as well as the separation of their unsaturated fatty acids. The data indicated a significant variation in physicochemical properties (acid, saponification, ester, and iodine values) among oils. Transesterification process was carried out at a molar ratio of 1:7:0.1 of oil: methanol: KOH. Fatty acid methyl esters of oils were analyzed by infrared (IR) and gas chromatography–mass (GC-MS) spectrometry. Twelve fatty acids were identified, where the major fatty acid of olive oil was found to be oleic acid (89%), whereas those of sunflower and ginger oils were linoleic acid (80.9 %) and (79.3 %), respectively. Sunflower and olive oils were fractionated by 25% silver nitrate-impregnated silica gel column chromatography. By this method, linoleic acid methyl ester from sunflower and oleic acid methyl ester from olive oil were isolated with high purity percentages and yields. This study is significant for the development of food and pharmaceutical products

Effect of co-doped SnO2 nanoparticles on the optical properties of Cu-doped lithium potassium borate glass

The co-doped SnO2 nanoparticles of lithium potassium borate doped with Cu glass were prepared using the chemical quenching technique. The X-ray diffraction analysis revealed the amorphous nature of the sample. The morphology was determined using high resolution scanning electron microscopy (FE-SEM). The photoluminescence properties and energy band gaps of the glass were investigated. The changes in the energy band gap were due to the concentration of SnO2 nanoparticles and copper ions. An enhancement of almost three times was shown when SnO2 nanoparticles were added as co-dopants to 0.1 mol% of Cu and the peak shapes shifted from blue luminescence to blue and green luminescence

Predictive model of 2-cyclohexylthiophene for corrosion inhibition in mild steel using computational method

Corrosion inhibition activity of 2-cyclohexylthiophene (2CHT) for mild steel in acidic media was predicted using QSAR tool. The model used two descriptors namely; Moran autocorrelation of lag4 weighted by mass (MATS4M) which explained the linearity and branching of the compounds and largest eigen values n3 of burden matrix weighted by mass (SPMAX3-Bh(m)) describes the nature and size of the neighboring atom. The modeling results revealed the potential of the compounds as a good corrosion inhibitor with percentage inhibition efficiency (%IE) of 76.5%. Quantum chemical calculation using DFT with 6-311G++(d,p) basis was used to evaluate the performance of the predicted compound as corrosion inhibitor by quantum chemical parameters such as EHUMO, ELUMO, Energy gap (Egap), hardness (?), softness (S), dipole moment (µ), electronegativity (X), electron affinity (A), ionization energy (I) and total energy (TE). The results obtained from quantum chemical parameters were found to be consistent with predicted result

Effects of copper, nickel, and its alloy as catalysts for graphene growth via chemical vapor deposition method: a review

Enormous characteristics exhibited by two-dimensional carbon-based nanomaterial, graphene attract current researchers in integrating this advanced material into the development of next-generation electronic, optoelectronic, photonic, and photovoltaic devices. The ultimate aim was to synthesis a single layer of graphene with large-size domain with less defect formation. The solid state of the graphene promises ultra-high performance in the devices due to ultra-high electron mobility. Within a decade, previous researchers have narrowed down their studies by applying different types of metal species as catalyst substrate in chemical vapor deposition method. The crucial part was to determine the characteristics of carbon precipitation and diffusion onto the metal surfaces. Each metal-based catalyst and its alloy revealed different behavior according to its carbon solubility and intrinsic properties. Until now, copper, nickel, and its alloy combination provide tremendous finding in the synthetization of graphene. Currently, researchers are still exploring the ideal parameters related to feeding gases, growth temperatures, and working pressures which are essential to each catalyst metals characteristic such as copper, nickel, and its alloy

Morphological study of synthesized RGO/ Pt nanocomposites via facile chemical reduction method

Reduced graphene oxide nanosheet (RGO)/Pt nanocomposite have been successfully prepared through a facile chemical reduction method. The reduction of Pt precursor was carried out using sodium borohydride as the efficient chemical reductant. The morphology of RGO/Pt nanocomposite was investigated using high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). HRTEM analysis showed that platinum nanoparticles were homogenously distributed onto the surface of RGO. The electrochemical study proved that Pt nanoparticles were successfully incorporated onto RGO. Therefore, it can be concluded that the proposed method could provide well-dispersed of Pt nanoparticles onto RGO to form RGO/ Pt nanocomposite

Theoretical and experimental studies of corrosion inhibition of thiohene-2-ethylamine on mild steel in acid media

Corrosion inhibition of mild steel in 0.5M H2SO4 at 30°C with thiophene-2- ethylamine (TEA) as inhibitor has been assess by quantitative structure activity relation (QSAR) model and quantum chemical calculations. The results were evaluated using weight loss and electrochemical methods such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed good performance of TEA in corrosion protection which behaves as mixed inhibitor from PDP. The micrograph from FESEM and EDX dot mapping showed that the inhibitor adsorbed onto the metal surface with different distribution for S, C and N atoms which indicate less damage on the metal surface in the presence of TEA

Synthesis of graphene oxide nanosheets via modified hummers’ method and its physicochemical properties

The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR. XRD pattern of GO showed 2? of 12.0° with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with p-p* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application

Optical properties of sensitized tin dioxide thin film prepared by using sol-gel spin coating method

Undoped tin dioxide (SnO2)thin films were prepared by sol-gel spin coating process using an alcoholic solution of tin chloride dihydrate (SnCl2.2H2O) as the precursor. The tin dioxide doped terbium (Tb3+) and erbium (Er3+) ion thin films were also prepared using sol gel method in order to form SnO2:Tb3+ and SnO2:Er3+ thin films. The concentration of Tb3+ and Er3+ is 5% in relation with the tin content in the sol. The doped and undoped SnO2 films were sensitized with eosin Y. The diameter of particles in the SnO2 film ranges from 20 to 46 nm with spherical morphology. The particle size of SnO2 doped Tb3+ and SnO2 doped Er3+ thin films are bigger than undoped SnO2 thin films. SnO2 thin films have tetragonal structure with prominent peaks corresponding to (110), (101) and (211) crystal lattice planes. The band gap energy is decreased with the addition of dopant (Tb3+ and Er3+ ion) in sensitized SnO2 thin films. The PL emission peaks of SnO2:Tb3+ sensitized with eosin Y corresponding to the characteristic D?Ftransitions between the energy levels of Tb3+ ion. The addition of erbium (Er3+) to the SnO2 sol results in PL emission peaks that are associated with G?Iand H? I transitions in Er3+ ion

Kesuperkonduksian

Buku ini mengandungi beberapa bab iaitu kandungan, prakata, unit-unit, simbol-simbol, bab 1 keadaan superkonduktif, pensuperkonduksi, litar-litar superkonduksi, bab 2 sifat-sifat magnetik keadaan superkonduktif, spesimen-spesimen pukal-kesan meissner, medan di luar satu spesimen pukal, bab 3 pensuperkonduksi jenis 1, dua jenis pensuperkonduksi, peralihan superkonduktif dalam satu medan magnet, bab 4 pensuperkonduksi-pensuperkonduksi jenis 2, keadaan bercampur, garis-garis vorteks, bab 5 sifat semulajadi keadaan superkonduktif,, ciri-ciri elektromagnetik statik, tenaga sempadan, indeks perkara