Understanding Mud Volcano System Using Hele-Shaw (H-S) Experiment: Seismic Confirmation at East Java Mud Volcano

Numerous researchers have carried out studies on the mud volcano system in East Java. However, there have been no experiments on the mud volcano system's mechanism, including overpressure confirmed by direct subsurface data. Therefore, this study aims to directly evaluate the mud volcano system's mechanism using the Hele-Shaw (H-S) experiment with the subsurface data confirmation. The H-S experiment utilized four primary materials: quartz sand diameter below 250 µm and 320 µm to analogize the porous layer. Gypsum flour clay is the ductile layer, while mud from the Kuwu and Kesongo Mud Volcanoes is the original material from nature. Wax represents impermeable material. The sealing layer is made of wax, and oxygen represents the natural fluids of the rock formation. The overpressured zone is created by pumping oxygen into a layer of quartz sand covered by a wax as an impermeable layer. Pressure is measured digitally, and the process is continuously recorded to produce traceable data. Each material was experimented on individually to determine the critical phase characteristics, valve fault structure geometry, and validation with seismic interpretation. The results indicate that the critical phase of the mud volcano system is characterized by the dome structure at the surface, with high intensify of gas and oil seepage. Piercement structure geometry is shown by plumbing of fluidization zone, which becomes shallower than before. Furthermore, each material's piercement structure geometry shows a consistent pattern, with differences in the density of the fault and pressure structures. Thus, the H-S experiment's validation with seismic interpretation shows a similar geometry in pressure structures and valve faults as the mud volcano system's migration paths.

Synthesis, characterization and antimicrobial activities of heteroleptic metal chelates of isoniazid and 2,2’-bipyridine

The Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of isoniazid (L1) mixed with 2,2-bipyridine (L2) were synthesized and characterized by solubility studies, percentage metal analysis, UV-Vis spectroscopy, IR spectroscopy, conductivity measurements and magnetic moment measurements. The IR spectra revealed that the isoniazid coordinated as a bidentate ligand. In Co(II) and Ni(II) complex it coordinated via the carbonyl oxygen (C=O) and the amide nitrogen, while in the Cu(II), Mn(II) and Zn(II) complexes it coordinated using the amide and carbonyl oxygen via enolization. Bipyridine also bonded to the metals as a bidentate ligand through the pyridinic nitrogen atoms. The magnetic data showed that all the complexes were paramagnetic with values ranging from 1.70 to 5.0 B.M., except [Zn(Is)(Bipy)(H2O)Cl2] which was diamagnetic. The conductivity results revealed that the Cu(II), Mn(II), Zn(II) complexes were 1:1 electrolytes while Co(II) was 1:2 electrolyte and [Ni(Is)(Bipy)Cl2] was non-electrolytic in nature. The antibacterial activities of the ligands and the complexes as evaluated via the agar diffusion method showed that the complexes displayed moderately high antimicrobial activity in comparison with the free ligands when tested against ten strains of bacteria. KEY WORDS: Isoniazid, Electronic structure, Geometry, Antimicrobial activity, Electrolytic nature, Magnetic moment Bull. Chem. Soc. Ethiop. 2020, 34(3), 471-478. DOI: https://dx.doi.org/10.4314/bcse.v34i3.4

Stability and structural properties of vacancy-ordered and -disordered ZrCx

The origin of vacancy ordering in ZrCx is explained considering structure geometry, electronic charge distribution, and atomic bonding features, and linked to stability and volume trends in the vacancy-ordered and -disordered zirconium carbides.

Determination of the Neck Size between Powders during Sintering Process Using Finite Element Methods

Today, sintering considers one of the significant processes that can be used in powder technology to produce a new solid product from powders using thermal energy. Many parameters can be successfully controlled by this process such as temperature, Particle size, process time, structure geometry, powder density, and powder composition. Study and analysis of the behavior of powder during the sintering process was carried out using finite element methods. The simulation provides two styles of discrete method and Qusi-static method. This research contributes to two types of processes in order to simulate the copper powder during the sintering process and to determine the variation by using contact and shrinkage ratios of powder behaviors. Finally, a comparison between the two styles of discrete element method explains how the selected parameters were impacted on the sintering process.