236 research outputs found
Comparison of two jejunal anastomosis techniques in dogs treated preoperatively with dexamethasone
The aim of this study was to evaluate effects of steroidal antiinflammatory drugs that given before surgery on two intestinal anastomosis techniques in dogs. Thirty-two adult local breed dogs were equally and randomly divided into 2 groups: group 1: consist of 16 dogs underwent apposition End-To-End jejunal anastomosis using simple interrupted suture technique and divided this into 2 subgroups: subgroup A: consist of 8 dogs treated preoperatively for 15 days with dexamethasone at a dose of (0.1ml/kg) given I/M. Subgroup B: control group consists of 8 dogs not treated with dexamethasone. Group 2: consist of 16 dogs underwent inverted End-To-End jejunal anastomosis using continuous Lumbert suture pattern and divided this into 2 subgroups: subgroup A: consists of 8 dogs treated preoperatively for 15 days with dexamethasone at a dose of (0.1ml/kg) given I/M. Subgroup B: control group consist of 8 dogs not treated with dexamethasone. The result showed the adhesion at anastomosis site with omentum was more severe in the group one when compared with the group two. The degree of stenosis rate was lower in group one after 7 days of operation (22.7±8.2) while the degree of stenosis rate was higher in the group two after 15 days (54.9±4.1). The anastomotic bursting pressure was significantly lower in the all steroidal subgroups at 7 and 15 days compared with the control subgroups
SIFAT FISIK VULKANISAT KARET DENGAN BAHAN PENGISI VARIASI TANAH LIAT DI BERBAGAI LAPISAN AREA TAMBANG PT. BUKIT ASAM (PERSERO) TBK.
This study aims to study the physical characteristics of vulcanized rubber using various clay fillers from layers in the PT. Bukit Asam (Persero) Tbk .. This research was conducted 6 formulas (1,2,3,4,5,6), each variation of clay type INT A2-B1, OBA1, Lower C, INT A1-A2, INT B2-C, INT B1-B2. Then with the same variation carried out the addition of chemicals in the form of JHS-69 and PEG 4000 in each of the 6 formulas as much as 1 phr. The natural rubber used is RSS-1 then rubber is modified and vulcanized along with other process materials in the open mill. Based on the results of the study it has been analyzed that rubber compound number 4 using JH-S69 is better than other rubber compounds, which have a tensile strength value of 17.2 Mpa, elongation at break of 670%, modulus of 300% 4 Mpa, and tear strength 33 kN / m. Whereas the best rubber compound using PEG 4000 is compound number 2 which has a tensile strength value of 16.6 Mpa, elongation at break of 690%, modulus of 300% 2.4 Mpa, and tear strength 28.8 kN / m. From the results of the analysis of the physical properties, the two compounds meet the SNI 0778:2009 standards to be used as shoe soles products
Corrosion Resistance Enhancement in Acidic solution for Austenitic Stainless Steel by Gas-Phase Hybrid Deposition Process
In acidic environments the corrosion rate of stainless steels is considered high, this is due to pitting occurrence in concentrated chloride environments. The Austenitic steels such as type 316 stainless steel generally not recommended for Hydrochloric acid storage in petroleum planets except when solutions are very dilute and at room temperature, otherwise pitting may occur. In this work, a multicomponent coating (Ti-B-N-C) was deposited on the austenitic stainless steels (AISI 316) that used in petroleum industry. The coating process has been achieved by mixed vapor deposition technique; this was done in attempt to improve the resistance to pitting corrosion for austenitic stainless steels surface. The structural characterization for the deposited Ti-Base coating was done by using XRD technique, and the Scanning Electron Microscopy (SEM). Electrochemical corrosion tests have been performed by using electrochemical test in 0.25M hydrochloric acid (HCl) as an aqueous solution at 22˚C to obtain the anodic polarization curves for the coated surfaces. Several interesting observations have been made During the test. As expected, the surface of the AISI 316 suffers from a sudden increase in the current density at the potential above 1500 mV due to the occurrence of pitting corrosion. In addition, the Ti-B-C-N coating surfaces show great future in reducing the current density of the steel surface in the anodic region, indicating improved pitting resistance for all Ti-based coating samples. No evidence for pitting corrosion was observed in the coated surfaces during electrochemical test even at potentials up to 2000 mV, instead, general corrosion was observed for the samples that was deposited at 750˚C since low potential values was observed for these samples
Design of Nano-Inhibitor of Dichlorobenzene and It's Adduct and Study of Its Structural and Electronic Properties: DFT Calculations
Corrosion in oil pipelines is one of the biggest problems in the oil sector companies because of the high cost resulted from repairing the corroded parts, or replace it with another non-corroded ones, so, in this research, we study the design of nano-inhibitor and study of its structural and electronic properties of dichlorobenzene molecule (C6H4Cl2) and the effect of adding groups of Hydroxy on those properties, density functional theory (DFT) at B3LYP level with (6-31G) basis sets. The study included four new molecules, which are including monohydroxy dichlorobenzene molecule, dihydroxy dichlorobenzene, trihydroxy dichlorobenzene, and tetrhydroxy dichlorobenzene. The structural and electronic calculations have been done by using Gaussian 09 program and Gaussian View in DFT calculations. The geometry optimization using both methods for dichlorobenzene (nano-inhibitor) and group’s Hydroxy molecules has been found in good agreement with experimental data. While the electronic properties included calculate total energy, ionization potential, electron affinity, chemical potential, electronegativity, electrochemical hardness and electronic softness for molecules under study. These results show that the energy gap reduced with the increase of the number of groups; also, the electron affinity and electronegativity for dichlorobenzene molecule Ben-Cl-2OH are the lowest, while the chemical potential be the highest for the same inhibitor. Nano-inhibitor result reduces corrosion of internal surfaces of tubes that used for transporting oil and gas to the importance of these molecules in terms of their high ability for interaction. Those dichlorobenzene can restrain corrosion from claiming steel toward framing an inactive layer for this molecule on the metal's surface
Colossal anisotropy in diluted magnetic topological insulators
We consider dilute magnetic doping in the surface of a three dimensional
topological insulator where a two dimensional Dirac electron gas resides. We
find that exchange coupling between magnetic atoms and the Dirac electrons has
a strong and peculiar effect on both. First, the exchange-induced single ion
magnetic anisotropy is very large and favors off-plane orientation. In the case
of ferromagnetically ordered phase we find a colossal magnetic anisotropy
energy, of the order of the critical temperature. Second, a persistent
electronic current circulates around the magnetic atom and, in the case of a
ferromagnetic phase, around the edges of the surface.Comment: 4 pages, 3 figure
Cellular uptake and retention of nanoparticles: Insights on particle properties and interaction with cellular components
The utilization of nanomaterials in the biological and medical field is quickly progressing, particularly in areas where traditional diagnostics and treatment approaches have limited success. The success of nanomaterials in medical products such as biomedical implants, wound dressings and drug delivery systems rely upon their effective interaction between the extracellular matrix, cells, and intracellular components. Upon contact with mammalian cells, nanoparticles (NPs) begin to interact with the extracellular matrix, cell membrane, cytoplasmic proteins, nucleus, and other cellular organelles, which result in nanoparticle internalization and subsequent cellular responses. Such responses elicited by the mammalian cells as a result of the cell-nanomaterials interactions, both at the cellular and molecular level, are mainly determined by the morphological, chemical, and surface characteristics of the nanomaterials themselves. This review provides an overview of how such different attributes, such as chemical nature, size, shape, surface charge, topography, stiffness, and functional features of nanomaterials, influence the cell-nanomaterials interactions.Scopu
Involvement of ethylene carbonate on the enhancement H+ carriers in structural and ionic conduction performance on alginate bio-based polymer electrolytes
This study investigates the structural and ionic conduction performance with the involvement of ethylene carbonate (EC) in a bio-based polymer electrolytes (BBPEs) system, based on alginate doped glycolic acid (GA). The solution casting technique was used to successfully prepare the BBPEs which were characterized with various approaches to evaluate their ionic conduction performance. It was revealed that at ambient temperature, an optimum ionic conductivity of 9.06 × 10−4 S cm−1 was achieved after the addition of 6 wt% EC, with an observed improvement of the amorphous phase and thermal stability. The enhancement of ionic conduction properties is believed to be due to the protonation (H+) enhancement, as proven by FTIR and TNM studies. The findings show that the developed alginate-GA-EC is a promising candidate for use as electrolytes in electrochemical devices that are based on H+ carriers
Influence of AlN passivation on thermal performance of AlGaN/GaN high-electron mobility transistors on sapphire substrate: A simulation study
This work describes the self-heating effects on the behavior of AlGaN/GaN-based high-electron Mobility Transistors (HEMTs), which are grownon Sapphire substrate, using electro-thermal TCAD simulations. The proposed device, passivated with AlN/SiN, demonstrates more excellent thermal performance than the conventional one with SiN passivation due to the introduction of additional AlN on top of the device, which acts as a heat spreader. The electro-thermal simulations have carried out for different AlN thicknesses (0 µm to 25 µm), and the device with 5 µm AlN shows better performance compared to others. The proposed AlN/SiN stacked passivation HEMT shows a comparatively small lattice temperature of 418 K, whereas the conventional HEMT with SiN passivation shows 578 K. All the devices (gate length, LG = 1 µm) switch from OFF- to ON-states using the voltage, VGS from −10 V to 0 V with fixed bias, VDS = 5 V. The values of saturation drain current density (IDSS) and transconductance (gm) are 0.7 A/mm and 173 mS/mm for the proposed HEMT with 5 µm AlN considering the thermal simulation model. In contrast, the conventional device demonstrates those of 0.42 A/mm and 109 mS/mm, respectively. The ∼ 0.32 A/mm of drain current recover for the proposed device with 5 µm AlN from a conventional device because of the reduction of self-heating effects. Our study reveals that the AlN/SiN passivation HEMTs are a promising technology for high-power switching and microwave applications without significant reduction in device performance at high drain bias
Identifying topological edge states in 2D optical lattices using light scattering
We recently proposed in a Letter [Physical Review Letters 108 255303] a novel
scheme to detect topological edge states in an optical lattice, based on a
generalization of Bragg spectroscopy. The scope of the present article is to
provide a more detailed and pedagogical description of the system - the
Hofstadter optical lattice - and probing method. We first show the existence of
topological edge states, in an ultra-cold gas trapped in a 2D optical lattice
and subjected to a synthetic magnetic field. The remarkable robustness of the
edge states is verified for a variety of external confining potentials. Then,
we describe a specific laser probe, made from two lasers in Laguerre-Gaussian
modes, which captures unambiguous signatures of these edge states. In
particular, the resulting Bragg spectra provide the dispersion relation of the
edge states, establishing their chiral nature. In order to make the Bragg
signal experimentally detectable, we introduce a "shelving method", which
simultaneously transfers angular momentum and changes the internal atomic
state. This scheme allows to directly visualize the selected edge states on a
dark background, offering an instructive view on topological insulating phases,
not accessible in solid-state experiments.Comment: 17 pages, 10 figures. Revised and extended version, to appear in EJP
Special Topic for the special issue on "Novel Quantum Phases and Mesoscopic
Physics in Quantum Gases". Extended version of arXiv:1203.124
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