Oxygen-vacancy-related giant permittivity and ethanol sensing response in SrTiO3-δ ceramics

The ethanol sensing properties of SrTiO3-δ (δ = 0.075 and 0.125) ceramics was analyzed by dielectric measurements. The ceramics were prepared by solid state reaction method followed by the creation of oxygen vacancies-δ, through a thermal activated process. The crystal symmetry, space group and unit cell dimensions were derived from the X-ray diffraction (XRD) data using FullProf software whereas grain's size distribution was assessed by scanning electron microscopy (SEM). The prepared samples have been analyzed by impedance spectroscopy over the frequency range from 100 Hz to 1 MHz and temperature range from 240 to 340 K. The dielectric properties of SrTiO3-δ ceramics showed a quite remarkable stability of giant permittivity (>104) as well as a low dielectric loss, which open ways for several applications such as over voltage protections of electronic devices. A low-frequency dielectric relaxation behavior was found, and the carriers for electrical conduction result from the first-ionization of oxygen vacancies. The conductivity and gas sensitivity of SrTiO3-δ-based sensors were investigated. Results demonstrated that the conductivity decreases after the introduction of the ethanol gas, and p-type semiconductor gas-sensing materials were obtained. Both characteristics present higher responses at lower optimal operating temperatures.publishe

Hydrodynamics in Two-Phase Turbulent Boundary Layers

The corrections for log law must be taken into account the presence of bubbles in the two phase turbulent boundary layer. In the present study, a logarithmic law for the wall based on the supposition of additional turbulent viscosity associated with bubble wakes in the boundary layer was proposed for bubbly flows. An empirical constant accounting both for shear induced turbulence interaction and for non-linearity of bubble was determined for the new wall law, this constant was deduced from experimental measurements. In the case of a turbulent boundary layer with millimetric bubbles developing on a vertical flat plate, the wall friction prediction achieved with the wall law was compared to the experiences. We obtained a good concordance between experimental and numerical result. This significant agreement for wall friction prediction was particularly important for the low void fraction when bubble induced turbulence have a considerable role

Investigating the structural, morphological, dielectric and electric properties of the multiferroic (La0.8Ca0.2)0.9Bi0.1FeO3 material

The (La0.8Ca0.2)0.9Bi0.1FeO3 (LCBFO) compound has been synthesized by the sol-gel method and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Raman spectroscopy and electrical impedance spectrometry. XRD results revealed that (La0.8Ca0.2)0.9Bi0.1FeO3 crystals are orthorhombic, belonging to the Pnma space group. The SEM measurements showed that the sample presents a large distribution of nano-grains connected to each other. The relaxation process and the electrical conductivity are awarded to the same type of charge carriers characterized by similar values of the activation energy determined from loss factor tangent tg δ( ), the imaginary part of the permittivity and from the Modulus spectrum. The ac-conductivity was analysed to examine the conduction mechanism, using the Jonscher’s universal power-law given by: = +σ ω σ Aω( )ac dc s. Based on the parameter s behavior, the conductivity was studied according to the NSPT model (non-overlapping small polaron tunneling).publishe

CO sensing characteristics of In-doped ZnO semiconductor nanoparticles

Abstract A study on the CO sensing characteristics of In-doped ZnO semiconductor nanoparticles (IZO NPs) prepared by a modified sol–gel technique is reported. The morphological and microstructural features of IZO NPs with various dopant concentrations (1 at.%, 2 at.%, 3 at.%, and 5 at.% In) were investigated by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The influence of indium doping on defect characteristics of ZnO was also investigated by photoluminescence (PL). A thick film of IZO NPs was deposited by screen printing on an alumina substrate provided with a pair of Pt interdigitated electrodes to fabricate a simple conductometric sensor platform. The as fabricated In-doped ZnO sensors showed enhanced sensitivity to CO gas with respect to pure ZnO one. Sensors with low dopant loading (1 at.% and 2 at.% In) were found to be more sensitive with shorter response and recovery times than those with high dopant loading

Stapling and Section of the Nasogastric Tube during Sleeve Gastrectomy: How to Prevent and Recover?

Bariatric surgery has become an integral part of morbid obesity treatment with well-defined indications. Some complications, specific or not, due to laparoscopic sleeve gastrectomy (LSG) procedure have recently been described. We report a rare complication unpublished to date: a nasogastric section during great gastric curve stapling. A 44-year-old woman suffered of severe obesity (BMI 36.6 kg/m2) with failure of medical treatments for years. According to already published technique, a LSG was performed. Six hours postoperatively, a nurse removed the nasogastric tube according to the local protocol and the nasogastric tube was abnormally short, with staples at its extremity. Surgery was performed with peroperative endoscopy. In conclusion, this is the first publication of a nasogastric section during LSG. Therefore we report this case and propose a solution to prevent its occurrence. To avoid this kind of accident, we now systematically insert the nasogastric tube by mouth through a Guedel cannula. Then, to insert the calibrating bougie, we entirely withdraw the nasogastric tube

DEMOCRATIZATION AND PERFORMANCE OF GENERAL ELECTION COMMISSION ON IMPLEMENTATION OF SIMULTANEOUSLY PROVINCE REGIONAL ELECTION

ABSTRACT The General Election Commission (KPU) has finished carrying out regional head elections in 17 provinces in 2018. The implementation of this regional head election is the first history of the simultaneous implementation of governor elections. KPU's performance was highlighted in this simultaneous regional head election. The number of voters in the 2018 Governor and Deputy Governor Election amounted to 143,667,935. Community participation in the 2018 Concurrent Local Election is in the range of 72%. KPU has targeted community participation of 77 percent. Of the 17 provinces that held gubernatorial elections, only Papua province exceeded the voter participation target. While the disability voter participation is on average 49 percent with the highest disability voter level in Maluku at 96 percent and the lowest in Central Java 32 percent. Furthermore, the findings related to ballots are invalid. Invalid ballots in the election of governors and deputy governors were 3,098,239, equivalent to 3 percent of all election logistics used. The most invalid ballots are found in Central Java Province, namely 778,805 ballots, East Kalimantan as many as 50,110 ballots, and East Java with 782,027 ballots. The research conducted found results that there were alleged violations that occurred in the 2018 simultaneous regional election. It was suspected that there were 1,095 violation reports and 2,038 violation findings. The number of violations in the Regional Head Election this time is greater than the previous election. This is due to the fact that the number of regions holding this year's Election is bigger than the 2017 election, which is 101 regions. The details of these violations were 291 criminal violations, 853 administrative violations, 114 violations of the code of ethics, 712 violations of other laws, and 619 categories not violations or not proven. Regarding voter voting rights, the high number of Transfer Voters List (DPPH) and Additional Voters List (DPTb). Of the total 143,667,935 people who voted in the simultaneous regional elections in 2018, there were 173,553 voters from DPPH and 2,032,556 voters from DPTb. To note, the number of DPTb is the basis for evaluating the process of updating voter data throughout the election stages. So that the performance of KPU voters' data collection is in the quite effective category

Controllable synthesis, XPS investigation and magnetic property of multiferroic BiMn2O5 system: The role of neodyme doping

In this work, a novel series of multiferroic materials BiMn2O5 doped by Neodyme has been prepared by a sol-gel method at low temperature. The crystallographic studies using X-ray diffraction and Rietveld Refinement techniques showed the formation of single-phase samples for all compositions, crystallizing in a mullite-type orthorhombic perovskite structure, space group Pbam (Z=4). The SEM techniques confirmed the formation of single-phase materials with excellent mapping distribution. Raman and infrared spectroscopic measurements were performed and combined with lattice dynamics simulations to describe the room-temperature vibrational properties of all samples. The X-ray Photoelectron Spectroscopy (XPS) were measured in the energy range of 0–1400 eV at room temperature. The Fermi level EF was defined with the accuracy of 0.127, 0.32 and 0.48 eV for BiMn2O5, Bi0.9Nd0.1Mn2O5 and Bi0.8Nd0.2Mn2O5 respectively. The X-ray photoelectron spectroscopy shows the existence of Mn4+ state. Magnetic measurements indicate Neél temperature TN at 31, 40 and 61 K for BiMn2O5, Bi0.9Nd0.1Mn2O5 and Bi0.8Nd0.2Mn2O5 respectively

Therapeutic Properties of Vanadium Complexes

Vanadium is a hard, silver-grey transition metal found in at least 60 minerals and fossil fuel deposits. Its oxide and other vanadium salts are toxic to humans, but the toxic effects depend on the vanadium form, dose, exposure duration, and route of intoxication. Vanadium is used by some life forms as an active center in enzymes, such as the vanadium bromoperoxidase of ocean algae and nitrogenases of bacteria. The structure and biochemistry of vanadate resemble those of phosphate, hence vanadate can be regarded as a phosphate competitor in a variety of biochemical enzymes such as kinases and phosphatases. In this review, we describe the biochemical pathways regulated by vanadium compounds and their potential therapeutic benefits for a range of disorders including type 2 diabetes, cancer, cardiovascular disease, and microbial pathology

Hopping conduction mechanism and impedance spectroscopy analyses of La0.70Sr0.25Na0.05Mn0.70Ti0.30O3 ceramic

The perovskite sample La0.7Sr0.25Na0.05Mn0.7Ti0.3O3 (LSNM0.70T0.30) was produced via a solid-state route process. The frequency dependence of electrical conduction plot established that according to the Jonscher law. The electrical conduction process was based on both theoretical conduction models assigned to the non-overlapping small polaron tunneling model at low temperatures and correlated barrier hopping mechanism at high temperatures. Detailed investigation of impedance data revealed a non-Debye-type relaxation occurring in the polycrystalline. In addition, the dielectric response confirmed the dominance of the Maxwell–Wagner model and Koop’s phenomenological theory effect in conduction phenomenon. The values of permittivity is high for LSNM0.70T0.30 were observed. These values make this composition interesting for microelectric applications. In the thermal study, the relaxation processes observed by electrical conductivity, impedance, and modulus are associated with singly and doubly ionized oxygen vacancies for the lower and higher temperature, respectively. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Majmaah University, MU: R-2021-121The author would like to thank Deanship of Scientific Research at Majmaah University for supporting this work under Project Number No. R-2021-121