Studies on the Selective Oxidation Activity of Iron-Tellurium-Oxide Catalysts.

The selective oxidation of 1-butene to 1,3-butadiene and propylene to acrolein are important industrial processes. One of the critical factors which determines the feasibility of these processes is selectivity. Since iron oxide has shown potential as a component of a selective mixed oxide catalyst, and tellurium has been used as a promoter for selective oxidation catalysts, this study focusing on the development and investigation of an iron-tellurium mixed oxide catalyst for the selective oxidation of propylene and 1-butene has been undertaken. The study includes kinetic and mechanistic investigations, and simultaneous activity/selectivity and spectroscopic measurements for iron-tellurium catalysts have been developed. The purpose of this work is to characterize the role of tellurium in iron-tellurium mixed oxide selective oxidation catalysts, and to gain insight into other tellurium containing catalysts. Catalysts containing only iron and tellurium have been prepared and the active phase identified by X-ray powder diffraction as Fe(,2)TeO(,6). The catalysts show very good yields for the oxidation of 1-butene to butadiene and propylene to acrolein. The reaction orders and activation energies for the oxidation of propylene and 1-butene to both selective and extensive oxidation products have been determined. Selective oxidations of propylene and 1-butene are both first- and zero-order in hydrocarbon and oxygen partial pressures, and with activation energies of 35 and 33 kcal/mole, respectively. Extensive oxidation of propylene and 1-butene are first-order and half-order, respectively, in both hydrocarbon and oxygen partial pressures, and with activation energies of 41 and 29 kcal/mole, respectively. Pulse experiments have shown that the catalyst has different sites for the oxidation and isomerization reactions. However, the active sites for the selective and extensive oxidation reactions appear to be identical at first and rate-determining step. From Mossbauer and IR spectroscopies we infer that iron does not undergo oxidation state shifts during the selective oxidation process. Tellurium (VI) is thought to be the active species while iron simply provides a suitable environment for tellurium (VI) to exist

Multi-instrument Comparative Study of Temperature, Number Density, and Emission Measure during the Precursor Phase of a Solar Flare

We present a multi-instrument study of the two precursor brightenings prior to the M6.5 flare (SOL2015-06-22T18:23) in the NOAA Active Region 12371, with a focus on the temperature (T), electron number density (n), and emission measure (EM). The data used in this study were obtained from four instruments with a variety of wavelengths, i.e., the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA), in six extreme ultraviolet (EUV) passbands; the Expanded Owens Valley Solar Array (EOVSA) in microwave (MW); the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in hard X-rays (HXR); and the Geostationary Operational Environmental Satellite (GOES) in soft X-rays (SXR). We compare the temporal variations of T, n, and EM derived from the different data sets. Here are the key results. (1) GOES SXR and AIA EUV have almost identical EM variations (1.5-3x10^48 per cm^3) and very similar T variations, from 8 to 15 million Kelvin (MK). (2) Listed from highest to lowest, EOVSA MW provides the highest temperature variations (15-60 MK), followed by RHESSI HXR (10-24 MK), then GOES SXR and AIA EUV (8-15 MK). (3) The EM variation from the RHESSI HXR measurements is always less than the values from AIA EUV and GOES SXR by at most 20 times. The number density variation from EOVSA MW is greater than the value from AIA EUV by at most 100 times. The results quantitatively describe the differences in the thermal parameters at the precursor phase, as measured by different instruments operating at different wavelength regimes and for different emission mechanisms.Comment: 10 pages, 7 figure

Poly[[tetra­aqua­bis­(μ3-5-carboxybenzene-1,2,4-tri­carboxyl­ato)tricadmium] tetra­hydrate]

There are three independent CdII ions in the title complex, {[Cd3(C10H3O8)2(H2O)4]·4H2O}n, one of which is coordinated by four O atoms from three 5-carboxybenzene-1,2,4-tri­carboxyl­ate ligands and by two water mol­ecules in a distorted octa­hedral geometry. The second CdII ion is coordinated by five O atoms from four 5-carboxybenzene-1,2,4-tri­carboxyl­ate ligands and by one water mol­ecule also in a distorted octa­hedral geometry while the third CdII ion is coordinated by five O atoms from three 5-carboxybenzene-1,2,4-tri­carboxyl­ate ligands and by one water mol­ecule in a highly distorted octa­hedral geometry. The 5-carboxybenzene-1,2,4-tri­carboxyl­ate ligands bridge the CdII ions, resulting in the formation of a three-dimensional structure. Intra- and inter­molecular O—H⋯O hydrogen bonds are present throughout the three-dimensional structure

Prediction and control on vibro-acoustic environment of vessel engine room floating cabins

With the engine room of certain training ship for navigation teaching being the prototype, the numerical model was developed for three cabins with floating cabin to predict the structure-borne noise (SBN) in ship cabins. The finite element model of multi-tanks structure was built when the vibro-acoustic coupling system was simplified. The predicted results for SBN were compared with the measurements done on a cabin mock-up. The effects of vibration isolator and constraint damping materialss were investigated. Comparisons of the predicted results and the experimental results showed that the developed model could be an effective tool for predicting SBN in ship cabins. The elastic mount installed positions on the auxiliary diesel engine are selected as the force excitation points. The finite element/boundary element method to predict sound pressure level (SPL) of the machinery control room and mechanical workshops of the ship, The sound pressure color nephogram of symmetrical field points on two sides is compared and analyzed, thus the degree of contribution of all bulkheads to the SPL in the right ear position of the duty engineer is acquired. And the floating cabins design based on floating floor is verified to effectively decrease the noise in cabin. The method and process of predicting vibration and sound of the vessel engine room are summarized, which could be a reference for reducing vibration and noise of ships

Document Clustering in Antimicrobial Peptides Research

Antimicrobial peptides are small peptides encoded by genes. The research area of antimicrobial peptides has attracted intense attention in recent years because “their potential use in the cure of infectious diseases caused by pathogens that have become counteractive to traditional antibiotics” (Boman 1994). There exist huge amount of antimicrobial peptides research articles and this number is continuously increasing. Although some biomedical databases, such as PubMed, have been well established, they provide only query-based information retrieval and end-users need to manually find out relevant information from thousands of retrieved articles. The objective of this paper is to apply one of the text mining techniques, document clustering, which groups similar documents into clusters, to text documents collected from PubMed using keyword “antimicrobial peptides”. The results of our work can help researchers to discover meaningful groups of antimicrobial peptides articles in an efficient manner