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Shaoying Li, Xiaojun Xi, Yiwa Luo, Mingtao Mao, Xiao Shi, Jing Guo, Hanjie Guo
In this paper, the precipitation of carbide and wear loss of high-carbon 8 mass% Cr tool steel at two tempering conditions (i.e., 773⁻803 K and 823⁻853 K) were studied by INCA Steel, EPMA-1720H, XRD, and ML-10 tester. The results show that the particles of test steels include the carbides (Cr₇C₃ and Cr23 C₆) and carbides nucleated on Al₂O₃. When carbides are of the same size, the number of carbides in test steel at a tempering temperature of 773⁻803 K is greater than that at a tempering temperature of 823⁻853 K, especially when the size of carbides is less than 5 μm...
December 7, 2018: Materials
Ben Buse, Jon Wade, Xavier Llovet, Stuart Kearns, John J Donovan
Secondary fluorescence (SF), typically a minor error in routine electron probe microanalysis (EPMA), may not be negligible when performing high precision trace element analyses in multiphase samples. Other factors, notably wavelength dispersive spectrometer defocusing, may introduce analytical artifacts. To explore these issues, we measured EPMA transects across two material couples chosen for their high fluorescence yield. We measured transects away from the fluorescent phase, and at various orientations with respect to the spectrometer focal line...
December 3, 2018: Microscopy and Microanalysis
Fenghou Xie, Chongyun Shao, Meng Wang, Qinling Zhou, Fengguang Lou, Wenbin Xu, Chunlei Yu, Suya Feng, Lili Hu
Yb3+ /Al3+ co-doped silica fibers (YDFs) with almost identical core glass compositions were prepared using the sol-gel and modified chemical vapor deposition (MCVD) methods. The photodarkening (PD) and laser performance before and after the PD process were tested under 974 nm pumping. The doping homogeneity of Yb3+ ions and clusters of Yb3+ ions in preform slices of these two fibers were investigated via optical absorption spectroscopy, photoluminescence emission spectra, electron probe microanalysis (EPMA), and low-temperature (4 K) electron paramagnetic resonance (EPR)...
October 29, 2018: Optics Express
Soroush Modabberi
Muteh Gold Deposit is the biggest active gold district in Iran consisting of two mines, Senjedeh and Chah-Khatoun, and seven mineral occurrences. Senjedeh has been mined about 20 years ago and was recently closed because of the depletion of the reserves. Chah-Khatoun went into operation few years ago. During the previous decades, more than 22 Mt of low-grade wastes has been produced from both mines. The wastes are assumed to be a possible source of gold, especially with recent increase in the world gold prices...
November 19, 2018: Environmental Monitoring and Assessment
Paula López-Arce, Fernando Garrido, Javier García-Guinea, Andreas Voegelin, Jörg Göttlicher, Jose Miguel Nieto
Samples of an open-air pyrite roasting heap from the 19th century in the Riotinto mine area (SW Spain) and surrounding sediments and soil along a seasonal surface runoff channel were analyzed to study thallium (Tl) phase transformations during historical roasting of Tl-bearing arsenian pyrite, secondary weathering processes, Tl dispersion and current environmental pollution. Results from Electron Probe Microanalyses (EPMA) indicate an even distribution of Tl in pyrite grains of an ore sample (22 mg kg-1 total Tl), suggesting that Tl is incorporated in the pyrite structure rather than in discrete Tl-sulfide microparticles...
January 15, 2019: Science of the Total Environment
Weimin Bai, Guanglong Xu, Mingyue Tan, Zhijie Yang, Lijun Zeng, Di Wu, Libin Liu, Ligang Zhang
β-type (with bcc structure) titanium alloys have been widely used as artificial implants in the medical field due to their favorable properties. Among them, Ti-Mo alloy attracted numerous interests as metallic biomaterials. Understanding of kinetic characteristics of Ti alloys is critical to understand and manipulate the phase transformation and microstructure evolution during homogenization and precipitation. In this work, diffusion couple technique was employed to investigate the diffusion behaviors in bcc Ti-Mo-Zr alloys...
October 8, 2018: Materials
R Böttcher, H T Langhammer, S Kücker, C Eisenschmidt, S G Ebbinghaus
Electron paramagnetic resonance (EPR) investigations of BaTiO3   +  0.04 BaO  +  x/2 Fe2 O3 (0.007  ⩽  x  ⩽  0.05) ceramics and BaTi0.98 Fe0.02 O3 single crystals were performed to study the incorporation of Fe ions in the hexagonal 6H-BaTiO3 lattice and their defect properties. The samples were characterized by x-ray diffraction and wavelength-dispersive x-ray electron probe microanalysis. EPR spectra were recorded both in X- and Q-bands at room temperature. Angle-dependent single crystal EPR investigations and simulations of the ceramic powder EPR spectra revealed three different centers, which can be attributed to Fe3+ ions incorporated on crystallographically different Ti sites...
October 24, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Zhuguo Li, Mariko Nagashima, Ko Ikeda
Long-term immobilization ratios of strontium (Sr2+ ) and cesium (Cs⁺) in paper sludge ash-based geopolymer (PS-GP) were investigated in one year. PS-GP paste specimens were prepared in the conditions of 20 °C and 100% R.H., using two kinds of paper sludge ash (PS-ash). Two kinds of alkaline solution were used in the PS-GP as activator. One was prepared by diluting aqueous Na-disilicate (water glass) with seawater. Another was a mixture of this solution and caustic soda of 10 M concentration. When seawater was mixed into the alkaline solution, unstable fixations of Sr2+ and Cs⁺ were greatly improved, resulting stable and high immobilization ratios at any age up to one year, no matter what kind of PS-ash and alkaline solution were used...
August 24, 2018: Materials
J M Xiang, G B Mi, S J Qu, X Huang, Z Chen, A H Feng, J Shen, D L Chen
The high-temperature structural applications of Ti2 AlNb-based alloys, such as in jet engines and gas turbines, inevitably require oxidation resistance. The objective of this study is to seek fundamental insight into the oxidation behavior of a Ti2 AlNb-based alloy via detailed microstructural characterization of oxide scale and scale/substrate interface after oxidation at 800 °C using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM)...
August 24, 2018: Scientific Reports
S E Challinger, I D Baikie, G Flannigan, S Halls, K Laing, L Daly, N Nic Daeid
Most traditional techniques to recover latent fingermarks from metallic surfaces do not consider the metal surface properties and instead focus on the fingermark chemistry. The scanning Kelvin probe (SKP) technique is a non-contact, non-destructive method, used under ambient conditions, which can be utilised to recover latent prints from metallic surfaces and does not require any enhancement techniques or prevent subsequent forensic analysis. Where a fingermark ridge contacted the metal, the contact potential difference (CPD) contrast between the background surface and the fingermark contact area was 10-50mV...
October 2018: Forensic Science International
Svetlana Shkolyar, Jack D Farmer
Assessing biosignature preservation potential (BPP) in ancient habitable environments on Mars is a top NASA priority. We address this goal through the study of Miocene-Pliocene evaporites of the Verde Formation (central Arizona). We assessed the effects of diagenesis on BPP, integrating outcrop-scale observations with six lab analyses: thin-section petrography, X-ray diffraction, Raman spectroscopy, total organic carbon (TOC), electron probe microanalysis (EPMA), and visible to near-infrared (VNIR) reflectance spectroscopy...
November 2018: Astrobiology
Shenghui Guo, Xiaolei Ye, Liang Wang, Sivasankar Koppala, Li Yang, Tu Hu, Jiyun Gao, Ming Hou, Longtao Hu
Microwave pressureless sintering (MPS) method is successfully applied in the fabrication of Cu based metallic matrix for diamond tools. The main purpose of this work is to obtain better mechanical properties when the metal binder of the diamond tools was prepared by the MPS method. The orthogonal experimental method is adopted to design the sintering process parameters. The optimized experimental conditions are suggested as 880 °C of sintering temperature, 375 MPa of cold pressure, and 35 min of withholding time...
August 16, 2018: Materials
Franck Tessier
Nitrogen (and also oxygen) determination has become an important parameter to characterize (oxy)nitride materials for many properties and applications. Analyzing such anions with accuracy is still a challenge for some materials. However, to date, a large panel of methodologies is available to answer this issue with relevant results, even for thin films. Carrier gas hot extraction techniques and electron probe microanalysis with wavelength dispersive spectroscopy (EPMA-WDS) look attractive to analyze bulk materials and thin films, respectively...
August 1, 2018: Materials
Yanan Fang, Sam J Page, Gregory J Rees, Maxim Avdeev, John V Hanna, Tim J White
Vanadate ellestadites Ca10 (SiO4 ) x (VO4 )6-2 x (SO4 ) x Cl2 , serving as prototype crystalline matrices for the fixation of pentavalent toxic metals (V, Cr, As), were synthesized and characterized by powder X-ray and neutron diffraction (PXRD and PND), electron probe microanalysis (EPMA), Fourier transform infrared spectroscopy (FTIR), and solid-state nuclear magnetic resonance (SS-NMR). The ellestadites 0.19 < x < 3 adopt the P63 / m structure, while the vanadate endmember Ca10 (VO4 )6 Cl2 is triclinic with space group P1̅...
August 6, 2018: Inorganic Chemistry
Tzu-Ruei Yang, Ying-Hsuan Chen, Jasmina Wiemann, Beate Spiering, P Martin Sander
The cuticle layer consisting mainly of lipids and hydroxyapatite (HAp) atop the mineralized avian eggshell is a protective structure that prevents the egg from dehydration and microbial invasions. Previous ornithological studies have revealed that the cuticle layer is also involved in modulating the reflectance of eggshells in addition to pigments (protoporphyrin and biliverdin). Thus, the cuticle layer represents a crucial trait that delivers ecological signals. While present in most modern birds, direct evidence for cuticle preservation in stem birds and non-avian dinosaurs is yet missing...
2018: PeerJ
Parinya Chindudsadeegul, Matinee Jamkratoke
Regarding gemstone identification, the effect of heat treatment under reduction condition to optical and luminescence properties of natural green apatite (Ca5 (PO4 )3 OH, F, Cl) from Madagascar has been investigated. Although electron microprobe analysis (EPMA) shows a luminescence defect of rare earth element such as Ce (0.47%), Pr (0.22%) and Nd (0.15%), however original sample does not show luminescence properties. With consecutive heating process, the color alteration from green to colorless of samples, and also the enhancement of luminescence properties of Ce3+ in natural apatite was observed...
November 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Seishi Hagihara, Jun Aoyama, Daniel Limbong, Katsumi Tsukamoto
A total of 261 individuals of the four tropical eel species, Anguilla celebesensis, Anguilla marmorata, Anguilla bicolor pacifica and Anguilla interioris, were collected from 12 locations around Sulawesi Island, Indonesia, to gain knowledge about the riverine distribution of tropical eels. Anguilla marmorata was predominant in the lower reaches of Poso River (94·4% of total eel catch in the sampling area), Poso Lake (93·3%), three small inlet rivers of Tomini Bay (100%) and Laa River (92·3%). Anguilla celebesensis occurred frequently in the inlet rivers of Poso Lake (63·5%)...
July 2018: Journal of Fish Biology
Arash Panahifar, L Dean Chapman, Lynn Weber, Nazanin Samadi, David M L Cooper
Bone acts as a reservoir for many trace elements. Understanding the extent and pattern of elemental accumulation in the skeleton is important from diagnostic, therapeutic, and toxicological perspectives. Some elements are simply adsorbed to bone surfaces by electric force and are buried under bone mineral, while others can replace calcium atoms in the hydroxyapatite structure. In this article, we investigated the extent and pattern of skeletal uptake of barium and strontium in two different age groups, growing, and skeletally mature, in healthy rats...
June 19, 2018: Journal of Bone and Mineral Metabolism
Abhay Kumar, Stephen Joseph, Ludmila Tsechansky, Karen Privat, Inga J Schreiter, Christoph Schüth, Ellen R Graber
Adding biochar to Zn-contaminated soil can immobilize excess Zn and promote plant biomass growth. This was seen previously over the course of a 180-day planted pot trial involving two types of biochar (cattle manure, CM, and grain husk, GH) in a Zn-contaminated soil. Both biochars alleviated Zn-induced phytotoxicity to Ficus by immobilizing Zn and reducing its uptake by the plant, but to different extents. The aim of the current study was to delve into the in-soil mechanisms involved in biochar-mediated Zn immobilization...
June 1, 2018: Science of the Total Environment
S Hagihara, J Aoyama, D Limbong, K Tsukamoto
A total of 261 individuals of the four tropical eel species, Anguilla celebesensis, Anguilla marmorata, Anguilla bicolor pacifica and Anguilla interioris, were collected from 12 locations around Sulawesi Island, Indonesia, to gain knowledge about the riverine distribution of tropical eels. Anguilla marmorata was predominant in the lower reaches of Poso River (94·4% of total eel catch in the sampling area), Poso Lake (93·3%), three small inlet rivers of Tomini Bay (100%) and Laa River (92·3%). Anguilla celebesensis occurred frequently in the inlet rivers of Poso Lake (63·5%)...
June 7, 2018: Journal of Fish Biology
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