scholarly journals Characterization of structural changes in modern and archaeological burnt bone: Implications for differential preservation bias

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254529
Author(s):  
Giulia Gallo ◽  
Matthew Fyhrie ◽  
Cleantha Paine ◽  
Sergey V. Ushakov ◽  
Masami Izuho ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Bone Mineral ◽  
Structural Changes ◽  
Reference Sample ◽  
Average Crystallite Size ◽  
Average Growth ◽  
Anthropogenic Fire ◽  
Growth Changes ◽  
Calcined Bone ◽  
Burnt Bone

Structural and thermodynamic factors which may influence burnt bone survivorship in archaeological contexts have not been fully described. A highly controlled experimental reference collection of fresh, modern bone burned in temperature increments 100–1200˚C is presented here to document the changes to bone tissue relevant to preservation using Fourier transform infrared spectroscopy and X-ray diffraction. Specific parameters investigated here include the rate of organic loss, amount of bone mineral recrystallization, and average growth in bone mineral crystallite size. An archaeological faunal assemblage ca. 30,000 years ago from Tolbor-17 (Mongolia) is additionally considered to confirm visibility of changes seen in the modern reference sample and to relate structural changes to commonly used zooarchaeological scales of burning intensity. The timing of our results indicates that the loss of organic components in both modern and archaeological bone burnt to temperatures up to 700˚C are not accompanied by growth changes in the average crystallite size of bone mineral bioapatite, leaving the small and reactive bioapatite crystals of charred and carbonized bone exposed to diagenetic agents in depositional contexts. For bones burnt to temperatures of 700˚C and above, two major increases in average crystallite size are noted which effectively decrease the available surface area of bone mineral crystals, decreasing reactivity and offering greater thermodynamic stability despite the mechanical fragility of calcined bone. We discuss the archaeological implications of these observations within the context of Tolbor-17 and the challenges of identifying anthropogenic fire.

Effect of the structural changes on the mechanical properties of the sintered films

2016 ◽  
Vol 12 (1) ◽  
pp. 4141-4144
Author(s):  
Garima Jain
Keyword(s):  
Crystallite Size ◽  
Lattice Constant ◽  
Structural Changes ◽  
Structural Investigation ◽  
Energy Gap ◽  
Lattice Parameter ◽  
Metal Chalcogenides ◽  
Optical Energy Gap ◽  
Tin Telluride ◽  
Physical Quantities

Polycrystalline films of tin telluride were prepared by sintering technique. The structural investigation of the films with different thicknesses enables to determine lattice parameter, crystallite size and strain existing in the films. The XRD traces showed that strain was tensile in nature. The crystallite size increases with thickness while strain decreases. Higher the value of tensile strain, larger is the lattice constant. The optical energy gap shows a descending nature with increasing strain and so with the lattice constant. Such an attempt made to delve into interdependence of basic physical quantities helps to explore the properties of SnTe and utilize it as an alternative to heavy metal chalcogenides in various technological applications.  

Influence of Preparation Temperature on Performance of Ce1-xPrxO2 Ultrafine Powder Prepared by a Microemulsion Process

2008 ◽  
Vol 368-372 ◽  
pp. 784-786 ◽  
Author(s):  
Jun Yang ◽  
Zhen Feng Zhu ◽  
Jing Ping Li
Keyword(s):  
Crystallite Size ◽  
Calcination Temperature ◽  
Average Crystallite Size ◽  
Ultrafine Powder ◽  
Microemulsion System ◽  
Sem Images ◽  
Preparation Temperature ◽  
Annealing Conditions

A W/O microemulsion system composed of OP-emolsifier / water / cyclohexane / 1-Pentanol was adopted to prepare ultrafine Ce1-xPrxO2 powder via the reaction between the precipitants of cerium and praseodymium salt solved in the nano reactors. The influence of the annealing conditions on the preparation of Ce1-xPrxO2 powder was investigated. It was shown that, with the increase of calcination temperature from 400 °C to 800 °C, the average crystallite size of the particles increases from 9.5 nm to 25.8 nm. FE-SEM images showed that shape of the particles is layered and sheet-like.

The Effect of Different Methods to Pretreat Reed Pulp on the Crystallinity of Microcrystalline Cellulose

2014 ◽  
Vol 1056 ◽  
pp. 12-15 ◽  
Author(s):  
Wen Long Zhang ◽  
Wen Long Zhao ◽  
Ya Jie Dai
Keyword(s):  
Crystallite Size ◽  
Microcrystalline Cellulose ◽  
Average Crystallite Size ◽  
Comprehensive Analysis ◽  
Raw Material ◽  
Type I ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dimethyl Acetamide ◽  
Crystal Type

Reed Pulp was Raw Material that Pretreated by Four Methods {ultrasonic, Microwave, N, N-Dimethyl Acetamide (DMAc) and Tetrahydrofuran (THF)}. Reed Microcrystalline Cellulose (MCC) was Prepared by the Dilute Hydrochloric Acid Hydrolysis from Pretreated Reed Pulp. the Influences of Pretreatment Methods on Crystalline Type, Crystallinity and Crystallite Size of MCC were Investigated by X-Ray Diffraction (XRD). the Results Showed that the Crystallinity of MCC with Four Pretreatment Methods was 68.45%, 62.28%, 63.21% and 69.56%, Respectively. the Average Crystallite Size of MCC Prepared by Hydrolysis after Pretreated by Dmac was the Largest. whereas, the Crystal Type of MCC was Not Changed, it was still the Cellulose Type I. Comprehensive Analysis Indicated that the Effects of MCC Prepared by Hydrolysis after Pretreated by Ultrasonic were the Best.

scholarly journals Structural and Magnetic Properties of Co‒Mn Codoped ZnO Nanoparticles Obtained by Microwave Solvothermal Synthesis

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 410 ◽  
Author(s):  
Jacek Wojnarowicz ◽  
Myroslava Omelchenko ◽  
Jacek Szczytko ◽  
Tadeusz Chudoba ◽  
Stanisław Gierlotka ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystallite Size ◽  
Doping Level ◽  
Solvothermal Synthesis ◽  
Zinc Acetate Dihydrate ◽  
Average Particle Size ◽  
Average Crystallite Size ◽  
Average Particle ◽  
Acetate Tetrahydrate ◽  
Preparation Methods

Zinc oxide nanoparticles codoped with Co2+ and Mn2+ ions (Zn(1−x−y)MnxCoyO NPs) were obtained for the first time by microwave solvothermal synthesis. The nominal content of Co2+ and Mn2+ in Zn(1−x−y)MnxCoyO NPs was x = y = 0, 1, 5, 10 and 15 mol % (the amount of both ions was equal). The precursors were obtained by dissolving zinc acetate dihydrate, manganese (II) acetate tetrahydrate and cobalt (II) acetate tetrahydrate in ethylene glycol. The morphology, phase purity, lattice parameters, dopants content, skeleton density, specific surface area, average particle size, average crystallite size, crystallite size distribution and magnetic properties of NPs were determined. The real content of dopants was up to 25.0% for Mn2+ and 80.5% for Co2+ of the nominal content. The colour of the samples changed from white to dark olive green in line with the increasing doping level. Uniform spherical NPs with wurtzite structure were obtained. The average size of NPs decreased from 29 nm to 21 nm in line with the increase in the dopant content. Brillouin type paramagnetism and an antiferromagnetic interaction between the magnetic ions was found for all samples, except for that with 15 mol % doping level, where a small ferromagnetic contribution was found. A review of the preparation methods of Co2+ and Mn2+ codoped ZnO is presented.

Effect of reaction temperature on the average crystallite size of SexTe1−x alloys

1986 ◽  
Vol 1 (2) ◽  
pp. 234-236 ◽  
Author(s):  
Santokh S. Badesha ◽  
George T. Fekete ◽  
Ihor Tarnawskyj
Keyword(s):  
Crystallite Size ◽  
Small Particle ◽  
Chemical Method ◽  
Average Crystallite Size ◽  
Organic Media ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrophotographic Properties ◽  
Dark Decay ◽  
Chalcogenide Materials

Electrophotographic properties of chalcogenide materials are readily influenced by altering their composition and/or structure. Dark decay and cycle down of photoreceptors utilizing small particle generators are both directly proportional to average crystallite size (ACS). This paper describes a novel chemical method to control the ACS of Se, Te, and Sex Te1−x alloys. These chalcogenide materials are prepared as powders by the reduction or coreduction of SeIV and/or TeIV intermediates with hydrazine, in organic media. To control the ACS of precipitated chalcogens the reaction is carried out at the desired temperature. X-ray diffraction measurements are used to determine the ACS, homogeneity, and phase of these precipitated powders.

Oxygen bombardment effects on average crystallite size of sputter-deposited ZnO films

2008 ◽  
Vol 354 (17) ◽  
pp. 1926-1931 ◽  
Author(s):  
Mamoru Furuta ◽  
Takahiro Hiramatsu ◽  
Tokiyoshi Matsuda ◽  
Chaoyang Li ◽  
Hiroshi Furuta ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Average Crystallite Size ◽  
Zno Films ◽  
Sputter Deposited

scholarly journals Structural, electrical and magnetic behaviour of undoped and nickel doped nanocrystalline bismuth ferrite by solution combustion route

2015 ◽  
Vol 9 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Kakali Sarkar ◽  
Soumya Mukherjee ◽  
Siddhartha Mukherjee
Keyword(s):  
Crystallite Size ◽  
Bismuth Ferrite ◽  
Structural Phase ◽  
Average Crystallite Size ◽  
Magnetic Behaviour ◽  
Solution Combustion ◽  
Chemical Route ◽  
Structural Formation ◽  
Xrd Diffraction ◽  
The Matrix

Multiferroic bismuth ferrite (BFO) and Ni-doped bismuth ferrites, with perovskite structure, were synthesized by chemical route at the temperatures ranging from 500 to 600 ?C in controlled atmosphere. The structural phase analysis of materials was identified by XRD and crystallite size was calculated from the half width measurement of the well defined major XRD diffraction peak. Average crystallite size was calculated by applying Scherrer?s formula and found to have values in the range from 14 to 35 nm. FESEM was used to evaluate the morphology and structural formation of nanocrystallite grains, while EDX confirmed elemental composition including the presence of dopant in the matrix. Dielectric properties and effect of electric field on polarization behaviour were studied for both undoped and Ni-doped BFO. Doping shows a clear change in ferroelectric behaviour. Antiferromagnetic nature of bulk bismuth ferrite transforms to superparamagnetic strong ferroelectric nature for both undoped and nickel doped nanocrystalline bismuth ferrite due to its close dimension of crystallite size with magnetic domains leading to break-down of frustrated spin cycloidal moment. The superparamagnetism behaviour is more pronounced for the nickel doped BFO though magnetic saturation is slightly higher for the undoped nanocrystalline bismuth ferrite.

scholarly journals Comparison of structure and magnetic properties of Mn–Zn ferrite mechanochemically synthesized under argon and oxygen atmospheres

2015 ◽  
Vol 93 (10) ◽  
pp. 1168-1173 ◽  
Author(s):  
Mohamad Taghi Masoudi ◽  
Ali Saidi ◽  
Mansor Hashim ◽  
Abdollah Hajalilou
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Ball Milling ◽  
Spinel Phase ◽  
Average Crystallite Size ◽  
Argon Atmosphere ◽  
Diffusion Reaction ◽  
Particle Structure ◽  
Zn Ferrite ◽  
Milled Powders

Nanocrystalline Mn0.5Zn0.5Fe2O4 ferrite was successfully synthesized by ball milling a powder mixture of MnO, ZnO, and Fe2O3 under argon and oxygen atmospheres. The effects of the milling time, milling atmosphere, and annealing temperature on the milled powders were examined. X-ray diffractometry (XRD), scanning electron microscopy, and transmission electron microscopy were used to evaluate the powder particle structure. The XRD results indicated that after 20 h of ball milling the MnO–ZnO–Fe2O3 powder reacted with a solid-state diffusion reaction route producing Mn–Zn ferrite nanoparticles in the milled samples with both atmospheres. However, some Fe3O4 phase alongside Mn–Zn ferrite, both being spinel-phase, was detected for 40 h milled powders in the argon atmosphere. Those milled powders in the argon atmosphere had smaller crystallite size than the other ones. In the final stage of milling (40 h), the average crystallite size and lattice strain were 20 nm and 0.51%, respectively, ans 25 nm and 0.48% for milled samples in the argon and oxygen atmospheres, respectively. Vibrating sample magnetometer results indicate that the saturation magnetization and coercivity were 34 emu/g and 30 Oe, 18 emu/g and 70 Oe, respectively, for the 40 h milled samples in argon and oxygen, which were annealed at 800 °C for 2 h.

Effect of the ratio ZnO: ZrO2 on the photocatalytic ability of phenol degradation in ZnO-ZrO2 nanocompsite materials

2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Thao Pham Thi Minh ◽  
Huong Do Thi ◽  
Hai Le Thi
Keyword(s):  
Photocatalytic Activity ◽  
Crystallite Size ◽  
Phenol Degradation ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Ultrasonic Vibrations ◽  
Phenol Content ◽  
Photocatalytic Ability ◽  
Photocatalytic Reactions

The ZnO-ZrO2 nanocompsite materials in the molar ratio (1:0; 1:1; 1:2; 2:1; 3:4; 4:3; 0:1) were prepared by a two-stage precipitation method with ultrasonic vibrations. The obtained ZnO-ZrO2 materials were characterized by XRD, SEM, UV-vis. XRD data identified phase of the ZnO and phase of ZrO2 in all obtained samples. The average crystallite size of the samples was between 18 to 30 nm. As UV-Vis spectra, the band gap of ZnO-ZrO2 composite (ZZ34R) is 3,06eV. The photocatalytic reactions confirmed that the nanocomposite sample showed higher photocatalytic activity than the pure oxides samples for the degradation phenol under 100W incandescent lamp. Among the prepared samples, the best sample for photocatalytic degration of phenol is the ZZ34R which the molar ratio ZnO:ZrO2 = 3:4 with 23% remaining phenol content after 300 minutes. The photodegradation phenol of sample with ultrasonic vibrations is higher than the sample without ultrasonic vibrations. This indicates that the materials are capable of treating phenol in wastewater.

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