Picosecond Transient Reflectance Measurements of Crystallization In Pure Metals

1985 ◽  
Vol 51 ◽  
Author(s):  
C.A. MacDonald ◽  
A.M. Malvezzi ◽  
F. Spaepen
Keyword(s):  
Optical Property ◽  
Copper Films ◽  
Concentration Profiles ◽  
Rapid Crystallization ◽  
Before And After ◽  
Pure Metals ◽  
Property Changes ◽  
Kinetics Of ◽  
Reflectance Measurements

ABSTRACTThe kinetics of rapid crystallization in metals is investigated by measuring transient optical property changes in laser irradiated gold and copper films in the picosecond and nanosecond regimes. Melt thresholds are determined by examining concentration profiles of multi-layered films before and after irradiation.

scholarly journals Testing Sorption Properties of Halloysite by Means of the Laser Interferometry Method

2015 ◽  
Vol 37 (1) ◽  
pp. 43-47
Author(s):  
Sławomir Wąsik ◽  
Michał Arabski ◽  
Karolina Maciejec ◽  
Grażyna Suchanek ◽  
Anna Świercz
Keyword(s):  
Concentration Field ◽  
Laser Interferometry ◽  
Membrane System ◽  
Absorption Capacity ◽  
Sorption Properties ◽  
Concentration Profiles ◽  
Adsorbed Substance ◽  
Interferometry Method ◽  
Set Up ◽  
Kinetics Of

The objective of the present study has been to test the laser interferometry method in terms of its usability for investigating sorption properties of minerals. This method was used to test the absorption capacity of halloysite with reference to glucose, which is often found in industrial wastewater and whose excess can disturb the environmental eco-balance. The sorption capacity of halloysite was thus determined indirectly, basing on the comparison of concentration profiles as well as time characteristics of glucose quantities released from the control solution and from the solution incubated with a halloysite adsorbent. An analysis of glucose diffusion was conducted in a two-chamber membrane system. On the basis of the obtained concentration profiles, the evolution of the concentration field was determined; so were the removal efficiency (%) and the amount of glucose adsorbed at equilibrium (qe, mg/g). The obtained results confirm good sorption properties of halloysite with respect to the investigated substance as well as usability of the method for this kind of investigations. The presented tests suggest that the measurement set-up can be optimised in such as way that visual rendering and testing the kinetics of the adsorbed substance direct release from the studied material become possible.

STUDY OF THE KINETICS OF DRYING BREWER’S SPENT GRAIN

2020 ◽  
Author(s):  
Т.Г. КОРОТКОВА ◽  
А.С. ДАНИЛЬЧЕНКО ◽  
Н.Ю. ИСТОШИНА
Keyword(s):  
Matter Content ◽  
Dry Matter Content ◽  
Drying Time ◽  
Brewer’S Spent Grain ◽  
Average Value ◽  
Free Moisture ◽  
Before And After ◽  
Spent Grain ◽  
Kinetics Of ◽  
Two Temperature

Исследована кинетика сушки сырой пивной дробины – вторичного продукта ООО «Белореченский пивоваренный завод» (Россия, Краснодарский край). Сушка проведена в двух температурных режимах – 60 и 55°С. Скорость сушильного агента при вынужденной конвекции составляла 4,5 м/с. Содержание сухого вещества определено по ГОСТ 31640–2012 в лабораторных условиях и составило 12,9%. Измерение убыли массы при сушке проведено с интервалом 5 мин. Общее время сушки навески пивной дробины в количестве 50 г – 420 мин при режиме 50°С, 360 мин – при 60°С. Среднее значение конечной влажности пивной дробины составило 11,85%. Построены кривые сушки и скорости сушки. Скорость сушки при удалении свободной влаги в первом периоде сушки, мин–1: при 60°С – 3,5, при 55°С – 3,0. Установлено, что содержание связанной влаги составляет в среднем 57% от массы влаги в навеске пивной дробины, свободной влаги – 43%. Анализ структуры навески пивной дробины под микроскопом до сушки и после нее подтвердил факт, что в исследованном материале количество связанной влаги больше, чем свободной. Наличие частиц размером 5–7 мм свидетельствует о значительном количестве клеточной влаги в неразрушенных капиллярах. Дальнейшее совершенствование технологии переработки пивной дробины должно быть направлено на разрушение клеточной структуры материала после его механического обезвоживания. The kinetics of drying of the crude brewer’s spent grain – a secondary product of LLC «Belorechensky brewery» (Russian Federation, Krasnodarregion) has been studied. Drying is carried out in two temperature modes – 60 and 55°C. The speed of the drying agent under forced convection was 4,5 m/s. The dry matter content was determined according to GOST 31640–2012 in laboratory conditions and was 12,9%. Measurement of mass loss during drying was performed at an interval of 5 min. The total drying time of the brewer’s spent grain sample in the amount of 50 gis 420 min at 50°C, 360 min – at 60°C. The average value of the final moisture content of brewer’s spent grain made up 11,85%. Curves of drying and drying speed are constructed. Drying speed when removing free moisture in the first drying period, min–1: at 60°C – 3,5, at 55°C – 3,0. It was found that the content on average of bound moisture is 57% of the mass of moisture in brewer’s spent grain, free moisture – 43%. Analysis of the structure sample of brewer’s spent grain a microscope before and after drying confirmed the fact that the amount of bound moisture in the studied material is greater than the amount of free moisture. The presence of particles of 5–7 mm in size indicates a significant amount of cellular moisture in undisturbed capillaries. Further improvement of the technology for processing brewer’s spent grain should be aimed at destroying the cellular structure of the material after its mechanical dehydration.

Studies on the Property Changes of Environmental Degradation Mulching Film and Polyethylene Mulching Film in Water Environment

2012 ◽  
Vol 268-270 ◽  
pp. 241-244
Author(s):  
Bin Bin Zhao ◽  
Xue Gang Luo ◽  
Xiao Yan Lin ◽  
Hong Ping Zhang
Keyword(s):  
Environmental Degradation ◽  
Water Environment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyethylene Mulching ◽  
Before And After ◽  
Diffraction Peaks ◽  
Property Changes ◽  
Mulching Film

This paper studied the property changes of environmental degradation mulching film and polyethylene mulching film in water environment. The XRD (X-ray diffraction) cures showed that the diffraction angles of environmental degradation mulching film were not changed but intensities and area of diffraction peaks increased after immersion for 60 days; while the diffraction angles and area of diffraction peaks of polyethylene mulching film were same before and after immersion. Cracks and holes appeared in surface of environmental degradation mulching film, but it was still smooth and uniform for the polyethylene mulching film after immersion.

scholarly journals Enhanced removal of hexavalent chromium by different acid-modified biochar derived from corn straw: behavior and mechanism

2020 ◽  
Vol 81 (10) ◽  
pp. 2270-2280
Author(s):  
Yonggang Xu ◽  
Tianxia Bai ◽  
Yubo Yan ◽  
Yunfeng Zhao ◽  
Ling Yuan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrogen Ion ◽  
Corn Straw ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
Modified Biochar ◽  
Before And After ◽  
Pseudo Second Order ◽  
Kinetics Of

Abstract It is of great significance to remove Cr(VI) from water as a result of its high toxicity. Biochar from corn straw was modified by different acids (HNO3, H2SO4 and H3PO4) to remove Cr(VI) from aqueous solution. To estimate the removal mechanisms of Cr(VI) by the acid-modified biochars, batch experiments were performed in the light of contact time, Cr(VI) concentration, and pH, and the characteristics of acid-modified biochars before and after Cr(VI) adsorption were investigated by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of Cr(VI) by acid-modified biochars were consistent with the pseudo-second-order model, and the adsorption isotherm obeyed the Freundlich model. Furthermore, the acid- modified biochars could supply more oxygen-containing functional groups (-COOH and -OH) as electron donor (e−) and hydrogen ion (H+) to enhance the reduction of Cr(VI) to Cr(III), resulting in enhanced removal of Cr(VI). HNO3-modified biochar exhibited the highest removal efficiency of Cr(VI). In general, the acid modifition of biochar was an effective method to increase the removal of Cr(VI).

scholarly journals Graphene-Supported Thin Metal Films for Nanophotonics and Optoelectronics

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1058 ◽  
Author(s):  
Dmitry I. Yakubovsky ◽  
Yury V. Stebunov ◽  
Roman V. Kirtaev ◽  
Kirill V. Voronin ◽  
Artem A. Voronov ◽  
...  
Keyword(s):  
Metal Films ◽  
Electron Beam Evaporation ◽  
Hybrid Nanostructures ◽  
Monolayer Graphene ◽  
Gold Films ◽  
Copper Films ◽  
Optical Losses ◽  
Potential Applications ◽  
Output Characteristics ◽  
Kinetics Of

Graphene-metal hybrid nanostructures have attracted considerable attention due to their potential applications in nanophotonics and optoelectronics. The output characteristics of devices based on such nanostructures largely depend on the properties of the metals. Here, we study the optical, electrical and structural properties of continuous thin gold and copper films grown by electron beam evaporation on monolayer graphene transferred onto silicon dioxide substrates. We find that the presence of graphene has a significant effect on optical losses and electrical resistance, both for thin gold and copper films. Furthermore, the growth kinetics of gold and copper films vary greatly; in particular, we found here a significant dependence of the properties of thin copper films on the deposition rate, unlike gold films. Our work provides new data on the optical properties of gold and copper, which should be considered in modeling and designing devices with graphene-metal nanolayers.

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