Study on high-efficiency CO2 absorption by fresh cement paste

2020 ◽  
pp. 121364
Author(s):  
Lili Liu ◽  
Yongsheng Ji ◽  
Furong Gao ◽  
Li Zhang ◽  
Zhongzhe Zhang ◽  
...  
Keyword(s):  
Cement Paste ◽  
High Efficiency ◽  
Co2 Absorption

scholarly journals Study on the Effects of Ultrasonic Agitation on CO2 Adsorption Efficiency Improvement of Cement Paste

2021 ◽  
Vol 11 (15) ◽  
pp. 6877
Author(s):  
Lili Liu ◽  
Yongsheng Ji ◽  
Zhanguo Ma ◽  
Furong Gao ◽  
Zhishan Xu
Keyword(s):  
Cement Paste ◽  
High Efficiency ◽  
Co2 Adsorption ◽  
Ultrasonic Frequency ◽  
Co2 Absorption ◽  
Efficiency Improvement ◽  
Test Device ◽  
Vibration Technology ◽  
Internal Pore Structure ◽  
Internal Pore

To realize high-efficiency CO2 absorption by fresh cement paste, ultrasonic vibration technology is introduced into the CO2 absorption test device used in this study. Influences of ultrasonic frequency on the CO2 absorption rate (CO2 AR) and the ultimate absorption amount of fresh cement paste are analyzed. Furthermore, the influencing laws of the CO2 absorption amount (CO2 AA) on the fluidity, pore distribution, and mechanical properties of cement paste under ultrasonic vibrating agitation are analyzed by measuring the variations of the CO2 AA of cement paste. Results demonstrate that ultrasonic vibrating agitation not only can increase the CO2 AR and ultimate absorption amount of fresh cement paste, but also can optimize the internal pore structure of materials and compressive strength of cement-based materials.

scholarly journals Effect of fly ash on the strength of cement paste at early age

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 10-18
Author(s):  
Dung Trong Nguyen ◽  
Lam Van Tang ◽  
Hung Xuan Ngo ◽  
Phi Van Dang ◽  
Cuong Anh Ho ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Cement Paste ◽  
Power Plants ◽  
Building Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Early Age ◽  
Technical Specifications ◽  
Mineral Additives

In Vietnam, thermal power plants produce millions of tons of fly ash per year and cause a lot of problems for the environment. The re-use of fly ash as mineral additives in the production of building materials such as cement, concrete etc is a comprehensive solution that brings high socio-economic efficiency. However, to achieve high efficiency, the technical specifications index of fly ash needs to be studied and evaluated in detail because the content of added fly ash is very important for producing and manufacturing processes. This paper aims to study the influence of Formosa fly ash on the mechanical properties at the early age of cement paste. The mechanical properties of the samples which contain alternatively 10÷30% of fly ash was measured at the early ages (1, 3, and 7 days) by experimental methods. In addition, the microstructure analysis and differential thermal analysis methods have been used to interpret the obtained results.

Preparation of Cement Water Reducer of Modified Lignosulfonate

2010 ◽  
Vol 168-170 ◽  
pp. 541-544 ◽  
Author(s):  
Xiu Wen Wu ◽  
Heng Zhang
Keyword(s):  
Cement Paste ◽  
Reaction Temperature ◽  
High Efficiency ◽  
Oxidizing Agent ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Synthesis Conditions ◽  
Water Reduction ◽  
Optimum Synthesis ◽  
New Process

In this paper, the cement water reduction agent from modified lignosulfonate was synthesizd using a new process consisting of pre-oxidation, hydroxymethylation and sulfonation. The optimum synthesis conditions were identified: the oxidizing agent dosage is 15%, reaction temperature is 80-90oC, the dosage of formaldehyde is 30%, reaction temperature is about 95oC, pH is about 9.5. Fluidity of cement paste can be measured under the conditions of the addition of 0.25%, and the water-cement ratio is 0.4%. The results showed the modified lignosulfonate prepared under the above conditions had the better slushing performance. The fluidity of cement paste can reach 178 mm that is close to the high efficiency water reduction agent requirements.

Assessment of Power Generation Concepts on Oil Platforms in Conjunction With CO2 Removal

1994 ◽  
Author(s):  
Yngvil Bjerve ◽  
Olav Bolland
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Flow ◽  
High Efficiency ◽  
Co2 Concentration ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Co2 Absorption ◽  
Gas Combustion ◽  
Gas Turbine Exhaust

The introduction in 1991 of a CO2-tax on offshore combustion of natural gas has lead to an increased interest in both energy conservation and the possibility of separating CO2 from gas turbine exhaust. In this paper, several power generation concepts based on natural gas combustion by existing technology have been assessed in order to find the concept best suited for CO2 removal. An important factor when developing processes for offshore implementation is that space and weight are very expensive offshore. The suggested process consists of a power generation unit, a CO2 absorption unit and a CO2 compression unit. The power generation concepts have been evaluated in order to find the concept which combines the factors low exhaust gas flow, high CO2 concentration, high efficiency and low weight in the best possible manner. The result of the assessment is that a combined cycle with recycling of 40% of the exhaust volume back to the compressor inlet, is best suited for CO2 removal among the options studied.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

Interlayer confinement synthesis of Ir nanodots/dual carbon as an electrocatalyst for overall water splitting

2020 ◽  
Author(s):  
Yaru Li ◽  
Yu-Quan Zhu ◽  
Weili Xin ◽  
Song Hong ◽  
Xiaoying Zhao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Noble Metal ◽  
High Efficiency ◽  
Overall Water Splitting ◽  
Highly Dispersed

Rationally designing low-content and high-efficiency noble metal nanodots offers opportunities to enhance electrocatalytic performances for water splitting. However, the preparation of highly dispersed nanodots electrocatalysts remains a challenge. Herein, we...

Prime Mover of High Efficiency—I

1919 ◽  
Vol 88 (2282supp) ◽  
pp. 204-205
Author(s):  
Frank E. D. Acland
Keyword(s):  
High Efficiency ◽  
Prime Mover
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