Some physical properties that affect the rate of diffusion of oxygen into silage

1983 ◽  
Vol 100 (3) ◽  
pp. 601-605 ◽  
Author(s):  
D. V. H. Rees ◽  
E. Audsley ◽  
M. A. Neale

SUMMARYExperiments are described which study the effect of density and chop length on the rate of diffusion of oxygen into silage and equations are presented which enable the rate of diffusion to be calculated under laboratory conditions. The concept of zero porosity is also discussed and methods of calculating the density at which it occurs are given. The effect of carbon dioxide on the rate of diffusion is also discussed.

Alloy Digest ◽  
1978 ◽  
Vol 27 (9) ◽  

Abstract UNIFLUX 70 is a continuous flux-cored welding electrode (wire) for welding in carbon dioxide shielding gas in the flat groove and horizontal fillet positions. It is used widely in shipbuilding and other fabricating industries to weld carbon steel and provides around 82,000 psi tensile strength and around 50 foot-pounds Charpy V-notch impact at 0 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: CS-74. Producer or source: Unicore Inc., United Nuclear Corporation.


2017 ◽  
Vol 733 ◽  
pp. 42-46
Author(s):  
Habiba Shehu ◽  
Edidiong Okon ◽  
Edward Gobina

Shuttle tankers are becoming more widely used in deep water installations as a means of transporting crude oil to storage plants and refineries. The emissions of hydrocarbon vapours arise mainly during loading and offloading operations. Experiments have been carried out on the use of polyurethane/zeolite membrane on an alumina support for the separation of methane from carbon dioxide and oxygen. The physical properties of the membrane were investigated by FTIR. Single gas permeation tests with methane, propane, oxygen and carbon dioxide at a temperature of 293 K and pressure ranging from 0.1 to 1.0 x 10-5 Pa were carried out. The molar flux of the gases through the membrane was in the range of 3 x 10-2 to 1 x 10-1 molm-2s-1. The highest separation factor of CH4/CO2 and CH4/O2 and CH4/C3H8 was determined to be 1.7, 1.7 and 1.6 respectively.


2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ivaná Đukic ◽  
Marija Ječmenica Dučić ◽  
Nikola Nikačević ◽  
Menka Petkovska

The goal of this work was to develop a 3D model of Electric Swing Adsorption pro- cess for carbon dioxide capture from effluent gasses from power plants. Detailed 3D model of the composite honeycomb monolithic adsorber was developed for a sin- gle monolith channel and can be used to simulate and represent different physical properties: velocity, concentration and temperature. The advantage of this model is the fact that all physical properties and results can be presented visually in the 3D domain. COMSOL Multiphysics software was used for solving partial differential equations and simulations of adsorption and electrothermal desorption processes. Some simulation results are presented in this work. The results obtained from 3D simulations will be used for the adsorber model reduction to the 1D model which will be used for modeling and optimization of the whole ESA cycle due to its sim- plicity and computational demands. Simulation and optimization runs based on the 1D model will be performed in g-Proms software.


Author(s):  
Yury Chernyak ◽  
Florence Henon

This chapter describes several aspects of the use of carbon dioxide as a solvent or cosolvent in coating applications. The primary impetus for using carbon dioxide for this purpose has been the alleviation of volatile emissions and liquid solvent wastes. However, the special physical properties of liquid and supercritical carbon dioxide may offer some processing advantages over conventional organic or aqueous solvents. Liquid carbon dioxide is quite compressible, and a reduction in temperature results not only in a reduction in the operating pressure, but also in a significant increase in the liquid density to values of approximately 0.9 g/cm3. At these high liquid densities, carbon dioxide exhibits improved solvent performance, but with much lower viscosities and interfacial tensions than aqueous or organic liquid solvents. Under supercritical conditions, carbon dioxide also exhibits high densities, low viscosities, and improved solvent power. Low viscosities and interfacial tensions tend to facilitate the transport of the solvents into any crevices or imperfections on the surface to be covered, and this might prove advantageous in the coating of patterned or etched surfaces. Since carbon dioxide dissolves and diffuses easily into many different polymers and organic liquids, it can also be used to reduce the viscosity of coating solutions. Whether in the liquid or the supercritical state, the temperature and pressure of the mixture can be used to control its physical properties in ways that are impossible to achieve with traditional solvents. These distinguishing features have raised the level of industrial interest in carbon dioxide as a solvent for coating applications, beyond those based solely on environmental concerns. In this chapter, we will discuss current applications and research on the use of CO2 as a solvent for coatings. The first section deals with spray coating from supercritical CO2. Subsequent sections deal with the use of liquid coatings, such as spin and free meniscus coatings, and impregnation coatings. Since the start of the 20th century (ca. 1907), atomization has been the basis for conventional spray coating applications (Muirhead, 1974). Typically, atomization is caused by high shear of the coating fluid in air, leading to droplet or particle formation.


Author(s):  
Chengjie Duan ◽  
Xiaoyong Yang ◽  
Jie Wang ◽  
Suyuan Yu

At present, power cycles used in HTGR are indirect steam Rankine cycle and helium Brayton cycle. Using water or helium as working fluid which transform thermal energy into mechanical energy for HTGR power cycle has many disadvantages. Steam cycle could choose steam system which is similar to conventional coal-fired power plant, but because of the limit of material and equipments, there is big temperature difference between the steam and the helium, that makes big loss of thermal power and lowers the cycle efficiency. Helium can reach a high temperature in HTGR Brayton cycle and it has good stability, but because of helium has big isentropic exponent and low density, it is difficult to compress and makes helium turbine has shorter blades and more stages than normal gas turbine. Carbon dioxide has good thermal stability and physical properties. To avoid the reaction of CO2 with graphite and canning of fuel element at high temperature, it should be used in an indirect cycle as second loop working fluid. CO2 has appropriate critical pressure and temperature (7.38MPa, 304.19K) and can choose three types of cycle: supercritical cycle, subcritical-pressure cycle and trans-critical-pressure cycle (CO2 sometimes works under supercritical pressure, some times under subcritical-pressure). Carbon dioxide cycle works in a high pressure, so it makes pressure loss lower. When CO2 works close to its critical point, its density become larger than other conditions, and not change very much, this permits to reduce compress work. The thermal physical properties of carbon dioxide are totally different from helium due to CO2 works as real gas in the cycle. That causes the calculation of CO2 thermal physical properties, heat transfer and power cycle efficiency become difficult and need to be iterated. A systematic comparison between helium and carbon dioxide as working fluid for HTGR has been carried out. An empirical equation had been selected to estimate the thermal physical properties of carbon dioxide. Three types of carbon dioxide power cycle have been analyzed and the thermal efficiency has been calculated. A detailed introduction to the basic calculation process of the CO2 cycle thermal efficiency had been presented in the paper.


2013 ◽  
Vol 649 ◽  
pp. 250-253 ◽  
Author(s):  
Petr Konečný ◽  
Jiří Teslík ◽  
Michal Hamala

Straw bales can be used as a relatively cheap and ecological building material for buildings. Design of straw buildings is currently based on empirical knowledge although it would be very helpful to have more information about material properties for designing and realization of straw bales houses. Article discuses load - deformation behavior of straw bales in laboratory conditions and evaluate the modulus of elasticity of local straw bales. Deformation characteristics of straw bales can be very useful for the design of straw buildings.


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