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31.
Factors determining the permeation of eight alkylbenzene isomers of molecular weight 120.19 (three ethyl toluenes, three trimethylbenzenes, and two propl benzenes) were investigated for a lined nitrile industrial type glove using an ASTM-type cell, liquid collection, and gas chromatography/mass spectrometry. The initial permeation rate Pi correlated inversely with the logarithm of the lag time tl. The logarithm of the steady-state permeation rate Ps correlated inversely with the logarithm of the breakthrough time tb. Ps/Pi for a given compound correlated directly with Ps and with tl/tb. Pi depended directly on the logarithm of the entropy of fusion divided by the square of the refractive index and divided by the solubility parameter. The tb was inversely correlated to the logarithm of the water solubility. The logarithm of tl was most directly correlated to the entropy of vaporization. High Ps for 1,2,4-trimethylbenzene, m-ethyltoluene, and p-ethyl toluene was linked to a common structural similarity to 1,2,4-trimethylbenzene relative to the unhindered geometry of the methyl group in the ethyl side chain. The existence of optimum radii of gyration for enhanced Ps and for long tb suggested that the protective properties of nitrile followed discontinuous relationships rather than continuous ones and so are not explainable by correlative relationships of continuous functions. © 1996 John Wiley & Sons, Inc. 相似文献
32.
33.
Horizontal Dip‐Spin Casting of aqueous alumina‐polyvinylpyrrolidone suspensions with chopped fiber 下载免费PDF全文
Valerie Wiesner Manuel Acosta Lisa Rueschhoff Jeffrey Youngblood Rodney Trice 《International Journal of Applied Ceramic Technology》2017,14(6):1077-1087
A novel ceramic processing method, called Horizontal Dip Spin Casting (HDSC), enabled fabrication of tubular ceramic parts with an aligned chopped fiber phase. HDSC was demonstrated using highly loaded aqueous alumina suspensions with >50 vol.% solids loading and ≤5 vol.% water‐soluble polymer employed as a rheological modifier. Chopped carbon fibers were added to the suspensions to attain maximum loadings of 30 vol.%. During forming, cylindrical foam molds were dipped into the suspension while being rotated radially about the long axis. Simultaneously, a doctor blade was placed at a specified distance from the foam surface to facilitate the flow of the suspension to align the fiber and control the thickness of the material that accrued on the mold. Rheological study of alumina‐PVP suspensions with and without chopped carbon fiber showed that the suspensions exhibited a yield‐pseudoplastic flow behavior. The degree of alignment of the carbon fiber phase in the green bodies was characterized for various suspension formulations, carbon fiber contents and forming speeds. Stereological characterization of green body specimens confirmed the effectiveness of HDSC to attain the desired tubular geometry with considerable fiber alignment for a suspension composition containing ≤20 vol.% chopped fibers. 相似文献
34.
The effect of dietary TAG structure and fatty acid acyl TAG position on palmitic and linoleic acid metabolism was investigated
in four middle-aged male subjects. The study design consisted of feeding diets containing 61 g/d of native lard (NL) or randomized
lard (RL) for 28 d. Subjects then received an oral dose of either 1,3-tetradeuteriopalmitoyl-2-dideuteriolinoleoyl-rac-glycerol or a mixture of 1,3-dideuteriolinoleoyl-2-tetradeuteriopalmitoyl-rac-glycerol and 1,3-hexadeuteriopalmitoyl-2-tetradeuteriolinoleoyl-rac-glycerol. Methyl esters of plasma lipids isolated from blood samples drawn over a 2-d period were analyzed by GC-MS. Results
showed that absorption of the 2H-fatty acids (2H-FA) was not influenced by TAG position. The 2H-FA at the 2-acyl TAG position were 85±4.6% retained after absorption. Substantial migration of 2H-16∶0 (31.2±8.6%) from the sn-2 TAG position to the sn-1,3 position and 2H-18∶2n−6 (52.8±6.4%) from the sn-1,3 position to the sn-2 position of chylomicron TAG occurred after initial absorption and indicates the presence of a previously unrecognized isomerization
mechanism. Incorporation and turnover of the 2H-FA in chylomicron TAG, plasma TAG, and plasma cholesterol esters were not influenced by TAG acyl position. Accretion of
2H-16∶0 from the sn-2 TAG position in 1-acylphosphatidylcholine was 1.7 times higher than 2H-16∶0 from the sn-1,3 TAG positions. Acyl TAG position did not influence 2H-18∶2n−6 incorporation in PC. The concentration of 2H-18∶2n−6-derived 2H-20∶4n−6 in plasma PC from subjects fed, the RL diet was 1.5 times higher than for subjects fed the NL diet, and this result
suggests that diets containing 16∶0 located at the sn-2 TAG position may inhibit 20∶4n−6 synthesis. The overall conclusion is that selective rearrangement of chylomicron TAG structures
diminishes but does not totally eliminate the metabolic and physiological effects of dietary TAG structure. 相似文献
35.
矿山酸性含铜废水的处理研究 总被引:8,自引:0,他引:8
简述了矿山酸性含铜废水的来源、特点和危害及矿山酸性含铜废水的处理方法。在此基础上,选择离子交换法作为处理工艺,设计了实验室用离子交换处理装置,研究了过滤速度、pH值、原水Cu^2+浓度等因素对离子交换法处理酸性含铜废水效果的影响,确定了实验室条件下的合理工艺条件。并对某铜矿实际含铜废水进行了处理研究,取得了理想的处理效果,处理后废水可以达标排放。 相似文献
36.
Laura Frutos-Rincn Jos Antonio Gmez-Snchez Almudena Íigo-Portugus M. Carmen Acosta Juana Gallar 《International journal of molecular sciences》2022,23(6)
The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the lack of myelinated nerves (although it is extremely innervated), the tightly controlled hydration state, and the absence of blood and lymphatic vessels in healthy conditions, among others. The avascular, immune-privileged tissue of the cornea is an ideal model to study the interactions between its well-characterized and dense sensory nerves (easily accessible for both focal electrophysiological recording and morphological studies) and the low number of resident immune cell types, distinguished from those cells migrating from blood vessels. This paper presents an overview of the corneal structure and innervation, the resident dendritic cell (DC) subpopulations present in the cornea, their distribution in relation to corneal nerves, and their role in ocular inflammatory diseases. A mouse model in which sensory axons are constitutively labeled with tdTomato and DCs with green fluorescent protein (GFP) allows further analysis of the neuro-immune crosstalk under inflammatory and steady-state conditions of the eye. 相似文献
37.
38.
When a liquid droplet impacts on a solid surface, it recoils to the center of that surface after reaching its maximum spreading
diameter. The mechanism of droplet recoiling is not fully understood. To simulate this recoiling of a droplet, a particle
method is a good choice because it does not require grids for simulating fluid motions, and can easily handle a large deformation
of fluid. In this study, the coupled method of rigid body dynamics and the moving particle semi-implicit (MPS) method (Park
and Jeun, 2011) was used to calculate three-dimensional droplet impingement. Also, the previous surface tension model for
MPS (Nomura et al., 2001) was revised to get a more realistic surface tension force. A two-step calculation was performed.
In the first step, a MPS calculation was performed with particles that were considered to have no mass or volume. In the second
step, rigid body dynamics came into the calculation and considered the diameters of particles being slightly lesser than the
initial distance between particles. In this study, the calculated results were compared with the measured data (Kim and Chun,
2000) and the recoiling lengths of droplets for the various initial impingement speeds were estimated. 相似文献
39.
C. Magaña-Zavala M. E. Angeles-San Martin F. J. Rodríguez-Gómez D. R. Acosta R. Avila-Godoy A. López-Suárez 《Surface Engineering and Applied Electrochemistry》2010,46(2):115-119
Nickel thin films with regular configuration and similar thickness were deposited on steel AISI 1018 (UNSG 10180) by two different
techniques: magnetron sputtering and electrolytic process. The main aim of this work is to compare the surfaces deposited
films made by the two techniques using the scanning electronic microscopy and to identify their morphological differences
and imperfections. We evaluate the protective coatings properties when the films are in contact with an acid medium. We also
study the thin films coatings by the spectroscopy impedance technique. We obtain that the sputtering deposits present a homogeneous
thin film coating that is better than the one obtained by the electrolytic technique. It is expected that the thin film coatings
made in this work can protect the steel against corrosion when it is in contact with an acid environment. 相似文献
40.
The fundamentals of barriers to reverse engineering and their implementation into mechanical components 总被引:1,自引:0,他引:1
Shane K. Curtis Stephen P. Harston Christopher A. Mattson 《Research in Engineering Design》2011,22(4):245-261
Reverse engineering is a common design strategy in industry. It is a term that has come to encompass a large array of engineering
and design activities in the literature; however, in its basic form, reverse engineering is simply the process of extracting
information about a product from the product itself. Depending on its use, it may or may not be advantageous to utilize a
reverse engineering strategy. As with any rational decision, reverse engineering is only favorable when the benefits from
its use outweigh the investment. Therefore, a general understanding of the principles that increase the difficulty or investment
required to reverse engineer mechanical products would be helpful for everyone affected by reverse engineering activities.
In this paper, we articulate and explore these fundamental principles after reviewing examples from the literature and from
our own experience. We then use the principles as a basis for the development of a methodology to build barriers to reverse
engineering into new products. 相似文献