Thermodynamic analysis of the phase transition of polyethylene under high pressure

Mechanism of emergence of high pressure phase of polyethylene is analysed on the thermodynamic stand point: The change in free energy due to pressure increase is calculated for each phase on the basis of the experimental data. The transition temperature and melting point under the increased pressures are estimated and the results obtained are consistent with the observed values.     

A high‐speed‐execution method for a program written in factory‐automation‐cell control language

A new programming method called Cell Control Language (CCL) for factory‐automation systems has been developed. In CCL programming, an action sequence of each functional unit in each operation mode is first described as a net module. This net module is a subclass of Petri nets, and this subclass is equivalent to a state‐transition diagram (a conventional design method). Several net modules are merged and translated into an internal code program, which is executed in a cell controller. To improve the ability of the controller to respond to state changes, we developed two new methods based on CCL. One is that for efficiently describing a CCL program, which needs a quick response to state changes, and the other is that for executing the program in a short cycle. The execution method was applied to an actual cell controller, which confirmed that it can improve the ability to respond to state changes without reducing the total control performance. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 34–42, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10167     

Sulfated bile acid in urine of patients with hepatobiliary diseases

The presence of sulfated bile acid in urine of patients with hepatobiliary diseases was recognized by using an Amberlite XAD-2 column for extraction of bile acid and a Sephadex LH-20 column for separation of sulfated (sulfate of either taurine or glycine conjugate) and nonsulfated bile acid (taurine and glycine conjugate). Sulfated and nonsulfated bile acid, obtained after a Sephadex LH-20 column of urinary extract of the patient with acute hepatitis, was identified by thin layer chromatography. Sulfated bile acid showed a spot with different Rf value from that of taurine-conjugated, glycine-conjugated and free bile acid, and solvolysis of sulfated bile acid resulted in a compound with the same Rf value as glycodihydroxycholanoic acid. A large amount of bile acid sulfate was found in urine of patients with hepatobiliary diseases. The sulfated bile acid in these urine samples occupied from 57.1 to 93.3% of total bile acid, and consisted of both di-and trihydroxycholanoic acid (major part, chenodeoxycholic acid). As no solvolysis was carried out in previous works, bile acid sulfate in urine, as described in this paper, was not determined at all.     

Carbonization of an anthracene oil extract of Akabira (Japan) coal

The carbonization of a non-hydrogenated extract (STC) from a low-rank coal (C, 83 wt%) of high fluidity was studied as single carbonizations and as co-carbonizations with additives, an objective being the production of needle-coke. The coke from STC had an optical texture of fine-grained mozaics; however, fractionation followed by co-carbonizations were effective in modifying carbonization properties. The lighter fraction of STC could give a coke with flow texture but in reduced yield. The addition of hydrogenated Ashland A240 pitch (HA240) in a quantity as low as 20% could effectively modify the carbonization properties of STC. A novel co-carbonization, in which an additive such as dihydroanthracene is recovered at the latter stage of the carbonization in the dehydrogenated form, was found to be effective also, although a relatively large amount of the additive was required. Among the non-hydrogenated additives, Ashland A240 pitch was the most effective in modifying the STC. The cocarbonization of fractionated STC reduced the quantity of additive required while maintaining a reasonable coke yield. Some practical aspects for the production of needle-coke from STC are discussed.     

Analysis of the Effect of Buffer Storage Capacity in Transfer Line Systems

The purpose of this paper is to gain insight into the effect of buffer storage capacity in two-stage transfer lines by presenting results of a theoretical study of the problem. A Markov model of the problem is proposed to analyze the effect of in-process inventory banks on the production rate and the mean number of units in the storage area. Based on the model developed, the effect of internal storage is evaluated, and the question of how much buffer storage capacity should be provided is discussed.     

Carbonization of aromatic hydrocarbons—IV: Reaction path of carbonization catalyzed by alkali metals

The carbonization path of aromatic hydrocarbons catalyzed by alkali metals has been investigated to elucidate how aromatic hydrocarbons were converted into the isotropic coke, compared to the same reaction catalyzed by aluminum chloride which gave the anisotropic needle-like coke. Attempts were made to identify the intermediate products by means of elemental analyses, NMR, and mass spectroscopy, and the process was followed by the analysis of evolved gases. Effects of the catalyst migration at the intermediate step of carbonization on the properties of produced coke were also investigated to know when the destiny of the coke was determined. These results indicate that the isotropic nature of the coke obtained from the aromatic hydrocarbons with alkali metals is due to the extensive dehydrogenation of the intermediate at the early stage of carbonization at ca. 250°C. The dehydrogenation may raise the melting point of the carbonizing material. Other factors influencing the nature of the coke are considered to be unimportant in the present case.     

Desulfurization of petroleum residues and their carbonization properties

The desulfurization of petroleum residues of high sulfur content was carried out using three kinds of Lewis acids under a nitrogen flow of atmospheric pressure at 150–330°C. Considerable amounts of sulfur were eliminated from the residue as hydrogen sulfide with the aid of aluminum chloride at 150°C or higher temperatures. Ferric or zinc chloride was found also to eliminate sulfur from the residue in the form of the corresponding metal sulfides at 330°C without the evolution of hydrogen sulfide.Effects of such desulfurization on the coking properties were observed by means of optical microscopy and X-ray diffraction. Although the original residues gave cokes with a mosaic arrangement of anisotropic domains, benzene-soluble fractions of the desulfurized residue gave a graphitizable needle coke. The desulfurized residues were further analyzed by chemical techniques to study the structural change brought about by acidic desulfurization. This kind of desulfurization was revealed to be carried out without decreasing the aromaticity of the residue, being different from the hydrodesulfurization with cobalt-molybdena catalysts.     

2 Mb SPRAM (SPin-Transfer Torque RAM) With Bit-by-Bit Bi-Directional Current Write and Parallelizing-Direction Current Read

A 1.8 V 2 Mb SPin-transfer torque RAM (SPRAM) chip using a 0.2 mum logic process with an MgO tunneling barrier cell demonstrates the circuit technologies for potential low-power nonvolatile RAM, or universal memory. This chip features an array scheme with bit-by-bit bi-directional current writing to achieve proper spin-transfer torque writing of 100 ns, and parallelizing-direction current reading with a low-voltage bit-line for preventing read disturbances that lead to 40 ns access time.     

Synthesis of chiral side-chain liquid crystalline polyacetylenes bearing succinic acid spacer

A chiral acetylene monomer having a cholesteryl group (PSCh) and novel three types of chiral acetylene monomers having a o-substituted tyrosine methyl ester (PSMY-Rs: –COC₆H₅=PSMY-Bz; –COC₆H₄CN=PSMY-BzCN; –COC₁₂H₉=PSMY-PhBz) as a pendant group were synthesized from 4-oxo-4-(prop-2-ynyloxy)butanoic acid (PS), and polymerized with the rhodium-catalyzed system. Structures and properties of the monomers and the resulting polymers were characterized and evaluated by NMR, IR, GPC, and DSC. In addition, these optical properties were investigated by polarimetric detector and circular dichroism (CD) analyses.