Modeling the rate of corrosion of carbon steel using activated diethanolamine solutions for CO2 absorption

A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide (CO₂). Piperazine (PZ) is used as the activator in diethanolamine (DEA) aqueous solutions. The developed model for corrosion takes into consideration the effect of fluid flow, transfer of charge and diffusion of oxidizing agents and operating parameters like temperature, activator concentration, CO₂ loading and pH. The study consists of two major models: Vapor-liquid Equilibrium (VLE) model and electrochemical corrosion model. The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution. The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal. An increase in concentration of activator, increases the rate of corrosion of carbon steel in mixtures of activated DEA.     

Performance Evaluation for Transform Coding Using a Nonseparable Covariance Model

Intraframe transform coding of pictures for the case of a nonseparable covariance model is considered. Performances of the Walsh-Hadamard, discrete cosine and Karhunen-Loeve transforms are compared based on the compaction of signal energy in the transform components, and, the degree of decorrelation of the data. The results demonstrate that the performances of the discrete cosine and Karhunen-Loéve transforms compare closely, as is the case with a separable covariance model. The corresponding performance of the Walsh-Hadamard transform is inferior.     

Personality characteristics and socioeconomic variables.

Conducted a study of 125 male and 128 female heads of household in Ontario, Canada in order to determine the relationship between scores on 11 personality scales (from the Personality Research Form, MPI, and CPI) and socioeconomic status and age. Results reveal a number of significant correlations of male Ss with age, household income, occupational status, and educational level. The Dominance scale showed the highest correlation with male Ss' income and educational level. Male non-high school graduates' scores on Harmavoidance and Change scales varied markedly with age level. Although the above findings with regard to age and education applied to both male and female Ss, correlations with male Ss were considerably higher than those with female Ss. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aktivit?t und subcellul?re Verteilung einiger Mitochondrien-Enzyme im Skeletmuskel. II. Ver?nderungen im Rindermuskel post mortem

Zusammenfassung Proben desLongissimus-dorsi-Muskels des Rindes wurden bis zu 15 Tage nach dem. Schlachten bei 4° C gelagert. Die Änderung der extrahierbaren absoluten und spezifischen Aktivität der Mitochondrien-Enzyme Aconitase (AC), Fumarase (FU), Glutamatdehydrogenase (GLDH), Malatdehydrogenase (MDH) and Succinodehydrogenase (SDH) während der Lagerung wurde studiert. Es wurde ferner der Einfluß der Lagerung auf die Aktivität der SDH im nicht zentrifugierten Muskelhomogenat ermittelt. Während die Gesamtaktivität von FU und ACpost mortem abnahm, blieb die Aktivität von SDH und MDH nahezu unverändert. Die extrahierbare GLDH-Aktivität wies im Zustand desRigor mortis ein Minimum auf.Durch Bestimmung der Enzymaktivitäten im Preßsaft des unzerkleinerten Gewebes wurde die Änderung der subcellulären Verteilung der Mitochondrien-Enzymepost mortem verfolgt. AC, MDH und SDH wurden während der Lagerung des Muskelspost mortem nicht aus ihrer Bindung an die Mitochondrien freigesetzt. FU wurde nach Eintritt desRigor mortis in geringem Maße freigesetzt. GLDH trat innerhalb von 24 Stdpost mortem in erheblichem Umfang aus ihrer Bindung an Mitochondrien in das Sarkoplasma über.Die Resultate lassen den Schluß zu, daß die Mitochondrien des Rindermuskels im Verlauf desRigor mortis eine Schädigung erfahren, die zu einem partiellen Austritt der Matrix in das Sarkoplasma ohne wesentliche Desintegration der Mitochondrienmembranen führt. Die Möglichkeit einer Öffnung der intramitochondrialen Räume durch Quellung der Mitochondrien als Folge des glykolytisch bedingten pH-Abfalls wird diskutiert.

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Activity and subcellular distribution of some mitochondria) enzymes in skeletal muscle. II. Post-mortem changes in bovine muscle

Summary Samples of bovineM. longissimus dorsi were stored for up to 15 days post mortemat at 4° C. The changes in the extractable absolute and specific activities of the mitochondria) enzymes aconitase (AC), fumarase (FU), glutamic dehydrogenase (GLDH), malate dehydrogenase (MDH) and succinic dehydrogenase (SDH) were determined. The influence of storage on the activity of SDH in the muscle homogenate was also studied. There was a decrease in the total activity of AC and FU post mortem, but no remarkable changes in the activity of SDH and MDH. The GLDH activity showed a minimum at the time of rigor mortis.The changes in the subcellular distribution of the mitochondria) enzymes post mortem were determined by studying the enzyme activities in the press juice of the intact muscle tissue. AC, MDH and SDH were not released from mitochondria) structures during storage of muscle. There was a small release of FU after development of rigor mortis. However, a great part of GLDH was released from the mitochondria into the sarcoplasma within 24 h post mortem.The results show that the mitochondria of bovine muscle undergo a certain damage during development of rigor mortis which results in a partial efflux of the mitochondria) matrix into the sarcoplasma without a remarkable desintegration of the mitochondria) membranes. The possibility of an opening of the intramitochondrial spaces by swelling of mitochondria caused by the decrease of pH post mortem is discussed.

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Stipendiat der Alexander-von-Humboldt-Stiftung. Jetzige Adresse: University of Assiut, Faculty of Agriculture, Assiut, VAR.     

Two-port subnetworks of exponential distributed parameter Z-Y-KZ and Y-Z-KY micro-circuits with similar transfer functions

This paper shows that one may find a two-port subnetwork of the exponential distributed parameter (DP) Z-Y-KZ micro-circuit whose open-circuit voltage and short-circuit current ratio-transfer functions are exactly the same as those of another two-port subnetwork of the exponential (DP) Y-Z-KY micro-circuit. There are in total 28 such unique non-redundant two-port subnetworks of the exponential Z-Y-KZ structure which have their counterparts produced by the exponential Y-Z-KY micro-circuit. The results are given in a table. This information is intended to eliminate the duplicacy of time-consuming labour involved in the analyses of these subnetworks obtainable from the exponential Z-Y-KZ and Y-Z-KY structures in view of recent interest in the performance characteristics of such subnetworks.     

The epidemiology of fatal motor vehicle accidents in Kuwait

The main objectives of this study are to present data on fatal motor vehicle accidents in Kuwait with a view to find out the principal epidemiological features, establish a baseline for future evaluation, use international death rates to compare Kuwait with other countries and offer specific recommendations as to how the risks involved can be reduced. The epidemiology of all fatal accidents which had occurred in Kuwait between 1 January 1977 and 31 December 1978 are analysed. This two-year series, which includes 726 accidents and represents 1.7% of all types of accidents, resulted in 803 deaths (7.3% of the national deaths toll) and 1175 injuries. The death rates per hundred million vehicle kilometers of travel, per 100,000 registered motor vehicles and per 100,000 resident population in 1978 were about 8.5, 84.8 and 31.7 respectively. These figures reveal significantly higher rates than in some industrialized countries, thus ranking motor vehicle accidents among the four leading causes of death and probably as the commonest single cause of death in Kuwait. The study shows that children under the age of 15 yr contributed 26.2% of all motor vehicle fatalities. 40.9% of pedestrian deaths (55.2% of the series), 25% of pedal-cyclist deaths, 6.3% of motorcyclist deaths and 1.2% of driver deaths. It also confirms the importance of the motor vehicle-pedestrian type of accident (58.3%) and the over-representation of buses, trucks and motorcycles with respect to involvement in fatal accidents as compared to their relative ratios of registered vehicles. The principal recommendations call for the formation of a National Council for Road Safety, the establishment of intensive roadside care, traffic education of road users and at risk groups, improvement of the environment and the firm enforcement of the law to curb the toll of this killer disease in a traditional country undergoing rapid modernization like Kuwait.     

Checking Timed Büchi Automata Emptiness Efficiently

This paper presents an on-the-fly and symbolic technique for efficiently checking timed automata emptiness. It is symbolic because it uses the simulation graph (instead of the region graph). It is on-the-fly because the simulation graph is generated during the test for emptiness. We have implemented a verification tool called Profounder based on this technique. To our knowledge, Profounder is the only available tool for checking emptiness of timed Büchi automata. To illustrate the practical interest of our approach, we show the performances of the tool on a non-trivial case study.     

Dietary factors and the regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase: implications for breast cancer and development

A role for mevalonate in cancer development has long been suggested by findings that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity is elevated in malignant cells. Increased synthesis mevalonate and mevalonate-derived nonsterol isoprenoids supports increased cell proliferation through the activation of growth-regulatory proteins and oncoproteins, and by promoting DNA synthesis. We have recently shown that mevalonate promotes the growth of human breast cancer cells both in culture and as tumors grown in nude mice. Inhibition mevalonate synthesis, therefore, may be an effective strategy to impair the growth of malignant breast cells. Several dietary compounds with known anti-cancer effects are also reported to inhibit HMG-CoA reductase activity. Here, we review evidence suggesting that inhibition of mevalonate synthesis may mediate the protective effects of cholesterol, plant isoprenoids, genistein, and long-chain n-3 polyunsaturated fatty acids (PUFAs) on experimental breast cancer.     

Electromechanical properties of high coupling single crystals under large electric drive and uniaxial compression

This work investigates the 33-mode electromechanical response of relaxor-ferroelectric lead magnesium niobate-lead titanate (PMN-PT) single crystals when driven with large fields approximately 0.4 MV/m under a combined direct current (DC) field and mechanical bias similar to those used in the design of sound projectors. It demonstrates that the remarkable small signal length extensional coupling (k33 > 0.90) and other electromechanical properties of morphotropic PMN-PT single crystals prevail under large drive. The observed k33 roll-off at 42 MPa compressive stress is analyzed in terms of the recent structural data and the high-order Devonshire theory of possible ferroelectric-ferroelectric transition trajectories.