mylius thermometric technique. A review of a simple corrosion testing method of wide potentialities

Mylius' thermometric technique was developed in 1922 to assess the corrodability of aluminium alloys. Strips of the metals were made to react with known volumes of HCI solutions and the variation of the temperature of the system was followed with time. Following an induction period, the temperature rose to reach a maximum value. The corrodability of the metal was expressed in terms of the integral rate of temperature rise per minute. The Mylius test attracted little attention for almost 40 years. It was revived in the author's laboratory, where it was proposed as a rapid method for evaluating corrosion inhibitors. Since then, the technique underwent rapid development and wide expansion. It was applied to study the dissolution of zinc, iron, copper, nickel, tin and lead in a variety of attacking media. Equi-molar solutions of strong mineral acids do not attack metals to the same extent and this was attributed to anion adsorption on the metal surface. The abnormally high dissolution rate of metals in HNO[3] solutions was attributed to an auto-catalytic process involving the formation of HNO[2]. Substances known to destroy HNO[2] reduced corrosion. The Mylius thermometric technique was successfully applied to study the dissolution of a number of copper-base alloys, and its suitability for the determination of the thickness of zinc and tin coats on the surface of steel was proven. The method proved also to be of value in the study of galvanic [bimetallic] corrosion. The chemical oxidation of organic compounds is mostly an exothermic reaction. Here, too, the Mylius technique proved to be instrumental in elucidating the kinetics of the process. Only two examples are found in the literature describing this type of studies. The field is, however, wide open to examine other types of reaction. The dissolution of iron under conditions of the reaction Fe + 2Fe[3+] = 3Fe[2+] was studied in detail by the Mylius technique, and the results were confirmed potentiometrically and gravimetrically. The above reaction is both thermodynamically and kinetically more feasible than the discharge of protons from acid solutions. Mathematical treatment of the results allowed the conversion of the thermometric data into calorimetric ones, thus allowing thermodynamical computations to be carried out. Finally, suggestions are presented for the automation and computerization of the technique, which allow the simulation compensation of heat losses during measurements

Application of mylius thermometric technique to the study of galvanic corrosion

The Mylius thermometric technique, originally developed to examine general corrosion, is extended to cover galvanic corrosion. Pure zinc coupons dissolve in HCl solutions with the evolution of heat. The temperature-time curves exhibit a maximum whose value depends on acid concentration. Coupling the zinc coupons to copper causes increase in temperature maximum and in reaction number [R.N.]. The increase in R.N. varies linearly with the area of the copper cathode. A corresponding change in the rate of zinc dissolution is also registered. Both effects are explained on the basis of the catchment area principle

Biochemical impacts of some organophosphorus insecticides on cabbage plants

The side effect of certain organophosphorus pesticides on some biochemical aspects of cabbage plants was studied. At growth period of two months, the field grown plants were treated with the pesticides malathion, pirimiphos methyl and prothiofos. The investigated insecticides were used at the recommended doses and the spray was repeated three times at interval of one month. After each spray, randomized samples were taken after 0, one and two weeks of application and biochemically analyzed. The obtained results could be summarized as follows: 1-Chlorophyll analysis showed no significant variation after the first application. While continuous reduction was recorded after the second and third treatment. 2- Sugars and carbohydrates content were deplated in the treated cabbage leaves after the consequent application with the studied pesticidal chemicals. Malathion induced the maximum decline followed by prothiofos and pirimiphos-methyl. 3- Free amino acids exhibited different responses as far as the individual impact of the used chemicals was considered. Total proteins content showed an increase after the first application in response to both malathion and prothiofos. However, all the used pesticides decreased proteins content of the treated cabbage leaves after the second and third application. 4- Elemental analysis revealed that N was declined after the second and third spray in particular as a function of the sprayed materials. On the other hand P content was enhanced in the treated cabbage leaves in response to all the studied pesticides. K recorded no fixed trend after the different applications with respect to the influence of the individual chemicals

relation of mid-arm and chest circumferences to birth weight

Birth weight is a reliable and important indicator of the immediate and the later outcome of health care. It may be a problem in rural areas where home deliveries are prevalent and weight records are usually lacking. The aim of this work is to find out the correlation of mid-arm and chest circumferences [MAC and CC] to birth weight, which is a very simple and easy measurement. The results of 321 neonates, 180 term [> 37 ws] and 141 pre-term, [< 37 ws] showed a significant correlation between birth weight and MAC [0.8710] and with CC [0.8475] with no sex difference