Weight losses

All results are reported in Tables 8.9. and 8.10, where weight losses are reported and compared with the maximum accepted practical value, which is 0.244 kg/m (0.05 Ib/ft ) for each single acidizing operation calculated corrosion rates are also reported. 

Although data reported by suppliers on technical information brochures, low alloy steels, exposed to inhibited solutions, exhibited in laboratory test conditions severe corrosion rates, higher than maximum allowed. Most likely this is primarily due to the high temperature and relatively long exposure time. Of the two corrosion inhibitors tested, that designated B showed a better effectiveness in all experimental conditions. 

Relative volatihty of plasticizers can be determined by this method. Plasticizers are placed in a circulating air oven on a rotating table. The oven is set to either 105 or 155°C and the samples are cooled and weighed after 2,4, and 24 hours. Weight loss is calculated and reported in percent of plasticizer loss between time intervals, as a loss relative to rmit area of ejqtosed surface, or as an average volatility rate (amount lost per surface area and time). Results depend on control of temperatore and air flow. It is crrstomary to compare different plasticizers in the same experiment to avoid interference of experimental conditions. 

A direct activated carbon method is specified for determination of volatiles loss of calendered, extruded, and cast films and sheeting. The standard also contains a graph of maximum volatile loss vs. film thickness. 

Volatile matter in trictesyl phosphate is determined as the amount of weight loss after 3 h at 105°C.  

ASTM standard is similar to ISO standard but it is not its technical equivalent. The main differences include samples thickness (0.25 mm in ASTM and 1 mm in ISO), activated carbon size (1.4 mm in ASTM and 4 to 6 mm in ISO), gauze apertures (0.595 mm in ASTM and 0.5 mm in ISO), and container sizes. Different activated carbon grades give different results. According to ASTM standard percent of weight loss is an inverse function of sample thickness. 

Non-volatile matter is determined by placing material on a sample dish in an oven at an agreed temperature and time. ° For plasticized materials it is assumed that the residue normally contains plasticizers. 

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Compound Feedstock, weight % Alkylate, weight % LPG, weight % Losses, weight %... 

A 38.63-mg sample of potassium ozonide, KO3, was heated to 70 °C for 1 h, undergoing a weight loss of 7.10 mg. Write a balanced chemical reaction describing this decomposition reaction. A 29.6-mg sample of impure KO3 experiences a 4.86-mg weight loss when treated under similar condition. What is the %w/w KO3 in the sample ... 

Method 8.2 describes a procedure for determining Si in ores and alloys. In this analysis a weight loss of 0.21 g corresponds to 0.1 g of Si. Show that this relationship is correct. 

The simplest nutritional role of fats in the diet is that of energy supply. There are differences between members of the same class of food materials, but the accepted convention attributes a value of 9 kcal (37.7 kJ) of energy per gram of fat, and 4 kcal (16.7 kJ) of energy per gram of all carbohydrates and proteins. This is a serious consideration in generating weight loss diets. 

Before the fibers can be spun into yams, a certain amount of preparation is necessary for cleaning and removal of undesirable accessory materials such as fat, wax, gum, or pulp. The weighting of sUk is a process to counter the weight loss resulting from degumming the fibers using heavy metal salts of tin or bismuth. This process affects the durabUity and long term preservation. 

The thermodynamic properties of Tefzel 200 and 280 are shown in Table 2 the annual rate of loss of weight with thermal aging for Tefzel 200 ranges from 0.0006 g/g at 135°C to 0.006 g/g at 180°C after an initial loss of absorbed gases of 0.0013 g/g at elevated temperature. The excellent thermal stabihty of ETEE is demonstrated by aging at 180°C at this temperature, the annual weight loss of six parts per 1000, or a 1% weight loss, takes almost two years. 

Vacuum Outgassing and Permeability. Under vacuum, modified ethylene—tetrafluoroethylene copolymers give off Htde gas at elevated temperatures. The loss rate is about one-tenth of the acceptable maximum rates for spacecraft uses. Exposing 750-pm specimens for 24 h at 149°C to a high vacuum results ia a maximum weight loss of 0.12% volatile condensible material is less than 0.02%. 

The color of red meat depends on oxygen. The color of the meat pigment myoglobin is purple. The bright red color of the fresh-as-cut meat is from oxymyoglobin. To preserve red meat, the objectives are to retard spoilage and weight loss, and to deUver red color at the consumer level. 

The definition of polymer thermal stabiUty is not simple owing to the number of measurement techniques, desired properties, and factors that affect each (time, heating rate, atmosphere, etc). The easiest evaluation of thermal stabiUty is by the temperature at which a certain weight loss occurs as observed by thermogravimetric analysis (tga). Early work assigned a 7% loss as the point of stabiUty more recentiy a 10% value or the extrapolated break in the tga curve has been used. A more reaUstic view is to compare weight loss vs time at constant temperature, and better yet is to evaluate property retention time at temperature one set of criteria has been 177°C for 30,000 h, or 240°C for 1000 h, or 538°C for 1 h, or 816°C for 5 min (1). 

Aliphatic—aromatic poly(amide—imides) based on N,1S7-bis(carboxyalkyl)-benzophenone-3,3, 4,4 -tetracarboxyhc diimides have shown a 10% weight loss at 400°C (14). 

These polymers show thermal stabiUty in the range 300—340°C (10% weight loss) and inherent viscosities of 0.15—0.45 dL/g. 

LARC-TPI is a linear thermoplastic PI which can be processed ia the imide form to produce large-area, void-free adhesive bonds. Mitsui Toatsu Chemicals, Inc., has obtained Hcense to produce this product commercially for appHcations such as adhesives, films, mol ding compounds, etc. These are thermooxidatively stable and show essentially no loss ia weight at 300°C ia air. Weight loss does not exceed 2—3% after isothermal aging ia air at 300°C for 550 h. 

The PODs obtained from aromatic dihydra2ides are partiy soluble in dimethyl-acetamide, DMSO, etc the others dissolve in these solvents. The thermal stabihties (up to 464°C in air and 476°C in nitrogen (10% weight loss)) of the polymers were determined by tga. 

Polyquinolines have also been obtained by a post-polymerization thermal treatment of poly(enamino nitriles) (93). The resulting polymers show excellent thermal stabiUty, with initial weight losses occurring between 500 and 600°C in air (tga) under nitrogen, initial weight loss occurs at about 600°C and there is a 20% weight loss up to 800°C. 

A polyester backbone with two HFIP groups (12F aromatic polyester of 12F-APE) was derived by the polycondensation of the diacid chloride of 6FDCA with bisphenol AF or bisphenol A under phase-transfer conditions (120). These polymers show complete solubkity in THF, chloroform, ben2ene, DMAC, DMF, and NMP, and form clear, colorless, tough films the inherent viscosity in chloroform at 25°C is 0.8 dL/g. A thermal stabkity of 501°C (10% weight loss in N2) was observed. 

Numerous avenues to produce these materials have been explored (128—138). The synthesis of two new fluorinated bicycHc monomers and the use of these monomers to prepare fluorinated epoxies with improved physical properties and a reduced surface energy have been reported (139,140). The monomers have been polymerized with the diglycidyl ether of bisphenol A, and the thermal and mechanical properties of the resin have been characterized. The resulting polymer was stable up to 380°C (10% weight loss by tga). 

Metformin. Metformin [657-24-9] (1,1-dimethylbiguanide), mol wt 129.17, forms crystals from propanol, mp 218—220°C, and is soluble in water and 95% ethanol, but practically insoluble in ether and chloroform. Metformin, an investigational dmg in the United States, does not increase basal or meal-stimulated insulin secretion. It lowers blood glucose levels in hyperglycemic patients with Type II diabetes but has no effect on blood glucose levels in normal subjects. It does not cause hypoglycemia. Successful metformin therapy usually is associated with no or some weight loss. 

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