Experimental and numerical study of non-stationary solid-liquid phase transitions of n-tetradecane

During the experiments, four spherical flasks with n-tetradecane with a total mass of 0.344 kg were placed in a test container inside which an aqueous solution of propylene glycol with a mass concentration of 50% and an initial temperature of 25 °C was circulating. As a result of studies, the values of heat flows at different time intervals during the solid-liquid phase transition of n-tetradecane were obtained. Based on the modeling of the processes, the distribution of temperature and velocity of the heat carrier in the test container as well as the values of the local heat transfer coefficients on the surface of the flasks were established. Numerical calculations of the process of phase transition being studied according to the authors’ model were also performed. Numerical calculations of the process under study have been performed using the authors’ model. A satisfactory convergence of the experimental and calculated values of the heat flow has been obtained. The results can be used in the development of thermal energy accumulators with n-tetradecane.

Volume of polyethylene bags for development of papaya seedlings in protected environments

The objective of this study was to test container of polyethylene bags and protected environments on the papaya seedlings production, from May to August of 2008, in Aquidauana state of Mato Grosso do Sul (MS), Brazil. Five bags of polyethylene were used: 7.5 cm x 11.5 cm, 205.9 cm³; 8.4 cm x 10.6 cm, 238.1cm³; 10.0 cm x 16.5 cm, 525.2 cm³; 12.0 cm x 12.0 cm, 550.0 cm³ and 15.0 cm x 21.5 cm, 1539.8 cm³. These containers were placed in three protected environments: greenhouse; screened nursery with Sombrite® and screened nursery with Aluminet®. Because there is no replication of growing environment, each one was considered an experiment. For each cultivation environment, it was adopted a completely randomized design with eight replications of two plants each. Initially, data were submitted to analysis of individual variance of the container (for each cultivation environment), then performing the evaluation of the residual mean squares and the combined analysis of these environments for comparison of protected environments. The greenhouse and nursery with thermal reflector screen produced the best seedlings. The bags of 15.0 x 21.5 cm produced the best papaya seedlings. The Dickson Quality Index pointed the nursery with screen of thermal reflector as the environment that produced the most vigorous seedlings, when using the best container.

CHILD-RESISTANT CONTAINERS CAN PREVENT POISONING

During the period May 1, 1967, to April 30, 1968, prescription tablet and capsule medications from the pharmacies of Madigan General Hospital and McChord Air Force Base were dispensed in 270,000 child-resistant containers. Poisonings from all prescription medications decreased from 15.8 to 8.2 poisonings per 10,000 pediatric outpatient visits. The most significant change was a 90% decrease in poisonings due to prescription tablets and capsules dispensed in plastic vials originating from Madigan and McChord Air Force Base pharmacies during the test period. The study suggests that widespread use of the test container would produce a significant reduction in accidental childhood poisonings due to prescription tablets and capsules.

Results of Testing a Child-resistant Medicine Container

Accidental poisoning, particularly by medications, is a cause of significant morbidity and mortality in children. A practical, inexpensive, child-resistant, medicine container was recently devised and has been tested. The test container is markedly superior to the prescription container presently used by our pharmacy. This test container, widely used, could conceivably lower the incidence of childhood poisonings due to the accidental ingestion of prescription medicines.

Factors Affecting Residue-Film Bioassay of Insecticide Residues

Many factors could affect the mortality of insects and bioassay results: preparation of extracts; method of preparing deposits; loss of volatile insecticides; effect of extractives and additives; age, stage, sex, weight, and species of insects; method of handling insects; size and position of test jars; food used during the test; effect of temperature, humidity, and light; exposure time; contamination of samples; interpretat i on of results; and method of calculating sensitivity. Almost all of these factors affect the mortality of insects, but only a few of them significantly interfere with the final bioassay results if a comparable series of standards is carried on side by side. To obtain more accurate results, all test jars, including the standards, should contain equal amounts of the same extractives; a corresponding standard curve should be prepared from an uncontaminated check for each series of tests; and insects used for each series of tests should be properly sampled from a mixture of several cultures. Within certain limits, the sensitivity of a bioassay may be easily increased by the manipulation of some factors, such as the volume of extract per test jar, age of test insects, size of test container, exposure time, and temperature.