Room-temperature Distilled Water Research Articles

Method for detecting hemodynamic alterations following a single gavage in rats.

It is known that administering a gavage to rodents evokes a cardiac reflex, due to gastrointestinal stimulation. Consequently, it is difficult to evaluate changes in hemodynamics after a single oral dose of a pungent or astringent, which alters the circulation by increasing sympathetic activity. In the present study, we developed a method for administering a gavage without significantly affecting hemodynamics measurements. We marked a gastric tube at 10 cm from the tip, to mark the distance from the oral cavity to the stomach body of Wistar male rats. Rats were intubated under urethane anesthesia.After 10–15 min of stabilization, we measured the mean blood pressure (MBP), heart rate (HR), and blood flow (BF) in the cremaster arteriole under two different conditions; condition 1: a pointed gastric tube, room temperature distilled water, and injected at normal speed (approximately 3 ml/min); condition 2: a rounded gastric tube, 37°C distilled water, and injection at 1.0 ml/min. Under condition 1, we observed striking hemodynamic alterations, due to the somatic afferent reflex. In contrast, under condition 2, these hemodynamic changes were nearly eliminated. In addition, we could clearly detect hemodynamic changes in rats after a single gavage treatment of pungent (capsaicin) or astringent (cinnamtannin A2). We observed transient increases in the HR and MBP soon after treatment with capsaicin. Moreover, cremasteric BF was elevated with cinnamtannin A2. These results confirmed the utility of the gavage method developed in this study.

Mass Flux Distribution Measurements and Visualizations of a Fluid Sheet Generated by a Partially Immersed Dip-Lubricated Gear

A simplified model of gearbox lubrication flow is investigated. A metric gear with module size 4 mm, tooth number 38, tip radius 80.25 mm and width 40 mm, is partially immersed and rotated between 0–12 1/s frequencies in room temperature distilled water. Flash and laser sheet visualizations of the global flow field and the boundary layer are presented. Resolved mass flow distributions in the fluid sheet above the water surface are obtained with in-situ liquid trapping (bucketing). The relation between the circumferential velocity and integrated mass flux of the fluid sheet is found to be linear above a critical speed, for which an analytical formula is given. Using dimensional analysis, we show that the relation between the mass flux and gear speed signifies a Reynolds-number independent behavior of the boundary layer around the immersed part of the gear.

Effect of water chemistry on calcium carbonate deposition on metal and polymer surfaces

The formation of calcium carbonate on the surfaces of polypropylene and copper tubes was studied by exposing tubes to a laminar flow of room temperature distilled water, supersaturated with respect to calcite. Three water chemistries were used: a control (pH 9.3), one with lower supersaturation but similar pH as the control, and one with higher pH (pH 11) but similar supersaturation as the control. The accumulation of calcium carbonate with time was characterized along with the microstructure and the crystal structure of the deposits. On both tube materials, the amount of calcium carbonate deposited per unit surface area increased with time. At any given time, the accumulation was significantly less when the low supersaturation water was used. For all three water chemistries, more calcium carbonate formed on polyproplyene as compared with copper, with the greatest difference between the two noted for the higher pH water. The deposits consisted of discrete particles and particle clusters, the number and size of which increased with time. Calcite was the dominant polymorph for deposits on copper. On polyproplyene, the deposits were a mixture of calcite, vaterite and aragonite with aragonite dominating except at low supersaturation. A simple model for the mass accumulation of particulate-based deposits with time is presented and the factors responsible for the differences between materials are discussed.

The mechanical behavior of ceramic–metal laminate under thermal shock

A new material system for applications involving thermal shock is proposed. The system consists of thin layers of ceramics and thinner metallic interlayers. In this study, a ceramic/metal laminate was constructed from Coor's ADS96R thin plates alternating with thinner Wesgo Cusil Active Braze Alloy interlayer foils and joined in active brazing. The maximum brazing temperature was 845 °C. Square laminated plates were quenched in room-temperature distilled water, where a very large heat transfer coefficient exists, and therefore, severe conditions of thermal shock occur. The laminated plates, initially at temperatures of 600 and 800 °C, were quenched at their bottom surface only in a specially designed apparatus. The temperatures at the top and the bottom surfaces of the specimens were measured by means of two thermocouples during quenching. The basic features of this architecture are described. The dominant behavior was the absence of interaction between the biaxial cracking mechanisms in a ceramic layer with those in an adjacent ceramic layer, and localization of the damage to those layers that experienced sufficient tensile stresses. The result was a dramatic increase of the residual strength after thermal shock. In addition, R-curve behavior upon mechanical loading caused by plastic deformation of the metallic interlayer was observed.

Fatigue Strength as a Function of Preloading in Dynamic Fatigue Testing of Glass and Ceramics

The solution of fatigue strength as a function of preloading in dynamic fatigue (constant stress-rate) testing was obtained analytically and numerically. The effect of preloading on dynamic fatigue strength decreases with increasing fatigue parameter (n), and for n ≥ 20 the effect is negligible up to a preloading of 90 percent. The solution was verified by dynamic fatigue experiments conducted with soda-lime glass and alumina specimens in room-temperature distilled water. This result showed that one can apply a preloading corresponding up to 90 percent of fatigue strength for most glass and ceramic materials, resulting in a dramatic saving of testing time in dynamic fatigue testing. The key feature that makes this technique feasible is that most of the slow crack growth under dynamic fatigue loading occurs close to failure time where the dynamic fatigue strength is defined.

Cyclic fatigue of brittle materials with an indentation-induced flaw system

The ratio of static to cyclic fatigue life, or ‘ h ratio’, was obtained numerically for an indentation flaw system subjected to sinusoidal loading conditions. Emphasis was placed on developing a simple, quick lifetime prediction tool. The solution for the h ratio was compared with experimental static and cyclic fatigue data obtained from as-indented 96 wt.% alumina specimens tested in room-temperature distilled water.

Ovine fetal swallowing and behavioral state responses to sublingual water.

Ovine fetal swallowing primarily occurs in bouts of activity associated with low voltage electrocorticogram activity and breathing movements. Despite similar rates of electromyographic swallowing activity, there are significant differences in the net esophageal fluid flow among fetuses. To determine if variations in the volume of fluids accessible to the fetus (amniotic fluid, lung fluid, salivary secretions) affect fetal swallowing, we studied the effects of sublingual distilled water infusions on ovine fetal swallowing rates and esophageal flow. Seven pregnant ewes at 127 +/- 2 days gestation were chronically instrumented with maternal and fetal vascular catheters, fetal electrocortical, electro-ocular and electromyograph electrodes, an esophageal flow probe and a sublingual infusion catheter. Following a 2-hour control period, consecutive sublingual infusions of room temperature distilled water (10 and 20 ml/kg/h) were administered for 2 h each. In response to sublingual infusions, fetal plasma sodium (142.5 +/- 0.5 to 140.8 +/- 0.8 mEq/l), chloride concentrations (109.2 +/- 0.4 to 107.7 +/- 0.7 mEq/l) and osmolality (302 +/- 2 to 298 +/- 2 mOsm/kg) decreased significantly. Swallowing activity and esophageal flow did not change significantly from basal values (47 +/- 9 swallows/h, 19.2 +/- 4.2 ml/h) during the sublingual infusions. However, fetal low-voltage electrocortical activity increased significantly during both infusion periods (42 +/- 3 to 56 +/- 6%). Sublingual distilled water infusion decreases fetal plasma osmolality and alters fetal behavioral state without affecting swallowing frequency or esophageal flow.

Statistical study of the effect of subcritical crack growth on thermal shock resistance

An experimental study of the effects of subcritical crack growth on thermal shock damage is presented, based on a statistical analysis of the retained strength distribution. Single-quench thermal shock and thermal shock fatigue tests were performed in a room-temperature distilled water bath on glass microscope slides. Experimental results indicate that subcritical crack growth effects are observable in the shock testing of glass slides in terms of systematic shifts in the retained strength distribution.

EFFECT OF MODE OF REHYDRATION ON TEXTURAL PARAMETERS OF PRECOOKED FREEZE-DRIED SLICED BEEF.

Rehydration procedure had a significant effect on microscopic appearance, manner of liquid release on mechanical chewing, numerical values for the mechanical parameters of texture, correlations between objective measurements (Warner-Bratzler Tenderometer, Kramer Shear Press and General Foods Texturometer) and the ability of instrumental measurements to show grade and cooking level effects. To a lesser extent, it also affected residual errors and coefficients of variation. As compared to cold distilled water, rehydration in warm 1% NaCl appeared to toughen the meat fibers while allowing more water to be absorbed intrafibrally. This water did not release easily on mechanical chewing. Overnight equilibration of drained samples increased the diameter of meat fibers, roughness of those rehydrated in the hot salt solution and smoothness of those rehydrated in cold distilled water. Best approximation to the microscopic appearance of fresh cooked beef was obtained by 20 min rehydration in room temperature distilled water followed by overnight equilibration in the refrigerator. This procedure also offered good differentiation of meat grade and cooking time effects by instrumental texture measurements.