Stringently anaerobic bacteria have been successfully cultured in rubber-stoppered roll tubes. Stoppers of certain types of rubber are so permeable to oxygen that they are unsuitable (Hungate, J. Bacteriol. 86:848, 1963). Butyl rubber is less permeable to gases than are many other types. The permeabilities of butyl stoppers and a common laboratory type to gases concerned in anaerobic culture wo...

Remedial dredging of contaminated bed sediments in rivers and lakes results in the suspension of sediment solids in the water column, which can potentially be a source for evaporation of hydrophobic organic compounds (HOCs) associated with the sediment solids. Laboratory experiments were conducted in an oscillating grid chamber to simulate the suspension of contaminated sediments and flux to ai...

A flowmeter is described which may be used to measure gas flow in experimental situations. It may be adapted for use with any gas or gas mixture and be used to provide flows as small as 50 ml min-1. A mercury-in-glass manometer (sphygmomanometer) is used to measure the gas pressure proximal to a flow restrictor (consisting of a hypodermic needle hub) and it is this pressure head which, for a gi...

background: tension and stress are among the factors that lead to hypertension. in most individuals, behavioral strategies, such as relaxation and massage, are effective in controlling the individuals’ response to stress, thus reducing hypertension. methods: this non-blind clinical trial was conducted on 90 patients with primary hypertension. the patients were randomly divided into a control an...

The pressure variations associated with a filling undulating pipeline containing an entrapped air pocket are investigated both experimentally and numerically. The influence of entrapped air on abnormal transient pressures is often ambiguous because the compressibility of the air pocket permits the liquid flow to accelerate but also partly cushions the system, with the balance of these tendencie...

We report exploratory experiments simulating gas-driven eruptions using the C02H20 system at room temperature as an analog of natural eruptive systems. The experimental apparatus consists of a test cell and a large tank. Initially, up to 1.0 wt % of C02 is dissolved in liquid water under a pressure of up to 735 kPa in the test cell. The experiment is initiated by suddenly reducing the pressure ...

The sandy sediments that blanket the inner shelf are situated in a zone where nutrient input from land and strong mixing produce maximum primary production and tight coupling between water column and sedimentary processes. The high permeability of the shelf sands renders them susceptible to pressure gradients generated by hydrodynamic and biological forces that modulate spatial and temporal pat...

Although small, rural water supplies may present elevated microbial risks to consumers in some settings, characterizing exposures through representative point-of-consumption sampling is logistically challenging. In order to evaluate the usefulness of consumer self-reported data in predicting measured water quality and risk factors for contamination, we compared matched consumer interview data w...