The objectives of this review are to summarize existing information on the occurrence of pesticides In groundwater and processes resulting in their detection; to identify existing technologies, and to describe missing information needed to make assessments arid predictions. Validated data on the occurrence of pesticides in groundwater are still limited. Pesticides can reach groundwater followin...

Water and osmotic potential energies were measured with thermocouple psychrometers, at intervals during a 4-week period, in growing leaves of bean (Phaseolus vulgaris, var. Blue Lake) and barley (Hordeum vulgare, var. Liberty) plants having roots equally split between 2 differentially salinized nutrient solutions. The osmotic potentials of plants with half their roots in saline solutions were a...

With an elevator installed in a 90-meter tall Sequoiadendron to collect the samples, xylem pressure potential measurements were made approximately every 15 meters along 60 meters of the tree's height. The measured gradient was about -0.8 bar per 10 meters of height, i.e., less than the hydrostatic gradient. Correction of the xylem pressure potential data by calibration against a thermocouple ps...

Nanotechnology is an emerging technology that could impact a wide range of industries in the near future. Nanotechnology involves production and use of extremely small particles (1 – 100 nm size scale), wherein the particle synthesis is controlled or manipulated at the molecular level (1). The nanoparticles are often used for industrial/commercial applications due to their extremely high reacti...

A polarizable water pair potential was determined by fitting a potential form to microwave, terahertz, and mid-infrared (D2O)2 spectra through a rigorous calculation of the water dimer eigenstates. It accurately reproduces most ground state vibration-rotation-tunneling spectra and yields excellent second viral coefficients. The calculated dimer structure and dipole moment are very close to thos...

Water potential (Psiomega) values were determined for aqueous colloids of four molecular sizes of polyethylene glycol (PEG) using freezing-point depression and vapor-pressure deficit methods. A significant third-order interaction exists between the method used to determine Psiomega, PEG molecular size, and concentration. At low PEG concentrations, freezing-point depression measurements result i...

A new interatomic potential for dissociative water was developed for use in molecular dynamics simulations. The simulations use a multibody potential, with both pair and three-body terms, and the Wolf summation method for the long-range Coulomb interactions. A major feature in the potential is the change in the short-range O-H repulsive interaction as a function of temperature and/or pressure i...