This study uses a computer model to simulate a quadrupole mass filter (QMF) instrument under different operating conditions for Mathieu stability zones 1 and 3. The investigation considers the factors that limit the maximum resolution (R(max)), which can be obtained for a given QMF for a particular value of scan line. Previously, QMF resolution (R) has been found to be dependent on number (N) o...

The injection of liquid from a central well into a partially saturated aquifer of finite thickness is described using similarity solutions. The solutions illustrate that injection leads to a growing zone around the source in which the fluid fills the whole depth of the aquifer. Beyond this zone, the current adjusts to the depth in the far field as the fluid slumps under gravity. The radial exte...

to design subsurface drainage systems, it is necessary to determine the saturated hydraulic conductivity of the soil. one of the most common methods for field measurement of this parameter is the shallow well pump-in test method. another method which has recently been introduced for the above measurement is the guelph permeameter method. both methods are used to measure the soil saturated hydra...

Protection of water resources from contamination and detection of the contaminants and their treatments are among the essential issues in the management of water resources. In this work, the time-lapse electrical resistivity tomography (ERT) surveys were conducted along 7 longitudinal lines in the downstream of the Latian dam in Jajrood (Iran), in order to detect the contamination resulting fro...

In this paper we formulate a system of partial diierential equations that models the contamination of groundwater due to migration of dissolved contaminants through unsaturated to saturated zone. A closed form solution using singular perturbation techniques for the water ow and solute transport equations in the unsaturated zone is given. Indeed, the solution can be used as a tools to verify the...

While most hydrological models reproduce the general flow dynamics, they frequently fail to adequately mimic system-internal processes. In particular, the relationship between storage and discharge, which often follows annual hysteretic patterns in shallow hard-rock aquifers, is rarely considered in modelling studies. One main reason is that catchment storage is difficult to measure, and anothe...

.n a number of geothermal systems, including the 3eysers (Ca), Lardarello (Italy) and Tongonan :Philippines), well logs indicate that in some parts of he reservoir, a two-phase vapouror liquid-dominated -egion is overlain by a colder liquid saturated zone. The stability of such systems is intriguing. Schubert md Straus (1980) have described how a liquid layer nay overly a model superheated vapo...

Under the conditions normally used for detritylation in oligonucleotide synthesis, the haloacetic acid binds strongly to the oligonucleotide. Acetonitrile also forms a complex with the deblocking acid, in competition with the oligonucleotide, and drastically slows detritylation. Incomplete removal of acetonitrile during the deblock step may slow the kinetics enough to result in incomplete detri...