abstract pedotransfer functions (ptfs) are useful means of prediction many properties of the soil, and especially the hydraulic characteristics of this porous media. the main advantages of this functions, as compare to conventional methods used to directly estimate soil hydraulic properties, is that they are not time-cost consuming. different approaches such as classic linear and non linear reg...

fleas are the most common and important external parasites worldwide and also serves as vectors of various pathogens for humans and animals. the study aimed to determine the prevalence of pulex irritants in sheep herds and residential areas of villages in kurdsitan province, iran. a total of 2,900 sheep were randomly selected from 48 flocks and 630 residential areas of 18 villages from november...

The aim of this research was to investigate the long-term hydraulic conductivity changes in sand-bed columns exposed to 2,4,6-trichlorophenol (TCP). Continuous flow laboratory studies were conducted using sand-bed columns (15 cm i.d.; 200 cm length) at 20+/-1 degrees C during 365 d. The influence of (i) initial loads of 2,4,6-TCP (15, 30, 45 and 60 mg kg(-1) of 2,4,6-TCP), and (ii) recirculatin...

This study investigates the feasibility of using coal fly ash and fly ash-bentonite mixtures as a barrier material for mine waste. The hydraulic conductivity of the coal fly ash was measured to be in the order of 2 x 10 -9 m/s when it was permeated with deionized water, and this value decreased significantly when the permeant was switched to acid mine drainage (AMD). Addition of bentonite to co...

The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and roo...

Management of groundwater contamination is a very cost-intensive proposition filled with conflicting objectives and substantial uncertainty. A critical source of this uncertainty in groundwater problems comes from the data for the conductivity values for the aquifer on which the flow and transport of the contaminant is dependent. For a remediation solution to be reliable in practice it is impor...

The interpretation of falling-head tests in cased boreholes is discussed. These tests are commonly used to measure hydraulic conductivity of compacted clay liners and are often part of the construction quality assurance program. Three methods of interpretation are reviewed with data sets collected from real tests. Two of these methods have been the subject of past research by other authors: the...

Previous studies of the hydraulic conductivity of connective tissues have failed to show a correspondence between ultrastructure and specific hydraulic conductivity. We used the technique of quick-freeze/deep-etch to examine the ultrastructure of the corneal stroma and then utilized morphometric studies to compute the specific hydraulic conductivity of the corneal stroma. Our studies demonstrat...

A prerequisite for reliable hydraulic measurements is an accurate collection of the plant material. Thereby, the native hydraulic state of the sample has to be preserved during harvesting (i.e., cutting the plant or plant parts) and preparation (i.e., excising the target section). This is particularly difficult when harvesting has to be done under transpiring conditions. In this article, we pre...

Many groundwater remediation designs for contaminant plume containment are developed using mathematically based groundwater now models. These mathematical models are most eiTective as predictive tools when the parameters that govern groundwater flow are known with a high degree of certainty. The hydraulic conductivity of an aquifer, however, is uncertain, and so remediation designs developed lI...