Evaluation of Variation in Permeability Measurements when Using the MARK VI Standpipe

1989 ◽  
Vol 46 (3) ◽  
pp. 447-450 ◽  
Author(s):  
Michael K. Young ◽  
Wayne A. Hubert ◽  
Thomas A. Wesche
Keyword(s):  
Sampling Strategy ◽  
Repeated Readings ◽  
Constant Flow ◽  
Flow Conditions ◽  
Coefficients Of Variation ◽  
Repeated Sampling ◽  
Change In The Mean ◽  
The Mean ◽  
A Site

Using the MARK VI standpipe in a substrate-filled flume under constant flow conditions, we found significant differences in permeability readings made by different people at four of five sites. Coefficients of variation at each site ranged from 27 to 79%. Readings usually varied greatly for each person at each site. To detect a 10% change in the mean permeability at single sites (α = 0.05) would require from 34 to 90 samples; for a 30% change, the range was 4 – 10. Repeated sampling at a site did not produce directional changes in permeability estimates, nor did the performance of individuals change during the test. We propose a sampling strategy based on repeated readings taken by one person.

COMPARISONS OF METHODS OF pH DETERMINATION FOR ORGANIC TERRAIN SURVEYS

1973 ◽  
Vol 53 (2) ◽  
pp. 177-183 ◽  
Author(s):  
W. STANEK
Keyword(s):  
Ph Value ◽  
Liquid Limit ◽  
Natural State ◽  
Confidence Limits ◽  
Practical Application ◽  
Oven Drying ◽  
Ph Values ◽  
Coefficients Of Variation ◽  
The Mean ◽  
A Site

pH values were measured on peat samples taken from a water-logged peatland in Ontario, from April 1970 to April 1971, by 14 procedures: on fresh peat and groundwater, in their natural state; and on combinations of hand-squeezed, air-dried, and oven-dried peat, each rewetted to liquid limit with either distilled H2O, N/100 CaCl2∙2H2O, N/10 KCl, or N/10 CaCl2∙2H2O. Groundwater showed the highest mean pH (4.0), followed by hand-squeezed peat rewetted with distilled H2O (3.8), then fresh peat (3.6). In comparison with fresh peat, air and oven drying lowered the mean pH value by 0.1 and 0.2 units, rewetting with N/100 CaCl2∙2H2O, by 0.4; N/10 KCl, by 0.5; and N/10 CaCl2∙2H2O, by 0.6 units approximately. The coefficients of variation and the confidence limits showed, for practical application, that all methods were equally reliable and that pH determined at any time of the year validly characterized a site.

Estimation of Submergent Plant Bed Biovolume using Acoustic Range Information

1990 ◽  
Vol 47 (4) ◽  
pp. 805-812 ◽  
Author(s):  
G. L. Thomas ◽  
S. L. Thiesfeld ◽  
S. A. Bonar ◽  
R. N. Crittenden ◽  
G. B. Pauley
Keyword(s):  
Plant Biomass ◽  
Direct Estimate ◽  
Cross Sectional ◽  
Devils Lake ◽  
Coefficients Of Variation ◽  
Change In The Mean ◽  
Acoustic Surveys ◽  
The Mean ◽  
Fish Interactions ◽  
Chart Recording

Acoustic measurements of the distance between the water surface, top of the aquatic plants, and bottom of the water column were made using chart recording echosounders. The vertical cross sectional area (m2), height (m), biovolume (m3), of aquatic plant beds and variances were computed for three surveys of Devils Lake, Oregon, in May, July, and September, 1986 when coefficients of variation for the plant bed biovolume estimates were 0.18, 0.05, and 0.06, respectively (n = 14). Coefficients of variation for plant biomass estimates (g/m2) computed from SCUBA quadrat samples collected concurrently with the acoustic surveys, were 0.98 (n = 48), 0.81 (n = 90), and 1.05 (n = 90), respectively. The higher precision of the biovolume estimates allow for a 5- to 18-fold greater capability to detect a change in the mean. The lower costs of the biovolume estimates allow for a 10- to 33-fold greater precision-for-cost. The plant bed biovolume variable contains ecologically different information than the biomass variable in that it provides a direct estimate of the amount of aquatic habitat in a lake that is influenced by plants; it should prove useful for evaluating plant control practices and possibly for studying plant-fish interactions.

Genetic, maternal, and tank determinants of growth in hatchery-reared juvenile Arctic charr (Salvelinus alpinus)

1991 ◽  
Vol 69 (3) ◽  
pp. 655-660 ◽  
Author(s):  
B. G. E. de March
Keyword(s):  
Egg Size ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Logistic Growth ◽  
Coefficients Of Variation ◽  
The Social ◽  
Change In The Mean ◽  
Factorial Mating ◽  
Unique Distribution ◽  
The Mean

The relative importance of genetic, maternal, and tank effects on the growth of juvenile Arctic charr (Salvelinus alpinus) was examined in an incomplete factorial mating design (4 dams × 4 sires) with stock from the Fraser River, Labrador, Canada. Egg size and hatching success were related only to dams. Mean weights at 30, 75, and 125 days after swim-up, logistic growth curve parameters describing the change in the mean weight, and a measure of condition, all described within families, were significantly related to both dams and sires and were also correlated with each other. The early patterns of significant differences due to dams and sires changed after approximately 125 days. After this time the mean weights in tanks, although still increasing, became negatively correlated with their coefficients of variation (CV), which had changed only slightly with time. The magnitude of the CVs could not be attributed to specific parents. The changed patterns of differences in the means with time suggested that either (i) the social climate within tanks, measured as the CV, affected the growth of all fish even though they were neither crowded nor underfed, or (ii) an individual's ability to grow was dependent not only on its phenotype (initial weight) but also on its genotype, expressed only in data from sibs. These laboratory results may relate to unique distribution and fitness characteristics of natural Arctic charr populations.

scholarly journals Forensic Investigation of Four Monitored Green Infrastructure Inlets

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1787
Author(s):  
Leena J. Shevade ◽  
Franco A. Montalto
Keyword(s):  
Measurement Uncertainty ◽  
Green Infrastructure ◽  
Stormwater Management ◽  
Catchment Area ◽  
Low Flow ◽  
Inflow Rate ◽  
Forensic Investigation ◽  
Flow Conditions ◽  
The Mean

Green infrastructure (GI) is viewed as a sustainable approach to stormwater management that is being rapidly implemented, outpacing the ability of researchers to compare the effectiveness of alternate design configurations. This paper investigated inflow data collected at four GI inlets. The performance of these four GI inlets, all of which were engineered with the same inlet lengths and shapes, was evaluated through field monitoring. A forensic interpretation of the observed inlet performance was conducted using conclusions regarding the role of inlet clogging and inflow rate as described in the previously published work. The mean inlet efficiency (meanPE), which represents the percentage of tributary area runoff that enters the inlet was 65% for the Nashville inlet, while at Happyland the NW inlet averaged 30%, the SW inlet 25%, and the SE inlet 10%, considering all recorded events during the monitoring periods. The analysis suggests that inlet clogging was the main reason for lower inlet efficiency at the SW and NW inlets, while for the SE inlet, performance was compromised by a reverse cross slope of the street. Spatial variability of rainfall, measurement uncertainty, uncertain tributary catchment area, and inlet depression characteristics are also correlated with inlet PE. The research suggests that placement of monitoring sensors should consider low flow conditions and a strategy to measure them. Additional research on the role of various maintenance protocols in inlet hydraulics is recommended.

scholarly journals Quantifying the Effects of Wave—Current Interactions on Tidal Energy Resource at Sites in the English Channel Using Coupled Numerical Simulations

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3625
Author(s):  
Jon Hardwick ◽  
Ed B. L. Mackay ◽  
Ian G. C. Ashton ◽  
Helen C. M. Smith ◽  
Philipp R. Thies
Keyword(s):  
Wave Model ◽  
Tidal Energy ◽  
English Channel ◽  
Flow Conditions ◽  
Mean Flow ◽  
Radiation Stress ◽  
Large Wave ◽  
Stress Gradients ◽  
The Mean ◽  
Flow Power

Numerical modeling of currents and waves is used throughout the marine energy industry for resource assessment. This study compared the output of numerical flow simulations run both as a standalone model and as a two-way coupled wave–current simulation. A regional coupled flow-wave model was established covering the English Channel using the Delft D-Flow 2D model coupled with a SWAN spectral wave model. Outputs were analyzed at three tidal energy sites: Alderney Race, Big Roussel (Guernsey), and PTEC (Isle of Wight). The difference in the power in the tidal flow between coupled and standalone model runs was strongly correlated to the relative direction of the waves and currents. The net difference between the coupled and standalone runs was less than 2.5%. However, when wave and current directions were aligned, the mean flow power was increased by up to 7%, whereas, when the directions were opposed, the mean flow power was reduced by as much as 9.6%. The D-Flow Flexible Mesh model incorporates the effects of waves into the flow calculations in three areas: Stokes drift, forcing by radiation stress gradients, and enhancement of the bed shear stress. Each of these mechanisms is discussed. Forcing from radiation stress gradients is shown to be the dominant mechanism affecting the flow conditions at the sites considered, primarily caused by dissipation of wave energy due to white-capping. Wave action is an important consideration at tidal energy sites. Although the net impact on the flow power was found to be small for the present sites, the effect is site specific and may be significant at sites with large wave exposure or strong asymmetry in the flow conditions and should thus be considered for detailed resource and engineering assessments.

An Assessment of Sampling Methods and Microbiological Hygiene Indicators for Process Verification in Poultry Slaughterhouses

2006 ◽  
Vol 69 (1) ◽  
pp. 145-153 ◽  
Author(s):  
M. L. HUTCHISON ◽  
L. D. WALTERS ◽  
G. C. MEAD ◽  
M. HOWELL ◽  
V. M. ALLEN
Keyword(s):  
Storage Time ◽  
Sampling Method ◽  
Indicator Bacteria ◽  
Aerobic Bacteria ◽  
Process Verification ◽  
Bacterial Indicator ◽  
Coefficients Of Variation ◽  
Microbiological Testing ◽  
The Mean ◽  
Poor Relationship

Studies to determine the appropriateness of the use of populations of indicator bacteria on poultry carcasses for process verification were undertaken in commercial slaughterhouses. Samples were collected from neck skin by excision or from whole carcass rinses and were examined for a range of presumptive process hygiene indicator bacteria. Coefficients of variation were calculated for each bacterial indicator and were significantly lower in excised samples, indicating more reproducible bacterial recovery by this sampling method. Total viable counts of aerobic bacteria, Enterobacteriaceae, and Pseudomonas in samples collected by excision had the lowest coefficients of variation when compared with other indicators and were therefore used for further study. The uncertainties associated with the quantification of each bacterial indicator were calculated and were lowest overall for total viable counts of aerobic bacteria. In general, uncertainty was higher for lower bacterial numbers. Results of microbiological testing on pooled excised neck skin samples were not significantly different from the mean of individually analyzed samples. Bacterial numbers increased by 1 log unit when cultures were stored under chilled conditions typical of those used for transporting samples to external laboratories, but the increases were not significant for Pseudomonas and aerobic bacteria when storage time was less than 17 h. Weak relationships were identified between bacterial indicator numbers and duration of processing, although cleanliness of the processing environment diminished visibly during this time. In the plants visited for this study, there was a poor relationship between presumptive bacterial indicator numbers and process hygiene. Consequently, bacterial analyses for process verification purposes may be of limited value.

Haemorheological Effects on Thrombocyte Adhesion and Aggregation Found Under Controlled Flow Conditions

1979 ◽  
Author(s):  
P.D. Richardson
Keyword(s):  
Rate Of Change ◽  
Continuous Observation ◽  
Flow Conditions ◽  
Wide Range ◽  
Stream Migration ◽  
Local Shear ◽  
Videotape Recording ◽  
Controlled Flow ◽  
A Site

Thrombocyte adhesion and aggregation in a vessel or on a chamber wall can be measured most readily if the flow is controlled and steady, and continuous observation is used. Videotape recording is very helpful for subsequent quantification of the dynamics. The adhesion of each thrombocyte can occur for a finite time interval:this interval has been observed to have a wide range. Platelets which escape often leave open a site which attracts other platelets preferentially. The rate of change of adhesion density (platelets/mm2) is affected by the local shear rate and the shear history upstream. Aggregation is affected similarly, and also proceeds with some platelet turnover. The role of erythrocytes in facilitating cross-stream migration of thrombocytes (which can enhance the growth rate of large thrombi) appears due in part to convective flow fields induced by the motion of erythrocytes in a shear flow, which can be demonstrated theoretically and experimentally. Observations of the phenomenlogy of adhesion and aggregation under controlled flow conditions and comparison with fLu id-dynamically based theory allows representation in terras of a small number of parameters with prospects of prediction of behaviour over a wide range of haemodynamic conditions; biochemical changes lead to changes in values of the parameters, so that activating agents and inhibiting agents modify values in different directions.

LRF and TRF test during long-term danazol treatment: increase of the LH and FSH responses but decrease of the prolactin and TSH responses

1983 ◽  
Vol 104 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. Leppäluoto ◽  
L. Rönnberg ◽  
P. Ylöstalo
Keyword(s):  
Clinical Symptoms ◽  
Follicular Phase ◽  
Blood Samples ◽  
Hormone Levels ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Thyroid Hormone Levels ◽  
Low Serum

Abstract. Seven patients suffering from severe endometriosis were treated with danazol 200 mg × 3 daily for 6 months. Clinical symptoms were alleviated and menses disappeared in response to the treatment. After cessation of the treatment the menstrual bleedings returned in 1–3 months. Blood samples for determination of gonadotrophins, prolactin (Prl), oestradiol (E2), progesterone, thyroid hormones and thyrotrophin in radioimmunoassays were taken and a combined TRF and LRF test carried out in the follicular phase before treatment, at the 6th month of treatment and after reappearance of the first menses. There were no statistically significant changes in the basal levels of serum FSH, LH or TSH during the danazol treatment. Neither was there any change in episodic secretions of FSH, LH or Prl, as determined by the mean coefficients of variation of the hormone levels in seven consecutive samples taken at 20 min intervals. On the other hand, serum E2, Prl and thyroid hormone levels were significantly decreased in the 6th month of treatment. In the TRF-LRF test the responses of serum FSH and LH were significantly higher and those of serum Prl and TSH significantly lower during danazol treatment than before. Prl responses remained lowered after the treatment. It appears that low serum oestrogen levels, induced by the danazol treatment, sensitize the pituitary gonadotrophs to exogenous LRF, but make the sensitivity of thyrotrophs and lactotrophs lower to exogenous TRF. These results thus indicate that danazol does not make the pituitary gonadotrophs insensitive to LRF, but danazol may rather inhibit the secretion of hypothalamic LRF.

The Estimation of Discharge in an Experimental Open Channel

2014 ◽  
Vol 905 ◽  
pp. 369-373
Author(s):  
Choo Tai Ho ◽  
Yoon Hyeon Cheol ◽  
Yun Gwan Seon ◽  
Noh Hyun Suk ◽  
Bae Chang Yeon
Keyword(s):  
Unsteady Flow ◽  
River Discharge ◽  
Open Channel ◽  
Flow Conditions ◽  
Mean Velocity ◽  
Velocity Equation ◽  
The Mean ◽  
Loop Form

The estimation of a river discharge by using a mean velocity equation is very convenient and rational. Nevertheless, a research on an equation calculating a mean velocity in a river was not entirely satisfactory after the development of Chezy and Mannings formulas which are uniform equations. In this paper, accordingly, the mean velocity in unsteady flow conditions which are shown loop form properties was estimated by using a new mean velocity formula derived from Chius 2-D velocity formula. The results showed that the proposed method was more accurate in estimating discharge, when compared with the conventional formulas.

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