DESIGN OF SEA OUTFALLS - THE LOWER LIMIT CONCEPT OF INITIAL DILUTION.

1983 ◽  
Vol 75 (4) ◽  
pp. 771-774
Author(s):  
NJ BENNETT ◽  
HR OAKLEY ◽  
HA CHARLTON
Keyword(s):  
Lower Limit ◽  
Limit Concept ◽  
Initial Dilution ◽  
Sea Outfalls

Diffuser design for marine outfalls in areas with strong currents, high waves and sediment transport

1995 ◽  
Vol 32 (2) ◽  
pp. 249-255
Author(s):  
Torben Larsen
Keyword(s):  
Sediment Transport ◽  
Far Field ◽  
Initial Dilution ◽  
Environmental Criteria ◽  
The World ◽  
Sea Outfalls ◽  
Environmental Demands

The design of marine outfalls is often based on environmental criteria for a minimum initial dilution. Accordingly advanced diffuser arrangement are designed to fulfil these requirements. A large number of examples of malfunction and blocking in sea outfalls have occurred around the world as a result of this uncompromising consent to environmental demands. Two examples of unconventional design are given in this paper. Both cases involved risk of blockage of the diffuser section because of wave and current induced sediment transport. The paper also discusses how acceptable far field dilution conditions can be achieved even if normally accepted initial criteria are not fulfilled.

scholarly journals THE INFLUENCE OF WAVES ON THE HYDRAULICS OF SEA OUTFALLS

1986 ◽  
Vol 1 (20) ◽  
pp. 190
Author(s):  
Torben Larsen
Keyword(s):  
Sediment Transport ◽  
Initial Dilution ◽  
Typical Data ◽  
Concrete Blocks ◽  
Sea Outfalls

Most of the larger cities in Denmark are located near the sea. About 60% of the sewage is therefore discharged through sea outfalls. Most of these sea outfalls were built in the seventies. In most cases a plastic pipeline were used, and the pipeline was ballasted with armoured concrete blocks and burried in a trench 1 - 2 m underneath the seabottom. To give the necessary initial dilution a diffusor with one or several contracted, horizontal outlets ends the pipeline. The Danish coasts are in general shallow and exposed to waves. The littoral sanddrift is considerably and the sea outfalls need to cross one or more bars. The diffusors are often placed outside the bars, but nevertheless sediment transport can occur around the diffusor. Figure 1 gives some typical data for Danish sea outfalls.

Current U.K. Research into the Design and Operation of Long Sea Outfalls

1989 ◽  
Vol 21 (1) ◽  
pp. 47-54 ◽  
Author(s):  
D. Procter
Keyword(s):  
Marine Environment ◽  
Structural Design ◽  
Performance Monitoring ◽  
Research Programme ◽  
Hydraulic Performance ◽  
Initial Dilution ◽  
Hydraulic Design ◽  
Maintenance And Inspection ◽  
The Uk ◽  
Sea Outfalls

The paper describes the scale of the UK Water Industry's use of the marine environment for the treatment of sewage, and briefly outlines the comprehensive research programme it has instigated to ensure that its outfalls are designed and operated in such a way as to adequately protect the environment. Brief details are provided of the engineering content of the overall UK research programme including work on hydraulic design, initial dilution, structural design and operation, maintenance and inspection. Development of hydraulic performance monitoring procedures and equipment are dealt with in detail and typical results from early fieldvork described.

Supernovae and interstellar gas dynamics

1967 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
F. D. Kahn ◽  
L. Woltjer
Keyword(s):  
Lower Limit ◽  
High Velocity ◽  
Gas Dynamics ◽  
Interstellar Cloud ◽  
Interstellar Gas ◽  
Random Motions ◽  
Relativistic Particles

The efficiency of the transfer of energy from supernovae into interstellar cloud motions is investigated. A lower limit of about 0·002 is obtained, but values near 0·01 are more likely. Taking all uncertainties in the theory and observations into account, the energy per supernova, in the form of relativistic particles or high-velocity matter, needed to maintain the random motions in the interstellar gas is estimated as 1051·4±1ergs.

Factor XII Determinations in the Presence and Absence of Phospholipid Antibodies

1998 ◽  
Vol 79 (01) ◽  
pp. 87-90 ◽  
Author(s):  
D. W. Jones ◽  
M. Winter ◽  
M. J. Gallimore
Keyword(s):  
Lower Limit ◽  
Lupus Anticoagulant ◽  
Factor Xii ◽  
Chromogenic Substrate ◽  
Plasma Samples ◽  
Presence And Absence ◽  
Lower Limit Of Normal

SummaryFactor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal.These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.

Effects of Age and Health on the Euthyroid Reference Ranges for Serum Free Thyroxine and Free Triiodothyronine

1985 ◽  
Vol 24 (02) ◽  
pp. 57-65 ◽  
Author(s):  
J. E. M. Midgley ◽  
K. R. Gruner
Keyword(s):  
Lower Limit ◽  
Healthy Subjects ◽  
Thyroid Dysfunction ◽  
Reference Range ◽  
Free Thyroxine ◽  
Reference Ranges ◽  
Free Triiodothyronine ◽  
Serum Free ◽  
Young Subjects ◽  
Age Range

SummaryAge-related trends in serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations were measured in 7248 euthyroid subjects (age-range 3 months to 106 years). 5700 were patients referred to hospitals for investigation of suspected thyroid dysfunction, but who were diagnosed euthyroid. 1548 were healthy blood donors (age-range 18-63 years) with no indication of thyroid dysfunction. FT4 concentrations were little affected by the age, the sex or the state of health of the subjects in either group. Serum FT3 concentrations were significantly affected by both age and health factors. The upper limit of the euthyroid reference range for young subjects up to 15 years was about 20% higher (10.4 pmol/1) than for adult subjects older than 25 years (8.8 pmol/1). The change in the upper limits typical of young subjects to that typical of adults occurred steadily over the decade 15–25 years. After this age, little further change occurred, especially in healthy subjects. Additionally, the lower limit of the euthyroid range for FT3 was extended by the inclusion in the reference group of patients referred to hospitals. Compared with the lower limit of the FT3 range for healthy subjects (5 pmol/1), the corresponding limit for referred subjects (young or adult) was 3.5–3.8 pmol/1. Broadening of the FT3 reference range was probably brought about by a significant number of patients in the hospital-referred group with the “1OW-T3 syndrome” of mild non-thyroidal illness. Accordingly, FT3 was inferior to FT4 in the discrimination of hypothyroidism, as FT4 was unaffected by this phenomenon. Effects of age and non-thyroidal illness on serum FT3 concentrations require great care when selecting subjects for a laboratory euthyroid reference range typical of the routine workload. Constraints on the choice of subjects for FT4 reference ranges are less stringent.

Lower Limit of the Possible Nucleate Pool-Boiling Enhancement by Surfactant Addition to Water

2002 ◽  
Vol 9 (3-4) ◽  
pp. 153-160 ◽  
Author(s):  
Yu-Min Yang ◽  
Chao-Yang Lin ◽  
Ming-Huei Liu ◽  
Jer-Ru Maa
Keyword(s):  
Lower Limit ◽  
Pool Boiling ◽  
Nucleate Pool Boiling ◽  
Boiling Enhancement

Skin exposure: requirements to methods determining active ingredient of pesticides in washings

2019 ◽  
pp. 43-48
Author(s):  
V. N. Rakitskii ◽  
N. E. Fedorova ◽  
I. V. Bereznyak ◽  
N. G. Zavolokina ◽  
L. P. Muhina
Keyword(s):  
Lower Limit ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Absorbed Dose ◽  
Ambient Air ◽  
Safety Coefficient ◽  
Limit Value ◽  
Calculated Risk ◽  
Nature Studies ◽  
Active Substances

The article presents results of studies exemplified by diquat on analysis concerning influence of lower limit value of quantitative assessment in washing sample for safety coefficient in exposure and in absorbed dose, if acting substance is absent in workplace ambient air samples and in dermal washings of workers. To control diquat in dermal washings, there is a method based on ion-pair liquid chromatography with ultraviolet detection (working wavelength 310 nm). To concentrate sample, cartridges for solid-phase extraction, containing ion exchange sorbent (Oasis MCX 6cc/500 mg), are used. Lower limit of assessment in washing sample — 0,15 micrograms. Experimentally set washing completeness is within range of 80–92%, standard deviation of repetition is 7,0% at most. The method created was tested in nature studies determining dermal exposure in workers subjected to 5 various preparations based on diquat dibromide when used for surface spraying from tractor and from aircraft. For lower limit of detection in washing sample (0,15 micrograms/washing), calculated risk value of exposure varied within 0,26–0,36; risk of absorbed dose was low — 0,23 (the allowable one ≤1). Findings are that present measuring methods which provide lower limit of detection 1 and 5 micrograms in washing sample could result in unallowable risk establishment even with absence of the substance in all samples of workplace air and dermal washings. The calculation formula suggested enables to give theoretic basis for requirements to lower limit of detecting active substances in dermal washing samples for evaluating risk of pesticides use in agriculture.

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