scholarly journals Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4599
Author(s):  
Jacek Kropiwnicki ◽  
Mariusz Furmanek ◽  
Andrzej Rogala
Keyword(s):  
Iterative Procedure ◽  
Computational Algorithm ◽  
Water System ◽  
Typical Situation ◽  
Calculation Step ◽  
Analytical Work ◽  
Medium Flow ◽  
Flow Through ◽  
Process Gases ◽  
Basic Equations

The paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically modified during the warming-up process. A typical situation, when such a modification is processed, is the regulation of the medium flow through two-way or three-way valves or applying additional heat source. Moreover, the presented method does not require the transformation of the differential equations, describing the operation of individual elements, into a linear form, which significantly facilitates analytical work and makes it more flexible. The example of analysis of the operation of water installation used for controlling temperature of the process gases in a chemical installation shows the functionality and flexibility of the method. The adopted calculation schematics enable changing the direction of the heat flow while the heat exchanger is in operation. Additionally, the sequence of calculation processed in modules describing operation of installation elements is elective (there is no situation that output parameters from one element are used as input parameters for other element in the same calculation step).

Lactate as substrate for glycogen resynthesis after exercise

1987 ◽  
Vol 62 (6) ◽  
pp. 2237-2240 ◽  
Author(s):  
R. W. Stevenson ◽  
D. R. Mitchell ◽  
G. K. Hendrick ◽  
R. Rainey ◽  
A. D. Cherrington ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Recovery Period ◽  
Control Level ◽  
Lactate Concentration ◽  
Perfusion Medium ◽  
Muscle Lactate ◽  
Arterial Lactate ◽  
Medium Flow ◽  
Flow Through ◽  
Lactate Levels

Muscle glycogen levels in the perfused rat hemicorpus preparation were reduced two-thirds by electrical stimulation plus exposure to epinephrine (10(-7) M) for 30 min. During the contraction period muscle lactate concentrations increased from a control level of 3.6 +/- 0.6 to a final value of 24.1 +/- 1.6 mumol/g muscle. To determine whether the lactate that had accumulated in muscle during contraction could be used to resynthesize glycogen, glycogen levels were determined after 1–3 h of recovery from the contraction period during which time the perfusion medium (flow-through system) contained low (1.3 mmol/l) or high (10.5 or 18 mmol/l) lactate concentrations but no glucose. With the low perfusate lactate concentration, muscle lactate levels declined to 7.2 +/- 0.8 mumol/g muscle by 3 h after the contraction period and muscle glycogen levels did not increase (1.28 +/- 0.07 at 3 h vs. 1.35 +/- 0.09 mg glucosyl U/g at end of exercise). Lactate disappearance from muscle was accounted for entirely by output into the venous effluent. With the high perfusate lactate concentrations, muscle lactate levels remained high (13.7 +/- 1.7 and 19.3 +/- 2.0 mumol/g) and glycogen levels increased by 1.11 and 0.86 mg glucosyl U/g, respectively, after 1 h of recovery from exercise. No more glycogen was synthesized when the recovery period was extended. Therefore, it appears that limited resynthesis of glycogen from lactate can occur after the contraction period but only when arterial lactate concentrations are high; otherwise the lactate that builds up in muscle during contraction will diffuse into the bloodstream.

scholarly journals Contamination of Trichloroethylene in Drinking Water System and Its Degradation

2012 ◽  
Vol 3 ◽  
pp. 13-17 ◽  
Author(s):  
Devi Lal Adhikari ◽  
Chikashi Sato ◽  
Shobha Kanta Lamichhane
Keyword(s):  
Drinking Water ◽  
Titanium Dioxide ◽  
Ultraviolet Light ◽  
Water System ◽  
Ultrasonic Waves ◽  
Produce Water ◽  
Drinking Water Standard ◽  
Drinking Water System ◽  
Flow Through ◽  
System Water

Photolysis and sonolysis of trichloroethylene (TCE) in water was investigated using a cup-horn, flow-through reactor system. Water containing titanium dioxide was deliberately contaminated with TCE. These solutions were irradiated with ultraviolet light (UV) and ultrasonic waves (US). The decrease in the TCE concentration was observed in water under both US and UV treatments. Present findings declare that the use of UV and US decreased the TCE concentration. With the reactor specifications used, the photolysis and sonolysis processes can produce water meeting the drinking water standard (MCLs of 5?g/L) for TCE.The Himalayan PhysicsVol. 3, No. 32012Page : 13-17

scholarly journals A MODEL SYSTEM FOR DETERMINING CHEMICAL MOVEMENT THROUGH GOLF COURSE GREENS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 588d-588
Author(s):  
Albert E. Smith ◽  
Will Corley
Keyword(s):  
Polyvinyl Chloride ◽  
Coefficient Of Variation ◽  
Irrigation System ◽  
Water System ◽  
Model System ◽  
Golf Course ◽  
Exit Port ◽  
Flow Through ◽  
Time Periods ◽  
Predetermined Time

Lysimeters were developed in the greenhouse for simulating golf course greens with `Tifdwarf' bermudagrass and `Penncross' bentgrass overlying USGA specified rooting substratum. The lysimeters were constructed by subtending wooden flats containing turfgrass (38 × 38 × 14 cm deep) with polyvinyl chloride tubes (15 cm diam. × 52 cm deep) containing USGA-recommended rooting mixture for each turfgrass. The base of the tubes was capped with a closure containing an exit port for collecting the effluent drainage. An automatic irrigation system was developed by mounting flat fan nozzles on a cable driven roller 55 cm above the grass sod. The automatic water system is calibrated to irrigate at a rate of 0.1 cm min-1 for predetermined time-periods and volumes. The water flow through the lysimeters is uniform with a coefficient of variation less than 10% for 36 lysimeters. Data on chemical movement following treatment with three herbicides and weekly applications of fertilizer will be presented.

scholarly journals solutions of the CW equation for flow friction

2017 ◽  
Author(s):  
Dejan Brkić
Keyword(s):  
Fluid Flow ◽  
Friction Factor ◽  
Explicit Form ◽  
Iterative Procedure ◽  
Lambert W Function ◽  
Explicit Formulas ◽  
Flow Friction ◽  
Transcendental Functions ◽  
Flow Through

The empirical Colebrook–White (CW) equation belongs to the group of transcendental functions. The CW function is used for the determination of hydraulic resistances associated with fluid flow through pipes, flow of rivers, etc. Since the CW equation is implicit in fluid flow friction factor, it has to be approximately solved using iterative procedure or using some of the approximate explicit formulas developed by many authors. Alternate mathematical equivalents to the original expression of the CW equation, but now in the explicit form developed using the Lambert W-function, are shown (with related solutions). The W-function is also transcendental, but it is used more general compared with the CW function. Hence, the solution to the W-function developed by mathematicians can be used effectively for the CW function which is of interest only for hydraulics.

Physiological disturbances in rainbow trout (Salmo gairdneri) during acid and aluminum exposures in soft water of two calcium concentrations

1989 ◽  
Vol 67 (2) ◽  
pp. 314-324 ◽  
Author(s):  
Richard C. Playle ◽  
Greg G. Goss ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Water System ◽  
Respiratory Acidosis ◽  
Carbon Dioxide Tension ◽  
Soft Water ◽  
Cell Swelling ◽  
Salmo Gairdneri ◽  
Flow Through ◽  
Respiratory Gases ◽  
Respiratory Toxicity

Rainbow trout (Salmo gairdneri) fitted with dorsal aortic cannulae were exposed in a flow-through soft water system to three acidities (pH 5.2, 4.8, or 4.4) and two concentrations of Ca (45 or 410 μequiv.∙L−1), in the presence (105 μg∙L−1) or absence of Al. Blood was sampled for respiratory gases, ions, metabolites, and hematology before and at 4, 18, 28, 42, and 66 h exposure. Two toxic mechanisms of Al and acidity were seen: (i) ionoregulatory toxicity, which was caused by Al at pH 5.2 and 4.8 and by acidity at pH 4.4, and (ii) respiratory toxicity, which was caused solely by Al, and was greatest at higher pH. Ionoregulatory toxicity involved decreases in plasma Na+ and Cl−, red cell swelling, and hemoconcentration. Respiratory toxicity involved reduced blood oxygen tension, elevated blood carbon dioxide tension, and increases in blood lactate. Blood acidosis was a combination of respiratory acidosis (due to CO2 accumulation in the blood; higher pH exposures) and metabolic acidosis (probably due to differential Na+ and Cl− loss into the external, acidic environment; lower pH exposures). Higher water Ca reduced ionoregulatory disturbances due to acidity alone but not those due to Al at higher pH. Higher water Ca also reduced respiratory disturbances at lower pH but not at higher pH. The results are discussed with reference to the chemistry of Al and changes in the gill epithelium associated with acid and Al exposure.

Energy Use and Performance of a New Variable Primary-Flow Chilled Water System

Solar Energy ◽  
2005 ◽  
Author(s):  
Li Song ◽  
Ik-Seong Joo ◽  
Mingsheng Liu
Keyword(s):  
Pump Power ◽  
Water Supply ◽  
Water Flow ◽  
Water System ◽  
Variable Flow ◽  
Chilled Water ◽  
Flow Through ◽  
Compressor Power ◽  
Cooling Coil

The traditional chilled water loop has been designed as a primary/secondary (P/S) system for several years. The primary loop maintains constant chilled water flow through the evaporator, and the secondary loop is designed as a variable flow system in response to variations in building cooling load. The primary/secondary design separates the chiller operation from the building load requirements. This design principle has been working adequately for old chillers that require constant chilled water flow to achieve stable chiller performance. However, these chillers operate inefficiently and consume unnecessary pump power. In recent years, the chiller industry has begun the use of variable water flow through evaporators. Significant energy savings can be achieved by using the variable flow principle. This paper compares the P/S system with variable chilled water system and also proposes an innovative solution: chilled water supply temperature reset to maintain the minimum chilled water flow and eliminate by-pass water flow. The energy consumption models including pump power and chiller compressor power improvement are presented to simulate the energy performance of two systems. ASHRAE detailed cooling coil models are also adopted to simulate the cooling coil discharge air humidity in order to verify the impacts of the chilled water supply temperature reset. Finally, a case study building demonstrates experimental results. Up to 10% pump and compressor power saving is demonstrated by simulations and the case study.

Post-larval recruitment of blacklip abalone (Haliotis rubra) on artificial collectors in southern Tasmania

1995 ◽  
Vol 46 (3) ◽  
pp. 531 ◽  
Author(s):  
WJ Nash ◽  
JC Sanderson ◽  
J Bridley ◽  
S Dickson ◽  
B Hislop
Keyword(s):  
Sea Water ◽  
Larval Settlement ◽  
Water System ◽  
Early Spring ◽  
Larval Abundance ◽  
Second Phase ◽  
Larval Recruitment ◽  
Stage Process ◽  
Flow Through ◽  
Haliotis Rubra

Recruitment rates of blacklip abalone (Haliotis rubra) post-larvae were measured at fortnightly intervals for a year in southern Tasmania on larval collectors made of transparent, corrugated plastic. The settlement plates were conditioned prior to use in a flow-through sea-water system in a two-stage process. A film of diatoms (mainly Nitzschia and Navicula species) was first established on the plates, which were then grazed by juvenile H. rubra. This allowed second-phase algae (principally Myrionema species) to become established. The plates were then periodically deployed at a depth of ~7 m. Larval settlement occurred mainly during the austral winter and early spring. A peak settlement rate of 1408 post-larvae per collector (2347 post-larvae m-2) occurred in mid August. Methods of measuring larval or immediate post-larval abundance are reviewed with regard to their use in the assessment and management of abalone fisheries.

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