scholarly journals Turbulence characteristics of large factory building and its influence on airship transport process

2021 ◽  
Vol 1985 (1) ◽  
pp. 012054
Author(s):  
Yuan Liu ◽  
Hu Ye ◽  
Yongdong Zhang ◽  
Li Zhang ◽  
Min Li ◽  
...  
Keyword(s):  
Transport Process ◽  
Turbulence Characteristics ◽  
Factory Building

EFFICACY OF SALICYLIC AND ASCORBIC ACIDS TO REDUCE THE EFFECT OF TRANSPORT STRESS ON LIVE WEIGHT, SOME BLOOD CHARACTERISTICS AND INTESTINAL VILLI OF BROILER CHICKENS

2020 ◽  
Vol 51 (4) ◽  
pp. 1074-1081
Author(s):  
Al obaydy & et al.
Keyword(s):  
Ascorbic Acid ◽  
Drinking Water ◽  
Transport Process ◽  
Live Weight ◽  
Cholesterol Concentration ◽  
Control Treatment ◽  
Intestinal Villi ◽  
Slaughter House ◽  
Transport Stress ◽  
Financial Losses

This experiment was conducted and aimed to reducing mortality and losing the weight of birds transported to the slaughter house through reducing or Transport stress removal and thus to reduce financial losses. 150 birds used almost equal weights that were divided into three treatment groups and by five replicates for each treatment is control treatment (T1) without giving anything and treatment with salicylic acid concentration 1 g / liter of drinking water (T2) and treatment with ascorbic acid (T3) concentration 0.5 g / Liter of drinking water provided 24 hours before its transport. The transport process resulted in a highly significant decrease (P ≤ 0.01) in body weight in treatment T1 as it reached 4.66%, while it reached 1.68 and 1.09% in treatment T2 and T3, respectively. The transport process led to an increase in body temperature, H / L ratio, the concentration of glucose, aspartate transaminase (AST) and alanine transaminase (ALT) in the blood serum, as the transport process led to a very significant decrease (P ≤ 0.01) in the cholesterol concentration, Uric acid, intestinal villi length and crypts depth. T2 and T3 treatments showed their ability to reduce transport stress, especially T3, where they outperformed T1 in most traits. It is concluded from the study that adding ascorbic acid by 0.5 g / L drinking water 24 hours before transporting the chicks to the slaughter house reduces the transport stress and lessen financial losses, so it is recommended to use it.

scholarly journals Calixresorcin[4]arene-Mediated Transport of Pb(II) Ions Through Polymer Inclusion Membrane

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 285
Author(s):  
Joanna Konczyk ◽  
Wojciech Ciesielski
Keyword(s):  
Activation Energy ◽  
Transport Process ◽  
Optimal Conditions ◽  
Inclusion Membrane ◽  
Polymer Inclusion Membrane ◽  
Membrane Effect ◽  
Feed Phase ◽  
Ion Carrier ◽  
Feed Effect ◽  
Nitrate Solutions

A facilitated transport of Pb(II) through polymer inclusion membrane (PIM) containing 1,8,15,22-tetra(1-heptyl)-calixresorcin[4]arene and its tetra- and octasubstituted derivatives containing phosphoryl, thiophosphoryl or ester groups as an ion carrier was investigated. The efficiency of Pb(II) removal from aqueous nitrate solutions was considered as a function of the composition of membrane (effect of polymer, plasticizer, and carrier), feed (effect of initial metal concentration and presence of other metal ions) and stripping phases, and temperature of the process conducting. Two kinetic models were applied for the transport description. The highest Pb(II) ions removal efficiency was obtained for the membrane with tetrathiophosphorylated heptyl-calixresorcin[4]arene as an ion carrier. The activation energy value, found from Eyring plot to be equal 38.7 ± 1.3 kJ/mol, suggests that the transport process is controllable both by diffusion and chemical reaction. The competitive transport of Pb(II) over Zn(II), Cd(II), and Cr(III) ions across PIMs under the optimal conditions was also performed. It was found that the Cr(III) ions’ presence in the feed phase disturb effective re-extraction of Pb(II) ions from membrane to stripping phase. Better stability of PIM-type than SLM-type membrane was found.

scholarly journals Turbulence Characteristics Across a Range of Idealized Urban Canopy Geometries

2021 ◽  
Author(s):  
Lewis P. Blunn ◽  
Omduth Coceal ◽  
Negin Nazarian ◽  
Janet F. Barlow ◽  
Robert S. Plant ◽  
...  
Keyword(s):  
Momentum Flux ◽  
Mixing Layer ◽  
Urban Canopy ◽  
Turbulence Closure ◽  
Length Scale ◽  
Good Representation ◽  
Mixing Length ◽  
Turbulence Characteristics ◽  
First Order ◽  
Turbulent Momentum

AbstractGood representation of turbulence in urban canopy models is necessary for accurate prediction of momentum and scalar distribution in and above urban canopies. To develop and improve turbulence closure schemes for one-dimensional multi-layer urban canopy models, turbulence characteristics are investigated here by analyzing existing large-eddy simulation and direct numerical simulation data. A range of geometries and flow regimes are analyzed that span packing densities of 0.0625 to 0.44, different building array configurations (cubes and cuboids, aligned and staggered arrays, and variable building height), and different incident wind directions ($$0^\circ $$ 0 ∘ and $$45^\circ $$ 45 ∘ with regards to the building face). Momentum mixing-length profiles share similar characteristics across the range of geometries, making a first-order momentum mixing-length turbulence closure a promising approach. In vegetation canopies turbulence is dominated by mixing-layer eddies of a scale determined by the canopy-top shear length scale. No relationship was found between the depth-averaged momentum mixing length within the canopy and the canopy-top shear length scale in the present study. By careful specification of the intrinsic averaging operator in the canopy, an often-overlooked term that accounts for changes in plan area density with height is included in a first-order momentum mixing-length turbulence closure model. For an array of variable-height buildings, its omission leads to velocity overestimation of up to $$17\%$$ 17 % . Additionally, we observe that the von Kármán coefficient varies between 0.20 and 0.51 across simulations, which is the first time such a range of values has been documented. When driving flow is oblique to the building faces, the ratio of dispersive to turbulent momentum flux is larger than unity in the lower half of the canopy, and wake production becomes significant compared to shear production of turbulent momentum flux. It is probable that dispersive momentum fluxes are more significant than previously thought in real urban settings, where the wind direction is almost always oblique.

scholarly journals Flow Turbulence Characteristics and Mass Transport in the Near-Wake Region of an Aquaculture Cage Net Panel

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 294
Author(s):  
Dongdong Shao ◽  
Li Huang ◽  
Ruo-Qian Wang ◽  
Carlo Gualtieri ◽  
Alan Cuthbertson
Keyword(s):  
Mass Transport ◽  
Near Field ◽  
Lateral Spreading ◽  
Wake Flow ◽  
Wake Region ◽  
Near Wake ◽  
Turbulence Characteristics ◽  
Macro Scale ◽  
Flow Turbulence ◽  
Fish Cages

Cage-based aquaculture has been growing rapidly in recent years. In some locations, cage-based aquaculture has resulted in the clustering of large quantities of cages in fish farms located in inland lakes or reservoirs and coastal embayments or fjords, significantly affecting flow and mass transport in the surrounding waters. Existing studies have focused primarily on the macro-scale flow blockage effects of fish cages, and the complex wake flow and associated near-field mass transport in the presence of the cages remain largely unclear. As a first step toward resolving this knowledge gap, this study employed the combined Particle Image Velocimetry and Planar Laser Induced Fluorescence (PIV-PLIF) flow imaging technique to measure turbulence characteristics and associated mass transport in the near wake of a steady current through an aquaculture cage net panel in parametric flume experiments. In the near-wake region, defined as ~3M (mesh size) downstream of the net, the flow turbulence was observed to be highly inhomogeneous and anisotropic in nature. Further downstream, the turbulent intensity followed a power-law decay after the turbulence production region, albeit with a decay exponent much smaller than reported values for analogous grid-generated turbulence. Overall, the presence of the net panel slightly enhanced the lateral spreading of the scalar plume, but the lateral distribution of the scalar concentration, concentration fluctuation and transverse turbulent scalar flux exhibited self-similarity from the near-wake region where the flow was still strongly inhomogeneous. The apparent turbulent diffusivity estimated from the gross plume parameters was found to be in reasonable agreement with the Taylor diffusivity calculated as the product of the transverse velocity fluctuation and integral length scale, even when the plume development was still transitioning from a turbulent-convective to turbulent-diffusive regime. The findings of this study provide references to the near-field scalar transport of fish cages, which has important implications in the assessment of the environmental impacts and environmental carrying capacity of cage-based aquaculture.

Low Frequency Noise from a Big Building Due to Oscillatory Forces of a Machine

1982 ◽  
Vol 1 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Niichi Nishiwaki ◽  
Noboru Fujio ◽  
Takuji Mori
Keyword(s):  
Low Frequency ◽  
Ground Vibration ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Ground Acceleration ◽  
Building Frames ◽  
Acceleration Level ◽  
Residential District ◽  
Factory Building ◽  
Grinding Mill

People living in houses near a big factory complained about chattering of glass windows. At one of these houses, the SPL of low frequency noise was about 66 dB at 5.5 Hz and ground acceleration level was about 40 dB at 9 Hz in the horizontal direction. (0 dB acceleration = 10−5 m/s2). We found that the noise and ground vibration were caused by a big grinding mill in the factory, because both SPL and acceleration level at the residential district were considerably decreased when the mill was not in operation. We also confirmed that low frequency noise was not transmitted from the grinding mill directly, but was due to the resonant vibration of walls of the factory building. Two ideas are studied here to suppress the noise, one of which is to isolate the vibration of the grinding mill at its foundation, and the other is to improve the stiffness of the building frames to stop the wall vibration. As a result of the study, the latter method to increase the stiffness of the building was adopted. The SPL of low frequency noise near the wall was decreased.

scholarly journals Lithium abundances in late main sequence stars. The case of the hyades

1984 ◽  
Vol 105 ◽  
pp. 529-531
Author(s):  
A. Baglin ◽  
P.J. Morel
Keyword(s):  
Low Temperature ◽  
Transport Process ◽  
Main Sequence ◽  
Light Elements ◽  
Main Sequence Stars

It is well known that light elements like lithium are good indicators of the hydrodynamical behaviour of the outerlayers of the stars. As they are nuclearly destroyed at low temperature, i.e. close to the surface, their surface abundances reflect the nature of the transport process at work between the photosphere and the nuclear destruction region.

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