Transport Phenomena and Properties in Treelike Networks

2016 ◽  
Vol 68 (4) ◽  
Author(s):  
Peng Xu ◽  
Agus Pulung Sasmito ◽  
Boming Yu ◽  
Arun Sadashiv Mujumdar
Keyword(s):  
Transport Properties ◽  
Scaling Laws ◽  
Transport Phenomena ◽  
Transport Processes ◽  
Research Progress ◽  
Transport Systems ◽  
Transport Mechanisms ◽  
Branching Structures ◽  
Flow And Heat Transfer ◽  
Flow Heat

Treelike structures abound in natural as well as man-made transport systems, which have fascinated multidisciplinary researchers to study the transport phenomena and properties and understand the transport mechanisms of treelike structures for decades. The fluid flow and heat transfer in treelike networks have received an increasing attention over the past decade as the highly efficient transport processes observed in natural treelike structures can provide useful hints for optimal solutions to many engineering and industrial problems. This review paper attempts to present the background and research progress made in recent years on the transport phenomenon in treelike networks as well as technological applications of treelike structures. The subtopics included are optimization of branching structures, scaling laws of treelike networks, and transport properties for laminar flow, turbulent flow, heat conduction, and heat convection in treelike networks. Analytical expressions for the effective transport properties have been derived based on deterministic treelike networks, and the effect of branching parameters on the transport properties of treelike networks has also been discussed. Furthermore, numerical simulation results for treelike microchannel networks are presented as well. The proposed transport properties may be beneficial to understand the transport mechanisms of branching structures and promote the applications of treelike networks in engineering and industry.

scholarly journals Effect of serum proteins on sodium-linked transport processes in cultured kidney cells.

1995 ◽  
Vol 5 (11) ◽  
pp. 1964-1970
Author(s):  
S S Blumenthal ◽  
D L Lewand ◽  
P A Tipnis ◽  
J G Kleinman
Keyword(s):  
Amino Acid ◽  
Dextran Sulfate ◽  
Cultured Cells ◽  
Serum Proteins ◽  
Fluid Phase ◽  
Defined Medium ◽  
Transport Processes ◽  
Transport Systems ◽  
Heat Treated ◽  
Fluid Phase Endocytosis

The mechanism for increased Na+ retention in the nephrotic syndrome is unknown. To determine if Na+ transport systems in the proximal tubule might be affected by filtered proteins, mouse cortical tubule cells grown in defined medium were exposed to concentrations of bovine serum albumin (BSA) ranging from 0.01 to 0.5%. Activity of the Na(+)-glucose cotransporter, measured as Na(+)-dependent uptake of alpha-methylglucoside, increased progressively to a maximum of 2.3-fold above baseline (P < 0.001; N = 10). The increase in transporter activity was due to an increased Vmax, and the magnitude of the increase was inversely related to the basal cotransporter activity of the cultures. Increased cotransporter activity was detectable 6 h after exposure, was sustained for 24 h after cells were removed from an albumin-free medium, and was prevented by cycloheximide. Heat-treated BSA, fatty-acid and globulin-free BSA, and gamma-globulins were as effective at increasing Na(+)-glucose cotransporter activity as untreated Fraction V BSA. Dextran, dextran-sulfate, and amino acid supplements were ineffective. Neither protease inhibitors nor chloroquine added to an albumin-containing medium prevented increased alpha-methylglucoside uptake. Albumin did not change the rate of fluid-phase endocytosis in the cultured cells. Na(+)-amino acid cotransport and Na(+)-H+ exchange were either decreased or unchanged after BSA exposure. Exposing apical surfaces of cells grown on permeable membranes to BSA led to a greater increase in activity of the Na(+)-glucose cotransporter relative to controls than did exposing the basolateral surface (145 versus 89%; P < 0.05; N = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Shape difference of mud clasts depending on depositional facies: application of newly modified elliptic Fourier analysis to hybrid event beds

2020 ◽  
Vol 90 (10) ◽  
pp. 1410-1435
Author(s):  
Sojiro Fukuda ◽  
Hajime Naruse
Keyword(s):  
Fourier Analysis ◽  
Shape Analysis ◽  
Transport Processes ◽  
Transport Systems ◽  
Shape Parameters ◽  
Elliptic Fourier Analysis ◽  
Depositional Facies ◽  
Size And Shape ◽  
Muddy Sediments ◽  
Hybrid Event

ABSTRACT Hybrid event beds are the deposits from sediment gravity flows that change their rheological behavior through their passage, entraining muddy sediments and damping turbulence. Muddy facies of hybrid event beds are often associated with abundant mud clasts which show a wide variety of size and shape. The variation of clast occurrence in hybrid event beds is expected to preserve the information of entrainment and transport processes of muddy sediments in submarine density currents. However, previous analyses of hybrid event beds have focused on describing the overall clast occurrence rather than the statistical size and shape analyses because traditional shape parameters are incapable of characterizing the complex shape of mud clasts. Here, a new quantitative grain-shape analysis of mud clasts is conducted and allows visualization of the spatial variation of clast size and shape, which suggests the wide variety of origin and transport systems of entrained mud clasts. This new method revises the traditional elliptic Fourier analysis, substituting Fourier power spectra (FPS) for traditional elliptic Fourier descriptors to overcome the mirror-wise shape problem. Further, principal-component analysis is shown to capture significant shape attributes more effectively than traditional shape parameters. The proposed method is applied to mud clasts in sediment-gravity-flow deposits in the lower Pleistocene Otadai Formation, central Japan. Results imply that there are distinctive shape and size differences of mud clasts that are strongly associated with depositional facies rather than the distance from the source. The clasts have a higher angularity than other facies in the debrite intervals in hybrid event beds. It is also shown that clasts in sandy, structureless facies have different characteristics in shapes based on elongation and convexity compared to laminated facies. Comparison between different shape-analysis methods demonstrates that none of the traditional methods are able to visualize these trends as effectively as the method presented herein. These results highlight the importance of the quantitative shape analysis of sediment grains and the effectiveness of FPS-based elliptic Fourier analysis.

scholarly journals Transport Processes in Dense Stellar Plasmas

1994 ◽  
Vol 147 ◽  
pp. 394-419
Author(s):  
Naoki Itoh
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Liquid Metal ◽  
Neutron Stars ◽  
Transport Properties ◽  
Dense Matter ◽  
Transport Processes ◽  
Crystalline Lattice ◽  
Metal Phase ◽  
Current Status

AbstractTransport processes in dense stellar plasmas which are relevant to the interiors of white dwarfs and neutron stars are reviewed. The emphasis is placed on the accuracy of the numerical results. In this review we report on the electrical conductivity and the thermal conductivity of dense matter. The methods of the calculations are different for the liquid metal phase and the crystalline lattice phase. We will broadly review the current status of the calculations of the transport properties of dense matter, and try to give the best instructions available at the present time to the readers.

Transport characteristics of renal brush border Na(+)- and K(+)-dependent uridine carriers

1990 ◽  
Vol 258 (5) ◽  
pp. F1203-F1210 ◽  
Author(s):  
C. W. Lee ◽  
C. I. Cheeseman ◽  
S. M. Jarvis
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Positive Charge ◽  
Membrane Vesicles ◽  
Transport Processes ◽  
Transport Systems ◽  
Uridine Uptake ◽  
Renal Brush Border Membrane ◽  
Coupling Stoichiometry ◽  
Renal Brush Border

The uptake of uridine into rat renal brush-border membrane vesicles is mediated by Na(+)- and K(+)-dependent concentrative transport processes. At a 100 mM extravesicular cation concentration the apparent Km values were 9.7 +/- 4.2 and 28 +/- 5 microM, and Vmax values were 28 +/- 4 and 7 +/- 1 pmol.mg protein-1.s-1 for the Na(+)- and K(+)-dependent systems, respectively. Uracil, D-ribose, and D-glucose failed to inhibit the uptake processes, indicating that these carriers are specific for nucleosides. Other purines and pyrimidines inhibited uridine uptake competitively, although these two transport systems seem to favor adenosine and pyrimidines as permeants. Evidence is also given that transport is rheogenic, involving a net transfer of positive charge. The Na+:uridine and K+:uridine coupling stoichiometry was found to be 1:1 and 3:2, respectively. Both systems can also be driven by an anion gradient with apparent NO3- affinity (KNO3-) values of 42 +/- 13 and 163 +/- 54 mM for Na(+)- and K(+)-dependent systems, respectively.

Energy Transport Mechanisms in Nanofluids and Its Applications

2009 ◽  
Author(s):  
Yimin Xuan ◽  
Qiang Li
Keyword(s):  
Heat Transfer ◽  
Energy Transport ◽  
Transfer Mechanism ◽  
Thermal Engineering ◽  
Energy Transfer Mechanism ◽  
Transport Mechanisms ◽  
Thermal Systems ◽  
Flow And Heat Transfer ◽  
Solid Liquid ◽  
Suspended Nanoparticles

Nanofluid is a solid-liquid mixture consisting of solid nanoparticles or nanofibers with sizes typically of 1–100 nm suspended in liquid. Thermal conductivity and heat transfer performance of nanofluids is superior to those of the original pure carrier fluids because the suspended nanoparticles remarkably improve energy exchange capability of the suspensions. In the present paper, the investigations efforts cover microscopic and mesoscaled approachs for the heat transfer enhancement mechanism of the nanofluid, flow and heat transfer mechanism and the relevant control methods of the magnetic fluid by suspending magnetic nanoparticles in base fluids, and some applications of nanofluid on a variety of thermal systems in order to understand energy transfer mechanism of nanofluids and guide future applications of nanofluids to thermal engineering.

Numerical Optimization, Characterization, and Experimental Investigation of Additively Manufactured Communicating Microchannels

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Kathryn L. Kirsch ◽  
Karen A. Thole
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Pressure Loss ◽  
Reynolds Numbers ◽  
Transport Systems ◽  
Optimized Design ◽  
Internal Cooling ◽  
Natural Systems ◽  
Flow And Heat Transfer ◽  
Successful Replication

The degree of complexity in internal cooling designs is tied to the capabilities of the manufacturing process. Additive manufacturing (AM) grants designers increased freedom while offering adequate reproducibility of microsized, unconventional features that can be used to cool the skin of gas turbine components. One such desirable feature can be sourced from nature; a common characteristic of natural transport systems is a network of communicating channels. In an effort to create an engineered design that utilizes the benefits of those natural systems, the current study presents wavy microchannels that were connected using branches. Two different wavelength baseline configurations were designed; then each was numerically optimized using a commercial adjoint-based method. Three objective functions were posed to (1) minimize pressure loss, (2) maximize heat transfer, and (3) maximize the ratio of heat transfer to pressure loss. All baseline and optimized microchannels were manufactured using laser powder bed fusion (L-PBF) for experimental investigation; pressure loss and heat transfer data were collected over a range of Reynolds numbers. The AM process reproduced the desired optimized geometries faithfully. Surface roughness, however, strongly influenced the experimental results; successful replication of the intended flow and heat transfer performance was tied to the optimized design intent. Even still, certain test coupons yielded performances that correlated well with the simulation results.

Experimental Investigation of Flow and Heat Transfer Characteristics Using Thermo-Sensitive Magnetic Fluid in a Mini-Channel

2007 ◽  
Author(s):  
Koji Fumoto ◽  
Masahiro Ikegawa
Keyword(s):  
Heat Transfer ◽  
Magnetic Fluid ◽  
Flow Characteristics ◽  
Force Convection ◽  
Transport Systems ◽  
Magnetic Characteristics ◽  
Flow And Heat Transfer ◽  
Zn Ferrite ◽  
Mini Channels ◽  
Increasing Temperature

In the present study, the flow characteristics and heat transfer of a thermo-sensitive magnetic fluid, which is a multiphase-flow material, were investigated experimentally. Heat transport systems using magnetic fluids have been proposed by several researchers, but miniature devices of this type have not yet been developed. The mini-channels considered herein have a depth of 500 μm, with the nominal channel width being five times the width. The channel device was constructed from a Teflon tube. The operation of the device is based on the thermo-magnetic characteristics of the fluid, a suspension of Mn-Zn ferrite particles in kerosene, the magnetization of which is known to decrease with increasing temperature. The experimental parameters were magnetic force, the position of the magnet, and the temperature of the magnetic fluid. The experimental results indicated that force convection based on the magnetic characteristics of the fluid in the mini-channel exhibited excellent cooling performance. In particular, the observed variations in the flow patterns were compared with the results of a boundary layer of the flow velocity in the pipe, which is generally known. Furthermore, it was found that the flow characteristic of the thermo-sensitive magnetic fluid was strongly dependent on the magnetic condition, such as the force and the position.

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