scholarly journals THE RHEOLOGY OF THE BLOOD. V

1945 ◽  
Vol 28 (6) ◽  
pp. 605-626 ◽  
Author(s):  
Eugene C. Bingham

A study has been made of those proteins which might offer exceptions to the law that the fluidity of a protein solution is a linear function of the volume concentration; viz., egg albumin, serum albumin, pseudoglobulin, euglobulin, gelatin, and sodium caseinogenate. Solutions of egg albumin below 20 per cent by weight obey the above law but somewhat below 30 per cent the fluidities begin to be too high, presumably due to the contribution to the fluidity made by the deformation of the particles as they come into contact, as the fluidity approaches zero. The fluidity of serum albumin solutions shows a similar behavior, being exceptional above 15 per cent in weight. Pseudoglobulin and euglobulin give fluidity-concentration curves (Fig. 4) which are linear up to about 2.5 per cent each in a total range of 20 and 14 per cent respectively. From this singular point both compounds show a second range which is linear. Pseudoglobulin is the only substance whose solutions seem to show a third linear range. We have also used the data of Chick and Martin for sodium caseinogenate and found evidence for two linear régimes. It is desirable at this time to call attention to the measurements of the flow of glycogen solutions by Botazzi and d'Errico (14) which in Fluidity and See PDF for Structure plasticity, page 207, are expressed in rhes. The data show two linear fluidity curves of different slopes. In this case it was definitely known that the data for each curve were measured with different viscometers which suggested the possibility of an error in viscometry entering in to confuse the issue. We have no suspicions as to the reliability of the data studied in this paper; we only wish to caution the readers that our hypotheses based on these data must be regarded with due reserve until confirmed. We have found a formula (11) based on the supposed linear relation between logarithmic fluidities and concentration which is convenient to use within the range, but close examination reveals that it does not reproduce the data for the higher concentrations at 25° nor does it permit extrapolation to pure water It is not realistic enough because it does not contemplate any change of régime in going from viscous to non-Newtonian or plastic flow. The formula does not apply to any other of the proteins studied in this paper nor to the great majority of proteins already reported as following the linear law. These are serious objections. We have therefore offered as an alternative a simple formula (24) according to which the fluidities are additive in the viscous régime. When the emulsoid particles approach close packing, they are deformed and this deformation contributes to the flow and the fluidity volume concentration curve is again linear. In fact, there may be one or more additional changes of régime.

2019 ◽  
Vol 15 ◽  
Author(s):  
Andaç Batur Çolak ◽  
Oğuzhan Yıldız ◽  
Mustafa Bayrak ◽  
Ali Celen ◽  
Ahmet Selim Dalkılıç ◽  
...  

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.


Author(s):  
Xiaozheng Bian ◽  
Jianping Huang ◽  
Lin Qiu ◽  
Chunyan Ma ◽  
Danli Xi

Abstract A new type of polyvinylidene fluoride (PVDF)/polymethyl methacrylate (PMMA) hollow fiber membrane (HFM) with five bores was prepared. The effects of Polyvinylpyrrolidone (PVP), β-cyclodextrine (β-CD), Polyethylene Glycol (PEG) and Polysorbate 80 (Tween 80) and their combinations on the PVDF/PMMA five-bore HFMs were investigated. The performance and fouling characteristics of five-bore HFMs for dyeing wastewater treatment were evaluated. Results indicated that adding 5wt.% PVP could increase the porosity and water flux of the membrane but decrease the bovine serum albumin (BSA) rejection rate. Adding 5wt.% β-CD significantly improved the tensile and rejection of the HFMs without showing effect on the increase of water flux. The characteristic of the HFMs with different additives combinations proved that the mixture of 5wt.% PVP and 1wt.% β-CD obtained the best membrane performance, with a pure water flux of 427.9 L/ m2·h, a contact angle of 25°, and a rejection to bovine serum albumin (BSA) of 89.7%. The CODcr and UV254 removal rates of dyeing wastewater treatment were 61.10% and 50.41%, respectively. No breakage or leakage points were found after 120d operation showing the reliable mechanical properties. We set the operating flux to 55 L/m2·h and cross flow rate to 10% which can effectively control membrane fouling.


1959 ◽  
Vol 14 (5) ◽  
pp. 323-327 ◽  
Author(s):  
Werner Heinzel ◽  
Ekkehard Kallee

1. The glomerular capsules of 8 Bombinata toads have been tapped. The glomerula have been found to excrete 0.035-0.15 μg of protein in about 0.11 μl of urine per hour, i. e., a 0.1 p.c. protein solution.2. Radioiodinated human serum albumin when injected intraperitoneally was excreted by the toad glomerula into the primary urine and resorbed back by the tubuli in principle in the same ways as toad serum proteins. However, the human albumin was excreted by the glomerula to a significantly larger extent than toad proteins.3. The concentration of both toad protein and 131I-labelled human albumin was approximately seven times lower in the bladder urine than in the primary urine.


Author(s):  
Yoshimichi Hagiwara ◽  
Yosuke Ohnishi ◽  
Daichi Yamamoto

Experiments have been conducted into the freezing of water flow and the aqueous solution flow of winter flounder antifreeze protein in a micro-channel of 0.15mm in height, 1.2mm in width and 21mm in length. The local temperature is measured with a sheathed thermocouple of 0.1mm in diameter. Nearly flat interfaces, parallel to the cooling sidewall of the channel, are observed in the case of pure water regardless of flow rate. On the other hand, serrated interfaces are observed in the case of protein solution flow regardless of flow rate. The decreasing rate of the temperature changes when the interface reaches the thermocouple. Around this instant, a slight increase in the temperature is observed due to supercooling release. In the case of local cooling, the interface becomes more serrated as the flow rate increases. This is because the interaction between the interface and the protein continuously approaching the interface due to the flow occurs more frequently with an increase in the flow rate.


2020 ◽  
Vol 9 (1) ◽  
pp. 13-23
Author(s):  
Samir M. Elshamy ◽  
Mohamed T. Abdelghany ◽  
M. R. Salem ◽  
O. E. Abdellatif

The aim of this research is to investigate experimentally the characteristics of the convective heat transfer and exergy analysis of pure water and water based Al2O3 nanofluid through helical coiled tubes (HCTs) and conical coiled tubes (CCTs) inside shell and coil heat exchangers. HCT and CCT fabricated with different coil torsions (λ) ranges from 0.0202 to 0.052 with different two angles (0° and 45°) while have the same curvature ratio (δ = 0.0564). The effects of mean coil torsion, the cone angle and nanoparticles volume concentration on the thermal performance were investigated. Results indicated that the overall heat transfer coefficient (Uov), convection heat transfer coefficient (ht), the tube side Nusselt number (Nut), effectiveness (ɛ) and exergy efficiency (ηex) of nanofluids are higher than those of the pure water at same flow condition, and this increase goes up with the increase in particle volume concentration (ϕ). The results also showed that Uov, ht, Nut, ɛ and ηex increases by decreasing the coil torsion from 0.052 to 0.0202. Correlations for Nut as a function of the investigated parameters are obtained.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Tshepo Duncan Dipheko ◽  
Kgabo Philemon Matabola ◽  
Kate Kotlhao ◽  
Richard M. Moutloali ◽  
Michael Klink

ZnO/PES composite membranes were fabricated by phase inversion method using DMAc as a solvent. The structure of ZnO was investigated using TEM, SEM, XRD, and TGA. TEM images of ZnO nanoparticles were well-defined, small, and spherically shaped with agglomerated nanoparticles particles of 50 nm. The SEM and XRD results were an indication that ZnO nanoparticles were present in the prepared ZnO/PES composites membranes. Contact angle measurements were used to investigate surface structures of the composite membranes. The amount of ZnO nanoparticles on PES membranes was varied to obtain the optimal performance of the composite membranes in terms of pure water flux, flux recovery, and fouling resistance using the protein bovine serum albumin (BSA) as a model organic foulant. The results showed that addition of ZnO to PES membranes improved the hydrophilicity, permeation, and fouling resistance properties of the membranes. Pure water flux increased from a low of 250 L/m2h for the neat membrane to a high of 410 L/m2h for the composite membranes. A high flux recovery of 80–94% was obtained for the composite membranes. The optimal performance of the composite membranes was obtained at 1.5 wt% of ZnO.


2020 ◽  
Vol 48 (3) ◽  
pp. 1155-1175
Author(s):  
Rahni HOSSAIN ◽  
Md A. RAHMAN ◽  
Md. K. J. RAFI ◽  
Tanvir A. SIDDIQUE ◽  
Abdullah A. NOMAN ◽  
...  

This research investigated pharmacological properties mainly the anti-inflammatory, anthelmintic, thrombolytic and anxiolytic potential of methanol extract of Syzygium samarangense (MESS) var. parviflorum. Anti-inflammatory action by bovine serum albumin, egg albumin denaturation and membrane stabilization, anthelmintic by live parasites, thrombolytic by clot lysis and anxiolytic by elevated plus maze (EPM) and light and dark box (LDB) tests were measured. The four targeted pharmacological properties were further justified using the most prevalent compounds, isolated from this plant, to be undergone for their pharmacokinetic property’s analyses, sitemap analyses and lignad-receptor interactions by computational models through SwissADME and Schrödinger, 2018 softwares against PDB 6COX, 6D6T, 1JFF receptors. MESS was found to display statistically significant (P < 0.05) inhibition of Bovine Serum albumin and Egg albumin denaturation compared to reference drug diclofenac sodium. Remarkable vermicidal effect on the paralysis and death of anthelmintic parasites was observed at MESS concentration 200 mg/dL. A nondescript clot lysis of MESS compared to streptokinase was evident in in vitro thrombolytic assay. MESS increased the number of times the animal crossed from one compartment to the other and the time spent in the brightly-lit chamber of the LDB. Three-methylchalcone derivatives out of seven MESS compounds were undertaken, based on cut off value and sitemap prediction score, for further ligand-receptor binding efficiency. All these three compounds showed promising docking score, glide emodel and glide energy against PDB 6COX, 6D6T and 1DDJ, plasmin proteins demonstrating the prospects of MESS to be materialized for anti-inflammatory, anthelmintic, and thrombolytic therapeutics with further clarification.


2020 ◽  
Vol 10 (5) ◽  
pp. 610-621
Author(s):  
Taliv Hussain ◽  
Mohammad T. Javed

Introduction: A numerical study is performed in which the friction factor and forced convection heat transfer is studied for Al2O3 nanoparticle dispersed in water as a base fluid. Methods: Four concentrations of nanofluids in the range of 0-2.5 vol% have been simulated. The Reynolds Number is varied in the range of 100-500 by varying inlet velocity. Cross flow of air is assumed over the pipe with air velocity of 2.2 m/s. Results: The results depict that the friction factor decreases with an increase in flow rate and increases with increase in volume concentration. The maximum deviation for friction factor obtained by simulation from that obtained using Darcy’s relation is about 21.5% for water. Nusselt number increases with increase in Reynolds Number and nanofluid volume concentration with a maximum of 7653.68 W/m2 at a nanoparticle concentration of 2.5% and Reynolds Number of 500. Heat transfer rate enhancement of upto 13.6% is obtained as compared to pure water. The maximum increase in Nusselt Number is about 13.07% for a nanoparticle concentration of 2.5%. Conclusion: The simulation results are compared with established relations obtained by other researchers and there is a good agreement in terms of trends obtained. The deviations from established relations are also depicted.


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