scholarly journals Effect of Isomer Composition of Hydroxy Terminated Polybutadiene (HTPB) in Low Shear Flow Behavior (Efek dari Komposisi Isomer dari Hydroxy Terminated Polybutadiene (HTPB) terhadap Sifat Alir dalam Geseran Rendah)

2020 ◽  
Vol 18 (2) ◽  
pp. 117
Author(s):  
Afni Restasari ◽  
Luthfia Hajar Abdillah ◽  
Retno Ardianingsih ◽  
Rika Suwana Budi
Keyword(s):  
Flow Resistance ◽  
Flow Behavior ◽  
Shear Thickening ◽  
Trans Isomers ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Infra Red ◽  
Ft Ir ◽  
Filled Composite ◽  
Low Shear

HTPB is the ultimate component of matrix builder for high-filled composite materials. Flow behavior of HTPB in low shear is crucial in casting the composite. Considering the characteristics of hydrocarbon, this work aims to investigate the effect of microstructure composition of HTPB on its flow behavior. In this work, HTPB with different composition of 1,4-cis, 1,2-vinyl and 1,4-trans microstructures were used. Fourier-Transform Infra-Red spectroscopy (FT-IR) was used to determine the composition. It was calculated as a ratio of peak area of 710, 910 and 970 cm-1 for 1,4-cis, 1,2-vinyl, 1,4-trans isomers respectively. Viscosity was measured using a rotational viscometer at various low shear rates. It is found that HTPB with high 1,2-vinyl/1,4-trans isomers shows shear thickening behaviour, distinguished significantly from Newtonian flow of the others. It is suggested that mechanism of shear thickening involves a certain configuration of 1,2-vinyl and 1,4-trans isomers that builds different degrees of flow resistance from one to other shear layers. The configuration and flow resistance changes among layers as shear increases.

Non-Newtonian Flow Behavior in Microchannels for Emulsion Formation

2006 ◽  
Author(s):  
Ravi Arora ◽  
Eric Daymo ◽  
Anna Lee Tonkovich ◽  
Laura Silva ◽  
Rick Stevenson ◽  
...  
Keyword(s):  
Shear Stress ◽  
Pressure Drop ◽  
Wall Shear Stress ◽  
Power Law ◽  
Flow Behavior ◽  
Scale Up ◽  
High Wall Shear Stress ◽  
Shear Rates ◽  
Wall Shear ◽  
Low Shear

Emulsion formation within microchannels enables smaller mean droplet sizes for new commercial applications such as personal care, medical, and food products among others. When operated at a high flow rate per channel, the resulting emulsion mixture creates a high wall shear stress along the walls of the narrow microchannel. This high fluid-wall shear stress of continuous phase material past a dispersed phase, introduced through a permeable wall, enables the formation of small emulsion droplets — one drop at a time. A challenge to the scale-up of this technology has been to understand the behavior of non-Newtonian fluids under high wall shear stress. A further complication has been the change in fluid properties with composition along the length of the microchannel as the emulsion is formed. Many of the predictive models for non-Newtonian emulsion fluids were derived at low shear rates and have shown excellent agreement between predictions and experiments. The power law relationship for non-Newtonian emulsions obtained at low shear rates breaks down under the high shear environment created by high throughputs in small microchannels. The small dimensions create higher velocity gradients at the wall, resulting in larger apparent viscosity. Extrapolation of the power law obtained in low shear environment may lead to under-predictions of pressure drop in microchannels. This work describes the results of a shear-thinning fluid that generates larger pressure drop in a high-wall shear stress microchannel environment than predicted from traditional correlations.

scholarly journals Reversible shear thickening at low shear rates of electrorheological fluids under electric fields

2011 ◽  
Vol 83 (1) ◽  
Author(s):  
Yu Tian ◽  
Minliang Zhang ◽  
Jile Jiang ◽  
Noshir Pesika ◽  
Hongbo Zeng ◽  
...  
Keyword(s):  
Electric Fields ◽  
Shear Thickening ◽  
Electrorheological Fluids ◽  
Shear Rates ◽  
Low Shear

Viscosity of Some Contemporary Contrast Media before and after Mixing with Whole Blood

1992 ◽  
Vol 33 (6) ◽  
pp. 600-605 ◽  
Author(s):  
Ö. Smedby
Keyword(s):  
Contrast Media ◽  
Shear Viscosity ◽  
Whole Blood ◽  
Blood Rheology ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Before And After ◽  
Low Shear Viscosity ◽  
Contrast Medium Concentration ◽  
Low Shear

The viscosity of 7 contrast media was measured using a rotational viscometer. When solutions with similar iodine concentrations were compared, the highest viscosities were found for the nonionic dimers iodixanol and iotrolan, the lowest for diatrizoate, iopamidol, and iopromide, and intermediate values for iohexol and ioxaglate. The viscosity of iohexol and ioxaglate was found to vary linearly with temperature and quadratically with concentration. Whole-blood viscosity was measured for 5 subjects at high and low shear rates before and after mixing with contrast media in various proportions. Low-shear viscosity was found to decrease and high-shear viscosity to increase with contrast medium concentration. It is concluded that the contrast media currently used may affect blood rheology less than previous agents, despite their higher viscosity.

Milk acetone determination by the photometrical method after microdiffusion and via FT infra-red spectroscopy

2011 ◽  
Vol 28 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Oto Hanuš ◽  
Václava Genčurová ◽  
Yunhai Zhang ◽  
Pavel Hering ◽  
Jaroslav Kopecký ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Indirect Method ◽  
Geometric Mean ◽  
Mid Infrared ◽  
Subclinical Ketosis ◽  
Infra Red ◽  
Variation Range ◽  
Ft Ir ◽  
Infrared Method ◽  
Photometrical Method

Milk acetone determination by the photometrical method after microdiffusion and via FT infra-red spectroscopyMilk acetone (AC) and betahydroxybutyrate (BHB) are important indicators of the energy metabolism of cows (ketosis occurrence) and an effective method for their determination, with reliable results, is of great importance. The goal of this work was to investigate the infrared method MIR-FT in terms of its calibration for milk AC and to develop a usable procedure. The microdiffusion photometric (485 nm; Spekol 11) method was used with salicylaldehyde as a reference (Re) and mid infrared spectroscopy FT (MIR-FT: Lactoscope FT-IR, Delta; MilkoScan FT 6000, M-Sc) as an indirect method. The acetone addition to milk had no recovery using MIR-FT (Delta). The reference AC set must have acceptable statistics for good MIR-FT calibration (M-Sc) and they were: 10.1 ± 9.74 at a geometric mean of 7.26 mg l-1, and a variation range from 1.98 to 33.66 mg l-1. The AC correlation between Re and MIR-FT (Delta) was low at 0.32 (P>0.05 but the Log AC relationship between Re and MIR-FT (M-Sc) was markedly better at 0.80 (P<0.01). The conversion of >10 mg l-1 as an AC subclinical ketosis limit could be > -0.80 (feedback 0.158 mmol l-1 = 9.25 mg l-1) and > -1.66. This could be important for ketosis monitoring (using M-Sc).

A study on using expanded perlite with hydroxyapatite: Reinforced bio-composites

2021 ◽  
pp. 095441192199656
Author(s):  
Erdoğan Karip ◽  
Mehtap Muratoğlu
Keyword(s):  
Body Fluid ◽  
Xrd Analysis ◽  
Cold Isostatic Pressing ◽  
Expanded Perlite ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
X Ray ◽  
Infra Red ◽  
Ft Ir

People are exposed to different kinds of diseases or various accidents in life. Hydroxyapatite (HA) has been widely employed for bone treatment applications. In this study, HA was extracted from sheep bones. Bio-composites were doped with 1, 5, and 10 wt.% of expanded perlite and 5 wt.% of ZrO2–MgO-P2O5. The bio-composites were prepared by the cold isostatic pressing method (250 MPa) and sintered at 900°C for 1 h. In order to evaluate the characteristics of the bio-composites, microhardness, density, X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses were carried out on them. Additionally, the specimens whose characteristics were determined were kept in synthetic body fluid (SBF), and their in vitro behavior was examined. As a result, it was observed that microhardness increased as both the weight and the grain size of the expanded perlite were increased. Calcium silicate, tri-calcium phosphate, and hydroxyapatite were observed in the XRD analysis of all samples, and the formation of apatite structures was increased by addition of ZrO2–MgO–P2O5.

The Characteristic Evaluation of Hydroxyapatite Powders Synthesized from CaCO3 Refined from Oyster Shell and H3PO4

2006 ◽  
Vol 118 ◽  
pp. 639-644
Author(s):  
Hye Sung Kim ◽  
Su Chak Ryu
Keyword(s):  
Bone Density ◽  
Inductively Coupled Plasma ◽  
Oyster Shell ◽  
Atomic Emission ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Infra Red ◽  
Ft Ir

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) powders is synthesized using the mixed powders of CaCO3 refined from oyster shells and phosphoric acid (H3PO4-98%, Daejung) as starting materials. The characteristic evaluation and chemical analysis of the synthesized powders is performed by X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FT-IR), and inductively-coupled plasma atomic emission spectroscopy (ICPAES). XRD analysis of synthetic powder by heat treatment at 1300°C for 2hrs shows only HAp peaks corresponding to stoichiometric HAp. It is confirmed by ICP-AES test that impurities such as Zn, In, Ti, Ba, Cd, Pb, and Mn, is not detected at all, but small amounts of Ti and Be is observed (0.099ppm Ti and 0.002ppm Ba). Variation of bone density is measured by giving medication of HAp powder with drinking water into human body continuously for three month. After the medication, the bone density is higher than the medication before. This means that HAp powder made from this process can be used as improver of bone density.

Effect of Blood Viscosity on Thrombosis Potential Near a Step Wall Transition

2009 ◽  
Author(s):  
Scott C. Corbett ◽  
Amin Ajdari ◽  
Ahmet U. Coskun ◽  
Hamid N.-Hashemi
Keyword(s):  
Blood Flow ◽  
Vessel Wall ◽  
Coagulation Factors ◽  
Artificial Organs ◽  
Physical Factors ◽  
Local Geometry ◽  
Induce Platelet Aggregation ◽  
Shear Rates ◽  
Chemical Factors ◽  
Low Shear

Thrombosis and hemolysis are two problems encountered when processing blood in artificial organs. Physical factors of blood flow alone can influence the interaction of proteins and cells with the vessel wall, induce platelet aggregation and influence coagulation factors responsible for the formation of thrombus, even in the absence of chemical factors in the blood. These physical factors are related to the magnitude of the shear rate/stress, the duration of the applied force and the local geometry. Specifically, high blood shear rates (or stress) lead to damage (hemolysis, platelet activation), while low shear rates lead to stagnation and thrombosis [1].

scholarly journals An Application of Fourier Transform Infra-red (FT-IR) Microspectroscopy to the Study of Cigarette Manufacturing Defects

1992 ◽  
Vol 15 (2) ◽  
pp. 59-64
Author(s):  
MM Thompson ◽  
MS Ireland
Keyword(s):  
Fourier Transform ◽  
Common Type ◽  
Manufacturing Defects ◽  
Infra Red ◽  
Ft Ir ◽  
Ir Microspectroscopy ◽  
Cigarette Manufacturing

AbstractFT-IR microspectroscopy was used to investigate a common type of cigarette defect in which the filter separates from the tobacco rod. Infra-red imagings of the adhesive located at this junction on the tipping papers from both defective and acceptable cigarettes were obtained. A comparison of these data revealed that although adhesive was present in the seam area of the defective cigarettes, the amount of adhesive was significantly less and its distribution was not uniform.

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