scholarly journals Application of Oobleck as a Speed Breaker

2020 ◽  
Vol 8 (6) ◽  
pp. 884-886
Keyword(s):  
Thermal Conductivity ◽  
Shear Stress ◽  
Newtonian Fluid ◽  
Corn Starch ◽  
Chemical Reactivity ◽  
Packaging Material ◽  
Packing Material ◽  
Kevlar Fiber ◽  
Water Proofing ◽  
Boiled Water

A fluid in which the shear stress is directly proportional to strain, then it is termed as a Newtonian law of viscosity. If a fluid which does not obeys this law, then it is named as a Non -Newtonian fluid and Oobleck is one of the non -Newtonian fluid i.e.., (shear stress is indirectly proportional to the velocity gradient) and Oobleck is made by mixing the corn starch and boiled water in the appropriate ratio of 1:1.25 to get the non -Newtonian fluid property. Then, the mixture made is stored in water proofing packaging material i.e., Kevlar fiber and it is used as replacement of existing conventional speed breaker. The aim of this project is to apply the Oobleck mixture for a speed breaker, study about it’s characteristics and compare it with Conventional as well as plastic speed breaker. It plays a major role in controlling the speed of the vehicle and helps in preventing the accidents. The Oobleck is stored as a packing material in Kevlar fiber which retains the properties of the inner material forever and is having low thermal conductivity and chemical reactivity. The result indicates that the usage of Oobleck in speed breaker is sensitive to the speed of the vehicles and cost of manufacturing Oobleck speed breaker is comparatively lower than the conventional speed breaker.

scholarly journals Preparation and characterization of corn starch/PVA/glycerol composite films incorporated with ε-polylysine as a novel antimicrobial packaging material

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Gao Yurong ◽  
Li Dapeng
Keyword(s):  
Water Solubility ◽  
Corn Starch ◽  
Composite Films ◽  
Antimicrobial Properties ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Packaging Material ◽  
Hydroxyl Group ◽  
Electron Microscopic ◽  
Antimicrobial Packaging

AbstractCorn starch/polyvinyl alcohol (PVA)/glycerol composite films incorporated with ε-polylysine were prepared, and their properties were investigated. The Fourier-transform infrared (FTIR) spectroscopy indicated that the interactions happened between the amino group of ε-polylysine and hydroxyl group starch/PVA composite films. X-ray diffraction (XRD) analysis showed that the addition of ε-polylysine decreased the intensity of all crystal peaks. Thermogravimetric (TGA) analysis suggested that ε-polylysine improved the thermal stability of composite films. Scanning electron microscopic (SEM) analysis showed that the upper surface of composite films incorporated with ε-polylysine presented more compact and flat surface. The antimicrobial activity of the composite film progressively increased with the increasing of ε-polylysine concentration (P < 0.05). The tensile strength, elongation at break and water absorption significantly increased, whereas water solubility decreased with the increasing of ε-polylysine concentration (P < 0.05). Therefore, the corn starch/PVA/glycerol composite films incorporated with ε-polylysine had good mechanical, physical and antimicrobial properties and could have potential application as a novel antimicrobial packaging material.

Solid Micro-Beads Hetero-Structure Fuel for Ultra-high Temperature Applications

2006 ◽  
Vol 981 ◽  
Author(s):  
Liviu Popa-Simil ◽  
Gabriel Vasilescu
Keyword(s):  
Thermal Conductivity ◽  
Gas Turbines ◽  
Nuclear Reactor ◽  
Chemical Reactivity ◽  
Fission Products ◽  
Total Radioactivity ◽  
Low Flow ◽  
Hetero Structure ◽  
Continuous Release ◽  
Operation Temperature

AbstractHigher conversion efficiencies require high operation temperatures that are difficult to obtain due to the actual thermo-physical properties of the nuclear fuels. The initial intrinsic thermal conductivity of the actual fuel pellets, mainly ceramics like structures (oxides, nitrides, carbides, MOX, beads) is low. The center of the pellet is near melting temperature while the cladding operation temperature has to be low. The fission products deposition and burnup effects are further dimming the thermal conductivity. More the cooling agent's chemical reactivity increases with temperature is another main reasons of keeping the operation temperature low. The usage of a hetero-structure of solid fuel soaked into a drain fluid is increasing the thermal conductivity. Properly shaped beads structure drives to the possibility of preventing most of the fission products of being stored inside the fuel lattice deteriorating its properties, being drained outside the nuclear reactor. This changes inspired from the nature, makes the nuclear reactor resembling with a plant having self cleaning and curing properties while operating at higher temperatures. Immersing the fuel into liquid metal higher operation temperatures are allowed due to increase in thermal conductivity by 3 to 20 times. Making the fuel beads shorter than the range of fission products, their trajectories end in the drain liquid that is tolerant to nuclear recoils damage. Due to better thermal conductivity the temperature field differences inside the nuclear reactor becomes smaller, allowing the operating temperature to rise significantly without safety concerns. There is possible to continuously remove the fission products by smoothly circulating the drain liquid. The low flow is needed to give time to short lives fission products to decay inside the reactor highly shielded volume. There are several fissionable materials and drain liquids matching which assure high operation temperatures, and allow He cooling, and high temperatures gas turbines cycles. The conversion efficiency might be higher than 70% depending on the chosen actinide / drain-liquid / cooling-liquid combination. The new concept on fission products continuous release and separation minimizes the waste and the total radioactivity stored inside the reactor to few weeks integrated operation amount remaining constant over the time. That makes the fuel's remnant radioactivity lower by a factor >100 than the actual reactors level. The fuel reactivity might be controlled by poisoning and transmutation or by assuring specific reactive geometries which to allow a ultrahigh burnup without the need of over-criticality loads. The fuel's deformability opens the way for interesting applications. The advantages of micro structured nuclear fuel are higher thermal conductivity, fission products removal, appropriate reactivity, higher efficiencies and longer fuel life.

Accurate Prediction of Wall Shear Stress in a Stented Artery: Newtonian Versus Non-Newtonian Models

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Juan Mejia ◽  
Rosaire Mongrain ◽  
Olivier F. Bertrand
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Linear Model ◽  
Newtonian Fluid ◽  
Nonlinear Model ◽  
Numerical Models ◽  
Neointimal Hyperplasia ◽  
Computational Cost ◽  
Arterial Segment ◽  
Wall Shear

A significant amount of evidence linking wall shear stress to neointimal hyperplasia has been reported in the literature. As a result, numerical and experimental models have been created to study the influence of stent design on wall shear stress. Traditionally, blood has been assumed to behave as a Newtonian fluid, but recently that assumption has been challenged. The use of a linear model; however, can reduce computational cost, and allow the use of Newtonian fluids (e.g., glycerine and water) instead of a blood analog fluid in an experimental setup. Therefore, it is of interest whether a linear model can be used to accurately predict the wall shear stress caused by a non-Newtonian fluid such as blood within a stented arterial segment. The present work compares the resulting wall shear stress obtained using two linear and one nonlinear model under the same flow waveform. All numerical models are fully three-dimensional, transient, and incorporate a realistic stent geometry. It is shown that traditional linear models (based on blood’s lowest viscosity limit, 3.5 Pa s) underestimate the wall shear stress within a stented arterial segment, which can lead to an overestimation of the risk of restenosis. The second linear model, which uses a characteristic viscosity (based on an average strain rate, 4.7 Pa s), results in higher wall shear stress levels, but which are still substantially below those of the nonlinear model. It is therefore shown that nonlinear models result in more accurate predictions of wall shear stress within a stented arterial segment.

Exact Solutions for the Flow of Fractional Maxwell Fluid in Pipe-Like Domains

2016 ◽  
Vol 8 (5) ◽  
pp. 784-794 ◽  
Author(s):  
Vatsala Mathur ◽  
Kavita Khandelwal
Keyword(s):  
Shear Stress ◽  
Velocity Field ◽  
Newtonian Fluid ◽  
Outer Cylinder ◽  
Fluid Motion ◽  
Maxwell Fluid ◽  
Circular Cylinders ◽  
Generalized Solutions ◽  
Special Cases ◽  
Graphical Illustration

AbstractThis paper presents an analysis of unsteady flow of incompressible fractional Maxwell fluid filled in the annular region between two infinite coaxial circular cylinders. The fluid motion is created by the inner cylinder that applies a longitudinal time-dependent shear stress and the outer cylinder that is moving at a constant velocity. The velocity field and shear stress are determined using the Laplace and finite Hankel transforms. Obtained solutions are presented in terms of the generalized G and R functions. We also obtain the solutions for ordinary Maxwell fluid and Newtonian fluid as special cases of generalized solutions. The influence of different parameters on the velocity field and shear stress are also presented using graphical illustration. Finally, a comparison is drawn between motions of fractional Maxwell fluid, ordinary Maxwell fluid and Newtonian fluid.

scholarly journals Modeling Blood Pulsatile Turbulent Flow in Stenotic Coronary Arteries

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Flow ◽  
Newtonian Fluid ◽  
Coronary Arteries ◽  
Pathological Condition ◽  
Flow Behavior ◽  
Wall Shear ◽  
Stenotic Arteries

Atherosclerosis is a potentially serious illness where arteries become clogged with fatty substances called plaques. Over the years, this pathological condition has been deeply studied and computational fluid dynamics has played an important role in investigating the blood flow behavior. Commonly, the blood flow is assumed to be laminar and a Newtonian fluid. However, under a stenotic condition, the blood behaves as a non-Newtonian fluid and the pulsatile blood flow through coronary arteries could result in a transition from laminar to turbulent flow condition. The present study aims to analyze and compare numerically the blood flow behavior, applying the k-ω SST model and a laminar assumption. The effects of Newtonian and non-Newtonian (Carreau) models were also studied. In addition, the effect of the stenosis degree on velocity fields and wall shear stress based descriptors were evaluated. According to the results, the turbulent model is shown to give a better overall representation of pulsatile flow in stenotic arteries. Regarding, the effect of non-Newtonian modeling, it was found to be more significant in wall shear stress measurements than in velocity profiles. In addition, the appearance of recirculation zones in the 50% stenotic model was observed during systole, and a low TAWSS and high OSI were detected downstream of the stenosis which, in turn, are risk factors for plaque formation. Finally, the turbulence intensity measurements allowed to distinguish regions of recirculating and disturbed flow.

scholarly journals Sustainable Bioactive Packaging Based on Thermoplastic Starch and Microalgae

2021 ◽  
Vol 23 (1) ◽  
pp. 178
Author(s):  
Anna Martina Tedeschi ◽  
Fabrizio Di Caprio ◽  
Antonella Piozzi ◽  
Francesca Pagnanelli ◽  
Iolanda Francolini
Keyword(s):  
Corn Starch ◽  
Transmission Rate ◽  
Thermoplastic Starch ◽  
Packaging Material ◽  
Water Vapor Transmission Rate ◽  
Mechanical Stiffness ◽  
Plastic Packaging ◽  
Flexible Packaging ◽  
Starch Films ◽  
Tetradesmus Obliquus

This study combines the use of corn starch and Tetradesmus obliquus microalgae for the production of antioxidant starch films as flexible packaging material. Starch was plasticized with glycerol and blended with 1 w% polyallylamine chosen as an agent to modify the film physical properties. The addition of polyallylamine improved film water stability and water vapor transmission rate as well as mechanical stiffness and tenacity. The dried Tetradesmus obliquus microalgae, which showed an EC50 value of 2.8 mg/mg DPPH (2.2-Diphenyl-1-picrylhydrazyl radical), was then used as antioxidant filler. The addition of microalgae provided the films with good antioxidant activity, which increased with microalgae content increasing. To our knowledge, this is the first study reporting the development of sustainable bioactive packaging films composed of almost 100% starch, and follows the European union’s goals on plastics strategy concerning the promotion of bio-based, compostable plastics and the setting up of approaches to prevent food waste with a simple plastic packaging.

scholarly journals The Effect of Different Plant Oil Impregnation and Hardening Temperatures on Physical-Mechanical Properties of Modified Biocomposite Boards Made of Hemp Shives and Corn Starch

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5275
Author(s):  
Dovilė Vasiliauskienė ◽  
Giedrius Balčiūnas ◽  
Renata Boris ◽  
Agnė Kairytė ◽  
Arūnas Kremensas ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Corn Starch ◽  
Protective Coatings ◽  
Relative Deformation ◽  
Tung Tree ◽  
Plant Oil ◽  
Performance Enhancing

In this study, tung tree and linseed drying oils, as well as semi-drying hempseed oil, were analyzed as the protective coatings for biocomposite boards (BcB) made of hemp shives, corn starch binder, and the performance-enhancing additives. The hydrophobization coatings were formed at 40, 90, and 120 °C temperatures, respectively. The physical-mechanical properties such as the compressive strength, thermal conductivity, dimensional stability, water absorption, and swelling were tested. In addition, scanning electron microscopy (SEM) was employed for the analysis of the board microstructure to visualize the oil fills and impregnation in pores and voids. It was demonstrated that the compressive strength of oil-modified BcBs compared to uncoated BcBs (at 10% of relative deformation) increased by up to 4.5-fold and could reach up to 14 MPa, water absorption decreased up to 4-fold (from 1.34 to 0.37 kg/m2), swelling decreased up to 48% (from 8.20% to 4.26%), whereas the thermal conductivity remained unchanged with the thermal conductivity coefficient of around 0.085 W/m·K. Significant performance-enhancing properties were obtained due to the formation of a protective oil film when the tung tree oil was used.

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