Thermal Gradients Govern Impact Dynamics in Thermoplastic Polymer Cold Spray

2021 ◽  
Author(s):  
Tristan W. Bacha ◽  
Nand K. Singh ◽  
Isaac M. Nault ◽  
Behrad Koohbor ◽  
Francis M. Haas ◽  
...  
Keyword(s):  
Cold Spray ◽  
Impact Dynamics ◽  
Thermal Gradients ◽  
Thermoplastic Polymer

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

Magnetostrictive Cold Spray Sensor for Long-Term or Harsh Environment Ultrasound

2019 ◽  
Author(s):  
S. W. Glass ◽  
◽  
J. P. Lareau ◽  
K. S. Ross ◽  
S. Ali ◽  
...  
Keyword(s):  
Cold Spray ◽  
Harsh Environment

ISOPLAST 101 UNREINFORCED

Alloy Digest ◽  
1989 ◽  
Vol 38 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Impact Strength ◽  
High Impact ◽  
Thermoplastic Polymer ◽  
Moisture Sensitivity ◽  
Chemical Company ◽  
High Impact Strength ◽  
Rigid Amorphous ◽  
Excellent Chemical

Abstract ISOPLAST 101, unreinforced, is a rigid, amorphous polyurethane thermoplastic polymer. It is opaque and impact modified. It is injection moldable and extrudable. It is characterized by its high impact strength, high abrasion resistance, excellent chemical and solvent resistance and low moisture sensitivity. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on wear resistance. Filing Code: P-10. Producer or source: The Dow Chemical Company.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

Toward living nanomachines

2018 ◽  
Author(s):  
Christof Mast ◽  
Friederike Möller ◽  
Moritz Kreysing ◽  
Severin Schink ◽  
Benedikt Obermayer ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Thermal Gradient ◽  
Molecular Level ◽  
Minimal System ◽  
Thermal Gradients ◽  
Temperature Oscillations ◽  
Fluid Convection ◽  
Inanimate Matter ◽  
High Concentrations ◽  
Periodic Temperature

How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

scholarly journals 2.45 GHz Patch Antenna Based on Thermoplastic Polymer Substrates

2018 ◽  
Author(s):  
Nurul Hanani Manab ◽  
Elfarizanis Baharudin ◽  
Fauziahanim Che Seman ◽  
Alyani Ismail
Keyword(s):  
Patch Antenna ◽  
Thermoplastic Polymer ◽  
Polymer Substrates

Cold Spray Construction of Nanostructured Titania Coatings for Photocatalytic Applications

2021 ◽  
Author(s):  
Jin Liu ◽  
Yi Liu ◽  
Xinkun Suo ◽  
Leszek Latka ◽  
Aleksandra Małachowski ◽  
...  
Keyword(s):  
Cold Spray ◽  
Titania Coatings ◽  
Photocatalytic Applications ◽  
Nanostructured Titania

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

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