scholarly journals Ohmic Heating and Ionization Measurements for an Axial Discharge in Hydrogen

1978 ◽  
Vol 31 (1) ◽  
pp. 61 ◽  
Author(s):  
RC Cross ◽  
BD Blackwell
Keyword(s):  
Theoretical Model ◽  
Energy Loss ◽  
Electron Temperature ◽  
Ohmic Heating ◽  
Hydrogen Gas ◽  
Heating Power ◽  
Experimental Results ◽  
Heating Effect ◽  
Loss Mechanism ◽  
Neutral Particles

Experimental results are presented on the heating effect and rate of ionization produced by an axial discharge (~1O kA) in hydrogen gas at filling pressures of 25--400 mTorr. The electron temperature remains very low (about 1�5 eV) even at ohmic heating power levels as high as 200 MWm-3 ? The results are compared with a theoretical model which assumes that the only energy loss mechanism is ionization of neutral particles. The importance of other loss mechanisms, including convection, conduction and radiation, is also discussed.

scholarly journals The Charge State of Protons with 90 and 100 keV Energies Decelerated in Hydrogen Plasma

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yu Lei ◽  
Rui Cheng ◽  
Yong Tao Zhao ◽  
Xian Ming Zhou ◽  
Yu Yu Wang ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Temperature ◽  
Charge State ◽  
Electron Density ◽  
Effective Charge ◽  
Hydrogen Plasma ◽  
Experimental Results ◽  
Model Calculations ◽  
Plasma Target ◽  
Cold Gas

Energy loss of protons with 90 and 100 keV energies penetrating through a hydrogen plasma target has been measured, where the electron density of the plasma is about 1016 cm−3 and the electron temperature is about 1-2 eV. It is found that the energy loss of protons in the plasma is obviously larger than that in cold gas and the experimental results based on the Bethe model calculations can be demonstrated by the variation of effective charge of protons in the hydrogen plasma. The effective charge remains 1 for 100 keV protons, while the value for 90 keV protons decreases to be about 0.92. Moreover, two empirical formulae are employed to extract the effective charge.

scholarly journals Energy loss of protons in hydrogen plasma

2018 ◽  
Vol 36 (1) ◽  
pp. 98-104 ◽  
Author(s):  
R. Cheng ◽  
X. Zhou ◽  
Y. Wang ◽  
Y. Lei ◽  
Y. Chen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Density ◽  
Potential Application ◽  
Hydrogen Plasma ◽  
Hydrogen Gas ◽  
Experimental Results ◽  
Free Electrons ◽  
Error Limit ◽  
Bound Electrons ◽  
Good Agreement

AbstractThis paper reports the measurement of the energy loss of protons at the energy of 100 keV penetrating a partially ionized hydrogen plasma. The plasma of ne ≈ 1015–16 cm−3; Te ≈ 1–2 eV and lifetime of about 8 µs is created by the hydrogen gas discharge. The experimental results show an increase of a factor of 2.8 in the energy loss, which are in good agreement with the Bethe, Standard Stopping Model, Li–Petrasso and Vlasov models’ predictions within the error limit. The Bethe–Bloch Coulomb logarithm term is found to increase by a factor of 4.0 for free electrons as compared with the situation where bound electrons prevail. The potential application of protons energy loss for diagnosing the electron density in plasma is proposed too.

Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

2020 ◽  
Vol 14 (4) ◽  
pp. 7396-7404
Author(s):  
Abdul Malek Abdul Wahab ◽  
Emiliano Rustighi ◽  
Zainudin A.
Keyword(s):  
Theoretical Model ◽  
Resonance Frequency ◽  
Dynamic Testing ◽  
Experimental Results ◽  
Percentage Error ◽  
Initial Tension ◽  
Average Percentage ◽  
Soft Actuator ◽  
Average Percentage Error ◽  
Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

Experiment analysis of high output pressure piezoelectric pump with straight arm wheeled check valve

2021 ◽  
pp. 1045389X2098700
Author(s):  
Lipeng He ◽  
Xiaoqiang Wu ◽  
Zheng Zhang ◽  
Zhe Wang ◽  
Bangcheng Zhang ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Energy Loss ◽  
Check Valve ◽  
Experimental Results ◽  
Piezoelectric Pump ◽  
Output Pressure ◽  
Pressure Characteristic ◽  
Analysis System ◽  
Experiment Analysis ◽  
High Output

Piezoelectric pumps are applied in many fields, such as chemical analysis system and fluid pumping systems. Piezoelectric pumps with high output pressure can meet the needs of more fields. This article introduces the design and fabrication of a high output pressure piezoelectric pump with straight arm wheeled check valve. In this paper, the influence of straight arm wheeled check valve on the output pressure of piezoelectric pump is deeply discussed from the aspect of energy loss. This study investigated the effect of valve arm number ( N = 2, 3,4, and 5), the valve arm width ( W = 0.8, 1.0, and 1.2 mm), and the valve arm length ( L = 1.92, 2.02, and 2.12 mm) on the output pressure of piezoelectric pump. The output pressure characteristic of straight arm wheeled check valve piezoelectric pump with different valve parameters is obtained by experiment. Experimental results show that when N = 4, W = 1.0 mm, L = 2.02 mm, the output pressure of the straight arm wheeled check valve piezoelectric pump has the best output pressure of 27.41 kPa at 220 V and 85 Hz. This study provides a reference for the further application of piezoelectric pumps in fluid pumping field.

scholarly journals Investigation of thermal conductivity of single-wall carbon nanotubes

2011 ◽  
Vol 15 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Mahmoud Jafari ◽  
Majid Vaezzadeh ◽  
Momhamad Mansouri ◽  
Abazar Hajnorouzi
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Theoretical Model ◽  
Potential Energy ◽  
Experimental Results ◽  
Single Wall Carbon Nanotubes ◽  
Lattice Vibrations ◽  
Single Wall Carbon ◽  
Thermal Potential ◽  
Conductivity Behavior

In this paper, the thermal conductivity of Single-wall carbon nanotubes (SWCNTs) is determined by lattice vibrations (phonons) and free elections. The thermal conductivity of SWCNTs is modeled up to 8-300 K and the observed deviations in K-T figures of SWCNTs are explained in terms of phonon vibrations models. An suitable theoretical model is shown for thermal conductivity behavior with respect to temperature and is generalized for experimental results. This model enables us to calculate thermal conductivity SWNTs and Thermal Potential Energy (TPE).

Theoretical Model for Interfacial Nonlinear Bond Softening Behavior between Embedded Steel and HSHPC

2007 ◽  
Vol 348-349 ◽  
pp. 845-848
Author(s):  
Shan Suo Zheng ◽  
Lei Li ◽  
Guo Zhuan Deng ◽  
Shun Li Che ◽  
Wei Zhao
Keyword(s):  
Theoretical Model ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Nonlinear Process ◽  
Experimental Results ◽  
Interfacial Bond ◽  
Bond Slip ◽  
Softening Behavior ◽  
Bond Softening

The latest experimental study on steel reinforced high strength and high performance concrete (SRHSHPC) specimens shows that there exists interfacial bond softening phenomenon between embedded steel and high strength and high performance concrete (HSHPC), and it makes the shear transfer capacity between shaped steel and HSHPC be progressively reduced. To predict failure load in design, a theoretical model for interfacial bond softening behavior is required. As interfacial bond softening behavior is a nonlinear process involving material properties, it can be analyzed once the relation of interfacial bond stress (τ ) and slippage ( s ) is known. In this paper, the mechanism of interfacial bond-slip is studied, thus a simplified τ − s relation including ascending and descending parts is proposed and employed to analyze the interfacial nonlinear bond-slip process. Based on the interfacial equilibrium between steel and HSHPC as well as the τ − s relation, the basic governing equations in both softened region and elastic region are established and solved for steel strain or stress. At last, the application of the model is verified through comparison with experimental results. The calculating results of the model are found to be in good agreement with experimental results, showing that the model can describe the bond-slip process in real material systems.

ENERGY DEPOSITION OF RELATIVISTIC ELECTRONS IN SUPER-HOT PLASMA

2007 ◽  
Vol 21 (27) ◽  
pp. 1855-1862 ◽  
Author(s):  
TONG-CHENG WU ◽  
XUAN ZHANG ◽  
WEI-KE AN
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Energy Deposition ◽  
Plasma Oscillation ◽  
Lorentz Factor ◽  
Relativistic Electrons ◽  
Exact Relation ◽  
Loss Mechanism ◽  
Electron Collisions ◽  
Thermonuclear Fuel

The intense ultrashort laser interacting with the thermonuclear fuel may produce a relativistic plasma and MeV electron beam, how to fix the Lorentz factors of the particles in the plasma and model the energy deposition of MeV electron beams are important subjects. In this letter, we demonstrate the exact relation between the average Lorentz factor and the temperature of the system; and then obtained the relativistic modified formula for the energy loss of the relativistic electron-beam due to binary electron-electron collisions. Another important energy loss mechanism, the excitation of Langmuir collective plasma oscillation, is also treated within the relativistic framework. Hence, we re-examine theoretically the possibility of igniting hot spots in the super-compressed DT target and the answer is that the fast ignitor scenario is able to yield thermonuclear ignition in the target.

Initial Experiments on the Control of a Mobile Tower Crane

2007 ◽  
Author(s):  
Joshua Vaughan ◽  
William Singhose ◽  
Paulo Debenest ◽  
Edwardo Fukushima ◽  
Shigeo Hirose
Keyword(s):  
Theoretical Model ◽  
Material Handling ◽  
Operational Efficiency ◽  
Experimental Results ◽  
Input Shaping ◽  
Oscillatory Dynamics ◽  
Tower Crane ◽  
Operational Capabilities ◽  
The World

Cranes are used extensively throughout the world in a wide variety of construction and material handling applications. The speed at which these cranes are operated is limited by payload oscillation. Input shaping is one method that reduces this oscillation, allowing higher speeds and improving operational efficiency. Another method to improve the operational capabilities of cranes is to allow base motion. This paper presents initial experimental results from a portable, mobile tower crane. A theoretical model of the crane is presented and experimentally verified. The oscillatory dynamics of the crane are highlighted and controllers to combat these unwanted dynamics are presented.

Physics-Based Friction Model With Potential Application in Numerical Models for Tire-Road Traction

2017 ◽  
Author(s):  
Anahita Emami ◽  
Seyedmeysam Khaleghian ◽  
Chuang Su ◽  
Saied Taheri
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Numerical Models ◽  
Surface Profile ◽  
Viscoelastic Behavior ◽  
Numerical Results ◽  
Experimental Results ◽  
Real Contact Area ◽  
Computer Algorithms ◽  
Road Surfaces

Good understanding of friction in tire-road interaction is of critical importance for vehicle dynamic control systems. Most of the friction models proposed to describe the friction coefficient between tire-treads and road surfaces have been developed based on empirical or semi-empirical relations that are not able to include many effective parameters involved in the tire-road interactions. Therefore, these models are just useful in limited conditions similar to the experiments, and do not accurately represent tire-road traction in numerical tire models. However, in last two decades, a few theoretical models have been developed to calculate the tire-road friction coefficient theoretically by considering both viscoelastic behavior of tire tread compounds and multi-scale interactions between tire treads and rough road surfaces. In this article, a novel physics-based model proposed by Persson has been investigated and used to develop computer algorithms for calculation of sliding friction coefficient between a tire tread compound and a rough substrate. The viscoelastic behavior of tread compound and the surface profile of rough counter surface are the inputs of this physics-based theoretical model. The numerical results of the model have been compared with the experimental results obtained from a dynamic friction tester designed and built in the Center for Tire Research (CenTire). Good agreement between numerical results of theoretical model and experimental results has been found at intermediate range of slip velocities considering the effect of adhesion and shearing in the real contact area in addition to hysteresis friction due to internal energy dissipation in the tire tread compound.

Sign in / Sign up

Export Citation Format

Share Document