Deformation of a Moving Micro-Droplet

2019 ◽  
Author(s):  
Yonghong Zhong ◽  
Qichun Nie ◽  
Zhongyi Liu ◽  
Haisheng Fang
Keyword(s):  
Driving Force ◽  
Transition Point ◽  
Unstable State ◽  
Control Methods ◽  
Single Droplet ◽  
Maximum Deformation ◽  
Deformation Curves ◽  
Peak Point ◽  
Primary Droplet ◽  
Minimum Deformation

Abstract Inkjet technology being an essential tool features high resolution and wide applicability. The generation of stable droplets is of great significance in many applications including 3D printing, solar cells and drug delivery. A stable ejected droplet can be a single droplet without satellite droplets (Situation 1), or a single primary droplet with a satellite that merges into the primary later (Situation 2). The deformation process of a stable droplet is directly related to accuracy and efficiency of the droplet delivery. In this paper, we adopt computational fluid dynamics to investigate deformation of a moving stable micro-droplet. It is found that as the driving force rises, the ejected droplets change from Situation 1 to Situation 2, and then to the unstable state after the driving force exceeds a critical value. In the meantime, the maximum deformation of the droplet firstly increases, and then decreases followed by a further increase. The minimum deformation undergoes a converse transition. It further reveals that two essential points of the maximum deformation curves, the peak point (within Situation 1) and the transition point (from Situation 1 to Situation 2), are correlated with ratio of the droplet velocity to the Capillary velocity. The peak point has a ratio between 2.7 and 3.1, and the transition point locates where the ratio plus a constant equals 3.4. New control methods have proposed based on the locations of the maximum deformation extent.

scholarly journals Accuracy analysis and optimization of infrared guidance test device

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092265
Author(s):  
Zhou Wang ◽  
Yin Chen ◽  
Tao Wang ◽  
Bo Zhang
Keyword(s):  
Physical Simulation ◽  
Orthogonal Experiment ◽  
Target Position ◽  
Design Parameters ◽  
Test Device ◽  
Factors Affecting ◽  
Pointing Error ◽  
Maximum Deformation ◽  
Minimum Deformation ◽  
Shell Optimization

As an important modern weapon, the development of infrared-guided missile reflects comprehensive national strength of a country. Therefore, it is especially important to establish a semi-physical simulation device to test the performance of missile, and the test device requires high accuracy. Based on the above background, an infrared guidance test device is designed in this article. The accuracy of its shell and rotating mechanism are studied in detail, and the error factors are quantified to provide theoretical basis for structural optimization. The orthogonal experiment design reduces the number of sensitivity analysis experiments on key design parameters. Factors affecting the maximum deformation and overall quality of the shell were determined. The range method was used to analyze sensitivity factors, and the final optimization result that met the minimum deformation and minimum quality was determined. Experimental results show that the rotation error of the main shaft of the rotating mechanism includes axial, radial, and angular motion errors, and experimental value is basically consistent with theoretical value. After the shell optimization, the infrared target pointing error [Formula: see text] and the infrared target position offset error ξ′ = 0.1525 mm meet the accuracy requirements. This method can provide new ideas for precision research and optimization of structural design of rotating mechanism.

Effect of Electrical Pulsing on Various Heat Treatments of 5XXX Series Aluminum Alloys

2008 ◽  
Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Timothy A. McNeal ◽  
John T. Roth ◽  
Sung-Tae Hong ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Superplastic Deformation ◽  
Deformation Process ◽  
Electrical Current ◽  
Heat Treatments ◽  
Maximum Deformation ◽  
Aluminum Specimen ◽  
Electrical Pulses ◽  
Minimum Deformation ◽  
Diffuse Neck

Previous studies have shown that the presence of a pulsed electrical current, applied during the deformation process of an aluminum specimen, can significantly improve the formability of the aluminum without heating the metal above its maximum operating temperature range. The research herein extends these findings by examining the effect of electrical pulsing on 5052 and 5083 Aluminum Alloys. Two different parameter sets were used while pulsing three different heat treatments (As Is, 398°C, and 510°C) for each of the two aluminum alloys. For this research, the electrical pulsing is applied to the aluminum while the specimens are deformed, without halting the deformation process. The analysis focuses on establishing the effect the electrical pulsing has on the aluminum alloy’s various heat treatments by examining the displacement of the material throughout the testing region of dogbone shaped specimens. The results from this research show that pulsing significantly increases the maximum achievable elongation of the aluminum (when compared to baseline tests conducted without electrical pulsing). Significantly reducing the engineering flow stress within the material is another beneficial effect produced by electric pulsing. The electrical pulses also cause the aluminum to deform non-uniformly, such that the material exhibits a diffuse neck where the minimum deformation occurs near the ends of the specimen (near the clamps) and the maximum deformation occurs near the center of the specimen (where fracture ultimately occurs). This diffuse necking effect is similar to what can be experienced during superplastic deformation. However, when comparing the presence of a diffuse neck in this research, electrical pulsing does not create as significant of a diffuse neck as superplastic deformation. Electrical pulsing has the potential to be more efficient than traditional methods of incremental forming since the deformation process is never interrupted. Overall, with the greater elongation and lower stress, the aluminum can be deformed quicker, easier, and to a greater extent than is currently possible.

Control and Optimizing of Unstable State in Continuous Casting Process with Automatic System

2012 ◽  
Vol 472-475 ◽  
pp. 3057-3062
Author(s):  
Zhi Zheng Yang ◽  
Yan Feng Wang ◽  
Jiang Ping Rao ◽  
Zhu Gang Peng
Keyword(s):  
Continuous Casting ◽  
New Technology ◽  
Casting Process ◽  
Unstable State ◽  
Control Methods ◽  
Unsteady State ◽  
Level Control ◽  
Continuous Casting Process ◽  
Controlling System ◽  
And Control

Features and control methods in processes of unstable continuous casting of the 4th department of general steelmaking factory of WISCO were introduced, including ladle free-opening, tundish auto-casting, liquid level control and submerged nozzle’s quick replacing of mould, slag detection of ladle and so on. Countermeasures including updating facilities, improving accurate of controlling system, developing new technology were proved to be effective in practice, they can minimize the bad effect of the unsteady state to the producing stability and slab quality.

Formability of Al 5xxx Sheet Metals Using Pulsed Current for Various Heat Treatments

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Timothy A. McNeal ◽  
John T. Roth ◽  
Sung-Tae Hong ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Superplastic Deformation ◽  
Deformation Process ◽  
Electrical Current ◽  
Heat Treatments ◽  
Maximum Deformation ◽  
Aluminum Specimen ◽  
Electrical Pulses ◽  
Minimum Deformation ◽  
Diffuse Neck

Previous studies have shown that the presence of a pulsed electrical current, applied during the deformation process of an aluminum specimen, can significantly improve the formability of the aluminum without heating the metal above its maximum operating temperature range. The research herein extends these findings by examining the effect of electrical pulsing on 5052 and 5083 aluminum alloys. Two different parameter sets were used while pulsing three different heat-treatments (as-is, 398°C, and 510°C) for each of the two aluminum alloys. For this research, the electrical pulsing is applied to the aluminum while the specimens are deformed without halting the deformation process (a manufacturing technique known as electrically assisted manufacturing). The analysis focuses on establishing the effect of the electrical pulsing has on the aluminum alloy’s various heat-treatments by examining the displacement of the material throughout the testing region of dogbone-shaped specimens. The results from this research show that pulsing significantly increases the maximum achievable elongation of the aluminum (when compared with baseline tests conducted without electrical pulsing). Another beneficial effect produced by electrical pulsing is that the engineering flow stress within the material is considerably reduced. The electrical pulses also cause the aluminum to deform nonuniformly, such that the material exhibits a diffuse neck where the minimum deformation occurs near the ends of the specimen (near the clamps) and the maximum deformation occurs near the center of the specimen (where fracture ultimately occurs). This diffuse necking effect is similar to what can be experienced during superplastic deformation. However, when comparing the presence of a diffuse neck in this research, electrical pulsing does not create as significant of a diffuse neck as superplastic deformation. Electrical pulsing has the potential to be more efficient than the traditional methods of incremental forming since the deformation process is never interrupted. Overall, with the greater elongation and lower stress, the aluminum can be deformed quicker, easier, and to a greater extent than is currently possible.

Fatigue crack growth modelling by successive blocking of dislocations

1992 ◽  
Vol 437 (1900) ◽  
pp. 375-390 ◽  
Keyword(s):  
Plastic Zone ◽  
Crack Growth ◽  
Driving Force ◽  
Transition Point ◽  
Growth Modelling ◽  
Microstructural Parameter ◽  
Critical Position ◽  
Crack Driving Force ◽  
Short Cracks ◽  
The Moment

Work hardening and the study of instability is incorporated into the description of the growth of a crack in terms of the successive blocking of the plastic zone by slip barriers, such as grain boundaries, and the subsequent initiation of the slip in neighbouring grains. A simple equation is derived to determine the critical position of the crack tip in relation to the grain boundary where the plastic zone is blocked at the moment of slip transmission. The intermittent pattern of decelerating and accelerating behaviour of short cracks and the existence of non-propagating cracks is explained. Instability in crack growth is seen to occur when the rate of hardening is insufficient to compensate for the increase in crack driving force in relation to the increase in crack length. This is associated with fracture toughness. The transition point between the short and long crack régimes is seen to occur when the size of the plastic zone is of the order of the microstructural parameter.

Small Angle X-Ray Scattering Studies of Fatigue in Polystyrene

1986 ◽  
Vol 79 ◽  
Author(s):  
H. R. Brown ◽  
E. J. Kramer ◽  
R. A. Bubeck
Keyword(s):  
Small Angle ◽  
Single Cycle ◽  
Fatigue Lifetime ◽  
Maximum Deformation ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Minimum Deformation ◽  
Small Deformations ◽  
Fibril Diameter

AbstractSmall angle scattering has been used to study the mechanical fatigue of crazes in polystyrene. The high radiation intensity obtainable from a synchrotron has permitted the examination of the processes that occur during the fatigue in real time. Both the short term changes that occur within a single cycle and the long term changes that occur over many cycles have been observed.Most of the craze growth, as measured by the scattering invariant obtained at peak deformation, occurred in the first cycle of fatigue. However the craze fibril diameter, obtained by Porod analysis, doubled over 250 cycles. As the volume of craze was not growing during during the fatigue this fibril diameter increase was believed to occur by change, that is coalescence, of the preexisting fibrils.The SAXS patterns obtained at a number of different deformations within a single cycle were compared with calculated patterns obtained assuming that the fibrils bend in a sinusoidal manner. Good qualitative agreement was obtained so it was concluded that the craze fibrils showed considerable deformation as the craze was unloaded and then straightened out again on reloading. When the ratio of minimum to maximum deformation was decreased from 0.9 to 0.5 the fibril deformation (contraction) increased to 10% with the fibrils remaining straight. As the minimum deformation was decreased below this the craze stress tends to zero and fibril buckling was evident. The main changes in fatigue lifetime occurred over the regions where there fibrils were straight, perhaps because buckling involves relatively small deformations.

scholarly journals Влияние легирующих добавок кобальта и молибдена на структуру и параметры памяти формы пористого реакционно-спеченного никелида титана

2018 ◽  
Vol 44 (14) ◽  
pp. 103
Author(s):  
Н.В. Артюхова ◽  
Ю.Ф. Ясенчук ◽  
А.С. Гарин ◽  
В.Э. Гюнтер
Keyword(s):  
Nickel Titanium ◽  
Reaction Sintering ◽  
Structure And Properties ◽  
Porous Nickel ◽  
Maximum Deformation ◽  
Initial Stage ◽  
Ni Powder ◽  
Accumulated Strain ◽  
Minimum Deformation ◽  
Tini Phase

AbstractWe have studied the structure and properties of porous nickel titanium (TiNi) alloys obtained upon reaction sintering of Ti and Ni powders with Co and Mo additives. It is established that Co and Mo doping additives retain the compaction of Ni powder achieved at the initial stage of sintering. The maximum deformation of porous samples loaded in the austenite state was observed upon adding Co, while the addition of Mo resulted in minimum deformation. The addition of Co leads to single-stage martensitic transformation in TiNi phase, while the addition of Mo leads to the two-stage transformation that is more homogeneous over the volume. Both Co and Mo additives lead to increase in the maximum accumulated strain due to the formation of favorably oriented stress-induced martensite and reoriented quench-induced martensite.

scholarly journals Quantifying Heterogeneity According to Deformation of the U937 Monocytes and U937-Differentiated Macrophages Using 3D Carbon Dielectrophoresis in Microfluidics

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 576 ◽  
Author(s):  
Meltem Elitas ◽  
Esra Sengul
Keyword(s):  
Fluid Shear Stress ◽  
Cell Damage ◽  
Electrode Array ◽  
Crossover Frequency ◽  
Label Free ◽  
Electromechanical Properties ◽  
Maximum Deformation ◽  
Deformation Index ◽  
Minimum Deformation ◽  
Downstream Analysis

A variety of force fields have thus far been demonstrated to investigate electromechanical properties of cells in a microfluidic platform which, however, are mostly based on fluid shear stress and may potentially cause irreversible cell damage. This work presents dielectric movement and deformation measurements of U937 monocytes and U937-differentiated macrophages in a low conductive medium inside a 3D carbon electrode array. Here, monocytes exhibited a crossover frequency around 150 kHz and presented maximum deformation index at 400 kHz and minimum deformation index at 1 MHz frequencies at 20 Vpeak-peak. Although macrophages were differentiated from monocytes, their crossover frequency was lower than 50 kHz at 10 Vpeak-peak. The change of the deformation index for macrophages was more constant and lower than the monocyte cells. Both dielectric mobility and deformation spectra revealed significant differences between the dielectric responses of U937 monocytes and U937-differentiated macrophages, which share the same origin. This method can be used for label-free, specific, and sensitive single-cell characterization. Besides, damage of the cells by aggressive shear forces can, hence, be eliminated and cells can be used for downstream analysis. Our results showed that dielectric mobility and deformation have a great potential as an electromechanical biomarker to reliably characterize and distinguish differentiated cell populations from their progenitors.

scholarly journals Thermodynamic phase transition and global stability of the regular Hayward black hole surrounded by quintessence

2020 ◽  
Vol 35 (16) ◽  
pp. 2050129
Author(s):  
Kamiko Kouemeni Jean Rodrigue ◽  
Mahamat Saleh ◽  
Bouetou Bouetou Thomas ◽  
Kofane Timoleon Crepin
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Transition Point ◽  
Second Order ◽  
Hawking Temperature ◽  
Unstable State ◽  
Second Phase ◽  
Normalization Factor ◽  
First Order ◽  
Transition Points

In this work, we investigate the thermodynamic and the stability of the regular Hayward black hole surrounded by quintessence. Using the metric of the black hole surrounded by quintessence and the new approach of the holographic principle, we derive the expression of the Unruh–Verlinde temperature. Hawking temperature and specific heat are derived using the first law of black holes thermodynamics. Gibbs free energy is also evaluated. The behaviors of these quantities show that, the parameter of the regular Hayward black hole [Formula: see text] induces a decreasing of the Hawking temperature of the black hole, and that decrease is accentuated when increasing the magnitude of [Formula: see text] and the normalization factor related to the density of quintessence. For the lower entropies, the black hole passes from the unstable phase to the stable one by a first-order thermodynamics phase transition. When increasing the entropy, a second phase transition occurs. This new phase transition is a second-order thermodynamics phase transition and brings the black hole to unstable state. It results that, when increasing of magnitude of [Formula: see text], the phase transition points are shifted to the higher entropies. Moreover, the phenomena of phase transitions are preserved by adding the quintessence. Furthermore, when increasing the normalization factor of quintessence, the first-order transition point is shifted to higher entropies, while the second-order thermodynamics phase transition point is shifted to lower entropies.

scholarly journals The types of mechanical and thermal stresses on the first stage rotor blade of a turbine

2019 ◽  
Vol 7 (1) ◽  
pp. 1-11
Author(s):  
Rafid M. Hannun ◽  
Hazim I. Radhi ◽  
Noura A. Essi
Keyword(s):  
Power Plant ◽  
Rotor Blade ◽  
Thermal Stresses ◽  
Leading Edge ◽  
Steam Pressure ◽  
Mechanical Stresses ◽  
Trailing Edge ◽  
Operational Conditions ◽  
Maximum Deformation ◽  
Minimum Deformation

Introduction: In this paper, the simulation of first stage of low pressure turbine for Nasiriya Power Plant was done to study the aerodynamic characteristic of steam along stage at load 70 MW, also the two types of mechanical stresses on the first stage rotor blade were studied in this paper. Materials and Methods:The material of blade was X20Cr13 stainless steel grade 1.4021. The first type of mechanical stresses which due to the steam pressure on the blade was analyzed. The seconds types of mechanical stresses that the centrifugal stresses on the blade. The AutoCAD software code was used for modeling the turbine stage, the dimensions and operational conditions were obtained practically from Nasiriya power plant and ANSYS (15.0) software was used to make simulate the turbine. Results and Discussion: The results showed that maximum steam velocity occurred at trailing edge of stationary blades and leading edge of rotating blades, also the maximum stresses occurred at the leading edge and trailing edge of root blade, the stresses due to the effect of centrifugal force is larger than the stresses due the pressure force. Conclusions: The maximum deformation occurred at tip of blade and minimum deformation depicted at root of blade.

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