Sticking Phenomena Research Articles

Quantum correlations for a simple kicked system with mixed phase space.

We investigate both the classical and quantum dynamics for a simple kicked system (the standard map) that classically has mixed phase space. For initial conditions in a portion of the chaotic region that is close enough to the regular region, the phenomenon of sticking leads to a power-law decay with time of the classical correlation function of a simple observable. Quantum mechanically, we find the same behavior, but with a smaller exponent. We consider various possible explanations of this phenomenon, and settle on a modification of the Meiss-Ott Markov tree model that takes into account quantum limitations on the flux through a turnstile between regions corresponding to states on the tree. Further work is needed to better understand the quantum behavior.

P‐144: A Systematic Research of Image Sticking in Fringe Field Switching Liquid Crystal Displays

A systematic research of image sticking (IS) in a fringe field switching liquid crystal displays is demonstrated. After the IS test of mosaic pattern and switching to the mid‐grey level image, the root mean square voltage (Vrms) difference between the black and white block should be controlled under the 1 mV to avoid the phenomenon of image sticking detected by the human eye. A detailed analysis of voltage calculation and how to decrease the difference of Vrms are presented.

Experimental Study and Numerical Investigation of the Phenomena Occurring During Long Duration Cold Spray Deposition

Low Pressure Cold Spray process is a relatively new additive technique allowing to create high quality metallic coatings, through the high velocity spraying of particles, on both metallic and non-metallic substrates. The adhesion mechanism of the particles is, to date, not fully understood and the phenomena occurring during long depositions (which are the more interesting for industrial processes) are not known and studied in details. Aiming to fulfill this lack of knowledge, the phenomena occurring during long deposition were studied through both careful experimental evaluations and numerical approach. Particular attention was paid at the working conditions of the De Laval nozzle system which accelerates the particles, a computational fluid dynamics model focusing on both geometrical features and spray behavior was proposed. Micron-sized aluminum powders and compressed air as carrier gas were used in this experimentation, numerical simulations are performed to predict the gas flow regime. It has been found that the deposition efficiency tends to decrease due to the critical phenomena occur into the spray nozzle during long time depositions. The sprayed particles tend to stick to the walls of the nozzle and, moreover, shock waves occur inside the nozzle further promoting the particles stick phenomena, making the system inefficient.

Development of a New Punch Head Shape to Replicate Scale-Up Issues on a Laboratory Tablet Press III: Replicating Sticking Phenomenon Using the SAS Punch and Evaluation by Checking the Tablet Surface Using 3-D Laser Scanning Microscope

Sticking is a common observation in the scale-up stage on the punch tip using a commercial tableting machine. The difference in the total compression time between a laboratory tableting machine and a commercial one is considered one of the main root causes of scale-up issues in the tableting processes. The proposed “Size Adjusted for Scale-up punch” can be used to adjust the consolidation and dwell times for commercial tableting machine. As a result, the sticking phenomenon is able to be replicated at the pilot scale stage. As reported in this article, the quantification of sticking was done using a 3-D laser scanning microscope to check the tablet surface. It was shown that the sticking area decreased with the addition of magnesium stearate in the formulation, but the sticking depth was not affected by the additional amount of magnesium stearate. It is proposed that the use of a 3-D laser scanning microscope can be applied to evaluate sticking as a process analytical technology tool, and so sticking can be monitored continuously without stopping the machine.

Optimization of drying conditions and components to reduce wall sticking during spray drying of infant formula milk

Wall sticking, which greatly reduces productivity and product quality, has been a big challenge of spray drying. Structure of drying tower and atomizer, as well as drying conditions are the main influencing factors. This research explored the possibility to reduce wall sticking by optimizing drying conditions and components to obtain higher recovery rate of powdered infant formula milk (PIFM). Response surface experimental results indicated that inlet air temperature (T), feed concentration (C), feeding speed (S), as well as interaction term of TC and quadratic terms of C2 and S2 had significant influences on recovery rate for determined milk formula. According to mixture experiments at optimized drying conditions, whey protein (P), fat (F) and lactose (L) contents, as well as interaction term FL had significant effects on recovery rate. Positive effects were observed for F and L contents on recovery rate, while negative effects were observed for P and FL. Under the optimized drying condition of 136°C, 19.80% and 4.07 mL/min, respectively, for T, C and S, the maximum recovery rate of 58.98% was obtained for PIFM with P, F and L content of 18%, 31% and 51%, respectively. Wall sticking phenomena could be reduced by optimizing drying conditions and mildly adjusting components of infant formula milk. Keywords: spray drying, drying condition, wall sticking, inlet temperature, feed concentration, feeding speed, powder recovery rate, infant formula milk DOI: 10.25165/j.ijabe.20181102.2788 Citation: Lin Y W, Liu Y H, Wang L, Xie Y K, Gao Z J, Wang S J. Optimization of drying conditions and components to reduce wall sticking during spray drying of infant formula milk. Int J Agric & Biol Eng, 2018; 11(2): 214–218.

Parametric Investigation on Microstructure and Mechanical Properties of Ultrasonic spot welded Aluminium to Copper sheets

Ultrasonic welding is one of the promising solid state welding methods which have been widely used to join highly conductive materials like aluminum and copper. Despite these applications in the automotive field, other industries also have a strong interest to adopt this process for joining of various advanced alloys. In some of its applications, poor weld strength and sticking of the workpiece to the tool are issues. Thus, an attempt has been taken in the present study to overcome these issues by performing experiments with a suitable range of weld parameters. The major objectives of this study are to obtain a good joint strength with a reduced sticking phenomenon and microstructure of Al-Cu weld coupons. The results uncovered the mechanical strength of the joint increased up to 0.34 sec of weld time and afterward, it gradually decreased. Meantime, the plastic deformation in the weld zone enhanced the formation of an intermetallic layer of 1.5 μm thick, and it is composed of mainly Al2Cu compound. The temperature evolved during the welding process is also measured by thermocouples to show its relationship with the plastic deformation. The present work exemplifies a finer understanding of the failure behavior of joints and provides an insight of ultrasonic welding towards the improvement in the quality of weld.

Determination of the Frictional Behavior at Compaction of Powder Materials Consisting of Spray-Dried Granules

The frictional behavior during powder compaction and ejection is studied using an instrumented die with eight radial sensors. The average friction over the total powder pillar is used to determine a local friction coefficient at each sensor. By comparing forces at compaction with forces at ejection, it can be shown that the Coulomb’s friction coefficient can be described as a function of normal pressure. Also stick phenomena has been investigated in order to assess its influence on the determination of the local friction coefficient.

Sticking behaviour and mechanism of iron ore pellets in COREX pre-reduction shaft furnace

ABSTRACTCOREX is a clean process releasing lower pollution and consuming fewer cokes than the blast furnace process. However, serious sticking phenomenon often occurs in COREX shaft furnace, causing many problems to the normal operation. In this study, the loading reduction experiments of iron ore pellets were carried out under the simulating COREX reducing conditions. The influence of temperature and H2 content in the syngas on the sticking behaviour of the pellets was observed by scanning electron microscope, energy-dispersive spectrometer and X-ray diffraction. The results indicated that the sticking index increased from 6.7 to 90.43%, when the temperature increased from 750 to 950°C. The main composition of sticking material was metallic iron, and the sticking behaviour depended upon the amount and morphology of precipitated iron on the pellets’ surface. The sticking mechanism was the interpenetrating diffusion mechanism of iron atoms between the adjacent pellets.

The crucible/silicon interface in directional solidification of photovoltaic silicon

Photovoltaic silicon ingots are currently grown in silica crucibles coated with a porous silicon nitride layer which acts as an interface releasing agent between the silicon and the crucible. The interactions between Si and the Si3N4 coating determine the infiltration and sticking phenomena occurring at the interface and also affect the pollution of Si by the components of the coating. In this investigation the interfacial interactions and microstructure are studied in crystallization experiments performed in crucibles involving high silicon masses (tens of kg) and long contact time between the silicon and the coated silica (tens of hours). It is shown that for long times, a dramatic change in the nature of the coating/Si interface takes place, with the formation of a self-crucible which prevents the direct contact between the silicon and the coating. The stability of the self-crucible is modeled taking into account the capillary and hydrostatic pressures. The influence of the self-crucible on different practical aspects of the photovoltaic silicon crystallization process is discussed.

Toughening mechanisms and mechanical properties of graphene nanosheet-reinforced alumina

High-frequency induction heat sintering (HFIHS) technology was employed for fabrication of highly dense (>99.5%) graphene-reinforced alumina nanocomposites. The mixed powders were consolidated at temperatures up to 1500°C with 0.25 to 3.0wt.% exfoliated graphene nanosheets (GNS). Compared with monolithic alumina, there was grain size refinement by 46% with an associated increase in the fracture toughness (by 72%) and hardness values (7%). Electron microscopy revealed that exfoliated GNS retained their inherent planar structure against any possible chemical and/or thermal adverse effect caused by rapid sintering. The intrinsic 2-dimensional sheet morphology and flexibility of the GNS promoted formation of large Al2O3/GNS interfacial area, thus leading to a dominant reinforcing mechanism via grain anchoring. The presence of GNS at the grain boundary areas not only inhibited grain growth through pinning effect, it also modified friction traits at nanoscale level by inducing slip–stick phenomenon that increased the Al2O3/GNS interfacial strength by means of improved efficiency of graphene pull-out and crack-bridging that subsequently imparted toughness and altered the failure behavior of the composites. A possible correlation between GNS incorporation into Al2O3 matrix and the resulting mechanical properties is established through high-resolution TEM studies that indicated graphene/alumina interface formation without any presence of severe intermediate phases.

Effect of carbide size and spacing on the fretting wear behavior of Inconel 690 SG tube mated with SUS 409

The effect of carbide size and spacing on the fretting wear resistance of Inconel 690 steam generator (SG) tube mated with SUS 409 was investigated in this study. Based on previous materials tribology research, we reasoned that increasing carbide size and spacing would increase the wear resistance of the Inconel 690. Experiments were performed to test this hypothesis. Commercialized Inconel 690 tube with mean carbide length, thickness and spacing of 0.29, 0.10, and 0.59μm, respectively, was used for the wear test. Carbide length, thickness, and spacing increased to 0.36, 0.15, and 0.68μm, respectively after heat treatment at 450°C for 16h without changes in carbide volume fraction, grain size or hardness. The results of the wear test showed that at the amplitude of 25μm, wear coefficient did not change due to stick phenomenon. At the amplitude of 50μm–150μm, wear coefficient decreased about 50%. At the amplitude of 300μm, the wear coefficient decreased from 2.7×10−13m3/Nm to 2.0×10−13m3/Nm due to increase in carbide size and spacing.

Hockey Stick Phenomenon: Supply Chain Management Challenge in Brazil

The objective of this study is to investigate a phenomenon that occurs in Brazil, specifically the spike in demand at the end of the sales period, known as the hockey stick phenomenon. This analysis will encompass the causes as well as the impacts of this phenomenon, in a way that allows alternative policies to be evaluated. Data was collected from a Brazilian branch of a large multinational in the non-durable consumer goods industry and in semi-structured interviews conducted face-to-face with executives of 26 clients. The data was used to generate a continuous simulation model based on the methods of systems dynamics. The findings showed that the phenomenon negatively impacted the manufacturer’s financial performance in the long term and indicated required changes necessary to remediate the phenomenon. This is an empirical study on the hockey stick phenomenon, a problem that affects diverse companies in Brazil. The study showed that companies should not assume the hockey stick phenomenon to be an exogenous problem; it showed that there are policies able to improve financial performance; and it provided ideas regarding ways to carry out the change process.

气体放电对PDP残像形成的影响及其改善研究

气体放电对PDP残像形成的影响及其改善研究

Migration of tungsten dust in tokamaks: role of dust–wall collisions

The modelling of a controlled tungsten dust injection experiment in TEXTOR by the dust dynamics code MIGRAINe is reported. The code, in addition to the standard dust–plasma interaction processes, also encompasses major mechanical aspects of dust–surface collisions. The use of analytical expressions for the restitution coefficients as functions of the dust radius and impact velocity allows us to account for the sticking and rebound phenomena that define which parts of the dust size distribution can migrate efficiently. The experiment provided unambiguous evidence of long-distance dust migration; artificially introduced tungsten dust particles were collected 120° toroidally away from the injection point, but also a selectivity in the permissible size of transported grains was observed. The main experimental results are reproduced by modelling.

GW24-e0777 The observation of the fleabane injection clinical curative effect on the old patients with acute coronary syndrome

ObjectivesTo observe the fleabane injection clinical curative effect and security on the patients with acute coronary syndrome.MethodsWe divided 66 patients with acute coronary syndrome into 2 groups. The experimental group...

NIST and IEEE Challenge for MagPieR: The Fastest Mobile Microrobots in the World

Recent advances in micro/nanotechnologies and microelectromechanical systems have enabled micromachined mobile agents. Highly dynamic mobile microrobots are believed to open the gate for various future applications. However, at the submillimeter scale, the adhesion effects dominate physics, especially in the air environment. Although many studies have been performed to avoid or reduce this effect, the sticking phenomena are still one of the biggest challenges in achieving highly dynamic micromobile robots. Subsequently, intrinsic challenges at the given scale (hundreds of micrometers) are the powering technique themselves. Although often designed from active materials, actuation may only be performed by means of various external fields that often require a lot of space around the scene. In this context, the National Institute of Standards and Technology (NIST) and the IEEE initiated an annual state-of-the art microrobotics challenge, boosting the development of novel mobile agents with precise and highly dynamic propulsion mechanisms and controllability. During our first participation in this competition in 2010, the French team Centre National de la Recherche Scientifique (CNRS) proposed a magnetic and piezoelectric mobile microrobot called MagPieR, which dramatically enhanced the propulsion speed to 28 ms for the so-called 2-mm dash task. It literally cut the former record to a quarter. In the meantime, during the 2011 challenge, MagPieR won the mobility challenge thanks to some optimized coil setup and control law. The continuous technical advances in terms of dynamic performance are now shifting, and the focus of the next challenge is more agile-demanding and controllable tasks. Combining different physical effects is a promising key for the future of highly dynamic mobile microsystems and associated applications in micromanipulation, microassembly, or minimally invasive surgery.

Squeak and rattle noise prediction for trimmed door of a car using hybrid statistical energy—Finite element method analysis

Squeak and rattle (S&R) noise are important in-cabin sources of annoyance for occupants. Originally, S&R is generated as a result of colliding and slamming of car’s trim and body structure, which in turn occurs because of the dynamic displacements of components excited by road and powertrain. Squeak noise is interpreted as periodic stick and slip phenomena in the contact boundary of two neighbor surfaces. While rattle noise is the emitted noise when adjacent surfaces collide and impact. Both squeak and rattle phenomena happen in high-frequency range, even though the excitation sources (road and powertrain line) works in low frequency range. In practice, squeak and rattle noise can be minimized via controlling the gaps through a tolerance analysis, as well as the appropriate choice of materials. In this research, potential S&R sources are investigated for the trimmed door of a car using clearance analysis. Impact statistics and overall force level at potential rattle places are calculated through random vibration excitation analyses and afterwards, acoustic sensitivity, overall acoustic response, and loudness are calculated by the aim of hybrid SEA-FE method. The results of this prediction will be used in noise and vibration control plan of the whole car in design phase.

A review of tool–chip contact length models in machining and future direction for improvement

Tool–chip contact length can be a critical parameter in machining as it provides the path for heat flow from the secondary deformation zone into the tool. This is particularly critical in dry or high-speed machining, where elevated temperatures can activate wear mechanisms and hence reduce tool life. A number of analytical, dimensional analyses, empirical and statistical models have been used to predict contact length. However, more research is required to significantly raise the model accuracy in quantitative prediction and to elucidate the mechanisms that control contact length. In this study, cutting tests were performed at cutting speeds ranging from conventional to high cutting speed, and tool–chip contact length, chip thickness, sticking and sliding contact phenomena and cutting forces were characterised. Twenty-two contact length models reported in the literature were evaluated and benchmarked to experimental data. While dimensional analysis–based models have an improved quantitative predictive capability, they do not provide comprehensive insight into contact phenomenon. To this end, this work builds upon Tay et al.’s contact length model that has been benchmarked as promising in the literature. Parameters that influence the contact area, in particular, tool–chip sticking phenomenon, were characterised. Suggestions for improving contact length modelling are proposed.

Research on the anti‐sticking characteristics of water hydraulic piston friction pairs with hydrostatic bearing

ABSTRACTCertain sticking phenomena generally exist in the common clearance sealing piston friction pairs. For oil media, it can be accepted because of its better lubrication, but for water media, it needs to be avoided as far as possible because of its worse lubrication. In this paper, the piston pairs with the hydrostatic bearing are presented to improve its anti‐sticking ability. The anti‐sticking performance is researched by computational fluid dynamics and experiment. The results indicate that the anti‐sticking ability can be improved for the new structure piston pairs. The key reason is that the hydrostatic bearing effect is reasonably applied. Copyright © 2012 John Wiley & Sons, Ltd.

Stochastic Analysis of the Wheel-Rail Contact Friction Using the Polynomial Chaos Theory

The coefficient of friction (CoF) is a very important factor for designing, operating, and maintaining the wheel-rail system. In the real world, accurate estimation of the CoF at the wheel-rail interface is difficult due to the effects of various uncertain parameters, e.g., wheel and rail materials, rail roughness, contact patch size, and so on. In this study, a stochastic analysis using polynomial chaos (poly-chaos) theory is performed with the newly developed 3D dry CoF model at the wheel-rail contact. The wheel-rail system is modeled as a mass-spring-damper system. Stochastic analyses with one uncertainty, combinations of two uncertainties, and a combination of three uncertainties are performed. The probability density function (PDF) results for stick CoF, slip CoF, and combined (total) CoF are presented. The stochastic analysis results show that the total CoF PDF before 1 s is dominantly affected by the stick phenomenon, whereas the slip dominantly influences the total CoF PDF after 1 s. The CoF PDFs obtained from simulations with combinations of two and three uncertain parameters have wider PDF ranges than those obtained for only one uncertain parameter. The current work demonstrates that the CoF is strongly affected by the stochastic variation of dynamic parameters. Thus, the PDF distribution of the CoF could play a very important role in the design of the wheel-rail system.