Sticking Problems Research Articles

Oxide scale on stainless steels and its effect on sticking during hot-rolling

The failure of oxide scales on ferritic stainless steels (STSs) has been known to cause an unexpected and severe sticking problem during the hot-rolling process. The oxide scale fragments formed during hot-rolling are stuck on the surfaces of the working roll, deteriorating the surfaces of both the roller and the rolled materials. In this study, we investigate the effects of the compositions and microstructures of thermally grown oxide scales on the degree of sticking during hot-rolling in three different kinds of commercial ferritic STSs and one austenitic STS. The STS samples are oxidized at around 1280 °C for 2 h, and the oxide scales formed on the STSs are identified by X-ray diffraction (XRD). Additionally, the cross-sectional microstructure and chemical compositions of the oxide scales on the STSs are examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM), respectively. The oxide scales adjacent to the interfaces with the bulk STS are analyzed by high-resolution transmission electron microscopy (HR-TEM). The Gleeble test, which is a high-temperature (1250 °C) tensile test, is conducted to analyze the effects of the stress induced in the oxide scales during hot-rolling on the fracture of the scales. According to the microstructural analysis and mechanical test results, a brittle Cr2O3 layer, where cracks are easily formed and propagate through the scale thickness under the stress induced by hot-rolling, is formed along the interfaces of STSs with high Cr contents. This effect increases the probability of sticking failure in high-Cr STSs. In contrast, scales with a composite-like structure of Fe- and Cr-oxides are formed on the surface of STSs containing low and medium levels of Cr. According to the Gleeble test results, the composite-like oxide scales show higher mechanical resistance to tensile stress than the Cr2O3 layers in the high-Cr STSs. In addition, our microstructural analysis results reveal that FexNiy intermetallic compounds are observed as a form of a composite-like structure inside the oxide scales in the austenitic STS and that this structure also delays crack propagation through the oxide scales and reduces the degree of sticking.

Corrosion behavior of Al2O3 substrate by SiO2–MgO–FeO–CaO–Al2O3 slag

Alumina–based refractory is widely used as lining material of rotary hearth furnace (RHF) in the direct reduction process. However, corrosion of refractory by the burden is a crucial problem which affects the RHF production. In this study, a sessile drop technique was used to investigate the wetting and corrosion behavior of Al2O3 substrate against SiO2–MgO–FeO–CaO–Al2O3 slag, whose composition was determined according to the slag obtained from smelting nickel laterite in the RHF process. The experimental results showed that the slags with basicity ((MgO+CaO)/SiO2) of 0.43 and 0.63 had a low apparent contact angle of approximately 25° and 30°, respectively. It indicated the slag samples could wet well on the Al2O3 substrate. The spreading of slag on the substrate was mainly ascribed to the decrease of surface tension at the initial stage. As the wetting process proceeded, Al2O3 dissolved into the slag forming an interfacial layer which gradually covered the substrate surface under the droplet and inhibited further dissolution of Al2O3. Good wettability and the dissolution of Al2O3 are two main factors that caused the corrosion of substrate. Separating the burden from the Al2O3 substrate was restrained after cooling, which would possibly bring severe sticking problems between the burden and alumina refractories.

Prevention of sticking during surface casing drilling in Samotlorskoye field

The paper considers the current problem of sidewall sticking during surface casing in Samotlorskoye field. The analysis of geological and field material was carried out and the reasons for sticking during drilling of upper unstable argillaceous deposits of Lulinvorskaya, Talitskaya and Gankovskaya suites were determined. It is found that in most well construction projects, the inhibitory agents preventing clay hydration are used in drilling muds. The authors studied the mechanisms of shale inhibition. The results of experimental studies on the impact of various inhibitor additives on clay samples demonstrated the efficiency of Polysil and Osnova GS (hydrophobizated fluid) additives with sulphoacid. The results of the analysis made it possible to make proposals and recommendations to prevent sticking.

Reduced Punch Sticking Propensity of Acesulfame by Salt Formation: Role of Crystal Mechanical Property and Surface Chemistry.

Powder adhesion or sticking onto punches is one of the outstanding issues in pharmaceutical tablet manufacturing. We show in this work that, at comparable particle sizes, the acesulfame potassium exhibited pronouncedly reduced propensity to punch sticking than acesulfame. Detailed analyses revealed strong correlation between sticking propensity and crystal mechanical properties and surface chemistry. The free acid was highly plastic with high cohesive strength, while the salt form was brittle. During compaction, surfaces of acesulfame in contact with the punch face are abundant in electronegative functional groups, while those of the salt consist of mainly hydrophobic groups. Thus, acesulfame underwent stronger interactions with the electron-deficient punch. Consequently, the strikingly different onset and severity of sticking propensity between the two solid forms of acesulfame could be clearly explained based on their different crystal mechanical properties and surface characteristics. By providing molecular insight into the outstanding problem of punch sticking in tablet manufacturing, this work expands the list of pharmaceutical applications of crystal engineering.

Investor Sentiment and the Basis of CSI 300 Stock Index Futures: An Empirical Study Based on QVAR Model and Quantile Regression

The asymmetrical mutual influence of investor sentiment and the basis of CSI 300 stock index futures under conditions in different market situations was investigated using the quantile vector autoregressive model (QVAR). The article also discussed asymmetrical influence of investor sentiment on the basis under conditions in different investor structures using the quantile regression method. On this basis, we obtained several important conclusions: (1) There exists a one-way causal relationship where investor sentiment has a significant impact on the CSI 300 stock index futures basis in China; the investor sentiment is likely to exert stronger influences on the basis in the chaotic period of the stock market and imposes significant asymmetrical effects. (2) The institutionalized development of investors can reduce the influences of investor sentiment on the basis when the stock market is stable, while it does not play its function in stabilizing the capital market when the stock market is in turmoil. (3) The low institutionalization level, the individualization of institutional investors, and the imperfect short-sales mechanism as a whole are still the sticking problems in the immature capital market of China.

Improving anti-adhesion performance of electrosurgical electrode assisted with ultrasonic vibration

The electrosurgical electrode currently stands out as one of the most commonly used tools in minimally invasive surgery. In order to facilitate tissue cutting and accelerate wound healing, tissue adhesion to the electrosurgical electrode is considered as an extremely urgent problem to be solved. In this paper, a novel ultrasonic vibration assisted (UV-A) electrosurgical electrode is firstly proposed to overcome the problem of tissue sticking. The anti-adhesion effects were evaluated by measuring the adhesion force and the weight of tissue adhesion using the electrosurgical electrode with and without UV-A comparatively. Experimental results show that the average adhesion force and the tissue adhesion mass with UV-A were decreased by approximately 60% and 70% respectively, accompanied by smaller thermal injury area compared with that without UV-A. Moreover, the underlying mechanism of anti-adhesion effect with UV-A was revealed by investigating the influence of ultrasonic vibration on electric current, tissue removal and spark discharge. This research suggests that UV-A is a promising and practical method for improving the anti-adhesion performance of electrosurgical electrode.

Scanning Electron Microscope Observations of Powder Sticking on Punches during a Limited Number (N

To obtain quantitative information and mechanistic insight into the problem of sticking of acetylsalicylic acid tablets on a metallic punch. Low voltage scanning electron microscopy was used to observe punch area coverage and morphology of adhered powder on a flat punch used for a limited number of compactions. Material accumulation in terms of area coverage of the punch per compaction cycle was determined at two pressures over five compactions. The distribution of the adhered material on the punch was non-uniform with more material left on the center of the punch. The sizes of the adhered particles range from 1 to 100μm, with 50% of the punch surface coverage from particles of an equivalent diameter>30μm. Three types of adhered particles were identified after the first compaction: (a) fragments of initial particles with very high aspect ratio, (b) nearly equiaxed fragments with multiple cracks, (c) heavily deformed islands of low profile. Some preliminary ideas that explain these observations are presented and discussed. The ability of SEM to provide quantitative information on sticking from few compactions presents an interesting possibility for a material sparing technique that provides insight on the propensity of sticking.

Powder properties and compaction parameters that influence punch sticking propensity of pharmaceuticals

Punch sticking is a frequently occurring problem that challenges successful tablet manufacturing. A mechanistic understanding of the punch sticking phenomenon facilitates the design of effective strategies to solve punch sticking problems of a drug. The first step in this effort is to identify process parameters and particle properties that can profoundly affect sticking performance. This work was aimed at elucidating the key material properties and compaction parameters that influence punch sticking by statistically analyzing punch sticking data of 24 chemically diverse compounds obtained using a set of tooling with removable upper punch tip. Partial least square (PLS) analysis of the data revealed that particle surface area and tablet tensile strength are the most significant factors attributed to punch sticking. Die-wall pressure, ejection force, and take-off force also correlate with sticking, but to a lesser extent.

Order Statistics of Horse Racing and the Randomly Broken Stick

We find a remarkable agreement between the statistics of a randomly divided interval and the observed statistical patterns and distributions found in horse racing betting markets. We compare the distribution of implied winning odds, the average true winning probabilities, the implied odds conditional on a win, and the average implied odds of the winning horse with the corresponding quantities from the “randomly broken stick problem”. We observe that the market is at least to some degree informationally efficient. From the mapping between exponential random variables and the statistics of the random division we conclude that horses’ true winning abilities are exponentially distributed.

Study on thermal induced preload of ball bearing with temperature compensation based on state observer approach

The internal contact feature and thermal induced dynamic preload is essential for ball bearing, which is one of the key issues for thermal instability and stuck problems at high rotation speed. This paper presented a thermo-mechanical coupling model for angular contact ball bearing with preload and temperature compensation, for the purpose of dynamic preload monitoring. Based on the verified thermal balance equations, thermal deformation and thermal induced preload were achieved and feedback to the original local approach of heat generation calculation. Then, the nonlinearity and uncertainty heat transfer characteristic was considered via a state observer to verify the calculation process. The state variable of bearing’s temperature rise was defined and a state observer with proportional-integral term was designed. The difference between experimental data and calculation result was feedback by the observer to control the heat transfer and preload solving process. Thus, the real-time temperature rise, thermal deformation, and dynamic preload of bearing’s internal assemblies were obtained.

Successful New Inhibitive Water-Based Fluid Application, Sulige Gas Field, China

This study developed a new type of shale drilling anti-collapse inhibitor and compounded a set of stable shale water-based drilling fluid for horizontal wells to effectively solve hole shrinkage, collapse, tool sticking, and other complex downhole problems involved in the shale drilling at the horizontal section of the Sulige gas field. Laboratory experimental evaluations indicated that this system had a strong inhibitory effect on shale formation and sound compatibility. After its weight reached 1.20g/cm3, the system exhibited a stable rheology, lubricity, filter loss, high recovery rate of rock debris, and low formation damage. The mud cake was smooth, thin, tough, and compact. The drilling fluid also maintained suitable anti-collapse capability, lubricity, rheology, and highly efficient debris-carrying and well-flushing ability in its field application in the drilling of the shale section of the Sulige gas field. The tripping operation exhibited no clear resistance and sticking. This system achieved significant effects and satisfied the requirements of the drilling construction of a horizontal well in the Sulige gas field.

Treatment practice of sloughing and sticking in offshore deep wells with complex trajectories

A majority of adjustment wells drilled in eastern parts of South China Sea are characterized by big depth and complex borehole trajectory. In case of sticking incidents, forces for stuck releasing may not be transferred effectively, consequently, stuck releasing operations in these wells may involve huge difficulties. By analyzing root causes of sticking incidents in Well A in the offshore Lufeng 13-1 Oilfield in the paleogene enping formation, techniques such as stuck releasing through circulation and gradual lifting with minor discharging volumes have been developed to release stuck drilling tools effectively. These newly developed technologies may serve as fast and highly effective ways to remove problems related to sloughing and sticking in the area. In addition, these techniques may provide necessary guidance for dealing with sloughing and sticking problems in wells with similar conditions.

Micro/nanostructured surface modification using femtosecond laser pulses on minimally invasive electrosurgical devices.

The purpose of the present study was to examine thermal damage and a sticking problem in the tissue after the use of a minimally invasive electrosurgical device with a nanostructured surface treatment that uses a femtosecond laser pulse (FLP) technique. To safely use an electrosurgical device in clinical surgery, it is important to decrease thermal damage to surrounding tissues. The surface characteristics and morphology of the FLP layer were evaluated using optical microscopy, scanning electron microscopy, and transmission electron microscopy; element analysis was performed using energy-dispersive X-ray spectroscopy, grazing incidence X-ray diffraction, and X-ray photoelectron spectroscopy. In the animal model, monopolar electrosurgical devices were used to create lesions in the legs of 30 adult rats. Animals were sacrificed for investigations at 0, 3, 7, 14, and 28days postoperatively. Results indicated that the thermal damage and sticking situations were reduced significantly when a minimally invasive electrosurgical instrument with an FLP layer was used. Temperatures decreased while film thickness increased. Thermographic data revealed that surgical temperatures in an animal model were significantly lower in the FLP electrosurgical device compared with that in the untreated one. Furthermore, the FLP device created a relatively small area of thermal damage. As already mentioned, the biomedical nanostructured layer reduced thermal damage and promoted the antisticking property with the use of a minimally invasive electrosurgical device. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 865-873, 2017.

Trending Challenges in Multi Label Classification

Multi label classification has become a very important paradigm in the last few years because of the increasing domains that it can be applied to. Many researchers have developed many algorithms to solve the problem of multi label classification. Nerveless, there are still some stuck problems that need to be investigated in depth. The aim of this paper is to provide researchers with a brief introduction to the problem of multi label classification, and introduce some of the most trending challenges.

MEMS switch with the active contact breaking mechanism

Electrostatically actuated MEMS switch with resistive contact is presented. Movable electrode of the switch is a beam suspended by torsion springs. Low stiffness of springs allows to achieve the low values of the actuation voltage. Main feature of the switch is a mechanism of the active contact breaking, allowing to solve the problem of adhesive sticking of the beam to the signal electrode. The active opening of the switch is realized by the presence of two driving electrodes. The theoretical analysis, finite element simulation and experimental investigation of the switch characteristics are performed.

Dependence of ejection force on tableting speed—A compaction simulation study

Using a compaction simulator, it has been shown that tablet ejection force increases with increasing tableting speed during compression of powders lubricated with 1% magnesium stearate. Faster tableting speed corresponds to higher coefficient of friction, μ, but does not affect residual radial die wall (RDW) stress. The higher μ suggests the presence of less lubricant at the tablet–die wall interface due to the shorter time available for migration of lubricant to the interface. This mechanism can also explain the sudden occurrence of powder sticking problem upon formulation scale up. The elevated ejection force due to higher μ also results in higher RDW stress at the moment of slip initiation, which proportionally increases ejection force.

Fabrication process of a microstructures based on hydrogenated amorphous SiGe films for applications in MEMS devices

We present a fabrication process of microstructures using both boron-doped hydrogenated amorphous silicon and hydrogenated amorphous silicon-germanium (a-SiB:H and a-Si0.5Ge0.5B:H) films for applications in devices based on microelectromechanical systems (MEMS). These microstructures are fabricated through plasma enhanced chemical vapor deposition (PECVD) with a low temperature of 300°C at 110 kHz and a pressure of 0.6 Torr. The proposed microstructures have three different geometries (Diamond, cantilever and bridge) considering a single structural layer of 1 μm thickness and are fabricated using surface micromachining. The fabricated a-Si0.5Ge0.5B:H microstructures do not present sticking problems and have good mechanical stability, which can allow their use in MEMS devices. Our fabrication process with hydrogenated amorphous SiGe films is simple. This process decreases the residual stress of the microstructures and allows the metal deposition on the microstructures surfaces.

An improved bee colony optimization algorithm with an application to document clustering

The bee colony optimization (BCO) algorithm is proved to be one of the fast, robust and efficient global search heuristics in tackling different practical problems. Considering BCO algorithm in this paper, we utilize it for the data clustering, a fundamental problem that frequently arises in many applications. However, we discovered some obstacles in directly applying the ancient BCO to address the clustering problem and managed to change some basic behaviors of this swarm algorithm. In particular, we present an improved bee colony optimization algorithm, dubbed IBCO, by introducing cloning and fairness concepts into the BCO algorithm and make it more efficient for data clustering. These features give BCO very powerful and balanced exploration and exploitation capabilities to effectively guide the search process toward the proximity of the high quality solutions. In particular, the cloning feature allows it to take advantage of experiences gained from previous generations when generating new solutions. The problem of getting stuck in local optima still laid bare in the proposed improved version. As a result, to overcome the shortage of this swarm algorithm in searching locally, we hybridize it with the k-means algorithm to take advantage of fine tuning power of the widely used k-means algorithm which demonstrates good result in local searches. We propose four different hybridized algorithms based on IBCO and k-means algorithms and investigate the clustering results and convergence behavior of them. We empirically demonstrate that our hybrid algorithms alleviate the problem of sticking in a local solution even for large and high dimensional data sets such as document clustering. The results show that proposed algorithms are robust enough to be used in many applications compared to k-means and other recently proposed evolutionary based clustering algorithms including genetic, particle swarm optimization, ant colony, and bee based algorithms.

Interfaces of Molecular Recognition Sites and Biosensors; Novel Bio-Sensing Materials

ABSTRACTWe introduce a sensing element, “Molecularly Imprinted Polymer (MIP),” which created by “Molecular Imprinted Technique.” However, the sensitivity of MIP’s based bio-sensors limits for practical applications due to the low sensitivity. To achieve a high sensitivity of MIP’s based sensors, the synthesis of “high affinity receptor or binding sites,” such as “monoclonal particles” is a key objective. In previous studies, affinity distribution plots indicated that “high affinity binding sites” were obtained when the number of binding sites per particle decreased. It means that smaller particles are expected to have higher affinity binding sites compared to larger particles. The result motivated us to produce small-sized MIP’s particles for the achievement of higher sensitivity. Microfluidic Synthesis has taken a great attention to synthesize small particles. However, the microfluidic synthesis gave us a difficulty, especially collections of MIP’s particles from the surface of PDMS-based microchannels due to a sticking problem. Thus, we employed a new approach, which can collect MIP’s particles without any sticking problem from the surface of the reactor. It is a photopatterned MIP’s system generated on the glass surface. We prepared a photomask with micro-sized patterns and then fabricate MIP’s particles on a glass surface by photopolymerization. Uniform MIP’s patterns were printed on the glass surface. The interface between the glass surface and the MIP’s pattern was observed by SEM. Micro-sized MIP’s particles were collected from the glass surface by scratching off the photocured MIP’s patterns.

Charge-tunable absorption behavior of DNA on graphene.

Solving the problem of DNA sticking to graphene is very important for the use of graphene in DNA sequence or other DNA sensor technology. In this study, we use molecular dynamics simulation to demonstrate that DNA tends to adsorb on pristine neutralized graphene rather than on graphene with negative charge. This property of graphene could be charge-tuned from DNA-philic to DNA-phobic, and the property is evaluated by the contact angle of DNA absorbed the on graphene surface. With a negative charge, graphene is prone to be DNA-phobic; with a positive charge, or without a charge, it is likely to be DNA-philic. The translocation time of DNA on a graphene nanopore was greatly extended if the graphene nanopore is functionalized by a negative charge. This study could help us to better design a promising device for DNA sequencing by graphene nanopores.