Sticking Problems Research Articles

A Multiple Integration Approach to the Broken Stick Problem with Predetermined Minimum Piece Lengths

Summary Not many mathematical problems can be successfully introduced around a dinner table or in other social settings, but a quick internet search tells us that broken stick problems are among the classics that still engage. The fact that solutions may require basic knowledge of calculus, probability, and combinatorics helps demonstrate the power and necessity of mathematical formalism. In this article, the general intention has been to show how multiple integrals calculate probabilities in relation to polygons made by pieces from a randomly broken stick of unit length. Most of this article is devoted to proving a probability formula for the case where side lengths have predetermined lower bounds. This formula generalizes a well known corresponding formula without these requirements.

Measurement method of the RDC for the IPS and FFS-LCD.

The residual direct current (RDC) almost always brings serious image sticking (IS) problems in LCDs and is mainly related to the liquid crystal (LC) and photoaligned polyimide. In this paper, we propose a novel method, to the best of our knowledge, to evaluate the RDC of the FFS-LCDs through an optical measurement system. By this means, the accumulation and release of the ions can be seen distinctly through the transmittance-time curves with the voltage regulation. Hence, it is helpful to compare and analyze the RDC problem of different displays. Moreover, this method possesses the advantage of high efficiency and simplicity in order to benefit the material design in photoaligned polyimide or the LC.

PIPE STICKING PROBLEMS AND THEIR SOLVING WAYS IN WELLBORE

In this article, we discuss the most common pipe sticking problems that occur in general drilling, explore their causes, and practices for solving and preventing them. Although there are various causes of drilling problems, they are mainly related to the drilling fluid, whose characteristics and optimization can help prevent/reduce a number of problems encountered during drilling and save a lot of money. Drilling fluids have undergone major changes since they were first used in the drilling process, leading to more optimal drilling. Its transformation from a simple mixture of water and clay to a more complex combination of various types of organic and inorganic additives has increased the fluid's rheological properties and filtration capabilities. Keywords: pipe sticking, free pipe, differential pressure stuck, drilling fluid, mud cake.

Potential drilling hazards for wells targeting the Cane Creek shale, Pennsylvanian Paradox Formation, Paradox fold and fault belt, southeastern Utah and southwestern Colorado

The Cane Creek shale of the Pennsylvanian Paradox Formation represents a major target for oil and gas in the Paradox fold and fault belt of the northern Paradox Basin of southeastern Utah and southwestern Colorado. Early exploration and development attempts resulted in blowouts due to unexpected gas-bearing intervals and casing collapses caused by salt flowage in the Paradox Formation. These problems represent some of the types of drilling hazards that could be expected when planning Cane Creek wells. Horizontal drilling first used in the early 1990s changed the Cane Creek shale play from one of mostly drilling failures to a more successful commercial play. Depending on the location, exploratory Cane Creek wells may penetrate a section that ranges in age from Cretaceous through Pennsylvanian. Drilling in the region often encounters a wide variety of lithologies (carbonates, shale, mudstone, sandstone, and evaporites) and associated potential hazards that may include: (1) swelling clays, (2) high porosity-permeability or fractured zones resulting in lost circulation or excessive mudcake buildup, (3) “kicks” due to the influx of reservoir fluid (oil, water, or gas) into the wellbore, (4) uranium-rich zones, (5) washouts, (6) hole deviation, sticking, and other well-integrity problems, (7) chert, and (8) overpressured intervals. In addition, natural carbon dioxide, which flows from the partially human-made Crystal Geyser near some Cane Creek wellsites, represents an unusual drilling hazard if encountered in the northernmost part of the fold and fault belt. Using the lessons learned from the recently completed research well, State 16-2 (renamed the State 16-2LN-CC, API No. 43-019-50089, after the horizontal leg was drilled), and other wells in the region, drilling engineers and operators can better plan for potential hazards when exploring for hydrocarbons in the Cane Creek shale or deeper targets (Mississippian Leadville Limestone and Devonian Elbert Formation) in the fairly remote, relatively sparsely explored Paradox fold and fault belt. The goal is to de-risk wells, lower expenses, and mitigate problems before they occur. The expected results are safer and more successful drilling of wells to the Cane Creek shale and deeper reservoirs ultimately leading to additional commercial hydrocarbon discoveries in the region.

Effect of Cutting Fluid on Milled Surface Quality and Tool Life of Aluminum Alloy

The machining process of aluminum alloy usually produces built-up edge and tool sticking problems due to their low hardness and large plastic deformation, which may further affect the machined surface quality and tool life. This paper aims to investigate the influence of different cutting fluids on the machined surface quality and tool life during the milling process of 7050 aluminum alloy. A novel cutting fluid (QC-2803) was considered in the study, which is synthesized by addition of alkyl alcohol amide and chlorinated polyolefin, and the traditional cutting fluid (CCF-10) was used as the control group. The physical and chemical properties of two cutting fluids were characterized. The milling process of 7050 aluminum alloy was carried out under two different cutting fluid conditions. The machined surface morphology, cutting force and tool wear morphology were observed during the process. Results show that the surface tension of the novel cutting fluid is significantly lower than that of the traditional cutting fluid, which makes it easier to produce a lubricating film between the aluminum alloy and tool, and further benefits the machined surface quality and tool life. As a result, the surface roughness and cutting force are reduced by ~20.0% and ~42.9%, respectively, and the tool life is increased by 25.6% in the case of the novel cutting fluid (QC-2803). The results in this paper revealed the important laws of cutting fluid with metal surface quality, cutting performance and tool wear, which helps to control the machined surface quality and tool life by the selection of cutting fluid during metal milling.

An effective optimization method for solving the relay coordination problem of the microgrids

In this work, an opposition-based learning-aggrandized class topper optimization (OBL-ACTO) algorithm is proposed to optimize the operating time of directional overcurrent relays (DOCRs) for an integrated microgrid power distribution network. The proposed OBL-ACTO algorithm is a hybridized method. In this method, an opposition-based learning (OBL) strategy is employed to tackle the local sticking problem of the traditional ACTO method and ameliorate its exploration and exploitation capability. The effectiveness of OBL-ACTO in solving the optimum coordination problem of (DOCRs) is tested on the IEC microgrid system and the 33kv distribution part of a standard IEEE 30-bus system. The proposed method along with the system is executed on the LabVIEW©2015 platform. The effectiveness of the developed method is shown based on the acquired optimal solution by comparing it with recently developed optimization methods for DOCRs problem. The proposed approach reduces the total operating time by 22.827 to 73.819 % to the compared methods. In addition, a non-parametric statistical hypothesis test is performed to show the proposed method’s significance based on the obtained simulation results.

AUTOMATIC OIL SHELL EJECTION

The purpose of this project is to investigate and solve the problem of sticking between die and sheet metal in a punch press. Initially, the problem was thought to be caused by high pressure, but lowering the pressure did not fix the problem. Further investigation revealed that the sticking was due to the magnetic properties of the die. demagnetizing the die with a demagnetizer has been found to be an effective solution. Another proposed solution is to apply a Tin coating to the die surface to prevent sticking. The aim of this project is to provide an effective solution to reduce sticking in punch presses.

Some Generalizations of Random Broken and Pick-up Stick Problems

We consider sticks with random lengths, which are further randomly broken into several pieces. The probability that these sticks can form a polygon is computed in this article. This Broken Pick-up Stick Problem was first asked in [1] and we give a general formula to solve this problem. Besides, we study the probability that any three sticks with independent and uniformly distributed lengths can form a triangle. Our results generalize the famous Spaghetti Problem and the Pick-up Stick Problem in probability. We present a way to transfer these continuous probability problems into discrete problems and apply combinatorial methods to address the discrete version of the problems.

Water Source Heat Pump’s Stuck Problems and Solutions

This paper analyses the water source heat pump’s normal stuck reasons, and test each of them. Identify the main reasons of the stuck pump is pump mechanical seal dynamic ring and static ring binding problems. (Poor water quality, water calcium carbonate, magnesium carbonate grind through the dynamic and static ring, after a long time stop, static ring long force extrusion contact, static ring binding surface molecular diffusion migration adhesion), due to the two rings’ binding, rotating torque beyond the motor starting torque, make the motor can’t start normally. This paper aims to find the real cause of the dynamic ring absorption, and put forward subsequent rectification measures to prevent recurrent stuck.

Mechanism of and Key Technologies for Copper Bonding in the Hot Rolling of SCR Continuous Casting and Rolling

In the process of copper alloy hot continuous rolling, the problem of copper sticking to the roller seriously affects the surface quality, performance, and service life of the copper products. Roll sticking occurs as the adhesion energy of Cu is lower than that of Fe and the Fe-Cu interface, and the severe surface deformation which forces the copper into direct contact with the roll during the process of profile rolling. Based on the copper deformation law and adhesion phenomenon in the hot continuous rolling process, a rolling deformation model and roll copper adhesion model or copper alloy hot continuous rolling were established, and their simulation was realized using finite element software. Through finite element modeling of the hot rolling deformation zone, the distribution of the temperature, contact normal stress, and exposure rate in the hot rolling deformation zone were obtained, which were consistent with the actual roll adhesion phenomenon and copper adhesion position. To address the copper sticking behavior of the rolls, the process optimization method of matching the motor speed with the elongation coefficient (the 1# and 2# motor speeds were adjusted to 1549 r/min and 1586 r/min, respectively), adjusting the roll gap to 7.9 mm, and increasing the number and pressure of roll spray nozzles were put forward, which effectively solved the problem of copper sticking to the roll, significantly improved the surface quality of the copper and the service life of the roll, and can be used in production.

Elucidation of LiCl encapsulated Bridgman growth of AlSb crystal

Aluminum antimonide (AlSb) possessing an indirect bandgap of 1.6 eV at room temperature offers a good option as a room-temperature dual-carrier radiation detector. However, the growth of AlSb crystal suffers from high reactivity of Al, causing sticking problems and polycrystallinity. Our work demonstrates experimentally that LiCl fully encapsulated Bridgman growth of AlSb is possible from near-stoichiometric AlSb melt. This leads to avoiding the interaction between the pyrolysis Boron Nitride (pBN) crucible and the melt, drastically decreasing nucleation on the peripheral crucible. Additionally, optimizing the melt composition and growth parameters provided a full understanding of LiCl encapsulated Bridgman growth of AlSb. Adding a slight amount of extra Sb into the stoichiometric AlSb melt can reduce the surface tension of the melt and enhance the stability of LiCl encapsulation efficiency. Conversely, it can also raise the risk of constitutional supercooling and promotes macroscopic defect formation. Accordingly, an optimized process was employed to obtain inclusion-free AlSb crystals with large grains (over 5 × 5 mm2) and homogeneous stoichiometric composition.

Tribological behavior comparisons of high chromium stainless and mild steels against high-speed steel and ceramics at high temperatures

High-temperature tribology, which is often involved during hot metal forming, is controlled via oxidation on a rubbing surface. However, for high chromium stainless steel (ST), where oxidation is strongly inhibited, the effect of counterface materials on tribological behavior is yet to be elucidated. In this study, the effects of counterfaces on the tribological behavior of 253MA ST and mild steel (MS) are investigated via a ball-on-disc test at 900 °C using a 20 N load. The results reveal that high-speed steel (HSS) experiences severe abrasive wear with MS and causes severe sticking problems with ST. Si3N4 and SiC present substantially stronger abrasive wear resistance than HSS with MS, and the friction coefficients are dependent on the type of ceramic. Both ceramics can facilitate the establishment of a thick tribo-oxide layer (> 3 µm) on ST to prevent sticking; however, this is accompanied by severe pull-out and fracture wear. The effects of the counterface on the mechanical properties of the tribo-oxide layer, near-surface transformation, and the responses of the tribo-oxide layer to friction and wear are discussed. This study contributes to the understanding of interfacial tribological behaviors when different types of tools are used on MS and ST.

DƏRİN QAZMA PROSESİ ZAMANI BAŞ VERƏN BORU TUTULMASI PROBLEMLƏRİ

The aricle is about the pipe stick problems of deep well drilling. Pipe stick problem is one of the drilling problems. There are two types of pipe stick problems exist. One of them is differential pressure pipe sticking. Another one of them is mechanical pipe sticking. There are a lot of reasons for pipe stick problems. Indigators of differential pressure sticking are increase in torque and drug forces, inability to reciprocate drill string and uninterrupted drilling fluid circulation. Key words: pipe stick, mecanical pipe stick,difference of pressure, drill pipe, drilling mud, bottomhole pressure, formation pressure

Four-point dynamic leveling method for drilling platform application

PurposeIt is essential to level the drilling platform across which a drilling robot travels in a slant underground coal mine tunnel to ensure smooth operation of the drill rod. However, existing leveling methods do not provide dynamic performance under the drilling conditions of the underground coal mine. A four-point dynamic leveling algorithm is presented in this paper based on the platform attitude and support rod displacement (DLAAD). An experimental drilling robot demonstrates its dynamic leveling capability and ability to ensure smooth drill rod operations.Design/methodology/approachThe attitude coordinate of the drilling robot is established according to its structure. A six-axis combined sensor is adopted to detect the platform attitude, thus revealing the three-axis Euler angles. The support rod displacement values are continuously detected by laser displacement sensors to obtain the displacement increment of each support rod as needed. The drilling robot is leveled according to the current support rod displacement and three-dimensional (3 D) attitude detected by the six-axis combined sensor dynamically.FindingsExperimental results indicate that the DLAAD algorithm is correct and effectively levels the drilling platform dynamically. It can thus provide essential support in resolving drill rod sticking problems during actual underground coal mine drilling operations.Practical implicationsThe DLAAD algorithm supports smooth drill rod operations in underground coal mines, which greatly enhances safety, reduces power consumption, and minimizes cost. The approach proposed here thus represents considerable benefits in terms of coal mine production and shows notable potential for application in similar fields.Originality/valueThe novel DLAAD algorithm and leveling control method are the key contributions of this work, they provide dynamical 3 D leveling and help to resolve drill rod sticking problems.

Photocontrollable Resistivity Change in Nanoparticle-Doped Liquid Crystal Alignment Layer: Voltage Holding and Discharging Properties of Fringe-Field Switching Liquid Crystal Modes

In liquid crystal (LC) displays, deriving an optimum resistance level of an LC alignment polyimide (PI) layer is important because of the trade-off between the voltage holding and surface-discharging properties. In particular, to apply a power-saving low-frequency operation scheme to fringe-field switching (FFS) LC modes with negative dielectric LC (n-LC), delicate material engineering is required to avoid surface-charge-dependent image flickering and sticking problems, which severely degrade with lowering operation frequency. Therefore, this paper proposes a photocontrolled variable-resistivity PI layer in order to systematically investigate the voltage holding and discharging properties of the FFS n-LC modes, according to the PI resistivity (ρ) levels. By doping fullerene into the high-ρ PI as the photoexcited charge-generating nanoparticles, the ρ levels of the PI were continuously controllable with a wide tunable range (0.95 × 1015 Ω∙cm to 5.36 × 1013 Ω∙cm) through Ar laser irradiation under the same LC and LC alignment conditions. The frequency-dependent voltage holding and discharge behaviors were analyzed with photocontrolled ρ variation. Thus, the proposed experimental scheme is a feasible approach in PI engineering for a power-saving low-frequency FFS n-LC mode without the image flickering and image sticking issues.

Application of High Pressure Water Jet Technology in Cleaning Polymerization Vessel

In recent years, the demand for organic synthetic materials in chemical production process is increasing, in order to meet the growing demand for organic synthetic materials in various fields. As the core equipment, the efficient and orderly operation of polymerizer is very important to ensure safe production and improve production efficiency. Under normal working conditions, the deposition or adhesion of polymer plasticizers will inevitably occur as long as there are monomer contacts in the polymerization reaction of any process, and the adhesion of polymer products to the wall of the reactor will cause sticking problems, so regular cleaning of the reactor has become a necessary link. High-pressure water jet cleaning technology is a new type of cleaning technology emerging in the world in recent years. It has the advantages of low cost, high speed, high cleaning rate, no damage to the cleaned products, no pollution, etc. In this paper, the concept of cleaning polymerizer with high pressure water jet technology is briefly introduced. Through the study of the mechanism of the autoclave and the analysis of the characteristics of the autoclave, the cleaning of polymerizer with high pressure water jet technology is discussed.

Set of measures to prevent liner sticking during directional drilling

The study considers the sticking problems of drilling. The study presents the classification and gives a general characteristic of liners. It is shown that the largest number of troubles occurs due to differential sticking. Differential sticking and methods of its elimination are considered in detail. The set of measures to prevent sticking, including the use of the Rhino XC Tool borehole expander, filters with plugs, dry lubrication, eccentric shoe, is developed and proposed.

Impact of surface roughness of pre-treated punches and powder properties on prevention of sticking during pharmaceutical tableting

In the present study, surface-modified punches with different roughness were evaluated for their ability to prevent sticking during pharmaceutical tableting using a single punch machine. The surface roughness of the punch faces was assessed using a laser microscope. Acetaminophen and ibuprofen were used as model active pharmaceutical ingredients (APIs) for the tableting tests. The amounts of API powders adhering to the punch faces after tableting were evaluated using spectrophotometric methods. Although the surfaces of the pre-treated punch faces were developed to prevent sticking during tableting, the sticking prevention was greater for acetaminophen than ibuprofen, and the sticking prevention was shown to depend on the mechanical properties of the API powders—namely, plasticity and elasticity. During continuous tableting the formulations, the surface-modified punches maintained their anti-sticking properties. We concluded that characterization of the sticking properties by the present methods using a single punch machine is useful (1) to select the most suitable type of punch face for tableting a drug formulation without a large loss of expensive APIs, and (2) to solve the sticking problems without changing the pharmaceutical formulations during manufacturing.

Broken Bricks and the Pick-up Sticks Problem

SummaryWe generalize the well-known broken stick problem in several ways, including a discrete “brick” analogue and a sequential “pick-up sticks/bricks” version. The limit behavior of the broken brick problem gives a combinatorial proof of the broken stick problem. The pick-up version gives a variation on those scenarios, and we conclude by showing a greater context—namely, that the broken stick/brick problem and the pick-up sticks/bricks problem are two extremes in a family of interesting, and largely open, questions.

New approach to optimizing risk management of the sticking problem using scale-independent critical material attributes and the quantitative process parameter.

In pharmaceutical manufacturing of solid formulations, blending with a lubricant is a key process in preventing sticking during compression. Sticking not only results in tablets with a disfigured appearance but also brings about the interruption of continuous operations. The aim of our study was to identify blending scale-independent critical material attributes (CMAs) in relation to the sticking problem to appropriately define the end-point of the blending process with magnesium stearate as lubricant. Results showed that the dispersive surface free energy (SFE) and the specific free energy absorptions (ΔGsp) of ethanol decreased during blending with magnesium stearate. As the two parameters decreased, the sticking problem was improved. In conclusion, we propose that the dispersive SFE and ΔGsp of ethanol are scale-independent CMAs, and that the minimum blending time (BTmin), which can be calculated from the two CMAs, of the quantitative process parameter show the minimum blending time required to achieve higher risk assessment of the sticking problem.