bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility Study on Enhanced Oil Recovery Using Fuzzy-Ball Fluid in Offshore Heterogeneous Sandstone Reservoir
Authors: Wang Chao , Zheng Lihui , Wei Panfeng , Yang Mingzheng , Zhang Wang , Wu Tong
Published: December 2020

The heterogeneity of reservoirs in offshore oilfields, which causes low utilization of low-permeability reservoirs and poor exploitation of crude oil, is usually serious. Till date, fuzzy-ball fluids have been used to improve oil recovery of terrestrial heterogeneous reservoirs, but it is still uncertain whether it could enhance the recovery of offshore oilfields, because of high cost and special operating environment in offshore oilfields. To this end, laboratory core flooding experiments and field tests were conducted. The results of the feasibility analysis show that: (1) Fuzzy-ball fluid has good injection and plugging performance, which means fuzzy-ball fluid has great potential to be applied in enhancing recovery. (2) Fuzzy-ball fluid can greatly improve oil recovery, especially the recovery of low-permeability cores. Compared with polymer, surfactant and microsphere, fuzzy-ball fluid led to 30% higher recovery of low-permeability cores. (3) The application of fuzzy-ball fluid in enhancing recovery has good economic feasibility. The input-output ratio of fuzzy-ball fluid is 1:4.3. It is concluded that the use of fuzzy-ball fluid in the heterogeneous sandstone reservoirs for enhanced oil recovery is feasible.
Estimating Loads From Breaking Waves Using Operational Modal Analysis
Authors: Vigsø Michael , Georgakis Christos
Published: December 2020

Load effects from breaking waves on offshore structures may be a driving point for the design. It is hence important to assess the likelihood of occurrence along the magnitude of the loads in the event of an impact. Traditionally, loads are predicted using wave theory combined with a load model such as the Morison. This paper features an alternative approach in determining the loads from wave breaking. It is demonstrated how the structural response can be used for (indirectly) estimating the magnitude of the loads caused by wave breaking. The theory is applied to an experimental setup in a wave flume, where a flexible model is subjected to loads from breaking waves. The dynamic properties are mapped using operational modal analysis and it is consequently shown that the loads can be identified using the vibration measurements.
Stationary Intervals for Random Waves by Functional Clustering of Spectral Densities
Authors: Rivera-García Diego , García-Escudero Luis Angel , Mayo-Iscar Agustín , Ortega Joaquin
Published: December 2020

A new time series clustering procedure, based on Functional Data Analysis techniques applied to spectral densities, is employed in this work for the detection of stationary intervals in random waves. Long records of wave data are divided into 30-minute or one-hour segments and the spectral density of each interval is estimated by one of the standard methods available. These spectra are regarded as the main characteristic of each 30-minute time series for clustering purposes. The spectra are considered as functional data and, after representation on a spline basis, they are clustered by a mixtures model method based on a truncated Karhunen-Loéve expansion as an approximation to the density function for functional data. The clustering method uses trimming techniques and restrictions on the scatter within groups to reduce the effect of outliers and to prevent the detection of spurious clusters. Simulation examples show that the procedure works well in the presence of noise and the restrictions on the scatter are effective in avoiding the detection of false clusters. Consecutive time intervals clustered together are considered as a single stationary segment of the time series. An application to real wave data is presented.
Impact of Forced Roll Motion on the Ice Resistance of Modern Icebreaking Bow Geometries
Authors: Daniel Johanna Marie , Romu Tuomas , von Bock und Polach R. U. Franz , Abdel-Maksoud Moustafa , Skogström Toni
Published: December 2020

Following the development of low friction hull coatings and azimuthing propulsion for icebreaking vessels, the development of auxiliary systems for reducing ice resistance fell from focus of research. One of these systems is comprised of active heeling tanks which induce a forced roll motion on the icebreaker. Today it is not fully understood how effective or even useful such systems would be for the icebreaking performance in combination with a modern icebreaking hull form. In this study, the impact of active heeling systems on level ice resistance is investigated by performing ice model tests with an icebreaker representing the latest design generation. The level ice thickness used in the model tests corresponds to the maximum continuous icebreaking capability of the evaluated vessel in multi-year ice conditions. Additionally, a calculation method is developed to predict the impact of forced roll motion on the ice resistance. The calculated prediction is evaluated against the model-scale data. Finally, the effectiveness of the active heeling system is evaluated from an engineering perspective: does the active heeling system reduce the power demand, or would the same result be achievable by increasing the propulsion power accordingly. It was found that the roll motion impacts the ice resistance in level ice. The main influence in this regard lies with the tank volume and metacentric height of the icebreaker. Additionally, it was observed that an optimum heel angle dependent on the ice condition can be determined which is not necessarily the highest one achievable. The case study predicts a reduced power demand for a modern icebreaker hull form in harsh ice conditions.
Optimization of the Trench Dimensions for Bahrain LNG Import Terminal Project
Authors: Seo Donghee , Kim Youngho , Hossain Muhammad Shazzad
Published: December 2020

Large deformation finite element analyses were carried out to investigate the optimized trench geometry for 24 inch (610 mm) diameter subsea pipelines and power cables (33 kV; outer diameter = 186 mm) used for transporting gas in shallow water depth (approximately 15 m), with an emphasis being on pipe-soil interaction assessment. An extensive parametric investigation was performed varying the relative density of the backfill sand (35%, 54% and 78%) and buried depth (1.89 and 3.14 diameters). Upward and lateral soil failure mec hanisms around a pipe uplifting in a backfill sand layer were compared. The failure mechanisms were manifested by shear band formation and subsequent propagation. It was shown that the trench dimensions originally designed based on conventional conservative approaches can be reduced by up to 10.6% in loose backfill sand (ID = 35%) and 8.7% in dense backfill sand (ID = 78%), leading to minimize cost and time of trenching and backfilling.
Coupled CFD and FEA to Predict the Dynamic Structural Response of Modern Cruise Ship Deck Outfitting due to Wind-Induced Vibrations
Authors: Kivelä Eetu , Lakshmynarayanana P. A. , Hirdaris Spyros
Published: December 2020

Recent market trends in the cruise industry aim to provide land-based attractions on mega-cruise liners deck amusements. The structures used are mega-lightweight structures that comprise of slender beams to reduce added weight. They may be subject to dynamic wind-induced resonance as a result of fluctuating forces due to vortex shedding occurring close to the natural frequency of the structure. This paper investigates the structural responses due to wind-induced vibrations in the context of a ship deck outfitting by coupling CFD and FEA. The simulations are performed using one- and two-way coupling FSI to gain insights into the differences between the predicted responses. A deck amusement structure is idealized as an aluminum portal frame subjected to a constant head wind. Transient one- and two-way coupled simulations, based on Reynolds-Averaged Naiver-Stokes (RANS) and linear elastic 3D FEA are conducted. The predictions are compared against quasi-dynamic beam element idealizations.
Vibratory Installation Study of a Monopile in Dense Sand
Authors: Holeyman Alain , Whenham Valérie , Peralta Proserpine , Ballard Jean-Christophe , Chenicheri Pulukul Sunil
Published: December 2020

The assessment of monopile installation by means vibratory driving is discussed for a platform located in the Dutch Sector of the North Sea. The vibratory driving analysis of the 4.7 m diameter monopile was performed using the “Hypervib” method in order to evaluate the performance of a 960 kg.m excentric moment vibrohammer. The results of the installation study indicated that the monopile could be installed up to a penetration depth of 31.5 m considering the full nominal power and frequency (23 Hz) of the specified vibrohammer.

The frequency of the vibrator is shown to influence the projected penetration of the monopile. In particular, the “Hypervib” method indicated that refusal could be encountered if the effective frequency of the vibrator dropped below 20 Hz. As a consequence, monitoring measures were recommended to mitigate/characterize the risks of early refusal.
Reduction in Mooring System Lifetime due to Corrosion and Severe Storms
Authors: MacNicoll Michael , Akers Richard , Sharman Krish Thiagarajan , Hsu Wei-Ting
Published: December 2020

We report on a multi-year investigation into mechanisms of fatigue, corrosion, and abrasion on floating offshore wind turbine (FOWT) mooring systems funded by the U.S. Bureau of Safety and Environmental Enforcement (BSEE). The project team examined the efficacy of standards-based design procedures as they relate to fatigue damage and material degradation.

Best practice design encourages applying 50% of a mooring chain corrosion allowance to fatigue calculation. However, the project team concludes that this practice may underestimate fatigue damage when the corrosion rate is high relative to the component diameter. A more robust accounting of corrosion rate in fatigue calculations decreased the predicted lifetime of a mooring system by over 80% in one small scale field deployed case study. This discrepancy was reduced in a similar comparison of a full-scale system.

Best practice design focuses on operational and normal sea states for fatigue damage calculation. The project team has concluded, through simulation of validated case studies, that severe storms may contribute significant fatigue damage to chain moorings. Over 50% of the fatigue on a prototype FOWT mooring was caused by storms which occur less than 0.2% of the time. A single 20-year storm produced over 15% of the anchor fatigue of a theoretical full-scale FOWT.

By augmenting standards-based predictions of the degradation rate of chain-based mooring systems through better accounting for corrosion and abrasion rates over the full lifetime of the mooring system and including rare, extreme storms in fatigue calculations, the engineer or developer can plan ahead and reduce the risk of dangerous and expensive failures.
Numerical Studies on Dynamic Behavior of Tubular Pipes Under Repeated Impacts
Authors: Zhu Ling , Wang Xiangui , Guo Kailing , Ma Bin
Published: December 2020

The tubular pipes of Jacket platform may be frequently subjected to repeated impact loadings from vessels and dropped objects during the operation life, which may lead to serious damages to the platform. In this paper, the numerical studies on dynamic behavior of tubular pipe subjected to repeated impact loadings was performed. The deformation profile and permanent deflection in numerical simulation were compared with those in experiment, and good agreement was achieved. Besides, the mechanism of deformation accumulation and energy absorption were analyzed. Results showed that, the tubular pipe mainly produced transverse expanding and local dent, the global bending was very small. The permanent deflection at the middle of the pipe increased as the impact numbers increased, while the increment decreased. In addition, with the increase of impact number, the elastic deformation energy stored by the tubular pipe increased, and the plastic deformation energy decreased.
Additive Manufacturing in the Oil and Gas Industry Overview
Authors: De Bernardi Carlo
Published: December 2020

The API 20S Standard is designed to play a crucial role in leveraging Additive Manufacturing (AM) to foster innovation in the oil and gas industry. The paper, in association with the standard, will facilitate the understanding of how AM will enable equipment design improvements, faster prototyping, and better inventory management. By way of discussing the progress, challenges, and lessons learned from the standardization process, the paper aims to encourage a safer, broader, and faster adoption of AM technologies in the mainstream oil and gas applications.

The paper will summarize the streamlining process, feedback from the API 20S task group, and current status of the standardization efforts. Additionally, upcoming challenges and the potential for the oil and gas industry industries to contribute to the standard will be summarized. The paper will also showcase a novel tiered approach (Additive Manufacturing Specification Levels) to allow the users of the document to match different levels of criticality.
Drilling Cutting Analysis to Assist Drilling Performance Evaluation in Hard Rock Hole Widening Operation
Authors: Ahmed Daiyan , Xiao Yingjian , de Moura Jeronimo , Butt Stephen D.
Published: December 2020

Optimum production from vein-type deposits requires the Narrow Vein Mining (NVM) process where excavation is accomplished by drilling larger diameter holes. To drill into the veins to successfully extract the ore deposits, a conventional rotary drilling rig is mounted on the ground. These operations are generally conducted by drilling a pilot hole in a narrow vein followed by a hole widening operation. Initially, a pilot hole is drilled for exploration purposes, to guide the larger diameter hole and to control the trajectory, and the next step in the excavation is progressed by hole widening operation. Drilling cutting properties, such as particle size distribution, volume, and shape may expose a significant drilling problem or may provide justification for performance enhancement decisions. In this study, a laboratory hole widening drilling process performance was evaluated by drilling cutting analysis. Drill-off Tests (DOT) were conducted in the Drilling Technology Laboratory (DTL) by dint of a Small Drilling Simulator (SDS) to generate the drilling parameters and to collect the cuttings. Different drilling operations were assessed based on Rate of Penetration (ROP), Weight on Bit (WOB), Rotation per Minute (RPM), Mechanical Specific Energy (MSE) and Drilling Efficiency (DE). A conducive schedule for achieving the objectives was developed, in addition to cuttings for further interpretation. A comprehensive study for the hole widening operation was conducted by involving intensive drilling cutting analysis, drilling parameters, and drilling performance leading to recommendations for full-scale drilling operations.
Tubular Connection Assembly for Improved Fatigue Performance of Metallic Risers
Authors: Mansour Ghiath (Guy)
Published: December 2020

Fatigue is a primary challenge in the design of steel catenary risers (SCRs) and different measures and methods are utilized to mitigate it. Traditional upset ends and steel lazy wave risers (SLWRs) are such methods to mitigate fatigue.

SLWRs were first used in 2009 on the Espirito Santo floating, production, storage, and offloading (FPSO) vessel of Shell Company’s Parque das Conchas (BC-10) project offshore Brazil. SLWRs have been used increasingly since then and gained popularity especially in recent years.

A novel patented tubular connection assembly is presented herein which improves the fatigue life of SCRs and welded connections in general.

This novel tubular connection assembly has many advantages. It overcomes the thickness limitation of welding traditional upset ends and reduces offshore welding time, cost, and risk.

When used in simple SCRs, this novel tubular connection assembly renders simple SCRs an alternative robustly viable at significantly lower cost, shorter schedule, and many additional advantages as compared to SLWRs. Of such many advantages, simple SCRs are simpler to configure, analyze, design, and install using wider installation methods and vessels. They also use less material and offer better short- and long-term integrity especially for insulated SCRs. In addition, they have smaller footprint and are less prone to clashing.
Quantitative Characterization, Design Considerations and Sustainable Resource Management for Middle Eastern Tight Gas Reservoirs
Authors: Suboyin Abhijith , Motiur Rahman Md , Haroun Mohamed
Published: December 2020

Augmented by recent activities in the oil and gas industry, it can be seen that an economical and efficient hydraulic fracturing job has become critical for the successful development of unconventional reservoirs. However, exploitation of unconventional reservoirs is heavily water-intensive as compared to conventional reservoirs. Given this concern, it is essential to reform how water is managed within the industry, especially in water scarce regions such as the Middle East.

In this study, a comprehensive investigation that deals with the quantification of changes with respect to variation in prime contributors within a traditional fracture design process is presented. This can assist to determine the distinct contributions of an element within fracture design parameters, as they are imperative to evaluate the nature of fracture propagation. After an extensive assessment, a set of natural fractures were introduced to the system and the system behavior was further investigated to identify their behavior and optimize resource management. Based on an iterative process, the results of the constructed simulation models were analyzed in depth and validated with field data.

Overall, the results indicate that for the given field conditions, fluid and proppant optimization are critical to achieve maximum recovery. The dominance of parameters such as fracture width, fracture length, proppant placement and Young’s Modulus are also illustrated in depth. To examine the associated response on long-term productivity, the results have been extended to current field practices and cases. A rough analysis was conducted in-house, on geological data from a candidate field in the Middle East. Findings shows the potential to optimize and reduce the required water for an operation by 1.3 million gallons. This further highlights the need to optimize and tailor an adaptable workflow, which is proposed in this study, for water scarce regions such as the Middle East.

In addition to ultimately assisting in verification of modern best practices, this investigative approach will create a paradigm for future studies within the Middle Eastern region to assist in a simplistic prediction of fracture propagation behavior and its associated response to optimize water usage. The results have also been extended along with comparisons to current field practices.
Study on Formation and Dissociation of Methane Hydrate in Sandstone Using Low-Field Nuclear Magnetic Resonance Technology
Authors: Ji Yunkai , Hou Jian , Liu Yongge , Du Qingjun
Published: December 2020

Natural gas hydrate, as an unconventional resource, has been attracting increasing attention. Understanding the characteristics of methane hydrate formation and dissociation in porous media is important for developing gas hydrate-bearing reservoirs. This work discusses the use of low-field nuclear magnetic resonance (LF-NMR) technology to investigate the formation and dissociation of methane hydrate in the sandstone.

In this work, an experimental assembly wherein methane hydrate can form and dissociate, is used to conduct LF-NMR measurements. LF-NMR, as a noninvasive measurement technology, combines the transverse relaxation time (T2) measurement with the magnetic resonance imaging (MRI). T2 measurements can explore the characteristics of methane hydrate formation and dissociation in core samples from a pore-scale perspective. MRI can display the spatial distribution of water from a core-scale perspective. The excess-gas method and the excess-water method are successively applied to form methane hydrate, and depressurization is applied to dissociate methane hydrate in the laboratory. The characteristics of methane hydrate formation and dissociation is studied in the sandstone.

Experimental results show that the signal intensity of short T2 and long T2 decreases simultaneously in the process of the methane hydrate formation using the excess-gas method, indicating that methane hydrate is formed in both small and large pores. When using the excess-water method, the signal intensity of long T2 decreases, and the signal intensity of short T2 increases in the process of the methane hydrate formation, indicating that methane hydrate is mainly formed in large pores. Methane hydrate is dissociated simultaneously in both small and large pores when using the depressurization method. Water content in small pores gradually increases. Capillary pressure causes some water to remain in the core samples following dissociation. Water content in large pores decreases initially and then increases during depressurization. In the early stages of depressurization, more water leaves large pores than is generated by hydrate dissociation. In the later stages of depressurization, less water leaves the large pores than is generated by hydrate dissociation.

This study may inspire the new understanding on distribution of fluid in sediments during the process of accumulation and exploitation of natural gas hydrates.
Influence of Soil’s Vertical Stiffness on Estimation of Fatigue Life for Steel Catenary Risers (SCRs)
Authors: Cao Jianchun , Chen Xingnian , Cheng Jingyun , Cao Peimin
Published: December 2020

Fatigue damage estimation is a key part in a Steel Catenary Riser (SCR) system design. The riser-soil interaction has a significant influence on the fatigue assessment for a SCR system at the Touch-Down Zone (TDZ) because the soil’s vertical stiffness is a critical parameter. The conventional methods developed to calculate the soil’s vertical stiffness, for example, DNV method [10], Bridge method [4] and Audibert method [3], were based on the assumption that at the TDZ area the soil mass being interacted by the pipe is always under intact condition. Recently, Chen et al. published a newly developed method [5, 6], which was based on the laboratory test results carried out by Texas A&M University in the late 1980s and was further verified by recent laboratory displacement-controlled tests by Texas A&M University [2], resulting in softer soil’s vertical stiffness. In order to understand the difference between Chen method and the conventional methods as well as the influence of Chen method on the SCR design, a study was carried out for a given soil condition and three typical sizes of riser pipes and is documented in this paper. In this paper, firstly, various methods used to calculate soil’s vertical stiffness, i.e., DNV method, Bridge method, Audibert method, and Chen method, were briefly introduced. Secondly, a discussion was performed on the model of the conventional methods and the model of Chen method. Thirdly, as an example for a given soil condition, the soil’s vertical stiffness was estimated using these methods respectively for 6″-dia., 12″-dia., and 18″-dia. riser pipes. Finally, the fatigue damages for various riser pipes were computed using the estimated soil’s vertical stiffness and a comparison on the estimated fatigue damages was performed. The study results showed that the soil’s vertical stiffness estimated by Chen method was about one order magnitude weaker than these estimated by the conventional methods. In other words, the soil’s vertical stiffness estimated by the conventional methods was about 5 to 11 times that estimated by Chen method. The pipe’s fatigue life estimated using the soil’s vertical stiffness of Chen method was about 1.5 times (i.e., 50% longer than) that estimated using the soil’s vertical stiffness of the conventional methods. These study results could improve a SCRs designer’s understanding on: 1) the difference between the model of the conventional methods and the model of Chen method, 2) the impact of Chen method on the estimated fatigue life, and 3) that as the model of the conventional methods is a closer representative of the prototype and their results are more conservative, it is recommended to use the conventional methods for SCRs design. Eventually, these will help the designers to select an appropriate method for calculating the soil’s vertical stiffness in the SCRs design.
n-Regular functions in quaternionic analysis
Authors: Frenkel Igor , Libine Matvei
Published: December 2020

In this paper, we study left and right [Formula: see text]-regular functions that originally were introduced in [I. Frenkel and M. Libine, Quaternionic analysis, representation theory and physics II, accepted in Adv. Theor. Math. Phys]. When [Formula: see text], these functions are the usual quaternionic left and right regular functions. We show that [Formula: see text]-regular functions satisfy most of the properties of the usual regular functions, including the conformal invariance under the fractional linear transformations by the conformal group and the Cauchy–Fueter type reproducing formulas. Arguably, these Cauchy–Fueter type reproducing formulas for [Formula: see text]-regular functions are quaternionic analogues of Cauchy’s integral formula for the [Formula: see text]th-order pole [Formula: see text] We also find two expansions of the Cauchy–Fueter kernel for [Formula: see text]-regular functions in terms of certain basis functions, we give an analogue of Laurent series expansion for [Formula: see text]-regular functions, we construct an invariant pairing between left and right [Formula: see text]-regular functions and we describe the irreducible representations associated to the spaces of left and right [Formula: see text]-regular functions of the conformal group and its Lie algebra.
(𝔤,K)-module of O(p,q) associated with the finite-dimensional representation of 𝔰𝔩2
Authors: Hashimoto Takashi
Published: December 2020

The main aim of this paper is to show that one can construct [Formula: see text]-modules of [Formula: see text] associated with the finite-dimensional representation of [Formula: see text] by quantizing the moment map on the symplectic vector space [Formula: see text] and using the fact that [Formula: see text] is a dual pair. Then one obtains the [Formula: see text]-type formula, the Gelfand–Kirillov dimension and the Bernstein degree of them for all non-negative integers [Formula: see text] satisfying [Formula: see text] when [Formula: see text] and [Formula: see text] is even. In fact, one finds that the Gelfand–Kirillov dimension is equal to [Formula: see text] and the Bernstein degree is equal to [Formula: see text].
Hydrogenation as a source of superconductivity in two-dimensional TiB2
Authors: Wang Hui , Pan Chen , Wang Sheng-Yan , Jiang Hong , Zhao Yin-Chang , Su Yue-Hua , Zhong Guo-Hua , Zhang Chao
Published: December 2020

Using first-principles calculations based on density functional perturbation theory, we demonstrate hydrogenation-induced superconductivity in monolayer TiB2H. Hydrogen adatoms destroy the Dirac state of monolayer TiB2 and monolayer TiB2H has a high vibration frequency. Monolayer TiB2H is a phonon-mediated superconductor. Monolayer TiB2H has a predicted [Formula: see text] of 8[Formula: see text]K, which further increases under external tensile strain. Thus, this study extends our understanding of superconductivity in two-dimensional (2D) materials and its potential applications.
Implementation of the ATLAS-SUSY-2019-08 analysis in the MadAnalysis 5 framework (electroweakinos with a Higgs decay into a bb̄ pair, one lepton and missing transverse energy; 139 fb−1)
Authors: Goodsell Mark D.
Published: December 2020

This is the validation note for the recast in MadAnalysis 5 of the study ATLAS-SUSY-2019-08: a search for direct production of electroweakinos in final states with one lepton, missing transverse momentum and a Higgs boson decaying into two [Formula: see text]-jets in [Formula: see text] collisions at [Formula: see text] = 13 TeV with the ATLAS detector, using an integrated luminosity of 139 fb[Formula: see text]. The recasting code is validated against cutflows and expected signal events for benchmark scenarios, and the exclusion limits are reproduced for a simplified supersymmetric electroweakino sector consisting of a degenerate wino decaying to a light stable bino.
Lorentz invariance violation and modified Hawking fermions tunneling radiation of stationary axially symmetric black holes
Authors: Luo Z. , Nie W. F. , Feng Y. Y. , Lan X. G.
Published: December 2020

Based on a higher energy scale, the dispersion relation might be corrected. Correspondingly, the Hamilton–Jacobi equation should also be modified. In this paper, we use the correction to study the fermion tunneling radiation for a Gibbons–Maeda–Garfinkle-Horowitz–Strominger (GMGHS) black hole, a Kerr–NUT black hole, and an Einstein–Maxwell–Dilaton–Axion (EMDA) black hole. The result shows that compared to the charged GMGHS black hole and the rotating Kerr–NUT black hole, the Hawking temperate and the entropy of the rotating charged EMDA black hole not only are related to the correction parameter [Formula: see text] and particle mass [Formula: see text] but also depend on the angle parameter [Formula: see text] of the black hole coordinates.
Kink–antikink scattering-induced breathing bound states and oscillons in a parametrized ϕ4 model
Authors: Nzoupe F. Naha , Dikandé Alain M. , Tchawoua C.
Published: December 2020

Recent studies have emphasized the important role that a shape deformability of scalar-field models pertaining to the same class with the standard [Formula: see text] field, can play in controlling the production of a specific type of breathing bound states so-called oscillons. In the context of cosmology, the built-in mechanism of oscillons suggests that they can affect the standard picture of scalar ultra-light dark matter. In this paper, kink scatterings are investigated in a parametrized model of bistable system admitting the classical [Formula: see text] field as an asymptotic limit, with focus on the formation of long-lived low-amplitude almost harmonic oscillations of the scalar field around a vacuum. The parametrized model is characterized by a double-well potential with a shape-deformation parameter that changes only the steepness of the potential walls, and hence the flatness of the hump of the potential barrier, leaving unaffected the two degenerate minima and the barrier height. It is found that the variation of the deformability parameter promotes several additional vibrational modes in the kink-phonon scattering potential, leading to suppression of the two-bounce windows in kink–antikink scatterings and the production of oscillons. Numerical results suggest that the anharmonicity of the potential barrier, characterized by a flat barrier hump, is the main determinant factor for the production of oscillons in double-well systems.
Heavy flavor jets in ALICE
Authors: Artem Isakov
Published: December 2020

Heavy-flavor quarks are considered to be effective probes of the Quark–Gluon Plasma (QGP) produced in ultra-relativistic heavy-ion collisions. Since quarks have a large mass, their production takes place mostly in initial hard processes, and it is calculable using perturbative QCD. Thus, heavy flavor quarks can be considered as ideal early-generated penetrating probes of the created medium and utilized to investigate mass-dependent properties of in-medium parton energy loss. Moreover, the measurement of heavy-flavor jet production in pp, besides being a natural reference for Pb–Pb studies, allows testing pQCD calculations and models of charm fragmentation in vacuum. In addition, similar measurements in p–Pb collisions allow assessing the importance of cold nuclear matter effects. The ALICE experiment at the LHC has excellent particle tracking capabilities, that allow for a precise jet reconstruction and for the identification of [Formula: see text]-meson and beauty hadron decay vertices, displaced hundreds of micrometers from the primary interaction vertex. In this proceedings, we will report the latest heavy-flavor jet measurements performed in p–Pb and pp collisions.
Models for functor categories over self-injective quivers
Authors: Zhu Rongmin , Zhang Houjun
Published: December 2020

Let [Formula: see text] be a ring, [Formula: see text] a small [Formula: see text]-preadditive category, and let [Formula: see text] be the category of [Formula: see text]-linear functors from [Formula: see text] to the left [Formula: see text]-module category [Formula: see text]. Given a cotorsion pair [Formula: see text] in [Formula: see text], we construct four cotorsion pairs [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] in [Formula: see text] and investigate when these cotorsion pairs are hereditary and complete. Moreover, under few assumptions, we show that there exist a recollement of homotopy categories induced by these cotorsion pairs. Finally, some applications are given in the category of [Formula: see text]-periodic chain complexes of [Formula: see text]-modules.
The Beginning of the Nuclear Age
Authors: Shifman M.
Published: December 2020

The birth of nuclear physics in the 1920s and its culmination in the 1940s which changed human history forever is reviewed in broad touches. I briefly mention further developments of nuclear physics connecting it to modern astrophysics, high-energy physics, etc.
Rolling Railgun: A Lab Activity for Introductory Electromagnetism
Authors: Overduin James , Pettaway Taylor , Clark Hannah , Edmonston Mark
Published: December 2020

We describe a laboratory exercise for an introductory calculus-based electricity and magnetism course in which students construct and study the performance of a “rolling railgun” formed by two small coin magnets connected by a ferromagnetic axle which carries current from one rail to the other. This exercise can be scaled up from a simple, mostly qualitative activity to a more comprehensive comparison between theory and experiment that will challenge students’ calculus skills. The required components are small and inexpensive enough to mail to students who are taking the course remotely. We report on our initial success in incorporating this lab into our curriculum at Towson University.
New Insights in Muscle Biology that Alter Meat Quality
Authors: Matarneh Sulaiman K. , Silva Saulo L. , Gerrard David E.
Published: December 2020

Fresh meat quality is greatly determined through biochemical changes occurring in the muscle during its conversion to meat. These changes are key to imparting a unique set of characteristics on fresh meat, including its appearance, ability to retain moisture, and texture. Skeletal muscle is an extremely heterogeneous tissue composed of different types of fibers that have distinct contractile and metabolic properties. Fiber type composition determines the overall biochemical and functional properties of the muscle tissue and, subsequently, its quality as fresh meat. Therefore, changing muscle fiber profile in living animals through genetic selection or environmental factors has the potential to modulate fresh meat quality. We provide an overview of the biochemical processes responsible for the development of meat quality attributes and an overall understanding of the strong relationship between muscle fiber profile and meat quality in different meat species.
Communication—Application of the Adsorptive Stripping Voltammetry to the Determination of Ti(IV) Content in Extracts of Stinging Nettle Leaves
Authors: Adamczyk Marzena , Grabarczyk Małgorzata
Published: December 2020

Stinging nettle is a perennial plant from the Urticaceae botanical family. Apart from various biologically active compounds with health-promoting properties, it contains large amounts of titanium, which plays a key role in growing plants. This work focuses on the determination of titanium content in leaves of stinging nettle by adsorptive stripping voltammetry. For this purpose, dry leaves of stinging nettle from three different producers were used to obtain extracts using high pressure microwave-assisted mineralization. The obtained results confirm the satisfactory accuracy of the developed voltammetric procedure and its usefulness for determining this kind of real samples.
Astragalus membranaceus Injection Protects Retinal Ganglion Cells by Regulating the Nerve Growth Factor Signaling Pathway in Experimental Rat Traumatic Optic Neuropathy
Authors: Wu Qiong , Gu Xinyi , Liu Xinyan , Yan Xiaoling , Liao Liang , Zhou Jian
Published: December 2020

Activation of the nerve growth factor (NGF) signaling pathway is a potential method of treatment for retinal ganglion cell (RGC) loss due to traumatic optic neuropathy (TON). The present study aimed to explore the biological effects of injecting Astragalus membranaceus (A. mem) on RGCs in an experimental TON model. Adult male Wistar rats were randomly divided into three groups: sham‐operated (SL), model (ML), and A. mem injection (AL). The left eyes of the rats were considered the experimental eyes, and the right eyes served as the controls. AL rats received daily intraperitoneal injections of A. mem (3 mL/kg), whereas ML and SL rats were administered the same volume of normal saline. The TON rat model was induced by optic nerve (ON) transverse quantitative traction. After two‐week administration, the number of RGCs was determined using retrograde labeling with Fluoro‐Gold. The protein levels of NGF, tyrosine kinase receptor A (TrkA), c‐Jun N‐terminal protein kinase (JNK), JNK phosphorylation (p‐JNK), and nuclear factor kappa‐B (NF‐κB) were assessed using western blotting. The levels of p75 neurotrophin receptor (p75NTR) and NF‐κB DNA binding were examined using real‐time PCR and an electrophoretic mobility shift assay. In addition, the concentrations of JNK and p‐JNK were assessed using an enzyme‐linked immunosorbent assay. Results. The number of RGCs in ML was found to be significantly decreased (P < 0.01) relative to both AL and SL, together with the downregulation of NGF (P < 0.01), TrkA (P < 0.05), and NF‐κB (P < 0.01); upregulation of p75NTR mRNA (P < 0.01); and increased protein levels of JNK (P < 0.05) and p‐JNK (P < 0.05). Treatment using A. mem injection significantly preserved the density of RGCs in rats with experimental TON and markedly upregulated the proteins of NGF (P < 0.01), TrkA (P < 0.05), and NF‐κB (P < 0.01) and downregulated the mRNA level of p75NTR(P < 0.01), as well as the proteins of JNK (P < 0.05) and p‐JNK (P < 0.01). Thus, A. mem injection could reduce RGC death in TON induced by ON transverse quantitative traction by stimulating the NGF signaling pathway.
The New Mittag-Leffler Function and Its Applications
Authors: Ayub U. , Mubeen S. , Abdeljawad T. , Rahman G. , Nisar Kottakkaran Sooppy
Published: December 2020

In this paper, we investigate some properties of the Pochhammer

p
,
s
,
k

-symbol

ξ

n
,
k
,
s

p

and gamma

p
,
s
,
k

-function

Γ

s
,
k

p

ξ

. We then prove several identities for newly defined symbol

ξ

n
,
k
,
s

p

and the function

Γ

s
,
k

p

ξ

. The integral representations for the gamma

p
,
s
,
k

-function and beta

p
,
s
,
k

-function are presented. Also, we define a new Mittag-Leffler

p
,
s
,
k

-function and study its analytic properties and its transforms.
Effects of Clinicopathological Characteristics on the Survival of Patients Treated with PD-1/PD-L1 Inhibitor Monotherapy or Combination Therapy for Advanced Cancer: A Systemic Review and Meta-Analysis
Authors: Wei Yuhan , Li Yongfu , Du Qi , Peng Xinyi , Jin Jiangtao , Guo Hong , Li Yongyan , Li Qin
Published: December 2020

Background. PD-1/PD-L1 inhibitors have made unprecedented progress in the treatment of cancer. Methods. A systemic search was conducted for randomized controlled trials that compared PD-1/PD-L1 inhibitor monotherapy or combination therapy with nonimmunotherapy. Hazard ratios (HRs) of overall survival (OS) according to the sex, age, ECOG PS, smoking status, liver metastasis, PD-L1 expression, EGFR, and KRAS status of patients were analyzed. Results. Totally, 13 studies with monotherapy and 5 with combination regimens were included, and the pooled HRs of OS were 0.74 (

P
<
0.001

) and 0.64 (

P
<
0.001

), respectively. EGFR wild-type patients could benefit from immunotherapy monotherapy (HR, 0.77;

P
<
0.001

) while those of the mutant type had no survival benefit (HR, 1.11;

P
=
0.54

), and the difference was statistically significant (interaction,

P
=
0.005

). KRAS wild-type patients had no survival benefit from monotherapy (HR, 0.89;

P
=
0.49

). For combination therapy, both male and female derived benefits but female had a significantly reduced risk of death (HR, 0.45;

P
<
0.001

) compared with male (HR, 0.73;

P
<
0.001

; interaction,

P
=
0.004

). Nonsmokers derived more survival benefits from combination therapy (HR, 0.29;

P
<
0.001

) than smokers (HR, 0.63;

P
=
0.001

; interaction,

P
=
0.02

). No significant difference was found between age, ECOG PS, liver metastasis, PD-L1 expression, and OS of both PD-1/PD-L1 inhibitor monotherapy and combination therapy. Conclusions. Both PD-1/PD-L1 inhibitor monotherapy and combination therapy significantly prolonged the OS of patients with advanced malignant tumors. EGFR status for monotherapy and sex and smoking status for combination therapy were important predictors of survival benefits.
The Analysis of How Apnea Influences the Autonomic Nervous System Using Short-Term Heart Rate Variability Indices
Authors: He Baolin , Li Wenyu , Zhang Xiaotong , Wu Yanan , Liu Jing , Brewer Lara M. , Yu Lu
Published: December 2020

Objective. Frequent cessations of respiration can greatly increase the prevalence rate of arrhythmia. It has been confirmed that cardiac modulation is regulated by the autonomic nervous system (ANS). And heart rate variability (HRV) is widely used as a method to evaluate the function of the ANS. Therefore, we analyzed whether apnea can affect the balance and normal function of the ANS using short-term HRV indices. Methods. Forty-five healthy subjects were asked to breathe normally and hold their breathing to simulate 10 times apnea. Thirty-six patients from the dataset of a sleep laboratory for the diagnosis of sleep disorders with 10 times apnea were included in analysis. We calculated short-term HRV indices of subjects in normal respiratory and apneic states, respectively. Results. Compared with the normal respiratory state, respiration cease would lead to the values of Mean-RR, nLF, LF/HF, and α1 which significantly increased, whereas the values of rMSSD and nHF significantly decreased. Conclusions. Cessations of respiration would lead to an imbalance in the function of the ANS, as well as an increase in fractal characteristics of the heart. These changes in the physiological state are likely to induce and cause the occurrence of arrhythmia, which is regulated by the ANS.
Characteristics and Dynamics of Full Arch Distalization Using Transpalatal Arches with Midpalatal and Interradicular Miniscrews as Temporary Anchorage Devices: A Preliminary Finite Element Analysis
Authors: Khanehmasjedi Mashallah , Bagheri Sepideh , Rakhshan Vahid , Hasani Mojtaba
Published: December 2020

Introduction. Miniscrews have proved quite effective in fixed orthodontic treatment. They can be placed in areas like palatal interradicular zones or midpalatal suture. Despite the value of these methods and their ever-increasing use, their characteristics are not assessed before when implanted in palatal interradicular areas or in the midpalatal suture. We aimed to assess, for the first time, the dynamics of full arch distalization using such miniscrews. Methods. A 3D model of maxilla with all permanent dentition was created from a CT scan volume. Tissues were segmented and differentiated. Afterward, miniscrews and appliances were designed, and the whole model was registered within a finite element analysis software by assigning proper mechanical properties to tissues and orthodontic appliances. The full arches were distalized using transpalatal arches with miniscrews as anchorage devices (in two different models). The extents of stresses and patterns of movements of various elements (teeth, miniscrews, appliances, tissues) were estimated. Results and Conclusions. Comparing the two models, it is obvious that in both models, the stress distribution is the highest in the TPA arms and the head of the miniscrew where the spring is connected. In comparison with the displacement in the X-axis, the “mesial in” rotation is seen in the first molar of both models. But there is one exception and that is the “mesial out” rotation of the right second molar. In all measurements, the amount of movement in Model 2 (with palatal interradicular miniscrews) is more than that in Model 1 (with midpalatal miniscrew). In the Y-axis, more tipping is seen in Model 2, especially the anterior teeth (detorque) and the first molar, but in Model 1, bodily movement of the first molar is more evident. Along the Z-axis, the mesial intrusion of the first molar and the distal extrusion of this tooth can be seen in both models. Again, the displacement values are higher in the second model (with interradicular miniscrews). In comparison with micromotion and stress distribution of miniscrews, in Model 1, maximum stress and micromotion is observed at the head of the miniscrew where it is attached to the spring. Of course, this amount of micromotion increases over time. The same is true for Model 2, but with a lower micromotion. As for the amount of stress, the stress distribution in both miniscrews of both models is almost uniform and rather severe.
Treatment of Recurrent Primary Cutaneous Mucinous Carcinoma of the Eyelid with Modified Wide Local Excision
Authors: Tillit Stephanie M. , Iyer Siva S. R. , Grieser Eric J. , LiVecchi John T.
Published: December 2020

Primary cutaneous mucinous carcinoma (PCMC) is a rare, low-grade malignant neoplasm of the sweat gland, whose history has been controversial regarding eccrine versus apocrine origin. This case report describes a 53-year-old male who presented to the University of Florida, Gainesville, ophthalmology clinic and was referred to the oculoplastics service with a painless, subcentimeter mass on the lateral right upper eyelid including the canthus, consistent with recurrent primary cutaneous mucinous carcinoma of the eyelid. Four years prior, the patient had undergone excisional biopsy of the lesion in a clinic, which revealed residual tumor, but the patient deferred further surgery at the time. The patient underwent surgical excision of the mass with reconstruction without operative complications and with negative surgical margins. PCMC is difficult to diagnose clinically due to its rarity and requires a histopathological examination for confirmation of the diagnosis. This report presents the first case in the literature of primary cutaneous mucinous carcinoma in a patient with human immunodeficiency virus (HIV). With this case report, we aim to raise awareness of primary cutaneous mucinous carcinoma as a potential part of the differential diagnosis for malignant eyelid lesions, including those present in patients with HIV.