bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment on Strain-Based and Stress-Based Design Strategies for Components at Elevated Temperatures: A Comparative Study
Authors: Niu Tian-Ye , Gong Cheng , Gong Jian-Guo , Xuan Fu-Zhen , Chen Haofeng
Published: February 2020

Geometrical discontinuities (such as holes and grooves) widely exist in many components, which operate at elevated temperatures. Creep assessment of the geometrical discontinuities is essential for the safe operation of the system. In general, creep evaluations are conducted from the stress-based and strain-based strategies, but comparative studies on the extent of conservatism of these two design strategies are rarely included. In this work, creep test data of the notched components made of 9–12% Cr steel conducted by authors and that of 9Cr–1Mo steel collected from published works are employed for comparative evaluations. Results indicate that strain-based and stress-based strategies are both relatively conservative for notches in metal materials, and the conservatism of the assessment strategies increases with the notch acuity ratio of the component. The differences of the conservatism for strain-based and stress-based strategies are dependent on the notch acuity ratio and the ductility of the materials. For a blunt notch, the strain-based strategy is more conservative than the stress-based strategy for materials mentioned, while the dominant assessment strategy is dependent on stress redistribution performances of components with a sharp notch.
Evaluation of Stress Rupture Factors for Grade 91 Weldments
Authors: Kimura Kazuhiro , Yaguchi Masatsugu
Published: February 2020

Stress rupture factors and weld strength reduction factors for Grade 91 steel weldments in the codes and literatures have been reviewed. Stress rupture factors for weld metals proposed for code case N-47 in the mid 1980's was defined as a ratio of average rupture strength of the deposited filler metal to the average rupture strength of the base metal. Remarkable drop in creep rupture strength of weldments is significant issue of Grade 91, especially in the low-stress and long-term regime. A premature failure of Grade 91 steel weldments in the long-term, however, is caused by type IV failure which takes place in the fine grain heat affected zone (FG-HAZ), rather than fracture in the deposited weld metal. The stress rupture factor of the Grade 91 steel, therefore, was based on the creep rupture strength of cross weld test specimens. Creep rupture data of Grade 91 steel weldments reported in the publication of ASME STP-PT-077 were integrated with the creep rupture data collected in Japan and used for this study. Time- and temperature-dependent stress rupture factors for Grade 91 steel have been evaluated based on the consolidated database as a ratio of average creep rupture strength of cross weld test specimen to the average creep rupture strength of base metal.
Validation of the Moody and Henry–Fauske Critical Flow Models in apros Against Marviken Critical Flow Experiments
Authors: Tesinsky Milan
Published: February 2020

The Moody and Henry–Fauske critical flow models implemented in Advanced Process Simulation Software (apros) have been validated against Marviken critical flow experiments and compared with other available simulations of the same experiments. Both models in combination with discharge coefficient 0.75 (suggested for best estimate calculations) produce results close to the experimental data for two-phase flows, while one-phase flow of subcooled water is underpredicted. Using discharge coefficient 1.0 for subcooled water leads to a good match with the experimental results, while two-phase flows become overpredicted.
Tubular Locomotion and Positioning Using Tip Eversion for Endoscopy
Authors: Saxena Ankit , Pauli Eric M. , Haluck Randy S. , Fell Barry , Moore Jason
Published: February 2020

Colonoscopy is a minimally invasive procedure to examine the large intestine using a flexible endoscope. Currently, colonoscopic procedures require physically pushing the endoscope through the large intestine which potentially imparts damaging forces on the intestinal wall, requires a high level of expertise to perform safely, and can require extensive procedure time. This paper presents the use of inverted tubular element locomotion (ITEL) for improved endoscope translation and positioning that works via tip eversion of inverted plastic tubes. Experiments were performed to examine the fluid pressure required for locomotion through a large intestinal model and in both straight and curved paths and determine the optimal tube dimensions for insertion via ITEL. Experiments were then performed to compare intestinal forces during manual and ITEL-based insertion. The experiments established a relationship between the tip eversion pressure and the tube thickness and diameter. In addition, it was found that pressure required for locomotion was only minimally impeded by being enclosed in the intestinal manikin but significantly impacted by the curvature of the turn. Measured insertion forces for ITEL were found to be 10.1% less compared to traditional insertion. These results will aid in the future design and development of ITEL for endoscopic positioning.
Modal Control for Active Vibration Damping of Cable-Driven Parallel Robots
Authors: Cuvillon Loïc , Weber Xavier , Gangloff Jacques
Published: February 2020

Cable-driven parallel robots are well suited for applications that require a very large workspace. Thanks to their lightweight moving parts, they can achieve high dynamics while remaining pretty safe for nearby human workers. Furthermore, their size depends only on the length of the cables; thus, their scale is almost totally decoupled from their cost. However, due to the cables, the stiffness is very low with respect to rigid link robots, inducing slowly damped oscillations of the end effector. Previous works have shown that those vibrations can be effectively damped by the winch actuators thanks to active vibration damping techniques. In this paper, a gain scheduling approach is proposed based on a linearized model of the robot dynamics. This model is projected in the modal space yielding six decoupled transfer functions for six degrees-of-freedom (DoFs) of a cable-driven parallel robot using thin cables. The stability of the proposed control law is analyzed for a static and a moving end effector. The proposed control algorithm is validated experimentally on an eight-cable suspended robot prototype.
Efficient Spot Welding Sequence Optimization in a Geometry Assurance Digital Twin
Authors: Tabar Roham Sadeghi , Wärmefjord Kristina , Söderberg Rikard , Lindkvist Lars
Published: February 2020

A digital twin for geometry assurance contains a set of analyses that are performed to steer the real production for securing the geometry of the final assembly. In sheet metal assemblies, spot welding is performed to join the parts together. The sequence of the welding has a considerable influence on the geometrical outcome of the final assembly. In industry, the sequence of welding to secure the geometry is mainly derived by tacit manufacturing knowledge. Including such knowledge to mimic the production process requires extensive knowledge management, and the result might be just a good enough solution. Theoretically, spot welding sequence optimization for the optimal geometrical quality is among NP-hard combinatorial problems. In a geometry assurance digital twin, where assembly parameters are selected for the individual assemblies, time constraints define the quality of the optimal sequence. In this paper, an efficient method for spot welding sequence optimization with regards to the geometrical quality is introduced. The results indicate that the proposed method reduces 60–80% of the time for the sequencing of the spot welding process to achieve the optimal geometrical quality.
Heat Transfer Enhancement Analysis of Tube Receiver for Parabolic Trough Solar Collector With Central Corrugated Insert
Authors: Benabderrahmane Amina , Benazza Abdelylah , Hussein Ahmed Kadhim
Published: February 2020

Tube receiver with central corrugated insert was introduced as the absorber tube of parabolic trough receiver to increase the overall heat transfer performance of the tube receiver for parabolic trough solar collector (PTC) system. The Monte Carlo ray tracing method (MCRT) coupled with finite volume method (FVM) was adopted to investigate flow characteristics and the heat transfer performance of tube receiver for parabolic trough solar collector system. The numerical results were successfully validated with the empirical correlations existing in the literature. The numerical results indicated that the introduction of the corrugated insert inside the absorber tube of the parabolic trough receiver can effectively enhance the heat transfer performance, where the average Nusselt number can be increased up to 3.7 times compared to the smooth absorber. While the overall heat transfer performance factor can be found to be in the range of 1.3–2.6. The results indicate that the heat transfer increases with increasing corrugated insert twist ratio and increases also with decreasing pitch between two corrugations.
Experimental and Numerical Investigations on the Heat Transfer of Film Cooling With Cylindrical Holes Fed With Internal Coolant Cross Flows
Authors: Ye Lin , Liu Cun-Liang , Zhou Dao-En , Zhu Hui-Ren
Published: February 2020

The heat transfer coefficient of cylindrical holes fed by varying internal cross-flow channels with different cross-flow Reynolds numbers Rec is experimentally studied on a low-speed flat-plate facility. Three coolant cross flow cases, including a smooth case and two ribbed cases with 45/135-deg ribs, are studied at Rec = 50,000, and 100,000 with varying blowing ratios M of 0.5, 1.0, and 2.0. A transient liquid-crystal (LC) measurement technique is used to determine the heat transfer coefficient. At lower M, the heat transfer enhancement regions are asymmetrical for the smooth and 45-deg cases. The asymmetrical vortex is more pronounced with increasing cross-flow direction velocity, resulting in a more skewed distribution at Rec = 100,000. Conversely, the contours are laterally symmetric in the 135-deg case at varying Rec. A fork-shaped trend with a relatively high heat transfer coefficient appears upstream, and the increases in the heat transfer in the 135-deg cases are lower than those in the 45-deg cases. As M increases to 2.0, the vortex intensity increases, resulting in a stronger scouring effect upstream, especially at large Rec. The range and degree are affected by Rec at M = 2.0. The core of the heat transfer enhancement is skewed to the −Y side for both cases.
Porosity Manipulation in Bottom-Enclosed Vertical Porous Structure to Improve Natural Convection Cooling Efficacy: A Computational Study
Authors: Dasgupta Subhashish , Gupta Abhishek
Published: February 2020

Flow acceleration by imposing flow channelization structures like chimneys and/or solid barriers to improve natural convection cooling in pure fluids, is a well-known technique and a thoroughly investigated topic in thermal engineering. However, accelerating flow through porous media, by using such a passive technique, is challenging due to restriction imposed by the solid matrix to the erection of such structures. This study is a unique investigation into a passive method to accelerate flow in natural convection cooling through a bottom-enclosed porous medium with a vertical heated structure at the center, a configuration that is commonly encountered in industry. The porous domain is divided into distinct zones varying in porosity while retaining the average porosity of the original system, to ensure enough structural stability to the vertical heating element. Employing computational fluid dynamics (CFD) analyses, the study shows that the method has the potential to significantly improve natural convection cooling by accelerating flow in tall porous structures while at the same time improves mechanical stability of such structures.
An Inverse Method to Predict NEMS Beam Properties From Natural Frequencies
Authors: Liem Alyssa T. , Ari Atakan B. , McDaniel J. Gregory , Ekinci Kamil L.
Published: February 2020

This paper presents a method to simultaneously predict the elastic modulus, axial load, and boundary conditions of a nanoelectromechanical system (NEMS) beam from a minimum of two measured natural frequencies. The proposed method addresses the challenges of the inverse problem at the nano scale, which include high natural frequencies, small geometric beam dimensions, and measurements limited to natural frequencies. The method utilizes a finite element model of an Euler–Bernoulli beam under axial loading to predict the response of the beam with axial loading and flexible boundary conditions. By expressing the finite element model in terms of dimensionless beam parameters, the proposed method may be applied to nano scale beams while maintaining numerical stability of the finite element equation of motion. With the stabilized finite element model, the NEMS beam properties are predicted by iterating through values of dimensionless beam parameters until the normalized error between predicted and measured natural frequencies is minimized. A key feature of the proposed method is the simultaneous prediction of the elastic modulus during the iterative search, resulting in a reduction of the search space and significant computational savings. Additionally, the proposed method readily accommodates an arbitrary number of measured natural frequencies without the reformulation of procedures and analyses. Numerical examples are presented to illustrate the proposed method’s ability to predict the elastic modulus, axial load, and boundary conditions. The proposed method is applied to experimental measurements of a NEMS beam, where the normalized error between predicted and measured natural frequencies is reduced below 10−3.
Understanding Contemplators’ Knowledge and Awareness of the Physical Activity Guidelines
Authors: Piercy Katrina L. , Bevington Frances , Vaux-Bjerke Alison , Hilfiker Sandra Williams , Arayasirikul Sean , Barnett Elizabeth Y.
Published: February 2020

Background: The Office of Disease Prevention and Health Promotion completed research to understand factors that could encourage Americans to follow the Physical Activity Guidelines for Americans, second edition, released in 2018. This study describes survey research assessing demographic characteristics that might be related to knowledge and awareness of the guidelines. Methods: An online survey of 2050 adult physical activity contemplators assessed knowledge of physical activity, awareness of the guidelines, and knowledge of dosage recommendations. Univariate and bivariate analyses were performed, and demographic differences in knowledge and awareness were analyzed using Pearson chi-square tests and Fisher exact tests. Results: Respondents had medium to high knowledge of physical activity, although knowledge varied significantly by socioeconomic factors. Knowledge of dosage recommendations was very low, with 2% and 3% of respondents correctly identifying recommended moderate- and vigorous-intensity doses, respectively. Only 22% were aware of the guidelines; awareness was greater among those with a higher education or income and those without a disability. Conclusions: These findings guided the development of the Office of Disease Prevention and Health Promotion’s Move Your Way campaign and reinforced the need to raise awareness of the guidelines and promote behavior change among physical activity contemplators—particularly those from lower socioeconomic groups.
Bend Don’t Break: Stretching Improves Scores on a Battery of Fall Assessment Tools in Older Adults
Authors: Johnson Nathan F. , Hutchinson Chloe , Hargett Kaitlyn , Kosik Kyle , Gribble Phillip
Published: February 2020

Context: Falls and loss of autonomy are often attributed in large part to musculoskeletal impairments in later adulthood. Age-related declines in flexibility contribute to late adulthood musculoskeletal impairment. The novel sitting-rising test has been proposed to be a quick, effective screening of musculoskeletal fitness, fall risk, and all-cause mortality in older adults. The timed up and go and 5 times sit-to-stand tests are two of the 3 most evidence-supported performance measures to assess fall risk. Objective: This study aimed to determine if 5 weeks of flexibility training could increase sitting-rising test, timed up and go, and 5 times sit-to-stand scores in community-dwelling older adults. Participants: Forty-seven adults aged 60 years and older (mean age = 66.7 y, SD = 4.1) participated in this study. Participants completed a static stretching protocol consisting of 3 weekly 1-hour stretching sessions. Results: The protocol improved flexibility as seen in sit-and-reach scores and improved scores on all outcome variables. Specifically, there was a significant increase in sitting-rising test scores from preintervention (M = 7.45, SD = 1.45) to postintervention (M = 8.04, SD = 1.36), t(42) = −5.21, P < .001. Timed up and go scores demonstrated a significant decrease from preintervention (M = 8.85, SD = 1.32) to postintervention (M = 8.20, SD = 1.35), t(46) = 5.10, P < .001. Five times sit-to-stand scores demonstrated a significant decrease from preintervention (M = 12.57, SD = 2.68) to postintervention (M = 10.46, SD = 2.06), t(46) = 6.62, P < .001. Finally, significant increases in sit-and-reach scores were associated with improved functional performance (r = −.308, P = .03). Conclusion: Findings suggest that flexibility training can be an effective mode of low-level exercise to improve functional outcomes. Static stretching may help to improve musculoskeletal health, promote autonomy, and decrease mortality in community-dwelling older adults.
Comment on “The intensification of the water footprint of hydraulic fracturing”
Authors: Raimi Daniel
Published: February 2020

Kondash
et al
. incorrectly claim that water intensity has increased in all regions, and several data errors are apparent.
Photothermally induced transparency
Authors: Ma Jinyong , Qin Jiayi , Campbell Geoff T. , Lecamwasam Ruvi , Sripathy Kabilan , Hope Joe , Buchler Ben C. , Lam Ping Koy
Published: February 2020

Photothermal-cavity nonlinearity induces a new transparency effect with demonstrated agreement between model and experiment.
Excitons in 2D perovskites for ultrafast terahertz photonic devices
Authors: Kumar Abhishek , Solanki Ankur , Manjappa Manukumara , Ramesh Sankaran , Srivastava Yogesh Kumar , Agarwal Piyush , Sum Tze Chien , Singh Ranjan
Published: February 2020

The quantum well in 2D perovskite provides an additional channel for photoexcited electrons to relax back at ultrafast time scale.
Additive manufacturing of cellulose-based materials with continuous, multidirectional stiffness gradients
Authors: Giachini P. A. G. S. , Gupta S. S. , Wang W. , Wood D. , Yunusa M. , Baharlou E. , Sitti M. , Menges A.
Published: February 2020

We combine materials engineering and digital processing to design and print cellulose-based continuous stiffness gradients.
Light-induced control of protein destruction by opto-PROTAC
Authors: Liu Jing , Chen He , Ma Leina , He Zhixiang , Wang Dong , Liu Yi , Lin Qian , Zhang Tinghu , Gray Nathanael , Kaniskan H. Ümit , Jin Jian , Wei Wenyi
Published: February 2020

Opto-PROTAC adds a light-inducible switch on PROTAC, enabling optical control for targeted degradation of proteins of interest
.
Facile diamond synthesis from lower diamondoids
Authors: Park Sulgiye , Abate Iwnetim I. , Liu Jin , Wang Chenxu , Dahl Jeremy E. P. , Carlson Robert M. K. , Yang Liuxiang , Prakapenka Vitali B. , Greenberg Eran , Devereaux Thomas P. , Jia Chunjing , Ewing Rodney C. , Mao Wendy L. , Lin Yu
Published: February 2020

Diamondoids are promising precursors for facile diamond synthesis using laser-induced high-pressure, high-temperature conditions.
Defining the emergence of myeloid-derived suppressor cells in breast cancer using single-cell transcriptomics
Authors: Alshetaiwi Hamad , Pervolarakis Nicholas , McIntyre Laura Lynn , Ma Dennis , Nguyen Quy , Rath Jan Akara , Nee Kevin , Hernandez Grace , Evans Katrina , Torosian Leona , Silva Anushka , Walsh Craig , Kessenbrock Kai
Published: February 2020

Alshetaiwi
et al.
identify CD84 to be a robust MSDC-specific cell surface marker in breast cancers.
Effects of dietary Bacillus subtilis RX7 and B2A supplementation on productive performance, egg quality, blood profiles, and excreta Salmonella counts in laying hens
Authors: Shi Huan , Zhang Wan Lin , Kim In Ho
Published: February 2020

An experiment was carried out to investigate the effect of Bacillus subtilis RX7 and B2A supplementation on egg production, egg quality, blood profile, and excreta Salmonella population in laying hens. A total of 192 Hy-Line Brown laying hens (40-wk-old) were randomly assigned into four dietary treatments, each of which was replicated eight times with six hens per replicate in a 5 wk trial. The dietary treatments were NC, which is a basal diet without antibiotics or Bacillus subtilis; PC, which is an NC + 0.5 g kg−1 antibiotic (virginiamycin) diet; BSR, which is an NC + 0.5 g kg−1 Bacillus subtilis RX7 (1.0 × 109 colony forming units g−1); and BSB, which is an NC + 0.5 g kg−1 Bacillus subtilis B2A (1.0 × 109 colony forming units g−1). The results showed that hens receiving BSB diets had increased (P < 0.05) eggshell thickness over hens fed the NC, PC, and BSR diets (week 3). The excreta Salmonella counts in the PC, BSR, and BSB groups were lower than the NC group (P < 0.05). These results indicate that dietary inclusion of Bacillus subtilis RX7 and B2A strains effectively decreased excreta Salmonella counts without any detrimental effects on the performance of laying hens.
Spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) at the northern limit of their native range
Authors: Deakin Samuel , Gorrell Jamieson C. , Kneteman Jeffery , Hik David S. , Jobin Richard M. , Coltman David W.
Published: February 2020

The Canadian Rocky Mountains are one of the few places on Earth where the spatial genetic structure of wide-ranging species has been relatively unaffected by anthropogenic disturbance. We characterized the spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw, 1804) in the northern portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA sequences from 188 individuals, we examined both broad- and fine-scale spatial genetic structure, assessed sex-biased gene flow within the northern portion of the species range, and identified geographic patterns of genetic diversity. We found that broad-scale spatial genetic structure was consistent with barriers to movement created by major river valleys. The fine-scale spatial genetic structure was characterized by a strong isolation-by-distance pattern, and analysis of neighborhood size using spatial autocorrelation indicated gene flow frequently occurred over distances of up to 100 km. However, analysis of sex-specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing genetic diversity with increasing latitude, consistent with patterns of post-glacial recolonization of the Rocky Mountains.
Effect of welding parameters on mechanical and corrosion behavior of Stellite 6 cladded SA387 Gr 91 with ERNiCr-3 buffer layer
Authors: Britto Joseph G. , Valarmathi T.N. , John Rajan A.
Published: February 2020

The mechanical, chemical, and corrosion properties of a cladded material strongly depends upon the geometry of the clad beads. Hence, it is essential to learn the impact of process parameters on the weld bead geometry. In this work, the effects of welding speed, welding current, and nozzle-to-plate distance on cladding were investigated in terms of improving the mechanical and corrosion properties. SA387 Gr 91 was cladded with Stellite 6 as cladding material and ERNiCr-3 as a buffer layer by a IRB1520 ID robotic welding machine. The experiments were carried out using three factors with three levels as per the Box–Behnken design technique. A characterization study was made using an optical microscope and scanning electron microscope. The hardness was measured using a Vicker’s hardness tester. An electrochemical corrosion test was conducted to determine the corrosion resistance. The application of ERNiCr-3 reduced the formation of cracks and pores on the surface of the cladded metal. Among the chosen parameters, welding current was the most important parameter controlling the mechanical and corrosion properties. From the results, it is concluded that the combination of ERNiCr-3 and Stellite 6 enhances the corrosion resistance and mechanical properties of SA387 Gr 91 significantly.
Continuous phase transition and microstructure of charged AdS black hole with quintessence
Authors: Guo Xiong-Ying , Li Huai-Fan , Zhang Li-Chun , Zhao Ren
Published: February 2020

Previously, the Maxwell equal-area law has been used to discuss the conditions satisfied by the phase transition of charged AdS black holes with cloud of string and quintessence, and it was concluded that black holes have phase transition similar to that of vdW system. The phase transition depends on the electric potential of the black hole and is not the one between a large black hole and a small black hole. On the basis of this result, we study the relation between the latent heat of the phase transition and the parameter of dark energy, and use the Landau continuous phase transition theory to discuss the critical phenomenon of the black hole with quintessence and give the critical exponent. By introducing the number density of the black hole molecules, some properties of the microstructure of black holes are studied in terms of a phase transition. It is found that the electric charge of the black hole and the normalization parameter related to the density of quintessence field play a key role in the phase transition. By constructing the binary fluid model of the black hole molecules, we also discuss the microstructure of charged AdS black holes with a cloud of strings and quintessence.
Light quark masses in $${N_\mathrm{f}=2+1}$$ lattice QCD with Wilson fermions
Authors: Bruno M. , Campos I. , Fritzsch P. , Koponen J. , Pena C. , Preti D. , Ramos A. , Vladikas A.
Published: February 2020

We present a lattice QCD determination of light quark masses with three sea-quark flavours ($$N_\mathrm{f}=2+1$$Nf=2+1). Bare quark masses are known from PCAC relations in the framework of CLS lattice computations with a non-perturbatively improved Wilson-Clover action and a tree-level Symanzik improved gauge action. They are fully non-perturbatively improved, including the recently computed Symanzik counter-term $$b_{\mathrm{A}} - b_{\mathrm{P}}$$bA-bP. The mass renormalisation at hadronic scales and the renormalisation group running over a wide range of scales are known non-perturbatively in the Schrödinger functional scheme. In the present paper we perform detailed extrapolations to the physical point, obtaining (for the four-flavour theory) $$m_{\mathrm{u}/\mathrm{d}}(2~\mathrm{GeV})= 3.54(12)(9)~\mathrm{MeV}$$mu/d(2GeV)=3.54(12)(9)MeV and $$m_{\mathrm{s}}(2~\mathrm{GeV}) = 95.7(2.5)(2.4)~\mathrm{MeV}$$ms(2GeV)=95.7(2.5)(2.4)MeV in the $$\overline{\mathrm{MS}}$$MS¯ scheme. For the mass ratio we have $$m_{\mathrm{s}}/m_{\mathrm{u}/\mathrm{d}}= 27.0(1.0)(0.4)$$ms/mu/d=27.0(1.0)(0.4). The RGI values in the three-flavour theory are $$M_{\mathrm{u}/\mathrm{d}}= 4.70(15)(12)~\mathrm{MeV}$$Mu/d=4.70(15)(12)MeV and $$M_{\mathrm{s}}= 127.0(3.1)(3.2)~\mathrm{MeV}$$Ms=127.0(3.1)(3.2)MeV.
Kinetic energy properties and weak equivalence principle in a space with generalized uncertainty principle
Authors: Gnatenko Kh. P. , Tkachuk V. M.
Published: February 2020

A space with deformed commutation relations for coordinates and momenta leading to generalized uncertainty principle (GUP) is studied. We show that GUP causes great violation of the weak equivalence principle for macroscopic bodies, violation of additivity property of the kinetic energy, dependence of the kinetic energy on composition, great corrections to the kinetic energy of macroscopic bodies. We find that all these problems can be solved in the case of arbitrary deformation function depending on momentum if parameter of deformation is proportional inversely to squared mass.
Equilibrium stellar configurations in Rastall theory and astrophysical implications
Authors: Hansraj Sudan , Banerjee Ayan
Published: February 2020

Rastall theory propounded some five decades ago belongs to a class of modified theories of gravity. Such theories are motivated by the need to modify general relativity suitably in order to address some problems not explained by the standard theory. Amongst such issues are the observed accelerated expansion of the universe, motion in extremely high gravity regimes and explanations for the discrepancy in the value of the cosmological constant between quantum gravity and experimentation. Recently, it has been claimed that the Rastall theory is trivially equivalent to the standard Einstein theory. We investigate this claim in the context of stellar structure and elementary requirements for physical plausibility. We consider the analogue of the Saslaw et al. [Astrophys. J. 471, 571 (1996)] isothermal model of general relativity and show that the Rastall version satisfies the basic requirements unlike its counterpart. Then, we examine in turn the consequences of suppressing one of the inverse square law fall off of the energy density or the linear equation of state. Imposing a linear barotropic equation of state, we find a generalized de Sitter spacetime as an exact solution of the Rastall equations. In addition, the case of a constant spatial gravitational potential is studied. In each case, we note that the physics of the Rastall model differs from that of the Einstein version.
On the quantum improved Schwarzschild black hole
Authors: Moti R. , Shojai A.
Published: February 2020

Deriving the gravitational effective action directly from exact renormalization group is very complicated, if not impossible. Hence, to study the effects of running gravitational coupling which tends to a non-Gaussian UV fixed point (as it is supposed by the asymptotic safety conjecture), two steps are usually adopted. Cutoff identification and improvement of the gravitational coupling to the running one. As suggested in Ref. 1, a function of all independent curvature invariants seems to be the best choice for cutoff identification of gravitational quantum fluctuations in curved space–time and makes the action improvement, which saves the general covariance of theory, possible. Here, we choose Ricci tensor square for this purpose and then the equation of motion of improved gravitational action and its spherically symmetric vacuum solution are obtained. Indeed, its effect on the massive particles’ trajectory and the black hole thermodynamics is studied.
Spin-dependent group delay time and Hartman effect in ferromagnetic bilayer graphene superlattice
Authors: Sattari Farhad , Mirershadi Soghra , Hamdipour Mohammad , Majidi Farshad
Published: February 2020

We theoretically study the spin-dependent group delay time through ferromagnetic bilayer graphene superlattice in the absence and presence of the bandgap. It is found that the group delay time depends on the spin degree of freedom and exhibits an oscillatory behavior with respect to the Fermi energy and barrier width. Furthermore, in the absence of the bandgap, the superluminal or Hartman effect exists only for the normal angle of incidence. Moreover, when bandgap value is large enough [Formula: see text], the Hartman effect can be observed for all angles of incidence. These results are contrary to the observed behavior for monolayer graphene superlattice.
Fisher information of accelerated two-qubit system in the presence of the color and white noisy channels
Authors: Metwally N. , Ebrahim F.
Published: February 2020

In this paper, an accelerated two-qubit system initially prepared in maximum or partial entangled state, which interacts locally with white/color or white-color noises, is considered. Due to the acceleration process and the noise effect, the entanglement degraded. Therefore, the effect of noise strength, initial state settings and the acceleration on the survival entanglement are investigated by means of the concurrence. Moreover, the initial parameters that describe this system are estimated by using the quantum Fisher information, where two forms are considered, namely by using a single and two-qubit forms. It is shown that, by using the two-qubit form, the estimation degree of these parameters is larger than that displayed by using a single-qubit form.
Degradation of bromobenzene via external electric field
Authors: Chen Yu , Liu Yuzhu , Zhang Qihang , Yan Yihui , Yin Wenyi
Published: February 2020

Bromobenzene is one of the organic pollutants that damage the natural environment and poses a serious threat to human health. Therefore, it is meaningful to study its degradation characteristics under the electric field. In this paper, density functional theory (DFT) at BPV86/6-311G (d, p) level are employed for the study of C–Br bond distance, total energy, charge distribution, dipole moment, lowest unoccupied molecular orbital (LUMO) level, highest occupied molecular orbital (HOMO) level, energy gap and potential energy surface (PES) of bromobenzene in external electric field ([Formula: see text]15.43[Formula: see text]V[Formula: see text][Formula: see text][Formula: see text]nm[Formula: see text]–15.43[Formula: see text]V[Formula: see text][Formula: see text][Formula: see text]nm[Formula: see text]). It shows that as the electric field increases, the C–Br bond tends to break. The changes in the HOMO level and the LUMO level result in a rapid drop in the energy gap. In addition, the dissociation barrier gradually decreases. When the applied electric field reaches 15.43[Formula: see text]V[Formula: see text][Formula: see text]nm[Formula: see text], the dissociation barrier disappears completely, which means that the C–Br bond is broken and bromobenzene is degraded.
DFT studies on the diastereoselectivity and regioselectivity of multicomponent domino Knoevenagel/Diels–Alder reaction
Authors: Attarbashi Mina , Shiraz Nader Zabarjad , Samadizadeh Marjaneh
Published: February 2020

In this study, mechanism and stereochemistry of multicomponent domino Knoevenagel/Diels–Alder reaction were investigated theoretically. Structures of reagents, transition states, intermediates, and products were optimized at M062X/6-31[Formula: see text]G(d,p) level of theory. Although the mechanism of this reaction involved several processes, including bond rotation, isomerization, asymmetric cycloaddition, acid-base, and nucleophile–electrophile competitions, critical processes were studied to provide a clearer picture of the mechanism of this valuable reaction in terms of stereochemistry considerations. According to the results, the ring closure step of reaction performed via a polar Dield-Alder mechanism, having enthalpy at approximately 40[Formula: see text]kcal/mol. The diastereoselectivity of the reaction was controlled by the interaction of dienophile with the less hindered face of diene through a more stable endo transition state ([Formula: see text] and 27.31 in methanol and gas phase, respectively). HSAB criteria could explain the regioselectivity of this reaction by considering the least softness difference ([Formula: see text]) for interacting C-atoms based on Hirshfeld populations. The result was the creation of cis-spiro cyclohexanone under kinetic and thermodynamic controls as a predominant diastereoselective and regioselective product.
Layer-by-Layer Biomaterials for Drug Delivery
Authors: Alkekhia Dahlia , Hammond Paula T. , Shukla Anita
Published: February 2020

Controlled drug delivery formulations have revolutionized treatments for a range of health conditions. Over decades of innovation, layer-by-layer (LbL) self-assembly has emerged as one of the most versatile fabrication methods used to develop multifunctional controlled drug release coatings. The numerous advantages of LbL include its ability to incorporate and preserve biological activity of therapeutic agents; coat multiple substrates of all scales (e.g., nanoparticles to implants); and exhibit tuned, targeted, and/or responsive drug release behavior. The functional behavior of LbL films can be related to their physicochemical properties. In this review, we highlight recent advances in the development of LbL-engineered biomaterials for drug delivery, demonstrating their potential in the fields of cancer therapy, microbial infection prevention and treatment, and directing cellular responses. We discuss the various advantages of LbL biomaterial design for a given application as demonstrated through in vitro and in vivo studies.
Mechanosensitive Ion Channels: Structural Features Relevant to Mechanotransduction Mechanisms
Authors: Jin Peng , Jan Lily Yeh , Jan Yuh-Nung
Published: February 2020

Activation of mechanosensitive ion channels underlies a variety of fundamental physiological processes that require sensation of mechanical force. Different mechanosensitive channels adapt distinctive structures and mechanotransduction mechanisms to fit their biological roles. How mechanosensitive channels work, especially in animals, has been extensively studied in the past decade. Here we review key findings in the functional and structural characterizations of these channels and highlight the structural features relevant to the mechanotransduction mechanism of each specific channel.
The Anatomy and Physiology of Claustrum-Cortex Interactions
Authors: Jackson Jesse , Smith Jared B. , Lee Albert K.
Published: February 2020

The claustrum is one of the most widely connected regions of the forebrain, yet its function has remained obscure, largely due to the experimentally challenging nature of targeting this small, thin, and elongated brain area. However, recent advances in molecular techniques have enabled the anatomy and physiology of the claustrum to be studied with the spatiotemporal and cell type–specific precision required to eventually converge on what this area does. Here we review early anatomical and electrophysiological results from cats and primates, as well as recent work in the rodent, identifying the connectivity, cell types, and physiological circuit mechanisms underlying the communication between the claustrum and the cortex. The emerging picture is one in which the rodent claustrum is closely tied to frontal/limbic regions and plays a role in processes, such as attention, that are associated with these areas.
A Novel Attentive Generative Adversarial Network for Waterdrop Detection and Removal of Rubber Conveyor Belt Image
Authors: Li Xianguo , Liu Zongpeng , Li Bin , Feng Xinxin , Liu Xiao , Zhou Debao
Published: February 2020

The lens for monitoring the rubber conveyor belt is easy to adhere to a large number of water droplets, which seriously affects the image quality and then affects the effect of fault monitoring. In this paper, a new method for detecting and removing water droplets on rubber conveyor belts based on the attentive generative adversarial network is proposed to solve this problem. First, the water droplet image of the rubber conveyor belt is input into the generative network composed of a cyclic visual attentive network and an autoencoder with skip connections, and an image of removing water droplets and an attention map for detecting the position of the water droplet are generated. Then, the generated image of removing water droplets is evaluated by the attentive discriminant network to assess the local consistency of the water droplet recovery area. In order to better learn the water droplet regions and the surrounding structures during the training, the image morphology is added to the precise water droplet regions. A dewatered rubber conveyor belt image is generated by increasing the number of circular visual attention network layers and the number of skip connection layers of the autoencoder. Finally, a large number of comparative experiments prove the effectiveness of the water droplet image removal algorithm proposed in this paper, which outperforms of Convolutional Neural Network (CNN), Discriminative Sparse Coding (DSC), Layer Prior (LP), and Attention Generative Adversarial Network (ATTGAN).
Corneal Reinnervation and Sensitivity Recovery after Pterygium Excision
Authors: Zhao ZhanLin , Zhang JiaYing , Liang Hong , Zhang SiYi , Shao ChunYi , Fan XianQun , Fu Yao
Published: February 2020

Purpose. To evaluate changes in corneal sensitivity and subbasal nerve density after pterygium excision. Methods. This prospective trial included 22 eyes with nasal primary pterygium and 18 controls. Corneal sensitivity was evaluated using a Cochet–Bonnet esthesiometer in the nasal, superior, temporal, inferior, and center quadrants of the cornea before surgery and 10 days, 1 month, and 3months after surgery. The central cornea was analyzed using in vivo confocal microscopy (IVCM) before surgery and 1 and 3 months after surgery. Subbasal nerve density and other nerve parameters were analyzed using NeuronJ. Nerve tortuosity was evaluated and graded in individual IVCM scans. The tear film break-up time (TBUT) test and Schirmer’s test were performed before surgery, as well as 1 and 3 months after surgery. All the same tests were performed in the controls. Results. All affected eyes showed a significant increase in corneal sensitivity in the nasal corneal quadrant after surgery when compared with preoperative data (F = 37.3; P<0.01). Compared with controls, pterygium patients demonstrated decreased corneal subbasal nerve density (P<0.01), fewer nerve trunks (P<0.01), and fewer nerve branches (P<0.05). However, an increased central corneal subbasal nerve density was observed 1 month after surgery compared with preoperative data, after which the density became stable (F = 9.62; P<0.01). Nerve tortuosity showed no difference between the two groups or across different time points in patients. Similarly, patients with pterygium demonstrated a decrease in TBUT (P<0.01) when compared with controls. A tendency toward increase was observed in the TBUT test after pterygium excision (F = 2.873; P=0.07). However, no difference was observed in Schirmer’s test. Conclusion. Pterygium patients demonstrated deteriorated corneal subbasal nerve fibers when compared with healthy controls in terms of nerve length, nerve trunks, and nerve branches. Therefore, pterygium excision improves corneal sensitivity and increases corneal subbasal nerve density.
Influence of Loosely Bound Water on Compressibility of Compacted Fine‐Grained Soils
Authors: Zhang Rui , Wu Mengli , Kumar Prince , Gao Qian-Feng
Published: February 2020

This study aimed to investigate the influence of loosely bound water (LBW) on the compressibility of compacted fine‐grained soils and accurately determine the soil’s compression index. Four fine‐grained soils (i.e., heavy clay, heavy silt, lean clay, and lean silt) and a coarse‐grained soil were examined. The volumetric flask method was used to measure the LBW contents of the five soils. X‐ray diffraction (XRD) analysis was then performed to test the mineral compositions and help explain the reason why the LBW content varied between different soils. A concept of modified void ratio was proposed by assuming that LBW is a part of the solid phase in soil. Subsequently, consolidation tests and permeability tests were conducted on saturated compacted specimens. The results show that the compression indexes or permeability coefficients tend to be the same for the soils with identical initial modified void ratios. Consolidation tests were also carried out on the unsaturated compacted heavy silt of four different dry densities prepared at a water content higher than the optimum. They show that the compression of unsaturated soil occurs if pore air is discharged when the water content is less than the LBW content. This confirms the previous assumption that LBW can be regarded as a part of the soil solid phase. A modified compression index was deduced and implemented to predict the settlement of a road embankment. The result suggests that the modified compression index is capable of calculating the compression of fine‐grained soils, whose water contents are higher than their LBW contents.
Fasting Neurotensin Levels in Pediatric Celiac Disease Compared with a Control Cohort
Authors: Iorfida Donatella , Montuori Monica , Trovato Chiara Maria , Tiberti Claudio , Sansone Andrea , Cucchiara Salvatore , Valitutti Francesco
Published: February 2020

Background and Aims. Neurotensin (NT) is a gut hormone secreted by specific endocrine cells scattered throughout the epithelial layer of the small intestine, which has been identified as an important mediator in several gastrointestinal functions and disease conditions. Its potential involvement in celiac disease (CD) has been investigated, but there are conflicting findings. The aim of this study was to evaluate serum NT levels in children with CD at diagnosis, compared to a control group, and to investigate whether NT correlated in CD patients with symptoms, antibody response, and intestinal mucosal damage.Materials and Methods. Children (1-16 years old) undergoing gastrointestinal endoscopy for CD or for other clinical reasons were included in this study. Patients with CD diagnosed according to the 2012 European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines without biopsy were also recruited. Fasting serum samples were analyzed for NT levels using ELISA. Logistic regression, Wilcoxon rank sum, and Spearman’s rank tests were used for statistical analysis.Results. Thirty children (18 females, 2.2-15.9 years old) were enrolled. Of 25 patients who underwent endoscopy, 9 were CD patients, 13 were controls, and 3 were excluded due to nonspecific inflammation at duodenal biopsy. CD was diagnosed in 5 patients without biopsy. NT median was higher in CD patients compared to controls (13.25 (IQR 9.4-17.5) pg/ml vs. 7.8 (IQR 7.6-10) pg/ml;p=0.02). No statistically significant association between NT and clinical, serological, or histological data of CD was observed in this CD cohort.Conclusions. To our knowledge, this is the first study that evaluates NT in CD children from Italy. Results show that NT is higher in the serum of CD children at diagnosis compared to controls. However, larger-scale studies are required to validate these findings. Whether serum NT levels can be an adjunctive marker for pediatric CD remains currently elusive.
Long-Term Outcome of Vitrectomy with Suitable Internal Limiting Membrane Peeling and Air Tamponade for Highly Myopic Foveoschisis-Associated Lamellar Macular Hole
Authors: Wang Jia-lin , Wang Yan-ling
Published: February 2020

Purpose. To investigate the outcome of pars plana vitrectomy (PPV) with suitable internal limiting membrane peeling (ILM) and air tamponade for patients with highly myopic foveoschisis-associated lamellar macular hole (MH). Methods. This retrospective interventional case series included 11 patients with highly myopic foveoschisis-associated lamellar MH who underwent PPV and indocyanine green-aided ILM peeling up to the temporal vascular arcades. Following air tamponade after surgery, all patients were instructed to maintain a face-down position. The patients were followed up for over 1 year and evaluated for MH closure and the best-corrected visual acuity before and after surgery. Results. The mean ± standard deviation values of patient age, axial length, and follow-up duration were 67.82 ± 6.54 years, 29.21 ± 1.95 mm, and 24.27 ± 8.11 months, respectively. After surgery, the lamellar MH closed in all eyes, and 10 eyes showed vision improvement at the 1-month, 3-month, and final follow-up evaluations. One patient showed decreased vision at 2 years after surgery, with patchy chorioretinal atrophy in the macular region. Myopic foveoschisis showed resolution in three eyes and alleviation in eight. Ten patients underwent cataract surgery during PPV. Conclusion. Extension of ILM peeling up to the temporal vascular arcades and air tamponade after PPV may improve the visual function and rate of MH closure for patients with highly myopic foveoschisis-associated lamellar MH.