bluuebunny/crossref_metadata_2025 huggingface dataset:
Height determination of single-layer graphene on mica at controlled humidity using atomic force microscopy
Authors: Lee Hyunsoo , Park Jeong Young
Published: October 2019

Identifying the thickness of the first graphene layer on a substrate is important in graphene-based nanoelectromechanical systems because of the dependence of graphene layers on physical and chemical properties. Identifying the thickness of the first layer is important for determining the number of graphene layers. Herein, we report that the height of single-layer graphene on mica is influenced by the relative humidity in the observation environment and by the scanning modes of in situ atomic force microscopy (AFM). We found that the graphene height is quite dependent on the scan direction of the AFM probe when in the contact mode, while this hysteresis is absent in tapping and noncontact modes. In addition, at low humidity (<10%), the height of the graphene on mica corresponds to the van der Waals distance (∼0.34 nm) of graphite layers, while an increased height (0.67 nm) is observed at higher humidity (≥20%). We associate the variation of the graphene height in the contact mode with different levels of tilting of the cantilever that are clearly dependent on the scanning direction. These results suggest a standard for determining graphene thickness in humid air that is a critical factor for graphene-based electronic devices.
3 soliton solution to Sine-Gordon equation on a space scale
Authors: Hovhannisyan Gro
Published: October 2019

Hirota’s direct method is extended on a variable time-space scale. Using this extension, we construct 3-soliton solutions of the Sine-Gordon equation on a variable space scale. The determinant form of this solution is given as well.
Wind energy at remote islands in arctic region—A case study of Solovetsky islands
Authors: Ghani Rizwan , Kangash Aleksei , Virk Muhammad Shakeel , Maryandyshev Pavel , Mustafa Mohamad
Published: October 2019

This paper describes a case study of wind resource assessment and wind park design at the Solovetsky Islands, which are located in the Arctic region of northern Russia. The Solovetsky historical and cultural complex has been included in the list of UNESCO's World Heritage Sites. 18 years of data of wind climatology from the NASA Langley Research Center are used for wind resource assessment at the Solovetsky Islands for two different wind park locations. Computational fluid dynamics based numerical simulations are carried out for wind resource assessment and for the estimation of the resultant annual energy production (AEP) for both locations. To better understand wind flow physics and the effects of wind turbine wake effects, three different wake models are used for the numerical simulations. Analyses of seasonal weather effects on energy production show that wind power production at the Solovetsky Islands is higher during the winter period compared to the summer period, mainly due to higher wind speeds and air density at cold winter conditions. A preliminary case study about wind park layout optimization has also been carried out, where the results show an increase in AEP with the optimization of the wind park layout.
Theory of applying heat flow from thermostatted boundary walls: Dissipative and local-equilibrium responses and fluctuation theorems
Authors: Onuki Akira
Published: October 2019

We construct a microscopic theory of applying a heat flow from thermostatted boundary walls in the film geometry. We treat a classical one-component fluid, but our method is applicable to any fluids and solids. We express linear response of any variable B in terms of the time-correlation functions between B and the heat flows JK from the thermostats to the particles. Furthermore, the surface variables JK can be written in the form of space integrals of bulk quantities from the equations of motion. Owing to this surface-to-bulk relation, the steady-state response functions consist of dissipative and local-equilibrium parts, where the former gives rise to Fourier’s law with Green’s expression for the thermal conductivity. In the nonlinear regime, we derive the steady-state distribution in the phase space in the McLennan-Zubarev form from the first principles. Some fluctuation theorems are also presented.
Compact differential B-dot monitors for measuring current on a fast pulsed power generator
Authors: Weller M. E. , Esaulov A. A. , Presura R. , Novikov D. V.
Published: October 2019

Compact differential B-dots have been mounted on a fast pulsed power generator for experimental current measurements. The fast pulsed power generator is named Thunderbird, which is capable of 130 kA in ∼25 to 35 ns rise-time. A compact design (1.0 mm diameter loops in an 8.0 mm diameter body) of the B-dots has been implemented to match the need and specifications of the Thunderbird generator. The B-dots have been calibrated using a short circuit load geometry for two conditions, an uncompressed and a compressed pulse, with a circuit model, and results are shown.
Tunable control of extremely concentrated heat flux through a thermal manipulator
Authors: Hai Fengxun , Zhu Wei , Cao Lili , Yang Xiaoyi , Deng Yuan
Published: October 2019

It is crucial to effectively control the heat flux in thermal functional devices and electronic systems. Here, we numerically simulate and experimentally design a simple but effective thermal manipulator based on transformation thermodynamics, which is capable of realizing an extreme heat flux concentration in a small area and guiding the heat flux to the region we desired. The experimental results show that the thermal manipulator has compressed the heat flux from the line-shaped thermal source with an extremely high concentration efficiency of 91.1% and a region concentration ratio of 39.7. The temperature gradient in the small area is 4.42 K/mm, which is about 115% of the applied temperature gradient, indicating a very strong heat concentration capability. Furthermore, the thermal manipulator can physically rotate the heat flux under a constant temperature gradient through a diagonal thermal conduction vector as well. By concentrating and deflecting the heat flux, the extreme concentration and tunable control of the heat flux have been demonstrated, providing an effective thermal manipulating method for the heat flux control in the small area.
On the peripheral intensification of two-dimensional vortices in smaller-scale randomly forcing flow
Authors: Sutyrin G. G. , Radko T.
Published: October 2019

The evolution of a monopolar vortex embedded in the field of smaller-scale randomly forced vorticity is examined using fully nonlinear two-dimensional simulations at large Reynolds numbers. The vortex is considered to be compact if its angular momentum decreases with the radius on the scale comparable to the radius of maximum azimuthal velocity. The energy decays without forcing, while the vortex remains compact despite its viscous spreading. This scenario dramatically changes in the strong forcing regime, characterized by the substantial growth of the vortex energy due to the increase in velocity and angular momentum at the vortex periphery so that ultimately, the vortex transforms into a noncompact structure. The maximum of angular momentum redistribution is found to be proportional to the enstrophy of smaller-scale vorticity field. The results have important implications for better understanding the fate of vortices and physical mechanisms of energy transfer.
Adaptive pre-whiten filtering for the free induction decay transversal signal in weak magnetic detection
Authors: Liu Huan , Bin Junchi , Dong Haobin , Ge Jian , Liu Zheng , Yuan Zhiwen , Zhu Jun , Zhang Haiyang
Published: October 2019

The free induction decay (FID) transversal signal is always employed by a proton precession magnetometer (PPM) to evaluate the time-domain geomagnetic field. Nevertheless, the signal-to-noise ratio (SNR) is an important factor that severely affects the detection accuracy of the magnetic field due to uncontrollable interference sources, including random noise and power frequency noise. In this study, aiming to boost the SNR of the FID transversal signal, a novel filtering algorithm based on a prewhiten (PW) strategy is proposed and the PW filtering was combined with singular value decomposition (SVD) for further noise reduction. This method aims to generate adaptive PW input data before filtering, further decorrelating the noise to reduce the impact of varying noise levels in the received FID signals. The efficiency of the proposed joint filtering framework, dubbed PW-SVD, was evaluated by comparing with two state-of-the-art methods, i.e., SVD and principal component analysis and decomposition, using the same data. The results demonstrated that the proposed PW-SVD method obtained the smallest root mean square error and the highest signal-to-noise ratio improvement among all the compared methods, especially for the strong-noisy scenario, which enhances the environmental adaptability of a PPM.
Motion of objects embedded in lipid bilayer membranes: Advection and effective viscosity
Authors: Camley Brian A. , Brown Frank L. H.
Published: October 2019

An interfacial regularized Stokeslet scheme is presented to predict the motion of solid bodies (e.g., proteins or gel-phase domains) embedded within flowing lipid bilayer membranes. The approach provides a numerical route to calculate velocities and angular velocities in complex flow fields that are not amenable to simple Faxén-like approximations. Additionally, when applied to shearing motions, the calculations yield predictions for the effective surface viscosity of dilute rigid-body-laden membranes. In the case of cylindrical proteins, effective viscosity calculations are compared to two prior analytical predictions from the literature. Effective viscosity predictions for a dilute suspension of rod-shaped objects in the membrane are also presented.
High color rendering index and stable white light emitting diodes fabricated from lead bromide perovskites
Authors: Gao Zhiyuan , Wang Xingyi , Bai Yufei , Sun Chun , Liu Hanxin , Wang Le , Su Sijing , Tian Kangkai , Zhang Zi-Hui , Bi Wengang
Published: October 2019

The tunable wavelength and high photoluminescence quantum yield of metal halide perovskite quantum dots (QDs) make them an extraordinary material for white light-emitting diodes (WLEDs). However, when perovskites with different halides are mixed, anion exchange occurs between them, limiting the development of WLEDs based on the perovskite. Meanwhile, the red emitting perovskite containing iodine is not stable, which is also a problem to overcome. In this paper, only bromide perovskites were adopted to fabricate the WLED. Hence, the anion exchange reaction can be avoided during their mixing process. CsPbBr3 nanoplatelets, CsPbBr3 QDs, and Mn-doped PEA2PbBr4 nanosheets were used as the blue, green, and red components of the WLEDs, respectively. All these perovskites preserve high luminance and stability, especially the red emitting component. Thus, the WLED shows high efficiency and excellent stability. By adjusting the amounts of these perovskites, WLEDs with different color temperatures were achieved, and the color rendering index reached up to 94.
Flow boiling heat transfer in silicon microgaps with multiple hotspots and variable pin fin clustering
Authors: Lorenzini Daniel , Joshi Yogendra
Published: October 2019

Microfluidic interlayer cooling has been demonstrated as a practical solution for the vertical stacking of high power microelectronics. Although a considerable amount of studies has been presented for single phase cooling with this approach, the flow boiling features in more complex arrangements have not been as thoroughly studied. The embedded cooling of microelectronics is feasible with the use of dielectric refrigerants, which are ideally used in two-phase conditions in order to exploit the latent heat of vaporization. In the present investigation, the two-phase cooling in silicon microgaps is assessed under variable power and heat transfer surface area densities. The dielectric refrigerant HFE-7200 is used as the working fluid under flow boiling conditions, analyzing useful characteristics such as the two-phase flow regime, heat transfer, and pressure drop. The present investigation uses a numerical model that is capable of predicting the relevant features of flow boiling phenomena through a mechanistic phase-change model. The results from this study demonstrate that multiple hotspots with variable pin densities can be effectively controlled, with relatively uniform temperatures, under flow boiling conditions with dielectric fluids.
Single-spin vector analysis of strongly coupled nuclei in TOCSY NMR experiments
Authors: Nielsen Anders B. , Hansen Michael Ryan , Andersen Jørgen Ellegaard , Vosegaard Thomas
Published: October 2019

This paper presents a new way to represent the effect of complex radio-frequency (rf) pulse sequences on J-coupled nuclear spin systems. The model uses a vector representation of the single-spin interactions (chemical-shift and rf interactions) and provides a simple route to gain analytical insight into multipulse NMR experiments. The single-spin Hamiltonian is expressed in an interaction representation as Fourier components. These Fourier components are combined for the two spins to establish the averaged coupling term of the Hamiltonian. This effective Hamiltonian is fast to calculate as only single-spin rotations are used and followed by simple summation of numbers for reconstruction of given coupling interactions. The present method is used to gain analytical insight into the performance of the J-coupling transfer sequence DIPSI-2 through two figures of merit (FOM) providing useful information for optimization of such pulse sequences. The first FOM (ΞAB) reports the efficiency of the desired total correlation spectroscopy transfer and should be as large as possible, while the second (ΞHet) reports the potential leakage of coherence to a heteronuclear spin and should be as small as possible.
Multipole hair of Schwarzschild-Tangherlini black holes
Authors: Fox Matthew S.
Published: October 2019

We study the field of an electric point charge that is slowly lowered into an n + 1 dimensional Schwarzschild-Tangherlini black hole. We find that if n > 3, then countably infinite nonzero multipole moments manifest to observers outside the event horizon as the charge falls in. This suggests the final state of the black hole is not characterized by a Reissner-Nordström-Tangherlini geometry. Instead, for odd n, the final state either possesses a degenerate horizon, undergoes a discontinuous topological transformation during the infall of the charge, or both. For even n, the final state is not guaranteed to be asymptotically flat.

The author of the article agrees to the retraction of the article effective May 5, 2021.
Accelerating equilibrium isotope effect calculations. II. Stochastic implementation of direct estimators
Authors: Karandashev Konstantin , Vaníček Jiří
Published: October 2019

Path integral calculations of equilibrium isotope effects and isotopic fractionation are expensive due to the presence of path integral discretization errors, statistical errors, and thermodynamic integration errors. Whereas the discretization errors can be reduced by high-order factorization of the path integral and statistical errors by using centroid virial estimators, two recent papers proposed alternative ways to completely remove the thermodynamic integration errors: Cheng and Ceriotti [J. Chem. Phys. 141, 244112 (2015)] employed a variant of free-energy perturbation called “direct estimators,” while Karandashev and Vaníček [J. Chem. Phys. 143, 194104 (2017)] combined the thermodynamic integration with a stochastic change of mass and piecewise-linear umbrella biasing potential. Here, we combine the former approach with the stochastic change in mass in order to decrease its statistical errors when applied to larger isotope effects and perform a thorough comparison of different methods by computing isotope effects first on a harmonic model and then on methane and methanium, where we evaluate all isotope effects of the form CH4−xDx/CH4 and CH5−xDx+/CH5+, respectively. We discuss the reasons for a surprising behavior of the original method of direct estimators, which performed well for a much larger range of isotope effects than what had been expected previously, as well as some implications of our work for the more general problem of free energy difference calculations.
Description of intermolecular charge transfer with subsystem density-functional theory
Authors: Schulz Anika , Jacob Christoph R.
Published: October 2019

Efficient quantum-chemical methods that are able to describe intermolecular charge transfer are crucial for modeling organic semiconductors. However, the correct description of intermolecular charge transfer with density-functional theory (DFT) is hampered by the fractional charge error of approximate exchange-correlation (xc) functionals. Here, we investigate the charge transfer induced by an external electric field in a tetrathiafulvalene–tetracyanoquinodimethane (TTF–TCNQ) complex as a test case. For this seemingly simple model system, a supermolecular DFT treatment fails with most conventional xc functionals. Here, we present an extension of subsystem DFT to subsystems with a fractional number of electrons. We show that within such a framework, it becomes possible to overcome the fractional charge error by enforcing the correct dependence of each subsystem’s total energy on the subsystem’s fractional charge. Such a subsystem DFT approach allows for a correct description of the intermolecular charge transfer in the TTF–TCNQ model complex. The approach presented here can be generalized to larger molecular aggregates and will thus allow for modeling organic semiconductor materials accurately and efficiently.
Reproductive dynamics, age and growth of Astyanax aff. fasciatus in a Neotropical basin
Authors: Silveira Estevan L. , Aranha José M. R. , Menezes Márcia S. , Vaz-dos-Santos André M.
Published: October 2019

Population dynamics provide crucial information for management and conservation. This study analysed the spatial and temporal patterns in reproductive biology, age and growth of Astyanax aff. fasciatus from a Neotropical river. Although located in a priority area for conservation, this river is affected by human activities in the surrounding landscapes. Water and environmental parameters were subjected to principal component analysis (PCA) to characterise the different sampling sites. Length–frequency distributions, gonad development and body indices were used to evaluate maturity and spawning, and to calibrate the von Bertalanffy model to determine the age and growth of A. aff. fasciatus. Reproductive behaviour of the species was not homogeneous along the river, due to geomorphology and human activities in the surrounding areas, with some sites becoming unavailable for breeding. The PCA highlighted the geomorphological, human (first axis) and temporal (second axis) trends influencing the environmental features along the river. Females predominated throughout the basin, and spawning took place from September to June in distinct areas of the river. The species matures at an age of 1–1.5 years, and so tends to be a fast-growing species, with a life span close to 3.5 years. Fish population dynamics should be monitored to support conservation and management, both for the fish species and the aquatic environments.
Characterization of argon plasma in a variable multi-pole line cusp magnetic field configuration
Authors: Patel A D , Sharma M , Ramasubramanian N , Ghosh J , Chattopadhyay P K
Published: October 2019

This paper presents a detail characterization of argon plasma confined by a multi-pole line cusp magnetic field (MMF) over a large cylindrical volume (1 m axial length and 40 cm diameter) (Patel et al 2018 Rev. Sci. Instrum. 89 043510) and various magnetic field scaling with magnet current obtained from the magnetic field simulation in the vacuum. From the experimental results, it has been observed that in this field configuration the confinement of the primary electrons increases and leak width (plasma escaping through the cusp) of plasma decreases with increasing the magnetic field. As a result the mean density, particle confinement time and the stability of the plasma increase with increasing magnetic field values. In addition to this, it has been also observed that the radial uniformity of the plasma density across the magnetic field explicitly depends on the magnetic field values of MMF. Moreover, the nature of turbulence in a quiescent argon plasma has been identified.
Comparative analysis on access and egress distances for Semi BRT Trans ‘Mamminasata’ and Commuter Train ‘SUSI’
Authors: Susanti A , Soemitro R A A , Suprayitno H
Published: October 2019

The existence of the Semi Bus Rapid Transit (BRT) Network and the Commuter Train Network, as part of Urban Mass Transportation is developed with the aim of providing better service on commuter trips. To estimate passenger demands on new mass transit services, especially in areas without prior service, Access and Egress distances data are needed to design an appropriate mass transit. This underlies the reason why a comparative analysis of Access and Egress distance of BRT Trans ‘Mamminasata’ in Makassar and Commuter Train Surabaya – Sidoarjo was necessarily done. Which of the two had further Access or Egress distance; was it the BRT Trans ‘Mamminasata’ Makassar or the Commuter train Surabaya-Sidoarjo? Data were obtained through interviews and data management from related department. The results found that both Access and Egress of the BRT Trans ‘Mamminasata’ in Makassar was shorter than the Commuter Train Surabaya-Sidoarjo.
Pedestrian exposure to Nitrogen Dioxide (NO2) and Carbon Monoxide (CO): A case study of Surabaya, Indonesia
Authors: Dewi B N , Syafei A D , Ciptaningayu T N
Published: October 2019

The increase in motor vehicles used every day also increases the rate of pollution. Motor vehicles are the main source of the nitrogen dioxide (NO2) and carbon monoxide (CO) pollutants that can be dangerous for human health in excessive amounts. This study investigates the patterns of NO2 and CO concentrations in the ambient air, specifically on the sidewalks of two big streets in Surabaya. Measurements were taken over a period of 15 hours using a portable monitoring device. The results indicated that the NO2 concentration would decrease by 0.008 mg/m3 and 0.012 mg/m3, respectively, at peak times during the day and night. Meanwhile, the CO concentration would increase by 1.486 mg/m3 during the peak time at night. The factors that significantly influenced NO2 were day variation (weekday or weekend), morning peak hour, noon peak hour, night peak hour, and temperature. Regression with these factors had an R2 value of 30.7%. For CO, the significant factors were night peak time, temperature, wind direction, and the number of vehicles, with an R2 value of 16.9%.
Priority study of infrastructure development at Suburban Pekanbaru (Case study: Tambang District)
Authors: Ismiyanti D , Asteriani F , Astuti P
Published: October 2019

The problems in the field of infrastructure are the main problems in the suburban of Pekanbaru, making it difficult to determine the priority of infrastructure development most needed by the community. The Analytical Hierarchy Process method and weighting of variables in priority setting are used in infrastructure development. The results of this study indicate that the average development of infrastructure is 20.75%. The priority of infrastructure development is road network (0.165), housing (0.095), educational facilities (0.089), economic facilities (0.086), health facilities (0.075), clean water (0.074), bridges (0.067), electricity grids (0.066) (0.059), telecommunication network (0.051), government facilities (0.049), garbage and drainage facilities (0.042), and sports facilities (0.041).
Economical valuation for measuring renewable energy efficiency as the implementation of smart city concept at Surabaya City
Authors: Umilia E , Santoso E B
Published: October 2019

Energy is the most important part of supporting human necessity. For this while, the crude oil energy which is mostly needed at Indonesia are fuel oil and electricity. Unfortunately, the domestic crude oil reserves are diminishing and global crude oil’s price has always fluctuated. Thus, the development of renewable energy is necessary. However, the alternative energy development in Indonesia still relies on fossil energy, which is not environmental friendly yet. Smart energy is one of the existed approaches in the concept implementation of smart city. Surabaya city has already had a number of innovations in smart energy implementation of alternative uses in utilizing renewable energy for particularly public services, such as solar cell, garbage power plant, and the application of wind turbine. Some of the mentioned alternative energy have been tried at government’s buildings, other government’s facilities, and public street lighting. There are some occurrences of problems such as the lack of readiness of the supporting facility, the energy production made a few trial project slowed down to be implemented. This study is trying to economically valuate about the efficiency level of renewable energies which have been tried. This study aims to offer an advantage of choosing the best alternative energy to be mass implemented. Thus, the smart city concept, especially smart energy, can be thoroughly implemented using the most efficient type of energy.
Problem identification of micro hydro power plant program in East Java Province
Authors: Kusuma S H , Aulia B U , Sardjito  , Farikha N
Published: October 2019

The availability of electricity is an important necessity in life to support the economic and social activities of the community such as industry, agriculture, household and trade. Without sufficient access to electricity, the goals of community economic and social development will not be achieved. One of the East Java Provincial Government’s efforts to meet its electricity needs is to build renewable energy sources such as micro-hydro power plants (or PLTMH in Indonesian) which are planned to be developed in 21 regencies or cities. However, until now the development of the PLTMH has not been implemented perfectly. Therefore, this research was conducted to determine the extent of the progress of the PLTMH development, factors that caused problems in the development of PLTMH, and recommendations for solving problems such as what could be formulated. The method used in this study is through qualitative descriptive analysis with indepth interview and using root cause analysis. Based on the results of this study it is known that the main thing that caused problems in the construction of the PLTMH was the existence of constraints in planning and financing. The recommendation for solving the problems obtained from this study is the need for technical planning and budgeting with financing schemes that can be sourced from the government or the private sector.
Analysis regarding modern market service level influence toward population movement patterns
Authors: Poerwati T , Imadiiddina A H , Putra Y A L
Published: October 2019

Modern market didn’t differ too much from traditional ones, but this kind of market exists within buildings and self-serving in nature. In terms of modern market services like Alfamart and Indomart, it can be said that the service provided is relatively stellar for it’s customers, whether it be the goods itself, the qualities of said goods, or the service system itself which includes home delivery. The purpose of this research is to find out the modern market service level influence toward population movement patterns. The research is done in Klojen District, Malang City. The analysis method used are qualitative descriptive method and Kendall’s Tau correlation method. Based on analysis result it’s concluded that minimarket service level didn’t quite affect population movement patterns due to it’s p-value which is 0,487 where the p-value is bigger than the significant value within this research which is 0,05. Population movement patterns were only influenced by type of goods needed (average of 61,7%), quantity of goods bought by the consumers, and price of goods (average of 29,3%).
Power loss prediction in asymmetric spur gear considering gear tooth dynamic load
Authors: Thomas Benny , Sankaranarayanasamy K , Ramachandra S , Suresh Kumar SP
Published: October 2019

In many gear drives, one side of the flank is subjected to relatively higher load for a longer duration than the other side. Asymmetric spur gears with drive side pressure angle higher than the coast side reflects this functional difference. Conventional design criteria and procedures followed for symmetric spur gears are suitably modified and applied to predict the gear tooth bending, contact stress and power loss in asymmetric spur gears. Quasi-static gear tooth load and empirical friction coefficient formulae were applied in the past to predict the sliding power loss in asymmetric spur gears. In the present work, Finite element method is used to determine the time varying mesh stiffness of the normal contact ratio asymmetric spur gear tooth. Computed gear tooth stiffness is used to predict the dynamic load at two different speeds under non-extended contact condition. Sliding power loss during the course of meshing is analytically calculated under quasi static and dynamic load conditions. Study demonstrates the difference in sliding power loss computed based on friction formulae and empirical friction coefficient formulae under static and dynamic load.
Degradation analysis of gear oil SAE 90 used in load haul dumper machine
Authors: Dewangan Nagesh , Agrawal Anil Kumar , Siddiqui Mohd A H , Chattopadhyaya Somnath
Published: October 2019

Lubricant degradation is the main cause for low performance of the machine such as heavy engineering machines, mining machinery etc. Lubricants are used for smooth running of gears and they also avoid friction and noise. Its performance is affected by high temperature and shearing, due to high temperature viscosity of oil changes and due to shearing its physical property changed or degraded. This paper analyses the failure behaviour of gear oil used in Load Haul Dumper (Model No: Eimco Elecon – 811MK). Gear oil degradation was measured by oil analysis in two sections: (i) fluid properties and (ii) contamination in the oil. Fluid properties were analysed by Viscometer, Rheometer whereas contamination analysis was done by Fourier Transform Infrared spectrometer (FTIR). All tests were performed carefully and their graphs were plotted. Results show that temperature and shearing were two of the several causes for degradation of oil. Viscosity analysis clearly presents that viscosity of oil exponentially decreases with temperature. Viscosity is also decreasing with shear rate at different temperatures. FTIR analysis confirmed that contamination is increasing with continuous use of oil. Temperature and oxidation are the main reasons for degradation. Different composition forming in used gear oil and those were confirmed by infrared spectroscopy absorption table.
Influence of Link Lengths & Input Angles on the Foot Locus Trajectory of Klann Mechanism
Authors: Prashanth N , Manoj R M , Nikhil B
Published: October 2019

Locomotive drive mechanisms for robots have been an active research area in the field mobile robotics. Several drive mechanisms such as wheeled, legged, hybrid & reconfigurable mechanisms have been extensively studied. The legged locomotive drive mechanism has several advantages to its credit & it is often bio-inspired. The disadvantage of legged locomotive drive mechanism in general is it is often considered as complex in design due to its multi degrees of freedom which requires complex control scheme. This has led roboticists to explore minimal legged locomotive drive mechanisms consisting of single degrees of freedom. The present work focuses on synthesis and analysis of one such planar mechanism such as klann mechanism for a mobile robot application. In this work, we have synthesized the various linkages of klann mechanism to find the optimal foot locus trajectory. The synthesis and analysis of mechanism is performed using SAM (Synthesis and analysis of mechanism) software. We have described influence of various parameters such linkage length and input crank angle on the foot locus. We have compared the foot locus trajectory for three different foot locus by performing the kinematic analysis. Various parameters such as position, velocity and acceleration of linkages are compared & illustrated in detail. The information provided in this work will help the roboticists to select appropriate link length for klann mechanism to obtain various foot locus designs. This information may be further used to design efficient legged locomotive drive mechanisms for various terrain conditions.
Evaluation of lubricant properties of vegetable oils as base oil for industrial lubricant
Authors: Sneha E , Rani S , Arif Muhammed
Published: October 2019

The possible insufficiency of oil resources in the future and the poor bio-degradability of mineral oil based lubricant resulted in the need of bio lubricant. Bio-based products are typically produced from vegetable oils. For the present study rice bran oil [RBO], jatropha oil [JO] and karanja oil [KO] are selected as the base oils for the industrial lubricant. Friction and wear characteristics are evaluated on four ball tester and the initial findings show that wear scar of RBO is lowest, this is because of the presence of natural anti-oxidants like gamma oryzanol. The coefficient of friction and wear of all the oils were evaluated as per ASTM D5183 and ASTMD 4172 respectively. Viscosity of the oils are tested on Brookfield rheometer and KO is having high viscosity when compared to other two oils but the change in viscosity with temperature is low for both RBO and JO. Chemical properties of the oils are conducted as per IS: 548 (Part 1) –1964. The iodine value for KO is less when compared to RBO and JO. Less iodine value is required to impart better oxidation stability. Thermogravimetric analysis showed that RBO is stable till 320 °C and KO, JO started degrading at 200 °C. The thermal properties of all the oils are measured and RBO has shown better properties at wide range of temperatures. The disadvantages of vegetable oils like oxidative stability need to be improved by adding additives and by chemical modifications.
Design optimization of steering knuckle by adopting bionic design approach
Authors: Ghungarde Vikas , Awachar Sudhir , Vaidya N K , Jagadeesha T
Published: October 2019

Weight optimization plays vital role in performance improvement for an automobile. In vehicle, steering knuckle is one of critical components as it is subjected to millions of varying cyclic loads and it contributes to unsprung mass of vehicle. Therefore, steering knuckle of passenger vehicle is selected for this research work. The aim of this research work is to relate optimized shape of the part with bionic shape, which will give the optimum design. Topology optimization is used as a tool for getting optimum material layout with given space and boundary conditions. The objective function for topology optimization is to maximize stiffness with minimum mass constraints as 30%. The optimization is done by Altair INSPIRE software in which the part is imported as cad model with SG 500/7 as part material. The final surface modeling is done by Polyworks software package for parametric model and result of that modelling has been applied for the standard analysis of the part. The proposed design of the parts meets the strength and stiffness as per requirement. For physical prototype the part is manufactured by additive manufacturing using AlSi10Mg as a material and required properties for same material is also generated. New proposed design of the part shows that there is reduction in weight by 35%.
Optimal Design and Analyses of T-shaped rotor Magnetorheological Brake
Authors: Acharya S , Saini T R S , Kumar H
Published: October 2019

Magnetorheological (MR) brakes, belonging to the class of electromagnetic brakes, have a potential to replace conventional hydraulic brakes owing to reversible, rapidly controllable torque characteristics. In this study, T-shaped rotor MR brake was considered due to their higher braking torque capability and compactness compared to other configurations of brake. Optimal design of the brake was performed considering brake rotor radius, rotor thickness, flange length, casing thickness, coil height and coil width. Magnetostatic analyses were performed for different combinations of parameters of the brake dimensions to compute the magnetic flux density generated in the MR fluid region and the torque ratio and mass were calculated. The optimum dimensions of the brake were determined based on maximization of torque ratio and minimization of mass of the brake using multi-objective Genetic algorithm optimization technique. Further, magnetostatic analyses of the T-rotor brake with optimal dimensions were performed and torque characteristics were compared with those obtained for brake with simple disk rotor. It was concluded that T-rotor brake produces higher braking torque compared to simple disk rotor type MR brake for similar dimensions.
Impurity effects on nano-structured dirty superconductors: violation of Anderson’s Theorem
Authors: Umeda Masaki , Kato Masaru
Published: October 2019

It is shown that in nano-structured s-wave superconductor, transition temperature T

c
depends on random impurity potentials. This means violation of the Anderson’s theorem, which states that non-magnetic impurity does not affect the T

c
of s-wave superconductor. We determine the impurity effects on T

c
for nano-structured superconductor, using the finite element method to solve the Bogoliubov-de Gennes equations under spatially a random impurity potential. We show that some impurity potentials increase T

c
but other impurity potentials decrease T

c
. We find that the superconductor with localized order parameter shows increased T

c
, which is contrary to expectation. Our results show that a dirty superconductor does not always mean weak superconductivity.
Beyond the isotropic Lifshitz endpoint
Authors: Chang Tom T S
Published: October 2019

The puzzle of the disappearance of isotropic Lifshitz points in condensed matter physics is explained from the point of view of the Wilsonian renormalization group. In analogy to the commensurate ideas of metamagnetic phase transitions, we describe the physics of thermodynamic states beyond an isotropic Lifshitz endpoint. Such phenomenon may be understood in terms of a statistically isotropic environment of coexisting multiple helicoidal and non-helicoidal states. In addition to the magnetic and condensed matter discussions, we consider also an interesting example in the context of cosmic evolution.
The interaction between grain boundary and tool geometry in nanocutting of a bi-crystal copper
Authors: Wang Zhanfeng , Sun Tao , Zhang Haijun , Li Guo , Li Zengqiang , Zhang Junjie , Yan Yongda , Hartmaier Alexander
Published: October 2019

Anisotropy is one central influencing factor on achievable ultimate machined surface integrity of metallic materials. Specifically, grain boundary has a strong impact on the deformation behaviour of polycrystalline materials and correlated material removal at the microscale. In the present work, we perform molecular dynamics simulations and experiments to elucidate the underlying grain boundary-associated mechanisms and their correlations with machining results of a bi-crystal Cu under nanocutting using a Berkovich tool. Specifically, crystallographic orientations of simulated bi-crystal Cu with a misorientation angle of 44.1° are derived from electron backscatter diffraction characterization of utilized polycrystalline copper specimen. Simulation results reveal that blocking of dislocation motion at grain boundaries, absorption of dislocations by grain boundaries and dislocation nucleation from grain boundaries are operating deformation modes in nanocutting of the bi-crystal Cu. Furthermore, heterogeneous grain boundary-associated mechanisms in neighbouring grains lead to strong anisotropic machining behaviour in the vicinity of the grain boundary. Simulated machined surface morphology and machining force evolution in the vicinity of grain boundary qualitatively agree well with experimental results. It is also found that the geometry of Berkovich tool has a strong impact on grain boundary-associated mechanisms and resultant ploughing-induced surface pile-up phenomenon.
Impact of an extended International Normalized Ratio follow-up interval on healthcare use among veteran patients on stable warfarin doses
Authors: Margolis Amanda R , Porter Andrea L , Staresinic Carla E , Ray Cheryl A
Published: October 2019

Purpose

To analyze the impact of a 12-week extended International Normalized Ratio (INR) follow-up interval on healthcare use.

Methods

A prospective cohort study of the use of an extended INR follow-up interval of up to 12 weeks was conducted over 2 years in a pharmacist-managed anticoagulation clinic. A detailed protocol was used to extend the INR follow-up interval to 5–6 weeks and then 7–8 weeks and 11–12 weeks. The number of planned and unplanned anticoagulation encounters, procedures requiring warfarin interruption, telephone triage phone calls, emergency department visits, and hospitalizations were collected. A post hoc subanalysis was also completed on participants who were scheduled for 4 consecutive 12-week intervals.

Results

Compared to baseline, at 12 months there was a mean decrease in planned anticoagulation encounters of 2.24 visits (p < 0.001) among 44 participants. From 12 to 24 months compared to baseline, there was a mean decrease in planned anticoagulation encounters of 3.13 visits (p < 0.001) and an increase of 0.54 unplanned anticoagulation encounters (p = 0.04) among 39 participants. The remainder of healthcare use variables were not statistically significantly different from baseline at any time point. Of the 15 participants scheduled for 4 consecutive 12-week intervals, there was a decrease from baseline of approximately 5 visits over the course of a year (p < 0.001).

Conclusion

An extended INR follow-up interval appears to decrease anticoagulation healthcare use without an increase in acute healthcare use. While this intervention could be cost-effective, institutions need to consider safety, efficacy, and feasibility prior to implementation.
On the Green function of the Lord–Shulman thermoelasticity equations
Authors: Wang Zhi-Wei , Fu Li-Yun , Wei Jia , Hou Wanting , Ba Jing , Carcione José M
Published: October 2019

Thermoelasticity extends the classical elastic theory by coupling the fields of particle displacement and temperature. The classical theory of thermoelasticity, based on a parabolic-type heat-conduction equation, is characteristic of an unphysical behaviour of thermoelastic waves with discontinuities and infinite velocities as a function of frequency. A better physical system of equations incorporates a relaxation term into the heat equation; the equations predict three propagation modes, namely, a fast P wave (E wave), a slow thermal P wave (T wave), and a shear wave (S wave). We formulate a second-order tensor Green's function based on the Fourier transform of the thermodynamic equations. It is the displacement–temperature solution to a point (elastic or heat) source. The snapshots, obtained with the derived second-order tensor Green's function, show that the elastic and thermal P modes are dispersive and lossy, which is confirmed by a plane-wave analysis. These modes have similar characteristics of the fast and slow P waves of poroelasticity. Particularly, the thermal mode is diffusive at low thermal conductivities and becomes wave-like for high thermal conductivities.
Methane production and nitrogen balance of dairy heifers grazing palisade grass cv. Marandu alone or with forage peanut
Authors: Berça Andressa S , Cardoso Abmael Da S , Longhini Vanessa Z , Tedeschi Luís O , Boddey Robert Michael , Berndt Alexandre , Reis Ricardo A , Ruggieri Ana Cláudia
Published: October 2019

Livestock production systems are an essential agribusiness activity in Brazil, but a critical challenge of Brazilian farmers is to maintain the equilibrium of the ecosystem, using herbage resources efficiently with a minimum impact on the environment. Nitrogen (N) fertilization and the inclusion of forage legumes into tropical grass pastures are management strategies which increase the productivity and nutritive value of pastures and may also affect methane (CH4) production by ruminants. The objective of this study was to examine the effects of either fertilizing palisade grass pastures with N or including the forage peanut (Arachis pintoi) into grass pastures on enteric CH4 emission, microbial protein production in the rumen via purine derivatives in the urine, and N balance. Twenty-one nonlactating crossbred dairy heifers were used in a completely randomized design with 3 treatments. The treatments consisted of pastures of palisade grass without N fertilization (control), fertilized with urea (fertilized), and palisade grass mixed with forage peanut (mixed). Seven animals (replications) were used to evaluate dry matter intake, digestibility, CH4 emission, urea, purine derivatives, and volume of urine, and N ingestion and excretion. Four paddocks (replications) were used to measure herbage mass; morphological, botanical, and chemical composition of herbage; and herbage allowance. The CH4 emissions were determined using the sulfur hexafluoride (SF6) tracer gas technique. The efficiency of N utilization (ENU) was calculated using the N balance data. Crude protein (CP) concentration of herbage increased with fertilization or legumes inclusion (P < 0.0001) while neutral detergent fiber (NDF) concentration decreased (P = 0.0355). The leaf allowance was higher in the fertilized treatment (P = 0.0294). Only uric acid excretion increased with N fertilization (P = 0.0204). The ENU was not affected by fertilized or mixed compared to control and averaged 55% (P = 0.8945). The enteric CH4 production was similar between treatments and averaged 129 g/d (P = 0.3989). We concluded that the changes in chemical composition of herbage provided by N fertilization or the inclusion of the legume showed no reduction in enteric CH4 emissions, but the ENU was more significant than previous studies with palisade grass, suggesting that different management strategies might alter the ENU under grazing conditions.
Mapping the Potential Distribution of Oak Wilt (Bretziella fagacearum) in East Central and Southeast Minnesota Using Maxent
Authors: Gearman Melissa , Blinnikov Mikhail S
Published: October 2019

With the advancement of spatial analysis and remote sensing technology, potentially devastating forest pathogens can be managed through spatial modeling. This study used Maxent, a presence-only species-distribution model, to map the potential probability distribution of the invasive forest pathogen oak wilt (Bretziella fagacearum) in eastern and southeastern Minnesota. The model related oak wilt occurrence data to environmental variables including climate, topography, land cover, soil, and population density. Results showed that areas with the highest probability of oak wilt occur within and surrounding the Minneapolis/St. Paul metropolitan area. The jackknife test of variable importance indicated land cover and soil type as important variables contributing to the prediction of the distribution. Multiple methods of analysis showed that the model performed better than random at predicting the occurrence of oak wilt. This study shows Maxent’s potential as an accurate tool in the early detection and management of forest diseases.