bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of a flat‐type magnetic position sensor using a finite‐difference method
Authors: Mirzaei Mehran , Machac Jan , Ripka Pavel , Chirtsov Andrey , Vyhnanek Jan , Grim Vaclav 
Published: January 2020

This study presents an analysis and the design of a new flat‐type position sensor with an external armature. One excitation coil and two antiserially connected pickup coils are used in the stationary part. Solid iron segments or steel lamination segments are used for the moving armature. The proposed position sensor was modelled using linear movement. A two‐dimensional finite‐difference method was developed and was used for fast analysis for optimising the sensor. The induced eddy currents in the solid armature were taken into account in the finite‐difference analysis. The finite‐difference calculations were compared with 2D and 3D finite‐element method simulations and with experimental results. The sensor has a total error of 0.23 mm root‐mean‐square for 36 mm range without any compensation. Unlike previous designs, the authors’ new sensor has no moving coil.
HCN-to-HNC intensity ratio: a new chemical thermometer for the molecular ISM
Authors: Hacar A. , Bosman A. D. , van Dishoeck E. F. 
Published: January 2020

Context. The gas kinetic temperature (TK) determines the physical and chemical evolution of the interstellar medium (ISM). However, obtaining reliable TK estimates usually requires expensive observations including the combination of multi-line analysis and dedicated radiative transfer calculations.
Aims. This work explores the use of HCN and HNC observations, and particularly the I(HCN)-to-I(HNC) intensity ratio (I(HCN)/I(HNC)) of their J = 1–0 lines, as direct probe of the gas kinetic temperature in the molecular ISM.
Methods. We obtained a new set of large-scale observations of the HCN and HNC (1–0) lines throughout the Integral Shape Filament (ISF) in Orion. In combination with ancillary gas and dust temperature measurements, we find a systematic temperature dependence of the observed I(HCN)-to-I(HNC) intensity ratio throughout our maps. Additional comparisons with chemical models demonstrate that these observed I(HCN)/I(HNC) variations are driven by the effective destruction and isomerization mechanisms of HNC under low-energy barriers.
Results. The observed variations of I(HCN)/I(HNC) with TK can be described with a two-part linear function. This empirical calibration is then used to create a temperature map of the entire ISF. Comparisons with similar dust temperature measurements in this cloud, as well as in other regions and galactic surveys, validate this simple technique for obtaining direct estimates of the gas kinetic temperature in a wide range of physical conditions and scales with an optimal working range between 15 K ≲ TK ≤ 40 K.
Conclusions. Both observations and models demonstrate the strong sensitivity of the I(HCN)/I(HNC) ratio to the gas kinetic temperature. Since these lines are easily obtained in observations of local and extragalactic sources, our results highlight the potential use of this observable as new chemical thermometer for the ISM.
Organic-Photoacid-Catalyzed Glycosylation
Authors: Wang Ting , Li Juncheng , Zhao Gaoyuan 
Published: January 2020

Photoacids are molecules that become more acidic upon absorption of light. They are widely utilized in a variety of fields, such as organic synthesis, molecular switching agents, and photodynamic therapy. Currently, the activity of most photoacids is induced by UV light, which limits their applications by the synthetic community. In this ­Synpacts article, we highlight our recent development of visible-light-­induced photoacids and their application in glycosylation reactions.1	Introduction2	Visible-Light-Induced Photoacids3	Synthesis of 2-Deoxyglycosides by Visible-Light-Induced Photoacid Catalysis4	Conclusion
β-lactolin, a whey-derived glycine―threonine―tryptophan―tyrosine lactotetrapeptide, improves prefrontal cortex-associated reversal learning in mice
Authors: Ayabe Tatsuhiro , Ohya Rena , Ano Yasuhisa 
Published: January 2020

Abstract
Dementia and cognitive decline have become worldwide public health problems. We have previously reported that a whey-derived glycine―threonine―tryptophan―tyrosine peptide, β-lactolin, improves hippocampus-dependent memory functions in mice. The supplementation with a whey digest rich in β-lactolin improves memory retrieval and executive function in a clinical trial, but the effect of β-lactolin on prefrontal cortex (PFC)-associated cognitive function was unclear. Here we examined the effect of β-lactolin and the whey digest on PFC-associated visual discrimination (VD) and reversal discrimination (RD) learning, using a rodent touch panel-based operant system. β-Lactolin and the whey digest significantly improved the RD learning, and the whey digest enhanced the response latency during the VD task, indicating that β-lactolin and the whey digest improve PFC-associated cognitive functions. Given the translational advantages of the touch panel operant system, consumption of β-lactolin in daily life could be beneficial for improving human PFC-associated cognitive function, helping to prevent dementia.
Molecular identification of white root fungal pathogens and in vitro effect of nanopesticide
Authors: Noveriza R , Rahajoeningsih S , Harni R , Miftakhurohmah  
Published: January 2020

Abstract
White root is an important disease in plantation crops such as rubber, cashew, clove, coffee, and nutmeg. This study aims to molecularly identify white root fungi isolated from white root disease of rubber and nutmeg plants and in vitro effect of nano formulated citronella and clove oils to the fungi. Few fungi isolated from the rubber and nutmeg plants were identified using 4 pairs of universal primers. Effect of nano-pesticide citronella and clove oils was evaluated in invitro against mycelial growth of white root fungi isolates (K1 and P1). The result showed that DNA of the fungi was successfully extracted from fungi isolated from nutmeg and rubber plants using 4 pairs of universal primers. K1 and P1 isolates were identic to Marasmius palmivora (99.1%) and K2 was closed to Rigidoporus microsporus (97.5%), while KP isolates could not be identified because the DNA was contaminated with Trichoderma harzianum. Nanoformulation of citronella and clove oils at 0.5% concentration inhibited mycelial growth of M. palmivorus isolated from rubber and nutmeg plants. The study implies that nano formulation of clove and citronella oils are potential to be tested at green house scale and then in the field for controlling the white root fungal pathogen.
Sustainability design for development of Gayo’s Science Park’s
Authors: Jaya R , Ferizal M , Ardiansyah R , Husaini  , Mirza I , Ishar  , Asis  , Ismail M , Rahmah F F F , Yusriana  
Published: January 2020

Abstract
Development of the Gayo’s Science Park’s (GSPs) aims to improve the regional economy based on commodity Gayo coffee. Sustainability aspect assessed including technique, economic, social as well as ecology. The objective of this paper was to design the sustainability development of the (GSPs). In this paper we only limits on qualitative judgment of the GSPs development design. In technical aspect discusses how to increase productivity Gayo coffee which currently ranges 650-700 kg ha−1, even though the potential productivity reaches 1.2-1.5 ton ha−1. For the economic aspect focuses on how the GSPs continuing coffee-based production down-stream. In this design also discussed the ecological, technical and social aspects such as increasing productivity, use of organic matter on agriculture as well in plants cultivation conservation zone. To sustain the GSPs, we design a business that will be developed, namely through construct the small-plants (5 kg per running production) and Gayo coffee superior seeds supplier. Therefore, we use several techniques to construct its planning, such as business plan canvas and qualitative SWOT analysis, as well as introducing the innovative technology and site-plan.
Abrasive flow modelling through active parts water jet machine using CFD simulation
Authors: Pătîrnac I , Ripeanu R G , Laudacescu E 
Published: January 2020

Abstract
This study has the main objective the flow modelling using CFD through active parts waterjet cutting machine, model YCWJ-380-1520. More precisely, the study of flow through the cutting head and estimate the erosion wear caused by abrasion of these parts. The active parts of cutting head are the body of head, high pressure nozzle with jewel and mixing tube made from wolfram carbide. On all these components has previously done measurement in order to create the geometrical model. The most wearing subjected parts water-jet machine are the water nozzle and mixing tube where the erosion wear is accelerated by the high velocity. In the first part of this study is presented the water flow model without regarding the abrasive inlet geometry, using Ansys FLOTRAN CFD. Has been considered three dimensions of water nozzle along with three dimensions of mixing tube in order to evaluate velocity variation at mixing tube outlet and how geometry influences outlet velocity. The second part of this paper is made using CFD software Ansys Fluent regarding a tridimensional geometry and a multiphasic flow. In the framework of flow model is established the abrasive particles velocity, difference of pressure inside tube, contour of streamlines, shear stress on the tube wall in order to accomplish the erosion rate during the process flow. It can be noticed that there are two main streamlines: first at the outlet of water nozzle and second from the inlet of abrasive material. Particles velocity is higher at the contact with water stream and lower at the end of cutting head because the difference of diameters between jewel and mixing tube. The maximum erosion rate is recorded where the shear stress are high values, that means to the interior wall of water nozzle and inlet of mixing tube. Pressure becomes high to the jewel of water nozzle and decreases in value toward at outlet of cutting head.
Research on mechanical and geometrical characteristics of materials used for flexible tubing production
Authors: Hagianu A , Nae I , Ionescu G C , Ripeanu R G 
Published: January 2020

Abstract
Coiled tubing used in operational exploitation of oil and gas wells are made of special steels which have to resists to some special requirements such as: tensile strength, internal pressure resistance, collapsing resistance, fatigue strength, corrosion resistance and action of weakening factors. It is interesting that various producers are using different compositions of their steels obtaining quite different mechanical characteristics of the flexible tubing delivered on the market. This paper is presenting the experimental programme for mechanical tests conducted on materials used for production of flexible tubing and the results obtained during these tests. In addition to the materials testing there were studied geometrical characteristics of the flexible tubing such as wall thickness, ovality, cilindricity and their impact on operational life of the flexible tubing.
Experimental Determination of the Loading Capacity of the Elastic Bracelet Assembly
Authors: Geonea I , Dumitru N , Copilusi C , Margine A 
Published: January 2020

Abstract
In this paper we aim to experimentally determine the bearing capacity (the momentum) of the elastic bracelet assemblies. The moment of torsion transmitted by the assembly depends on the clamping force of the assembly and on the friction coefficient between the bushing mounted on the shaft and the hub of the assembly. An experimental stand is used which comprises a hub shaft assembly with a segmented elastic bracelet. The load bearing capacity of the elastic bracelet is determined depending on the strength of the screws. Experimental determination is made on three types of materials. For this purpose, on the shaft is assembled a bush made of different materials: aluminum, bronze, steel. In order to determine the capable assembly moment, strain gauge transducers are used to measure the elastic strains. The recording of the deformations is done by means of an efficient data acquisition system. The assembly characteristic is plotted, namely the dependence between the torque transmitted according to the tightening of the bolts, for three couples of materials.
Power loss in grease lubricated ball bearings
Authors: Ianuş G , Cojocaru D , Oprişan M C , Paleu V , Olaru D N 
Published: January 2020

Abstract
The authors theoretically investigated and then validated the power loss generated both by sliding and rolling in a modified thrust ball bearing with 3 balls operating at low axial load and grease lubrication. Based on ball forces and moment equilibrium, it has been determined the tangential forces on contact ellipses. The hydrodynamic rolling friction forces have been determined by using Biboulet & Houpert’s methodology considering base oil viscosity of the grease. Total power loss has been obtained as a sum of two components: power loss generated by sliding and power loss generated by rolling. Also, total friction torque has been theoretically determined and, as an alternative method, the total power loss has been calculated as a product between total friction torque and angular speed. Finally, based on previously experimental results, the power loss has been validated as the product between experimentally total friction torque and angular speed. A good correlation between the power losses determined by all three methods for 100, 200, 300 and 400 rpm have been obtained.
Abrasive and Erosion Wear of Composite NiCrSiB Coatings Inflicted with Subsonic Flammable Structure through a Cold Process
Authors: Kandeva M , Penyashki T , Kostadinov G , Kalichin Zh 
Published: January 2020

Abstract
Ni-Cr-B-Si alloys are commonly used in the thermal spraying of steels. Despite their widespread use, their role in protecting metal surfaces from wear is not yet fully clarified. In order to obtain data and understanding of the wear and wear resistance of these coatings, the present work is studied the characteristics of the abrasive and erosive wear of new Ni-Cr-B-Si composite coatings applied by means of a sonic flame jet when heating the substrate to 180 °C (cold process). The powdered compositions used contain particles with an average size of 40 µm and a different percentage of the chemical elements. The abrasion wear is investigated using the thumb-disc pattern for dry surface friction with rigidly attached abrasive particles. Erosion wear is investigated by the interaction of air-jet coatings carrying abrasion particles. All samples in abrasion and erosion are tested under the same contact conditions. The mechanism, speed, and intensity of wear, and wear resistance of coatings at different normal load and slip speeds were obtained.
Tribological behaviour of sealing materials
Authors: Birleanu C , Pustan M , Cosma C , Merie V , Dranda O 
Published: January 2020

Abstract
The sealing elements are the most critical part of the mechanical sealing assembly and the main aspects of these are the tribological ones. The structural behaviour of the sealing components plays a crucial role in determining the sealing performance. Wide varieties of materials are used as seal face materials in practice. In this paper we focus on a couple of sealing materials CoCrWMo alloy / four different types of materials (copper-zinc alloy – brass, tin-copper alloy-bronze, graphite bronze and Teflon – PTFE). Dry and lubricant friction and ring on ring configuration are considered using a ring on ring tribometer. The rings from CoCrWMo alloy were additive manufactured using selective laser melting (SLM) process. Tribological tests were run at room temperature on different couples. These materials present different tribological behaviours in terms of sliding wear evaluation.
Evaluation of stress risers severity in spur gears meshing
Authors: Creţu Spiridon S 
Published: January 2020

Abstract
The standards for gears design use the maximum value of the normal stress σ
zz
, depicted σH, as critical stress for RCF of gears. This value σH can’t sustain evidences regarding the stress risers influences. The paper uses the von Mises stress σvM as critical stress responsible for the initiation of RCF. For concentrated contacts analyses the drawback of FEM is the very long computing time and therefore the author used a semi-analytical method (SAM) based on the numerical formulation for the involved equations of linear half-space theory. The finite width of gears’ teeth imposes quarter-space limitations and consequently the virtual pressures and correction coefficient were considered in the iterative process for pressures distribution. The pressure distribution was further used to evaluate the stress tensor components and 3D distributions of von Mises stresses. Examples are presented for spur gears with different values for end chamfers.
The Fretting Contact of Coated Bodies. Part I – Contact Parameters
Authors: Spinu S , Cerlinca D 
Published: January 2020

Abstract
In case of a mismatch between the elastic properties of the contacting bodies, the solution of the fretting contact can only be achieved numerically due to the connection between the contact pressure and the shear tractions. The numerical treatment of the contact processes employs an iterative strategy, and therefore requires the computation of the displacement response of the elastic body, assumed as an elastic half-space, subjected to general loadings. Unlike the case of homogeneous bodies with known Green’s functions, a closed-form expression of the response of layered semi-infinite solids to unit point loads has only been attained in the frequency domain. The latter formulas are used in this paper to assess the displacement due to arbitrary normal and shear surface tractions, thus empowering the application of a trial-and-error approach in finding the parameters of a fretting contact: the contact area, the slip and the stick regions, and the distributions of pressure and shear tractions. The contact parameters are assessed in a nested loop strategy, involving three levels of iterations. The inner level, based on the conjugate gradient method for linear systems of equations, finds the pressure when solving the contact problem along the normal direction, disconnected from any tangential effects, or the shear tractions when considering the contact equations in the tangential direction, disconnected from the pressure influence. The middle level stabilizes the pressure with respect to the shear tractions, thus assuring that the global instantaneous contact solution is achieved. The outer level manages the reproduction of the loading history in a fretting loop, by load incrementation. The proposed strategy proves itself as a robust tool for the prediction of the fretting contact process involving coatings.
The Fretting Contact of Coated Bodies. Part II – The Stress State
Authors: Spinu S , Cerlinca D 
Published: January 2020

Abstract
The service life of contacting coated machine elements is ultimately determined by the distribution of stresses in the coating and in the substrate. By assuming the elastic bodies as elastic half-spaces, the contact stress computation entails the calculation of convolutions expressing the superposition of effects of unit point loads acting on the boundary. The fundamental solutions of stresses and displacements in multilayered materials have only been calculated in the frequency domain, and are known as the frequency response functions. An additional difficulty arises in the stress calculation, related to frequency response function valuation in the origin of the frequency domain, where a singularity is usually encountered. This case of un-determination is circumvented in this paper by substituting the required value with the mean value of the frequency response function over a vicinity centered in origin. The latter approach is endorsed by the fact that the frequency response function is singular, but numerically integrable in the aforementioned vicinity. The latter technique is validated by comparison with results obtained for the sliding contact, and then applied to derive the elastic stresses arising during a fretting loop in the coating and in the substrate. The stresses due to shear tractions are superimposed to those induced by contact pressure. The calculation is performed in layers of constant depth, and the algorithmic complexity is optimized by using state-of-the-art techniques for discrete convolution computation. The equivalent stress is discontinuous across interface between the two layers, and the location and intensity of the maximum von Mises stress is determined by the frictional coefficient and by the mismatch between the Young moduli of the coating and the substrate. The results obtained with the newly proposed numerical technique may extend the understanding of the fretting contact of coated materials and assist the design of improved coating configurations.
A study of the crack initiation angle in the substrate of spur gear teeth subjected to rolling contact fatigue
Authors: Popa C O 
Published: January 2020

Abstract
Fracture failure of engineering structures is caused by cracks that extend beyond a safe size. For modeling the stable fatigue crack propagation it is necessary to determine the angle of crack initiation, i. e. the angle under the crack growth takes place. There are several criteria that try to model this aspect, such as: Sih, MTS, M, T, Ip.
The S-criterion (Sih) was used to simulate the fatigue growth of an internal crack situated in the substrate of a certain spur gear, taking into account the rolling contact fatigue. S-criterion states that the direction of crack initiation coincides with the direction of minimum strain energy density along a constant radius around the crack tip. Since the stress intensity factor Ki is negligible (because of the compression stresses in the substrate of the gear tooth), calculations were made for these conditions and it was obtained a constant and unique angle of crack initiation angle 9 ∼ 80°, that is in concordance with the experimental observations. This study serves to determine the fatigue crack initiation angle in a compression stresses field, as well as its use in modeling the propagation of the fatigue cracks.
Considerations regarding determination of optimal preventive maintenance periodicity for subsurface sucker rod pumps
Authors: Drumeanu A C 
Published: January 2020

Abstract
The subsurface sucker rod pumps are important equipment used for the secondary oil recovery. In their structure, there are friction couples, which are strongly subjected at wear like barrel-plunger, traveling valve and standing valve. The operating durability of subsurface sucker rod pumps is practically determined by the reliability of these couples depending on the work conditions.
The paper presents a case study on the optimization of preventive maintenance of the subsurface sucker rod pumps. The optimal periodicity, of the preventive maintenance of the above mentioned friction couples, is determined on the basis of their operating reliability. There were analyzed two types of preventive maintenance, at fixed time, and at fixed age respectively. The paper results are embodied in practical charts which can be used for choosing optimal preventive maintenance period of the subsurface sucker rod pumps.