bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and electrochemical properties of nanocrystalline diamond and graphene hybridized films
Authors: Jiang M. Y. , Ma W. C. , Han S. J. , Chen C. K. , Fan D. , Li X. , Hu X. J.
Published: January 2020

We have successfully grown a series of nanocrystalline diamond and graphene hybridized (NCD-G) films with various morphologies and compositions of grain boundaries by adjusting the growth pressure by hot-filament chemical vapor deposition and extensively investigated their electrochemical performances. In the case of low growth pressure, such as 1.0 and 1.3 kPa, there is a large amount of graphene in the NCD-G films, and graphene exhibits better crystallinity and a bigger size. These produce quicker electron exchange, rising background current, and reduced potential window. As the growth pressure increases to above 1.6 kPa, the grain boundaries are reduced, so that the NCD-G films possess fewer graphene components. As the growth pressure is 1.6 kPa, the “bridge”-like graphene stands on the neighboring nanocrystalline diamond grains, providing degraded electrochemical properties of smaller redox current. With the growth pressure further increasing to 1.9 kPa, the least trans-polyacetylene wrapped diamond grains produce slightly rising redox current, wider potential windows, and smaller background current. Graphene exists as a small slice and is distributed parallel with the grains with the growth pressure increasing to 2.2 kPa, exhibiting a significant rising redox current accompanied with wider potential windows and lower background current. It is concluded that the high diamond content is beneficial to enlarge the potential windows and decrease the background current, and the graphene components take advantage of improving the redox current. Moreover, the ordered and small graphene surrounding the diamond grains is positive to improve the electrochemical response without the rising background current. Thus, we prepare an electrochemical electrode material with excellent performance by adjusting the state and the content of each component in the NCD-G films.
Monolayer GaN excitonic deep ultraviolet light emitting diodes
Authors: Wu Y. , Liu X. , Wang P. , Laleyan D. A. , Sun K. , Sun Y. , Ahn C. , Kira M. , Kioupakis E. , Mi Z.
Published: January 2020

We report on the molecular beam epitaxy and characterization of monolayer GaN embedded in N-polar AlN nanowire structures. Deep ultraviolet emission from 4.85 to 5.25 eV is measured by varying the AlN barrier thickness. Detailed optical measurements and direct correlation with first-principles calculations based on density functional and many-body perturbation theory suggest that charge carrier recombination occurs predominantly via excitons in the extremely confined monolayer GaN/AlN heterostructures, with exciton binding energy exceeding 200 meV. We have further demonstrated deep ultraviolet light-emitting diodes (LEDs) with the incorporation of single and double monolayer GaN, which operate at 238 and 270 nm, respectively. These unique deep ultraviolet LEDs exhibit highly stable emission and a small turn-on voltage around 5 V.
Reliability of analog resistive switching memory for neuromorphic computing
Authors: Zhao Meiran , Gao Bin , Tang Jianshi , Qian He , Wu Huaqiang
Published: January 2020

As artificial intelligence calls for novel energy-efficient hardware, neuromorphic computing systems based on analog resistive switching memory (RSM) devices have drawn great attention recently. Different from the well-studied binary RSMs, the analog RSMs are featured by a continuous and controllable conductance-tuning ability and thus are capable of combining analog computing and data storage at the device level. Although significant research achievements on analog RSMs have been accomplished, there have been few works demonstrating large-scale neuromorphic systems. A major bottleneck lies in the reliability issues of the analog RSM, such as endurance and retention degradation and read/write noises and disturbances. Owing to the complexity of resistive switching mechanisms, studies on the origins of reliability degradation and the corresponding optimization methodology face many challenges. In this article, aiming on the high-performance neuromorphic computing applications, we provide a comprehensive review on the status of reliability studies of analog RSMs, the reliability requirements, and evaluation criteria and outlook for future reliability research directions in this field.
Coherence imaging spectroscopy at Wendelstein 7-X for impurity flow measurements
Authors: Perseo Valeria , Gradic Dorothea , König Ralf , Ford Oliver P. , Killer Carsten , Grulke Olaf , Ennis David A. ,   W7-X Team
Published: January 2020

In the last decade, Coherence Imaging Spectroscopy (CIS) has shown distinctive results in measuring ion flow velocities in the edge of magnetically confined plasma devices. Its 2D spatially resolved measurement capabilities and its high optical throughput are ideal for investigating the impurity behavior in the complex 3D magnetic island topology edge of Wendelstein 7-X (W7-X). However, a highly precise and stable calibration method is required for a reliable diagnostic operation. A new level of precision and stability has been achieved for the two CIS systems installed at W7-X with the use of a new calibration source, a continuous tunable laser commercially available only since 2015. A specific prototype model was successfully adapted to the challenging requirements of W7-X, granting high accuracy (±0.01 pm) and flexibility (spectral range: 450–650 nm) in the wavelength calibration required for measuring low-Z impurity ion flow velocities. These features opened up new investigation possibilities on temperature stability and wavelength response of the CIS components, allowing to fully characterize and validate the W7-X systems. The CIS diagnostic was operational throughout the last W7-X experimental campaign. Measured velocities on the order of ∼20–30 km/s were observed, corroborated by comparisons with measurements with Mach probes.
Time-resolved diffraction with an optimized short pulse laser plasma X-ray source
Authors: Afshari M. , Krumey P. , Menn D. , Nicoul M. , Brinks F. , Tarasevitch A. , Sokolowski-Tinten K.
Published: January 2020

We present a setup for time-resolved X-ray diffraction based on a short pulse, laser-driven plasma X-ray source. The employed modular design provides high flexibility to adapt the setup to the specific requirements (e.g., X-ray optics and sample environment) of particular applications. The configuration discussed here has been optimized toward high angular/momentum resolution and uses Kα-radiation (4.51 keV) from a Ti wire-target in combination with a toroidally bent crystal for collection, monochromatization, and focusing of the emitted radiation. 2×105 Ti-Kα1 photons per pulse with 10−4 relative bandwidth are delivered to the sample at a repetition rate of 10 Hz. This allows for the high dynamic range (104) measurements of transient changes in the rocking curves of materials as for example induced by laser-triggered strain waves.
High temperature (300 °C) ALD grown Al2O3 on hydrogen terminated diamond: Band offset and electrical properties of the MOSFETs
Authors: Ren Zeyang , Lv Dandan , Xu Jiamin , Zhang Jinfeng , Zhang Jincheng , Su Kai , Zhang Chunfu , Hao Yue
Published: January 2020

Hydrogen-terminated diamond (H-diamond) metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on a polycrystalline diamond substrate. The device has a gate length of 2 μm and uses Al2O3 grown by atomic layer deposition at 300 °C as a gate dielectric and passivation layer. The Al2O3/H-diamond interfacial band configuration was investigated by X-ray photoelectron spectroscopy, and a large valence band offset (3.28 eV) that is very suitable for p-channel H-diamond FETs was observed. Meanwhile, the measured O/Al ratio hints that there are Oi or VAl defects in the Al2O3 dielectric, which can work as an acceptorlike transfer doping material on a H-diamond surface. The device delivers the maximum saturation drain current of over 200 mA/mm, which is the highest for 2-μm H-diamond MOSFETs with the gate dielectric or passivation layer grown at 300 °C or higher temperature. The ultrahigh on/off ratio of 1010 and ultralow gate leakage current of below 10−12 A have been achieved. The high device performance is ascribed to the ultrahigh carrier density, good interface characteristics, and device processes. In addition, the transient drain current response of the device can follow the gate voltage switching on/off pulse at a frequency from 100 kHz to 1 MHz, which indicates the potential of the H-diamond FETs in power switch applications.
Orientation-selective elliptic optical vortex array
Authors: Wang Y. K. , Ma H. X. , Zhu L. H. , Tai Y. P. , Li X. Z.
Published: January 2020

We propose an orientation-selective elliptic optical vortex array (OS-EOVA). Using multicoordinate (namely, polar, Cartesian, and elliptic) transformations, three kinds of operations applied on optical vortex elements (including location, rotation, and stretching) were executed to obtain the desired orientation in the observed plane. Then, exploiting the reverse design technique, the above-mentioned operations were mapped onto the initial execution plane via Fourier transform. Based on this, 1D and 2D OS-EOVAs were generated experimentally and the existence of optical vortices was verified. Specific OS-EOVAs were designed, possessing antenna array orientation as well as radial and azimuthal orientation. Compared to existing OVAs, the OS-EOVA provides an additional modulated dimension, i.e., orientation. This technique will open up some potential applications, such as complex manipulation of multiparticle systems and fabrication of micromaterials with orientation.
Identification of trapping in a peristaltic flow: A new approach using dynamical system theory
Authors: Ehsan T. , Asghar S. , Anjum H. J.
Published: January 2020

In this paper, we propose a new approach for the identification of characteristic peristaltic flow features such as “bolus” and “trapping.” Using dynamical system analysis, we relate the occurrence of a bolus to the existence of a center (an elliptic equilibrium point). Trapping occurs when centers exist under the wave crests along with a pair of saddles (hyperbolic equilibrium points) lying on the central line. For an augmented flow, centers form under the wave crests, whereas saddles lie above (below) the central line. The proposed approach works much better than the presently adopted approach in two ways: (1) it does not require random testing and (2) it characterizes the qualitative flow behavior for the complete range of parameter values. The literature is somewhat inconsistent with regard to the terminologies used for describing characteristic flow behaviors. We have addressed this issue by explicitly defining quantities such as “bolus,” “backward flow,” “trapping,” and “augmented flow.”
Molecular dynamics calculation of thermal conductivity and shear viscosity in two-component fully ionized strongly coupled plasma
Authors: Bobrov A. A. , Bronin S. Y. , Klyarfeld A. B. , Zelener B. B. , Zelener B. V.
Published: January 2020

We present the results of calculations of thermal conductivity and shear-viscosity coefficients of ultracold single charged two-component classical Coulomb plasma by the method of molecular dynamics (MMD). The calculations are carried out in a wide range of Coulomb coupling parameters. The comparison with analytical expressions and calculations of MMD for the model of one-component plasma on a uniform background is presented for conditions where experimental measurements are lacking. The results obtained for our model can be used for any equilibrium or nonequilibrium strongly coupled plasmas, in which quantum effects are negligible.
Ion pair free energy surface as a probe of ionic liquid structure
Authors: Bernardino Kalil , Goloviznina Kateryna , Gomes Margarida Costa , Pádua Agílio A. H. , Ribeiro Mauro C. C.
Published: January 2020

Numerous combinations of cations and anions are possible for the production of ionic liquids with fine-tuned properties once the correlation with the molecular structure is known. In this sense, computer simulations are useful tools to explain and even predict the properties of ionic liquids. However, quantum mechanical methods are usually restricted to either small clusters or short time scales so that parameterized force fields are required to study the bulk liquids. In this work, a method is proposed to enable a comparison between the quantum mechanical system and both polarizable and nonpolarizable force fields by means of the calculation of free energy surfaces for the translational motion of the anion around the cation in gas phase. This method was tested for imidazolium-based cations with 3 different anions, [BF4]−, [N(CN)2]−, and [NTf2]−. Better agreement was found with the density functional theory calculations when polarizability is introduced in the force field. In addition, the ion pair free energy surfaces reproduced the main structural patterns observed in the first coordination shell in molecular dynamics simulations of the bulk liquid, proving to be useful probes for the liquid phase structure that can be computed with higher level methods and the comparison with forcefields can indicate further improvements in their parameterization.
The vibronic absorption spectra and exciton dynamics of plasmon-exciton hybrid systems in the regimes ranged from Fano antiresonance to Rabi-like splitting
Authors: Zhang Bin , Liang WanZhen
Published: January 2020

The complex interplay between molecules and plasmonic metal nanoparticles (MNPs) presents a set of particular characteristics in absorption/scattering spectra such as excitonic splitting, asymmetric line shapes, plasmon-induced absorption enhancement and transparencies, etc. Although the MNP-molecule systems have been intensively investigated experimentally and theoretically, the construction of a theoretical framework which can produce all the disparate experimental observations and account for the electron-phonon (e-p) coupling is still in progress. Here, we present a theoretical approach which can account for both the plasmon-exciton coupling and the e-p interaction and produce all the spectral line shapes ranging from Fano antiresonance to Rabi splitting by simply tuning the coupling strength or plasmon damping rate. Additionally, we demonstrate the evolution of vibronic spectra and exciton dynamics with the coupling strength, plasmon damping rate, and detuning energy. It is found that the vibronic structures appearing in Rabi-like spectra are worse resolved, wider, and more largely shifted than those appearing in the Fano regime, attributed to the more significant deformation of the molecular vibrational wavepacket in the Rabi-like regime than that in the Fano regime as the molecular e-p interaction increases. The positive/negative value of detuning energy can induce different degrees of the vibrational wavepacket deformation and subsequently a different effect on the spectra in different coupling regimes.
Dimension of reservoir computers
Authors: Carroll T. L.
Published: January 2020

A reservoir computer is a complex dynamical system, often created by coupling nonlinear nodes in a network. The nodes are all driven by a common driving signal. In this work, three dimension estimation methods, false nearest neighbor, covariance dimension, and Kaplan-Yorke dimension, are used to estimate the dimension of the reservoir dynamical system. It is shown that the signals in the reservoir system exist on a relatively low dimensional surface. Changing the spectral radius of the reservoir network can increase the fractal dimension of the reservoir signals, leading to an increase in a testing error.
Web buckle-mediated room-temperature ferromagnetism in strained MoS2 thin films
Authors: Ren Hongtao , Zhang Lei , Xiang Gang
Published: January 2020

Ferromagnetism of two-dimensional (2D) materials mediated by strain engineering has been extensively studied in theoretical calculations. However, due to the difficulty of introducing strain into 2D materials, experimental research has always been a challenge. We have fabricated MoS2 thin films using polymer assisted deposition and have observed strain-induced ferromagnetism in buckled MoS2 films. After buckling, the saturated magnetization (Ms) of buckled films at 300 K (0.486 emu·g−1) is enhanced 7.5 times compared to that of flat films (0.065 emu·g−1), while the linear temperature coefficient (χT) of buckled MoS2 films for E12g mode of Raman spectra is reduced to one third. Our results suggest that biaxial tensile strain plays a significant role in modulating magnetism, which may provide a feasible way for the fabrication and study of strain-related spintronic devices.
Hindered alignment in ultrashort, intense laser-induced fragmentation of O2
Authors: Sen Arnab , Sairam T. , Sahu S. R. , Bapat Bhas , Gopal R. , Sharma V.
Published: January 2020

Molecules ionized by intense (10–100 TW/cm2) and ultrashort (tens of femtoseconds) laser fields undergo rotation and alignment mediated through their polarizability. The expected alignment is indeed observed in the case of O2 molecules ionized by intense laser pulses of 800 nm wavelength and 25 fs duration, as observed through velocity imaging of the fragments. Strikingly, when 35 fs pulses of 400 nm wavelength of comparable intensity are employed, an anomalous hindering of this alignment is observed. In both cases, we propose dissociation pathways for the energetic ions consistent with the recorded kinetic energy distributions. Using a semiclassical model of induced rotation of the molecular ion that involves polarizabilities of the participating excited states, both behaviors are reproduced. The model suggests that the difference in the observations can be attributed to a transient negative polarizability in an intermediate state of the proposed pathway.
Crystal structures and rotational dynamics of a two-dimensional metal halide perovskite (OA)2PbI4
Authors: Hu Xiao , Zhang Depei , Chen Tianran , Chen Alexander Z. , Holmgren Eric N. , Zhang Qiang , Pajerowski Daniel M. , Yoon Mina , Xu Guangyong , Choi Joshua J. , Lee Seung-Hun
Published: January 2020

The extended charge carrier lifetime in metal halide perovskites is responsible for their excellent optoelectronic properties. Recent studies indicate that the superb device performance in these materials is intimately related to the organic cation dynamics. Here, we focus on the investigation of the two-dimensional hybrid perovskite, (C8H17NH3)2PbI4 (henceforth, OA+ = C8H17NH3+). Using elastic and quasielastic neutron scattering techniques and group theoretical analysis, we studied the structural phase transitions and rotational modes of the C8H17NH3+ cation in (OA)2PbI4. Our results show that, in the high-temperature orthorhombic (T > 310 K) phase, the OA+ cation exhibits a combination of a twofold rotation of the NH3–CH2 head group about the crystal c-axis with a characteristic relaxation time of ∼6.2 ps, threefold rotations (C3) of NH3 and CH3 terminal groups, and slow librations of the other atoms. Contrastingly, only the C3 rotation is present in the intermediate-temperature orthorhombic (238 K < T < 310 K) and low-temperature monoclinic (T < 238 K) phases.
Drag reduction by linear flexible polymers and its degradation in turbulent flow: A phenomenological explanation from chemical thermodynamics and kinetics
Authors: Zhang Xin , Duan Xili , Muzychka Yuri
Published: January 2020

Based on chemical thermodynamics and kinetics analysis, this work provides a phenomenological explanation of drag reduction and its degradation by linear flexible polymers. We propose that drag reduction happens due to the unstable thermodynamic environment created by the elongation of free polymers and aggregates, and degradation of drag reduction happens due to the unstable kinetic environment with the chain scission of the free polymer and aggregate. Experimental results from microscopic and macroscopic scales further validate the proposed theory. Fourier series is employed to explain the molecular weight distribution that happens in the drag reduction.
Low-barrier Mott diodes with near-surface polarization-induced
δ
-doping
Authors: Vostokov N. V. , Drozdov M. N. , Khrykin O. I. , Yunin P. A. , Shashkin V. I.
Published: January 2020

The possibility of a controlled decrease in the effective height of the Schottky (Mott) barrier to the AlGaN/GaN (Ga-face polarity) heterostructure due to the modification of the shape of the barrier by the electric field of the polarization charge arising in the plane of the heterojunction because of the jump in electric polarization is experimentally shown. A decrease in the effective barrier height is related to an increase in the role of electron tunneling through the barrier. The effective barrier height can be controlled by varying the thickness and chemical composition of the AlGaN layer and choosing the metal of the barrier contact. Test low-barrier Mott Ti/AlGaN/GaN diodes demonstrating high values of the ampere-watt sensitivity (9 A/W) for a low specific differential resistance (4 × 10–4 Ω⋅cm2) at zero bias have been manufactured.
Hydrogen behavior under X-ray irradiation for a-IGZO thin film transistors
Authors: Kim Dong-Gyu , Lee Tae-Kwon , Park Kwon-Shik , Chang Youn-Gyoung , Han Kyong-Joo , Choi Duck-Kyun
Published: January 2020

We studied hydrogen (H) behavior in amorphous In-Ga-Zn-O (a-IGZO) films under X-ray irradiation by evaluating the threshold voltage (VTH) shift in a-IGZO thin film transistors (TFTs) with different H concentrations in the active layers. We fabricated three types of a-IGZO TFTs: (i) one without a buffer layer and postannealed in N2, (ii) one with a H-resolved buffer layer and postannealed in N2, and (iii) one with a H-resolved buffer layer and postannealed in a mixture of N2 and H2. All three TFTs showed a negative VTH shift after 100 Gy of X-ray exposure. The degree of VTH shift correlated with an increase in conductivity, which, in turn, corresponds to the H concentration in the active layer of the as-fabricated TFTs. Based on spectroscopic ellipsometry analysis, we confirmed a large increase in the donorlike H related D1 state after X-ray irradiation in high-H concentration a-IGZO films. In addition, an increase in the number of H2 molecules in a-IGZO films after X-ray irradiation was observed via thermal desorption spectroscopy analysis. Therefore, we conclude that the increase in conductivity and/or the resulting negative VTH shift in a-IGZO TFTs during X-ray irradiation can be attributed not only to the state transition from acceptorlike to donorlike H in the as-prepared a-IGZO but also to the incorporation of additional H radicals generated by X-ray irradiation.
Brownian-particle motion used to characterize mechanical properties of lipid vesicles
Authors: Sandoval-Jiménez Idalia M. , Jacinto-Méndez Damián , Toscano-Flores Liliana G. , Carbajal-Tinoco Mauricio D.
Published: January 2020

We present a method that takes advantage of the Brownian motion of a colloidal particle to experimentally determine the area stretch modulus of giant liposomes in solution, in regard to the continuum mechanics theory of elasticity. The characteristic parameters of the corresponding model are measured by using the three-dimensional version of digital video microscopy. Such an approach makes use of the diffraction pattern generated by fluorescent spheres found below the focal plane of the microscope objective, allowing the spatial location of the sphere and, thus, the reconstruction of its trajectory. When this particle probe is localized in the neighborhood of a bilayer membrane, its motion causes an elastic distortion of the membrane that is quantifiable. More importantly, such deformation is related to the mentioned modulus, whose measured values are consistent with experimental data obtained through well-known techniques.
Broadband modulation of subwavelength topological interface states in a one-dimensional acoustic system
Authors: Wang Zhenyu , Zhao Degang , Luo Jinlong , Wang Rongli , Yang Hai
Published: January 2020

The acoustic analogy of topological insulators is a hot field of materials research. On one-dimensional acoustic systems, many researchers have lately paid their attention to the applications of the Su-Schrieffer-Heeger (SSH) model, which can support topologically nontrivial phases. In this paper, we design a supercell composed of two identical hollow cylinders with a side split immersed in the air background. The supercell is arranged in a line to form a SSH model, which has three bandgaps including two zone-folding-induced gaps and a local resonant gap in the subwavelength region. By analyzing the eigenstates and calculating the Zak phases, we find that a topological phase transition takes place only in the zone-folding-induced gaps when we rotate the split-cylinders. Thus, a finite-size array, made of two sublattices with distinct topological properties, inevitably produces topological interface states on their interface. In addition, we demonstrate that the topological interface states can be adjusted in a wide frequency range by rotating the cylinders that control the coupling strength between two split-cylinders in one supercell. These tunable topological interface states may have potential application prospects in wave filtering, wave detecting, and so on.
Schwinger-Dyson equations for composite electrolytes governed by mixed electrostatic couplings strengths
Authors: Buyukdagli Sahin
Published: January 2020

The electrostatic Schwinger-Dyson equations are derived and solved for an electrolyte mixture composed of monovalent and multivalent ions confined to a negatively charged nanoslit. The closure of these equations is based on an asymmetric treatment of the ionic species with respect to their electrostatic coupling strength: the weakly coupled monovalent ions are treated within a gaussian approximation, while the multivalent counterions of high coupling strength are incorporated with a strong-coupling approach. The resulting self-consistent formalism includes explicitly the interactions of the multivalent counterions with the monovalent salt. In highly charged membranes characterized by a pronounced multivalent counterion adsorption, these interactions take over the salt-membrane charge coupling. As a result, the increment of the negative membrane charge brings further salt anions into the slit pore and excludes salt cations from the pore into the reservoir. The corresponding like-charge attraction and opposite-charge repulsion effect is amplified by the pore confinement but suppressed by salt addition into the reservoir. The effect is particularly pronounced in high dielectric membranes where the attractive polarization forces lead to a dense multivalent cation layer at the membrane walls. These cation layers act as an effective positive surface charge, resulting in a total monovalent cation exclusion and a strong anion excess even in the case of neutral membrane walls.
Capturing static and dynamic correlation with ΔNO-MP2 and ΔNO-CCSD
Authors: Hollett Joshua W. , Loos Pierre-François
Published: January 2020

The ΔNO method for static correlation is combined with second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster singles and doubles (CCSD) to account for dynamic correlation. The MP2 and CCSD expressions are adapted from finite-temperature CCSD, which includes orbital occupancies and vacancies, and expanded orbital summations. Correlation is partitioned with the aid of damping factors incorporated into the MP2 and CCSD residual equations. Potential energy curves for a selection of diatomics are in good agreement with extrapolated full configuration interaction results and on par with conventional multireference approaches.
Analysis of a 6-DOF parallel robot motion simulation
Authors: Miclosina C O , Cojocaru V , Korka Z I
Published: January 2020

The paper presents the geometrical model of a parallel topology robot of MSSM type, operated as a flight simulator. Certain strokes of the driving kinematical joints lead to the simulation of real limit situations, which are dangerous for the human operator, such as a sudden pitch movement. The variations of different motion parameters are analyzed. SolidWorks software was used in the modeling and simulation processes.
PLC programming to optimize water flow in secondary cooling zone
Authors: Tirian G O , Chioncel C P , Holubeck R , Cinkar K
Published: January 2020

In the paper was made PLC programming, with which an adaptive system was implemented, was used the Simatic Manager Step 7 software, which is specific to the chosen PLC Simatic S7-300. Input data, computation relationships and correlations between the different sizes were retrieved and processed from the database of the two human operators, commanding the opening of the valve automatically. With this software, it was possible to eliminate the human factor in controlling parameters specific to the continuous casting secondary cooling zone.
The kinematic and kinetostatic study of the shaker mechanism with SolidWorks Motion
Authors: Nedelcu D , Gillich G R , Bloju A , Padurean I
Published: January 2020

The objective of the paper is to calculate the kinematic and dynamic behaviour of the shaker mechanism and compare the theoretical with the following SolidWorks Motion results: the positional analysis, kinematic analysis of velocities, kinematic analysis of accelerations and kinetostatic analysis.
Principles of development of product lifecycle management system for threaded connections based on the Python programming language
Authors: Kopei V B , Onysko O R , Panchuk V G
Published: January 2020

The principles of the development of PLM-system for threaded connections of oil and gas equipment are described. In order to ensure efficiency, the PLM-system must be isomorphic to other complex systems and have their laws, in particular, the emergence and “requisite variety”. The proposed system belongs to the class of hybrid multi-agent intelligent systems that combine various methods of knowledge representation and decision making. The system contains a knowledge base with inference rules, an inference engine, a code editor, simulation models of threaded connections, the results of their simulations, and other components. The knowledge base contains facts, in which the factors that affect the reliability and durability of threaded connections, are connected by cause-effect relations “is the cause” and “is the effect”. Facts can have such properties as an information source, dependence of quantities, a simulation model, etc. The rules of inference allow you to get new facts from the knowledge base and simulation models. All system components or their software interfaces are developed in a high-level general-purpose programming language Python, which simplifies the implementation of the system and the integration of components with different types. In particular, any Python package can be easily connected to the system. Classes and individuals of ontology are declaratively described by Python classes and objects, attributes and relationships are Python-attributes. For easy editing, the system code is divided into parts, which are combined before execution.
Investigation of the technological damageability of castings at the stage of design and technological preparation of the machine Life Cycle
Authors: Kusyi Y M , Kuk A M
Published: January 2020

Solution of the problem of machines reliability requires new approaches which at the present stage of machine-building industry development is realized by implementing PLM - conceps (Product Lifecycle Management). The PLM - concepts are the system of management of the machine parts life with design of the functionally-oriented technologies of production by means of parallel engineering.

Complex conditions of the products exploitation and complex technological processes of treatment require their profound theoretical and experimental investigation. An important task in the mechanical treatment and operation of products from the standpoint of their reliability is to predict their behavior at a certain point of time.

The LM-hardness method developed under the guidance of academician A.A. Lebedev to control the samples structure quality and materials damageability in the investigated part of the samples is proposed. According to the LM-hardness method derivatives of the physical parameters absolute values, for example, dissipation of the obtained control results carried out by the same devices in identical conditions serve as the evaluation criterion.

Homogeneity is a parameter that integrally describes the material state when processing the results of hardness control. The homogeneity is described by the Weibull coefficient m and the known Gumbel formula.

In our researches we propose to evaluate the analysis of the material structure state both by means of the Weibull coefficient m, and its technological damageability W, which is inversely proportional to the Weibull coefficient.

The experimental researches were carried out on aluminium alloy castings in sand moulds.Distribution of the technological damages W by the height of castings is established on the basis of performed researches at the stage of process engineering. The influence of the parameters of the “Sandvik” company tool design in treatment, using the “HAAS” treatment equipment on the change of the Weibull coefficient m is analyzed.
Research of probability characteristics of current and voltage unbalance based on using graphs of load for the duration at the substation
Authors: Miroshnyk O , Kovalyshyn S , Tomporowski A , Kruszelnicka W , Bałdowska-Witos P
Published: January 2020

The theoretical study and recommendations on the practical application of methods for calculating the probability of asymmetry in the four-wire networks of 0.38/0.22 kV were carried out through using the load curves in the duration at the substation. We cited a group of curves, which show the variation of coefficient of filling the graphs from the share of power consumers in the total load for the consumer substations with different installed capacity.
The research of the spectral characteristics of the voltage inverter exciter bandwidth
Authors: Miroshnyk O , Lysychenko R , Kovalyshyn S , Kruszelnicka W , Bałdowska-Witos P , Tomporowski A
Published: January 2020

The analysis of the structural scheme of the reflectometric system exciter was carried out. We show that the basic block diagram for the construction of range of the inverter is a single ring exciter digital frequency synthesizer. The mathematical model of range of the inverter exciter provides an analysis of the structural schemes of inverter with pathogen spectral methods. These expressions of the spectral power density of the phase fluctuations allowed to take into account the effect of the circuit elements of the inverter of the pathogen on its spectral characteristics and calculate the dispersion, the average deviation of the phase in the frequency band and the mean square raid exciter output signal phase.
Life cycle assessment of beverage bottles
Authors: Bałdowska-Witos P , Kruszelnicka W , Tomporowski A
Published: January 2020

Poland ranks sixth in Europe (behind Germany, Italy, France, Spain and England) in terms of demand for plastics, and the Polish plastics processing industry used in 2017 to produce about 3.5 million tons of polymer materials, in view of total demand in Europe estimated at approx. 51.5 million tons. It is assumed that Polish industry uses about 7% of total demand in Europe. In Poland, about 33% of the domestic demand for plastics is directed to the packaging industry. Along with the growing demand for plastics, packaging production and social consumption are increasing. The article presents the sources of greenhouse gas emissions from the food industry. An LCA (Life Cycle Assessment) analysis was carried out that identifies potential environmental burdens for the bottle forming process. The scope of work included selected stages of shaping bottles made of two types of PET and PLA polymer materials. The aim of the work was to demonstrate the impact of bottle production on the condition of the natural environment and to indicate the factors determining these influences.
Aspects of using a numerical simulator for a robot position-orientation matrix determination
Authors: Miclosina C O , Halalae I
Published: January 2020

The paper presents the mathematical model of a parallel topology robot of FP3+3·RRS+MP3 type, used in order to determine the position-orientation matrix of the robot’s mobile reference system. By using a numerical simulator, positions of the characteristic point are plotted in the 3D space.
Antioxidant activity of environmentally - friendly noble metallic nanoparticles
Authors: Sorescu A A , Nuta A , Grigore M , Andrei E R , Radu G I , Iancu L
Published: January 2020

This research paper presents the environmentally - friendly synthesis of two noble metallic nanoparticles, namely silver (AgNPs) and gold (AuNPs), from ten different plants with proven pharmaceutical benefits, e.g.: Sea buckthorn, Elderflower, Lungwort, Acacia, Cornflower, Ramson, etc. Both AgNPs and AuNPs are prepared via two routes: at room temperature, in the dark, for 24 hours and at 50°C under a constant stirring of 600 rpm for 30 minutes. UV - Vis spectroscopy was used to investigate the formation of both AgNPs and AuNPs and compared to the UV – Vis spectra of the plain aqueous extracts prepared at 4°C. The main purpose of our research was to investigate the antioxidant activity of the aqueous extracts and noble metallic nanoparticles obtained thereof and to determine whether the temperature-conducted environmentally - friendly synthesis of AgNPs and AuNPs influences the antioxidant activity in any way.
Research regarding the hardness of cast iron
Authors: Bucur F , Socalici A , Josan A , Putan V
Published: January 2020

Brake blocks for rolling stock are made of phosphorous cast irons or composite materials. In cast iron brake blocks, their structure and mechanical characteristics are influenced by their chemical composition. Through the research and experiments done, there have been established correlations between chemical composition and hardness. The correlations are presented both in analytical and graphical form, as well as their analysis from a mathematical and technological point of view. The regression areas allow the identification of the optimal areas of variation of the analyzed parameters.
Influence of steel vacuuming on the reduction of hydrogen content
Authors: Radu M , Serban S , Popa E , Heput T
Published: January 2020

Under the current technological development, steel consumers are increasingly demanding high quality steels, one of the conditions imposed is the content of gases (hydrogen and nitrogen). At the world level in the technological process of steel production, there are provided facilities for the processing of liquid steel in ladle, at least of type LF-ladle furnace and VD- vacuum degassing. In the researches and experiments carried out the possibilities of the advanced reduction of the hydrogen content, respectively the increase of the elimination level, were considered. As a factor of influence on the aforementioned parameters were chosen: the total duration of the vacuum, the duration of deep vacuum, the vacuum pressure, the inlet-outlet temperatures in the vacuum degassing installation and the distributor. The data obtained were processed in the EXCEL and MATLAB, and on the basis of the technological analysis of the obtained results the optimal limits of variation of the technological parameters were set in order to achieve the aim pursued.
Researches regarding increase of impact resistance for welded structures by weld micro-alloying
Authors: Zgripcea L , Heput T , Putan V , Ardelean M
Published: January 2020

In industrial fabrication, structural steel is the most used grade used in structures and automotive. For these grades, in the last decade automation and standardization leaded to increase of mechanical properties and reduction of fabrication cost. In parallel, control of alloying elements and impurities realized especially in vacuum treatment stations ensured higher mechanical properties in a larger temperature domain. The research scope is to increase of mechanical properties for weld line and obtain higher properties than the base metal. Final goal is to obtain steel structures assembled by welding safer in exploitation. Key point of the research is to increase the impact resistance for weld line by micro alloying and determine the optimum percentage for nickel element inside weld metal.
Analysis of wastewater sludge drying process in vacuum filters
Authors: Flori M , Vîlceanu L
Published: January 2020

The paper presents a case study on wastewater sludge drying in a vacuum filter. Using finite element analysis it is estimated the variation with cake height, along its centerline, of temperature, liquid and gaseous phase ratios. Numerical results are estimated after 30 hours of drying at different temperatures (60°C, 80°C and 100°C), considering a sludge initial moisture content of 20%.
An exploratory analysis on challenges prevailing in small and medium IT firms
Authors: Soman Sandhya , Pareek Piyush Kumar
Published: January 2020

There is lot of challenges being faced by IT Firms. Be it the pressure on companies to deliver reliable software’s with lesser lead times, pressure to perform at par with market competitors, constant push to deliver quality software; there are several such challenges being faced by these firms. In this research paper, we want to focus our attention to small IT Firms and to understand their challenges by conducting a survey with the help of a structured questionnaire. The questionnaire is designed through the past problems highlighted in literature and a validated through responses from industry practitioners. The opinions are recorded and the relationship between the variables are analysed to give a better understanding of the present challenges in small IT Firms. The work presented in this paper is the first phase towards the development of a framework targeted towards SME IT firms for whom increased lead time is a primary bottleneck. In order to solve a problem, it is essential to understand it in depth and to analyse if there is any gap between the perceived bottles presented in the literature, and the actual problems faced in the industry. Hence, in order to bridge that gap, we have made an effort to structure out the questionnaire based on our findings and have tried to determine if the same can be validated through the responses acquired from the industry in practice.
Implementation of Fuzzy Logic in Estimating Yield of a Vegetable Crop
Authors: Upadhya S Mamatha , Mathew Soya
Published: January 2020

Predicting the influence of climate variations on crop yield demands an appropriate model. In this study, Fuzzy logic based crop yield estimation is undertaken considering temperature, humidity and moisture of soil as input parameters. By subjecting these parameters to fuzzy arithmetic, crisp value of yield is obtained. Trapezoidal membership function is considered in the fuzzy modeling. The results are validated using available open source literature. It has been verified theoretically that air humidity 65%-75%, air temperature 18-290 C and soil moisture 60-80% would give high yield.
Design and Enactment of Heart Attack deduction using IoT Measuring Device
Authors: Margaret Mary T , Ramanathan G , Sangamithra A , Soumya K
Published: January 2020

These days we’ve an enhanced range of heart diseases together with enhanced risk of heart attacks. We all heard and observed that heart attack can kill your life in 3 attempts but now days because of heavy stress it could be in first attempt also. If conscious about our health regularly on regular basis then we can detect so many different diseases by detecting them previously, and Co2 would be also varies in the heart attack situation, so in this paper carbon dioxide analyses and identified the intense of CO2 in different level of activities. Life is precious. In this era many people lose their life to coronary failure. Heart attack detection is not easy task. In today’s world heart attack is more common, In order to overcome the situation and to reduce the death rate due to heart attack, this system is used and mainly it will useful for the society In this system we have a tendency to area unit implementing a heartbeat observance and coronary failure detection system exploitation the Internet of Things. In this sensor the operator can fix the low as well as higher level heart beat, where the system monitor the beat and send those data to the internet, in case if the heart beat level go beyond the; low rate which is set by the user, the alert will be given so that immediate action can be taken. One is that the transmittal circuit that is with patient and therefore the different is that the receiver circuits that is being supervised by the doctor or nurse. The main motive of the system which will take the heart beat rate and those data will be get displayed on the digitalized Monitoring screen.
Rethinking Urban Public Space: Physical and Functional Analysis through Visual Surveys
Authors: Abdul Rahman N , Ghani I , Teh M Z , Ibrahim K A
Published: January 2020

Pedestrian-friendly, liveable, sociable human scale and fun urban environment are the qualities for good cities. Human activities will happen in urban public places if cities can offer choices for people. Increasing the use of the spaces in an urban environment through human activities can turn urban spaces into becoming “places” that is crucial to create good cities. Urban spaces should cater the functional, social, and leisure needs of people. It has positively related to a sense of community that contributes to the identity and image of the city. Therefore, urban street planning and design need to emphasis more on crucial aspects such as the physical, social, cultural, economics and pedestrians to create an urban street environment that is attractive as a destination for economic and social activities. This paper aims to propose and discuss optimal design solutions for a better urban street environment in Ipoh old town, Perak. The objectives are 1) to identify nodes and linkages, qualities of place and fabrics of the spaces and; 2) to determine relationships between the quality of the physical environment of the street and social activities that contribute to the use of the spaces. The study adopted a qualitative methodological strategy. Visual surveys were used to observe the relationship between the physical urban environment and the users’ activities in Ipoh old Town, Perak. Field observation was conducted to gather evidence focusing on the functional aspects of the actual scenes of the place through physical and activity mapping. This study has found that the relationship between the physical environment and the users’ activities significantly influenced the quality of place and fabric of the Ipoh town and in turn, contribute towards reimagining identity of Ipoh as a prominent heritage town.