bluuebunny/crossref_metadata_2025 huggingface dataset:
Model Predictive Control for rotary inverted pendulum using LabVIEW
Authors: Deepak K N , Rahul Sharma K , Ananthan T
Published: December 2019

Inverted pendulum is a popular nonlinear system, extensively used in the study and analysis of various control techniques. Inverted pendulum has got variety of applications in robotics, aerospace, Segway etc. The paper deals with mathematical modelling, parameter estimation, disturbance rejection and tracking control of QNET 2.0 Rotary Inverted Pendulum Board for NI ELVIS in LabVIEW platform. A Model Predictive Controller is designed to maintain the pendulum in upright position and to handle disturbances. The tracking control problem for arm angle is also considered. A comparison between the disturbance rejections using MPC with standard LQR is carried out. Finally experimental results are described and compared based on the two control techniques designed for the stabilization of rotary inverted pendulum.
Vibration Based Fault Monitoring of a Compressor using Tree-based Algorithms
Authors: Prashanth Kotha , Elangovan M
Published: December 2019

Reciprocating air compressors are used as a part of manufacturing and engineering industries to offer pressurized air, which is utilized for different productive purposes. Compressors are trusted upon to be prepared and readily available as and when required and any interim stoppage or interruption will affect the manufacturing processes that are dependent on compressed air. From the reports of any maintenance engineer, one can find that in a reciprocating air compressor, components like bearings, valve blade, V-belt and piston rings add to a more noteworthy level of failure. Researchers do make attempts to find a suitable device that is profoundly welcome by the industry, for diagnosis of the fault that recommends a remedial action. Towards this direction, a study was attempted and vibration signals were collected from an experimental setup under supervised learning technique. Statistical features of the same were extracted for various combinations of fault conditions and analyzed using different tree-based algorithms with an intention to find the best one that will classify the fault with more accuracy and with the least computational time.
Multi-Criteria Engine Selection for Unique Purpose using AHP
Authors: Naveen Kumar V , Pranav Raja R S , Sanjeevi K S , Anbuudayasankar S P , Srihari S
Published: December 2019

In this automotive world the selection of a vehicle based on engine plays a major role, in which all the parameters of the engine need to be considered. The engine selection for three purposes has been considered in this paper. Most influencing 10 parameters of each purpose have been shortlisted with the help of experts in the respective field. Then the parameters are ranked with the help of Analytical Hierarchy Process (AHP). It helps to prioritise the parameters while selecting an engine for specific purpose. In AHP the relative matrix is formed by using pairwise comparison with the help of experts then the relative matrix is squared and eigen vector is found. The eigen vector is used to rank the parameters and is reported as per the priority for the respective purpose. The method proposed in this paper can be used as a decision-making tool while selecting an engine for a specific purpose.
Study on wear behaviour of Al7075 metal matrix composite with reinforced Gr and Nano TiO2 particles by Taguchi method
Authors: Danappa G T , Swamy R P
Published: December 2019

The hybrid metal matrix composite coating has found wide spread applications in the field of aerospace and automobile industries. In the present work the Al7075 is used as the major material and Gr micro particles along with nano TiO2 particles are reinforced in the composite material. The influence of wear parameters on the wear rate is calculated by Taguchi L9 array. Normal load, speed and distance are considered as the three parameters in the three levels. Further work is concentrated on the influence of percentage of nano particles in the composite and wear rate and hardness are evaluated. The results reveals that an increase in the wear resistance.
Ag-Cd-B-P ternary alloy with efficient electrocatalytic activity towards hydrogen evolution reaction (HER)
Authors: De S , Karfa P , Majhi K C , Madhuri R
Published: December 2019

Recently, a stable and effective Pt-free electrocatalyst is hugely required for hydrogen generation through water splitting. In this article, we present an easy synthesis of very small particle sized electrocatalysts Ag-Cd-B-P and Cd-Ag-B-P with good catalytic activity and stability for electrochemical hydrogen evolution reaction in acidic medium. Ag-Cd-B-P catalyst exihibits better performance than Cd-Ag-B-P with lower onset potential of - 0.25 V, higher electrochemical surface area of 0.50 cm2, excellent current density of 1.18 A/cm2 at – 1.29 V, low tafel slop of 118 mV/dec and small overpotential of 50 mV to achieve 10 mA/cm2 current density. The reported Ag-Cd-B-P electrocatalyst shows good storage stability of 2 months in normal condition with only ∼2 % change in onset potential and current density.
Impact of tungsten on the surface of aluminium-silicon alloy on microstructure, hardness and wear rate using GTA
Authors: Saravanan R , Nair Sandeep , Krishnakumar M
Published: December 2019

A study was carried out to determine the effect of tungsten addition on hardness, microstructure and wear behaviour of surface modified as-cast Al - Si alloy. The heat source utilized for modifying the surface of the substrate was Gas Tungsten Arc. Tungsten were deposited on the Al - Si alloy substrate using poly vinyl alcohol as binder and the SMP were performed. By using Lyzer Instruments optical microscope and HITACHI SU6600 FE-SEM microstructural analysis was carried out. The hardness and wear rate of the modified layer were calculated by using a micro-hardness tester and a pin-on-disc wear tester machine. The presence of elemental composition in the modified layer was determined by using Energy Dispersive Atomic X-ray Spectroscopy and its confirmation through XRD analysis. It was inferred from this study that a fine grain microstructure was observed in the modified layer. The hardness and wear resistance was found to increase as a result of W addition and also due to the formation of dispersion strengthening mechanism. The coefficient of friction was found to be independent of the hardness.
Tribo-Mechanical Behaviour of Al-Cu-Si castings
Authors: Naveen E , Ilangovan S
Published: December 2019

Al-Cu-Si alloy of 1.5% copper and 0.5% silicon was sand casted into ingot rods with Nitrogen degassing. The sand casted rods were homogenized at different temperatures for a time of 10 hours. The homogenized and as cast rods were then tested for mechanical and tribological properties by taking samples from different regions surface, middle and inner regions respectively. The Microhardness, microstructure, Ultimate tensile strength(UTS), elongation in percentage (%), rate of wear and specific wear rate were determined and investigated. The results show improved mechanical and tribological properties of homogenized compared to as cast. The hardness and tensile strength values showed similar pattern of decrease from outer to middle to inner regions whereas elongation in percentage showed the opposite. The greater hardness and tensile strength at the outer surface can be attributed to the faster solidification (or higher cooling rate at the surface) compared to the slower cooling rate at inner region of ingot. Microstructure examination also revealed finer grains at inner The Adhesive wear properties were determined using Pin on Disc wear tester as per ASTME standards of dry sliding friction condition. The results showed adhesive dry Adhesive wear is carried out by Pin-on-Disc wear tester. Wear rate of the alloy rises with applied load conducted at different speeds. The specific wear rate and the friction coefficient vary with load. The diffusion of disc material into the specimen material which changes the alloy composition. It was observed through energy dispersive X-ray spectroscopy (EDX) analysis. The worn-out surfaces were studied by using SEM analysis.
Design, manufacturing and testing of re-configurable crawling modular robot inspired from origami
Authors: Satyanarayana Pillai S , Sreedharan Pramod
Published: December 2019

This paper proposes a new type of origami inspired modular crawling robot that can be used for search and exploration purposes. Origami is an art of paper folding where a 2D sheet of material is folded into a 3D robotic structure. The origami inspired design introduces a low cost manufacturing technique and hence reducing the overall cost of the robot. This robot also has characteristics of modular robots. These robots can be connected, disconnected and re-connected to obtain different configurations. The prototype of the robot is manufactured and two types of crawling locomotion are implemented. Various test cases were created and tested under laboratory conditions. The robot was also tested to validate the characteristics of origami robots, modular robots and crawling locomotion is also implemented in unstructured environment. The first section in your paper
Erosion behaviour of graphitic carbon nitride (g-C3N4) reinforced epoxy composites
Authors: Pratap Naidu P , Raghavendra Gujjala
Published: December 2019

This paper deals with the manufacture and examination of tribological properties of epoxy composites reinforced with graphitic carbon nitride (g-C3N4) nanopowder. The composites had prepared with five different proportions of g-C3N4 nanopowder using a hand layup process. Comparison of tribological properties has made between the composites laid at different percentages of g-C3N4 in epoxy. The results showed the maximum erosion resistance of g-C3N4 particulate polymer matrix for 3% filler content. Also, by Scanning Electron Microscope (SEM), the erosion morphology analysis is done on the internal structures of the specimen.
Influence of Extending the Height on the Vortex Structures Generated Inside A Lid Driven Cavity
Authors: Kumar Sourav N , Akhilesh Vishnu H , Ajith Kumar S
Published: December 2019

A numerical study is conducted to study the effect of aspect ratio (extending the height) on the natural convection flow inside a square cavity. 2D incompressible equations are solved using the open CFD package OpenFOAM. A domain and grid independence study is conducted for getting the optimum dimensions and the grid size used in the problem. The validation is done for benchmark problems before applying on to the problem. The vortices formed inside the enclosure is identified by the help of streamlines. This paper clearly discusses the different regimes formed by changing the aspect ratio.
Regenerative chatter control in turning process using constrained viscoelastic vibration absorber
Authors: Ganapathy Ram H V , Saravanamurugan S
Published: December 2019

This paper focuses on utilization of viscoelastic material to control regenerative chatter in turning process. Self-induced vibrations can lead to the condition called regenerative chatter which produces violent relative vibrations between cutting tool and workpiece and reduces tool life and productivity. The regenerative chatter in turning processes can be controlled by maximizing negative real part of the frequency response function of cutting tool structure. In order to achieve this, a constrained viscoelastic vibration absorber (CVVA) is used. A CVVA consists of a viscoelastic material, such as natural rubber, which is sandwiched between two similar or dissimilar metallic layers. The CVVA is used as a cantilever beam whose fundamental natural frequency is tuned to the natural frequency of the dominant mode of cutting tool/tool holder. The optimum stiffness and damping coefficient of the CVVA are found using a numerical optimization technique and these optimal values are used to find the dimensions of CVVA. The resulting natural frequency of CVVA is verified using finite element simulation software ANSYS. The effectiveness of CVVA in controlling regenerative chatter in a compact CNC lathe is also analysed by constructing stability lobes which are plots of depth of cut vs spindle speed.
Synthesis of poly (ethylene glycol) (PEG)-capped Fe3O4 nanoclusters by hydrothermal method.
Authors: Anil Abhiram C , Govindan Kadarkarai , Rangarajan Murali
Published: December 2019

In the present work, we report the synthesis of poly (ethylene glycol)-capped iron oxide nanoclusters of spherical morphology by hydrothermal method. The synthesized particles were characterized by X-ray powder diffraction (XRD), Dynamic Light Scattering (DLS), Field Emission Scanning Electron Microscope (FESEM)/Energy dispersive spectroscopy (EDS) and Fourier Transform Infrared Spectroscopy (FT-IR). The effects of reaction parameters such as reaction temperature, time and hydrolysis ratio on the properties of PEG capped Fe3O4 have been studied. XRD confirms the presence of cubic spinel structure of Fe3O4 phase. FESEM images show spherical morphology of particles and particle sizes are ∼ 100 to 200 nm. DLS analysis shows the hydrodynamic size to be ∼ 151 to 512 nm for PEG capped Fe3O4nanoclusters dispersed in water. FT-IR confirms coating of PEG on Fe3O4 surface.
Hydrodynamic Characterization and Performance Evaluation of Polypyrrole Actuator Propulsor
Authors: Panda S K , Bandopadhya D
Published: December 2019

Polypyrrole, a special class of smart material has gained attention as artificial muscle actuator propulsor due to its promising properties like light weight, flexibility, large dimensional changes with low operating voltage and natural muscle like working and performances. In this paper, a Polypyrrole actuator is fabricated and studied its behaviour and performances in underwater environment experimentally. The actuator is synthesized by electrochemical polymerization and fabricated as a trilayer strip actuator by using layer by layer deposition technique. Following the fabrication, the hydrodynamic bending performances like tip displacement, force and frequency and propulsion characteristics like thrust, power and efficiency are estimated by carried out the bending experiment in a water tank with zero flow velocity. Here the stiffness of the actuator also estimated from dynamic mechanical analysis as it is one of the key parameter which affects the thrust generation. The operation life of the actuator is estimated for underwater operation and analyzes the various parameters and their relation with PPy actuator performances to find the primary controlling parameters. Finally, the present actuator is compared with existing smart material based underwater actuator to study the feasibility of the actuator. From the present study, it can be believe that the proposed PPy actuator propulsor is suitable for underwater bio-inspired robotics motion and may use for various applications like scanning, surveillance and exploration.
Friction and sliding wear studies on functionally graded Al LM25/WC composite
Authors: Jojith R , Radhika N
Published: December 2019

Functionally graded LM25/15 wt.% Tungsten carbide composite of dimension Øout 150 mm x Øin 110 mm x 100 mm and thickness 20 mm was studied to understand the influence of process parameters (applied load, sliding velocity, sliding distance) on the dry sliding wear rate and co-efficient of friction. A 5-level 3 parameter central composite design was developed using response surface methodology considering applied load (10-50N), sliding velocity (1-3 m/s) and sliding distance (500-2500 m) as input parameters. Dry sliding experiments were performed on pin-on-disk tribometer at ambient conditions. Significance tests, Analysis of Variance and confirmation experiments were done to check the accuracy of generated regression model. Generated surface plots revealed wear rate to be increasing as applied load and sliding distance increases and decrease as sliding velocity increases. Worn surface analysis performed revealed formation of deep grooves at high load, MML formation at high velocities and heavy delamination and particle pull-out at high sliding distances.
Electrical Characterization of Tailored MoS2 Nanostructures
Authors: Viswan Gauthami , Reshmi S. , Sachidanand P S , Mohan Manu , Bhattacharjee K.
Published: December 2019

We try to understand the photocurrent generated in the tailored Molybdenum disulphide (MoS2) nanostructures which were exfoliated from bulk MoS2 powder by a simple liquid phase exfoliation followed by microwave treatment. Sonication and microwave treatment led to the formation of mostly hollow tailored MoS2 nano-rods and nano-spheres which consist of more metallic 1T phase than semiconducting 2H phase. In this paper the interaction of light with these nanostructures and the generation of photocurrent is of peer interest. Confinement of photon in the hollow nanostructures could be very promising to derive photocurrent which can have applications in various optoelectronic devices.
Comparative study on performance of controlling geometric nonlinearity of laminated smart composite plate using piezoelectric fiber reinforced composite & active fiber composite material
Authors: Khadakbhavi Vishwanath , Ashok M H , Shivakumar J , Pujari Sanjay , Nandurkar Santosh
Published: December 2019

The present work highlights on comparative investigation for the performance of active constrained layer damping treatment using PFRC and AFC patch material for controlling the nonlinear transient vibrations of laminated composite plate. In this case for making the constraining layer of the ACLD treatment for PFRC and AFC patch material is used. For modelling of ACLD in the time domain Golla-Hughes-McTavish (GHM) method is used. The Von Karman type non-linear strain displacement relations along with a simple first-order shear deformation theory are used for deriving this electromechanical coupled problem. A finite model in 3-dimensions has been developed for smart composite plate integrated with the ACLD treated patches of PFRC and AFC. The results of both the cases have been compared and it has been found that the improved performance of AFC patch over the PFRC in subsiding the transient nonlinear vibrations of symmetric cross ply laminated composite plate.
Performance analysis of the solar photovoltaic thermal system using phase change material
Authors: Singh Rahul , Kumar Anil , Yadav Anshul
Published: December 2019

This study presents the experimental analysis of photovoltaic thermal system and calculations for percentage electrical efficiency gained and thermal energy. Photovoltaic cells are sensitive to temperature and its performances decrease with increasing temperature. To increase the performance of the photovoltaic panel, a phase change material cum water heating arrangement is attached to the photovoltaic panel. To reduce the cell temperature, paraffin wax (phase change material) is used in the experiment as a heat storage medium. A copper tube is attached to the containment box filled with phase change material. Water is heated through paraffin wax when it flows through the copper tube. The photovoltaic thermal system has a dual benefit over photovoltaic system i.e. it improves electrical efficiency and produces thermal energy simultaneously. It was concluded from the experimental work that percentage of electrical efficiency gained from the photovoltaic thermal system is 1.12% in comparison with polycrystalline silicon photovoltaic panel of model DDS50M at ambient temperature. The maximum reduction in cell temperature and the average thermal energy produced is 8.5°C and 25.45 J/min respectively.
I-V characteristics and Room Temperature Hall Measurement of CdTe Nano-rods Synthesized by Hydrothermal Method
Authors: Gumaste Meera Ramachandra , Kulkarni Gururaj Anand , Anuradha K N
Published: December 2019

CdTe Nano-rods have been synthesized using Hydrothermal method. For the confirmation of formation of CdTe in nano metric dimension XRD technique is employed. The diameter of CdTe nano-rods is calculated to be 35.04 nm. SEM image reveals that nano CdTe possess rod shaped morphology. The compositional data is collected with EDAX spectra. Successful capping of thioglycolic acid (TGA) on the surface of CdTe nano-rods is well endorsed by FTIR spectroscpoy technique. Band gap is calculated to be 1.65eV from UV-Visible absorption spectra. I-V characteristics of the CdTe nano-rods showed a linear symmetrical variation at room temperature. This was due to the high crystallinity and homogeneous powder sample of CdTe nano-rods. The higher value of mobility of the order of 1.1264 X 103 cm2/V-s of the as synthesized CdTe nano-rods reveals moderate grain boundaries and less structural defects. Hence compared to bulk CdTe, nano-structured CdTe materials are more ordered in structure and hence improved crystallinity. Room temperature Hall meaasurement employing Van Der Pauw method indicates high resistivity of the order of 107 Ω cm and the as synthesized nano-rods are of p-type material.
Design and Fabrication of Grass Cutting and Water Spraying Rover
Authors: Subrahmanyam R.V. , Vikas N , Prashanth B.N.
Published: December 2019

In this age of robotics and automation, it comes as a surprise to us that the most basic dull tasks such as gardening are still done in majority by humans. Even the simplest jobs of trimming the grass have become only faux-automated - there are machines, but you always need a person to run around the field with that. We believe that humans should naturally move on to tasks that utilize their potential the most - tasks that involve creativity, imagination and innovation. Considering these aspects and came up with the automatic trimming and water spraying rover. Combination of both cutting grass and water spraying makes the project more interesting, moreover both the tasks can be performed simultaneously or both operations can be done at different situations according to the operator. Input will be given through Arduino and accordingly the rover moves. Trimming and irrigation of fields and gardens are among the most mundane, monotonous tasks known to man. Along with being boring and uninspiring to the doers, these separately conducted tasks also increase the total time of execution, and the costs involved. Not only do they kill the creativity of the people, they also cost a fortune given the increasing costs of manual labour, not to forget all the imperfections and errors that are induced in the project.
Improved bounds on the Radio degree of a cycle
Authors: Vanam Radha Ramani , Meera K. N. , Dhanyashree
Published: December 2019

A labeling f : V (G) → Z
+ such that |f(u)−f(v)| ≥ diam(G)+1−d(u, v) holds for every pair of vertices, u, v ∈ V (G), is called a radio labeling of a graph, G. The radio degree of a labeling, f : V (G) → {1, 2,… |V (G)|} in a graph, was defined by the same authors as the number of pairs of vertices u, v ∈ V (G) satisfying the condition |f(u) − f(v)| ≥ diam(G) + 1 − d(u, v) and was denoted by rdeg(f). The maximum value of rdeg(f) taken over all such labelings was defined as the radio degree of the graph, denoted by rdeg(G). The radio degree of some standard graphs like paths, complete graphs, complete bipartite graphs, wheel graph and fan graph was completely determined and a lower bound on the radio degree of cycles was obtained. In this paper, the authors have obtained better bounds on the radio degree of a cycle.

AMS Subject Classification number: 05C78, 05C12, 05C15
Drug Entrapment Efficiency of Silver Nanocomposite Hydrogel
Authors: Giridhar Reddy S. , Thakur Amrita
Published: December 2019

Silver nanocomposite hydrogel (SNH) with biodegradable polymers, sodium alginate and sodium lignosulphonate was synthesized employing principles of green chemistry for possible application in the field of controlled drug release. One of the factor that determines the release of drug from blend is the quantity of drug present/trapped inside the polymer network. The entrapment of drug in the polymer matrix depends upon the stability of matrix and interaction between the drug and the matrix. In the present study effect of presence silver nanoparticles in the polymeric matrix on the Drug Entrapment Efficiency (DEE) for the drug ciprofloxacin (CPX) was investigated. The drug entrapment efficiency for CPX loaded beads of SA/LS was calculated for similar conditions, to evaluate the effect of silver nanoparticles. Experimental results confirmed role of crosslinking and presence of silver nanoparticles on the stability of SNH and its entrapment efficiency. Observations indicate that the drug entrapment is more for the SNH as compared to the blend. Presence of silver nanoparticles help stabilize the polymer matrix, improves binding inside the matrix, which leads to the better drug entrapment.
Prediction of Cutting Forces Experimentally in End Milling Process Using Inverse Analysis
Authors: Patil Ratan A , Gombi S L
Published: December 2019

Milling is a versatile manufacturing process which is used in machining many types of complex geometry parts, which has become the prior subject for many research studies. This paper provides study on cutting forces on end milling during machining. The study deals with the indirect measurement of cutting forces during machining using frequency response function (FRF). The problem of determining the unknown force acting on a body or a structure is the inverse problem. The cutting forces acting on a tool can be estimated by the responses measured at different points when the tool comes in contact with the work piece. The accuracy of the method can be improved by using singular value decomposition method and Moore Penrose pseudo inverse method. The experimental method results in better identification of cutting force which helps in optimum design and development of cutting tools. Statistical analysis helps in knowing the level of significance of the proposed method.
A Comparative Study on Mechanical Properties of Kenaf Fiber-Reinforced Polyester Composites Prepared by VARI, RTM and CM Techniques
Authors: Suresh Babu A , Gowthamraj S , Jaivignesh M
Published: December 2019

This work aims at comparing the mechanical properties of composite laminate fabricated by three different fabrication processes. Kenaf fiber polyester composite laminates were fabricated by compression moulding technique, Vacuum assisted resin infusion process (VARI) and Resin transfer moulding process (RTM). Vacuum assisted resin infusion (VARI) process bridges the gap between labour intensive compression moulding process and capital intensive Resin transfer moulding (RTM) process. The mechanical properties such as tensile, flexural and impact behaviour were studied. Vacuum assisted resin infusion process showed improved tensile and flexural strength as compared to resin transfer moulding process and compression moulding (CM) process. On the other hand, impact strength of VARI composites is slightly lower than that of RTM and CM composites. From the study, it was found that mechanical properties increase with increase in fiber content and uniform distribution of resin in the matrix. The void content and water absorption properties were evaluated and found to be maximum for the compression moulded composites.
An Ant Colony and Simulated Annealing Algorithm with Excess Load VRP in a FMCG Company
Authors: Srinivas Rao T
Published: December 2019

Fast moving consumer goods pose a major research problem as the objective is to reach the customers in an efficient manner. The delivery of goods to consumers must reach quickly without any hurdles. We assume that the FMCG companies have multiple number of warehouse hubs to reach its vast majority of consumers. Sometimes a single vehicle may not be enough to complete the tour, hence we may require another small vehicle to reach the small set of customers. The above problem has been modelled as a supply chain vehicle routing model. In our paper we have used ant colony and simulated annealing algorithm to discuss the above problem and compare their efficiencies.
Experimental Investigations on Rectangular Dielectric Resonator Loaded on a Microstrip Line
Authors: Narayanan Vipin , Sahajan Arjun , Menon Sreedevi K
Published: December 2019

This paper is an analysis of the filter characteristics of a rectangular dielectric resonator (DR) loaded on a Microstrip Line (MSL). Position of the rectangular DR on the Microstrip Line is optimized for best performance of the filter and different orientations of the dielectric resonator are tried out for finding the optimized orientation and position. For efficient coupling between MSL and DR a metallic patch is provided at the bottom of dielectric resonator with the same dimension as the surface touching the feedline. Experimental studies carried out ascertain, the proposed DR loaded on MSL is an effective filter.
Carbon Quantum Dot-Polypyrrole Nanocomposite for Supercapacitor Electrodes
Authors: Sagar Mittal Shiva , Ramadas Gouri , Vasanthmurali Nandika , Madaneshwar V S , Sathish Kumar M , Kothurkar Nikhil K
Published: December 2019

A CQD-polypyrrole composite was developed as a supercapacitor electrode material. Carbon quantum dots (CQDs) were synthesized using citric acid as carbon precursor. The CQDs were incorporated in a polypyrrole matrix by dispersing them during the in-situ polymerization of pyrrole. The structure and morphology of the composite were characterized using FT-IR, XRD, TEM. Cyclic voltammetry and galvanostatic charge-discharge studies were performed using a three-electrode system to understand the electrochemical behaviour of the sample. The composite showed a 33% increase in the specific capacitance as compared to neat polypyrrole.
Determination of the dislocation-based mechanism(s) responsible for the anomalous ductility of a class of B2 intermetallic alloys
Authors: Agnew S R , Ungar T
Published: December 2019

A class of stoichiometric, ordered MR alloys (where M denotes a metal and R either a rare earth or group IV refractory metal) with B2 (CsCl) crystal structure, were discovered to possess anomalous ductility by researchers at Ames Laboratory in the early 2000’s. Despite active research on the topic for over 15 years, a holistic explanation for the anomalous ductility of these metal alloys has not yet been accepted by the scientific community. The reason for this appears to be a failure to account for all relevant length scales. Researchers either focus on theatomisticlength scale relevant to dislocation core structures, themicroscopiclength scale of dislocations and dislocation ensembles, themesoscopiclength scale of grains and their interactions, or themacroscopicscale of mechanical testing samples with millimetre dimensions or larger. Focused studies at each of these length scales have provided essential, but insufficient information to provide a complete answer to the question. The insight provided by in-situ diffraction studies, along with crystal plasticity modelling as an interpretive tool, and a novel grain-by-grain line profile analysis technique for assessing dislocation densities in polycrystals is highlighted. In addition to the primary <100> dislocations, which are most easily activated in all of these anomalous MR alloys, the results show that dislocations with large Burgers vectors (e.g., <110> and <111>) are present in large numbersbeyond a transitionin the strain hardening response. The motion of these large Burgers vector dislocations is experimentally observed to occur at stress levels consistent with atomistic modelling predictions of the Peierls resistance and simultaneously provides a satisfying explanation for the anomalous ductility and other experimental results.
Understanding the evolving state of deforming polycrystals using synchrotron x-rays
Authors: Miller Matt , Budrow Chris , Long Tim , Obstalecki Mark
Published: December 2019

The multiscale nature of irreversible processes like plasticity make them particularly challenging. One must be looking everywhere, all the time to gain a predictive understanding of plasticity–related processes such as fatigue crack initiation. High energy (HE) synchrotron x-ray diffraction is a unique tool for characterizing the state of an entire aggregate of metallic crystals with sub-crystal resolution. Combined with in situ loading, HE x-ray diffraction provides experimental hope for characterizing the conditions leading to the initiation of a crack. In this work, we conducted a HE x-ray diffraction experiment on a commercially pure copper sample subjected to in situ cyclic loading at the F2 Station at the Cornell High Energy Synchrotron Source (CHESS). We observed that the evolution of lattice orientation distributions within each crystal evolved as the specimen was loaded through complete fatigue cycles. We defined a “size” of these orientation clouds, which we called

Θ
¯

. Changes in

Θ
¯

are related to the plasticity-induced state of each crystal. We saw significant evolution of the

Θ
¯

distributions as the sample went through cycle 2. By cycle 256, the evolution of the

Θ
¯

distribution was significantly reduced - consistent with the saturation of cyclic hardening that we see on the macroscale. We also saw that the 40 crystals with the largest values of

Θ
¯

in the first half cycle had a larger amount of

Θ
¯

accumulation on average over the 256 cycles than the rest of the crystals in the aggregate.
Following Microstructures during Deformation: In situ X-ray/Neutron Diffraction and HRDIC
Authors: Polatidis E , Sofinowski K , Hsu W-N , Swygenhoven H Van
Published: December 2019

The mechanical behavior of three engineering materials is studied employing in situ deformation methods. The study covers metastable austenitic steels with different stacking fault energies during multiaxial loading, a Ti-6Al-4V alloy processed by electron beam melting during uniaxial deformation and a commercial nanocrystalline NiTi alloy during multiaxial deformation. The experimental results obtained by in situ X-ray or neutron diffraction elucidate the load transfer and phase transformation mechanisms, information that is averaged over a relatively large volume containing a statistically representative number of grains. Complementary in situ high resolution digital image correlation allows details to be revealed regarding the localized strain accommodation and slip activity with a sub-grain spatial resolution. It is demonstrated that the synergy of the different length-scale investigations provides a better understanding of the complex relationship between microstructure and deformation behavior in these materials.
Rich multi-dimensional correlative imaging
Authors: Withers Philip J , Burnett Timothy L
Published: December 2019

The use of microstructural design to tailor materials properties has increased sharply in recent years. In parallel the number and the capability of techniques able to characterise materials microstructures has increased sharply too providing structural, chemical and crystallographic information. Here we examine how correlated 3D, 4D (3D + time) and multi-dimensional imaging enable a much richer picture to be built up of a materials microstructure. We look at how a data-centric approach can support the use of materials informatics, digital twinning and machine learning to accelerate the design of new materials systems and to optimise the manufacturing of established ones. However for this to happen we need to develop ways to digitally fingerprint the microstructural images and maps we collect such that they can be incorporated into machine learning schemes. Through the use of case studies (multimodal imaging) we look at correlative imaging across scales, across time (the dilation of electrode materials in lithium batteries during discharging and fast corrosion of magnesium), as well as across multiple modalities (butterfly defects in bearings steels and the sintering and recrystallization of powders). These demonstrate how different techniques can come together to provide complementary aspects of the bigger picture.
An efficient method to improve the spatial resolution of laboratory X-ray diffraction contrast tomography
Authors: Fang H , Jensen D Juul , Zhang Y
Published: December 2019

Lab-based diffraction contrast tomography (LabDCT) has recently enabled nondestructive 3D characterization of the crystallographic orientations and grain morphologies in bulk materials. Despite the wide accessibility and availability of lab-based X-rays, the current spatial resolution of LabDCT is only about 20 μm and has to be improved to make this technique a more versatile tool. Conventional LabDCT takes advantage of the Laue focusing effect, i.e. the diffracted beam from a sample illuminated by an incoming polychromatic beam, is focused when the source and the detector are symmetrically positioned. In this study we have investigated the possibility of increasing the spatial resolution of LabDCT by placing the detector at a distance beyond that required for Laue focusing. We first developed a forward projection simulation tool to elucidate the effects of placing the detector at a larger distance. Next, we performed LabDCT measurements on a partially recrystallized pure aluminum sample at different sample-to-detector distances. The results show that the diffraction spots can be magnified by a factor of about three compared to the current LabDCT setup. The benefits and limitations resulting from increasing the sample-to-detector distance are discussed.
Statistics and Reproducibility of Grain Morphologies and Crystallographic Orientations Mapped by Laboratory Diffraction Contrast Tomography
Authors: Sun Jun , Oddershede Jette , Bachmann Florian , Bale Hrishikesh , Lauridsen Erik
Published: December 2019

Laboratory diffraction contrast tomography (LabDCT) enables a user to reconstruct 3D grain maps of polycrystalline materials non-destructively. For each grain, the morphology and crystallographic orientation, as well as derived properties such as grain boundary properties can be determined. Through two application examples this paper demonstrates the capabilities and potential of the current LabDCT implementation. Firstly, for well-annealed grain structures the reproducibility of LabDCT for more than 95% of the grains was found to be 5 μm on grain center-of-mass positions and 0.02° on orientations, while 90% of the grain boundary locations are determined with an accuracy better than 4 μm. The second example highlights the available statistics on thousands of grains, as well as the complementarity between LabDCT and absorption contrast tomography, readily available due to the integration of LabDCT on a commercial X-ray microscope
Ultrafine-grained Tungsten by High-Pressure Torsion – Bulk precursor versus powder processing route
Authors: Wurmshuber M , Doppermann S , Wurster S , Kiener D
Published: December 2019

The continuous enhancements and developments in the field of power engineering, as well as the uprising of nuclear fusion technology, demand novel high performance materials featuring exceptional strength and damage tolerance as well as durability in harsh environments. Ultra-fine grained bulk materials fabricated by high-pressure torsion, exhibiting a grain size less than 500 nm are promising candidates for these applications. Tungsten, the material of choice for plasma-facing materials in fusion reactors, is expected to exhibit even more enhanced properties by precise doping with impurity atoms, strengthening grain boundary cohesion. In order to allow this meticulous control of chemical composition, in-house mixing of the raw material powders is preferable to use of commercially available alloys. Several challenges arise in powder processing of tungsten via high-pressure torsion, originating in the intrinsic strength and high melting point of the material, and in the affinity of the powder to oxygen. Strategies to overcome these problems will be addressed in this work. Furthermore, we compare ultra-fine grained tungsten produced from a bulk precursor to that from the developed powder approach regarding microstructural features, hardness and rate-sensitive properties. The powder route showed promising and widely comparable results to the material processed from bulk tungsten, rendering it an effective way for fabricating ultra-strong tungsten, while keeping the additional ability to accurately control chemical composition and tailor grain boundary segregation states.
A unified model for microstructural coarsening of deformed metals
Authors: Yu T
Published: December 2019

In this work the kinetics of continuous coarsening of deformation microstructures are analysed. The coarsening examples span a large range in structural scale and driving force, including subgrain growth in a deformed subgrain structure, uniform coarsening in a deformed lamellar structure, and grain growth in a deformed nanocrystalline structure. The unified coarsening model for deformation microstructures considers the change of the apparent activation energy during coarsening and successfully describes the kinetics in each of the given coarsening examples. It is also found that the increase in the apparent activation energy dominates the coarsening kinetics and leads to a significant decrease in the coarsening rate as coarsening proceeds.
Coarsening in nanocrystalline thin films: A 4D problem
Authors: Öncü A. , Zöllner D.
Published: December 2019

Materials properties of polycrystalline solids depend strongly on the microstructure. Hence, investigating grain microstructures as they change during grain growth, e.g., by thermal annealing, is of utmost importance. Historically, this has been done by optical microscopy yielding only a two-dimensional characterization. Consequential problems have long been recognized. In particular, a two-dimensional section through a three-dimensional polycrystal yields a rather poor idea about the true size and form of the individual grains, and therefore of the microstructure, and in addition, such a section represents only a snapshot in time and does not give any clues about structural changes during grain growth. In the present study, we investigate coarsening in nanocrystalline thin films using a modified three-dimensional Potts model. By taking the increased importance of higher order grain boundary junctions, i.e. triple lines, at smaller grain sizes into account, it is shown that the microstructure, as well as the associated growth kinetics, undergo distinct changes during coarsening.
The strength of the hull on a high longitudinal wave
Authors: Suvorov Vladimir , Bahrami Mohammad Reza
Published: December 2019

The paper presents the method for calculating the strength of the ship vessel on the longitudinal wave, based on the modern theory of the beam and computer mathematics. It consists of two parts, which are the determination of hydrodynamic loads on the hull during the passage of a wave and the calculation of the stress-strain state caused by the ship vessel as a beam. The main feature of the technique is that the loads and deflection are considered simultaneously, which was made possible by computer mathematics. The developed method allows; increasing the accuracy of calculations of ship hulls for durability, has a relatively low cost, and does not require expensive software.
Three-dimensional vibrations of wind turbines
Authors: Andriushchenko Ekaterina , Meshkov Aleksandr
Published: December 2019

In this paper authors consider three-dimensional vibrations of a wind energy farms (WEF) of tower type VTR 50 Arctic. Low-frequency vibration of a WEF composed of a tower and rotor is considered in the out of balance condition. The method of analysis is based on the theory of mechanical oscillations and the theory of elastic shafts. We consider the tower as a shaft and the rotor as a rigid body. Using the Lagrange’s equations for elastic structures in combination with computer simulation provides for the novelty and efficiency of the suggested method. The unique nonlinear equation is deduced and solved using the Wolfram Mathematica.
Vibration analysis of skidding tractor with an operator during raising–lowering a tree
Authors: Bahrami Mohammad Reza , Wasilewski Mark , Abed Salam Ahmed
Published: December 2019

The aim of this article is to develop mathematical models that help at the design stage of design documentation for a skidder to determine the upcoming dynamic loads on the machine, the vibration effect on the machine and the operator, and scientifically based parameters to ensure their reduction. Vibration analysis and prediction of the skidding tractor with an operator allows predicting adverse events, prevent accidents, avoid costly and dangerous experiments, as well as optimize the design and operating modes. A particularly important degree of vibration loads affects the performance and health of the operator. The constant long-term effect of vibrations leads to increased operator fatigue and an increase in the number of errors in control. As a result, operator productivity significantly reduced. Baseline data that used in this article is related to the skidding trailer tractor TB-1M. So the results of this research may use as the foundation of future works for omitting vibration influence on the operator by designing active and smart dynamic vibration absorber for a different type of tractors. In addition, the effect of sitting stiffness and loading on the operator-tractor system have been investigated.
Area determination of correct operation of the vibrofuge
Authors: Krokhmal Vladislav , Klyukin Valeriy
Published: December 2019

The object of the study is a centrifuge, on the rotor of which a pneumatic spring with a mechanical vibrator is fixed. The operation of the pneumatic spring during rotation of the centrifuge rotor and the operation of a mechanical vibrator with varying plant parameters is analyzed. Identified parameters that significantly affect the operation of the plant. The areas of parameters in which the correct operation of the plant is observed are found.
The use of artificial intelligence to control the processes of welding and direct arc growth under the influence of disturbing factors
Authors: Pereverzev A.E. , Ivanova I.V. , Maystro Alexey , Zarubin I. A. , Panfay Wan
Published: December 2019

We develop a method to improve the quality of welded joints and process performance in arc welding and direct arc growing under the influence of disturbing factors based on the use of artificial intelligence.
Optimization of the design of the plasma torch for using gas fluxes
Authors: Goshkoderya M E , Kovalev M A , Zarubin I A , Zhugarev N A , Panfay Wan
Published: December 2019

The paper presents the results of plasma torch development and gas fluxes using possibility in plasma welding process. As part of the work, existing plasma torches were analyzed in order to identify opportunities for their modernization. The literature data was analyzed for identifying the optimal design of the plasma torch. During the study of literature data, it was found that the diameter of the nozzle tip has a great influence on the plasma welding process. Therefore, it was decided to model the processes occurring in the plasma torch using tips with different diameter sizes. Parameters that effects on the stability of plasma welding process were presented. Possible and potential effective plasma torch tip designs were proposed. The model of the behavior of argon in a plasma torch was constructed, which made it possible to draw conclusions about the optimum diameter of the plasma torch tip. Also, was shown the effect of the diameter of the plasma torch on the behavior of plasma gas.
Influence of the cross-sectional area of the shear layer on the distribution of the zones of tension and compression in replaceable cutting inserts
Authors: Kireev V.V.
Published: December 2019

As a result of the conducted researches it is established that with a progressive cutting scheme, the dangerous tensile stresses in the cutting carbide plates are significantly reduced. It was found that when using a worm cutter with a progressive cutting circuit, the dangerous tension of the tensile stresses on the front surface of the carbide plates is greatly reduced. Analysis of the obtained main stresses in the cutting wedge showed that the cutting edge experiences tensile stresses on the front surface, and compression on the front surface. It is established that the cutting element of the milling cutter undergoes an alternating asymmetrical nature of loading, accumulating cyclic fatigue in the main cutting edge.