M. Adamczyk, A. Lisińska-Czekaj, L. Kozielski, R. Zachariasz, R. Nowak and D. Czekaj
The mechanical properties of the pure as well as vanadium modified BaBi2Nb2O9 ceramics have been studied in macro and nano-scales using three different methods. Specifically for…
Abstract
The mechanical properties of the pure as well as vanadium modified BaBi2Nb2O9 ceramics have been studied in macro and nano-scales using three different methods. Specifically for macro-scale, ultrasonic velocity and internal friction were employed to evaluate the Young modulus (E), whereas for nano-scale the nanoindentation method was a very useful tool to obtain the elastic modulus and hardness. These results reveal the strong influence of vanadium admixture on mechanical properties of the discussed material. In the case of modified ceramics the value of Young modulus increases, which is probably connected with the decreasing of the number of defects. Moreover, the described results show the significant differences in mechanical properties measured on nano and macro-scale. It is concluded that the knowledge of the mechanical properties of the ceramic material is complete only when we take into account both the macro and nano-scale.
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Bartlomiej Melka, Wojciech P. Adamczyk, Marek Rojczyk, Marcin L. Nowak, Maria Gracka, Andrzej J. Nowak, Adam Golda, Ryszard A. Bialecki and Ziemowit Ostrowski
The purpose of this paper is the application of the computational fluid dynamics model simulating the blood flow within the aorta of an eight-year-old patient with Coarctation of…
Abstract
Purpose
The purpose of this paper is the application of the computational fluid dynamics model simulating the blood flow within the aorta of an eight-year-old patient with Coarctation of Aorta.
Design/methodology/approach
The numerical model, based on commercial code ANSYS Fluent, was built using the multifluid Euler–Euler approach with the interaction between the phases described by the kinetic theory of granular flow (KTGF).
Findings
A model of the blood flow in the arches of the main aorta branches has been presented. The model was built using the multifluid Euler–Euler approach with the interaction between the phases described by the KTGF. The flow and pressure patterns, as well as the volumetric concentration of the blood components, were calculated. The lumped parameter model was implemented to couple the interaction of the computational domain with the remaining portion of the vascular bed.
Originality/value
The multiphase model based on the Euler–Euler approach describing blood flow in the branched large vessel with a three-element Windkessel model in the coarcted geometry was not previously described in the literature.
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L. Kozielski, M. Adamczyk, A. Lisińska-Czekaj, D. Czekaj, R. Zachariasz, M. Pawełczyk and M. Pilch
Gaining the precise control over the matter at the nanometre scale is the main leitmotif in a majority of nanoscience oriented research measurements nowadays. The availability of…
Abstract
Gaining the precise control over the matter at the nanometre scale is the main leitmotif in a majority of nanoscience oriented research measurements nowadays. The availability of new advanced tools, as a nanoindentation technique, for evaluation of the mechanical properties, seems to be prerequisite for exploitation of the dramatic development in nanoscience and meeting the emerging needs of the industries in new electronic applications. The nanoindentation technique was applied to evaluate the elastic modulus and hardness values as a function of indentation depth. However, in the presented experiment the nanoscale mechanical properties of BaBi2Nb2O9 ceramics have been characterized and compared with the macroscale measurements with macroscale method with the implementation of ultrasound techniques. A draw conclusion indicates that expensive nanoscale characterisation presented here is not fully consisted with the microscale. The reasons of such state of things are widely discussed.
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Monika Duchna, Iwona Cieślik, Alexander Kloshek, Bogusława Adamczyk-Cieślak, Magdalena Zieniuk, Dorota Moszczyńska and Jarosław Mizera
The purpose of this paper is to obtain high-temperature-resistant material with high density and to conduct microstructural investigations of 3D-printed Ni-based alloy 713C…
Abstract
Purpose
The purpose of this paper is to obtain high-temperature-resistant material with high density and to conduct microstructural investigations of 3D-printed Ni-based alloy 713C specimens.
Design/methodology/approach
High-density specimens of Ni-based alloy 713C were obtained by the optimizing selective laser melting (SLM) process parameters and an X-ray diffraction (XRD) analysis confirmed the occurrence of γ and γ′ phases and the presence of carbides in the SLM-manufactured Ni-based alloy 713C. The analysis of electron backscatter diffraction (EBSD) studies suggested a preferred 〈100〉 direction orientation and low angle misorientation for the SLM specimens.
Findings
The high-density specimens of Ni-based alloy 713C were obtained by the optimized SLM process parameters. XRD analysis confirmed the presence of γ and γ′ phases and carbides in the SLM-manufactured Ni-based alloy 713C. Analysis of EBSD studies suggested a preferred 〈100〉 direction orientation and low angle misorientation for the SLM specimen.
Originality/value
In this study, 3D-printed Ni-based alloy 713C with a high density of 99% was obtained for the first time, to the best of the authors’ knowledge.
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Laxmidhar Behera, Siddhartha Agarwal, Tushar Sandhan, Pratibha Sharma, Ashish Kumar, Ayush Ranjan, Sidhartha Watsa, Atul Singh and Jyothi Swaroop Kasina
The unmanned ground vehicle (UGV) described in this manuscript is a robot designed by the authors to map the underground mine environments. The UGV works to develop a…
Abstract
Purpose
The unmanned ground vehicle (UGV) described in this manuscript is a robot designed by the authors to map the underground mine environments. The UGV works to develop a computational intelligence-based cyber-physical system (CPS)-based analytical framework for mining operations. The UGV demonstrated excellent semi-autonomous navigation capabilities in the absence of GNSS signals. The UGV has a suite that works in unison to provide relevant information. These sensors are integrated to form a robust sensor fusion-based architecture, creating a CPS with a wide range of capabilities such as data acquisition and navigation in challenging underground environments. UGVs can be used to enhance the efficacy of safety inspections, rescue during underground emergencies and assist miners in hazardous conditions.
Design/methodology/approach
In this research, an UGV was constructed whose operations are enabled by sensors including a D415i Red Blue Green (RGB) depth camera, a LiDAR, a FLIR C5 infrared camera and smart air quality sensors. This sensor fusion-based architecture forms a CPS. Data obtained remotely are processed by deep learning algorithms to achieve overall capabilities such as real-time image analysis for miner identification, object detection, posture analysis and identifying threats of roof falls and overhangs. Simultaneous localization and mapping (SLAM) algorithms create a 3D map, facilitate autonomous navigation and build a decision support system for delivering mine rescue support.
Findings
The aim of this study is to include this capacity in training situations when it has been validated and authorized by the Directorate General of Mines Safety (DGMS) Indian government regulatory agency for safety in mines and oil fields. The longwall demo mine, at IIT (ISM) is being used as the site of the first operations. Once approved by the respective enforcement agencies, this technology and the accompanying rescue and training process can be used in underground operations.
Originality/value
In fact, this paper is the first attempt at remotely operated UGVs based on CPSs, the CPS–UGV in Indian mine conditions, so as to revolutionize Indian mines based on the idea of Industry 4.0.
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Emmanuel Okoro Ajah, Chidi Ononiwu and Charles Nche
In pursuit of socio-economic growth, scholars and policymakers in emerging economies continues to show interest in understanding technology-based start-up (i.e. tech start-up…
Abstract
Purpose
In pursuit of socio-economic growth, scholars and policymakers in emerging economies continues to show interest in understanding technology-based start-up (i.e. tech start-up) emergence, to help mitigate persistent failure experienced during commercialization. Howbeit, some scholars lamented that extant studies that investigated tech start-up emergence are mostly fragmented, because they focus on specific event/sub-process in tech start-up gestation. Thus, this study aims to conduct a systematic literature review to discover, harmonize and develop a framework that describes the interaction among varying dimensions of events/sub-processes that characterizes tech start-up emergence in an emerging economy.
Design/methodology/approach
To conduct this study, the authors engaged a concept-centric systematic literature review. Having developed a search protocol, the authors searched through information systems database, and other relevant discipline databases, to select relevant articles for review.
Findings
The systematic review revealed various dimensions of events (i.e. opportunity discovery and selection, team formation and domain consensus, bootstrapping and the development of minimum viable product and market experimentation feedback) that are critical to tech start-up emergence. Most prior studies are isolated, as they focus their investigation on specific event. Thus, from this review, the authors developed a framework harmonizing various dimensions of events characterizing emergence of a viable tech start-up.
Originality/value
The researchers conducted this study in response to lingering call for harmonized study that provides in-depth description of how different dimensions of events interact and characterize tech start-up emergence. Consequently, the study resulted in a descriptive framework. Furthermore, the findings highlight some practical implications and proposes new study directions as future research agenda for scholars interested in tech start-up emergence.
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Ahmad Fikri Mustaffa and Vasudevan Kanjirakkad
This paper aims to understand the aerodynamic blockage related to near casing flow in a transonic axial compressor using numerical simulations and to design an optimum casing…
Abstract
Purpose
This paper aims to understand the aerodynamic blockage related to near casing flow in a transonic axial compressor using numerical simulations and to design an optimum casing groove for stall margin improvement using a surrogate optimisation technique.
Design/methodology/approach
A blockage parameter (Ψ) is introduced to quantify blockage across the blade domain. A surrogate optimisation technique is then used to find the optimum casing groove design that minimises blockage at an axial location where the blockage is maximum at near stall conditions.
Findings
An optimised casing groove that improves the stall margin by about 1% can be found through optimisation of the blockage parameter (Ψ).
Originality/value
Optimising for stall margin is rather lengthy and computationally expensive, as the stall margin of a compressor will only be known once a complete compressor map is constructed. This study shows that the cost of the optimisation can be reduced by using a suitably defined blockage parameter as the optimising parameter.
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The purpose of this self-study is to analyze my experiences learning in Poland, the country where Nazis imprisoned and murdered my family. I share findings from multiple museum…
Abstract
Purpose
The purpose of this self-study is to analyze my experiences learning in Poland, the country where Nazis imprisoned and murdered my family. I share findings from multiple museum locations, including implications for history teachers, teacher educators and visitors to Holocaust museums.
Design/methodology/approach
I participated in a ten-day professional development seminar designed for American teachers to visit Poland. To allow for self-study after the trip, I maintained a reflexive journal and photographic records of each day I was in Poland. I analyze these data in conjunction with publicly available data from the museums and historical sites I visited in Poland.
Findings
The findings suggest that teachers can face many challenges when learning in a land of traumatic absences. Many challenges stem from the absences of buildings and survivors, as those may be integral to place-based learning. Testimonies and first-person accounts may ameliorate these challenges for teachers engaging in place-based learning. Additionally, teachers may use these accounts to bring a pedagogy of remembrance from Poland to their classrooms.
Originality/value
This study is not under review with another journal.
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Wit Stryczniewicz, Janusz Zmywaczyk and Andrzej Jaroslaw Panas
The paper aims to discuss the inverse heat conduction methodology in solution of a certain parameter identification problem. The problem itself concerns determination of the…
Abstract
Purpose
The paper aims to discuss the inverse heat conduction methodology in solution of a certain parameter identification problem. The problem itself concerns determination of the thermophysical properties of a thin layer coating by applying the laser flash apparatus.
Design/methodology/approach
The modelled laser flash diffusivity data from the three-layer sample investigation are used as input for the following parameter estimation procedure. Assuming known middle layer, i.e. substrate properties, the thermal diffusivity (TD) of the side layers’ material is determined. The estimation technique utilises the finite element method for numerical solution of the direct, 2D axisymmetric heat conduction problem.
Findings
The paper presents methodology developed for a three-layer sample studies and results of the estimation technique testing and evaluation based on simulated data. The multi-parametrical identification procedure results in identification of the out of plane thin layer material diffusivity from the inverse problem solution.
Research limitations/implications
The presentation itself is limited to numerical simulation data, but it should be underlined that the flake graphite thermophysical parameters have been utilised in numerical tests.
Practical implications
The developed methodology is planned to be applied in detailed experimental studies of flake graphite.
Originality/value
In the course of a present study, a methodology of the thin-coating layer TD determination was developed. In spite of the fact that it has been developed for the graphite coating investigation, it was planned to be universal in application to any thin–thick composite structure study.