scholarly journals State-of-the-art ultrasonic sensor designed to improve longwall production rates and operation safety

2021 ◽  
pp. 149-160
Keyword(s):  
State Of The Art ◽  
Ultrasonic Transducers ◽  
Structural Elements ◽  
Rock Falls ◽  
Longwall Panel ◽  
The Face ◽  
Path Measurement ◽  
Closed Structure ◽  
The Impact

The article describes issues related to the development of a sensor measuring the distance from the end of the shield support canopy to the face of the longwall panel. The sensor's task is to detect rock falls because in such a case, empty spaces in the coal seam below the roof are generated. The sensor is a part of the system which task is to predict unfavourable behaviour of the longwall roof affecting the continuity of mining. Due to an untypical workplace and difficult conditions prevailing there, it was not possible to use a typical sensor. The ultrasonic technique was used for this purpose. The next research stages related to the development of the sensor were described. Tests of various types of ultrasonic transducers, working at different parameters, were described. Only transducers with a closed structure were considered because they can operate in the presence of high dustiness and humidity. The sensor casing was adapted to a specific type of shield support. The installation location should not be accidental, as an additional hinged shield is mounted at the end of the canopy, which is an obstacle in the measuring track and can even completely cover it, making measurements impossible. The sensor is mounted close to the side edge of the shield support canopy using small free space, enabling a measurement. Structural elements of the canopy are obstacles in the measuring track and are a source of interference of the received signals. The ultrasonic transducers are built-in tubes, which direct the ultrasonic wave and amplify the received signals. The results of laboratory tests of the model of the path measurement sensor are presented. They describe the impact of analysed aspects, i.e. the type of transducers used, the structure of the surface that the wave is reflected from and the mechanical solutions on the quality of received signals. A prototype of a sensor installed on shield support is presented.

scholarly journals Smoothing additive manufactured parts using ns-pulsed laser radiation

2021 ◽  
Author(s):  
Florian Kuisat ◽  
Fernando Lasagni ◽  
Andrés Fabián Lasagni
Keyword(s):  
Surface Roughness ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Laser Source ◽  
Pulsed Laser Radiation ◽  
Current State ◽  
The Impact

AbstractIt is well known that the surface topography of a part can affect its mechanical performance, which is typical in additive manufacturing. In this context, we report about the surface modification of additive manufactured components made of Titanium 64 (Ti64) and Scalmalloy®, using a pulsed laser, with the aim of reducing their surface roughness. In our experiments, a nanosecond-pulsed infrared laser source with variable pulse durations between 8 and 200 ns was applied. The impact of varying a large number of parameters on the surface quality of the smoothed areas was investigated. The results demonstrated a reduction of surface roughness Sa by more than 80% for Titanium 64 and by 65% for Scalmalloy® samples. This allows to extend the applicability of additive manufactured components beyond the current state of the art and break new ground for the application in various industrial applications such as in aerospace.

scholarly journals Social isolation and quarantine in the COVID-19 pandemic: impacts on mental health and quality of population life

2021 ◽  
Vol 10 (2) ◽  
pp. e30510212535
Author(s):  
Gabriel Kiaro Leite Nunes ◽  
Karinne Alice Santos de Araújo ◽  
Thais Ranielle Souza de Oliveira ◽  
Marcelina da Conceição Botelho Teixeira ◽  
Ieler Ferreira Ribeiro ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Mental Health ◽  
Social Isolation ◽  
Negative Impact ◽  
Definitive Treatment ◽  
World Population ◽  
The World ◽  
The Face ◽  
The Impact

The COVID-19 pandemic brought about major changes in the lifestyle of the world population. Due to the lack of vaccines or a definitive treatment for disease, governments around the world have adopted social isolation and quarantine as methods to control the spread of the virus. Objective: Thus, the objective of this study was to discuss how social isolation and quarantine periods affected people's mental health and quality of life during the COVID-19 pandemic. Methods: An integrative literature review was carried out during the COVID-19 pandemic between March and September 2020, establishing the following guiding question: How did social isolation and quarantine affect the mental health and quality of life of the population in the COVID-19 pandemic? Results: The final sample consisted of nineteen (19) articles, two (2) addressed depression during the pandemic period, three (3) presented the pandemic and the relationship with sociodemographic aspects, five (5) analyzed mental health in the pandemic, four (4) reported the impact of COVID-19 on the population's style and quality of life and the last five (5) demonstrated the quality of human relationships and emotional aspects in the face of the pandemic. Conclusion: It was demonstrated that isolation and the quarantine period had a negative impact on the population's quality of life and long-term mental health.

scholarly journals Condensation of refrigerant R407C in multiport minichannel section

2016 ◽  
Vol 37 (4) ◽  
pp. 3-18
Author(s):  
Tadeusz Bohdal ◽  
Henryk Charun ◽  
Małgorzata Sikora
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Flow Resistance ◽  
State Of The Art ◽  
Condensation Process ◽  
Test Results ◽  
Pressure Drops ◽  
The Impact ◽  
Made In

AbstractAnalysis of the state of-the-art in research of refrigerant condensation in miniature heat exchangers, so-called multiports, was made. Results of refrigerant R407C condensation in a mini condenser made in the form of two bundles of tubular minichannels from stainless steel with an inside diameter 0.64 mm and length 100 mm have been presented. Two exchangers consisted of four minichannels and 8 minichannels have been investigated. The values of average heat transfer coefficient and frictional pressure drops throughout the condensation process were designated. The impact of the vapor quality of refrigerant and the mass flux density on the intensity of heat transfer and flow resistance were illustrated. A comparative analysis of test results for various refrigerants in both mini heat exchangers were made.

scholarly journals One-Way Nested Regional Climate Simulations and Domain Size

2005 ◽  
Vol 18 (1) ◽  
pp. 229-233 ◽  
Author(s):  
S. Vannitsem ◽  
F. Chomé
Keyword(s):  
Western Europe ◽  
State Of The Art ◽  
Regional Climate ◽  
Domain Size ◽  
Regional Model ◽  
Dynamical Behaviors ◽  
Climate Simulations ◽  
Intermediate Size ◽  
The Impact

Abstract The impact of domain size on regional climate simulations is explored in the context of a state-of-the-art regional model centered over western Europe. It is found that the quality of the climate simulations is highly dependent on the domain size. Moreover, the choice of an optimal version is more complex than usually thought, the less appropriate domain having an intermediate size (about 3000 km × 3000 km), and the best versions nearly cover a quarter of the Northern Hemisphere. The use of periodically reinitialized trajectories does improve the climate of suboptimal models but leads to unrealistic dynamical behaviors. The implications for regional climate simulations are briefly discussed.

Adaptation and Dependability and Their Key Role in Modern Software Engineering

2010 ◽  
Vol 1 (2) ◽  
pp. 1-14
Author(s):  
Vincenzo De Florio ◽  
Chris Blondia
Keyword(s):  
Software Engineering ◽  
Software Design ◽  
State Of The Art ◽  
Software Systems ◽  
Software Performance ◽  
Client Software ◽  
Effective System ◽  
The Face

Current software systems and the environments such systems are meant for requiring a precise characterization of the available resources and provisions to constantly re-optimize in the face of endogenous and exogenous changes and failures. This paper claims that it is simply not possible today to conceive software design without explicitly addressing adaptability and dependability. As an example, the authors remark on how mobile computing technologies call for effective software engineering techniques to design, develop and maintain services that are prepared to continue the distribution of a fixed, agreed-upon quality of service despite of the changes in the location of the client software, performance failures, and the characteristics of the environment. This paper concludes that novel paradigms are required for software engineering so as to provide effective system structures for adaptive and dependable services while keeping the design complexity under control. In this paper, the authors discuss this problem and propose one such structure, also briefly surveying the major milestones in the state of the art in this domain.

Online Social Exergames for Seniors

2020 ◽  
pp. 1599-1631
Author(s):  
Stathis Th. Konstantinidis ◽  
Ellen Brox ◽  
Per Egil Kummervold ◽  
Josef Hallberg ◽  
Gunn Evertsen ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Physical Activity ◽  
Physical Training ◽  
State Of The Art ◽  
Social Contact ◽  
High Quality ◽  
Current State ◽  
The Future ◽  
The Impact

The population is getting older, and the resources for care will be even more limited in the future than they are now. There is thus an aim for the society that the seniors can manage themselves as long as possible, while at the same time keeping a high quality of life. Physical activity is important to stay fit, and social contact is important for the quality of life. The aim of this chapter is to provide a state-of-the-art of online social exergames for seniors, providing glimpses of senior users' opinions and games limitations. The importance of the motivational techniques is emphasized, as well as the impact that the exergames have to seniors. It contributes to the book objectives focusing on current state and practice in health games for physical training and rehabilitation and the use of gamification, exploring future opportunities and uses of gamification in eHealth and discussing the respective challenges and limitations.

scholarly journals A Workload-Adaptive Streaming Partitioner for Distributed Graph Stores

2021 ◽  
Author(s):  
Ali Davoudian ◽  
Liu Chen ◽  
Hongwei Tu ◽  
Mengchi Liu
Keyword(s):  
Graph Partitioning ◽  
State Of The Art ◽  
Adaptive Streaming ◽  
Large Graphs ◽  
Load Imbalance ◽  
Graph Queries ◽  
The Impact ◽  
Query Patterns ◽  
Dynamic Query

AbstractStreaming graph partitioning methods have recently gained attention due to their ability to scale to very large graphs with limited resources. However, many such methods do not consider workload and graph characteristics. This may degrade the performance of queries by increasing inter-node communication and computational load imbalance. Moreover, existing workload-aware methods cannot consistently provide good performance as they do not consider dynamic workloads that keep emerging in graph applications. We address these issues by proposing a novel workload-adaptive streaming partitioner named WASP, that aims to achieve low-latency and high-throughput online graph queries. As each workload typically contains frequent query patterns, WASP exploits the existing workload to capture active vertices and edges which are frequently visited and traversed, respectively. This information is used to heuristically improve the quality of partitions either by avoiding the concentration of active vertices in a few partitions proportional to their visit frequencies or by reducing the probability of the cut of active edges proportional to their traversal frequencies. In order to assess the impact of WASP on a graph store and to show how easily the approach can be plugged on top of the system, we exploit it in a distributed graph-based RDF store. Our experiments over three synthetic and real-world graph datasets and the corresponding static and dynamic query workloads show that WASP achieves a better query performance against state-of-the-art graph partitioners, especially in dynamic query workloads.

scholarly journals Web-based lecture technologies and learning and teaching: a study of change in four Australian universities

2010 ◽  
Vol 26 (8) ◽  
Author(s):  
Maree Gosper ◽  
Margo McNeill ◽  
Rob Phillips ◽  
Greg Preston ◽  
Karen Woo ◽  
...  
Keyword(s):  
Learning Needs ◽  
Web Based ◽  
Learning And Teaching ◽  
Attendance Patterns ◽  
Key Concepts ◽  
Quality Of Learning ◽  
The Face ◽  
The Impact ◽  
Australian Universities

The uptake of web-based lecture technologies for recording and delivering live lectures has increased markedly in recent years. Students have responded positively, and for many their use has transformed learning – freeing them up from rigid timetables by providing choice in lecture attendance and supporting learning by extending the lecture experience and enabling them to revisit key concepts and ideas in their own time. Less transformational has been the impact on teaching. Although changing attendance patterns and disquiet about the quality of learning are of concern to many, lecturers have largely responded by simply modifying lectures. For most, the challenges of catering for the learning needs of a cohort with variable lecture attendance have not been addressed at a whole of the curriculum level. The technologies have been added on, rather than integrated into the curriculum. This paper will review the changes taking place in learning and teaching, explore the reluctance to embrace more wholesale change to the curriculum, and discuss the implications for institutions in the face of ongoing change.

scholarly journals RATIONALISATION RED FLAGS AND LIKELIHOOD OF FRAUD DETECTION IN NIGERIA

2020 ◽  
pp. 215-226
Author(s):  
Izevbigie, D.P.I. ◽  
Ibhadode, O.J.
Keyword(s):  
Fraud Detection ◽  
Financial Statements ◽  
Fraud Triangle ◽  
Red Flags ◽  
Probit Regression ◽  
Tax Rate ◽  
The Face ◽  
The Impact ◽  
Sas 99

The broad objective of this study is to ascertain the impact of rationalisation red flags as prescribed by SAS.99 in relation to the fraud triangle on the likelihood of fraud detection in Nigeria. The specific objectives of this study are to determine the effects of rationalisation red flags proxies: quality of earnings; and effective cash tax rate on the likelihood of fraud detection in Nigeria. This study used secondary data sourced from audited annual reports of quoted companies in the Nigeria Stock Exchange and a sample size of sixty-five (65) companies were used for a six-year period of 2009-2014. The variables were derived by making necessary computations using information reflected on the face of financial statements to derive our figures not explicitly stated on the face of the financial statements. The probit regression estimation analyses on the pooled data shows that Rationalization red flags such as quality of earnings and effective cash tax rate on the average cannot aid the likelihood of fraud detection in Nigeria. It is however recommended that forensic accountants should as a matter of necessity pay close attention to our findings in this study and make use of SAS.99 qualitative and quantitative proxies red flags when carrying fraud examination.

scholarly journals Service Quality of domestic airlines in the face of COVID-19 in Nepal

2021 ◽  
Vol 9 (02) ◽  
pp. 2061-2171
Author(s):  
Dr Gangaram Biswakarma ◽  
Achyut Gnawali
Keyword(s):  
Service Quality ◽  
Aviation Industry ◽  
Quantitative Methodology ◽  
Security Issues ◽  
The Face ◽  
Quality Dimensions ◽  
Domestic Airlines ◽  
Domestic Airline ◽  
The Impact

The coronavirus pandemic has turned the aviation industry on its head, transforming the passenger experience drastically. The airlines have faced significant challenges due to both the Covid-19 pandemic, the sequence of lockdowns and the provisions of safety and security legislation. There is more concern about the growing feeling that passengers are aware of the level of service. Airlines not only need to focus on service quality in today's highly competitive air transport environment, but also need to focus more on safety and security issues, especially at the time of the Covid-19 pandemic. The research related to these dimensional studies becomes more important in the COVID-19 scenario. Therefore, the objective of this study was to examine the impact of service quality dimensions on the overall quality of service of domestic airlines in Nepal in the midst of the Covid-19 pandemic. A quantitative methodology with a descriptive and explanatory research design was adopted in the study. A sample of 200 passengers recently travelling after the lockdown and reopening of the domestic airline service has been contacted. Out of which 160 responded to the questionnaire. In the sense of COVID-19 post lockdown operations, the service quality of domestic airlines is affected by various factors. All the likely factors that influence the quality of airlines need to be considered by airlines. Reliability, assurance, tangibility, empathy, and responsiveness are the variables. All these aspects play an important role in providing passengers with a reliable service. The dimensions of reliability, tangibility and responsiveness need to concentrate more on having the standard of service as desired in the sense of COVID-19 by domestic airlines in Nepal. It means that during COVID-19 and similar situations, tangibility must concentrate on the highest level of operation.  

Sign in / Sign up

Export Citation Format

Share Document