Identification of cord sources in glass using CFD

2020 ◽  
Vol 61 (5) ◽  
pp. 141-147
Author(s):  
P. Vrábel ◽  
◽  
P. Šimurka ◽  
M. Maryška ◽  
P. Vl ◽  
...  
Keyword(s):  
Production Line ◽  
Direct Methods ◽  
Process Data ◽  
Cfd Simulations ◽  
Glass Quality ◽  
Computational Flow Dynamics ◽  
Chemical Character ◽  
Set Up ◽  
Dynamics Calculation ◽  
Positive Effect

Cord appearance in the glass industry is a serious problem in high glass quality tableware production. The increased frequency of sharp cords provoked a serious analysis on cord origin and their elimination at the production line. Optical microscopy and electron microprobe analysis (EMA) were applied as direct methods for cord identification. A computational flow dynamics calculation (CFD) and process data analysis were used to verify the hypothesised source of the inhomogeneity. The hypothesis on origin of ZrO2 free cords containing high amounts of Al2O3 was postulated in relation to the refractory material composition of the forehearth. Calculations showed that the suggested mechanism at temperatures between 1200 and 1300°C was relevant. The hypothesis was supported by a change of chemical character of the cords after partial removal of the poorly resistant material. Also the average cord frequency was reduced on a production line from 53 to 17%. CFD simulations indicated that there may exist an effective mixing strategy on cord dissolution. Increasing stirrer rotation speed in a tempering part of the forehearth had a positive effect on cord disruption. The proposed stirrer set up decreased the cord frequency to less than 2%.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

An Approach for Efficient CFD Simulations of an Ejector Air Injection System for Active Aerodynamic Compressor Stabilization

2017 ◽  
Author(s):  
Sebastian Brehm ◽  
Felix Kern ◽  
Jonas Raub ◽  
Reinhard Niehuis
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Air Injection ◽  
Injection System ◽  
Cfd Simulations ◽  
Data Set ◽  
Numerical Effort ◽  
Enhance Efficiency ◽  
Set Up ◽  
Novel Concept

The Institute of Jet Propulsion at the University of the German Federal Armed Forces Munich has developed and patented a novel concept of air injection systems for active aerodynamic stabilization of turbo compressors. This so-called Ejector Injection System (EIS) utilizes the ejector effect to enhance efficiency and impact of the aerodynamic stabilization of the Larzac 04 two-spool turbofan engine’s LPC. The EIS design manufactured recently has been subject to CFD and experimental pre-investigations in which the expected ejector effect performance has been proven and the CFD set-up has been validated. Subsequently, optimization of the EIS ejector geometry comes into focus in order to enhance its performance. In this context, CFD parameter studies on the influence of in total 16 geometric and several aerodynamic parameters on the ejector effect are required. However, the existing and validated CFD set-up of the EIS comprises not only the mainly axisymmetric ejector geometry but also the highly complex 3D supply components upstream of the ejector geometry. This is hindering large scale CFD parameter studies due to the numerical effort required for these full 3D CFD simulations. Therefore, an approach to exploit the overall axissymmetry of the ejector geometry is presented within this paper which reduces the numerical effort required for CFD simulations of the EIS by more than 90%. This approach is verified by means of both experimental results as well as CFD predictions of the full 3D set-up. The comprehensive verification data set contains wall pressure distributions and the mass flow rates involved at various Aerodynamic Operating Points (AOP). Furthermore, limitations of the approach are revealed concerning its suitability e.g. to judge the response of the attached compressor of future EIS designs concerning aerodynamic stability or cyclic loading.

scholarly journals X̅ and R control charts based on marshall-olkin inverse log-logistic distribution for positive skewed data

2020 ◽  
Vol 1 (1) ◽  
pp. 9-16
Author(s):  
O. L. Aako ◽  
J. A. Adewara ◽  
K. S Adekeye ◽  
E. B. Nkemnole
Keyword(s):  
Control Chart ◽  
Control Charts ◽  
Average Run Length ◽  
Logistic Distribution ◽  
Skewed Data ◽  
Process Data ◽  
And Performance ◽  
Set Up ◽  
Control Limits ◽  
Normally Distributed

The fundamental assumption of variable control charts is that the data are normally distributed and spread randomly about the mean. Process data are not always normally distributed, hence there is need to set up appropriate control charts that gives accurate control limits to monitor processes that are skewed. In this study Shewhart-type control charts for monitoring positively skewed data that are assumed to be from Marshall-Olkin Inverse Loglogistic Distribution (MOILLD) was developed. Average Run Length (ARL) and Control Limits Interval (CLI) were adopted to assess the stability and performance of the MOILLD control chart. The results obtained were compared with Classical Shewhart (CS) and Skewness Correction (SC) control charts using the ARL and CLI. It was discovered that the control charts based on MOILLD performed better and are more stable compare to CS and SC control charts. It is therefore recommended that for positively skewed data, a Marshall-Olkin Inverse Loglogistic Distribution based control chart will be more appropriate.

scholarly journals Forced Cohabitation during Coronavirus Lockdown in Italy: A Study on Coping, Stress and Emotions among Different Family Patterns

2020 ◽  
Vol 9 (12) ◽  
pp. 3906
Author(s):  
Emanuela Mari ◽  
Angelo Fraschetti ◽  
Giulia Lausi ◽  
Alessandra Pizzo ◽  
Michela Baldi ◽  
...  
Keyword(s):  
Coping Strategies ◽  
Physical Space ◽  
Total Sample ◽  
Italian Population ◽  
Online Questionnaire ◽  
Family Patterns ◽  
Stress Coping Strategies ◽  
Set Up ◽  
As Stress ◽  
Positive Effect

Background: At the beginning of 2020, a pandemic caused by a new strain of coronavirus occurred. On March 9th, the Italian population was forced to lockdown to prevent the spread of this new virus. This event forced families and cohabitants to spend their entire days and weeks in the same physical space, interacting with partners and children with a very different degree of intimacy than in the earlier situation. The present study investigated the effects of being forced to live together on different family patterns, on various dimensions such as stress, coping strategies, time perception and quality evaluation of cohabitation. Method: A total sample consisting of 1750 individuals was recruited through a random sample of probability across the Italian country. Due to the lockdown condition, an online questionnaire was set up; several validated scales were chosen, and some open-ended items were included for the thoughts of the participants. Results: The results showed statistically significant differences between the three family patterns examined. Conclusion: During the forced period of living together, a positive effect could be inferred as given by the presence of children and the collaborative coping strategies that have been adopted; the results have been discussed according to the literature on the topic.

scholarly journals Interactions between organisms and parent materials of a constructed Technosol shape its hydrostructural properties

SOIL ◽  
2016 ◽  
Vol 2 (2) ◽  
pp. 163-174 ◽  
Author(s):  
Maha Deeb ◽  
Michel Grimaldi ◽  
Thomas Z. Lerch ◽  
Anne Pando ◽  
Agnès Gigon ◽  
...  
Keyword(s):  
Parent Material ◽  
Material Composition ◽  
Positive Role ◽  
Parent Materials ◽  
Positive Effects ◽  
Available Water ◽  
Set Up ◽  
Full Factorial ◽  
Positive Effect ◽  
Better Than

Abstract. There is no information on how organisms influence hydrostructural properties of constructed Technosols and how such influence will be affected by the parent-material composition factor. In a laboratory experiment, parent materials, which were excavated deep horizons of soils and green waste compost (GWC), were mixed at six levels of GWC (from 0 to 50 %). Each mixture was set up in the presence/absence of plants and/or earthworms, in a full factorial design (n  =  96). After 21 weeks, hydrostructural properties of constructed Technosols were characterized by soil shrinkage curves. Organisms explained the variance of hydrostructural characteristics (19 %) a little better than parent-material composition (14 %). The interaction between the effects of organisms and parent-material composition explained the variance far better (39 %) than each single factor. To summarize, compost and plants played a positive role in increasing available water in macropores and micropores; plants were extending the positive effect of compost up to 40 and 50 % GWC. Earthworms affected the void ratio for mixtures from 0 to 30 % GWC and available water in micropores, but not in macropores. Earthworms also acted synergistically with plants by increasing their root biomass, resulting in positive effects on available water in macropores. Organisms and their interaction with parent materials positively affected the hydrostructural properties of constructed Technosols, with potential positive consequences on resistance to drought or compaction. Considering organisms when creating Technosols could be a promising approach to improve their fertility.

Sensitivity Analysis of Semi-Circular Bending Test using Plackett–Burman Matrix

2020 ◽  
Vol 2674 (2) ◽  
pp. 302-312
Author(s):  
Shadi Saadeh ◽  
Yazan Al-Zubi ◽  
Enad Mahmoud ◽  
David Renteria ◽  
Louay Mohammad
Keyword(s):  
Test Method ◽  
Bending Test ◽  
Test Results ◽  
Notch Depth ◽  
Air Voids ◽  
Scb Test ◽  
Negative Effect ◽  
American Society ◽  
Set Up ◽  
Positive Effect

The semi-circular bending (SCB) test is a recently developed test method, adopted by the American Society of Testing and Material (ASTM) as ASTM D8044, to evaluate the cracking resistance of asphalt mixtures. To measure the robustness of the SCB test, a ruggedness test is needed. In this study, the effect of small changes in the key parameters of the test method on the results of the test were numerically investigated. The test method has many variables and set up conditions. Examining all of these parameters would be cumbersome using traditional testing and statistical techniques, as they require a significantly high number of samples. The Plackett–Burman (PB) technique was used to conduct the ruggedness test while reducing the number of tests required. Seven parameters have been examined: notch location, notch depth (low, intermediate and high), air voids, loading rate, and span length. Even using the PB technique, 16 scenarios need to be tested, and each scenario requires three specimens, one for each of the three notch depths. Hence the process requires plenty of time and material. In this study, the SCB test was modeled using a discrete element method (DEM) approach to analyze the fracture behavior of the samples. DEM was used to develop a model that reduced the time and materials required for the SCB test. Results showed that the parameters with most positive effect were intermediate notch depth and notch location, while those with the most negative effect were loading rates and air voids.

Challenges of Data Acquisition and Analysis for Characteristics-Driven and Metrology-Based Optimization of Milling Process Development

2014 ◽  
Vol 704 ◽  
pp. 233-238
Author(s):  
Laura Niendorf ◽  
Markus Grosse Boeckmann ◽  
Robert Schmitt
Keyword(s):  
Data Mining ◽  
Process Development ◽  
Early Stage ◽  
Milling Process ◽  
Production Environment ◽  
Process Data ◽  
Related Data ◽  
Research Activities ◽  
Future Production ◽  
Set Up

The research and practical use of data and data-mining in production environment is still at an early stage. Although almost every manufacturing company collects a lot of process and product related data they often do neither use nor deploy this data in order to optimize or even analyze their production processes. The acquisition of process data brings several advantages. On the one hand the implicit knowledge is permanently stored and on the other hand it is possible to learn from previous process failures. The acquired knowledge could then be applied to all future production tasks. Although many research activities can be observed since the late 90s, none of them managed the transfer to practical usage. In order to encourage the practical transfer of data-mining in production environment this paper presents a metrology-based test set-up and therewith arising challenges when consistently acquiring and processing inhomogeneous process, product and machine data. For the experimental set-up, on-machine metrology systems were developed and integrated into a 5-axis milling machine to gain much significant data.

scholarly journals Increase of Productivity and Neutralization of Pathological Processes in Plants of Grain and Fruit Crops with the Help of Aqueous Solutions Activated by Plasma of High-Frequency Glow Discharge

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2161
Author(s):  
Yuri K. Danilejko ◽  
Sergey V. Belov ◽  
Alexey B. Egorov ◽  
Vladimir I. Lukanin ◽  
Vladimir A. Sidorov ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Aqueous Solutions ◽  
Chemical Reactor ◽  
Fruit Crops ◽  
Plasma Chemical Reactor ◽  
Set Up ◽  
Reactor Operating ◽  
Short Time ◽  
First Time ◽  
Positive Effect

In this work, we, for the first time, manufactured a plasma-chemical reactor operating at a frequency of 0.11 MHz. The reactor allows for the activation of large volumes of liquids in a short time. The physicochemical properties of activated liquids (concentration of hydrogen peroxide, nitrate anions, redox potential, electrical conductivity, pH, concentration of dissolved gases) are characterized in detail. Antifungal activity of aqueous solutions activated by a glow discharge has been investigated. It was shown that aqueous solutions activated by a glow discharge significantly reduce the degree of presence of phytopathogens and their effect on the germination of such seeds. Seeds of cereals (sorghum and barley) and fruit (strawberries) crops were studied. The greatest positive effect was found in the treatment of sorghum seeds. Moreover, laboratory tests have shown a significant increase in sorghum drought tolerance. The effectiveness of the use of glow-discharge-activated aqueous solutions was shown during a field experiment, which was set up in the saline semi-desert of the Northern Caspian region. Thus, the technology developed by us makes it possible to carry out the activation of aqueous solutions on an industrial scale. Water activated by a glow discharge exhibits antifungicidal activity and significantly accelerates the development of the grain and fruit crops we studied. In the case of sorghum culture, glow-discharge-activated water significantly increases drought resistance.

scholarly journals Towards automation of operando experiments: A case study in contactless conductivity measurements

2021 ◽  
Author(s):  
Peter Kraus ◽  
Elisabeth Wolf ◽  
Charlotte Prinz ◽  
Giulia Bellini ◽  
Annette Trunschke ◽  
...  
Keyword(s):  
Best Practice ◽  
Conductivity Measurement ◽  
Lessons Learned ◽  
Main Body ◽  
Process Data ◽  
Post Process ◽  
Set Up ◽  
Machine Readable ◽  
Machine Readable Form

Automation of experiments is a key component on the path of digitalisation in catalysis and related sciences. Here we present the lessons learned and caveats avoided during the automation of our contactless conductivity measurement set-up, capable of operando measurement of catalytic samples. We briefly discuss the motivation behind the work, the technical groundwork required, and the philosophy guiding our design. The main body of this work is dedicated to the detailing of the implementation of the automation, data structures, as well as the modular data processing pipeline. The open-source toolset developed as part of this work allows us to carry out unattended and reproducible experiments, as well as post-process data according to current best practice. This process is illustrated by implementing two routine sample protocols, one of which was included in the Handbook of Catalysis, providing several case studies showing the benefits of such automation, including increased throughput and higher data quality. The datasets included as part of this work contain catalytic and operando conductivity data, and are self-consistent, annotated with metadata, and are available on a public repository in a machine-readable form. We hope the datasets as well as the tools and workflows developed as part of this work will be an useful guide on the path towards automation and digital catalysis.

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