Analysis of Extrusion Welding Conditions for AlMg Alloys with High Mg Content

2016 ◽  
Vol 682 ◽  
pp. 401-407 ◽  
Author(s):  
Alicja Wojtyna ◽  
Dariusz Leśniak ◽  
Artur Rękas ◽  
Tomasz Latos ◽  
Krzysztof Zaborowski ◽  
...  
Keyword(s):  
Aluminium Alloys ◽  
Original Method ◽  
Die Design ◽  
High Quality ◽  
Weldability Tests ◽  
Welding Stress ◽  
Porthole Die ◽  
Extrusion Welding ◽  
Wide Range ◽  
Mg Content

In the work, an original method and a special modified device is presented enabling to determine welding conditions of hard deformable aluminium alloys. The main advantage of the proposed method is that it simulates conditions occurring in the welding chamber of the porthole dies. The weldability tests were performed for 5754 (3,5% Mg) and 5019 (5,5% Mg) alloys, in a wide range of temperatures and pressures. The microstructure and joints strength were examined. The welding conditions of AlMg alloys that allowed obtaining high-quality joints were determined. The obtained welding stress values will be the basis for extrusion porthole die design.

Weldability Investigations of AlCuMg Alloys for Extrusion Welding

2012 ◽  
Vol 57 (1) ◽  
pp. 7-17 ◽  
Author(s):  
D. Leśniak
Keyword(s):  
Aluminum Alloys ◽  
High Strength ◽  
Original Method ◽  
Die Design ◽  
Special Device ◽  
Welding Stress ◽  
Extrusion Welding ◽  
2024 Alloy ◽  
Wide Range ◽  
High Strength Aluminum Alloys

Weldability Investigations of AlCuMg Alloys for Extrusion Welding The extrusion of hollow shapes from high strength aluminum alloys with the use of porthole dies encounters, in practice, great difficulties, mainly due to the poor weldability of these materials and the high forces needed to conduct the process. In the work, an original method and a special device are presented, which enable to determine the welding conditions of hard deformable aluminum alloys. The main advantage of the proposed method is that it simulates the conditions occurring in the welding chamber of the porthole dies. The weldability tests were performed for the 2024 alloy with extreme contents of Cu and Mg, in a wide range of welding temperatures and pressures. The microstructure and the seam welds' strength were also examined. The welding conditions for 2024 alloy, which allowed for obtaining high-quality seam welds were determined. The parameter describing the ability to weld was defined as the stress necessary for the welding to the yield stress ratio (σw/k) and was determined for the analyzed alloys. The obtained welding stress values will be the basis for the porthole die design.

AMPCOLOY 570

Alloy Digest ◽  
1980 ◽  
Vol 29 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Iron Alloy ◽  
Heat Treating ◽  
Nickel Aluminum ◽  
High Quality ◽  
Glass Making ◽  
Temperature Performance ◽  
Wide Range ◽  
Cobalt Iron

Abstract AMPCOLOY 570 is a cast copper-nickel-aluminum-cobalt-iron alloy specially developed for applications involving severe stresses and high temperatures, such as glass-making molds and plate-glass rolls. It is significantly superior to cast iron which has been commonly used for glass-making molds. Good foundry techniques will yield high-quality castings of Ampcoloy 570 in a wide range of section sizes. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-392. Producer or source: Ampco Metal Inc..

Guiding Principals: Middle-Manager Coaching and Human-Capital Reform

2020 ◽  
Vol 122 (10) ◽  
pp. 1-50
Author(s):  
Susan Bush-Mecenas ◽  
Julie A. Marsh ◽  
Katharine O. Strunk
Keyword(s):  
Professional Development ◽  
Human Capital ◽  
Policy Implementation ◽  
Survey Data ◽  
Empirical Work ◽  
Think Aloud ◽  
High Quality ◽  
Wide Range ◽  
Role Of Principal

Background/Context School leaders are central to state and district human-capital reforms (HCRs), yet they are rarely equipped with the skills to implement new evaluation, professional development, and personnel data systems. Although districts increasingly offer principals coaching and training, there has been limited empirical work on how these supports influence principals’ HCR-related practices. Purpose Drawing on a two-year, mixed-methods study in the Los Angeles Unified School District (LAUSD), this article examines the role of principal supervisors in HCRs. We ask: What role did principal supervisors (Instructional Directors [IDs]) play in the implementation of human-capital reforms? What did high-quality coaching on the part of IDs look like in this context? Research Design Our two-part analysis draws upon survey and interview data. First, we conducted descriptive analyses and significance testing using principal and ID survey data to examine the correlations among principals’ ratings of ID coaching quality, ID coaching practices, and principals’ implementation of HCRs. Second, we conducted in-depth interviews, using a think-aloud protocol, with two sets of IDs—those consistently highly-rated and those with mixed ratings—who were identified using principals’ reports of coaching quality. Following interview coding, we created various case-ordered metamatrix displays to analyze our qualitative data in order to identify patterns in coaching strategy and approach across IDs, content, and contexts. Findings First, our survey data indicate that receiving high-quality coaching from IDs is correlated with stronger principal support for and implementation of HCRs. Our survey findings further illustrate that IDs support a wide range of principals’ HCR activities. Second, our think-aloud interviews with case IDs demonstrate that coaching strategy and approach vary between consistently highly-rated and mixed-rated coaches: Consistently highly-rated IDs emphasize the importance of engaging in, or defining HCR problems as, joint work alongside principals, while mixed-rated IDs often emphasize the use of tools to guide principal improvement. We find that, on the whole, the consistently highly-rated IDs in our sample employ a nondirective approach to coaching more often than mixed-rated coaches. Conclusions These findings contribute to a growing literature on the crucial role of principal supervisors as coaches to improve principals’ instructional leadership and policy implementation. While exploratory, this study offers the first steps toward building greater evidence of the connections between high-quality coaching and policy implementation, and it may have implications for the design and implementation of professional development for principal supervisors and the selection and placement of supervisors with principals.

An open-source R-package and web application for high-quality probabilistic predictions in hydrology

2021 ◽  
Author(s):  
Jason Hunter ◽  
Mark Thyer ◽  
Dmitri Kavetski ◽  
David McInerney
Keyword(s):  
Open Source ◽  
Web Application ◽  
R Package ◽  
Error Model ◽  
Objective Functions ◽  
High Quality ◽  
Wide Range ◽  
Probabilistic Error

<p>Probabilistic predictions provide crucial information regarding the uncertainty of hydrological predictions, which are a key input for risk-based decision-making. However, they are often excluded from hydrological modelling applications because suitable probabilistic error models can be both challenging to construct and interpret, and the quality of results are often reliant on the objective function used to calibrate the hydrological model.</p><p>We present an open-source R-package and an online web application that achieves the following two aims. Firstly, these resources are easy-to-use and accessible, so that users need not have specialised knowledge in probabilistic modelling to apply them. Secondly, the probabilistic error model that we describe provides high-quality probabilistic predictions for a wide range of commonly-used hydrological objective functions, which it is only able to do by including a new innovation that resolves a long-standing issue relating to model assumptions that previously prevented this broad application.  </p><p>We demonstrate our methods by comparing our new probabilistic error model with an existing reference error model in an empirical case study that uses 54 perennial Australian catchments, the hydrological model GR4J, 8 common objective functions and 4 performance metrics (reliability, precision, volumetric bias and errors in the flow duration curve). The existing reference error model introduces additional flow dependencies into the residual error structure when it is used with most of the study objective functions, which in turn leads to poor-quality probabilistic predictions. In contrast, the new probabilistic error model achieves high-quality probabilistic predictions for all objective functions used in this case study.</p><p>The new probabilistic error model and the open-source software and web application aims to facilitate the adoption of probabilistic predictions in the hydrological modelling community, and to improve the quality of predictions and decisions that are made using those predictions. In particular, our methods can be used to achieve high-quality probabilistic predictions from hydrological models that are calibrated with a wide range of common objective functions.</p>

scholarly journals Seed conditioning of red oak: a recalcitrant North American seed

1998 ◽  
Vol 55 (spe) ◽  
pp. 67-73 ◽  
Author(s):  
D.K. Struve
Keyword(s):  
North American ◽  
Seed Quality ◽  
Quercus Rubra ◽  
Production Systems ◽  
Red Oak ◽  
High Quality ◽  
Stand Establishment ◽  
Conditioning Treatment ◽  
Wide Range ◽  
Seed Conditioning

A ten day aerated water soak was developed as a seed conditioning treatment for red oak (Quercus rubra L.). Conditioned seeds had higher germination completeness, uniformity and speed compared to control seeds. Seeds could be conditioned under a wide range of temperatures and durations. Conditioned seeds were maintained at 7(0)C for 30 days without loss of seed quality. During conditioning, pericarps split in response to seed hydration. Split pericarps could be used as a pre-sowing indicator for high quality seeds. Seed conditioning was ineffective on dormant seeds. Increased crop uniformity and higher stand establishment can be realized by subjecting red oak acorns to an aerated water soak treatment followed by selecting seeds with split pericarps. These results are especially important in container production systems where limited numbers of value seeds are available.

Dependence of Scintillators Optical Properties on Intrinsic Structural Defects

1994 ◽  
Vol 348 ◽  
Author(s):  
N.V. Kilassen
Keyword(s):  
Plastic Deformation ◽  
Optical Properties ◽  
Crystal Growth ◽  
Spectral Distribution ◽  
Light Output ◽  
Structural Defects ◽  
High Quality ◽  
Intrinsic Defects ◽  
Distribution Kinetics ◽  
Wide Range

ABSTRACTThe studies of the dependence of the optical properties of various scintillators on intrinsic structural defects have been reviewed. The greater part of the review is devoted to the defects introduced by plastic deformation. A wide range of variations in the light output, spectral distribution, kinetics and other properties has been observed. These defects can be induced during crystal growth, annealing, processing, etc. The proper regulation of the superstructure of intrinsic defects can ensure the production of high quality scintillators having required properties.

scholarly journals The SeaSWIR dataset

2018 ◽  
Author(s):  
Els Knaeps ◽  
David Doxaran ◽  
Ana Dogliotti ◽  
Bouchra Nechad ◽  
Kevin Ruddick ◽  
...  
Keyword(s):  
Quality Control ◽  
Suspended Matter ◽  
Short Wave ◽  
Total Suspended Matter ◽  
High Quality ◽  
Detailed Measurement ◽  
La Plata ◽  
Measurement Protocol ◽  
Wide Range ◽  
Quality Measurements

Abstract. The SeaSWIR dataset consists of 137 ASD (Analytical Spectral Devices, Inc.) marine reflectances, 137 Total Suspended Matter (TSM) measurements and 97 turbidity measurements gathered at three turbid estuarine sites (Gironde, La Plata, Scheldt). The dataset is valuable because of the high quality measurements of the marine reflectance in the Short Wave InfraRed I region (SWIR-I: 1000–1200 nm) and SWIR-II (1200–1300 nm) and because of the wide range of TSM concentrations from 48 mg L−1 up to 1400 mg L−1. The ASD measurements were gathered using a detailed measurement protocol and were subjected to a strict quality control. The SeaSWIR marine reflectance is characterized by low reflectance at short wavelengths (

scholarly journals An Adaptive Bitrate Switching Algorithm for Speech Applications in Context of WebRTC

2021 ◽  
Vol 17 (4) ◽  
pp. 1-21
Author(s):  
Mohannad Alahmadi ◽  
Peter Pocta ◽  
Hugh Melvin
Keyword(s):  
Real Time ◽  
Data Exchange ◽  
Quality Of Experience ◽  
End User ◽  
High Quality ◽  
Content Type ◽  
Switching Algorithm ◽  
Wide Range ◽  
The Impact

Web Real-Time Communication (WebRTC) combines a set of standards and technologies to enable high-quality audio, video, and auxiliary data exchange in web browsers and mobile applications. It enables peer-to-peer multimedia sessions over IP networks without the need for additional plugins. The Opus codec, which is deployed as the default audio codec for speech and music streaming in WebRTC, supports a wide range of bitrates. This range of bitrates covers narrowband, wideband, and super-wideband up to fullband bandwidths. Users of IP-based telephony always demand high-quality audio. In addition to users’ expectation, their emotional state, content type, and many other psychological factors; network quality of service; and distortions introduced at the end terminals could determine their quality of experience. To measure the quality experienced by the end user for voice transmission service, the E-model standardized in the ITU-T Rec. G.107 (a narrowband version), ITU-T Rec. G.107.1 (a wideband version), and the most recent ITU-T Rec. G.107.2 extension for the super-wideband E-model can be used. In this work, we present a quality of experience model built on the E-model to measure the impact of coding and packet loss to assess the quality perceived by the end user in WebRTC speech applications. Based on the computed Mean Opinion Score, a real-time adaptive codec parameter switching mechanism is used to switch to the most optimum codec bitrate under the present network conditions. We present the evaluation results to show the effectiveness of the proposed approach when compared with the default codec configuration in WebRTC.

scholarly journals A Review on Additive Manufacturing of Micromixing Devices

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Marina Garcia-Cardosa ◽  
Francisco-Javier Granados-Ortiz ◽  
Joaquín Ortega-Casanova
Keyword(s):  
Life Cycle ◽  
Additive Manufacturing ◽  
High Performance ◽  
Future Prospects ◽  
High Quality ◽  
Printing Technology ◽  
Wide Range ◽  
The Moment ◽  
Manufacturing Technologies

In recent years, additive manufacturing has gained importance in a wide range of research applications such as medicine, biotechnology, engineering, etc. It has become one of the most innovative and high-performance manufacturing technologies of the moment. This review aims to show and discuss the characteristics of different existing additive manufacturing technologies for the construction of micromixers, which are devices used to mix two or more fluids at microscale. The present manuscript discusses all the choices to be made throughout the printing life cycle of a micromixer in order to achieve a high-quality microdevice. Resolution, precision, materials, and price, amongst other relevant characteristics, are discussed and reviewed in detail for each printing technology. Key information, suggestions, and future prospects are provided for manufacturing of micromixing machines based on the results from this review.

scholarly journals Ensuring Seedling Quality through Fruit Tree Nursery Accreditation and Implications for Forest Nursery Accreditation

2010 ◽  
pp. 81-88
Author(s):  
Don Immanuel Edralin ◽  
Agustin Mercado
Keyword(s):  
The Philippines ◽  
Fruit Tree ◽  
Tree Planting ◽  
Tree Seedlings ◽  
Department Of Agriculture ◽  
High Quality ◽  
Tree Nursery ◽  
Wide Range ◽  
The Government ◽  
Planting Materials

he fruit tree nursery accreditation scheme implemented by the Philippine Department of Agriculture has been promoted to enhance the supply of high quality fruit tree planting materials and reduce the number of dubious seedling market players. This paper examines the advantages to participating nurseries in the fruit tree nursery accreditation scheme and draws implications for possible formulation of a scheme to accredit forest tree nurseries in the Philippines. Data were collected from interviews with accredited fruit tree nursery operators and the nursery accreditation officer-in-charge in Northern Mindanao province. A major advantage of nursery accreditation is that only accredited fruit tree nursery operators can participate in the bidding process of the government seedling procurement program, which always involves a substantial volume of seedlings. As a form of advertisement, accredited nurseries are posted on the government website thus creating a wide range of market opportunities which results in increased sales. Other advantages enjoyed by accredited fruit tree nurseries include receiving free training in improving seedling production and occasionally receiving high quality propagation materials (scions and seedlings), subsidies for pesticides and fertilizers and free soil tests. Observations of advantages gained by nursery operators adopting certification have encouraged other nursery operators to apply for accreditation. Accreditation by the Department of Agriculture places emphasis on maintaining high genetic quality as well as high physical quality of planting materials. Accrediting forestry nurseries is seen as a potential policy option that can expand the supply of high quality tree seedlings in the Philippines, as has been the experience with fruit tree nursery certification.

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