The effect of dispersants on the properties of low-cement concrete for the furnace of smelting of jewelry waste

2021 ◽  
pp. 49-52
Author(s):  
B. L. Krasnyi ◽  
K. I. Ikonnikov ◽  
A. L. Galganova
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Cement Concrete ◽  
Concrete Mass ◽  
Refractory Crucible ◽  
Ceramic Crucible ◽  
The Impact

Melting in ceramic crucible is one of the stages of recycling jewelry production. Conceptivity of concrete mass plays an important role in molding a large-scale refractory crucible to vibration. The impact of a number of commercially available dispersants (CASTAment FS 10, MELFLUX 1641 F, peramin al 200, FF7 SPEZIAL and PC-1701) on the rheology of the low-cement concrete mass of corundo-mullite-zirconium composition and the physico-mechanical properties of the material are considered. The best results were obtained using the PC-1701 dispersant. 

Characteristics and Mechanical Properties of Rolling-Element Bearings

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Lv Haiting
Keyword(s):  
Mechanical Properties ◽  
Load Distribution ◽  
Large Scale ◽  
Roller Bearing ◽  
Rolling Bearing ◽  
Fe Model ◽  
Rolling Bearings ◽  
Angle Variation ◽  
Supporting Structure ◽  
The Impact

Large rolling bearings are mainly used in occasions of low speed and heavy load due to its desirable properties such as large-scale structure and high bearing capacity. Currently, the research emphases of large rolling bearings are focussed on the load distribution, load carrying capacity, fatigue life and structure optimization. Bearings used in heavy vehicles belong to large bearings, whose reliability is also very important. In this paper, the characteristics of the structures of four point angular contact ball bearings and three row cylindrical roller bearing are analyzed. Finite element (FE) model is used to simulate the load distribution and angle variation in the actual working process of a large rolling bearing. In order to analyze the impact of the constraints, the stiffness and the local hard point of the supporting structure on the mechanical properties of large rolling bearings, a series of simplified FE models of large rolling bearing with different constraints and supporting structure has been carried out.

scholarly journals A Thermo-Mechanical Analysis of Laser Hot Wire Additive Manufacturing of NAB

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1023
Author(s):  
Glenn W. Hatala ◽  
Qian Wang ◽  
Edward W. Reutzel ◽  
Charles R. Fisher ◽  
Jennifer K. Semple
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Large Scale ◽  
Mechanical Analysis ◽  
Simulation Software ◽  
Aluminum Bronze ◽  
Hot Wire ◽  
Temperature Dependent ◽  
Temperature Dependent Properties ◽  
The Impact

There is increased interest in using nickel aluminum bronze (NAB) alloys in large-scale directed energy deposition additive manufacturing (DEDAM) processes for maritime applications, but one challenge lies in the component distortion that results from residual stress generated during fabrication. This paper describes the development and evaluation of thermo-mechanical simulations for laser hot wire (LHW) DEDAM of NAB to predict part distortion. To account for the dearth of temperature-dependent properties for NAB C95800 in open literature and public databases, temperature-dependent material and mechanical properties for NAB C95800 were experimentally measured using test specimens fabricated with a variety of DEDAM processes. Autodesk’s Netfabb Local Simulation software, a commercial finite-element based AM solver, was employed but with its heat source model modified to accommodate LHW DEDAM’s oscillating laser path and additional energy input supplied by the preheated wire feedstock. Thermo-mechanical simulations were conducted using both the acquired temperature-dependent material and mechanical properties and the constant room-temperature properties to assess the impact on simulation accuracy. The usage of constant properties in the thermo-mechanical analysis resulted in significantly different predicted distortion compared to those using the temperature-dependent properties, at times even predicting substrate displacement in an opposite direction.

Low Temperature Mechanical Properties of Power Transmission Tower Steel

2017 ◽  
Vol 898 ◽  
pp. 772-777
Author(s):  
Jia Xing Wang ◽  
Xu Ming Wang ◽  
Hui Guo ◽  
Ai Min Zhao ◽  
Liu Wei
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Toughness ◽  
Large Scale ◽  
Rolling Direction ◽  
Vertical Direction ◽  
Total Elongation ◽  
Transmission Tower ◽  
Weld Region ◽  
The Impact

The tensile and impact tests were used to study the mechanical properties under different temperatures of 300 mm large-scale angle steel at different positions, especially the tensile strength, yield strength, total elongation and impact toughness in the range of-40 oC to 20 oC. The results showed that different regions had great differences in the microstructures and impact toughness, in which the size of edge region was the smallest and the impact toughness was the best. However, the coarsened grain of heat affected zone at weld region had deteriorated to the low temperature impact toughness. When the impact energy was 34 J, the ductile-brittle transition temperature of weld, center, vertex and edge were-7.2 oC, -33.0 oC, -31.5 oC and far less than-40 oC, respectively. Meanwhile, because the banded structure was detrimental to the ductility, the elongation of rolling direction was lower than vertical direction. The strength of weld region was higher than other locations, but the elongation was obviously decreased.

scholarly journals The Weld Microstructure and Mechanical Properties of the Alloy 52 and Its Variants with Applied Electromagnetic Stirring during Welding

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 351
Author(s):  
Tai-Jung Wu ◽  
Sheng-Long Jeng ◽  
Junn-Yuan Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Large Scale ◽  
Base Alloy ◽  
Welding Process ◽  
Electromagnetic Stirring ◽  
Weld Microstructure ◽  
Microstructure And Mechanical Properties ◽  
Dominant Feature ◽  
The Impact

This study investigated the impact of electromagnetic stirring (EMS) on nickel-base alloy welds prepared with the gas tungsten arc welding process. Alloy 52 and its variants, Alloy 52M and Alloy 52MSS, were carefully evaluated with their weld microstructure and mechanical properties. The results showed that the welds exhibited a typical microstructure of dendrites, and that the dendrites could be refined by electromagnetic stirring. Meanwhile, with an application of EMS, the precipitates became smaller and more evenly distributed in the inter-dendritic areas. Ti(N,C)s, Nb/(Nb,Si)Cs, and large-scale Laves phase with (Nb,Mo,Ti)Cs were the precipitates present in the Alloy 52, Alloy 52M, and Alloy 52MSS welds, respectively. With the refined microstructure, both Alloy 52 and Alloy 52M welds were observed to have an increase in their tensile strength, with a decrease in their elongations. Comparatively, for the Alloy 52MSS weld, the tensile strength was enhanced along with a slight increase in elongation. Deep and dense dimples were a dominant feature of low-Nb-additions welds, and dendrite-like features were found prevalent among the Alloy 52MSS welds. With EMS, the dimples of Alloy 52 welds and the dendrite-like features of Alloy 52MSS welds became finer, while the dimples of Alloy 52M welds grew coarser.

The Mechanical Property Comparison of Two Kinds of Counterweight Booms of Stacker Reclaimer

2013 ◽  
Vol 690-693 ◽  
pp. 1966-1971
Author(s):  
Peng Shang ◽  
Kai Cheng Qi ◽  
Ya Xu Wang ◽  
Yu Ming Guan
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Large Scale ◽  
The Finite Element Method ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Different Types ◽  
The Impact

This paper used the finite element method to compare the mechanical properties of two different configuration counterweight booms of the bucket wheel stacker reclaimer. And two different forms of the finite element analysis model of the counterweight booms were built in ANSYS. The stresses and strains under its working state were calculated. Then the impact of the counterweight arm to the force and stability of the whole rack could be analyzed. The results of this analysis provided a basis to select different types of the counterweight booms in different environment, and it has an important guidance and reference significance to the design and analysis of counterweight booms of large-scale machinery.

scholarly journals Mechanical variations in proteins with large-scale motions highlight the formation of structural locks

2017 ◽  
Author(s):  
Sophie Sacquin-Mora
Keyword(s):  
Mechanical Properties ◽  
Protein Function ◽  
Large Scale ◽  
Structural Changes ◽  
Coarse Grain ◽  
Local Rigidity ◽  
New Class ◽  
Closed Conformation ◽  
Closed Structure ◽  
The Impact

AbstractProtein function depends just as much on flexibility as on structure, and in numerous cases, a protein’s biological activity involves transitions that will impact both its conformation and its mechanical properties. Here, we use a coarse-grain approach to investigate the impact of structural changes on protein flexibility. More particularly, we focus our study on proteins presenting large-scale motions. We show how calculating directional force constants within residue pairs, and investigating their variation upon protein closure, can lead to the detection of a limited set of residues that form a structural lock in the protein’s closed conformation. This lock, which is composed of residues whose side-chains are tightly interacting, highlights a new class of residues that are important for protein function by stabilizing the closed structure, and that cannot be detected using earlier tools like local rigidity profiles or distance variations maps, or alternative bioinformatics approaches, such as coevolution scores.

Alloy Design and Microstructure Control for the Production of Heavy Ductile Irons Used in Large-Scale Windmills

2013 ◽  
Vol 652-654 ◽  
pp. 909-915
Author(s):  
Yung Ning Pan ◽  
Chi Chia Lin ◽  
Re Mo Chang
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Alloy Design ◽  
Chemical Compositions ◽  
Regression Equations ◽  
Cast Irons ◽  
Pearlite Content ◽  
Temperature Impact ◽  
Si Content ◽  
The Impact

The primary purpose of this research is to establish the optimal alloy design and microstructure for achieving the desired mechanical properties (tensile strength, yield strength, elongation and low temperature impact value) of key components used in large-scale windmills. In order to meet the impact requirement (I-40°C≥10J) of spec. EN-GJS-350-22U-LT, the Si content should be kept below 1.97%, and also the maximum pearlite content shouldn’t exceed 7.8%. On the other hand, the optimal alloy designs that can comply with specification EN-GJS-700-2U include 0.25%Mn+0.8%Cu+0.01%Sn , 0.25%Mn+0.6%Cu+0.05%Sn and 0.45%Mn+0.6%Cu+0.01%Sn. Furthermore, based upon the experimental results, multiple regression analyses have been performed to correlate the mechanical properties with chemical compositions and microstructures. The derived regression equations can be used to attain the optimal alloy design for castings with targeted specifications. Furthermore, by employing these regression equations, the mechanical properties can be predicted based upon the chemical compositions and microstructures of cast irons.

scholarly journals The Impact of Wood Waste Ash on Physical Mechanical Properties of Concrete

2021 ◽  
Vol 1203 (3) ◽  
pp. 032097
Author(s):  
Marija Vaiciene ◽  
Jurgita Malaiskiene
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Pulse Velocity ◽  
Capillary Water ◽  
Cement Concrete ◽  
Capillary Water Absorption ◽  
The Impact ◽  
Ultrasound Pulse

Abstract In this work is analysing the impact of wood waste bottom ash (WWBA) on the physical mechanical properties of Portland cement concrete (PCC). WWBA is a waste generated in power plants during burning forest residues to produce energy and heat. In 2019, about 19,800 tons of WWBA was generated only in Lithuania. Usually, WWBA is disposed of in landfills, only 26% of WWBA is used in the construction or maintenance of local roads, because of that it is useful to know properties of such WWBA and to analyse possibilities of using it in cement concrete. In the chemical composition of such WWBA type was fixed a big amount ~50% of CO2. It is known, that C retards cement hydration. Due to stabilisation this process, it was used in the same amounts catalyst waste from oil cracking (FCCCw), which could accelerate hydration processes. Oil refineries worldwide generate more than 800,000 tonnes of FCCCw per year, of which around 20% in Europe and it is the big problem to landfill. In the investigation the amount of Portland cement (5-20% by mass) was replaced by mentioned wastes and properties of fresh PCC (density, slump, flow diameter) and physical mechanical properties of hardened PCC (water absorption, capillary water absorption, ultrasound pulse velocity, density, compressive strength after 28 days and 2 years curing, SEM) were established. It was determined, that by increasing amount of waste (till 20%) the workability of concrete decreases, because used wastes had higher water requirement. The best results were obtained, when 5% of cement was replaced by WWBA. Then compressive strength after 28 days curing comparing to control sample decreased 8%, but after 2 years curing it increased 1%, also the capillary water absorption decreased, denser structure was formed. The obtained results of hardened PCC density, ultrasound pulse velocity and water absorption are similar to control samples.

Impact of COVID-19 on Nuclear Medicine in Germany, Austria and Switzerland: An International Survey in April 2020

2020 ◽  
Vol 59 (04) ◽  
pp. 294-299 ◽  
Author(s):  
Lutz S. Freudenberg ◽  
Ulf Dittmer ◽  
Ken Herrmann
Keyword(s):  
Nuclear Medicine ◽  
Health Systems ◽  
Personal Protective Equipment ◽  
Large Scale ◽  
Diagnostic Procedures ◽  
Protective Equipment ◽  
Current Crisis ◽  
Web Based ◽  
Public Versus Private ◽  
The Impact

Abstract Introduction Preparations of health systems to accommodate large number of severely ill COVID-19 patients in March/April 2020 has a significant impact on nuclear medicine departments. Materials and Methods A web-based questionnaire was designed to differentiate the impact of the pandemic on inpatient and outpatient nuclear medicine operations and on public versus private health systems, respectively. Questions were addressing the following issues: impact on nuclear medicine diagnostics and therapy, use of recommendations, personal protective equipment, and organizational adaptations. The survey was available for 6 days and closed on April 20, 2020. Results 113 complete responses were recorded. Nearly all participants (97 %) report a decline of nuclear medicine diagnostic procedures. The mean reduction in the last three weeks for PET/CT, scintigraphies of bone, myocardium, lung thyroid, sentinel lymph-node are –14.4 %, –47.2 %, –47.5 %, –40.7 %, –58.4 %, and –25.2 % respectively. Furthermore, 76 % of the participants report a reduction in therapies especially for benign thyroid disease (-41.8 %) and radiosynoviorthesis (–53.8 %) while tumor therapies remained mainly stable. 48 % of the participants report a shortage of personal protective equipment. Conclusions Nuclear medicine services are notably reduced 3 weeks after the SARS-CoV-2 pandemic reached Germany, Austria and Switzerland on a large scale. We must be aware that the current crisis will also have a significant economic impact on the healthcare system. As the survey cannot adapt to daily dynamic changes in priorities, it serves as a first snapshot requiring follow-up studies and comparisons with other countries and regions.

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