Methodology of Technological Adaptation Applied to Powder Rolling

2018 ◽  
Vol 779 ◽  
pp. 174-180
Author(s):  
Marina Polyakova ◽  
Eduard Golubchik
Keyword(s):  
Hydrostatic Stress ◽  
Powder Rolling ◽  
Rolled Strip ◽  
Green Density ◽  
Central Ring ◽  
Technological Adaptation ◽  
Maximum Value ◽  
Roll System ◽  
High Level ◽  
New Criterion

Powder rolling is used for manufacturing long-length strip. For obtaining the product with high green density it is necessary to ensure shear strain in the deformation zone. Based on the principles of technologic adaptation the dual roll closed caliber with adaptively changed rigidity was constructed. It consists of upper bandage with shoulder, bottom bandage with groove in which the set of three rings (two aside and one central) is located. The pass is arranged by aside rings and outside surface of the central ring forming closed caliber while interacting with the shoulder of the upper bandage. The caliber output is equal to zero and the broadening at rolling is fully excluded. Such construction of the tool makes it possible to achieve high level of hydrostatic stress of tensor simultaneously with intensification of shear strains resulting in practically nonporous rolled strip. Taking into consideration peculiarities of calibre rolling the new criterion was proposed. This criterion enables to characterize roll system for each material, incompact materials in particular, considering retraction ability, to assess and identify the final square of the rolled material at different caliber configuration. Dependence of maximum value of powdered rolled strip thickness on dual roll closed caliber retraction surface value at different rolled strip width is presented.

On the Effect of the Incident Mach’s Wave on the Pulsation Level in Boundary Layer of the Plane Delta Wing

2014 ◽  
Vol 9 (1) ◽  
pp. 29-38
Author(s):  
Aleksandr Vaganov ◽  
Yuri Yermolaev ◽  
Gleb Kolosov ◽  
Aleksandr Kosinov ◽  
Aleksandra Panina ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Mass Flow ◽  
Delta Wing ◽  
Level Fluctuation ◽  
Flow Pulsation ◽  
Flow Conditions ◽  
Wing Model ◽  
Maximum Value ◽  
Leading Edges ◽  
High Level

The experimental results of high level fluctuation excitation by external Mach’s wave in the boundary layer of delta wing model with blunt leading edges at Mach numbers M = 2, 2.5, 4 are presented. The exitation areas and mass flow pulsation levels in the conditions of subsonic, sonic and supersonic leading edges have been defined. It was found that the maximum value of the pulsations is 12–15 % and varies only slightly from the flow conditions around of the delta wing

The chromian spinels of the Lyavaraka ultrabasic complex, Serpentinite Belt, Kola Peninsula, Russia: Patterns of zoning, hypermagnesian compositions, and early oxidation

2021 ◽  
Vol 59 (6) ◽  
pp. 1693-1709
Author(s):  
Andrei Y. Barkov ◽  
Andrey A. Nikiforov ◽  
Vladimir N. Korolyuk ◽  
Larisa P. Barkova ◽  
Robert F. Martin
Keyword(s):  
Kola Peninsula ◽  
First Generation ◽  
Ferric Iron ◽  
Chromian Spinel ◽  
Maximum Value ◽  
Two Generations ◽  
High Level ◽  
A Minor ◽  
Compositional Series ◽  
Minor Quantity

ABSTRACT The maximum value of Mg# [= 100Mg/(Mg + Fe2+ + Mn)] in chromium-bearing spinel-group minerals (Chr) in the Ultrabasic Core Zone (UCZ) of the Lyavaraka orthopyroxenite – harzburgite – dunite complex of the Serpentinite Belt in the Kola Peninsula is 54.5–67.5. Such highly magnesian compositions of spinel are associated with notable enrichments of ferric iron (Fe3+# 58–63). There are two generations of accessory Chr in the UCZ unit. The first generation occurs as inclusions in olivine that is not unusually magnesian (Mg# 90.3), and the second is closely associated with serpentine. The compositional series of Chr at Lyavaraka attains more aluminous compositions than was observed in nearby intrusive bodies. The anomalously high level of Mg in Chr, also manifest in ilmenite, is mainly a result of the high intrinsic fugacity of oxygen attained locally in the melt. A progressive buildup in H2O and increase in fO2 likely resulted from efficient vesiculation and selective loss of H2 from the Al-undepleted komatiitic magma crystallizing in a shallow setting. The chromian spinel forming in such a modified magma is virtually unzoned in Mn, and a minor quantity of Mn is also present in olivine and orthopyroxene. In contrast, zinc is strongly partitioned in the core of Chr, as it is relatively incompatible in the coexisting olivine and orthopyroxene at that stage. Zinc efficiently partitioned into the H2O-enriched melt, which crystallized as the pegmatitic orthopyroxenite near the contacts at Lyavaraka. A high potential of oxidation appears to be characteristic of all orthopyroxenite – harzburgite – dunite suites of the Serpentinite Belt formed from a primitive melt of komatiitic composition.

Proposal of the Local Failure Evaluation Method With Stress Parameters

2018 ◽  
Author(s):  
Takashi Sakaguchi ◽  
Mizuki Yoshida ◽  
Takuya Sato ◽  
Naoto Kasahara
Keyword(s):  
Fracture Surface ◽  
Evaluation Method ◽  
Hydrostatic Stress ◽  
Notch Root ◽  
Local Failure ◽  
Dominant Factor ◽  
Multiaxial Stress ◽  
Minimum Diameter ◽  
Nuclear Plants ◽  
New Criterion

The failure mode known as local failure could occur at structure discontinuities with multiaxial stress conditions. Experiments and analyses of notched bars, which generate multiaxial stress, were conducted. The experiments showed that the tensile strength of a notched bar was stronger than that of a smooth bar. The ratio of the maximum and minimum diameter has become the important factor of this notch strengthening. In addition, the initiation of failure was observed at the inner location from the notch root. According to the analysis results, the Mises-stress became the maximum at the notch root. On the other hand, hydrostatic stress became the maximum at the inner location from the notch root, and this location corresponded to the initiation of fracture. The maximum hydrostatic stress has good correlation with the notch strengthening ratio. These facts reveal that hydrostatic stress must be taken into account for strength evaluation as a dominant factor in addition to the Mises-stress. However, only Mises-stress is considered in the present structural design code of nuclear plants. From above results, the new criterion based on fracture surface, where the coordinate plane consists of hydrostatic stress and Mises-stress, was proposed for local failure. Furthermore, this fracture surface was extended to an isochronous fracture surface in a creep region based on isochronous stress-strain curves.

Effect of Binder Content on the Slip Rheology and Green Properties of Slip Cast Alumina

2019 ◽  
Vol 798 ◽  
pp. 177-181
Author(s):  
Kritkaew Somton ◽  
Pitak Laoratanakul ◽  
Ryan McCuiston
Keyword(s):  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
Casting Process ◽  
Binder Content ◽  
Green Density ◽  
Optimal Amount ◽  
Solids Loading ◽  
Maximum Value ◽  
Slip Cast ◽  
Scanning Electron

The rheology of A96% alumina slips and the physical and mechanical properties of slip cast samples were studied. The slips had a constant solids loading of 40 wt% alumina and a polyvinyl alcohol (PVA) content of 0-3 wt%, as a binder. The rheological behavior and viscosity of the slips were examined to determine the flowability of the slips necessary for the casting process. The slips were prepared by ball milling and the bend bar samples were cast in plaster molds. The green densities and the flexural strength of the bars were measured, and the fracture surfaces were examined by scanning electron microscopy. It was found that the slip viscosity increased with an increase of PVA content. The green flexural strength also increased to a maximum value of 0.52 MPa with increasing PVA up to 2 wt%. The further addition of PVA decreased the flexural strength. The green density did not significantly change with the PVA content, however the samples produced using 3 wt% PVA showed the lowest percentage of theoretical density of 41%. The fracture surface of the 3 wt% PVA sample showed numerous large pores compared with the other samples. Therefore, in this study it was concluded that there is in optimal amount of PVA to produce the highest green density and flexural strength of cast samples. Excess PVA reduced the flowability of the slip and resulted in excess porosity, which decreased the green density and deteriorated the flexural strength.

A Generalized von Mises Criterion for Yield and Fracture

1980 ◽  
Vol 47 (2) ◽  
pp. 297-300 ◽  
Author(s):  
W. H. Yang
Keyword(s):  
Bauschinger Effect ◽  
Hydrostatic Stress ◽  
Fracture Criteria ◽  
Deformation History ◽  
Von Mises Criterion ◽  
Effect On Yield ◽  
Von Mises ◽  
New Criterion ◽  
Physical Phenomena ◽  
Special Case

Yield and fracture criteria for real materials are to a varying degree affected by a state of hydrostatic stress. Some materials, after certain deformation history, exhibit different yield point when the direction of the stress is reversed, a behavior known as the Bauschinger effect. These physical phenomena are not represented by the von Mises criterion. Based on a convexity theorem of matrices, a generalization of the von Mises criterion is presented. The new criterion satisfies the convexity requirement of plasticity theory and, with two scalar functions of deformation history α and β, produces a class of hardening behavior. The current values of α and β account for the effect of hydrostatic stress and an aspect of the Bauschinger effect on yield and fracture. The generalized criterion reduces to the form of the von Mises criterion as a special case.

Soil gas CO2 emissions and fault locking along the Anninghe fault and the Zemuhe fault, in China Seismic Experimental Site

2020 ◽  
Author(s):  
Ying Li ◽  
Yao Yang ◽  
Zhi Chen
Keyword(s):  
Active Faults ◽  
Soil Gas ◽  
Dislocation Model ◽  
Experimental Site ◽  
Maximum Value ◽  
High Level ◽  
Fault Locking ◽  
First Time ◽  
Northern Segment ◽  
Anninghe Fault

<p>The Anninghe fault (ANHF) and the Zemuhe fault (ZMHF) with high level of seismic hazards in the China Seismic Experimental Site, located in southeastern of Tibet, are some of the most active faults in China. Measurement of the soil gas CO<sub>2</sub> has been conducted in three sites along the ANHF and the ZMHF for the first time. Totally, 394 sampling points along 15 profiles were measured. The fault locking degree of different segments of the ANHF and the ZMHF were inverted by the negative dislocation model using GPS velocity data  since 2013 to 2017. The measurements results show that the average and maximum value of CO<sub>2</sub> in the ZMHF is significantly higher than that in the ANHF. Soil gas CO<sub>2</sub> geochemistry yielded different spatial anomalous features, indicating the different properties and permeability of the faults. The inversion results reveal that the level of coupling including the locking depth and intensity along the southern segment of the ANHF was significantly larger than the northern segment of the ZMHF. Combining the CO<sub>2</sub> emission results, we concluded that the intensive locking of the segments reduced their permeability due to the self-sealing process, results in less gas to escape from the deep. Correspondingly, the creeping fault with low level of coupling can maintain high permeability which is more favorable to gas CO<sub>2</sub> migration.</p>

scholarly journals A new criterion for determining the representative elementary volume of translucent porous media and inner contaminant

2020 ◽  
Author(s):  
Ming Wu ◽  
Jianfeng Wu ◽  
Jichun Wu ◽  
Bill X. Hu
Keyword(s):  
Coefficient Of Variation ◽  
Light Transmission ◽  
Interfacial Area ◽  
Representative Elementary Volume ◽  
Elementary Volume ◽  
Effective Parameters ◽  
Entropy Dimension ◽  
High Level ◽  
Random Fluctuations ◽  
New Criterion

Abstract. Representative elementary volume (REV) is essential to measure and quantify the effective parameters of a complex heterogeneous medium. Since previous REV estimation criteria having multiple limitations, a new criterion (χi) is proposed to estimate REV of a translucent material based on light transmission techniques. Two sandbox experiments are performed to estimate REVs of porosity, density, tortuosity and perchloroethylene (PCE) plume using multiple REV estimation criteria. In comparison with χi, previous REV estimation criteria based on the coefficient of variation (CVi), the entropy dimension (DIi) and the relative gradient error (εgi) are tested in REV quantification of translucent silica and inner PCE plume to achieve their corresponding effects. Results suggest that new criterion (χi) can effectively identify the REV in the materials, whereas the coefficient of variation (CVi) and entropy dimension (DIi) cannot. The relative gradient error (εgi) can make the REV plateau obvious, while random fluctuations make the REV plateau uneasy to identify accurately. Therefore, the new criterion is appropriate for REV estimation for the translucent materials and inner contaminant. Models are built based on Gaussian equation to simulate the distribution of REVs for media properties, which frequency of REV is dense in the middle and sparse on both sides. REV estimation of PCE plume indicates high level of porosity lead to large value of mean and standard deviation for REVs of PCE saturation (So) and PCE-water interfacial area (AOW). Fitted equations are derived for distribution of REVs for PCE plume related to dm (distances from mass center to considered point) and dI (distances from injection position to considered point). Moreover, relationships between REVs of PCE plume and So are fitted using regression analysis. Results suggest a decreasing trend appears for So-REV when So increases, while Aow-REV increases with increasing of So.

Improving Human Activity Recognition in Smart Homes

2015 ◽  
Vol 6 (3) ◽  
pp. 19-37 ◽  
Author(s):  
M'Hamed Bilal Abidine ◽  
Lamya Fergani ◽  
Belkacem Fergani ◽  
Anthony Fleury
Keyword(s):  
Human Activity ◽  
Conditional Random Fields ◽  
Imbalanced Data ◽  
Support Vector ◽  
Svm Classifier ◽  
Linear Discriminant ◽  
Previous State ◽  
High Level ◽  
The Cost ◽  
New Criterion

Even if it is now simple and cheap to collect sensors information in a smart home environment, the main issue remains to infer high-level activities from these simple readings. The main contribution of this work is twofold. Firstly, the authors demonstrate the efficiency of a new procedure for learning Optimized Cost-Sensitive Support Vector Machines (OCS-SVM) classifier based on the user inputs to appropriately tackle the problem of class imbalanced data. It uses a new criterion for the selection of the cost parameter attached to the training errors. Secondly, this method is assessed and compared with the Conditional Random Fields (CRF), Linear Discriminant Analysis (LDA), k-Nearest Neighbours (k-NN) and the traditional SVM. Several and various experimental results obtained on multiple real world human activity datasets using binary and ubiquitous sensors show that OCS-SVM outperforms the previous state-of-the-art classification approach.

scholarly journals Study the Effect of Blade Angles on the Performance of Axial Six Blades Wind Turbine

2018 ◽  
Vol 7 (4.19) ◽  
pp. 945
Author(s):  
Mishaal A AbdulKareem ◽  
Ammar A Hussain ◽  
Raid S Fahad
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Operating Conditions ◽  
Power Coefficient ◽  
Maximum Value ◽  
Speed Range ◽  
Electrical Generator ◽  
Flow Through ◽  
High Level ◽  
Good Agreement

In this paper, the performance of a six blades axial type wind turbine has been studied experimentally to estimate the wind power, the electrical generated power and-the modified power-coefficient of the wind-turbine. This study was conducted under different operating conditions assuming steady-state, incompressible and isothermal air flow through the wind-turbine. The range of operating condition was (2 to 5.6 m/s wind speed), (10% to 100% of electrical load that is applied on the terminals of the electrical generator) and (10° to 80° blades angle of the wind-turbine). A good agreement was obtained when comparing the results of the present work with those of a previously published article. The predicted results showed that increasing the wind speed and-the blades angle of the wind-turbine will increase the generated power from the wind-turbine. The maximum-value of the modified power-coefficient was (0.57) at a wind velocity value of (5.6 m/s) and at a blades angle value of (80°). It is found that it’s not recommended to operate the wind-turbine at (80°) blades angle associated with a wind speed range that is above (3.8 m/s) due to a high level of wind-turbine vibration. 

scholarly journals Theories of Economic Fluctuations and their Influence on the Formation of the Modern Paradigm of Economic Activity of Enterprises

2020 ◽  
pp. 5-8
Author(s):  
N. Kashchena ◽  
Keyword(s):  
Economic Activity ◽  
Management System ◽  
Economic Behavior ◽  
Economic Fluctuations ◽  
Business Activity ◽  
Maximum Value ◽  
The Business Cycle ◽  
Business Entities ◽  
High Level ◽  
Internal And External Factors

The article is devoted to the substantiation of the influence of the theory of economic fluctuations on the economic activity of enterprises. The influence of economic fluctuations at the macrolevel of the economy on economic activity at the microlevel of business entities is noted. A systematic approach to determining the economic activity of the enterprise as a phenomenon with a complex internal structure is analyzed in detail. Peculiarities of determining the effect of systematization in the interaction of components of business activity of the enterprise are analyzed: economic, managerial, financial, innovative, investment, marketing, labor, production. Attention is focused on the main goal in the management of the business activity of the enterprise as the formation of all types of activity at the exit from the system – it can be achieved by purposefully ensuring the activity of the enterprise both at the entrance to the system and in the process of transformation. The phases of formation of economic activity of the enterprise according to the theory of economic fluctuations are separated: formation; growth; maximum value; reduction. It is proved that at each phase of the business cycle the economic behavior of the enterprise changes. The urgency of measures to assess economic activity in the system of assessing the overall business activity of economic entities has been stated. The internal and external factors influencing the change of economic activity of the enterprise are defined. The importance of assessing the activity of the enterprise in the management system of economic activity as a system of "entrance-exit" of the relevant indicators is considered. The formation of control and managed subsystems in the mechanism of management of economic activity of enterprises in market conditions is analyzed. The main result of the study is the development of a management system of economic activity as a component of business activity of enterprises. Effective recommendations to ensure a high level of economic activity of enterprises in an unstable market environment are provided.

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