scholarly journals Erratum: “Material Strength: A Rational Nonequilibrium Energy Model for Complex Loadings”

2021 ◽  
pp. 1-4
Author(s):  
Jie Zhou ◽  
Biao Wang
Keyword(s):  
Energy Model ◽  
Material Strength ◽  
Printing Process ◽  
Significant Change ◽  
Nonequilibrium Energy

Abstract Some errors in the derivation and printing process in the original paper were corrected. Although it was found that the errors have not created significant change in the main conclusions, the details were still given in this paper.

Material Strength: A Rational Nonequilibrium Energy Model for Complex Loadings

2020 ◽  
Vol 88 (2) ◽  
Author(s):  
Biao Wang
Keyword(s):  
Failure Process ◽  
Strength Criterion ◽  
Energy Model ◽  
Natural Phenomenon ◽  
Material Strength ◽  
Strength Theory ◽  
Reliable Prediction ◽  
Strength Criteria ◽  
Safety Considerations ◽  
Nonequilibrium Energy

Abstract The failure of materials with some sort of loading is a well-known natural phenomenon, and the reliable prediction of the failure of materials is the most important issue for many different kinds of engineering materials based on safety considerations. Classical strength theories with complex loadings are based on some sort of postulations or assumptions, and they are intrinsically empirical criteria. Due to their simplicity, classical strength theories are still widely used in engineering, and they are very easy to incorporate into any finite element code. Recently, a new methodology was proposed by the author. Instead of establishing empirical models, the material failure process was modeled as a nonequilibrium process. Then, the strength criterion was established with the rational stability analysis for the failure process. In this study, the author tried to use this idea to develop a rational thermodynamic strength theory and to make the theory easy to use in engineering, similar to the classical strength criteria. It was found that the predictions of the rational energy strength theory were very reasonable compared to the experimental data even if no postulation was taken. Through the analysis, it seemed that the strength problem could be efficiently tackled using the rational nonequilibrium energy model instead of using some sort of empirical assumptions or models.

scholarly journals Increasing of Strength of FDM (FFF) 3D Printed Parts by Influencing on Temperature-Related Parameters of the Process

2018 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat G. Tavitov ◽  
Oleg D. Urzhumtsev ◽  
Anna H. Vakulik
Keyword(s):  
Bulk Material ◽  
Sample Surface ◽  
Fracture Load ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Temperature Conditions ◽  
Two Factors ◽  
Related Stress

This work investigates how the user-controlled parameters of the 3D printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence the structure and strength of the part. The process studied is fused filament fabrication with a desktop 3D printer and the material utilized is PLA (polylactic acid). As a characteristic of the part strength the fracture load in the case of a three-point bend and calculated related stress were used. During the printing process parts were oriented with the long side along the Z axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. During the fabrication process, temperature distribution on the sample surface was monitored with thermal imager. Sample mesostructure was analyzed using SEM. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. The influence of all the parameters can be expressed through two generalizing factors: the temperature of the previous layer and the flow efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads). It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength.

scholarly journals Increasing of Strength of FDM (FFF) 3D Printed Parts by Influencing on Temperature-Related Parameters of the Process

2018 ◽  
Author(s):  
Vladimir E. Kuznetsov ◽  
Alexey N. Solonin ◽  
Azamat G. Tavitov ◽  
Oleg D. Urzhumtsev ◽  
Anna H. Vakulik
Keyword(s):  
Bulk Material ◽  
Fracture Load ◽  
Material Strength ◽  
Thermal Imager ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Temperature Conditions ◽  
Two Factors ◽  
Related Stress ◽  
Point Bend

Current work investigates how user-controlled parameters of 3D printing process define temperature conditions on the boundary between layers of the part being fabricated and how these conditions influence structure and strength of the part. The process studied is fused filament fabrication with a desktop 3D printer and the material utilized is PLA (polylactic acid). As a characteristic of the part strength the fracture load in the case of a three-point bend and calculated related stress were used. During the printing process parts were oriented the long side along the Z axis, thus, in the bend tests, the maximum stress occurred orthogonally to the layers. During the fabrication process temperature distribution on the samples surface was monitored with thermal imager. Sample mesostructure was analyzed using SEM. The influence of the extrusion temperature, the intensity of part cooling, the printing speed and the time between printing individual layers were considered. The influence of all the parameters can be expressed through two generalizing factors: the temperature of the previous layer and the flow efficiency, determining the ratio of the amount of extruded plastic to the calculated. A regression model was proposed that describes the effect of the two factors on the printed part strength. Along with interlayer bonding strength, these two factors determine the formation of the part mesostructure (the geometry of the boundaries between individual threads). It is shown that the optimization of the process parameters responsible for temperature conditions makes it possible to approximate the strength of the interlayer cohesion to the bulk material strength.

Obesity among adults in the United States: No statistically significant change since 2003-2004

2007 ◽  
Author(s):  
Cynthia L. Ogden ◽  
Margaret D. Carroll ◽  
Margaret A. McDowell ◽  
Katherine M. Flegal
Keyword(s):  
United States ◽  
The United States ◽  
Significant Change

Presence and Possible Origin of ɛ(γ-Glutamyl)Lysine Isodipeptide in Human Plasma

1992 ◽  
Vol 67 (01) ◽  
pp. 060-062 ◽  
Author(s):  
J Harsfalvi ◽  
E Tarcsa ◽  
M Udvardy ◽  
G Zajka ◽  
T Szarvas ◽  
...  
Keyword(s):  
Human Plasma ◽  
Fibrinolytic Therapy ◽  
Normal Human Plasma ◽  
Normal Human ◽  
Hplc Technique ◽  
Significant Change

Summaryɛ(γ-glutamyl)lysine isodipeptide has been detected in normal human plasma by a sensitive HPLC technique in a concentration of 1.9-3.6 μmol/1. Incubation of in vitro clotted plasma at 37° C for 12 h resulted in an increased amount of isodipeptide, and there was no further significant change when streptokinase was also present. Increased in vivo isodipeptide concentrations were also observed in hypercoagulable states and during fibrinolytic therapy.

On the Behaviour of a Human Serum Proactivator Reacting with Streptokinase during Artificial Activation of the Fibrinolytic System

1961 ◽  
Vol 06 (03) ◽  
pp. 498-503 ◽  
Author(s):  
W Doleschel ◽  
W Auerswald
Keyword(s):  
Human Serum ◽  
Fibrinolytic System ◽  
Spontaneous Activation ◽  
Significant Change ◽  
Artificial Activation ◽  
Activator System

SummaryDuring “spontaneous” activation of a human euglobulin preparation in suitably spaced samples — while plasminogen became progressively converted into piasmin — the proactivator content was tested by addition of equal amounts of streptokinase and evaluation of the lytic activities on heated and normal bovine fibrin plates. Indepedently of the decreasing content of plasminogen the proactivator which could be activated by streptokinase showed no significant change of concentration. These observation indicate that plasminogen is not acting as proactivator and that there exists a separate proactivator-activator system of the fibrinolytic mechanism in human serum.

Analisis Daya Dukung Tanah Dan Bahan Pondasi Tiang Pancang Pada Pembangunan Jembatan Kab. Jombang

2020 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Ruslan Hidayat ◽  
Saiful Arfaah
Keyword(s):  
Carrying Capacity ◽  
Pile Foundation ◽  
Heavy Traffic ◽  
Traffic Volume ◽  
Material Strength ◽  
Cone Penetrometer ◽  
The Village

One of the most important factors in the structure of the pile foundation in the construction of the bridge is the carrying capacity of the soil so as not to collapse. Construction of a bridge in the village of Klitik in Jombang Regency to be built due to heavy traffic volume. The foundation plan to be used is a pile foundation with a diameter of 50 cm, the problem is what is the value of carrying capacity of soil and material. The equipment used is the Dutch Cone Penetrometer with a capacity of 2.50 tons with an Adhesion Jacket Cone. The detailed specifications of this sondir are as follows: Area conus 10 cm², piston area 10 cm², coat area 100 cm², as for the results obtained The carrying capacity of the soil is 60.00 tons for a diameter of 30 cm, 81,667 tons for a diameter of 35 cm, 106,667 tons for a diameter of 40 cm, 150,000 tons for a diameter of 50 cm for material strength of 54,00 tons for a diameter of 30 cm, 73,500 tons for a diameter of 35 cm, 96,00 tons for a diameter of 40 cm, 166,666 tons for a diameter of 50 cm

ANALISIS RASIO UNTUK MENGUKUR KINERJA KEUANGAN PERUSAHAAN (STUDI KASUS PADA PT MEKAR KARYA PRATAMA)

2019 ◽  
Vol 9 (1B) ◽  
pp. 15
Author(s):  
Rizki Ahmad Fauzi
Keyword(s):  
Financial Performance ◽  
Financial Statements ◽  
Corporate Activity ◽  
Significant Change ◽  
Overall Ratio ◽  
The Impact ◽  
Solvency Ratio

Based on the results of the analysis of the ratio of the financial statements can be seen from liquidity ratio in 2010 can already be said to be liquid and in 2011 occurred very significant increase in this ratio that makes the company's liquidity to be too high. Judging from the solvency ratio, in 2010 the company could not be said solvable because the value of this ratio is still quite high. However, in 2011 this ratio decreased significantly which shows that the company can already be said to be solvable. From the ratio of the activity, in 2010 and 2011 the ratio of corporate activity can already be said to be good. Despite the decrease from 2010 to 2011 on some of these ratios, but the overall ratio of activity of the company is good enough. Judging from the ratio of profitability, in 2010 and 2011 the profitability of the company can not be said to be good because it is still very low and no significant change from the year 2010 to the year 2011 for this ratio.The overall financial performance of PT Mekar Karya Pratama from year 2010 to year 2011 can be said to be good, although there are some things that must be considered and they should be repaired as liquidity is too high which causes the idle funds and the impact on the profitability is low. Keyword:Rasio Analysis

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