scholarly journals Seasonal Freezing of a Logging Dirt Road: Modeling of Conditions of Transverse Cracks Emergence

2018 ◽  
Vol 3 (15) ◽  
pp. 29-42 ◽  
Author(s):  
Timmo Gavrilov ◽  
Konstantin Khoroshilov ◽  
Gennadii Kolesnikov
Keyword(s):  
Transverse Cracks ◽  
Seasonal Freezing ◽  
Dirt Road

Cement Content of Durability Cement Stabilized Macadam Base Course in Seasonal Freezing Zone

CICTP 2020 ◽  
2020 ◽  
Author(s):  
Junchen Ma ◽  
Chunyu Liang ◽  
Ying Wang ◽  
Lidong Zhang ◽  
Weiwu Cui ◽  
...  
Keyword(s):  
Cement Content ◽  
Seasonal Freezing ◽  
Base Course

scholarly journals Non-destructive ultrasonic tomography for concrete pavement evaluation: signal processing and image analysis of crucial parameters

2017 ◽  
Vol 10 (6) ◽  
pp. 1182-1191
Author(s):  
L. S. SALLES ◽  
J. T. BALBO ◽  
L. KHAZANOVICH
Keyword(s):  
Signal Processing ◽  
Concrete Slab ◽  
Low Frequency ◽  
Concrete Pavement ◽  
Ultrasonic Tomography ◽  
Transverse Cracks ◽  
Pavement Maintenance ◽  
Use Of Technology ◽  
Pavement Evaluation ◽  
Non Destructive

Abstract In recent years, due to the destructive and unproductive character of pavement specimen extraction, pavement maintenance technology intensified the use of non-destructive techniques for pavement evaluation which resulted in the development of several devices and evaluation methods. This paper describes the use of technology based on low frequency ultrasonic tomography for evaluation of concrete pavement parameters. The equipment was applied in three experimental sections with different concrete pavements built at the University of Sao Paulo campus. The ultrasonic signal processing is given. The results analysis enables the efficient and reliable identification of thickness and reinforcement position within the concrete slab. Construction problems were evidenced in one of experimental sections with thickness deficiencies and reinforcement in a position below projected. Furthermore, the use of a novel concrete quality indicator was correlated with the presence of transverse cracks and alkali-silica reaction within the sections.

Crack Formation Mechanism of High Silicon Steel during Twin-Roll Strip Casting

2017 ◽  
Vol 898 ◽  
pp. 1276-1282
Author(s):  
Wen Li Hu ◽  
Yuan Xiang Zhang ◽  
Guo Yuan ◽  
Guo Dong Wang
Keyword(s):  
Formation Mechanism ◽  
Crack Formation ◽  
Silicon Steel ◽  
Strip Casting ◽  
Dominant Factor ◽  
Transverse Cracks ◽  
High Silicon Steel ◽  
High Silicon ◽  
Gas Gap ◽  
Twin Roll

High silicon steel was fabricated by twin-roll strip casting. The cracks on the surfaces of the processed strips were obtained and analyzed by digital camera after series of surface treatment. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to observe and characterize the microstructure nearby crack and fracture surface along the normal direction, respectively, and the crack formation mechanism was further analyzed in conjunction with processing parameters utilized during twin-roll strip casting process. The results indicated that morelongitudinal cracks along the rolling direction were observed in comparison with transverse cracks along the transverse direction on the strip surfaces. Trans granular and intergranular fracture modes both worked during the formations of longitudinal and transverse cracks on the processed strips. The dominant factor causing the formation of crack on the surface of the processed strips was the inhomogeneous transfer of heat during casting and rolling. The inhomogeneous transfer of heat induced by gas gap during casting resulted in variations of dendrite length and secondary dendrite spacing (SDAS). Meanwhile, the casting velocity influenced the formation of gas gap, which further influenced the thermal contraction. So the control of velocity of casting above a certain level proved beneficial to enhancing the performance of strip casting and to improving the quality of strip products.

scholarly journals Territory size of three Antbirds (Aves, Passeriformes) in an Atlantic Forest fragment in southeastern Brazil

2006 ◽  
Vol 23 (3) ◽  
pp. 692-698 ◽  
Author(s):  
Charles Duca ◽  
Tadeu J. Guerra ◽  
Miguel Â. Marini
Keyword(s):  
Forest Edge ◽  
Neotropical Region ◽  
Bird Communities ◽  
Territory Size ◽  
Southeastern Brazil ◽  
Forest Fragment ◽  
Dirt Road ◽  
Forested Landscapes ◽  
Pyriglena Leucoptera ◽  
Polygon Method

Territory size is an important ecological attribute of populations that has been considered a factor determines population density. Antbirds is a large group of mainly insectivorous Neotropical passerines, usually well represented in bird communities from forested landscapes in Neotropical region. Territory sizes for three Antbirds, Thamnophilus caerulescens (Vieillot, 1816) (Variable Antshrike), Dysithamnus mentalis (Temmink, 1823) (Plain Antvireo) e Pyriglena leucoptera (Vieillot, 1818) (White-shouldered Fire-eye), were mapped and their area estimated by the convex polygon method in a 50 ha forest fragment, in southeastern Brazil. The three species presented small territories of similar sizes (< 2 ha) both during the non-reproductive and the reproductive seasons of 2000-2001. Territories overlapped considerably among species but not intraspecifically. Territory sizes increased with body mass of the three species studied (P. leucoptera > T. caerulescens > D. mentalis). We failed to find any effect on territory size for the three species associated with forest edge or distance to the dirt road.

Influence of Transverse Cracks on Ultimate Strength of a Steel Plate Under Compression

2011 ◽  
Author(s):  
Abbas Bayatfar ◽  
Jerome Matagne ◽  
Philippe Rigo
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Transverse Cracks ◽  
Longitudinal Compression ◽  
Initial Imperfections ◽  
Crack Location ◽  
Linear Finite Element ◽  
Newton Raphson ◽  
Raphson Method

This study has been carried out on ultimate compressive strength of a cracked steel plate component, considering the effects of initial imperfections (transverse and longitudinal residual stresses and initial deflection, as well). The main objective of this paper is to numerically investigate the influence of crack location and crack length on ultimate strength of a steel plate under monotonic longitudinal compression. This investigation is performed through non-linear finite element (FE) analysis using ANSYS commercial finite element code in which is employed Newton-Raphson method. The FE results indicate that the length of transverse crack and especially its location can significantly affect the magnitude of ultimate strength where the steel plate is subjected to longitudinal compressive action.

INVESTIGATION OF TRANSVERSE CRACKS IN ANNULAR WELDED JOINTS OF MAIN GAS PIPELINES LINEAR PART

2021 ◽  
pp. 34-41
Author(s):  
V. A. Zaznobin ◽  
A. V. Nekrasov ◽  
A. V. Pankratov
Keyword(s):  
Welded Joints ◽  
Linear Part ◽  
Correct Identification ◽  
Gas Pipelines ◽  
Destructive Testing ◽  
Transverse Cracks ◽  
Additional Control ◽  
Non Destructive

Statistics of accidents and incidents on main gas pipelines in recent years indicate that almost half of the technogenic events occur due to depressurization in the area of annular welded joints, mainly joints containing defects made during construction and installation work during the construction of gas pipelines. The assessment of the degree of danger and the timing of external inspection and repair or replacement of defective annular welded joints largely depends on the quality of non-destructive testing, the correct identification of the types of defects and the objective determination of their geometric dimensions. To increase the reliability of the assessment of the degree of danger of the detected defects, it is necessary to use additional control methods, in particular, destructive ones. The paper presents the results of surveys and tests of metal fragments of annular welded joints of main gas pipelines containing transverse cracks of annular welded joints in order to determine the causes of the formation of these defects and to assess the degree of danger of the detected transverse cracks of the installation welds of main gas pipelines.

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