Characterization of Effective Parameters in Abrasive Waterjet Rock Cutting

In order to boost the electromechanical coupling factor and decrease the characteristic impedance, a 1-3 piezoelectric composite with a 3-tier polymer structure was designed and fabricated, in which epoxy resin constitutes the middle layer and silicone rubber is used to clamp the epoxy. The effective parameters of the composite, such as resonant frequency, electromechanical coupling factor, and characteristic impedance, were studied by the finite element method and experiment. The experimental results indicate that the electromechanical coupling factor of the composite is enhanced by 8.4% and the characteristic impedance is decreased by 52.8%, compared with the traditional 1-3 ceramic/epoxy composite.

Download Full-text

Characterization of Bulk BaTiO3 Material for Optical Modulator Applications

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1002.132 ◽

2020 ◽

Vol 1002 ◽

pp. 132-139

Author(s):

Sabah Al-Ithawi ◽

Wasan A. Hekmat ◽

Kadhim A. Hubeatir ◽

Shams B. Ali ◽

Suad M. Kadhim ◽

...

Keyword(s):

Sample Size ◽

Crystalline Structure ◽

Figure Of Merit ◽

Optical Modulator ◽

Effective Parameters ◽

Good Efficiency ◽

Half Wave Voltage ◽

Half Wave ◽

Electro Optic

In this work, different sizes of BaTiO3 (BTO) were characterized. The effective parameters were studied to reach optimum performance in order to realize an optical modulator. The parameters such as spectroscopy, electro-optic coefficient, crystalline structure, and birefringence indicated that BaTiO3 has an excellent behavior to manipulate the light by Pockels modulator, spatially in the field of telecom. The sample size (10×3 mm) was shown a good performance compare with other samples, for example, the BTO has low absorption, high variation of output as a function of voltage applied and good efficiency that showed by figure of merit. In addition, a low half-wave voltage (Vπ) was observed.

Download Full-text

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0380 ◽

2020 ◽

Vol 98 (12) ◽

pp. 755-763

Author(s):

Hamid Reza Ghayeni ◽

Reza Razeghi ◽

Abolfazl Olyaei

Keyword(s):

Uv Light ◽

Light Exposure ◽

Sodium Acrylate ◽

Spectroscopic Techniques ◽

Effective Parameters ◽

X Ray Diffraction ◽

X Ray ◽

Cds Nanorods ◽

Transmission Electron

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

Download Full-text

Preparation and Processing Characterization of Glass/Phenolic Prepregs

Polymers and Polymer Composites ◽

10.1177/096739111101900909 ◽

2011 ◽

Vol 19 (9) ◽

pp. 789-796 ◽

Cited By ~ 2

Author(s):

Mohammad Rajaei ◽

Mohammad Hosain Beheshty ◽

Mehran Hayaty

Keyword(s):

Differential Scanning Calorimetry ◽

Phenolic Resin ◽

Flexural Modulus ◽

Resin Flow ◽

Effective Parameters ◽

Scanning Calorimetry ◽

Cure Cycle ◽

Cure Behaviour ◽

Structural Parts

Glass/phenolic prepreg is one of the most applicable prepregs used for making composites for structural parts. To investigate the effective parameters on the processing and properties of these prepregs, thirty samples of glass/phenolic prepregs containing about 50 wt.% resins were prepared by using a resole type phenolic resin and satin glass fibre fabric. They were B-staged or pre-cured at 110 °C and 120 °C for different times from 15 to 50 min, to control the flow behaviour and tack properties. Tack and resin flow were characterized, in order to determine the conditions in which flow and tack properties are optimum. Results show that the levels of pre-cure or conversion were between 2% and 55%. The maximum tack was achieved at 5.3% conversion. Cure behaviour and rheological properties of these prepregs were studied by using differential scanning calorimetry and rheometry. An appropriate cure cycle is presented with the aid of these results. After curing the prepregs on the basis of this cure cycle, a flexural strength of 172.6 MPa and flexural modulus of 17 GPa were obtained.

Download Full-text

Effects of Focus Geometry on the Hard Rock-Cutting Performance of an Abrasive Waterjet

Advances in Civil Engineering ◽

10.1155/2020/1650914 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Yohan Cha ◽

Tae-Min Oh ◽

Gye-Chun Cho

Keyword(s):

Momentum Transfer ◽

Hard Rock ◽

Empirical Relationship ◽

Abrasive Particle ◽

Rock Cutting ◽

Maximum Energy ◽

Cutting Performance ◽

Granitic Rocks ◽

Abrasive Waterjet ◽

Cutting Depth

Abrasive waterjets are being increasingly used in civil engineering for rock and concrete cutting, particularly for the demolition or repair of old structures. The energy of an abrasive waterjet is primarily provided by the accelerated abrasive. The momentum transfer during mixing and acceleration determines the abrasive velocity, which affects the cutting performance. Meanwhile, the geometry of the focus at which mixing occurs influences the momentum transfer efficiency. In this study, the effects of the focus geometry on the optimum abrasive flow rate (AFR) and momentum transfer characteristics in hard rock cutting were investigated. Experiments were conducted using granite specimens to test the AFR under different focus geometry conditions such as diameter and length. The results show that the focus geometry significantly affects the maximum cutting depth and optimum AFR. The maximum cutting energy was analyzed based on the cutting efficiency of a single abrasive particle. In addition, the momentum transfer parameter (MTP) was evaluated from the empirical relationship between the maximum energy and the cutting depth for granitic rocks. Accordingly, a model for estimating the MTP based on the AFR was developed. It is expected that the results of this study can be employed for the optimization of waterjet rock cutting.

Download Full-text

Effects of geometric parameters of a combined nozzle for rock cutting using an abrasive waterjet

Journal of Korean Tunnelling and Underground Space Association ◽

10.9711/ktaj.2012.14.5.517 ◽

2012 ◽

Vol 14 (5) ◽

pp. 517-528 ◽

Cited By ~ 3

Author(s):

Tae-Min Oh ◽

Gye-Chun Cho

Keyword(s):

Rock Cutting ◽

Geometric Parameters ◽

Abrasive Waterjet

Download Full-text

Artificial neural network and regression models for performance prediction of abrasive waterjet in rock cutting

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-014-6211-y ◽

2014 ◽

Vol 75 (9-12) ◽

pp. 1321-1330 ◽

Cited By ~ 35

Author(s):

Gokhan Aydin ◽

Izzet Karakurt ◽

Coskun Hamzacebi

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Performance Prediction ◽

Regression Models ◽

Rock Cutting ◽

Abrasive Waterjet ◽

Artificial Neural

Download Full-text

Seismic inversion for the parameters of two orthogonal fracture sets in a VTI background medium

Geophysics ◽

10.1190/1.1451801 ◽

2002 ◽

Vol 67 (1) ◽

pp. 292-299 ◽

Cited By ~ 29

Author(s):

Andrey Bakulin ◽

Vladimir Grechka ◽

Ilya Tsvankin

Keyword(s):

Seismic Data ◽

Fractured Reservoirs ◽

Crack Density ◽

Transversely Isotropic ◽

Seismic Inversion ◽

Naturally Fractured Reservoirs ◽

Multiple Fracture ◽

Effective Parameters ◽

Wide Range

Characterization of naturally fractured reservoirs often requires estimating parameters of multiple fracture sets that develop in an anisotropic background. Here, we discuss modeling and inversion of the effective parameters of orthorhombic models formed by two orthogonal vertical fracture sets embedded in a VTI (transversely isotropic with a vertical symmetry axis) background matrix. Although the number of the microstructural (physical) medium parameters is equal to the number of effective stiffness elements (nine), we show that for this model there is an additional relation (constraint) between the stiffnesses or Tsvankin's anisotropic coefficients. As a result, the same effective orthorhombic medium can be produced by a wide range of equivalent models with vastly different fracture weaknesses and background VTI parameters, and the inversion of seismic data for the microstructural parameters is nonunique without additional information. Reflection moveout of PP‐ and PS‐waves can still be used to find the fracture orientation and estimate (in combination with the vertical velocities) the differences between the normal and shear weaknesses of the fracture sets, as well as the background anellipticity parameter ηb. Since for penny‐shaped cracks the shear weakness is close to twice the crack density, seismic data can help to identify the dominant fracture set, although the crack densities cannot be resolved individually. If the VTI symmetry of the background is caused by intrinsic anisotropy (as is usually the case for shales), it may be possible to determine at least one background anisotropic coefficient from borehole or core measurements. Then seismic data can be inverted for the fracture weaknesses and the rest of the background parameters. Therefore, seismic characterization of reservoirs with multiple fracture sets and anisotropic background is expected to give ambiguous results, unless the input data include measurements made on different scales (surface seismic, borehole, cores).

Download Full-text