Preferred Plane Research Articles

Optical dispersion analysis of template assisted 1D-ZnO nanorods for optoelectronic applications

Morphology and size play crucial influential roles in semiconductor nanotechnology. Capping agents have been adopted in this study for controlled fabrication of symmetrical zinc oxide (ZnO) nanostructures, with a preferred orientation and agglomeration inhibition. Elongated one-dimensional (1D) ZnO nanorods were successfully synthesised in a simple two-step process. X-ray diffraction (XRD) revealed high crystalline films with a preferred (002) plane orientation. Ethylene glycol (EG) surfactant was found to produce substantial effect on both the morphology and crystallinity as relatively small uniform nanorods with crocked ends were observed from morphological analysis. All the synthesised ZnO films depicted optical transmittance of over 50% in the visible range and a strong absorption peak in the UV proximity, at 380 nm. An evaluation of the optical parameters calculated from the measured transmittance indicated that surfactants can be used to modify the refractive index, real and imaginary dielectric constants of ZnO nanorods, to optimize the performance of optoelectronic devices.

Geodetic Source Modeling of the 2019 Mw 6.3 Durrës, Albania, Earthquake: Partial Rupture of a Blind Reverse Fault

AbstractWe address geometric and kinematic properties of the Mw 6.3 26 November 2019 Durrës earthquake, the strongest earthquake in Albania in the past 40 years. Using coseismic surface displacements from Sentinel‐1 Differential Interferometric Synthetic Aperture Radar (DInSAR) and nearby Global Navigational Satellite System (GNSS) stations, we invert for the geometry and slip of the causative fault. We find that both a steep SW‐dipping fault (dip 71°) and a shallow NE‐dipping fault (dip 15°) can fit the data equally well. However, the slip on the SW‐dipping fault occurs at depths 11–23 km, similar to the depths of the mainshock and aftershock seismicity, and thus, we prefer that model. The location of our preferred fault plane correlates with the mapped SW‐dipping backthrust, the Vore fault. The fault rupture did not reach the surface, which implies that an updip stress propagation onto the unruptured shallow portion of the Vore fault and its secondary structures pose an increased seismic hazard for cities in Albania, including the capital, Tirana.

Rock mass properties and their suitability as a foundation for a rolled compacted concrete gravity dam: case study of Beni Haroun dam (Mila, NE Algeria)

Dams are generally designed and built to resist the most severe destabilizing conditions. Their failures have caused severe damages and loss of lives through history. The investigations carried out on failed dams have, in most cases, unveiled that foundation problems are usually the cause. These problems are very often related to the condition of discontinuities dissecting the rock foundations. Being weak, they are the preferred planes for deformation and rupture causing the collapse of the whole structure. This study deals with the rock mass properties and their suitability as rock foundation for Beni Haroun dam, the largest dam in Algeria. The dam is located in the north-eastern part of Algeria on Wadi El-Kebeir, approximately 40 km from its outfall in the Mediterranean Sea. The dam is a roller-compacted concrete type with a height of 120 m, a crest length of 710 m, and a water storage capacity of approximately 1 billion m3. The dam is founded on Ypresian limestone rock mass. The present study was carried out both in the field and in a laboratory. The field study included geological mapping of the engineering, an intensive discontinuity survey, and sampling. Laboratory tests were conducted to determine shear strength, uniaxial compressive strength, tensile strengths, and Young’s modulus of rock samples. The shear strength of discontinuity was evaluated according to the criterion developed by Barton and Choubey. The joint roughness coefficient was calculated through a statistical approach using the parameter Z2, and an empirical approach based on a visual comparison with standard profiles of the Barton–Choubey roughness. The quality of the rock mass was estimated using Rock Mass Rating (RMR) and Geological Strength Index (GSI) systems. The stability of the dam foundation was assessed using the DMR system and the Hoek and Brown failure criteria. The rock mass of the dam foundation is the Ypresian limestone formation and is of fair quality. This study has shown that this rock mass is adequate as foundation for Beni Haroun RCC dam.

SrCO3 Assisted Synthesis of Disk-Like Micron-Sized Monocrystalline LiNi0.5Co0.2Mn0.3O2 with Preferred (104) Plane and Its Enhanced Cycle Performance

Disk-like micron-sized monocrystalline LiNi0.5Co0.2Mn0.3O2 is synthesized by the co-precipitation method accompanied with calcination assisted by strontian carbonate without washing process or other complicated treatment. Powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy are used to characterize the obtained samples. Characterizations reveal that the addition of SrCO3 help to form monocrystalline LiNi0.5Co0.2Mn0.3O2 with preferred (104) plane, and the particle is disk-like and in micrometer size. Electrochemical test results indicate that the LiNi0.5Co0.2Mn0.3O2 exhibits significantly improved capacity retentions of 95.6% and 89.3% after 100 cycles at 1C, for the voltage ranges of 2.8−4.3 V and 2.8−4.5 V, respectively. The excellent cycle performance of the LiNi0.5Co0.2Mn0.3O2 is ascribed to the unique monocrystalline morphology, high stability of (104) plane and reduced irreversible phase transition.

Can the morphological attributes of greater palatine foramen have implications in maxillary nerve block? An analytical study using anatomical planes

IntroductionMost popular approach for maxillary nerve block is via greater palatine canal (GPC) which is often difficult to access due to anatomical variations of its entry point the greater palatine foramen (GPF) thus resulting in failure of nerve block. It was hypothesized that exploring morphology of GPF with a modified approach may be useful towards its localization in an accurate manner. Materials & methodsThe study was conducted on 35 dry adult human skulls with help of anatomical planes and quadrants on surface of hard palate on both sides of mid-sagittal plane (MSP). ResultsIt was observed that GPF was located predominantly in Md2 and M2 quadrants with an incidence of 88.83% and 88.84% on the left and right side of MSP respectively (when third maxillary molar is present) and in 100% cases on both sides of MSP (when third molar is absent). MSP was identified as preferred plane for GPC approach because of its proximity to upper incisors. Two rectangular areas were identified around point of intersection (Px) between P2 and P3 anatomical planes (5 mm anterior to Px, 2 mm posterior to Px and 2 mm on either side of Px) and posterior to point of intersection (Py) between P2 and P4 anatomical planes (5 mm posterior to Py and 2 mm on either side of Py) with high incidence of GPF when third molar is present or absent respectively. ConclusionThe observations from this study may reduce risk of error in localizing GPF during maxillary nerve block.

Comprehensive Engineering Geological Analysis on Large-Scale Anti-dip Slopes: A Case Study of Changshanhao Opencast Gold Mine in China

Flexural toppling failure of large-scale anti-dip slopes constitutes a significantly rare phenomenon. With regard to the large-scale anti-dip slope instability at the southwest stope of Changshanhao Opencast Gold mine, in this work, a field engineering geological survey on the Changshanhao open stope was conducted, to investigate the structural plane features of the corresponding slope rock mass. Moreover, an equatorial horizon projection and strike rose diagram were utilized to determine the preferred structural plane of the joint fissures; the exposed rock mass integrity zoning of slope and the rock sample property testing on the main lithological compositions in the stope were also established. Based on the results of previous field investigations and indoor rock mechanics experiments, along with the occurrence conditions of stratigraphic structures unmasked by existing engineering geology borehole data, geographical explorations and mining engineering, the failure mode of southwest stope slopes were also determined. Finally, several suggestions were provided on the reinforcement and treatment of dangerous slopes within the ultimate mining boundary, consequently laying a foundation for sustainable safe mining.

Effect of the Eu3+-Sn4+ substitution on the structural and optical properties of SnO2:Eu3+

SnO2 nanocrystals with an average partiaxsxddccle size around 50 nm were prepared by using hydrothermal method. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) data show that the doping of Eu3+ with concentrations ranging from 0 to 2 mol% resulted in a slight decrease of size from 50 to 35 nm. The High Resolution Transmittance Electron Microscopy (HRTEM) results of 1 mol% doping sample provide that the crystals size is around 38 nm and the interplanar spacing is 0.34 nm characterized for (110) planes of SnO2. Moreover, the peak shape and relative intensity of Eu3+ emission upon a direct and indirect excitation indicate the presence of two sites around Eu3+ ions, that are in the D2h sites of SnO2 and on the surface of nanocrystals. The Eu3+ ions located in different sites are selectivity excited. An optimizing of synthesis parameters can promote the incorporation of Eu3+ ions in SnO2 crystal lattice. Specially, the doping leads to the growth of crystallites along (101) preferred plane. The competition between red and orange emission as a function of Eu3+ contents was also considered. Under indirect excitation, the asymmetric ratio between 5D0-7F2 and 5D0-7F1 transitions of Eu3+ ions is unaltered at 0.3 in the range of Eu concentrations from 0.5 to 2 mol% achieved for the first time. PL spectra and decay measurements give evidence about the strong energy transfer between SnO2 and Eu3+ ions.

Synthesis and electrochromic property improvement of NiO films for device applications

We have prepared the NiO films using electron-beam evaporation with a specially designed target. The films were characterized by X-ray diffraction, scanning electron microscopy, UV-visible spectrophotometry and cyclic voltammetry. The structure of NiOx films with (111) preferred plane orientation is good for electrochromic properties. The (111) orientated film shows tetrahedron-island structures. The best of the grown film shows high transmittance modulation at the wavelength of 550 nm with good durability and electrochromic properties after 800 cycles. The coloration efficiency of the best film is about 34 C/cm2. The electrochromic properties of the developed NiO films are discussed and compared for possible device applications.

Orientation prediction of fracture initiation from perforated horizontal wells: Application in shale reservoirs

For maximum productivity enhancement when targeting low permeability formations, horizontal wells must be made to induce multiple transverse fractures. An orientation criterion for fracture initiation is developed using analytically-derived approximations for the longitudinal and transverse fracturing stresses for perforated wellbores from the literature. The validity of the criterion is assessed numerically and is found to overestimate transverse fracture initiation, which occurs under a narrow range of conditions; pertaining to low breakdown pressure and low formation tensile strength.A three-dimensional numerical model shows that contrary to existing approximations, the transverse fracturing stress from perforated horizontal wells becomes more compressive as wellbore pressure increases. This shrinks the “breakdown pressure window,” which is the range of wellbore pressures over which transverse fracture initiation takes place. This creates a second constraint for transverse fracture initiation, which is the "critical tensile strength" value. This determines the maximum formation tensile strength at which transverse fracture initiation is possible for a given in-situ stress state and perforation direction.Sensitivity analyses are performed based on data from seven unconventional shale reservoirs (Barnett, Bakken, Fayetteville, Haynesville, Niobrara, Marcellus and Vaca Muerta) for horizontal wells drilled parallel to Shmin. The frequent longitudinal fracture initiation occurrence indicated suggests fracture reorientation in the near-wellbore region to be a common event, through which the propagating fractures become aligned with the preferred fracture plane (perpendicular to the least compressive principal stress). This induces near-wellbore fluid tortuosity, which in turn can lead to completions and production-related problems, such as early screenouts and post-stimulation well underperformance.

A refined slip distribution of the 2013 Mw 6.7 Lushan, China earthquake constrained by GPS and levelling data

SUMMARYThe 2013 Lushan Mw 6.7 earthquake is the largest blind thrust event ever occurred on the southern segment of the Longmen Shan fault system. It has attracted extensive attention since it occurred 5 yr later following the 2008 Mw 7.8 Wenchuan destructive earthquake in this region. However, its slip distribution is still on debate due to the complex tectonic settings and limited near-field observations. In this study, we added some near-field GPS data, together with previously published GPS data and levelling data, and take consideration of possible coseismic and post-seismic effects caused by the 2008 Wenchuan earthquake, to construct a more accurate horizontal and vertical coseismic surface displacement field associated with the 2013 Lushan earthquake with a better spatial coverage. Then we invert for a refined slip distribution based on a flat-ramp-flat fault suggested by the relocated aftershock sequence and seismic imaging. Our preferred fault plane is striking southwest with 211° and dipping at varying angles of 4°, 35° and 12° separately for such a flat-ramp-flat geometry. The main rupture is roughly characterized by two asperities, including a round disk on the ramp with larger slips and an adjoining oval asperity on the shallow flat with smaller slips. The maximum slip is 1.2 m at 14.3 km focal depth, located at ∼20 km to the northwest of the GCMT epicentre. The released geodetic moment is 1.50 $\ \times $ 1019 Nm, equivalent to a Mw 6.7 earthquake. The slips on the fault plane clearly illustrate that this event is dominated by the thrusting and minor striking, which is consistent with its tectonic settings. Furthermore, if we assume the 2013 Mw 6.7 Lushan event to be the characteristic earthquake on the southern section of the Longmen Shan thrust zone, the accumulated strain should not be fully released by this strong event, and a potential seismic risk still exists in this region.

Source characterizations of the New Cairo earthquake, Egypt

The New Cairo region was hit by a moderate size earthquake (Mw = 4.18) on midday Monday, 31st December 2018 that was felt throughout the greater Cairo region without any reported damage. The source mechanism solution and moment tensor inversion exhibit a normal fault with a minor strike-slip component. The NW-fault plane is the preferred rupture plane consistent with the geological and tectonic settings of the region. The dynamic source parameters have calculated, assuming a simplified circular source model, by using displacement spectra. The obtained source parameters are included average seismic moment is 2.41E+15 N-m, rupture radius of 0.46 Km, stress drop is 10.9 MPa, relative displacement is 0.012 cm, and energy releases are 1.2E+18 Erg. According to “Scholz” (1990), the studied earthquake might be considered as an intraplate type-(II) earthquake that related to plate boundaries. In the present study, the thermal infrared data is used to derive Land Surface Temperature (LST) as a precursory analysis for this earthquake. The results indicated that there was a correlation between LST with precursor seismic activity before the time of the New Cairo earthquake occurrence.

Revealing the erosion-corrosion performance of sphere-shaped morphology of nickel matrix nanocomposite strengthened with reduced graphene oxide nanoplatelets

Exceptional mechanical and better surface properties of metals are highly desirable for current pioneering applications. Recently, the electrochemical deposition is regarded as one of the appropriate methods to produce nanocomposite coatings with higher mechanical and excellent corrosion resistance properties. In this work, nickel-metal matrix nanocomposite coating reinforced with reduced graphene oxide (rGO) platelets has been fabricated with an electrochemical deposition technique to investigate the potential to improve the surface properties. The findings of this study demonstrate the impelling effect of rGO nanoplatelets on the mechanical and electrochemical properties of the produced nanocomposite coating. The sphere-like morphology, higher micro-hardness (504 HV) and enhanced erosion-corrosion resistance (4.07 Rct/kΩcm2) compared with a pure nickel coating (240 HV, 1.75 Rct/kΩcm2, respectively) are observed for nickel-rGO nanocomposite coating. Moreover, the thickness of the coating is significantly increased with the introduction of rGO nanoplatelets. The remarkable microstructure refinement is obtained which is supported by the intensity reduction of preferred planes of the Ni matrix. Furthermore, the grain sizes are decreased from 35.82 nm to 22.79 nm for rGO reinforced nanocomposite coating. The average roughness (Ra) (Ra: 41.7 to Ra: 342) and long-time erosion-corrosion performance are improved due to the strengthening effect of rGO nanosheets reinforcement.

Characterization of thin film of CuO nanorods grown with a chemical deposition method: a study of significance of deposition time

In this study, vertically aligned copper oxide (CuO) nanorods were grown on indium tin oxide substrate using chemical bath deposition as a facile and economical method. The effect of deposition times on the morphological, structural, optical, and electrical properties of CuO nanorods was investigated. X-ray diffraction analysis confirmed one-dimensional growth of CuO nanorods along the preferred plane of (002). Field emission scanning electron microscopy analysis revealed the growth of vertically aligned nanorods for all deposition times. It was observed that the length of nanorods and UV–vis absorption of the CuO thin films was increased with duration of growth. Current-voltage response of the samples was investigated and the results showed a linear behavior for all samples. Electrical resistance of nanorods was also measured. The results showed that the electric resistance decreases with increasing the growth time up to 90 min and it increases afterwards.

Analysis and characterisation of polycrystalline ZnS nanostructure

Zinc Sulfide (ZnS) thin films were deposited on glass substrates at the pressure of 10-6 mbar by thermal resistor evaporation technique. The effects of annealing on the structural and optical properties of ZnS films were studied. Polycrystalline ZnS films have been analyzed by X-ray diffraction. Only hexagonal phase with the preferred (111) plane was found in ZnS films. Optical characteristics were studied as a function of annealing temperature and film thickness in air. The results show that the energy band gap was found to be about 3.5 eV. It was observed that the energy gap decreases with the increase in the film thickness and increases with the increase in the annealing temperature.

A structure and activity relationship for single-walled carbon nanotube growth confirmed by in situ observations and modeling.

The structure and phase transformation of a cobalt (Co) catalyst, during single walled carbon nanotube (SWCNT) growth, is elucidated for inactive, active and deactivated nanoparticles by in situ imaging using an environmental transmission electron microscope. During nanotube growth, the structure was analyzed using Miller indices to determine the types of planes that favor anchoring or liftoff of nanotubes from the Co catalyst. Density functional theory was further applied to model the catalyst interactions to compare the work of adhesion of the catalyst's faceted planes to understand the interactions of different Miller planes with the graphene structure. Through in-depth studies of multiple distinct Co nanoparticles, we established a dominant nanoparticle phase for SWCNT growth. In addition, we identified the preferred lattice planes and a threshold for work of adhesion to allow the anchoring and liftoff of SWCNTs.

Synthesis of Nanosized Titanium Dioxide (Tio2) by Sol-Gel Method

Nanosized Titanium dioxide (TiO2 ) was synthesized by sol-gel method and it was characterized by XRD, EDX, SEM, FTIR and DRS-UV-Visible spectroscopy to study the structural, morphological and optical properties of the prepared nano TiO2 . The presence of elements Ti (54.5%) and O (40.5%) are confirmed by Energy dispersive X-ray spectroscopy (EDX) analysis. The X-ray diffraction analysis (XRD) confirms the presence of Nano crystalline anatase phase TiO2 . The average crystallite size calculated from the XRD data using Debye-Sherrer equation was ~15 nm and the preferred orientation plane was (101). The DRS-UV-Visible spectra analysis shows that the band gap energy (Eg) value calculated for the nano TiO2 was 3.18 eV. The surface morphology of the nanoTiO2 was studied by scanning electron microscopy (SEM) analysis, it shows that the uniform anatase phase TiO2 with nano plate like structure.

Effect of various technological parameters on particle morphology and uniformity of α-Ni(OH)2 synthesized via surfactant-free hydrothermal route

Hierarchical microspheres of α-Ni(OH)2, uniform in size and shape, have been synthesized through a facile surfactant-free hydrothermal route. Experimental parameters such as reaction time, temperature and reactant concentration were systematically optimized to produce monodispersed particles. SEM analysis confirmed that the particles synthesized from a recipe containing 2.65 × 10−2 mol. L−1 nickel chloride and 5.6 × 10−1 mol. L−1 urea aged at 85 °C for 2 hours were uniform in size and morphology. HR-TEM results showed that the hierarchical microspheres are made up of thin sheet-like units. The crystal structure of the α-Ni(OH)2 microspheres was investigated by XRD which showed (003) as the preferred orientation plane having 7.369 Å interplanar spacing and crystallite size of 21 nm. The intercalation of CO3 −2 and OCN− species was revealed by FT-IR spectroscopy. The average activation energy (41.23 KJ mol−1) for thermal-induced transformation reaction was determined based on the TG/DTA data recorded at three heating rates. The present green and facile route could be extended to synthesize monodispersed systems of other metal compounds.

Effect of Deposition Time on Structural, Morphological and Optical Properties of PVA Capped SnS Films Grown by CBD Process

In this study, the effect of deposition time on physical properties of tin monosulphide films capped by polyvinyl alcohol was investigated. Chemical bath deposition technique was used to deposit Polyvinyl alcohol capped SnS films on cleaned glass substrates and the deposition was carried out at four different times varying from 45 to 90 min. The X-ray diffraction study revealed that the deposited layers were polycrystalline in nature with (040) as the preferred plane. Single phase SnS was observed in the layers grown at a deposition time of 90 min while the other layers had secondary phases of Sn and S. The XRD data was also used to determine various parameters such as crystallite size, dislocation density, lattice strain, stacking faults and inter planar spacing. Raman measurements exhibited same structural phases, consistent with the XRD observations. The surface morphology of the layers was initially uneven and become uniform at 90 min deposition time. Fourier transform infrared spectra, confirmed the presence of SnS and PVA in the films. Optical studies revealed high optical absorption coefficient for all the films with a shift in optical band gap value compared with the bulk value.

Influence of gamma radiation on the optical, morphological, structural and electrical properties of electrodeposited lead selenide nanowires

The influence of gamma radiation exposure is studied on the optical, morphology, structural and electrical properties of PbSe nanowires with 100 nm diameter. The PbSe nanowires are synthesized by template-based electrodeposition technique. Samples are exposed using Co60 gamma source at different doses. Gamma radiation is electromagnetic radiation with high energy, frequency and penetrating power. Gamma radiations at precise doses can tune the physical properties of PbSe nanowires as infrared detectors for various applications. The optical study was carried out using UV–Vis NIR spectroscopy in reflectance mode. Further, the optical parameters such as bandgap, refractive index, static and high-frequency dielectric constant were calculated for pristine and gamma radiation exposed PbSe nanowires. The bandgap as calculated from Kubelka-Munk function decreased from 0.74 eV to 0.60 eV with an increase in dose from pristine to 200 kGy. The morphology of the nanowires was recorded using scanning electron microscopy. The nanowires obtained are cylindrical in shape and uniform throughout the length. The detailed analysis of the structural properties of PbSe nanowires is done using Scherrer and W–H methods. The preferred orientation of planes was determined by texture coefficient analysis. Strain, stress and energy density is calculated for the most preferred plane as obtained in texture coefficient (TC) analysis. The I–V characteristics is calculated before and after gamma exposure. In Raman spectra, the evolution of 2LO vibrational mode was observed with an increase in gamma radiation dose. The I–V characteristics represent space-charge limited conduction (SCLC) behaviour and an increase in current with increase in gamma dose for PbSe nanowires which makes it important for various potential applications in optoelectronic devices.

Morphological analysis of mandibular foramen through anatomical planes: implications for inferior alveolar nerve block

Error in localization of mandibular foramen is attributed to a high failure rate of inferior alveolar nerve block in clinical dentistry. We hypothesized that a remodelled approach towards exploring the morphology of mandibular foramen would be useful. In the present study, the location of the mandibular foramen was analysed with respect to the anatomical planes across the ramus of the mandible and also with respect to the quadrants on the medial surface of ramus of mandible. The study was conducted on 50 dry human mandibles of unknown age and sex. The anatomical planes were defined and drawn on the mandibles. Measurements were made with digital Vernier callipers and findings were noted. It was observed that the most consistent position of the mandibular foramen was along the vertical plane, however, the foramen was most likely to be localized along the oblique plane. Morphological analysis of the foramen with respect to the anatomical planes as well as the quadrants on the medial surface of ramus led to the analysis that occlusion plane should be the preferred plane of approach. Moreover, a rectangular area on the medial surface of the ramus was identified posterior to the mid-point of occlusion plane (8mm above mid-point, 6mm below mid-point and 6mm behind mid-point) where the incidence of location of the foramen was significantly high. The findings of this study may potentially reduce the failure rate of inferior alveolar nerve block and clinical complications thereof.