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991.
Mohammad‐Mahdi Sharif Mohammad Nahangi Carl Haas Jeffrey West 《Computer-Aided Civil and Infrastructure Engineering》2017,32(11):893-908
Finding construction components in cluttered point clouds is a critical pre‐processing task that requires intensive and manual operations. Accurate isolation of an object from point clouds is a key for further processing steps such as positive identification, scan‐to‐building information modeling (BIM), and robotic manipulation. Manual isolaton is tedious, time consuming, and disconnected from the automated tasks involved in the process. This article adapts and examines a method for finding objects within 3D point clouds robustly, quickly, and automatically. A local feature on a pair of points is employed for representing 3D shapes. The method has three steps: (1) offline model library generation, (2) online searching and matching, and (3) match refinement and isolation. Experimental tests are carried out for finding industrial (curvilinear) and structural (rectilinear) elements. The method is verified under various circumstances in order to measure its performance toward addressing the major challenges involved in 3D object finding. Results show that the method is sufficiently quick and robust to be integrated with automated process control frameworks. 相似文献
992.
A new model based on finite fracture mechanics is proposed to predict the open-hole tensile strength of composite laminates. Failure is predicted when both stress-based and energy-based criteria are satisfied. The material properties required by the model are the ply elastic properties, and the laminate unnotched strength and fracture toughness. No empirical adjusting parameters are required. Using experimental data obtained in quasi-isotropic carbon–epoxy laminates it is concluded that the model predictions are very accurate, resulting in improvements over the traditional strength prediction methods. It also is shown that the proposed finite fracture mechanics model can be used to predict the brittleness of different combinations of materials and geometries. 相似文献
993.
Cyanide is a highly poisonous and hazardous substance which may release into the environment from natural sources or industrial effluent; therefore, cyanide detection is a fundamental step to prevent environmental pollution and secure health and safety. In this study, we prepared a sensitive amperometric inhibition biosensor for cyanide detection by immobilization of horseradish peroxidase (HRP) enzyme and reduced graphene oxide (rGO) on the surface of glassy carbon electrode (GCE). To do so, we performed the amperometric measurement by modified GCE to test its efficiency in detecting cyanide. The optimum conditions of pH equal to 7.5, −100 mV applied potential, 0.7 μM mediator concentration, and 0.5 mM substrate concentration were found. Then, experiments were performed at different boundary conditions in a range of 0.1 to 10 μM cyanide concentration at optimal conditions and a low detection limit of 0.01 μM was obtained. Also, the possible mechanism of inhibition was analyzed based on the Michalis–Menten equation and non-competitive inhibition was observed. Due to high sensitivity, low detection limit, and low cost, this biosensor is proposed as a useful method for cyanide determination in real samples. 相似文献
994.
Ghasem Bahlakeh Manouchehr Nikazar Mohammad-Javad Hafezi Erfan Dashtimoghadam Mohammad Mahdi Hasani-Sadrabadi 《International Journal of Hydrogen Energy》2012
Molecular dynamics (MD) simulation technique was employed to investigate the effect of degree of sulfonation (DS) on structural and dynamical characteristics of sulfonated poly (ether ether ketone) (SPEEK) membranes at different temperatures. MD Simulations were performed for the cell containing SPEEK chains, hydronium ions and water molecules under NVT and NPT conditions. By evaluating the pair correlation functions, it was observed that with increasing the DS of SPEEK, the distance between sulfur atoms increases, more water molecules solvate the sulfur atoms and hydronium ions, the average sulfur–hydronium ion separation distance increases and larger water clusters are formed. It was also found that with increasing DS and temperature, the diffusion coefficient and conductivity of hydronium ions enhance. It was also understood, the simulated ionic conductivities qualitatively follow the experimental data. 相似文献
995.
Mojtaba Sepehrnia Ghanbarali Sheikhzadeh Golnoush Abaei Mahdi Motamedian 《亚洲传热研究》2019,48(4):1151-1179
In this study, the turbulent natural convection of Ag‐water nanofluid in a tall, inclined enclosure has been investigated. The main objective of this study is finding the optimized angle of the enclosure with operational boundary condition in cooling from ceiling utilizing the computational fluid dynamics‐artificial neural network (CFD‐ANN) hybrid method, which has not been noticed in previous studies. To achieve this, we proposed two approaches. First, the simulations have been done with a deviation angle of 0 to 90° by using water and Ag‐water nanofluid. And second, a new prediction approach is proposed based on radial basis function artificial neural networks (RBF‐ANN) to predict the mean Nusselt number and entropy generation with the variation of Rayleigh numbers, deviation angles, and volume fractions as inputs. The results from the first approach indicate that the Rayleigh number has a considerable function in the determination of optimized angle. The results from the second approach, which used the first approach simulation results as training data set, could predict the mean Nusselt number and entropy generation with 1.4577e?022 and 1.552e?015 mean square error, respectively. Moreover, a new set of data for Rayleigh numbers, deviation angles, and volume fractions were used to test the performance of the prediction model, which shows promising and superior prospects for RBF‐ANN. 相似文献
996.
Nemati Jamshid Toosian Meysam Banisdar Seyed Shahin Ahmadpour Seyed Mahdi 《Journal of Mechanical Science and Technology》2019,33(8):3905-3911
Journal of Mechanical Science and Technology - This research investigated the mechanical properties of aluminum-based nanocomposite. The spark plasma sintering method was adopted to fabricate the... 相似文献
997.
Mehran Rezaei Seyed Mahdi Alavi Saeed Sahebdelfar Liu Xinmei Zi-Feng Yan 《Journal of Materials Science》2007,42(17):7086-7092
Mesoporous nanocrystalline zirconia with high surface area and pure tetragonal crystallite phase has been prepared by bifunctional
ethylene diamine as both precipitating agent for ZrO(NO3)2 to ZrO(OH)2 and colloidal protecting agent for the ZrO(OH)2 nanoparticles. The effect of refluxing time and temperature on the structural properties of the zirconia were investigated.
The obtained results showed that the increasing in refluxing time and temperature improved the thermal stability and increased
the tetragonal content of the zirconia. The results also showed that the addition of Pluronic P123 block copolymer surfactant
acted as a cosurfactant and increased the specific surface area of the zirconia. 相似文献
998.
This paper examines the effects of composite constituents and geometry on the energy absorption capability of composite hemispherical shells. To examine the effects of matrix types on their energy absorption capability, glass fibre/epoxy and glass fibre/polyester hemispherical shells were fabricated. While glass fibre/epoxy and carbon fibre/epoxy hemispherical shells were fabricated to investigate the effect of fibre reinforcements. Effect of aspect ratio (R/t) was also examined and the results were presented. The results obtained showed that the energy absorption capability of the hemispherical shells significantly affected by the composite constituents as well as R/t ratio. 相似文献
999.
Saman Rahnamaeiyan Mahdi Nasiri Amin Alborzi S. Mahdi Tabatabaei 《Journal of Materials Science: Materials in Electronics》2016,27(2):1113-1117
Zinc tungstate nanoparticles were synthesized via a sonochemical method based on the reaction between zinc (II) nitrate hexahydrate and sodium tungstate dihydrate in water. The structural, morphological and optical properties of as-obtained products were characterized by techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis, and ultraviolet–visible spectroscopy. The samples indicated a ferromagnetic behavior, as evidenced by using vibrating sample magnetometer at room temperature. To evaluate the catalytic properties of nanocrystalline zinc tungstate, the photocatalytic degradation of methyl orange under ultraviolet light irradiation was carried out. 相似文献
1000.
Behzad Karimi Amir Masoud Arabi Mahdi Shafiee Afarani 《Journal of Materials Science: Materials in Electronics》2017,28(2):1247-1252
In this research, nanocomposites containing carbon nanotube (CNT)-cadmium selenide (CdSe) quantum dots (QDs) were synthesized and deposited using electrophoretic deposition technique for optical sensors and displays. The composite was first synthesized using silane grafted cadmium selenide and different concentrations of carbon nanotubes, and then deposited on the aluminum electrodes via electrophoresis method. Fourier transformation infrared confirmed the formation of CNT–CdSe nanocomposites. Microstructural investigations using scanning and transmission electron microscopy also showed the presence of the QDs on the surface of carbon nanotubes (CNTs), enhancing their surface roughness. Increasing the applied voltage from 120 to 240 V resulted in the variation of deposition yield in the range of 0.0005–0.0035 g.cm?2. The deposition yield was first increased and then decreased in all the samples. Photoluminescence studies revealed that the deposited composite has a distinct emission peak in the range of 485–495 nm (green region) under 360 nm illumination depending on the concentration of CNTs. It can be concluded that the deposited composite may be used in field emission displays due to its high efficiency emission in the presence of CNTs. 相似文献