Response Analysis of Field-Scale Fully Grouted Standard Cable Bolts Using a Coupled ANN–FDM Approach

This paper presents a coupled approach using an artificial neural network (ANN) and the finite difference method (FDM) that has been developed to predict the distribution of axial load along fully grouted standard cable bolts in the field using laboratory pullout test data. A back-propagation training algorithm was used in ANN to determine axial loads in the cables tested in the laboratory. The ANN component of the computational model was trained using two different types of data sets. At first, the ANN was trained to predict the axial loads in a series of short cables grouted with Portland cement at a specific water-to-cement ratio and subjected to different radial confining stiffness values. Next, the ANN model was trained for an expanded case to include the influence of lateral confining stress on the distribution of axial load in the cable reinforcement. Finally, the ANN model was implemented into a widely used, FDM-based geotechnical software (FLAC). The accuracy of the ANN–FDM model is demonstrated in this paper against measured data from laboratory and field tests. The analysis approach introduced in this study is a valuable computational tool that can be used to determine the axial load distribution in long standard cable bolts, which are commonly installed to stabilize rock masses in various geotechnical, transportation, and mining applications.     

Comparison of MBE Growth of InSb on Si (001) and GaAs (001)

We describe the epitaxial growth of InSb films on both Si (001) and GaAs (100) substrates using molecular-beam epitaxy and discuss the structural and electrical properties of the resulting films. The complete 2 μm InSb films on GaAs (001) were grown at temperatures between 340°C and 420°C and with an Sb/In flux ratio of approximately 5 and a growth rate of 0.2 nm/s. The films were characterized in terms of background electron concentration, mobility, and x-ray rocking curve width. Our best results were for a growth temperature of 350°C, resulting in room-temperature mobility of 41,000 cm²/V s.  For the growth of InSb on Si, vicinal Si(001) substrates offcut by 4° toward (110) were used. We investigated growth temperatures between 340°C and 430°C for growth on Si(001). In contrast to growth on GaAs, the best results were achieved at the high end of the range of T _S =  C, resulting in a mobility of 26,100 cm²/V s for a 2 μm film. We also studied the growth and properties of InSb:Mn films on GaAs with Mn content below 1%. Our results showed the presence of ferromagnetic ordering in the samples, opening a new direction in the diluted magnetic semiconductors.     

Approximation and inapproximability results for maximum clique of disc graphs in high dimensions

We prove algorithmic and hardness results for the problem of finding the largest set of a fixed diameter in the Euclidean space. In particular, we prove that if A^∗ is the largest subset of diameter r of n points in the Euclidean space, then for every ε>0 there exists a polynomial time algorithm that outputs a set B of size at least |A^∗| and of diameter at most . On the hardness side, roughly speaking, we show that unless P=NP for every ε>0 it is not possible to guarantee the diameter for B even if the algorithm is allowed to output a set of size .     

CFD simulation and optimization of ICEs exhaust heat recovery using different coolants and fin dimensions in heat exchanger

In this paper, finned type heat exchangers with different fin dimensions in the exhaust of a gasoline engine are modeled numerically for improving the exhaust energy recovery. RNG k-ε viscous model is used and the results are compared with available experimental data presented by Lee and Bae (Int J Therm Sci 47:468–478, 2008) where a good agreement is observed. Also, the effect of fin numbers, fin length and three water-based nanofluid coolants (TiO₂, Fe₂O₃ and CuO) on the heat recovery efficiency are investigated in different engine loads. As a main outcome, results show that increasing the fin numbers and using TiO₂-water as cold fluid are the most effective methods for heat recover. Furthermore, an optimization analysis is performed to find the best fins dimensions using response surface methodology.     

Coupled vibration of a cantilever micro-beam submerged in a bounded incompressible fluid domain

This paper investigates the free vibrations of a cantilever micro-beam submerged in a bounded frictionless and incompressible fluid cavity. Based on the Fourier–Bessel series expansion and using linear potential theory, an analytical method is proposed to analyze the eigenvalue problem, where the fluid effect emerges as an added mass. Wet beam vibration mode shapes together with the sloshing modes of the oscillating liquid are depicted. Moreover, effects of geometrical configuration and fluid density on the natural frequencies of the coupled system are evaluated. Results show that in spite of the high added mass values related to lower modes, presence of the fluid changes the higher modes more effectively.     

UPLC and HPLC of caffeoyl esters in wild and cultivated Arctium lappa L.

Analytical methods including ultra-performance liquid chromatography (UPLC) and high-performance liquid chromatography (HPLC) with photodiode array (PDA) detector were developed for the analysis of caffeoylquinic acid derivatives in seeds, leaves and roots of Arctium lappa L. Separation was performed on C₁₈ column utilising 5% (v/v) acetic acid in water and acetonitrile at 330 nm. Both methodologies were validated in terms of linearity, precision, and recovery. The results showed that the major advantages of UPLC, over HPLC were the fast analysis, narrow peaks, high sensitivity, and reduction of solvent consumption. Subsequently the methods were applied for the identification and quantification of chlorogenic acid (5-CQA) and 1,5-dicaffeoylquinic acid (1,5-DCQA) as main compounds in samples. The total phenolic content of samples ranged from 3.93 to 14.13 g of 5-CQA equivalent/100 g dry weight (DW). There was a significant variability from 89 to 571 mg/100 g for 5-CQA and 48 to 486 mg/100 g for 1,5-DCQA in dry material.     

On the application of electrochemical machining for inner surface polishing of gun barrel chamber

Inner surface polishing of complex parts with high precision can be easily done by electrochemical polishing method. In this research, cartridge house inner surface electrochemical polishing of a gun pipe, with numerous serial surface angles, is analyzed. So that, according to the various set ups, the optimized polishing parameters are obtained. The comparison between electrochemical polishing and conventional methods from this point of view, shows good advantages of this method, so that, the machining time is more than 30 times less and with very high-surface quality. Besides, the dimensional accuracy of the workpiece repeatability process in this polishing method is noticeable.     

Selecting human machine interface package in integrating a process automation system

In this paper we propose a framework for evaluating and selecting human machine interface (HMI) packages in integrating a process automation system. HMIs are among main subsystems of many integrated process automation systems. The main objective of this paper is to propose a selection process so that the integrated system could better satisfy strategic goals of the system users. In this paper we assume that strategic goals are expressed in terms of concepts like production flexibility, production reliability, product quality, operation cost, production time and the like.