Surface plasmonic effect of nanoparticle-like silver nanostructure on the high responsivity of visible/infrared silver-based heterojunction photodetector

The fabrication of a silver (Ag) based photodetector on a silicon dioxide/p-silicon (SiO₂/p-Si) substrate using direct current (DC) magnetron sputtering is demonstrated. The proposed method deposits a nanoparticle-like Ag thin film that favours the photoconduction mechanism under light illumination at 468?nm and laser illumination at 660 and 980?nm. The thin film is characterized using scanning electron microscope (SEM), energy dispersive x-ray (EDX), x-ray diffraction (XRD), Raman scattering, photoluminescence (PL) and ultraviolet–visible (UV–VIS) analysis. Current–voltage (I–V) analysis and the calculated rectifying ratio (RR) suggests the establishment of good Schottky contacts for incident light/laser at 468, 660 and 980?nm, with good responsivity towards light and laser illumination in the forward and reverse DC bias regions. The responsivity increases as the wavelength decreases from 980?nm → 660?nm → 468?nm, with the highest responsivity of 213.7?mAW^?1 at 468?nm indicating better photoconduction at low light powers.     

Evidence for stable stoichiometric Ti2C at the interface in TiC particulate reinforced Ti alloy composites

Ti–6%Al–4%V composites containing 20 vol.% TiC particles were sintered at temperatures between 1273 and 1773 K for holding times of up to 20 h. Neutron diffraction and low voltage field emission gun scanning electron microscopy were used to investigate the development of the interfacial reaction region between the reinforcement and matrix. It has been observed that there is an interaction zone surrounding each particle caused by the diffusion of carbon from the reinforcement to the titanium alloy matrix. The extent of this reaction increases with increasing processing temperature and holding time. The single phase formed at the interfacial boundary between the particles and the matrix was determined from lattice parameter measurements to be stoichiometric Ti₂C. The significance of these findings are discussed in terms of previous work on interfacial characterization of TiC particulate reinforced Ti–6%Al–4%V composites.     

The Java Management Extensions (JMX): Is Your Cluster Ready for Evolution?

The arrival of commodity hardware configurations with performance rivaling that offered by RISC workstations is resulting in important advances in the state of the art of building and running very large scalable clusters at “mass market” pricing levels. However, cluster middleware layers are still considered as static infrastructures which are not ready for evolution. In this paper, we claim that middleware layers based on both agent and Java technologies offer new opportunities to support clusters where services can be dynamically added, removed, and reconfigured. To support this claim, we present the Java management extensions, a new Java agent-based technology, and its application to implement two disjoint cluster management middleware services (a remote reboot service and a distributed infrastructure for collecting Log events) which share a unique agent-based infrastructure.     

Removal of carbonyl sulfide from a liquid hydrocarbon with activated alumina

The removal of carbonyl sulfide from hydrocarbons to vanishing levels is an industrially important problem. Activated alumina of a special grade was used to successfully remove dissolved carbonyl sulfide by chemisorption from n-heptane as a model substance. The rate of removal was found to be controlled by surface reaction.     

Frequency switching multiwavelength Brillouin Raman fibre laser based on feedback power adjustment technique

A simple switchable multiwavelength Brillouin–Raman fibre laser (BRFL) was demonstrated. The laser was arranged in a half-open cavity configuration including a physical mirror device with an adjustable reflectivity at one side of the laser cavity. The impact of the feedback power adjustment on frequency switching was carried out by comparing the peak power difference between odd- and even-order Stokes lines. Up to 468 flat-amplitude lines with a 10?GHz frequency spacing and average optical signal to noise ratio (OSNR) of 33 dB were observed with mirror reflectivity values of ～15% up to 60% at a 1534?nm Brillouin pump power of 7?dBm and 0.9?W Raman pump power of 0.9?W. – Under the same pumping conditions, setting the mirror reflectivity at its OFF state (where reflectivity is nearly 0%) allows for up to 242 lines with 20?GHz spacing to be realized, with ONSR values of ～35?dB.     

Novel Surface Topography and Microhardness Characterization of Laser Clad Layer on TC4 Titanium Alloy Using Laser-Induced Breakdown Spectroscopy and Machine Learning

Metallurgical and Materials Transactions A - This study was performed to characterize surface topography and microhardness of 40 wt pct NiCrBSiC-60 wt pct WC hard coating on TC4 titanium after...     

Application of general regression neural network (GRNN) for indirect measuring pressure loss of Herschel–Bulkley drilling fluids in oil drilling

Experimental measurements of the pressure losses in a well annulus are costly and time consuming. Pressure loss calculations in annulus is generally conducted based on an extension of empirical correlations developed for Newtonian fluids and extending pipe flow correlations. However, correct estimation of pressure loss of non-Newtonian fluids in oil well drilling operations is very important for optimum design of piping system and minimizing the power consumption. In this paper, a general regression neural network (GRNN) was applied to predict the pressure loss of Herschel–Bulkley drilling fluids in concentric and eccentric annulus. Experimental data from literature were used to train the GRNN for estimating pressure losses in annulus. The predicted values using GRNN closely followed the experimental ones with an average relative absolute error less than 6.24%, and correlation coefficient (R) of 0.99 for pressure loss estimation.     

Implementation of ANN-based Selective Harmonic Elimination PWM using Hybrid Genetic Algorithm-based optimization

A PWM technique with Selective Harmonic Elimination (SHE) is used to control fundamental harmonic and eliminate harmonics of chosen lower-order in voltage source inverters (VSI). Therefore, this PWM technique requires the determination of the optimum switching angles by solving the nonlinear equation set. The determined angles are recorded on a look-up table to generate PWM signals in real-time systems. The paper proposes two Artificial Neural Networks (ANN) based solution for determining angles and generating PWM signals. ANN generates optimum switching angels for all modulation index between 0 and 1.20 because of it has learning capability differently from the look-up table. Primarily, the optimum 11-switching angles for three-phase two-level inverter are determined by using offline Hybrid Genetic Algorithm (HGA). The first ANN was trained by the data obtained from HGA to calculate the switching angles without using a look-up table. Second ANN was trained by using these switching angles to generate PWM signals. The ANN-based SHEPWM was designed to obtain inverter output voltage which has a bipolar waveform with quarter-wave symmetry. The algorithm of ANN-based SHEPWM is performed by using TMS320F28335 Digital Signal Processor (DSP). The experimental results related to dc-link voltage, inverter output voltage and load current are measured for different M_a by using scope and power quality analyzer. The waveform of inverter output voltage are also analyzed with FFT for an induction motor load. The low-order harmonics are successfully eliminated by proposed ANN based SHEPWM.     

Application of two-output port fiber coupler as gasoline level sensor

Detection of gasoline level can be done in a safe and simple way using two output port multimode fiber coupler with a structure of 2 × 2 as a sensor. Two output ports (sensing port) are connected with two reflector displacement device (RDD) and functioned as two probes. These probes are placed on the wall of gasoline tank in a storied and work interchangeably or together depending on setting of these probes. Detection mechanism of the system is based on changes in intensity of reflected light from the reflector RDD that shifts due to changes in level of gasoline (hydrostatic pressure principle). Changes in intensity of light coming into the sensing port are then forwarded to the optical detector. Experiments performed by varying the location of the second probe as 45 cm, 50 cm, and 55 cm above the first probe to detect the level of gasoline in the process of filling and emptying the tank. Experimental results show the process of filling and emptying the tank have small differences of 6% with the dynamic range, the linear region, and resolution are 100 cm, 70 cm, and 0.4 cm respectively. Sensor sensitivity in filling and emptying process of the tank are 2.7 mV/cm and 2.8 mV/cm respectively. These results were the best performance of the sensor, which occurs when the level of the second probe was 55 cm above the first probe.     

3D measuring and segmentation method for hot heavy forging

Non-contact, three-dimensional (3D) measurements of hot heavy forgings (HHFs) are desirable for permitting real-time process control, whereas most current methods are usually inconvenient or invalid due to the difficulty in dealing with the hot heavy forgings. This paper presents a new measuring and combined segmentation approach that employs a two-dimensional (2D) laser radar with additional rotation driven by the servomotor that scans the forgings to acquire a massive 3D point cloud dataset. From this dataset, the desired forging part is roughly distinguished from the background based on the angle and distance continuity constraints, and then refined by the curvature-based border extraction method and further segmented by the hierarchical clustering analysis method. Finally, the feature points are extracted based on the normal vector variation and fitted to convey the 3D information. This novel method has been verified by experiments both in the laboratory and the forging workshop for hot heavy forging pieces, with a dimension error of less than 2%. These results indicate that the proposed approach is more practical and convenient than current methods for real-time, on-site measurements of HHFs.