Performance evaluation of a diesel engine fueled with methyl ester of castor seed oil

In this investigation, castor methyl ester (CME) was prepared by transesterification using potassium hydroxide (KOH) as catalyst and was used in four stroke, single cylinder variable compression ratio type diesel engine. Tests were carried out at a rated speed of 1500 rpm at different loads. Straight vegetable oils pose operational and durability problems when subjected to long term usages in diesel engines. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. The process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. The important properties of methyl ester of castor seed oil are compared with diesel fuel. The engine performance was analysed with different blends of biodiesel and was compared with mineral diesel. It was concluded that the lower blends of biodiesel increased the break thermal efficiency and reduced the fuel consumption. The exhaust gas temperature increased with increasing biodiesel concentration. The results proved that the use of biodiesel (produced from castor seed oil) in compression ignition engine is a viable alternative to diesel.     

Determination of hydrodynamic properties of bare gold and silver nanoparticles as a fluorescent probe using its surface-plasmon-induced photoluminescence by fluorescence correlation spectroscopy

Noble-metal nanoparticles labeled with fluorescent molecules are used in a variety of applications requiring the measurement of size and diffusion properties of single nanoprobes. We have successfully used intrinsic surface-plasmon-induced photoluminescence (SPPL) signatures of monodispersed bare gold and silver nanoparticles in water to detect and measure their precise diffusion coefficient, concentration and hydrodynamic radius by fluorescence correlation spectroscopy (FCS). Measurement of the effective hydrodynamic radius confirms particle size to be 80 ± 8 and 64 ± 14 nm for gold and silver, respectively, which is in excellent agreement with scanning electron microscopic measurements made on the same particles. Detection of bare gold and silver nanoparticles at the single-molecule level with moderately high value of "per particle brightness" (PPB) confirms those particles to be used as fluorescent probes in biological research and in different medical and biotechnology applications where fluorescence detection plays a vital role. Additionally, these results demonstrate an alternative method for measuring hydrodynamic properties, particularly the size-distribution of bare noble-metal nanoparticles in solution using data-fitting algorithm for FCS based on the maximum entropy method (MEMFCS).     

Small planar antenna array design using length and spacing through Matlab-HFSS interfacing

This study presents a novel method for reducing return loss and achieving lower side lobe levels in small planar antenna arrays (PAAs). Quantum particle swarm optimisation (QPSO) findings are utilised for antenna design modelling and performance assessment utilising the MATLAB-based moment's code approach and MATLAB-HFSS interface. The mutual coupling between antenna components is considered and computed using the method of moments (MoM). Changing the array elements' length and spacing will accomplish the abovementioned objectives. The Matlab-based moments code calculates the antenna components' length and spacing, and the antennas' length and spacing are used to produce the radiation pattern via the Matlab-HFSS interface. Four examples of small PAA designs are given to illustrate how well the applied methodology works. The method discussed in this paper is generic and can be employed in the future for different sizes of the array elements and the different antenna array structure designs.     

Femtosecond laser-tissue interactions: Retinal injury studies

We report the first study of laser-tissue interaction in the femtosecond time regime. Retinal damage thresholds and mechanisms produced by exposure to high-intensity femtosecond laser pulses were investigated in chinchilla grey rabbits. Exposures were performed using single laser pulses of 80 fs duration at 625 nm. ED50injury thresholds of 0.75 and 4.5 μJ were measured using fluorescein angiographic and ophthalmoscopic visibility criteria evaluating 204 laser exposures. Ultrastructural studies including light and electron microscopy were performed on selected lesions. Results suggest that the primary energy deposition in the retina occurs in melanin, However, in contrast to laser injuries produced by longer pulses, exposures of more than 100 × threshold in the50-100 muJ range did not produce significantly more severe lesions or hemorrhage. This suggests the presence of a nonlinear damage limiting mechanics in tissue exposed to femtosecond laser pulses.     

Predicting the quality of the final product using multivariate statistical techniques — A case study

This paper addresses the problem of predicting the performance of an acceptance sampling test. Algorithms using Chernoff faces, Discriminant analysis and Cluster analysis are proposed and tested on a real-life problem.     

Distributed computer system design: An interactive procedure

This paper presents an overview of an interactive system for the design of a distributed computer system. The system helps the designer in finding the optimal combination of processors of varying power to be located at various nodes of the system. It also helps in finding the optimal allocation of data files or databases. The system allows the designer to trade-off between the conflicting objectives: low investment and operating cost and high availability of data. Reasonable relative weights are assigned to each data file, and design objectives can be assigned priorities. A value added network such as TELENET is assumed for data communication. Also, multiple copies of the data file or database may exist in the system to achieve higher data availability and better response time.     

Thermal behavior of transparent poly(etheretherketone)(PEEK) film

The thermal behavior of poly(etheretherketone)(PEEK) film heated in an open differential scanning calorimetry (DSC) pan at 20°C/min is distorted by relaxation of the strained film. PEEK film in a closed pan or quenched PEEK in open or closed pans shows a glass-transition temperature (T_g) around 144°C, cold crystallization (～22 J/g) at 177°C, melt-temperature (T_m) peaking at 335–340°C, with an enthalpy of fusion of 32–34 J/g, and recrystallization on cooling at 285°C, with a crystallization exotherm of about 40 J/g. The enthalpy of fusion decreases with increasing heating rate from 2–100°C/min and approaches the enthalpy of cold crystallization. With increasing heating rate, further crystallization of PEEK during the DSC scan is suppressed. With increasing cooling rate, PEEK melt crystallizes at larger supercoolings to a lesser extent. Crystallization on cooling the melt was more complete than cold crystallization and annealing on heating.     

A comprehensive methodology for runout tolerance evaluation using discrete data

Runout is a composite tolerance that is usually specified to ensure proper alignment and rotational accuracy for axially symmetric features. The procedure for evaluation of runout defined in American Society of Mechanical Engineers (ASME) Y14.5M-1994 [1] and International Organization for Standardization (ISO)/TR 5460-1985(E) [3] depicts the rotation of a part around its datum axis while a dial gauge measures the variations in the feature’s surface. These standards do not address the evaluation of runout using modern measurement technologies using discrete point clouds that dominate the metrology industry. This research presents a comprehensive methodology for evaluating runout tolerance using discrete data that closely replicates the requirements specified by the ASME and ISO standards. This work builds upon previous work by the authors, reported in Turek et al. [9] and presents a comprehensive methodology for evaluating circular and total runout for flat, tapered, and cylindrical features using discrete data. The methodology was tested using simulated datasets and the analysis reaffirmed the results reported in Turek et al. [9] regarding the choice of minimum circumscribing cylinder as the preferred datum axis evaluation technique. Subsequently, the approach presented in this paper was applied to discrete data acquired from two manufactured parts. The results obtained were compared with traditional runout measurements acquired with a dial gauge. This comparison required the filtering of the discrete data to compensate for the finite radius of the dial gauge tip, and led to the development of a novel filtering technique to appropriately compare results. The results using the filtered data closely match the results obtained from the dial gauge, confirming the accuracy of the presented runout assessment algorithms. This work presents a first step in assessing runout using discrete data and justifies the use of modern metrology techniques in runout evaluation.     

Design and performance analysis of generalised integrator-based controller for grid connected PV system

This article discusses the design and control of a single-phase grid-connected photovoltaic (PV) system. A 5-kW PV system is designed and integrated at the DC link of an H-bridge voltage source converter (VSC). The control of the VSC and switching logic is modelled using a generalised integrator (GI). The use of GI or its variants such as second-order GI have recently evolved for synchronisation and are being used as phase locked loop (PLL) circuits for grid integration. Design of PLL circuits and the use of transformations such as Park’s and Clarke’s are much easier in three-phase systems. But obtaining in-phase and quadrature components becomes an important and challenging issue in single-phase systems. This article addresses this issue and discusses an altogether different application of GI for the design of compensator based on the extraction of in-phase and quadrature components. GI is frequently used as a PLL; however, in this article, it is not used for synchronisation purposes. A new controller has been designed for a single-phase grid-connected PV system working as a single-phase active compensator. Extensive simulation results are shown for the working of integrated PV system under different atmospheric and operating conditions during daytime as well as night conditions. Experimental results showing the proposed control approach are presented and discussed for the hardware set-up developed in the laboratory.     

Utilization of self-assembled AuGe nanoparticles for improving performance of InGaAs/GaAs quantum dot infrared detector

We report the successful realization of a plasmonic-based heptalayer self-assembled InGaAs quantum-dot infrared photodetector (QDIP) using self-assembled AuGe nanoparticles. In comparison with as-grown device, AuGe detector showed a 30% increase in spectral response at a peak of ~5 μm and ?1 V bias. We achieved two-order increment in peak responsivity of AuGe plasmonic-based detector in comparison to as-grown detector at 80 K. The improvements are attributed to increased light trapping in the device and strong plasmonic-QD interaction by the AuGe nanoparticles. In this technique, AuGe nanoparticles are self-assembled; therefore they don’t require very fine optical or e-beam lithography for patterning, indicating this technique will be helpful in reducing the cost of plasmonic based high-performance detectors.