Atomic Force Microscopy as a Nanometrology Tool: Some Issues and Future Targets

Diverse novel nanomaterials are being developed for a wide range of applications nowadays. Atomic force microscopy (AFM) assumes specific importance for the measurement of size and other related properties for such nanomaterials. The different aspects related to AFM modes of operation, nanopositioning, sensing systems as well as calibration for reliable characterization in order to meet the nanometrology requirements are discussed. The future targets in this context, set by nanometrology institutes, are also highlighted.     

Mean LBP and modified fuzzy C-means weighted hybrid feature for illumination invariant mean-shift tracking

Object tracking is a critical task in surveillance and activity analysis. Two main issues for tracking are appearance (illumination) and structural (size of a target) variations of the object. We propose a method which is robust and addresses these issues by incorporating features that are less variant to these changes. The proposed features are mean local binary pattern (mLBP), an illumination invariant texture feature, and modified fuzzy c-means (MFCM) weighted color histogram to handle both illumination and scale changes. These features are combined to form a hybrid mean-shift (MS) vector and used in the MS vector framework for target tracking. Experimental results using standard benchmark videos show that the proposed scheme can lead to better localization and robust tracking in challenging illumination scenarios, when compared to several existing tracking algorithms.     

Simultaneous Radar Observations of Vertical Profile of Rain Features from Space and Ground at Ku and Ka Bands at a Tropical Location

In this paper parameters of precipitation profiles obtained from precipitation radar aboard tropical rainfall measuring mission satellite and from ground based micro rain radar observations have been compared for different rain events. The dual frequency radar observations of precipitating atmosphere have been utilized to study the vertical profiles of radar reflectivity and rain rate. It is shown that the inclination of the ray path of the satellite borne radar significantly influences the rain rate measurements. The study demonstrates the efficacy of combining space borne and ground-based measurement in obtaining a complete profile of vertical rain structure.     

The Case for Quantitative Process Management

This article introduces a special section on "Embedding Statistical Methods into Software Engineering Practices." It provides a background on Quantitative Process Management and makes the case for why these methods are important. It presents an example of how a model can be developed to predict project outcomes by using data emerging from the performance of process tasks. It discusses how these methods can be used with different software development paradigms. It ends by summarizing develops needed in five different communities in order for these methods to be widely adopted.     

Mortality of globally threatened Sarus cranes Grus antigon from monocrotophos poisoning in India

Globally threatened Sarus cranes Grus antigon are resident at Keoladeo National Park World Heritage site and the surrounding area near Bharatpur, Western Rajasthan, India. In winter, they are joined by c. 200 wintering common cranes Grus grus. On 23 November 2000, 15 Sarus cranes and three common cranes were found dead in a field adjacent to the park, where wheat seed had been sown the previous day. Chemical analyses of seed samples from the field and the cranes' alimentary tract contents identified residues of the organophosphate insecticide monocrotophos. Monocrotophos concentrations of 0.8 and 1.8 ppm were found in wheat samples, and 0.2-0.74 ppm (x=0.33) in the alimentary tract contents of five of the seven cranes examined. No other organophosphate or organochlorine pesticides were detected. We conclude that the cranes died from monocrotophos poisoning after eating treated seed. We discuss similar incidents of avian mortality, and recommend that measures be taken to reduce these.     

Self organization of granular flow by basal friction variation: Natural jump,moving bore,and flying avalanche

The article discusses the response of rapid granular downslope flow to an abrupt change in basal friction. Although granular discharge from silo and hoppers has received considerable attention in the past, the flow behavior for an abrupt change in basal friction is hitherto unexplored. In the present study, the channel floor comprises of a smooth surface (bed friction angle—δ_S) and a rough surface (bed friction angle—δ_R) such that the angle of repose of the granular material (θ_r) lies between δ_S and δ_R and the flow features are observed as the channel inclination (θ) is varied from ≈δ_S to >δ_R. Experiments are performed in two channels with different extent of rough surface for two grain sizes with the same angle of repose and different inlet depth of granular flow. The visualization studies reveal a rich variety of flow features namely moving bore, rapid granular flow, flying avalanche and granular jump. Natural granular jump formed by mere frictional dissipation without any external forcing has not been reported earlier. The variety of flow features primarily results from the interplay of downslope motion of variable depth, collision-driven piling of grains, and slope shaving avalanches. The observed flow phenomena have been satisfactorily analyzed by the well-known depth-averaged avalanche flow equations under conditions of incompressible granular flow.     

Numerical simulation and modelling of a novel MEMS capacitive accelerometer based microphone for fully implantable hearing aid

Microsystem Technologies - The present work proposes a novel MEMS capacitive accelerometer based microphone with enhanced sensitivity. The accelerometer design is simulated in COMSOL MULTIPHYSICS...     

Study of the tunnelling initiated leakage current through the carbon nanotube embedded gate oxide in metal oxide semiconductor structures

The tunnelling currents through the gate dielectric partly embedded with semiconducting single-wall carbon nanotubes in a silicon metal-oxide-semiconductor (MOS) structure have been investigated. The application of the gate voltage to such an MOS device results in the band bending at the interface of the partly embedded oxide dielectric and the surface of the silicon, initiating tunnelling through the gate oxide responsible for the gate leakage current whenever the thickness of the oxide is scaled. A model for silicon MOS structures, where carbon nanotubes are confined in a narrow layer embedded in the gate dielectric, is proposed to investigate the direct and the Fowler-Nordheim (FN) tunnelling currents of such systems. The idea of embedding such elements in the gate oxide is to assess the possibility for charge storage for memory device applications. Comparing the FN tunnelling onset voltage between the pure gate oxide and the gate oxide embedded with carbon nanotubes, it is found that the onset voltage decreases with the introduction of the nanotubes. The direct tunnelling current has also been studied at very low gate bias, for the thin oxide MOS structure which plays an important role in scaling down the MOS transistors. The FN tunnelling current has also been studied with varying nanotube diameter.     

Junctionless double gate non-parabolic variable barrier height Si-MOSFET for energy efficient application

Microsystem Technologies - Analytical model for the computation of drain current of the junction-less double gate junction-less MOSFET with a variable barrier height has been presented in this...     

Study of surface morphology and optical properties of Nb<Subscript>2</Subscript>O<Subscript>5</Subscript> thin films with annealing

Nb₂O₅ films have been deposited on variety of substrates using the sol-gel dip coating technique. As-deposited films on all substrates are amorphous. Films were annealed under controlled ambience at 300, 400 and 600°C for 5 h. As-deposited films on glass substrate show uniform surface structure. The crystal structure and surface topography are found to depend strongly on the annealing temperature and nature of the substrates. The average grain size of 40 nm is observed in films annealed at 300°C. On annealing at 400°C increasing grain size and resulting fusing of them, enhanced surface roughness. Films deposited on NaCl substrates crystallized into a stable monoclinic phase and those deposited on single crystal Si substrates crystallized into hexagonal phase after annealing at 600°C. The as-deposited films show very high transmittance (>90%) in the visible region. The optical band gap is observed to increase from 4.35 eV when the films are in amorphous state to 4.87 eV on crystallization.