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Traditional monitoring systems in coal mines are difficult to install, hazardous, and difficult to power. Because of the complexity of the mining environment and the wide range of operations performed in coal mines, it is vital to monitor and maintain the parameters in the background t increase the efficiency and safety of mineworkers. As a result, traditional monitoring methods cannot be relied on to ensure coal workers’ safety. This research represents a ZigBee-based wireless monitoring system using a smart helmet. The presented wireless monitoring system is capable of detecting and transmitting critical parameters in coal mines such as methane gas, high temperature, humidity, and fire. In an emergency, this monitoring system transmits distress signals. A buzzer will sound if emergency conditions are detected, and the monitored variables will be displayed on the user interface machine. Moreover, the Parameters are wirelessly transmitted to the control room, allowing people to determine the safety situation of the mine. This model is easily reprogrammable. Experiments have demonstrated the system’s reliability and stability.

Silicon continues to draw great interest as an anode material for lithium ion batteries due to its large specific capacity for lithium. Macroporous silicon produced by electrochemical etching is one of several anode materials of interest, but its energy density is oftentimes limited due to its attachment to an unreactive silicon substrate. Here, we present a novel “lift-off” method by which a freestanding macroporous silicon film (MPSF) is electrochemically detached from the underlying bulk silicon and combined with pyrolyzed polyacrylonitrile (PAN), a conductive polymer that forms a conjugated-chain chemical structure. We report the performance of these silicon thin films with and without pyrolyzed PAN.

Silicon has the highest known theoretical charge capacity for lithium, making it a promising material for rechargeable lithium ion batteries (LIB). A significant drawback of silicon anodes is the large volume change associated with the insertion and extraction of lithium, which oftentimes leads to cracking and pulverization of the anode, limiting its cycle life. We present a layered architecture consisting of a gold-coated porous silicon film attached to a bulk silicon substrate. This structure demonstrates an enhanced ability to alloy with lithium ions over several charge/discharge cycles while maintaining mechanical integrity. With this structure we show that a specific capacity of over 3000 mAh g −1 can be achieved for over 50 charge–discharge cycles at 100 μA cm −2 , and 2500 mAh g −1 can be achieved for over 75 cycles with coulombic efficiencies over 95%. This is a significant improvement over a gold-coated, non-porous silicon sample, which had a maximum capacity of 1 mAh g −1 before failing after 10 cycles at 0.25 mAh g −1 when cycled at a constant current of 100 μA cm −2 , illustrating the benefit of internal pores. Gold-coated porous silicon out-performed non-gold-coated porous silicon, which had a first cycle discharge capacities of 500 mAh g −1 , which quickly faded to 76 mAh g −1 after the 10th cycle when cycled at a constant current of 50 μA cm −2 . The combination of internal pores and a gold-coating points to a new approach to improving the long-term cycleability and high-capacity performance metrics of LIB anodes.

Background: The uterine artery Doppler has potentials for screening for complications of impaired placentation. The purpose of study was to assess the role of uterine artery color Doppler waveform analysis in second trimester for the prediction of preeclampsia in a high-risk pregnancy between 18-24 weeks of gestation.Methods: 100 women with moderate or high-risk factors for developing preeclampsia reporting to Obstetrics and Gynaecology department of Government Medical College and Hospital, Sector 32, Chandigarh were enrolled for present study. Transabdominal uterine artery doppler measurements was done at 18-24weeks of gestation in these patients. Doppler . The Doppler indices generated automatically from the machine , the Pulsatility Index (PI), Resistance Index (RI) , presence or absence of diastolic notch and S/D Ratio were recorded, and average was calculated.Results: Out of 100 patients there were 46 primigravidas with no additional risk factors, 22 pateints with two or more risk factors and there were no patients who had three or more risk factors in present study population. Preeclampsia is seen more commonly in primigravida and primigravida is considered as moderate risk factor for preeclampsia. It was found that an elevated second trimester uterine artery RI was significantly associated with developing preeclampsia later in pregnancy. The sensitivity and specificity of uterine artery Doppler velocimetry were found to be 84% and 55% respectively. Receiver operator characteristics (ROC) curves were created to demonstrate the prognostic value of RI and PI of uterine artery doppler indices at 18-24 weeks of gestation for the development preeclampsia. In addition, there were statistically significant positive correlations between mean RI of uterine artery doppler study and patients who developed preeclampsia. With a sensitivity of 84.21% it could identify 31% of the cases of preeclampsia at a false positive rate of 44.4%.Conclusions: Uterine artery doppler study can be used as a predictor of moderate strength for preeclampsia.

In this paper, the surface profile of objects is determined by using a grating projection system. The method is based on the concept of self-imaging, namely, the Lau effect. Periodic fringe patterns are generated from the projection of a grating illuminated by multiple mutually incoherent quasi-plane wavefront. The fringe patterns are then projected on to the object surface and the deformed grating image is captured by a CCD camera for subsequent analysis. Phase shifting techniques have been employed to determine the phase value. With suitable calibration of the system and the phase value obtained, the surface profile of the objects can be determined. The phase variation is achieved by using a linear translation stage incorporated to the grating. In this study, two specimens are tested to demonstrate the validity of the method. One is a spherical cap with a height of 4 mm, and the other is a coin. The experimental results are compared with results obtained by mechanical stylus method. In the case of the spherical cap the results are also compared with fringe projection method based on Talbot effect.

In this paper, we have demonstrated experimentally the vibration analysis of a reflecting object in a time-averaged mode using Lau phase interferometry. Experimental results provide information about the tilt at every point of a vibrating plate. The Lau phase interferometry is robust and simple. Experimental results are compared with conventional shadow-moire method.

In this paper, we proposed a phase shifting Lau phase interferometry for the measurement of the focal length of a lens. The fundamentals of this application are discussed and the basis of the phase map interpretation is outlined. A three step phase-shifting algorithm is used to depict the phase maps of a lens-like test object and an application for measuring the focal length of a lens is reported. A phase map obtained with a coherent light source is also shown and the merits of using incoherent light over coherent light source are also discussed. Experimental results are presented.

In this paper we have investigated the utility of Lau phase interferometer with linear gratings and white light source to measure temperature and temperature profile of an axisymmetric flame. The temperature measured using Lau phase interferometer is in good agreement with the temperature measured with thermocouple and datalogger. Details of theoretical analysis and experimental investigation are presented.

Measurement of accurate spatial distribution of temperature and temperature fluctuation in a flame is important to study the combustion process in detail. In this paper first we have presented measurement of temperature profile of a gaseous flame of a two-dimensional slot burner. The errors due to halo effect in the measurements of temperature are minimized by correcting the width of the fringes. Further single exposure speckle photography is used to study temperature fluctuation inside the flame. The 3-D plot of temperature fluctuation for different fuel flow rates of air and acetylene at different vertical heights above the mouth of the burner with distance from the one end of the burner is also presented.

Lithium-ion batteries are ubiquitous in our modern society, powering everything from cell phones, laptops, and power tools.They are also powering emerging applications such as electric vehicles and used for on-grid power stabilization. Lithium-ion batteries are a significant and growing part of this market due to their high specific energy. The worldwide market for lithium-ion batteries is projected to reach more than USD 9 billion by 2015. While lithium-ion batteries are often selected for their high specific energy, the market is demanding yet higher performance, usually in terms of energy stored per unit mass of battery. Many groups have recently turned their attention toward developing a silicon-based anode material to increase lithium-ion battery density. Silicon continues to draw great interest as an anode for lithium-ion batteries due to its large specific capacity as compared to the conventional graphite. Despite this exciting property, its practical use has been limited due to a large volume change associated with the insertion and extraction of lithium, which oftentimes leads to cracking and pulverization of the anode, limiting its cycle life. To overcome this problem, significant research has been focused toward developing various silicon nanostructures to accommodate the severe volume expansion and contraction. The structuring of the silicon often involves costly processing steps, limiting its application in price sensitive commercial lithium-ion batteries. To achieve commercial viability, work is being pursued on silicon battery anode structures and processes with a special emphasis on the cost and environment. In this review book chapter, we will summarize recent development of a cost-effective electrochemically etched porous silicon as an anode material for lithium-ion batteries. Briefly, the new approach involves creating hierarchical micron-and nanometer-sized pores on the surface of micron-sized silicon particulates, which are combined with an excellent conductor binder.

One of the most exciting areas in lithium ion batteries is engineering structured silicon anodes. These new materials promise to lead the next generation of batteries with significantly higher reversible charge capacity than current technologies. One drawback of these materials is that their production involves costly processing steps, limiting their application in commercial lithium ion batteries. In this report we present an inexpensive method for synthesizing macroporous silicon particulates (MPSPs). After being mixed with polyacrylonitrile (PAN) and pyrolyzed, MPSPs can alloy with lithium, resulting in capacities of 1000 mAhg(-1) for over 600+ cycles. These sponge-like MPSPs with pyrolyzed PAN (PPAN) can accommodate the large volume expansion associated with silicon lithiation. This performance combined with low cost processing yields a competitive anode material that will have an immediate and direct application in lithium ion batteries.

A wide-field four-channel fluorescence imager has been developed. The instrument uses four expanded laser beams to image a large section (6 mm x 9 mm). An object can be sequentially illuminated with any combination of 408-, 532-, 658-, and 784-nm lasers for arbitrary (down to 1 ms) exposure times for each laser. Just two notch filters block scattered light from all four lasers. The design approach described here offers great flexibility in treatment of objects, very good sensitivity, and a wide field of view at low cost. There appears to be no commercial instrument capable of simultaneous fluorescence imaging of a wide field of view with four-laser excitation. Some possible applications are following events such as flow and mixing in microchannel systems, the transmission of biological signals across a culture, and following simulations of biological membrane diffusion. It can also be used in DNA sequencing by synthesis to follow the progress of the photolytic removal of dye and terminator. Without utilizing its time resolution, it can be used to obtain four independent images of a single tissue section stained with four targeting agents, with each coupled to a different dye matching one of the lasers.

Talbot interferometry is used to study the surface profile of a transparent object. Periodic patterns are produced by illuminating a grating with a collimated laser beam. The object is placed on the self-image plane of the grating. The deformed grating image, which interferes with another grating, results in the Talbot interferometric fringes. The fringe pattern is recorded on a CCD camera for subsequent analysis, and the phase variation is achieved by a linear translation stage. In this application two specimens are tested to demonstrate the validity of the method; one is a transparent object with a spherical shape with a height of less than 350 microm, and the other is a transparent object with an uneven surface of 50-microm average height. The experimental results are compared with the test results obtained with the mechanical stylus method.

A grating projection system is a low-cost surface contour measurement technique that can be applied to a wide range of applications. There has been a resurgence of interest in the technique in recent years because of developments in computer hardware and image processing algorithms. We describe a method that projects a phase-shifted grating through a lens on an object surface. The deformed grating image on the object surface is captured by a CCD camera for subsequent analysis. Phase variation is achieved by a linear translation stage on which the grating is mounted. We compare the experimental results with the test results using a mechanical stylus method.

We used a white-light Lau phase interferometer to evaluate the focal distances of two lenses. We found that the variation in the experimentally measured value is less than +/-1% from the given values. Limitations of the method and error analysis are presented.

In this paper we have investigated the utility of Lau phase interferometer with white light source and circular gratings to measure temperature and temperature profile of an axisymmetric flame. In Lau phase interferometer the two gratings are separated by infinite distance. The third grating is placed at a distance Z equals n.p 2 (lambda) , (where n is an integer, d is the pitch of the grating and (lambda) is the wavelength of the white light source). The sensitivity of the system is determined by the pitch 'p' of the grating and the distance Z between the gratings. If the distance Z between the two gratings is increased to enhance the sensitivity, the accuracy of measurement is reduced because of the reduction in the fringe contrast. In white light Lau phase interferometer the fringe contrast can be improved by optimizing the self-image plane and the pitch of the grating. From the recorded interferogram the angle of deflection ((phi) ) is measured and temperature at a different point of the flame is calculated. The temperature measured using Lau phase interferometer is in good agreement with the temperature measured by thermocouple and dataloger. Details of the theoretical analysis and experimental results are presented.

We present a novel method to tune the interaction potential from 5kBT to 40kBT in situ between micron-sized superparamagnetic colloids. The potential is composed of a highly tunable long-range attraction induced via a rotating magnetic field and a short-range electrostatic repulsion. Various 2-D thermodynamic phases are observed in a colloidal suspension at different field strengths. Quantitative agreement is found between theory and experiments for dipolar interactions. A theory to account for the induced dipole due to neighboring particles is also presented. The effective three-body potential of a dilute trimer system is measured to account for many-body effects in the system. These results demonstrate an ideal model to study the phase behavior in 2-D systems.

We have investigated the utility of a Lau phase interferometer with circular gratings and a white-light source to measure the temperature and temperature profile of an axisymmetric flame. The temperature measured with a Lau phase interferometer is in good agreement with the temperature measured with a thermocouple and multilogger. Detailed theoretical analysis and experimental investigation are presented.