Deep inelastic electroproduction structure functions for polarized and unpolarized proton targets

Following Ioffe's method of QCD sum rules the structure functions F2(x) for deep inelastic ep and en scattering are calculated. Valence u-quark and d-quark distributions are obtained in the range 0.1 less, approximate x <0.4 and compared with data. In the case of polarized targets the structure function g1(x) and the asymmetry Image Full-size image are calculated. The latter is in satisfactory agreement in sign and magnitude with experiments for x in the range 0.1< x < 0.4.

A Novel Opto Electro Mechanical Interrogation System for Measuring Wavelength Shifts in Fiber Bragg Grating (FBG) Sensors

Here, we describe a novel FBG interrogation system in which FBGs are used as both sensing and reference elements. The reference FBGs is bonded to a mechanical flexure system having a linear amplification of 1:3.5, which is actuated using a piezo-actuator by applying a 0-150V ramp. The lengths of the reference gratings decide the maximum strain that can be applied to the reference grating, which in turn decides that strain range which can be interrogated. The main advantages of the present system are the on-line measurement of the wavelength shifts, small size, good sensitivity, multiplexing capability and low cost.

Partial Integrated Guidance and Control of Surface-to-Air Interceptors for High Speed Targets

An important limitation of the existing IGC algorithms, is that they do not explicitly exploit the inherent time scale separation that exist in aerospace vehicles between rotational and translational motions and hence can be ineffective. To address this issue, a two-loop partial integrated guidance and control (PIGC) scheme has been proposed in this paper. In this design, the outer loop uses a recently developed, computationally efficient, optimal control formulation named as model predictive static programming. It gives the commanded pitch and yaw rates whereas necessary roll-rate command is generated from a roll-stabilization loop. The inner loop tracks the outer loop commands using the Dynamic inversion philosophy. Uncommonly, Six-Degree of freedom (Six-DOF) model is used directly in both the loops. This intelligent manipulation preserves the inherent time scale separation property between the translational and rotational dynamics, and hence overcomes the deficiency of current IGC designs, while preserving its benefits. Comparative studies of PIGC with one loop IGC and conventional three loop design were carried out for engaging incoming high speed target. Simulation studies demonstrate the usefulness of this method.

CO2-laser induced X-ray emission from high density gaseous targets

A theory for the emission of X-rays from a high density gaseous plasma interacting with CO2 laser is given. It predicts a sharp increase in the X-ray intensity for densities close to the critical.

Theory of CO2-laser induced x-ray emission from high density gaseous targets

Abstract is not available.

Compact fiber Bragg grating dynamic strain sensor cum broadband thermometer for thermally unstable ambience

An instrument for simultaneous measurement of dynamic strain and temperature in a thermally unstable ambience has been proposed, based on fiber Bragg grating technology. The instrument can function as a compact and stand-alone broadband thermometer and a dynamic strain gauge. It employs a source wavelength tracking procedure for linear dependence of the output on the measurand, offering high dynamic range. Two schemes have been demonstrated with their relative merits. As a thermometer, the present instrumental configuration can offer a linear response in excess of 500 degrees C that can be easily extended by adding a suitable grating and source without any alteration in the procedure. Temperature sensitivity is about 0.06 degrees C for a bandwidth of 1 Hz. For the current grating, the upper limit of strain measurement is about 150 mu epsilon with a sensitivity of about 80 n epsilon Hz(-1/2). The major source of uncertainty associated with dynamic strain measurement is the laser source intensity noise, which is of broad spectral band. A low noise source device or the use of optical power regulators can offer improved performance. The total harmonic distortion is less than 0.5% up to about 50 mu epsilon, 1.2% at 100 mu epsilon and about 2.3% at 150 mu epsilon. Calibrated results of temperature and strain measurement with the instrument have been presented. Traces of ultrasound signals recorded by the system at 200 kHz, in an ambience of 100-200 degrees C temperature fluctuation, have been included. Also, the vibration spectrum and engine temperature of a running internal combustion engine has been recorded as a realistic application of the system.

Metabolic enzymes as potential drug targets in Plasmodium falciparum.

Plasmodium falciparum causes the most severe form of malaria that is fatal in many cases. Emergence of drug resistant strains of P. falciparum requires that new drug targets be-identified. This review considers in detail enzymes of the glycolytic pathway, purine salvage pathway, pyrimidine biosynthesis and proteases involved in catabolism of haemoglobin. Structural features of P. falciparum triosephosphate isomerase which could be exploited for parasite specific drug development have been highlighted. Utility of P. falciparum hypoxanthine-guanine-phosphoribosyltransferase, adenylosuccinate synthase, dihydroorotate dehydrogenase, thymidylate synthase-dihydrofolate reductase, cysteine and aspartic proteases have been elaborated in detail. The review also briefly touches upon other potential targets in P. falciparum

Strain-Temperature Discrimination Using a Single Fiber Bragg Grating

The out-diffusion of germanium from the core of a photosensitive fiber under elevated temperature is exploited to form a Fabry-Perot filter within a single fiber Bragg grating, by subjecting the diffused region to a single exposure using the standard phase-mask technique. A key aspect of our work is the measurement of the out-diffusion through energy dispersive X-ray analysis. Furthermore, we demonstrate the use of the above single-grating filter for discrimination and simultaneous measurement of strain and temperature. The proposed technique provides a significant advantage over other existing methods that require at least two gratings.

A Device to Crystallize Organic Solids: Structure of Ciprofloxacin, Midazolam, and Ofloxacin as Targets

The crystal structure determination of the anhydrous form of any organic compound has been a challenge because of solvent incorporation during crystallization. A device to grow anhydrous forms of low melting organic solids based on vaporization and condensation by a gradient cooling technique has been designed. Its utility has been evaluated by growing anhydrous forms of ciprofloxacin, midazolam, and ofloxacin. Ciprofloxacin crystallizes in triclinic P (1) over bar, midazolam in monoclinic P2(1)/n, and ofloxacin in the C2/c space group. Comparative studies on the conformational features with solvated structure show no significant variation in the aromatic moieties.

Fiber Bragg grating magnetic field sensor

In this paper we demonstrate experimentally a magnetic field sensor using a fiber Bragg grating. The shift in the Bragg condition as a result of strain applied on the fiber mounted on a nickel base by the magnetic field gives an indirect measure of the field. The proposed method overcomes the need for long fiber lengths required in methods such as Faraday effect sensors.

Detection of Tsunami Wave Generation and Propagation Using Fiber Bragg Grating Sensors

This paper describes the design and development of a Fiber Bragg Grating (FBG) sensor system for monitoring tsunami waves generated in the deep ocean. An experimental setup was designed and fabricated to simulate the generation and propagation of a tsunami wave. The characteristics and efficiency of the developed FBG sensor was evaluated with a standard commercial Digiquartz sensor. For real time monitoring of tsunami waves, FBG sensors bonded to a cantilever is used and the wavelength shifts (Delta lambda(B)) in the reflected spectra resulting from the strain/pressure imparted on the FBGs have been recorded using a high-speed Micron Optics FBG interrogation system. The parameters sensed are the signal burst during tsunami generation and pressure variations at different places as the tsunami wave propagates away from the source of generation. The results obtained were compared with the standard commercial sensor used in tsunami detection. The observations suggest that the FBG sensor was highly sensitive and free from many of the constraints associated with the commercial tsunameter.

Sensitivity of Lau fringes to grating rotation: theoretical analysis

Recently reported experimental results on the rotation sensitivity of Lau fringes to the spatial coherence of the source have been theoretically analyzed and explained on the basis of coherence theory. A theoretical plot of the rotation angle required for the Lau fringes to vanish is obtained as a function of the coherence length of the illumination used in the Lau experiment. The theoretical results compare well with the experimental observations. The analysis as well as the experiment could form the basis for a simple and easy measurement of the coherence length of the illumination in a plane.

Novel approach for simultaneous measurement of strain and temperature using a single tapered fiber Bragg grating

A novel approach for simultaneous measurement of strain and temperature with a single tapered fiber Bragg grating is proposed. This method is based on the fact that the reflectivity at central wavelength of FBG reflection changes with chirp (strain gradient). A diode laser is locked to the central wavelength of FBG reflection. Central wavelength of the FBG shifts with temperature. Change in reflectivity & wavelength of the diode laser were used to measure strain and temperature on the FBG respectively.

Simultaneous measurement of multiple parameters using a single fiber Bragg grating

A novel approach for simultaneous measurement of chirp (any parameter that can induce strain gradient on FBG) and temperature using a single FBG is proposed. Change in reflectivity at central wavelength of FBG reflection & Bragg wavelength shifts induced due to temperature were used for chirp & temperature measurements respectively. Theoretical resolution limit for chirp and temperature using an Optical Spectrum Analyzer (OSA) with 1pm wavelength resolution and >58dB dynamic range are 12.8fm and 1/13 degrees C respectively.