1,297 research outputs found

    Formulation and statistical evaluation of a ready-to-drink whey based orange beverage and its storage stability

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    A value-added functional beverage is formulated utilizing unprocessed liquid whey. Whey has excellent nutritional qualities and bland flavors; it is easy to digest and has a unique functionality in a beverage system. The ready-to-drink beverage is formulated with concentrated whey, orange juice along with an adequate amount of sugar, stabilizer, citric acid and flavor. Orange juice is used since the acidic flavor of whey is compatible With citrus flavors and particularly orange. The health and nutrition benefits of orange further imparts the value to the formulated beverage. Nine blend formulations are prepared by varying the dry matter of whey, fruit juice and sugar content Based on a statistical analysis of the sensory evaluation of the drinks, the optimal formulation is found to have a ratio 3:2 for concentrated liquid whey and orange juice followed by an addition of 8% sugar (w/v) and 0.1% stabilizer (w/v). The shelf-life of the final product is carried out both at room temperature (30+/-2 degrees C) and refrigeration temperature (7+/-1 degrees C) with and without addition of preservatives. The product remains in good condition up to eleven days at room temperature and up to three months under refrigeration condition with addition of 150 ppm of sodium benzoate

    Contrasting levels of absorption of intense femtosecond laser pulses by solids

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    The absorption of ultraintense, femtosecond laser pulses by a solid unleashes relativistic electrons, thereby creating a regime of relativistic optics. This has enabled exciting applications of relativistic particle beams and coherent X-ray radiation, and fundamental leaps in high energy density science and laboratory astrophysics. Obviously, central to these possibilities lies the basic problem of understanding and if possible, manipulating laser absorption. Surprisingly, the absorption of intense light largely remains an open question, despite the extensive variations in target and laser pulse structures. Moreover, there are only few experimental measurements of laser absorption carried out under very limited parameter ranges. Here we present an extensive investigation of absorption of intense 30 femtosecond laser pulses by solid metal targets. The study, performed under varying laser intensity and contrast ratio over four orders of magnitude, reveals a significant and non-intuitive dependence on these parameters. For contrast ratio of 10-9 and intensity of 2 × 1019W cm-2, three observations are revealed: preferential acceleration of electrons along the laser axis, a ponderomotive scaling of electron temperature, and red shifting of emitted second-harmonic. These point towards the role of J × B absorption mechanism at relativistic intensity. The experimental results are supported by particle-in-cell simulations

    Overcoming Bifurcation Instability in High-Repetition-Rate Ho:YLF Regenerative Amplifiers

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    We demonstrate a Ho:YLF regenerative amplifier (RA) overcoming bifurcation instability and consequently achieving high extraction energies of 6.9 mJ at a repetition rate of 1 kHz with pulse-to-pulse fluctuations of 1.1%. Measurements of the output pulse energy, corroborated by numerical simulations, identify an operation point that allows high-energy pulse extraction at a minimum noise level. Complete suppression of the onset of bifurcation was achieved by gain saturation after each pumping cycle in the Ho:YLF crystal via lowering the repetition rate and cooling the crystal. Even for moderate cooling, a significant temperature dependence of the Ho:YLF RA performance was observed

    Probing ultrafast dynamics in a solid-density plasma created by an intense femtosecond laser

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    We report a study on the dynamics of a near-solid density plasma using an ultraviolet (266 nm) femtosecond probe laser pulse, which can penetrate to densities of ∼ 1022 cm-3, nearly an order of magnitude higher than the critical density of the 800 nm, femtosecond pump laser. Time-resolved probe-reflectivity from the plasma shows a rapid decay (picosecond- timescale) while the time-resolved reflected probe spectra show red shifts at early temporal delays and blue shifts at longer delays. This spectral behaviour of the reflected probe can be explained by a laser-driven shock moving inward and a subsequent hydrodynamic free expansion in the outward direction

    Efficient transport of femtosecond laser-generated fast electrons in a millimeter thick graphite

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    We demonstrate efficient transport of fast electrons generated by ∼1018 W/cm2, 30 fs, 800 nm laser pulses through a millimeter thick polycrystalline graphite. Measurements of hot electron spectra at the front side of the graphite target show enhancement in terms of the electron flux and temperature, while the spectra at the rear confirm the ability of the graphite to transport large electron currents over a macroscopic distance of a millimeter. In addition, protons of keV energies are observed at the rear side of such a macroscopically thick target and attributed to the target-normal-sheath-acceleration mechanism

    Controlling femtosecond-laser-driven shock-waves in hot, dense plasma

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    Ultrafast pump-probe reflectometry and Doppler spectrometry of a supercritical density plasma layer excited by 1017-1018 W/cm2 intensity, 30 fs, and 800 nm laser pulses reveal the interplay of laser intensity contrast and inward shock wave strength. The inward shock wave velocity increases with an increase in laser intensity contrast. This trend is supported by simulations as well as by a separate independent experiment employing an external prepulse to control the inward motion of the shock wave. This kind of cost-effective control of shock wave strength using femtosecond pulses could open up new applications in medicine, science, and engineering

    Formation and evolution of post-solitons following a high intensity laser-plasma interaction with a low-density foam target

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    The formation and evolution of post-solitons has been discussed for quite some time both analytically and through the use of particle-in-cell (PIC) codes. It is however only recently that they have been directly observed in laser-plasma experiments. Relativistic electromagnetic (EM) solitons are localised structures that can occur in collisionless plasmas. They consist of a low-frequency EM wave trapped in a low electron number-density cavity surrounded by a shell with a higher electron number-density. Here we describe the results of an experiment in which a 100 TW Ti:sapphire laser (30 fs, 800 nm) irradiates a 0:03 gcm^-3 TMPTA foam target with a focused intensity I_l = 9:5x10^17 Wcm^-2. A third harmonic (lambda_probe ~ 266 nm) probe is employed to diagnose plasma motion for 25 ps after the main pulse interaction via Doppler-Spectroscopy. Both radiation-hydrodynamics and 2-D PIC simulations are performed to aid in the interpretation of the experimental results. We show that the rapid motion of the probe critical-surface observed in the experiment might be a signature of post-soliton wall motion
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