5,296,903 research outputs found

    The Effect of Thermal Fluctuations on Schulman Area Elasticity

    Full text link
    We study the elastic properties of a two-dimensional fluctuating surface whose area density is allowed to deviate from its optimal (Schulman) value. The behavior of such a surface is determined by an interplay between the area-dependent elastic energy, the curvature elasticity, and the entropy. We identify three different elastic regimes depending on the ratio Ap/AsA_p/A_s between the projected (frame) and the saturated areas. We show that thermal fluctuations modify the elastic energy of stretched surfaces (Ap/As>1A_p/A_s> 1), and dominate the elastic energy of compressed surfaces (Ap/As<1A_p/A_s< 1). When ApAsA_p\sim A_s the elastic energy is not much affected by the fluctuations; the frame area at which the surface tension vanishes becomes smaller than AsA_s and the area elasticity modulus increases.Comment: 12 pages, to appear in Euro. Phys. J.

    Temperature-dependent optical properties of plasmonic titanium nitride thin films

    Full text link
    Due to their exceptional plasmonic properties, noble metals such as gold and silver have been the materials of choice for the demonstration of various plasmonic and nanophotonic phenomena. However, noble metals' softness, lack of tailorability and low melting point along with challenges in thin film fabrication and device integration have prevented the realization of real-life plasmonic devices.In the recent years, titanium nitride (TiN) has emerged as a promising plasmonic material with good metallic and refractory (high temperature stable) properties. The refractory nature of TiN could enable practical plasmonic devices operating at elevated temperatures for energy conversion and harsh-environment industries such as gas and oil. Here we report on the temperature dependent dielectric functions of TiN thin films of varying thicknesses in the technologically relevant visible and near-infrared wavelength range from 330 nm to 2000 nm for temperatures up to 900 0C using in-situ high temperature ellipsometry. Our findings show that the complex dielectric function of TiN at elevated temperatures deviates from the optical parameters at room temperature, indicating degradation in plasmonic properties both in the real and imaginary parts of the dielectric constant. However, quite strikingly, the relative changes of the optical properties of TiN are significantly smaller compared to its noble metal counterparts. Using simulations, we demonstrate that incorporating the temperature-induced deviations into the numerical models leads to significant differences in the optical responses of high temperature nanophotonic systems. These studies hold the key for accurate modeling of high temperature TiN based optical elements and nanophotonic systems for energy conversion, harsh-environment sensors and heat-assisted applications.Comment: 23 pages, 9 figures and 5 table

    Low temperature stimulates spatial molecular reprogramming of the Arabidopsis seed germination programme

    Get PDF
    The timing of the germination of seeds is highly responsive to inputs from the environment. Temperature plays a key role in the control of germination, with low temperatures acting to stimulate this developmental transition in many species. In Arabidopsis, extensive gene expression changes have been reported at the whole seed level in response to cold, while much less is known about their spatial distribution across the diverse cell types of the embryo. In this study we examined the spatiotemporal patterns of promoter activity and protein abundance for key gibberellic acid (GA) and abscisic acid (ABA) factors which regulate the decision to germinate both during a time course of germination and in response to cold. Low temperature stimulated the spatial relocalization of these factors to the vasculature. The response of these seeds to dormancy-breaking stratification treatments therefore stimulates the distribution of both positive (GA) and negatively acting (ABA) components to this same cell type. This altered spatial pattern persisted following the transfer of seeds to 22°C, as well as after their rehydration, indicating that this alteration is persistent. These observations suggest that the vasculature plays a role in the low temperature-mediated stimulation of germination in this species, while novel cell types are recruited to promote germination in response to stratification

    Modelling of Temperature in Full-scale Systems: a Review of the Biological Heat Generation Within Windrow Composting

    Full text link
    Windrow composting is the most common method for organic solid waste treatment. Temperature is an important state variable in modelling, which could be simulated by estimating the change of heat balance components at any moment. Biological heat energy is the most significant term in the heat balance. In this paper biological heat generation of the composting process are examined and their applicability for a full-scale windrow system is evaluated. It is found that, to date, the accuracy of predicting the rate of substrate degradation has been a major challenge. The use of an inductive approach based on either first-order kinetic expression or empirical kinetics relation was found to be more feasible for practical purposes. However a scale-up correction factor for particular processes and types of substrate may need to be further investigated to narrow the discrepancies of kinetic performances between laboratory and full-scale systems

    Patient Monitor for SpO2 and Temperature Parameters

    Full text link
    Patient monitor is an apparatus used to monitor the patient\u27s condition in real-time, hence the patient\u27s physiological conditions can be identified at that time. The purpose of this study is to design a patient monitor for SpO2 and temperature parameters based on computer with Delphi progaming. In this work, the author developed&nbsp; patient monitor with two parameters (SpO2 and Temperature). The workings of this tool are very simple by installing the finger sensor on the finger and the temperature sensor in the armpit area will then be detected by the two sensors that will be displayed on the PC and LCD Characters, analog data from the ADC Atmega is received by the personal computer (PC) via Bluetooth HC -05 and values ​​per parameter are also displayed on the Character LCD. After measuring, get an error in the tool, the biggest SpO2 error of this tool is 1.02% and get the smallest error of 0.8%. And for the biggest error of Temperature of 1.02% and the smallest error of 0.8%

    Finite temperature spin dynamics in a perturbed quantum critical Ising chain with an E8E_8 symmetry

    Get PDF
    A spectrum exhibiting E8E_8 symmetry is expected to arise when a small longitudinal field is introduced in the transverse-field Ising chain at its quantum critical point. Evidence for this spectrum has recently come from neutron scattering measurements in cobalt niobate, a quasi one-dimensional Ising ferromagnet. Unlike its zero-temperature counterpart, the finite-temperature dynamics of the model has not yet been determined. We study the dynamical spin structure factor of the model at low frequencies and nonzero temperatures, using the form factor method. Its frequency dependence is singular, but differs from the diffusion form. The temperature dependence of the nuclear magnetic resonance (NMR) relaxation rate has an activated form, whose prefactor we also determine. We propose NMR experiments as a means to further test the applicability of the E8E_8 description for CoNb2_2O6_6.Comment: 5 pages 2 figures - Supplementary Material 11 page

    Effect of Temperature on PH Meter Based on Arduino Uno with Internal Calibration

    Full text link
    PH Meter is a device used to express the level of acidity or basicity possessed by a substance or solution. Normal pH has a value of 7 while the pH value&gt; 7 indicates that the substance has alkaline properties while the pH value &lt;7 indicates acidic properties. pH 0 shows a high degree of acidity, and pH 14 shows the highest degree of alkalinity. pH Meter reads the pH and temperature values ​​in a sample. The author uses glass electrodes as a pH sensor, DS18B20 as a temperature sensor and LCD to make pH and temperature values. This module is equipped with an internal calibration that is used to set the module to read the pH value properly and correctly using a pH buffer and equipped with internal storage and this module facilitates battery usage. Based on pH measurements on the module the error value in buffer 4 calibration is 5.39%, in buffer 7 is 1.76%, in buffer 10 is 1.04%. The highest error value in the measurement sample is 3.54% and the lowest error value is 0.03%. The temperature of the sample is very influential on the reading of the pH value because the higher the temperature the pH value also increases even though it is not so significant
    corecore