Attenuation of Infrared Radiation When Passing Through a Water Curtain

This article focuses on the interaction of infrared (IR) radiation with water droplets. The main objective of the article is the production of water mist in order of evaluation the reduction in intensity of IR radiation. In the experiments described in this paper, a set of five different nozzles was used with various spray characteristics. The respective nozzles were gradually located between the IR radiation source and a detector and the attenuation of IR radiation was assessed. The reduction in IR radiation intensity was determined and IR radiation transmittance was calculated for the respective tested nozzles

Development of hybrid mobile applications and their usage in OR-SYSTEM Open information system

Bakalářská práce Vývoj hybridních mobilních aplikací a jejich využití v informačním systému OR-SYSTEM Open se zabývá porovnáním dostupných metod tvorby mobilních aplikací s konkrétním zaměřením na hybridní mobilní aplikace a popisem vývoje konkrétní hybridní mobilní aplikace. V práci jsou popsány současné trendy ve vývoji mobilních aplikací a základní přístupy k jejich vývoji. Práce dále popisuje jazyk JavaScript a další webové technologie jakožto nejpoužívanější jazyky pro tvorbu hybridních mobilních aplikací. V praktické části se práce zaměřuje na vývoj konkrétní mobilní hybridní aplikace komunikující s informačním systémem OR-SYSTEM Open.This bachelor thesis The development of hybrid mobile applications and their usage in OR-SYSTEM Open information system deals with comparison of available methods of creating mobile applications with in-depth look into hybrid mobile applications and description of development of specific hybrid mobile application. First part of this thesis describes trends in mobile app development and approaches to their development native mobile apps, mobile web pages and hybrid mobile apps. This thesis also describes JavaScript and other web development languages most used in hybrid mobile app development. Second part of this thesis describes the development of hybrid mobile application which communicates with the OR-SYSTEM Open information system

A new line-shape asymmetry model for wavelength modulation spectroscopy in gaseous flows

This communication reports technical notes on the development and application of an automated line-shape fitting procedure for wavelength modulation spectroscopy (WMS). Near-infrared transitions of carbon dioxide (CO2) around 1573 nm were measured in vertical cold (non-reacting) flow of CO2 at atmospheric pressure using WMS with demodulation at second harmonic frequency. Semi-empirical model based on the set of so-called Gabor functions was developed and parameters of Lorentzian line-shape profile and its asymmetry resulting from simultaneous frequency and amplitude response of the current-modulated semiconductor laser were determined. Nonlinear least-square fitting procedure employing differential evolution algorithm was successfully utilized for performing this task. Line-shape fitting procedure enabling efficient signal de-noising and background subtraction of wavelength modulation spectra was implemented into an open-source code.Web of Science18416115

ANALYSIS OF ENGINE PARAMETERS AT USING DIESEL-LPG AND DIESEL-CNG MIXTURE IN COMPRESSION-IGNITION ENGINE

Abstract This work is aimed on infl uence of diesel engine parameters that is used with mixture of gas and diesel fuel. The fi rst part of the article describes diesel fuel systems where small part of diesel fuel is replaced by LPG or CNG fuel. These systems are o en called as Diesel-Gas systems. Next part of the article focuses on tested car and measurement equipment. Measurement was performed by common-rail diesel engine in Fiat Doblò. Tests were carried out in laboratories of the Department of Engineering and Automobile Transport at the Mendel University in Brno. They were observed changes between emissions of used fuels -diesel without addition of gas, diesel + LPG and diesel + CNG mixture. It was found that that the addition of gas had positive eff ect on the performance parameters and emissions

Silicon micro-levers and a multilayer graphene membrane studied via laser photoacoustic detection

Laser photoacoustic spectroscopy (PAS) is a method that utilizes the sensing of the pressure waves that emerge upon the absorption of radiation by absorbing species. The use of the conventional electret microphone as a pressure sensor has already reached its limit, and a new type of microphone - an optical microphone -has been suggested to increase the sensitivity of this method. The movement of a micro-lever or a membrane is sensed via a reflected beam of light, which falls onto a position-sensing detector. The use of one micro-lever as a pressure sensor in the form of a silicon cantilever has already enhanced the sensitivity of laser PAS. Herein, we test two types of home-made sensing elements - four coupled silicon micro-levers and a multi-layer graphene membrane - which have the potential to enhance this sensitivity further. Graphene sheets possess outstanding electromechanical properties and demonstrate impressive sensitivity as mass detectors. Their mechanical properties make them suitable for use as micro-/nano-levers or membranes, which could function as extremely sensitive pressure sensors. Graphene sheets were prepared from multilayer graphene through the micromechanical cleavage of basal plane highly ordered pyrolytic graphite. Multilayer graphene sheets (thickness similar to 10(2) nm) were then mounted on an additional glass window in a cuvette for PAS. The movements of the sheets induced by acoustic waves were measured using an He-Ne laser beam reflected from the sheets onto a quadrant detector. A discretely tunable CO2 laser was used as the source of radiation energy for the laser PAS experiments. Sensitivity testing of the investigated sensing elements was performed with the aid of concentration standards and a mixing arrangement in a flow regime. The combination of sensitive microphones and micromechanical/nanomechanical elements with laser techniques offers a method for the study and development of new, reliable and highly sensitive chemical sensing systems. To our knowledge, we have produced the first demonstration of the feasibility of using four coupled silicon micro-levers and graphene membranes in an optical microphone for PAS. Although the sensitivity thus far remains inferior to that of the commercial electret microphone (with an S / N ratio that is 5 times lower), further improvement is expected to be achieved by adjusting the micro-levers and membrane elements, the photoacoustic system and the position detector.Web of Science4110910

Desorption/ablation of lithium fluoride induced by extreme ultraviolet laser radiation

The availability of reliable modeling tools and input data required for the prediction of surface removal rate from the lithium fluoride targets irradiated by the intense photon beams is essential for many practical aspects. This study is motivated by the practical implementation of soft X-ray (SXR) or extreme ultraviolet (XUV) lasers for the pulsed ablation and thin film deposition. Specifically, it is focused on quantitative description of XUV laser-induced desorption/ablation from lithium fluoride, which is a reference large band-gap dielectric material with ionic crystalline structure. Computational framework was proposed and employed here for the reconstruction of plume expansion dynamics induced by the irradiation of lithium fluoride targets. The morphology of experimentally observed desorption/ablation craters were reproduced using idealized representation (two-zone approximation) of the laser fluence profile. The calculation of desorption/ablation rate was performed using one-dimensional thermomechanic model (XUV-ABLATOR code) taking into account laser heating and surface evaporation of the lithium fluoride target occurring on a nanosecond timescale. This step was followed by the application of two-dimensional hydrodynamic solver for description of laser-produced plasma plume expansion dynamics. The calculated plume lengths determined by numerical simulations were compared with a simple adiabatic expansion (blast-wave) model.Web of Science61213813

Ablation of single-crystalline cesium iodide by extreme ultraviolet capillary-discharge laser

Extreme ultraviolet (XUV) capillary-discharge lasers (CDLs) are a suitable source for the efficient, clean ablation of ionic crystals, which are obviously difficult to ablate with conventional, long-wavelength lasers. In the present study, a single crystal of cesium iodide (CsI) was irradiated by multiple, focused 1.5-ns pulses of 46.9-nm radiation delivered from a compact XUV-CDL device operated at either 2-Hz or 3-Hz repetition rates. The ablation rates were determined from the depth of the craters produced by the accumulation of laser pulses. Langmuir probes were used to diagnose the plasma plume produced by the focused XUV-CDL beam. Both the electron density and electron temperature were sufficiently high to confirm that ablation was the key process in the observed CsI removal. Moreover, a CsI thin film on MgO substrate was prepared by XUV pulsed laser deposition; a fraction of the film was detected by X-ray photoelectron spectroscopy.Web of Science65421020