1,404 research outputs found

    Deformations of the Boson sp(4,R)sp(4,R) Representation and its Subalgebras

    Full text link
    The boson representation of the sp(4,R) algebra and two distinct deformations of it, are considered, as well as the compact and noncompact subalgebras of each. The initial as well as the deformed representations act in the same Fock space. One of the deformed representation is based on the standard q-deformation of the boson creation and annihilation operators. The subalgebras of sp(4,R) (compact u(2) and three representations of the noncompact u(1,1) are also deformed and are contained in this deformed algebra. They are reducible in the action spaces of sp(4,R) and decompose into irreducible representations. The other deformed representation, is realized by means of a transformation of the q-deformed bosons into q-tensors (spinor-like) with respect to the standard deformed su(2). All of its generators are deformed and have expressions in terms of tensor products of spinor-like operators. In this case, an other deformation of su(2) appears in a natural way as a subalgebra and can be interpreted as a deformation of the angular momentum algebra so(3). Its representation is reducible and decomposes into irreducible ones that yields a complete description of the same

    CHARACTERIZATION OF RF AND DC MAGNETRON REACTIVE SPUTTERED TiO 2 THIN FILMS FOR GAS SENSORS

    Get PDF
    This study presents the technology for prep aring and characterization of titanium oxide thin films with proper ties suitable for gas sensors. For preparing the samples the reactive radio frequency (RF) and direct current (DC) magnetron sputtering methods were used. The composition and microstructure of the films were studied by X-ray photoelectron spectroscopy (XPS), X-ray diff raction (XRD) and Raman spectroscopy, the surface of the films was observed applying high-resolution scanning electron microscopy (SEM). For measuring the thickness and identifying the refractive indices of the films laser ellipsometry was used. The research was focuse d on the sensing behavior of the sputtered titania thin films applying quartz crystal microbalance (QCM) method, which allows detection of mass changes in the nanogram range. Prototype QCM sensors with TiO 2 thin films were made by our team and tested for sensitivity to NH 3 and NO 2 . These films even in as-deposited state and without heating th e substrates show good sensitivity. Additional thermal treatment is not necessary, making manufacturing of QCM gas sensor simple and cost-effective, as it is fully compatible with the technology for producing the initial resonator. The sorption is fully reversible and the studied TiO 2 films are stable, which makes them capable for meas urements for long terms

    Staggering behavior of the low lying excited states of even-even nuclei in a Sp(4,R) classification scheme

    Full text link
    We implement a high order discrete derivative analysis of the low lying collective energies of even-even nuclei with respect to the total number of valence nucleon pairs N in the framework of F- spin multiplets appearing in a symplectic sp(4,R) classification scheme. We find that for the nuclei of any given F- multiplet the respective experimental energies exhibit a Delta N=2 staggering behavior and for the nuclei of two united neighboring F- multiplets well pronounced Delta N=1 staggering patterns are observed. Those effects have been reproduced successfully through a generalized sp(4,R) model energy expression and explained in terms of the step-like changes in collective modes within the F- multiplets and the alternation of the F-spin projection in the united neighboring multiplets. On this basis we suggest that the observed Delta N=2 and Delta N=1 staggering effects carry detailed information about the respective systematic manifestation of both high order alpha - particle like quartetting of nucleons and proton (neutron) pairing interaction in nuclei.PACS number(s):21.10.Re, 21.60.FwComment: 22 pages and 6 figures changes in the figure caption

    Miniaturized Gas Correlation Radiometer for the Detection of Trace Gases in the Martian Atmosphere

    Get PDF
    We present a miniaturized and simplified version of a gas correlation radiometer (GCR) capable of simultaneously mapping multiple trace gases and identifying active regions on the Mars surface. Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Reduction of the size and mass of the GCR was achieved by implementing compact, light-weight 1 mm inner diameter hollow-core optical fibers (hollow waveguides) as the gas correlation cells. In a comparison with an Earth orbiting CO2 GCR instrument, exchanging the 10 m multipass cells with hollow waveguide gas correlation cells of equivalent path length reduces the mass from approximately 150 kg to approximately 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately 1 meter in diameter by 0.05 m in height (mass and volume reductions of greater than 99%). A unique feature of this instrument is its stackable module design, with a single module for each trace gas. Each of the modules is self-contained, and fundamentally identical; differing by the bandpass filter wavelength range and gas mixtures inside the hollow-waveguide absorption cells. The current configuration contains four stacked modules for simultaneous measurements of methane (CH4), formaldehyde (H2CO), water vapor (H2O), and deuterated water vapor (HDO) but could easily be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance. Preliminary results indicate that a 1 ppb detection limit is possible for both formaldehyde and methane with one second of averaging. Using non-optimized components, we have demonstrated an instrument sensitivity equivalent to approximately 30 ppb for formaldehyde, and approximately 500 ppb for methane. We expect custom bandpass filters and 6 m long waveguides to significantly improve these promising results. Ongoing testing is being conducted on water vapor and deuterated water vapor

    Evaluation of behavioral changes and subjective distress after exposure to coercive inpatient interventions

    Get PDF
    BACKGROUND: There is a lack of evidence to underpin decisions on what constitutes the most effective and least restrictive form of coercive intervention when responding to violent behavior. Therefore we compared ratings of effectiveness and subjective distress by 125 inpatients across four types of coercive interventions. METHODS: Effectiveness was assessed through ratings of patient behavior immediately after exposure to a coercive measure and 24 h later. Subjective distress was examined using the Coercion Experience Scale at debriefing. Regression analyses were performed to compare these outcome variables across the four types of coercive interventions. RESULTS: Using univariate statistics, no significant differences in effectiveness and subjective distress were found between the groups, except that patients who were involuntarily medicated experienced significant less isolation during the measure than patients who underwent combined measures. However, when controlling for the effect of demographic and clinical characteristics, significant differences on subjective distress between the groups emerged: involuntary medication was experienced as the least distressing overall and least humiliating, caused less physical adverse effects and less sense of isolation. Combined coercive interventions, regardless of the type, caused significantly more physical adverse effects and feelings of isolation than individual interventions. CONCLUSIONS: In the absence of information on individual patient preferences, involuntary medication may be more justified than seclusion and mechanical restraint as a coercive intervention. Use of multiple interventions requires significant justification given their association with significant distress

    Characterization of thin MoO3 films formed by RF and DC-magnetron reactive sputtering for gas sensor applications

    Get PDF
    The present work discusses a technology f or deposition and characterization of thin molybdenum oxide (MoO x , MoO 3 ) films studied for gas sensor applications. T he samples were produced by reactive radio - frequency (RF) and direct c urrent (DC) magnetron sputtering. The composition and microstructure of the films were studied by XPS , XRD and Raman spectroscopy, the morphology , using high resolution SEM. T he research was focused on the sensing properties of the sputtered thin MoO 3 films. Highly sensitive gas sensor s were implemented by depositing films of various thicknesses on quartz resonators. Making use of the quartz crystal microbalance (QCM) method , the se sensors we re capable of detect ing chan ges in the molecular range. Prototype QCM structures with thin MoO 3 films were tested for sensitivity to NH 3 and NO 2 . E ven in as - deposited state and without heating the substrates, these films show ed good sensitivity . Moreover , no a dditional thermal treatment is necessary, which makes the production of such QCM gas sensor s simple and cost - effective, as it is fu lly compatible wit h the technology for producing t he initial resonator . Т he films are sensitive at room temperature and can reg ister concentrations as low as 50 ppm . The sorption is fully reversible , the films are stable and capable of long - term measuremen ts

    q-Analogue of Am1An1Amn1A_{m-1}\oplus A_{n-1}\subset A_{mn-1}

    Full text link
    A natural embedding Am1An1Amn1A_{m-1}\oplus A_{n-1}\subset A_{mn-1} for the corresponding quantum algebras is constructed through the appropriate comultiplication on the generators of each of the Am1A_{m-1} and An1A_{n-1} algebras. The above embedding is proved in their qq-boson realization by means of the isomorphism between the Aq\mathcal{A}_q^{-} (mn)nAq\sim {\otimes} ^n \mathcal{A}_q^{-}(m)mAq\sim {\otimes}^m\mathcal{A}_q^{-}(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse

    Isospin symmetry breaking in an algebraic pairing Sp(4) model

    Get PDF
    An exactly solvable sp(4) algebraic approach extends beyond the traditional isospin conserving nuclear interaction to bring forward effects of isospin symmetry breaking and isospin mixing resulting from a two-body nuclear interaction that includes proton-neutron (pn) and like-particle isovector pairing correlations plus significant isoscalar pn interactions. The model yields an estimate for the extent to which isobaric analog 0+ states in light and medium mass nuclei may mix with one another and reveals possible, but still extremely weak, non-analog beta-decay transitions.Comment: 8 pages, 2 figure

    A deep learning-based dirt detection computer vision system for floor-cleaning robots with improved data collection

    Get PDF
    Floor-cleaning robots are becoming increasingly more sophisticated over time and with the addition of digital cameras supported by a robust vision system they become more autonomous, both in terms of their navigation skills but also in their capabilities of analyzing the surrounding environment. This document proposes a vision system based on the YOLOv5 framework for detecting dirty spots on the floor. The purpose of such a vision system is to save energy and resources, since the cleaning system of the robot will be activated only when a dirty spot is detected and the quantity of resources will vary according to the dirty area. In this context, false positives are highly undesirable. On the other hand, false negatives will lead to a poor cleaning performance of the robot. For this reason, a synthetic data generator found in the literature was improved and adapted for this work to tackle the lack of real data in this area. This synthetic data generator allows for large datasets with numerous samples of floors and dirty spots. A novel approach in selecting floor images for the training dataset is proposed. In this approach, the floor is segmented from other objects in the image such that dirty spots are only generated on the floor and do not overlap those objects. This helps the models to distinguish between dirty spots and objects in the image, which reduces the number of false positives. Furthermore, a relevant dataset of the Automation and Control Institute (ACIN) was found to be partially labelled. Consequently, this dataset was annotated from scratch, tripling the number of labelled images and correcting some poor annotations from the original labels. Finally, this document shows the process of generating synthetic data which is used for training YOLOv5 models. These models were tested on a real dataset (ACIN) and the best model attained a mean average precision (mAP) of 0.874 for detecting solid dirt. These results further prove that our proposal is able to use synthetic data for the training step and effectively detect dirt on real data. According to our knowledge, there are no previous works reporting the use of YOLOv5 models in this application.publishe
    corecore