85 research outputs found

    Is NP Aqr a new near-contact binary?

    Full text link
    We present radial velocities of the double-lined spectroscopic binary NP Aqr. The radial velocities and the optical light curves obtained by Hipparcos and ASAS-3 are analyzed separately. The masses of the primary and secondary components have been found to be 1.65±\pm0.09 and 0.99±\pm0.05 M⊙_{\odot}, respectively. The cross-correlation functions indicate triple peaks which show presence of a tertiary star. The spectroscopic properties of this additional component resemble to that of the primary star. The analysis of the light curves yielded that the more massive primary star fills its corresponding Roche lobe. The secondary component is at or near Roche lobe indicating a new β\beta Lyrae-type near-contact binary. The orbital inclination is about 40∘^{\circ} and, therefore, the observed light variations are produced only by the proximity effects. Due to the absence of eclipses, the effective temperature of the secondary star and the radii of the components could not be determined accurately. We conclude that NP Aqr is a non-eclipsing double-lined spectroscopic binary with a distance of about 134±\pm7 pc. The absolute parameters of the components are also compared with the evolutionary models. While the location of the primary star seems to be suitable with respect to its mass in the Hertzsprung-Russell diagram, the secondary component is located as if a star having a mass less than 0.6 M⊙_{\odot}. This discrepancy is originated from very low effective temperature determined only from the light curve produced by proximity effects. The distance to the third star appears to be very close to that of the close binary which indicates that it may be dynamically bounded to the binary.Comment: 14 pages, 5 figure, Accepted by New Astronom

    ANALYZING THE RETRIEVAL ACCURACY OF OPTICALLY ACTIVE WATER COMPONENTS FROM SATELLITE DATA UNDER VARYING IMAGE RESOLUTIONS

    Get PDF
    Water quality monitoring has a key role in maintaining a sustainable ecosystem and environmental health. To ensure consistent monitoring, remote sensing provides regular data acquisition with varying spatial resolutions. However, more accurate, and effective solutions can be achieved by integrating remote sensing data with in-situ measurements. This study investigates the integration of in-situ measurements with satellite data, which have different spectral and spatial resolutions, using linear and exponential regression models for four optically active components in the Gulf of Izmit. In this context, Sentinel-2 (S2) and PlanetScope SuperDove (PS) multispectral images, which were acquired on the same date, were used for the comparative analysis of the accurate mapping of chlorophyll-a (Chl-a), turbidity, Secchi disk depth (SDD) and total suspended matter (TSM) water quality parameters combined with simultaneously collected in-situ measurements. The models were evaluated using validation data, along with visual comparison, to assess their accuracy. The results indicate that, overall, exponential models provide more accurate results than linear models, except for the SDD parameter. Furthermore, models created with S2 data demonstrate better performance in retrieving water quality parameters for Chl-a, turbidity, and TSM, with R2 values of 0.71, 0.84, and 0.91, respectively. The linear model created with PS data stands out in the accurately mapping of SDD parameter. Nevertheless, the spatial distribution of these parameters using both satellite dataset exhibits a similar pattern throughout the gulf, which is under threat from significant terrestrial pollution sources, particularly in the eastern part

    Broadband absorption enhancement in an uncooled microbolometer infrared detector

    Get PDF
    This paper introduces a method for a broadband absorption enhancement in the LWIR range (8-12 μm), in single layer microbolometer pixels with 35 μm pitch. For the first time in the literature, this study introduces a very simple and low cost approach to enhance the absorption by embedding plasmonic structures at the same level as the already existing metallic layer of a microbolometer pixel. The metal layer comprises the electrode and the arm structures on the body. Even though the periodicity of the plasmonic structures is slightly disturbed by the placement of the electrodes and the connecting metal, the metal arms and the electrodes compensate for the lack of the periodicity contributing to the resonance by their coupling with the individual plasmonic resonators. Various plasmonic structures are designed with FDTD simulations. Individual, plasmonically modified microbolometer pixels are fabricated, and an increase in the average absorption due to surface plasmon excitation at Au/Si3N4 interfaces is observed. Plasmonic structures increase the average absorption from 78% to 82% and result in an overall enhancement of 5.1%. A good agreement between the simulation and the FTIR measurement results are obtained within the LWIR range. This work paves the way for integration of the plasmonic structures within conventional microbolometer devices for performance enhancement without introducing additional costs. © 2014 SPIE

    Printability, microstructure, and flow dynamics of phase-separated edible 3D inks

    Get PDF
    Personalizing the nutrition and sensorial attributes of 3D printed foods primarily requires various multiscale properties to be individually tailored. Herein, multiscale inks are produced by segregative phase separation, a candidate for further 3D inks texture control, of gellan gum (GG), and whey protein isolate (WPI). The inks microstructure, rheological properties, flow dynamics, their impact on printability, and properties-variables interactions are analyzed using experimental design and clustering. The gels are a GG matrix structured with WPI beads or fibers ranging from 100??m in diameter. A straightforward, six-step printability test determines that high-quality prints require increasing viscosity, which is obtained by reducing the size and length of the WPI beads. Also, flow dynamics and rheology models predict the shear stress and extrusion force, according to the print settings and food-inks fluid properties. The phase-separated inks enable printing at high speed (>25/50?mm/s) upon low extrusion forces (<50?N) and low shear stresses (<500?Pa), according to the calculations and model validation. These printability evaluation methodologies and fabrication of phase-separated inks are particularly interesting for 3D food printing, bioprinting, or biomaterials applications.Nanotechnology-based functional solutions project, funded by ERDF and CCDR-N, under the call Norte2020 (Ref. NORTE-01-0145-FEDER-000019) and Enhance Microalgae (High added-value industrial opportunities for microalgae in the Atlantic Area), funded by ERDF, under the Call Interreg Atlantic Area 2014–2020 (Ref. EAPA_338/2016)info:eu-repo/semantics/publishedVersio

    Tracing CNO exposed layers in the Algol-type binary system u Her

    Get PDF
    The chemical composition of stellar photospheres in mass-transferring binary systems is a precious diagnostic of the nucleosynthesis processes that occur deep within stars, and preserves information on the components’ history. The binary system u Her belongs to a group of hot Algols with both components being B stars. We have isolated the individual spectra of the two components by the technique of spectral disentangling of a new series of 43 high-resolution échelle spectra. Augmenting these with an analysis of the Hipparcos photometry of the system yields revised stellar quantities for the components of u Her. For the primary component (the mass-gaining star), we find MA = 7.88 ± 0.26 M⊙, RA = 4.93 ± 0.15 R⊙ and Teff, A = 21 600 ± 220 K. For the secondary (the mass-losing star) we find MB = 2.79 ± 0.12 M⊙, RB = 4.26 ± 0.06 R⊙ and Teff, B = 12 600 ± 550 K. A non-local thermodynamic equilibrium analysis of the primary star's atmosphere reveals deviations in the abundances of nitrogen and carbon from the standard cosmic abundance pattern in accord with theoretical expectations for CNO nucleosynthesis processing. From a grid of calculated evolutionary models the best match to the observed properties of the stars in u Her enabled tracing the initial properties and history of this binary system. We confirm that it has evolved according to case A mass transfer. A detailed abundance analysis of the primary star gives C/N = 0.9, which supports the evolutionary calculations and indicates strong mixing in the early evolution of the secondary component, which was originally the more massive of the two. The composition of the secondary component would be a further important constraint on the initial properties of u Her system, but requires spectra of a higher signal-to-noise ratio

    APPENDIX INTERPOSITION IN THE TREATMENT OF SEVERE POSTERIOR URETHRAL INJURIES

    No full text
    The aim of this study was to investigate the applicability of the Mitrofanoff principle in the treatment of severe posterior urethral injuries and determine the feasibility of this technique with its early and late postoperative results. A total of 27 New Zealand rabbits (12 male and 15 female) was used (mean weight 2,272 +/- 343 gm.). Using general anesthesia the proximal part of the posterior urethra was transected completely and a 1 cm, segment was excised. A 2 cm. segment of appendix with its intact vascular pedicle was meticulously mobilized and anastomosed to the proximal and distal site of the urethra. Excretory urograms, voiding cystourethrograms, urodynamic investigation and histopathological examination were performed postoperatively. The fertility of the male rabbits was examined in the late postoperative period as well. These results were compared with those of a control group. There was no problem concerning voiding patterns in the pedicled appendiceal flap group, Excretory urograms revealed a properly functioning urinary system. Voiding cystourethrograms showed a normal bladder capacity and voiding pattern, and an intact urethra. Urodynamic analysis was within normal limits except for a decrease in bladder volume. An intact urethral lumen without any strictures or fibrosis was demonstrated histopathologically. No calculus, mucus formation or urinary tract infection was observed in the late postoperative period. Fertility problems were noted in male rabbits, This animal experiment suggested that the pedicled appendiceal flap technique could be used for the treatment of severe forms of posterior urethral injuries

    FIRE WEATHER INDEX AND FOREST FIRE DANGER MAPPING: INSIGHTS FROM A CASE STUDY IN ANTALYA - MANAVGAT FOREST, TURKIYE

    No full text
    Forest fires in T&uuml;rkiye, like in other regions, have detrimental effects on wildlife habitats, water quality, air pollution, climate change, and the economy. These fires become particularly concerning during the dry summer months. In 2021, forest fires affected over 150 thousand hectares of land across the country, with the Manavgat district in Antalya province alone witnessing the burning of approximately 60 thousand hectares of forest area. This study aims to assess the applicability and suitability of Fire Weather Index (FWI) data derived from meteorological station data in the Antalya region, as well as EFFIS FWI data generated using satellite-based meteorological information, for fire danger mapping during the Manavgat forest fire that occurred between 28 July and 6 August 2021. Additionally, correlation analyses were performed between the two FWI datasets and other relevant variables, including the difference in Normalized Burn Ratio (dNBR), the difference in Land Surface Temperature (dLST), and Fire Radiative Power (FRP) data detected from MODIS and VIIRS satellites. The results of the correlation analysis indicated that the FWI values obtained using in-situ meteorology station data showed much higher correlations than FWI values obtained from EFFIS, with the highest correlation (73%) observed with dLST data. Consequently, the fire danger map was created using the in-situ meteorological data, given its stronger correlation. The results prominently revealed a widespread high-risk level across the entire Antalya province, with the Manavgat district classified into the "Extreme" and "Very Extreme" FWI classes, emphasizing the critical importance of utilizing in-situ meteorological data for precise fire danger assessments and proactive fire management strategies

    Angular momentum evolution of Algol binaries

    No full text
    WOS: 000241891700060We have compiled the well-determined absolute parameters of Algol-type binaries. The lists contain the parameters of 74 detached and 61 semidetached close binaries. The double-lined eclipsing binaries provide not only the most accurate determinations of stellar mass, radius and temperatures but also distance-independent luminosity for each of their individual components. The distributions of the primary and secondary masses of detached binaries (DBs) are similar, whilst the secondary masses of the semidetached binaries (SDBs) are mostly smaller than 2 M-circle dot with a peak in the M-2-bin (0.21-1.0). The components of the DBs are almost all located in the main-sequence band. On the contrary, the secondary components of the SDBs have larger radii and luminosity with respect to the same mass and the same effective temperature of main-sequence counterparts. They occupy a region of the Hertzsprung-Russell diagram between terminal-age main sequence and giants. Moreover, the total angular momenta and specific angular momenta are larger for the SDBs of orbital periods with P > 5 d than those of the shorter period ones. The specific angular momenta of SDBs with periods longer than 5 d are 65 per cent greater than that of the short period group with the same mass. The DBs and the SDBs with orbital periods longer and shorter than 5 d are separated into three groups in the J/M-5/3 - q diagram. The SDBs with mass ratios greater than 0.3 and P > 5 d have almost the same angular momentum to those of DBs. However, the SDBs with short periods have the smallest angular momentum even though they have the same mass ratios. This result reveals that angular momentum loss (AML) considerably affects the evolution of close binary systems. Recently, Chen, Li & Qian suggested that, in addition to magnetic braking, a circumbinary disc may play an important role in AML from Algol-type binaries. Their calculations indicated that the evolution of Algol-type binaries can be significantly affected by the circumbinary disc. Our results show that the evolution of close binaries begins as a DB and losing angular momentum, first via stellar wind and then magnetic braking plus circumbinary disc the period is shortened and orbit shrinks. Thereafter, the evolution of the system is accelerated and mass transfer rates are enhanced which result in a smaller mass ratios

    A well-differentiated giant liposarcoma originating from the buccal fat pad

    No full text
    Although liposarcoma is one of the most common soft-tissue sarcomas, facial localization is extremely rare, The buccal fat pad is an important anatomic structure located in the face that recently gained interest as a result of increasing research on facial anatomy, In this paper, we report a case of giant liposarcoma originating from the buccal fat pad, The precise localization of the tumor was determined preoperatively with computed tomography examination. The liposarcoma that invaded the body and the extensions of the buccal fat pad was resected completely, The pathological examination revealed a sclerosing, well-differentiated liposarcoma, which is known to be very rare in the head and neck region, Chemotherapy and radiotherapy were not necessary because of the favorable histological type of the tumor and the advanced age and poor general condition of the patient, Local recurrence and distant metastasis were not observed during the 1-year follow-up
    • …
    corecore