7,194 research outputs found

    Pyrolysis kinetics of hydrochars produced from brewer’s spent grains

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    The current market situation shows that large quantities of the brewer's spent grains (BSG)-the leftovers from the beer productions-are not fully utilized as cattle feed. The untapped BSG is a promising feedstock for cheap and environmentally friendly production of carbonaceous materials in thermochemical processes like hydrothermal carbonization (HTC) or pyrolysis. The use of a singular process results in the production of inappropriate material (HTC) or insufficient economic feasibility (pyrolysis), which hinders their application on a larger scale. The coupling of both processes can create synergies and allow the mentioned obstacles to be overcome. To investigate the possibility of coupling both processes, we analyzed the thermal degradation of raw BSG and BSG-derived hydrochars and assessed the solid material yield from the singular as well as the coupled processes. This publication reports the non-isothermal kinetic parameters of pyrolytic degradation of BSG and derived hydrochars produced in three different conditions (temperature-retention time). It also contains a summary of their pyrolytic char yield at four different temperatures. The obtained KAS (Kissinger-Akahira-Sunose) average activation energy was 285, 147, 170, and 188 kJ mol(-1) for BSG, HTC-180-4, HTC-220-2, and HTC-220-4, respectively. The pyrochar yield for all hydrochar cases was significantly higher than for BSG, and it increased with the severity of the HTC's conditions. The results reveal synergies resulting from coupling both processes, both in the yield and the reduction of the thermal load of the conversion process. According to these promising results, the coupling of both conversion processes can be beneficial. Nevertheless, drying and overall energy efficiency, as well as larger scale assessment, still need to be conducted to fully confirm the concept

    Rola patomorfologa w doborze terapii ukierunkowanej na receptor czynnika wzrostu naskórka (EGFR) u chorych na nowotwory

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    Targeted therapy has become an important modality of cancer treatment in the last decade. Drugs against EGFR and HER2 e.g. erlotinib, cetuximab or trastuzumab proved its role n therapy. They are managed as registered and recommended modalities of lung, alimentary tract and breast carcinoma. Significance of targeted treatment is a common effect of drug action and patient selection. Only a part of patients with tumors belonging to a specific histological type of cancer can benefit from targeted therapy. Determining predictive factor — informating on potential response to therapy — is essential for proper treatment in targeted therapy. Patients’ selection is accomplished by pathological methods with help of molecular biology techniques. Patient selection for targeted treatment and predictive factors evaluation criteria as well as establishing connections with traditional tumor characteristics (e.g. histological type, grade, stage) are continuously under research. Predictive factors are also investigated for traditional chemotherapeutics in recent years. Value of particular predictive factor depends on choice of evaluation method. Onkol. Prak. Klin. 2010; 6, 5: 228–235Leczenie celowane stało się w ostatniej dekadzie ważnym sposobem terapii chorych na raka. Potwierdzono skuteczność leków skierowanych przeciw receptorowi czynnika wzrostu naskórka (EGFR) i HER2, takich jak erlotynib, cetuksymab czy trastuzumab, a ich stosowanie obejmuje leczenie nowotworów płuca, przewodu pokarmowego i piersi. Wartość leków celowanych jest wypadkową działania leku i selekcji pacjentów do terapii. Leki celowane, jak wykazują wyniki badań, są skuteczne jedynie u części chorych na nowotwory danego typu histologicznego. Określenie czynnika predykcyjnego — informującego o potencjalnej odpowiedzi na leczenie — jest niezbędne w prawidłowym leczeniu celowanym. Selekcja pacjentów do tego typu terapii odbywa się w większości z wykorzystaniem metod patomorfologicznych wspomaganych technikami biologii molekularnej. Metody selekcji chorych i kryteria oceny czynników predykcyjnych oraz powiązanie ich z tradycyjnymi parametrami nowotworów (takimi jak typ histologiczny, stopień zaawansowania) są ciągle przedmiotem badań. W ostatnich latach, również dla chemioterapeutyków niezaliczanych do leków celowanych, próbuje się określić czynniki predykcyjne. Istotny wpływ na wartość poszczególnych czynników predykcyjnych ma wybór techniki ich określania. Onkol. Prak. Klin. 2010; 6, 5: 228–23

    NGC 1866: First Spectroscopic Detection of Fast Rotating Stars in a Young LMC Cluster

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    High-resolution spectroscopic observations were taken of 29 extended main sequence turn-off (eMSTO) stars in the young (\sim200 Myr) LMC cluster, NGC 1866 using the Michigan/Magellan Fiber System and MSpec spectrograph on the Magellan-Clay 6.5-m telescope. These spectra reveal the first direct detection of rapidly rotating stars whose presence has only been inferred from photometric studies. The eMSTO stars exhibit H-alpha emission (indicative of Be-star decretion disks), others have shallow broad H-alpha absorption (consistent with rotation \gtrsim 150 km s1^{-1}), or deep H-alpha core absorption signaling lower rotation velocities ( \lesssim 150 km s1^{-1} ). The spectra appear consistent with two populations of stars - one rapidly rotating, and the other, younger and slowly rotating.Comment: 9 pages, 4 figures, Accepted for publication in ApJ Letter

    Vertex Reconstruction Using a Single Layer Silicon Detector

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    Typical vertex finding algorithms use reconstructed tracks, registered in a multi-layer detector, which directly point to the common point of origin. A detector with a single layer of silicon sensors registers the passage of primary particles only in one place. Nevertheless, the information available from these hits can also be used to estimate the vertex position, when the geometrical properties of silicon sensors and the measured ionization energy losses of the particles are fully exploited. In this paper the algorithm used for this purpose in the PHOBOS experiment is described. The vertex reconstruction performance is studied using simulations and compared with results obtained from real data. The very large acceptance of a single-layered multiplicity detector permits vertex reconstruction for low multiplicity events where other methods, using small acceptance subdetectors, fail because of insufficient number of registered primary tracks.Comment: accepted for publication in Nucl. Instr. Meth.

    Integrated parameters of star clusters: A comparison of theory and observations

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    (Abridged) This paper presents integrated magnitude and colours for synthetic clusters. The integrated parameters have been obtained for the whole cluster population as well as for the main-sequence (MS) population of star clusters. We have also estimated observed integrated magnitudes and colours of MS population of galactic open clusters, LMC and SMC star clusters. It is found that the colour evolution of MS population of star clusters is not affected by the stochastic fluctuations, however these fluctuations significantly affect the colour evolution of the whole cluster population. The fluctuations are maximum in (VI)(V-I) colour in the age range 6.7 << log (age) << 7.5. Evolution of integrated colours of MS population of the clusters in the Milky Way, LMC and SMC, obtained in the present study are well explained by the present synthetic cluster model. The observed integrated (BV)(B-V) colours of MS population of LMC star clusters having age \geq 500 Myr seem to be distributed around Z=Z= 0.004 model, whereas (VI)(V-I) colours are found to be more bluer than those predicted by the Z=Z= 0.004 model. (VI)(V-I) vs (BV)(B-V) two-colour diagram for the MS population of the Milky Way star clusters shows a fair agreement between the observations and present model, however the diagrams for LMC and SMC clusters indicate that observed (VI)(V-I) colours are relatively bluer. Possible reasons for this anomaly have been discussed.Comment: 35 pages, 20 figs, accepted for publication in MNRA

    Application of Tracking and Data Relay Satellite (TDRS) Differenced One-Way Doppler (DOWD) Tracking Data for Orbit Determination and Station Acquisition Support of User Spacecraft Without TDRS Compatible Transponders

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    Many spacecraft are launched today with only an omni-directional (omni) antenna and do not have an onboard Tracking and Data Relay Satellite (TDRS) transponder that is capable of coherently returning a carrier signal through TDRS. Therefore, other means of tracking need to be explored and used to adequately acquire the spacecraft. Differenced One-Way Doppler (DOWD) tracking data are very useful in eliminating the problems associated with the instability of the onboard oscillators when using strictly one-way Doppler data. This paper investigates the TDRS DOWD tracking data received by the Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF) during the launch and early orbit phases for the the Interplanetary Physics Laboratory (WIND) and the National Oceanographic and Atmospheric Administration (NOAA)-J missions. In particular FDF personnel performed an investigation of the data residuals and made an assessment of the acquisition capabilities of DOWD-based solutions. Comparisons of DOWD solutions with existing data types were performed and analyzed in this study. The evaluation also includes atmospheric editing of the DOWD data and a study of the feasibility of solving for Doppler biases in an attempt to minimize error. Furthermore, by comparing the results from WIND and NOAA-J, an attempt is made to show the limitations involved in using DOWD data for the two different mission profiles. The techniques discussed in this paper benefit the launches of spacecraft that do not have TDRS transponders on board, particularly those launched into a low Earth orbit. The use of DOWD data is a valuable asset to missions which do not have a stable local oscillator to enable high-quality solutions from the one-way/return-link Doppler tracking data

    A Comprehensive Archival Search for Counterparts to Ultra-Compact High Velocity Clouds: Five Local Volume Dwarf Galaxies

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    We report five Local Volume dwarf galaxies (two of which are presented here for the first time) uncovered during a comprehensive archival search for optical counterparts to ultra-compact high velocity clouds (UCHVCs). The UCHVC population of HI clouds are thought to be candidate gas-rich, low mass halos at the edge of the Local Group and beyond, but no comprehensive search for stellar counterparts to these systems has been presented. Careful visual inspection of all publicly available optical and ultraviolet imaging at the position of the UCHVCs revealed six blue, diffuse counterparts with a morphology consistent with a faint dwarf galaxy beyond the Local Group. Optical spectroscopy of all six candidate dwarf counterparts show that five have an Hα\alpha-derived velocity consistent with the coincident HI cloud, confirming their association, the sixth diffuse counterpart is likely a background object. The size and luminosity of the UCHVC dwarfs is consistent with other known Local Volume dwarf irregular galaxies. The gas fraction (MHI/MstarM_{HI}/M_{star}) of the five dwarfs are generally consistent with that of dwarf irregular galaxies in the Local Volume, although ALFALFA-Dw1 (associated with ALFALFA UCHVC HVC274.68+74.70-123) has a very high MHI/MstarM_{HI}/M_{star}\sim40. Despite the heterogenous nature of our search, we demonstrate that the current dwarf companions to UCHVCs are at the edge of detectability due to their low surface brightness, and that deeper searches are likely to find more stellar systems. If more sensitive searches do not reveal further stellar counterparts to UCHVCs, then the dearth of such systems around the Local Group may be in conflict with Λ\LambdaCDM simulations.Comment: 18 pages, 4 tables, 4 figures, ApJ Accepte
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