Analysis of Sustainable Technologies for Acid Gas Removal

Acid gases, such as sulphur dioxide and hydrogen halides and – in a broad sense – carbon dioxide, are typical pollutants generated by combustion processes. Their removal by means of solid sorbents represent an efficient and cost-effective approach in dry acid gas treatment systems for waste incineration flue gas, while for CO2 capture the process is exploratively studied as a promising alternative to amine scrubbing. The present study addressed both aspects. In waste incineration flue gas cleaning, acid gas removal by sorbent injection is a well-established process. Nonetheless, a thorough understanding of the gas-solid reactions involved in the process has not been reached yet and, thus, the operation of dry treatment systems is still highly empirical. In the present study, the process was analysed using different levels of detail: from the microscopic level of a lab-scale experimental campaign and phenomenological description of the kinetic and mass transfer phenomena governing the gas-solid reaction to the macroscopic level of techno-economic and environmental assessment of alternative full-scale dry treatment systems. With respect to CO2 capture technologies, the process is still in the development stage and research is focused on the identification of highly-efficient sorbents. The present study analysed the enhancement of CO2 uptake potential of magnesium oxide, a promising sorbent for intermediate-temperature carbon capture, by means of coating with alkali metal molten salts. The joint analysis of gas-solid reaction for flue gas cleaning in two diverse contexts allowed the identification of common issues and of possible shared solutions

Integrating life cycle inventory and process design techniques for the early estimate of energy and material consumption data

Life cycle assessment (LCA) is a powerful tool to identify direct and indirect environmental burdens associated with products, processes and services. A critical phase of the LCA methodology is the collection of representative inventory data for the energy and material streams related to the production process. In the evaluation of new and emerging chemical processes, measured data are known only at laboratory scale and may have limited connection to the environmental footprint of the same process implemented at industrial scale. On the other hand, in the evaluation of processes already established at commercial scale, the availability of process data might be hampered by industrial confidentiality. In both cases, the integration of simple process design techniques in the LCA can contribute to overcome the lack of primary data, allowing a more correct quantification of the life cycle inventory. The present paper shows, through the review of case study examples, how simplified process design, modeling and simulation can support the LCA framework to provide a preliminary estimate of energy and material consumption data suitable for environmental assessment purposes. The discussed case studies illustrate the implementation of process design considerations to tackle availability issues of inventory data in different contexts. By evidencing the case-specific nature of the problem of preliminary conceptual process design, the study calls for a closer collaboration of process design experts and life cycle analysts in the green development of new products and processes

Assessment of Safety Barrier Performance in Environmentally Critical Facilities: Bridging Conventional Risk Assessment Techniques with Data-Driven Modelling

The failure of emission control systems in industrial processes undergoing emission regulations can cause severe harm to the environment. In this context, safety engineering principles can be applied to analyze process deviations and identify suitable safety barriers to mitigate harmful emissions during critical events. However, the selection, design, and assessment of proper safety barriers may be complex due to several contingencies such as the inability to perform extensive field tests on systems under strict emission regulations. In this study, an approach is proposed to couple conventional hazard identification techniques with a digital model of a flue gas treatment system to support the identification and performance assessment of safety barriers for emission control. Resilience analysis is used to evaluate the behavior of the most relevant safety barrier options, selected through a screening with conventional hazard identification tools. Barriers are simulated using the digital model of the system, gathering key information for their design and evaluation, and overcoming the limitations to field tests at the real plant. The methodology is illustrated with reference to acid gas removal in waste-to-energy facilities, a relevant example of an emission control system that is typically exposed to significant process deviations

Uncinate process deviation in patients with odontogenic sinusitis: a computed tomographic evaluation

The uncinate process of the ethmoidis is one of the anatomic boundaries of osti- omeatal complex. Its relationship with the maxillary sinus ostium makes it the key landmark for endoscopic sinus surgery. Many authors denied a direct role of the uncinate process in the development of sinonasal infections (1). Nevertheless, chronic sinonasal diseases are often accompanied by an uncinate process antero-medialization, most notably in presence of an odontogenic etiology. This study aimed to retrospectively analyze uncinate process anatomy on computed tomographic (CT) scans, defining the association between uncinate process inclination and sinonasal health status. Sinonasal CT examinations of 46 individuals were reviewed, comparing patients without clinical and radiographic signs of sinonasal diseases (Group I), and patients diagnosed with odontogenic sinusitis according to the criteria proposed by Felisati et al. (2)(Group II). Uncinate process inclination was calculated by Radiant Dicom Viewer software, as the angle between the straight line connecting the antero- superior and the postero-inferior part of uncinate process, and the axis of symmetry, passing through sphenoidal rostrum and perpendicular to bizygomatic line. For each patient three axial scans (the most cranial, median, the most caudal), in which uncinate process was clearly detectable, were selected and a mean value was computed. Descriptive statistics of uncinate process inclination were calculated separately in the two groups. In Group I the mean angle was13.18° ± 10.33°with confidence limits (CL) (99%) between 6.21° and 20.15°,in Group II the mean angle was 29.89°±9.56° with CL between 24.44° and 35.34°. From these preliminary results, a marked medial devia tion of uncinate process was identified in odontogenic sinusitis compared to healthy sites. Additional assessments are required to confirm the role of this anatomical varia- tion in the pathogenesis of odontogenic sinusitis

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM