Steam reforming of tar in hot syngas cleaning by different catalysts: Removal efficiency and coke layer characterization

Syngas produced by biomass and waste gasification processes must be ade-quately clean of tar compounds before being utilized in value-added applica-tions. Syngas cleaning by tar cracking at high temperatures is a promisingtechnique that can utilize different kinds of catalysts. However, their use islimited by the deposition of coke layers, which induces a masking phenome-non on the active surface, and, consequently, the rapid deactivation of the cat-alyst. This study addresses how the temperature (750 and 800 C) and thesteam concentration (0% and 7.5%) can affect the extent of water–gas andreforming reactions between steam and coke deposits. Two catalysts wereused: a market-available activated carbon and an iron-based alumina catalyst.The tests showed better performance of the Fe/γ-Al2O3catalyst. A massincrease of the bed was measured in tests with both the catalysts, which con-firms the deposition of the coke layer produced by tar dehydrogenation andcarbonization. Scanning electronic microscopy-energy-dispersive X-ray analy-sis (SEM-EDX) and Raman spectroscopy were utilized to investigate the natureof coke layers over the catalyst surface, with the aim of acquiring informationabout their reactivity towards the water gas reaction. SEM-EDX observationsindicate that the thickness of these carbon layers is less than 2μm. Ramanspectra suggest a negligible effect of the reaction temperature in the testedrange and, in particular, that the amorphous nature of coke layers deposited inthe presence of steam is relatively more graphitic than that obtained withoutsteam

A Gain Levelling Technique for On-Chip Antennas Based on Split-Ring Resonators

This paper introduces a gain enhancement technique for monolithically integrated antennas. Such devices can suffer from gain dips within their operating bandwidth due to standing waves arising in the die or caused by interactions with other on-chip components. In this work, it is shown how these effects can be significantly mitigated by parasitically coupling square Split Ring Resonators (SRR) to the fed antenna. The SRRs geometry and their coupling with the master antenna can be set in such a way that they create an additional resonance that cancels gain drops and improves impedance matching. The proposed configuration has been validated using a W-band monopole antenna in a standard $0.13~\mu \text{m}$ SiGe BiCMOS process. Thanks to the proposed approach, it was possible to compensate a gain drop of about 7 dB at about 85 GHz. As a result, the experimental assessment showed a maximum measured antenna gain of 1.61 dB at 81.5 GHz and an operating bandwidth from 77 to 87 GHz

Small leucine rich proteoglycans are differently distributed in normal and pathological endometrium

BACKGROUND: During the woman's fertile period, the non-pregnant uterus is subject to constant cyclic changes. The complex mechanisms that control the balance among proliferation, differentiation, cell death and the structural remodeling of the extracellular matrix can contribute to the benign or malignant endometrial pathological state. The small leucine-rich proteoglycans (SLRPs) are important components of cell surface and extracellular matrices. MATERIALS AND METHODS: Using immunohistochemistry, we showed that the distribution patterns of SLRPs were completely modified in the pathological compared to normal endometrium. RESULTS: The expression of SLRPs was low/absent in all endometrial pathologies examined compared to normal endometrium. We observed an increase of lumican from proliferative to secretory phase of the endometrium and a decrease of fibromodulin, biglycan and decorin. In menopause endometrial tissue, the level of expression of fibromodulin, biglycan, decorin and lumican dramatically decreased. CONCLUSION: The results revealed the prominence and importance of proteoglycans in the tissue architecture and extracellular matrix organization

Effective Neutralizing Antibody Response Against SARS-CoV-2 Virus and Its Omicron BA.1 Variant in Fully Vaccinated Hematological Patients

SARS-CoV-2 and its variants cause CoronaVIrus Disease 19 (COVID-19), a pandemic disease. Hematological malignancies increase susceptibility to severe COVID-19 due to immunosuppression. Anti-SARS-CoV-2 neutralizing antibodies protect against severe COVID-19. This retrospective real-life study aimed to evaluate seropositivity and neutralizing antibody rates against SARS-CoV-2 and its Omicron BA.1 variant in hematological patients. A total of 106 patients with different hematologic malignancies, who have mostly received three or more vaccine doses (73%), were included in this study. Serum was collected between May and June 2022. The primary endpoint was anti-SARS-CoV-2 antibody response against ancestral (wild type; wt) and Omicron BA.1 virus, defined as a neutralizing antibody titer ≥ 1:10. Adequate neutralizing antibody response was observed in 75 (71%) and 87 (82%) of patients for wt and Omicron BA.1 variants, respectively.However, patients with B-cell lymphoproliferative disorders and/or those treated with anti-CD20 monoclonal antibodies in the prior 12 months showed a lower seropositivity rate compared to other patients against both Omicron BA.1 variant (73% vs 91%; P = 0.02) and wt virus (64% vs 78%; P = 0.16). Our real-life experience confirmed that full vaccination against SARS-CoV-2 induces adequate neutralizing antibody protection for both the wt virus and Omicron BA.1 variants, even in hematological frail patients. However, protective measures should be maintained in hematological patients, especially those with B-cell lymphoproliferative diseases treated with anti-CD20 monoclonal antibodies, because these subjects could have a reduced neutralizing antibody production

Environmental performances of a modern waste-to-energy unit in the light of the 2019 BREF document

The study compares the environmental performances of a new-generation, large scale, combustion-based waste-to-energy unit, active since 2010, with those of different ‘‘virtual” units, defined in the light of the Best Available Techniques REFerence document (BREF) for Waste Incineration published by the European Community on December 2019. The average performances of these units have been evaluated in terms of air emissions, material consumptions and energy recovery, based on data related to 355 ‘‘existing” European waste incineration lines and those established for the future ‘‘new” plants. An attributional Life Cycle Assessment has been used to compare and quantify the environmental performances of the selected units, all equipped with a moving grate furnace and similar air pollution control systems. A sensitivity analysis quantifies how even more severe requests for emission and energy performances as well as the evolution of the European electricity mix until the year 2030 can affect the comparative assessment. The results indicate that the considered large scale waste-to-energy plant has good environmental performances, even in an electricity mix characterised by 45% of renewable sources. This allows an easy compliance with the Best Available Techniques Associated Emission Levels of the new waste incineration BREF document. Possible further improvements of its performances should be focused mainly on a further increase of the energy efficiency, provided that it is economically viable

The effect of steam concentration on hot syngas cleaning by activated carbons

Activated carbons are recognised as inexpensive, easily available, and efficient catalysts for tar cracking reactions at high temperatures. Their use in hot syngas cleaning is limited by the rapid deactivation resulting from the coke deposition, and the consequent masking phenomenon over the activated carbon surface. This study contributes to a better understanding of the problem and sheds light on possible solutions, by investigating how the temperature (750 ◦C–850 ◦C) and the steam concentration (0%–10%) can affect the extent of the water-gas and reforming reactions occurring between steam and the coke covering the catalyst surface. The activated carbons have been fully characterised before and after the tests utilizing naphthalene as a tar model compound, to study the evolution of their structure after long duration tests. Steam positively affects the naphthalene conversion efficiency, preserving the characteristics of the material. For example, at a temperature of 800 ◦C and a steam concentration of 7.5%, a naphthalene conversion of over 90% is achieved even after 7 h of testing. XRD and Raman spectroscopy analyses suggest that naphthalene cracking produces a coke layer that is more amorphous and, above all, more reactive towards the water gas reaction than the original activated carbon structure

Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study

Purpose: To evaluate preliminarily the safety and efficacy of customized photorefractive keratectomy (PRK) to correct ametropia and irregular astigmatism after penetrating keratoplasty (PK). Methods: This pilot study included five eyes of five patients with a mean spherical equivalent of −5.1 ± 1.46 D (range from −2.75 to −6.50 D). In all cases, ametropia and irregular astigmatism was corrected with topography-guided customized PRK. Ocular examinations with topographic analysis were performed preoperatively as well as at 1, 3 and 6 months after surgery. Results: All eyes gained postoperatively at least three Snellen lines of uncorrected visual acuity. Mean refractive spherical equivalent was 0.62 ± 0.63 D (range from −0.25 to −1.75 D) at 6 months postoperatively. Conclusion: Our pilot study suggests that customized PRK can be a safe and effective method for treating ametropia and irregular astigmatisms after PK. Future studies with larger samples and longer follow-ups should be performed to confirm these results

Co-gasification of plastics waste and biomass in a pilot scale fluidized bed reactor

Co-gasification tests were carried out in a pilot scale bubbling fluidized bed gasifier, large enough to exclude any scale-up effect, and able to treat up to 100 kg/h of plastics and biomass mixtures. It was operated under chemical and thermal steady-state, with equivalence ratios varying from 0.19 to 0.28, and plastics/biomass blending ratios from mono gasification of plastics to that of biomass. The results are reported in terms of main process performance parameters and axial profiles of syngas composition and reactor temperature. They indicate that plastics/biomass ratio and equivalence ratio remarkably affect the gasifier performances, even though the obtained syngas was always of rather good quality, with a low heating value between 7 and 10 MJ/m3N. The axial syngas compositions showed a monotonic reduction of carbon dioxide concentration (of about 20–30%) and a corresponding increase of hydrogen concentration (of about 90–110%), highlighting the key role of water gas shift, and steam and dry reforming reactions. The overall set of results provides information about the feasibility of co-gasification of plastics waste and biomass at a demonstration scale and supports the optimisation of design or operating criteria as well as the implementation of reliable numerical models of bubbling fluidized bed gasifiers