RESUMO
BACKGROUND: Coronaviruses, a group of highly transmissible and potentially pathogenic viruses, can be transmitted indirectly to humans via fomites. To date, no study has investigated their persistence on carpet fibers. Establishing persistence is essential before testing the efficacy of a disinfectant. METHODS: The persistence of BCoV and HCoV OC43 on polyethylene terephthalate (PET) and nylon carpet was first determined using infectivity and RT-qPCR assays. Then, the disinfectant efficacy of steam vapor was evaluated against both coronaviruses on nylon carpet. RESULTS: Immediately after inoculation of carpet coupons, 32.50% of BCoV and 3.87% of HCoV OC43 were recovered from PET carpet, compared to 34.86% of BCoV and 24.37% of HCoV OC43 recovered from nylon carpet. After incubation at room temperature for 1 h, BCoV and HCoV OC43 showed a 3.6 and > 2.8 log10 TCID50 reduction on PET carpet, and a 0.6 and 1.8 log10 TCID50 reduction on nylon carpet. Based on first-order decay kinetics, the whole gRNA of BCoV and HCoV OC43 were stable with k values of 1.19 and 0.67 h- 1 on PET carpet and 0.86 and 0.27 h- 1 on nylon carpet, respectively. A 15-s steam vapor treatment achieved a > 3.0 log10 TCID50 reduction of BCoV and > 3.2 log10 TCID50 reduction of HCoV OC43 on nylon carpet. CONCLUSION: BCoV was more resistant to desiccation on both carpet types than HCoV OC43. Both viruses lost infectivity quicker on PET carpet than on nylon carpet. Steam vapor inactivated both coronaviruses on nylon carpet within 15 s.
Assuntos
Desinfecção , Vapor , Desinfecção/métodos , Desinfetantes/farmacologia , Pisos e Cobertura de Pisos , Polietilenotereftalatos , Nylons/farmacologia , Humanos , Coronavirus/efeitos dos fármacos , Animais , Coronavirus Humano OC43/efeitos dos fármacos , Coronavirus Humano OC43/fisiologiaRESUMO
This study presents a novel biotechnological approach for creating water vapor-resistant cryogels with improved integrity. Rice straw cellulose was transformed into nanofibrils through TEMPO-mediated oxidation and high-pressure homogenization. The resulting cryogels remained firm even when immersed in aqueous media, whose pores were used by live cell to deposit polyhydroxyalkanoate (PHA) particles inside them. This novel method allowed the compatibilization of PHA within the cellulosic fibers. As a consequence, the water sorption capacity was decreased by up to 6 times having just 4 % of PHA compared to untreated cryogels, preserving the cryogel density and elasticity. Additionally, this technique can be adapted to various bacterial strains and PHA types, allowing for further optimization. It was demonstrated that the amount and type of PHA (medium chain length and small chain length-PHA) used affects the properties for the cryogels, especially the water vapor sorption behavior and the compressive strength. Compared to traditional coating methods, this cell-mediated approach not only allows to distribute PHA on the surface of the cryogel, but also ensures polymer penetration throughout the cryogel due to bacterial self-movement. This study opens doors for creating cryogels with tunable water vapor sorption and other additional functionalities through the use of specialized PHA variants.
Assuntos
Celulose , Criogéis , Oryza , Poli-Hidroxialcanoatos , Poli-Hidroxialcanoatos/química , Criogéis/química , Oryza/química , Celulose/química , Água/química , Vapor , Óxidos N-Cíclicos/química , Força CompressivaRESUMO
Adlay bran is known for its nutrient-rich profile and multifunctional properties, and steam explosion (SE) is an emerging physical modification technique. However, the specific effects of SE on the activity composition and antioxidant capacity of adlay bran soluble dietary fiber (SDF) during in vitro digestion, as well as its influence on gut microbiota during in vitro fermentation, remain inadequately understood. This paper reports the in vitro digestion and fermentation characteristics of soluble dietary fiber from adlay bran modified by SE (SE-SDF). Compared with the untreated samples (0-SDF), most of the phenolic compounds and antioxidant capacity were significantly increased in the SE-SDF digests. Additionally, SE was beneficial for adlay bran SDF to increase the content of acetic acid, propionic acid and total short-chain fatty acids (SCFAs) in fermentation broth during in vitro fermentation. SE-SDF could promote the growth of beneficial bacteria while inhibiting the proliferation of pathogenic microbes. Our research indicates that SE-SDF shows strong antioxidant properties after in vitro digestion and plays a pivotal role in regulating gut microbiota during in vitro fermentation, ultimately enhancing human intestinal health.
Assuntos
Antioxidantes , Coix , Fibras na Dieta , Digestão , Ácidos Graxos Voláteis , Fermentação , Microbioma Gastrointestinal , Vapor , Fibras na Dieta/metabolismo , Microbioma Gastrointestinal/fisiologia , Antioxidantes/metabolismo , Antioxidantes/análise , Ácidos Graxos Voláteis/metabolismo , Ácidos Graxos Voláteis/análise , Coix/química , Humanos , Propionatos/metabolismo , Manipulação de Alimentos/métodosRESUMO
Research on the content of polyphenolic compounds in fruits and vegetables, the extraction of bioactive compounds, and the study of their impact on the human body has received growing attention in recent years. This is due to the great interest in bioactive compounds and their health benefits, resulting in increased market demand for natural foods. Bioactive compounds from plants are generally categorized as natural antioxidants with health benefits such as anti-inflammatory, antioxidant, anti-diabetic, anti-carcinogenic, etc. Thermal processing has been used in the food sector for a long history. Implementing different thermal processing methods could be essential in retaining the quality of the natural antioxidant compounds in plant-based foods. A comprehensive review is presented on the effects of thermal blanching (i.e., hot water, steam, superheated steam impingement, ohmic and microwave blanching), pasteurization, and sterilization and drying technologies on natural antioxidants in fruits and vegetables.
Assuntos
Antioxidantes , Manipulação de Alimentos , Frutas , Temperatura Alta , Verduras , Antioxidantes/análise , Frutas/química , Verduras/química , Manipulação de Alimentos/métodos , Pasteurização , Polifenóis/análise , Vapor , Humanos , Esterilização/métodos , Micro-OndasRESUMO
In this work, an attempt has been made to develop a novel natural polysaccharide-based composite packaging biofilm prepared through a solution casting method. The biofilm is prepared from guar gum (GG) and agar-agar (AA) beeswax (BE). The incorporation of 20 % wt./wt.glycerol BE in the blended polymer GG/AA (50:50) (GG/AA/BE20 (50:50)) film shows a reduction in water solubility (66.67 %), water vapour permeability (69.28 %) and oxygen permeability (72.23 %). Moreover, GG/AA/BE20 (50:50) shows an increment in the tensile strength and elongation of a break by 48.32 % and 26.05 %, respectively, compared to pristine GG film. The scanning electron microscopy (SEM) image reveals defects-free smooth surfaces of the film. The Fourier transform-infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the strong hydrogen bonding between GG, AA, and BE. The biodegradable film shows 99 % degradation within 28 days when placed in the soil. The developed film plays a crucial role in extending the shelf life of cheese, effectively maintaining its moisture content, texture, colour, and pH over a span of up to two months from the point of packaging. These results suggest that GG/AA/BE20 (50:50) composite film is a promising packaging film for cheese preservation.
Assuntos
Ágar , Queijo , Embalagem de Alimentos , Galactanos , Mananas , Gomas Vegetais , Ceras , Gomas Vegetais/química , Galactanos/química , Mananas/química , Embalagem de Alimentos/métodos , Ceras/química , Ágar/química , Permeabilidade , Conservação de Alimentos/métodos , Vapor , Resistência à Tração , SolubilidadeRESUMO
The aim of this work was to investigate the effects of ultrasonic treatment during soaking of potatoes on the physicochemical properties of starches obtained after 16 weeks of germination. The ultrasonic treatment showed a direct correlation between sprout length and ultrasonic time. The protein content decreased from 0.63 to 0.38 % and the fat content decreased significantly from 0.31 to 0.01 % after germination. The amylose content changed depending on the ultrasonic treatment, and increased from 36.27 to 40.92 % after 16 weeks of germination, which was related to the amylopectin debranching and the duration of the ultrasonic treatment. X-ray diffraction showed that the nanocrystals with hexagonal structure were not affected by the germination and the duration of ultrasonic treatment. Scanning electron microscopy showed that the surface of the starch granules was not affected by the enzymatic treatment. The sprouted potato starch resulted in films with better tensile strength and lower water vapor permeability (WVP) compared to the native potato starch films. In addition, the films produced with ultrasound stimulated potato starch exhibited better properties (high strength and low permeability), which is desirable when it comes to controlling moisture exchange between a food product and the surrounding atmosphere.
Assuntos
Fenômenos Químicos , Filmes Comestíveis , Germinação , Solanum tuberosum , Amido , Solanum tuberosum/química , Amido/química , Permeabilidade , Ondas Ultrassônicas , Amilose/química , Vapor , Resistência à Tração , Difração de Raios XRESUMO
Attenuating the moisture sensitivity of hydrophilic protein/polysaccharide-based films without impairing other properties remains a challenge. Fatty acid dispersed in Pickering emulsion was proposed to overcome such issue. An increase in fatty acid chain length slightly reduced the water vapor permeability (WVP) of emulsion films. As the number of fatty acid double bonds increased from 0 to 1, the WVP of emulsion films was significantly decreased by 14.02% while mechanical properties were significantly enhanced. More hydrogen bonds and stronger electrostatic interactions in the presence of fatty acids were observed by molecular dynamics simulation. The weight loss of bananas coated with oleic acid-incorporated film-forming emulsion was 6.81% lower than that of uncoated group after 4 days, and the corresponding film was more effective to delay oil oxidation than the commercial polypropylene film, indicating that the film is a promising alternative to food coating and packaging material.
Assuntos
Alginatos , Ácidos Graxos , Embalagem de Alimentos , Musa , Oryza , Permeabilidade , Proteínas de Plantas , Água , Embalagem de Alimentos/instrumentação , Musa/química , Oryza/química , Água/química , Alginatos/química , Proteínas de Plantas/química , Ácidos Graxos/química , Conservação de Alimentos/métodos , Conservação de Alimentos/instrumentação , Vapor , Óleos de Plantas/química , Emulsões/químicaRESUMO
To mitigate environmental impacts in food preservation, the development of a multifunctional membrane for packaging is of importance. In this study, we have successfully fabricated a nanofibrous membrane using an eco-friendly electrospinning technique, comprising polyvinyl alcohol (PVA), chitosan (CS), and tannic acid (TA). The resulting nanofibrous membranes were crosslinked with glutaraldehyde (GA) and surface modified with ZnO. Our findings demonstrate that the crosslinking process enhances water resistance, reduces water vapor permeability, improves tensile strength (from 3 to 18 MPa), and enhances thermal stability (increasing decomposition temperature from 225 °C to 310 °C). Furthermore, the incorporation of TA and ZnO provides antioxidant properties to the membrane, effectively preventing food decomposition caused by UV-induced oxidation. Additionally, CS, TA, and ZnO synergistically exhibit a remarkable antibacterial effect with a bacteriostasis rate exceeding 99.9 %. The strawberry fresh-keeping experiment further confirms that our developed membrane significantly extends shelf life by up to 6 days. Moreover, cytotoxicity assays confirm the non-toxic nature of these membranes. The innovative significance of this study lies in proposing a robust GA-PVA/CS/TA@ZnO nanofibrous membrane with excellent mechanical properties, biocompatibility, and multiple functionalities including antibacterial, anti-ultraviolet, and anti-oxidation capabilities. It has tremendous potential for applications in active food packaging materials.
Assuntos
Quitosana , Embalagem de Alimentos , Conservação de Alimentos , Frutas , Membranas Artificiais , Álcool de Polivinil , Quitosana/química , Álcool de Polivinil/química , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Frutas/química , Antioxidantes/química , Antioxidantes/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Taninos/química , Resistência à Tração , Nanofibras/química , Permeabilidade , Vapor , Óxido de Zinco/química , Óxido de Zinco/farmacologia , Fragaria/químicaRESUMO
Fat greatly impacts the overall texture and flavor of pork belly. Twice-cooked pork bellies (TPB), typically boiled and sliced before "back to pot" being stir-fried, is a classic Sichuan cuisine among stir-fried dishes. In this study, the effects of substituting conventional pan-frying (PCV) with superheated steam (SHS) technology on the sensory, texture, microstructure and flavor of the fat layers were investigated. SHS was used as an alternative to boiling (120 °C for 15, 20, 25, and 30 min), and "back to pot" stir-frying was also by SHS. TPB precooked for 25 min (P25) with SHS performed better quality characteristics than PCV, with less collagen fiber disruption and lipid droplet area, resulting in a lower hardness and higher shear force. Besides, the low-oxygen environment of SHS retarded the lipid peroxidation, showing a significantly lower MDA content than PCV. Differently, PCV exhibited more grassy and fatty flavors, while P25 exhibited a unique aroma of fruity and creamy due to its higher UFA/SFA ratios in the pre-cooking stage. Overall, the sensory scores of P25 were comparable to those of PCV (with no significant difference), revealing that SHS is expected to be applied to the industrial production of stir-fried dishes.
Assuntos
Culinária , Carne de Porco , Vapor , Culinária/métodos , Temperatura Alta , Peroxidação de Lipídeos , Carne de Porco/análise , PaladarRESUMO
The Thar is the most densely populated desert in the world, which supports diverse ecosystems and human endeavours such as agriculture and socioeconomic activities. Water demand and supply in the Thar play an essential role in regulating the socioeconomic activities of the region. Inland water and precipitation aid the movement of water in the Thar Desert. Precipitation in the Thar is governed by the Indian Summer Monsoon (ISM), during which the winds distribute water vapour to regulate precipitation across the region. Therefore, we analyse the water vapour, its sources and its relation with precipitation using satellite measurements and reanalysis data in the Thar during ISM. Like other regions, a clear seasonal cycle of water vapour is observed in the Thar, with very high values (> 45 kg/m2) during ISM and low in winter (< 15 kg/m2). Evapotranspiration and moisture transport have significant effects on the amount of water vapour during ISM. There is a significant increase in water vapour in the troposphere, with high trends at the surface (0.032 g/kg/year) and small at the tropopause (0.00002 g/kg/year). A significant increase in column water vapour is also estimated in the Thar during ISM, with high trends in the eastern and southern areas, at about 0.15-0.35 kg/m2/year. The rise in water vapour in the Thar can be attributed to the increase in evapotranspiration (0.03-0.07 mm/day/year) and water vapour transport (> 0.5 kg/m/s/year) from the Arabian Sea and Indian Ocean. The rise in water vapour can lead to an increase in precipitation in the Thar, as it shows significant positive trends (0.05-0.1 mm/day/year) in the eastern areas during ISM. The increase in precipitation and water vapour in the arid Thar Desert can have significant implications for the regional environment and agriculture.
Assuntos
Clima Desértico , Estações do Ano , Vapor , Índia , Monitoramento Ambiental , Chuva , Atmosfera/químicaRESUMO
In the centuries following Christopher Columbus's 1492 voyage to the Americas, transoceanic travel opened unprecedented pathways in global pathogen circulation. Yet no biological transfer is a single, discrete event. We use mathematical modeling to quantify historical risk of shipborne pathogen introduction, exploring the respective contributions of journey time, ship size, population susceptibility, transmission intensity, density dependence, and pathogen biology. We contextualize our results using port arrivals data from San Francisco, 1850 to 1852, and from a selection of historically significant voyages, 1492 to 1918. We offer numerical estimates of introduction risk across historically realistic ranges of journey time and ship population size, and show that both steam travel and shipping regimes that involved frequent, large-scale movement of people substantially increased risk of transoceanic pathogen circulation.
Assuntos
Navios , Viagem , Humanos , Vapor , Modelos Teóricos , São Francisco/epidemiologia , História do Século XX , História do Século XIXRESUMO
Carboxymethylated derivatives of pullulan (PU) were synthesized and evaluated as coating for the postharvest preservation of blueberries. Carboxymethylpullulan was obtained by etherification reaction with the substitution degrees of 0.52, 0.34, and 0.26 for CMP1, CMP2, and CMP3 respectively. Infrared spectroscopy and nuclear magnetic resonance results showed characteristic signals of the carbonyl group belonging to the carboxymethyl group. Thermal analysis showed that CMP1, CMP2, and CMP3 derivatives presented thermal stability values of 209.91 C, 214.73 C, and 225.52 °C, respectively, and were lower with respect to PU with Td of 238.84 °C. Furthermore, an increase in the glass transition temperature due to carboxymethylation was determined. The chemical modification decreased the contact angle with respect to PU (71.34°) with values for CMP1, CMP2, and CMP3 of 39.89°, 53.72° and 60.61°, respectively. The carboxymethylation also increased the water vapor permeability and mechanical properties of the films. In addition, it was found that the CMP molecules affected the optical properties. The application of CMP-based coatings reduced the mass loss and ripening rate of blueberries compared to native pullulan, therefore, packaging from CMP molecules could be used as a coating capable of delaying ripening and extending the shelf life of fruits.
Assuntos
Embalagem de Alimentos , Glucanos , Glucanos/química , Mirtilos Azuis (Planta)/química , Conservação de Alimentos/métodos , Permeabilidade , Vapor , Frutas/químicaRESUMO
We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively.
Assuntos
Avena , Glucuronatos , Oligossacarídeos , Vapor , Catálise , Hidrólise , Oligossacarídeos/química , Avena/química , Glucuronatos/química , Polissacarídeos/químicaRESUMO
BACKGROUND: Enhancing the current breast pump sanitization method may improve maternal satisfaction and increase a mother's likelihood of providing human milk for their hospitalized infants in the Neonatal Intensive Care Unit (NICU). Other than Centers for Disease Control (CDC) data, there is lack of studies on sanitization practices. Currently, the only option in the hospital setting for breast pump equipment cleaning is a steam sanitization plastic bag. PURPOSE: Using the Q. Basin will increase participant satisfaction compared to the steam sanitization bag. METHODS: A multi-phased pilot study was conducted in our quaternary care NICU to test the Q. Basin, a novel design developed to wash, dry, and safely steam sanitize breast pump equipment compared to the standard steam bag. A bacterial study was conducted on breast pump equipment from 10 mothers by swabbing the equipment immediately at hour zero and 24 hours. Twenty NICU mothers concurrently evaluated their satisfaction via a 3-question survey comparing the Q. Basin and the steam sanitization plastic bag method. RESULTS: The results showed a 20% increase in satisfaction with Q. Basin compared to the steam bag method. IMPLICATIONS FOR PRACTICE AND RESEARCH: Data analysis from the satisfaction survey concludes that mothers pumping preferred the Q. Basin as a quicker, faster, and more environmentally friendly method for breast pump part sanitization. Additional safety and materials studies are required before using the Q. Basin in the clinical environment.
Assuntos
Extração de Leite , Unidades de Terapia Intensiva Neonatal , Humanos , Extração de Leite/instrumentação , Extração de Leite/métodos , Projetos Piloto , Recém-Nascido , Feminino , Desinfecção/métodos , Adulto , Satisfação do Paciente , Vapor , Contaminação de Equipamentos/prevenção & controle , Mães/psicologiaRESUMO
Solar energy interfacial evaporation represents a promising and sustainable approach with considerable potential for seawater desalination and wastewater treatment. Nonetheless, creating durable evaporators for continuous operation presents a challenge. Motivated by natural self-healing mechanisms, this study developed a novel 3D hybrid aero-hydrogel, which exhibited a self-healing efficiency of 89.4 % and an elongation at break post-healing of 637.7 %, featuring self-healing capabilities and continuous operation potential. Especially, the incorporation of hyperbranched water-soluble polymers (peach gum polysaccharide) endow the final solar water evaporators with a lower evaporation enthalpy of water, resulting in that the refined SVG3, with a notable water surface architecture and an expanded evaporation area, achieved a steam generation rate of 2.13 kg m-2 h-1 under 1 Sun. Notably, SVG2 achieved a high evaporation rate of 2.43 kg m-2 h-1 with the combined energy input of 1 Sun and 6 V, significantly surpassing the rate of 1.96 kg m-2 h-1 without voltage input. The results indicate that electrical energy significantly enhances and synergizes with SVG, facilitating continuous operation both day and night through the combined use of solar energy and electrical input. This study offers insightful perspectives for the strategic design of multifunctional hydrogels for solar water evaporation.
Assuntos
Hidrogéis , Gomas Vegetais , Polissacarídeos , Energia Solar , Gomas Vegetais/química , Hidrogéis/química , Polissacarídeos/química , Vapor , Prunus armeniaca/química , Água/químicaRESUMO
This study successfully prepared an edible packaging film that rapidly dissolves in water by utilizing a combination of κ-carrageenan, carboxymethyl starch, and gum ghatti. We investigated the influence of these three materials on the microstructure and physical properties of the film, as well as the impact of the film's dissolution on the stability of beverages. SEM, FTIR, and XRD analyses revealed that the κ-carrageenan, carboxymethyl starch, and gum ghatti primarily interacted through hydrogen bonding, resulting in a more uniform and dense film structure. Surface hydrophilicity and swelling tests indicated an increased presence of hydrophilic groups in the composite film. The inclusion of carboxymethyl starch and gum ghatti significantly improves the film's physical properties, resulting in a notable reduction in water solubility time, an increase in elongation at break from 19.5 % to 26.0 %, a rise in the contact angle from 49.1° to 67.0°, and a decrease in water vapor permeability from 7.5 × 10-10 to 6.2 × 10-10 g/m·s·Pa. Furthermore, coffee packaging bags made from this composite film dissolved entirely in hot water in just 40 s. Dissolving these bags significantly improved the stability of instant coffee, reducing centrifugal sedimentation from 3.8 % to 1.7 %. This study highlights the substantial potential of the κ-carrageenan/carboxymethyl starch/gum ghatti composite film as a packaging material for solid beverages.
Assuntos
Carragenina , Café , Filmes Comestíveis , Embalagem de Alimentos , Gomas Vegetais , Solubilidade , Amido , Água , Carragenina/química , Amido/química , Amido/análogos & derivados , Embalagem de Alimentos/métodos , Água/química , Café/química , Gomas Vegetais/química , Pós , Permeabilidade , Vapor , Interações Hidrofóbicas e HidrofílicasRESUMO
Previous research on Char reactions with gas phase compounds under micro-thermogravimetry systems shows that hydrogen inhibits heterogeneous char reactions. However, its impact on larger gasification systems with evolving hydrogen profiles remains largely unexplored. This study examines a macro-scale wood char bed to understand the influence of in situ evolving hydrogen on char reactions. When subjected to a specific steam flux, carbon conversion and pore morphology changes are mainly confined to the bed's upstream, with the downstream char retaining its original characteristics. Numerical investigations reveal over 75 % of species production and consumption occurs within the initial 20 % of bed height. Fourier-transform infrared spectroscopy confirms hydrogen-induced inhibition in downstream segments, showing a shift from C-OH to C-H bonds. Particle-scale analysis indicates significantly higher rates of hydrogen diffusion and adsorption compared to H2O, impeding downstream C+H2O reactions. Increased temperature, higher reactant concentrations, or reduced residence time can overcome this inhibition, enhancing conversion rates. These findings are critical for optimizing steam-to-biomass ratios in oxy-steam gasification systems for generating hydrogen-rich syngas.
Assuntos
Carbono , Hidrogênio , Água , Madeira , Hidrogênio/química , Madeira/química , Carbono/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Carvão Vegetal/química , Vapor , TemperaturaRESUMO
Sorption enhanced steam gasification of biomass (SESGB) presents a promising approach for producing high-purity H2 with potential for zero or negative carbon emissions. This study investigated the effects of gasification temperature, CaO to carbon in biomass molar ratio [CaO/C], and steam flow on the SESGB process, employing carbide slag (CS) and its modifications, CSSi2 (mass ratio of CS to SiO2 is 98:2) and CSCG5 (mass ratio of CS to coal gangue (CG) is 95:5), as CaO-based sorbents. The investigation included non-isothermal and isothermal gasification experiments and kinetic analyses using corn cob (CC) in a macro-weight thermogravimetric setup, alongside a fixed-bed pyrolysis-gasification system to assess operational parameter effects on gas product. The results suggested that CO2 capture by CaO reduced the mass loss during the main gasification as the [CaO/C] increased. The appropriate temperature for SESGB process should be selected between 550 and 700 °C at atmospheric pressure. The appropriate amount of sorbent or steam could facilitate the gasification reaction, but excessive addition led to adverse effects. Operational parameters influenced the apparent activation energy (Ea) by affecting various gasification reactions. For each test, Ea at the char gasification stage was significantly higher than that at the rapid pyrolysis stage. The addition of CS notably increased H2 concentration and yield, while sharply reducing CO2 levels. H2 concentration initially rose and then fell with greater steam flow, peaking at 76.11 vol% for a steam flow of 1.0 g/min. H2 yield peaked at 298 mL/g biomass with a steam flow of 1.5 g/min, a gasification temperature of 600 °C and a [CaO/C] of 1.0. Increasing gasification temperature remarkably boosted the H2 and CO2 yields. Optimal conditions for the SESGB using CS as a sorbent, determined via response surface methodology (RSM), include a gasification temperature of 666 °C, a [CaO/C] of 1.99, and a steam flow of 0.5 g/min, under which H2 and CO2 yields were 464 and 48 mL/g biomass, respectively. CSSi2 and CSCG5 demonstrated excellent cyclic H2 production stability, maintaining H2 yields around 440 mL/g biomass and low CO2 yields (â¼60 mL/g biomass) across five cycles. The study results offer new insights for the high-value utilization of agroforestry biomass and the reduction and resource utilization of industrial waste.
Assuntos
Biomassa , Hidrogênio , Vapor , Hidrogênio/química , Cinética , Carbono/química , Adsorção , TemperaturaRESUMO
Objective: To explore the method of preventing heat steam induced skin damage in robotic nipple-sparing mastectomy and immediate breast reconstruction (R-NSM-IBR) using Da Vinci Robots. Methods: A clinical data of 128 female patients with breast cancer, who were treated with R-NSM-IBR between September 2022 and December 2023 and met the selection criteria, was retrospectively analyzed. During robotic nipple-sparing mastectomy, the breasts were covered with gauze cooled by ice water to reduce skin temperature in 99 cases (group A) and were not treated in 29 cases (group B). There was no significant difference in the age, affected side, body mass index, pathological type of breast cancer, and constituent ratios of adjuvant chemotherapy and neoadjuvant chemotherapy between the two groups ( P>0.05). Intraoperative breast skin temperature, unilateral robotic nipple-sparing mastectomy time, and the incidence of complications of breast heat steam induced skin damage were recorded. Results: The time for unilateral robotic nipple-sparing mastectomy was (77.18±9.23) minutes in group A and (76.38±12.88) minutes in group B, with significant difference between the two groups ( P<0.05). The intraoperative breast skin temperature was significantly lower in group A than in group B [(25.61±0.91)â vs (33.38±1.14)â; P<0.05]. Seven cases of heat steam skin damage occurred during operation, including 2 cases (2.0%) in group A and 5 cases (17.2%) in group B, with a significant difference in incidence between the two groups ( P<0.05). Among them, 1 patient in group B had a vesication rupture and infection, which eventually led to the removal of the implant; the rest of the patients were treated with postoperative interventions for skin recovery. Conclusion: The use of breast covered with gauze cooled by ice water during R-NSM-IBR can effectively reduce the risk of heat steam induced skin damage.