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1.
Biomacromolecules ; 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39262301

RESUMO

Nanocellulose- and alginate-based hydrogels have been suggested as potential wound-healing materials, but their utilization is limited by the Food and Drug Administration (FDA) requirements regarding endotoxin levels. Cytotoxicity and the presence of endotoxin were assessed after gel sterilization using an autoclave and UV treatment. A new fingerprinting method was developed to characterize the compounds detected in cellulose nanocrystal (CNC)- and cellulose-nanofiber (CNF)-based hydrogels using both positive- and negative-ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectroscopy (ESI FT-ICR MS). These biobased hydrogels were used as scaffolds for the cultivation and growth of human dermal fibroblasts to test their biocompatibility. A resazurin-based assay was preferred over all other biocompatibility methodologies since it allowed for the evaluation of viability over time in the same sample without causing cell lysis. The CNF dispersion of 6 EU mL-1 was slightly above the limits, and it did not affect the cell viability, whereas CNC hydrogels induced a reduction of metabolic activity by the fibroblasts. The chemical structure of the detected endotoxins did not contain phosphates, but it encompassed hydrophobic sulfonate groups, requiring the development of new high-pressure sterilization methods for the use of cellulose hydrogels in medicine.

2.
Heliyon ; 9(10): e20516, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37876420

RESUMO

This research investigates the requirement for and relationship and implementation of a total productive maintenance (TPM) and Reliability Centred Maintenance (RCM) strategy within an Active Pharmaceutical Ingredient (API) Plant. This research aimed to study the tools and techniques of TPM and Reliability Engineering and then deploy a designed model to an API plant. A case study involving Design for Lean Six Sigma phases of Define, Measure, Analyse, Design, and Verify was utilised to build an API site TPM pilot program. Data was collected using interviews across Company 'X's local and Global Engineering teams. Process runtime, downtime and plant availability metrics were compiled and a new design for Total Productive Maintenance and Reliability was proposed and verified. A maintenance framework was designed to optimally incorporate Total Productive Maintenance, Reliability and Operational Excellence with an emphasis on Overall Equipment Efficiency (OEE) realizing a 33 % reduction in planned maintenance activities, a 70 % reduction in Corrective Maintenance, Cleaning for Maintenance was reduced by 50 %, the pilot maintenance area of the centrifuge has its OEE increased by 20 % and plant availability increased by two hundred and 6 h. This research highlights the importance of Total Productive Maintenance as a key component of an effective maintenance strategy and its potential to transform maintenance practices. Based on this research and results, TPM is recommended to be applied to any API manufacturing organization. A limitation of the study is that it is a single-site case study. The novelty of this research is based upon the emphasis on Reliability Engineering to remove non-value add Maintenance time from the manufacturing schedule. The Total Productive Maintenance & Reliability model designed and implemented in this research is unique in the literature and can be leveraged by engineering professionals and academics to understand the benefits of TPM.

3.
J Hazard Mater ; 439: 129696, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36104917

RESUMO

The aim of this study was to investigate the pyrolysis products of polyhydroxyalkanoates (PHAs), polyethylene terephthalate (PET), carbon fiber reinforced composite (CFRC), and block co-polymers (PS-b-P2VP and PS-b-P4VP). The studied PHA samples were produced at temperatures of 15 and 50 oC (PHA15 and PHA50), and commercially obtained from GlasPort Bio (PHAc). Initially, PHA samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) to determine the molecular weight, and structure of the polymers. Thermal techniques such as thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses were performed for PHA, CFRC, and block co-polymers to investigate the degradation temperature range and thermal stability of samples. Fast pyrolysis (500 oC, ∼102 °C s-1) experiments were conducted for all samples in a wire mesh reactor to investigate tar products and char yields. The tar compositions were investigated by gas chromatography-mass spectrometry (GC-MS), and statistical modeling was performed. The char yields of block co-polymers and PHA samples (<2 wt. %) were unequivocally less than that of the PET sample (~10.7 wt. %). All PHA compounds contained a large fraction of ethyl cyclopropane carboxylate (~ 38-58 %), whereas PAH15 and PHA50 additionally showed a large quantity of 2-butenoic acid (~8-12 %). The PHAc sample indicated the presence of considerably high amount of methyl ester (~15 %), butyl citrate (~12.9 %), and tributyl ester (~17 %). The compositional analyses of the liquid fraction of the PET and block co-polymers have shown carcinogenic and toxic properties. Pyrolysis removed matrices in the CRFC composites which is an indication of potential recovery of the original fibers.


Assuntos
Plásticos , Pirólise , Ésteres , Reciclagem , Alcatrões
4.
Artigo em Inglês | MEDLINE | ID: mdl-35954891

RESUMO

Assisted Human Reproduction (AHR) treatment is unregulated in Ireland, although it is practised there. Within Europe, Ireland is one of the only European countries without any form of AHR-specific regulation. This study aims to investigate the experiences and viewpoints of Irish women undergoing AHR treatments and establish if the lack of legislation is affecting these experiences. A quantitative survey was carried out on women undergoing AHR treatment in Irish clinics. Patients highlighted a lack of information in terms of end-to-end care and poor information around treatments and success rates. Key issues highlighted included unanticipated high treatment costs and add-on treatment costs, lack of financial support from the government, no redress process in the event of dissatisfaction, and generally an overall feeling of a lack of support both from the AHR clinics and the Irish government. This study offers a real-time view of the Irish AHR system from the patient's experience of AHR and under the lens of the lack of a legislative system. In early 2022, the Irish government announced that it would adopt its bill around AHR treatment and that subsidies for AHR treatment are to come into effect, which will alleviate some financial pressures on patients. Further studies of the legislation carried out post implementation will provide more information about the impact of having a legislated AHR process on the patients.


Assuntos
Reprodução , Europa (Continente) , Feminino , Humanos , Irlanda
5.
Biomacromolecules ; 23(6): 2512-2521, 2022 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-35506692

RESUMO

Rising global demand for biodegradable materials and green sources of energy has brought attention to lignin. Herein, we report a method for manufacturing standalone lignin membranes without additives for the first time to date. We demonstrate a scalable method for macroporous (∼100 to 200 nm pores) lignin membrane production using four different organosolv lignin materials under a humid environment (>50% relative humidity) at ambient temperatures (∼20 °C). A range of different thicknesses is reported with densely porous films observed to form if the membrane thickness is below 100 nm. The fabricated membranes were readily used as a template for Ni2+ incorporation to produce a nickel oxide membrane after UV/ozone treatment. The resultant mask was etched via an inductively coupled plasma reactive ion etch process, forming a silicon membrane and as a result yielding black silicon (BSi) with a pore depth of >1 µm after 3 min with reflectance <3% in the visible light region. We anticipate that our lignin membrane methodology can be readily applied to various processes ranging from catalysis to sensing and adapted to large-scale manufacturing.


Assuntos
Lignina , Silício , Catálise , Porosidade , Temperatura
6.
Energy Fuels ; 35(6): 4966-4978, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-34276128

RESUMO

Solid-fuel stoves are at the heart of many homes not only in developing nations, but also in developed regions where there is significant deployment of such heating appliances. They are often operated inefficiently and in association with high emission fuels like wood. This leads to disproportionate air pollution contributions. Despite the proliferation of these appliances, an understanding of particulate matter (PM) emissions from these sources remains relatively low. Emissions from five solid fuels are quantified using a "conventional" and an Ecodesign stove. PM measurements are obtained using both "hot filter" sampling of the raw flue gas, and sampling of cooled, diluted flue gas using an Aerosol Chemical Speciation Monitor and AE33 aethalometer. PM emissions factors (EF) derived from diluted flue gas incorporate light condensable organic compounds; hence they are generally higher than those obtained with "hot filter" sampling, which do not. Overall, the PM EFs ranged from 0.2 to 108.2 g GJ-1 for solid fuels. The PM EF determined for a solid fuel depends strongly on the measurement method employed and on user behavior, and less strongly on secondary air supply and stove type. Kerosene-based firelighters were found to make a disproportionately high contribution to PM emissions. Organic aerosol dominated PM composition for all fuels, constituting 50-65% of PM from bituminous and low-smoke ovoids, and 85-95% from torrefied olive stone (TOS) briquettes, sod peat, and wood logs. Torrefied biomass and low-smoke ovoids were found to yield the lowest PM emissions. Substituting these fuels for smoky coal, peat, and wood could reduce PM2.5 emissions by approximately 63%.

7.
J Hazard Mater ; 365: 846-856, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30481735

RESUMO

This study aims to demonstrate a novel method for removing toxic chemicals using soot produced from wood and herbaceous biomass pyrolyzed in a drop tube reactor and tire pyrolytic carbon black. The influence of ash content, nanostructure, particle size, and porosity on the filter efficiency of steam activated carbon materials was studied. It has been shown for the first time that steam activated soot and carbon black can remove phenol and chloride with filter efficiencies as high as 95%. The correlation of filter efficiency to material properties showed that the presence of alkali and steam activation time were the key parameters affecting filter efficiencies. This study shows that steam activated biomass soot and tire carbon black are promising alternatives for the cleaning of wastewater.


Assuntos
Biomassa , Cloro/isolamento & purificação , Fenol/isolamento & purificação , Fuligem/química , Vapor , Águas Residuárias/química
8.
Chempluschem ; 83(8): 780-786, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31950668

RESUMO

Pyrolysis is a promising way to convert biomass into fuels and chemicals. This reaction is complex and inevitably involves a cascade of radical reactions that lead to char formation, in which some radicals become trapped and stabilized. Their nature is difficult to characterize, and in this respect computational chemistry can be a strong supplementary tool to electron spin resonance spectroscopy and other experimental methods. Here biomass char radicals and oxidation reactivity are studied experimentally, and density functional theory is used to predict the thermodynamic stability and g-values of carbon- and oxygen-centered radicals of polyaromatic char models including defect structures. Hydroxylated and especially certain dihydroxylated structures provide exceptional stabilization of oxygen-centered radicals. Hydrogen bonding plays a crucial role, and it is proposed that hydrogen atom transfer couples radical localizations. This is a new proposal on the structural requirements for stabilization of char radicals, which impacts our understanding of pyrolysis mechanisms and char reactivity.

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