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1.
Med Teach ; 45(10): 1071-1084, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-36708606

RESUMO

Selection is the first assessment of medical education and training. Medical schools must select from a pool of academically successful applicants and ensure that the way in which they choose future clinicians is robust, defensible, fair to all who apply and cost-effective. However, there is no comprehensive and evidence-informed guide to help those tasked with setting up or rejuvenating their local selection process. To address this gap, our guide draws on the latest research, international case studies and consideration of common dilemmas to provide practical guidance for designing, implementing and evaluating an effective medical school selection system. We draw on a model from the field of instructional design to frame the many different activities involved in doing so: the ADDIE model. ADDIE provides a systematic framework of Analysis (of the outcomes to be achieved by the selection process, and the barriers and facilitators to achieving these), Design (what tools and content are needed so the goals of selection are achieved), Development (what materials and resources are needed and available), Implementation (plan [including piloting], do study and adjust) and Evaluation (quality assurance is embedded throughout but the last step involves extensive evaluation of the entire process and its outcomes).HIGHLIGHTSRobust, defensible and fair selection into medical school is essential. This guide systematically covers the processes required to achieve this, from needs analysis through design, development and implementation, to evaluation of the success of a selection process.


Assuntos
Educação Médica , Faculdades de Medicina , Humanos
2.
Bioresour Technol ; 396: 130417, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38316229

RESUMO

Global food waste emits substantial quantities of nitrogen to the environment (6.3 Mtons annually), chicken feather (CF) waste is a major contributor to this. Pyrolysis, in particular co-pyrolysis of nitrogen-rich and lignocellulosic waste streams is a promising strategy to improve the extent of pyrolytic nitrogen retention by incorporating nitrogen in its solid biochar structure. As such, this biochar can serve as a precursor for nitrogen-enriched activated carbons for application in supercapacitors. Therefore, this study investigates the co-pyrolysis of CF with macadamia nut shells (MNS) to create nitrogen-rich activated carbons. Co-pyrolysis increased nitrogen retention during pyrolysis from 9 % to 18 % compared to CF mono-pyrolysis, while the porosity was maintained. After removing undesirable inorganic impurities by dilute acid washing, this led to a specific capacitance of 21F/g using a scan rate of 20 mV/s. Finally, cycling stability tests demonstrated good stability with 73 % capacitance retention after 10 000 cycles.


Assuntos
Carvão Vegetal , Macadamia , Eliminação de Resíduos , Animais , Galinhas , Nitrogênio/química , Plumas , Alimentos , Pirólise , Eletrodos
3.
Waste Manag ; 168: 376-385, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37348380

RESUMO

Fourteen biochars from seven biomass sources were investigated on their long-term Cd2+ removal. The experiments consisted of a ten-day batch Cd2+ adsorption in a pH-buffered solution (pH = 6) to minimise pH effects. Insect frass, spent peat and chicken manure-derived biochars are promising Cd2+ adsorbents. Pyrolysis temperature was crucial for optimising Cd2+ removal by insect frass and spent peat-derived biochars. For these biochars, a pyrolysis temperature of 450 °C was optimal. In contrast, the Cd2+ removal by chicken manure biochars was independent of pyrolysis temperature. The Cd2+ removal by insect-frass and spent peat-derived biochars was associated with chemisorption on surface functionalities, while using chicken manure biochars was more associated with Cd2+ precipitation. The kinetics of Cd2+ removal over the course of ten days showed that insect frass biochar (450 °C) showed a gradual increase from 36 to 75 % Cd2+ removal, while chicken manure and spent peat-derived biochar (450 °C) already showed a higher Cd2+ removal (72 - 89 %) after day 1. This evidences that a long-term Cd2+ removal effect can be expected for some biochars. This should certainly be taken into consideration in future soil-based experiments.


Assuntos
Cádmio , Solo , Animais , Esterco , Carvão Vegetal , Adsorção , Galinhas , Concentração de Íons de Hidrogênio
4.
J Environ Manage ; 91(12): 2736-47, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20724061

RESUMO

The disposal problem associated with phytoextraction of farmland polluted with heavy metals by means of willow requires a biomass conversion technique which meets both ecological and economical needs. Combustion and gasification of willow require special and costly flue gas treatment to avoid re-emission of the metals in the atmosphere, whereas flash pyrolysis mainly results in the production of (almost) metal free bio-oil with a relatively high water content. Flash co-pyrolysis of biomass and waste of biopolymers synergistically improves the characteristics of the pyrolysis process: e.g. reduction of the water content of the bio-oil, more bio-oil and less char production and an increase of the HHV of the oil. This research paper investigates the economic consequences of the synergistic effects of flash co-pyrolysis of 1:1 w/w ratio blends of willow and different biopolymer waste streams via cost-benefit analysis and Monte Carlo simulations taking into account uncertainties. In all cases economic opportunities of flash co-pyrolysis of biomass with biopolymer waste are improved compared to flash pyrolysis of pure willow. Of all the biopolymers under investigation, polyhydroxybutyrate (PHB) is the most promising, followed by Eastar, Biopearls, potato starch, polylactic acid (PLA), corn starch and Solanyl in order of decreasing profits. Taking into account uncertainties, flash co-pyrolysis is expected to be cheaper than composting biopolymer waste streams, except for corn starch. If uncertainty increases, composting also becomes more interesting than flash co-pyrolysis for waste of Solanyl. If the investment expenditure is 15% higher in practice than estimated, the preference for flash co-pyrolysis compared to composting biopolymer waste becomes less clear. Only when the system of green current certificates is dismissed, composting clearly is a much cheaper processing technique for disposing of biopolymer waste.


Assuntos
Biocombustíveis/economia , Resíduos Perigosos , Salix , Gerenciamento de Resíduos/economia , Bélgica , Biodegradação Ambiental , Biomassa , Biopolímeros/economia , Metais Pesados , Método de Monte Carlo , Poluentes do Solo
5.
Bioresour Technol ; 318: 124083, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32916464

RESUMO

A comparative techno-economic assessment and Monte Carlo risk analysis is performed on large scale (3 tonne/h) biochar production plants for conventional (CPS) and microwave (MWP) pyrolysis using six different residue streams. Both plants are viable with minimum selling prices between € 436/tonne and € 863/tonne for CPS, and between € 564/tonne and € 979/tonne for MWP. The CPS is therefore more viable than MWP as it is a simpler and more established technology. However, a 20% biochar price increase due to higher biochar quality makes the MWP technology more viable. Nevertheless, the discounted payback period remains higher than this of CPS due to the increased CAPEX. Biochar price is the most important determinant of a biochar production plant's feasibility, motivating the need for economic and market research on biochar prices in function of biochar characteristics to reduce fluctuations in widely varying biochar prices.


Assuntos
Micro-Ondas , Pirólise , Carvão Vegetal , Rios
6.
Chemosphere ; 202: 569-575, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29597174

RESUMO

After nuclear disasters, radioactive cesium partitions to soils and surface water, where it decays slowly. Hexacyanoferrates (HCFs) have excellent cesium removal properties but their structure is typically powdery. Many carrier materials, such as biomass or magnetic particles, have been used to provide a suitable substrate for HCFs that can be used in filters. This research uses the sorption properties of activated carbon (AC) to incorporate Ni-HCF, resulting in good structural properties of the hybrid material. These HCF-modified ACs show drastically improved sorption properties towards Cs after one, two and three HCF impregnation cycles. The activated carbon from brewer's spent grain with one modification cycle removes more than 80% of 1 mg L-1 Cs in a sea water solution and more than 98% of 1 mg L-1 Cs from surface water at a low AC dosage (0.5 g L-1). Iron and nickel leaching is studied and found to be dependent on the type of modified AC used and the leaching solution. Iron leaching can be problematic in surface and seawater, whereas nickel leaching is especially pronounced in seawater.


Assuntos
Césio/análise , Carvão Vegetal/química , Ferrocianetos/química , Níquel/química , Água do Mar/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Adsorção
7.
Appl Radiat Isot ; 126: 296-299, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28109700

RESUMO

A measurement station dedicated for quantitative radiological characterisation of naturally occurring radionuclides in a metallurgical company and based on gamma-ray spectrometry was developed. The station is intended for performing quality control of final non-ferrous metal products and for radiological checks of incoming materials. A low-background point-contact HPGe-detector was used and the signal was split in two branches to enable collecting simultaneously spectra with high amplification (for gamma-ray energies below 250keV) and low amplification.

8.
Anal Bioanal Chem ; 355(5-6): 726-9, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15045355

RESUMO

IR spectra of carbon clusters C(n) (n>/=3) trapped in noble gas matrices (Ar and Kr) at temperatures of 13, 30 and 35 K are analyzed using algorithms based on digital filtering techniques and non-linear least-squares fitting. The spectral features at different temperatures and in different matrices are discussed. The majority of the resolved lines are assigned to C(n) cluster species based on data obtained via quantum chemical computations and from tunable laser IR spectrometry of C(n) species in the gas phase. A complete analysis of the IR spectra is available upon request.

9.
J Environ Radioact ; 127: 56-63, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24158046

RESUMO

The Euratom BSS requires that in the near future (2015) the building materials for application in dwellings or buildings such as offices or workshops are screened for NORM nuclides. The screening tool is the activity concentration index (ACI). Therefore it is expected that a large number of building materials will be screened for NORM and thus require ACI determination. Nowadays, the proposed standard for determination of building material ACI is a laboratory analyses technique with high purity germanium spectrometry and 21 days equilibrium delay. In this paper, the B-NORM method for determination of building material ACI is assessed as a faster method that can be performed on-site, alternative to the aforementioned standard method. The B-NORM method utilizes a LaBr3(Ce) scintillation probe to obtain the spectral data. Commercially available software was applied to comprehensively take into account the factors determining the counting efficiency. The ACI was determined by interpreting the gamma spectrum from (226)Ra and its progeny; (232)Th progeny and (40)K. In order to assess the accuracy of the B-NORM method, a large selection of samples was analyzed by a certified laboratory and the results were compared with the B-NORM results. The results obtained with the B-NORM method were in good correlation with the results obtained by the certified laboratory, indicating that the B-NORM method is an appropriate screening method to assess building material ACI. The B-NORM method was applied to analyze more than 120 building materials on the Belgian market. No building materials that exceed the proposed reference level of 1 mSv/year were encountered.


Assuntos
Materiais de Construção/análise , Monitoramento de Radiação/instrumentação , Monitoramento de Radiação/métodos , Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Bélgica , Limite de Detecção , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Tório/análise
10.
Water Res ; 46(8): 2783-94, 2012 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-22402272

RESUMO

Copper and zinc removal from water (pH = 5.0) using adsorbents produced from slow and fast pyrolysis of industrial sludge and industrial sludge mixed with a disposal filter cake (FC), post treated with HCl, is investigated in comparison with a commercial adsorbent F400. The results show that a pseudo-second order kinetics model is followed. The Langmuir-Freundlich isotherm model is found to fit the data best. The capacity for heavy metal removal of studied adsorbents is generally better than that of commercial F400. The dominant heavy metal removal mechanism is cation exchange. Higher heavy metal removal capacity is associated with fast pyrolysis adsorbents and sludge/FC derived adsorbents, due to enhanced cation exchange. Improvement of Zn(2+) removal via 1 N HCl post-treatment is only effective when exchangeable cations of the adsorbent are substituted with H(+) ions, which boost the cation exchange capacity. Increase of temperature also enhances metal removal capacity. Fast pyrolysis sludge-based adsorbents can be reused after several adsorption-desorption cycles.


Assuntos
Filtração , Esgotos/química , Temperatura , Purificação da Água/métodos , Adsorção , Cátions , Cobre/isolamento & purificação , Ácido Clorídrico/química , Troca Iônica , Cinética , Microscopia Eletrônica de Varredura , Porosidade , Espectrofotometria Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Zinco/isolamento & purificação
11.
Radiother Oncol ; 99(1): 94-6, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21397968

RESUMO

A measurement procedure based on alanine/electron paramagnetic resonance (EPR) dosimetry was implemented successfully providing simple, stable, and accurate dose-to-water (D(w)) measurements. The correspondence between alanine and ionization chamber measurements in reference conditions was excellent. Alanine/EMR dosimetry might be a valuable alternative to thermoluminescent (TLD) and ionization chamber based measuring procedures in radiotherapy audits.


Assuntos
Alanina , Espectroscopia de Ressonância de Spin Eletrônica , Radiometria/métodos , Bélgica , Humanos , Análise dos Mínimos Quadrados , Garantia da Qualidade dos Cuidados de Saúde , Doses de Radiação , Dosagem Radioterapêutica , Reprodutibilidade dos Testes
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