887 resultados para full-scale testing
Resumo:
The problem-Musculoskeletal (MSK) symptoms are common within primary care but some GPs are not comfortable managing these; waiting times for hospital appointments are a major cause of patients’ complaints. Current UK healthcare policies emphasise a need for more community-based management. We aimed to pilot an innovative general practice-based clinic to improve the management of MSK and Sport and Exercise Medicine (SEM) symptoms within general practice.
The approach-This project was conducted in an inner-city practice of approximately 9,000 patients and 5 GP partners. The practice commissioned a novel monthly 4-hour clinic staffed by one GP with a specialist interest in MSK and SEM conditions. Each patient was allocated a 20-minute appointment. All primary care staff within the practice could refer any patient for whom they considered hospital referral appropriate, with no specific exclusion criteria. Management plans included injection therapy, exercise prescription and onward referral. After three months (August-October 2014) numbers of consultations, sources of referral, reasons for referral and management outcomes were described; patient satisfaction was assessed by questionnaire, offered to 10 randomly selected patients by reception staff and self-completed by patients. Costs of the clinic were compared to current options.
Findings- All patients (14 males; 21 females; aged 35-77 years), were seen within four weeks of referral (one third of orthopaedic referrals in 2013 waited over 9 weeks for appointment). Most were referred from other GPs; some came from physiotherapy and podiatry. Shoulder problems were the most frequent reason for referral. The commonest management option was steroid injection, with most patients being given advice regarding exercise and analgesia; there were 3 onward referrals (2 physiotherapy; 1 rheumatology).
Comparing August-October data in 2014 and 2013, total, orthopaedic and rheumatology referrals were reduced by 147, 2 and 3, respectively; within the practice MSK presentations and physiotherapy and x-ray referrals were 60, 47 and 90 fewer, respectively.
The cost per attendance at the clinic was £61; initial orthopaedic-ICAT assessments cost £82 and a consultant appointment £213.
Satisfaction questionnaires were returned by all 10 selected participants and provided positive feedback, expressing preference for community-based, rather than hospital, management.
Consequence- Our pilot study indicates that this novel service model has potential for efficient and effective management of MSK and SEM complaints in primary care, reducing the need for hospital referral and the clinical burden on general practices. The innovation deserves further evaluation in a full-scale trial to determine its generalisability to other practice settings and populations.
Resumo:
This paper presents an analytical solution for the solid stresses in a silo with an internal tube. The research was conducted to support the design of a group of full scale silos with large inner concrete tubes. The silos were blasted and formed out of solid rock underground for storing iron ore pellets. Each of these silos is 40m in diameter and has a 10m diameter concrete tube with five levels of openings constructed at the centre of each rock silo. A large scale model was constructed to investigate the stress regime for the stored pellets and to evaluate the solids flow pattern and the loading on the concrete tube. This paper focuses on the development of an analytical solution for stresses in the iron ore pellets in the silo and the effect of the central tube on the stress regimes. The solution is verified using finite element analysis before being applied to analyse stresses in the solid in the full scale silo and the effect of the size of the tube.
Resumo:
Concrete cover separation is a common failure mode of reinforced concrete (RC) beams strengthened with a fibre-reinforced polymer (FRP) plate bonded to the tension face (FRP-plated RC beams). Plate-end FRP U-jackets have previously been explored as a mitigation measure to delay or suppress concrete cover separation, although its effectiveness needs further clarification. The paper presents the first systemic experimental study on the use of FRP U-jackets of different forms for mitigating the concrete cover separation failure. A total of ten full-scale FRP-plated RC beams were tested. The test results show that both the ultimate load and the ductility of the beams were enhanced by the U-jackets. Among the forms of U-jackets explored, those inclined at 45o are the most effective.
Resumo:
One of the challenges the tidal power industry faces, is the requirement of cost effective, reliable but highly accurate acquisition of flow data. Different methods are required , applications range over different spatial and temporal scales. This report assembles in the first sections, theoretical background information on acoustic Doppler Velocimetry and RADAR measurements. The use of existing expertise in field tests of marine vehicles is discussed next, followed by a discussion of issues relating to recreating field conditions in laboratory environments. The last three sections present practical applications of various methods performed in field conditions. While progress has been made over the last years, this overview highlights the challenges in full scale field measurements and knowledge gaps in the industry.
Resumo:
This paper presents the results of a full-scale site fire test performed on a cold-formed steel portal frame building with semi-rigid joints. The purpose of the study is to establish a performance-based approach for the design of such structures in fire boundary conditions. In the full-scale site fire test, the building collapsed asymmetrically at a temperature of 714°C. A non-linear elasto-plastic finite-element shell model is described and is validated against the results of the full-scale test. A parametric study is presented that highlights the importance of in-plane restraint from the side rails in preventing an outwards sway failure for both a single portal and full building geometry model. The study also demonstrates that the semi-rigidity of the joints should be taken into account in the design. The single portal and full building geometry models display a close match to site test results with failure at 682°C and 704°C, respectively. A design case is described in accordance with Steel Construction Institute design recommendations. The validated single portal model is tested with pinned bases, columns protected, realistic loading and rafters subject to symmetric uniform heating in accordance with the ISO 834 standard fire curve; failure occurs at 703°C.
Resumo:
Objective: To study the population distribution and longitudinal changes in anterior chamber angle width and its determinants among Chinese adults. Design: Prospective cohort, population-based study. Participants: Persons aged 35 years or more residing in Guangzhou, China, who had not previously undergone incisional or laser eye surgery. Methods: In December 2008 and December 2010, all subjects underwent automated keratometry, and a random 50% sample had anterior segment optical coherence tomography with measurement of angle-opening distance at 500 μm (AOD500), angle recess area (ARA), iris thickness at 750 μm (IT750), iris curvature, pupil diameter, corneal thickness, anterior chamber width (ACW), lens vault (LV), and lens thickness (LT) and measurement of axial length (AL) and anterior chamber depth (ACD) by partial coherence laser interferometry. Main Outcome Measures: Baseline and 2-year change in AOD500 and ARA in the right eye. Results: A total of 745 subjects were present for full biometric testing in both 2008 and 2010 (mean age at baseline, 52.2 years; standard deviation [SD], 11.5 years; 53.7% were female). Test completion rates in 2010 varied from 77.3% (AOD500: 576/745) to 100% (AL). Mean AOD500 decreased from 0.25 mm (SD, 0.13 mm) in 2008 to 0.21 mm (SD, 13 mm) in 2010 (difference, -0.04; 95% confidence interval [CI], -0.05 to -0.03). The ARA decreased from 21.5±3.73 10-2 mm2 to 21.0±3.64 10 -2 mm2 (difference, -0.46; 95% CI, -0.52 to -0.41). The decrease in both was most pronounced among younger subjects and those with baseline AOD500 in the widest quartile at baseline. The following baseline variables were significantly associated with a greater 2-year decrease in both AOD500 and ARA: deeper ACD, steeper iris curvature, smaller LV, greater ARA, and greater AOD500. By using simple regression models, we could explain 52% to 58% and 93% of variation in baseline AOD500 and ARA, respectively, but only 27% and 16% of variation in 2-year change in AOD500 and ARA, respectively. Conclusions: Younger persons and those with the least crowded anterior chambers at baseline have the largest 2-year decreases in AOD500 and ARA. The ability to predict change in angle width based on demographic and biometric factors is relatively poor, which may have implications for screening. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. © 2012 American Academy of Ophthalmology.
Resumo:
O comportamento cíclico das estruturas de betão armado é fortemente condicionado pelo mecanismo de aderência entre o betão e o aço. O escorregamento relativo entre os dois materiais, resultante da degradação progressiva da aderência em elementos solicitados por ações cíclicas, é uma causa frequente de danos graves e até do colapso de estruturas devido à ocorrência de sismos. Entre as estruturas existentes de betão armado que foram dimensionadas e construídas antes da entrada em vigor dos regulamentos sísmicos atuais, muitas foram construídas com armadura lisa, e portanto, possuem fracas propriedades de aderência. A informação disponível na literatura sobre o comportamento cíclico de elementos estruturais de betão armado com armadura lisa é reduzida e a influência das propriedades da aderência associadas a este tipo de armadura no comportamento cíclico das estruturas existentes não se encontra ainda devidamente estudada. O objectivo principal desta tese foi estudar a influência do escorregamento na resposta cíclica de elementos estruturais de betão armado com armadura lisa. Foram realizados ensaios cíclicos em elementos do tipo nó viga-pilar, construídos à escala real, representativos de ligações interiores em edifícios existentes sem pormenorização específica para resistir às ações sísmicas. Para comparação, foi realizado o ensaio de um nó construído com armadura nervurada. Foi ainda realizado o ensaio cíclico de uma viga de betão armado recolhida de uma estrutura antiga. Foram elaborados modelos numéricos não-lineares para simular a resposta dos elementos ensaiados, concentrando especial atenção no mecanismo do escorregamento. Os resultados obtidos no âmbito desta tese contribuem para o avanço do conhecimento sobre o comportamento cíclico de elementos estruturais de betão armado com armadura lisa. As análises numéricas realizadas comprovam a necessidade de incluir os efeitos do escorregamento na modelação numérica deste tipo de estruturas de forma a representar com rigor a sua resposta às ações cíclicas.
Resumo:
Uma das maiores causas de degradação dos revestimentos é a presença de sais solúveis, tanto nas zonas costeiras como nas zonas continentais. Estes sais podem ter origens distintas, tais como: humidade ascensional, nevoeiro salino, inundações ou ainda estarem presentes nos próprios materiais, como é o caso da utilização de areias mal lavadas. O local onde os sais cristalizam é dependente do tipo de transporte entre a alvenaria e o revestimento, assim como da severidade da envolvente ambiental (temperatura e humidade relativa). Com esta tese pretende-se desenvolver revestimentos de substituição compatíveis, eficazes e duráveis para alvenarias antigas sujeitas à ação severa da água (humidade ascensional através das fundações com elevada concentração de NaCl); desenvolver ensaios de envelhecimento acelerado baseados em ciclos de dissolução e cristalização que permitam simular a ação severa da água; perceber a influência de revestimentos com caraterísticas extremas de permeabilidade ao vapor de água aplicados nas duas faces do mesmo suporte (argamassas de cimento e resina versus argamassas de cal), e sujeitos à ação severa da água; perceber a influência de vários fatores, tais como : rasgos verticais contínuos executados no emboço e a utilização de hidrófugo no reboco no desempenho dos vários sistemas de revestimento desenvolvidos, quando sujeitos à ação severa da água;; utilizar a remoção eletrocinética de sais, em provetes simulando a influência da alvenaria e dos revestimentos, com o objetivo de reduzir a sua concentração de NaCl, para que no futuro possa ser aplicado de forma eficaz em paredes de edifícios antigos, enquanto ação de manutenção, e desta forma aumentar a durabilidade dos revestimentos. Para atingir os objetivos descritos, foram considerados: i) o desenvolvimento de provetes que permitam considerar os sistemas de revestimento desenvolvidos nesta tese e o suporte, e que simulem uma alvenaria revestida em ambas as faces, e com os quais seja possível a simulação da ação severa da água em laboratório e, ii) o desenvolvimento ciclos de dissolução e cristalização numa parede de grandes dimensões existente em laboratório, que permitam simular a ação severa da água em condições tão reais quanto possível. O objetivo final deste estudo é o desenvolvimento de um revestimento de substituição denominado “emboço ventilado” para paredes de edifícios antigos com revestimentos degradados devido à presença de humidade ascensional e sais solúveis. Pretende-se que este sistema de revestimento, composto por duas camadas de revestimento (camada base e reboco), seja compatível, durável e eficaz, e que funcione como um sistema de acumulação no qual os sais cristalizem na camada base do sistema de revestimento (executada com rasgos verticais) e não na alvenaria ou na camada exterior.
Resumo:
Sismos recentes comprovam a elevada vulnerabilidade dos edifícios existentes de betão armado. A resposta das estruturas aos sismos é fortemente condicionada pelas características da aderência aço-betão, que exibe degradação das propriedades iniciais quando sujeitas a carregamentos cíclicos e alternados. Este fenómeno é ainda mais gravoso para elementos com armadura lisa, predominantes na maioria das estruturas construídas até à década de 70 nos países do sul da Europa. A prática corrente de conceção, dimensionamento e pormenorização das estruturas antigas leva a que tenham características de comportamento e níveis de segurança associados não compatíveis com as exigências atuais. Os estudos realizados sobre o comportamento cíclico de elementos estruturais de betão armado com armadura lisa são ainda insuficientes para a completa caracterização deste tipo de elementos. Esta tese visou a caraterização da relação tensão de aderência versus escorregamento para elementos estruturais com armadura lisa e o estudo da resposta cíclica de pilares e nós viga-pilar de betão armado com armadura lisa. Foram realizados dez séries de ensaios de arrancamento (nove monotónicos e um cíclico) em provetes com varões lisos. Os resultados destes ensaios permitiram propor novas expressões empíricas para a estimativa dos parâmetros usados num modelo disponível na literatura para representação da relação tensão de aderência versus escorregamento. É ainda proposto um novo modelo monotónico para a relação tensão de aderência versus escorregamento que representa melhor a resposta após a resistência máxima de aderência. Uma campanha de ensaios unidirecionais em pilares e nós viga-pilar foi também realizada com o objetivo principal de caracterizar o comportamento cíclico deste tipo de elementos. No total foram realizados oito ensaios em pilares, sete ensaios em nós viga-pilar interiores e seis ensaios em nós viga-pilar exteriores representativos de estruturas antigas de betão armado com armadura lisa. Os resultados experimentais permitiram avaliar a influência do escorregamento e estudar o mecanismo de corte em nós e a evolução dos danos para elementos com armadura lisa. Com base nos resultados experimentais foi proposta uma adaptação na expressão do Eurocódigo 8-3 para o cálculo da capacidade última de rotação de elementos com armadura lisa. Foi também desenvolvido um estudo paramétrico, com diferentes estratégias de modelação não linear, para a simulação da resposta de pilares considerando o escorregamento da armadura lisa. Por último, foi proposto um novo modelo simplificado trilinear para o aço que contempla o efeito do escorregamento da armadura lisa.
Resumo:
This paper presents the experimental work carried out on a full scale concrete frame strengthened with Fibre Reinforced Polymer (FRP) composites. The frame was damaged, strengthened with FRP reinforcement and re-tested to assess the effectiveness of the strengthening technique. The natural frequencies of vibration, displacements, velocities and accelerations for both the unstrengthened and strengthened frame were recorded and compared.
Resumo:
An in situ experiment on a full-scale timber frame test building was carried out to study the hygrothermal performance of wood-hemp composite insulation in timber frame wall panels with and without a vapour barrier. The heat transfer properties and the likelihood of mould growth and condensation in the panels were compared. Step changes in the internal relative humidity were performed to explore the effects of high, normal and low internal moisture loads on the wall panels. No significant difference in the average equivalent thermal transmittance (U-values) between the panels with and without a vapour barrier was observed. The average equivalent U-values of the panels were close to the U-values calculated from the manufacturers’ declared thermal conductivity values of the insulation. The likelihood of condensation was higher at the interface of the wood-hemp insulation and the oriented strand board (OSB) in the panel without a vapour barrier. In terms of the parametric assessment of the mould germination potential, the relative humidity, the temperature and the exposure conditions in the insulation-OSB interfaces of the panel without a vapour barrier were found to be more favourable to the germination of mould spores. Nonetheless, when the insulations were dismantled, no mould was visually detected.
Resumo:
An in situ experiment in a full scale timber frame test building was carried out to compare the hygrothermal performance of Hemp and Stone Wool insulations of identical thermal conductivity. Hemp and Stone Wool insulations were installed in timber frame wall panels without vapour barrier. The comparison was made in terms of heat transfer properties, likelihood of mould growth and condensation. Step changes in internal relative humidity were performed to explore the effect of high and normal internal moisture load on the wall panels. No significant difference between the average equivalent thermal transmittance (U-values) of the panels incorporating Hemp and Stone Wool insulations was observed. The average equivalent U-values of the panels were closer to the calculated U-values of the panels based on the manufacturers’ declared thermal conductivity of Hemp and Stone Wool insulations. It was observed that the placement of heat flux sensor along the depth of the insulation had significant influence on the measured equivalent U-value of the panels during high internal moisture load. The frequency and likelihood of condensation was higher in the interface of Stone Wool and Oriented Strand Board (OSB). In terms of the parametric assessment of mould germination potential, relative humidity, temperature and exposure conditions in the insulation-OSB interfaces were found to be favourable to germination of mould spore. However, when the insulations were dismantled, no mould was visually detected.
Resumo:
Objective: To evaluate the feasibility of conducting a randomized controlled trial comparing group-based outpatient physiotherapy with usual care in patients following total knee replacement. Design: A feasibility study for a randomized controlled trial. Setting: One secondary-care hospital orthopaedic centre, Bristol, UK. Participants: A total of 46 participants undergoing primary total knee replacement. Interventions: The intervention group were offered six group-based exercise sessions after surgery. The usual care group received standard postoperative care. Participants were not blinded to group allocation. Outcome measures: Feasibility was assessed by recruitment, reasons for non-participation, attendance, and completion rates of study questionnaires that included the Lower Extremity Functional Scale and Knee Injury and Osteoarthritis Outcome Score. Results: Recruitment rate was 37%. Five patients withdrew or were no longer eligible to participate. Intervention attendance was high (73%) and 84% of group participants reported they were ‘very satisfied’ with the exercises. Return of study questionnaires at six months was lower in the usual care (75%) than in the intervention group (100%). Mean (standard deviation) Lower Extremity Functional Scale scores at six months were 45.0 (20.8) in the usual care and 57.8 (15.2) in the intervention groups. Conclusion: Recruitment and retention of participants in this feasibility study was good. Group-based physiotherapy was acceptable to participants. Questionnaire return rates were lower in the usual care group, but might be enhanced by telephone follow-up. The Lower Extremity Functional Scale had high responsiveness and completion rates. Using this outcome measure, 256 participants would be required in a full-scale randomized controlled trial.
Resumo:
A presente dissertação apresenta uma abordagem ao tema Fluência, com um desenvolvimento geral para quatro materiais: madeira, alumínio, betão e aço. No entanto, particularizou-se este estudo apenas para dois destes materiais, a madeira e o alumínio. A madeira é um material viscoelástico, logo fortemente influenciado quando submetido a uma ação constante (Fluência) sendo agravada com alterações do teor em água. Iniciou-se o estudo, com uma introdução aos objetivos principais e a revisão teórica do conhecimento da propriedade mecânica (Fluência). Efetuou-se o estudo inicial para os quatro materiais indicados. Posteriormente, fez-se avaliação do efeito mecânico sortivo durante 60 dias com sete ciclos, em provetes de dimensões 20 x 20 x 400 mm3 (escala 1:10) de madeira de Eucalyptus globulus Labill. Recorrendo ao levantamento de um conjunto de modelos numéricos, procedeu-se ao ajuste e extrapolação do comportamento, em Fluência, para distintos períodos de tempo (1, 10 e 50 anos). Os resultados obtidos demonstraram que a madeira de Eucalipto não apresenta um limite no seu comportamento em Fluência, logo instável para os 60 dias de duração de ensaio. Os diferentes modelos de Fluência (x6) apresentaram uma variabilidade crescente de resultados, de acordo com o aumento de extrapolação dos resultados. Para a espécie de madeira de Eucalipto constatou-se ainda, que o ajuste e extrapolação de deformação para 50 anos ultrapassaram os valores sugeridos pelo Eurocódigo 5. A última parte deste trabalho, incidiu sobre o desenvolvimento da metodologia do ensaio em flexão de 3 provetes de alumínio similares, cujas dimensões eram de 20 x 20 x 400mm3. O objetivo desta metodologia foi avaliar o seu comportamento em Fluência. Numa primeira fase, foi aplicada uma carga contante de 160 kN. E numa segunda fase, foi aplicada o dobro dessa carga sujeita adicionalmente a uma temperatura bastante superior à temperatura ambiente (a rondar os 50 oC). Conclusivamente verificou-se que o alumínio não apresenta deformação por Fluência, para as condições de ensaio apresentadas.
Resumo:
Enhanced biological phosphorus removal (EBPR) is the most economic and sustainable option used in wastewater treatment plants (WWTPs) for phosphorus removal. In this process it is important to control the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), since EBPR deterioration or failure can be related with the proliferation of GAOs over PAOs. This thesis is focused on the effect of operational conditions (volatile fatty acid (VFA) composition, dissolved oxygen (DO) concentration and organic carbon loading) on PAO and GAO metabolism. The knowledge about the effect of these operational conditions on EBPR metabolism is very important, since they represent key factors that impact WWTPs performance and sustainability. Substrate competition between the anaerobic uptake of acetate and propionate (the main VFAs present in WWTPs) was shown in this work to be a relevant factor affecting PAO metabolism, and a metabolic model was developed that successfully describes this effect. Interestingly, the aerobic metabolism of PAOs was not affected by different VFA compositions, since the aerobic kinetic parameters for phosphorus uptake, polyhydroxyalkanoates (PHAs) degradation and glycogen production were relatively independent of acetate or propionate concentration. This is very relevant for WWTPs, since it will simplify the calibration procedure for metabolic models, facilitating their use for full-scale systems. The DO concentration and aerobic hydraulic retention time (HRT) affected the PAO-GAO competition, where low DO levels or lower aerobic HRT was more favourable for PAOs than GAOs. Indeed, the oxygen affinity coefficient was significantly higher for GAOs than PAOs, showing that PAOs were far superior at scavenging for the often limited oxygen levels in WWTPs. The operation of WWTPs with low aeration is of high importance for full-scale systems, since it decreases the energetic costs and can potentially improve WWTP sustainability. Extended periods of low organic carbon load, which are the most common conditions that exist in full-scale WWTPs, also had an impact on PAO and GAO activity. GAOs exhibited a substantially higher biomass decay rate as compared to PAOs under these conditions, which revealed a higher survival capacity for PAOs, representing an advantage for PAOs in EBPR processes. This superior survival capacity of PAOs under conditions more closely resembling a full-scale environment was linked with their ability to maintain a residual level of PHA reserves for longer than GAOs, providing them with an effective energy source for aerobic maintenance processes. Overall, this work shows that each of these key operational conditions play an important role in the PAO-GAO competition and should be considered in WWTP models in order to improve EBPR processes.