A simplified method for referring the energy and overheating performance of window design

This paper describes a simplified dynamic thermal model which simulates the energy and overheating performance of windows. To calculate artificial energy use within a room, the model employs the average illuminance method, which takes into account the daylight energy impacting upon the room by the use of hourly climate data. This tool describes the main thermal performance ( heating, cooling and overheating risk) resulting proposed a design of window. The inputs are fewer and simpler than that are required by complicated simulation programmes. The method is suited for the use of architects and engineers at the strategic phase of design, when little is available.

Ranking of interventions to reduce dwelling overheating during heatwaves

Extreme weather events, including heatwaves, are predicted to increase in both frequency and severity over the coming decades. Low house building rates and a growing population mean there is a need to adapt existing dwellings. Research presented here uses dynamic thermal simulation to model the effect of passive heatwave mitigating interventions for UK dwellings. Interventions include a range of additions and modifications to solar shading, insulation and ventilation. Results are presented for typical end and mid terrace houses, with four orientations, two occupancy profiles and using weather data from the 2003 heatwave. Results show the effectiveness of interventions that reduce solar gains through the building fabric, such as external wall insulation and solar reflective coatings. Internal wall insulation is shown to be less effective and can increase the overheating problem in some cases. Control of solar gains through glazing, using shutters and fixed shading, are also effective, particularly for south, east and west-facing rooms. Results are also presented which demonstrate how it is possible to select combinations of interventions that both eliminate overheating and reduce space heating energy use. The cost of interventions is also considered in the final analysis.

Asymmetrical awnings : a way to increase daylight in buildings without increasing the overheating

Different shapes of asymmetric awnings for east and west windows are investigated mathematically as well as by measurement in a model. A box with 90 cm side and a 30x30 cm window was placed outdoor in overcast weather and the daylight factor was measured at the bottom of the box when the window was unshaded or equipped with different awnings. The average daylight factor in the box decreased from 4.6% for the unshaded window to 1.0% when a full awning was used. With “the best” asymmetrical awning, the average daylight factor was 80% larger than with the full awing. Using Dutch climate, calculation of the energy from direct radiation transmitted through the window during the cooling season showed that this was decreased from 100% as an annual mean for the unshaded window down 22% with a full awing. With “the best” asymmetrical awning, 26% of the energy was transmitted. Calculation of the indoor temperature in a hypothetical row house in Netherlands show that the use of either normal or asymmetrical awnings considerable decrease the indoor temperature during the hot season. Therefore the use of asymmetrical awnings for east or west faced windows considerable can increase the daylight in buildings, with almost no change in overheating, compared to if traditional awnings are used.

Embrittlement of case hardened steel chain link

Various steel chain links presented cracking during their manufacturing process, which includes induction case hardening and electrogalvanizing steps. Fractographic examination of the exposed crack surfaces revealed intergranular cracking with some areas featuring a thin layer of iron oxide, indicating that the cracking took place after the electrogalvanizing step. The location of the cracks coincided with the position of the deepest case hardened layer, suggesting the occurrence of localized overheating during the induction case hardening step. Inductive heating finite element analysis (COSMOS Designstar Software) confirmed that during the case hardening the austenitising temperature reached in the crack region values of approximately 1050 degrees C. The results indicated that intergranular cracking was caused by hydrogen embrittlement. (C) 2009 Elsevier Ltd. All rights reserved.

Estudo da delaminação em compósitos

As excelentes propriedades mecânicas, associadas ao seu baixo peso, fazem com que os materiais compósitos sejam atualmente dos mais interessantes da nossa sociedade tecnológica. A crescente utilização destes materiais e a excelência dos resultados daí provenientes faz com que estes materiais sejam utilizados em estruturas complexas de responsabilidade, pelo que a sua maquinagem se torna necessária de forma a possibilitar a ligação entre peças. O processo de furação é o mais frequente. O processo de maquinagem de compósitos terá como base os métodos convencionais utilizados nos materiais metálicos. O processo deverá, no entanto, ser convenientemente adaptado, quer a nível de parâmetros, quer a nível de ferramentas a utilizar. As características dos materiais compósitos são bastante particulares pelo que, quando são sujeitos a maquinagem poderão apresentar defeitos tais como delaminação, fissuras intralaminares, arrancamento de fibras ou dano por sobreaquecimento. Para a detecção destes danos, por vezes a inspeção visual não é suficiente, sendo necessário recorrer a processos específicos de análise de danos. Existem já, alguns estudos, cujo âmbito foi a obtenção de furos de qualidade em compósitos, com minimização do dano, não se podendo comparar ainda com a informação existente, no que se refere à maquinagem de materiais metálicos ou ligas metálicas. Desta forma, existe ainda um longo caminho a percorrer, de forma a que o grau de confiança na utilização destes materiais se aproxime aos materiais metálicos. Este trabalho experimental desenvolvido nesta tese assentou essencialmente na furação de placas laminadas e posterior análise dos danos provocados por esta operação. Foi dada especial atenção à medição da delaminação causada pela furação e à resistência mecânica do material após ser maquinado. Os materiais utilizados, para desenvolver este trabalho experimental, foram placas compósitas de carbono/epóxido com duas orientações de fibras diferentes: unidireccionais e em “cross-ply”. Não se conseguiu muita informação, junto do fornecedor, das suas características pelo que se levaram a cabo ensaios que permitiram determinar o seu módulo de elasticidade. Relativamente á sua resistência â tração, como já foi referido, a grande resistência oferecida pelo material, associada às limitações da máquina de ensaios não permitiu chegar a valores conclusivos. Foram usadas três geometrias de ferramenta diferentes: helicoidal, Brad e Step. Os materiais utilizados nas ferramentas, foram o aço rápido (HSS) e o carboneto de tungsténio para as brocas helicoidais de 118º de ângulo de ponta e apenas o carboneto de tungsténio para as brocas Brad e Step. As ferramentas em diamante não foram consideradas neste trabalho, pois, embora sejam reconhecidas as suas boas características para a maquinagem de compósitos, o seu elevado custo não justifica a sua escolha, pelo menos num trabalho académico, como é o caso. As vantagens e desvantagens de cada geometria ou material utilizado foram avaliadas, tanto no que diz respeito à delaminação como á resistência mecânica dos provetes ensaiados. Para a determinação dos valores de delaminação, foi usada a técnica de Raio X. Algum conhecimento já existente relativamente a este processo permitiu definir alguns parâmetros (por exemplo: tempo de exposição das placas ao liquido contrastante), que tornaram acessível o procedimento de obtenção de imagens das placas furadas. Importando estas imagens para um software de desenho (no caso – AutoCad), foi possível medir as áreas delaminadas e chegar a valores para o fator de delaminação de cada furo efetuado. Terminado este processo, todas as placas foram sujeitas a ensaios de esmagamento, de forma a avaliar a forma como os parâmetros de maquinagem afectaram a resistência mecânica do material. De forma resumida, são objetivos deste trabalho: - Caracterizar as condições de corte em materiais compósitos, mais especificamente em fibras de carbono reforçado com matriz epóxida (PRFC); - Caracterização dos danos típicos provocados pela furação destes materiais; - Desenvolvimento de análise não destrutiva (RX) para avaliação dos danos provocados pela furação; - Conhecer modelos existentes com base na mecânica da fratura linear elástica (LEFM); - Definição de conjunto de parâmetros ideais de maquinagem com o fim de minimizar os danos resultantes da mesma, tendo em conta os resultados provenientes dos ensaios de força, da análise não destrutiva e da comparação com modelos de danos existentes e conhecidos.

An investigation into the temperature distribution resulting from cutting of compact bone using a reciprocating bone saw

Surgical procedures such as osteotomy and hip replacement involve the cutting of bone with the aid of various manual and powered cutting instruments including manual and powered bone saws. The basic mechanics of bone sawing processes are consistent with most other material sawing processes such as for wood or metal. Frictional rubbing between the blade of the saw and the bone results in the generation of localised heating of the cut bone. Research studies have been carried out which consider the design of the bone saw which deals with specifics of the saw teeth geometry and research which examines the effect of drilling operations on heating of the bone has shown that elevated temperatures will occur from frictional overheating. This overheating in localised areas is known to have an impact on the rate of healing of the bone post operation and the sharpness life of the blade. The purpose of this study was to measure the temperature at three zones at fixed intervals of 3mm, 6mm, and 9mm away from the cutting zone. It should be noted that it was the first time that this measurement technique was used to measure the temperature gradient through the bone specimen thereby establishing the extent to which clinicians are experiencing thermal injury during sawing of bone while using a reciprocating saw. The effect of various cutting feed rate on temperature elevation was also investigated in this research. The results showed that there will be a region of bone at least 9mm either side of the cutting blade experiencing thermal injury as temperatures in this region exceeded the threshold temperature of 44°C for necrosis (cell death).

Analysis of energy management in GMIT

Energy management is the process of monitoring, controlling and conserving energy in a building or organisation. The main reasons for this are for cost purposes and benefit to the environment. Through various techniques and solutions for lighting, heating, office equipment, the building fabric etc along with a change in people’s attitudes there can be a substantial saving in the amount spent on energy. A good example o f energy waste in GMIT is the lighting situation in the library. All the lights are switched on all day on even in places where that is adequate daylighting, which is a big waste o f energy. Also the lights for book shelves are left on. Surely all these books won’t be searched for all at the one time. It would make much more sense to have local switches that the users can control when they are searching for a particular book. Heating controls for the older parts o f the college are badly needed. A room like 834 needs a TRV to prevent it from overheating as temperatures often reach the high twenties due to the heat from the radiators, computers, solar gains and heat from users o f the room. Also in the old part o f the college it is missing vital insulation, along with not being air tight due to the era when it was built. Pumped bonded bead insulation and sealant around services and gaps can greatly improve the thermal performance o f the building and help achieve a higher BER cert. GMIT should also look at the possibility o f installing a CHP plant to meet the base heating loads. It would meet the requirement o f running 4500 hours a year and would receive some financial support from the Accelerated Capital Allowance. I f people’s attitudes are changed through energy awareness campaigns and a few changes made for more energy efficient equipment, substantial savings can be made in the energy expenditure.

Monitorización de la temperatura de un CPD mediante una red de sensores inalámbricos

Con este proyecto se pretende que una organización sea más consciente del estado de sus máquinas y anticiparse a una situación de pérdida de información, parada de servicios o parada por sobrecalentamiento de servidores.

Uso de la hipotermia en el síndrome posparada cardíaca

Antecedentes: La parada cardiorrespiratoria es uno de los principalesproblemas sanitarios en los países desarrollados, además de por la mortalidadproducida, por las importantes repercusiones neurológicas posteriores quepresentan las personas que sobreviven. Hasta un 64% de los supervivientespuede presentar secuelas de gravedad, y tan solo un 1,4% queda exento dealgún tipo de alteración neurológica. Distintos ensayos clínicos, muestran quela hipotermia inducida ligera, es decir, el descenso controlado de latemperatura corporal mejora la supervivencia y los daños neurológicos en lospacientes adultos inconscientes tras una resucitación cardiopulmonar. Sinembargo, no está del todo claro cuáles son los pacientes más indicados pararecibir la terapia, la técnica de inducción ideal, la temperatura objetivo, suduración y la tasa idónea de recalentamiento.Objetivos: El objetivo del estudio es conocer la técnica de hipotermiaterapéutica como cuidado posresucitación tras sufrir una parada cardíaca.Metodología: Para ello, se realizó una búsqueda bibliográfica a través de lassiguientes bases de datos: CSIC, Medline PubMed, CINAHL, BibliotecaCochrane, Cuiden Plus, Dialnet, Scopus y ScienceDirect. Finalmente, seaceptaron 8 artículos que pertenecían a los criterios de inclusión: revisionessistemáticas, ensayos clínicos, revisiones bibliográficas y documentos deconsenso tras consejo de expertos, en español o inglés, publicados desde elaño 2005 hasta el año 2013 cuyos sujetos de estudio son adultos.Resultados: en la actualidad, se recomienda que los pacientes adultosinconscientes, con recuperación de la circulación espontánea tras una paradacardíaca extrahospitalaria, deben ser enfriados a 32-34ºC durante un periodode 12-24 horas cuando el ritmo inicial sea fibrilación ventricular. Se establecen4 periodos de tratamiento: inducción (desde el ingreso en la unidad hasta quese alcanzan los 33ºC), mantenimiento (desde el logro de los 33ºC hasta 24horas después), recalentamiento (12 horas de incremento de la temperatura,hasta alcanzar los 37ºC) y estabilización térmica (12 horas posteriores aalcanzar los 37ºC). Los métodos de inducción y mantenimiento de la hipotermiason diversos y se establecen dos grupos: técnicas invasivas y no invasivas.Palabras clave: hipotermia inducida, parada cardíaca, técnicas enfriamiento

Estudi sobre l'eficàcia dels mètodes de reescalfament in situ en el tractament de la hipotèrmia accidental en muntanya

En la última dècada, els esports de muntanya, en qualsevol de les seves modalitats, s’han vist incrementats en nombre de practicants. Aquest fet ha comportat un important augment d’incidència de la hipotèrmia accidental. La hipotèrmia accidental és defineix com un estat patològic caracteritzat per la disminució de la temperatura corporal central per sota dels 35ºC, com a resultat de la incapacitat de l’organisme per generar el calor necessari per garantir el manteniment de les funcions fisiològiques. A través d’aquest estudi es vol demostrar que l’actuació in situ, a través de certes mesures de reescalfament, de la víctima que pateix hipotèrmia, milloren la supervivència i les complicacions secundàries d’aquesta patologia, a més a més d’avaluar l’eficàcia d’aquestes tècniques. És a dir, volem demostrar l’efectivitat de l’aplicació terapèutica extrahospitalaria de les tècniques de reescalfament. Realitzarem un estudi quantitatiu observacional analític de caràcter prospectiu a la zona dels Alps francesos d’una mostra de 237 casos d’hipotèrmia en persones practicants d’esports de muntanya que reuneixin uns criteris d’inclusió i exclusió. Els professionals de rescat aplicaran les mesures de reescalfament prèviament pautades, per les quals hauran estat formats, i enregistraran en el full de recollida de dades tota la informació sobre les variables d’estudi. És un estudi on la intervenció principal es porta a terma al medi natural i que per tant les condicions climatològiques i medioambientals poden actuar com a gran limitador de l’estudi, cal afegir també com a limitació el fet que el participant no vulgui formar part de l’estudi o que el professional de rescat que ha de portar a terme el pla terapèutic no ho faci adequadament.

Reciclagem química de zeólitas comerciais desativadas

Pyro and hydrometallurgical processes were applied to the treatment of spent commercial zeolites (a molecular sieve and a ZSM-5 sample). Both catalysts were employed in pilot plant units. They were kept in their original shape, they were not regenerated and were not subjected neither to mechanical stress nor to overheating zones during their time on-stream. Two recycling processes were tested: (i) direct solubilization of samples in mixtures of HF + H2O2 (60 ºC, 1 h). Although silicon was solubilized, insoluble matter was found in both samples, particularly in the molecular sieve, due to its high amounts of alkaline and alkaline-earth metals; (ii) fusion with KHSO4 (5 h, 600 ºC) with KHSO4/zeolite mass ratio 6:1. After fusion the solid was solubilized in water (100 ºC), leaving silicon as SiO2 residue. In both processes, solubilized metals were isolated by conventional selective precipitation techniques. Analysis of final products by common analytical methods shows that metals present in the original catalysts were recovered with very high yields except when the molecular sieve was treated with HF + H2O2. This reactant mixture proved to be suitable for processing zeolites with a low alkaline and alkaline-earth metal content whereas fusion with KHSO4 appeared to be adequate for all types of zeolites.

Thermalhydraulic behavior of electrically heated rod during a critical heat flux transient

In nuclear reactors, the occurrence of critical heat flux leads to fuel rod overheating with clad fusion and radioactive products leakage. To predict the effects of such phenomenon, experiments are performed using electrically heated rods to simulate operational and accidental conditions of nuclear fuel rods. In the present work, it is performed a theoretical analysis of the drying and rewetting front propagation during a critical heat flux experiment, starting with the application of an electrical power step from steady state condition. After the occurrence of critical heat flux, the drying front propagation is predicted. After a few seconds, a power cut is considered and the rewetting front behavior is analytically observed. Studies performed with various values of coolant mass flow rate show that this variable has more influence on the drying front velocity than on the rewetting one.

Lessons learnt about water use, harvesting, recycling and drainage

This Information Paper is the third in a four-part series that looks at the lessons learnt from the BRE Innovation Park concerning compliance with the Code for Sustainable Homes published in November 2006. It focuses on water use, harvesting, recycling and drainage. The other parts deal with: building fabric; energy sources, overheating and ventilation; architecture, construction and sourcing.

The comfort, energy and health implications of London’s urban heat island

The urban heat island (UHI) is a well-known effect of urbanisation and is particularly important in world megacities. Overheating in such cities is expected to be exacerbated in the future as a result of further urban growth and climate change. Demonstrating and quantifying the impact of individual design interventions on the UHI is currently difficult using available software tools. The tools developed in the LUCID (‘The Development of a Local Urban Climate Model and its Application to the Intelligent Design of Cities’) research project will enable the related impacts to be better understood, quantified and addressed. This article summarises the relevant literature and reports on the ongoing work of the project.