Analyse comparative de systèmes de construction industrialisés et leur applicabilité à une habitation multifamiliale verticale pour la classe moyenne à Recife (Brésil)

Depuis le début du XXe siècle, les architectes et ingénieurs anticipaient et idéalisaient l'industrialisation des bâtiments afin que les pièces des édifices puissent être conçues dans une usine de montage pour procéder ensuite à leur assemblage sur les chantiers. À l'heure actuelle, grâce à des chercheurs dédiés, cette industrialisation s’est concrétisée et de nombreux systèmes de construction industrialisés existent dans le monde entier, adaptés à des environnements particuliers. Dans ce contexte, cette étude a pour but d'analyser comparativement plusieurs systèmes à l’aide de certains critères d’évaluation, et de sélectionner, deux systèmes préfabriqués les mieux adaptés aux habitations multifamiliales verticales destinées à une population de classe moyenne aisée de la ville de Recife, au Brésil. La méthodologie s’inspire de l'approche systémique, utilisée par White (1970) et Richard (2002), les deux se caractérisant par une démarche évaluative. Ainsi avons-nous choisi comme étant les plus appropriés, parce que répondant bien au cadre général de Recife, le système préusiné en panneaux DESCON ainsi que celui de poutres et colonnes, commercialisé par les entreprises T&A et PDI, les deux en béton.

Design of maintenance structures for rural electrification with solar home systems. The case of the Moroccan program.

n decentralised rural electrification through solar home systems, private companies and promoting institutions are faced with the problem of deploying maintenance structures to operate and guarantee the service of the solar systems for long periods (ten years or more). The problems linked to decentralisation, such as the dispersion of dwellings, difficult access and maintenance needs, makes it an arduous task. This paper proposes an innovative design tool created ad hoc for photovoltaic rural electrification based on a real photovoltaic rural electrification program in Morocco as a special case study. The tool is developed from a mathematical model comprising a set of decision variables (location, transport, etc.) that must meet certain constraints and whose optimisation criterion is the minimum cost of the operation and maintenance activity assuming an established quality of service. The main output of the model is the overall cost of the maintenance structure. The best location for the local maintenance headquarters and warehouses in a given region is established, as are the number of maintenance technicians and vehicles required.

Aspects concerning the acoustical performance of school buildings in Portugal

Acoustic measurements were performed in eight schools of different levels of education (from kindergarten to college) located in Viseu – Portugal. The acoustic evaluation was made in order to analyze the most common problems that may condition the acoustic environment inside school building. The acoustics evaluation of school buildings was made by the measurement of: reverberation time in classrooms; sound insulation between classrooms and between classrooms and corridors; impact sound insulation of floors and airborne sound insulation of façade. The sound insulation of façade was made with all elements closed and with natural ventilation conditions (banners or windows tilt mode). It was found that most of the studied cases revealed disabled constructive aspects in relation to the acoustic requirements of school buildings compromising the quality of education.

Techno-economic analysis of three HVAC retrofitting options

Accounting for around 40% of the total final energy consumption, the building stock is an important area of focus on the way to reaching the energy goals set for the European Union. The relatively small share of new buildings makes renovation of existing buildings possibly the most feasible way of improving the overall energy performance of the building stock. This of course involves improvements on the climate shell, for example by additional insulation or change of window glazing, but also installation of new heating systems, to increase the energy efficiency and to fit the new heat load after renovation. In the choice of systems for heating, ventilation and air conditioning (HVAC), it is important to consider their performance for space heating as well as for domestic hot water (DHW), especially for a renovated house where the DHW share of the total heating consumption is larger. The present study treats the retrofitting of a generic single family house, which was defined as a reference building in a European energy renovation project. Three HVAC retrofitting options were compared from a techno-economic point of view: A) Air-to-water heat pump (AWHP) and mechanical ventilation with heat recovery (MVHR), B) Exhaust air heat pump (EAHP) with low-temperature ventilation radiators, and C) Gas boiler and ventilation with MVHR. The systems were simulated for houses with two levels of heating demand and four different locations: Stockholm, Gdansk, Stuttgart and London. They were then evaluated by means of life cycle cost (LCC) and primary energy consumption. Dynamic simulations were done in TRNSYS 17. In most cases, system C with gas boiler and MVHR was found to be the cheapest retrofitting option from a life cycle perspective. The advantage over the heat pump systems was particularly clear for a house in Germany, due to the large discrepancy between national prices of natural gas and electricity. In Sweden, where the price difference is much smaller, the heat pump systems had almost as low or even lower life cycle costs than the gas boiler system. Considering the limited availability of natural gas in Sweden, systems A and B would be the better options. From a primary energy point of view system A was the best option throughout, while system B often had the highest primary energy consumption. The limited capacity of the EAHP forced it to use more auxiliary heating than the other systems did, which lowered its COP. The AWHP managed the DHW load better due to a higher capacity, but had a lower COP than the EAHP in space heating mode. Systems A and C were notably favoured by the air heat recovery, which significantly reduced the heating demand. It was also seen that the DHW share of the total heating consumption was, as expected, larger for the house with the lower space heating demand. This confirms the supposition that it is important to include DHW in the study of HVAC systems for retrofitting.

Comparison of two HVAC renovation solutions : A case study

Within the aging building stock of Europe, there is great potential of saving energy through renovation and upgrading to modern standards, and to thereby approach the internationally set goals of lower energy use. This paper concerns the planned renovation of the building envelope and HVAC systems in a multi-family house in Ludwigsburg, Germany. Five systemic HVAC solutions were compared, with special focus on two systems: A) Balanced ventilation with HRC + Micro heat pump, and B) Forced exhaust ventilation + Heat pump with exhaust air HRC + Ventilation radiators. Given the predicted heating demand and ventilation rate of the house after renovation, the performance of the two systems was compared, alongside three common systems for reference. Calculations were made using TMF Energi, a tool developed by SP Technical Research Institute of Sweden.    Both systems A and B were found to have the lowest electrical energy use together with the ground source heat pump system for the assumed conditions. For other assumptions, including different climate and degree of insulation, some differences between these three systems were noted. Most significant is the increased electrical use of system B for higher heating loads due to limitations in the power available from the heat source, exhaust air, which is dependent on the ventilation rate.

South Carolina Housing Trust Fund Emergency Repair Manual

The emergency repair activity under the South Carolina Housing Trust Fund program is designed to assist very low‐income homeowners in making needed and necessary repairs to their owner‐occupied homes to eliminate life, health and safety issues to the occupant. This document explains emergency repair activity guidelines, eligibility requirements for properties, rehabilitation construction guidelines and payments.

INDOOR MOLD After a Severe Weather Event

Many South Carolina residents are concerned about indoor mold after severe weather events. DHEC has compiled this informational handout with recommendations to guide decisions regarding mold in homes and workplaces.

Numerical modelling of braided fibres for reinforced concrete

Fire has been always a major concern for designers of steel and concrete structures. Designing fire-resistant structural elements is not an easy task due to several limitations such as the lack of fire-resistant construction materials. Concrete reinforcement cover and external insulation are the most commonly adopted systems to protect concrete and steel from overheating, while spalling of concrete is minimised by using HPFRC instead of standard concrete. Although these methodologies work very well for low rise concrete structures, this is not the case for high-rise and inaccessible buildings where fire loading is much longer. Fire can permanently damage structures that cost a lot of money. This is unsafe and can lead to loss of life. In this research, the author proposes a new type of main reinforcement for concrete structures which can provide better fire-resistance than steel or FRP re-bars. This consists of continuous braided fibre rope, generally made from fire-resistant materials such as carbon or glass fibre. These fibres have excellent tensile strengths, sometimes in excess of ten times greater than steel. In addition to fire-resistance, these ropes can produce lighter and corrosive resistant structures. Avoiding the use of expensive resin binders, fibres are easily bound together using braiding techniques, ensuring that tensile stress is evenly distributed throughout the reinforcement. In order to consider braided ropes as a form of reinforcement it is first necessary to establish the mechanical performance at room temperature and investigate the pull-out resistance for both unribbed and ribbed ropes. Ribbing of ropes was achieved by braiding the rope over a series of glass beads. Adhesion between the rope and concrete was drastically improved due to ribbing, and further improved by pre-stressing ropes and reducing the slacked fibres. Two types of material have been considered for the ropes: carbon and aramid. An implicit finite element approach is proposed to model braided fibres using Total Lagrangian formulation, based on the theory of small strains and large rotations. Modelling tows and strands as elastic transversely isotropic materials was a good assumption when stiff and brittle fibres such as carbon and glass fibres are considered. The rope-to-concrete and strand-to-strand bond interaction/adhesion was numerically simulated using newly proposed hierarchical higher order interface elements. Elastic and linear damage cohesive models were used effectively to simulate non-penetrative 'free' sliding interaction between strands, and the adhesion between ropes and concrete respectively. Numerical simulation showed similar de-bonding features when compared with experimental pull-out results of braided ribbed rope reinforced concrete.

Diagnostico estratégico del suministro de hemocomponentes en Colombia y posibles alternativas de mejora

Objetivo: realizar un diagnóstico respecto a la oferta demanda de hemocomponentes, en el contexto epidemiológico colombiano para que sirva de base en la formulación de futuros modelos logísticos de cadena de suministro que permita responder eficientemente a las necesidades transfusionales del país Método: se realizó un estudio descriptivo retrospectivo basado en las fuentes oficiales de información colombiana respecto a condiciones epidemiológicas poblacionales y su relación respecto a captación y transfusión de sangre, así como las posibilidades de conexiones aéreas. Resultados: actualmente 62.3% de la captación es aportada principalmente por 19% de los bancos de sangre del país (16 / 82), ubicados en 8 ciudades del país las cuales evidencian mejores condiciones de salud e índices de densidad poblacional superiores al promedio nacional. Adicionalmente, desde estas ciudades se puede hacer cubrimiento de hemocomponentes en todo el territorio nacional dadas las condiciones de las conexiones aéreas. Conclusiones: es posible con base en el diagnostico presentado, plantear opciones que apunten a mejorar la eficiencia en la cadena de suministros de hemocomponentes, centralizando la captación de sangre en las áreas donde se cuenta con mejores condiciones de salud y mayores densidades poblacionales. Lo anterior permitiría minimizar los porcentajes de incineración de unidades de glóbulos rojos por vencimiento al mejorar las redes de distribución y de esta manera reducir costos de operación. Debe además fortalecerse la gestión de inventarios desde los servicios de transfusión para lograr minimizar las perdidas. Lo anterior requiere control gubernamental dado que al considerarse la sangre como un bien de interés público, su uso no puede ser indiscriminado.

Aging assessment of polyethylene-based insulated low-voltage cables for nuclear applications

This thesis aims at investigating the evolution of physico-chemical and electrical properties relevant to low-voltage power cables for nuclear application when subjected to typical nuclear power plant (NPP) environments i.e., to gamma radiation and high temperature. This research is part of the European Project Horizon 2020 TeaM Cables, which aims at providing a novel methodology for efficient and reliable NPP cable aging management to NPP operators. The analyzed samples consist of both coaxial and twisted pair cables with different polymeric compounds used as primary insulation. Insulating materials are based on the same silane cross-linked polyethylene matrix with different additives and fillers. In order to characterize the material response to the environmental stresses, various experimental techniques have been used. These characterizations range from the microscale chemical response e.g. by FTIR, OIT and DSC, to the macroscale electrical and mechanical behavior. A significant part of this Thesis is given to the correlation of the response to aging among the different measured properties. It has been shown that it could be possible to connect both the chemical and mechanical properties of the investigated XLPE cables with the electrical ones. In particular, the high-frequency dielectric response allows an effective monitoring of both the early periods of aging, controlled by the antioxidant consumption kinetics, and then the subsequent oxidation of the polymer matrix. Therefore, dielectric spectroscopy showed to be capable of assessing the LV cable aging state and, it might be used as an aging marker for cable diagnostic. The last part of the manuscript focuses on the building of a predictive modelling approach of LV cable conditions subjected to radio-chemical aging. It resulted into obtaining a lifetime curve which relates the aging factor to which the cable is subjected to, namely the dose rate, with the limit value of the considered electrical property (tanδ).

Analysis and detection of partial discharges in an electric motor of a hybrid supercar.

The objective of this thesis was the development of a new detection method of partial discharge (PD) activity in the stator of an electrical hybrid supercar fed by a silicon carbide converter, for which detection with common methods make it very difficult to separate PD pulses from switching noise. This work focused on the analysis and detection of partial discharges making use of an antenna, a peak detector, and an oscilloscope capable of capturing the electromagnetic pulses emitted during PD activity. Validation of the proposed method was done by comparing the partial discharge inception voltage (PDIV) detected by this system with the one obtained from an optical method of proven accuracy, with different rise times and samples. Further development of this method, if proved successful on a full stator, can help increasing the overall reliability of the car, potentially allowing for real time detection of PD activity and predictive maintenance before failure of the insulation system in a hybrid vehicle.

Ri-costruire per ri-generare. Un modello per le periferie urbane

In Italia, quasi il 90% delle abitazioni esistenti sono state edificate prima degli anni Settanta del Novecento, se consideriamo la tipologia costruttiva, le normative per la sicurezza strutturale in ambito sismico e il comportamento energetico, ne deriva che la maggior parte non risponde agli standard vigenti. A questo si aggiunge la consapevolezza che il patrimonio residenziale costruito in quel periodo, e che occupa le prime periferie delle città, non si presta per sua natura costitutiva ad essere oggetto di interventi di riqualificazione che siano giustificabili in termini di costi-benefici dal punto di vista economico e per ottimizzazione ingegneristica. È opportuno ripensare piani e programmi di rinnovamento non circoscritti alle categorie di risanamento, efficientamento, manutenzione, adeguamento, ma che siano in grado di assumere in positivo il tema della sostituzione secondo il paradigma del ri-costruire per ri-generare per sviluppare strategie a medio-lungo termine per soddisfare un quadro esigenziale-prestazionale coerente con la legislazione europea, in termini di sicurezza, efficienza e impatto ambientale, e promuovere la pianificazione e lo sviluppo sostenibile delle città. L’edilizia circolare è qui intesa come un’attività finalizzata alla costruzione e gestione degli edifici all’interno di un ecosistema economico basato sulla circolarità dei processi. L’obiettivo della ricerca è duplice: (i) metodologico, rivolto alla formalizzazione di un modello innovativo d’intervento associato ai principi della circolarità e basato sulla conoscenza approfondita del patrimonio esistente; e (ii) progettuale, prevede la progettazione di un prototipo di unità abitativa e l’applicazione del modello ad un caso di studio, che viene assunto come applicazione sperimentale ad un contesto reale e momento conclusivo del processo. La definizione di una matrice valutativa consente di formulare indicazioni operative nella fase precedente l’intervento per rendere espliciti, attraverso un indice sintetico di supporto decisionale, i criteri su cui fondare le scelte tra le due macro-categorie di intervento (demolizione con ricostruzione o rinnovo).

Edilizia domestica e cultura materiale nelle colonie di Ariminum e Bononia (III-I sec. a.C.)

Il tema affrontato nella presente ricerca sono le trasformazioni intercorse nella vita quotidiana tra il III e il I secolo a.C. in due colonie latine, Ariminum e Bononia, attraverso le evidenze archeologiche. Vengono indagate su scala locale le conseguenze di un fenomeno di grande portata, la colonizzazione romano-latina, mettendo a fuoco le forme dell’abitare, le tradizioni artigianali e le pratiche alimentari. La principale base documentaria sono le testimonianze archeologiche di edilizia domestica e le ceramiche, rinvenute nelle aree di abitato di Rimini e Bologna e nei territori limitrofi. Per cogliere a pieno le trasformazioni intercorse, vengono passate in rassegna le principali caratteristiche del popolamento, dell'architettura domestica e delle ceramiche precedenti la colonizzazione romano-latina. Le due colonie, le abitazioni e le ceramiche sono considerate, inoltre, nel contesto territoriale più ampio, volgendo lo sguardo anche all'area medio-adriatica e alla Cispadana. Allo stesso tempo, sono continui i riferimenti all'Italia medio-tirrenica, poiché permettono di comprendere molte delle evidenze archeologiche e dei processi storici in esame. Il primo capitolo tratta della colonizzazione romano-latina, calata nelle realtà di Rimini e Bologna. La domanda a cui si vuole rispondere è: chi erano gli abitanti delle due colonie? A questo proposito, si affronta anche la questione degli insediamenti precoloniali. Nel secondo capitolo si analizzano le abitazioni urbane. Quali furono le principali innovazioni nell'architettura domestica introdotte dalla colonizzazione? Come cambiarono le forme dell’abitare ad Ariminum e Bononia in età repubblicana? Il terzo capitolo si concentra sulla ceramica per la preparazione e il consumo del cibo nei contesti di abitato. Come cambiarono nelle due città le pratiche alimentari e le tradizioni artigianali utilizzate nella produzione di ceramiche? L'ultimo capitolo discute alcuni quadri teorici applicati ai fenomeni descritti nei capitoli precedenti (romanizzazione, acculturazione, identità, globalizzazione). L'ultimo paragrafo entra nel merito delle trasformazioni avvenute nella vita quotidiana di Ariminum e Bononia.

Discharge characteristics and discharge simulation model of long air gaps containing a floating conductor

Long air gaps containing a floating conductor are common insulation types in power grids. During the transmission line live-line work, the process of lineman entering the transmission line air gap constitutes a live-line work combined air gap, which is a typical long air gap containing a floating conductor. This thesis investigates the discharge characteristics, the discharge mechanism and a discharge simulation model of long air gaps containing a floating conductor in order to address the engineering issues in live-line work. The innovative achievements of the thesis are as follows: (1) The effect of the gap distance, the floating electrode structure, the switching impulse wavefront time, the altitude, and the deviation of the floating conductor from the axis on the breakdown voltage was determined. (2) The physical process of the discharges in long air gaps containing a floating conductor was determined. The reason why the discharge characteristics of long air gaps containing a floating electrode with complex geometrics and sharp protrusions and long air gaps with a rod-shaped floating electrode are similar has been studied. The formation mechanism of the lowest breakdown voltage area of a long air gap containing a floating conductor is explained. (3) A simulation discharge model of long air gaps containing a floating conductor was established, which can describe the physical process and predict the breakdown voltage. The model can realize the accurate prediction of the breakdown voltage of typical long air gaps containing a floating conductor and live-line work combined air gaps in transmission lines. The findings of the study can provide theoretical reference and technical support for improving the safety of live-line work.

Models for reliability estimation of HVDC cable systems

The work carried out in this thesis aims at: - studying – in both simulative and experimental methods – the effect of electrical transients (i.e., Voltage Polarity Reversals VPRs, Temporary OverVoltages TOVs, and Superimposed Switching Impulses SSIs) on the aging phenomena in HVDC extruded cable insulations. Dielectric spectroscopy, conductivity measurements, Fourier Transform Infra-Red FTIR spectroscopy, and space charge measurements show variation in the insulating properties of the aged Cross-Linked Polyethylene XLPE specimens compared to non-aged ones. Scission in XLPE bonds and formation of aging chemical bonds is also noticed in aged insulations due to possible oxidation reactions. The aged materials show more ability to accumulate space charges compared to non-aged ones. An increase in both DC electrical conductivity and imaginary permittivity has been also noticed. - The development of life-based geometric design of HVDC cables in a detailed parametric analysis of all parameters that affect the design. Furthermore, the effect of both electrical and thermal transients on the design is also investigated. - The intrinsic thermal instability in HVDC cables and the effect of insulation characteristics on the thermal stability using a temperature and field iterative loop (using numerical methods – Finite Difference Method FDM). The dielectric loss coefficient is also calculated for DC cables and found to be less than that in AC cables. This emphasizes that the intrinsic thermal instability is critical in HVDC cables. - Fitting electrical conductivity models to the experimental measurements using both models found in the literature and modified models to find the best fit by considering the synergistic effect between field and temperature coefficients of electrical conductivity.