Labour and Low Energy Buildings: the energy performance gap as Social Practice

Buildings are responsible for approximately 30% of EU end-use emissions (Bettgenhäuser , et al, 2009) and are at the forefront of efforts to meet emissions targets arising from their design, construction and operation. For the first time in its history, construction industry outputs must meet specific energy targets if planned reductions in greenhouse gas emissions are to be achieved through nearly zero energy buildings (nZEB) (EC, 2010) supported by on-site renewable heat and power. Where individual UK dwellings have been tested before occupation to assess whether they meet energy design criteria, the results indicate what is described as an ‘energy performance gap’, that is, energy use is almost always more than that specified. This leads to the conclusion that the performance gap is, inter alia, a function of the labour process and thus a function of social practice. Social practice theory, based on Schatzki’s model (2002), is utilised to explore the performance gap as a result of the changes demanded in the social practice of building initiated by new energy efficiency rules. The paper aims to open a discussion where failure in technical performance is addressed as a social phenomenon.

A laboratory study of water ice erosion by low-energy ions

Water ice covers the surface of various objects in the outer Solar system.Within the heliopause, surface ice is constantly bombarded and sputtered by energetic particles from the solar wind and magnetospheres. We report a laboratory investigation of the sputtering yield of water ice when irradiated at 10 K by 4 keV singly (13C+, N+, O+, Ar+) and doubly charged ions (13C2+, N2+, O2+). The experimental values for the sputtering yields are in good agreement with the prediction of a theoretical model. There is no significant difference in the yield for singly and doubly charged ions. Using these yields, we estimate the rate of water ice erosion in the outer Solar system objects due to solar wind sputtering. Temperature-programmed desorption of the ice after irradiation with 13C+ and 13C2+ demonstrated the formation of 13CO and 13CO2, with 13CO being the dominant formed species.

What kind of expertise is needed for low energy construction

The construction industry is responsible for 40% of European Union (EU) end-use emissions but addressing this is problematic, as evident from the performance gap between design intention and on-site energy performance. There is a lack of the expertise needed for low energy construction (LEC) in the UK as the complex work processes involved require ‘energy literacy’ of all construction occupations, high qualification levels, broad occupational profiles, integrated teamworking, and good communication . This research identifies the obstacles to meeting these requirements, the nature of the expertise needed to break down occupational divisions and bridge those interfaces where the main heat losses occur, and the transition pathway implied. Obstacles include a decline in the level, breadth and quality of construction vocational education and training (VET), the lack of a learning infrastructure on sites, and a fragmented employment structure. To overcome these and develop enhanced understanding of LEC requires a transformation of the existing structure of VET provision and construction employment and a new curriculum based on a broader concept of agency and backed by rigorous enforcement of standards. This can be achieved through a radical transition pathway rather than market-based solutions to a low carbon future for the construction sector.

DNA damage induced by low energy electrons (LEEs)

Abstract : The major objective of our study is to investigate DNA damage induced by soft X-rays (1.5 keV) and low-energy electrons (˂ 30 eV) using a novel irradiation system created by Prof. Sanche’s group. Thin films of double-stranded DNA are deposited on either glass and tantalum substrates and irradiated under standard temperature and pressure surrounded by a N[subscript 2] environment. Base release (cytosine, thymine, adenine and guanine) and base modifications (8-oxo-7,8-dihydro -2’-deoxyguanosine, 5-hydroxymethyl-2’-deoxyuridine, 5-formyl-2’-deoxyuridine, 5,6-dihydrothymidine and 5,6-dihydro-2’-deoxy uridine) are analyzed and quantified by LC-MS/MS. Our results reveal larger damage yields in the sample deposited on tantalum than those on glass. This can be explained by an enhancement of damage due to low-energy electrons, which are emitted from the metal substrate. From a comparison of the yield of products, base release is the major type of damage especially for purine bases, which are 3-fold greater than base modifications. A proposed pathway leading to base release involves the formation of a transient negative ion (TNI) followed by dissociative electron attachment (DEA) at the N-g lycosidic bond. On the other hand, base modification products consist of two major types of chemical modifications, which include thymine methyl oxidation products that likely arises from DEA from the methyl group of thymine, and 5,6-dihydropyrimidine that can involve the initial addition of electrons, H atoms, or hydride ions to the 5,6-pyrimidine double bond.

The effect of neutron irradiation on the density of low-energy excitations in vitreous silica

Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C , the thermal conductivity K, ex and the anomalous temperature dependence of the ultrasound velocity Deltav/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that K and Deltav/v are determined by the same localized excitations responsible for C , but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. Furthermore, a consistent account for the measured C , K, ex and Deltav/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.

Analysis and improvement of the envelope, heating and ventilation of a low energy building with district heating

In this thesis project, a building in Vegagatan 12, Gävle has been analysed in order to see why it does consume more energy than it was expected. This building is a low energy building certified by Miljöbyggnad and it should use less than 55kWh/m2 year and nowadays it is using 62.23 kWh/m2. To get the needed data, some information about the building has been gathered, some measurements have been done in the building and some calculations have been done with those measurements. Finally, some possible solutions have been offered to reduce the energy use of the building. Insulating the floor, the pipes and the walls, reducing the indoor temperature in winter... All of these changes need the help of environmentally friendly attitudes, which is a very important fact in low energy buildings.

Design of a wearable platform for PPG analysis with multicore low-power processor

Photoplethysmography (PPG) sensors allow for noninvasive and comfortable heart-rate (HR) monitoring, suitable for compact wearable devices. However, PPG signals collected from such devices often suffer from corruption caused by motion artifacts. This is typically addressed by combining the PPG signal with acceleration measurements from an inertial sensor. Recently, different energy-efficient deep learning approaches for heart rate estimation have been proposed. To test these new solutions, in this work, we developed a highly wearable platform (42mm x 48 mm x 1.2mm) for PPG signal acquisition and processing, based on GAP9, a parallel ultra low power system-on-chip featuring nine cores RISC-V compute cluster with neural network accelerator and 1 core RISC-V controller. The hardware platform also integrates a commercial complete Optical Biosensing Module and an ARM-Cortex M4 microcontroller unit (MCU) with Bluetooth low-energy connectivity. To demonstrate the capabilities of the system, a deep learning-based approach for PPG-based HR estimation has been deployed. Thanks to the reduced power consumption of the digital computational platform, the total power budget is just 2.67 mW providing up to 5 days of operation (105 mAh battery).

Sensors on mobile devices for AAL

Com o envelhecimento da população, as preocupações com a garantia do seu bem-estar aumentam criando a necessidade de desenvolver ferramentas que permitam monitorizar em permanência este sector da população. A utilização de smartphones pelos mais velhos pode ser crucial no seu bem-estar e na sua autonomia contribuindo para a recolha de informação importante já que estes estão muitas vezes equipados com sensores que podem dar indicações preciosas ao cuidador sobre o estado atual do paciente. Os sensores podem fornecer dados sobre a atividade física do paciente, bem como detetar quedas ou calcular a sua posição, com a ajuda do acelerómetro, do giroscópio e do sensor de campo magnético. No entanto, funcionalidades como essas requerem, obrigatoriamente, uma frequência de amostragem mínima por parte dos sensores que permita a implementação de algoritmos, que determinarão esses parâmetros da forma mais exata possível. Dado que nem sempre os pacientes se fazem acompanhar do seu smartphone quando estão na sua residência, a criação de ambientes de AAL (Ambient Assisted Living) com recurso a dispositivos externos que podem ser “vestidos” pelos pacientes pode também ser uma solução adequada. Estes contêm normalmente os mesmos sensores que os smartphones e comunicam com estes através de tecnologias sem fios, como é o caso do Bluetooth Low Energy. Neste trabalho, avaliou-se a possibilidade de alteração da frequência dos sensores em diferentes sistemas operativos, tendo sido efectuadas modificações nas instalações por defeito de alguns sistemas operativos abertos. Com o objectivo de permitir a criação de uma solução de AAL com recurso a um dispositivo externo implementaram-se serviços e perfis num dispositivo externo, o SensorTag.

An Encoded Infrared Sheet Of Light Navigational Beacon System For Precise Localization Of Indoor Mobile Robot Vehicles

A new localization approach to increase the navigational capabilities and object manipulation of autonomous mobile robots, based on an encoded infrared sheet of light beacon system, which provides position errors smaller than 0.02m is presented in this paper. To achieve this minimal position error, a resolution enhancement technique has been developed by utilising an inbuilt odometric/optical flow sensor information. This system respects strong low cost constraints by using an innovative assembly for the digitally encoded infrared transmitter. For better guidance of mobile robot vehicles, an online traffic signalling capability is also incorporated. Other added features are its less computational complexity and online localization capability all these without any estimation uncertainty. The constructional details, experimental results and computational methodologies of the system are also described

Ibeacon una nuova tecnologia per la localizzazione in ambienti chiusi.

Tesi di rassegna sugli iBeacon, tecnologia di brand Apple basata su Bluetooth Low Energy

Spatial computing per dispositivi mobile ed embedded

Questa tesi si focalizza sulle possibili tecnologie per realizzare comunicazioni opportunistiche fra dispositivi mobile ed embedded, con l'obiettivo di integrarle nel contesto di sistemi a larga scala situati, e con particolare riferimento al prototipo denominato "Magic Carpet". Vengono considerate in particolare le tecnologie WiFi ad-hoc e Bluetooth Low Energy su Android e Raspberry Pi.

Indoor position, localizzazione e tracciamento in ambienti chiusi

Le grandi catene di distribuzione, per sviluppare strategie commerciali sempre più efficaci, sono interessate a comprendere il percorso che ogni cliente effettua all’interno del punto vendita, che reparti visita, il tempo di permanenza in un’area specifica ecc… Quindi è stato necessario trovare un sistema per localizzare e tracciare un cliente all’interno di un ambiente chiuso (indoor position). Prima di tutto ci si è concentrati sulla ricerca e sviluppo di una nuova idea che potesse superare gli ostacoli delle soluzioni attualmente in commercio. Si è pensato di sostituire le tessere punti del punto vendita con delle tessere bluetoothLE e di creare un sistema di posizionamento al chiuso utilizzando la stessa logica di funzionamento del GPS per gli ambienti aperti. Il ricevitore è la tessera BLE posseduta dal cliente e i satelliti sono tre device Android dotati di un’app specifica per rilevare il segnale radio (RSSI) emesso dalla tessera ogni secondo. Le rilevazioni dei tre device Android sono successivamente trasferite all’interno di una web application che si occupa di elaborare i dati tramite il processo di trilaterazione. L’output sono le coordinate x,y di ciascuna tessera in ogni secondo di visita all’interno del punto vendita. Questi dati sono infine utilizzati per mostrare graficamente il percorso effettuato dal cliente, l’orario di ingresso e di uscita e il tempo di permanenza. Riepilogando, il progetto comprende una fase di ricerca e intuizione di una nuova idea, una fase di progettazione per traslare i meccanismi del funzionamento GPS all’utilizzo in un ambiente chiuso, una fase di implementazione dell’app e della web application e infine una fase di sperimentazioni sul campo che si concluderà dopo la laurea con test reali in un supermercato della zona.