Quantity surveyor | EPFL Graph Search

A quantity surveyor (QS) is a construction industry professional with expert knowledge on construction costs and contracts. Qualified professional quantity surveyors are known as Chartered Surveyors (Members and Fellows of RICS) in the UK and Certified Quantity Surveyors (a designation of AIQS) in Australia and other countries. In some countries such as Canada, South Africa, Kenya and Mauritius, qualified quantity surveyors are known as Professional Quantity Surveyors, a title protected by law. Quantity surveyors are responsible for managing all aspects of the contractual and financial side of construction projects. They help to ensure that the construction project is completed within its projected budget. Quantity surveyors are also hired by contractors to help with the valuation of construction work for the contractor, help with bidding and project budgeting, and the submission of bills to the client. Duties The duties of a quantity surveyor are as follows:

Cost estima

Neural Network Potentials for Age Hardening Aluminum Alloys

Daniel John Gilles Marchand

High-strength metal alloys achieve their performance via careful control of precipitates and solutes.The nucleation, growth, and kinetics of precipitation, and the resulting mechanical properties, are inherently atomic scale phenomena, particularly during early-stage nucleation and growth. Atomistic modeling using interatomic potentials is a desirable tool for understanding the detailed phenomena involved in precipitation and strengthening, which requires length and time scales far larger than those accessible by first-principles methods. Current interatomic potentials for alloys are not, however, sufficiently accurate for such studies.In this work we will consider new interatomic potentials for the 2xxx (Al-Cu-Mg), 6xxx (Al-Mg-Si), and 7xxx (Al-Zn-Mg-Cu) age-hardenable aluminum alloys. First a family of neural-network potentials (NNPs) for the Al-Cu system are presented as a simple example of a machine-learning potential that can achieve near-first-principles accuracy for many different metallurgically-important aspects of 2xxx alloys. High fidelity predictions of intermetallic compounds, elastic constants, dilute solid-solution energetics, precipitate/matrix interfaces, generalized stacking fault energies and surfaces for slip in matrix and precipitates, antisite defect energies, and other quantities, are shown. The NNPs also captures the subtle entropically-induced transition between

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and

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at temperatures around 600K. Many comparisons are made with the state-of-the-art Angular-Dependent Potential for Al-Cu, demonstrating the significant quantitative benefit of a machine-learning approach. A preliminary kinetic Monte Carlo study shows the NNP to predict the emergence of GP zones in Al-4at%Cu at T=300K in agreement with experiments.Then, a family of NNPs for the Al-Mg-Si system is developed to enable quantitative studies of 6xxx alloys. The NNP is trained on metallurgically-important quantities computed by first principles density function theory (DFT) leading to high fidelity predictions of intermetallic compounds, elastic constants, dilute solid-solution energetics, precipitate/matrix interfaces, Al stacking fault energies, antisite defect energies, and other quantities. The Generalized Stacking Fault Energy surfaces (GSFE) for the three prevalent

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precipitate compositions in peak-aged Al-6xxx are then computed with the NNP, and are validated by DFT computations at key points. A preliminary examination of early-stage clustering kinetics and energetics in Al-6xxx is then made, showing the formation of low-energy Mg-Si structures and the trapping of vacancies in these clusters.Finally we demonstrate a family of NNPs to produce what we believe to be the first Al-Cu-Mg (2xxx) and Al-Cu-Mg-Zn (7xxx) potentials of sufficient accuracy to be used for atomistic simulations. These NNP studies show that the NNP has significant transferability to defects and properties outside the structures used to train the NNP, but also shows some errors highlighting that the use of any interatomic potential requires careful validation in application to specific metallurgical problems of interest.

EPFL2022

Daylight and temperature in buildings: interaction effects on human responses

Giorgia Chinazzo

Over the past years, increasing efforts have been devoted to understand how people perceive the indoor environment with the goal to improve building design and operation. Studies have separately addressed the effects of the four main aspects that influence the perception of the indoor environment, i.e., visual appearance, thermal condition, acoustic ambiance, and air quality. However, building occupants are simultaneously exposed to multiple indoor stimuli and their perception of the indoor environment depends on the mutual combination and interaction of such stimuli. Despite the increasing interest in the topic, few studies on the interactions between indoor factors are available. Most of them have focused on interactions between thermal and visual factors due to their large implications for energy consumption and building design. In this context, electric lighting has been primarily used as visual stimulus, leaving a knowledge gap on interaction effects in daylit environments. To address this challenge, this doctoral thesis focuses on the effects of visual and thermal interactions on human responses, with the use of daylight as the sole source of light. Two types of visual-thermal combinations are investigated: temperature and "daylight color" (i.e., daylight transmitted through colored glazing) and temperature and daylight quantity (i.e., illuminance levels). The aim of this work is threefold: (i) understand the effect of daylight color and quantity on thermal perceptual and physiological responses; (ii) investigate the influence of indoor temperature on visual perception of daylight; and (iii) explore the effect of daylight and temperature combination on the overall comfort perception. To address the previous aspects, four experiments were conducted. Two of them were carried out in an office-like test room to investigate both visual-thermal combinations. One field study was performed to further explore temperature and daylight quantity interactions. One experiment was conducted in a test room with the use of virtual reality to further investigate temperature and "daylight color" interactions. The results of this thesis show that daylight and temperature do interact, influencing human responses in a perceptual rather than in a physiological way. The interaction effects are bi-directional, as temperature influences visual perception, and daylight color and quantity affects thermal perception. Daylight conditions and indoor temperatures simultaneously and equally contribute to the overall comfort perception, but only after a relatively long exposure to the visual stimulus. The findings of this research suggest that indoor factors should not be considered separately but in combination. The integration in both research and practice of interaction effects between indoor factors will ultimately contribute to the improvement of comfort conditions inside buildings. Potentially, this integration will also allow to reduce the energy consumed in buildings to guarantee occupants' comfort due to the extension of the comfort ranges that currently neglect interaction effects between indoor environmental factors. Disentangling for the first time the complex relationship between daylight and indoor temperature, this research constitutes an additional step towards understanding interactions of indoor factors and contributes to the establishment of a comfortable and energy-efficient built environment.

EPFL2019

Low Carbon Pathways for Structural Design

Catherine Elvire L. De Wolf

To avoid an increase in greenhouse gas emissions, a depletion of resources, and waste accumulation, structural engineers have a major role to play in low carbon structural design. For example, cement- based materials represent one-third of all materials extracted each year [1]. This paper offers three pathways for lowering the embodied carbon of building structures – the emissions related to material extraction, production, transport, construction, maintenance and demolition – through the lens of three case studies of building structures in Switzerland. The first pathway focuses on the structural scale by reducing material intensities in terms of material use per unit of floor area. The second pathway focuses on the material scale by lowering the impact of the materials themselves through the choices of the materials typically used in structures. The third pathway focuses on potential changes to current construction practices by (re-)introducing reuse strategies in the building sector. A simplified version of Life Cycle Assessment (LCA) is used to evaluate each Swiss case study compared to current practice. The material quantities are collected from literature, architectural drawings, Bill of Quantities (BoQ), and Building Information Models (BIM). This research illustrates the challenges and opportunities of three pathways for low carbon structural design: the optimization of material efficiency, the use of low- carbon materials, and the reuse of structural elements from other demolition sites.

2018