Abstract
This paper aims at presenting the development of a calibrated building energy simulation model of a school building to study the impact of improving the ventilation system on energy performance. The simulation model was developed with the DesignBudderlEnergyplus software and it was calibrated based on data collected during an energy audit to the school building. Schools need high outdoor airflow rates to remove indoor air contaminants related to occupants and building components, thus requiring mechanical ventilation systems. Due to budget restrictions, school managers decided to schedule the building management system to keep the HVAC systems active only between 6:00 am and 10:00 am. According to the values measured in this school, it was patent that the CO2 concentration was too high in certain periods. Too high peak values undermine the indoor air quality in the remaining occupancy time of the classroom, harming the work conditions for teachers and students. To solve this problem, an extended usage schedule of the mechanical ventilation was simulated (8:00 am to 5:00 pm) according to the required enhancement of indoor air quality, which together with the adoption of the new calculated fresh air flow rates will enhance air quality while avoiding excessive cost, thus increasing energy efficiency. (C) 2017 The Authors. Published by Elsevier Ltd.

Abstract
Located in the northern part of continental Portugal, the city of Porto is characterized by low-to-moderate levels of seismicity, thus one of reasons for the lack of studies regarding the influence of site effects in this area. In this study, the HVSR technique (horizontal-to-vertical spectral ratio) was used in order to obtain information about the fundamental frequencies of the ground in several parts of the city which was later compared to the geotechnical information presented in the Geotechnical Map of Porto, with the aim of establishing a possible correlation between frequency values and sub-soil geotechnical characteristics. This type of research plays an important role in understanding how local geological characteristics may influence the amplification of seismic waves. For this purpose, two types of studies were conducted in the city of Porto – two linear test campaigns along two major streets in the city, Boavista Avenue and Constituição Street; and one dispersed test campaign within the hydrographic basin of Frio River, an underground river flowing in the areas of Carregal Garden, Santo António Hospital, Cordoaria Garden and Virtudes Garden. The three campaigns represented a total of 53 recordings of ambient ground noise using a broad band seismometer and the resulted data was used to produce HVSR graphics. From these graphics it was possible to determine the fundamental frequencies (f0) of several points within the city. Resorting to the geotechnical map of the city and having identified the geotechnical units existing in each test place as well as the parameters used to their classification, it was possible to establish a connection between frequency values and substrate competence. The results suggest a strong relation between these parameters, low frequencies relate to softer grounds and as an opposite high frequencies to harder bedrock.

Abstract

Abstract
Urban form is an important driver of energy demand and therefore of GHG emissions in urban areas. Yet, research on urban form and energy remains sectorial and hasn't been able to deliver a full understanding of the impact of the physical structure of cities upon their energy demand. Most common approaches feature engineering models in buildings, and statistical models in transports. This study aims at contributing to the characterization of the link between urban form and energy considering altogether three distinct energy uses: ambient heating and cooling in buildings, and travel. A high-resolution methodology is proposed. It applies GIS to provide the analysis with a spatially-explicit character, and neural networks to model energy demand based on a set of relevant urban form indicators. The results confirm that the effect of urban form indicators on the overall energy needs is far from being negligible. In particular, the number of floors, the diversity of activities within a walking reach, the floor area and the subdivision of blocks evidenced a significant impact on the overall energy demand of the case study analyzed.

Abstract

Abstract
In this article we propose a decagonal photonic crystal fiber (D-PCF) consisting unique cladding without structural complexity having very high birefringent of the order of 10-2, less effective area of few square microns as well as low confinement loss of the order of 10-2 dB/m at 1.55 µm wavelength. The zero dispersion wavelength is also achieved in the near infrared region. This study clearly attributes to the fact that the zero dispersion wavelength at the near infrared region, very high birefringence and low confinement loss can be adjusted according to the necessity by changing the structural parameters with considerable fabrication tolerance. This fiber can prove itself useful in laser technology, telecommunication, non-linear application, sensor technology and also in making polarization maintaining devices. © 2017 Elsevier B.V.