Search results for "construction"
showing 10 items of 2670 documents
Modeling the natural gas supply chain for sustainable growth policy
2020
Abstract Natural gas has been used globally as a transitional fuel for supporting a green-energy-supply strategy, which has been questioned for the intermittence and lack of reliability of renewables. This paper proposes a System Dynamics model for assessing alternative security of supply policy along the natural gas value chain. The model incorporates demand, transport, production and reserves of natural gas variables according to a systemic perspective. It also includes a module for evaluating the effect of natural gas price on the demand and supply levels, respectively. Alternative supply policies are evaluated under different scenarios. The chosen case-study focuses on the Colombian nat…
Energy and economic analysis of air-to-air heat pumps as an alternative to domestic gas boiler heating systems in the South of Italy
2019
Abstract According to the electricity tariff recently issued by the Italian government for the domestic heating systems fed with heat pumps (HP), an energy and economic analysis was carried out with the aim of investigating the effectiveness of the air-to-air heat pump systems (HPS) as an alternative to the traditional heating using domestic gas boilers systems (GBS). For the purpose of this study, the apartments of three residential buildings were examined. The hourly heating loads were calculated with the ASHRAE radiant time series and the coefficient of performance (COP) of the HPs was evaluated for each operating condition. The costs for the heating system installation and electricity a…
Five-years-long effects of the Italian policies for photovoltaics on the energy demand coverage of grid-connected PV systems installed in urban conte…
2016
Abstract The paper examines the responsiveness of the electricity demand coverage in urban contexts to the changes in the Italian policies for PV systems. The morphological configuration of building roofs according to the number of covered flats, annual data of PV generation and electricity consumptions were considered in the transition from the feed-in tariff (FIT) mechanism to the tax credits scheme currently in force. With the aim of assessing the changes over time in three representative cities, the fluctuations both in the premiums for the produced electricity and the tax credits applied to the PV system costs were observed from July 2010 to February 2016. Furthermore, the main time-va…
Characterization of renewable reductants and charcoal-based pellets for the use in ferroalloy industries
2018
This study investigates the effect of high-temperature pyrolysis and post-treatment processes on spruce and oak charcoal yields and CO2 reactivity in a slow pyrolysis reactor. Post-treatment processes such as co-pyrolysis of biomass and recirculated tar mixture with that to the distillation of the charcoal-tar blend gave similar increase in charcoal yields. From a technological standpoint, co-pyrolysis of charcoal and tar mixture decreased the CO2 reactivity of the charcoal approaching that of fossil-based coke. This emphasize the importance of tar addition and high temperature treatment on charcoal properties. Moreover, the findings of this work show the potential use of the tar organic fr…
Considerations on the optimization of natural gas deliveries by using automated control systems
2019
The current paper aims at optimizing the natural gas deliveries from an underground storage by implementing automated control systems and fiscal measurement systems according to the harmonized European legislation in the area of metrology. In the first part, the authors have carried out an analysis regarding the state of the art at international level with regard to technical solutions for optimizing the deliveries of natural gas by means of a constriction element of a measurement panel. In the following, a software application was created for monitoring the parameters taken from the process gas chromatograph and transferring them to the flow computer by implementing software filters. The n…
Analysis of Possible Concept Solutions of Chain Drives
2019
Possible concept solutions of chain drives are analysed in this paper in order to point out the benefits of chain drive application and, in particular, the possibility of application of multi-level chain drive. The paper also analyses the possibility of replacing the gear drives with chain drives, which, in the case of short-term drive and using the same direction of rotation, enables a slightly simpler drive solution. The paper doesn’t consider difference between the roller and gear chains application because these two types of chains can be used very successfully. Also, the possibility of using timing belt drive is not considered, but it can be also used very successfully in this type of …
Determining efficiency of cycloid reducers using different calculation methods
2019
Cycloid reducers are gear trains which can be classified as planetary transmissions. These transmissions have a very wide range of uses in industry in transporters, robots, satellites, etc. This research presents a comparative analysis of three analytical methods for determining cycloid drive efficiency. The paper explores every mathematically formulated method and compares them to experimental results from literature. The presented methods for determining efficiency have a common property, in that they all determine losses due to friction on the bearing cam surface of the shaft, the rollers of the central gear and the output rollers. The calculation of efficiency values is done for standar…
Considerations on the role of modernizing the road infrastructure in the prevention of road accidents
2019
The realizing and improvement of road infrastructure, of modern road networks provides normal, safe and pleasant road traffic conditions and also help prevent road accidents. The road network, with its constructive characteristics, has to offer optimal conditions for the movement of vehicles, pedestrians and other categories of participants in the road traffic. Starting from the case study of a road sector with heavy road traffic, the current paper analyzes the increase in road safety in Romanian localities along European and national roads through the implementation of specific measures such as setting up sidewalks, installing New Jersey median barriers, expanding the road sectors with 2+1…
Analysis of the Road Risk on the National Road 7 Sector of the Olt River Gorge, between Talmaciu and Calimanesti, for the Years 2011-2018
2019
The study and analysis of the phenomenon of road accidents, that generates risks for the life, physical or psychic integrity and health of humans, but also for material goods, cannot be considered complete without analyzing its dynamics over time and its potential evolution. In this regard, the current paper aims to analyze the general and specific traits of the road risk on the National Road 7, in the Olt River gorge, over a significant time frame, namely 8 years, from 2011 to 2018. This analysis will also be put into context with the most important road factors – the human factor, the road factor, the vehicle factor and not least with the main causes of the road accidents.
Implementation of an occupational stress Control Model
2019
Occupational stress is an enemy of society, a problem that requires a deep research to control stress more effectively. The case study presented in this article consists of a model control regarding occupational stress. The experimental part of this study involved interviews with 15 employees, 9 females and 6 males aged between 25-55 years. Participants described stressful situations at work. Time allocated for each subject was 45 minutes per interviews. The model was implemented based on the job content stressors, effects of stress (physiological, psychological, behavioural) and interviews results. Future directions in stress research is to identify the way to have control in the workplace…