► Indices for long-term evaluation of comfort conditions in building were introduced ► Such indices are described and their scope, strengths and weaknesses are highlighted ► Long-term discomfort ...indices may be used for comfort-optimization of new buildings ► They may be used for operational assessment of thermal comfort in existing buildings ► Improvement objectives are proposed for a new and reliable long-term discomfort index.
A number of metrics for assessing human thermal response to climatic conditions have been proposed in literature over the last decades. They aim at describing human thermal perception of the thermal environment to which an individual or a group of people is exposed. More recently, a new type of “discomfort index” has been proposed in scientific literature, in standards and in guidelines for describing, in a synthetic way, the long-term thermal comfort conditions in buildings and for predicting uncomfortable phenomena. Most of these new indices synthesize the thermal performance of a building in a single value.
We present in this paper a systematic review of 15 indices for the long-term evaluation of thermal comfort conditions in a building. They are here grouped in a limited number of homogenous families according to the assumptions on which they are derived and then they are analyzed according to some key aspects in order to identify their scope, their strengths and weaknesses. Finally, some guidance is provided for future developments.
•We have proposed an in-cylinder pressure-based closed loop combustion control.•We have tested the control on an engine at the test bench.•We have tested the control on the engine equipping a Euro ...6-compliant vehicle.•The control is effective in increasing torque stability and reduce engine noise.
The adoption of diesel LTC combustion concepts is widely recognised as a practical way to reduce simultaneously nitric oxides and particulate emission levels from diesel internal combustion engines. However, several challenges have to be faced up when implementing diesel LTC concepts in real application vehicles. In particular, achieving acceptable performance concerning the drivability comfort, in terms of output torque stability and combustion noise during engine dynamic transients, is generally a critical point. One of the most promising solutions to improve the LTC combustion operation lays in the exploitation of closed loop combustion control, based on in-cylinder pressure signals. In this work, the application of an in-cylinder pressure-based closed loop combustion control to a Euro 6-compliant demonstrator vehicle has been developed. The main challenges deriving from the control of the LTC combustion, directly affecting the engine/vehicle performance, have been analysed in detail. In order to overcome these drawbacks, a new control function, integrated into the base closed loop system, has been designed. The performance of the new function have been experimentally tested at the engine test bench. Results showed a significant enhancement of the LTC operation, in terms of both combustion stability and noise reduction during engine transients. The new function was also implemented on a real vehicle, thus proving the potential of the new control concept in realistic operating conditions.
•We propose an index to assess sustainable development of Italian municipalities.•We composed 99 variables using an ‘objective’ weighting system resulting from PCA.•Labour market, demography and ...income/wealth accounted for the highest weights.•The spatial distribution of the composite index follows a north–south gradient.
In the present study a methodology integrating geographic information systems and multivariate statistics was illustrated with the aim to provide a measure of sustainable development at the local scale. The Factor Weighting Model (FWM) originally proposed by Salvati and Zitti (2008) was used to compose 99 variables (relevant to different research domains such as economic structure, labour market, population dynamics, social characteristics, agriculture and environment) into an index of sustainable development at the municipality scale in a rich but polarized European country (Italy). A Principal Components Analysis has been carried out to explore the relationship among indicators and to estimate their contribution to an a priori defined sustainability target by way of an objective weighting system. Labour market, income and wealth, population dynamics and social structure accounted for the highest weights. The derived index of sustainable development shows a spatially complex distribution in Italy with a marked north–south gradient reflecting the classical socioeconomic disparities observed between competitive and disadvantaged regions. Results can be used as an informative base to implement sustainability policies in countries characterized by persistent socioeconomic disparities.
A single-cylinder diesel engine has been converted into a dual-fuel engine to operate with natural gas together with a pilot injection of diesel fuel used to ignite the CNG–air charge. The CNG was ...injected into the intake manifold via a gas injector on purpose designed for this application. The main performance of the gas injector, such as flow coefficient, instantaneous mass flow rate, delay time between electrical signal and opening of the injector, have been characterized by testing the injector in a constant-volume optical vessel. The CNG jet structure has also been characterized by means of shadowgraphy technique.
The engine, operating in dual-fuel mode, has been tested on a wide range of operating conditions spanning different values of engine load and speed. For all the tested operating conditions, the effect of CNG and diesel fuel injection pressure, together with the amount of fuel injected during the pilot injection, were analyzed on the combustion development and, as a consequence, on the engine performance, in terms of specific emission levels and fuel consumption.
Dual-fuel biodiesel-producer gas combustion has shown potential in reducing nitric oxides and particulate emission levels compared to only diesel operation; however, engine overall efficiency is ...slightly penalized, while the main drawbacks are represented by the higher levels of total hydrocarbons and carbon monoxide emissions.
In this work, the improvements in the combustion development deriving from the splitting of the liquid fuel injection at low loads have been assessed using a 0.51L single-cylinder research diesel engine equipped with a high pressure common rail injection system and operated in dual-fuel mode. In this case, a synthetic producer gas was used as inducted gaseous fuel, while biodiesel was used as pilot fuel.
Initially, the spray morphology was characterized in a constant-volume vessel for different values of injection duration and pressure, as well as vessel backpressure.
Then, the experimental campaign, run on the engine at 1500rpm, was divided in two sessions. During the former, only one pilot injection of constant fuel amount (11mm3/cycle) was performed, the rail pressure was set equal to 500 or 1000bar, the injection timing was varied in the range −50÷5 degrees crank angle after top dead center while the amount of gaseous fuel inducted in the cylinder was varied on three levels. During the latter, the pilot fuel amount, kept equal to the one pilot injection tests, was split in two smaller injections and the effect of the dwell between them – varied in the range 5÷50 degrees crank angle – was investigated as well.
The results of the first set of experiments revealed that pilot injection timing and pressure both affect the combustion development. This resulted in sensible variations on thermal and combustion efficiencies, and therefore on fuel conversion efficiency, the last one exhibiting higher values with pilot injection timing slightly advanced respect to top dead center and lower injection pressure. In these conditions, total hydrocarbons and carbon monoxide are lowered, while nitric oxides are increased. The amount of gas demonstrated to have a secondary effect on combustion development and emissions levels at the exhaust.
Splitting pilot injection, demonstrated to be an effective way to increase fuel conversion efficiency and to reduce the levels of all the pollutant species compared to the single pilot injection strategy. Based on the extensive experimental activity described in this paper, a dwell ranging between 10 and 30 degrees of crank angle, combined with a first injection timing ranging between 35 and 20 degrees of crank angle before top dead center guarantee the highest fuel conversion efficiency and the lowest pollutants emission levels. Injection pressure confirmed to be a significant factor in affecting the combustion development, while a secondary effect was determined by the gaseous mass inducted in the cylinder.
Ultimately, pilot injection splitting demonstrated to be an effective way for improving gaseous fuel combustion in dual-fuel mode at low load (lean mixture) conditions.
Coexisting species may be evolutionarily proximate or distant, resulting in phylogenetically poor or rich communities. This variation is often considered to result from present assembly processes. We ...argue that, under certain conditions, deep-past processes might control the phylogenetic diversity of communities. First, deep-past effects involve macroevolutionary processes, such as diversification rate, niche conservatism, or dispersal, in the lineages that constitute communities. Second, deep-past processes in the respective region or in the habitat type play a role, for instance, through age, area, stability, or connectivity. Third, the deep past may affect communities via trophic interactions (i.e., communities of enemies or mutualists or communities of hosts). We suggest that deep-past effects can be identified in local communities by measuring phylogenetic diversity in different species pools. We also show how community phylogenetic diversity results in positive or negative eco-evolutionary feedback, and we identify present-day conservation challenges that may profit from a deep-time perspective.
The high impact of the building sector on global greenhouse gases (GHG) emissions, has focused the attention on the energetic behaviour of the built environment. Starting from the second half of 20th ...century an increasing attention on the insulation of building envelopes has been paid trying to maximize the indoor-outdoor disconnection. Nowadays, one of the main deficiencies of traditional buildings lies in the rivalry between their static behaviour and the dynamic external environment. The increasing awareness that responsive buildings can provide significant improvements in energy efficiency and internal comfort has recently led to a quick spread of innovative technologies, tools, and research topics. The aim of this review is to provide a broad overview of the available and most promising responsive technologies applied to highly performant buildings with a particular focus on building envelopes. Firstly, an introduction of the energy context and of the spread of adaptive technology is presented. Then, an analysis of the existing nomenclature and classification systems is provided to introduce the detailed review of the technologies.
In Italy, a large outbreak of coronavirus disease 2019 (COVID-19) occurred from 2020 January 30, before the World Health Organization has stated that it is a pandemic. The nationwide quarantine had ...the desired impact of controlling the epidemic, although had presented many challenges, given its large economic and social costs. Complete adherence to recommendations can potentially decelerate and reduce infectious disease outbreaks. To date, it is not clear how compliant the Italian public has been with voluntary home quarantine, neither which factors have influenced an individual's decision to comply with a quarantine order. The purposes of this study were to investigate the degree of the adherence to quarantine restrictions and the factors associated with the self-reported adherence. During the third week of the national lockdown, 3,672 Italian quarantined adult residents (65% females; range, 18-85 years) participated in an online cross-sectional survey focused on the risk perception of contracting COVID-19 and their reported adherence to quarantine protocols. Analysis of variance showed significant differences among demographic groups in tendency to comply with quarantine orders, with women, most educated people, residents of Southern Italy, middle-aged individuals, and health workers more likely to adhere to quarantine guidelines. As well, participants exhibiting the perception, anxiety, and susceptibility of risk of contracting COVID-19 disease were found significantly more likely to adhere to quarantine guidelines. The results of this study can help public health policy makers to recognize target populations for COVID-19 prevention and health education and to understand how inform communication strategies aimed at minimizing the impact and spread of the disease.
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