286 research outputs found
Effect of Martian Suspended Dust on Albedo Measurements from the MGS-TES Data
Suspended dust on Mars influences albedo measurements by orbiting instruments, but not necessary the real surface albedo. The aim of this study is to characterize the role of suspended aerosols on albedo measurement by remote sensing instruments
A systematic review of the relationship between family structure and health risk behaviours amongst young people: An African perspective
OBJECTIVE: The aim of this study was to review the published literature on the relationship between family structure and engagement in health risk behaviour amongst youth in African countries.
METHODS: A systematic review was conducted between 2000 and 2014. Suitable titles were identified from database searches. Thereafter, abstracts were evaluated along specific inclusion criteria. Eleven full text articles were evaluated for methodological quality using a modified critical appraisal tool and six studies were included in the final review that satisfied the threshold criterion of 70%. A narrative synthesis was completed for all included records to provide a textual answer to the research question.
RESULTS: Findings indicated that there was a relationship between family structure and engagement in health risk behaviour, specifically risky sexual behaviour. The importance of family structure was evident, and the active involvement of parents in the activities of youth is cardinal. The review further underscores that there is lack of methodologically rigorous research that can provide empirical support for and insight into the relationship between family structure and engagement in health risk behaviour.
DISCUSSION: Risky sexual behaviour was the most prevalent outcome assessed across studies. Family structure impacted positively on delaying or reducing engagement in risky sexual behaviour. Diverse family structures were identified and orphans living with caregivers were identified as a particular structure that might be more prevalent in the African context. Parental involvement and investment in adolescent activities were more strongly identified as an important factor. There is a lack of and need for more methodologically rigorous research to gain empirical support for and insight into the
relationship between family structure and health risk behaviours
A comparative analysis of different future weather data for building energy performance simulation
The building energy performance pattern is predicted to be shifted in the future due to climate change. To analyze this phenomenon, there is an urgent need for reliable and robust future weather datasets. Several ways for estimating future climate projection and creating weather files exist. This paper attempts to comparatively analyze three tools for generating future weather datasets based on statistical downscaling (WeatherShift, Meteonorm, and CCWorldWeatherGen) with one based on dynamical downscaling (a future-typical meteorological year, created using a high-quality reginal climate model). Four weather datasets for the city of Rome are generated and applied to the energy simulation of a mono family house and an apartment block as representative building types of Italian residential building stock. The results show that morphed weather files have a relatively similar operation in predicting the future comfort and energy performance of the buildings. In addition, discrepancy between them and the dynamical downscaled weather file is revealed. The analysis shows that this comes not only from using different approaches for creating future weather datasets but also by the building type. Therefore, for finding climate resilient solutions for buildings, care should be taken in using different methods for developing future weather datasets, and regional and localized analysis becomes vital
Comparing the thermal performance of Living Lab monitoring and simulation with different level of input detail
Dynamic envelope solutions are critical to achieve comfort conditions minimizing the need of active air conditioning systems, emphasizing the potential of thermal adaption of the building occupants.
Dynamic systems are, however, difficult to be implemented in European building energy certification schemes, based on semi-stationary calculation method, standard uses and reference boundary conditions. In the attempt to develop a flexible and dynamic method able to reduce the performance gap between real and expected performance, this paper presents the comparison between measurements and simulations of a Living Lab office operated in thermal free floating, with different strategies for the solar protection and the night ventilative cooling. Simulations were performed using the dynamic platform PREDYCE, which allows for manipulating monitored and simulated data. The first phase was dedicated to the model calibration using the indoor air temperature as relevant indicator against monitored data. The coefficient of variation of the root mean squared error is in the 8-9% range. Building simulations of the calibrated model demonstrated a large variation of the results as a function of the input data, with increase of discomfort hour up to a factor 20 and a reduction of discomfort hours up to 95%
Road Thermal Collector for Building Heating in South Europe: Numerical Modeling and Design of an Experimental Set-Up
The combination/integration of renewable energy and storage systems appears to have significant potential, achieving high-energy results with lower costs and emissions. One way to cover the thermal needs of a building is through solar energy and its seasonal storage in the ground. The SMARTEP project aims to create an experimental area that provides for the construction of a road solar thermal collector directly connected to a seasonal low-temperature geothermal storage with vertical boreholes. The storage can be connected to a ground-to-water heat pump for building acclimatization. This system will meet the requirements of visual impact and reduction of the occupied area. Nevertheless, several constraints related to the radiative properties of the surfaces and the lack of proper thermal insulation have to be addressed. The project includes the study of several configurations and suitable materials, the set-up of a dynamic simulation model and the construction of a small-scale road thermal collector. These phases allowed for an experimental area to be built. Thanks to careful investigation in the field, it will be possible to identify the characteristics and the best operation strategy to maximize the energy management of the whole system in the Mediterranean area
PERIPHERAL TOURISM ENTREPRENEURS IN A RESOURCE-CONSTRAINED ENVIRONMENT: EVIDENCE FROM EASTERN CAPE PROVINCE, SOUTH AFRICA
The tourism industry is distinguished from many other economic activities by the dominance of small-scale enterprises
and micro-firms. Small tourism firms are critical change agents for destinations, local economic development and poverty reduction
most especially in peripheral regions. This paper is situated within a growing international literature on tourism entrepreneurship and
specifically the characteristics and motivations of small tourism entrepreneurs and their business operations. The research is
conducted in Eastern Cape province of South Africa which is a resource-scarce or resource-constrained environment. Results are
presented from a survey of 79 Black-owned small accommodation businesses and 19 semi-structured interviews with key
stakeholders. It is shown that women own and operate the majority of these small accommodation businesses. These are mainly bed
and breakfast establishments or small guest houses for which the clientele is mostly business tourists and government employees in
particular. Issues under scrutiny are business motivations, start-up and operational issues. Networking emerges as an important
business strategy for these peripheral entrepreneurs to address the challenges of business development. Overall, this study
provides original findings and fresh insight into a segment of peripheral entrepreneurs operating in a resource-scarce context
Set-up and Calibration by Experimental Data of a Numerical Model for the Estimation of Solar Factor and Ug-value of Building Integrated Photovoltaic Systems☆
Abstract The acronym BIPV (Building Integrated Photovoltaics) refers to the installation of photovoltaic systems which, in addition to convert solar energy into electrical energy, have a high level of architectonical integration with the built environment, becoming a real architectural cladding to be installed over the buildings in place of traditional envelope systems. Many typologies of BIPV have been developed, however their thermal characteristics such as g and Ug-value are not well evaluated and require more detailed analyses considering that they could replace large extension of traditional building envelope. A first approach to address this problem is proposed in this work. A mathematical model based on a finite differences scheme for the estimation of the thermal parameters g and Ug-value has been developed and tuned using experimental value measured on sample BIPV with a Hot Plate and a Solar Calorimeter. The results of the model show that the introduction of solar cells in a laminated glass or in a double glass leads to a reduction of energy parameters modifying winter and summer energy balance of the building system
Effects of soiling and weathering on the albedo of building envelope materials: Lessons learned from natural exposure in two European cities and tuning of a laboratory simulation practice
Chemical and physical stress, weathering, organic and inorganic matter deposition, and microbial growth over time, or \u201caging\u201d, affect the optical-radiative performance of building envelope materials. Natural exposure helps to quantify these effects, but it usually requires several years. Further, the contribution of the different degradation agents cannot be isolated, and results from different campaigns cannot be easily compared because of the variability in the boundary conditions producing aging. Here we present an adaptation of the protocol implemented by ASTM as D7897-18 \u201cStandard Practice for Laboratory Soiling and Weathering of Roofing Materials to Simulate Effects of Natural Exposure on Solar Reflectance and Thermal Emittance\u201d. The aim is to reproduce in the laboratory the changes in albedo (solar reflectance) and thermal emittance experienced by building envelope materials in European urban areas rather than in the United States. We tuned the spraying duration and weathering cycles, and we compared the UV\u2013vis\u2013NIR reflectances of naturally-aged specimens (48 months in Rome and Milan) of roofing and wall finish materials to those exposed to laboratory weathering and soiling. Excluding those materials that show early physical-chemical degradation, the mean absolute deviation between natural and laboratory exposure of roofing products is equal to 0.027 in albedo. This is a lower value than the differences between two natural exposure campaigns at the same site. We clearly defined the limits of application of the protocol, providing an appraisal of the repeatability of natural aging. Moreover, we identified possible improvements in the methodology to conduct both natural and laboratory exposure
Involucro trasparente a carattere dinamico e adattativo tramite l’integrazione di Phase Change Materials in elementi schermanti, ai fini della riduzione della domanda energetica per raffrescamento e illuminazione artificiale
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