101 research outputs found
NETS FOR PEACH PROTECTED CULTIVATION
The aim of this paper was to investigate the radiometric properties of coloured nets used to protect a peach cultivation. The modifications of the solar spectral distribution, mainly in the R and FR wavelength band, influence plant photomorphogenesis by means of the phytochrome and cryptochrome. The phytochrome response is characterized in terms of radiation rate in the red wavelengths (R, 600-700 nm) to that in the farred radiation (FR, 700-800 nm), i.e. the R/FR ratio. The effects of the blue radiation (B, 400-500 nm) is investigated by the ratio between the blue radiation and the far-red radiation, i.e. the B/FR ratio. A BLUE net, a RED net, a YELLOW net, a PEARL net, a GREY net and a NEUTRAL net were tested in Bari (Italy), latitude 41° 05' N. Peach trees were located in pots inside the greenhouses and in open field. The growth of the trees cultivated in open field was lower in comparison to the growth of the trees grown under the nets. The RED, PEARL, YELLOW and GREY nets increased the growth of the trees more than the other nets. The nets positively influenced the fruit characteristics, such as fruit weight and flesh firmness
Engineering problems and aspects of the technological equipment in Space Plant Growth Systems
As human presence in space becomes longer, supplying all food, oxygen and water
from Earth will result in a tremendous cost. For this reason the international scientific
community has been making efforts towards developing technologies and equipment to
realise a sustainable Bioregenerative Life Support System for food production, water
purification, air revitalisation and waste recovery. Plants produce food and oxygen for
human needs, contribute to remove and reclaim carbon dioxide, relative humidity and
the organic wastes. Aim of this research is a critical analysis of the materials and
equipment requirements used up to now, in order to highlight the equipment
engineering solutions for a system for plant cultivation on-board the International Space
Station supported by Italian Space Agency. Creating a Bioregenerative Life Support
System is an extremely sophisticated scientific problem. Space environment is
characterised by the absence of the Earth’s gravitational and magnetic fields, of tidal
forces and of the influence of the cyclical events of celestial mechanics and so, the
prediction of fluid and heat behaviour is less intuitive. Besides, this environment would
severely impact plant growth and metabolism. In space an enclosed environmentallycontrolled
plant growth system must control and regulate the atmospheric parameters
and the atmospheric gas composition, provide light energy for photosynthesis and
supply the plants with the appropriate nutrient and water to support photosynthesis and
to compensate for the evaporation and transpiration losses
Evaluation of the radiometric properties of roofing materials for livestock buildings and their effect on the surface temperature
Passive systems, such as high solar reflective roofing materials, protective facades, vegetative green walls and roofs, can be used in order to control solar heat gain in buildings. These sustainable technologies can reduce the temperature of the external surface of the building envelope, so reducing the energy consumption for cooling in summer. The radiometric properties of metallic roofing materials and their effects on the surface temperature were evaluated. Nine smooth metallic materials used for livestock buildings were tested; 4 were made of aluminium and the other 5 of steel and they were characterised by different colours. Solar reflectivity and long wave infrared emissivity were evaluated by means of laboratory tests; the influence of the radiometric properties on the surface temperature was evaluated in the field by using an experimental structure in Summer. The solar reflectivity coefficient ranged from 7.1% for the brown aluminium to 40.1% for the red steel; significant differences of the temperatures were recorded when the solar radiation hitting the metallic surface was higher than 600 W m-2. A difference of 13.4% of the solar reflectivity coefficient resulted in a difference of the surface temperature of up to 8 °C. Variation of the slope from 15° to 40° resulted in an increase of the surface temperature of more than 8 °C. The value of the convection coefficient was calculated by means of the data measured in the field, and the mean value was equal to 12.2 W m-2 K-1
Correlation between agrochemicals, solar radiation and mechanical properties of greenhouse plastic films
A research was carried out in order to evaluate how agrochemicals contamination and solar radiation influence the mechanical properties of ethylene-vinyl acetate copolymer (EVA) films. The films, manufactured adding several different combinations of light stabilizers, were subjected to natural and artificial weathering and to three agrochemicals commonly used during the cultivation practices. Two sets of field trials were carried out from 2006 to 2007 at the experimental centre of the University of Bari (Italy). The films, installed on steel arches of low tunnels, were periodically sprayed with the agrochemicals containing iron, chlorine and sulphur. For control the same films, mounted over other low tunnels, were not sprayed. Stress and strain at break of the film samples, taken at fixed time intervals in the field and after exposure in an artificial ageing chamber, were measured. Tests were conducted to evaluate the chemical contaminants absorbed by the films. Solar radiation falling on the films under test was continuously measured and recorded by means of a pyranometer and a CR10x Campbell data logger. The results of the tests showed that the different light stabilizers influenced the behaviour of the films in presence of the sprayed agrochemicals. The experimental data were investigated evaluating the cumulative solar radiation, the kind of anti-UV additive and the absorbed contaminants. Concerning the agrochemicals which were absorbed by the films, values up to 6800 ppm of sulphur were recorded during the tests. The research allowed the identification of the suitable additives in relation with used agrochemicals. The tests showed that an improved resistance to the agrochemicals was recorded for the EVA film stabilized with NOR-HALS plus UV filter
Effects of agrochemicals, ultra violet stabilisers and solar radiation on the radiometric properties of greenhouse films
Agrochemicals, based on iron, sulphur and chlorine, generate by products that lead to a degradation of greenhouse films together with a decrease in their mechanical and physical properties. The degradation due to agrochemicals depends on their active principles, method and frequency of application, and greenhouse ventilation. The aim of the research was to evaluate how agrochemical contamination and solar radiation influence the radiometric properties of ethylene-vinyl acetate copolymer greenhouse films by means of laboratory and field tests. The films, manufactured on purpose with the addition of different light stabiliser systems, were exposed to natural outdoor weathering at the experimental farm of the University of Bari (Italy; 41° 05' N) in the period from 2006 to 2008. Each film was tested for two low tunnels: one low tunnel was sprayed from inside with the agrochemicals containing iron, chlorine and sulphur while the other one was not sprayed and served as control. Radiometric laboratory tests were carried out on the new films and on samples taken at the end of the trials. The experimental tests showed that both the natural weathering together with the agrochemicals did not modify significantly the radiometric properties of the films in the solar and in the photosynthetically active radiation wavelength range. Within six months of experimental field tests the variations in these radiometric characteristics were at most 10%. Significant variations, up to 70% of the initial value, were recorded for the stabilised films in the long-wave infrared radiation wavelength range
WINTERTIME THERMAL PERFORMANCE OF GREEN FAÇADES IN A MEDITERRANEAN CLIMATE
The increasing environmental issues have afforded opportunities for a widespread application of green
systems in urban areas. Greening the building with green roofs and vertical green systems can be a
design and retrofitting strategy to improve building energy performance in summer and in winter.
Research efforts have been mainly concentrated on their energy saving function during warm periods.
Green façades have a great application potential thanks to the space available in urban environment.
The effect of green façades on building energy performance has been studied mainly for warm periods.
In order to evaluate the effect during cold periods, an experiment was conducted in Bari, Italy, for two
years. Pandorea jasminoides variegated and Rhyncospermum jasminoides were tested as evergreen
climbing plants on walls; a third wall was used as control. The night-time temperature of the covered
wall was higher than the uncovered wall temperature by up to 3.5°C, thanks to the presence of plants.
The thermal barrier function performed by the vegetation layer was analysed. The influence of outdoor
air temperature, relative humidity and wind velocity on the façades thermal effect during night-time
was investigated. The experimental test demonstrated that both Pandorea jasminoides variegated and
Rhyncospermum jasminoides are suitable for green façades in the Mediterranean climatic area during
winter. The use of the green façades allowed increasing the thermal performance of the walls during
night-time. They also reduced the surface temperature changes throughout the day
Thermal Behaviour Of Green Façades in Winter Climatic Conditions
Green infrastructures inside cities represent an effective strategy to face with the increasingly urgent environmental problems. Green systems applied to building envelope are among the most applicable
and useful solutions. These provide many significant advantages at different scales. Green façades (GF) are a typology of vertical green systems, applied to the vertical components of the building envelope. GF allow to save energy for air conditioning, by improving the envelope thermal performances. Energy behaviour of GF has been more deeply studied in warm periods, than in cold ones. This paper aims to analyse wintertime energy performances of GF. Evaluations were carried out based on the experimental data collected on two GF, in Bari (Italy), under Mediterranean climatic conditions. The experimental set-up included also a bare wall (BW), used as control. The heating effect provided by the greenery was pointed out through statistical and energy analyses. At night-time, the covered walls (CW) were warmer than the bare one up to 3.5°C. The dependence of night-time heating effect on microclimate parameters, as external air temperature, relative humidity and wind speed, was studied. External air temperature was found to be the most influencing factor: as it dropped, the heating effect increased. Overall energy transfer through the CW was lower than through the BW at night-time. The long-wave infrared energy radiative losses were reduced thanks to the green layer, which acted as a thermal barrier. These findings proved that GF improve winter night-time thermal performance by reducing energy losses
Hydrolyzed protein based materials for biodegradable spray mulching coatings
Low density polyethylene (LDPE) films are widespread used in agriculture
for soil mulching. The use of LDPE mulching films causes the serious drawback of
huge quantities of waste to be disposed of. Over the last years the growing
environmental awareness has been prompting the research to develop a new
generation of mulching products starting with raw materials from renewable origin.
These materials have to retain their physical and mechanical properties while in use
and have to be compostable or biodegradable at the end of their life, degrading via
micro-organisms into carbon dioxide or methane, water and biomass. The research
is focused on the development of novel biodegradable polymeric materials based on
hydrolyzed proteins, derived from waste products of the leather industry.
Biodegradable soil mulching coatings were realized with these biodegradable
polymeric materials by means of spray techniques; the coatings were tested in a
Ligustrum ovalifolium cultivation carried out inside a greenhouse. This paper
describes the functionalities of the new bio-based mulching coatings, which were
developed and tested in real scale greenhouse cultivation tests. During the trial, the
biodegradable soil mulching materials showed suitable properties for an efficient
and profitable use in agriculture. The innovative biodegradable spray coatings
lasted up to 18 months. The biodegradable materials could be the environmentally
friendly alternatives to synthetic petro-chemical polymers and could contribute to a
sustainable agriculture
Implementing a GIS-Based Digital Atlas of Agricultural Plastics to Reduce Their Environmental Footprint; Part I: A Deductive Approach
The agricultural sector has benefitted over the last century from several factors that have
led to an exponential increase in its productive efficiency. The increasing use of new materials, such
as plastics, has been one of the most important factors, as they have allowed for increased
production in a simpler and more economical way. Various polymer types are used in different
phases of the agricultural production cycle, but when their use is incorrectly managed, it can lead
to different environmental impacts. In this study, an applied and simplified methodology to manage
agricultural plastics monitoring and planning is proposed. The techniques used are based on
quantification through the use of different datasets (orthophotos and satellite images) of the areas
covered by plastics used for crop protection. The study area chosen is a part of the Ionian Coast of
Southern Italy, which includes the most important municipalities of the Basilicata Region for fruit
and vegetable production. The use of geographical techniques and observation methodologies,
developed in an open‐source GIS environment, enabled accurate location of about 2000 hectares of
agricultural land covered by plastics, as well as identification of the areas most susceptible to the
accumulation of plastic waste. The techniques and the model implemented, due to its simplicity of
use and reliability, can be applied by different local authorities in order to realize an Atlas of
agricultural plastics, which would be applied for continuous monitoring, thereby enabling the
upscaling of future social and ecological impact assessments, identification of new policy impacts,
market searches, etc
Effect of Leaf Area Index on Green Facade Thermal Performance in Buildings
Green facades applied on a building's envelope allow achieving the building's passive thermal control and energy consumption reduction. These are complex systems and many site- and plant-specific parameters influence their energy behavior. The leaf area index (LAI) is a relevant plant characteristic to consider. Solar shading and latent heat loss of plant evapotranspiration are the two main cooling mechanisms. The aim of this study was to assess the cooling effect provided by an evergreen south oriented green facade in summer in a Mediterranean area and to investigate what happens when LAI changes. Experimental data were used to calculate the cooling effect provided by the facade. Simulations with different LAI values were performed to determine the related cooling effect. The canopy solar transmissivity decreased by 54% for every LAI unit increase. LAI significantly influenced the green facade cooling performance. As LAI increased, solar shading and latent heat increased; this was relevant until an upper limit value of 6. An exponential equation to calculate the mean extinction coefficient (k(m)), and a polynomial relationship, with very good agreement, were proposed to calculate shading and latent heat as function of LAI. The findings of this research can effectively contribute to fill still existing gaps on green facades' energy performance and to the energy simulation of buildings equipped with them
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