Waste Management & Research: The Journal for a Sustainable Circular Economy, 2013
A review of agricultural plastic waste generation and consolidation in Europe is presented. A det... more A review of agricultural plastic waste generation and consolidation in Europe is presented. A detailed geographical mapping of the agricultural plastic use and waste generation in Europe was conducted focusing on areas of high concentration of agricultural plastics. Quantitative data and analysis of the agricultural plastic waste generation by category, geographical distribution and compositional range, and physical characteristics of the agricultural plastic waste per use and the temporal distribution of the waste generation are presented. Data were collected and cross-checked from a variety of sources, including European, national and regional services and organizations, local agronomists, retailers and farmers, importers and converters. Missing data were estimated indirectly based on the recorded cultivated areas and the characteristics of the agricultural plastics commonly used in the particular regions. The temporal distribution, the composition and physical characteristics of ...
This paper presents the second part of the results of detailed finite element analyses of three e... more This paper presents the second part of the results of detailed finite element analyses of three empty stiffened steel grain silos under nonuniform wind loading. In the present paper (part 2), the behaviour of the roof system is discussed, while in part 1, the behaviour of the stiffened silo wall was presented. The behaviour of the three silos analysed (tall, intermediate and shallow), depends on the geometry and the stiffening of the silo. The roof of the tall silo, reinforced with radial ribs only, develops stress resultants predominantly in the radial direction and transfers them to the centre collar and the wall in one-way bending. The roof systems of the larger diameter intermediate and shallow silos are reinforced with stiffeners and exhibit much more complicated behaviour. The stiffened roof shells of these latter two silos behave as continuous one-way slabs acting compositely with the rafters, with the purlins providing elastic support.
The term techno-economic sustainability assessment describes a methodology to assess the technica... more The term techno-economic sustainability assessment describes a methodology to assess the technical feasibility and economic sustainability of a process or a product. The methodology provides a set of sustainability principles to be fulfilled by the process or the product and develops a set of criteria and indicators to show how well these sustainability principles are fulfilled. To assess the techno-economic sustainability indicators, the process or product in question has to be optimised following system engineering and process design principles. The overall sustainability assessment of biobased products requires also the parallel environmental and social sustainability assessment. The chapter is modular, structured in three sections. In Section 1, The methodology for techno-economic sustainability assessment of resource efficiency and utilisation of renewable feedstock for the production of biobased products is presented and criteria and indicators are proposed for alternative feedstock. In Section 2, the methodology for techno-economic sustainability assessment of the conversion routes of renewable feedstock resources to biobased products is presented and criteria and indicators are proposed for alternative processing routes. In Section 3, the methodology for techno-economic sustainability assessment of the alternative End-of-Life routes for biobased products is presented and criteria and indicators are proposed for each major End-of-Life route.
Traditional farming systems are based on achieving high yields using high inputs, targeting accep... more Traditional farming systems are based on achieving high yields using high inputs, targeting acceptable farmers’ income. Nowadays, traditional farming shifts towards maximum possible crop yield using minimal inputs in an optimized way or towards organic farming, namely accomplishing low yield of high quality products without using conventional agrochemicals (i.e. fertilizers, pesticides). The last approach leads, in general, to lower energy consumption per unit area of land, therefore lower cost and lower greenhouse gas emissions (GHG). However, in a global perspective it has the risk of significant reduction in total production. Hence, it is vital to consider energy efficiency, namely the ratio between a unit of product and an input of energy, as a key comparison unit affecting the overall efficiency of crop farming systems in terms of energy and GHG emissions. In the present paper, two show cases of vineyard cultivations are presented to illustrate the energy efficiency and GHG emi...
Base anchorage forces for three empty, stiffened steel grain silos with conical roof shells are d... more Base anchorage forces for three empty, stiffened steel grain silos with conical roof shells are determined by finite element analysis for nonuniform wind loading. In general, the axial tensile forces govern for tall silos, while the shear force anchorage requirements control for shallow silos. The anchorage requirements for all three types of silos are adequately predicted by use of an adjusted membrane theory for a wind loaded cylindrical shell free at its top, with axial stress at the top due to the roof wind loading. The “cantilever beam” approximation yields extremely nonconservative anchorage forces.
Abstract Equilibrium modified atmosphere packaging (EMAP) is used for prolonging the shelf life o... more Abstract Equilibrium modified atmosphere packaging (EMAP) is used for prolonging the shelf life of fresh produce such as fruits and vegetables and preserving their quality characteristics such as freshness, colour and aroma. However, the resulting extensive use of plastic packaging films raises serious environmental concerns. Replacing conventional plastic films with novel biobased and biodegradable under composting conditions materials such as films made of poly-lactic acid (PLA), offers new sustainable solutions to the problem. In the present work, the gas transport properties of three layer PLA films have been studied in relation to their potential as EMA packaging materials for fresh produce. A simple one-dimensional model simulating the combined gas diffusion through micro-perforations and the permeable membrane was developed as a designing tool for PLA based EMA packaging systems. By using this model, innovative biodegradable bio-based EMAP systems were designed specifically for selected fruits and vegetables using laser microperforated, water vapour (WV) permeable PLA films. It was shown that the relatively high water vapour permeability of PLA films compared to conventional OPP films allows the development of an optimised biodegradable bio-based EMA packaging for the specific applications.
Porous panel Agricultural net Wind loads Wake flow The design and response of elastically support... more Porous panel Agricultural net Wind loads Wake flow The design and response of elastically supported short-length windbreak panels of different permeabilities under wind load is presented. The response of the panels was investigated through full-scale experiments and numerical simulation analysis. Two cladding materials were used: an impermeable film and a permeable net (62% porosity ratio). For the field experiments the elastic support of the panel was achieved by using extension springs which allowed it to pivot in response to wind loading through a hinge support at its base. The wind pressures developed on the panel for various equilibrium positions reached under different wind velocities were measured. The elastic support response resulted in a significant reduction of the wind pressures and the stress resultants on the windbreak for both cladding materials. A combined model coupling twodimensional computational fluid dynamic simulation and non-linear structural analysis was used to analyse the behaviour of the elastically supported panel when interacting with the wind. The numerical results for the elastic support response under wind load, and the developed wind pressures, were found to agree with the full-scale experiments for both cladding cases. For the permeable cladding case, the wake flow of the elastically supported panel was shown to be free of large scale turbulent eddies when analysed by numerical simulations. The wake airflow for the impermeable panel case was found to be complex and extensive investigation is required.
Agricultural nets are extensively used in certain types of cultivation, such as fruit-tree farmin... more Agricultural nets are extensively used in certain types of cultivation, such as fruit-tree farming, for protection against birds and insects as well as anti-hail and anti-frost shields or windbreaks. However, the design, quality assessment and use of the agricultural nets are more or less empirical. In the present paper, the most critical properties of the nets with regard to the agricultural applications are determined. Proper evaluation schemes for the most critical mechanical properties of permeable materials, directly related to the needs of the specific agricultural applications, are established. The results of the adaptation of existing testing methods designed for measuring selected mechanical properties of agricultural nets are presented along with specific technical recommendations. This pre-normative research work may support future conormative work for the establishment of European standards for measuring the mechanical properties of agricultural nets.
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy An experimental helical-tubular photobioreactor for continuous production of Nannochloropsis sp.
The main objectives of a new European Thematic Network entitled 'Education and Research in B... more The main objectives of a new European Thematic Network entitled 'Education and Research in Biosystems Engineering in Europe (ERABEE-TN)' is to initiate and contribute to the structural development and the assurance of the quality assessment of the emerging discipline of Biosystems Engineering in Europe. To date, very few Biosystems Engineering programs exist in Europe and those that are initiated are at a very primitive stage of development. The innovative and novel goal of the Thematic Network is to promote this critical transition, which requires major restructuring in Europe, exploiting along this direction the outcomes accomplished by its predecessor; the USAEE-TN (University Studies in Agricultural Engineering in Europe). It also aims at enhancing the compatibility among the new programmes of Biosystems Engineering, aiding their recognition and accreditation at European and International level and facilitating greater mobility of skilled personnel, researchers and stu...
The accumulation of plastic wastes in the marine environment represents a steadily increasing glo... more The accumulation of plastic wastes in the marine environment represents a steadily increasing global environmental threat. The replacement of conventional plastics with bio-based biodegradable materials may contribute to alleviating the problem in the long run. This work studies the disintegration behaviour of three bio-based plastic materials, namely Polyhydroxybutyrate (PHB), Polybutylene sebacate (PBSe), Polybutylene sebacate-co-terephthalate (PBSeT), in three different coastal zone marine environments under natural conditions. The three studied environments were: 1) the seashore zone which is periodically covered by the seawater due to waves or tide, called eulittoral or intertidal zone; 2) the water column zone of small depth (about 10 m), called pelagic zone; and 3) the interface zone between the water column and the seabed sediment at small depth (about 20 m), called sublittoral or benthic zone. The experiments took place in the Aegean Sea at the SW coast of Salamis Island. The results showed that disintegration, as an indicative measure of biodegradation, occurs in all three tested environments, even though the rate depends on the material, the habitat, and the prevailing during the testing period environmental conditions. The degrees of disintegration of all materials in the three environments exhibited significant differences: Benthic > Intertidal > Pelagic. The observed disintegration can be attributed to biodegradation since the negative reference Low-density Polyethylene (LLDPE) material did not disintegrate.
Waste Management & Research: The Journal for a Sustainable Circular Economy, 2013
A review of agricultural plastic waste generation and consolidation in Europe is presented. A det... more A review of agricultural plastic waste generation and consolidation in Europe is presented. A detailed geographical mapping of the agricultural plastic use and waste generation in Europe was conducted focusing on areas of high concentration of agricultural plastics. Quantitative data and analysis of the agricultural plastic waste generation by category, geographical distribution and compositional range, and physical characteristics of the agricultural plastic waste per use and the temporal distribution of the waste generation are presented. Data were collected and cross-checked from a variety of sources, including European, national and regional services and organizations, local agronomists, retailers and farmers, importers and converters. Missing data were estimated indirectly based on the recorded cultivated areas and the characteristics of the agricultural plastics commonly used in the particular regions. The temporal distribution, the composition and physical characteristics of ...
This paper presents the second part of the results of detailed finite element analyses of three e... more This paper presents the second part of the results of detailed finite element analyses of three empty stiffened steel grain silos under nonuniform wind loading. In the present paper (part 2), the behaviour of the roof system is discussed, while in part 1, the behaviour of the stiffened silo wall was presented. The behaviour of the three silos analysed (tall, intermediate and shallow), depends on the geometry and the stiffening of the silo. The roof of the tall silo, reinforced with radial ribs only, develops stress resultants predominantly in the radial direction and transfers them to the centre collar and the wall in one-way bending. The roof systems of the larger diameter intermediate and shallow silos are reinforced with stiffeners and exhibit much more complicated behaviour. The stiffened roof shells of these latter two silos behave as continuous one-way slabs acting compositely with the rafters, with the purlins providing elastic support.
The term techno-economic sustainability assessment describes a methodology to assess the technica... more The term techno-economic sustainability assessment describes a methodology to assess the technical feasibility and economic sustainability of a process or a product. The methodology provides a set of sustainability principles to be fulfilled by the process or the product and develops a set of criteria and indicators to show how well these sustainability principles are fulfilled. To assess the techno-economic sustainability indicators, the process or product in question has to be optimised following system engineering and process design principles. The overall sustainability assessment of biobased products requires also the parallel environmental and social sustainability assessment. The chapter is modular, structured in three sections. In Section 1, The methodology for techno-economic sustainability assessment of resource efficiency and utilisation of renewable feedstock for the production of biobased products is presented and criteria and indicators are proposed for alternative feedstock. In Section 2, the methodology for techno-economic sustainability assessment of the conversion routes of renewable feedstock resources to biobased products is presented and criteria and indicators are proposed for alternative processing routes. In Section 3, the methodology for techno-economic sustainability assessment of the alternative End-of-Life routes for biobased products is presented and criteria and indicators are proposed for each major End-of-Life route.
Traditional farming systems are based on achieving high yields using high inputs, targeting accep... more Traditional farming systems are based on achieving high yields using high inputs, targeting acceptable farmers’ income. Nowadays, traditional farming shifts towards maximum possible crop yield using minimal inputs in an optimized way or towards organic farming, namely accomplishing low yield of high quality products without using conventional agrochemicals (i.e. fertilizers, pesticides). The last approach leads, in general, to lower energy consumption per unit area of land, therefore lower cost and lower greenhouse gas emissions (GHG). However, in a global perspective it has the risk of significant reduction in total production. Hence, it is vital to consider energy efficiency, namely the ratio between a unit of product and an input of energy, as a key comparison unit affecting the overall efficiency of crop farming systems in terms of energy and GHG emissions. In the present paper, two show cases of vineyard cultivations are presented to illustrate the energy efficiency and GHG emi...
Base anchorage forces for three empty, stiffened steel grain silos with conical roof shells are d... more Base anchorage forces for three empty, stiffened steel grain silos with conical roof shells are determined by finite element analysis for nonuniform wind loading. In general, the axial tensile forces govern for tall silos, while the shear force anchorage requirements control for shallow silos. The anchorage requirements for all three types of silos are adequately predicted by use of an adjusted membrane theory for a wind loaded cylindrical shell free at its top, with axial stress at the top due to the roof wind loading. The “cantilever beam” approximation yields extremely nonconservative anchorage forces.
Abstract Equilibrium modified atmosphere packaging (EMAP) is used for prolonging the shelf life o... more Abstract Equilibrium modified atmosphere packaging (EMAP) is used for prolonging the shelf life of fresh produce such as fruits and vegetables and preserving their quality characteristics such as freshness, colour and aroma. However, the resulting extensive use of plastic packaging films raises serious environmental concerns. Replacing conventional plastic films with novel biobased and biodegradable under composting conditions materials such as films made of poly-lactic acid (PLA), offers new sustainable solutions to the problem. In the present work, the gas transport properties of three layer PLA films have been studied in relation to their potential as EMA packaging materials for fresh produce. A simple one-dimensional model simulating the combined gas diffusion through micro-perforations and the permeable membrane was developed as a designing tool for PLA based EMA packaging systems. By using this model, innovative biodegradable bio-based EMAP systems were designed specifically for selected fruits and vegetables using laser microperforated, water vapour (WV) permeable PLA films. It was shown that the relatively high water vapour permeability of PLA films compared to conventional OPP films allows the development of an optimised biodegradable bio-based EMA packaging for the specific applications.
Porous panel Agricultural net Wind loads Wake flow The design and response of elastically support... more Porous panel Agricultural net Wind loads Wake flow The design and response of elastically supported short-length windbreak panels of different permeabilities under wind load is presented. The response of the panels was investigated through full-scale experiments and numerical simulation analysis. Two cladding materials were used: an impermeable film and a permeable net (62% porosity ratio). For the field experiments the elastic support of the panel was achieved by using extension springs which allowed it to pivot in response to wind loading through a hinge support at its base. The wind pressures developed on the panel for various equilibrium positions reached under different wind velocities were measured. The elastic support response resulted in a significant reduction of the wind pressures and the stress resultants on the windbreak for both cladding materials. A combined model coupling twodimensional computational fluid dynamic simulation and non-linear structural analysis was used to analyse the behaviour of the elastically supported panel when interacting with the wind. The numerical results for the elastic support response under wind load, and the developed wind pressures, were found to agree with the full-scale experiments for both cladding cases. For the permeable cladding case, the wake flow of the elastically supported panel was shown to be free of large scale turbulent eddies when analysed by numerical simulations. The wake airflow for the impermeable panel case was found to be complex and extensive investigation is required.
Agricultural nets are extensively used in certain types of cultivation, such as fruit-tree farmin... more Agricultural nets are extensively used in certain types of cultivation, such as fruit-tree farming, for protection against birds and insects as well as anti-hail and anti-frost shields or windbreaks. However, the design, quality assessment and use of the agricultural nets are more or less empirical. In the present paper, the most critical properties of the nets with regard to the agricultural applications are determined. Proper evaluation schemes for the most critical mechanical properties of permeable materials, directly related to the needs of the specific agricultural applications, are established. The results of the adaptation of existing testing methods designed for measuring selected mechanical properties of agricultural nets are presented along with specific technical recommendations. This pre-normative research work may support future conormative work for the establishment of European standards for measuring the mechanical properties of agricultural nets.
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy An experimental helical-tubular photobioreactor for continuous production of Nannochloropsis sp.
The main objectives of a new European Thematic Network entitled 'Education and Research in B... more The main objectives of a new European Thematic Network entitled 'Education and Research in Biosystems Engineering in Europe (ERABEE-TN)' is to initiate and contribute to the structural development and the assurance of the quality assessment of the emerging discipline of Biosystems Engineering in Europe. To date, very few Biosystems Engineering programs exist in Europe and those that are initiated are at a very primitive stage of development. The innovative and novel goal of the Thematic Network is to promote this critical transition, which requires major restructuring in Europe, exploiting along this direction the outcomes accomplished by its predecessor; the USAEE-TN (University Studies in Agricultural Engineering in Europe). It also aims at enhancing the compatibility among the new programmes of Biosystems Engineering, aiding their recognition and accreditation at European and International level and facilitating greater mobility of skilled personnel, researchers and stu...
The accumulation of plastic wastes in the marine environment represents a steadily increasing glo... more The accumulation of plastic wastes in the marine environment represents a steadily increasing global environmental threat. The replacement of conventional plastics with bio-based biodegradable materials may contribute to alleviating the problem in the long run. This work studies the disintegration behaviour of three bio-based plastic materials, namely Polyhydroxybutyrate (PHB), Polybutylene sebacate (PBSe), Polybutylene sebacate-co-terephthalate (PBSeT), in three different coastal zone marine environments under natural conditions. The three studied environments were: 1) the seashore zone which is periodically covered by the seawater due to waves or tide, called eulittoral or intertidal zone; 2) the water column zone of small depth (about 10 m), called pelagic zone; and 3) the interface zone between the water column and the seabed sediment at small depth (about 20 m), called sublittoral or benthic zone. The experiments took place in the Aegean Sea at the SW coast of Salamis Island. The results showed that disintegration, as an indicative measure of biodegradation, occurs in all three tested environments, even though the rate depends on the material, the habitat, and the prevailing during the testing period environmental conditions. The degrees of disintegration of all materials in the three environments exhibited significant differences: Benthic > Intertidal > Pelagic. The observed disintegration can be attributed to biodegradation since the negative reference Low-density Polyethylene (LLDPE) material did not disintegrate.
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