Showing papers by "Demetres Briassoulis published in 2011"
TL;DR: Comparison studies between the biodegradation in soil behaviour of two important biodegradable polymers based on renewable resources: poly(lactic acid) (PLA) versus polyhydroxyalkanoates (PHA).
Abstract: This work presents the last phase of long-term experimental studies on the biodegradation in soil behaviour of polymers destined for agricultural applications. The paper focuses on comparative studies between the biodegradation in soil behaviour of two important biodegradable polymers based on renewable resources: poly(lactic acid) (PLA) versus polyhydroxyalkanoates (PHA). Full-scale experiments were carried out during the period June 2008–January 2009. Different methods of exposure were applied in the case of polyhydroxyalkanoates, simulating the agricultural biodegradable mulching films use and their fate in soil after the end of their useful lifetime. The field results were compared with the results of biodegradation under controlled laboratory conditions simulating biodegradation in soil, using soil from the experimental field. Further, the field results were compared against the results of biodegradation under farm composting conditions.
109 citations
TL;DR: In this paper, an experimental investigation has been carried out focusing on the combined effects of critical factors on the controlled photo-chemical degradation of photodegradable mulching LLDPE films with pro-oxidants and the behaviour of their remains in the soil.
55 citations
TL;DR: In this paper, the field performance of experimental biodegradable drip irrigation thin wall and regular pipes was investigated through three sets of full-scale experiments and in the laboratory and the results showed that the tensile strength of the Mater-Bi and Bioflex thin wall pipes remained almost constant during the total exposure time, except from the folding areas.
Abstract: The field performance of experimental biodegradable drip irrigation thin wall and regular pipes was investigated through three sets of full-scale experiments and in the laboratory. These experimental biodegradable drip irrigation systems were produced through the processing of biodegradable under real soil conditions polymers, Mater-Bi and Bioflex. The mechanical behaviour of the biodegradable thin wall pipes during the irrigation period was more unstable when compared to the corresponding behaviour of the rigid pipes. The tensile strength of the Mater-Bi and Bioflex thin wall pipes remained almost constant during the total exposure time, except from the folding areas. During the first 7–23 days of exposure in the field, the thin wall pipes had already lost more than the 50% of their initial elongation at break value due to degradation. However, their hydraulic performance began to decline only after a period of 100–120 days with the simultaneous formation of the first cracks. Likewise, the majority of the series of biodegradable rigid pipes exhibited a remarkable reduction in their elongation at break values in the transverse direction within the first 2 weeks. Despite the significant drop of the elongation at break, all biodegradable rigid pipes generally retained their tensile strength as well as a satisfactory hydraulic performance during almost the whole duration of their exposure. A few premature leakages in some points adjoining the drippers were observed after 8–10 weeks of exposure.
21 citations
TL;DR: In this article, the first experimental biodegradable drip irrigation thin wall pipes and pipes were produced for experimental purposes, and the results of a research work investigating the possibilities and limitations in developing biodesgradable drippers and pipes are presented.
Abstract: The increased cost associated with the waste removal and disposal of conventional agricultural plastic in contact with the soil combined with the gradually decreasing cost of the biodegradable plastics allowed the commercialization of biodegradable mulching films. Since the conventional thin wall or tape drip irrigation system lies under the mulching film and is used for one season only, it would be desirable to replace it with a biodegradable one. This paper presents the results of a research work investigating the possibilities and limitations in developing biodegradable drip irrigation thin wall pipes and pipes. The first ever experimental biodegradable drip irrigation thin wall pipes were produced. Rigid pipes were also produced for experimental purposes. Manufacturing problems were encountered in the processing of the biodegradable drippers and irrigation thin wall pipes with the experimental materials due to the complex formulation of the raw materials and the fact that the machinery used was specifically designed for PE processing. Experimental biodegradable thin wall pipes made of Bioflex with embedded drippers made of Mater-Bi were produced. The processing problems encountered with the production of thin wall pipes were surpassed during the experimental production of rigid type irrigation pipes. A biodegradable rigid irrigation pipe made of a grade of Mater-Bi, with embedded cylindrical drippers made of another grade of Mater-Bi was produced successfully. A better understanding of the thermal profile of the biodegradable raw materials and the use of processing equipment adapted to this profile might allow in the future the manufacturing of thin wall drip irrigation pipes for agricultural applications, and the use of alternative biodegradable materials.
15 citations
01 Jan 2011
TL;DR: The ERABEE Thematic Network as mentioned in this paper was a follow-up of a previous thematic network called USAEE (University Studies of Agricultural Engineering in Europe) and both were co-financed by the European Community in the framework of the LLP Programme (Lifelong Learning Programme).
Abstract: This paper describes the main result produced by the ERABEE (Education & Research in Biosystems Engineering in Europe) Thematic Network. The ERABEE Thematic Network was a follow-up of a previous Thematic Network called USAEE (University Studies of Agricultural Engineering in Europe) and both were co-financed by the European Community in the framework of the LLP Programme (Lifelong Learning Programme). The innovative and novel goal of the ERABEE Network was to promote the critical and inevitable transition from the traditional discipline of Agricultural Engineering to the emerging discipline of Biosystems Engineering, exploiting along this direction the outcomes accomplished by the earlier USAEE Thematic Network. It also aimed at enhancing the compatibility among the new programmes of Biosystems Engineering, supporting their recognition and accreditation at European and International level and facilitating greater mobility of skilled personnel, researchers and students.
2 citations
26 Jun 2011
TL;DR: Wolfe as mentioned in this paper is a Fellow of ASABE, the American Institute for Medical and Biological Engineers (AIMBE), and ABET, Inc. She is active in the American Society of Agricultural Engineers, including two terms on the Board of Directors/Trustees and in leadership roles on technical committees.
Abstract: Dr. Mary Leigh Wolfe is Professor and Interim Head in the Department of Biological Systems Engineering (BSE) at Virginia Tech. Dr. Wolfe conducts research and teaches undergraduate and graduate courses focused on hydrologic modeling, nonpoint source (NPS) pollution control strategies, and decision support tools for NPS pollution control and watershed management. She is active in the American Society of Agricultural Engineers, including two terms on the Board of Directors/Trustees and in leadership roles on technical committees. She is currently serving on the ASABE Foundation Board of Directors. Dr. Wolfe has been very active in accreditation of engineering educational programs, including serving as chair of the Engineering Accreditation Commission of ABET, Inc. for the 2007-08 accreditation cycle. Dr. Wolfe is a Fellow of ASABE, the American Institute for Medical and Biological Engineers (AIMBE), and ABET, Inc.
2 citations