This paper applied a non-parametric (Data Envelopment Analysis) method to analyze the efficiency of farmers, discriminate efficient farmers from inefficient ones and to identify wasteful uses of energy in order to optimize the energy inputs for greenhouse cucumber production in Lorestan province of Iran. Data were collected from 27 cucumber producers by using a face-to-face questionnaire.DEA cr...

The effectiveness of inundative releases of the parasitoid Encarsia formosa for control of Bemisia argentifolii on poinsettia was determined in replicated experimental greenhouses. We evaluated two release rates of E. formosa: a low release rate (1 wasp/plant/week, released in two greenhouses, in spring 1995) and a high release rate (3 wasps/plant/week, released in two greenhouses, in fall 1993...

This study describes the simulation of gas demand for greenhouses in the agricultural area. Using the data provided by an energy company providing gas to over 3600 individual greenhouses , several models are developed to predict the gas demand of an individual green house. Using these models peak smoothing strategies for the overall gas demand can be developed and tested. Three of such peak smo...

A major challenge of designing a bioregenerative life support system for Mars is the reduction of the mass, volume, power, thermal and crew-time requirements. Structural mass of the greenhouse could be saved by operating the greenhouse at low atmospheric pressure. This paper investigates the feasibility of this concept. The method of equivalent system mass is used to compare greenhouses operate...

To analyze the effect of stressed skin action of rigid plate covering on anti-collapse behavior of solar greenhouses under snow load, the numerical simulation on the overall collapse process of single skeleton structure and 6skeleton overall spatial structure with rigid plate covering were conducted on ANSYS. The collapse modes of solar greenhouses and snow load-displacement curves were obtaine...

A (semi-)closed greenhouse is a novel greenhouse with an active cooling system and temporary heat storage in an aquifer. Air is cooled, heated and dehumidified by air treatment units. Climate in (semi-)closed greenhouses differs from that of conventional open greenhouses. The aims of our research were first, to analyze the effect of active cooling on greenhouse climate, in terms of stability, g...

Due to the randomicity of the natural growth of tomatoes in greenhouses and different storage days for market needs, it is difficult to find appropriate methodologies for certain ripe-tomato-harvesting robot systems. This paper proposes a novel approach for recognizing ripe tomatoes from the natural background in greenhouses and extracting abscission points after color segmentation for autonomo...

Mediterranean countries offer very favorable climatic conditions for growing plants in a protected environment: as a matter of fact, the high solar radiation allows the use of greenhouses with simple structures, covered with plastic film and without fixed installations for winter heating. They are called “Mediterranean greenhouses” and are totally different from those in Central and Northern Eu...

Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of colle...