The Greek Unions of Agricultural Cooperatives as efficient enterprises

This paper investigates the efficiency level of Unions of Agricultural Cooperatives (UAC) and Investor-Oriented Firms (IOF) in Greece. Data have been collected over a period of six years for UAC (1995-2000) and of five years for IOF (1995-1999). Financial analysis results were used with the help of 3SLS technique in a four equation simultaneous model in order to estimate those parameters, which would determine the efficiency level of the UAC and the IOF in Greece.agricultural cooperatives, investor-oriented firms, efficiency, simultaneous equations, Industrial Organization,

Experimental and numerical studies on the flow characteristics and separation properties of dispersed liquid-liquid flows

© 2019 Author(s). The local dynamics of spatially developing liquid-liquid dispersed flows at low superficial velocities, ranging from 0.2 to 0.8 m s-1, are investigated. The dispersions are generated with an in-line static mixer. Detailed measurements with laser-based diagnostic tools are conducted at two axial pipe locations downstream of the mixer, namely, at 15 and 135 equivalent pipe diameters. Different flow patterns are recorded, and their development along the streamwise direction is shown to depend on the initial size and concentration of the drops as well as the mixture velocity. The drop size is accurately predicted by an empirical formula. The variations in drop concentration over the pipe cross-section along the pipe result in local changes of the physical properties of the mixture and consequently in asymmetrical velocity profiles, with the maxima of the velocity located in the drop-free region. Computational fluid dynamics simulations based on a mixture approach predict the experimental results close to the experimental uncertainties for the majority of the cases. The simulation results reveal that gravity and lift forces, as well as shear-induced diffusion are the most important mechanisms affecting the drop migration. It is found that the drops behave as suspensions of rigid spheres for the conditions investigated, despite the deformation effects, which are found experimentally to be stronger at the densely packed region

Solution-processed CuIn(S,Se)2 absorber layers for application in thin film solar cells

A pure solution-based approach is proposed for the fabrication of high quality CuIn(S,Se)2 (CIS) thin films. This is an alternative procedure to the hydrazine-based route and involves the dissolution of metal chalcogenides in a safer solvent combination. The solvent mixture used in this work has the same advantages as hydrazine, such as good solubility of metal chalcogenides and clean decomposition, which is a prerequisite for high quality absorber layers. The solvents that are used are also much less toxic compared to hydrazine and can potentially result in a more feasibly industrially scalable deposition technology for CIS and the related alloys including Cu(In,Ga)(S,Se)2 (CIGS). The characterization of the obtained thin film material verifies the presence of the CIS chalcopyrite phase with good crystal growth

Enabling Sustainable Freight Air Transport in the Adriatic Region through Development of ICT Platform

Freight transport in the Adriatic area suffers from persistent organizational, operational and service barriers and the negative impacts of road transport. Multimodal interventions could reduce CO2 emissions and other impacts, including air and noise pollution, and road congestion. Integrated sustainable solutions can act to improve traffic flow and logistics, and management of goods and tourism supply. Multimodal optimization of road-sea combined transport can be augmented to include air modal share on existing and new routes for sensitive freight with emphasis on yearlong operations. This paper adresses the need to improve and extend the availability of passenger routes to allow the potential for mixed cargo in the Adriatic with a case study in Italy-Greece transport. Such plans are hampered by the overlong (up to 15 hours) duration of air trips, which could reduce product quality within a few hours after harvest. Fast shipment and delivery of affordable fresh products, such as mozzarella and strawberries is essential, and would benefit from nonused passenger cargo. Fresh products could use available hold space, guaranteeing lower-than-conventional shipping time at affordable price. The new service would establish new shipping options for fresh products, empowering Italian and Greek local producers. The service will be enabled through an integrated ICT platform that was developed to offer user access (e.g. to information on departure time, load space availability, goods allowed for transportation), and facilitate creation of new market opportunities for fresh producers. The platform supports the identification of demand and supply (by creating accounts as seller or buyer) and the booking of transport. The platform end user (seller or buyer) can find the proper passenger carrier for shipping fresh products to the airport of origin. Platform design includes Operational (OR) and NonOperational (NOR) requirements. For assuring traceability and location information, static and dynamic RFID tags and portable RFID readers, as well as GPS devices and/or tracking smartphones and supporting infrastructure were included

Women Scientists Who Made Nuclear Astrophysics

Female role models reduce the impact on women of stereotype threat, i.e., of being at risk of conforming to a negative stereotype about one's social, gender, or racial group [1,2]. This can lead women scientists to underperform or to leave their scientific career because of negative stereotypes such as, not being as talented or as interested in science as men. Sadly, history rarely provides role models for women scientists; instead, it often renders these women invisible [3]. In response to this situation, we present a selection of twelve outstanding women who helped to develop nuclear astrophysics

Kaluza-Klein Induced Gravity Inflation

A D-dimensional induced gravity theory is studied carefully in a $4 + (D-4)$ dimensional Friedmann-Robertson-Walker space-time. We try to extract information of the symmetry breaking potential in search of an inflationary solution with non-expanding internal-space. We find that the induced gravity model imposes strong constraints on the form of symmetry breaking potential in order to generate an acceptable inflationary universe. These constraints are analyzed carefully in this paper.Comment: 10 pages, title changed, corrected some typos, two additional comments adde

Brane Decay of a (4+n)-Dimensional Rotating Black Hole. III: spin-1/2 particles

In this work, we have continued the study of the Hawking radiation on the brane from a higher-dimensional rotating black hole by investigating the emission of fermionic modes. A comprehensive analysis is performed that leads to the particle, power and angular momentum emission rates, and sheds light on their dependence on fundamental parameters of the theory, such as the spacetime dimension and angular momentum of the black hole. In addition, the angular distribution of the emitted modes, in terms of the number of particles and energy, is thoroughly studied. Our results are valid for arbitrary values of the energy of the emitted particles, dimension of spacetime and angular momentum of the black hole, and complement previous results on the emission of brane-localised scalars and gauge bosons.Comment: Latex file, JHEP style, 34 pages, 16 figures Energy range in plots increased, minor changes, version published in JHE

Brane decay of a (4+n)-dimensional rotating black hole: spin-0 particles

In this work, we study the `scalar channel' of the emission of Hawking radiation from a (4+n)-dimensional, rotating black hole on the brane. We numerically solve both the radial and angular part of the equation of motion for the scalar field, and determine the exact values of the absorption probability and of the spheroidal harmonics, respectively. With these, we calculate the particle, energy and angular momentum emission rates, as well as the angular variation in the flux and power spectra -- a distinctive feature of emission during the spin-down phase of the life of the produced black hole. Our analysis is free from any approximations, with our results being valid for arbitrarily large values of the energy of the emitted particle, angular momentum of the black hole and dimensionality of spacetime. We finally compute the total emissivities for the number of particles, energy and angular momentum and compare their relative behaviour for different values of the parameters of the theory.Comment: 24 pages, 13 figure

(De)Stabilization of an extra dimension due to a Casimir force

We study the stabilization of one spatial dimension in (p+1+1)-dimensional spacetime in the presence of $p$-dimensional brane(s), a bulk cosmological constant and the Casimir force generated by a conformally coupled scalar field. We find general static solutions to the metric which require the fine-tuning of the inter-brane distance and the bulk cosmological constant (leaving the two brane tensions as free parameters) corresponding to a vanishing effective cosmological constant and a constant radion field. Taking these solutions as a background configuration, we perform a dimensional reduction and study the effective theory in the case of one- and two-brane configurations. We show that the radion field can have a positive mass squared, which corresponds to a stabilization of the extra dimension, only for a repulsive nature of the Casimir force. This type of solution requires the presence of a negative tension brane. The solutions with one or two positive tension branes arising in this theory turn out to have negative radion mass squared, and therefore are not stable.Comment: new references added, version published in PR

Habitat Selection and Temporal Abundance Fluctuations of Demersal Cartilaginous Species in the Aegean Sea (Eastern Mediterranean)

Predicting the occurrence of keystone top predators in a multispecies marine environment, such as the Mediterranean Sea, can be of considerable value to the long-term sustainable development of the fishing industry and to the protection of biodiversity. We analysed fisheries independent scientific bottom trawl survey data of two of the most abundant cartilaginous fish species (Scyliorhinus canicula, Raja clavata) in the Aegean Sea covering an 11-year sampling period. The current findings revealed a declining trend in R. clavata and S. canicula abundance from the late ′90 s until 2004. Habitats with the higher probability of finding cartilaginous fish present were those located in intermediate waters (depth: 200–400 m). The present results also indicated a preferential species' clustering in specific geographic and bathymetric regions of the Aegean Sea. Depth appeared to be one of the key determining factors for the selection of habitats for all species examined. With cartilaginous fish species being among the more biologically sensitive fish species taken in European marine fisheries, our findings, which are based on a standardized scientific survey, can contribute to the rational exploitation and management of their stocks by providing important information on temporal abundance trends and habitat preferences