Search results for "efficiency"
showing 10 items of 1430 documents
Mechanical efficiency of locomotion in females during different kinds of muscle action
1990
The mechanical efficiencies (ME) of pure positive and pure negative work as well as of stretch-shortening cycle (SSC) exercise were investigated with a special sledge apparatus. The subjects were 20 young females who performed six different types of submaximal exercise: two of pure concentric exercise (positive work), two of pure eccentric exercise (negative work) and two SSC exercises. The work intensities were determined individually, from the recordings of distance obtained during a single maximal concentric exercise. Each exercise involved 60 muscle actions lasting a total of 3 min per testing condition. The MEs of pure positive work with intensities of 30% and 60% maximum (C30 and C60 …
Mechanical efficiency in athletes during running.
2007
The purpose of this study was to compare the external mechanical efficiency (ME) between power-trained athletes (n = 5) and endurance-trained athletes (n = 5). The relationships between biomechanical variables and metabolic cost were also investigated. The subjects ran at 3 different speeds (2.50 m.s-1, 3.25 m.s-1 and 4.00 m.s-1) both on the treadmill and on the track. The external work of the subjects was determined by a kinematic arm, and energy expenditure was determined by measuring oxygen consumption and respiratory exchange ratio. Biomechanical parameters included ground reaction forces, angular displacements of the knee and ankle joints and electromyography (EMG) of the selected musc…
Effect of biomass features on oxygen transfer in conventional activated sludge and membrane bioreactor systems
2019
Abstract The aim of the present study was to compare the oxygen transfer efficiency in a conventional activated sludge and a membrane bioreactor system. The oxygen transfer was evaluated by means of the oxygen transfer coefficient and α-factor calculation, under different total suspended solids concentration, extracellular polymeric substances, sludge apparent viscosity and size of the flocs. The oxygen transfer coefficient and α-factor showed an exponential decreasing trend with total suspended solid, with a stronger oxygen transfer coefficient dependence in the conventional activated sludge compared to the membrane bioreactor. It was noted that the oxygen transfer coefficient in the conve…
Cost and Financing of Education and its Impact on Coverage and Quality of Services and Efficiency and Equity in Sub-Saharan African Countries
2007
07052; In this chapter, we take mostly an international comparative perspective limited to Sub-Saharan African countries. First, we analyse first the macro picture and the public finance dimension, analyzing the systemic choices made in the distribution of public resources across levels and types of education. Second, we move to unit cost estimates and the factors accounting for their level in a given country and to their variation across the different countries of the region. Finally, we examine the implication of the choices made in the financial dimension upon outcomes (coverage and quality of educationl services), birnging issues of efficiency and equity into the analysis.
Assessing the impact of agri-environmental schemes on the eco-efficiency of rain-fed agriculture
2012
This paper analyses the impact of the Agri-environmental Extensification Scheme for the Protection of Flora and Fauna (F&F Scheme) on the eco-efficiency of a sample of dryland farms in the Spanish region of Castile and Leon. Using Data Envelopment Analysis (DEA) and the so-called program decomposition approach to efficiency measurement, we explore whether or not the production technology of the farms included in the F&F Scheme is more eco-efficient than the technology used by farms that are not included in the Scheme. The re-sults obtained confirm the foregoing hypothesis, providing evidence that environmental pres-sures could be reduced if all farms adopted the F&F Scheme technology. Furth…
Climate variability and agriculture in Italy: a stochastic frontier analysis at the regional level
2020
In the next future, climate change effects will represent a challenge for Europe and the Mediterranean area. These will have to cope with a rapid increase in climate variability. Although many economic sectors may be affected, agriculture is the most susceptible as climate heavily affects crop production trends, yield variability and the availability of areas suitable for cultivation. Using the stochastic frontier approach, the aim of this work is to analyse the impacts of climate variability on Italian regional technical efficiency in the agricultural sector for a period spanning from 2000 to 2009. Considering that technical inefficiency could be influenced by two main annual meteorologica…
Le filiere del sistema agricolo per l'energia e l'efficienza energetica
2011
Increasing the use of renewable energies and Energy Efficiency offer significant opportunities for Italy to reduce fossil energy, greenhouse gas emissions and secure its energy supply. This report presents a brief analysis of the most important supply chains of the Agriculture system. Greatest attention is paid to the significant role that agriculture and its supply chains are likely to play in terms of bioenergy production and energy saving. Special attention is devoted to new agricultural activities like those associated with the reduction of vegetable food waste, the agrotourism, the urban agriculture, the plastic coverings and the greenhouses, the plant protection and the fertilizers. D…
Energy use efficiency of livestock farms in a mountain area of Sicily
2009
The research aimed to evaluate the performance (in terms of energy) of livestock farms located in a Mediterranean mountain area and characterized by different stocking rates. Farm data were collected from in-person interviews of farmers of 58 farms representative of the livestock farms of the Madonie and Nebrodi mountains area (Sicily, Italy), including several parameters related to farm characteristics, animal, crop and pasture management. The farm parameters were used to calculate input and output energy values from which agroecosystem performance indicators were derived. Increasing stocking rate corresponded to a more than proportional increase in total inputs per unit area because of a …
Cover crop management and water conservation in vineyard and olive orchards
2021
Abstract Sustainability in orchard crops is an important goal for farmers, decision-makers and consumers. The United Nations Sustainable Development Goals emphasize the importance of the soils in the Earth System to achieve sustainability and accomplish the Land Degradation Neutrality Challenge. Within the world agriculture land, olive and vineyards are within the eldest crops in the world, and they are also the ones with the highest degree of soil degradation. Cover crops (CC) are widely accepted as sustainable crop management that reduces soil and water losses, restores organic matter, increases biodiversity and fertility in degraded agriculture soils. The agriculture land must shift into…
Researches on the Alternative Fuels Which Can Be Used to Motors
2010
The alternative fuels are substances or materials used as fuel, other than the old conventional fuels (oil, natural gases and coals). 
 The paper analyses the most important alternative fuels, such as: bio-diesel, alcohols and hydrogen, presenting at each category the main important characteristics, the advantages and disadvantages presented by them. 
 The methyl-ester which is known as bio-diesel can be used in all motors with ignition by compression, alone or mixed in any proportion with oil, with minor modifications at the injection system. Bio-diesel fuel assures the same motor power as oil does, having even a bigger cetanic number than the usual oil. After tests, it was obser…