Search results for "efficiency"
showing 10 items of 1430 documents
Effects of Biochar on Irrigation Management and Water Use Efficiency for Three Different Crops in a Desert Sandy Soil
2020
This paper aimed at investigating if the application of biochar (BC) to desert sand (DS) from the United Arab Emirates (UAE), characterized by a very poor soil-water retention (SWR) and by a very low value of the maximum water available for crops (AWmax), could positively affect soil water balance, by reducing the irrigation needs (VIRR) and improving the irrigation water use efficiency (IWUE) and the water use efficiency (WUE). The analysis was performed for three crops, i.e., wheat (Triticum aestivum), sorghum (Sorghum vulgare) and tomato (Lycopersicon esculentum). BC was applied to the DS at different fractions, fBC (fBC = 0, 0.091, 0.23 and 0.33). Drip irrigation was adopted as a highly…
Sustainable technologies for greenhouse systems
2020
The greenhouse cultivation system in European countries represents one of the most energy-intensive sectors in the agriculture and agro-industry sector. In this regard, renewable energies represent an innovative solution to reduce energy costs and environmental impacts. Both, the energy demands and the economic aspects are analyzed with regard to the main energy users, i.e.: heating and cooling systems, lighting and pumping for irrigation. This work considers the use of solar photovoltaic and thermal energy. The use of semi-closed greenhouses is also considered.
Fruit quality and volatile fraction of ‘Pink Lady’ apple trees in response to rootstock vigor and partial rootzone drying
2008
BACKGROUND: Partial rootzone drying (PRD) is a novel deficit irrigation technique consisting in the alternated wetting of only one side of the rootzone, which induces partial stomatal closure and increased water use efficiency. The effect of PRD and rootstock vigor on ‘Pink Lady’ apple fruit quality and aroma profile was studied using solid-phase micro-extraction in headspace and gas chromatography/mass spectrometry. RESULTS: PRD irrigation generally did not affect quality attributes, whereas it influenced the aroma of the apple fruit. In particular, PRD improved the aroma of the fruit flesh, while it decreased the volatile fraction in the peel, where most of the compounds are concentrated.…
Assessment of yield and water productivity of clementine trees under surface and subsurface drip irrigation
2018
Abstract Irrigation systems aimed to optimize water use efficiency in agriculture have become essential due to the increasing water limitations that agriculture is currently facing. Assessment of crop responses to different irrigation systems and strategies are therefore encouraged to find the most efficient options for each specific case. The main objective of this study was to assess the performance of a citrus crop under a surface (SI) and subsurface drip irrigation (SSI) with 7 (SI7, SSI7) or 14 emitters (SI14, SSI14) per plant, as well as a third SS treatment (SSIA), identical to SSI7 but equipped with and additional drip line buried between the tree rows. Evaluations were made in term…
Effects of Saline and Deficit Irrigation on Soil-Plant Water Status and Potato Crop Yield under the Semiarid Climate of Tunisia
2019
Water supplies have been decreasing in several semi-arid regions, and it is therefore necessary to adopt irrigation strategies aimed at maximizing water use efficiency. In this paper, the effects of saline and deficit irrigation on water use efficiency and on potato crop response, based on observations of soil and plant water status, were investigated. Experiments were carried out in Central Tunisia, by monitoring potato crop growth during two seasons in four distinct treatments (T1&ndash
Is there a Market Value for Energy Performance in a Local Private Housing Market ? An efficiency analysis approach
2018
This paper aims to find evidence of a “green value” in a local housing market using notarial data on a small urban area in France. We use frontier functions, an original approach that departs from customary hedonistic regressions, to model housing market prices as a production set bordered by an efficiency frontier estimated by Data Envelopment Analysis (DEA). The paper tests if difference in prices (i.e. the distance from the frontier) can be explained by energy performance measured as a normalized categorical ascending kWh/m²/year grade (or Energy Performance Certificate -EPC). We show that there is significative evidence for energy performance's market value. The “Green Property Value” i…
Test of the European Joint Research Centre performance model for c-Si PV modules
2012
The performance of ten c-Si PV modules is studied at different levels of illumination and module temperatures and is modeled in terms of relative efficiency with respect to Standard Testing Conditions (STC). A recently proposed model is tested in Nordic conditions for generic mono- and mc-Si devices with screen-printed cells as well as for some high-efficiency cell designs. Two of the modules are field aged. Averaged model coefficients are derived and compared to values found in the literature. Irradiance and module temperatures measured in 2011 are then used to estimate the expected annual energy yields. The measured yields equal the predicted ones within 1.6% (mean bias error −1.0%) which…
Boosting the performance of a Reverse Electrodialysis – Multi-Effect Distillation Heat Engine by novel solutions and operating conditions
2019
Abstract This work presents a performance analysis of a waste-heat-to-power Reverse Electrodialysis Heat Engine (RED-HE) with a Multi-Effect Distillation (MED) unit as the regeneration stage. The performance of the system is comparatively evaluated using two different salts, sodium chloride and potassium acetate, and investigating the impact of different working solutions concentration and temperature in the RED unit. For both salt solutions, the impact of membrane properties on the system efficiency is analysed by considering reference ionic exchange membranes and high-performing membranes. Detailed mathematical models for the RED and MED units have been used to predict the thermal efficie…
Kilohertz and Low-Frequency Electrical Stimulation With the Same Pulse Duration Have Similar Efficiency for Inducing Isometric Knee Extension Torque …
2017
International audience; Objective To test the hypotheses that, as compared with pulsed current with the same pulse duration, kilohertz frequency alternating current would not differ in terms of evoked-torque production and perceived discomfort, and as a result, it would show the same current efficiency.Design A repeated-measures design with 4 stimuli presented in random order was used to test 25 women: (1) 500-microsecond pulse duration, (2) 250-microsecond pulse duration, (3) 500-microsecond pulse duration and low carrier frequency (1 kHz), (4) 250-microsecond pulse duration and high carrier frequency (4 kHz). Isometric peak torque of quadriceps muscle was measured using an isokinetic dyna…
Wage Structure and Labor Mobility in Norway 1980-1997
2007
To what extent do different firms follow different wage policies? How do such policies affect worker mobility between firms, and what are the effects of different wage bargaining regimes? The empirical branch of personnel economics has long been hampered by a lack of representative data sets. Norway is one of a handful of countries that has produced rich linked employer-employee data suitable for such analysis. This paper has three parts. First, we describe the wage setting and employment protection institutions in Norway. Next, we describe the Norwegian data sets. Finally, we document a large number of stylized facts regarding wage structure and labor mobility within and between Norwegian …