Search results for "efficiency."
showing 10 items of 1362 documents
Performance Prevision of a Turbocharged Natural Gas Fuelled S.I. Engine
2008
Natural gas represents today maybe the most valid alternative to conventional fuels for road vehicles propulsion. The main constituent of natural gas, methane, is characterized by a high autoignition temperature, which makes the fuel highly resistant to knocking: this allows a considerable downsizing of the engine by means of supercharging even under high compression ratio. Starting from these considerations, the authors realized a thermodynamic model of a 4-cilynder s.i. engine for the prevision of in-cylinder pressure, employing a two-zone approach for the combustion and adding sub-models to account for gas properties change and knocking occurrence. An extensive experimental campaign has …
PASSIVE SYSTEMS FOR BUILDINGS INDOOR COMFORT
2016
The paper shows the preliminary studies for the University Campus ZEB Energy realization in Palermo. The particular location in the Mediterranean basin has required careful planning to resolve the problems related to high temperatures and humidity. For this reason has been employed strategies, elements and building materials that meet the requirements of sustainability and energy savings provided by law, in order to build a new building energy self-sufficient. The University of Palermo had the need to create new spaces to be used as classrooms for different types of education and especially of a space for conferences and conventions. This type of spaces is usually very energy eater because …
Environmental Management Systems (Ems) - Control Instrument of the Impact of the Organization Activities on the Environment
2015
Abstract Due to the ability to create and use technology, the human being has found various ways to transform the resources of the Earth in all sorts of new materials, equipment and energy sources. At least since the last industrial revolution until now, each generation has added more technology to the received legacy, but at the same time, left the planet in a far more degraded state than the inherited condition. Within these changes, small and medium enterprises (SME) in their capacity as pillars of the economic development of a nation, have been compelled to change their previous strategies. Implementing an Environmental Management Systems (EMS) can be seen as the only way to connect the…
Changes in the total costs of the English and Welsh water and sewerage industry: The decomposed effect of price and quantity inputs on efficiency
2020
Abstract Understanding what drives changes in regulated water companies' costs is of great relevance to water regulators. This study decomposes and estimates the change in total costs for a sample of ten water and sewerage companies in England and Wales from 1993 to 2016. The results demonstrate that companies' total costs increased over time due to increases in input prices and input quantity. Any gains obtained from the efficient allocation of resources and technical progress were lost due to mergers and technical inefficiency. Finally, we link our results with the regulatory cycle to evaluate the impact of the regulatory regime on companies' costs and discuss some policy implications.
Examining Business Models of Software-as-a-Service Firms
2013
The paper focuses the attention to different business models and intended strategic aims of the firms providing Software-as-a-Service (SaaS). SaaS vendors have been said to challenge the business practices of the existing vendors providing proprietary or customer-specific solutions. The current studies on the topic have shown that SaaS is different from preceding software business models, but consider and emphasize SaaS business model as an invariable configuration. This case study compares two SaaS firms with different backgrounds and reveals characteristics of two very different SaaS business models. The findings indicate that along with SaaS vendors providing only standard software appli…
Conventional tillage versus no-tillage: Nitrogen use efficiency component analysis of contrasting durum wheat genotypes grown in a Mediterranean envi…
2023
Very little information is available for Mediterranean areas about the soil N dynamics and crop N use efficiency during the transition phase from conventional tillage (CT) to no-tillage (NT). Hence, a 2-yr experiment was conducted under semiarid Mediterranean conditions in three sites to study how soil N dynamics, crop N uptake, grain yield, and N use efficiency vary with N-fertilization rate and crop genotype in the switch year from CT to NT. Treatments consisted of two tillage systems (CT and NT), five N-fertilization rates (0, 40, 80, 120, and 160 kg N ha−1), and two durum wheat (Triticum durum Desf.) genotypes (one modern variety and one old landrace). Irrespective of the genotype, NT r…
Closure to “Laboratory and Field Calibration of the Diviner 2000 Probe in Two Types of Soil” by J. Haberland, R. Gálvez, C. Kremer, and C. Carter
2015
The authors deal with the quite interesting and actual problem of Diviner 2000 capacitance probe calibration and present some field and laboratory data obtained on two different layers (0–0.26 and 0.26–0.50 cm) of the same soil profile, characterized by different textural class. The importance of site-specific calibration of sensors used to monitor soil or plant water status assumes a particular relevance in semiarid environments where the application of precision irrigation represents an appropriate management strategy aimed to achieve high values of water use efficiency (Cammalleri et al. 2013). Moreover, in clay soils, physical properties are strongly influenced by soil water content (Pr…
Improving Perovskite Solar Cells: Insights From a Validated Device Model
2017
To improve the efficiency of existing perovskite solar cells (PSCs), a detailed understanding of the underlying device physics during their operation is essential. Here, a device model has been developed and validated that describes the operation of PSCs and quantitatively explains the role of contacts, the electron and hole transport layers, charge generation, drift and diffusion of charge carriers and recombination. The simulation to the experimental data of vacuum-deposited CH3NH3PbI3 solar cells over multiple thicknesses has been fit and the device behavior under different operating conditions has been studied to delineate the influence of the external bias, charge-carrier mobilities, e…
Sensitizer exchange dynamics in air and solvent filled semiconductor nanocavities
2010
Multiple dye binding sites and their exchange in equilibrium in air and solvent filled sensitized titanium oxide nanocavities were identified by 2DIR spectroscopy. Binding geometry and flexibility may influence electron injection efficiency of solar cells.
Routing Algorithm for Maximizing Lifetime of Wireless Sensor Network for Broadcast Transmission
2018
In the article we discuss solutions of the maximum lifetime broadcasting problem in wireless sensor networks. Due to limited energy resources of the network nodes to find an optimal transmission route of the broadcasted data we minimize the maximum energy consumed by the nodes. We give an analytical solution of the problem in one dimensional regular sensor network for the point-to-point and point-to-multipoint data transmission scheme. We show that in such a network, when the cost of data transmission is a polynomial function of distance between transmitter and receiver, there exist solutions with an equal energy, i.e., all nodes of the network consume the same amount of energy. We assume t…