Search results for "efficiency."

Energy conversion efficiency in betavoltaic cells based on the diamond Schottky diode with a thin drift layer

2020

The HPHT diamond Schottky diode was assembled as a Metal/Intrinsic/p-doped structure betavoltaic cell (BC) with a very thin (1 μm) drift layer and tested under 5–30 keV electron beam irradiation using a scanning electron microscope (SEM). The effect of the β-radiation energy and the backscattering of electrons on the energy conversion was studied. From the results obtained, it is shown that, the efficiency of the investigated BC increases from 1.01 to 3.75% with the decrease of β-particle energy from 30 to 5 keV due to an increase of the electron beam absorption in a thin drift layer. Maximum efficiency is achieved when the electron beam energy is close to the average β-decay energy of 3H. …

Wireless Charging Systems for Electric Vehicle Batteries

Interspecific extrinsic and intrinsic competitive interactions in egg parasitoids

2012

Interspecific competitive interactions can occur either between adult parasitoids searching/exploiting hosts (extrinsic competition) or between parasitoid larvae developing within the same host (intrinsic competition). Understanding how interspecific competition between parasitoids can affect pest suppression is important for improving biological pest control. The purpose of this work was to review both extrinsic and intrinsic competition between egg parasitoid species. These are organisms that are often candidates for biological control programs due to their ability to kill the pest before the crop feeding stage. We first reviewed the literature about interspecific competitive abilities of…

Measurement of Photosynthesis and Transpiration in Spruce Trees with Various Degrees of Damage

1987

Summary In the context of a project on physiological and biochemical characterization of spruce with different degrees of damage, the C02 and H2O gas exchange of 22-year-old spruce from a location in the Hunsru.ck (West Germany) were measured in summer 1985. The measurements were carried out on shoots from 1984 and were set up as a pair comparison, i.e. the measurement data of a tree with symptoms of damage were always compared with a tree in the immediate vicinity which phenotypically showed less damage. Diurnal course measurements in the open air revealed a marked reduction of photosynthesis depending on the degree of damage of the trees. If one plots photosynthetic rate against light int…

Eco-efficiency assessment of olive farms in Andalusia

2012

Abstract Olive farming represents an important source of income and employment in the rural areas of Andalusia (Spain), which is the most important olive oil-producing region in the world. Unfortunately, it also exerts significant environmental pressures with regard to soil erosion, use of polluting inputs, excessive water consumption and biodiversity reduction. This paper uses Data Envelopment Analysis (DEA) techniques and pressure distance functions to contribute a farm-level assessment of the eco-efficiency of a sample of 292 Andalusian olive farmers. We distinguish between managerial eco-efficiency and program eco-efficiency, the latter being associated to the different natural conditio…

Current characterisation for ultra low power wireless body area networks

2010

The emerging area of body area networks (BAN) imposes challenging requirements on hardware and software to achieve the desired lifetimes for certain devices such as long term medical implants. In this paper, we propose a novel approach to the measurement and characterisation of the energy consumption of BAN devices. The approach uses a low cost energy auditing circuit and addresses the problem of accurately measuring low-level current consumption. This new technique will allow precise and analytical measurements of systems and components in terms of energy. This will help circuit designers minimise power consumption in BAN devices. Software engineers might use this approach to validate and …

Evaluation of Load transfer in rigid pavements by Rolling wheel deflectometer and Falling weight deflectometer

2020

Abstract Rigid pavements have widespread use, e.g, in motorways and airports, due to their excellent properties such as high bearing capacity and long lifetime. However, when rigid pavements fail it is often due to bad load transfer efficiency (LTE) at its joints. Traditional methods of measuring LTE can be time consuming. Here, we study the possibility of measuring LTE using a moving load with the aim of achieving higher productivity. An experiment simulating Rolling Weight Deflectometer (RWD) measurements on a joint was carried out to gain understanding and confidence that can guide the analysis of real RWD data. Continuous data from measurements across a joint allows for determination of…

1 Hop or 2 hops: Topology analysis in Body Area Network

2014

Wireless Body Area Networks (WBANs) have recently received much attention due to the possibility to be used in healthcare applications. For these applications, link reliability and energy efficiency are critical issues, as in many cases, information carried can be vital for the patient and batteries cannot be easily replaced. The wireless on-body channel experiences significant temporal variation due to body movements and the use of relays is sometimes necessary in order to guarantee reliability or improve lifetime. In this paper, an experimental evaluation is used to give a better understanding about reliability, energy consumption and lifetime in a single hop or a two hops communication. …

Artificial dielectric optical structures: A challenge for nanofabrication

1998

Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.

The use of energy in the Mediterranean fishing catching sector. A Sicilian perspective

2010

This article address an issue of paramount importance in the Mediterranean area, that is the efficient use of energy and sustainability of fishing sector. A recent study concerning the situation of Fishery and Aquaculture in Sicily highlighted that the Sicilian fishing system requires a bigger amount of energy than the typical Italian or European situation, in order of getting the product available to the market. On the other hand this involves an higher level of environmental pollution, for a given quantity of catch. One of the main findings is that there is a need for a clear, scientifically-founded panorama of the situation and that further studies should be undertaken to provide fishing…