Search results for " Low"

Characterization of the ESR response of alanine dosimeters to low-energy (1-40 keV) X-rays

2016

The aminoacid L-a-alanine has attracted considerable interest for use in radiation ESR dosimetry and has been formally accepted as a secondary standard for high-dose (kGy) and transfer dosimetry . The accuracy of the method is quite high, largely due to the low dependence of the alanine response on various irradiation parameters (photon energies above 100 keV, dose rate, temperature, etc.). Furthermore, this system presents alinear response to dose, fairly high sensitivity, tissue equivalence, absence of fading, small dimensions, ruggedn ess, and non-destructive readout. In this work, we examined the energy dependence of alanine ESR dosimeters in the low energy X-photon energy range between…

Heteropolyacids - Chitosan Membranes for H2/O2 Low Temperature Fuel Cells

2016

Proton exchange membrane fuel cells (PEMFCs) have received much attention in recent years because of their high power density, efficiency and zero-environmental pollution. As one of the key components in fuel cells, the proton exchange membrane is expected to have high proton conductivity and good electrochemical stability. In the attempt to promote PEMCFs commercialization, high cost of fuel cell systems and short lifecycle are the two main issues that need to be addressed, thus large research effort has been devoted in developing new polymer electrolytes that can replace the usually employed proton conductors, e.g. Nafion®, with other membranes of comparable performances but lower cost.A…

Chitosan-heteropolyacid complex as high performance membranes for low temperature H2-O2 fuel cell

2014

Fabrication and Characterization of Chitosan-Heteropolyacid complex as membranes for low temperature H2-O2 fuel cell

2015

In this work we describe an easy procedure to fabricate homogeneous CS-HPA polyelectrolyte films using phosphotungstic acid (PTA) as cross-linking agent. The re action between CS chains and PTA is controlled in order to allow fabricating PEC thin films, that can be easily peeled off from the support, cut to any size and shape, whose thickness can be controlled by setting reticulation and time and/or chitosan concentration

Heteropolyacids - Chitosan Membranes for H2/O2 Low Temperature Fuel Cells

2016

Proton exchange membrane fuel cells (PEMFCs) have received much attention in recent years because of their high power density, efficiency and zero-environmental pollution. As one of the key components in fuel cells, the proton exchange membrane is expected to have high proton conductivity and good electrochemical stability. In the attempt to promote PEMCFs commercialization, high cost of fuel cell systems and short lifecycle are the two main issues that need to be addressed, thus large research effort has been devoted in developing new polymer electrolytes that can replace the usually employed proton conductors, e.g. Nafion®, with other membranes of comparable performances but lower cost. A…

Hybrid organic-inorganic membranes for low temperature H2-O2 fuel cell

2014

Pressure drop at low reynolds numbers in woven-spacer-filled channels for membrane processes: CFD prediction and experimental validation

2017

The energy consumption due to pumping power is a crucial issue in membrane processes. Spacers provide mechanical stability and promote mixing, yet increasing pressure drop. Woven spacers and their behaviour at low Reynolds numbers are less studied in the literature. Nevertheless, they are typical of some membrane technologies, as reverse electrodialysis (RED). RED is a promising technology for electric power generation by the chemical potential difference of two salt solutions within a stack equipped by selective ion-exchange membranes. The mechanical energy required for pumping the feed solutions, can dramatically reduce the net power output. In this work computational fluid dynamics (CFD)…

Potential applications of Salinity Gradient Power-Heat Engines for recovering low-temperature waste heat in cogeneration plants

2021

Abstract Salinity Gradient Power-Heat Engine is an innovative technology able to convert very low-temperature heat into electricity. Energy and economic benefits could be achieved by integrating this technology into cogeneration plants, where the exploitation of waste heat available during the operation could increase the revenues arising from “High-Efficiency” labels. For the first time, this paper proposes two potential applications in this field, and three illustrative case studies are purposely investigated. In the first case study, a salinity gradient-heat engine converts the waste heat available from a cogeneration plant serving an industrial process. In the second case study, a salin…

Electrochemical treatment of real wastewater with low conductivity

2018

In the last years, many efforts have been devoted to the development of electrochemical processes for the effective treatment of wastewater contaminated by organic pollutants resistant to conventional biological processes and/or toxic for microorganisms [1–5]. It was shown that some electrochemical approaches, including the direct anodic oxidation at suitable anodes such as boron-doped diamond (BDD) and/or electro-Fenton (EF) at suitable operating conditions and cells [1–6] could allow treating effectively a very large number of organic pollutants. However, most of the investigations were performed using synthetic wastewater. Hence, it is now mandatory to study the problems connected to the…

Design and experimental characterization of a low-cost, real-time, wireless AC monitoring system based on ATmega 328P-PU microcontroller

2015

This paper describes the development and experimental characterization of a real-time, low-cost, wireless AC monitoring system based on ATmega 328P-PU microcontroller. The proposed system is composed by a main brain for the acquisition and the processing of the data measured by smart meters. From the experimental tests discussed in this work it is demonstrated that the proposed system can monitor, with adequate accuracy, the working cycles of electrical loads in order to evaluate its energy consumption.