Search results for "gas [meson]"

Eco-Efficiency of the English and Welsh Water Companies: A Cross Performance Assessment

2021

Analyzing costs and greenhouse gas (GHG) emissions could be of great importance for the water utilities to supply water services in a healthy and sustainable manner. In this study, we measured the eco-efficiency of several water utilities in England and Wales by incorporating GHG as an undesirable output. For the first time, we evaluated the eco-efficiency of the water production process using robust cross-efficiency data envelopment analysis (DEA) techniques. The further use of clustering and regression techniques allowed us to better understand the drivers of eco-efficiency. The results showed that the mean eco-efficiency of the water sector was 0.748, which indicates that costs and GHG e…

Essays On European Natural Gas Market

2018

La presente tesis ha cubierto diferentes aspectos de los mercados europeos del gas natural y la electricidad, en particular algunas propiedades que afectan a la efectividad de la cobertura, como la estacionalidad en varianza y en precios. Asimismo, se ha realizado un estudio de la prima de riesgo del gas natural, su relación con las variables de riesgo y su descomposición en una prima de riesgo de reinversión o ‘rollover’ y una prima de ‘preferencia por liquidez’ relacionada con el plazo. La tesis se compone de tres capítulos: el Capítulo I estudia la estacionalidad en los precios y la volatilidad y cómo mejora la efectividad de la cobertura teniendo en cuenta dicha estacionalidad; el Capít…

Preliminary results of systematic sampling of gas manifestations in geodynamically active areas of Greece

2016

Greece is located on a convergent plate boundary comprising the subduction of the African Plate beneath the Eurasian, while the Arabian plate approaches the Eurasian in a northwestward motion. It is considered to be one of the most tectonically active regions of Earth with a complex geodynamic setting, deriving from a long and complicated geological history. Due to this specific geological background, conditions for the formation of many thermal springs are favoured. In the past years, almost all the already known sites of degassing (fumaroles, soil gases, mofettes, gas bubbling in cold and thermal waters) located in the Hellenic area were sampled at least one time. Collected samples were a…

Sub-critical filtration conditions of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system: The effect of gas sparging i…

2012

A submerged anaerobic MBR demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON®, Koch Membrane Systems, PUR-PSH31) was operated using municipal wastewater at high levels of mixed liquor total solids (MLTS) (above 22gL -1). A modified flux-step method was applied to assess the critical flux (J C) at different gas sparging intensities. The results showed a linear dependency between J C and the specific gas demand per unit of membrane area (SGD m). J C ranged from 12 to 19LMH at SGD m values of between 0.17 and 0.5Nm 3h -1m -2, which are quite low in comparison to aerobic MBR. Long-term trials showed that the membranes operated steadily at fluxes close to the est…

Enzyme Affinity Assays Involving a Single-Use Electrochemical Sensor. Applications to the Enzyme Immunoassay of Human Chorionic Gonadotropin Hormone …

2000

Application of gas separation membranes to detritiation systems

2002

The use of gas separation membranes in tritium removal systems has been studied to develop a new detritiation process. The main advantage of this new process is to reduce the number and/or the size of equipments in comparison to conventional detritiation systems. The objective of this study is to choose the best suited membrane for this application. The hydrogen or its isotopes recovery performance of several commercial hollow fiber organic membranes has been analyzed thanks to three devices. Experiments are performed with small quantities of hydrogen gas or deuterium gas or tritium gas in the range representative of the radioactive contamination level in tritium handling gloveboxes. A math…

Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone

2017

Abstract Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO 2 flux of 15.3 ± 2.3 kg s − 1 (1325-ton day − 1 ) at Sabancaya and of 11.4 ± 3.9 kg s − 1 (988-ton day − 1 ) at Ubinas using scanning ultraviolet spectr…

Factors that affect the permeability of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system

2013

A demonstration plant with two commercial HF ultrafiltration membrane modules (PURON (R), Koch Membrane Systems, PUR-PSH31) was operated with urban wastewater. The effect of the main operating variables on membrane performance at sub-critical and supracritical filtration conditions was tested. The physical operating variables that affected membrane performance most were gas sparging intensity and back-flush (BF) frequency. Indeed, low gas sparging intensities (around 0.23 Nm(3) h(-1) m(-2)) and low BF frequencies (30s back-flush for every 10 basic filtration relaxation cycles) were enough to enable membranes to be operated sub-critically even when levels of mixed liquor total solids were hi…

Rīgas apkārtnes muižu attēlojums J.K. Broces “Zīmējumos un aprakstos”

2019

Maģistra darba ietvaros tiek veikts pētījums un veidots koptēls par Rīgas apkārtnes muižām, pamatojoties pedagoga, vēsturnieka, novadpētnieka J.K.Broces zīmētajiem, aprakstītajiem un apkopotajiem materiāliem no 1771. gada līdz 1818. gadam, kas tika publicēti krājumā 4 sējumos (1992-2007). Darbā tiek izmantoti pirmie 2 sējumi, kuros atspoguļota Rīga un tās tuvākā apkārtne. 18. gs. beigās un 19. gs. sākumā spilgta tendence bija muižu straujais pieaugums. Tās kalpoja īpašnieku prestižam, atpūtai, saimnieciskai darbībai un ekonomiskai izaugsmei. Rīgas apkārtnes muižiņu apbūve ir izzūdoša, tāpēc svarīgi, pēc iespējas vairāk un dažādos veidos pievērst uzmanību šim kultūras mantojumam. Muižiņu tēm…

Experimental design method to the weld bead geometry optimization for hybrid laser-MAG welding in a narrow chamfer configuration

2017

International audience; The work presented in this paper relates to the optimization of operating parameters of the welding by the experimental design approach. The welding process used is the hybrid laser-MAG welding, which consists in combining a laser beam with an MAG torch, to increase the productivity and reliability of the chamfer filling operation in several passes over the entire height of the chamfer. Each pass, providing 2 mm deposited metal and must provide sufficient lateral penetration of about 0.2 mm. The experimental design method has been used in order to estimate the operating parameters effects and their interactions on the lateral penetration on one hand, and to provide a…