A study of pressure fluctuations caused by vortex breakdown.

Imperial Users onl

Composition measurements of crude oil and process water emulsions using thick-film ultrasonic transducers

This paper presents an experimental study to investigate the suitability of thick-film ultrasonic transducers for composition measurements in heterogeneous mixtures. Following on from earlier developments [G. Meng, A.J. Jaworski, T. Dyakowski, J.M. Hale, N.M. White, Design and testing of a thick-film dual-modality sensor for composition measurements in heterogeneous mixtures, Meas. Sci. Technol. 16(4) (2005) 942–954], focused on the design and preliminary testing of the transducers for mixtures of vegetable oil and salty water, the current paper looks in more detail into their application to industrially relevant fluids, namely crude oil and process water, which are common in oil and gas extraction and petrochemical industries. The measurements are based on the time-of-flight of the ultrasonic pressure wave in order to obtain the speed of sound. The results, showing the variation of the speed of sound with the volume fraction of crude oil, for three different temperatures, are compared with five theoretical models available in the existing literature. It is shown that the models proposed by Urick [R.J. Urick, A sound velocity method for determining the compressibility of finely divided substances, J. Appl. Phys. 18 (1947) 983–987] and by Kuster and Toks¨oz [G.T. Kuster, M.N. Toks¨oz, Velocity and attenuation of seismic waves in two-phase media. Part I. Theoretical formulations, Geophysics 39 (1974) 587–606] provide a relatively accurate prediction for the speed of sound in the media studied. Interestingly, the model developed by Povey and co-workers [V.J. Pinfield, M.J.W. Povey, Thermal scattering must be accounted for in the determination of adiabatic compressibility, J. Phys. Chem. B 101 (1997) 1110–1112] only agrees with experiment when its thermal scattering features are neglected. Overall, the results obtained demonstrate that the slim-line and compact thick-film transducers can be considered as a viable means for the composition measurements in the process conditions

Bubble size and bubble rise velocity estimation by means of electrical capacitance tomography within gas-solids fluidized beds

Electrical capacitance tomography (ECT) has been developed as a non-invasive and non-intrusive measurement technique to investigate the internal hydrodynamic characteristics of gas-solids systems in fluidized beds. This paper describes an investigation, in which a customized twin-plane ECT sensor was designed and constructed to study the fluid flow processes within a bench-scale gas-solids fluidized bed. A detailed calibration process was conducted using hollow plastic balls of different diameters to derive the reference grey level cut-off values for determining the bubble diameter. In addition, numerical simulations were carried out to investigate the plastic ball wall effect on measured capacitance values. Bubble diameters were estimated by means of the individual reference cut-off values and their linear and second-order fitted curves. Linear back-projection (LBP) and iterative LBP image reconstruction algorithms were compared with respect to estimating the bubble diameter. A number of approaches were investigated to estimate the bubble rise velocity including three methods based on cross-correlation techniques and the detailed signal analysis. Bubble diameters were also obtained using a new approach based on “back-calculation” of the bubble rise velocity through widely accepted empirical correlations from the existing literature

A city and river in pre-industrial East-Central Europe. Case study: Wrocław

The aim of the article is to assess the relationship between living conditions in the city and the natural environment determined by a large lowland river. This problem was examined via the example of Wrocław, the main city in Lower Silesia, which developed on the border of cultural and political zones. The natural hydrographic network and the scope of anthropogenic changes are presented. Also analysed are aspects of the land’s suitability for construction, water supply techniques for crafts and townspeople’s houses, drainage techniques, protection of street and squares surfaces against mud, and the use of water for defensive purposes. The chronological framework extends from the beginning of settlement to industrialisation and the introduction of modern water and sewage techniques in the 19th century.The aim of the article is to assess the relationship between living conditions in the city and the natural environment determined by a large lowland river. This problem was examined via the example of Wrocław, the main city in Lower Silesia, which developed on the border of cultural and political zones. The natural hydrographic network and the scope of anthropogenic changes are presented. Also analysed are aspects of the land’s suitability for construction, water supply techniques for crafts and townspeople’s houses, drainage techniques, protection of street and squares surfaces against mud, and the use of water for defensive purposes. The chronological framework extends from the beginning of settlement to industrialisation and the introduction of modern water and sewage techniques in the 19th century

Assessing Vehicle Emissions from a Multi-Lane to Turbo Roundabout Conversion Using a Microsimulation Tool

The development of urban strategies for the reduction of environmental impacts and decarbonization requires ongoing monitoring from the local scale and further deployment of actions to improve transport demand (user characteristics and modal choice) and supply (infrastructure and services). The analysis of pollution sources and the evaluation of possible scenarios are preliminary to the mitigation of impacts. In particular, the study of geometrical and functional characteristics of infrastructures through micro-simulation allows understanding of which schemes can support the reduction of emissions and guarantee high levels of service (LOS), reducing the problem of vehicular congestion in urban areas. The present work focuses on the small-scale analysis of vehicular traffic emissions at a multi-lane roundabout road intersection and the comparison of geometric schemes (current and design) and use with a turbo roundabout scheme as traffic volumes changes. These volumes have plummeted due to the current COVID-19 pandemic. The results show that the geometric-functional modification of the roundabout intersection from a multi-lane to a turbo-roundabout intersection allows a reduction of up to 30% of the emissions considering the current composition of the traffic fleet in the city of Rzeszow in Poland. The proposed comparative analysis methodology can contribute to the drafting of sustainable urban mobility plans (SUMPs) proposing a set of investments for new road works and considering a number of scenarios with interventions that can be implemented in the medium and long term that can provide the incentive to reduce road congestion and vehicular emissions

Ostre poprzetoczeniowe uszkodzenie płuc u młodej kobiety z ciążą ektopową – opis przypadku i przegląd literatury

Background: Transfusion-related acute lung injury (TRALI) is a major cause of death associated with transfusion. Nevertheless it is still misdiagnosed and underreported. We present a case of this serious complication in order to make it more familiar to clinicians and indicate proper medical management, which is significant not only for the patients presenting TRALI symptoms but also for future recipients of blood components. Case presentation: A 32-year-old white woman with in-vitro fertilization in anamnesis was admitted to Department of Obstetrics and Gynecology because of abdominal pain. Ultrasonography examination revealed pathological mass in left adnexa. The patient underwent laparoscopic left salpingectomy. The following day she reported progressive pain in lower abdomen with signs of peritoneal irritation. Emergency laparotomy was performed and active bleeding from fallopian tube was stopped. Four units of red blood cells concentrate and six units of fresh frozen plasma were transfused. Within two hours of surgery acute respiratory distress symptoms occurred, bilateral infiltrates were found on chest X-ray. The patient responded to supportive treatment (oxygen therapy, dexamethasone, diuretics) and her state improved within 12 hours. Serological diagnostics revealed anti-HLA antibodies in one donor which reacted with patient’s granulocytes. Clinical picture and anti-leukocyte antibodies detected in blood component allowed to identify the immune-mediated TRALI. Conclusions: Transfusion-related acute lung injury is a life-threatening complication of transfusion which manifests as non-cardiogenic pulmonary edema. Each suspected case of this syndrome should be reported to blood center in order to confirm the diagnosis and implement preventive measures (exclusion of implicated donor from further blood donation).  Cel pracy: Ostre poprzetoczeniowe uszkodzenie płuc (TRALI) jest jedną z głównych przyczyn zgonów związanych z transfuzją składników krwi. Niemniej jednak powikłanie to pozostaje często nierozpoznawane lub niezgłaszane do odpowiednich ośrodków. W niniejszej pracy prezentujemy przypadek tego poważnego powikłania w celu przybliżenia jego obrazu klinicznego i wskazania prawidłowego postępowania, które jest nie tylko istotne dla pacjenta z objawami TRALI, ale także dla przyszłych biorców preparatów krwiopochodnych. Opis przypadku: 32-letnia kobieta rasy kaukaskiej z wywiadem zapłodnienia pozaustrojowego została przyjęta do Kliniki Położnictwa i Ginekologii z powodu bólu brzucha. Badanie ultrasonograficzne ujawniło obecność patologicznej masy w obrębie lewych przydatków macicy. Pacjentka przebyła lewostronną laparoskopową salpingektomię. Następnego dnia zgłosiła narastające dolegliwości bólowe w podbrzuszu z cechami podrażnienia otrzewnej. Przeprowadzono pilną laparotomię, w trakcie której zatamowano aktywne krwawienie z kikuta jajowodu. Pacjentce przetoczono 6 jednostek koncentratu krwinek czerwonych i 4 jednostki świeżo mrożonego osocza. Po 2 godzinach od operacji wystąpiły objawy ostrej niewydolności oddechowej a w rentgenogramie klatki piersiowej stwierdzono obustronne zacienienia. Zastosowano leczenie podtrzymujące: tlenoterapia bierna, deksametazon, diuretyki. Stan pacjentki uległ poprawie w ciągu 12 godzin. Diagnostyka serologiczna ujawniła u jednego dawcy krwi obecność przeciwciał anti-HLA reagujących z granulocytami pacjentki. Obraz kliniczny i przeciwciała antyleukocytarne wykryte w przetoczonym składniku krwi pozwoliły rozpoznać immunologiczną postać TRALI. Wnioski: Ostre poprzetoczeniowe uszkodzenie płuc jest zagrażającym życiu powikłaniem potransfuzyjnym, które manifestuje się jako niekardiogenny obrzęk płuc. Wszystkie przypadki z objawami wskazującymi na wystąpienie tego zespołu powinny być zgłaszane do Centrów Krwiodawstwa i Krwiolecznictwa celem potwierdzenia diagnozy i wdrożenia odpowiednich środków profilaktycznych (wyłączenie dawcy z przeciwciałami antyleukocytarnymi z dalszego oddawania krwi dla celów klinicznych).

Evaluation of the potential of commercial use of microalgae in the world and in Ukraine

This paper aims to evaluate of the microalgae potential for commercial application, in particular to conduct experimental study of biogenic compounds removal from sewage waters by microalgae, and to calculate economical benefits from biofertizers and biofuel production. Experimental study in the concentration change of nitrogen and phosphorus compounds in the cultivation of Chlorella Vulgaris microalgae in various types of sewage water was carried out. The efficiency wastewater treatment by microalgae was confirmed. The economic benefit from the biomass utilization as biofuel production was calculated. Implementation of wastewater treatment technology with biomass recycling for biofuel and biofertilizers production will minimize the impact. As a results of experimental studies, the ability of microalgae to reduce biogenic elements in wastewater was confirmed. Microalgae can be used both for wastewater treatment to biogenic elements removal, such as phosphorous and nitrogen compounds, and biofuel, biofertilizers production. Prospects of the commercial use of microalgae are obvious. They are specially adapted to an environment dominated by viscous forces

Design and construction of a two-stage thermoacoustic electricity generator with push-pull linear alternator

Travelling-wave thermoacoustic heat engine is capable of converting heat to acoustic power which in turn can be used to generate electricity by a linear alternator. The thermoacoustic heat engine can work in a wide range of heat quality, giving it the ability to be used for waste heat recovery. In this paper, a new configuration of looped-tube travelling wave thermoacoustic engine is proposed, which consists of two identical stages each having a power extraction point, and the linear alternator connecting these two points working in “push-pull” mode. This enables a more effective acoustic impedance matching compared to the use of multiple linear alternators known in the literature. The laboratory demonstrator has been designed, built and tested. The applied heat source temperature is similar to that of the internal combustion engine exhaust gases in order to explore the potential of using the device for waste heat recovery from road or marine transport. In experiments, the maximum electric power of 48.6 W at thermal-to-electric efficiency of around 6% was achieved with helium at 28 bar as working fluid and 297 K temperature difference across the regenerator. The performance of the device has been analysed and compared to modelling performed using DeltaEC simulation tool