Novel Centrifugal Compressor Architecture for Wide-Range Operation: A Feasibility Assessment

2017 ◽  
Author(s):  
Eric M. Krivitzky ◽  
Louis M. Larosiliere
Keyword(s):  
Internal Combustion Engines ◽  
Critical Role ◽  
Stability Boundary ◽  
Current Approach ◽  
Low Flow ◽  
Engine Operation ◽  
Feasibility Assessment ◽  
Wide Range ◽  
In Series ◽  
Low Efficiency

Turbocharger compressor performance plays a critical role in the ability of advanced Internal Combustion Engines (ICE) to meet the required fuel economy and drivability targets. Increased use of exhaust gas recirculation (EGR) combined with engine downsizing has pushed compressor operation towards — and often beyond — the stability boundary. However, certain applications and market trends require that no compromise be made to the rated power conditions. This has led to a highly disparate set of requirements for a single turbocharger system resulting in much of the compressor map, including the highest-efficiency area, unused or underutilized. A large percentage of the drive cycle is spent operating the compressor at low flow rates and low pressure ratios, near the compressor surge line, in an area of low efficiency. Compromises in efficiency in critical regions of engine operation result from balancing the disparate requirements. A current approach to meeting these disparate flow targets is the use of two turbochargers in series that are sized such that the operating compressor efficiency is markedly improved. This paper introduces a novel, hybrid single-stage compressor architecture which aerodynamically matches the functions of a series sequential dual turbocharger compression system. The use of a variable flow rate inducer bypass can provide a throttleable work-adding alternate flowpath for high-flow conditions, essentially emulating an efficient large compressor when the bypass is open and a small compressor when the bypass is closed. Using the variable bypass, the low-flow performance improves through an aerodynamically regulated inducer that is tailored to this flow regime. An engineering feasibility assessment supported by CFD, vector diagram analysis, and structural FEA suggest a substantial potential for improved performance across a wide flow range with this novel architecture.

The Piezoelectric Valve-Less Pump: Series and Parallel Connections

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Amos Ullmann ◽  
Yehuda Taitel
Keyword(s):  
Preferential Flow ◽  
Flow Direction ◽  
Open Circuit ◽  
Low Flow ◽  
Operational Conditions ◽  
Wide Range ◽  
Parallel Arrangement ◽  
In Series ◽  
Computational Fluid Dynamics Cfd ◽  
Parallel Connections

The piezoelectric valve-less pump is an attractive device to be used as a micropump for low flow rates. In these pumps, the nozzle/diffuser elements that have a preferential flow direction replace conventional valves, to direct the flow from the inlet to the outlet. This work is a study on the performance of such pumps when several of them (up to four) are combined for use in series and/or parallel arrangement. Two basic pumping configurations are considered: (a) pumping of fluid from low pressure to a higher pressure in an open circuit and (b) pumping of fluid in a closed circuit through a flow resistance. The performance analysis procedure developed is simple and quick and allows studying a wide range of operational conditions. Such an analysis is difficult to conduct using elaborate computational fluid dynamics (CFD) approach. The performance characteristics of the different combinations is reported and critically evaluated.

scholarly journals Effect of Flow Rate and Filter Efficiency on Indoor PM2.5 in Ventilation and Filtration Control

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1061 ◽  
Author(s):  
Ji-Hye Kim ◽  
Myoung-Souk Yeo
Keyword(s):  
Flow Rate ◽  
High Efficiency ◽  
Residential Buildings ◽  
Critical Role ◽  
Particle Model ◽  
Flow Rates ◽  
Filter Efficiency ◽  
Wide Range ◽  
Low Efficiency ◽  
Indoor Pm2.5

Ventilation and filtration control play a critical role in determining indoor PM2.5 (particles less than 2.5 μm in aerodynamic diameter) concentrations of outdoor or indoor origin in residential environments. The objective of this study was to investigate the combined effects of flow rates and filter efficiency on indoor PM2.5 concentrations of residential buildings in Seoul, Korea. Using a particle model based on a mass–balance equation, parametric analysis was performed to examine indoor PM2.5 concentrations according to flow rates and filter efficiency under a wide range of outdoor concentrations and indoor generations. Results showed that ventilation control equipped with a medium–efficiency filter was as effective as that with a high-efficiency filter under normal outdoor concentration and high indoor generation rate conditions. It is not recommended to apply a low-efficiency filter because indoor concentration increases rapidly as outdoor PM2.5 increases when ventilation flow rate is high. For filtration control, it is important to increase both flow rate and filter efficiency in order to improve indoor PM2.5 concentration.

scholarly journals Crank-Angle Resolved Flow Measurements in the Intake Duct of a Research Engine Using Novel and Fast Response Aerodynamic Probes

2021 ◽  
Vol 7 ◽  
Author(s):  
Fabian Großmann ◽  
Torsten Mühlpfordt ◽  
Patrick Rambacher ◽  
Georgios Bikas
Keyword(s):  
Gas Exchange ◽  
Time Resolution ◽  
Internal Combustion Engines ◽  
Current Approach ◽  
Operating Conditions ◽  
High Time Resolution ◽  
Flow Measurements ◽  
Engine Operation ◽  
Exhaust Duct ◽  
Crank Angle

Despite the public debate nowadays on the future of Internal Combustion Engines (ICE), which is impeding their development, one limitation towards further optimization of ICE in terms of fuel consumption and emissions can be seen in the current approach and more specifically in the transient engine operation and its control. The main drawbacks in the current approach source from: 1) complex structure of mechanization including sensors and actuators, 2) low time resolution and accuracy of sensing (cost driven), 3) complex Electronic Control Unit (ECU)-software architecture associated with huge calibration effort and 4) recently, funded research due to unsecure business model of ICE is becoming less. To overcome these difficulties unexploited potential should be utilized. Some of this potential lies in cycle-by-cycle and cylinder-by-cylinder accurate fuel and air control, and in the development of physical based virtual sensors with high time resolution and accuracy. One of the main motivations for this study was to develop a measurement technique that enables crank-angle resolved air mass flow rate measurements during engine operation in a dynamometer test cell. The measurement principle is quite simple and is based on gauging the dynamic pressure in both the intake and exhaust duct at the closest possible positions to the valves. To fulfill these requirements aerodynamic probes have been developed and manufactured utilizing 3D printing. The probes have been integrated in special developed flanges, which correspond exactly to the shape of the air channels in the cylinder head of the engine. Hence, they can be mounted either in front of the valves at the intake or behind the valves at the exhaust duct. Results at different engine operating conditions have been obtained, analyzed and correlated to other sensors like air-flow meter. Those post-processed results can be further used to validate 1-D gas exchange models, or 3-D Computational Fluid Dynamics (CFD) port flow models. The ultimate scope of these measurements is to calibrate fast physical-based gas exchange models that can be directly used in the engine control framework on an embedded system.

scholarly journals If spaces could talk what would they say - Spatial communication and Representation in Landscape Architecture

2021 ◽  
Author(s):  
◽  
Samantha Pead
Keyword(s):  
Community Engagement ◽  
Public Space ◽  
Landscape Architecture ◽  
Critical Role ◽  
Current Approach ◽  
Spatial Proximity ◽  
Public Project ◽  
Wide Range ◽  
Spatial Communication ◽  
Planning Processes

<p>An important component of landscape architecture is its ability to represent processes of re-imagining and designing the places we live in. The way we represent these processes of designing landscape presents an interesting opportunity for change in the current planning mechanisms of Aotearoa, New Zealand. Planning processes, such as engagement and consultation with the public, play a critical role in our ability to design the places we work and live successfully. These processes are often complex as they seek to address a wide range of technical, political, social and environmental issues. In all there complexity it is most often the task of engaging with community which is the first to be abandoned. Meaningful community engagement is critical to the success of any public project and needs to be better understood with regards to access and agency. If done well, community engagement has the ability to create good social outcomes and can lead to a greater sense of collective ownership. Landscape Architecture has the capability to bridge the gap between planning, public space, and communities by endeavouring to re-conceptualise the current approach toward community engagement processes. Current approaches to engagement in planning remain relatively formal and most often rely solely on written modes of public participation such as submissions. Spatial methods of communication are yet to be explored and tested in community engagement and provide an opportunity to reach marginalised communities, who are often missed in the current processes. This research identifies Kilbirnie as a suburb on the brink of significant spatial and social change. Based upon its spatial proximity to Wellington’s CBD, its growing and diversifying community, Kilbirnie presents a contentious site for future planning. The aim of this research is to expand traditional engagement mechanisms by using spatial mediums which provoke, and in turn, create meaningful community participation in the long term planning of Kilbirnie. This thesis will test the spatial as an effective medium for planning communication through a series of installations in Kilbirnie. The installations will be tested in sites that offer different typological qualities in order to understand how existing infrastructure can aid in the processes of spatial communication and engagement. This research argues that through installation and spatial communication it is possible to transform traditional forms of representation in planning and the attitudes of communities toward engaging with planning.</p>

scholarly journals If spaces could talk what would they say - Spatial communication and Representation in Landscape Architecture

2021 ◽  
Author(s):  
◽  
Samantha Pead
Keyword(s):  
Community Engagement ◽  
Public Space ◽  
Landscape Architecture ◽  
Critical Role ◽  
Current Approach ◽  
Spatial Proximity ◽  
Public Project ◽  
Wide Range ◽  
Spatial Communication ◽  
Planning Processes

<p>An important component of landscape architecture is its ability to represent processes of re-imagining and designing the places we live in. The way we represent these processes of designing landscape presents an interesting opportunity for change in the current planning mechanisms of Aotearoa, New Zealand. Planning processes, such as engagement and consultation with the public, play a critical role in our ability to design the places we work and live successfully. These processes are often complex as they seek to address a wide range of technical, political, social and environmental issues. In all there complexity it is most often the task of engaging with community which is the first to be abandoned. Meaningful community engagement is critical to the success of any public project and needs to be better understood with regards to access and agency. If done well, community engagement has the ability to create good social outcomes and can lead to a greater sense of collective ownership. Landscape Architecture has the capability to bridge the gap between planning, public space, and communities by endeavouring to re-conceptualise the current approach toward community engagement processes. Current approaches to engagement in planning remain relatively formal and most often rely solely on written modes of public participation such as submissions. Spatial methods of communication are yet to be explored and tested in community engagement and provide an opportunity to reach marginalised communities, who are often missed in the current processes. This research identifies Kilbirnie as a suburb on the brink of significant spatial and social change. Based upon its spatial proximity to Wellington’s CBD, its growing and diversifying community, Kilbirnie presents a contentious site for future planning. The aim of this research is to expand traditional engagement mechanisms by using spatial mediums which provoke, and in turn, create meaningful community participation in the long term planning of Kilbirnie. This thesis will test the spatial as an effective medium for planning communication through a series of installations in Kilbirnie. The installations will be tested in sites that offer different typological qualities in order to understand how existing infrastructure can aid in the processes of spatial communication and engagement. This research argues that through installation and spatial communication it is possible to transform traditional forms of representation in planning and the attitudes of communities toward engaging with planning.</p>

DIESEL ENGINE OPERATION IN USE OF FUEL WITH ADDITIVES

2018 ◽  
pp. 18-24
Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Combustion Engines ◽  
Engine Operation ◽  
Factors Affecting ◽  
Operating Modes ◽  
Positive Effects

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.

Shooting a Tiger

2018 ◽  
Author(s):  
Vijaya Ramadas Mandala
Keyword(s):  
Critical Role ◽  
Late Nineteenth Century ◽  
Way Of Life ◽  
Colonial India ◽  
British Raj ◽  
Early Colonial ◽  
Wide Range ◽  
Forest Legislation ◽  
Imperial Governance ◽  
North And South

The main contention of Shooting a Tiger is that hunting during the colonial period was not merely a recreational activity, but a practice intimately connected with imperial governance. The book positions shikar or hunting at the heart of colonial rule by demonstrating that, for the British in India, it served as a political, practical, and symbolic apparatus in the consolidation of power and rule during the nineteenth and early twentieth centuries. The book analyses early colonial hunting during the Company period, and then surveys different aspects of hunting during the high imperial decades in the later nineteenth and early twentieth centuries. The book draws upon an impressive array of archival material and uses a wide range of evidence to support its contentions. It examines hunting at a variety of social and ethnic levels—military, administrative, elite, princely India, Indian professional hunters, and in terms of Indian auxiliaries and (sometimes) resisters. It also deals with different geographical contexts—the plains, the mountains, north and south India. The exclusive privilege of hunting exercised by the ruling classes, following colonial forest legislation, continued to be extended to the Indian princes who played a critical role in sustaining the lavish hunts that became the hallmark of the late nineteenth-century British Raj. Hunting was also a way of life in colonial India, undertaken by officials and soldiers alike alongside their everyday duties, necessary for their mental sustenance and vital for the smooth operation of the colonial administration. There are also two final chapters on conservation, particularly the last chapter focusing on two British hunter-turned-conservationists, Jim Corbett and Colonel Richard Burton.

Measurement of cycle-resolved engine-out soot concentration from a diesel-pilot assisted natural gas direct-injection compression-ignition engine

2021 ◽  
pp. 146808742098626
Author(s):  
Pooyan Kheirkhah ◽  
Patrick Kirchen ◽  
Steven Rogak
Keyword(s):  
Response Time ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Exhaust System ◽  
Cycle Period ◽  
Scanning Mobility Particle Sizer ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Exhaust Port ◽  
Exhaust Stream

Exhaust-stream particulate matter (PM) emission from combustion sources such as internal combustion engines are typically characterized with modest temporal resolutions; however, in-cylinder investigations have demonstrated significant variability and the importance of individual cycles in transient PM emissions. Here, using a Fast Exhaust Nephelometer (FEN), a methodology is developed for measuring the cycle-specific PM concentration at the exhaust port of a single-cylinder research engine. The measured FEN light-scattering is converted to cycle-resolved soot mass concentration ([Formula: see text]), and used to characterize the variability of engine-out soot emission. To validate this method, exhaust-port FEN measurements are compared with diluted gravimetric PM mass and scanning mobility particle sizer (SMPS) measurements, resulting in close agreements with an overall root-mean-square deviation of better than 30%. It is noted that when PM is sampled downstream in the exhaust system, the particles are larger by 50–70 nm due to coagulation. The response time of the FEN was characterized using a “skip-firing” scheme, by enabling and disabling the fuel injection during otherwise steady-state operation. The average response time due to sample transfer and mixing times is 55 ms, well below the engine cycle period (100 ms) for the considered engine speeds, thus suitable for single-cycle measurements carried out in this work. Utilizing the fast-response capability of the FEN, it is observed that cycle-specific gross indicated mean effective pressure (GIMEP) and [Formula: see text] are negatively correlated ([Formula: see text]: 0.2–0.7), implying that cycles with lower GIMEP emit more soot. The physical causes of this association deserve further investigation, but are expected to be caused by local fuel-air mixing effects. The averaged exhaust-port [Formula: see text] is similar to the diluted gravimetric measurements, but the cycle-to-cycle variations can only be detected with the FEN. The methodology developed here will be used in future investigations to characterize PM emissions during transient engine operation, and to enable exhaust-stream PM measurements for optical engine experiments.

scholarly journals Proteomic Analysis of Zeb1 Interactome in Breast Carcinoma Cells

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3143
Author(s):  
Sergey E. Parfenyev ◽  
Sergey V. Shabelnikov ◽  
Danila Y. Pozdnyakov ◽  
Olga O. Gnedina ◽  
Leonid S. Adonin ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Epithelial To Mesenchymal Transition ◽  
Critical Role ◽  
Malignant Neoplasm ◽  
Malignant Neoplasms ◽  
Breast Cancer Patients ◽  
Survival Prognosis ◽  
Mesenchymal Transition ◽  
Wide Range

Breast cancer is the most frequently diagnosed malignant neoplasm and the second leading cause of cancer death among women. Epithelial-to-mesenchymal Transition (EMT) plays a critical role in the organism development, providing cell migration and tissue formation. However, its erroneous activation in malignancies can serve as the basis for the dissemination of cancer cells and metastasis. The Zeb1 transcription factor, which regulates the EMT activation, has been shown to play an essential role in malignant transformation. This factor is involved in many signaling pathways that influence a wide range of cellular functions via interacting with many proteins that affect its transcriptional functions. Importantly, the interactome of Zeb1 depends on the cellular context. Here, using the inducible expression of Zeb1 in epithelial breast cancer cells, we identified a substantial list of novel potential Zeb1 interaction partners, including proteins involved in the formation of malignant neoplasms, such as ATP-dependent RNA helicase DDX17and a component of the NURD repressor complex, CTBP2. We confirmed the presence of the selected interactors by immunoblotting with specific antibodies. Further, we demonstrated that co-expression of Zeb1 and CTBP2 in breast cancer patients correlated with the poor survival prognosis, thus signifying the functionality of the Zeb1–CTBP2 interaction.

Synthesis and characterization of a new series of thiadiazole derivatives as potential anticancer agents

2020 ◽  
Vol 26 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Ulviye Acar Çevik ◽  
Derya Osmaniye ◽  
Serkan Levent ◽  
Begüm Nurpelin Sağlik ◽  
Betül Kaya Çavuşoğlu ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Biological Activities ◽  
Cancer Cell Line ◽  
Chemotherapeutic Agents ◽  
Anticancer Activities ◽  
Normal Tissues ◽  
H Nmr ◽  
Wide Range ◽  
Thiadiazole Derivatives ◽  
Low Efficiency

AbstractCancer is one of the most common causes of death in the world. Despite the importance of combating cancer in healthcare systems and research centers, toxicity in normal tissues and the low efficiency of anticancer drugs are major problems in chemotherapy. Nowadays the aim of many medical research projects is to discover new safer and more effective anticancer agents. 1,3,4-Thiadiazole compounds are important fragments in medicinal chemistry because of their wide range of biological activities, including anticancer activities. The aim of this study was to determine the capacity of newly synthesized 1,3,4-thiadiazole compounds as chemotherapeutic agents. The structures of the obtained compounds were elucidated using 1H-NMR, 13C-NMR and mass spectrometry. Although the thiadiazole derivatives did not prove to be significantly cytotoxic to the tumour tissue cultures, compound 4i showed activity against the C6 rat brain cancer cell line (IC50 0.097 mM) at the tested concentrations.

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