scholarly journals Gas fired boilers: Perspective for near future fuel composition and impact on burner design process

2017 ◽  
Vol 22 ◽  
pp. 00154 ◽  
Author(s):  
Fabio Schiro ◽  
Anna Stoppato ◽  
Alberto Benato
Keyword(s):  
Design Process ◽  
Fuel Composition ◽  
Burner Design ◽  
Near Future

Outdoor Seating Design to Facilitate Social Interaction Among Older Adults

2009 ◽  
Vol 17 (4) ◽  
pp. 4-27 ◽  
Author(s):  
Thamar Swart ◽  
Johan Molenbroek ◽  
Lau Langeveld ◽  
Martin Van Brederode ◽  
Brecht J. Daams
Keyword(s):  
Older Adults ◽  
Social Interaction ◽  
The Netherlands ◽  
Design Process ◽  
Literature Search ◽  
Public Spaces ◽  
Usability Test ◽  
Public Meeting ◽  
Near Future

AT A GLANCE: The number of older adults who like to meet each other in public spaces in the Netherlands is increasing. For this article, older adults were surveyed regarding their wants and needs for public meeting spaces. By means of a literature search on ergonomics, interviews, observations, and discussions with experts and older adults, a list of needs and preferences was created and used to guide a design for an outdoor meeting space for older adults, dubbed “The Oud-door.” Older adults were engaged in the design process by asking them questions, discussing the ideas and concepts with them, and, finally, conducting a usability test. Manufacturer Jan Kuipers Nunspeet will develop this design further, and “The Oud-door” will be available on the market in the near future.

Effect of Change in Fuel Compositions and Heating Value on Ignition and Performance for Siemens SGT-400 Dry Low Emission Combustion System

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Kexin Liu ◽  
Pete Martin ◽  
Victoria Sanderson ◽  
Phill Hubbard
Keyword(s):  
Natural Gas ◽  
Fuel Composition ◽  
Test Results ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Fuel Flexibility ◽  
Low Emission ◽  
Burner Design ◽  
Industrial Gas Turbine

The influence of changes in fuel composition and heating value on the performance of an industrial gas turbine combustor was investigated. The combustor tested was a single cannular combustor for Siemens SGT-400 13.4 MW dry low emission engine. Ignition, engine starting, emissions, combustion dynamics, and flash back through burner metal temperature monitoring were among the parameters investigated to evaluate the impact of fuel flexibility on combustor performance. Lean ignition and extinction limits were measured for three fuels with different heat values in term of Wobbe Index (WI): 25, 28.9, and 45 MJ/Sm3 (natural gas). The test results show that the air fuel ratio at lean ignition/extinction limits decreases and the margin between the two limits tends to be smaller as fuel heat value decreases. Engine start tests were also performed with a lower heating value fuel and results were found to be comparable to those for engine starting with natural gas. The combustor was further tested in a high pressure air facility at real engine operating conditions with different fuels covering WIs from 17.5 to 70 MJ/Sm3. The variation in fuel composition and heating value was achieved in a gas mixing plant by blending natural gas with CO2, CO, N2, and H2 (for the fuel with WI lower than natural gas) and C3H8 (for the fuel with WI higher than natural gas). Test results show that a benefit in NOx reduction can be seen for the lower WI fuels without H2 presence in the fuel and there are no adverse impacts on combustor performance except for the requirement of higher fuel supply pressure, however, this can be easily resolved by minor modification through the fuel injection design. Test results for the H2 enriched and higher WI fuels show that NOx, combustion dynamics and flash back have been adversely affected and major change in burner design is required. For the H2 enriched fuel, the effect of CO and H2 on combustor performance was also investigated for the fuels having a fixed WI of 29 MJ/Sm3. It is found that H2 dominates the adverse impact on combustor performance. The chemical kinetic study shows that H2 has significant effect on flame speed change and CO has significant effect on flame temperature change. Although the tests were performed on the Siemens SGT-400 combustion system, the results provide general guidance for the challenge of industrial gas turbine burner design for fuel flexibility.

scholarly journals From the Martian Surface to Its Low Orbit in a Reusable Single-Stage Vehicle—Charon

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 153
Author(s):  
Jérémie Gaffarel ◽  
Afrasiab Kadhum ◽  
Mohammad Fazaeli ◽  
Dimitrios Apostolidis ◽  
Menno Berger ◽  
...  
Keyword(s):  
Design Process ◽  
Fault Tree Analysis ◽  
Maximum Growth ◽  
Single Stage ◽  
Preliminary Design ◽  
Martian Surface ◽  
Tree Analysis ◽  
Iterative Design ◽  
Near Future ◽  
Mission Profile

With Mars colonisation becoming a reality for the near future, it is of importance to analyse how crew and cargo can be transported between Earth and a colony on Mars. This article is a feasibility and design study of a launch vehicle whose mission is to shuttle crew and cargo from Low Mars Orbit to a colony on the Martian surface. A single-stage reusable rocket has been selected to fulfil this mission, code-named Charon. The mission profile of such a vehicle was created, leading to a Maximum Growth Allowance (MGA) Delta-V budget of 6.2 km/s. With the mission profile in mind, each subsystem underwent a preliminary design. With reliability and maintainability in mind, subsystems were designed for redundancy and modularity, and an abort system was included for an added level of safety. The iterative design process resulted in a vehicle with a MGA mass of 198.7 tons, capable of transporting 1200 kg of cargo and a crew of 6 people to a 500 km orbit and back. The preliminary design of the vehicle is deemed safe. Following a fault tree analysis, the Single Launch Loss of Mission, Vehicle and Crew (SL-LOM, SL-LOV, SL-LOC) probabilities are computed to be of 0.975%, 0.12%, and 0.079%. Finally, from the vehicle’s constraints on the base, the feasibility of the project has been reflected upon. It is deemed that such a concept is of high interest only when the base is already operational, due to the launch and maintenance infrastructure that it requires, as well as the power it requires from the Martian base.

Design and Validation of a Reduced Test Matrix for the Autoignition of Gas Turbine Fuel Blends

2005 ◽  
Author(s):  
Jaap de Vries ◽  
Eric L. Petersen
Keyword(s):  
Design Methodology ◽  
Fuel Composition ◽  
Fuel Blend ◽  
Reasonable Time ◽  
Test Matrix ◽  
Fuel Blends ◽  
Wide Range ◽  
Aero Engine ◽  
Burner Design ◽  
And Performance

Changes in fuel composition for both aero-engine as well as power generation applications is a topic of concern since fuel variability can have a great impact on the reliability and performance of the burner design. Autoignition experiments for a wide range of likely fuel blends containing CH4 mixed with combinations of C2H6, C3H8, C4H10, C5H12, and H2 are planned in the authors’ shock-tube laboratory. However, testing every possible fuel blend and interaction is not feasible within a reasonable time and cost. To predict the surface response over the complete mixture domain, a special experimental design has been developed reducing the amount of ‘trials’ needed significantly from 243 to only 41 using the Box-Behnkin factorial design methodology. Kinetics modeling was used to obtain numerical results for this matrix of fuel blends when applied to autoignition at a temperature of 800 K and pressure of 17 atm. A further attempt was made to reduce the 41-test matrix to a 21-test matrix. This was done using special mixture experimental techniques, and the kinetics model was used to compare the smaller matrix to the expected results of the larger one. The new 21-Test matrix produced a numerical correlation that agreed well with the results from the 41-test matrix, indicating that the smaller matrix will provide the same autoignition information as the larger one with acceptable precision.

Effect of Change in Fuel Compositions and Heating Value on Ignition and Performance for Siemens SGT-400 Dry Low Emission Combustion System

2013 ◽  
Author(s):  
Kexin Liu ◽  
Pete Martin ◽  
Victoria Sanderson ◽  
Phill Hubbard
Keyword(s):  
Natural Gas ◽  
Fuel Composition ◽  
Test Results ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Fuel Flexibility ◽  
Low Emission ◽  
Burner Design ◽  
Industrial Gas Turbine

The influence of changes in fuel composition and heating value on the performance of an industrial gas turbine combustor was investigated. The combustor tested was a single cannular combustor for Siemens SGT-400 13.4 MW dry low emission (DLE) engine. Ignition, engine starting, emissions, combustion dynamics and flash back through burner metal temperature monitoring were among the parameters investigated to evaluate the impact of fuel flexibility on combustor performance. Lean ignition and extinction limits were measured for three fuels with different heat values in term of Wobbe Index (WI): 25, 28.9 and 45 MJ/Sm3 (natural gas). The test results show that the air fuel ratio (AFR) at lean ignition/extinction limits decreases and the margin between the two limits tends to be smaller as fuel heat value decreases. Engine start tests were also performed with a lower heating value fuel and results were found to be comparable to those for engine starting with natural gas. The combustor was further tested in a high pressure air facility at real engine operating conditions with different fuels covering WIs from 17.5 to 70 MJ/Sm3. The variation in fuel composition and heating value was achieved in a gas mixing plant by blending natural gas with CO2, CO, N2 and H2 (for the fuel with WI lower than natural gas) and C3H8 (for the fuel with WI higher than natural gas). Test results show that a benefit in NOx reduction can be seen for the lower WI fuels without H2 presence in the fuel and there are no adverse impacts on combustor performance except for the requirement of higher fuel supply pressure, however, this can be easily resolved by minor modification through the fuel injection design. Test results for the H2 enriched and higher WI fuels show that NOx, combustion dynamics and flash back have been adversely affected and major change in burner design is required. For the H2 enriched fuel, the effect of CO and H2 on combustor performance was also investigated for the fuels having a fixed WI of 29 MJ/Sm3. It is found that H2 dominates the adverse impact on combustor performance. The chemical kinetic study shows that H2 has significant effect on flame speed change and CO has significant effect on flame temperature change. Although the tests were performed on the Siemens SGT-400 combustion system, the results provide general guidance for the challenge of industrial gas turbine burner design for fuel flexibility.

An Activity-Theoretical Method for Studying User Participation in IS Design

2003 ◽  
Vol 42 (04) ◽  
pp. 398-404 ◽  
Author(s):  
J. Lehenkari ◽  
S. Hyysalo
Keyword(s):  
Design Process ◽  
Historical Analysis ◽  
Theoretical Method ◽  
User Participation ◽  
Design Work ◽  
Conceptual Tool ◽  
User Groups ◽  
Near Future ◽  
Is Design

Summary Objectives: This paper aims to present an activity-theoretical method for studying the effects of user participation in IS development. Methods: This method is developed through a case study of the process of designing a diabetes database. Results and Conclusions: The method consists of a historical analysis of the design process, an ethno-graphical study of the use of the database, and researcher-driven interventions into the on-going user-producer interaction. In the historical analysis, we study particularly which user groups of the database have influenced the design work and which perspectives need to be incorporated into the design in the near future. An analytical model consisting of perspectives on local design, particular technology, and societal domain is introduced as a conceptual tool for this analysis. We also introduce the possibility of employing the historical analysis in guiding an ethno-graphical study of the user sites and researcher-driven interventions, which provide the participants with tools for improving their design process.

Spectrophotometric reductions with an IBM 1620

1966 ◽  
Vol 24 ◽  
pp. 116-117
Author(s):  
P.-I. Eriksson
Keyword(s):  
Astronomical Data ◽  
Spectrophotometric Data ◽  
Electronic Computers ◽  
The University ◽  
Near Future

Nowadays more and more of the reductions of astronomical data are made with electronic computers. As we in Uppsala have an IBM 1620 at the University, we have taken it to our help with reductions of spectrophotometric data. Here I will briefly explain how we use it now and how we want to use it in the near future.

Recent developments in automated Transmission Electron MI

1989 ◽  
Vol 47 ◽  
pp. 46-47
Author(s):  
W.J. de Ruijter ◽  
P. Rez ◽  
David J. Smith
Keyword(s):  
Image Analysis ◽  
Computer Image ◽  
Lens Design ◽  
Computer Image Analysis ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Recent Developments ◽  
On Line ◽  
Routine Procedures ◽  
Near Future

There is growing interest in the on-line use of computers in high-resolution electron n which should reduce the demands on highly skilled operators and thereby extend the r of the technique. An on-line computer could obviously perform routine procedures hand, or else facilitate automation of various restoration, reconstruction and enhan These techniques are slow and cumbersome at present because of the need for cai micrographs and off-line processing. In low resolution microscopy (most biologic; primary incentive for automation and computer image analysis is to create a instrument, with standard programmed procedures. In HREM (materials researc computer image analysis should lead to better utilization of the microscope. Instru (improved lens design and higher accelerating voltages) have improved the interpretab the level of atomic dimensions (approximately 1.6 Å) and instrumental resolutior should become feasible in the near future.

DNA methylation in satellite repeats disorders

2019 ◽  
Vol 63 (6) ◽  
pp. 757-771 ◽  
Author(s):  
Claire Francastel ◽  
Frédérique Magdinier
Keyword(s):  
Dna Methylation ◽  
Human Genome ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Satellite Repeats ◽  
Tremendous Progress ◽  
Genes Encoding ◽  
Dna Elements ◽  
Near Future

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.

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