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| 2. |
- Jagtap, Santosh, et al.
(författare)
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Design for the BOP and TOP markets: Strategies used by the design students
- 2013
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Konferensbidrag (refereegranskat)abstract
- The base (BOP) and the top (TOP) of the world income pyramid represent the poor people and the people from developed countries, respectively. About two-fifths of the world population can be categorized as poor. Poverty is a trap because children born to poor parents are likely to grow up to be poor adults. In recent years, a poverty reduction approach that combines business development with poverty alleviation has received attention. The design of products for the BOP is an important ingredient of this poverty reduction approach. While companies are beginning to address the product needs of the BOP, there is limited practical and theoretical knowledge to support them. The current understanding of the design for the BOP is limited. This study aims at exploring the differences between the design strategies used by the industrial design students in designing products for the BOP and TOP markets. The results indicate the differences between their design strategies (i.e. problem driven strategy, solution driven strategy) in designing products for the BOP and TOP markets. We have discussed the implications of the findings for design practice and education. In particular, we have discussed how university-based design projects for the BOP can help in developing students’ different design skills.
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| 3. |
- Jagtap, Santosh, et al.
(författare)
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Ideation Metrics: Interdependency between Average Novelty and Variety
- 2012
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Ingår i: DS 70: Proceedings of DESIGN 2012, the 12th International Design Conference, Dubrovnik, Croatia. - 1847-9073. - 9789537738174 ; , s. 1881-1892, s. 1881-1892
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined The importance of ideation in the conceptual design phase has been widely accepted. Shah et al. (2003) developed four key metrics for evaluating a designer’s exploration and expansion of design space. The four metrics are: novelty, variety, quality, and quantity of designs. The mean of novelty scores of ideas in a set (i.e. Average Novelty - AN) has also been used in some ideation studies. However, many of the studies that have computed AN and variety, have not examined the interdependency between them. This research aims at examining the interdependency between AN and variety.
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| 4. |
- Sjöberg, Katrin, et al.
(författare)
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Measuring and using the RSSI of IEEE 802.11p
- 2010
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Ingår i: 17th World Congress on Intelligent Transport Systems, ITS 2010, Busan, South Korea, 25-29 October 2010.
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Konferensbidrag (refereegranskat)abstract
- The scalability of intelligent transport systems (ITS) applications is difficult to test in a field operational test (FOT) due to the high number of ITS equipped vehicles required. Therefore, computer simulations for evaluating different wireless communication technologies for ITS different applications can serve as a complement. In this paper we present results from lab measurements conducted on the CVIS hardware platform equipped with the upcoming standard IEEE 802.11p. We have measured the packet error rate versus the signal-to-noise ratio (SNR) for different packet lengths. This lab measurement is the first step towards an outdoor measurement campaign which also considers interference. The outdoor measurements will then be fed into a computer simulator together with a realistic channel model for evaluating the scalability of VANETs in a highway scenario.
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| 5. |
- Almström, Peter, 1972, et al.
(författare)
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Achieving Sustainable Production through Increased Utilization of Production Resources
- 2011
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Ingår i: Proceedings of the 4th Swedish Production Symposium, SPS11, Lund, May 3-5, 2011. ; , s. 398-406
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Konferensbidrag (refereegranskat)abstract
- There seems to be a quite divergent view on sustainable production, mainly based on the perspective applied. From a global perspective, every kind of material consumption and growth is basically unwanted and should be minimized. This reflects in economic sustainability parameters that point towards producing as little as possible and socialparameters pointing at eliminating abuse of human rights etc. On the other hand, international summits on sustainability have stated that it is a human right to have a certain standard of living, which implies increase in production but with less resource consumption. This global perspective is however not very helpful when focusing on more local level, for example Swedish manufacturing industry. To achieve a long-term jobsecurity the manufacturing companies need to be long-term prosperous. Further, to be able to maintain profitability levels, manufacturing companies need to continuouslyincrease productivity. Utilization deals with using production equipment in a cost efficient way and this article will highlight how utilization affects different aspects of sustainable production, the link between utilization and productivity, as well as practical considerations when improving utilization in manufacturing industry.
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| 6. |
- Claesson, Johan, 1943, et al.
(författare)
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A load-aggregation method to calculate extraction temperatures of borehole heat exchangers
- 2012
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Ingår i: ASHRAE Transactions. - 0001-2505. ; 118:1, s. 530-539
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Konferensbidrag (refereegranskat)abstract
- Hourly simulations of extraction fluid temperatures from borehole heat exchangers tend to be very time consuming. A new load aggregation scheme to perform long-term simulations of borehole heat exchangers is presented. The starting point is the step-response function for the considered borehole heat exchanger and the corresponding long sequence of cells, each with a load and a weighting factor. On the first level, the original weighting factors are kept. On the following levels, 2, 4, 8, etc., the weighting factors are lumped together. The lumped weighting factors are obtained directly from the step-response function. The number of cells to be lumped together is chosen so that the extraction temperatures using lumped weighting factors give a sufficiently good approximation of the non-aggregated scheme. The new scheme is applied to a test case to simulate extraction fluid temperature over a 20-year time period. Comparison of the results from the new scheme with the non-aggregated setting shows that the new scheme can perform very accurate and fast simulations of borehole heat exchangers.
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| 7. |
- Huang, Zhe, 1986, et al.
(författare)
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Characterization and application of forced cooling channels for traction motors in HEVs
- 2012
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Ingår i: 2012 20th International Conference on Electrical Machines, ICEM 2012; Marseille; France; 2 September 2012 through 5 September 2012. - 9781467301428 ; , s. 1212-1218, s. 1212-1218
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Konferensbidrag (refereegranskat)abstract
- This paper presents the characterization of forced cooling channels with three different shapes which are applied in traction motors mounted in Hybrid Vehicles (HEVs) or Zero Emission Vehicles (ZEVs). Generally, there are two different positions of forced cooling channels in electric motors. One way is by drilling holes or cutting cooling channels inside the housing, which is called indirect cooling approach. The other way is to cut the cooling channels at the edges of housing or/and stator back to form direct cooling channels, where the coolant is in direct contact with the hot stator back. In both cases, choosing suitable shapes of cooling channels are necessary. In this paper, both heat transfer coefficient hf and pump power Wpump are calculated. The dimensional parameters are easily understood and also used for further thermal analysis of the completed machine by either Finite Element Analysis (FEA) or lumped parameter approaches. In addition, the dimensionless parameters Nusselt number Nu and Darcy friction factor f are evaluated with the aim to understand the characterizations for different channels. These parameters are easily used for further cooling channels optimization. In the end, the thermal analyses for a stator segment with three different shaped channels are carried on by applying the calculated results from Computational Fluid Dynamics (CFD) simulations.
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| 8. |
- Nordebo, Sven, et al.
(författare)
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Fisher information analysis and preconditioning in electrical impedance tomography
- 2010
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Ingår i: Journal of Physics: Conference Series 224 (2010), 1742-6588. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; , s. 012057-
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Konferensbidrag (refereegranskat)abstract
- An adjoint field approach is used to formulate a general numerical framework for Fisher information based sensitivity analysis in electrical impedance tomography. General expressions are given for the gradients used in standard least squares optimization, i.e., the Jacobian related to the forward problem, and it is shown that these gradient expressions are consistent with commonly used electrode models such as the shunt model and the complete electrode model. By using the adjoint field formulations together with a variational analysis, it is also shown how the computation of the Fisher information can be integrated with the gradient calculations used for optimization. It is furthermore described how the Fisher information analysis and the related sensitivity map can be used in a preconditioning strategy to obtain a well balanced parameter sensitivity and improved performance for gradient based quasi-Newton optimization algorithms in electrical impedance tomography. Numerical simulations as well as reconstructions based on experimental data are used to illustrate the sensitivity analysis and the performance of the improved inversion algorithm in a four-electrode measurement set-up.
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| 9. |
- Abou-Taouk, Abdallah, 1982, et al.
(författare)
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CFD INVESTIGATION OF SWIRL-STABILIZED FLEXI-FUEL BURNER USING METHANE-AIR MIXTURE FOR GAS TURBINES
- 2011
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Ingår i: International Society for Airbreathing Engines, ISABE, Gothenburg, 2011. ; 1, s. 160-172
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Konferensbidrag (refereegranskat)abstract
- Combustion modeling based on a multi-step global reaction mechanism [1] is applied to CFD (Computational Fluid Dynamics) analysis of a scaled swirl-stabilized 4th generation premixed DLE (Dry Low Emission) burner for gas turbines. The flexi-fuel burner consists of a MAIN pre-mixed flame, a premixed PILOT flame and a confined RPL (Rich Pilot Lean) flame. Both steady-state RANS (Reynolds Averaged Navier Stokes) and hybrid URANS/LES (Unsteady RANS/Large Eddy Simulation) results have been computed. The results are compared with high quality experimental data in the form of emission data, PIV (Particle Image Velocimetry) data and OH-PLIF (Planar Laser Induced Fluorescence Imaging) from an atmospheric burner test rig at Lund University [2-3]. There is a good agreement between the CFD simulations and measurements of emissions, velocity field and flame visualization.
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| 10. |
- Sammak, Majed, et al.
(författare)
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Conceptual Design Of A Mid-Sized Semi-Closed Oxy-Fuel Combustion Combined Cycle
- 2011
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Ingår i: Proceedings of the ASME Turbo Expo 2011: Power for Land, Sea and Air, 2011, Vancouver, Canada. ; 4, s. 253-261
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Konferensbidrag (refereegranskat)abstract
- This paper presents the study of a mid-sized semi-closed oxy-fuel combustion combined cycle (SCOC-CC) with net power output around 108 MW. The paper describes not only the power balance and the performance of the SCOC-CC, but also the conceptual design of the SCOC turbine and compressor. A model has been built in the commercial heat and mass balance code IPSEpro to estimate the efficiency of semi-closed dual-pressure oxy-fuel combustion combined cycle using natural gas as a fuel. In order to obtain the real physical properties of the working fluids in IPSEpro, the code was linked to the NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP).The oxy-fuel turbine was modeled with the in-house Lund University package LUAX-T. Important features such as stage loading, loss modeling, cooling and geometric features were included to generate more accurate results. The oxy-fuel compressor has been modeled using a Chalmers university in-house tool for conceptual design of axial compressors. The conceptual design of the SCOC-CC process has a net efficiency of 47 %. The air separation unit and CO2 compression reduce the cycle efficiency by 10 and 2 percentage points, respectively.A single-shaft configuration was selected for the gas turbine simplicity. The rotational speed chosen was 5200 rpm and the turbine was designed with four stages. All stage preliminary design parameters are within ranges of established industrial axial turbine design limits. The main issue is the turbine exit Mach number; the stage must be lightly loaded in terms of pressure ratio to maintain the exit Mach number below 0.6. The compressor is designed with 18 stages. The current value of the product of the annulus area and the blade rotational speed squared (AN2) was calculated and found to be 40*10^6.
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