| 1. |
- Marklund, Pär, et al.
(författare)
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Lead-free 22lr ammunition for sport shooting: A simple implementation or a huge challenge?
- 2024
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part P. - : Sage Publications. - 1754-3371.
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Tidskriftsartikel (refereegranskat)abstract
- In Europe it is approximated that around six million people are active in sport shooting. Currently, most bullets are manufactured out of lead which in many cases is combined with a copper jacket. There are several reasons for using lead; lead is relatively cheap, soft, and has a high density, and is therefore often the ideal material for bullets. Currently, the EU is seeking a restriction or ban on the use of lead in firearm bullets, with the main motivation that hunting with lead bullets might result in lead poisoning of both animals and people. The proposed lead ban will also have a major impact on sport shooting, as it is likely to be subjected to the same regulations. One caliber that has been shown to be very difficult to produce as a lead-free alternative is 22lr (long rifle), which today is the most common caliber for sport shooting in many disciplines. Today, there are not many scientific investigations available which show the performance of lead versus lead-free ammunition in caliber 22lr, even though it would make sense to investigate the possibilities of designing lead-free ammunition before a possible lead ban is further discussed. In this work the performance of two common lead-free 22lr-cartridges is evaluated and shown in comparison with existing lead-based ammunition, with a primary focus on sport shooting. Performance has been evaluated under both summer and winter conditions to cover different sports shooting disciplines. The results of this study clearly show the difficulty of finding lead-free 22lr cartridges with acceptable performance on the market today. In fact, the performance of the tested lead-free ammunition is so poor that the EU’s proposed lead ban could completely ruin shooting as a sport due to a lack of functioning ammunition.
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| 2. |
- Dittes, Nicholas J., 1987-, et al.
(författare)
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Corrosion Sensor for Water-Contaminated Grease
- 2020
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Ingår i: Tribology Transactions. - : Taylor & Francis. - 1040-2004 .- 1547-397X. ; 63:5, s. 891-896
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Tidskriftsartikel (refereegranskat)abstract
- A simple and inexpensive corrosion sensor has been manufactured to study the corrosion rate of new and water contaminated lubricating grease using a galvanic cell. The galvanic charge is developed between ENIG (electroless nickel immersion gold) and zinc, manufactured by selectively plating on a custom manufactured interdigitated PCB (printed circuit board). This paper shows the methodology in using this concept for any application which may require quantifying the corrosivity of a liquid or semisolid which could be applied to the surface of the sensor. Water contamination is a problem in many grease lubricated machine components, so a sensor concept was developed and a correlation between water content and the corrosion rate is shown. This method could be used to precisely study the corrosion rate of aged or contaminated lubricants and could potentially be used as a cheap and simple way to estimate water contamination of grease. To the knowledge of the authors, this sensor concept has not been used in industry or literature.
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| 3. |
- Dittes, Nicholas, 1987-, et al.
(författare)
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Automated Dielectric Thermoscopy Characterization of Water Contaminated Grease
- 2019
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Ingår i: Tribology Transactions. - : Taylor & Francis. - 1040-2004 .- 1547-397X. ; 62:5, s. 859-867
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Tidskriftsartikel (refereegranskat)abstract
- Machine maintenance is important for improving machine uptime, reliability, and reducing costs. Grease is used in most rolling element bearings, and one common failure criterion is water contamination, so developing a sensor which can detect water content automatically without human input could be a useful endeavor. The temperature dependence on the dielectric properties of water-contaminated grease is investigated in this paper with computer logged instrumentation. This method has been termed Dielectric Thermoscopy (DT). Several off the shelf (two lithium, one lithium complex, and two calcium sulphonate complex) and one unadditivized lithium grease are tested with varying amounts of water contamination from 0% to approximately 5%. Another grease is tested with small increments of added water from 0% to 0.97% to test the resolution of the measurement. The purpose is to use the capacitance temperature slope (termed dielectric thermoscopy) to show correlations to the water content of the grease sample and investigate if any grease types will pose problems in the measurement. A small, custom made fringe field capacitance sensor with an integrated temperature sensor has been used for this characterization and data is logged automatically with laboratory equipment and a PC. A useable and positive correlation to water content and the DT measurement of roughly 0.5 pF per 10 °C and percentage of water is found, although it was found that some greases have different behavior than others.
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| 4. |
- Dittes, Nicholas, et al.
(författare)
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Dielectric Thermoscopy Characterization of Water Contaminated Grease
- 2018
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Ingår i: Tribology and Lubrication Technology. - : Society of Tribologists and Lubrication Engineers (STLE). - 1545-858X. ; 61:3, s. 393-402
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence on the dielectric properties of water-contaminated grease is investigated in this article. The purpose of this investigation was to identify the dielectric properties that could be measured to differentiate varying levels of water contamination in calcium sulfonate complex (CaS-X) grease with three different test cells with the purpose of eventually developing a grease condition sensor. Measuring the change in dielectric constant over a small temperature change yielded useful estimations of water content and amount of grease where the added water content ranged from 0.22% to about 5.5%. Additionally, other parameters such as incomplete fill/coverage of the sensors were investigated as a prestudy. The results from this set of experiments show that the measurement has potential to be developed into a condition monitoring sensor in the future.
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| 5. |
- Dittes, Nicholas, 1987-, et al.
(författare)
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Optical Attenuation Characterization of Water Contaminated Lubricating Grease
- 2018
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Ingår i: Tribology Transactions. - : Taylor & Francis. - 1040-2004 .- 1547-397X. ; 61:4, s. 726-732
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Tidskriftsartikel (refereegranskat)abstract
- Water-contaminated grease samples are investigated with attenuation spectra in the visible and near-infrared (NIR) regions in this article. The purpose of this investigation was to identify a model with optical attenuation spectra such that the water content of grease samples could be characterized with a simple measurement setup using common methodology from the field of instrumental chemistry. The ratio between two chosen wavelengths of light appears to approximate the water content of grease samples with an acceptable coefficient of determination using a methodology to show what can potentially be done to develop condition monitoring tools. To illustrate the outlined method, a prestudy of grease aging and oxidation levels is also investigated to show that other variables do not significantly change the measurement.
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| 6. |
- Dittes, Nicholas, et al.
(författare)
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Mixing Grease with Water
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this paper is to convey a simple and effective method to mix water with grease and verify the homogeneity of the mixture using Karl-Fischer (KF) titration as the analysis tool. This is required to better develop a future water in grease sensor for on-line condition monitoring. This paper will also attempt to investigate how well KF titration functions as a tool for measuring water content in grease. Additional investigations include how the water content varies with time in grease samples open to atmosphere at different temperature. This research verifies a simple grease mixing method and investigates the water transport in water contaminated grease samples.
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| 7. |
- Jonasson, Hanna, et al.
(författare)
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Oxygen saturation, red blood cell tissue fraction and speed resolved perfusion — A new optical method for microcirculatory assessment
- 2015
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Ingår i: Microvascular Research. - : Academic Press. - 0026-2862 .- 1095-9319. ; 102, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a new fiber-optic system that combines diffuse reflectance spectroscopy (DRS) and laser Doppler Flowmetry (LDF) for a multi-modal assessment of the microcirculation. Quantitative data is achieved with an inverse Monte Carlo algorithm based on an individually adaptive skin model. The output parameters are calculated from the model and given in absolute units: hemoglobin oxygen saturation (%), red blood cell (RBC) tissue fraction (%), and the speed resolved RBC perfusion separated into three speed regions; 0–1 mm/s, 1–10 mm/s and above 10 mm/s (% mm/s). The aim was to explore microcirculatory parameters using the new optical method, integrating DRS and LDF in a joint skin model, during local heating of the dorsal foot and venous and arterial occlusion of the forearm in 23 healthy subjects (age 20–28 years). There were differences in the three speed regions in regard to blood flow changes due to local heating, where perfusion for high speeds increased the most. There was also a high correlation between changes in oxygenation and changes in perfusion for higher speeds. Oxygen saturation at baseline was 44% on foot, increasing to 83% at plateau after heating. The larger increase in perfusion for higher speeds than for lower speeds together with the oxygenation increase during thermal provocation, shows a local thermoregulatory blood flow in presumably arteriolar dermal vessels. In conclusion, there are improved possibilities to assess microcirculation using integrated DRS and LDF in a joint skin model by enabling both oxygenation and speed resolved blood flow assessment simultaneously and in the same skin site. Output parameters in absolute units may also yield new insights about the microcirculatory system.
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| 8. |
- Pettersson, Anders
(författare)
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Augmenting L1 Adaptive Control of Piecewise Constant Type to Aerial Vehicles
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In aerial vehicle control design, the industrial baseline is to use robust control methods together with gain-scheduling to cover the full airspeed and altitude flight envelope. An adaptive controller could possibly add value by increasing performance while keeping robustness to deviation from nominal assumptions. In this thesis L1 adaptive control is studied and evaluated as it is applied to a pitch-unstable fighter aircraft. The recently developed L1 adaptive control method originates from aerospace adaptive control problems and achieves fast adaptation while robust stability to bounded plant parameter changes is claimed. Even though large adaptation gains create large and rapidly varying internal signals, the L1 adaptive controller output is limited in amplitude and frequency, since a low-pass filter directly at the output, is used to make the controller act within the control channel bandwidth. An L1 adaptive controller of piecewise constant type has been applied to a fighter aircraft by augmenting a baseline linear state feedback controller. Once some experience is gained, it is relatively straightforward to apply this design procedure because only a few controller parameters need tuning. To design an L1-controller for roll-pitch-yaw-motion of an aerial vehicle, a five-state reference system with desired dynamics was created and five bandwidths of low-pass filters were tuned. The L1-controller activates when the vehicle aided by the state feedback controller deviates from the reference dynamics resulting in better reference following. Load disturbance rejection was improved by the L1-controller augmentation. This comes at the cost of having high frequency control signals fed into the plant. The L1 adaptive controller is in its original design sensitive to actuator limitations and to time delays when compared to the baseline controller. Introducing nonlinear design elements corresponding to actuator dynamics (e.g. rate limits) makes tuning easier if such dynamics interfere with the reference system dynamics. Sensitivity to known time delays can be reduced using prediction in a state observer. With these additions to the design, the L1-controller augmentation can be tuned to achieve improved nominal performance and robust performance when compared to a typical aeronautical linear state feedback controller. This was verified by simulations using a high fidelity model of the aircraft. Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and corresponding models can also be used as reference models in adaptive control. A method for aerial vehicle reference model design was developed, that makes it possible to find reference models that scale to the present flight condition and vehicle configuration. In some situations the closed-loop system obtained by L1 adaptive control is equivalent to linear systems. The architectures of these systems were investigated. An effort was made to understand and describe what fundamental characteristic of L1 adaptive controllers make them suitable for aeronautical applications. With the L1-controller, performance and robustness was increased when compared to the baseline controller. It is possible to add L1-controller characteristics gradually to a linear state feedback design, which is something that this thesis recommends to aerospace industry.
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| 9. |
- Pettersson, Anders, et al.
(författare)
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Nonlinear Feedforward and Reference Systems for Adaptive Flight Control
- 2013
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Ingår i: 2013 AIAA Guidance, Navigation, and Control Conference. - Reston, Virginia : American Institute of Aeronautics and Astronautics.
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Konferensbidrag (refereegranskat)abstract
- Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and the same models can also be used as reference models in adaptive control. A method for designing the reference models is presented in the paper. By exploiting the structure of the equations describing air vehicles it is possible to find reference models that scale to the present flight condition and vehicle configuration. Such reference systems are derived for flying vehicles in a generic manner, suitable for both winged aircraft and missiles. The same type of reference systems are also used to create trajectories for feedforward signals that compensate known plant non-linearities.
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| 10. |
- Kuttah, Dina K, 1975-, et al.
(författare)
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Production and Processing of Reclaimed Asphalt : Selected case studies
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Deliverable 4.4 concerns selected case studies under Task 4.2 of the work program of Work Package 4 of the 7th EU framework project Re-Road which concerns the recycling of reclaimed asphalt (RA). The objective is to reach the optimum use of RA in new asphalt pavement – particular for the use in surface layers for high capacity roads where high percentages of RA can be very beneficial – not only for the reuse of the bituminous binders but also for the savings in natural resources with respect to the aggregates.The objectives and issues for WP4 have been the production and handling of reclaimed asphalt and its introduction into the mixing plant. In this work package Task 4.2 and 4.3 have parallel objectives for their separate issues. Task 4.2 concerns handling and pre-processing of RA, while Task 4.3 has been dealing with the introduction of RA into the mixing plant. Both tasks have, after surveys and questionnaires which were reported in Deliverable 4.2 of this project, have been trying to establish selected case studies which could highlight special issues or try to focus on detailed subjects which the survey and questionnaire in Deliverable 4.2 has shown that additional information could be helpful to meet the overall objective of the Re-Road project.The Deliverable 4.4 deals with the following selected case studies:Production of reclaimed asphalt from Danish Motorways and associated conditions for milling and maintenanceThe Swedish Experience Regarding the Removal, Storage and Processing of Reclaimed AsphaltSwedish case of environmental impact of temporary storage of tar containing reclaimed asphaltSlovene case study of RA productionPre-processing (crushing/sieving) of reclaimed asphalt by subcontractors at the asphalt plants or processing units in Denmark
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