High-repetition-rate combustion thermometry with two-line atomic fluorescence excited by diode lasers

We report on kilohertz-repetition-rate flame temperature measurements performed using blue diode lasers. Two-line atomic fluorescence was performed by using diode lasers emitting at around 410 and 451 nm to probe seeded atomic indium. At a repetition rate of 3.5 kHz our technique offers a precision of 1.5% at 2000 K in laminar methane/air flames. The spatial resolution is better than 150 mu m, while the setup is compact and easy to operate, at much lower cost than alternative techniques. By modeling the spectral overlap between the locked laser and the probed indium lines we avoid the need for any calibration of the measurements. We demonstrate the capability of the technique for time-resolved measurements in an acoustically perturbed flame. The technique is applicable in flames with a wide range of compositions including sooting flames

Consumption based scenarios for Sweden - a basis for discussing new climate targets

Also available in Swedish: \ua0https://research.chalmers.se/publication/52652

Systems maps and analytical framework. Mapping food waste drivers across the food supply chain

This report generated 17 systems maps for five contrasting product types that were investigated along their supply chains. The system maps identify: (1) Product specific drivers: drivers specific to the selected food products at a specific stage of the supply chain); (2) Generic drivers: drivers which concern two or more selected products (e.g. labelling errors, limited shelf life etc.); (3) Systemic drivers: drivers that are interlinked with more than one step of the supply chain (e.g. minimum orders, last minute cancellation, lack of data and communication, minimum life on receipt criteria etc.). The cross cutting systemic drivers emphasized supply chain issues, e.g. regarding notably the interactions between the different businesses and unfair trading practices. The systems map approach also shed light on two key factors that impact drivers according to the product specificity: (1) Impacts of food waste drivers highly depend on the level of perishability and microbiological risk of food products. For example, less perishable food products such as frozen and canned products are more likely to be wasted because of product damage, labelling errors and/or equipment breakdown. More perishable and higher risk food products are more likely to be wasted when approaching the \u201cbest before\u201d date or because of supply and demand imbalances and poor information sharing along the supply chain. (2) Lack of communication and cooperation is a central drivers of food waste. The impacts of these are higher in more complex products/supply chains where trouble with one ingredient affects the whole product (e.g. prepared meals). Finally, the systems mapping shed light on drivers which were \u201chiding\u201d behind other drivers. For example, the question of date labelling is a well-known cause of waste for perishable products, but very often there are further drivers behind it (e.g. overstocking in the retail sector)

Huntingtin Aggregation Impairs Autophagy, Leading to Argonaute-2 Accumulation and Global MicroRNA Dysregulation

Many neurodegenerative diseases are characterized by the presence of intracellular protein aggregates, resulting in alterations in autophagy. However, the consequences of impaired autophagy for neuronal function remain poorly understood. In this study, we used cell culture and mouse models of huntingtin protein aggregation as well as post-mortem material from patients with Huntington’s disease to demonstrate that Argonaute-2 (AGO2) accumulates in the presence of neuronal protein aggregates and that this is due to impaired autophagy. Accumulation of AGO2, a key factor of the RNA-induced silencing complex that executes microRNA functions, results in global alterations of microRNA levels and activity. Together, these results demonstrate that impaired autophagy found in neurodegenerative diseases not only influences protein aggregation but also directly contributes to global alterations of intracellular post-transcriptional networks

The effect of eccentric training on pain and function in patients with chronic patellar tendinopathy : A systematic review

Syfte - Syftet med denna systematiska litteraturstudie var att sammanställa forskning som utvärderar effekten av excentrisk träning samt jämföra excentrisk träning med alternativ behandling på smärta och funktion vid kronisk patellar tendinopati. Frågeställningar 1. Vilken evidens finns idag för att excentrisk träning minskar smärta och förbättrar funktion hos personer med patellar tendinopati? 2. Vilken evidens finns idag för att excentrisk träning är mer effektiv gällande smärta och funktion jämfört med andra behandlingsstrategier hos personer med patellar tendinopati? Metod Sökning av litteratur gjordes i PubMed, Web of Science, Cinahl och AMED. 12 artiklar valdes ut för granskning enligt PEDro scale. Poängbedömningen omsattes till SBUs mall för bevisvärde för evidensgrad och sammanställdes i tabellform med rubrikerna syfte, urval, metod, statistik, resultat, slutsats och primära utfallsvariabler. Resultat Resultatet av denna litteraturstudie visar en indikation på att excentrisk träning minskar smärta och ökar funktion hos personer med patellar tendinopati. Jämfört med annan behandling är excentrisk träning lika effektivt som kirurgi, Heavy Slow Resistance och mer effektiv än kortisoninjektion vid långtidsuppföljning. En artikel hade högt bevisvärde och elva medelhögt. Slutsats Nuvarande forskning ger en indikation på att excentrisk träning ger en minskning av smärtan och ökad funktion hos personer med patellar tendinopati, dock kan man om möjligheten finns använda sig av andra behandlingsmetoder som visat sig ge samma effekt. För att säkerställa effekten gentemot andra behandlingsmetoder behövs fler studier med hög kvalité som jämför samma metoder. I dagsläget är det för få studier som faktiskt jämför samma saker vilket gör det svårare att med säkerhet säga att excentrisk träning är bättre än annan behandling.Aim - The purpose of this systematic review was to compile research evaluating the effect of eccentric training and compared with alternative therapy, on pain and function in patients with chronic patellar tendinopathy. Method - Search of the literature was done in PubMed, Web of Science, Cinahl and AMED. 12 articles were selected for review using the PEDro scale. Points assessment were traded with SBU template probative value of evidence level and summarized in tabular form. Results - The results of this study showed that eccentric training reduces pain and increases function of patients with patellar tendinopathy. Compared to other treatments eccentric training is as effective as surgery, Heavy Slow Resistance and more effective than cortisone injection at long term follow-up. Also more effective than friction and ultrasound. One article had high quality and the rest medium quality. Conclusions -Current research provides an indication that eccentric exercise results in a decrease in pain and improved function in patients with patellar tendinopathy, however, the use of other therapies has proven to give the same effect and can be used if there is a possibility to. To ensure efficacy against other treatments more studies with high quality comparing the same methods are needed. In the current situation there are too few studies that actually compare the same things which make it difficult to say with certainty that eccentric training is better than any other treatment

Development of Time Resolved Laser Imaging Techniques for Studies of Turbulent Reacting Flows

In the present thesis the development and application of a novel laser diagnostic system for high speed spectroscopic imaging of turbulent combustion phenomena is presented. The system is capable of recording sequences of up to 8 images with a separation between consecutive images as short as microseconds. The system allows a number of established laser diagnostic techniques to be used, extending them into the time resolved regime. For the first time it has thus become possible to observe the influence of fluid motion or reaction chemistry on flame structure in a direct, time resolved, fashion. The high speed diagnostic system has been used to study flame species and fuel distributions with a high temporal resolution in jet flames, combustion cells and in IC engines. In jet flames various flame instability mechanisms, like local flame extinction and flame lift-off have been studied. Large scale structures have been observed and tracked in time, using time resolved planar laser induced fluorescence (PLIF) imaging of the OH radical. Individual extinction phenomena have been studied in further detail by simultaneous measurements of the velocity field at the flame front, allowing correlations between flow and flame structures to be made. Vortices impinging on the flame front from the fuel side were found to be the main extinction mechanism, and the time scale of the extinction process could be estimated. High speed imaging has also been applied to study novel combustion engine concepts, like the homogeneous charge compression ignition (HCCI) engine. True single-cycle resolved measurements allows the evolution of single fuel injection, ignition or combustion events to be followed in time, and cycle-to-cycle variations of complex phenomena to be studied. In an HCCI engine the appearance and growth of multiple auto-ignition kernels was observed. Following ignition the fuel was found to be consumed gradually, at different rates in different regions, and not through propagating flame fronts as is the case in spark ignition engines. By rapidly displacing the eight laser beams through a measurement volume using a scanning mirror, three-dimensional (3-D) measurements also become possible. This technique has been demonstrated in both flames and engines, allowing flame topology or 3-D concentrations gradients to be studied. In addition to the experimental work, advanced image processing routines have also been developed and applied for automatic data enhancement and analysis

Drum Brake Squeal

Drum brake squeal is a common discomfort. The main goal of this thesis is to investigate the mechanisms that generate drum brake squeal and to create a base for the search for solutions. A series of steps towards the understanding of these mechanisms are taken. Firstly, a simple model for friction-induced vibration is presented. The solutions to this model might be unstable in spite of a constant coefficient of friction. The essential thing observed is that a coupling between different modes is necessary to form instabilities. The coupling is shown to be between two translational degrees of freedom. Secondly, the mathematical model for friction-induced vibration is refined to take the flexibility of the drum, shoes and linings into account. This model is used to study the mechanisms that couple modes. The analysis shows that there are four mechanisms present in generating drum brake squeal. These mechanisms all occur owing to lining deformations, and the instability type is given the name "Lining Deformation Induced Instabilities". The mechanisms create waves that move in different directions. In a squealing brake, all the waves are superposed, which leads the solution towards a standing wave. A standing wave or synchronous vibration is always stable, and if a pure synchronous vibration is created, the noise would be eliminated at the source. The experimental partt of the investigation concerns the measurement of the vibration of a drum brake. The deflection shape is measured in operation, i.e. while the vehicle is running on a test ground. The deflection shape covers radial vibrations of the drum as well as radial and tangential vibrations of the leading shoe. The accelerometers are distributed both axially and tangentially on both the shoe and the drum. Finally, a finite element model for friction-induced vibration and noise generation is used to study the influence of different self-excitations on drum brake squeal. The model is semi-three-dimensional, with a two-dimensional drum and three-dimensional shoes. A contact element is derived that takes the friction variation into account as well as follower forces and negative .my.-velocity slope. For the brake analyzed, the results are: "Stick-Slip" is impossible for vehicle speeds over 0.04 km/h. The destabilizing effect of the "Negative .my.-Velocity Slope" is less than the stabilizing effect of the material damping of the parts. "Self-Locking" is shown to be impossible. The "Lining Deformation Induced Instability" type results in great squeal propensity. The instabilities from "Follower Forces" are negligible. The rotation of the drum gives frequency shifts that stabilize the brake. The frequencies and mode shapes generated from the model with the lining deformation induced instability type show very good agreement with the measured ones. With the knowledge of the mechanisms behind and characteristics of drum brake squeal, a set of solution classes is outlined. A series of examples is given to show the usefulness of such classes as an aid in the creative process of generating solution principles

Drum Brake Squeal

Drum brake squeal is a common discomfort. The main goal of this thesis is to investigate the mechanisms that generate drum brake squeal and to create a base for the search for solutions. A series of steps towards the understanding of these mechanisms are taken. Firstly, a simple model for friction-induced vibration is presented. The solutions to this model might be unstable in spite of a constant coefficient of friction. The essential thing observed is that a coupling between different modes is necessary to form instabilities. The coupling is shown to be between two translational degrees of freedom. Secondly, the mathematical model for friction-induced vibration is refined to take the flexibility of the drum, shoes and linings into account. This model is used to study the mechanisms that couple modes. The analysis shows that there are four mechanisms present in generating drum brake squeal. These mechanisms all occur owing to lining deformations, and the instability type is given the name "Lining Deformation Induced Instabilities". The mechanisms create waves that move in different directions. In a squealing brake, all the waves are superposed, which leads the solution towards a standing wave. A standing wave or synchronous vibration is always stable, and if a pure synchronous vibration is created, the noise would be eliminated at the source. The experimental partt of the investigation concerns the measurement of the vibration of a drum brake. The deflection shape is measured in operation, i.e. while the vehicle is running on a test ground. The deflection shape covers radial vibrations of the drum as well as radial and tangential vibrations of the leading shoe. The accelerometers are distributed both axially and tangentially on both the shoe and the drum. Finally, a finite element model for friction-induced vibration and noise generation is used to study the influence of different self-excitations on drum brake squeal. The model is semi-three-dimensional, with a two-dimensional drum and three-dimensional shoes. A contact element is derived that takes the friction variation into account as well as follower forces and negative .my.-velocity slope. For the brake analyzed, the results are: "Stick-Slip" is impossible for vehicle speeds over 0.04 km/h. The destabilizing effect of the "Negative .my.-Velocity Slope" is less than the stabilizing effect of the material damping of the parts. "Self-Locking" is shown to be impossible. The "Lining Deformation Induced Instability" type results in great squeal propensity. The instabilities from "Follower Forces" are negligible. The rotation of the drum gives frequency shifts that stabilize the brake. The frequencies and mode shapes generated from the model with the lining deformation induced instability type show very good agreement with the measured ones. With the knowledge of the mechanisms behind and characteristics of drum brake squeal, a set of solution classes is outlined. A series of examples is given to show the usefulness of such classes as an aid in the creative process of generating solution principles