ABS and Anti-skid on a LEGO car : A project in Embedded Systems

This work is the result of a course project in Embedded Systems. The goal was to implement a whee-slip control system on a LEGO car using a microcontroller. The car allows front-wheel or back-wheel driven configuration. Experimental results are presented for dry and wet surfaces

What can we learn from COVID-19 as a form of public pedagogy?

This paper aims to investigate the corona-crisis as a large-scale, unplanned and unintended global experiment of ‘public pedagogy’. An investigation is focused on touching upon emergent questions such as: What does our experience of the crisis brought about by the emergence of this specific virus tell us about our assumptions of learning and of public engagement with an issue as a form of public pedagogy? We bring into play transactional theory of teaching and learning, as well as Jan Masschelein’s notion of pedagogical milieu of study and Timothy Morton’s concept of hyperobject to conceptualize what we can learn from COVID-19 in terms of teaching and learning. (DIPF/Orig.

Evaluation of transgenic Campanula carpatica plants

In Campanula carpatica, the general problem is that the flowers are very sensitive to exogenous ethylene. Flowers that are exposed to ethylene wilt in two to three days. Treating the plants with anti-ethylene compounds can prevent the problems with ethylene. However, these compounds are very expensive and environmentally dangerous. The advances in genetic engineering and transformations with the mutant etr1-1 gene in, e.g. carnations and petunia have led to plants of the Campanula carpatica cultivars 'Blue Uniform' being transformed with the gene etr1-1 in order to resist the effects of ethylene. The transformation of the plants resulted in transformed shoots that were grown in tissue culture and later planted in greenhouses. These different shoots were called lines and were given different numbers. The transformed plants were tested for their sensitivity to ethylene. A total of 20 different transgenic lines of the Campanula carpatica were evaluated. To determine whether there were any differences in plant morphology after they had been transformed with the etr1-1 gene, morphological studies were performed. For the transformed plant to be suitable for use in further plant breeding, the flowers, and especially the pollens, had to be investigated. Pollen was tested for viability, growth of the pollen tube, and finally, crossing was done to prove the viability. The lines were divided into three groups depending on percentage viability or percentage of grown pollen tubes. Group A included lines Aglo 2, Aglo 3, Aglo 4 and SF 28-1. Group B included lines SF 15-1 and 'Blue Uniform' control. Group C included line SF 13-1. To confirm that the gene etr1-1 was inserted in the plants, they were also tested using polymerase chain reaction (PCR). ELISA analyses were performed to investigate the presence of nptII in the transformed lines. The final results revealed that the lines SF 15-1, SF 15-1c, SF 15-1de, SF 15-4 and GH 4 had a low sensitivity to ethylene. These plants had no morphological differences. However, the lines Aglo 1, Aglo 2, Aglo 3, Aglo 4 and Aglo 8.3 lacked hairs under the leaves and on the stem parts. Line SF 11-2 displayed a different pattern of plant growth with a pointier growth behaviour of the buds and leaves, while the lines SF 13-1 and SF 13-1a grew much taller than the other lines. The lines SF 15-1, SF 15-1c, SF 15-1de, SF 15-4 and GH 4 (especially SF 15-1) had fertility values that were close to the control plants. In the PCR, lines SF 15-1, SF 15-1c, SF 15-1de, SF 15-4, SF 13-1, SF 13-1a and GH 4 amplified the gene etr1-1. In lines SF 13-1 and SF 13-1a the gene etr1-1 was amplified, but these plants were sensitive to ethylene. I think the gene etr1-1 was silenced in the flowers or in the plant itself.Det generella problemet hos Campanula carpatica, är att blommorna är mycket känsliga mot etylen. Blommor som exponeras med etylen vissnar inom två till tre dagar. Behandling av plantorna med kemikalier kan förhindra problemen med etylen. Men dessa kemikalier är väldigt kostsamma och farliga för miljön. Framstegen inom den genetiska ingenjörskonsten och genförändringen med den muterade etr1-1 genen i t.ex. blåklocka och petunia har lett till plantor av Campanula carpatica sorten ‘Blue Uniform’ blivit genförändrade med genen etr1- 1 så att sorten har motståndskraft mot effekterna av etylen. Genförändringen av plantorna resulterade i genförändrade skott som odlades i vävnadskultur och planterades senare ut i växthus. Dessa olika genförändrade skott kallades för linjer och fick olika nummer. De genförändrade plantorna testades för känslighet för etylen. Totalt 20 olika transgena linjer av Campanula carpatica utvärderades. För att kunna fastställa om det fanns någon skillnad hos morfologin efter att plantorna har blivit genförändrade med ert1-1 genen gjordes morfologiska studier. För att de transformerade plantorna skulle kunna vara lämpliga för vidare växtförädling gjordes studier av blommorna och särskilt pollenet utreddes. Pollen testades för deras livsduglighet, tillväxt av pollenslangen och slutligen korsningar gjordes för att bevisa livsdugligheten. Linjerna delades upp i tre grupper beroende på den procentuella livsdugligheten eller procentuella tillväxten av pollenslangen. Grupp A inkluderar linjerna Aglo 2, Aglo 3, Aglo 4 and SF 28-1. Grupp B inkluderar linjerna SF 15-1 och ’Blue Uniform’ kontroll. Grupp C inkluderar linje SF 13-1. För att bekräfta att genen etr1-1 var insatt hos plantorna, testades plantorna också med PCR. ELISA analys utfördes för att utreda den procentuella mängden av nptII hos de genförändrade linjerna. Det slutliga resultatet visade att linjerna SF 15-1, SF 15-1c, SF 15-1de, SF 15-4 och GH 4 hade väldigt låg känslighet mot etylen. Dessa plantor hade inga morfologiska förändringar. Men linjerna Aglo 1, Aglo 2, Aglo 3, Aglo 4 och Aglo 8.3 saknade hår under blad och på stam delar. Linje SF 11-2 visade ett annat mönster hos planttillväxten då den hade ett spetsigare tillväxt beteende av knoppar och blad. Linjerna SF 15-1, SF 15-1c, SF 15-1de, SF 15-4 och GH 4 (speciellt SF 15-1) hade fertilitets värden väldigt nära kontroll plantornas. I PCR bekräftades att linjerna SF 15-1, SF 15-1c, SF 15-1de, SF 15-4, SF 13-1, SF 13-1a och GH 4 amplifierade genen ert1-1. Hos linjerna SF 13-1 och SF 13-1a genen ert1-1 var amplifierad men dessa plantor var känsliga till etylen. Jag tror att genen etr1-1 inte var aktiv i blommorna eller i hela växten

Sphinx: Monte Carlo Program for Polarised Nucleon-Nucleon Collisions

This program can be used to simulate polarised nucleon - nucleon collisions at high energies. Spins of colliding particles are taken into account. The program allows to calculate cross sections for various processes.Comment: 33pp, LaTe

Ultraclean Si/Si interface formation by surface preparation and direct bonding in ultrahigh vacuum

Silicon surfaces have been cleaned and bonded in ultra-high vacuum at a pressure in the 10-10 torr range. The bonded interfaces show extremely low contamination levels as measured by secondary ion mass spectroscopy. Nevertheless, a potential barrier could be detected at the interface spreading resistance and current vs. temperature measurements. This suggests that the barrier is caused by inevitable dislocation networks due to wafer misorientation, as well as residual oxygen at the interfac

Vertically aligned carbon based varactors

This paper gives an assessment of vertically aligned carbon based varactors and validates their potential for future applications. The varactors discussed here are nanoelectromechanical devices which are based on either vertically aligned carbon nanofibers or vertically aligned carbon nanotube arrays. A generic analytical model for parallel plate nanoelectromechanical varactors based on previous works is developed and is used to formulate a universal expression for their voltage-capacitance relation. Specific expressions for the nanofiber based and the nanotube based varactors are then derived separately from the generic model. This paper also provides a detailed review on the fabrication of carbon based varactors and pays special attention to the challenges in realizing such devices. Finally, the performance of the carbon based varactor is assessed in accordance with four criteria: the static capacitance, the tuning ratio, the quality factor, and the operating voltage. Although the reported performance is still far inferior to other varactor technologies, our prognosis which stems from the analytical model shows a promise of a high quality factor as well as a potential for high power handling for carbon based varactors

Interception and retention of wet-deposited radiocaesium and radiostrontium on a ley mixture of grass and clover

The aims of this study were to assess the potential radioactive contamination of fodder in the case of accidental radionuclide fallout, and to analyse the relationship between interception and retention of radionuclides as a function of biomass and Leaf Area Index (LAI). The interception and the retention of wet deposited 134Cs and 85Sr in ley (a mixture of grass and clover) were measured after artificial wet deposition in a field train in Uppsala (eastern central Sweden). The field trial had a randomised block design with three replicates. 134Cs and 85Sr were deposited at six different growth stages during two growing seasons (20101 and 2011) using a rainfall simulator. The biomass was sampled in the centre of each parcel 2 to 3 h after deposition and at later growth stages (1 to 5) during the growing season. The above ground biomass and LAI were measured as well. The interception of radionuclides by the ley was largest at the late growth stages; the spike and tassel/flowering (code 5:6) in the 1st year, and at flowering/initial flowering (code 6:5) in the 2nd year. There was a correlation between radionuclide interception and above ground biomass, as well with LAI, for both radionuclides in both years. The highest activity concentrations of both radionuclides were measured after deposition at the late growth stages and were found to be higher in the 2nd year. There weathering half-lives were shorter at the earlier growth stages than at the later growth stages for both radionuclides. For the magnitude of deposition chosen in our experiment, it can be concluded that the above ground biomass is a good predictor and the LAI a more uncertain predictor of the interception of radiocaesium and radiostrontium by ley grass and clover

First principle simulation package for arbitrary acousto-optic interaction in scattering materials

We present and validate a simulation package for simulating the signal generated from arbitrary acousto-optical interaction in scattering media. We further present an example on how the package can be used as a virtual lab

Fluorescence spectra provide information on the depth of fluorescent lesions in tissue

The fluorescence spectrum measured from a fluorophore in tissue is affected by the absorption and scattering properties of the tissue, as well as by the measurement geometry. We analyze this effect with Monte Carlo simulations and by measurements on phantoms. The spectral changes can be used to estimate the depth of a fluorescent lesion embedded in the tissue by measurement of the fluorescence signal in different wavelength bands. By taking the ratio between the signals at two wavelengths, we show that it is possible to determine the depth of the lesion. Simulations were performed and validated by measurements on a phantom in the wavelength range 815-930 nm. The depth of a fluorescing layer could be determined with 0.6-mm accuracy down to at least a depth of 10 mm. Monte Carlo simulations were also performed for different tissue types of various composition. The results indicate that depth estimation of a lesion should be possible with 2-3-mm accuracy, with no assumptions made about the optical properties, for a wide range of tissues