Enkätundersökning om Borås Stads skolskogar

As a thesis, I have conducted a survey in collaboration with the technical administration Borås city, which deals with examining elementary schools and preschools use of school forests. And look at how it can develop in the future to better match the educational activities. The survey was done because I am interested in the more social values that a forest can embarrass and highlight the importance of staying out in the forest. It is important to work for children and young people to have good opportunities to have school to some extent outside. These answers showed surprisingly big differences between primary and lower secondary school and use school forests. From the majority of respondents, many wanted more information and help to develop the use of school forests. The survey also demonstrated a great interest from schools for these issues. Surveys provide answers to the different requirements that elementary schools and preschools have in the school forests and provide opportunities for improvement of the forest forests, both in Borås city and in a broader perspective. Specifically, it provides answers to which schools want help with the creation and development of school forests. It shows the differences in the use and requirements between primary and lower secondary schools and preschools. This provides a good basis for well-adapted school forests for each activity. One big question is how to make it even more accessible for schools to use school forests in everyday life. One word is that it must be easy to use

Vertical nanowire TFETs with channel diameter down to 10 nm and point S MIN of 35 mV/decade

We present experimental data from vertical InAs/InGaAsSb/GaSb nanowire tunnel field-effect transistors with channel diameter scaled down to 10 nm and ability to reach a point subthreshold swing of 35 mV/decade at VDS = 0.05 V. Furthermore, the impact of drain, channel and source diameter scaling on the subthreshold swing and currents are studied. Impact of gate-overlap is more evident for devices with highly scaled source due to strong reduction of the current. Furthermore, small channel diameter makes these devices more susceptible to Random Telegraph Signal noise

Fysikaliskt verkande växtskyddsmedel

Physically active pesticides, such as mineral oils, vegetable oils and soaps, have been used by integrated and organic fruit and berry growers in recent years. The use will most probably increase, as one of several future tools to replace and complete some of the chemical pesti-cides. Physically active pesticides can be effective only if they contact pests thoroughly, un-derlining the importance of high quality application technologies. The objectives of the project are, based on applied research, to produce knowledge of physical active pesticides and of suitable application technology for these, within fruit and berry pro-duction. The effect on the beneficial fauna should be studied as well. Series of experiments were carried out; evaluation of pesticide efficacy in field experiments, determination of application rates, laboratory studies, survey of fauna population, construction of sprayers etc. Variables investigated were dosage, concentration, application rate, and appli-cation method. Most field experiments were conducted at commercial farms. One study shows that a stabile oil spray liquid, without tendencies to separation, was obtained by premixing oil and soap (emulsifier) at a 1:1 ratio. Oil spray was applied to control rasp-berry beetle (Byturus tomentosus) in a field experiment. In general, efficacy results were promising, although dosage and application rate were not correlated. The effect on beneficial fauna was not significant while a small difference was noted between treated and control plots. Apple coddling moth (Cydia pomonella) was treated in a pilot study (without replica-tion), showing a limited reduction of the pest. Several evaluations of spray liquid penetration into canopies were made in strawberry, rasp-berry and apple. A fluorescent tracer was added to the spray liquid to quantify deposits. The application quality on sprayed leaves were analysed and visually graded with UV-light. Test results indicated that spray deposit was insufficient at the lower leaf surfaces in the canopy centres, despite of efforts with locating nozzle at different positions, using crop tilters, or in some case using the air assistance. The best deposition result was achieved in apple canopies, probably because air assistance already was used as a standard procedure. Research reports, completed by field and laboratory studies, show that physical active pesti-cides have effects on pests. The effect is however limited, compared to traditional chemical pesticides. This implies a number of high demands within different disciplines; demands that have to be fulfilled to achieve the sufficient effect. Action should only be made against insects with sensitive stages in their life cycle, and they have to be exposed enough to be targeted by the spray liquid. This requires increased knowledge on behaviours of pests, further developed prognosis/warning systems, and, eventually, repeated spraying with sophisticated application methods. Importantly, further research is needed, including completing plant protection ac-tions with different mechanisms, as pheromones, support of beneficial fauna and other pre-cautious contributions

Changes in winter length and spring flood in a boreal forest in northern Sweden

Jordens klimat förändras, atmosfären och haven blir allt varmare. Dessa förändringar påverkar vattenbalansen. Kandidatarbetes syfte har varit att undersöka huruvida det skett förändringar i vinterns längd och basflöde samt vårflodens tidpunkt, högsta flöde och volym i Krycklans försökspark under perioden 1981-2015. Daglig vattenflödesdata från Krycklans Site 7 laddades ned från Krycklans öppna databas. Snödata användes för att kunna definiera vinterns början. För att upptäcka eventuella trender i datat utfördes en regressionsanalys och ett Mann-Kendall test. Resultatet från regressionsanalysen och Mann-Kendall testet visade på en signifikant trend mot kortare vintrar, lägre högsta flöde och att vårfloden startar tidigare. Ingen av analyserna visade på någon signifikant förändring i vårflodens volym, vinterns basflöde och tidpunkt för högsta flöde. Vinterns basflöde visade inte på någon förändring vilket skulle kunna bero på definitionen av vinter som användes. Studiens definition av vinter var tiden mellan snön har lagt sig till vårflodens början. Vinterbasflödet var det dagliga flödets medelvärde under vintern. Genom att studera tiden på vintern då flödet är som lägst skulle eventuellt en förändring av vinterbasflödet upptäckas. Den relativt korta period mellan 1981-2015 som studerats här kanske inte är tillräcklig för att upptäcka förändringar i ett Svenskt klimat på lång sikt.The Earth’s climate is changing, the atmosphere and oceans are getting warmer. These changes affect the water balance. The aim of this thesis have been to investigate whether there has been any changes in winter length and winter base flow as well as in spring flood timing, maximum flow and volume in the The Krycklan catchment study area during the period of 1981-2015. Daily water flow data from Site 7 in Krycklan was downloaded from Krycklans open database. Snow data was downloaded to help define the start of winter. A regression analysis and a Mann- Kendall test was performed to reveal any trends in investigated parameters. The results from the regression analysis and Mann-Kendall test showed a significant change towards shorter winters, lower maximum flows and earlier spring flood onset. There was no significant change in spring flood volume, winter base flow or timing of maximum flow in any of the statistical analysis. The winter base flow did not show any trend which might be due to the definition of winter that was used. In this study winter is defined as the time between snow arrival and spring flood onset. The winter base flow was defined as the average daily flow during the winter. A trend might been detected by only studying the time during winter where the base flow is at its lowest. The relatively short period 1981-2015 that was used in this study might not be a long enough time scale to show long term changes in a Swedish climate

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

Carbon nanotube based bolometer

The contacts of single carbon nanotubes and bundles of carbon nanotubes with superconducting and metallic electrodes are investigated in order to create bolometers and electron coolers. Tunneling contacts of the carbon nanotubes with aluminum electrodes are obtained. The current-voltage characteristics of junctions are analyzed for temperatures from room temperature to 300 mK. The resistance of individual nanotubes is primarily determined by defects and is too large for applications. The use of the bundles of carbon nanotubes makes it possible to considerably reduce the resistance of the bolometer, which is determined by a small number of conducting tubes with good tunneling contacts with the electrodes. The energy gap is equal to hundreds and tens of millivolt in the former and latter cases, respectively. Structures containing bundles of carbon nanotubes can be described in a model with a Schottky barrier. The samples with bundles of carbon nanotubes exhibit the bolometric response to external high-frequency radiation at a frequency of 110 GHz with an amplitude up to 100 μV and a temperature voltage response to 0.4 mV/K

Diameter-Dependent Photocurrent in InAsSb Nanowire Infrared Photodetectors.

Photoconductors using vertical arrays of InAs/InAs1-xSbx nanowires with varying Sb composition x have been fabricated and characterized. The spectrally resolved photocurrents are strongly diameter dependent with peaks, which are red-shifted with diameter, appearing for thicker wires. Results from numerical simulations are in good agreement with the experimental data and reveal that the peaks are due to resonant modes that enhance the coupling of light into the wires. Through proper selection of wire diameter, the absorptance can be increased by more than 1 order of magnitude at a specific wavelength compared to a thin planar film with the same amount of material. A maximum 20% cutoff wavelength of 5.7 μm is obtained at 5 K for a wire diameter of 717 nm at a Sb content of x = 0.62, but simulations predict that detection at longer wavelengths can be achieved by increasing the diameter. Furthermore, photodetection in InAsSb nanowire arrays integrated on Si substrates is also demonstrated

Scaling of Vertical InAs–GaSb Nanowire Tunneling Field-Effect Transistors on Si

We demonstrate improved performance due to enhanced electrostatic control achieved by diameter scaling and gate placement in vertical InAs-GaSb tunneling field-effect transistors integrated on Si substrates. The best subthreshold swing, 68 mV/decade at VDS=0.3 V, was achieved for a device with 20-nm InAs diamter. The on-current for the same device was 35 µA/µm at VGS=0.5 V and VDS=0.5 V. The fabrication technique used allows downscaling of the InAs diameter down to 11 nm with a flexible gate placement

From spin chains to real-time thermal field theory using tensor networks

One of the most interesting directions in theoretical high-energy and condensed-matter physics is understanding dynamical properties of collective states of quantum field theories. The most elementary tool in this quest is retarded equilibrium correlators governing the linear response theory. In this article we examine tensor networks as a way of determining them in a fully ab initio way in a class of (1+1)-dimensional quantum field theories arising as infrared descriptions of quantum Ising chains. We show that, complemented with signal analysis using the Prony method, tensor network calculations for intermediate times provide a powerful way to explore the structure of singularities of the correlator in the complex frequency plane and to make predictions about the thermal response to perturbations in a class of nonintegrable interacting quantum field theories