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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The responses of ectohydric and endohydric mosses under ambient and enhanced ultraviolet radiation

Lappalainen, N. (Niina) 08 June 2010 (has links)
Abstract Previous reports on the effects of enhanced UV-B radiation on bryophytes have been equivocal. This study shows that mosses not only respond to enhanced UV-B, but they are affected by changes in ambient radiation. The studies were conducted with two model species common in northern environments; red-stemmed feather moss (Pleurozium schreberi) and juniper haircap moss (Polytrichum juniperinum). Both species showed high concentrations of methanol-extractable UV-absorbing compounds (UACs) with high spring-time and early-summer UV, whereas in P. juniperinum, the concentration was affected by early-summer drought. The UACs of P. juniperinum increased again towards autumn suggesting a role in winter hardening. The (spring-time) cell wall-bound UV screen was important to both species. The fundamental adaptation of P. juniperinum to open and exposed environments was reflected in relatively higher concentrations of total UACs compared to P. schreberi. The enhanced UV-B experiments in situ were conducted over two years in Oulu and six years at the FUVIRC site in Sodankylä. Some of the effects of UV-B were seen within the first years of the experiments, or even within hours, while others were observed after several years. Five or six years of enhanced UV-B treatment increased the methanol-extractable UACs of P. schreberi and decreased the green shoot growth of P. juniperinum. The immediate light environment was proposed to have an impact on the varying UAC concentrations. Some mitigating effects of UV-A were observed as well. Off-site measured, reconstructed and modelled UV radiation data was used for comparisons of light environment in situ, or when performing a reconstructive research with historical samples. The environmental sample banks can provide a useful tool to study past environmental conditions, and even reconstruct past radiation levels. It was shown in this study that UACs in P. schreberi and P. juniperinum have fundamental roles as UV-B screens in the cell walls, but there is also a variable response with the soluble fraction that reacts and adapts to the changes in UV radiation. The responses to increasing UV-B radiation vary in magnitude and in time. As P. schreberi and P. juniperinum possess circumboreal and cosmopolitan distributions, the effects of UV-B on these species and consequently on ecosystems has a broad application.
2

Green Room : A climate controlling grow-box for growing mushrooms and greens. / Green Room : En klimatkontrollerande tillväxtlåda för odling av svampar och växter.

Skullman, Bill, Herlin, Gabriella January 2023 (has links)
This report covers a project on a partially automated aeroponic and fungi growing system. The purpose is to evaluate if an enclosed space system can be automated to produce healthy crops of greens and fungi, and investigate how well the system can switch between these two growth modes. Factors that will be automated include regulation of temperature, humidity, air ventilation, and light exposure time. The research will be focused on Romaine lettuce and Golden Oyster mushroom. The methods used include research, hardware setup, software programming, chassis construction, and experiments. Relevant factors for the growing environment, such as lighting, temperature, and nutrient solutions were studied. The hardware components used in the project can shortly be described as follows. A real time clock ensure accurate timing for the microcontroller that regulates the indoor climate based on sensor readings. LEDs light up the chamber and a humidifier provide the roots access to a nutrient solution. A fan provides cooling, and filters block out unwanted microorganisms and fungi spores from the ventilation air. A display provides the user with relevant information. The system code written in C++ contain six main functions and two support functions. Depending on the growth mode, climate control functions are selected. The system has control variables allowing the administrator to set threshold levels for humidity and nutrient spray periods. The outer case of the chassis was made out of painted acrylic to block out light and retain moisture. The water-nutrient solution basin was designed to avoid leakage, net cups hold the plants in a raised bed, a base plate acts as flooring for the mushrooms, as well as a placement enforcer for the humidifier. An inner roof separates the moist growth chamber from the electronics compartment above. Two experiments were conducted in separate prototypes simultaneously for green sand mushrooms. For the mushroom experiment, a grow kit was installed after thorough cleaning. The fruiting process was monitored and photographed daily. Results showed successful mushroom growth and healthy fruiting bodies. For the greens experiment, a nutrient solution was mixed and lettuce seeds were placed in rock wool cylinders that were installed in net cups. Photographs were taken every three days to track the progress. The lettuce seeds germinated and started growing. Control variables were altered multiple times to maximize performance but optimal settings were not found. The plants died whilst unsupervised. The experiments were partially successful and demonstrated potential for growing both greens and mushrooms. The prototype was effective in maintaining set temperature and humidity levels. The parameters necessary for successful growth was effectively automated and the system has great potential for further improvements and automation. / Målet med projektet är att studera hur väl det går att odla både svamp och fotosyntetiserande växter i samma slutna, delvis automatiserande aeroponiskasystem. I projektet undersöks om det går att byta mellan de två odlingssätten och hur automatiserad processen kan vara. Produkten är tänkt att fylla utrymmet som hittats på marknaden för enkla odlingssystem hemma för i synnerhet svamp. Faktorer att ta hänsyn till är temperatur, luftfuktighet och ljusexponeringstid. Andra faktorer som pH värde eller byte av vattnet utesluts till följd av tid- och resursbegränsningar. Metoden är indelad i forskning, hårdvara, mjukvara, chassi och experiment. Forskningen täcker nödvändig information om faktorer relaterade till odling av både svamp och gröna växter i aeroponiska system. Exempelvis hur mycket ljus, vatten och näring som behövs. Kapitlet om hårdvara tar upp vilka komponenter som används och varför. I centrum är en microkontroller, en Arduino micro, som med hjälp av en realtidskolocka styr när belysningen ska lysa, när luftfuktaren ska vara på samt när fläktarna ska gå. En DHT11 sensor skickar information till Arduinon att agera utifrån. I mjukvara ingår hur koden är uppbyggd för att styra microkontrollern och hur användaren kan anpassa värden till sitt tycke. För att hjälpa användaren visas relevant data på en skärm. Produkten är uppbyggd med ett mörklagt och tätande skal av akrylplast. Vatten med eventuell näring för växtläget är samlat i en tät balja längst ner i lådan där luftfuktaren även är placerad. Över baljan vilar antingen ett svampodlingskit på en perforerad yta eller en hållare för odling av växter i nätkorgar med stenull. I taket är en 20W LED fäst på en kylfläns för kylning tillsamman med en närliggande fläkt. Allra högst upp är elektroniken, skyddad från fukten nere i lådan av ett lager akrylplast.Två experiment hölls parallellt med varandra i två likadana odlingskammare för att hinna utvärdera både svamp och fotosyntetiserande växter. Citronmussling valdes som svamp och Romansallad som växt. Experimenten dokumenterades regelbundet med fotografier och kommentarer om det som observerats. Experimenten var till stor del lyckade även om vissa parametrar behövde justeras under förloppet. Det aeroponiska systemet producerar svamp och växter av god kvalitet. Slutsatsen som kan dras är att det går att odla både svamp och växter i samma produkt. De parametrar som inkluderats inom projektets avgränsningar gick att automatisera. Det finns även goda möjligheter att förbättra automatiseringsnivån.

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