physiology and space medicine (astrobiology)
Halimeh Hassanpour
Volume 16, Issue 3 , September 2023, , Pages 69-78
Abstract
Light is a vital factor for plant cultivation. LED lamps in different spectra have some advantages such as low heat production and energy requirement, and long lifespan, which was used for the first time to design plant growth chambers in closed culture systems and space research. In this research, impact ...
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Light is a vital factor for plant cultivation. LED lamps in different spectra have some advantages such as low heat production and energy requirement, and long lifespan, which was used for the first time to design plant growth chambers in closed culture systems and space research. In this research, impact of light spectrums was studied on the growth mechanisms through chlorophyll pigments, enzyme defense system, and antioxidant metabolite analyses. Seeds were cultivated in Murashige and Skoog medium and exposed to different light spectrums of white, red, blue, and red-blue. Then, the seedlings were harvested for growth and biochemical analyses after 4 weeks. Results showed that red-blue and blue lights induced the fresh weight, dry weight, root length, adventitious roots, chlorophyll content, protein, flavonoids and antioxidant enzymes of superoxide dismutase and catalase. Blue spectrum significantly decreased stem length and increased the relative water content. Moreover, the highest amount of hydrogen peroxide was observed in seedlings treated with red light. It seems that light spectra by changing the hydrogen peroxide level can regulate antioxidant enzyme activity and enhance antioxidant metabolites, and red-blue light may use as a suitable lighting spectrum for the design of M. chamomilla cultivation chamber in space research.
physiology and space medicine (astrobiology)
Farnoush Soltani; Halimeh Hassanpour; Malek Hekmati
Volume 14, Issue 1 , March 2021, , Pages 15-22
Abstract
LED light spectrums are the proper light source for plant research in the International Space Station and the life support system. In the present study, effects of different light spectrums on some growth parameters, and antioxidant activity were investigated in Anthemis gilanica. Seedlings irrigated ...
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LED light spectrums are the proper light source for plant research in the International Space Station and the life support system. In the present study, effects of different light spectrums on some growth parameters, and antioxidant activity were investigated in Anthemis gilanica. Seedlings irrigated with 1/2 Hougland solution under different light spectrums including white, red-blue and deep red. Seedlings were harvested for physiological and biochemical analyzes after 4 weeks. Results showed the fresh and dry weight, relative water content and root length increased under the red-blue light spectrum comparing to other spectrums. Hydrogen peroxide level didn't significantly change under different light spectrums. Seedlings treated with white spectrum showed the highest DPPH scavenging activity. Also, seedlings treated with deep red spectrum showed the maximum shoot length. It seems that decrease of growth under white spectrum is related to transfer carbon and energy sources for antioxidant compound biosynthesis.
Hojat Ghassemi; Mohammad Nadafi – Pour Meibody; Keyvan Shaabani; Isa Asghari; Ebrahim Zanjirian
Volume 5, Issue 4 , January 2013, , Pages 19-28
Abstract
The application of the hydrogen peroxide as the oxidizer of a HTPB-based prototype hybrid motor is investigated in this paper. First of all, by studying the thermochemical characteristics of the propellant,operation range of different compositions is defined. A prototype hybrid motor is then designed ...
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The application of the hydrogen peroxide as the oxidizer of a HTPB-based prototype hybrid motor is investigated in this paper. First of all, by studying the thermochemical characteristics of the propellant,operation range of different compositions is defined. A prototype hybrid motor is then designed and manufactured, which is able to produce 10 kg propellant thrust. Conducting a special procedure available stabilized commercial hydrogen peroxide is processed and converted to a 90% density propellant which has less than 15 ppm tainting. A catalytic igniter is used in order to fire the motor. It was observed that the approach of employing the oxidizer to the catalyst bed is highly effective on the quality of the system performance. So, the injection quality of the oxidizer was investigated for different mass flow rates. The performance of the hybrid motor by HTTPB fuel is studied in a successful experimental test. The results of the test including the pressure and characteristic velocity are compared with the predicted theoretical simulations. Moreover, the performance specifications of the motor like the regression rate are determined and compared with the similar researches.
