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- Al-Haji, Ghazwan, 1970-
(författare)
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Road Safety Development Index : Theory, Philosophy and Practice
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation develops, presents and tests a new international tool, the so-called Road Safety Development Index (RSDI), which indicates in a comprehensive and easy way the severity of the road safety situation in a specific country and/or in comparison with other countries. There are three pillars of outcomes involved in the framework of RSDI. One pillar is the People focus (road user behaviour). The second is the System focus (safer vehicles, safer roads, enforcement, management, etc). The third is the Product focus in terms of accident death rates. This thesis analyses each of these pillars. In addition, RSDI links the key national practices of road safety to each other and to the end-results (accident death rates). The study suggests a master-list of performance indicators to be implemented for assessing road safety level in a country and for RSDI building. Based on the “master-list”, a short key list of performance indicators is chosen and classified into two primary categories that correspond to two groups of countries: LMCs “Less Motorised Countries” and HMCs “Highly Motorised Countries”. RSDI aggregates the key performance indicators into one single quantitative value (composite index). Four main objective and subjective approaches are used to calculate RSDI and determine which one is the best. One approach uses equal weights for all indicators and countries, whereas the other approaches give different weights depending on the importance of indicators. Two empirical studies were carried out, in different parts of the world, to determine the applicability of this tool in real world applications. The first empirical study comes from eight European countries (HMCs). The second empirical study comes from five Southeast Asian countries (LMCs). The RSDI results from this study indicate a remarkable difference between the selected countries even at the same level of motorisation and/or with close accident death rates. The unavailability of comparable and useful data are problems for deeper analysis of RSDI, especially the index should be as relevant as possible for different parts of the world. The empirical and theoretical assessments prove that RSDI can give a broader picture of the whole road safety situation in a country compared to the traditional models and can offer a simple and easily understandable tool to national policy makers and public.
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- Asp, Håkan, et al.
(författare)
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Anaerobic digestate as peat substitute and fertiliser in pot production of basil
- 2022
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Ingår i: Biological Agriculture & Horticulture. - : Informa UK Limited. - 0144-8765 .- 2165-0616. ; 38, s. 247-257
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Tidskriftsartikel (refereegranskat)abstract
- The common use of peat as a growing medium for plant production is questioned due to the negative effects on the environment and climate. Therefore, it is of great importance to find substitutes for peat with similar positive properties that have made peat one of the most important substrates in the horticultural sector. Production of biogas from organic residues is a valuable process, producing both energy and a residue, anaerobic digestate (AD), with a high content of plant nutrients. In this study, peat was partly substituted with AD of plant material origin up to 80% in a growing substrate for basil (Ocimum basilicum). Germination, yield and plant nutrient content were measured as well as chemical and physical properties of the growing media. The results showed that with 50% substitution of peat the growth in the AD/peat mix gave the same yield as for the fertilised peat on its own. No toxic or deficiency symptoms could be seen in the 50% mix. The important physical properties of the substrate were similar in peat and AD/peat mixes. However, the water-holding capacity was slightly decreased when part of the peat was substituted.
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- Asp, Håkan, et al.
(författare)
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Biogödsel som näringskälla vid hydroponisk odling - nitrifiering och pH
- 2020
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Ingår i: LTV-fakultetens faktablad.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Möjlighet att odla grönsaker i system som kan vara horisontella, vertikala eller i flera lager och bedrivas i källare och på tak har lett till ett ökande intresse för hydroponisk odling. I denna typ av odling tillförs växten näring genom en näringslösning som cirkulerar i systemet. I dagsläget är mycket av den hydroponiska odlingen baserad på mineralgödselmedel. Att ha möjlighet att i stället använda en recirkulerad näringskälla innebär en fördel ur miljöperspektiv. I detta faktablad beskrivs hur en recirkulerad näringskälla, biogödsel, ska hanteras för att fungera som näringslösning i hydroponisk odling.
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- Asp, Håkan, et al.
(författare)
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Circularity in practice: reusing restaurant waste for in-house vegetable production
- 2021
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 281-286
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Konferensbidrag (refereegranskat)abstract
- Production of biogas is a common way to handle organic waste products and it provides not only energy but also an anaerobic digestate (AD) rich in plant nutrients. In order to create a close loop between food consumption and vegetable production this project was undertaken to see if food waste from a restaurant, could be used to produce a liquid fertilizer for lettuce production to the same restaurant. Growth experiments in a hydroponic set up were made with nitrified AD. The AD was tested as a hydroponic fertilizer at two dilution levels. In one trial the solution was also amended with mineral nutrients and all the trials were compared to a mineral nutrient control. Results indicate that it is possible to use the digestate as a fertilizer for lettuce, and that amendment with certain mineral nutrients enhances the growth. Plant concentrations of Na and Cl indicates that there might be a problem with toxicity but it was not clarified by these experiments.
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- Asp, Håkan, et al.
(författare)
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Development and Acclimatisation of Horticultural Plants Subjected to Narrow-Band Lighting
- 2014
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Ingår i: European Journal of Horticultural Science. - 1611-4426 .- 1611-4434. ; 79, s. 45-51
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Tidskriftsartikel (refereegranskat)abstract
- Light-emitting diodes (LED) allow narrow-band light to be easily obtained and can be used for narrow-band lighting in plant cultivation, with possible effects on plant growth and development. This study examined use of narrow-band lighting of different wavelengths in the cultivation of ornamental pot plant (Pelargonium and Petunia), tomato (Solanum lycopersicum) transplants and sunflower (Helianthus annuus), either as sole light source in growth chambers, or as end-of-day (EOD) treatment in a greenhouse environment. Biometric measurements on plant growth and measurements of photosynthesis and stomatal conductance showed that when Helianthus was grown exclusively in blue light, stem elongation was greater than when it was grown exclusively in yellow, red, green or white light. Similar results were obtained when blue light was supplied in EOD treatments for Petunia and Pelargonium and for tomato. However, stem elongation was also high when red light was given as EOD treatment to tomato, whereas green light gave the least elongated plants in these conditions. Biomass production was generally not affected by the different EOD treatments. For Helianthus plants grown solely in monochromatic light, plant biomass production was highest in red light. For Pelargonium, photosynthetic rate was highest in blue light. It was conduded that plant response to different wavelengths is species-dependent and that EOD treatment with narrow-band lighting might be useful for plant growth regulation.
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- Asp, Håkan, et al.
(författare)
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Nutrient utilization and growth of tomato crops fertilized with solid anaerobic digestate
- 2024
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Ingår i: Scientia Horticulturae. - 0304-4238 .- 1879-1018. ; 329
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestate is a valuable resource for horticultural production, as it contains nutrients and fibers that can be used in plant growing medium. However, compared with hydroponic production based on mineral fertilizers, obtaining accurate nutrient supply at each stage of the growth cycle may be challenging. In an experiment using container-grown tomato crops, we evaluated different fertilization regimes with solid anaerobic digestate (SAD). Four different treatments were compared, two involving different proportions (19 % and 37 % by volume) of SADs in the peat-based growing medium, one treatment where growing medium with 37 % SAD was inoculated with active nitrifying bacteria, and one treatment where 15 % (v/v) of the peat in growing medium with 37 % SAD was replaced with sawdust to control nitrogen (N) availability during cultivation. A mineral-fertilized treatment (N-P-K 5–1-5) with approximately similar N amount as in the treatment with 37 % SAD was used as reference. Nutrient availability, nutrient uptake efficiency, crop performance (plant growth, biomass accumulation), and plant stress (chlorophyll fluorescence) were monitored during cultivation. The concentration of ammonium was initially high (190–416 mg/L substrate) in the growing media fertilized with anaerobic digestate, while the concentration of nitrate was low. Readily available ammonium concentration decreased rapidly during cultivation, to around 50 % after 10 days and to almost 100 % by the end of the cultivation. Available nitrate concentration was initially low (0–8 mg/L in the different treatments) and decreased to zero within a week, but increased slightly from day 40 of cultivation. Nutrient use efficiency was generally higher (15–50 % for different nutrients) in the treatment with 19 % digestate. Inclusion of sawdust in the growing medium decreased nutrient use efficiency by 30–50 %. Compared with the mineral-fertilizer reference, biomass production was lower in all treatments fertilized with digestate, with 37 % and 19 % SAD resulting in 62 % and 47 % of total biomass obtained in the reference, and similar reductions in yield of harvestable fruits. Chlorophyll fluorescence measurements indicated elevated plant stress in the treatments fertilized with SAD. Addition of sawdust or nitrifying bacteria did not help to control nitrogen availability during cultivation. Therefore, anaerobic digestate fertilizers need further optimization before they can be a competitive alternative to mineral fertilizers.
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