| 1. |
- Ahlborg, Helene, 1980, et al.
(författare)
-
A background on social context and renewable energy sources in Mozambique and Tanzania - An initial report from the STEEP-RES project
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This initial research report, appearing before the formal commencement of the STEEP-RESproject, focuses on the background and context of the project which is intended to make asocio-technical-ecological assessment of prerequisites to and effects of introducing renewableenergy sources (RES) into rural communities of the coastal Tanzania and Mozambique. Thereforea short review of the scientific literature is made dealing with societal prerequisites andrepercussions of electrification. Technical aspects related to the availability of natural resourcesand technologies for renewable energy resources utilisation are also briefly coveredalong with some very brief remarks on possible environmental repercussions.The review of the social context covers > 45 papers dealing with different experiencesof electrification in developing countries relating to renewable energy applicable for povertyalleviation in rural settings. The primary energy sources in rural East Africa are biofuels andelectricity plays a limited role. Electrification influences the composition of the energy mix,but during early development it has very limited impact on the use of wood for cocking andheating purposes. The institutional and financial frameworks are currently major barriers tosmall-scale RES-projects, although local technical and financial capacities are slowly increasing.Social and cultural settings create important drivers and barriers to introduction and diffusionof new technologies. Further, poverty and gender inequality are considered key issues forelectrification projects and create important barriers to success. Participatory and needorientedapproaches are considered necessary by most researchers for successful RES-projects.The more technical review is based on ~50 papers covers the existing renewable energysources (RES) - biofuels, solar, hydro, geothermal, wind, wave and tide. The technologicalstate and resource abundance of each source is discussed briefly in a regional context,along with environmental considerations on each technology.As large scale hydropower is being used in the region since long, it is noticeable thatsmall- and micro-scale hydropower is now advancing and will contribute to electrification inmany smaller river-bound areas. Bioenergy, in terms of firewood is widely used for cookingpurposes, although not environmentally sustainable and not with potential for electricity generation.Biofuels from plantations is rapidly increasing in Africa as well as the global trend.Also here, environmental considerations are of great importance for sustainability. Other RESof potential in the region, and with perhaps less environmental constrains, may be solar photovoltaicand tidal energy. Of less importance, according to regionally sparse resource abuniidance, seem to be wind and wave energy. The potential of geothermal energy is geographicallyrestricted to a few good locations.An inventory of actors within the field of East-African RES based on internet resourcesreveals a “top-heavy” information situation with many and well-designed information sourcesand active networks on global and African regional level while less web-information is availablefrom local levels in Tanzania and Mozambique, where only few companies working inthe field has been identified. More direct investigations are needed starting from the actorsidentified in this initial inventory.
|
|
| 2. |
|
|
| 3. |
- Molander, Sverker, 1957, et al.
(författare)
-
Socio-technical-ecological evaluations of the potential to implement renewable energy sources in coastal areas of tropical developing countries – an East African case study
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The suggested project aims at evaluating the potential for a successful implementation of renewableenergy sources in the coastal zone of tropical developing countries integrating results from differentscientific disciplines (ecology, social science and technology) into a useful support for developmentpolicy. Its emphasis will be on remote areas where poor infrastructures raise the demand forindependent electricity supplies. Moreover, the project intends to identify key-issues and sociotechnicalpathways for a future integration of suitable renewable energy sources in such areas.The research will be based on analyses of the relationships between technical, ecological andsocial systems and focus on applying adequate technology in a socially and ecologically feasible way.The energy sources considered will be selected from local natural flowing resources, i.e. mainly tidal,stream, and wave energies.With funding from Sida (SAREC Planning Grant) and Adlerbertska Forskningsstiftelsen, a planningstudy was carried out during October – November 2007, including the subsequent parts:1) meetings with representatives from several concerned institutions in Mozambique and inTanzania2) field visit to remote rural areas in southern Tanzania where hydrographical and coastmorphological features were documented3) meetings with village representatives in remote rural southern Tanzania in order to collectinformation about living standards, energy demands and development intentionsCompiled results from the three parts are presented in this report and will constitute a baseline for theforthcoming application of Sida Project grant, to be handed in April 2008. When taking part of theresults it is important to keep in mind that the suggested project does not intend to construct any actualpower plants, or pilot plants, but to study the prerequisites and consequences, technical, natural as wellas societal in order to evaluate if and how a future implementation of these recent technologies couldbe carried out in a feasible and sustainable way.This report is written with a plain perspective and contains no abstract. As the proceedings of the studywill be the basis for a research application in progress, conclusions will instead be developed withinthat context.
|
|
| 4. |
|
|
| 5. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
Environmental Impact of Titanium Dioxide Nanoparticles – Applying Life Cycle Thinking and Risk Assessment for Swedish Conditions
- 2008
-
Ingår i: 3rd International Conference on the Environmental Effects of Nanoparticles and Nanomaterials, Birmingham University, Birmingham, UK, September 15-16, 2008.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The risks of nanoparticles have been issued by several different groups, e.g. The Royal Society (2004) and Friends of the Earth (2006), and the concept nanotoxicology has been introduced to underline the distinctive toxicological features of nanoparticles (Oberdörster et al. 2005). Some nanoparticles, such as carbon nanotubes, have been outlined as hazardous and great caution has been suggested before introducing carbon nanotubes into the market (Poland et al. 2008). According to a risk assessment performed by Mueller and Nowack (2007), titanium dioxide nanoparticles had higher predicted environmental concentration compared with the predicted no effect concentration than both silver nanoparticles and carbon nanotubes, and further detailed studies regarding titanium dioxide nanoparticles were suggested. However, no sensitivity analysis was performed in Mueller and Nowack (2007), and a crude model was used to model environmental faith of the titanium dioxide nanoparticles. Our study applied substance flow analysis in order to facilitate a comprehensive environmental risk assessment of titanium dioxide nanoparticles (see e.g. Tsunemi and Wada (2008) and Fuster et al. (2002)). A detailed investigation of the production of titanium dioxide nanoparticles and their application in society was performed facilitating hazard identification according to Hansen et al. (2007). Emissions were calculated based on use assumptions and a modelling of the environmental faith of the titanium dioxide nanoparticles was attempted including the particle aggregation and interaction with natural organic substances that modify bioavailability. Predicted environmental concentrations were calculated and compared with predicted no effect concentrations according to several ecotoxicological studies and in order to assess the uncertainty a sensitivity analysis was performed for input parameters.
|
|
| 6. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
Fate modeling of titanium dioxide nanoparticles in the water compartment by colloid chemistry
- 2009
-
Ingår i: 1st International Conference on the Environmental Implications and Applications of Nanotechnology, June 9-11, 2009, Amherst, U.S.A..
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Titanium dioxide is one of the most produced nanoparticles according to the Project of Emerging Nanotechnologies (www.nanotechproject.org). According to Mueller and Nowack (2008) it is also the nanoparticle that has the largest environmental concentration in the Swiss water compartment, 16 µg/l according to their high estimate. Further, Boxall et al. (2007) estimate a titanium dioxide nanoparticle environmental concentration of 24.5 µg/l in the UK water compartment for a scenario that probably overestimates the current exposure levels. However, neither of these risk models take fate processes such as aggregation and sedimentation into account. Colloid chemistry deals with particles within the size range of 1 nm to 1 µm. Nanoparticles of a size between one nanometer and a few hundred nanometers are thus well within the colloid range. Theories of colloid chemistry suggest that sedimentation of nanoparticles depends mainly on the density and the viscosity of the water and the density and size of the particles. Sedimentation is shown not to be an important factor, since the sedimentation of particles smaller than ~300 nm is negligible. Aggregation is a more complex process which depends on factors such as temperature, salinity, ion valence, pH, point of zero charge, the Hamaker constant, particle size and particle concentration (Elimelech et al. 1995). These factors were estimated for a typical Swedish lake and calculations were performed in MATLAB. The aggregation is modeled by kinetics according to Smoluchowski (1917) but adjusted according to the DLVO theory (see Elimelech et al. 1995). Preliminary results show that aggregation can reduce the predicted environmental concentration significantly in a short time. It would take less than 4 minutes for the initial environmental concentrations predicted by both Mueller and Nowack (2008) and Boxall et al. (2007) to be reduced by 50%. After 24 hours, both predicted environmental concentrations would have fallen below 0.1 µg/l.
|
|
| 7. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
MODELLING ENVIRONMENTAL FATE OF TiO2 NANOPARTICLES IN WATER – IMPLICATIONS FOR EMPIRICAL VALIDATION STUDIES
- 2009
-
Ingår i: 4th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials, 6-9 September, Vienna, Austria.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The potential environmental effects of nanoparticles (NPs) require interdisciplinary research to assess the risks. One part of a risk assessment concerns exposure, which builds on knowledge of the environmental fate. In this particular case the fate of TiO2 NPs in the water compartment was modelled by applying a second order kinetic rate equation and the DLVO theory. Assumptions were made regarding water parameters such as pH, salt concentration and temperature, as well as regarding particle properties such as Hamaker constant, primary particle size and point of zero charge. The effect of sedimentation was taken into account, but as one would expect the influence of sedimentation on such small particles is very small. The model was implemented in MATLAB®. Results indicate the importance of agglomeration as an important fate mechanism, and that pH andpoint of zero charge are important parameters with regards to agglomeration. Other parameters such as the Hamaker constant, salt concentration and temperature were shown not to have a significant effect, which is in goodcorrelation with empirical studies. Also, we would like to see our model validated by empirical studies. Important implications then are to include a continuous inflowof NPs in the experimental setup and to work at environmentally relevant water properties. For example is the effect of natural organic matter (NOM) on theagglomeration not modelled, despite that its significance has been pointed out in many studies. This is due to a weak link between mathematical expressions andempirical data for this particular part of the model. It is of importance that this linkage is strengthened both by theoretical and empirical studies on NOM aimingat producing mathematical expressions, and empirical data, that can assist fate modelling of NPs.
|
|
| 8. |
- Arvidsson, Rickard, 1984, et al.
(författare)
-
The fate of titanium dioxide nanoparticles in the water compartment
- 2009
-
Ingår i: SETAC Europe 19th Annual Meeting, 31 May-4 June, 2009, Göteborg, Sweden.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Environmental risk of nanoparticles has been assessed in several studies. Titanium dioxide has been identified as one of the potentially most problematic nanoparticles. It has been shown that a large amount of the titanium dioxide nanoparticles may end up in the water compartment. These risk assessments constitute first estimates and several fate mechanisms are not taken into account. In this study, we propose a risk model that includes the two fate mechanisms sedimentation and aggregation. The sedimentation rate of titanium dioxide nanoparticles is determined using simple laws of motion. Still water is assumed, which gives optimal conditions for sedimentation. It is shown that despite the optimal conditions for sedimentation, the sedimentation rates of particles with a diameter of 100 nm and 1000 nm are about 8 years and 1 month, respectively. One month can be regarded as a long time from a risk perspective, and thus sedimentation is shown not to be an important factor for the removal of titanium dioxide nanoparticles from the water compartment. However, preliminary results show that aggregation can reduce the predicted environmental concentration significantly in a short time. Hence, equilibrium concentrations could be several orders of magnitude lower than what has been indicated in earlier studies. The aggregation of titanium dioxide nanoparticles is modeled using Smoluchowski kinetics and the DLVO theory, which are commonly used in colloid chemistry. The aggregation is shown to depend mainly on the pH of the water compartment and the zero point charge of the particles.
|
|
| 9. |
- Börjeson, Fia Christina, et al.
(författare)
-
Ger koppling av kunskapsinlärning och färdighetsövning ökad djupinlärning? : "Utveckling av kursmoment i ”Miljö- och resursanalys för hållbar utveckling V2”
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Kursen ”Miljö- och resursanalys för hållbar utveckling V2”, som är en av de obli-gatoriska kurserna under andra året i civilingenjörsutbildningen (Väg och Vat-ten) vid Chalmers tekniska högskola har omfattats av ett pedagogiskt utveck-lingsarbete. Utgångspunkten till de förändringar som prövats har varit grundade i och inspirerade av Experiential Learning Theory1. Lärarlaget utvecklade, med stöd av en gemensamt producerad begreppsmodell, metoder för att intervenera på olika stadier, och på olika sätt, i studenternas lärprocess. Arbetet har handlat om att skapa goda förutsättningar för att förstärka studenternas lärande. Ett så-dant lärande innebär att studenterna tillägnar sig en ökad förståelse och fördju-pade kunskaper, genom att koppla samman färdigheter som reflektion och kommunikation med tillägnandet av ett relativt abstrakt stoff (miljö- och resurs-analys). Detta har skett med hjälp av att modifiera kursens organisation och struktur, genom att utveckla återkommande och varierande typer av reflektions-övningar samt genom att arbeta fram återkommande och varierande former för olika typer av återkoppling till studenterna. En viktig del av arbetet har också va-rit att försöka utvärdera utfallet av de förändringar som genomförts i kursen. Ut-ifrån de begränsningar som det empiriska materialet innebär är det inte helt klart om titelns fråga besvarats i undersökningen, men studenternas resultat liksom deras utvärdering av kursen pekar tydligt på positiva effekter ifråga om lärandet.
|
|
| 10. |
|
|
