| 1. |
- Olsson, P., et al.
(författare)
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Uptake, toxicity and radiation effects of the boron compounds DAAC-1 and DAC-1 in cultured human glioma cells
- 1998
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Ingår i: International Journal of Radiation Biology. - 0955-3002 .- 1362-3095. ; 73:1, s. 103-112
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study the uptake, toxicity and radiation effects in vitro of a diol-amino acid-carborane (DAAC-1) and make comparisons with the previously studied diol-amine-carborane (DAC-1). MATERIALS AND METHODS: Toxicity and radiation effects were studied with clonogenic survival, uptake by measuring the cellular boron content and the subcellular distribution was investigated after organelle separation with centrifugation. The studied cell line was human glioma U343. RESULTS: DAAC-1 showed an accumulation of 1-1.5 times, compared with the culture medium, and was non-toxic up to 47 microg boron/ml. The accumulation of DAC-1 was about 90 times, but toxic effects were detectable already at the concentration 5 microg boron/ml. None of the compounds was localized in the cell nucleus. Following irradiation with thermal neutrons, DAC-1 was about 2.5 times more effective than DAAC-1 and about 4.9 times more effective than neutrons alone, at the survival level 0.2. The dose modifying factors, when compared with the neutron beam alone, were for both DAAC-1 and DAC-1 about 1.5 and about 5 when compared with 60Co-gamma-radiation. CONCLUSIONS: DAAC-1 was less toxic than DAC-1 but gave less accumulation of boron. Both substances gave significant boron-dependent cell inactivation when the test cells were exposed to thermal neutrons.
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| 7. |
- Ruiz-Puerta, Emily J., et al.
(författare)
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Holocene deglaciation drove rapid genetic diversification of Atlantic walrus
- 2023
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - 1471-2954. ; 290:2007, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Rapid global warming is severely impacting Arctic ecosystems and is predicted to transform the abundance, distribution and genetic diversity of Arctic species, though these linkages are poorly understood. We address this gap in knowledge using palaeogenomics to examine how earlier periods of global warming influenced the genetic diversity of Atlantic walrus (Odobenus rosmarus rosmarus), a species closely associated with sea ice and shallow-water habitats. We analysed 82 ancient and historical Atlantic walrus mitochondrial genomes (mitogenomes), including now-extinct populations in Iceland and the Canadian Maritimes, to reconstruct the Atlantic walrus’ response to Arctic deglaciation. Our results demonstrate that the phylogeography and genetic diversity of Atlantic walrus populations was initially shaped by the Last Glacial Maximum (LGM), surviving in distinct glacial refugia, and subsequently expanding rapidly in multiple migration waves during the late Pleistocene and early Holocene. The timing of diversification and establishment of distinct populations corresponds closely with the chronology of the glacial retreat, pointing to a strong link between walrus phylogeography and sea ice. Our results indicate that accelerated ice loss in the modern Arctic may trigger further dispersal events, likely increasing the connectivity of northern stocks while isolating more southerly stocks putatively caught in small pockets of suitable habitat.
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| 10. |
- Sharma, Sapna, et al.
(författare)
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Long-term ice phenology records spanning up to 578 years for 78 lakes around the Northern Hemisphere
- 2022
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Ingår i: Scientific Data. - : Springer Nature. - 2052-4463. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- In recent decades, lakes have experienced unprecedented ice loss with widespread ramifications for winter ecological processes. The rapid loss of ice, resurgence of winter biology, and proliferation of remote sensing technologies, presents a unique opportunity to integrate disciplines to further understand the broad spatial and temporal patterns in ice loss and its consequences. Here, we summarize ice phenology records for 78 lakes in 12 countries across North America, Europe, and Asia to permit the inclusion and harmonization of in situ ice phenology observations in future interdisciplinary studies. These ice records represent some of the longest climate observations directly collected by people. We highlight the importance of applying the same definition of ice-on and ice-off within a lake across the time-series, regardless of how the ice is observed, to broaden our understanding of ice loss across vast spatial and temporal scales.
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| 11. |
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| 13. |
- Villarroel-Schneider, J., et al.
(författare)
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Techno-Economic Study of a Biogas-Based Polygeneration Plant for Small Dairy Farms in Central Bolivia
- 2020
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Ingår i: Renewable Energy and Sustainable Buildings. - Cham : Springer. - 9783030184872 - 9783030184889 ; , s. 675-687
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Bokkapitel (refereegranskat)abstract
- This paper presents a techno-economic feasibility study of a polygeneration plant proposed for an association of dairy farmers in Bolivia. The systems have been designed in an integrated approach and are based on the resource recovery utilizing available cow dung. The production of biogas is proposed using “low cost” tubular digesters. The biogas is used for the production of electricity and heat in a 40 kWel internal combustion engine. Heat from the exhaust gas is recovered to drive an absorption cooling system for milk refrigeration and for a bio-slurry drying system. The final services are biogas, electricity, cooling and fertilizers. The techno-economic analysis focuses on determining the levelized cost of the services and compare them with the subsidized and non-subsidized prices of other competitive services in the market. Sensitivity analyses for the services prices are carried out to see the influence of the feedstock handling cost and the subsidies on investment capital. Once the selling prices of the services are defined, the payback period of investment capital is determined. The results show that the biogas and electricity costs were found lower than the subsidized prices of similar services in the market while the cost of cooling was found slightly higher. From the sensitivity analysis we have that the feedstock handling cost can be increased from 10 to 18 USD/ton while maintaining the biogas price below the subsidized LPG price, and applying subsidies to the investment capital allows reducing the rest of the services costs. The payback period is around 3.5 years when a subsidy of 15% is applied in the investment capital and the services are sold at the subsidized prices of the conventional services. Our study has shown that under the conditions of the Bolivian market it is feasible the installation of a polygeneration plant. On the other hand, a market without or with reduced subsidies for the conventional services makes the proposed system more feasible and competitive.
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| 14. |
- Vukusic, J., et al.
(författare)
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MOVPE-grown GaInNAsVCSELs at 1.3 mu m with conventional mirror design approach
- 2003
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 39:8, s. 662-664
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Tidskriftsartikel (refereegranskat)abstract
- 1.3 mum oxide confined GaInNAs VCSELs designed using the same design philosophy used for standard 850 nm VCSELs is presented. The VCSELs have doped mirrors, with graded and highly doped interfaces, and are fabricated using production-friendly procedures. Multimode VCSELs (I I mum oxide aperture) with an emission wavelength of 1287 nm have a threshold current of 3 mA and produce I mW of output power at 20degreesC. The maximum operating temperature is 95degreesC. Emission at 1303 nm with I mW of output power and a threshold current of 7 mA has been observed from VCSELs with a larger detuning between the gain peak and the cavity resonance.
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| 15. |
- Asplund, Carl, et al.
(författare)
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1260 nm InGaAs vertical-cavity lasers
- 2002
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 38:13, s. 635-636
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication and performance of highly strained double-quantum well InGaAs/GaAs vertical-cavity lasers with record-long emission wavelength of 1260 nm at room temperature is reported. Depending on device diameter, the minimum threshold current is in the low mA-regime while the maximum output power exceeds 1 mW. The devices work continuous-wave over a wide temperature range of at least 10-120degrees C.
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| 16. |
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| 17. |
- Brodersen, Jakob, et al.
(författare)
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Short-and long term niche segregation and individual specialization of brown trout (Salmo trutta) in species poor Faroese lakes
- 2012
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Ingår i: Environmental Biology of Fishes. - : Springer Science and Business Media LLC. - 0378-1909 .- 1573-5133. ; 93:3, s. 305-318
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Tidskriftsartikel (refereegranskat)abstract
- Trophic niche divergence is considered to be a major process by which species coexistence is facilitated. When studying niche segregation in lake ecosystems, we tend to view the niche on a one-dimensional pelagic-littoral axis. In reality, however, the niche use may be more complex and individual fidelity to a niche may be variable both between and within populations. In order to study this complexity, relative simple systems with few species are needed. In this paper, we study how competitor presence affects the resource use of brown trout (Salmo trutta) in 11 species-poor Faroese lakes by comparing relative abundance, stable isotope ratios and diet in multiple habitats. In the presence of three-spined sticklebacks (Gasterosteus aculeatus), a higher proportion of the trout population was found in the pelagic habitat, and trout in general relied on a more pelagic diet base as compared to trout living in allopatry or in sympatry with Arctic charr (Salvelinus alpinus). Diet analyses revealed, however, that niche-segregation may be more complex than described on a one-dimensional pelagic-littoral axis. Trout from both littoral and offshore benthic habitats had in the presence of sticklebacks a less benthic diet as compared to trout living in allopatry or in sympatry with charr. Furthermore, we found individual habitat specialization between littoral/benthic and pelagic trout in deep lakes. Hence, our findings indicate that for trout populations interspecific competition can drive shifts in both habitat and niche use, but at the same time they illustrate the complexity of the ecological niche in freshwater ecosystems.
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| 18. |
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| 19. |
- Grundström, Hanna, et al.
(författare)
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Translation and validation of the Swedish version of the Birth Satisfaction Scale-Revised (BSS-R)
- 2023
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Ingår i: Midwifery. - : ELSEVIER SCI LTD. - 0266-6138 .- 1532-3099. ; 124
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Tidskriftsartikel (refereegranskat)abstract
- Background: Optimizing womens childbirth experience is essential for development of quality mother infant relationships. The Birth Satisfaction Scale-Revised ( BSS-R ) can be used to measure birth satisfaction. Aim: The current investigation sought to translate and validate a Swedish version of the BSS-R. Method: Following translation, a comprehensive psychometric validation of the Swedish - BSS-R ( SW-BSS-R ) was carried out using a multi-model, cross-sectional, between- and within-subjects design. Participants: A total of 619 Swedish-speaking women participated, from which 591 completed SW-BSS-R and were eligible for analysis. Data analysis: Discriminant, convergent, divergent and predictive validity, internal consistency, test-retest reliability, and factor structure were evaluated. Results: The SW-BSS-R was found to have excellent psychometric properties and hence is a valid translation of the original UK(English)-BSS-R . Important insights into relationships between mode of birth, posttraumatic stress disorder (PTSD), and postnatal depression (PND) were observed. Conclusions and implications for practice: The SW-BSS-R is a psychometrically valid translation of the original BSS-R and is suitable for use in a Swedish-speaking population of women. The study has also highlighted important dynamics between birth satisfaction and areas of significant clinical concern (i.e., mode of birth, PTSD and PND) in Sweden.
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| 20. |
- Hammar, M., et al.
(författare)
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1300-nm GaAs-based vertical-cavity lasers
- 2002
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - Brugge : SPIE. ; , s. 137-149
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Konferensbidrag (refereegranskat)abstract
- We compare GaInNAs and highly strained InGaAs quantum-wells (QWs) for applications in metal-organic vapor-phase epitaxy (MOVPE)-grown GaAs-based 1300-nm vertical-cavity lasers (VCLs). While the peak wavelength of InGaAs QWs can be extended by a small fraction of N, the luminescence efficiency degrades strongly with wavelength. On the other hand, using highly strained InGaAs QWs in combination with a large VCL detuning it is also possible to push the emission wavelength towards 1.3 ÎŒm. The optimized MOVPE growth conditions for such QW and VCL structures are discussed in some detail. It is noted that GaInNAs and InGaAs QWs preferably are grown at low temperature, but with quite different V/III ratios and growth rates. We also point out the importance of reduced doping concentration and growth temperature of the n-doped bottom distributed Bragg reflector to minimize optical loss and for compatibility with GaInNAs QWs. InGaAs VCLs with emission wavelengths beyond 1260 nm are demonstrated. This includes mW-range output power, mA-range threshold current and 10 Gb/s data transmission.
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| 27. |
- MALMQUIST, J, et al.
(författare)
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SYNTHESIS OF 2-[2-(3-AMINOPROPYL)-1,2-DICARBA-CLOSO-DODECABORAN(12)-1-YLMETHOXY]-1,3-PROPANEDIOL, A HYDROPHILICALLY SUBSTITUTED AMINOALKYL-O-CARBORANE
- 1994
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Ingår i: ACTA CHEMICA SCANDINAVICA. - : MUNKSGAARD INT PUBL LTD. ; 48:11
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A 1,2-dicarba-closo-dodecaborane(12) derivative, containing a hydrophilic diol group and an amino group 2-[2-(3-aminopropyl)-1,2-dicarba-closo-dodecaboran(12)-l-ylmethoxy]-1,3-propanediol (1a), has been synthesised from the dibenzyl ether of 2-[1,2-dicar
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| 28. |
- Mogg, S., et al.
(författare)
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1.3-ÎŒm InGaAs(N)/GaAs vertical-cavity lasers
- 2003
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - San Jose, CA : SPIE. ; , s. 139-151
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Konferensbidrag (refereegranskat)abstract
- In this work we present performance characteristics of metalorganic vapor-phase epitaxy grown GaInNAs and InGaAs quantum-well (QW) vertical-cavity lasers (VCLs) for 1.3-Όm applications. The InGaAs VCLs emit in a wavelength range from 1200 to somewhat above 1260 nm, while the GaInNAs VCLs operate from 1265 to 1303 nm. The InGaAs VCLs are based on highly strained InGaAs double QWs, with photoluminescence (PL) maximum at around 1190 nm, and extensive negative gain-cavity detuning. As a consequence, these devices are strongly temperature sensitive and the minimum threshold current is found at very high temperature (∌90-100°C). Both kind of VCLs work continuous-wave well above 100°C, and while the InGaAs VCLs reach slightly higher light output power, they show significantly larger threshold currents. In addition, the large device detuning also has profound effects on the high-frequency response. Nevertheless, for a 1260-nm device, 10 Gb/s transmission is demonstrated in a back-to-back configuration. We also show that by further optimization of the InGaAs QWs the PL peak wavelength can be extended to at least 1240 nm. The incorporation of such QWs in the present VCL structure should considerably improve the device performance, resulting in higher light output power, lower threshold current, and reduced temperature sensitivity with a shift of the minimum threshold current towards room temperature, thus approaching standard VCL tuning.
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| 34. |
- Viklander, Maria, et al.
(författare)
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Urban drainage and highway runoff in cold climates : conference overview
- 2003
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 48:9, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- This overview of research findings presented at the conference on urban drainage and highway runoff in cold climates starts with generation of urban runoff and snowmelt, followed by snowmelt and winter runoff quality, best management practices for urban snowmelt and winter runoff, and snow management in urban areas. Research on the urban hydrological cycle is lagging behind the needs in this field, particularly in terms of data availability. The current studies of winter urban runoff quality focus on road salts in the urban environment and their environmental effects. The needs for better source controls in salt applications, improved management of chloride-laden runoff, and selective adoption of environmentally safer alternative de-icers were reported. Adaptation of the conventional stormwater best management practices (BMPs) for winter operation remains a challenge. The first step in refining the existing BMPs for winter operation is to advance the understanding of their operation, as reported for some cases at the conference. Finally, snow management in urban areas may require local storage of fresh (unpolluted) snow and disposal of more polluted snow at central snow disposal sites.
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| 35. |
- Villarroel-Schneider, Johnny, et al.
(författare)
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Biogas based polygeneration plant options utilizing dairy farms waste : A Bolivian case
- 2020
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Ingår i: Sustainable Energy Technologies and Assessments. - : Elsevier. - 2213-1388 .- 2213-1396. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a comparative techno-economic feasibility analysis for two polygeneration plant solutions, applied to low-income dairy farms in Bolivia. The first option considers an internally fired microturbine (IFMT) and, the second, an internal combustion engine (ICE). They are integrated with an absorption refrigeration system and a fertilizer dryer. Biogas, produced with farms waste, fuels these power generators. The levelized costs of biogas for cooking, electricity, cooling and fertilizers were determined. The cost of biogas, for both options, was found to be 0.020 USD/kWh, which is lower than the subsidized price of LPG. The most competitive cost of electricity was determined for the ICE plant option; it was found to be 0.082 USD/kWh and is lower than the subsidized cost of fossil fuel-based electricity. The cost of cooling was found to be around 0.082 USD/kWh, which is slightly higher than the cost of cooling supplied by using grid electricity. In a realistic scenario, the shorter payback period was found to be 4.4 years for the ICE plant option. From this, the ICE-based plant was found as the most feasible option. Additionally, if no subsidies are applied to the fossil fuel-based services, the proposed polygeneration systems are a highly competitive alternative.
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| 36. |
- Villarroel-Schneider, Johnny, et al.
(författare)
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Energy self-sufficiency and greenhouse gas emission reductions in Latin American dairy farms through massive implementation of biogas-based solutions
- 2022
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 261, s. 115670-115670
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Tidskriftsartikel (refereegranskat)abstract
- The transition towards sustainable economies with improved resource efficiency is today’s challenge for all productive sectors. The dairy sector in Latin America is growing without considering a clear path for sustainable energy and waste management solutions. This study proposes integrated solutions through a waste-to-energy approach. The solutions consider biogas production (via cow manure) as the main energy conversion pathway; technology solutions include biodigesters, power generators, and combined heat and power systems that supply not only the energy services demanded by dairy farms (for cooking gas, electricity, refrigeration and hot water) but also provide organic fertilizers. Biogas’ potential was estimated to verify whether it can cover the energy demands of the farms, while the levelized costs of producing biogas and electricity were the indicators for the techno-economic evaluation of the solutions. Greenhouse gas emission reductions were estimated by following IPCC guidelines. Specifically, the proposed solutions lead to energy self-sufficiency in most dairy farms with relevant biogas and electricity costs in the range of 1.7–3.7 and 6–12 USD cents/kWh, respectively. In addition, implementing the proposed solutions in Latin American dairy farms would allow annual greenhouse gas emission reductions of 32.8 Mton CO2 eq. with an additional 17 Mton if widespread use of the supplied organic fertilizers is achieved.
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| 37. |
- Villarroel-Schneider, Johnny, et al.
(författare)
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Performance Analysis of a Small-Scale Biogas-Based Trigeneration Plant : An Absorption Refrigeration System Integrated to an Externally Fired Microturbine
- 2019
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 12:20
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Tidskriftsartikel (refereegranskat)abstract
- Trigeneration or combined cooling, heat and power (CCHP) systems fueled by raw biogas can be an interesting alternative for supplying electricity and thermal services in remote rural areas where biogas can be produced without requiring sophisticated equipment. In this sense, this study considers a performance analysis of a novel small-scale CCHP system where a biogas-fired, 5 kW(el) externally fired microturbine (EFMT), an absorption refrigeration system (ARS) and heat exchangers are integrated for supplying electricity, refrigeration and hot water demanded by Bolivian small dairy farms. The CCHP solution presents two cases, current and nominal states, in which experimental and design data of the EFMT performance were considered, respectively. The primary energy/exergy rate was used as a performance indicator. The proposed cases show better energy performances than those of reference fossil fuel-based energy solutions (where energy services are produced separately) allowing savings in primary energy utilization of up to 31%. Furthermore, improvements in electric efficiency of the EFMT and coefficient of performance (COP) of the ARS, identified as key variables of the system, allow primary energy savings of up to 37%. However, to achieve these values in real conditions, more research and development of the technologies involved is required, especially for the EFMT.
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