| 1. |
- Bååth, Lars, 1948-
(författare)
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Noise Spectra from Wind Turbines
- 2013
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Ingår i: Renewable energy. - Oxford : Pergamon Press. - 0960-1481 .- 1879-0682. ; 57, s. 512-519
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents observations of audio noise in frequency range 20e20 000 Hz from wind turbines. The observations were performed around the theoretically calculated 40 dBA noise perimeter around the wind turbine farm at Oxhult, Sweden. This paper describes a newly designed and constructed a field qualified data acquisition system to measure spectra and total noise level of sound from wind turbines. The system has been calibrated at SP Borås. It is shown that it has a flat frequency response and is linear with amplitude and time.The total noise level (as integrated 20e20 000 Hz) is shown to be below 35 dBA (below the reference background noise at 36 dBA) at a 10 m altitude wind speed of 4e5 m/s. The measurements were made along the theoretical 40 dBA border at 8 m/s.It is concluded that the theoretical 40 dBA border seems reasonable calculated if the manufacturer specifications are used to extrapolate the sound level to correspond to 8 m/s at 10 m. Our data indicate that a simple sound propagation model is sufficient since the sound level is more affected by the nearby environment than the large scale forest structure. Also, the large scale forestry structure is bound to change with time and the error bars of measurements on total sound level are about 1 dBA, which is larger than any fine tuning with a more sophisticated model. More care should be taken to model the reflections from walls and other obstacles close to the microphones.The distribution of the spectral noise level around the turbine farm suggests that the noise originates from individual wind turbines closest to the measurement location rather than from the wind turbine farm as a whole. The spectra show narrow band spectral line features which do not contribute signifi-cantly to the total noise at this level. The narrow band features are only detectable at very long inte-gration time and at 1 Hz spectral resolution. The spectral features are typical to originate from mechanical noise.The spectral acquisition method described in this paper can be used as a field qualified system for sound measurements in forest areas. The high spectral resolution is a viable remote diagnostic method for mechanical faults in the turbine machinery. Future work will concentrate on these two areas.
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| 2. |
- Needham, Paul, 1948-
(författare)
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Hydrogen Bonding : Homing in on a Tricky Chemical Concept
- 2013
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Ingår i: Studies in history and philosophy of science. - : Elsevier BV. - 0039-3681 .- 1879-2510. ; 44:1, s. 51-66
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Tidskriftsartikel (refereegranskat)abstract
- The history of the hydrogen bond provides a good example of the of an important chemical concept. It illustrates the interplay between empirical and theoretical approaches to the problem of delimiting what has proved to be quite an elusive notion, with chemists whittling away at the particular sorts of case with a view to obtaining a precise, unitary concept. Even though there is a return to a more theoretically inspired notion in more recent research, empirical characterisations remain a feature of the report of a Task Group recently set up by the IUPAC to reconsider the definition of the hydrogen bond, and this situation-by no means unusual for chemical concepts and principles-is unlikely to change in the foreseeable future. These developments are reviewed in this paper, which includes an extended discussion of the enormous significance hydrogen bonding has for the philosopher's standard example of a "natural kind", water. There is little to suggest a reduction to what philosophers of physics are pleased to call fundamental principles, and the details raise further questions about what essentialists could possibly have in mind when talking about the microscopic essence of water.
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| 3. |
- Needham, Paul, 1948-
(författare)
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Nagel’s Analysis of Reduction : Comments in Defence as Well as Critique
- 2010
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Ingår i: Studies in history and philosophy of modern physics. - : Elsevier BV. - 1355-2198 .- 1879-2502. ; 41:2, s. 163-170
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Tidskriftsartikel (refereegranskat)abstract
- Despite all the criticism showered on Nagel's classic account of reduction, it meets a fundamental desideratum in an analysis of reduction that is difficult to question, namely of providing for a proper identification of the reducing theory. This is not clearly accommodated in radically different accounts. However, the same feature leads me to question Nagel's claim that the reducing theory can be separated from the putative bridge laws, and thus to question his notion of heterogeneous reduction. A further corollary to the requirement that all the necessary conditions be incorporated in an adequate formulation of the putative reducing theory is that the standard example of gas temperature is not reducible to average molecular kinetic energy. As originally conceived, Nagel's conception of reduction takes no account of approximate reasoning and this failure has certainly restricted its applicability, perhaps to the point of making it unrealistic as a model of reduction in science. I suggest approximation can be accommodated by weakening the original requirement of deduction without jeopardizing the fundamental desideratum. Finally, I turn to briefly consider the idea sometimes raised of the ontological reducibility of chemistry.
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| 4. |
- Needham, Paul, 1948-
(författare)
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The Source of Chemical Bonding
- 2014
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Ingår i: Studies in history and philosophy of science. - : Elsevier BV. - 0039-3681 .- 1879-2510. ; 45, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Developments in the application of quantum mechanics to the understanding of the chemical bond are traced with a view to examining the evolving conception of the covalent bond. Beginning with the first quantum mechanical resolution of the apparent paradox in Lewis's conception of a shared electron pair bond by Heitler and London, the ensuing account takes up the challenge molecular orbital theory seemed to pose to the classical conception of the bond. We will see that the threat of delocalisation can be overstated, although it is questionable whether this should be seen as reinstating the issue of the existence of the chemical bond. More salient are some recent developments in a longstanding discussion of how to understand the causal aspects of the bonding interaction the nature of the force involved in the covalent link which are taken up in the latter part of the paper.
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| 5. |
- Oliw, Ernst H., 1948-, et al.
(författare)
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Manganese lipoxygenase oxidizes bis-allylic hydroperoxides and octadecenoic acids by different mechanisms
- 2011
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier BV. - 1388-1981 .- 1879-2618. ; 1811:3, s. 138-147
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Tidskriftsartikel (refereegranskat)abstract
- Manganese lipoxygenase (MnLOX) oxidizes (11R)-hydroperoxylinolenic acid (11R-HpOTrE) to a peroxyl radical. Our aim was to compare the enzymatic oxidation of 11R-HpOTrE and octadecenoic acids with LOO-H and allylic C-H bond dissociation enthalpies of ~88 and ~87kcal/mol. Mn(III)LOX oxidized (11Z)-, (12Z)-, and (13Z)-18:1 to hydroperoxides with R configuration, but this occurred at insignificant rates (<1%) compared to 11R-HpOTrE. We next examined whether transitional metals could mimic this oxidation. Ce(4+) and Mn(3+) transformed 11R-HpOTrE to hydroperoxides at C-9 and C-13 via oxidation to a peroxyl radical at C-11, whereas Fe(3+) was a poor catalyst. Our results suggest that MnLOX oxidizes bis-allylic hydroperoxides to peroxyl radicals in analogy with Ce(4+) and Mn(3+). The enzymatic oxidation likely occurs by proton-coupled electron transfer of the electron from the hydroperoxide anion to Mn(III) and H(+) to the catalytic base, Mn(III)OH(-). Hydroperoxides abolish the kinetic lag times of MnLOX and FeLOX by oxidation of their metal centers, but 11R-HpOTrE was isomerized by MnLOX to (13R)-hydroperoxy-(9Z,11E,15Z)-octadecatrienoic acid (13R-HpOTrE) with a kinetic lag time. This lag time could be explained by two competing transformations, dehydration of 11R-HpOTrE to 11-ketolinolenic acid and oxidation of 11R-HpOTrE to peroxyl radical; the reaction rate then increases as 13R-HpOTrE oxidizes MnLOX with subsequent formation of two epoxyalcohols. We conclude that oxidation of octadecenoic acids and bis-allylic hydroperoxides occurs by different mechanisms, which likely reflect the nature of the hydrogen bonds, steric factors, and the redox potential of the Mn(III) center.
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| 6. |
- Alexanderson, Camilla, 1978, et al.
(författare)
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A single early postnatal estradiol injection affects morphology and gene expression of the ovary and parametrial adipose tissue in adult female rats.
- 2010
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Ingår i: The Journal of steroid biochemistry and molecular biology. - : Elsevier BV. - 1879-1220 .- 0960-0760. ; 122:1-3, s. 82-90
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Tidskriftsartikel (refereegranskat)abstract
- Events during early life can affect reproductive and metabolic functions in adulthood. We evaluated the programming effects of a single early postnatal estradiol injection (within 3h after birth) in female rats. We assessed ovarian and parametrial adipose tissue morphology, evaluated gene expression related to follicular development and adipose tissue metabolism, and developed a non-invasive volumetric estimation of parametrial adipose tissue by magnetic resonance imaging. Estradiol reduced ovarian weight, increased antral follicle size and number of atretic antral follicles, and decreased theca interna thickness in atretic antral follicles. Adult estradiol-injected rats also had malformed vaginal openings and lacked corpora lutea, confirming anovulation. Estradiol markedly reduced parametrial adipose tissue mass. Adipocyte size was unchanged, suggesting reduced adipocyte number. Parametrial adipose tissue lipoprotein lipase activity was increased. In ovaries, estradiol increased mRNA expression of adiponectin, complement component 3, estrogen receptor alpha, and glucose transporter 3 and 4; in parametrial adipose tissue, expression of complement component 3 was increased, expression of estrogen receptor alpha was decreased, and expression of leptin, lipoprotein lipase, and hormone-sensitive lipase was unaffected. These findings suggest that early postnatal estradiol exposure of female rats result in long-lasting effects on the ovary and parametrial adipose tissue at adult age.
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| 7. |
- Bidgoli, Hassan Haghparast, et al.
(författare)
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Pre-hospital trauma care resources for road traffic injuries in a middle-income country-A province based study on need and access in Iran.
- 2011
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Ingår i: Injury. - : Elsevier BV. - 0020-1383 .- 1879-0267. ; 42:9, s. 879-884
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Access to pre-hospital trauma care can help minimize many of traffic related mortality and morbidity in low- and middle-income countries with high rate of traffic deaths such as Iran. The aim of this study was to assess if the distribution of pre-hospital trauma care facilities reflect the burden of road traffic injury and mortality in different provinces in Iran. METHODS: This national cross-sectional study is based on ecological data on road traffic mortality (RTM), road traffic injuries (RTIs) and pre-hospital trauma facilities for all 30 provinces in Iran in 2006. Lorenz curves and Gini coefficients were used to describe the distributions of RTM/RTIs and pre-hospital trauma care facilities across provinces. Spearman rank-order correlation was performed to assess the relationship between RTM/RTI and pre-hospital trauma care facilities. RESULTS: RTM and RTIs as well as pre-hospital trauma care facilities were distributed unequally between different provinces. There was no significant association between the rate of RTM and RTIs and the number of pre-hospital trauma care facilities across the country. CONCLUSIONS: The distribution of pre-hospital trauma care facilities does not reflect the needs in terms of RTM and RTIs for different provinces. These results suggest that traffic related mortality and morbidity could be reduced if the needs in terms of RTM and RTIs were taken into consideration when distributing pre-hospital trauma care facilities between the provinces.
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| 8. |
- Ekberg, Christian, 1967, et al.
(författare)
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Using At-211 as internal alpha radiolysis source allowing for simple detection of radiolysis products
- 2010
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Ingår i: Radiation Physics and Chemistry. - : Elsevier BV. - 1879-0895 .- 0969-806X. ; 79:4, s. 454-456
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Tidskriftsartikel (refereegranskat)abstract
- The determination of radiolysis products is an important field both for the basic understanding of the radiolysis process and for process development. The latter case mainly dealing with processes for handling radioactive wastes. There are several kinds of radiolysis processes that originate from the different kinds of radiation. Gamma rays and high-energy beta has a high ability to penetrate barriers while alpha irradiation in principle has to be performed with the radiation emitting nuclide inside the actual sample. This can be a problem since most laboratories able to identify radiolysis products cannot handle alpha contaminated samples. In this paper we suggest the use of At-211 as internal alpha emitting radionuclide. Due to its short half-life and decay to more or less stable daughters the radiolysis products may be examined using normal equipment without causing contamination.
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| 9. |
- Forslund, Johanna, et al.
(författare)
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Does remediation save lives? - on the cost of cleaning up arsenic-contaminated sites in Sweden.
- 2010
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Ingår i: The Science of the total environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 408:16, s. 3085-91
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Tidskriftsartikel (refereegranskat)abstract
- Sweden has only just begun remediation of its many contaminated sites, a process that will cost an estimated SEK 60,000 million (USD 9100 million). Although the risk assessment method, carried out by the Swedish EPA, is driven by health effects, it does not consider actual exposure. Instead, the sites are assessed based on divergence from guideline values. This paper uses an environmental medicine approach that takes exposure into account to analyse how cancer risks on and near arsenic-contaminated sites are implicitly valued in the remediation process. The results show that the level of ambition is high. At 23 contaminated sites, the cost per life saved varies from SEK 287 million to SEK 1,835,000 million, despite conservative calculations that in fact probably underestimate the costs. It is concluded that if environmental health risks are to be reduced, there are probably other areas where economic resources can be used more cost-effectively.
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| 10. |
- Gabre, Pia, et al.
(författare)
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Simplified methods of topical fluoride administration: effects in individuals with hyposalivation.
- 2013
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Ingår i: Special Care in Dentistry. - : Wiley. - 1754-4505 .- 0275-1879. ; 33:3, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to compare fluoride (F) levels in individuals with normal salivary secretion and hyposalivation in connection with their use of F solutions and toothpaste. Seven individuals with normal salivation and nine with hyposalivation rinsed with 0.2% NaF solution for 1 minute. In addition, individuals with hyposalivation performed the following: (i) 0.2% NaF rinsing for 20 seconds, (ii) rubbing oral mucosa with a swab soaked with 0.2% NaF solution, and (iii) brushing with 5,000 ppm F (1.1% NaF) toothpaste. Subjects characterized by hyposalivation reached approximately five times higher peak values of F concentrations in saliva after 1 minute rinsing with the F solution and higher area under the curve (AUC) values. The simplified methods exhibited the same AUC values as did 1 minute of rinsing. Brushing with 5,000 ppm F toothpaste resulted in higher AUC values than did the simplified methods. The F concentrations reached higher levels in individuals with hyposalivation compared to those with normal salivation. The simplified methods tested showed similar effects as conventional methods.
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