| 1. |
- Diamond, Miriam, et al.
(författare)
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Exploring the planetary boundary for chemical pollution
- 2015
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 78, s. 8-15
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Forskningsöversikt (refereegranskat)abstract
- Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if “unacceptable global change” is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social approaches to mitigate global chemical pollution that emphasize a preventative approach; coordinate pollution control and sustainability efforts; and facilitate implementation of multiple (and potentially decentralized) control efforts involving scientists, civil society, government, non-governmental organizations and international bodies.
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| 2. |
- Norrgran Engdahl, Jessica, et al.
(författare)
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Cats' Internal Exposure to Selected Brominated Flame Retardants and Organochlorines Correlated to House Dust and Cat Food
- 2017
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 51:5, s. 3012-3020
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Tidskriftsartikel (refereegranskat)abstract
- Pet cats may be used as a biomarker for assessing exposures to organohalogen compounds (OHCs) adsorbed to household dust in home environments. This study explores two exposure routes of OHCs, ingestion of OHCs (i) via house dust and (ii) via cat food. House dust from 17 Swedish homes and serum from the participating families' pet cats were collected, and cat food was purchased matching the diet reported. Paired samples of cat serum, house dust, and cat food were analyzed for brominated flame retardants/natural products (polybrominated diphenyl ethers (PBDEs), decabromobiphenyl (BB-209), decabromodiphenyl ethane (DBDPE), 2,4,6-tribromophenol (2,4,6-TBP), OH-PBDEs) and organochlorines (polychlorinated biphenyls (PCBs), 1,1-bis(4,4'-dichlorodipheny1)-2,2,2-trichloroethane (4,4'-DDT), 1,1-bis(4,4'-dichlorodiphenyl)-2,2-dichloroethene (4,4'-DDE), hexachlorobenzene (HCB), pentachlorophenol (PCP)). Significant correlations were found between serum and dust samples from the living rooms for BDE-47 (p < 0.035), BDE-99 (p < 0.035), and BDE-153 (p < 0.039), from the adult's bedroom for BDE-99 < 0.019) and from all rooms for BDE-99 (p < 0.020) and BB-209 (p < 0.048). This is the first time a correlation between cat serum levels and household dust has been established, a finding that supports the hypothesis that dust is a significant exposure route for cats. Serum levels were also significantly correlated with concentrations found in cat food for 6-OH-BDE47 (p < 0.002), 2,4,6-TBP (p < 0.035), and BB-209 (p < 0.007). DBDPE was found in high concentrations in all dust (median 154 pmol/g) and food samples (median 0.7 pmol/ig lw) but was below detection in serum samples, suggesting low or no bioavailability for DBDPE in cats.
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| 3. |
- Johannesson, Pär, 1969, et al.
(författare)
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A Robustness Approach to Reliability
- 2013
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Ingår i: Quality and Reliability Engineering International. - : Wiley. - 1099-1638 .- 0748-8017. ; 29:1, s. 17-32
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Forskningsöversikt (refereegranskat)abstract
- Reliability of products is here regarded with respect to failure avoidance rather than probability of failure. To avoid failures,we emphasize variation and suggest some powerful tools for handling failures due to variation. Thus, instead of technicalcalculation of probabilities from data that usually are too weak for correct results, we emphasize the statistical thinking thatputs the designers focus on the critical product functions.Making the design insensitive to unavoidable variation is called robust design and is handled by (i) identification andclassification of variation, (ii) design of experiments to find robust solutions, and (iii) statistically based estimations of propersafety margins.Extensions of the classical failure mode and effect analysis (FMEA) are presented. The first extension consists of identifyingfailure modes caused by variation in the traditional bottom–up FMEA analysis. The second variation mode and effect analysis(VMEA) is a top–down analysis, taking the product characteristics as a starting point and analyzing how sensitive thesecharacteristics are to variation.In cases when there is sufficient detailed information of potential failure causes, the VMEA can be applied in its mostadvanced mode, the probabilistic VMEA. Variation is then measured as statistical standard deviations, and sensitivities aremeasured as partial derivatives. This method gives the opportunity to dimension tolerances and safety margins to avoidfailures caused by both unavoidable variation and lack of knowledge regarding failure processes.
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| 4. |
- Liseau, René, 1949, et al.
(författare)
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O(18)O and C(18)O observations of rho Ophiuchi A
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 510:1, s. A98 -
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Tidskriftsartikel (refereegranskat)abstract
- Context. Contrary to theoretical expectation, surprisingly low concentrations of molecular oxygen, O-2, have been found in the interstellar medium. Telluric absorption makes ground based O-2 observations essentially impossible and observations had to be done from space. Millimetre-wave telescopes on space platforms were necessarily small, which resulted in large, several arcminutes wide, beam patterns. Observations of the (N-J = 1(1)-1(0)) ground state transition of O-2 with the Odin satellite resulted in a greater than or similar to 5 sigma detection toward the dense core rho OphA. At the frequency of the line, 119 GHz, the Odin telescope has a beam width of 10', larger than the size of the dense core. Aims. The precise nature of the emitting source and its exact location and extent are therefore unknown. The current investigation is intended to remedy this. Methods. Although the Earth's atmosphere is entirely opaque to low-lying O-2 transitions, it allows ground based observations of the much rarer (OO)-O-16-O-18 in favourable conditions and at much higher angular resolution with larger telescopes. In addition, rho OphA exhibits both multiple radial velocity systems and considerable velocity gradients. Extensive mapping of the region in the proxy (CO)-O-18 (J = 3-2) line can be expected to help identify the O-2 source on the basis of its line shape and Doppler velocity. Line opacities were determined from observations of optically thin (CO)-C-13-O-18 (J = 3-2). During several observing periods, two C18O intensity maxima in rho OphA were searched for (OO)-O-18 in the (2(1)-0(1)) line at 234 GHz with the 12m APEX telescope. These positions are associated also with peaks in the mm-continuum emission from dust. Results. Our observations resulted in an upper limit on the integrated O18O intensity of integral T-A* dv 16. Combining Odin's O-2 with the present (OO)-O-18 observations we infer an O-2 abundance 5 x 10(-7)
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| 5. |
- Wikman, Bengt, et al.
(författare)
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Estimation of constitutive parameters for powder pressing by inverse modelling
- 2006
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Ingår i: Structural and multidisciplinary optimization (Print). - : Springer Science and Business Media LLC. - 1615-147X .- 1615-1488. ; 31:5, s. 400-409
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Tidskriftsartikel (refereegranskat)abstract
- Powder metallurgy processes are used in many material technologies for manufacturing of a wide range of industrial parts. Products such as components for cars, cemented carbides and high-speed steels for mechanical cutting, magnets and soft magnetic materials, bearings and refractory metals are made from powder. These parts are manufactured by powder die pressing followed by sintering of the resulting green body in a furnace. Traditionally, experience-based methods have been used to design and adapt the processing variables for optimal performance. Cost savings can be made if the tool design can be based on reliable predictive numerical simulations of the powder compaction process. Computer modelling could aid process and design engineers in selecting and optimizing the best pressing route for many industrial components. The aim of the present work has been to develop an efficient way to determine the necessary constitutive model parameters of the numerical models by means of inverse modelling. An experiment for establishing input data to the inverse problem has been designed and validated. The objective function is formed based on the discrepancy in force-displacement data between the numerical model prediction and the experiment. Minimization of the objective function with respect to the material parameters is performed using an in-house optimization software shell which is built on a modified Nelder-Mead simplex method also known as the subplex method. The completed analyses show that the proposed approach can readily be used to determine material parameters.
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