| 1. |
- Aasa, Björn, et al.
(författare)
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A characterisation of pain, disability, kinesiophobia and physical capacity in patients with predominantly peripherally mediated mechanical low back pain
- 2011
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Ingår i: Physiotherapy. - 0031-9406 .- 1873-1465. ; 97:Suppl. 1, s. eS18-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The specific objectives were to: 1) describe the level of pain intensity, disability, activity limitation, kinesiophobia and physical capacity in patients with predominantly peripherally mediated mechanical back pain, and 2) investigate whether differences between these patients in physical and psychosocial factors can be distinguished when the patients are further sub-grouped.Relevance: To improve assessment among patients with chronic low back pain (CLBP) it is important to investigate the prevalence of physical and psychosocial features in homogenous sub-groups.Participants: Seventy-one patients with CLBP, 20-60 years old, with peripherally mediated mechanical pain at the the moment for the study, were included and each patient was sub-classified into one of five sub-groups based on their pain behaviour and functional movement pattern (flexion n=20, flexion/lateral shift, n=11, active extension n=23 , passive extension n=8, and multidirectional pattern n=9).Methods: Data on pain intensity (Visual Analogue Scale), disability (the Roland and Morris Questionnaire), activity limitation (the Patient Specific Functional Scale), kinesiophobia (the Tampa Scale of Kinesiophobia) and physical capacity (lifting capacity and trunk extensor endurance) was collected.Analysis: Mean and standard deviation for parametric and median and interquartile range for non-parametric data were used for descriptive statistics. One-way ANOVA for normally distributed data and Kruskal-Wallis for non-normally distributed data were used for analyses of differences between the sub-groups. The subjects were also divided into two age-groups (20-40 and 41-60 years) and measures of physical capacity were compared to women and men at the ages of 34 and 50, respectively, in the general Swedish population using one sample T-test.Results: The patients reported low to moderate pain intensity (3.1/10±2.4), disability (RMDQ (7.27/24 ±4.2) and kinesiophobia (33.4/68 ±7) and these levels were lower than reported levels in other studies including more heterogenous groups of patients with CLBP. The patiens reported activity limitations (PSFS 13/30±23). Lifting capacity and trunk extensor endurance were significantly lower than in the general population in the youngest age-group. No significant differences in pain intensity, disability, kinesiophobia or physical capacity were found between the sub-groups.Conclusions: This research highlights that patients with predominantly peripherally mediated mechanical back pain may differ from other sub-groups of patients with CLBP (e.g., patients with central sensitization as dominating pain mechanism) regarding physical and psychosocial factors. The individual variation in pain intensity, disability, kinesiophbia and physical capacity among the patients indicates the importance to assess these factors in every patient. Due to the fact that there were few patients in the sub-groups, further research is necessary to explore whether there are differences, that we were not able to disingjish, between patients with different movement patterns.
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| 2. |
- Abdikalikova, Zamira, et al.
(författare)
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Boundedness and compactness of the embedding between spaces with multiweighted derivatives when 1
- 2011
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Ingår i: Czechoslovak Mathematical Journal. - : Institute of Mathematics, Czech Academy of Sciences. - 0011-4642 .- 1572-9141. ; 61:1, s. 7-26
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Tidskriftsartikel (refereegranskat)abstract
- We consider a new Sobolev type function space called the space with multiweighted derivatives W-p(n),(alpha) over bar, where (alpha) over bar = (alpha(0), alpha(1), ......, alpha(n)), alpha(i) is an element of R, i = 0, 1,......,n, and parallel to f parallel to W-p(n),((alpha) over bar) = parallel to D((alpha) over bar)(n)f parallel to(p) + Sigma(n-1) (i=0) vertical bar D((alpha) over bar)(i)f(1)vertical bar, D((alpha) over bar)(0)f(t) = t(alpha 0) f(t), d((alpha) over bar)(i)f(t) = t(alpha i) d/dt D-(alpha) over bar(i-1) f(t), i = 1, 2, ....., n. We establish necessary and sufficient conditions for the boundedness and compactness of the embedding W-p,(alpha) over bar(n) -> W-q,(beta) over bar,(m) when 1 <= q < p < infinity, 0 <= m < n
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| 5. |
- Adey, E.A., et al.
(författare)
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Corporate social responsibility within the mining industry : case studies from across Europe and Russia
- 2011
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Ingår i: Proceedings of the Aachen International Mining Symposia (AIMS). - Aachen : Aachen University. ; , s. 153-170
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Konferensbidrag (refereegranskat)abstract
- Responsible mining requires a company to engage with local communities throughout all stages of their operations, from exploration phases through to post mining planning. Assessment of current and potential future social impacts allows a company to maximize the positive impacts they can have on a community, whilst minimizing negative social impacts from mining. Initiating and upholding effective stakeholder relations are key to a company`s ability to obtain and maintain their "social license" to operate. The level of interaction between mining companies and stakeholders, including local communities, varies substantially between and within countries. As part of the EU funded Framework 7 "ImpactMin" Project (Impact Monitoring of Mineral Resources Exploitation), we have examined the level of community engagement in mining and related processing industries at sites across Europe, including Romania (Rosia Montana), Sweden (Kristineberg), the UK (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These sites reflect different stages in mining and therefore reveal a diverse range of issues and differing levels of community engagement. Our aim has been to focus not only on how practice varies, but also to try to explain the complex reasons behind the relationships that exist between mining companies and different stakeholders. Findings of questionnaires undertaken across the sites (between June - October 2010), and results of interviews and focus groups of different people linked to the mining industry, will also be discussed. The expectations that "mining" communities have of their local mining company vary substantially, directly relating to what the community believes the mine company owes them. These examples highlight that the notion of corporate social responsibility in the mining sector in Europe and Russia is fluid and changes according to the differing expectations and goals of stakeholders. We will present highlights of initial results. For example, Rosia Montana Gold Corporation, in Romania, is trying to reopen closed state gold mines. They have seen international media attention relating to campaigns by NGOs to oppose the mines reopening. Our results will help reveal what samples of different stakeholder groups really think of the mines reopening. This example contrasts distinctly with a mine in Kristineberg, Sweden, where Kristineberg village was built alongside the mine. There are now distinct issues felt within the community due to the decline in the number of people employed at the mine.
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| 6. |
- Adolfsson, Daniel, et al.
(författare)
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Cementitious phases in ladle slag
- 2011
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 82:4, s. 398-403
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Tidskriftsartikel (refereegranskat)abstract
- Ladle slag is an internal by-product generated within the steelmaking industry during the refining of steel. The realisation of beneficial inherent properties of ladle slag as a binder supplement or substitute material is believed to be advantageous with respect to both economy and environment for steelmakers. For this reason, the current study has focused on highlighting the properties of ladle slag that are pertinent to the formation of calcium aluminate hydrates. Three fractions of ladle slag, two of which were based on different slag formers, have been characterised using XRF, XRD and calorimetric analysis. Commonly known hydraulic minerals such as mayenite, tricalcium aluminate and dicalcium silicate were detected during analysis. An important aspect in the utilisation of ladle slag is the slag handling methodology. Therefore, this study also highlights and discusses the need to reconsider slag handling procedures concerning unnecessary exposure to weathering and the possible need for further processing of the slag in order to better employ the inherent hydraulic properties of this material.
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| 7. |
- Adolfsson, Daniel
(författare)
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Cementitious properties of steelmaking slags
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present study is directed towards the use of steelmaking slags as raw material for sulphoaluminate belite cement (SAB). Another important objective was to characterise the cementitious properties of phases in ladle furnace slag (LFS) specifically the calcium aluminates. Mayenite (C12A7) is considered one of the most important calcium aluminate in LFS, and since comparatively limited data on the kinetic properties of this phase are available, it was decided to study C12A7 more closely with regard to both particle size and temperature sensitivity. The behaviour of high-temperature reactions of tested SAB mixtures was investigated using thermogravimetric analysis coupled with a quadrupole mass spectrometer. Mineralogical observations were carried out with x-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results proved that steelmaking slags have the potential to work as raw material, since sulphoaluminate (C4A3 S ) along with polymorphs of dicalcium silicate (C2S) and ferrite phase (C4AF) were detected after firing at 1200ºC in an air atmosphere. The hydration properties of the specimens were analysed through conduction calorimetry, and compressive strength of specimens hydrated for 2 and 28 days. The compressive strength was in accordance with that suggested in the literature for slow hardening SAB cement. Both mixtures tested behaved the same with regard to heat development as well as the amount of ettringite (AFt) formed during the first 24 hours of the hydration. The formation of AFt was characterised with both differential scanning calorimeter (DSC) and XRD. The crystallographic distribution in LFS samples was quantified using Rietveldanalysis. Calorimetric studies were performed at 20, 25 and 30°C in order to calculate the activation energy of hydration and thereby to suggest a kinetic model for tested compositions within this temperature interval. In addition to heat of hydration, compressive strength tests were completed on mortar prisms of LFS, and LFS in a blend with ground granulated blast furnace slag (GGBFS) which hydrated for 2, 7 and 28 days. Both compositions reached acceptable early strengths, whereas, after 28 days hydration, the blend was superior to neat LFS. Related activation energy was according to the Avrami-Erofeev model determined to 58 kJ/mol for the LFS and 63 kJ/mol for the blend. Corresponding calorimetric studies at the same temperatures were performed on a fine and coarse size fraction (Fraction A and Fraction B) of a synthesised C12A7. The purity was confirmed by XRD, and the hydraulic behaviour was investigated in excess water with respect to the dissolution. The apparent activation energy was calculated to 33 and 79 kJ/mol, respectively, for Fractions A-B using the Avrami-Erofeev model. From the model, it was also concluded that the acceleration period can be ascribed to a phase-boundary controlled mechanism. The principal calcium aluminate hydrates obtained were C2AH8 and C2AH7.5, and it was further observed that C12A7 is accompanied by an anomalous setting behaviour much like monocalcium aluminate (CA), and that the decomposition of C2AH8 to C2AH7.5 develops more slowly with higher surface area, specifically at 20 and 30°C.
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| 8. |
- Adolfsson, Daniel, et al.
(författare)
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Influence of mineralogy on the hydraulic properties of ladle slag
- 2011
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Ingår i: Cement and Concrete Research. - : Elsevier BV. - 0008-8846 .- 1873-3948. ; 41:8, s. 865-871
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Tidskriftsartikel (refereegranskat)abstract
- The present study is aimed at investigating the hydraulic characteristics of ladle furnace slag (LFS), under the pretence of using LFS as a cement substitute in certain applications. Furthermore, LFS has been considered as a possible activator in a blend containing 50% LFS, and 50% ground granulated blast furnace slag (GGBFS). Phases detected in LFS were quantified using Rietveld analysis. Calorimetric studies were performed at 20, 25 and 30 °C in order to calculate the apparent activation energy of hydration and thereby to suggest a kinetic model for the tested compositions within this temperature interval. In addition, compressive strength tests were performed on mortar prisms made with LFS, and LFS/GGBFS which had hydrated for 2, 7 and 28 days. Both compositions reached acceptable early strengths, (e.g. LFS, 33.1 MPa, and LFS/GGBFS, 17.9 MPa, after 2 days), but after 28 days hydration the blend was superior to neat LFS. Related apparent activation energies were determined using an Avrami–Erofeev model and gave Ea = 58 kJ/mol for neat LFS and Ea = 63 kJ/mol for the blend. The results imply that LFS or a LFS/GGBFS blend can be favourably used as supplement in binder applications such as binder in by-product metallurgical briquettes, which are used as recycle to the blast furnace or basic oxygen furnace depending on the specific briquette composition.
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| 9. |
- Ahmadi, Alireza, et al.
(författare)
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Cost based risk analysis to identify inspection and restoration intervals of hidden failures subject to aging
- 2011
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Ingår i: IEEE Transactions on Reliability. - 0018-9529 .- 1558-1721. ; 60:1, s. 197-209
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Tidskriftsartikel (refereegranskat)abstract
- The analytical model presented in this paper aims to study possible maintenance strategies considering risk constrains, to preserve or assure availability of hidden functions of a repairable unit in aircraft systems considering ageing effect. The paper discusses two known strategies for hidden failure management aviation and other high risk industries, namely Failure Finding Inspection (FFI), and a combination of a series of FFI and restoration after a specific number of FFI cycles ( i.e., FFI-Rs strategy). Based on discussions, the paper introduces a new approach named Dynamic Failure Finding Inspection strategy (DFFI) to assure the acceptable level of risk and also the unit's hidden function availability continuously . The paper presents analytical methods to estimate optimal FFI, and optimal thresholds for restoration of degradation (refreshing risk level) within FFI-Rs strategy. It also discusses criteria used to select appropriate thresholds to change the FFI intervals within DFFI strategy, i.e. reducing inspection intervals after specific thresholds, to reduce the risk. The method is based on the mean proportion of time i.e. (Mean Functional Dead Time, MFDT) that the unit is not functioning during the inspection intervals and the average unavailability behavior within the restoration/discard period. The proposed method considers inspection, repair, and restoration times, and takes in to account costs associated with inspection, repair, restoration, potential losses due to non-availability of aircraft due to maintenance downtime or accident often caused multiple failures.
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| 10. |
- Ahmadi, Alireza, et al.
(författare)
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Risk based maintenance decision for periodically tested repairable components subject to hidden failure
- 2011
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Ingår i: Proceedings of 2nd International Conference on Reliability, Safety and Hazard - ICRESH 2010. - Piscataway, NJ : IEEE Communications Society. - 9781424483440 - 9781424483433 ; , s. 197-204
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Konferensbidrag (refereegranskat)abstract
- This paper aims to develop a graphical method to facilitate the identification of risk and cost of postponement of restoration for repairable components which are periodically tested and whose failures are hidden, i.e, are detectable by inspection or upon demand. The paper focuses on the items which are under aging, however, the methodology is flexible to implement for any aging pattern. The paper considers Failure Finding Inspection (FFI) with restoration actions (FFI+Res), for the “safety effect” categories of hidden failures. As-bad-as-old (ABAO) inspection effectiveness and as-good-as-new (AGAN) restoration effectiveness are considered. In case of repair due to findings by inspection, as-bad-as-old repair effectiveness is considered. The graphical methodology proposed in this paper considers inspection and repair times, as well as the costs associated with accident, inspection, repair, and restoration, and takes into account the opportunity losses due to the maintenance downtime. The analytical approach is based on the Mean Fractional Dead Time. In the case of an operational limit, when it is not possible to remove the unit for restoration, or one needs to use the unit longer than the expected operating time, the paper introduces an approach to analyzing the possibility of and conditions for providing an extension to the restoration interval that satisfies the risk constraints and the business requirements at the same time.
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