| 1. |
- Abele, H., et al.
(författare)
-
Particle physics at the European Spallation Source
- 2023
-
Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 1023, s. 1-84
-
Forskningsöversikt (refereegranskat)abstract
- Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world’s brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).
|
|
| 2. |
- Aguilar, J., et al.
(författare)
-
Study of nonstandard interactions mediated by a scalar field at the ESSnuSB experiment
- 2024
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 109:11
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study scalar mediator induced nonstandard interactions (SNSIs) in the context of the ESSnuSB experiment. In particular, we study the capability of ESSnuSB to put bounds on the SNSI parameters and also study the impact of SNSIs in the measurement of the leptonic CP phase δCP. Existence of SNSIs modifies the neutrino mass matrix and this modification can be expressed in terms of three diagonal real parameters (ηee, ημμ, and ηττ) and three off-diagonal complex parameters (ηeμ, ηeτ, and ημτ). Our study shows that the upper bounds on the parameters ημμ and ηττ depend upon how Δm312 is minimized in the theory. However, this is not the case when one tries to measure the impact of SNSIs on δCP. Further, we show that the CP sensitivity of ESSnuSB can be completely lost for certain values of ηee and ημτ for which the appearance channel probability becomes independent of δCP.
|
|
| 3. |
- Basarir, Hakan, et al.
(författare)
-
Assessment of slope stability using fuzzy sets and systems
- 2013
-
Ingår i: International Journal of Mining, Reclamation and Environment. - : Informa UK Limited. - 1748-0930 .- 1748-0949. ; 27:5, s. 312-328
-
Tidskriftsartikel (refereegranskat)abstract
- To assess the stability of slopes, mining and geotechnical engineers frequently use empirical rock mass classification and characterisation systems. These methods are practical and often very useful in the preliminary design stage. Slope mass rating (SMR) system is one of the commonly used empirical methods to assess the stability of slopes. The SMR is obtained correcting basic rock mass rating (RMR) using four joint adjustment factors that consider the geomechanical relationship between the slope face and the joint affecting rock mass as well as the excavation method used. The factors included in the SMR system such as basic RMR, and correction factors involve some drawbacks such as uncertainties sourced from qualitative criteria, sharp class boundaries and fixed rating scales. These drawbacks are sourced from the complex nature of rock mass. To deal with these uncertainties, the fuzzy set theory is applied in this study to reliably determine basic RMR and adjustment factors. It was seen that fuzzy set theory can sufficiently cope with the common drawbacks in the determination of factors included in the SMR system.
|
|
| 4. |
- Burgman, A., et al.
(författare)
-
The ESSnuSB Design Study: Overview and Future Prospects
- 2023
-
Ingår i: Universe. - : MDPI. - 2218-1997. ; 9:8
-
Forskningsöversikt (refereegranskat)abstract
- ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the second maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, and the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.
|
|
| 5. |
- Burgman, A., et al.
(författare)
-
The European Spallation Source neutrino super-beam conceptual design report
- 2022
-
Ingår i: The European Physical Journal Special Topics. - : Springer Nature. - 1951-6355 .- 1951-6401. ; 231:21, s. 3779-3955
-
Forskningsöversikt (refereegranskat)abstract
- A design study, named ESSνSB for European Spallation Source neutrino Super Beam, has been carried out during the years 2018–2022 of how the 5 MW proton linear accelerator of the European Spallation Source under construction in Lund, Sweden, can be used to produce the world’s most intense long-baseline neutrino beam. The high beam intensity will allow for measuring the neutrino oscillations near the second oscillation maximum at which the CP violation signal is close to three times higher than at the first maximum, where other experiments measure. This will enable CP violation discovery in the leptonic sector for a wider range of values of the CP violating phase δCPδCP and, in particular, a higher precision measurement of δCPδCP. The present Conceptual Design Report describes the results of the design study of the required upgrade of the ESS linac, of the accumulator ring used to compress the linac pulses from 2.86 ms to 1.2 μs, and of the target station, where the 5 MW proton beam is used to produce the intense neutrino beam. It also presents the design of the near detector, which is used to monitor the neutrino beam as well as to measure neutrino cross sections, and of the large underground far detector located 360 km from ESS, where the magnitude of the oscillation appearance of νe from νμ is measured. The physics performance of the ESSνSB research facility has been evaluated demonstrating that after 10 years of data-taking, leptonic CP violation can be detected with more than 5 standard deviation significance over 70% of the range of values that the CP violation phase angle δCPδCP can take and that δCPδCP can be measured with a standard error less than 8° irrespective of the measured value of δCPδCP. These results demonstrate the uniquely high physics performance of the proposed ESSνSBESSνSB research facility.
|
|
| 6. |
- Elhami, Ehsan, et al.
(författare)
-
2D modeling of the Kristineberg mine stope
- 2012
-
Konferensbidrag (refereegranskat)abstract
- Mining operations at the Kristineberg Mine approaches depths of more than 1300 m. Severe ground conditions are consequently expected due to the combination of weak rock formations and relatively high in-situ stresses. The required support techniques, however, are not unique and depend on the ground deformation characteristics. On the other hand, the complex geology of the mining zone induces different types and magnitudes of failures. As a result, to improve the support performance, the possible ground conditions which may arise from varieties of geological parameters at the mine need to be characterized. Among different geological parameters at the mine, the location of the rock formations is seen to be an important factor, influencing the deformation behavior of the rock mass. The aim of this study is to increase the understanding of how the rock mass behavior changes due to the location of the rock formations. The study is performed through numerical modeling of an unsupported stope using FLAC2D; the required input data are determined based on the field observations and the corresponding literatures. Then, the modeled deformation behavior of the stope is studied through “Parameter Analysis”. The results, which show the sensitivity of the ground deformation to the location of the surrounding rock formations, can be used in future support design analysis.
|
|
| 7. |
- Idris, Musa Adebayo, et al.
(författare)
-
Comparison of different probabilistic methods for analyzing stability of underground rock excavations
- 2016
-
Ingår i: Electronic Journal of Geotechnical Engineering. - : Mete Öner. - 1089-3032. ; 21:21, s. 6555-6585
-
Tidskriftsartikel (refereegranskat)abstract
- Stability analyses of underground rock excavations are often performed using traditional deterministic methods. In deterministic methods the mean or characteristics values of the input parameters are used for the analyses. These method neglect the inherent variability of the rock mass properties in the analyses and the results could be misleading. Therefore, for a realistic stability analyses probabilistic methods, which consider the inherent variability of the rock mass properties, are considered appropriate. A number of probabilistic methods, each based on different theories and assumptions have been developed for the analysis of geotechnical problems. Geotechnical engineers must therefore choose appropriate probabilistic method to achieve a specific objective while taking into account simplicity, accuracy and time efficiency. In this study finite difference method was combined with five different probabilistic methods to analyze the stability of an underground rock excavation. The probabilistic methods considered were the Point Estimate Method (PEM), the Response Surface Method (RSM), the Artificial Neural Network (ANN), the Monte Carlos Simulation (MCS), and the Strength Classification Method (SCM). The results and the relative merits of the methods were compared. Also the general advantages of the probabilistic method over the deterministic method were discussed. Though the methods presented in this study are not exhaustive, the results of this study will assist in the choice of appropriate probabilistic methods for the analysis of underground rock excavations.
|
|
| 8. |
- Idris, Musa Adebayo, et al.
(författare)
-
Consideration of the rock mass property variability in numerical modelling of open stope stability
- 2012
-
Ingår i: Föredrag vid Bergmekanikdag i Stockholm, 12 mars 2012. - Stockholm : Stiftelsen bergteknisk forskning - Befo. ; , s. 111-123
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a probabilistic approach for modelling complex rock masses wherethe intrinsic properties are highly variable. For this study a complex orebody in aCanadian mine is used. The mechanical properties of the host rock and the ore in thismine are found to be intrinsically variable with high contrast between their mechanicalproperties. It is apparent that the use of traditional deterministic methods to study thebehaviour of the open stopes is not appropriate for this mine. Hence, in this study aprobabilistic approach is adopted which allows the propagation of the variability of theinput parameters in the numerical modelling. Three different approaches were used toanalyze the stability of the open stopes based on the distribution of the different materialproperties of the rock mass. The results of the analysis using the three methods werecompared and the limitations and the potentials of each of the methods were discussed.The study provides insight into the significance of the rock mass property variability inthe numerical modelling of open stope stability and different ways that it could beincorporated into the modelling.
|
|
| 9. |
- Idris, Musa Adebayo, et al.
(författare)
-
Numerical analyses of the effects of rock Mass property variability on open stope stability
- 2011
-
Ingår i: 45th US Rock Mechanics /Geomechanics Symposium. - San Francisco, CA, USA : ARMA, American Rock Mechanics Association.
-
Konferensbidrag (refereegranskat)abstract
- The rock mass is intrinsically variable in its physical and mechanical properties which makes it complex. This complexity is evident from the spatial random distribution of the properties from any site characterization program. The precise values for these properties are never known in most cases hence most geotechnical mine designs are based on fixed or discrete values of rock mass properties for stability analysis. This traditional deterministic approach neither reflects the inherent variability nor the uncertainty in the rock mass properties. Therefore, it is desirable to utilize a probabilistic approach which provides a range of possible results based on the variability in the rock mass properties. Understanding the effect of this random distribution and variability of the properties on stope stability is essential for more realistic mine design. In this study, a series of numerical analyses using the explicit finite difference element code FLAC, have been conducted to study the effect of the random distribution and variability of rock mass properties on the stope stability. The rock mass in the FLAC model is represented by different material properties randomly distributed to each zone. In order to compare the results, fixed average values of the material properties were also used for the FLAC model in another simulation. The results clearly indicate that rock mass property variability does affect the stope stability and that a deterministic approach to stope stability analysis could lead to conservative results.
|
|
| 10. |
- Idris, Musa Adebayo, et al.
(författare)
-
Probabilistic analysis of open stope stability using numerical modelling
- 2011
-
Ingår i: International Journal of Mining and Mineral Engineering. - 1754-890X .- 1754-8918. ; 3:3, s. 194-219
-
Tidskriftsartikel (refereegranskat)abstract
- A probabilistic approach is presented for the analysis of open stopestability. The approach considers the inherent variability and uncertainty whichare typical of rock mass properties. In this study, a series of numerical analyseswere performed using FLAC to study the stability of open stopes while takinginto account the variability in the rock mass properties. The rock mass wasdivided into six strength classes: three classes for the host rock and threeclasses for the massive sulphide ore. Each class was randomly distributed to theelements in the FLAC model. The host rock-to-massive sulphide ore ratio isenvisaged to have a strong influence on the stope. To verify this, three casesof different ore percentages were considered and the results compared.The results, which were presented as Probability Density Functions (PDFs),indicate that the zones of low stiffness show high range of displacements andthat the increase in the percentage of the ore significantly affects the stability ofthe stopes.
|
|
