| 41. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Modelling of output and power consumption in vertical shaft impact crushers
- 2008
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Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 88:1-2, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- The vertical shaft impact (VSI) crusher is a commonly-used machine in aggregate production. A comprehensive understanding of the physical phenomena that influence the power consumption and the particle output of the device are essential to enable development of protocols that minimize energy consumption during rock crushing.While natural gravel has traditionally been the main choice of material for Swedish concrete manufacturers, the number of deposits is limited due to its role as a fresh water filter. It is therefore essential to achieve a product size distribution of aggregate that is on the same order as that of natural gravel to enable its use in concrete production.This work aims to present a model that predicts capacity, power and particle size distribution in a VSI crusher.
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| 42. |
- Bengtsson, Magnus, 1973
(författare)
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Quality-Driven Production of Aggregates in Crushing Plants
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aggregate quality is of great importance, and in this context it is essential to understand how various process parameters influence the product quality characteristics. Thus, there is a need for aggregate producers to improve their process knowledge.Research has led to an improved understanding of how different process parameters affect the outcomes of specific comminution processes. In aggregate production, breakage models are one example of such a research result. These models have been refined over the years. The breakage models that have been presented to date can accurately predict the size distribution of aggregates. On the other hand, they cannot normally predict any other material characteristics such as shape and strength. This thesis outlines the research to date, which has focused on a frequently discussed quality parameter, namely the shape of the product. Knowledge of various methodologies is required to measure this parameter. A novel method for measuring the shape of fine aggregates is presented. The rheology test, the methodology of which was originally based on a New Zealand standard, can be correlated with other data to measure particle shape in accordance with the F-aspect method. The correlation between these methods is very good, and since the rheology test is easy to use, it is suitable for a quarry or a basic test facility.The cone crusher is the most commonly used tertiary stage crusher today. One of its great advantages is that it produces a relatively low amount of fines. However, it only produces acceptable particle shapes for certain fraction sizes. The vertical shaft impact crusher (VSI) creates particles of a very satisfactory shape across all fractions, including fine aggregate, as confirmed by studies using the aforementioned rheology test.This thesis presents two models for predicting shape in crushed aggregate from a cone crusher. The first model is empirical, and my conclusion is that there are four dominating parameters affecting shape: the average feed size, the closed side setting (CSS), throw and eccentric speed. To further investigate how compressive breakage affects particle shape, an inter-particle breakage model is introduced. This model simulates a specific crushing stage inside the crusher. Simulation results show that the outcome from a crushing event can be predicted with good accuracy. A VSI model for describing particle size and shape is presented in this work. It is proposed that the dominating breakage mechanism in a VSI equipped with a rock box is of abrasive character. Abrasive breakage can appropriately shape all particle sizes, assuming the crusher is operated at a proper velocity.The empirical cone crusher model and the VSI models are combined in a mathematical simulation in order to determine how a crushing plant should be operated to maximise both yield and aggregate quality. The results show that there exists a set of rules to determine the crusher and screen settings that will achieve the best performance in terms of product yield and quality requirements.
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| 43. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Size and shape simulation in a tertiary crushing stage, a multi objective perspective
- 2015
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 77, s. 72-77
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing demand to optimise yield and increase capacity of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and recent research has shown that the quality aspects of production have great influence on the optimisation results. The quality and capacity of a product is influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimisation software.In this paper, a novel approach to analyse the parameters product capacity and quality is presented. As an example a cone crusher and a vertical shaft impact crusher (VSI) is simulated in a tertiary stage. The simulation shows how capacity and product quality for a range of products will be affected when a parameter is changed. The paper also shows how wear will affect product capacity and quality.
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| 44. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Towards dynamical profit optimization of comminution circuits
- 2017
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 103, s. 14-24
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing demand to optimize performance and profit of comminution circuits. Research in this area has resulted in the development of numerous optimization tools, and recent research has shown that the quality aspects of the production have a great influence on the optimization results. The quality, cost, profit and capacity of a product are influenced by several parameters, and in order to control all of these parameters it is necessary to use some sort of optimization algorithm. In this paper, a novel approach to apply e.g. cost, revenue, capacity and quality in order to perform a multi objective optimization with the ability to handle dynamic variations of a comminution is presented. The problem with optimizations in general is that the objective function used for optimization is reduced in complexity in order to save computational time. In a comminution process performance varies with time and in order to perform a correct optimization the objective function used must be able to handle this type of dynamic behavior. The process has a given set of constraints that represents the conditions normal in these type of comminution applications. The first step in this paper is to identify if the range of the constraints can cause undesirable production costs when reaching for a given product property. In this step a dynamic response model is described that will be able to address the difficulties with optimizing dynamic systems. The next step in the optimization is the definition of the multi-objective optimization formulation including constraints for the optimization. Evaluating the result of the optimization in combination with a strategy for relaxing constraint can show how to increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing a comminution circuit against multiple objectives.
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| 45. |
- Berg, Marie, 1955, et al.
(författare)
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Room4Birth - the effect of an adaptable birthing room on labour and birth outcomes for nulliparous women at term with spontaneous labour start: study protocol for a randomised controlled superiority trial in Sweden
- 2019
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Ingår i: Trials. - : Springer Science and Business Media LLC. - 1745-6215 .- 1745-6215. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: An important prerequisite for optimal healthcare is a secure, safe and comfortable environment. There is little research on how the physical design of birthing rooms affects labour, birth, childbirth experiences and birthing costs. This protocol outlines the design of a randomised controlled superiority trial (RCT) measuring and comparing effects and experiences of two types of birthing rooms, conducted in one labour ward in Sweden. METHODS/DESIGN: Following ethics approval, a study design was developed and tested for feasibility in a pilot study, which led to some important improvements for conducting the study. The main RCT started January 2019 and includes nulliparous women presenting to the labour ward in active, spontaneous labour and who understand either Swedish, Arabic, Somali or English. Those who consent are randomised on a 1:1 ratio to receive care either in a regular room (control group) or in a newly built birthing room designed with a person-centred approach and physical aspects (such as light, silencer, media installation offering programmed nature scenes with sound, bathtub, birth support tools) that are changeable according to a woman's wishes (intervention group). The primary efficacy endpoint is a composite score of four outcomes: no use of oxytocin for augmentation of labour; spontaneous vaginal births (i.e. no vaginal instrumental birth or caesarean section); normal postpartum blood loss (i.e. bleeding < 1000 ml); and a positive overall childbirth experience (7-10 on a scale of 1-10). To detect a difference in the composite score of 8% between the groups we need 1274 study participants (power of 80% with significance level 0.05). Secondary outcomes include: the four variables in the primary outcome; other physical outcomes of labour and birth; women's self-reported experiences (the birthing room, childbirth, fear of childbirth, health-related quality of life); and measurement of costs in relation to the hospital stay for mother and neonate. Additionally, an ethnographic study with participant observations will be conducted in both types of birthing rooms. DISCUSSION: The findings aim to guide the design of birthing rooms that contribute to optimal quality of hospital-based maternity care. TRIAL REGISTRATION: ClinicalTrials.gov NCT03948815. Registered 13 May 2019-retrospectively registered.
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| 46. |
- Berglin, Lena, et al.
(författare)
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Smart Textiles : what for and why?
- 2005
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Ingår i: Nordic Textile Journal. - : University College of Borås. The Swedish School of Textiles. - 1404-2487.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 47. |
- Bergman, Bo, 1943, et al.
(författare)
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Ständig förbättring och dess rötter i pragmatismen
- 2007
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Ingår i: Elg, M., Gautherau, V., Witell, L. (2007). Att Lyckas med Förbättringsarbete - Förbättra, Förändra, Förnya. - Lund : Studentlitteratur AB.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 48. |
- Bhadani, Kanishk, 1991, et al.
(författare)
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Application of Multi-Disciplinary Optimization Architectures in Mineral Processing Simulations
- 2018
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Ingår i: 11th International Comminution Symposium. - 9781510883789
-
Konferensbidrag (refereegranskat)abstract
- Optimization is a pivotal point in distinguishing the competitiveness between industries that are developing, designing and operating products and processes. Mineral processing is an industry which operates various sub-processes and produces one or several products. The sub-processes involved are dynamic in nature and differs in discipline of operation. These dynamic sub-processes are sequentially integrated forming a mineral processing system. Currently, the developed simulations for the mineral processing systems have the potential to be used to design, operate and control mineral processing plants to an increased extent, but need broader optimization strategies to integrate multiple sub-processes involved. The scope of this research is to demonstrate application of multi-disciplinary optimization (MDO) architectures into a mineral processing simulation. A case study consisting of two sub-processes of comminution and classification circuits to produce aggregate products is used to demonstrate the application of MDO architectures. The MDO architectures are compared based on problem formulation, computational resources required and validity of the results. The optimization results using MDO architectures can be used to illustrate trade-offs between different sub-processes within the considered scope. The application of MDO architectures can facilitate the linking mathematical models of various disciplines such as comminution, and liberation in mineral processing simulation.
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| 49. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
Application of Structural Optimization for an Early Stage Product Development
- 2017
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Ingår i: NAFEMS World Congress 2017, A World of Engineering Simulation, Stockholm, Sweden. - 9781910643372 ; , s. 13-
-
Konferensbidrag (refereegranskat)abstract
- In today’s automotive industry there is a growing demand for more fuel efficient vehicles and reduced development times. These trends are driven by stricter environmental regulations, a growing environmental awareness, and increasing technological development and competitiveness. Finding an optimized and balanced component that fulfils the requirements in an early phase of the product development is a prerequisite for enabling more competitive lead times, costs, weights and minimizing the risk for late design changes. The aim with this paper is to show a process capturing CAE driven development for an early stage development of components in a complex system. The process utilizes structural optimization techniques to generate knowledge, optimize and balance packaging volumes of adjacent components in complex systems. The paper also highlight the organizational challenges and technical challenges involving the use of structural optimization for realizing the process completely. The paper will illustrate the simultaneous use of topology and shape optimization to generate knowledge for the optimized design volume for multiple adjacent components linked together. The linking of the multiple component is carried out using morphing technique and the design space between the multiple components is dynamic in nature during simulation. The mesh in one component is allowed to change according to the mesh of the other component during the simulation. The result from the simultaneous topology and shape optimization simulation generates the knowledge if it is feasible to change design volume to meet the weight and performance targets. The process also indicates how much performance increase is possible if the design volume is allowed to change and thus generating a trade-off between the components performance.The new process has a potential to be extended to other conflicting scenarios in adjacent components which exists in early stages of development process especially, cases involving conflicting structural requirements in various industries.
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| 50. |
- Bhadani, Kanishk, 1991, et al.
(författare)
-
State of the Art in Application of Optimization Theory in Minerals Processing
- 2017
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Ingår i: European Symposium on Comminution and Classification, Izmir, Turkey.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There has been continuous development going over the past 40 years related to the creation of models and simulation techniques to predict the behaviour of equipment and processes in minerals processing. At the same time, application of optimization theory into such modelling and simulation schemes has been applied to generate knowledge to improved performances of the equipment and processes.Different optimization techniques have been applied to design and configure different equipment and processes, yet there are no well-established formulations to reproduce the results. The research is scattered and focused on the need and application of the specific equipment or process not utilizing the optimization’s full potential.The aim of this paper is to highlight the trends in development of optimization schemes in minerals processing. By understanding the state of the art in application of optimization theory into mineral processing will further pave the possibility to develop utility in this field. The paper presents two classification schemes: State of Development Stage and State of Application Area as a basis to classify research within optimization related to mineral processing. In order to make smart and strategic decisions in minerals processing operations, it is required to further develop optimization techniques into modelling and simulation schemes to extract the relevant information. The classification schemes can be useful in defining the future focus area for research and development.
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