| 1. |
- Abarenkov, Kessy, et al.
(författare)
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Annotating public fungal ITS sequences from the built environment according to the MIxS-Built Environment standard – a report from a May 23-24, 2016 workshop (Gothenburg, Sweden)
- 2016
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Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 16, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Recent molecular studies have identified substantial fungal diversity in indoor environments. Fungi and fungal particles have been linked to a range of potentially unwanted effects in the built environment, including asthma, decay of building materials, and food spoilage. The study of the built mycobiome is hampered by a number of constraints, one of which is the poor state of the metadata annotation of fungal DNA sequences from the built environment in public databases. In order to enable precise interrogation of such data – for example, “retrieve all fungal sequences recovered from bathrooms” – a workshop was organized at the University of Gothenburg (May 23-24, 2016) to annotate public fungal barcode (ITS) sequences according to the MIxS-Built Environment annotation standard (http://gensc.org/mixs/). The 36 participants assembled a total of 45,488 data points from the published literature, including the addition of 8,430 instances of countries of collection from a total of 83 countries, 5,801 instances of building types, and 3,876 instances of surface-air contaminants. The results were implemented in the UNITE database for molecular identification of fungi (http://unite.ut.ee) and were shared with other online resources. Data obtained from human/animal pathogenic fungi will furthermore be verified on culture based metadata for subsequent inclusion in the ISHAM-ITS database (http://its.mycologylab.org).
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| 2. |
- Anderson, Dan, 1943, et al.
(författare)
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Approximate solution of a Thomas-Fermi model equation for bulk self-gravitating stellar objects in two dimensions
- 2017
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Ingår i: European journal of physics. - : Institute of Physics (IOP). - 0143-0807 .- 1361-6404. ; 38, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Direct variational methods are used to find simple approximate solutions of the Thomas–Fermi equations describing the properties of self-gravitating radially symmetric stellar objects both in the non-relativistic and ultra-relativistic cases. The approximate solutions are compared and shown to be in good agreement with exact and numerically obtained solutions.
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| 3. |
- Anderson, Dan, 1943, et al.
(författare)
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Introduction to direct variational and moment methods and an application to the Child-Langmuir law
- 2015
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Ingår i: European Journal of Physics. - : IOP Publishing. - 1361-6404 .- 0143-0807. ; 2015:36, s. 065032-
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Tidskriftsartikel (refereegranskat)abstract
- A short introduction is given of direct variational methods and its relation to Galerkin and moment methods, all flexible and powerful approaches for finding approximate solutions of difficult physical equations. A pedagogicalapplication of moment methods is given to the physically and technically important Child–Langmuir law in electron physics. The analysis is shown to provide simple, yet accurate, approximate solutions of the two-dimensionalproblem (a problem which does not allow an exact analytical solution)and illustrates the usefulness and the power of moment methods.
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| 4. |
- Anderson, Dan, 1943, et al.
(författare)
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The least uncomfortable journey from A to B
- 2016
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Ingår i: American Journal of Physics. - : American Association of Physics Teachers (AAPT). - 0002-9505 .- 1943-2909. ; 84:9, s. 690-695
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Tidskriftsartikel (refereegranskat)abstract
- A short introduction is given about direct variational methods and their relation to Galerkin and moment methods, all flexible and powerful approaches for finding approximate solutions to difficult physicalequations. An application of these methods is given in the form of the variational problem of minimizing the discomfort experienced during different journeys, between two fixed horizontal points while keeping the travel time constant. The analysis is shown to provide simple, yet accurate, approximate solutions of the problem and illustrates the usefulness and the power of direct variational and moment methods. It also demonstrates the problem of a priori assessing the accuracy of the approximate solutions and illustrates that the variational solution does not necessarily provide a more accurate solution than that obtained by moment methods.
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| 5. |
- Andersson, Roy, et al.
(författare)
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Total productive maintenance in support processes : an enabler for operation excellence
- 2015
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Ingår i: Total Quality Management and Business Excellence. - : Informa UK Limited. - 1478-3363 .- 1478-3371. ; 26:9-10, s. 1042-1055
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Tidskriftsartikel (refereegranskat)abstract
- In order to stay competitive in today's marketplace, it is vital to reduce activities that do not create value. Lean production has in the last decade been seen as a philosophy to reduce non-value time. The office environment often presents a major improvement opportunity to reduce non-value time. Lean contributes positively to business performance applied in a manufacturing context and is also suggested to do the same in a service context. The purpose of the paper is to analyse and determine how total productive maintenance (TPM) can be applied within the support process and to identify effects from an employee and business perspective. A case study has been performed and a qualitative research approach was selected. Empirical data were gathered by using semi-structured interviews at one case company, but from several teams that had applied TPM. The result was then used as an inductive approach to explore how TPM can be applied in a support process. To implement and apply TPM within an office context, it should be structured in three steps (i) define, (ii) implement and (iii) sustain. TPM should be conducted as a part of the ordinary day-to-day work. The planning and discussions connected to TPM can be included in regular daily departmental stand-up meetings' involving everybody. The work with 5S and maintenance should also be a part of the TPM structure, connecting it as a system and not as an isolated activity. TPM can create value from both a business and an employee perspective. In the employee perspective, TPM reduces the risk of missing/forgetting areas of responsibility and creates more involvement. In the business perspective, objectives such as cost and quality are improved, but TPM also enables the reduction of waste.
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| 6. |
- Asbjörnsson, Gauti, 1985, et al.
(författare)
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Modelling of Discrete Downtime in Continuous Crushing Operation
- 2015
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Ingår i: Computational Modelling 2015, MEI conference.
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Konferensbidrag (refereegranskat)abstract
- Crushing is a harsh process and production units are subjected to wear and failure over time which will reduce the overall performance of the plant. To achieve optimum process performance, both time dependant process dynamics and operating conditions should be taken into account.In this paper the aim is to create a framework for simulating the process from a more operational perspective to evaluate process performance and process optimum for different operational scenarios. The objective is to model and simulate the discrete phenomena that can cause the process to alter performance and implement it with dynamic process simulations. A method for combining discrete probability simulations with time-continuous simulations for process evaluation and optimization is presented. The proposed framework demonstrates a systematic approach to evaluate the process performance and locating optimum process configuration, for a given condition. The developed models can be used to optimize different aspects of the operation depending on the defined objective function and the system boundaries. Optimization of process throughput by manipulating configuration of both the grizzly and the crushers, as well as the time between calibrations has been illustrated in this paper. Adjusting the process continuously and calibrating it at the appropriate time can have major benefits when it comes to the process availability and utilization, increasing performance by 4.1-9.3 % in these cases. Evaluation of process robustness with regards to different maintenance strategies and process variation gave an indication of the process and unit performance under a long operating period. By combining discrete and dynamic simulation, a higher simulation fidelity can be achieved to provide a more operational perspective to the optimization and process analysis.
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| 7. |
- Atalar, Aras, 1985, et al.
(författare)
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Modeling Energy Consumption of Lock-Free Queue Implementations
- 2015
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Ingår i: 29th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2015, Hyderabad, India, 25-29 May. - : IEEE Computer Society. - 1530-2075. - 9781479986484 ; , s. 229-238
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Konferensbidrag (refereegranskat)abstract
- This paper considers the problem of modeling the energy behavior of lock-free concurrent queue data structures. Our main contribution is a way to model the energy behavior of lock-free queue implementations and parallel applications that use them. Focusing on steady state behavior we decompose energy behavior into throughput and power dissipation which can be modeled separately and later recombined into several useful metrics, such as energy per operation. Based on our models, instantiated from synthetic benchmark data, and using only a small amount of additional application specific information, energy and throughput predictions can be made for parallel applications that use the respective data structure implementation. To model throughput we propose a generic model for lock-free queue throughput behavior, based on a combination of the dequeuers' throughput and enqueuers' throughput. To model power dissipation we commonly split the contributions from the various computer components into static, activation and dynamic parts, where only the dynamic part depends on the actual instructions being executed. To instantiate the models a synthetic benchmark explores each queue implementation over the dimensions of processor frequency and number of threads. Finally, we show how to make predictions of application throughput and power dissipation for a parallel application using a lock-free queue requiring only a limited amount of information about the application work done between queue operations. Our case study on a Mandelbrot application shows convincing prediction results.
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| 8. |
- Bazooyar, Faranak, 1972, et al.
(författare)
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Computational studies of water and carbon dioxide interactions with cellobiose
- 2015
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Ingår i: Journal of Molecular Modeling. - : Springer Science and Business Media LLC. - 0948-5023 .- 1610-2940. ; 21:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- B3LYP/6-311++G** with dispersion correction (DFT-D) was used to study local and global minimum energy structures of water (H2O) or carbon dioxide (CO2) bonding with a pair of cellobiose molecules. The calculations showed that neither the H2O nor the CO2 prefer to be between the cellobiose molecules, and that the minimum energy structures occur when these molecules bond to the outer surface of the cellobiose pair. The calculations also showed that the low energy structures have a larger number of inter-cellobiose hydrogen bonds than the high energy structures. These results indicate that penetration of H2O or CO2 between adjacent cellobiose pairs, which would assist steam or supercritical CO2 (SC-CO2) explosion of cellulose, is not energetically favored. Comparison of the energies obtained with DFT-D and DFT (the same method but without dispersion correction) show that both hydrogen bonds and van der Waals interactions play an important role in cellobiose-cellobiose interactions.
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| 9. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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ADVANCED MATERIAL MODELLING IN CRUSHING PLANTS USING REAL TIME ALGORITHMS
- 2015
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Ingår i: Computational Modelling 2015, MEI conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In process control of crushing plants the traditional control is focused on stability control ofsingle machines and not on controlling material utilization. The reason for this is that the use ofmaterial property models is not that well known. The material models describe properties as e.g.capacity over time for a given product and this may depend on many parameters and dynamic effectsin the process. Due to this it is complicated to model and thus a methodology is needed to solve thisproblem. In this paper a novel method for modeling the current effect that the production units haveon the material presented. The paper presents a methodology how to use process data from SCADAsystem to analyze and suggest dynamic material model properties in real time.
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| 10. |
- Bengtsson, Magnus, 1973, et al.
(författare)
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Cost And Performance Optimization Of A Tertiary Crushing Stage
- 2015
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Ingår i: ESCC 2015 Conference. - Göteborg : Chalmers University of Technology. - 9789188041012
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Konferensbidrag (refereegranskat)abstract
- There is increasing demand to optimise performance and profit of crushing plants. Research in this area has resulted in the development of numerous optimisation tools, and resent research has shown that the quality aspects of production have great influence on the optimisation results. The quality, cost, profit 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 use the parameters cost, profit, capacity and quality in order to perform a multi objective optimization of a crushing plant is presented. As an example a tertiary crushing stage consistent of a cone crusher and a vertical shaft impact crusher (VSI) is used as base for the designed objective function. The process has a given set of constraints that represents the conditions normal in these type of crushing 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. The next step in the optimization shows how a strategy for relaxing constraint can increase overall productivity and still reach certain product properties. The conclusions made in this work are that multi objective optimization is essential when optimizing crushing plant production against multiple objectives. Relaxation of constraints can increase the overall performance of the crushing plant.
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