| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Wang, Hong, et al.
(författare)
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Ambient Electrosynthesis of Ammonia : Electrode Porosity and Composition Engineering
- 2018
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 57:38, s. 12360-12364
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia, a key precursor for fertilizer production, convenient hydrogen carrier, and emerging clean fuel, plays a pivotal role in sustaining life on Earth. Currently, the main route for NH3 synthesis is by the heterogeneous catalytic Haber-Bosch process (N-2+ 3H(2) -> 2NH(3)), which proceeds under extreme conditions of temperature and pressure with a very large carbon footprint. Herein we report that a pristine nitrogen-doped nanoporous graphitic carbon membrane (NCM) can electrochemically convert N-2 into NH3 in an acidic aqueous solution under ambient conditions. The Faradaic efficiency and rate of production of NH3 on the NCM electrode reach 5.2% and 0.08 gm(-2) h(-1), respectively. Functionalization of the NCM with Au nanoparticles dramatically enhances these performance metrics to 22% and 0.36 gm(-2) h(-1), respectively. As this system offers the potential to be scaled to industrial levels it is highly likely that it might displace the century-old Haber-Bosch process.
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| 4. |
- Bai, Sai, et al.
(författare)
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Planar perovskite solar cells with long-term stability using ionic liquid additives
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 571:7764, s. 245-250
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Tidskriftsartikel (refereegranskat)abstract
- Solar cells based on metal halide perovskites are one of the most promising photovoltaic technologies(1-4). Over the past few years, the long-term operational stability of such devices has been greatly improved by tuning the composition of the perovskites(5-9), optimizing the interfaces within the device structures(10-13), and using new encapsulation techniques(14,15). However, further improvements are required in order to deliver a longer-lasting technology. Ion migration in the perovskite active layer-especially under illumination and heat-is arguably the most difficult aspect to mitigate(16-18). Here we incorporate ionic liquids into the perovskite film and thence into positive-intrinsic-negative photovoltaic devices, increasing the device efficiency and markedly improving the long-term device stability. Specifically, we observe a degradation in performance of only around five per cent for the most stable encapsulated device under continuous simulated full-spectrum sunlight for more than 1,800 hours at 70 to 75 degrees Celsius, and estimate that the time required for the device to drop to eighty per cent of its peak performance is about 5,200 hours. Our demonstration of long-term operational, stable solar cells under intense conditions is a key step towards a reliable perovskite photovoltaic technology.
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| 5. |
- Bai, Sai, et al.
(författare)
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Reproducible Planar Heterojunction Solar Cells Based on One-Step Solution-Processed Methylammonium Lead Halide Perovskites
- 2017
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Ingår i: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 29:1, s. 462-473
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have been demonstrated as one of the most promising materials for low-cost and high-performance photovoltaic applications. However, due to the susceptible crystallization process of perovskite films on planar substrates and the high sensitivity of the physical and optoelectronic nature of the internal interfaces within the devices, researchers in different laboratories still experience poor reproducibility in fabricating efficient perovskite solar cells with planar heterojunction device structures. In this method paper, we present detailed information on the reagents, equipment, and procedures for the fabrication of planar perovskite solar cells in both "regular" n-i-p and "inverted" p-i-n architectures based on one-step solution-processed methylammonium lead triiodide (MAPbI(3)) perovskite films. We discuss key parameters affecting the crystallization of perovskite and the device interfaces. This method paper will provide a guideline for the reproducible fabrication of planar heterojunction solar cells based on MAPbI3 perovskite films. We believe that the shared experience on MA-based perovskite films and planar solar cells will be also useful for the optimization process of perovskites with varied compositions, and other emerging perovskite-based optoelectronic devices.
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| 6. |
- Shao, Yue, et al.
(författare)
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All-Poly(ionic liquid) Membrane-Derived Porous Carbon Membranes : Scalable Synthesis and Application for Photothermal Conversion in Seawater Desalination
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:11, s. 11704-11710
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we introduce a straightforward, scalable, and technologically relevant strategy to manufacture charged porous polymer membranes (CPMs) in a controllable manner. The pore sizes and porous architectures of CPMs are well-controlled by rational choice of anions in poly(ionic liquid)s (PILs). Continuously, heteroatom-doped hierarchically porous carbon membrane (HCMs) can be readily fabricated via morphology-maintaining carbonization of as-prepared CPMs. These HCMs, as photothermal membranes, exhibited excellent performance for solar seawater desalination, representing a promising strategy to construct advanced functional nanomaterials for portable water production technologies.
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| 7. |
- Berglund, Jonatan, 1983, et al.
(författare)
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Production system geometry assurance using 3D imaging
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 44, s. 132-137
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Konferensbidrag (refereegranskat)abstract
- Production systems evolve to accommodate new and redesigned products. These changes are planned offline in virtual tools, to reduce disturbances on ongoing production. Offline planning requires virtual models that correctly represent reality. Most models are "as-designed" and suffer from geometrical errors stemming from deployment alterations. Such errors are often discovered late in the next change process or during installation, making corrections expensive. Having geometry assured production systems and models eliminate one source of error during the production system change process. This paper evaluates 3D imaging and the C2M (cloud-to-mesh) algorithm for assessing the validity of virtual production system models.
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| 8. |
- Birney, Ewan, et al.
(författare)
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Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
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Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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| 9. |
- Eriksson, Kristina M., 1976-, et al.
(författare)
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Conceptual framework of scheduling applying discrete event simulation as an environment for deep reinforcement learning
- 2022
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271 .- 2212-8271. ; 107, s. 955-960
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Tidskriftsartikel (refereegranskat)abstract
- Increased environmental awareness is driving the manufacturing industry towards novel ways of energy reduction to become sustainable yet stay competitive. Climate and enviromental challenges put high priority on incorporating aspects of sustainability into both strategic and operational levels, such as production scheduling, in the manufacturing industry. Considering energy as a parameter when planning makes an already existing highly complex task of production scheduling even more multifaceted. The focus in this study is on inverse scheduling, defined as the problem of finding the number of jobs and duration times to meet a fixed input capacity. The purpose of this study was to investigate how scheduling can be formulated, within the environment of discrete event simulation coupled with reinforcement learning, to meet production demands while simultaneously minimize makespan and reduce energy. The study applied the method of modeling a production robot cell with its uncertainties, using discrete event simulation combined with deep reinforcement learning and trained agents. The researched scheduling approach derived solutions that take into consideration the performance measures of energy use. The method was applied and tested in a simulation environment with data from a real robot production cell. The study revealed opportunities for novel approaches of studying and reducing energy in the manufacturing industry. Results demonstrated a move towards a more holistic approach for production scheduling, which includes energy usage, that can aid decision-making and facilitate increased sustainability in production. We propose a conceptual framework for scheduling for minimizing energy use applying discrete event simulation as an environment for deep reinforcement learning.
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| 10. |
- Gong, Liang, 1985, et al.
(författare)
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Development of virtual reality support to factory layout planning
- 2019
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Ingår i: International Journal on Interactive Design and Manufacturing. - : Springer Science and Business Media LLC. - 1955-2505 .- 1955-2513. ; 13:3, s. 935-945
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Tidskriftsartikel (refereegranskat)abstract
- Virtual reality (VR) technology has become ever mature today with affordable and yet powerful hardware. In the manufacturing industry, there is a growing interest of adopting VR to improve existing work procedures. Factory layout planning (FLP) is a long standing area in production engineering that sees great potentials of VR integration. Virtual reality supported layout planning (VLP) is gaining wider attention in research and practice as the virtual environment allows designers to test out “what if” scenarios in relative ease. However, previous research of VLP mostly focus on general layout planning but not the detailed level planning. Also, it is reported that the virtual modeling process is time-consuming and costly. In this study, we propose a point cloud based virtual factory modelling approach for the VLP tasks. It incorporates point cloud representation of physical environment with CAD data to model the virtual factory with the aims of simplifying the modelling process and improving decision-making for the VLP tasks. The proposed approach is exemplified and refined through three industrial cases. The implementations and results of the cases are highlighted and discussed in details. At the end, a general guidance for VLP is extracted and presented for future point cloud based VR support in FLP tasks.
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| 11. |
- Gong, Liang, 1985, et al.
(författare)
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Improving manufacturing process change by 3D visualization support: A pilot study on truck production
- 2016
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 57, s. 298-302
-
Konferensbidrag (refereegranskat)abstract
- In the global market, customer demands changes rapidly. Manufacturing companies need to meet the demands to keep competitive. Therefore, manufacturing processes constantly need to be changed. The process change is challenging because it involves different actors across the company, especially for international companies that have globally distributed operations.Manufacturing process change is carried out by production engineers and needs to consider the needs and requirement of all actors in the manufacturing system. To this end, guidelines for manufacturing system design and cross-functional team meetings for concept design assessmentare utilized. While the meeting takes place, such meetings require resources to be available in parallel and advanced planning to come to fruition. Thus making the concept design iteration loop considerably longer if inputs are to be collected frequently.This paper presents an approach that utilizes a collaborative tool developed in Unity. It integrates 3D scanned factory data with proposed process changes to provide sufficient context to every stakeholders involved. Thus, to facilitate better understanding and communication of the ongoing changes. It will improve every process change on its design, implementation, and future maintenance. The challenges of implementation and evaluation of the collaborative tool are discussed.
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| 12. |
- Grubbström, Robert W., et al.
(författare)
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A stochastic model of multi-level/multi-stage capacity-constrained production–inventory systems
- 2003
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Ingår i: International Journal of Production Economics. - 0925-5273 .- 1873-7579. ; 81-82, s. 483-494
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Tidskriftsartikel (refereegranskat)abstract
- A great deal of research has been done on capacity-constrained production–inventory systems, most of which concerns deterministic demand situations and single-product systems. In this paper we present a model of a multi-level capacity-constrained system when external demand is stochastic. Unlike the traditional total cost objective, adopted in the vast majority of capacity-constrained production–inventory models, the (expected) Net Present Value is here used as the objective function. Dynamic programming is chosen as the solution procedure. Numerical examples are given to explain the model and to illustrate features when changing available capacity.The Laplace transform together with input–output analysis are employed as tools to construct the model. This approach has been used in previous research to formulate a theoretical base for Material Requirements Planning (MRP) systems.The paper provides a further argument for the use of transforms in combination with matrix representations of product structures and capacity requirements, and it extends previous theory in the direction of capacity considerations combined with uncertainty in external demand. Dynamic programming is also shown to be a practical method for the multi-stage optimisation involved.The numerical examples further illustrate, for instance, the natural propensity for subordinate items to be lot sized in a more lumpy way than their parents, and also how the marginal benefit of capacity increments follows the law of diminishing returns. Also comparisons are made with solutions from the deterministic equivalence model, using average demand as a proxy.
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| 13. |
- Grubbström, Robert W., et al.
(författare)
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Ideas for introducing capacity planning into MRP applying input-output analysis and Laplace transforms
- 2001
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Ingår i: Promet - Traffic - Traffico. - 0353-5320. ; 13:6, s. 371-377
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Tidskriftsartikel (refereegranskat)abstract
- Laplace transform and input-output analysis have been used to formulate a theoretical basis for Material Requirements Planning (MRP) system. In this paper, we will formulate a model for capacity-constrained production-inventory system applying Laplace transform and input-output analysis, which is different from the classical method of handling the capacity problem.
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| 14. |
- Grubbström, Robert W., et al.
(författare)
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Introducing capacity limitations into multi-level, multi-stage production-inventory systems applying the input-output/Laplace transform approach
- 2000
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 38:17, s. 4227-4234
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Tidskriftsartikel (refereegranskat)abstract
- The Laplace transform and Input-Output Analysis have been used to formulate a theoretical basis for Material Requirements Planning (MRP). In this paper, as a first step to incorporating capacity limitations into this theory, we introduce alternative formulations of a model for capacity-constrained production-inventory systems in a deterministic environment applying the same approach. We focus our attention on the way in which the balance equations constraining the system need to be modified. A numerical example is given to explain the model.
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| 15. |
- Grubbström, Robert W., et al.
(författare)
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Modelling capacity-constrained production-inventory systems : a review
- 2000
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Ingår i: Proceedings of the 11th International Working Seminar on Production Economics, Vol. 1. ; , s. 99-105
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a survey of the current literature on capacity-constrained production-inventory problems in the MRP context. Research work within both the deterministic and stochastic environments are summarised. Certain aspects related to model formulation are also discussed. Our aim is to give a generalunderstanding of the capacitated lot-sizing problem rather than a comprehensive literature study. The literature covered is mostly since 1980. A basic aim is also to create a background to generalisations of theoretical developments on material requirements planning applying input-output analysis and Laplace transforms.
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| 16. |
- Jiang, Zhiping, et al.
(författare)
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Fine tuning the hydrophobicity of counter-anions to tailor pore size in porous all-poly(ionic liquid) membranes
- 2019
-
Ingår i: Polymer international. - : Wiley. - 0959-8103 .- 1097-0126. ; 68:9, s. 1566-1569
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Tidskriftsartikel (refereegranskat)abstract
- Charged porous polymer membranes (CPMs) emerging as a multifunctional platform for diverse applications in chemistry, materials science and biomedicine have been attracting widespread attention. Fabrication of CPMs in a controllable manner is of particular significance for optimizing their function and maximizing practical values. Herein, we report the fabrication of CPMs exclusively from poly(ionic liquid)s (PILs), and their pore size and wettability were precisely tailored by rational choice of counter-anions. Specifically, a stepwise subtle increase in hydrophobicity of the counter-anions by extending the length of fluorinated alkyl substituents, i.e. from bis(trifluoromethane sulfonyl)imide to bis(pentafluoroethane sulfonyl)imide and bis(heptafluoropropane sulfonyl)imide, decreased the average pore size gradually from 1546 to 157 and 77 nm, respectively. Meanwhile, the corresponding water contact angles increased from 90 degrees to 102 degrees and 120 degrees. The sensitive control over the porous architectures and surface wettability of CPMs by systematic variation of anion hydrophobicity provides solid proof of the impact of PIL anions on CPM structure.
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| 17. |
- Liu, Jiewei, et al.
(författare)
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Identification and Mitigation of a Critical Interfacial Instability in Perovskite Solar Cells Employing Copper Thiocyanate Hole-Transporter
- 2016
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Ingår i: ADVANCED MATERIALS INTERFACES. - : WILEY. - 2196-7350. ; 3:22
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have emerged as one of the most promising materials for photovoltaics (PVs), with power conversion efficiency of over 22% already demonstrated. In order to compete with traditional crystalline silicon PV, cost and stability are equally important issues that need to be considered besides efficiency. Copper thiocyanate (CuSCN) is an interesting candidate to be used as an inexpensive, thermally stable p-type charge conducting material in perovskite solar cells. Here, we report 13% efficient perovskite solar cells employing CuSCN as the hole-transport material. We compare the stability of cells employing CuSCN with those employing the archetypical organic hole-transporter 2,2 ,7,7 -Tetrakis (N,N-di-p-methoxyphenyl-amine) 9,9-Spirobifluorene (Spiro-OMeTAD), under elevated temperature in ambient atmosphere. Surprisingly, we find that the devices employing CuSCN degrade faster under elevated temperatures than the devices employing SpiroOMeTAD. We discover that an interfacial degradation mechanism occurs at the heterojunction between the perovskite absorber and the CuSCN, even in a dry nitrogen atmosphere, identifying the presence of a critical instability. Interestingly, with the additional coating of the completed cells with a thin film of insulating poly(methyl methacrylate) (PMMA), functioning as a rudimentary "on-cell" encapsulation, we significantly alleviate this issue and deliver efficient perovskite solar cells which survive for more than 1000 hours at 85 degrees C in air with only 25% degradation in performance. Beyond identifying a critical area to address in order to enable CuSCN to be useful for long term operation in perovskite solar cells, our findings indicate that the role of the "encapsulant" is to both keep the environment out, and keep degradation products within the cell.
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| 18. |
- Rexfelt, Oskar, 1975, et al.
(författare)
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Detailed specification and design specification for optimised layout, passenger flow and dwell time including new and attractive front, D 2.1.3.a in the project European Bus System of the Future
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In D2.1.3.a, simulation models are built for different bus design in order to find a optimal bus layout in terms of dwell time and passenger flow. The simulation result shows that layout 4 is the optimal one compared to other layouts. The main features of layout 4 are centre driver position and short front overhang, double doors with large door blade and flexible seat type in front car. It is also shown that dwell time can be reduced when ticket machines are positioned far away from the door (on the opposite side of the aisle), compared to the results when the ticket machines are positioned near by the door.Physical bus mockups are built in order to evaluate how different bus layouts affect dwell times and passengers’ experiences. It shows that the addition of the 4th door is positive. The experiment allowing passengers to only enter through the front door, however, increases dwell times.
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| 19. |
- Sullivan, Patrick F., et al.
(författare)
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Leveraging base-pair mammalian constraint to understand genetic variation and human disease
- 2023
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 380:6643, s. 367-
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Tidskriftsartikel (refereegranskat)abstract
- Thousands of genomic regions have been associated with heritable human diseases, but attempts to elucidate biological mechanisms are impeded by an inability to discern which genomic positions are functionally important. Evolutionary constraint is a powerful predictor of function, agnostic to cell type or disease mechanism. Single-base phyloP scores from 240 mammals identified 3.3% of the human genome as significantly constrained and likely functional. We compared phyloP scores to genome annotation, association studies, copy-number variation, clinical genetics findings, and cancer data. Constrained positions are enriched for variants that explain common disease heritability more than other functional annotations. Our results improve variant annotation but also highlight that the regulatory landscape of the human genome still needs to be further explored and linked to disease.
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| 20. |
- Thomay, Christian, et al.
(författare)
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Towards Adaptive Quality Assurance in Industrial Applications
- 2022
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Ingår i: Proceedings of the IEEE/IFIP Network Operations and Management Symposium 2022. - : IEEE. - 9781665406024 - 9781665406017
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Konferensbidrag (refereegranskat)abstract
- We propose the AQUILA framework (Adaptive Quality Assurance in Industrial Applications), a concept for digitalization in Industry 4.0 to support the entire industrial manufacturing chain, laying the groundwork for adaptive quality assurance in times of disrupted supply chains and, due to the COVID-19 pandemic, restricted travel possibilities. To that end, our proposed framework allows for the definition and description of industrial processes, quality assurance and testing protocols, and training scenarios in a comprehensive notation based on BPMN, and supports users in task execution, documentation, and evaluation by providing smart glass-based HCI with eye tracking technology, delivering a combination of process documentation, context-sensitive AR visualization, gaze-based interaction schemes, and remote maintenance and assistance functionality.
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| 21. |
- Wang, Di, et al.
(författare)
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Soil water infiltration characteristics of reforested areas in the paleo-periglacial eastern Liaoning mountainous regions, China
- 2024
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Ingår i: Catena. - 0341-8162. ; 234
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Tidskriftsartikel (refereegranskat)abstract
- Plantation forests (PF) and natural secondary forests (NSF) are the primary reforestation approaches. The establishment of PF can affect forest hydrological processes by changing soil structure. To date, few studies have focused on these changes and the effects on hydrological processes for the paleo-periglacial landform. To reveal reforestation approaches effects on water infiltration, including soil water infiltration capacity, retention capacity, and waterflow path pattern, we conducted field dye-tracer investigations with rainfall and laboratory infiltration experiments for the paleo-periglacial landform of eastern Liaoning mountains, China. The results showed that (1) Soil physical properties (including total porosity (TP), capillary porosity (CP), non-capillary porosity (NCP), initial soil water content (IWC), field water capacity (FWC)) and root abundance (RA) decreased with soil depth in both PF and NSF, while the soil bulk density (BD) and distribution of gravel content showed opposite changes. (2) Establishment of PF reduced the infiltration capacity and water retention capacity in the 0–20 cm layer, but enhanced the water retention capacity in 20–30 cm layer. Low IWC was conducive to increase soil water content (SWC) after infiltration. (3) Infiltration capacity parameters (including saturated hydraulic conductivity (Ks), SWC, difference between SWC and IWC (SWC–IWC), dye coverage ratio (DC)) were significantly correlated with BD, TP, CP, NCP, FWC, and fine roots RA (P < 0.05). Better connectivity gravels were more conducive to water infiltration. (4) Preferential flow was the main infiltration type, but with different waterflow paths pattern, with the 'funnel', 'finger' shape for PF, NSF, respectively. Increasing infiltration could increase flow path connectivity. Our findings show that soil physical properties, roots, and gravel occurrence affected soil infiltration, and different reforestation approaches had varying impacts on soil infiltration, water redistribution, transportation, and storage of surface and groundwater, improving the understanding of ecohydrological processes and effects of water resources management in forest ecosystems of paleo-periglacial landform.
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| 22. |
- Wang, Qing-Guo, et al.
(författare)
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Guaranteed dominant pole placement with PID controllers
- 2009
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Ingår i: Journal of Process Control. - : Elsevier BV. - 1873-2771 .- 0959-1524. ; 19:2, s. 349-352
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Tidskriftsartikel (refereegranskat)abstract
- Pole placement is a well-established design method for linear control systems. Note however that with an output feedback controller of low-order such as the PID controller one cannot achieve arbitrary pole placement for a high-order or delay system, and then partially or hopefully, dominant pole placement becomes the only choice. To the best of the authors' knowledge, no method is available in the literature to guarantee dominance of the assigned poles in the above case. This paper proposes two simple and easy methods which can guarantee the dominance of the two assigned poles for PID control systems. They are based on root locus and Nyquist plot respectively. If a solution exists, the parametrization of all the solutions is explicitly given. Examples are provided for illustration. (C) 2008 Elsevier Ltd. All rights reserved.
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| 23. |
- Wang, Zhiping
(författare)
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Acute cytokine responses to inhaled swine confinement building dust
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Inhalation of swine house dust (swine dust) may cause an acute inflammatory reaction Organic Dust Toxic Syndrome (ODTS). The reaction does not require sensitisation and is associated with airway inflammation, general symptoms, and slight spirometric changes. The agents and causing this reaction are not known. The purpose of this study was to investigate the release of pro-inflammatory cytokines in the airways and peripheral blood following acute exposure to swine dust, the correlation between markers for microbial contaminants in the dust, cytokine responses and health effects, and the release of those cytokines from an epithelial cell line (EP) and from human alveolar macrophages (AM) stimulated by swine dust and LPS. Healthy subjects, previously unengaged in farm work were exposed to swine dust for 3-4 hours. Interleukin (IL)-6,IL-I receptor antagonist(ra) and tumour necrosis factor (TNF)-a in serum, and IL-Ib in peripheral blood mononuclear cell (PBMC)were measured prior to and rear to exposure. IL-Ia, IL-IB, IL-6 and TNF-a were also measured in nasal lavage (NAL) fluid and bronchoalveolar lavage (BAL) before and after exposure. The time curve were done for IL-6, TNF-a and IL-IB. The mass of inhaled dust, the endotoxin concentration and two markers (muramic acid is a marker for total peptidoglycan content and 3 -(OH)-fatty acid is a marker for total lipopolysaccharide content.) for microbial exposure were quantified. Spirometry and a methacholine bronchial challenge were performed before and 7h after exposure to swine dust. Granulocytes, monocytes, and Iymphocytes were measured in blood with flow cytometry. NAL, BAL and PBMC cells were measured with colour stain. The oral temperature and general symptoms were recorded. Exposure to swine dust caused fever, headache, malaise, increased bronchial responsiveness, and a slight decrease in FEVI and VC. IL-Ira, IL-6 and TNF-a increased significantly in serum, IL- IB increased significantly in PBMC and plasma, IL- I, IL-6 and TNF-a increased significantly in BAL and NAL fluids. There was a marked influx of inflammatory cells, especially, of granulocytes. In peripheral blood, TNF-a, IL-6 and IL-IB increased and peaked during 3-5h, 5-7h and 3-7h respectively, after the start of exposure. The leukocytes doubled and monocytes increased slightly 6-8h after exposure. Endotoxin, muramic acid, and 3-OH fatty acid correlated significantly with increase in serum IL-6. Inhalable dust correlated with increase in serum IL-Ira, and endotoxin correlated with increase IL-IB in PBMC. Endotoxin and 3-OH fatty acids also correlated significantly with the IL-6 increase in BAL. Bacterial markers showed better correlation with IL 6 changes than total dust concentrations. LPS correlated with symptoms and with lung function changes. Peptidoglycan correlated with increase in blood granulocytes and body temperature. Swine dust caused a dose-dependent increase of IL-IB, IL-6 and TNF-a in AM. No increase of IL-IB or TNF-a, but a clear increase in IL-6 was found in EP. LPS caused a clear increase in all three cytokines in AM, but none of cytokines in EP. In conclusion, acute inhalation of dust contaminated with bacterial debris increased the concentration of pro-inflammatory cytokines in BAL, NAL, PBMC and peripheral blood. The changes in cytokines and inflammatory parameters correlated better with markers of bacterial contaminants than with total dust. A markers for bacterial peptidoglycan showed better correlation with some changes than endotoxin suggesting that several bacterial constituents may play a role in ODTS. The results in vitro test suggest that swine dust activated a cytokine response in EP and AM. The EP had more limited cytokine response profile than AM. The swine dust is a more potent stimulus for cytokine release than LPS in EP. Both cells can contribute to inflammatory reaction after inhalation swine dust, and several agents including LPS may play important role in those cytokine release.
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| 24. |
- Wang, Zhiping, et al.
(författare)
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An extended production-inventory system and its modelling
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- With today's global competitive environment and changing customer requirements, companies are nowadays shifting from product-oriented to customer-oriented production. In this paper, we introduce the concept of an "extended production-inventory system". The concept means that customers are included as a part of production-inventory systems; this could be regarded as an extreme case of customer-oriented manufacturing. Based on that concept, a simple extended productioninventory system is presented. In the system, the objectives of both manufacturer and customer are considered simultaneously, and it is shown how the system can be mathematically modelled applyingmultiple-objective decision-making techniques. Moreover, a numerical example is provided to illustrate how the weights of different objectives influence the optimal solutions. The strategy of customisation, facilitated by e-business, is incorporated in the model as well.
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| 25. |
- Wang, Zhiping, 1969-
(författare)
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Capacity-constrained production-inventory systems : using Laplace transforms and input-output analysis
- 2001
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work is concerned with multi-level, multi-stage capacity-constrained production-inventory problems. The aim is to provide a contribution to a theoretical background for Material Requirements Planning (MRP) using the Laplace Transform approach and Input-Output Analysis.In an extensive literature survey, we summarise the work on the capacitated lot-sizing problem (CLSP) within both the deterministic and the stochastic environments. Certain aspects related to model formulation are highlighted. It was found that methods for solving this class of problems have been concentrating on heuristics and mathematical programming.Unlike classic methods, this thesis formulates models for capacityconstrained production-inventory systems using the Laplace transform and input-output analysis. As a first step to incorporate capacity limitations into previous theory, we introduce alternative formulations of extensions to MRP theory in order to incorporate capacity constraints. We focus our attention on the way in which the fundamental balance equations for inventory and backlogs need to be modified.Then we develop a stochastic model, in which external demand for end items is assumed to be unknown. Unlike the classic total cost objective function, the Net Present Value is used as the objective function. As an intermediate result, the backlog function for a discrete time demand process is derived. Besides, an extension of the model is presented in which both capacity and demand are considered along a continuous time scale, without time buckets.Numerical examples are provided to explain the theory both in the deterministic and in the stochastic situations.
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| 26. |
- Wang, Zhiping, 1969-
(författare)
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Capacity-constrained production-inventory systems : modelling and analysis in both a traditional and an e-business context
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses issues in production-inventory systems in both a traditional and an e-business context, with an emphasis on capacity considerations. The general aim of the thesis is to model capacity-constrained production-inventory systems and thereby provide theoretical frameworks for control as well as design of these systems.The research has been conducted in two different contexts. In the traditional context, an extensive survey of the literature on capacity-constrained production-inventory systems is first presented. Production-inventory systems with capacity limitations are then modelled using the Laplace transform and input-output analysis for deterministic and stochastic demand situations, respectively. In the formulation of the model for the deterministic demand situations, the focus is on the way in which the fundamental balance equations for inventory and backlogs need to be modified. In the formulation for stochastic demand situations, the model extends previous theory in the direction of capacity considerations combined with uncertainty in external demand. The results of the modelling and analysis in the traditional context contribute to the development of a theoretical background for production-inventory system control applying the Laplace transform approach and input-output analysis.In the e-business context, those aspects which are affected by e-business based customer ordering systems, and hence influence production-inventory systems, are studied. A mathematical model based on the assumption of a simple e-business model of direct sales channels is presented. Since e-business significantly facilitates customisation, models of two different production systems which consider customisation are provided. The production-inventory systems are then developed into an extended system where customers are included. For this system, a multiple objective formulation is obtained, in view of the importance of customers. The results of the modelling and analysis in the ebusiness context contribute insights and perspectives on ways to design and control ebusiness influenced production - inventory systems.
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| 27. |
- Wang, Zhiping, 1969-, et al.
(författare)
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Modelling customisation in production-inventory systems
- 2004
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Ingår i: Proceedings of the 2nd World POM Conference.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With the implementation of e-business, customisation is increasingly becoming a competitive strategy for manufacturing companies. From both theoretical and practical perspectives, however, there is limited knowledge about the influence of customisation on the operational level. In this paper, we model two different production systems: the single machine production system with a cyclical production policy and the serial production system with a decoupling point, where customisation is considered. These models provide a theoretical framework for designing a production-inventory system in practice. As for the solutions yielded by the models, the most interesting finding is that capacity requirement increases with customer order lead-time in the serial production system in one of the cases’ solutions, which is counterintuitive. This result is due to the complexity of the relationship between the variables of decoupling point position and capacity requirements and the parameter of customer order leadtime in the mathematical formulation.
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| 28. |
- Wang, Zhiping, et al.
(författare)
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The impact of e-business based customer ordering systems on traditional production-inventory systems
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- E-business is developing very rapidly as a new way of working. It brings some advantages for production-inventory management. Despite its great impact, research on the influence of e-business on production-inventory systems is very rare. In this paper, we first study those aspects which are affected by e-business-based customer ordering systems and then influence production-inventory systems. A mathematic model is then presented based on an assumption of simple e-business model of direct sales channel. Discussions are given on issues related to the system.
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