| 1. |
- Alieva, Jamila, 1987-
(författare)
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Digital Waste – misjudged element of value stream in lean manufacturing
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing prevalence of digital technologies in manufacturing is aimed at enhancing and streamlining traditional lean processes. However, the rapid automation of manufacturing brings about challenges due to a limited understanding of production waste mechanisms by practitioners. There is growing concern about the potential emergence of digital waste as a result of the influence of digital technologies on lean manufacturing. This thesis aims to examine the role of digital waste within the overall waste in digitalized lean manufacturing, as well as the impact of technologies on lean waste and practices.The thesis is driven by three research questions and comprises five papers that stem from five individual studies. The initial study explores the potential classification of uncollected and unprocessed data as a novel manifestation of Muda, or digital waste. The subsequent study seeks to assess the capability of implementing ERP at a supply chain level to amplify latent lean efficiencies within entities. Lastly, the third study delves into the perceived impacts of soft management practices, employee behaviors, the integration of digital technologies in manufacturing facilities, and their connection to the emergence of digital waste. The fourth study delves into the digital waste generated by companies with automated lean practices, while the fifth study explores the factors contributing to digital waste within the European manufacturing sector.The findings uncover the existence of a novel type of waste, known as digital waste, which may originate from either the product itself or the production process. The findings reveal that the use of ERP technology has a significant impact on identifying hidden lean potential across three categories: unlocked hidden lean potential in an unconnected ERP system, unlocked hidden lean potential in a connected ERP system, and hidden lean potential in a shared ERP system. Furthermore, the study indicates that various aspects such as top management leadership, middle management involvement, employee education, corporate social responsibility focus, innovation, knowledge sharing, work-family balance, psychological capital, job satisfaction, and career commitment, which fall under soft lean management practices, are positively influenced by the digital transformation process. Conversely, soft lean management practices, such as employee training, creativity, discretionary effort, turnover intention, and proactivity, appear to be negatively impacted by digital transformation. Additionally, the final results suggest the existence of digital waste in supplier-related lean practices (specifically, automated JIT delivery) within product-oriented and service-oriented technologies, as well as in internally related lean practices (specifically, automated set-up) within process-oriented technologies. Furthermore, evidence of digital waste is observed in customer-related lean practices, particularly those involving digitally engaged customers, across product-, service-, and process-oriented technologies. Finally, the study reveals that a majority of European manufacturers collect and process data for multiple purposes.The research presented in this thesis adds significant value to the ongoing discourse surrounding lean waste by engaging in a theoretical discussion of both physical and digital waste in the context of technological advancements. This thesis contributes to the discourse surrounding the automation of lean methodologies across product, process, and system domains, while also examining the influence of digital transformation on lean management practices. Furthermore, it investigates the role and consequences of Enterprise Resource Planning (ERP) systems in lean production. In practical terms, the thesis validates the presence of a novel type of waste that can impact the cost management of manufactured products, fosters transparency for digital collaboration, and advocates for increased investment in technologies and specialized personnel to offer analytical services in conjunction with manufacturing products.
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| 2. |
- Arena, Maurizio, et al.
(författare)
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Novel Aluminum Alloy Tailored for Additive Manufacturing : Structural Characterization and Qualification Perspectives
- 2024
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- Featured Application The paper demonstrates key structural characteristics of a novel aluminum alloy conceived for AM-based components in the aviation frame.Abstract The recent advances achieved in additive manufacturing (AM) technology demonstrate the potential to realize customized metal components, ensuring weight reduction opportunities. These benefits make AM attractive for high-cost aerospace applications, especially where high geometric complexity is required. In the context of an EU research scenario, the H2020 MANUELA (Additive Manufacturing Using Metal Pilot Line) project promotes the development of new technologies for design optimization by enabling the application of novel materials in AM. This paper illustrates recent advances in a new aluminum alloy (Al-HS1) with high strength emphasizing all of the characterization steps at the coupon level. This material has been employed in the re-engineering of a conventional hydraulic manifold using a powder bed fusion-laser beam (PBF-LB) process. Both the simulations and structural tests allowed for proving its compliance and technological maturity with industrial standards and applicable airworthiness requirements.
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| 3. |
- Bengtsson, S., et al.
(författare)
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New Aluminium Alloy Tailored For Powder Bed Fusion - Laser Beam Process
- 2022
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Ingår i: World PM 2022 Congress Proceedings.
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Konferensbidrag (refereegranskat)abstract
- The powder bed fusion - laser beam (PBF-LB) process can produce parts with complex geometry. Light weight designs can be created and by using light alloys further weight savings can be achieved. However, minimizing printing defects using standard aluminium alloys, such as 2000, 6000 and 7000 series alloys, have proved to be difficult since they are all prone to solidification cracking. In the present study, two aluminium alloys are addressed: The first alloy is the AlSi10Mg alloy known for easy printing and consistent quality in PBF-LB printing process. The second material is a novel alloy from self-developed Al-Mn-Cr-Zr family of alloys designed to inherently resist solidification cracking, while also providing strong ageing response. The quality of printing and the resulting mechanical properties are compared. The results show that the new material prints in a robust way and that the mechanical properties are superior to those of AlSi10Mg.
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| 4. |
- Jazairy, Amer, 1989-
(författare)
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Engaging in green logistics: An eye on shippers, logistics service providers, and their interactions
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The logistics and transport industry places a heavy load on the environment, causing various harms such as air pollution, global warming and resource depletion. The logistics and supply chain management literature assigns the largest share of responsibility for alleviating such harms to two supply chain actors: shippers (i.e., logistics buyers) and logistics service providers (LSPs), which motivated focusing on them in this thesis. Specifically, the purpose of this thesis is to investigate the engagements of shippers and LSPs in different green logistics practices (GLPs) throughout the logistics purchasing process, and to propose improvements for such engagements by their interactions.Three research questions drive this investigation. The first question handles comparing the drivers (i.e., institutional pressures) for shippers to purchase GLPs and for LSPs to provide them—to reveal how this ‘one-tier network’ is driven as a whole. The second question aims to describe how shippers and LSPs engage in the different GLPs throughout the logistics purchasing process (across its four phases: request for proposal, negotiations, contracting and execution) and why such engagement takes place as it does. The third question aims to propose improvements for shippers’ and LSPs’ engagements in the different GLPs throughout the process—by enacting different degrees of interactions (cooperation vs. collaboration). A methodological triangulation approach is used to answer these questions, based on five papers that are extracted from three studies: a single case (shipper-LSP dyad), a multiple case (3 shippers, 5 LSPs) and a survey (169 shippers, 162 LSPs).The findings reveal a lack of direct regulatory, market and competitive pressures on shippers to purchase GLPs. These are compared to existing (yet insufficient) regulatory pressure, effective market pressure and emergent competitive pressure on LSPs to provide GLPs. The findings also reveal gaps between the actors’ purchasing-providing engagements in GLPs across the purchasing process, which followed three patterns: steady & wide, steady & narrow and emergent. Distinct GLPs are associated with each pattern, and detailed explanations are presented for these associations based on the characteristics of each GLP . Further, the findings propose paths to improve the actors’ engagements in GLPs across the process, based on the gap pattern for each GLP and the degrees of shipper-LSP interactions required for it (cooperation vs. collaboration).This thesis contributes to the body of knowledge through systematically incorporating a trilateral actor-, phase- and GLP-specific distinction into the green logistics purchasing discussion. Also, it transcends the descriptive (and general) level of analysis of shippers’ and LSPs’ green engagements during the logistics purchasing process, by: (i) explaining why such engagements occur as they do and (ii) providing recommendations that could actually improve these engagements. Insights are offered to managers at shipper/LSP firms to assist them in modifying their purchasing/marketing strategies throughout the purchasing process with respect to specifically targeted GLPs. Insights are also offered to policymakers to set suitable regulations on both actors to support ‘greening’ logistics networks.
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| 5. |
- Kaltenbrunner, Monica, 1975-, et al.
(författare)
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Associations between lean maturity in primary care and musculoskeletal complaints among staff : a longitudinal study
- 2023
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThis study had two aims: (1) to determine the prevalence of musculoskeletal complaints among staff in primary care and (2) to determine to what extent lean maturity of the primary care unit can predict musculoskeletal complaints 1 year later.DesignDescriptive, correlational and longitudinal design.SettingPrimary care units in mid-Sweden.ParticipantsIn 2015, staff members responded to a web survey addressing lean maturity and musculoskeletal complaints. The survey was completed by 481 staff members (response rate 46%) at 48 units; 260 staff members at 46 units also completed the survey in 2016.Outcome measuresAssociations with musculoskeletal complaints were determined both for lean maturity in total and for four Lean domains entered separately in a multivariate model, that is, philosophy, processes, people and partners, and problem solving.ResultsThe shoulders (12-month prevalence: 58%), neck (54%) and low back (50%) were the most common sites of 12-month retrospective musculoskeletal complaints at baseline. Shoulders, neck and low back also showed the most complaints for the preceding 7 days (37%, 33% and 25%, respectively). The prevalence of complaints was similar at the 1-year follow-up. Total lean maturity in 2015 was not associated with musculoskeletal complaints, neither cross-sectionally nor 1 year later, for shoulders (1 year beta: -0.002, 95% CI -0.03 to 0.02), neck (beta: 0.006, 95% CI -0.01 to 0.03), low back (beta: 0.004, 95% CI -0.02 to 0.03) and upper back (beta: 0.002, 95% CI -0.02 to 0.02).ConclusionThe prevalence of musculoskeletal complaints among primary care staff was high and did not change within a year. The extent of lean maturity at the care unit was not associated with complaints among staff, neither in cross-sectional analyses nor in a 1-year predictive analysis.
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| 6. |
- Mehta, Bharat, et al.
(författare)
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Mechanical properties and microstructural characterisation including high-temperature performance of Al-Mn-Cr-Zr-based alloys tailored for additive manufacturing
- 2024
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Ingår i: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 244
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Tidskriftsartikel (refereegranskat)abstract
- Powder bed fusion-laser beam (PBF-LB), an additive manufacturing process, takes advantage of rapid cooling rates (103-106 K/s) to enable novel aluminium alloys. This study reports the mechanical properties of one such alloy system (Al-Mn-Cr-Zr based). The alloys based on this system are designed to be precipitation hardenable with high service temperatures. To elucidate the precipitation hardening, three alloy variants were studied involving different heat-treated conditions. Uniaxial tensile testing at room temperature revealed yield strengths between 250–500 MPa with elongation to fracture of 5–25 % with high repeatability. To demonstrate high-temperature resistance, two alloy variants in peak hardened condition were tested at temperatures of up to 573 K. Yield strength up to 170 MPa at 573 K was observed. These properties in combination demonstrate highly competitive Al-alloys for high-temperature applications.
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| 7. |
- Mehta, Bharat, 1993, et al.
(författare)
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Thermal Stability In Al-Mn-Cr-Zr Based Aluminium Alloys Tailored For Powder Bed Fusion - Laser Beam
- 2022
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Ingår i: World PM 2022 Congress Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Al-Mn-Cr-Zr family of alloys tailored for powder bed fusion - laser beam process have been developed by the authors. The alloys were designed by leveraging negligible solidification range close to solidification, leading to an "inherently crack free" alloy system. These alloys have been designed to benefit from higher amount of solutes in solid solution, which leads to stronger precipitation hardening via direct ageing to achieve high strengths. Since the alloying elements were selected having low bulk diffusivities, slower precipitation kinetics is expected which suggests retention of high strength even after secondary ageing post peak hardening. Upon secondary ageing the alloys at 523K for 2544 hours and 623K 1054 hours negligible hardness loss at 523K and 17 HV loss at 623K was observed. This was benchmarked against Scalmalloy® which was seen to have negligible hardness loss at 523K and 28 HV loss at 623 K respectively.
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| 8. |
- Riabov, Dmitri, 1990, et al.
(författare)
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Effect of atomization on surface oxide composition in 316L stainless steel powders for additive manufacturing
- 2020
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Ingår i: Surface and Interface Analysis. - : Wiley. - 1096-9918 .- 0142-2421. ; 52:11, s. 694-706
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Tidskriftsartikel (refereegranskat)abstract
- The initial oxide state of powder is essential to the robust additive manufacturing of metal components using powder bed fusion processes. However, the variation of the powder surface oxide composition as a function of the atomizing medium is not clear. This work summarizes a detailed surface characterization of three 316L powders, produced using water atomization (WA), vacuum melting inert gas atomization (VIGA), and nitrogen atomization (GA). X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy analyses were combined to characterize the surface state of the powders. The results showed that the surface oxides consisted of a thin (~4 nm) iron oxide (Fe2O3) layer with particulate oxide phases rich in Cr, Mn, and Si, with a varying composition. XPS analysis combined with depth‐profiling showed that the VIGA powder had the lowest surface coverage of particulate compounds, followed by the GA powder, whereas the WA powder had the largest fraction of particulate surface oxides. The composition of the oxides was evaluated based on the XPS analysis of the oxide standards. Effects of Ar sputtering on the peak positions of the oxide standards were evaluated with the aim of providing an accurate analysis of the oxide characteristics at different etch depths.
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| 9. |
- Torell, Agnes, 1993, et al.
(författare)
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Low CD4+T cell count is related to specific anti-nuclear antibodies, IFNα protein positivity and disease activity in systemic lupus erythematosus pregnancy.
- 2024
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Ingår i: Arthritis research & therapy. - : BioMed Central (BMC). - 1478-6362 .- 1478-6354. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Lymphopenia, autoantibodies and activation of the type I interferon (IFN) system are common features in systemic lupus erythematosus (SLE). We speculate whether lymphocyte subset counts are affected by pregnancy and if they relate to autoantibody profiles and/or IFNα protein in SLE pregnancy.Repeated blood samples were collected during pregnancy from 80 women with SLE and 51 healthy controls (HC). Late postpartum samples were obtained from 19 of the women with SLE. Counts of CD4+and CD8+T cells, B cells and NK cells were measured by flow cytometry. Positivity for anti-nuclear antibodies (ANA) fine specificities (double-stranded DNA [dsDNA], Smith [Sm], ribonucleoprotein [RNP], chromatin, Sjögren's syndrome antigen A [SSA] and B [SSB]) and anti-phospholipid antibodies (cardiolipin [CL] and β2 glycoprotein I [β2GPI]) was assessed with multiplexed bead assay. IFNα protein concentration was quantified with Single molecule array (Simoa) immune assay. Clinical data were retrieved from medical records.Women with SLE had lower counts of all lymphocyte subsets compared to HC throughout pregnancy, but counts did not differ during pregnancy compared to postpartum. Principal component analysis revealed that low lymphocyte subset counts differentially related to autoantibody profiles, cluster one (anti-dsDNA/anti-Sm/anti-RNP/anti-Sm/RNP/anti-chromatin), cluster two (anti-SSA/anti-SSB) and cluster three (anti-CL/anti-β2GPI), IFNα protein levels and disease activity. CD4+T cell counts were lower in women positive to all ANA fine specificities in cluster one compared to those who were negative, and B cell numbers were lower in women positive for anti-dsDNA and anti-Sm compared to negative women. Moreover, CD4+T cell and B cell counts were lower in women with moderate/high compared to no/low disease activity, and CD4+T cell count was lower in IFNα protein positive relative to negative women. Finally, CD4+T cell count was unrelated to treatment.Lymphocyte subset counts are lower in SLE compared to healthy pregnancies, which seems to be a feature of the disease per se and not affected by pregnancy. Our results also indicate that low lymphocyte subset counts relate differentially to autoantibody profiles, IFNα protein levels and disease activity, which could be due to divergent disease pathways.
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| 10. |
- Torell, Agnes, 1993, et al.
(författare)
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Low-density granulocytes are related to shorter pregnancy duration but not to interferon alpha protein blood levels in systemic lupus erythematosus.
- 2023
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Ingår i: Arthritis research & therapy. - : BMC. - 1478-6362. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- An increased risk of pregnancy complications is seen in women with systemic lupus erythematosus (SLE), but the specific immunopathological drivers are still unclear. Hallmarks of SLE are granulocyte activation, type I interferon (IFN) overproduction, and autoantibodies. Here we examined whether low-density granulocytes (LDG) and granulocyte activation increase during pregnancy, and related the results to IFNα protein levels, autoantibody profile, and gestational age at birth.Repeated blood samples were collected during pregnancy in trimesters one, two, and three from 69 women with SLE and 27 healthy pregnant women (HC). Nineteen of the SLE women were also sampled late postpartum. LDG proportions and granulocyte activation (CD62L shedding) were measured by flow cytometry. Plasma IFNα protein concentrations were quantified by single molecule array (Simoa) immune assay. Clinical data were obtained from medical records.Women with SLE had higher LDG proportions and increased IFNα protein levels compared to HC throughout pregnancy, but neither LDG fractions nor IFNα levels differed during pregnancy compared to postpartum in SLE. Granulocyte activation status was higher in SLE relative to HC pregnancies, and it was increased during pregnancy compared to after pregnancy in SLE. Higher LDG proportions in SLE were associated with antiphospholipid positivity but not to IFNα protein levels. Finally, higher LDG proportions in trimester three correlated independently with lower gestational age at birth in SLE.Our results suggest that SLE pregnancy results in increased peripheral granulocyte priming, and that higher LDG proportions late in pregnancy are related to shorter pregnancy duration but not to IFNα blood levels in SLE.
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