| 1. |
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| 2. |
- Hao, Shuang, et al.
(författare)
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A Model for Assessing the Importance of Runoff Forecasts in Periodic Climate on Hydropower Production
- 2023
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 15:8
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Tidskriftsartikel (refereegranskat)abstract
- Hydropower is the largest source of renewable energy in the world and currently dominates flexible electricity production capacity. However, climate variations remain major challenges for efficient production planning, especially the annual forecasting of periodically variable inflows and their effects on electricity generation. This study presents a model that assesses the impact of forecast quality on the efficiency of hydropower operations. The model uses ensemble forecasting and stepwise linear optimisation combined with receding horizon control to simulate runoff and the operation of a cascading hydropower system. In the first application, the model framework is applied to the Dalalven River basin in Sweden. The efficiency of hydropower operations is found to depend significantly on the linkage between the representative biannual hydrologic regime and the regime actually realised in a future scenario. The forecasting error decreases when considering periodic hydroclimate fluctuations, such as the dry-wet year variability evident in the runoff in the Dalalven River, which ultimately increases production efficiency by approximately 2% (at its largest), as is shown in scenarios 1 and 2. The corresponding potential hydropower production is found to vary by 80 GWh/year. The reduction in forecasting error when considering biennial periodicity corresponds to a production efficiency improvement of about 0.33% (or 13.2 GWh/year).
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| 3. |
- Hao, Shuang, et al.
(författare)
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Influence of elicitation procedure and phrasing on health state valuations in experience-based time trade-off tasks among diabetes patients in China
- 2020
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Ingår i: Quality of Life Research. - : SPRINGER. - 0962-9343 .- 1573-2649. ; 29:1, s. 289-301
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Open-ended and iteration-based time trade-off (TTO) tasks can both be used for valuation of health states. It has so far not been examined how the elicitation procedure affects the valuation of experience-based health states. The purpose of this study is to investigate the influence of elicitation procedure on experience-based health state values elicited by the TTO method. Methods 156 Chinese adults with type 2 diabetes participated in face-to-face interviews with an open-ended or an iteration-based TTO task. The association between the type of TTO task and the valuation of health states was investigated through multiple linear regression analyses. A modified open-ended TTO task was also developed (n = 33) to test whether different phrasings of open-ended TTO tasks influence TTO values. Results Higher TTO values were observed in the original open-ended TTO task compared to the iteration-based task, which indicates that the elicitation procedure influences the valuation of health states. When the modified open-ended task was introduced, the difference between the two elicitation procedures was no longer statistically significant, suggesting that the phrasing and/or visual presentation of the TTO task may influence the valuation of health states. Conclusions The choice of elicitation procedure as well as the description of experience-based TTO tasks may influence the valuation of health states. Further research is warranted, also in other cultural contexts, to further explore these findings.
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| 4. |
- Hao, Shuang
(författare)
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Prostate cancer testing in Sweden : the interplay between cost and effectiveness
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As a major cause of male deaths in Sweden, prostate cancer constitutes an essential public health issue to the society. Early detection through an organised testing program with the prostate-specific antigen (PSA) test and systematic biopsy (SBx) has not been adopted in most countries due to potential harms from over-diagnosis and over-treatment of low risk cancers. The magnetic resonance imaging (MRI) and a novel serum-based reflex test Stockholm3 are possible two approaches to tackle this problem. This doctoral thesis aimed to characterise the societal economic burden due to prostate cancer in Sweden and assess the cost-effectiveness of prostate cancer testing using MRI with or without the reflex Stockholm3 test. Study I characterised and illustrated the resource utilisation in the diagnostic and care pathways of prostate cancer in Sweden during the calendar year 2016. A prevalence-based cost-of-illness approach was applied to quantify the resource utilisation and related costs by care type in Stockholm using register-based data. Direct healthcare resources used in the primary, outpatient, inpatient, palliative care and the pharmaceuticals were valued by their unit costs. Informal care and productivity losses were valued by the human capital method. The societal costs in Stockholm were estimated to be €64 million, of which the direct healthcare, informal care and productivity losses accounted for 62%, 28% and 10%, respectively. The extrapolated costs to Sweden were estimated to be €281 million. An average costs of €1,510, €828 and €271 per prevalent case were calculated for the direct healthcare, informal care and productivity losses, respectively. The results were sensitive to the exclusion of primary care visits for those without a diagnosis of prostate cancer and the proxy good method for valuing informal care. Study II assessed the cost-effectiveness by microsimulation for: (i) no screening and quadrennial PSA screening of prostate cancer for men aged 55-69 years from a lifetime societal perspective using; (ii) SBx alone; (iii) MRI and targeted biopsy (TBx) for men with a positive MRI result; (iv) MRI and the combined targeted and systematic biopsies (TBx/SBx) for those who had a positive MRI result; and (v) SBx for men with a negative MRI result and the combined TBx/SBx for those who are MRI positive. Based on the test performance estimated from the data included in a recent Cochrane review, the screening strategies could reduce prostate cancer related mortality by 8-10% compared with no screening, but resulted in incremental cost-effectiveness ratios (ICERs) that were classified as high costs per quality-adjusted life year (QALY) gained in Sweden. MRI-based screening with either TBx or the combined TBx/SBx had a lifetime reduction in the biopsy episodes by approximately 40%, compared with screening using SBx alone. These two MRI-based strategies were associated with lifetime reductions in detecting International Society of Urological Pathology Grade group 1 (GG=1) cancers by 17% and 11%, respectively, and both strategies yielded strong dominance over alternative screening strategies. MRI-based screening with TBx was found to have the lowest ICER relative to no screening. This ICER would lead to a 25% reduction when substituting the background health state values reported by the World Health Organisation (WHO) with a value set measured from the Swedish general population. Study III evaluated the cost-effectiveness comparing: (i) no screening and three quadrennial MRI-based screenings with the combined TBx/SBx on men with a positive MRI result given (ii) positive PSA test value; (iii) positive Stockholm3 test at a reflex threshold of PSA≥1.5ng/mL; and (iv) positive Stockholm3 test at a reflex threshold of PSA≥2ng/mL. Based on the data from the STHLM3-MRI invitation-to-screening trial, the adjustment for the test performance using data from the Cochrane review, and employing a lifetime societal perspective, all screening strategies were associated with a prostate cancer mortality reduction by 7-9%. The ICERs of MRI-based screening strategies in relation to no screening were classified as a moderate cost per QALY gained in Sweden. In comparison with screening without Stockholm3 test, MRI-based screening with Stockholm3 at a reflex test threshold of PSA≥2ng/mL predicted a lifetime reduction of MRI examinations and biopsy episodes by 60% and 9%, respectively, and was considered as the optimal choice for prostate cancer screening. The results were robust in the one-way and probabilistic sensitivity analyses. Study IV further assessed the cost-effectiveness of prostate cancer screening using a microsimulation approach for: (i) no screening; (ii) traditional screening pathway using PSA and SBx; and (iii) MRI-based screening using the combined TBx/SBx on men with a positive MRI result. Test performance was estimated by the evidence from the STHLM3-MRI trial with model-based imputations. Applying a lifetime healthcare perspective, the quadrennial screening strategies reduced prostate cancer related deaths by 6-9%. Compared with the traditional PSA screening pathway, the MRI-based screening with the combined TBx/SBx halved the MRI examinations and reduced cancer over-diagnosis by approximately 50%. The use of MRI and subsequent combined TBx/SBx for screening resulted in an ICER that was classified as moderate cost per QALY gained in Sweden and has high likelihood to be more cost-effective than the traditional PSA screening pathway. Expanding the screening ages to 50-74 years would increase the ICER by approximately 34%. In conclusion, substantial economic burden was estimated for prostate cancer in Sweden, with the main costs from the direct healthcare and informal care provided to the patients. This doctoral thesis contributes to the characterisation and illustration of the resource utilisation and costs alongside the diagnostic and care pathways and provides point references for future economic evaluations in prostate cancer testing and treatment. In the context of screening for men aged 55-69 years and compared with no screening, the incorporation of MRI in the screening program with or without a reflex Stockholm3 test yielded reductions in prostate cancer mortality and over-diagnosis over a lifetime period. Assessing cost-effectiveness from a healthcare perspective and using the background health state values from the Swedish general population, the MRI-based screening resulted in higher QALYs and ICERs that are classified as a moderate cost per QALY gained in Sweden. This doctoral thesis suggests that MRI is considered to be more effective and cost-effective in the population-based screening leveraging the evidence from the screening-by-invitation trial than using estimates from diagnostic patient cohorts and MRI-based screening demonstrates higher probability to be cost-effective than the traditional PSA screening pathway. Screening with MRI can be considered as a cost-effective choice for early detection of prostate cancer in Sweden.
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| 5. |
- Liu, Chang, et al.
(författare)
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Effect of Porosity on Soil-Water Retention Curves : Theoretical and Experimental Aspects
- 2020
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Ingår i: Geofluids. - : Hindawi Limited. - 1468-8115 .- 1468-8123. ; 2020
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Tidskriftsartikel (refereegranskat)abstract
- Porosity change is a common characteristic of natural soils in fluid-solid interaction problems, which can lead to an obvious change of the soil-water retention curve (SWRC). The influence of porosity on soil water retention phenomena is investigated by a theoretical model and an experimental test in this study. A model expressing the change in suction with porosity and effective saturation is put forward theoretically. The model is based on an idealization of three-phase porous materials, the pore structures of which are homogeneous and isotropic. It accounts for the porosity effect on soil water retention, using four parameters with clear physical meanings. The presented model can obtain the SWRC at any porosity, which will reduce the test number required in characterizing the hydraulic behavior of soil. A laboratory experiment for loamy sand with different porosities is performed. The test results show that suction has a significant variation with changes in porosity and decreases with the increase of porosity. The formulation is verified by both the test data and the literature data for FEBEX bentonite and Boom clay. The very good agreements between measured and predicted results show that the SWRC model is reliable and feasible for various soils.
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| 6. |
- Liu, Yi, et al.
(författare)
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Porous, robust, thermally stable, and flame retardant nanocellulose/polyimide separators for safe lithium-ion batteries
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 11:43, s. 23360-23369
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Tidskriftsartikel (refereegranskat)abstract
- The safety of lithium-ion batteries (LIBs) is paramount for all users. One effective way to improve safety is incorporating heat-resistant polyimide (PI) separators, which can increase the thermal stability of batteries and minimize the risk of thermal runaway. However, preparing PI separators with both an ideal pore structure and adequate mechanical properties remains as a challenge. Here, we introduced decabromodiphenyl ethane (DBDPE) and cellulose nanofibers (CNFs) into PI and produced a hybrid separator with an outstanding pore structure and excellent mechanical properties. Aided with DBDPE, the separators attain a well-defined and uniform pore size (20 nm), while demonstrating high porosities (78%) through phase inversion processes. Owing to the addition of CNFs, the mechanical properties of the separators were significantly improved, with a tensile strength of 25.4 MPa and an elastic modulus of 550.1 MPa. Moreover, the separators demonstrate high ion conductivity (0.45 mS cm-1), excellent thermal-dimensional stability (up to 200 degrees C), remarkable flame retardancy, and outstanding electrolyte wettability. At room temperature, the batteries with the separators demonstrate comparable performance with those of polypropylene (PP) separators. However, when subjected to thermal shock treatments, the batteries with the separators outperform those with PP, showcasing their superior performance. The work introduces a novel strategy for designing high-performance separators, thereby paving the way for advancements in the fabrication of LIBs with enhanced safety features. A porous, robust, and thermally stable hybrid separator was developed to solve the dilemma between desired pore structures and mechanical properties in polyimide separators by introducing decabromodiphenyl ethane and cellulose nanofibers.
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| 7. |
- Luo, Yang, et al.
(författare)
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Three-dimensional and temperature-dependent electronic structure of the heavy-fermion compound CePt2In7 studied by angle-resolved photoemission spectroscopy
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:11
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional and temperature-dependent electronic structures of the heavy-fermion superconductor CePt2In7 are investigated. Angle-resolved photoemission spectroscopy using variable photon energy establishes the existence of quasi-two- and three-dimensional Fermi surface topologies. Temperature-dependent 4d-4f on-resonance photoemission spectroscopies data reveal that heavy quasiparticle bands begin to form at a temperature well above the characteristic (coherence) temperature T+. The emergence of low-lying crystal electric field excitation may be responsible for the "relocalization" or the precursor to the establishment of heavy electrons coherence in heavy-fermion compounds. These findings provide critical insight into understanding the hybridization in heavy-fermion systems.
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| 8. |
- Song, Jiao-Jiao, et al.
(författare)
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The 4f-Hybridization Strength in CemMnIn3m+2n Heavy-Fermion Compounds Studied by Angle-Resolved Photoemission Spectroscopy
- 2021
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Ingår i: Chinese Physics Letters. - : IOP Publishing. - 0256-307X .- 1741-3540. ; 38:10
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Tidskriftsartikel (refereegranskat)abstract
- We systemically investigate the nature of Ce 4f electrons in structurally layered heavy-fermion compounds CemMnIn3m+2n (with M = Co, Rh, Jr, and Pt, m = 1, 2, n = 0-2), at low temperature using on-resonance angle-resolved photoemission spectroscopy. Three heavy quasiparticle bands f(0), f(7/2)(1) and f(5/2)(1), are observed in all compounds, whereas their intensities and energy locations vary greatly with materials. The strong f(0) states imply that the localized electron behavior dominates the Ce 4f states. The Ce 4f electrons are partially hybridized with the conduction electrons, making them have the dual nature of localization and itinerancy. Our quantitative comparison reveals that the f(5/2)(1)-f (0) intensity ratio is more suitable to reflect the 4f-state hybridization strength.
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| 9. |
- Swami, Viren, et al.
(författare)
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The Attractive Female Body Weight and Female Body Dissatisfaction in 26 Countries Across 10 World Regions : Results of the International Body Project I
- 2010
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Ingår i: Personality and Social Psychology Bulletin. - : Sage Publications. - 0146-1672 .- 1552-7433. ; 36:3, s. 309-325
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Tidskriftsartikel (refereegranskat)abstract
- This study reports results from the first International Body Project (IBP-I), which surveyed 7,434 individuals in 10 major world regions about body weight ideals and body dissatisfaction. Participants completed the female Contour Drawing Figure Rating Scale (CDFRS) and self-reported their exposure to Western and local media. Results indicated there were significant cross-regional differences in the ideal female figure and body dissatisfaction, but effect sizes were small across high-socioeconomic-status (SES) sites. Within cultures, heavier bodies were preferred in low-SES sites compared to high-SES sites in Malaysia and South Africa (ds = 1.94-2.49) but not in Austria. Participant age, body mass index (BMI), and Western media exposure predicted body weight ideals. BMI and Western media exposure predicted body dissatisfaction among women. Our results show that body dissatisfaction and desire for thinness is commonplace in high-SES settings across world regions, highlighting the need for international attention to this problem.
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| 10. |
- Weng, Wubin, et al.
(författare)
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Optical investigation of gas-phase KCl/KOH sulfation in post flame conditions
- 2018
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 224, s. 461-468
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Tidskriftsartikel (refereegranskat)abstract
- A counter-flow reactor setup was designed to investigate the gas-phase sulfation and homogeneous nucleation of potassium salts. Gaseous KOH and KCl were introduced into the post-flame zone of a laminar flat flame. The hot flame products mixed in the counter-flow with cold N2, with or without addition of SO2. The aerosols formed in the flow were detected through Mie scattering of a 355 nm laser beam. The temperature distribution of the flow was measured by molecular Rayleigh scattering thermometry. From the temperature where nucleation occurred, it was possible to identify the aerosols formed. Depending on the potassium speciation in the inlet and the presence of SO2, they consisted of K2SO4, KCl, or K2CO3, respectively. The experiments showed that KOH was sulphated more readily than KCl, resulting in larger quantities of aerosols. The sulfation process in the counter-flow setup was simulated using a chemical kinetic model including a detailed subset for the Cl/S/K chemistry. Similar to the experimental results, much more potassium sulfate was predicted when seeding KOH compared to seeding KCl. For both KOH and KCl, sulfation was predicted to occur primarily through the reactions among atomic K, O2 and SO2, forming KHSO4 and K2SO4. The higher propensity for sulfation of KOH compared to KCl was mostly attributed to the lower thermal stability of KOH, facilitating formation of atomic K. According to the model, sulfation also happened through SO3, especially for KCl (KCl → KSO3Cl → K2SO4).
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