bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stabilization of Low-NOx Hydrogen Flames on a Dual-Swirl Coaxial Injector
Authors: Leroy Maxime , Mirat Clément , Renaud Antoine , Vicquelin Ronan 
Published: September 2022

Abstract
Hydrogen-fueled carbon-free energy is a growing prospect for the future of several industries, including the aeronautical and energy generation sectors. However, the transition to hydrogen comes with several challenges: flame stabilization due to the unique combustion properties of hydrogen compared to conventional fuels and control of nitrogen oxides (NOx) production due to the higher combustion temperature. In addition, the high flammability of hydrogen poses an increased risk of flashback in premixed configurations commonly used to generate low-NOx flames. As a consequence, research into strategies for low-NOx hydrogen combustion is developing, and several technologies are being considered for industrial use. Among these technologies, we consider here a dual swirl coaxial injector operated in nonpremixed conditions. This setup enables the stabilization of multiple types of flame structures that are parametrically investigated for their NOx emissions. The flame structure is observed using OH* chemiluminescence images collected using an intensified CCD camera equipped with a bandpass filter. Exhaust gas species mole fractions of NO, NO2, and O2 are measured using NDIR gas detectors and a paramagnetic sensor. This investigation reveals that stabilization of hydrogen-air flames on the double swirl injector is possible and that varying the flow parameters induces changes in structure that affect NOx emissions, independently of swirl level, residence time, and temperature that also play a role. The study is carried out at atmospheric pressure.
Thermodynamic Assessment of the Conversion of a Typical CCGT Power Plant to a Fully E-Fuel Fired Unit
Authors: Rigaud Jérôme , De Paepe Ward , Laget Hannes 
Published: September 2022

Abstract
With the increasing need for flexibility in the electricity grid, combined with longer periods of low electricity prices due to an oversupply of renewable electricity, alternative solutions which include the production of carbon-free fuels in combination with the use of combined cycle power plants, are identified as a possible solution. These so-called power-to-gas-to-power solutions (P2G2P), with hydrogen and ammonia as fuel, require further research to determine their feasibility. Within this scope, the European collaborative project FLEXnCONFU aims at providing an answer toward this feasibility. The specific project idea is to recover excess grid power to produce hydrogen through proton exchange membrane (PEM) water electrolysis. Then, this hydrogen could be stored directly, or it could be fed in an ammonia synthesis process. Finally, the decarbonized fuels (ammonia and/or hydrogen) are burned in the gas turbine to produce electricity with no greenhouse gases (GHG) emission. The aim of this paper is to evaluate the impact of P2G2P system integration in a power plant. Different concepts have been applied to an existing ENGIE plant, based in Belgium, with the idea of installing all the technologies (electrolyzers, compressors, and storage, as well as ammonia fabrication units) on the power plant site. Simulations show that a considerable production time is needed to operate the plant for several hours using these e-fuels. Moreover, hydrogen storage requires an extremely huge footprint, hence it looks more reasonable to operate ammonia synthesis to store large quantities of decarbonized fuel, given the site space constraints. Additionally, Aspen plus models have been realized to evaluate the global efficiency of the P2G2P systems as well as the specific cooling requirements of the added technologies. The global efficiency for the P2H2P (with hydrogen) system is 32%. For the P2A2P (with pure ammonia) and power-to-amonia-to-hydrogen-to power (part of the produced ammonia is cracked to recover hydrogen, feeding the combustion chamber of the combined cycle gas turbine (CCGT) with a blend of 70% NH3 and 30% H2) systems, this global efficiency is reduced, respectively, to 24% and 19%. From these results, it is thus apparent that there remain still several challenges that need to be overcome to make P2G2P an efficient way to decarbonize electricity production. These main challenges are: Increase the efficiency of the transformation processes to limit the energy losses; Enhance hydrogen storage technologies to limit the footprint or develop an efficient hydrogen distribution; Reduce the cost of P2G technologies and especially of PEM electrolyzers; Progress on decarbonized fuels combustion and specifically limit NOx emission for the NH3 firing configuration.
A Reduction Technique for the Calculation of the Forced Response of Bladed Disks in the Presence of Contact Mistuning at Blade Root Joints
Authors: Pinto Valeria , Battiato Giuseppe , Firrone Christian Maria 
Published: September 2022

Abstract
The effect of differences in nominally equal sectors of a bladed disk (mistuning) is a well-known problem for designers since the forced response may show localized amplification of the blade response with respect to a cyclically symmetric (tuned) configuration. In order to perform a large number of simulations in a reasonable amount of time to characterize the highest blade response, corresponding to the worst mistuning pattern, reduction techniques have been developed, where the mistuning is introduced directly in a compact, reduced order model (ROM) obtained from very large finite element (FE) models. Typically, mistuning is introduced in the ROM in terms of natural frequency perturbations of the blade; nevertheless, a better insight is specifically required in order to correlate mistuning to a specific source (geometrical, material, contact mistuning). In this paper, a reduction technique is presented to take into account mistuning due to the contact uncertainties at the blade root joint, which can be caused by design tolerances, manufacturing process, assembly procedures, wear, etc. The technique takes its basis from the Craig–Bampton component mode synthesis (CB-CMS) applied to the uncoupled blade and disk sector, which is typically included in most of the FE software for easy implementation in standard industrial practice. The full set of master degrees-of-freedom (DOFs) at the random contacts are purposely reduced using an optimal local modal basis based on the Gram–Schmidt interface (GSI) technique developed by the authors. Experimental evidence of actual uncertain contact obtained during joint preloading is used to find an appropriate base to represent typical contact patterns.
Sintering Behavior of Lunar Soil Heated by Indirect and Direct Concentrated Sunlight
Authors: Biswas Diprajit , Cox Thomas , Lapp Justin L. 
Published: September 2022

Abstract
Construction material is one important need for long-term habitation on the moon. Solar radiation, when concentrated for high heat flux, can heat lunar soil, or regolith, until it sinters at temperatures above 900°C. The solid, sintered regolith can be used for construction material. This work explores the conditions which lead to effective sintering of lunar soil for both directly irradiated sintering and indirect sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. The resulting depth of sintering, amount of material sintered, and the compressive strength of the sintered material were recorded. A sintering range of 860°C–1140°C was identified. Limited compressive strength data showed higher strength for indirect sintering.
Preliminary Thermal and Structural Analysis of High Temperature Multilayered Thermal Energy Storage Bin in a Particle Heating Receiver Based Thermal Power Plants
Authors: Sarfraz Muhammad , Alaqel Shaker , Saleh Nader S. , Saeed Rageh , Djajadiwinata Eldwin , Alswaiyd Abdulelah , Repole Kenzo , Yeung Ryan , Danish Syed , El-Leathy Abdelrahman , Al-Suhaibani Zeyad , Almuthairi Zeyad , Jeter Sheldon , Al-Ansary Hany 
Published: September 2022

Abstract
Thermal Energy Storage (TES) bins are considered critical components in particle heating receiver-based concentrated solar thermal power (PHR-CSP) plants. Their reliability and efficiency play an integral part in ensuring the commercialization of particle-based CSP technology. Heat loss/leakage from TES walls, particle erosion, thermal and structural stresses during charging/discharging, and hot/cold startup are some of the roadblocks that need to be addressed adequately before commercializing the PHR-CSP technology. To achieve this target, our teams at King Saud University (KSU) and Georgia Institute of Technology (GIT) have successfully demonstrated the multilayered TES bin in the past to store solid particles at a temperature of 700°C. To achieve a higher thermal efficiency of the plant, the particles are required to be heated at temperatures above 1000°C. This causes high thermal and structural stresses to the TES bin walls or layers. At such high particle temperatures, it is important to understand the material properties and interactions between different layers of the TES bin because each layer has different thermal conductivity and coefficient of linear thermal expansion. In this paper, the results of thermal and structural analysis on the TES bin design will be presented and interpreted as how the TES wall layers (insulating firebrick, insulating perlite concrete, expansion layer, and reinforced concrete) will interact with each other. This analysis is important to understand that how thermal and mechanical stresses affect, not only the materials but their interfaces as well. Moreover, it will provide an initial assessment of the TES bin’s thermal and structural integrity at high temperatures.
The End of the War in Afghanistan: The Defeat of the United States and the Consequences for Regional Security
Authors: Bobkin N. N. 
Published: September 2022

Abstract
The studies that have generated the present article have been sparked by a timely question: how does the waning of Western military presence in Afghanistan impact the wider region around this country? The implications of this process go far beyond the immediate effects of the reduction of forces by the U.S. and its allies in the coalition led by NATO. The states in close geographic proximity to Afghanistan, as well as other external powers, notably Russia, have interests in how the transformation of the regional security environment occurs. This article provides background information for understanding the Biden administration’s decision to complete the withdrawal of troops from Afghanistan, assesses the reaction of neighboring countries to the rise of the Taliban, and examines the political and military consequences of regime change in Afghanistan and their impact on regional security. Some additional lines of research are considered as needed. The article ends with considerations and conclusions regarding the possible impact of the current situation in Afghanistan on the subsequent US policy in the region.
Modifiable risk factors and long term risk of type 2 diabetes among individuals with a history of gestational diabetes mellitus: prospective cohort study
Authors: Yang Jiaxi , Qian Frank , Chavarro Jorge E , Ley Sylvia H , Tobias Deirdre K , Yeung Edwina , Hinkle Stefanie N , Bao Wei , Li Mengying , Liu Aiyi , Mills James L , Sun Qi , Willett Walter C , Hu Frank B , Zhang Cuilin 
Published: September 2022

AbstractObjectivesTo evaluate the individual and combined associations of five modifiable risk factors with risk of type 2 diabetes among women with a history of gestational diabetes mellitus and examine whether these associations differ by obesity and genetic predisposition to type 2 diabetes.DesignProspective cohort study.SettingNurses’ Health Study II, US.Participants4275 women with a history of gestational diabetes mellitus, with repeated measurements of weight and lifestyle factors and followed up between 1991 and 2009.Main outcome measureSelf-reported, clinically diagnosed type 2 diabetes. Five modifiable risk factors were assessed, including not being overweight or obese (body mass index <25.0), high quality diet (top two fifthsof the modified Alternate Healthy Eating Index), regular exercise (≥150 min/week of moderate intensity or ≥75 min/week of vigorous intensity), moderate alcohol consumption (5.0-14.9 g/day), and no current smoking. Genetic susceptibility for type 2 diabetes was characterised by a genetic risk score based on 59 single nucleotide polymorphisms associated with type 2 diabetes in a subset of participants (n=1372).ResultsOver a median 27.9 years of follow-up, 924 women developed type 2 diabetes. Compared with participants who did not have optimal levels of any of the risk factors for the development of type 2 diabetes, those who had optimal levels of all five factors had >90% lower risk of the disorder. Hazard ratios of type 2 diabetes for those with one, two, three, four, and five optimal levels of modifiable factors compared with none was 0.94 (95% confidence interval 0.59 to 1.49), 0.61 (0.38 to 0.96), 0.32 (0.20 to 0.51), 0.15 (0.09 to 0.26), and 0.08 (0.03 to 0.23), respectively (Ptrend<0.001). The inverse association of the number of optimal modifiable factors with risk of type 2 diabetes was seen even in participants who were overweight/obese or with higher genetic susceptibility (Ptrend<0.001). Among women with body mass index ≥25 (n=2227), the hazard ratio for achieving optimal levels of all the other four risk factors was 0.40 (95% confidence interval 0.18 to 0.91). Among women with higher genetic susceptibility, the hazard ratio of developing type 2 diabetes for having four optimal factors was 0.11 (0.04 to 0.29); in the group with optimal levels of all five factors, no type 2 diabetes events were observed.ConclusionsAmong women with a history of gestational diabetes mellitus, each additional optimal modifiable factor was associated with an incrementally lower risk of type 2 diabetes. These associations were seen even among individuals who were overweight/obese or were at greater genetic susceptibility.
Margin status and survival outcomes after breast cancer conservation surgery: prospectively registered systematic review and meta-analysis
Authors: Bundred James R , Michael Sarah , Stuart Beth , Cutress Ramsey I , Beckmann Kerri , Holleczek Bernd , Dahlstrom Jane E , Gath Jacqui , Dodwell David , Bundred Nigel J 
Published: September 2022

AbstractObjectiveTo determine if margin involvement is associated with distant recurrence and to determine the required margin to minimise both local recurrence and distant recurrence in early stage invasive breast cancer.DesignProspectively registered systematic review and meta-analysis of literature.Data sourcesMedline (PubMed), Embase, and Proquest online databases. Unpublished data were sought from study authors.Eligibility criteriaEligible studies reported on patients undergoing breast conserving surgery (for stages I-III breast cancer), allowed an estimation of outcomes in relation to margin status, and followed up patients for a minimum of 60 months. Patients with ductal carcinoma in situ only or treated with neoadjuvant chemotherapy or by mastectomy were excluded. Where applicable, margins were categorised as tumour on ink (involved), close margins (no tumour on ink but <2 mm), and negative margins (≥2 mm).Results68 studies from 1 January 1980 to 31 December 2021, comprising 112 140 patients with breast cancer, were included. Across all studies, 9.4% (95% confidence interval 6.8% to 12.8%) of patients had involved (tumour on ink) margins and 17.8% (13.0% to 23.9%) had tumour on ink or a close margin. The rate of distant recurrence was 25.4% (14.5% to 40.6%) in patients with tumour on ink, 8.4% (4.4% to 15.5%) in patients with tumour on ink or close, and 7.4% (3.9% to 13.6%) in patients with negative margins. Compared with negative margins, tumour on ink margins were associated with increased distant recurrence (hazard ratio 2.10, 95% confidence interval 1.65 to 2.69, P<0.001) and local recurrence (1.98, 1.66 to 2.36, P<0.001). Close margins were associated with increased distant recurrence (1.38, 1.13 to 1.69, P<0.001) and local recurrence (2.09, 1.39 to 3.13, P<0.001) compared with negative margins, after adjusting for receipt of adjuvant chemotherapy and radiotherapy. In five studies published since 2010, tumour on ink margins were associated with increased distant recurrence (2.41, 1.81 to 3.21, P<0.001) as were tumour on ink and close margins (1.44, 1.22 to 1.71, P<0.001) compared with negative margins.ConclusionsInvolved or close pathological margins after breast conserving surgery for early stage, invasive breast cancer are associated with increased distant recurrence and local recurrence. Surgeons should aim to achieve a minimum clear margin of at least 1 mm. On the basis of current evidence, international guidelines should be revised.Systematic review registrationCRD42021232115.
Effects of zinc and vitamin A supplementation on prognostic markers and treatment outcomes of adults with pulmonary tuberculosis: a systematic review and meta-analysis
Authors: Wagnew Fasil , Alene Kefyalew Addis , Eshetie Setegn , Wingfield Tom , Kelly Matthew , Gray Darren 
Published: September 2022

IntroductionUndernutrition is a major risk factor for tuberculosis (TB), which is estimated to be responsible for 1.9 million TB cases per year globally. The effectiveness of micronutrient supplementation on TB treatment outcomes and its prognostic markers (sputum conversion, serum zinc, retinol and haemoglobin levels) has been poorly understood. This study aimed to determine the effect of zinc and vitamin A supplementation on prognostic markers and TB treatment outcomes among adults with sputum-positive pulmonary TB.MethodsA systematic literature search for randomised controlled trials (RCTs) was performed in PubMed, Embase and Scopus databases. Meta-analysis with a random effect model was performed to estimate risk ratio (RR) and mean difference (MD), with a 95% CI, for dichotomous and continuous outcomes, respectively.ResultsOur search identified 2195 records. Of these, nine RCTs consisting of 1375 participants were included in the final analyses. Among adults with pulmonary TB, zinc (RR: 0.94, 95% CI: 0.86 to 1.03), vitamin A (RR: 0.90, 95% CI: 0.80 to 1.01) and combined zinc and vitamin A (RR: 0.98, 95% CI: 0.89 to 1.08) supplementation were not significantly associated with TB treatment success. Combined zinc and vitamin A supplementation was significantly associated with increased sputum smear conversion at 2 months (RR: 1.16, 95% CI: 1.03 to 1.32), serum zinc levels at 2 months (MD: 0.86 μmol/L, 95% CI: 0.14 to 1.57), serum retinol levels at 2 months (MD: 0.06 μmol/L, 95% CI: 0.04 to 0.08) and 6 months (MD: 0.12 μmol/L, 95% CI: 0.10 to 0.14) and serum haemoglobin level at 6 months (MD: 0.29 μg/dL, 95% CI: 0.08 to 0.51), among adults with pulmonary TB.ConclusionsProviding zinc and vitamin A supplementation to adults with sputum-positive pulmonary TB during treatment may increase early sputum smear conversion, serum zinc, retinol and haemoglobin levels. However, the use of zinc, vitamin A or both was not associated with TB treatment success.PROSPERO registration numberCRD42021248548.
Institutionalising maternal and newborn quality-of-care standards in Bangladesh, Ghana and Tanzania: a quasi-experimental study
Authors: Manu Alexander , Billah Sk Massum , Williams John , Kilima Stella , Yeji Francis , Matin Ziaul , Hussein Asia , Gohar Fatima , Wobil Priscilla , Baffoe Peter , Karim Farhana , Muganyizi Projestine , Mogela Deus , El Arifeen Shams , Vandenent Maya , Aung Kyaw , Shetye Mrunal , Dickson Kim Eva , Zaka Nabila , Pearson Luwei , Hailegebriel Tedbabe D 
Published: September 2022

IntroductionFacility interventions to improve quality of care around childbirth are known but need to be packaged, tested and institutionalised within health systems to impact on maternal and newborn outcomes.MethodsWe conducted cross-sectional assessments at baseline (2016) and after 18 months of provider-led implementation of UNICEF/WHO’s Every Mother Every Newborn Quality Improvement (EMEN-QI) standards (preceding the WHO Standards for improving quality of maternal and newborn care in health facilities). 19 hospitals and health centres (2.8M catchment population) in Bangladesh, Ghana and Tanzania were involved and 24 from adjoining districts served for ‘comparison’. We interviewed 43 facility managers and 818 providers, observed 1516 client–provider interactions, reviewed 12 020 records and exit-interviewed 1826 newly delivered women. We computed a 39-criteria institutionalisation score combining clinical, patient rights and cross-cutting domains from EMEN-QI and used routine/District Health Information System V.2 data to assess the impact on perinatal and maternal mortality.ResultsEMEN-QI standards institutionalisation score increased from 61% to 80% during EMEN-QI implementation, exceeding 75% target. All mortality indicators showed a downward trajectory though not all reached statistical significance. Newborn case-fatality rate fell significantly by 25% in Bangladesh (RR=0·75 (95% CI=0·59 to 0·96), p=0·017) and 85% in Tanzania (RR=0.15 (95% CI=0.08 to 0.29), p<0.001), but not in Ghana. Similarly, stillbirth (RR=0.64 (95% CI=0.45 to 0.92), p<0.01) and perinatal mortality in Tanzania reduced significantly (RR=0.59 (95% CI=0.40 to 0.87), p=0.007). Institutional maternal mortality ratios generally reduced but were only significant in Ghana: 362/100 000 to 207/100 000 livebirths (RR=0.57 (95% CI=0.33 to 0.99), p=0.046). Routine mortality data from comparison facilities were limited and scarce. Systematic death audits and clinical mentorship drove these achievements but challenges still remain around human resource management and equipment maintenance systems.ConclusionInstitutionalisation of the UNICEF/WHO EMEN-QI standards as a package is feasible within existing health systems and may reduce mortality around childbirth. Critical gaps around sustainability must be fundamental considerations for scale-up.