bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid‐state synthesis and characterization of cobalt blue core‐shell pigment particles
Authors: Yoneda Mika , Gotoh Kuniaki , Nakanishi Makoto , Fujii Tatsuo , Konishi Yasuhiro , Nomura Toshiyuki
Published: November 2018

Cobalt blue is one of the most chemically and thermally stable blue pigments. However, cobalt is scarce and expensive. To minimize the use of cobalt and reduce production costs and toxicity, cobalt blue core‐shell pigments were synthesized by a solid‐state method, which is cheaper than a liquid‐phase reaction. Small cobalt hydroxide particles and large α‐alumina particles, in various ratios, were used as the starting materials. The dry mixed powders were calcined at 1200°C for 2 hours. Elemental mappings of the surfaces and cross sections of the synthesized particles showed that the cobalt blue had a core‐shell structure. X‐ray diffraction patterns showed that the synthesized cobalt blue consisted of an α‐alumina core and a cobalt aluminate shell. The color tone of the synthesized cobalt blue was evaluated from the lightness (L*) and chroma (C*) values. The color tone of the cobalt blue synthesized in this study was almost same as those of commercially available samples although the cobalt molar fraction was lower than the stoichiometric ratio (Co/(Co + Al) = 0.33, Co/Al = 0.5) which was calculated from the chemical reaction formula.
No empirical evidence to support the hypothesis that daily climate variation has an effect on species’ elevational range size: Reply to Chan et al.
Authors: Field Richard , Qian Hong
Published: November 2018

Following our critique, Chan et al. defend the approach used in their original paper. They reveal their “iterative strategy of SEM” (structural equation modelling), which they claim is “standard” (we show otherwise) and “required for the proper and most effective use of SEM” for hypothesis testing. However, publishing their detailed procedure exposes fundamental flaws: capitalizing on chance and violating important assumptions and principles of SEM. They used the same data to first explore numerous correlations, then fit 29 candidate models (all failed) using the best correlates, then fix model parameters to gain degrees of freedom, then evaluate the “best” model. In producing the “best” model, they fixed five parameters using estimates from regression on the same dataset. They further argue that their stationary bootstrap cures the problems of bias and pseudoreplication; we disagree. At best, Chan et al. developed a hypothesis; they did not perform a valid test of one.
Local environment and space drive multiple facets of stream macroinvertebrate beta diversity
Authors: Perez Rocha Mariana , Bini Luis M. , Domisch Sami , Tolonen Kimmo T. , Jyrkänkallio‐Mikkola Jenny , Soininen Janne , Hjort Jan , Heino Jani
Published: November 2018

Aim

Understanding variation in biodiversity typically requires consideration of factors operating at different spatial scales. Recently, ecologists and biogeographers have recognized the need of analysing ecological communities in the light of multiple facets including not only species‐level information but also functional and phylogenetic approaches to improve our understanding of the relative contribution of processes shaping biodiversity. Here, our aim was to disentangle the relative importance of environmental variables measured at multiple levels (i.e., local, catchment, climate, and spatial variables) influencing variation in macroinvertebrate beta diversity facets (i.e., species, traits, and phylogeny) and their components (i.e., replacement and abundance difference) in boreal streams.

Taxon

Aquatic macroinvertebrates

Location

Western Finland

Methods

A total of 105 streams were sampled in western Finland, encompassing a geographical extent over 500 km. We analysed variation in the different beta diversity facets and components using distance‐based redundancy analysis and associated variation partitioning procedures. We modelled spatial structures using distance‐based Moran eigenvector maps.

Results

We found that the relative influence of explanatory variables on each diversity facet and component revealed relatively similar patterns. Our main finding was that local environmental and spatial variables generally contributed most to the total explained variability in all facets and components of beta diversity, whereas catchment and climate variables explained less variation in the beta diversity facets at the spatial scale considered in this study.

Main conclusions

Different facets of beta diversity were mainly influenced by local environmental variables and spatial structuring, likely acting through deterministic and stochastic pathways respectively. Identifying the ecological variables and mechanisms that drive variation in beta diversity may be used to guide the conservation and restoration efforts for biodiversity under global change.
Time trends in incidence and mortality of cutaneous melanoma in Germany
Authors: Garbe C. , Keim U. , Eigentler T. K. , Amaral T. , Katalinic A. , Holleczek B. , Martus P. , Leiter U.
Published: November 2018

Objectives

To characterize incidence and mortality trends of cutaneous melanoma (CM) in Germany to extrapolate these data until 2030.

Methods

We evaluated data from the Centre for Cancer Registry Data (1999–2012) and from the Saarland Cancer Registry (1970–2012). Age‐standardized (according to the European Standard Population, WHO 1976) incidence and mortality rates [age‐standardized incidence rates (ASIRs) and age‐standardized mortality rates (ASMRs)] and crude incidence and mortality rates [crude incidence rates (CIRs) and crude mortality rates (CMRs)] were analysed.

Results

In entire Germany, ASIRs increased by 55% to 19.2 and CIRs by 77% to 26.0 new cases per 100 000 from 1999 to 2012. ASMRs remained stable, whereas CMR increased by 58% to 4.1 for males and by 30% to 3.0 for females per 100 000. In the Federal State of Saarland, ASIRs increased more than four‐fold to 13.1, CIRs increased six–seven fold to 18.5/100 000 from 1970 to 2012. In the same period, ASMRs increased three‐fold in males and two‐fold in females to 2.5 and 1.6, whereas CMRs increased 5.5‐fold in males and 3.5‐fold in females to 3.9 and 3.2/100 000, mainly caused by steep increases of CIRs and CMRs in age groups ≥60 years. Projected CIRs will rise to 44–46 for males and 38–40 for females in 2030. Steepest increases were extrapolated for patients ≥60 years, especially for males, but are also expected for age groups of 40–59 years. In contrast, CIRs are anticipated to stabilize for subjects <40 years.

Conclusions

There is a constant increase in incidence and mortality rates for CM in Germany. As the German population is ageing and the current population has already accumulated high levels of UV exposure, a further increase in melanoma incidence is projected for the future without signs of levelling‐off.
Gender and age significantly determine patient needs and treatment goals in psoriasis – a lesson for practice
Authors: Maul J.‐T. , Navarini A.A. , Sommer R. , Anzengruber F. , Sorbe C. , Mrowietz U. , Drach M. , Blome C. , Boehncke W.‐H. , Thaci D. , Reich K. , von Kiedrowski R. , Körber A. , Yawalkar N. , Mainetti C. , Laffitte E. , Streit M. , Rustenbach S. , Conrad C. , Borradori L. , Gilliet M. , Cozzio A. , Itin P. , Häusermann P. , French L.E. , Radtke M.A. , Augustin M.
Published: November 2018

Background

Though patient needs are key drivers of treatment decisions, they are rarely systematically investigated in routine care.

Objective

This study aimed at analysing needs and expectations from the patient perspective in the German and Swiss psoriasis registries PsoBest and Swiss Dermatology Network of Targeted Therapies (SDNTT) with respect to treatment choice, age and gender.

Methods

The German and Swiss psoriasis registries observe patients recruited at first‐time use of systemic drugs. Within 10 years, clinical [Psoriasis Area Severity Index (PASI), Body Surface Area (BSA)] and patient‐reported outcomes are documented, including the Dermatology Quality of Life Index (DLQI) and the Patient Benefit Index (PBI), characterizing patient needs for treatment. The analysis data set includes n = 4894 patients from PsoBest and n = 449 from SDNTT with mean follow‐up time of 7.5 months.

Results

A total of 5343 patients registered between 2008 and 2016 were included in the analyses (at baseline: 59.6% male, mean age 47.6 years ± 14.5, PASI 14.2 ± 9.7, BSA 22.7 ± 19.7, DLQI 11.3 ± 7.2). The most important patient needs were to ‘get better skin quickly’ and to ‘be healed of all skin defects’.

Subgroup analyses by age revealed significant differences in needs, especially higher needs regarding social impairments in patients younger than 65 years. Patients 65 years or older attributed more importance to sleep quality, less dependency on medical visits, fewer side‐effects and confidence in the therapy. Out of 25 items reflecting patient needs, 20 items were rated significantly more important by women than men, with the greatest differences regarding feeling of depression, sleep quality and everyday productivity. Divided by treatment, needs were rated differently, recommending individualized and targeted choice of therapy.

Conclusion

Age and gender stratify patient needs. Women showed higher expectations and rated specific needs in psoriasis treatment higher than men. Analysing the patient needs on an individual level will facilitate shared decisions by patient and physician in finding the optimal personalized treatment.
Diversity of settlement‐stage reef fishes captured by light‐trap in a tropical south‐west Atlantic Ocean coastal reef system
Authors: Grande Henrique , Rezende Sergio de M. , Simon Thiony E. , Félix‐Hackradt Fabiana C. , García‐Charton José A. , Maida Mauro , Gaspar Ana L. B. , Francini‐Filho Ronaldo B. , Fredou Thierry , Ferreira Beatrice P.
Published: November 2018

This study reports the results of 5 years of monitoring reef fish post‐larvae using light traps in the Bay of Tamandaré, north‐east Brazil. An annotated checklist of pre‐settlement fish species, their frequency of occurrence and taxonomic characteristics are provided. In total, 4,422 post‐larval fishes belonging to 36 families, 56 genera and 76 species were captured. The most species‐rich families were Carangidae (7), Lutjanidae (6) and Pomacentridae (4), while the families Gerreidae (30.47%), Holocentridae (16.54%), Blenniidae (12.01%), Labrisomidae (8.36%), Lutjanidae (8.29%) and Acanthuridae (5.95%) were the most abundant. This is the first study of the taxonomic diversity and assemblage structure of settlement‐stage reef fishes in the tropical south‐west Atlantic Ocean. Although a few common species were not captured due to selectivity of light traps, the composition and taxonomic diversity of this first collection suggests that light traps are useful for studies of the early life history of a wide range of pre‐settlement reef fishes.
Reply to: Advance care planning requires training
Authors: Fulmer Terry , Escobedo Marcus , Berman Amy
Published: November 2018

This letter comments on the letters by Hammes et al
Black toes in two adolescents from the York Peninsula
Authors: Evans Louise , Sypek Scott , Lockie Fran
Published: November 2018

See Answer
Clinical presentation, diagnosis, treatment and outcome of spinal epidural empyema in four cats (2010 to 2016)
Authors: Guo S. , Lu D.
Published: November 2018

This case series reviews previous publications and reports four feline spinal epidural empyema cases that presented with non‐ambulatory thoracolumbar myelopathy. Two cats underwent myelography and two MRI. Bacteria were obtained in three cases, in two from epidural abscesses and from a tail base wound in one; histopathological examination of epidural tissue showed pyogranulomatous changes in the remaining cat. Three cats were treated by surgical decompression plus antimicrobial therapy and one cat was treated medically. All cats showed satisfactory improvement following treatment over a follow‐up period of 3 months. Spinal epidural empyema is a rare condition but all cats in this series had favourable outcomes.
A chromosome‐scale genome assembly reveals a highly dynamic effector repertoire of wheat powdery mildew
Authors: Müller Marion C. , Praz Coraline R. , Sotiropoulos Alexandros G. , Menardo Fabrizio , Kunz Lukas , Schudel Seraina , Oberhänsli Simone , Poretti Manuel , Wehrli Andreas , Bourras Salim , Keller Beat , Wicker Thomas
Published: November 2018

Blumeria graminis f. sp. tritici (B.g. tritici) is the causal agent of the wheat powdery mildew disease. The highly fragmented B.g. tritici genome available so far has prevented a systematic analysis of effector genes that are known to be involved in host adaptation. To study the diversity and evolution of effector genes we produced a chromosome‐scale assembly of the B.g. tritici genome.

The genome assembly and annotation was achieved by combining long‐read sequencing with high‐density genetic mapping, bacterial artificial chromosome fingerprinting and transcriptomics.

We found that the 166.6 Mb B.g. tritici genome encodes 844 candidate effector genes, over 40% more than previously reported. Candidate effector genes have characteristic local genomic organization such as gene clustering and enrichment for recombination‐active regions and certain transposable element families. A large group of 412 candidate effector genes shows high plasticity in terms of copy number variation in a global set of 36 isolates and of transcription levels.

Our data suggest that copy number variation and transcriptional flexibility are the main drivers for adaptation in B.g. tritici. The high repeat content may play a role in providing a genomic environment that allows rapid evolution of effector genes with selection as the driving force.
‘Acheronta movebo’
Authors: Yebra José M.
Published: November 2018

This paper addresses Naomi Alderman's The Power (2016), a (post‐)feminist dystopia where gender roles are reversed after what is called ‘the Cataclysm’. Being victims of male chauvinism, young girls develop the ability to emit an electrical charge through their hands, ‘the power’, which they use against their potential aggressors. One of these girls, Allie, uses it to start a violent female theocracy, not less violent and problematic than the patriarchy it fights against. The Power puts forward a stimulating debate on the justifiability and legitimacy of violence to combat violence. The novel, the paper contends, recasts the poetics and politics of 1990s cyberfeminism to meet new concerns, particularly the discourses of violence and otherness in the context of the twenty‐first‐century political crisis. To prove it, Rosie Braidotti's analysis of cyberfeminism is addressed first, to delve later into how The Power updates Slavoj Žižek's (Violence. London, UK: Profile Books, 2009), Walter Benjamin's (Selected writings. Vol. 1, 1913–1926. Cambridge, MA: Harvard University Press, 1996, pp. 249–251) and Hannah Arendt's (On violence, New York, NY: Harcourt, 1970; The origins of totalitarianism. New York, NY: Harcourt, 1976; On revolution. New York, NY: Penguin Books 1977) conceptions of violence and revolutionary rage.
Instability of BLOC‐2 and BLOC‐3 in Chinese patients with Hermansky‐Pudlak syndrome
Authors: Wei Aihua , Yuan Yefeng , Qi Zhan , Liu Teng , Bai Dayong , Zhang Yingzi , Yu Jiaying , Yang Lin , Yang Xiumin , Li Wei
Published: November 2018

Hermansky‐Pudlak syndrome (HPS) is a rare recessive disorder characterized by oculocutaneous albinism (OCA) or ocular albinism (OA), bleeding tendency, and other symptoms due to multiple defects in tissue‐specific lysosome‐related organelles. Ten HPS subtypes have been characterized with mutations in HPS1 to HPS10, which encode the subunits of BLOC‐1, ‐2, ‐3, and AP‐3. Using next‐generation sequencing (NGS), we have screened 100 hypopigmentation genes in OCA or OA patients and identified four HPS‐1, one HPS‐3, one HPS‐4, one HPS‐5, and three HPS‐6. The HPS‐4 case is the first report in the Chinese population. Among these 20 mutational alleles, 16 were previously unreported alleles (6 in HPS1, 1 in HPS3, 2 in HPS4, 2 in HPS5, and 5 in HPS6). BLOC‐2 and BLOC‐3 were destabilized due to the mutation of these HPS genes which are so far the only reported causative genes in Chinese HPS patients, in which HPS‐1 and HPS‐6 are the most common subtypes. The mutational spectrum of Chinese HPS is population specific.
Exposure of immature rat heart to antenatal glucocorticoid results in cardiac proliferation
Authors: Sakurai Kenzo , Osada Yosuke , Takeba Yuko , Mizuno Masanori , Tsuzuki Yoshimitsu , Ohta Yuki , Ootaki Masanori , Iri Taro , Aso Kentaro , Yamamoto Hitoshi , Matsumoto Naoki
Published: November 2018

Background

ATP synthesis and cardiac contraction‐related protein production are accelerated in the immature fetal heart by antenatal glucocorticoids (GC). This study investigated the structural maturity of the myocardium and underlying signal pathway associated with cardiac growth in fetal rats that received antenatal GC.

Methods and Results

Dexamethasone (DEX) was given to pregnant rats for 2 days from day 17 or day 19 of gestation, and the hearts of 19 and 21 day fetuses and 1‐day‐old neonates were analyzed. Although irregular myofibril orientation was observed morphologically in 19 day fetal hearts, the myofibril components were organized in fetuses after DEX. The cross‐sectional area of the myocardium and Ki‐67‐positive cells were significantly increased in fetal DEX groups, suggesting that cardiac enlargement resulted from myocyte proliferation. Glycogen synthase kinase‐3β (GSK‐3β) protein was significantly decreased in fetal DEX groups. β‐Catenin and vascular endothelial growth factor protein were also significantly increased. Furthermore, increased cardiomyocyte proliferation appeared to be mediated by GC receptors after culture with DEX in vitro.

Conclusions

Antenatal DEX induces structural maturity accompanying cardiomyocyte proliferation in the premature fetal rat heart, and GSK‐3β and β‐catenin are thought to contribute to cardiac growth.
Multiple Testing with the Structure-Adaptive Benjamini–Hochberg Algorithm
Authors: Li Ang , Barber Rina Foygel
Published: November 2018

In multiple-testing problems, where a large number of hypotheses are tested simultaneously, false discovery rate (FDR) control can be achieved with the well-known Benjamini–Hochberg procedure, which a(0, 1]dapts to the amount of signal in the data, under certain distributional assumptions. Many modifications of this procedure have been proposed to improve power in scenarios where the hypotheses are organized into groups or into a hierarchy, as well as other structured settings. Here we introduce the ‘structure-adaptive Benjamini–Hochberg algorithm’ (SABHA) as a generalization of these adaptive testing methods. The SABHA method incorporates prior information about any predetermined type of structure in the pattern of locations of the signals and nulls within the list of hypotheses, to reweight the p-values in a data-adaptive way. This raises the power by making more discoveries in regions where signals appear to be more common. Our main theoretical result proves that the SABHA method controls the FDR at a level that is at most slightly higher than the target FDR level, as long as the adaptive weights are constrained sufficiently so as not to overfit too much to the data—interestingly, the excess FDR can be related to the Rademacher complexity or Gaussian width of the class from which we choose our data-adaptive weights. We apply this general framework to various structured settings, including ordered, grouped and low total variation structures, and obtain the bounds on the FDR for each specific setting. We also examine the empirical performance of the SABHA method on functional magnetic resonance imaging activity data and on gene–drug response data, as well as on simulated data.
Extreme aridity prior to lake expansion deciphered from facies evolution in the Miocene Ili Basin, south‐east Kazakhstan
Authors: Frisch Konstantin , Voigt Silke , Voigt Thomas , Hellwig Alexandra , Verestek Verena , Weber Yuki
Published: November 2018

Central Asia witnessed progressive aridification during the Miocene, commonly related to mountain uplift, the Paratethys retreat and global climate cooling. However, the formation of Miocene lakes in Central Asia seems to oppose drier conditions, suggesting that the precise timing, extent and forcing of the aridification is still not well constrained. This study presents a facies model for the alluvial–lacustrine part of the Middle to Late Miocene of the Ili Basin, obtained from two successions. The model enables the semi‐quantitative assessment of regional water level and salinity, and characterizes the control of water level on evaporite formation and diagenesis. Both the proximal Kendyrlisai and the distal Aktau successions show an overall increase in water availability from dry mudflat deposits to lacustrine sedimentation with a transitional playa phase. Increasing evaporation rates outpaced the water supply and caused groundwater salinization. Subsequent lake expansion coincided with a basin‐wide desalinization and required a shift to a positive water budget. A climatic control of the hydrological evolution is inferred due to abrupt salinization and a minor tectonic influence. The long‐term water accumulation is probably related to the hydrological closure of the basin in the early Middle Miocene (15·3 Ma). Starting at 14·3 Ma, the step‐wise salinization occurred simultaneously with the global cooling of the Miocene Climate Transition. The Miocene Climate Transition led to extreme aridity in the Ili Basin, highlighted by the early diagenetic formation of displacive anhydrite in the basin centre. The expansion of the freshwater lake (12·7 to 11·5 Ma) was possibly promoted by lower evaporation rates due to decreasing air temperatures in the Ili Basin after the Miocene Climate Transition. The extreme aridity in the Ili Basin is interpreted as a continental counterpart to the Badenian Salinity Crisis in the Central Paratethys. This emphasizes the role of atmospheric forcing on evaporite sedimentation across Eurasia during the Middle Miocene.
The influence of turbidity currents and contour currents on the distribution of deep‐water sediment waves offshore eastern Canada
Authors: Normandeau Alexandre , Campbell D. Calvin , Cartigny Matthieu J. B.
Published: November 2018

Sediment waves are commonly observed on the sea floor and often vary in morphology and geometry according to factors such as seabed slope, density and discharge of turbidity currents, and the presence of persistent contour currents. This paper documents the morphology, internal geometry and distribution of deep‐water (4000 to 5000 m) bedforms observed on the sea floor offshore eastern Canada using high‐resolution multibeam bathymetry data and seismic stratigraphy. The bedforms have wavelengths of >1 km but fundamentally vary in terms of morphology and internal stratigraphy, and are distinguished into three main types. The first type, characterized by their long‐wavelength crescentic shape, is interpreted as net‐erosional cyclic steps. These cyclic steps were formed by turbidity currents flowing through canyons and overtopping and breaching levées. The second type, characterized by their linear shape and presence on levées, is interpreted as net‐depositional cyclic steps. These upslope migrating bedforms are strongly aggradational, indicating high sediment deposition from turbidity currents. The third type, characterized by their obliqueness to canyons, is observed on an open slope and is interpreted as antidunes. These antidunes were formed by the deflection of the upper dilute, low‐density parts of turbidity currents by contour currents. The modelling of the behaviour of these different types of turbidity currents reveals that fast‐flowing flows form cyclic steps while their upper parts overspill and are entrained westward by contour currents. The interaction between turbidity currents and contour currents results in flow thickening and reduced sediment concentration, which leads to lower flow velocities. Lower velocities, in turn, allow the formation of antidunes instead of cyclic steps because the densiometric Froude number (Fr′) decreases. Therefore, this study shows that both net‐erosional and net‐depositional cyclic steps are distributed along channels where turbidity currents prevail whereas antidunes form on open slopes, in a mixed turbidite/contourite system. This study provides insights into the influence of turbidity currents versus contour currents on the morphology, geometry and distribution of bedforms in a mixed turbidite–contourite system.
Measuring epidermal effects of ostomy skin barriers
Authors: Grove Gary , Houser Tim , Sibbald Gary , Salvadalena Ginger
Published: November 2018

Background

Ostomy barriers are adhesive devices designed to hold pouching systems to the abdomen and protect the peristomal skin from stoma effluent. The objective of this study was to determine differences in the extent of skin trauma resulting from serially applying and removing two types of ostomy barriers.

Methods

The study was a randomized, prospective, repeated measure trial involving healthy volunteers. The ostomy skin barriers were applied to the abdomen and changed every 3‐4 days over a 17‐day period. Skin observations (erythema, stripping, edge irritation and overall comparisons) were completed by a trained (blinded) observer. Transepidermal water loss (TEWL) measurements were completed by a separate (blinded) technician. TEWL was measured in a designated site and again in the most visually traumatized location at termination.

Results

Statistically significant differences were found between the two test devices in all assessments but visual observation of erythema. Highly significant differences in TEWL were found between the test products when measured at termination from the most visually traumatized sites.

Conclusions

The ostomy barrier with ceramide was significantly less disruptive to the epidermis than the ostomy barrier without ceramide. TEWL measurements were more sensitive to changes in the barrier function of the skin than visual observation of erythema.
Three-Dimensional Visualization of Flow Characteristics Using a Magnetic Resonance Imaging in a Lattice Cooling Channel
Authors: Tsuru Tomoko , Ishida Katsuhiko , Fujita Junya , Takeishi Kenichiro
Published: November 2018

Flow structures in lattice cooling channels are investigated experimentally by measuring three-dimensional (3D) velocity components over entire duct. The lattice cooling structure is formed by crossing two sets of parallel inclined ribs. Heat transfer is enhanced when coolant flows through the narrow subchannels between the ribs. According to the past literature, longitudinal vortex structures are formed inside the subchannels due to interactions between crossing flows. In this study, 3D velocity field measurement is performed using magnetic resonance imaging (MRI) scanner to clarify the flow mechanism. The rib inclination angle is varied from 30 to 60 deg. Reynolds number is set at approximately 8000 based on the whole duct inlet hydraulic diameter and bulk velocity. Working fluid is 0.015 mol/L copper sulfate aqueous solution. Measured results show that coolants in the upper and lower subchannels interact not only at the both ends of the duct, but also at diamond-shaped openings formed by opposite subchannels. The exchange of momentum between the upper and lower subchannels occurs at the openings, leading to sustained longitudinal vortex in each subchannel as mentioned in the literature. When the ribs are arranged with obtuse angle, a large vortex spreads across the contact surface, while the vortex structure independently stays in each subchannel for acute rib angle. The measured velocity fields are compared with numerically-simulated ones using a Reynolds-averaged Navier-Stokes (RANS) solver. Overall flow pattern is captured, but flow interaction between the upper and lower subchannels is underestimated.
Investigation of Thermal Effect on Bypass Transition on a High-Pressure Turbine Guide Vane
Authors: Cação Ferreira Tânia S. , Vasilakopoulos Nikolaos , Arts Tony
Published: November 2018

The role of gas-to-wall temperature ratio on bypass transition along a highly loaded turbine guide vane is investigated through time-resolved heat flux measurements for different flow conditions. The tests are conducted in the von Karman Institute (VKI) isentropic compression tube (CT-2) facility. High response thin films mounted on the vane (VKI LS89 airfoil) coupled with analog circuits are used for the heat flux measurements. The first detectable wall heat flux fluctuations denote the onset of transition which is also evaluated by both the heat transfer coefficient and the intermittency factor distributions along the suction side. The exit Mach number is kept constant during each test by means of a downstream sonic throat while the gas-to-wall temperature ratio is varied from 1.14 to 1.51 by changing the inlet gas temperature. Four test cases are considered for different exit Mach numbers (0.52 and 0.86) and freestream turbulence intensity levels (0.8% and 5.3%) while the isentropic exit chord Reynolds number is maintained at 106. In the present test campaign, the length and the evolution of the phenomenon indicate a measurable effect of the gas-to-wall temperature ratio for test cases with mild pressure gradients.
Nonlinear Dynamics of Composite Laminated Circular Cylindrical Shell With Membranes in Thermal Environment
Authors: Liu Tao , Zhang Wei , Zhang Yufei , Wang Qian
Published: November 2018

This paper is focused on the chaotic dynamics of a composite laminated circular cylindrical shell with radially pre-stretched membranes at both ends and clamped along a generatrix. Based on the two-degree-of-freedom non-autonomous nonlinear equations of this system, the method of multiple scales is employed to obtain the four-dimensional nonlinear averaged equation. The resonant case considered here is the primary parametric resonance-1/2 subharmonic resonance and 1:1 internal resonance. Corresponding to several selected parameters, the periodic and chaotic motions of the composite laminated circular cylindrical shell clamped along a generatrix are demonstrated by the bifurcation diagrams, the maximum Lyapunov exponents, the phase portraits, the waveforms, the power spectrums and the Poincaré map. The temperature parameter excitation shows that the Pomeau-Manneville type intermittent chaos occur under the certain initial conditions. It is also found that there exist the twin phenomena between the Pomeau-Manneville type intermittent chaos and the period-doubling bifurcation.
Vibration Analysis of a Roller Bearing With a Bump Defect
Authors: Shi Zhifeng , Liu Jing , Chen Zaigang , Shao Yimin
Published: November 2018

Vibration performances of roller bearings are greatly affected by various localized defects. Thus, it is very important to analyze vibration characteristics of the roller bearings with the localized defects. In this paper, a nonlinear dynamic model is developed to formulate the effect of a localized defect on the vibration characteristics of a cylindrical roller bearing (CRB). A bump defect is formulated in this model. The defect profile is defined as a spherical one. The time-varying displacement excitation caused by the defect is modelled. Effects of the defect sizes on the vibration characteristics of the roller bearing are discussed. The simulation results show that the developed method can provide some guidance for understanding the vibration characteristics of the CRB with a bump defect.
Free Vibration Characteristic of a Rotating Cantilever Beam With Tip Mass
Authors: Xie Kai , Abbas Laith K. , Chen Dongyang , Rui Xiaoting
Published: November 2018

In many cases, vibration is a serious problem, undesirable, wasting energy and creating unwanted sound. Transfer Matrix Method for Multibody Systems (MSTMM) is one of the sophisticated methods that can be used efficiently to (1) Model large systems with a large number of subsystems and rigid-flexible structures, and (2) Calculate the vibration characteristics and dynamic responses of the multibody systems. The size of matrices in MSTMM remains small regardless of the number of elements in the model. Having smaller matrix sizes helps to have less computational expense leading to a faster answer. Based on the MSTMM advantages, vibration characteristic of a rotating cantilever beam with an attached tip mass is modeled and simulated in the present paper while the beam undergoes flapwise vibration. This system can be thought of as an extremely simplified model of a helicopter rotor blade or a blade of an auto-cooling fan. The overall transfer equation in the MSTMM context only involves boundary state vectors, whereas the state vectors at all other connection points do not appear. The state vectors at the boundary include the displacements, rotation angles, bending moments and shear forces. These are partly known and partly unknown. The eigenvalue problem is solved by using Frobenius method of solution in power series. Recursive eigenvalue search algorithm is used to determine the system frequencies. Numerical examples are performed to validate with those published in the literature and produced by Workbench ANSYS.
Multi-Objective Topological Optimization of Support Frame for High-Speed and Heavy-Load Triangle Track Wheel Based on Analytic Hierarchy Process
Authors: Wu Fenghe , Wang Zhaohua , Sun Yinxu , Yang Yulin , Li Yongxin , Guo Baosu , Peng Qingjin
Published: November 2018

The high-speed, heavy-load and changeable triangle track wheel is a motion device that can carry out interchange between the track wheel and tire in an ordinary vehicle. The topology optimization for the support frame can reduce weight and improve the maneuverability of the vehicle. However, it is difficult to consider simultaneously its weight, stiffness and modal in the process of the structure optimization. Thus, a topology optimization method for multi-objective and multi-working-condition is proposed based on the AHP (analytic hierarchy process) and average frequency method. Firstly, considering the static multi-stiffness target and dynamic vibration frequency target, using the compromise programming method and average frequency method, the objective function of the multi-objective and multi-working-condition topology optimization is established. Then, based on the optimization target, design criteria and indexes, the lightweight hierarchical structure model of the support frame consisting of three levels and eight weight factors is established. Values of 8 weight coefficients of the multi-objective topology optimization are determined through solving the weight factor judgment matrix. Finally, considering the multi-working-condition, taking the minimum objective function of the static and dynamic characteristics as target, and the volume ratio is 50% as boundary, the mathematical model of the topology optimization is established. Simulation results show that the stiffness and strength of the support frame are improved respectively by 74.3% and 1.3% while its weight is reduced by 16.3%. This method also provides a new way to the lightweight design for other large, heavy and multi-condition equipment.
A Testing Method for the Prediction of Comfort of City Bicycles
Authors: Doria Alberto , Marconi Edoardo
Published: November 2018

An experimental/numerical method for predicting bicycle comfort from laboratory tests is presented. The frequency response functions of the seat post and of the handlebar stem are measured by means of impulsive excitation applied on vibrating tables placed under the front and rear wheel. The interference between front and rear excitation, which occurs on the road, is taken into account by numerically calculating the correlated frequency response function. Numerical calculations based on the concept of vehicle mission make it possible to manage the dependence of acceleration on forward speed and to calculate acceleration indexes. Results obtained with 2 bicycles and 3 levels of inflation pressure show the validity of the method.
Performance Enhancement of Pneumatic Vibration Isolators Using Self-Tuning PID Feedback and Time-Delay-Control (TDC)-Based Feedforward Scheme
Authors: Liang Jin-Wei , Chen Hung-Yi , Zeng Lyu-Cyuan
Published: November 2018

A hybrid control scheme that combines a self-tuning PID-feedback loop and TDC-based feedforward scheme is proposed in this study to cope with an active pneumatic vibration isolator. In order to establish an effective TDC feedforward control a reliable mathematical model of the pneumatic isolator is required and developed firstly. Numerical and experimental investigations on the validity of the mathematical model are performed. It is found that although slight discrepancy exists between predicted and observed behaviors of the system, the overall model performance is acceptable. The resultant model is then applied in the design of the TDC feedforward scheme. A neuro-based adaptive PID control is integrated with the TDC feedforward algorithm to form the hybrid control. Numerical and experimental isolation tests are carried out to examine the suppression performances of the proposed hybrid control scheme. The results show that the proposed hybrid control method outperforms solely TDC feedforward while the latter outperforms the passive isolation system. Moreover, the proposed hybrid control scheme can suppress the vibration near the system’s resonance.
Model Validation in Early Phase of Designing Complex Engineered Systems
Authors: Keshavarzi Elham , Goebel Kai , Tumer Irem Y. , Hoyle Christopher
Published: November 2018

In design process of a complex engineered system, studying the behavior of the system prior to manufacturing plays a key role to reduce cost of design and enhance the efficiency of the system during its lifecycle. To study the behavior of the system in the early design phase, it is required to model the characterization of the system and simulate the system’s behavior. The challenge is the fact that in early design stage, there is no or little information from the real system’s behavior, therefore there is not enough data to use to validate the model simulation and make sure that the model is representing the real system’s behavior appropriately. In this paper, we address this issue and propose methods to validate the model developed in the early design stage. First we propose a method based on FMEA and show how to quantify expert’s knowledge and validate the model simulation in the early design stage. Then, we propose a non-parametric technique to test if the observed behavior of one or more subsystems which currently exist, and the model simulation are the same. In addition, a local sensitivity analysis search tool is developed that helps the designers to focus on sensitive parts of the system in further design stages, particularly when mapping the conceptual model to a component model. We apply the proposed methods to validate the output of failure simulation developed in the early stage of designing a monopropellant propulsion system design.
Automatic Fault Tree Generation From Multidisciplinary Dependency Models for Early Failure Propagation Assessment
Authors: Papakonstantinou Nikolaos , Linnosmaa Joonas , Alanen Jarmo , O'Halloran Bryan
Published: November 2018

Safety engineering for complex systems is a very challenging task and the industry has a firm basis and trust on a set of established methods like the Probabilistic Risk Assessment (PRA). New methodologies for system engineering are being proposed by academia, some related to safety, but they have a limited chance for successful adoption by the safety industry unless they provide a clear connection and benefit in relation to the traditional methodologies. Model-Based System Engineering (MBSE) has produced multiple safety related applications. In past work system models were used to generate event trees, failure propagation scenarios and for early human reliability analyses. This paper extends previous work, on a high-level interdisciplinary system model for early defense in depth assessment, to support the automatic generation of fault tree statements for specific critical system components. These statements can then be combined into fault trees using software already utilized by the industry. The fault trees can then be linked to event trees in order to provide a more complete picture of an initiating event, the mitigating functions and critical components that are involved. The produced fault trees use a worst-case scenario approach by stating that if a dependency exists then the failure propagation is certain. Our proposed method doesn’t consider specific failure modes and related probabilities, a safety expert can use them as a starting point for further development. The methodology is demonstrated with a case study of a spent fuel pool cooling system of a nuclear plant.
Multiple Modalities, Sensoriums, Experiences in Blended Spaces With Toolness and Tools for Conceptual Design Engineering
Authors: Wendrich Robert E.
Published: November 2018

This paper asserts that, visual and meta-cognitive stimuli constructed from multiple experiences and multiple modalities in ‘blended spaces’ (i.e. internal or external), are potential stimuli in ideation, iterative, and creative conceptual design engineering processes. These multiplicities in human capabilities are intertwined, interlinked, and/or coupled with the cognitive memory patterns from mental representations (i.e. abstractions) of productive thought. Ideas are inherently ambiguous and/or spatial representations that become tangible- and visual transformations through intention, interaction and externalization.
An Approach for Building Product Use-Case Scenarios in Different Virtual Reality Systems
Authors: Mahboob Atif , Husung Stephan , Weber Christian , Liebal Andreas , Krömker Heidi
Published: November 2018

During the product development process, it is of great importance to consider the later life phase situations of a product. This includes the interaction of the product with its environment and the human actor(s) in its different life phases. Therefore, an early evaluation of a product and its later life phase interactions are of great value. Virtual Reality (VR) technology is seen as very important at this point, as it can help the designer to realize the later life phase situations of a product inside VR. However, the preparation of VR-scenes remains a difficult task, as it requires a great amount of time and effort. Furthermore, the current methods for the preparation of such scenes offer very limited reusability.

This paper will focus on an existing method that uses Model Based Systems Engineering (MBSE) to describe the VR-scene for a CAVE-type VR-system. This method will be further extended and an improvement to the existing modeling approach will be presented to achieve a faster simulation in VR and reusability of VR-scenes. Furthermore, a detailed comparison of the conventional and the new approach will be presented. The new approach enables a faster simulation that will be validated by comparing the execution speed of both approaches under the modeling approach section. The reusability perspective of the prepared VR-scene will also be discussed.

A Head Mounted Display (HMD), in comparison with CAVE type VR-systems, offers a cost reduction in the use of VR technology. This paper will also provide the idea for achieving a simulation in HMD while using the same MBSE-approach used for CAVE type VR-systems. The flow of information for simulation in HMD and the idea of implementation will be presented in detail.
Workspace Analysis and the Effect of Geometric Parameters for Parallel Mechanisms of the N-UU Class
Authors: Shah Divya , Metta Giorgio , Parmiggiani Alberto
Published: November 2018

N-UU class mechanisms, exemplified by the Omni-Wrist III, are compact parallel kinematic mechanisms (PKM) with large singularity free workspaces. These characteristics make them ideal for applications in robot wrists. This article presents the detailed kinematic and workspace analysis for four N-UU class mechanisms. More in detail, the equations defining the mechanism’s moving platform kinematics are derived as a function of the motion of the input links; these are then used to explore the mechanism’s workspace. These results are furthermore validated by comparing them to the results obtained from CAD-based simulations.

The analyses suggests that the workspace of the mechanism is non-uniform, with a “warping” behaviour that occurs in an asymmetric fashion in a specific region of the workspace. Furthermore we show how the rotation of the input links, which mainly actuates the yaw and pitch angles of the mechanism, also causes unwanted coupled rotations along the roll axis.
Design Exploration of Reliably Manufacturable Materials and Structures With Applications to a Microstereolithography System
Authors: Morris Clinton , Seepersad Carolyn C.
Published: November 2018

One of the challenges in designing for additive manufacturing (AM) is accounting for the differences between as-designed and as-built geometries and material properties. From a designer’s perspective, these differences can lead to degradation of part performance, which is especially difficult to accommodate in small-lot or one-of-a-kind production. In this context, each part is unique, and therefore, extensive iteration is costly. Designers need a means of exploring the design space while simultaneously considering the reliability of additively manufacturing particular candidate designs. In this work, a design exploration approach, based on Bayesian network classifiers (BNC), is extended to incorporate manufacturability explicitly into the design exploration process.

The example application is the design of negative stiffness (NS) metamaterials, in which small volume fractions of negative stiffness (NS) inclusions are embedded within a host material. The resulting metamaterial or composite exhibits macroscopic mechanical stiffness and loss properties that exceed those of the base matrix material. The inclusions are fabricated with microstereolithography with features on the scale of tens of microns, but variability is observed in material properties and dimensions from specimen to specimen.

In this work, the manufacturing variability of critical features of a NS inclusion fabricated via microstereolithography are characterized experimentally and modelled mathematically. Specifically, the variation in the geometry of the NS inclusions and the Young’s modulus of the photopolymer are measured and modeled by both nonparametric and parametric joint probability distributions. Finally, the quantified manufacturing variability is incorporated into the BNC approach as a manufacturability classifier to identify candidate designs that achieve performance targets reliably, even when manufacturing variability is taken into account.