bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing Homogenization Heat Treatment of Al-Zn-Mg-Cu-Zr-0.15Er Alloy
Authors: Wang Yue Qi , Huang Hui , Wen Sheng Ping , Gao Kun Yuan , Wang Yue , Zhang Ping Ping , Rao Mao , Wang Zheng An , Nie Zuo Ren
Published: April 2015

The effects of the homogenization conditions on the microstructure of Al-Zn-Mg-Cu-Zr-0.5Er alloy were investigated by differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). The results showed that a lot of coarse phases existed in as-cast Al-Zn-Mg-Cu-Zr-0.5Er alloy. The dissolvable phases at grain boundary consisted of Mg32(Al, Zn)49. The residual phases dissolved into the matrix gradually during homogenization with increasing temperature and prolonging holding time. When the temperature increased to 465°C, and time prolongs to 24h, the main phase disappeared except the Fe and Er enriched phase, as a result of its high melting temperature. Taking into account the precipitation of Al3Er, we used a two-step homogenization .Hence, the optimum parameters of homogenization were 400 °C for 4 h and 465 °C for 24 h, which are good for the presence of coherent, elastically hard and nanosized Al3(Er, Zr) particles and the dissolvable coarse phases .
Robust Design of UOE Forming Process Based on Support Vector Machine
Authors: Zou Tian Xia , Wu Guang Han , Li Da Yong , Ren Qiang , Peng Ying Hong
Published: April 2015

Fluctuations in material properties of the incoming steel for UOE forming process are widespread. According to the statistics, the fluctuation range of the yield strength of the same grade pipeline steel is around 80MPa. Robust optimization methods have been widely applied in sheet metal forming area. In this paper, experiments were conducted to investigate how a stochastic material behavior of noise factors affected UOE forming quality. Robust design models integrated with response surface method for UOE forming process were established to minimize impact of the variations and improve the qualified rate of UOE pipe ovality. Support vector machine in both classification and regression was adopted to map the relation between input process parameters and forming qualities. The deterministic and robust optimization results are presented and compared, demonstrating increased process robustness and decreased number of product rejects by application of the robust optimization approach.
The Extrusion Cracks of Inconel 625 Superalloy Tubes Caused by the Primary MC Carbides
Authors: Guo Qing Miao , Tang Zhen Lei , Xie Guo Liang , Hu Jie , Li De Fu
Published: April 2015

Inconel 625 superalloy tubes were hot extruded using a horizontal extruder. Optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) technique were employed to investigate the extrusion defects mainly caused by the primary MC carbides. The results showed that a lot of surface cracks, internal cracks, grooves and shrinkage cavity defects existed in the outer surface and internal of the Inconel 625 superalloy tube after hot extrusion. However, the inner surface of the tube was smooth and no cracks were observed. In addition to the external factors during hot extrusion, the cracks are mainly caused by the primary MC carbides or large dimension of C particles formed due to a relatively short smelting time and large dimension of C particles during smelting with the decreasing plasticity of the grain boundary. This kind of cracks can be avoided through improving the uniformity of the chemical composition by reducing the size of C particles and extending the diffusion time during the smelting of Inconel 625 superalloy.
Effect of Porosity on Mechanical Properties of Ti-5Al-2.5Sn ELI Alloy from Atomized Powder
Authors: Xu Lei , Guo Rui Peng , Yang Rui
Published: April 2015

Ti-5Al-2.5Sn ELI alloy is a typical α titanium, which is widely used at cryogenic temperatures. Hot isostatic pressing (HIPing) is a common technology to fabricate powder metallurgy (P/M) titanium alloys and components. Porosity control is very crucial for P/M alloys during application, and porosity will deteriorate mechanical properties of P/M alloys. In this study, porosity caused by HIPing process has been investigated. Effects of porosity on metallurgy quality of P/M Ti-5Al-2.5Sn ELI alloy have been accessed. The results showed that when porosity levels was less than 0.6%, no significant difference was found comparing with full dense P/M Ti-5Al-2.5Sn ELI alloy. Near-net-shape forming processes of P/M titanium alloy parts ware studied. By using metal capsules and metal internal tooling, near-net-shaping of P/M parts with complex shapes was demonstrated.
Microstructure Evolution at the Diffusion Bonding Interface of High Nb Containing TiAl Alloy
Authors: Qi Xian Sheng , Xue Xiang Yi , Tang Bin , Wang Chuan Yun , Kou Hong Chao , Li Jin Shan
Published: April 2015

A series of diffusion bonding tests were conducted on high Nb containing TiAl alloy with duplex microstructure, the evolution of microstructure at bonding interface was investigated. Bonding process was performed by using vacuum hot press furnace at the temperature range from 850 to 1150°C with the pressure of 30MPa for 45min. The microstructure observation indicates that sound joint without unbounded area can be obtained when bonded above 950°C. Recrystallization happens in bonding interface when bonded at 1150°C and the recrystallized grain prior nucleated at bonding interface between the lamella colonies. Nucleation and growth of recrystallized grains promote migration of bonding interface and thus improve bonding quality. Besides, the post-bonding heat treatment (PBHT) was also performed to promote the evolution of bonding interface. The experimental results reveal that the bonding interface disappears after PBHT at 1135°Cfor 12h, and exhibits near gamma microstructure.
Simulation of Container Design for Powder Metallurgy Titanium Components through Hot-Isostatic-Pressing
Authors: Guo Rui Peng , Xu Lei , Wu Jie , Lu Zheng Guan , Yang Rui
Published: April 2015

Shima model and two different kinds of container designs were described. The final geometries of powder metallurgy (PM) preforms were predicted by using finite element method. Several PM Ti-6Al-4V parts were fabricated through a hot isostatic pressing route for comparison with the prediction from the modelling. FEM simulation can be used for shrinkage prediction of powder during HIPing process. The finite element calculations agreed well with the experimental data for shrinkage of the titanium alloy powder under HIPing. The simulation results is helpful to fabricate near-net-shape PM titanium parts.
Deformation-Induced Solid-State Amorphization in a Nanostructured Al-Mg Alloy Processed by High Pressure Torsion
Authors: Liu Man Ping , Xie Xue Feng , Zhang Zhen Ya , Wang Hui , Roven Hans J.
Published: April 2015

This work reports the experimental evidence of localized solid-state amorphization (SSA) in a nanostructured Al–Mg alloy processed by high pressure torsion at room temperature. Electron backscatter diffraction analysis indicated that the deformed alloy had a very small average grain size of about 79 nm. High-resolution transmission electron microscopy (HRTEM) observations illustrated that the deformation-induced SSA were frequently located in the vicinity of grain boundaries (GBs) and GB junctions where high density dislocations, severe lattice distortion, deformation twins and stacking faults coexisted in the deformed alloy. The SSA phenomenon may primarily be attributed to the strong interactions of the high dislocation densities, GBs and the planar interfaces. A possible formation process of amorphization is proposed based on the HRTEM investigations. The present results suggest that the crystalline-to-amorphous transformation could also occur in binary Al–Mg alloys through severe plastic deformation that are usually produced by rapid solidification.
A Temperature Field Analysis for Contraction and Collapse of 72AU2 Hot-Rolled Steel
Authors: Hu Han Jiang , Zhao Ai Min
Published: April 2015

Hot rolled coil after winding cooled to room temperature in the storage room often takes 4 to 5 days. The process of coil cooling sometimes produces collapse defects in industrial applications. In this research, the cooling process after coiling of Shougang Group 72AU2 hot-rolled strip steel was taken as the research material. We used finite element method (FEM) software ABAQUS to analyze the temperature field of coil after coiling. At first, a temperature field model of hot-rolled coil during cooling was established by the finite element method. The simulation results show that, the maximum temperature difference is 206°C, when the cooling-time is about 50th min. The highest temperature node was about at 44% apart from inside diameter distance position in the thickness direction, and finally moved to the node which is at 26% apart from inside diameter distance position. Temperature field calculation considered the anisotropy of the heat transfer. The temperature of each node can be obtained by this simulation, which cannot be obtained from field measurements and experiments. Thereby this research has a significant impact on further research on the causes of the contraction and collapse.
Research and Preparation of Silver Free Amorphous Active Brazing Alloy
Authors: Fang Wei Ping , Yi Yao Yong , Liu Feng Mei , Liu Zheng Lin , Deng Zhen Hua
Published: April 2015

A silver free amorphous Cu-35Ti-12Ni active brazing alloy was successfully prepared in this work. The crystallinity, microstructure, and chemical composition were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive spectrometry (EDS), respectively. A typical characteristic peak of amorphous material was observed in the XRD pattern. The microstructures and chemical compositions of the silver free amorphous alloy were uniform. Differential scanning calorimetry (DSC) result shows that the amorphous silver free brazing alloy has higher melting temperature than commercial silver brazing alloy (Ag-26.5Cu-1.5Ti). Wetting contact angle and spreading area on Si3N4 ceramic substrate were used to evaluate the wetting ability of brazing alloy. The wetting angle was smaller than 5o, and the spreading area was 141.6 mm2 at 1100°C. The bending strength of silver free brazing alloy/Si3N4 was also carried out. The mechanical test shows that the amorphous Cu-35Ti-12Ni/Si3N4 has higher joint strength (304.7MPa) than the crystal Cu-35Ti-12Ni/Si3N4 (294.7MPa) at room temperature.
Embracing a vision of the New Jerusalem (Rv 21:1−22:5) to impact on life and society
Authors: Pohlmann Martin H.
Published: April 2015

Apocalyptic biblical literature has played a significant role in motivating and mobilising Christians. As part of this genre, the Apocalypse of John has played this mobilising role within the church throughout its history. Jerusalem is often incorporated into this genre to conjure up different emotions and images to impact many different people. For example, the Jew annually recites the words to fellow Jews at every Passover meal: ‘Next year in Jerusalem’. Most Christians know the hymn ‘The holy city’, originally penned by Frederic Weatherly in 1892. It lifts many a spirit as it conjures up the idea of a beautiful, perfect, heavenly city of God. However, there is more to this apocalyptic vision, which will be explored in this article. The city upholds the hope of decent godly living today. Whilst Jerusalem is a city with an extremely chequered history, it remains to be the launching pad of a dream that believers can embrace in order to impact society for the better. The vision in Revelation 21–22 is the launch of the ‘idea’ of God’s intention for society today, and the ‘implementation impetus’ is the primary role of the church. In the greater scheme of things, the world community is the target group for a better society for everyone.Aanneming van ’n visioen van die Nuwe Jerusalem (Op 21:1–22:5) ten einde ’n invloed op lewe en die samelewing uit te oefen. Apokaliptiese Bybelliteratuur het ’n beduidende rol in die motivering en aansporing van Christengemeenskappe gespeel. Die Openbaring van Johannes het hierdie motiveringsrol deurgaans in die geskiedenis van die kerkas deel van dié genre vertolk. Jerusalem is dikwels hierby ingesluit om ’n verskeidenheid van emosies en beelde op te roep ten einde ’n impak op ’n verskeidenheid mense te maak. Die Jood, byvoorbeeld, haal jaarliks die volgende woorde teenoor mede-Jode tydens die Paasmaaltyd aan: ‘Volgende jaar in Jerusalem’. Die meeste Christene ken die gesang ‘The holy city’ wat oorspronklik deur Frederic Weatherly in 1892 geskryf is. Dit hef menige gelowiges se gemoedere op omdat dit die beeld van ’n pragtige, perfekte stad van God oproep. Daar is egter meer aan hierdie openbaringsuitsig wat in hierdie artikel verder ondersoek word. Die hemelstad bekragtig die hoop vir ’n godvrugtige lewe vandag. Alhoewel Jerusalem ’n stad met ’n uiters veelbewoë geskiedenis is, is dit tog die beginpunt vir hierdie droom van gelowiges om die samelewing te verbeter. Die visioen in Openbaring 21–22 is die bekendstelling van die ‘idee’ van God se bedoeling vir ons hedendaagse samelewing en die ‘vervullende beweegkrag’ is die primêre rol van die kerk. Holisties beskou, is die wêreldgemeenskap die teikengroep vir ’n beter samelewing vir almal.
Stratigraphic and temporal context and faunal diversity of Permian-Jurassic continental tetrapod assemblages from the Fundy rift basin, eastern Canada
Authors: Sues Hans-Dieter , Olsen Paul Eric
Published: April 2015

The Fundy basin in Nova Scotia and New Brunswick is the largest exposed rift basin of the Newark Supergroup and also extends beneath the Bay of Fundy. Its strata can be divided into four tectonostratigraphic sequences (TS). TS I is represented by the probably Permian Honeycomb Point Formation and possibly the Lepreau Formation. TS II includes the Wolfville Formation with the probably Middle Triassic Economy Member and the early Late Triassic Evangeline Member. These members have yielded markedly different assemblages of continental tetrapods. TS III comprises most of the Blomidon Formation, which is Norian to Rhaetian in age. The Blomidon Formation has yielded few skeletal remains of tetrapods to date but many tetrapod tracks. TS IV includes the late Rhaetian top of the Blomidon Formation and the McCoy Brook Formation, which overlies the North Mountain Basalt and is latest Rhaetian and earliest Jurassic (Hettangian) in age. The McCoy Brook Formation has yielded a diversity of continental tetrapods and lacks any of the characteristic Late Triassic forms. Recent work has correlated the Global Boundary Stratotype Section and Point (GSSP) for the base of the Jurassic (Hettangian) to a level well above the North Mountain Basalt. Thus most of the tetrapod fossils from the McCoy Brook Formation are latest Rhaetian in age, but the higher horizon with skeletal remains of sauropodomorph dinosaurs may be earliest Hettangian in age. The Fundy basin preserves the only known, stratigraphically tightly constrained record of the profound biotic changes in continental ecosystems across the Triassic-Jurassic transition.
On the completeness and Riesz basis property of root subspaces of boundary value problems for first order systems and applications
Authors: Lunyov Anton A. , Malamud Mark M.
Published: April 2015

The paper is concerned with the completeness property of root functions of general boundary value problems for

n \times n

first order systems of ordinary differential equations on a finite interval. In comparison with the recent paper [37] we substantially relax the assumptions on boundary conditions guaranteeing the completeness of root vectors, allowing them to be non-weakly regular and even degenerate. Emphasize that in this case the completeness property substantially depends on the values of a potential matrix at the endpoints of the interval.

It is also shown that the system of root vectors of the general

n \times n

Dirac type system subject to certain boundary conditions forms a Riesz basis with parentheses. Finally, we apply our results to the dynamic generator of spatially non-homogenous damped Timoshenko beam model.
Inertia of the matrix $[(p_i+p_j)^r]$
Authors: Bhatia Rajendra , Jain Tanvi
Published: April 2015

Let

p_1, p_2, …,p_n

be positive real numbers. It is well known that for all

r<0

the matrix

[(p_i+p_j)^r]

is positive definite. Our main theorem gives a count of the number of positive and negative eigenvalues of this matrix when

r > 0

: Connections with some other matrices that arise in Loewner’s theory of operator monotone functions and in the theory of spline interpolation are discussed.
On a rigidity result for the first conformal eigenvalue of the Laplacian
Authors: Petrides Romain
Published: April 2015

Given

(M,g)

a smooth compact Riemannian manifold without boundary of dimension

n\geq 3

, we consider the first conformal eigenvalue which is by definition the supremum of the first eigenvalue of the Laplacian among all metrics conformal to

g

of volume 1. We prove that it is always greater than

n\omega_n^{\frac{2}{n}}

, the value it takes in the conformal class of the round sphere, except if

(M,g)

is conformally diffeomorphic to the standard sphere.
Effects of mineral dust on global atmospheric nitrate concentrations
Authors: Karydis V. A. , Tsimpidi A. P. , Pozzer A. , Astitha M. , Lelieveld J.
Published: April 2015

Abstract. This study provides an assessment of the chemical composition and global aerosol load of the major inorganic aerosol components and determines the effect of mineral dust on their formation, focusing on aerosol nitrate. To account for this effect, the mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are added to the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers the interactions of K+-Ca2+-Mg2+-NH4+-Na+-SO42−-NO3−-Cl−-H2O aerosol components. Emissions of mineral dust aerosol components (K+-Ca2+-Mg2+-Na+) are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. The presence of the metallic ions on the simulated suite of components can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The updated model improved the nitrate predictions over remote areas and found that the fine aerosol nitrate concentration is highest over urban and industrialized areas (1–3 μg m−3), while coarse aerosol nitrate is highest close to deserts (1–4 μg m−3). The contribution of mineral dust components to nitrate formation is large in areas with high dust concentrations with impacts that can extend across southern Europe, western USA and northeastern China. The tropospheric burden of aerosol nitrate increases by 44% by considering the interactions of nitrate with mineral dust cations. The calculated global average nitrate aerosol concentration near the surface increases by 36% while the coarse and fine mode concentrations of nitrate increase by 53 and 21%, respectively. Sensitivity tests show that nitrate aerosol formation is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.
On the statistical optimality of CO2 atmospheric inversions assimilating CO2 column retrievals
Authors: Chevallier F.
Published: April 2015

Abstract. The extending archive of the Greenhouse Gases Observing SATellite (GOSAT) measurements (now covering about six years) allows increasingly robust statistics to be computed, that document the performance of the corresponding retrievals of the column-average dry air-mole fraction of CO2 (XCO2). Here, we compare a model simulation constrained by surface air-sample measurements with one of the GOSAT retrieval products (NASA's ACOS). The retrieval-minus-model differences result from various error sources, both in the retrievals and in the simulation: we discuss the plausibility of the origin of the major patterns. We find systematic retrieval errors over the dark surfaces of high-latitude lands and over African savannahs. More importantly, we also find a systematic over-fit of the GOSAT radiances by the retrievals over land for the high-gain detector mode, which is the usual observation mode. The over-fit is partially compensated by the retrieval bias-correction. These issues are likely common to other retrieval products and may explain some of the surprising and inconsistent CO2 atmospheric inversion results obtained with the existing GOSAT retrieval products. We suggest that reducing the observation weight in the retrieval schemes (for instance so that retrieval increments to the retrieval prior values are halved for the studied retrieval product) would significantly improve the retrieval quality and reduce the need for (or at least reduce the complexity of) ad-hoc retrieval bias correction. More generally, we demonstrate that atmospheric inversions cannot be rigorously optimal when assimilating XCO2 retrievals, even with averaging kernels.
Quantifying lower tropospheric methane concentrations using near-IR and thermal IR satellite measurements: comparison to the GEOS-Chem model
Authors: Worden J. R. , Turner A. J. , Bloom A. A. , Kulawik S. S. , Liu J. , Lee M. , Weidner R. , Bowman K. , Frankenberg C. , Parker R. , Payne V. H.
Published: April 2015

Abstract. Evaluating surface fluxes of CH4 using total column data requires models to accurately account for the transport and chemistry of methane in the free-troposphere and stratosphere, thus reducing sensitivity to the underlying fluxes. Vertical profiles of methane have increased sensitivity to surface fluxes because lower tropospheric methane is more sensitive to surface fluxes than a total column. Resolving the free troposphere from the lower-troposphere also helps to evaluate the impact of transport and chemistry uncertainties on estimated surface fluxes. Here we demonstrate the potential for estimating lower tropospheric CH4 concentrations through the combination of free-tropospheric methane measurements from the Aura Tropospheric Emission Spectrometer (TES) and XCH4 (dry-mole air fraction of methane) from the Greenhouse Gases Observing Satellite Thermal And Near Infrared for Carbon Observations (GOSAT TANSO, herein GOSAT for brevity). The mean precision of these estimates are calculated to be ~ 23 ppb for a monthly average on a 4 × 5 latitude/longitude degree grid making these data suitable for evaluating lower-tropospheric methane concentrations. Smoothing error is approximately 10 ppb or less. The accuracy is primarily determined by knowledge error of XCO2, used to estimate XCH4 from the GOSAT CH4/CO2 "proxy" retrieval. For example, we use different XCO2 fields to quantify XCH4 from the GOSAT CH4/CO2 retrieval, one from Carbontracker and another from the NASA Carbon Monitoring System, and find that differences of up to approximately 60 ppb are possible with a mean value of approximately 35 ppb or less for any given latitude for these lower-tropospheric methane estimates using these two different XCO2 distributions. We show that these lower-tropospheric concentrations are more directly sensitive to the underlying fluxes than a total column using the GEOS-Chem model. In particular, we compare these lower-tropospheric methane estimates with those from the GEOS-Chem model for July 2009 to determine if these data can capture methane enhancements associated with the high-latitude methane fluxes because both TES and GOSAT separately do not show much sensitivity to methane from these sources. We find that the spatial patterns and magnitude of lower tropospheric methane concentrations from GEOS-Chem over Northern European and Siberian wetland fluxes are consistent with these data but modeled concentrations are much larger than measured over Canadian wetland fluxes. Transport of methane significantly affects lower-tropospheric methane concentrations over S.E. Asia as both data and model show methane enhancements that are shifted away from their sources. A possible new finding is that there is no representation of a strong source between the Black and Caspian seas.
Quantifying the influence of CO2 seasonality on future ocean acidification
Authors: Sasse T. P. , McNeil B. I. , Matear R. J. , Lenton A.
Published: April 2015

Abstract. Ocean acidification is a predictable consequence of rising atmospheric carbon dioxide (CO2), and is highly likely to impact the entire marine ecosystem – from plankton at the base to fish at the top. Factors which are expected to be impacted include reproductive health, organism growth and species composition and distribution. Predicting when critical threshold values will be reached is crucial for projecting the future health of marine ecosystems and for marine resources planning and management. The impacts of ocean acidification will be first felt at the seasonal scale, however our understanding how seasonal variability will influence rates of future ocean acidification remains poorly constrained due to current model and data limitations. To address this issue, we first quantified the seasonal cycle of aragonite saturation state utilizing new data-based estimates of global ocean surface dissolved inorganic carbon and alkalinity. This seasonality was then combined with earth system model projections under different emissions scenarios (RCPs 2.6, 4.5 and 8.5) to provide new insights into future aragonite under-saturation onset. Under a high emissions scenario (RCP 8.5), our results suggest accounting for seasonality will bring forward the initial onset of month-long under-saturation by 17 years compared to annual-mean estimates, with differences extending up to 35 ± 17 years in the North Pacific due to strong regional seasonality. Our results also show large-scale under-saturation once atmospheric CO2 reaches 486 ppm in the North Pacific and 511 ppm in the Southern Ocean independent of emission scenario. Our results suggest that accounting for seasonality is critical to projecting the future impacts of ocean acidification on the marine environment.
Elemental quantification, chemistry, and source apportionment in golf course facilities in a semi-arid urban landscape using a portable X-ray fluorescence spectrometer
Authors: Udeigwe T. K. , Young J. , Kandakji T. , Weindorf D. C. , Mahmoud M. A. , Stietiya M. H.
Published: April 2015

Abstract. This study extends the application of the portable X-ray fluorescence (PXRF) spectrometry to the examination of elements in semi-arid urban landscapes of the Southern High Plains (SHP) of the United States, focusing on golf courses. The complex environmental challenges of this region and the unique management practices at golf course facilities could lead to differences in concentration and in the chemistry of elements between managed (irrigated) and non-managed (non-irrigated) portions of these facilities. Soil samples were collected at depths of 0–10, 10–20, and 20–30 cm from managed and non-managed areas of seven different facilities in the city of Lubbock, Texas, and analyzed for a suite of soil properties. Total elemental quantification was conducted using a PXRF spectrometer. Findings mostly indicated no significant differences in the concentration of examined elements between the managed and non-managed areas of the facilities. However, strong positive relationships (R = 0.82−0.91, p < 0.001) were observed among elements (e.g., Fe on the one hand and Cr, Mn, Ni, and As on the other; Cu and Zn; As and Cr) and between these elements and soil constituents or properties such as clay, calcium carbonate, organic matter, and pH. The strengths of these relationships were mostly higher in the non-managed areas, suggesting a possible alteration in the chemistry of these elements by anthropogenic influences in the managed areas. Principal component and correlation analyses within the managed areas suggested that As, Cr, Fe, Mn, and Ni could be of lithogenic origin, while Cu, Pb, and Zn could have anthropogenic influences. Only one possible, likely lithogenic, source of the elements was identified within the non-managed areas. As evidenced by the study, the PXRF spectrometer can be a valuable tool for elemental quantification and rapid investigation of elemental interaction and source apportionment in semi-arid climates.
Acute Subdural Hematoma after Isolated Traumatic Brain Injury: Risk Factors and Prediction of Mortality
Authors: Adukauskienė Dalia , Mačiulienė Asta , Čiginskienė Aušra , Adukauskaitė Agnė , Čyžiūtė Justina
Published: April 2015

The aim of this study was to determine mortality and it‘s risk factors also prediction of lethal outcome in case of acute subdural hematoma after isolated traumatic brain injury (ITBI). Methods. A retrospective study of 162 patients after ITBI was carried out in Neurosurgical Intensive Care Unit (NITS) of Lithuanian University of Health Sciences Hospital (LUHSH) Kaunas Clinics (KC). Demographic (gender, age), clinical (pupil reaction to light, Glasgow Coma Scale (GCS) score, APACHE II scale score) and laboratory (white blood cell count, glycemia) data analysis on the first day after the injury was made. Conclusions. The mortality rate of acute subdural hematoma after isolated traumatic brain injury was 41 pct. Risk factors of mortality were estimated to be patient age ≥ 65 yrs, absence of pupil reaction to light, GCS 3-8, APACHE II score ≥ 16 points, white blood cell count ≥10,1 x 109/l and glycemia ≥5,6mmol/l. It was estimated the evident relation between predicted lethal outcome and real mortality when the risk of lethal outcome was higher than 25 pct.
Primary Ovarian Abscess Arising Spontaneously within an Endometrioma: A Rare Case
Authors: Gupta Avantika , Gupta Madhavi Mathur , Manaktala Usha
Published: April 2015

We report a very rare case of de novo abscess formation inside an endometrioma without any prior intervention in a 32-year-old woman. She presented with acute abdominal pain and persistent high-grade fever. A lump was palpable and tender and showed features of endometrioma on ultrasound. Laparotomy was conducted, as her clinical condition deteriorated despite broad spectrum antibiotics, and her fever did not subside. Thick foul-smelling pus was drained from the endometrioma, and the abscess wall was removed, followed by cystectomy. The patient improved markedly and did well in the postoperative period.
Analogs of Luteinizing Hormone-Releasing Hormone in the Treatment of Endometriosis
Authors: Engel Jörg B. , Tinneberg Hans R. , Block Norman L. , Berkes Eniko , Schally Andrew V.
Published: April 2015

Agonists of luteinizing hormone-releasing hormone (LHRH) induce a reversible hypoestrogenic state through the down-regulation of LHRH receptors and desensitization of the pituitary. Since endometrial implants are estrogen sensitive, LHRH agonists have frequently been used for medical treatment of endometriosis. Nowadays, LHRH agonists can be considered in general as a second-line medical treatment for endometriosis-related symptoms, as oral therapy with dienogest is as effective and has fewer side effects. However, therapy with LHRH agonists for 3-6 months prior to in vitro fertilization remains the treatment of choice in patients with endometriosis, as it significantly increases pregnancy rates.

LHRH agonists are used prior to surgery and as an adjuvant after an operation to prevent recurrence or prolong disease-free intervals. Adverse effects of LHRH agonists are due to hypoestrogenism and include hot flushes, vaginal dryness, loss of libido, sleep disturbances and a diminished bone density which limits the duration of their administration to 6 months. For long-term treatment, add-back of estrogen and/or progestin,/or progestin only with or without bisphosphonates, can be used, but existing studies only cover a 12-month period of treatment.

LHRH antagonists competitively block the pituitary receptors for LHRH. Consequently, a partial pharmacological hypophysectomy with a reduction of the estrogen levels to a desired level is possible if LHRH antagonists are adequately dosed. As endometriotic implants require relatively high levels of estrogen, partially lower plasma levels of estrogens are sufficient to prevent the loss of bone density. A long-term treatment without add-back therapy is also possible.
Origen social y sobreeducación en los universitarios españoles: ¿es meritocrático el acceso a la clase de servicio?
Authors: Marqués Perales Ildefonso , Gil-Hernández Carlos J.
Published: April 2015

Este artículo analiza el impacto del origen social en la probabilidad de sobreeducación de una cohorte de universitarios españoles, nacida en los 70 y graduada en el curso 1999/2000, mediante la encuesta Refl ex-2005. Comprobamos la infl uencia de tres recursos asociados al origen social (capital cultural, social y económico) para poner a prueba uno de los pilares de la teoría de la modernización: la selección meritocrática. Hemos confi rmado que, aun controlando el campo de estudios, la experiencia laboral y la nota media, existe un efecto del capital cultural y social en la probabilidad de sobreeducación, no así del capital económico. Además, concluimos que el efecto directo del origen social en la sobreeducación no está mediado signifi cativamente por una elección del campo de estudios dependiente del origen social.
Why we should not skip aspirin in cardiovascular prevention
Authors: Schrör K.
Published: April 2015

Since more than 20 years, aspirin is an approved and established first-line antiplatelet medication in cardiovascular prevention. This is partially due to ist unique mode of action which is not shared with any other antiplatelet agent as well by the reliability of its pharmacological efficacy: inhibition of platelet COX-1 and subsequent thromboxane formation in almost every patient. Aspirin acts synergistic with ADP-antagonists in dual antiplatelet therapy of acute coronary syndroms (ACS) and percutaneous coronary interventions (PCI) and is also approved for long-term secondary prevention. Patients with atrial fibrillation are an exception and benefit more from anticoagulants. After the introduction of the new oral anticoagulants (NOACs), i.e. direct inhibitors of factor Xa or thrombin formation, there is a renewed discussion about the role of antiplatelet agents, specifically if additional dual antiplatelet treatment is still necessary for an optimum clinical effect or whether one component, such as aspirin might be skipped in favor of other classes of oral antiplatelet agents, such as ADP-antagonists. The available data are insufficient to recommend this because of a low number of studies and a still uncertain benefit/ risk (bleeding) ratio. More research on aspirin as a chemopreventive appears also to be necessary and is going on, in particular in individuals at high-risk for vascular thrombotic diseases (diabetics, preeclampsia, venous thrombembolism).
A Note on Smoking Behavior and Health Risk Taking
Authors: Pfeifer Christian
Published: April 2015

This research note presents two economic frameworks to describe the relationship between individual health risk aversion and smoking behavior. Using a large-scale representative data set (GSOEP), direct empirical evidence is found that individuals, who are more health risk taking, are more likely to be smokers and have a higher demand for cigarettes smoked per day. Non-linear specifications of risk taking reveal, however, that the risk effects are only significant for high risk takers. The estimated effects hold also separately for men and women.
Introducing waiting times for health care in a labor supply model for sickness absence
Authors: Andrén Daniela , Granlund David
Published: April 2015

This paper studies the association between waiting times for different health care services and the duration of sick leave, using a Swedish register database supplemented with information from questionnaires for 3,653 employees. The duration of sick leave is positively associated with waiting two weeks or more for primary care, technical investigations and specialists, compared to waiting one week or less. Except for waiting for a specialist, there is no indication that waiting four weeks or more is associated with longer durations of sick leave than waiting two to three weeks. Long waiting times for surgery is negatively associated with the duration of sick leave, which might be explained by prioritizing where patients with longer waiting times are those with less severe conditions. Including these waiting time variables did not induce substantial changes on the impact of traditional labor supply variables, which suggests that the parameter estimates of traditional variables are relatively robust. Published: Online August 2014. In print December 2015.
A Dual Neural Network as an Identifier for a Robot Arm
Authors: Rodríguez Sergio Alvarez , Hernández Carlos E. Castañeda
Published: April 2015

A novel dual recurrent neural network is presented and is used to identify the dynamics for a robot arm with three-Degrees of freedom (DoF) and trained with a filtered error algorithm. The dual neural network has a structure of two recurrent neural networks working simultaneously fighting each other to obtain the best identification values, being the criteria for the selection of the vest values: the standard deviation for the identification error. The neural identifier provides important information to a nonlinear block control transformation form acting as a control law to solve the trajectory tracking problem for the robotic plant's behavior.
VRM: A Unified Framework for Closed-Form Solutions of a Special Class of Serial Manipulators
Authors: Huo Xijian , Liu Yiwei , Jiang Li , Liu Hong
Published: April 2015

This paper proposes the virtual reconfiguration method (VRM) to construct the unified framework for closed-form solutions of a special class of serial manipulators. Central to the research is the inverse kinematics problem (KP) of 6- and 7-DOF serial manipulators, which contain either the Pieper's geometry or the Duffy's geometry. Given the desired end-effector pose of the manipulator, a virtual single chain (SLC) is developed by connecting the base and the end-effector with a hypothetical link. The equivalent single open chain (SOC) with different configurations can be obtained by cutting open the virtual SLC at one link between adjacent joints. Kinematic equivalence between the original manipulator and the new SOC is proven. Closed-form solutions of the original manipulator can be determined by solving the KP of the equivalent SOC. The VRM is further developed on the basis of the relationship between the manipulator and its equivalent SOC. In this paper, the KPs of 6-DOF manipulators with the spherical wrist and manipulators with the three-axis parallel shoulder joint are analysed. Principles and applications of the VRM are proposed. Finally, the validity and efficiency of the VRM are demonstrated by kinematics simulations of four different manipulators. Unlike traditional approaches, the VRM simplifies the computation of KPs and establishes a unified framework for closed-form solutions of the special class of 6- and 7-DOF serial manipulators, irrespective of the allocation of either the Pieper's geometry or the Duffy's geometry.
Recognition of Hand Gestures Observed by Depth Cameras
Authors: Kapuscinski Tomasz , Oszust Mariusz , Wysocki Marian , Warchol Dawid
Published: April 2015

We focus on gesture recognition based on 3D information in the form of a point cloud of the observed scene. A descriptor of the scene is built on the basis of a Viewpoint Feature Histogram (VFH). To increase the distinctiveness of the descriptor the scene is divided into smaller 3D cells and VFH is calculated for each of them. A verification of the method on publicly available Polish and American sign language datasets containing dynamic gestures as well as hand postures acquired by a time-of-flight (ToF) camera or Kinect is presented. Results of cross-validation test are given. Hand postures are recognized using a nearest neighbour classifier with city-block distance. For dynamic gestures two types of classifiers are applied: (i) the nearest neighbour technique with dynamic time warping and (ii) hidden Markov models. The results confirm the usefulness of our approach.
Adipose Stromal Cells Repair Pressure Ulcers in Both Young and Elderly Mice: Potential Role of Adipogenesis in Skin Repair
Authors: Strong Amy L. , Bowles Annie C. , MacCrimmon Connor P. , Frazier Trivia P. , Lee Stephen J. , Wu Xiying , Katz Adam J. , Gawronska-Kozak Barbara , Bunnell Bruce A. , Gimble Jeffrey M.
Published: April 2015

More than 2.5 million patients in the U.S. require treatment for pressure ulcers annually, and the elderly are at particularly high risk for pressure ulcer development. Current therapy for pressure ulcers consists of conservative medical management for shallow lesions and aggressive debridement and surgery for deeper lesions. The current study uses a murine model to address the hypothesis that adipose-derived stromal/stem cell (ASC) treatment would accelerate and enhance pressure ulcer repair. The dorsal skin of both young (2 months old [mo]) and old (20 mo) C57BL/6J female mice was sandwiched between external magnets for 12 hours over 2 consecutive days to initiate a pressure ulcer. One day following the induction, mice were injected with ASCs isolated from congenic mice transgenic for the green fluorescent protein under a ubiquitous promoter. Relative to phosphate-buffered saline-treated controls, ASC-treated mice displayed a cell concentration-dependent acceleration of wound closure, improved epidermal/dermal architecture, increased adipogenesis, and reduced inflammatory cell infiltration. The ASC-induced improvements occurred in both young and elderly recipients, although the expression profile of angiogenic, immunomodulatory, and reparative mRNAs differed as a function of age. The results are consistent with clinical reports that fat grafting improved skin architecture in thermal injuries; the authors of this published study have invoked ASC-based mechanisms to account for their clinical outcomes. Thus, the current proof-of-principle study sets the stage for clinical translation of autologous and/or allogeneic ASC treatment of pressure ulcers.

Significance

Adipose-derived stromal/stem cells (ASCs) promote the healing of pressure ulcer wounds in both young and old mice. ASCs enhance wound healing rates through adipogenic differentiation and regeneration of the underlying architecture of the skin.
Ciudadanía y Cuidados; apuntes para una política feminista democrática
Authors: Sales Gelabert Tomeu
Published: April 2015

El presente texto aborda la relación que hay entre la ciudadanía y los «cuidados» desde de una perspectiva feminista. En este sentido, la consideración, valorización e integración del cuidado como actividad, valor y relación política supone la necesaria rearticulación de la ciudadanía como identidad socio-política. Cualquier intento por elaborar crítica y propositivamente una ciudadanía inclusiva desde la perspectiva de género, ha de partir primero por la deconstrucción del discurso de la naturalización femenina del cuidado, y por otro lado, resituar y valorar el cuidado como actividad y valor que garantice el bienestar necesario para alcanzar una ciudadanía plena.
Prison et santé mentale. La jurisprudence de la Cour européenne des droits de l’homme
Authors: Tulkens1 Françoise , Dubois-Hamdi Claire
Published: April 2015

La présente contribution se propose, d’abord, de faire le point sur l’impact de la jurisprudence récente de la Cour relative à l’interdiction des traitements inhumains et dégradants – et incidemment au droit à la vie – sur la position juridique interne des personnes se trouvant en milieu carcéral et souffrant de problèmes de santé mentale (I et II). Il s’agira ensuite de discerner dans quelle mesure cette jurisprudence contribue à la réflexion sur le sens de la prison pour ce groupe de personnes doublement vulnérables (III). Il convient de préciser que nous visons ici les personnes qui ont commis un délit ou un crime et qui souffrent de troubles mentaux, sans faire de différence selon le profil des détenus ni le moment où sont apparus les troubles mentaux.
Troubles mentaux et tentatives de suicide chez les détenus. Le rôle du trouble du déficit de l’attention avec hyperactivité
Authors: Wright1 Christopher , Brouillard Marylène , Daigle Marc S. , Côté Gilles , Toupin Jean
Published: April 2015

En milieu carcéral, la prévalence des troubles mentaux et des décès par suicide atteint des proportions largement supérieures à celles de la population générale, le risque de mourir par suicide étant de 11 à 14 fois plus élevé. À partir d’un échantillon de 565 individus nouvellement incarcérés, le lien entre les tentatives de suicide et les troubles mentaux a été étudié, en mettant l’accent sur le trouble du déficit de l’attention avec hyperactivité (TDAH). Les résultats démontrent que la présence possible d’un TDAH chez un détenu augmente la probabilité d’avoir déjà fait une tentative de suicide, au même titre que la présence d’un trouble de l’Axe I ou II.
Statistical Review of the Annual Report on the Performance of Maritime Safety Inspection in Croatia
Authors: Stanivuk Tatjana , Medić Boris , Medić Marta
Published: April 2015

This paper provides a detailed analysis of the annual statistical report on the performance of Croatia’s Maritime Safety Inspection. Statistical data have been processed with regard to the number of employees at the Directorate for Inspection Affairs within the Ministry of Maritime Affairs, Transport and Infrastructure. A statistical analysis of the number of inspection surveys per area has been made, with tables and graphs providing a detailed account of the deficiencies detected on board vessels and the number of detentions in 2013. The results obtained provide an insight into the overall performance of the Maritime Safety Inspection in that year.
A switching periodic adaptive control approach for time‐varying parameters with unknown periodicity
Authors: Yu Miao , Huang Deqing
Published: April 2015

Periodic variations are encountered in many real systems, which can exist in the system parameters, as a disturbance or as the tracking objective. However, there exist a great number of situations where the periodicity is not known in advance. Hence, how to compensate for the effects of time‐varying parameters with unknown periodicity remains a challenge for the controller design. In this paper, we proposed a switching periodic adaptive control approach for continuous‐time nonlinear parametric systems with periodic uncertainties in which the period and bound are not known in advance. We utilized a fully saturated periodic adaptation law to identify the unknown periodic parameters in a pointwise manner. In addition, we provided a logic‐based switching scheme to estimate the unknown period and bound online simultaneously. By virtue of Lyapunov stability analysis, we show that the asymptotic convergence can be guaranteed irrespective of the initial conditions. Finally, we carried out numerical simulations to demonstrate the efficacy of the switching periodic adaptive control algorithm. The proposed approach can be applied to parametric nonlinear systems with time‐varying parameters of unknown periodicity irrespective of the types of periodic uncertainties. Copyright © 2015 John Wiley & Sons, Ltd.