bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on Damage Tolerance of Thick Laminate Composite Structure
Authors: Park Hyun Bum
Published: September 2015

This study is to investigate the compressive strength of the carbon/epoxy thick laminate after damage. Through damage tolerance of thick laminate is not standardized test because specimens exceed typical specimen thickness described in the ASTM standard, design allowable of thick laminate shall be determined by the experiment to address design criteria of the structure and incorporate functional capability with damage level. In this study, it is performed the research on damage tolerance of thick laminate adopting aircraft structure. The damage tolerance of thick laminates such as no damage and impact damage is evaluated under compression loading.
Strength Prediction of Laminated Composites upon Independent Constituent Properties
Authors: Huang Zheng Ming , Xin Li Min
Published: September 2015

To predict ultimate strength of a laminated composite subjected to any load only using its constituent fiber and matrix properties measured independently, three challenging problems must be resolved with high success. First, internal stresses in the fiber and matrix must be accurately determined. Second, efficient failure detection for laminae and laminate upon the internal stresses must be achieved. Last but not the least, input data for the in-situ strengths of the constituents must be defined correctly from their original counterparts, as the former, different from the latter, are immeasurable. This presentation briefly summarizes our work on the targeted subject. All of the three issues have been systematically addressed with reasonable success.
Simulation of the Transient Behavior of Matter with Characteristic Geometrical Variations & Defects Irradiated by Nanosecond Laser Pulses Using FEA
Authors: Kaselouris Evaggelos , Skarvelakis Emmanouil , Nikolos Ioannis K. , Stavroulakis Georgios E. , Orphanos Yannis , Bakarezos M. , Papadogiannis Nektarios A. , Tatarakis Michael , Dimitriou Vasilios
Published: September 2015

The thermomechanical transient response of matter illuminated by nanosecond laser pulses is modeled and simulated using the Finite Element Analysis (FEA). Matter’s behavior is numerically described by a three-dimensional (3D) multiphysics, coupled thermal structural, transient FEA, experimentally validated, model. FEA offers substantial insights into the materials’ micro-mechanical behaviour providing detailed information for the spatiotemporal evolution of acoustic waves. In this computational approach the impact of the geometric characteristics of the modeled metallic films to the generation and propagation of the ultrasonic waves, in relation to temperature, is investigated. The study is expanded to the dynamic reactions of matter in the presence of surface and solid volume defects and enclosures e.g.: gaps, holes or bubbles. The transient behavior of matter in the time and the space solution domains is obtained by the FEA model and presented.
A Simulation Study of Surface Breaking Crack in Concrete Beam Based on Time-Reversed Theory of Surface Wave
Authors: Yang Yang , Zhang Meng Yang , Xiao Li , Qu Wen Zhong
Published: September 2015

Existing non-destructive test methods are usually ineffective in detection of surface breaking cracks with large depths in concrete structure. This paper introduces a method suitable for detection of deep cracks based on surface wave time reversal theory. A numerical simulation based on the finite element model is performed to investigate surface cracks detection. A damage index was defined based on the correlation coefficient between the actuated and the reconstructed wave signals. The results demonstrated that the presence of crack had a significant influence on the propagation characteristics of surface waves along concrete. Cracks in different sizes were introduced and correlated with the damage index. Enlarging the crack depth resulted in an increase in the distortion of reconstructed signals, and a higher damage index was obtained. The results illustrated the effectiveness of the surface wave time-reversal process in identifying cracks in concrete structures.
Second-Order Computational Homogenization Approach Using Higher-Order Gradients at Microlevel
Authors: Lesičar Tomislav , Tonković Zdenko , Sorić Jurica
Published: September 2015

Realistic description of heterogeneous material behavior demands more accurate modeling at macroscopic and microscopic scales. To observe strain localization phenomena and material softening occurring at the microstructural level, an analysis on the microlevel is unavoidable. Multiscale techniques employing several homogenization schemes can be found in literature. Widely used second-order homogenization requires C1 continuity at the macrolevel, while standard C0 continuity has usually been hold at microlevel. However, due to the C1-C0 transition macroscale variables cannot be defined fully consistently. The present contribution is concerned with a multiscale second-order computational homogenization employing C1 continuity at both scales under assumptions of small strains and linear elastic material behavior. All algorithms derived are implemented into the FE software ABAQUS. The numerical efficiency and accuracy of the proposed computational strategy is demonstrated by modeling three point bending test of the notched specimen.
Study on the Durability of Cementless Concrete Produced with Industrial By-Products
Authors: Lee Jong Won , Jang Yong Il , Lee Byung Jae , Park Wan Shin
Published: September 2015

This study evaluated the durability of concrete produced with a cementless binding material and potassium hydroxide (KOH) based on ground granulated blast furnace slag and fly ash. These industrial byproducts are used to replace cement in order to reduce carbon dioxide emissions. The test conducted for the freezing and thawing resistance of concrete using cementless binding material revealed that the relative dynamic modulus was 83.4%. From the results of a chemical resistance test, the mass reduction rate stood at 12.3% for the 5% HCl solution and 12.7% for the 5% H2SO4 solution, showing better chemical resistance than concrete using cement. The depth of neutralization was observed to be 4.48mm, a similar level to that of cement-containing concrete.
The Influence of Wedge Shape on the Determination of Dynamic Fracture Toughness in SHPB Test
Authors: Zhu Shi Fan , Cao Yang , Guo Chun Huan , Jiang Feng Chun
Published: September 2015

The SHPB loading three-point bending specimen is a popular way for measuring the dynamic fracture toughness of the material. The wedge shapes on the loading end of the incident bar have necessary effects on the propagation of the stress wave. The dynamic mechanical response and the fracture toughness of the aluminum alloy were measured by SHPB with different wedge shapes, and the influences of wedge shape on determination of dynamic fracture toughness was analyzed in this study. The investigation result can be used to provide reference for the design of a new Hopkinson apparatus for dynamic fracture testing.
Mechanical Properties and Corrosion Mechanism of GFRP Rebar in Alkaline Solution
Authors: Mao Ji Ze , Zhang Hong Wei , Lv Jian Fu , Jia Dao Guang , Ao Shi Kai
Published: September 2015

Steel corrosion is one of the main problems of concrete structure durability. Compared with the steel, GFRP rebar has the advantages of high strength, low density and good corrosion resistance. Therefore, GFRP becomes a good choice to replace steel bar in concrete structure. Since GFRP material is susceptible to the alkaline conditions, it is necessary to clarify the mechanical properties and corrosion mechanism of GFRP rebar in such an alkaline environment of interior concrete. In this study, the artificial accelerated corrosion tests of two kinds of GFRP rebar (epoxy and unsaturated polyester resin matrix) were conducted at 60 °C in alkaline solution up to 90 days. Then the tensile strength tests of GFRP rebar were carried out. The solution PH values, the tensile strength and mass loss of GFRP rebar were measured. The testing results show that the mass of GFRP rebar had rarely changed, but the tensile strength reduced about 30% after 90-day immersion test in alkaline solution. During the test, the PH value of the alkaline solution decreased from 13.62 to around 12.85, which indicated that the hydroxyl ions of the alkaline solution had been consumed. The ester bonds in resin matrix may hydrolyze in alkaline solution and the bonding interface between fiber and resin can be damaged progressively. It can cause the performance degradation of GFRP rebar. In addition, the relationship between the loss of tensile strength and the reduction of PH can be determined. That means the durability of GFRP rebar in concrete can be enhanced by controlling or limiting the alkalinity when producing concrete. Finally, the GFRP rebar of epoxy resin matrix shows higher retention values of tensile strength and better alkali resistance than those of UPR matrix rebar after 90d immersion in the alkaline solution. The obtained results in this paper can provide application reference of GFRP materials in civil engineering.
Damage Model for Degradation Induced by Volcanic Ash Deposition on Thermal Barrier Coatings
Authors: Arai Masayuki , Hara Daigo
Published: September 2015

The importance of a land-based gas turbine has been increased in order to maintain energy security in Japan. Since our country has been always exposed to a natural disaster, it is necessary to consider about influence of air intake of volcanic ash spouted from a volcanic explosion on high-temperature components in gas turbine as well as vibration by an earthquake event. In this study, a high-temperature exposure tests were conducted for 8YZ/CoNiCrAlY/IN-738LC sample on which volcanic ash was deposited. Here, we selected the natural ash picked up from Shin-moe mountain where had been exploded in 2011. As a result, it was found that the top coating was peeled completely off at the exposure condition 1273 K for 100 hours, which means that volcanic ash deposition brings about some acceleration for the delamination life of TBC. The microstructure observation after the exposure tests revealed that Si and Ca contents involved in the volcanic ash was detected inside open-pores. Thus, it was identified that those ashes infiltrated into open pores along splat boundaries under a high-temperature exposure environment. The damage model for explaining degradation induced by volcanic ash deposition was developed based upon micromechanics. The formulae for constitutive equation of TBC was done by considering about influence of both crystal distortion by tetragonal to monoclinic phase transformation and thermal shrinking by temperature drop in the heat exposure treatment. Residual stress and interfacial energy were evaluated using the proposed constitutive equation in order to clarify degradation mechanisms for ash attack to TBC.
On the Role of Double Die Angle on the Hydrogen Embrittlement of Cold Drawn Prestressing Steel Wires
Authors: Toribio Jesús , Lorenzo Miguel , Vergara Diego
Published: September 2015

Residual stresses produced by cold drawing are an undesirable effect of the non-uniform plastic strain distribution generated during the conforming process used for obtaining prestressing steel wires. Among the diverse parameters of the process influencing the residual stress generation, one of the most relevant is the geometry of the drawing die and, in particular, the inlet die angle. Wires drawn with die angles as low as possible will exhibit a lower and more homogeneous plastic strain state and, therefore, a smaller and more uniform residual stress state. Thus, the hydrogen embrittlement (HE) susceptibility of such wires is also lower, thereby enlarging the life in service of these components. In this paper an innovative design of the drawing die is proposed using two consecutive angles (i.e., varying die angle) for reducing the residual stress-strain state in the cold drawn wires and, consequently, for improving the resistance to HE of prestressing steel wires.
Rheological Study of the Performance and the Vulnerability of an Element of RC Structure during and after a Seismic Signal
Authors: Belhadj A. F. , Chabaat Mohamed
Published: September 2015

If the dimensioning methods of new structures are well controlled, the forecast of the seismic levels for which an existing building resists is a problem much more difficult to define. Their behavior and their comportment are completely unknown. The modeling of deteriorating hysteretic behavior is becoming increasingly important. With numerical integration procedures and the spectacular progress of computers, it is possible to predict the nonlinear behavior of reinforced concrete structures by using material rheological models during and after an earthquake. The objective of this research work is to develop a rheological model which allows digital nonlinear simulations (material) of structural systems excited by cyclic loads taken from seismic sources such as they are presented in reality, meaning in the form of digitalized accelerogram. This procedure requires a calibration dictated by particular transformations for the case of RC structures under this type of excitation in all points of the system and at every moment during the lasting of the signal. Besides, macrofibers models offer a satisfactory approach for analyzing all RC structures by taking into account various generated phenomena.
Finite Element Analysis on Crack Tip Deformation Behavior under Mode-II Loading in Single Crystal Superalloy
Authors: Mukai Yasuhiro , Kagawa Hiroyuki , Okazaki Masakazu
Published: September 2015

Crack tip deformation behavior of single crystal superalloy under mode-II shear stress condition was evaluated by crystal plasticity finite element method by applying Eshelby’s inclusion theory to express the relation between microscopic and macroscopic stress/strain character, and the influence of γ/γ’ microstructure and anomalous temperature dependence of yield strength in γ’ phase on crack tip deformation behavior was studied
Evaluation of Bond Strength between Steel Fiber Reinforced Ultra-High Strength Concrete and Rebar
Authors: Bae B.I. , Choi Hyun Ki , Choi Chang Sik
Published: September 2015

In order to design reinforced concrete member using steel fiber ultra high strength concrete, current structural design methods should be re-evaluated because it has significant difference in material characteristics compared with normal concrete. In this study, bond strength of steel fiber reinforced ultra-high strength concrete was evaluated. For this purpose, direct pull out test specimens were constructed with variables of cover thickness, compressive strength of matrix and fiber inclusion ratio. According to the test, bond strength were sensitively varied with cover thickness and fiber inclusion. Because bond strength was determined by tensile strength of concrete. Comparing test results with theoretical methods suggested by Tepfers, specimens without steel fiber show good agreement with analytical method, because this method were based on elasticity. And other empirical equations were evaluated with other previous researches.
Effects of Fine Particle Peening on Fatigue Strength of Transformation-Induced Plasticity (TRIP)-Aided Martensitic Steel
Authors: Sugimoto Koh Ichi , Mizuno Yuta , Hojo Tomohiko
Published: September 2015

The effects of fine particle peening on the torsional strength of a transformation-inducedplasticity (TRIP)-aided martensitic (TM) steel were investigated for applications to precision gears. Fine particle peening increased the fatigue limits and lowered the notch-sensitivities of steel, compared with quenched and subsequently tempered SNCM420 steel. In addition, fine particle peening lowered the fatigue crack propagation rate in TM steel with a high threshold value of the stress intensity range. These results were associated with (1) higher Vickers hardness, (2) higher compressive residual stress, and (3) a larger amount of untransformed retained austenite in the surface layer when compared with SNCM420 steel.
Fatigue Crack Growth Behaviour of Friction Stir Welded Aluminium Alloys
Authors: Labeas G. , Peppa S.
Published: September 2015

The effect of Friction Stir Welding joining process on the damage tolerance behaviour of friction stir welded aluminium alloys is experimentally investigated. Fatigue crack propagation tests for different aluminium alloys and welding configurations have been performed. The main conclusion arising from the experimental study is that the damage tolerance behaviour of the welded material is in most cases comparable to the base material. Furthermore, the most critical area of the joint was identified to be the weld interface, i.e. the area between the nugget and the thermo-mechanically affected zone
Red cell allo- and autoimmunisation in transfused sickle cell and cancer patients in Kenyatta National Hospital, Nairobi, Kenya
Authors: Mangare Caroline , Mbugua Amos , Maturi Peter , Rajab Jamila , Blasczyk Rainer , Heuft Hans-Gert
Published: September 2015

Background: Currently, no data are available on the prevalence of red blood cell (RBC) antibody formation amongst Kenyan patients with multiple transfusion needs, such as patients with sickle cell disease (SCD) or haematological malignancies (HM) and solid (SM) malignancies.Objectives: We determined the prevalence and specificities of RBC alloantibodies and autoantibodies in two patient groups with recurrent transfusion demands at Kenyatta National Hospital, Nairobi, Kenya.Method: Between February and August 2014, 300 samples from SCD, HM and SM patients were collected and screened for alloantibodies. Samples from 51 healthy blood donors were screened for irregular antibodies and phenotyped.Results: Amongst the 228 patients with viable samples (SCD, n = 137; HM, n = 48; SM, n = 43), the median transfusion frequency was two to three events per group, 38 (16.7%) were RBC immunised and 32 (14.0%) had a positive direct antiglobulin test. We identified specific alloantibodies in six patients (2.6%). Four of these six were SCD patients (2.9%) who had specific RBC alloantibodies (anti-Cw, anti-M, anti-Cob, anti-S); amongst HM patients one had anti-K and one had anti-Lea. RBC autoantibody prevalence was 3.1% (7/228). Amongst the healthy blood donors, the Ror, ccD.ee and R2r, ccD.Ee phenotypes accounted for 82% of the Rhesus phenotypes and all were Kell negative.Conclusion: The numbers of transfusions and the rates of RBC alloantibodies are low and the most important RBC alloantibody-inducing blood group antigens are relatively homogeneously distributed in this population. A general change in the Kenyatta National Hospital pre-transfusion test regimen is thus not necessary. The current transfusion practice should be reconsidered if transfusion frequencies increase in the future.
Improving the quality of nurse clinical documentation for chronic patients at primary care clinics: A multifaceted intervention
Authors: Mahomed Ozayr H. , Naidoo Salsohni , Asmall Shaidah , Taylor Myra
Published: September 2015

Background: Deficiencies in record keeping practices have been reported at primary care level in the public health sector in South Africa. These deficiencies have the potential to negatively impact patient health outcomes as the break in information may hinder continuity of care. This disruption in information management has particular relevance for patients with chronic diseases.Objectives: The aim of this study was to establish if the implementation of a structured clinical record (SCR) as an adjunct tool to the algorithmic guidelines for chronic disease management improved the quality of clinical records at primary care level.Method: A quasi-experimental study (before and after study with a comparison group) was conducted across 30 primary health care clinics (PHCs) located in three districts in South Africa. Twenty PHCs that received the intervention were selected as intervention clinics and 10 facilities were selected as comparison facilities. The lot quality assurance sampling (LQAS) method was used to determine the number of records required to be reviewed per diagnostic condition per facility.Results: There was a a statistically significant increase in the percentage of clinical records achieving compliance to the minimum criteria from the baseline to six months post-intervention for both HIV patients on antiretroviral treatment and patients with non-communicable diseases (hypertension and diabetes).Conclusions: A multifaceted intervention using a SCR to supplement the educational outreach component (PC 101 training) has demonstrated the potential for improving the quality of clinical records for patients with chronic diseases at primary care clinics in South Africa.
‘Der Tag des Herrn ist schon da’ (2 Thess 2:2b) – Ein Schlüsselproblem zum Verständnis des 2. Thessalonicherbriefs
Authors: Nicklas Tobias , Sommer Michael
Published: September 2015

‘The day of the Lord is already here’ (2 Thess 2:2b) – A key problem to the understanding of the second letter to the Thessalonians. 2 Thessalonians 2:2b, that is, the words ἐνέστηκεν ἡ ἡμέρα τοῦ κυρίου are a crux interpretum. At the same time their interpretation is crucial for the overall understanding of 2 Thessalonians. Does this text offer a view of early Christian eschatology totally different from Paul’s or is it compatible to what we read for example in 1 Thessalonians? The article deals critically with two recent monographs by Norbert Baumert and Maria-Irma Seewann who offered a new interpretation of the passage according to which 2 Thessalonians 2:2 is not concerned with matters of Parousia, but with Christ’s presence in the community. It offers an overview of the development of the ‘Day of the Lord’ traditions in the Old Testament and Early Judaism and shows that Baumert and Seewann’s interpretation is untenable. After an analysis of the context of 2 Thessalonians 2:1–2 the article develops an own interpretation of 2 Thessalonians’ 2:2 in light of a parallel in Hippolyt’s Commentary on Daniel. The eschatology of 2 Thessalonians 2 finally, provides an argument for the text’s pseudepigraphy.
Glass injuries seen in the emergency department of a South African district hospital
Authors: Nzaumvila Doudou , Govender Indiran , Kramer Efraim B.
Published: September 2015

Background: The emergency department of Embhuleni Hospital frequently manages patients with glass-related injuries. This study assessed these injuries and the glass that caused them in more detail.Aim: The objectives of our study included determining the type of glass causing these injuries and describing the circumstances associated with different types of glass injuries.Setting: The emergency department of Embhuleni Hospital in Elukwatini, Mpumalanga province, South Africa.Methods: This was a cross-sectional study with a sample size of 104 patients. Descriptive statistics were used to assess the characteristics of the glass injuries.Results: Five different types of glass were reported to have caused the injuries, namely car glass (7.69%), glass ampoules (3.85%), glass bottles (82.69%), glass windows (3.85%) and street glass shards (1.92%). Glass bottle injuries were mainly caused by assaults (90.47%) and most victims were mostly young males (80.23%). The assaults occurred at alcohol-licensed premises in 65.11% of cases. These injuries occurred mostly over weekends (83.72%), between 18:00 and 04:00. The face (34.23%) and the scalp (26.84%) were the sites that were injured most often.Conclusion: Assault is the most common cause of glass injuries, usually involving young men at alcohol-licensed premises. Glass injuries generally resulted in minor lacerations, with few complications (2.68%).
Reputação Corporativa e a Criação de Riqueza nas Empresas Listadas na BM&FBovespa
Authors: De Luca Márcia Martins Mendes , Góis Alan Diógenes , Costa Juliana Almeida , Maia Ana Jeniffer Rebouças
Published: September 2015

Este estudo tem como objetivo investigar a relação entre a reputação corporativa e a criação de riqueza pelas companhias listadas na BM&FBovespa, considerando a Teoria da Sinalização. Fez-se uso da Regressão Linear Múltipla e do teste de Mann-Whitney, em uma amostra de 309 empresas. A coleta de dados foi realizada com base nas Demonstrações Financeiras Padronizadas, no Formulário de Referência e na participação das empresas em alguns rankings. Os resultados revelaram que (i) a criação de riqueza é influenciada pela reputação corporativa, assim como o tamanho, o endividamento, a proporção de ativos intangíveis, a idade e a internacionalização; (ii) há diferenças estatisticamente significantes entre as empresas com reputação e aquelas que não possuem reputação corporativa. Conclui-se que manter uma boa reputação corporativa, sendo esta considerada um ativo intangível, dificilmente copiada e proveniente dos sinais positivos emitidos para os stakeholders, constitui fator determinante na explicação da criação de riqueza.
The impact of observing characteristics on the ability to predict ozone under varying polluted photochemical regimes
Authors: Hamer P. D. , Bowman K. W. , Henze D. K. , Attié J.-L. , Marécal V.
Published: September 2015

Abstract. We conduct analyses to assess how characteristics of observations of ozone and its precursors affect air quality forecasting and research. To carry out this investigation, we use a photochemical box model and its adjoint integrated with a Lagrangian 4D-variational data assimilation system. Using this framework in conjunction with pseudo-observations, we perform an ozone precursor source inversion and estimate surface emissions. We then assess the resulting improvement in ozone air quality prediction. We use an analytical model to conduct uncertainty analyses. Using this analytical tool, we address some key questions regarding how the characteristics of observations affect ozone precursor emission inversion and in turn ozone prediction. These questions include what the effect is of choosing which species to observe, of varying amounts of observation noise, of changing the observing frequency and the observation time during the diurnal cycle, and of how these different scenarios interact with different photochemical regimes. In our investigation we use three observed species scenarios: CO and NO2; ozone, CO, and NO2; and HCHO, CO and NO2. The photochemical model was set up to simulate a range of summertime polluted environments spanning NOx-(NO and NO2)-limited to volatile organic compound (VOC)-limited conditions. We find that as the photochemical regime changes, here is a variation in the relative importance of trace gas observations to be able to constrain emission estimates and to improve the subsequent ozone forecasts. For example, adding ozone observations to an NO2 and CO observing system is found to decrease ozone prediction error under NOx- and VOC-limited regimes, and complementing the NO2 and CO system with HCHO observations would improve ozone prediction in the transitional regime and under VOC-limited conditions. We found that scenarios observing ozone and HCHO with a relative observing noise of lower than 33 % were able to achieve ozone prediction errors of lower than 5 ppbv (parts per billion by volume). Further, only observing intervals of 3 h or shorter were able to consistently achieve ozone prediction errors of 5 ppbv or lower across all photochemical regimes. Making observations closer to the prediction period and either in the morning or afternoon rush hour periods made greater improvements for ozone prediction: 0.2–0.3 ppbv for the morning rush hour and from 0.3 to 0.8 ppbv for the afternoon compared to only 0–0.1 ppbv for other times of the day. Finally, we made two complementary analyses that show that our conclusions are insensitive to the assumed diurnal emission cycle and to the choice of which VOC species emission to estimate using our framework. These questions will address how different types of observing platform, e.g. geostationary satellites or ground monitoring networks, could support future air quality research and forecasting.
What controls the vertical distribution of aerosol? Relationships between process sensitivity in HadGEM3–UKCA and inter-model variation from AeroCom Phase II
Authors: Kipling Z. , Stier P. , Johnson C. E. , Mann G. W. , Bellouin N. , Bauer S. E. , Bergman T. , Chin M. , Diehl T. , Ghan S. J. , Iversen T. , Kirkevåg A. , Kokkola H. , Liu X. , Luo G. , van Noije T. , Pringle K. J. , von Salzen K. , Schulz M. , Seland Ø. , Skeie R. B. , Takemura T. , Tsigaridis K. , Zhang K.
Published: September 2015

Abstract. The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors, we investigate the effects of individual processes in one particular model (HadGEM3–UKCA), and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment. In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficiently coarse variations in these processes can produce a similar diversity to that among different models in terms of the global mean profile and zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models. Convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulphate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea-salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only. In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number, while the profiles of larger particles are controlled by the same processes as the component mass profiles, plus the size distribution of primary emissions. We also show that the processes that affect the AOD-normalised radiative forcing in the model are predominantly those that affect the vertical mass distribution, in particular convective transport, in-cloud scavenging, aqueous oxidation, ageing and the vertical extent of biomass-burning emissions.
Transport pathways from the Asian monsoon anticyclone to the stratosphere
Authors: Garny H. , Randel W. J.
Published: September 2015

Abstract. Transport pathways of air originating in the upper tropospheric Asian monsoon anticyclone are investigated based on three-dimensional trajectories. The Asian monsoon anticyclone emerges in response to persistent deep convection over India and southeast Asia in northern summer, and this convection is associated with rapid transport from the surface to the upper troposphere, and possibly into the stratosphere. Here, we investigate the fate of air that originates within the upper tropospheric anticyclone from the outflow of deep convection, using trajectories driven by ERA-interim reanalysis data. Calculations include isentropic estimates, plus fully three-dimensional results based on kinematic and diabatic transport calculations. Isentropic calculations show that air parcels are typically confined within the anticyclone for 10–20 days, and spread over the tropical belt within a month of their initialization. However, only few parcels (3 % at 360 K, 8 % at 380 K) reach the extratropical stratosphere by isentropic mixing. When considering vertical transport we find that 31 % (48%) of the trajectories reach the stratosphere within 60 days when using vertical velocities or diabatic heating rates to calculate vertical transport, respectively. In both cases, most parcels that reach the stratosphere are transported upward within the anticyclone and enter the stratosphere in the tropics, typically 10–20 days after their initialization at 360 K. This suggests that trace gases, including pollutants, that are transported into the stratosphere via the Asian monsoon system are in a position to enter the tropical pipe and thus be transported into the deep stratosphere. Sensitivity calculations with respect to the initial altitude of the trajectories showed that air needs to be transported to levels of 360 K or above by deep convection to likely (≧50 %) reach the stratosphere through transport by the large-scale circulation.
Observations of fluorescent aerosol–cloud interactions in the free troposphere at the Sphinx high Alpine research station, Jungfraujoch
Authors: Crawford I. , Lloyd G. , Bower K. N. , Connolly P. J. , Flynn M. J. , Kaye P. H. , Choularton T. W. , Gallagher M. W.
Published: September 2015

Abstract. The fluorescent nature of aerosol at a high Alpine site was studied using a wide-band integrated bioaerosol (WIBS-4) single particle multi-channel ultra violet-light induced fluorescence (UV-LIF) spectrometer. This was supported by comprehensive cloud microphysics and meteorological measurements with the aims of cataloguing concentrations of bio-fluorescent aerosols at this high altitude site and also investigating possible influences of UV-fluorescent particle types on cloud–aerosol processes. Analysis of background free tropospheric air masses, using a total aerosol inlet, showed there to be a minor but statistically insignificant increase in the fluorescent aerosol fraction during in-cloud cases compared to out of cloud cases. The size dependence of the fluorescent aerosol fraction showed the larger aerosol to be more likely to be fluorescent with 80 % of 10 μm particles being fluorescent. Whilst the fluorescent particles were in the minority (NFl/NAll = 0.27±0.19), a new hierarchical agglomerative cluster analysis approach, Crawford et al. (2015) revealed the majority of the fluorescent aerosol were likely to be representative of fluorescent mineral dust. A minor episodic contribution from a cluster likely to be representative of primary biological aerosol particles (PBAP) was also observed with a wintertime baseline concentration of 0.1±0.4 L−1. Given the low concentration of this cluster and the typically low ice active fraction of studied PBAP (e.g. pseudomonas syringae) we suggest that the contribution to the observed ice crystal concentration at this location is not significant during the wintertime.
Inter-annual and seasonal trends of vegetation condition in the Upper Blue Nile (Abay) Basin: dual-scale time series analysis
Authors: Teferi E. , Uhlenbrook S. , Bewket W.
Published: September 2015

Abstract. A long-term decline in ecosystem functioning and productivity, often called land degradation, is a serious environmental challenge to Ethiopia that needs to be understood so as to develop sustainable land use strategies. This study examines inter-annual and seasonal trends of vegetation cover in the Upper Blue Nile (UBN) or Abbay Basin. The Advanced Very High Resolution Radiometer (AVHRR)-based Global Inventory, Monitoring, and Modeling Studies (GIMMS) normalized difference vegetation index (NDVI) was used for long-term vegetation trend analysis at low spatial resolution. Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI data (MOD13Q1) were used for medium-scale vegetation trend analysis. Harmonic analyses and non-parametric trend tests were applied to both GIMMS NDVI (1981–2006) and MODIS NDVI (2001–2011) data sets. Based on a robust trend estimator (Theil–Sen slope), most parts of the UBN (~ 77 %) showed a positive trend in monthly GIMMS NDVI, with a mean rate of 0.0015 NDVI units (3.77 % yr−1), out of which 41.15 % of the basin depicted significant increases (p < 0.05), with a mean rate of 0.0023 NDVI units (5.59 % yr−1) during the period. However, the MODIS-based vegetation trend analysis revealed that about 36 % of the UBN showed a significant decreasing trend (p < 0.05) over the period 2001–2011 at an average rate of 0.0768 NDVI yr−1. This indicates that the greening trend of the vegetation condition was followed by decreasing trend since the mid-2000s in the basin, which requires the attention of land users and decision makers. Seasonal trend analysis was found to be very useful to identify changes in vegetation condition that could be masked if only inter-annual vegetation trend analysis was performed. Over half (60 %) of the Abay Basin was found to exhibit significant trends in seasonality over the 25-year period (1982–2006). About 17 and 16 % of the significant trends consisted of areas experiencing a uniform increase in NDVI throughout the year and extended growing season, respectively. These areas were found primarily in shrubland and woodland regions. The study demonstrated that integrated analysis of inter-annual and intra-annual trends based on GIMMS and MODIS enables a more robust identification of changes in vegetation condition.
Scaling regimes and linear and nonlinear responses of last millennium climate models to volcanic and solar forcings
Authors: Lovejoy S. , Varotsos C. A.
Published: September 2015

Abstract. At scales much longer than the deterministic predictability limits (about 10 days), the statistics of the atmosphere undergo a drastic transition, the high frequency weather acts as a random forcing on the lower frequency macroweather. In addition, up to decadal and centennial scales the equivalent radiative forcings of solar, volcanic and anthropogenic perturbations are small compared to the mean incoming solar flux. This justifies the common practice of reducing forcings to radiative equivalents (which are assumed to combine linearly), as well as the development of linear stochastic models, including for forecasting at monthly to decadal scales. In order to clarify the validity of the linearity assumption and determine its range of validity, we use last Millennium simulations, both with the simplified Zebiac–Cane (ZC) model and the NASA GISS E2-R fully coupled GCM. We systematically compare the statistical properties of solar only, volcanic only and combined solar and volcanic forcings over the range of time scales from one to 1000 years. We also compare the statistics to multiproxy temperature reconstructions. The main findings are: (a) that the variability of the ZC and GCM models are too weak at centennial and longer scales, (b) for longer than ≈ 50 years, the solar and volcanic forcings combine subadditively (nonlinearly) compounding the weakness of the response, (c) the models display another nonlinear effect at shorter scales: their sensitivities are much higher for weak forcing than for strong forcing (their intermittencies are different) and we quantify this with statistical scaling exponents.
r.randomwalk v1.0, a multi-functional conceptual tool for mass movement routing
Authors: Mergili M. , Krenn J. , Chu H.-J.
Published: September 2015

Abstract. We introduce r.randomwalk, a flexible and multi-functional open source tool for backward- and forward-analyses of mass movement propagation. r.randomwalk builds on GRASS GIS, the R software for statistical computing and the programming languages Python and C. Using constrained random walks, mass points are routed from defined release pixels of one to many mass movements through a digital elevation model until a defined break criterion is reached. Compared to existing tools, the major innovative features of r.randomwalk are: (i) multiple break criteria can be combined to compute an impact indicator score, (ii) the uncertainties of break criteria can be included by performing multiple parallel computations with randomized parameter settings, resulting in an impact indicator index in the range 0–1, (iii) built-in functions for validation and visualization of the results are provided, (iv) observed landslides can be back-analyzed to derive the density distribution of the observed angles of reach. This distribution can be employed to compute impact probabilities for each pixel. Further, impact indicator scores and probabilities can be combined with release indicator scores or probabilities, and with exposure indicator scores. We demonstrate the key functionalities of r.randomwalk (i) for a single event, the Acheron Rock Avalanche in New Zealand, (ii) for landslides in a 61.5 km2 study area in the Kao Ping Watershed, Taiwan; and (iii) for lake outburst floods in a 2106 km2 area in the Gunt Valley, Tajikistan.
Atmospheric circulation patterns, cloud-to-ground lightning, and locally intense convective rainfall associated with debris flow initiation in the Dolomite Alps of northeastern Italy
Authors: Underwood S. J. , Schultz M. D. , Berti M. , Gregoretti C. , Simoni A. , Mote T. L. , Saylor A. M.
Published: September 2015

Abstract. The Dolomite Alps of northeastern Italy experience debris flows with great frequency during the summer months. An ample supply of unconsolidated material on steep slopes and a summer season climate regime characterized by recurrent thunderstorms combine to produce an abundance of these destructive hydrogeologic events. In the past debris flow events have been studied primarily in the context of their geologic and geomorphic characteristics. The atmospheric contribution to these mass wasting events has been limited to recording rainfall and developing intensity thresholds for debris mobilization. This study aims to expand the examination of atmospheric processes that preceded both locally intense convective rainfall (LICR) and debris flows in the Dolomite region. 500 hPa pressure level plots of geopotential heights were constructed for a period of three days prior to debris flow events to gain insight into the synoptic scale processes which provide an environment conducive to LICR in the Dolomites. Cloud-to-ground (CG) lightning flash data recorded at the meso-scale were incorporated to assess the convective environment proximal to debris flow source regions. Twelve events were analyzed and from this analysis three common synoptic scale circulation patterns were identified. Evaluation of CG flashes at smaller spatial and temporal scales illustrated that convective processes vary in their production of CG flashes (total number) and the spatial distribution of flashes can also be quite different between events over longer periods. During the 60 min interval immediately preceding debris flow a majority of cases exhibited spatial and temporal collocation of LICR and CG flashes. Also a number of CG flash parameters were found to be significantly correlated to rainfall intensity prior to debris flow initiation.
The dynamic connection of the Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current
Authors: Lambert E. , Le Bars D. , de Ruijter W. P. M.
Published: September 2015

Abstract. East of Madagascar, wind and surface buoyancy fluxes reinforce each other, leading to frontogenesis, outcrop and an eastward along-front flow: the South Indian Ocean Countercurrent (SICC). In the east the Leeuwin Current (LC) is a unique eastern boundary current which flows poleward along Australia. It is often described as a regional coastal current forced by an off-shore meridional density gradient or a sea surface slope, yet little is known of the forcing and dynamics that control these open ocean meridional gadients. To complete this understanding, we make use of both an ocean general circulation model and a conceptual two-layer model. The SICC impinges on west Australia and adds to a sea level slope and a southward geostrophic coastal jet: the Leeuwin Current. The SICC and the LC are thus dynamically connected. An observed transport maximum of the LC around 22° S is directly related to this impingement of the SICC. The circulation of the Indonesian Throughflow (ITF) through the Indian Ocean appears to be partly trapped in the upper layer north of the outcrop line and is redirected along this outcrop line to join the eastward flow of the SICC. Shutdown of the ITF in both models strongly decreases the Leeuwin Current transport and breaks the connection between the LC and SICC. In this case, most of the SICC was found to reconnect to the internal gyre circulation in the Indian Ocean. The Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current are thus dynamically coupled.
COMPARISON OF THREE DIFFERENT DEGRADATION METHODS TO PRODUCE LIQUID EPOXIDIZED NATURAL RUBBER
Authors: Rooshenass Pejvak , Yahya Rosiyah , Gan Seng Neon
Published: September 2015

Epoxidized natural rubber (ENR) has a high molecular weight, which has limited its solubility and processibility. For many potential applications, such as adhesives and coatings, ENR needs to be degraded into shorter chain lengths to form liquid ENR (LENR). We compared three different methods of preparing LENR: mechanical milling, chemical degradation initiated by potassium peroxodisulfate, and photooxidation initiated by ultraviolet (UV) irradiation. All the methods break down the ENR via free radicals but at different rates and by different mechanisms. In the LENR produced by these methods, ketone, aldehyde, carboxylic acid, and ester and lactone groups were observed; however, a hydrofuranic structure was only formed with UV degradation. The oxirane group was not affected significantly during the degradation, indicating that the chain sessions occurred predominantly via the –C=C– bonds. Spectroscopic analyses revealed that the consumption of a double bond is related to the extent of degradation initiated by potassium peroxodisulfate and UV irradiation. Mastication with a two roll mill produced LENR with a greater degree of unsaturation and fewer polar groups; therefore, presumably, significant chain scissions occurred from the rupturing of –C–C– single bonds. Comparing the reaction time, more LENR was obtained by UV degradation. As expected, an increase in the oxygen concentration led to the generation of more radicals, which could result in some coupling reactions.
Gly972Arg Variant of Insulin Receptor Substrate 1 Gene and Colorectal Cancer Risk in Overweight/Obese Subjects
Authors: Mahmoudi Touraj , Majidzadeh-A Keivan , Karimi Khatoon , Farahani Hamid , Dabiri Reza , Nobakht Hossein , Asadi Asadollah , Karimi Negar , Arkani Maral , Zali Mohammad Reza
Published: September 2015

Background

Given the major role of obesity and insulin resistance (IR) in colorectal cancer (CRC), we investigated whether genetic variants in ghrelin ( GHRL), resistin ( RETN) and insulin receptor substrate 1 ( IRS1) were associated with CRC risk.

Methods

This study was conducted as a case-control study, and 750 subjects, including 438 controls and 312 patients with CRC, were enrolled and genotyped using the PCR-RFLP method.

Results

No significant differences were observed for GHRL (rs696217), RETN (rs3745367) and IRS1 (rs1801278, Gly972Arg or G972R) gene variants between the cases and controls. However, the IRS1 G972R R allele compared with the G allele and the G972R RR+GR genotype compared with the GG genotype appeared to be markers of decreased CRC susceptibility in the overweight/obese subjects (p = 0.024; odds ratio [OR] = 0.42, 95% confidence interval [95% CI], 0.20-0.91; and p = 0.048; OR = 0.42, 95% CI, 0.17-0.99, respectively). Furthermore, the R allele and RR+GR genotype were also associated with decreased risks for obesity in the patients with CRC (p = 0.007; OR = 0.35, 95% CI, 0.15-0.77; and p = 0.015; OR = 0.35, 95% CI, 0.15-0.72, respectively).

Conclusions

In accordance with previous studies, our findings suggest that the IRS1 G972R R allele and RR+GR genotype have protective effects for CRC in overweight/obese patients and for obesity in patients with CRC. Nevertheless, further studies are required to confirm these findings.