bluuebunny/crossref_metadata_2025 huggingface dataset:
Ductile Failure Modelling in AA5182 Aluminium Alloy Sheet Forming
Authors: Aretz Holger , Keller Stefan , Engler Olaf , Brinkman Henk Jan
Published: June 2013

A modular ductile failure model is presented and applied to the forming of an AA5182 aluminium alloy sheet. A detailed description of the failure model and its calibration is provided. The final application of the calibrated failure model to the deep drawing of a cruciform cup reveals a good correlation with the experimental findings. Finally, a study on the influence of the r-value on formability is conducted.
Analysis of the Stress Components during the Forming of a Textile Composite Reinforcement
Authors: Hivet Gilles , Vidal-Sallé Emmanuelle , Boisse Philippe
Published: June 2013

When a continuum approach is considered for textile reinforcements, the internal loads are described by a stress tensor. The mechanical behaviour of the textile material is very much dependent on the fiber directions, and the frames defined from warp and weft directions are preferred to write the stress components. The exterior loads in these frames permit to define tensile and pure shear states. Nevertheless these frames are generally not orthogonal. The relationships between the exterior loads and the different stress components are analyzed in the present paper, and, in particular, the relationship between direct stress components and longitudinal loads on one hand, and shear stress components and transversal loads on the other hand. When dealing with textile materials, the exterior loads in the direction of the fibres and transverse to the fibres define the pure tensile and pure shear state. It will be shown that the covariant stress component matrix is diagonal in a pure tensile loading and that the first mixed direct stress components are equal to zero in a pure shear loading. In these cases, the direct relationship between the stresses and the loadings are given. This will be applied to the cases of the picture frame test, the biaxial tensile test or of a combined tension-shear test.
Experiment Study of Thermoforming of Plain Woven Composite (Carbon/Thermoplastics)
Authors: Yin Hong Ling , Peng Xiong Qi , Du Tong Liang , Chen Jun
Published: June 2013

By combining carbon woven fabric with thermoplastics grains, a thermo-stamping process is proposed for forming parts with complex double curvatures in one step, to implement the affordable application of fiber reinforced composites in high volume merchandises such as automotive industry. In the proposed thermo-stamping process, laminated carbon woven fabrics with thermoplastic grains are heated, and then transferred rapidly to a preheated mould for thermo-stamping, and cooled down to form the carbon fiber reinforced composite part. Various thermoplastics such as PP, PA6 and ABS are used as matrix material in the composite part. Experimental results including shear angle distribution in the fabric, deformed boundary profile of fabric with different original fiber orientation and forming defects are presented. It is demonstrated that high quality parts can be obtained with the proposed forming process, and defects are controllable. By using the proposed process and laminated structures, it is feasible to implement the high-volume and low-cost manufacturing of fiber reinforced composite parts.
Yield Stress in Semi-Solid Alloys – The Dependency on Time and Deformation History
Authors: Harboe Siri , Modigell Michael
Published: June 2013

An important aspect of the rheological characterization of semi-solid metals is the determination of the materials ability to exhibit yield stress. The yield stress is the stress level at which the material cease from purely elastic to plastic deformation. In semi-solid metal suspensions the yield stress is not a constant value, but depends on the transient state of the material. The investigation of yield stress in semi-solid metal alloys has been initiated in previous works, however, a profound understanding of the influence of the material history on the yield stress is so far lacking. In semi-solid metal suspensions, the physical cause of the yield stress is generally described by the formation of a particle "skeleton" structure which can hold a certain stress level without being subject to irreversible deformation. The yield stress in alloy suspensions can be described as a function of structural properties i.e. the solid fraction and the particle size, form and spatial distribution. It has been observed in previous works that the yield stress of semi-solid metals depends on the duration of resting time. It is generally assumed that this is due that as the material is resting, the particle network build up over time leading to an increase in the yield stress. In addition, we assume that the yield stress is also a function of the shear history as this affects the particle spatial distribution. The goal of the proposed work was to investigate the yield stress in semi-solid alloys including its dependency on the materials shear history and resting time. This was investigated both from a structural and a rheological point of view. The yield stress of the semi-solid alloys was measured with shear stress ramp and oscillation tests. Structural imaging measurements of quenched samples were performed to correlate structural parameters with the value of the yield stress. However, in semi-solid alloys, the experiments performed at a long time scale are influenced by aging of the material (Ostwald ripening). Therefore, rheological experiments were also performed with synthetic suspensions to investigate the long term yield stress dependencies without errors caused by the aging effects.
Thermal Barrier Coatings on Laser Surface Modified AISI H13 Tool Steel Using Atmospheric Plasma Spray Technique
Authors: Reza Mohammad S. , Aqida Syarifah N. , Mohd Toff Mohd Radzi , Brabazon Dermot
Published: June 2013

This paper presents yttria-stabilized zirconia (YSZ) coating deposition on laser surface modified H13 tool steel using atmospheric plasma spray (APS) technique. A Praxair Plasma Spray System with SG-100 gun was used to deposit coating materials on laser-modified H13 tool steel substrate surface. A bond coat layer material was NiCrAlY alloy while the top coat was yttria stabilized zirconia (YSZ) with powder size distribution range of-106 μm to +45 μm. A 23 design of experiment (DOE) was used to deposit bond coat and top coat powders with three controlled factors of input current, powder feed rate and stand-off-distance. The design was optimised for minimum porosity and maximum hardness. The coating thickness and percentage of porosity were measured using IM7000 inverted optical microscope. Hardness properties of top coating layer were measured by using MMT-X7 Matsuzawa Hardness Tester Machine with Vickers hardness scale. The microscopy findings indicated variations of coating thickness at different parameters settings. Samples at the highest current and powder feed rate and lowest stand-off distance settings produced a lower porosity percentage and higher hardness. A higher powder feed rate with the smallest stand-off-distance allowed melted powders to travel uniformly onto the substrate surface. These findings were significant to development of thermal barrier coatings on semi-solid forming die surface.
Hot Tensile Behavior of Superplastic and Commercial AA5083 Sheets at High Temperature and Strain Rate
Authors: Bruschi Stefania , Ghiotti Andrea , Michieletto Francesco
Published: June 2013

Since the last two decades, the automotive industry has dedicated an increasing attention to the manufacturing of sheet components made of high-resistant aluminium alloys; the superplastic AA5083 grade is currently utilized in both the conventional superplastic forming and the recently patented quick plastic forming, which assures higher productivity compared to that of superplastic forming, while the commercial AA5083 grade is rarely employed. The objective of the paper is to compare the hot tensile behaviour of commercial and fine-grained AA5083 sheets when processed at high temperature and strain rate, which are typical of hot stamping processes. The results are presented and commented in terms of flow stress, anisotropy, strain at failure, microstructural and hardness features as a function of temperature and strain rate. On the basis of the obtained results, the set of optimal forming conditions for the two grades is identified.
Topology Optimization of a Car Seat Frame
Authors: Oliveira José , Teixeira Pedro , Lobo Gilberto , Duarte João , Reis Ana
Published: June 2013

The optimization of consumer products through the use of numerical simulations has become a key factor to a continuously increasing requirement for time and cost efficiency, for quality improvement and materials saving, in many manufacturing areas such as automotive, aerospace, building, packaging and electronic industries. Environmental protection, fuel economy and safety specifications are today major concerns in automotive industry. Part of the overall strategy is a lower weight car which means increased performance, reduction of fuel consumption achieving a lower vehicle exhaust emissions to the environment. At the same time, the occupant safety must be continuously improved, as the safety specifications are more demanding. To meet these requirements, a call for new lightweight’s concepts and crash structures was raised, using lighter and/or stronger materials. In the last decade we have assisted to a development and application of high-strength steels and aluminum alloys in the manufacture of automotive structures. This paper presents a structural design problem of a car seat frame, aiming the desired weight reduction while satisfying a set of performance constraints. The numerical model of the seat frame has been developed and the numerical results were validated against experimental data obtained during static loading tests. Using the developed computational model, an optimized topology of the linear elastic structure has been determined, reaching a significant weight reduction.
Coextrusion and Mechanical Characterization of Aluminum Coated Mg-Profiles
Authors: Negendank Maik , Weber Constanze , Müller Sören , Reimers Walter
Published: June 2013

Due to their low density and high specific strengths Mg-alloys provide an excellent potential to be used for light weight constructions. However, their equilibrium potential is very low resulting in relatively low corrosion resistance, especially in contact with other, more noble metals. In order to separate Mg from a corrosive environment hybrid billets with Al-alloy coating and AZ31-core were coextruded. Thus, the extrusion and coating of Mg-profiles can be done in a single production step, resulting in aluminum coated Mg-profiles. The influence of the extrusion ratio as well as of different die angles on the formation of diffusion layers at the interface was investigated. Furthermore the phases formed in the diffusion zones were analyzed using EDS and synchrotron XRD. Additionally, FEM-simulations were conducted in order to reveal the material flow of core and shell material during the forming process and to identify differences in using different die angles. The FEM-results were verified by comparison with the real extrusion experiments. Finally, the shear strengths of the produced compounds were evaluated in push-out tests.
Velocity Field in Direct, Indirect and Friction Assisted Extrusion of Al
Authors: Torabzadeh Khorasani Sepinood , Valberg Henry
Published: June 2013

This study investigates the velocity fields that are descriptive for the forward, backward and friction assisted extrusion of axisymmetric rods. The Avitzur theory was used to calculate the velocity field and strain rate in extrusion of Al alloys. Several simulations have also been performed by using finite element analysis (FEA) with DEFORM 2D, in order to find the admissible velocity field for different conditions of friction including high and low friction. The results from FEA and theory of axisymmetric extrusion are compared to see if there is good agreement. The correlation between the data obtained by theory and FEA is discussed.
Study of Morphology Wear Model of Moulds from Alloys of Aluminium EN AW-6082 in Injection Process
Authors: Pereira Alejandro , Hernández Primo , Martínez Javier , Pérez José A. , Mathia Thomas
Published: June 2013

The main objective of this research is study the wear of a mould, made in easy machining material; aluminium EN AW-6082 T4 and the surface characterization of mould cavity, used in a polymeric manufacturing process, after several injection cycles. To evaluate the effectiveness of this materials in the plastic injection process, a test part with different thicknesses and shapes was designed and some inserts of aluminium were made. In the way of plastic material, a 30 % fiberglass reinforced polyamide PA6 has been employed in the experimental procedure. A reusable injection mould was used and surface measurements of mould cavity have been performed after 9200 cycles. The surface topography has been measured by using optical interferometry profiling technology and there have also been obtained roughness and surface parameters according to ISO 25178 and EUR15178N. In order to surface characterization, different areas of the mould cavity with different geometries, has been analysed. The behaviour of wear rate has been analysed by the study of the evolution of the surface parameters and functional parameters in different points of the surface mould.
Accuracy of Transferring Microparts in a Multi Stage Former
Authors: Mahshid Rasoul , Hansen Hans Nørgaard , Arentoft Mogens
Published: June 2013

Many fasteners used in electromechanical systems are micro metal parts which should be manufactured with high accuracy and reliability and in large quantities. Micro forming is promising to fulfill these demands. This research focuses on investigating a gripping unit in a multi stage former, as the positioning unit was discussed earlier. The parameters which play important roles in the gripping unit will be discussed and the precision and reproducibility evaluated to show the performance of the unit. This includes two different tests. The first test will show how accurately the unit can locate the parts and the second one is intended to depict how the unit transfers the parts with different diameters with respect to the front profile of the fingers. The experiments showed that the manipulator can handle the parts with 7 µm accuracy, 2 µm reproducibility and 9µm uncertainty for a 20mm distance between two adjacent stations.
Surrogate POD Models for Parametrized Sheet Metal Forming Applications
Authors: Mohamed Hamdaoui , Le Quilliec Guénhaël , Breitkopf Piotr , Villon Pierre
Published: June 2013

The aim of this work is to present a POD (Proper Orthogonal Decomposition) based surrogate approach for sheet metal forming parametrized applications. The final displacement field for the stamped work-piece computed using a finite element approach is approximated using the method of snapshots for POD mode determination and kriging for POD coefficients interpolation. An error analysis, performed using a validation set, shows that the accuracy of the surrogate POD model is excellent for the representation of finite element displacement fields. A possible use of the surrogate to assess the quality of the stamped sheet is considered. The Green-Lagrange strain tensor is derived and forming limit diagrams are computed on the fly for any point of the design space. Furthermore, the minimization of a cost function based on the surrogate POD model is performed showing its potential for solving optimization problems.
Damage Material Parameters Identification Using the ANN-GA Method and the Bulge Test
Authors: Aguir Hamdi , Bel Hadj Salah Hedi
Published: June 2013

The simulation of the metal forming processes requires accurate constitutive models describing the material behaviour at finite strain, and taking into account several conditions. The choice of a rheological model and the determination of its parameters should be made from a test that generates such conditions. The major difficulty encountered is that there is no experimental test satisfying all these criteria. The use of more than one test seems well adapted, and is utilized to characterize the rheological behaviour at operating conditions corresponding to metal forming applications. Inverse analysis is then considered. Therefore, the difficulty lies with the long computing time that was taken when an optimization procedure is coupled with a finite element computation (FEC) to identify the material parameters. In order to solve the computing time problem, this paper proposes a hybrid identification method based on an artificial neural network and a genetic algorithm (ANN-GA). The proposed strategy is applied to identify the damage material parameters of the AISI 304 steel and using the bulge test.
Application of Tube Hydroforming in Square Cross-Section Die for Inverse Identification Method Validation
Authors: Khalfallah Ali , Zribi Temim , Salah Hedi Belhadj
Published: June 2013

Tube hydroforming processes are an excellent way for manufacturing reduced weight parts with complex shapes in widespread fields. Accurate numerical simulation of tube hydroforming process is particularly based on precise material parameters deduced from experimental tests. The free bulge test is widely employed for the parameter identification of tubular material behavior models by means of analytical [1] and numerical methods [2]. In this context, an inverse identification methodology using free bulge tests was developed. These tests were carried out by means of a new home-designed and manufactured bulge forming machine. The objective of this work is the validation of the inverse identification method using tube hydroforming in square cross-section die. The analysis of this particular hydroforming process with respect to material parameters is performed. For this purpose, circular section tubes made of low carbon steel S235 and aluminum alloy AA6063-O are hydroformed against square-cross sectional die using our bulge forming machine. Afterwards, FE model is constructed to simulate square-sectional hydroformed parts. The influence of some parameters, such as strain hardening exponent, anisotropy parameter and friction coefficient, on numerical square cross-sectional hydroformed part thickness is analyzed. It permits to assess the sensitivity of the thickness relative to used material parameters in the FE model. In order to validate the inverse identification procedure for both materials, experimental thicknesses along the profile of cross-sectional hydroformed parts are measured and compared with the corresponding numerical thicknesses predicted by FE model. It is proven after analyzing the obtained results that the chosen response, i.e. thickness distribution along the profile of the tube hydroforming against the square cross-section die, used for the validation is sensitive to the identified material properties. Particularly, it is demonstrated for low carbon steel S235 that numerical thickness is in good agreement with experimental data. However, for aluminum alloy AA6063-O, a discrepancy between experimental and predicted thicknesses is noticed. Anyway, it is demonstrated that inverse identification approach leads to sufficiently accurate parameters used for numerical tube hydroforming simulations. Furthermore, it seems that Hill48’s yield criterion is more suitable for describing steels plastic behavior than aluminum alloys for tube hydroforming processes. Concerning aluminum alloy, certainly the choice of appropriate yield criterion is of paramount importance on the prediction of tubular plastic behavior in tube hydroforming. Consequently, it is shown that the use of simple tube hydroforming in square-section die is suitable for the validation of FE model which is identified by inverse method using free bulge test.
Effect of Welding Parameters on AA8090 Al-Li Alloy FSW T-Joints
Authors: Lertora Enrico , Mandolfino Chiara , Gambaro Carla
Published: June 2013

In aeronautics and aerospace construction, whenever a seam is needed between aluminum alloy parts, riveting, nailing or bolting are the preferred methods of junction. Friction stir welding technology has made possible the realization of high strength aluminum alloy joints, which are normally considered non-weldable with conventional welding techniques.
Effect of Surface Pretreatment on the Performance of Adhesive-Bonded Joints
Authors: Mandolfino Chiara , Lertora Enrico , Gambaro Carla
Published: June 2013

This paper presents a systematic investigation of the influence of sandblasting pretreatment parameters on the surface roughness and mechanical characteristics of adhesive-bonded joints. The preliminary surface treatment in a bonding process has two important aims: first of all, it eliminates contaminants (dust, grease, humidity and corrosion products) which can modify the wettability of the substrate, then it increases surface roughness and, consequently, the contact area between substrate and adhesive, creating a mechanical interlocking that maximizes adhesion. To enhance the strength and avoid the de-adhesive failure of the joint, it is therefore advisable to increase the contact substrate-adhesive by a mechanical treatment of sanding, grinding or preferably sandblasting, usually considered one of the most effective methods to control the desired level of surface roughness and joint strength. This process, apparently easy to manage, is controlled by a great number of operating parameters, which all contribute to creating a good result. With the aim of evaluating the influence that some of these parameters have on the mechanical characteristics of adhesive-bonded joints, an experimental campaign was carried out. In particular, a steel substrate, an epoxy adhesive and various types of sand, different in nature and granulometry were used. The variable parameters for the execution of blasting are sand, impact angle and pressure. The assessments departed from an investigation into their effect on surface roughness and thereafter the mechanical properties of the bonded joints were analyzed.
Does spruce budworm (Lepidoptera: Tortricidae) rearing diet influence larval parasitism?
Authors: Seehausen M. Lukas , Régnière Jacques , Bauce Éric
Published: June 2013

Artificial diet is commonly used to rear the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), in the laboratory. While its effect on spruce budworm performance is relatively well studied, no information exists about the influence of rearing diet on larval parasitism. In this study, spruce budworm larvae reared in the laboratory on artificial diet or balsam fir, Abies balsamea (Linnaeus) Miller (Pinaceae), foliage were introduced in the field to compare parasitism. Additionally, a laboratory choice test was conducted with the larval parasitoid Tranosema rostrale (Brischke) (Hymenoptera: Ichneumonidae). No significant influence of spruce budworm rearing diet on parasitism in the field was found. However, in the laboratory, T. rostrale attacked significantly more foliage-fed larvae. We conclude that even if initial differences in parasitism may exist between diet-fed and foliage-fed larvae in the laboratory, spruce budworm larvae reared on artificial diet can be used in field studies investigating parasitism of wild spruce budworm populations without concern that the food source would affect parasitism.
Combined Inhibition of Complement (C5) and CD14 Markedly Attenuates Inflammation, Thrombogenicity, and Hemodynamic Changes in Porcine Sepsis
Authors: Barratt-Due Andreas , Thorgersen Ebbe B. , Egge Kjetil , Pischke Søren , Sokolov Andrey , Hellerud Bernt C. , Lindstad Julie K. , Pharo Anne , Bongoni Anjan K. , Rieben Robert , Nunn Miles , Scott Helge , Mollnes Tom E.
Published: June 2013

Complement and the TLR family constitute two important branches of innate immunity. We previously showed attenuating effects on inflammation and thromogenicity by inhibiting the TLR coreceptor CD14 in porcine sepsis. In the present study, we explored the effect of the C5 and leukotriene B4 inhibitor Ornithodoros moubata complement inhibitor (OmCI; also known as coversin) alone and combined with anti-CD14 on the early inflammatory, hemostatic, and hemodynamic responses in porcine Escherichia coli–induced sepsis. Pigs were randomly allocated to negative controls (n = 6), positive controls (n = 8), intervention with OmCI (n = 8), or with OmCI and anti-CD14 (n = 8). OmCI ablated C5 activation and formation of the terminal complement complex and significantly decreased leukotriene B4 levels in septic pigs. Granulocyte tissue factor expression, formation of thrombin–antithrombin complexes (p < 0.001), and formation of TNF-α and IL-6 (p < 0.05) were efficiently inhibited by OmCI alone and abolished or strongly attenuated by the combination of OmCI and anti-CD14 (p < 0.001 for all). Additionally, the combined therapy attenuated the formation of plasminogen activator inhibitor-1 (p < 0.05), IL-1β, and IL-8, increased the formation of IL-10, and abolished the expression of wCD11R3 (CD11b) and the fall in neutrophil cell count (p < 0.001 for all). Finally, OmCI combined with anti-CD14 delayed increases in heart rate by 60 min (p < 0.05) and mean pulmonary artery pressure by 30 min (p < 0.01). Ex vivo studies confirmed the additional effect of combining anti-CD14 with OmCI. In conclusion, upstream inhibition of the key innate immunity molecules, C5 and CD14, is a potential broad-acting treatment regimen in sepsis as it efficiently attenuated inflammation and thrombogenicity and delayed hemodynamic changes.
Phl p 1–Specific Human Monoclonal IgE and Design of a Hypoallergenic Group 1 Grass Pollen Allergen Fragment
Authors: Levin Mattias , Rydnert Frida , Källström Eva , Tan Lor Wai , Wormald Peter J. , Lindstedt Malin , Greiff Lennart , Ohlin Mats
Published: June 2013

Detailed understanding of how Abs of the IgE isotype interact with allergen at the onset of an allergic reaction is of great importance for deciphering mechanisms involved in the development of disease and may aid in the design of hypoallergenic variants. In this study, we have used a set of human monoclonal IgE Abs derived from the repertoires of allergic individuals, specific for the major timothy grass pollen allergen Phl p 1, to gain detailed information on the interaction between Abs and allergen. These allergen-specific IgE are to varying degrees cross-reactive toward both different allergen isoforms and various group 1 allergens originating from other grass species. The usage of human monoclonal IgE, as an alternative to polyclonal preparations or mouse Abs, allowed us to locate several important IgE-binding epitopes on the C-terminal domain of Phl p 1, all clustered to an IgE-binding “hot spot.” By introducing three mutations in the IgE-binding area of the C-terminal domain we were able to significantly reduce its reactivity with serum IgE. In conclusion, our study shows the great potential of using human monoclonal IgE as a tool for studies of the molecular interactions taking place during allergic responses. Furthermore, we present a novel IgE-hyporeactive fragment with the potential to be used as a safer hypoallergenic alternative in specific immunotherapy than the pollen extracts used today.
An experience sampling study of physical activity and positive affect: investigating the role of situational motivation and perceived intensity across time
Authors: Guérin Eva , Fortier Michelle S. , Sweet Shane N.
Published: June 2013

The nature of the association between physical activity and positive affect is complex, prompting experts to recommend continued examination of moderating variables. The main purpose of this 2-week field study was to examine the influence of situational motivational regulations from self-determination theory (SDT) on changes in positive affect from pre- to post- to 3-hours post-physical activity. Another purpose was to clarify the relationship between physical activity intensity [i.e., Ratings of Perceived Exertion (RPE)] and positive affect at the stated time points. This study employed an experience sampling design using electronic questionnaires. Sixty-six healthy and active, multiple-role women provided recurrent assessments of their physical activity, situational motivation, and positive affect in their everyday lives over a 14-day period. Specifically, measures were obtained at the three time points of interest (i.e., pre-, post-, 3-hours post-physical activity). The data were analyzed using multilevel modeling. Results showed that intrinsic motivation was related to post-physical activity positive affect while the influence of identified regulation appeared 3-hours post-physical activity. In addition, RPE, which was significantly predicted by levels of introjection, was more strongly associated with an increase in positive affect post-physical activity than three hours later. The theoretical implications of these findings vis-à vis SDT, namely in regards to a viable motivational sequence predicting the influence of physical activity on affective states, are discussed. The findings regarding the differential influences of RPE and motivational regulations carries applications for facilitating women’s well-being.
Feeding Problems in Healthy Young Children: Prevalence, Related Factors and Feeding Practices
Authors: Benjasuwantep Banchaun , Chaithirayanon Suthida , Eiamudomkan Monchutha
Published: June 2013

The aim of this study was to determine the prevalence, characteristics, and factors related to feeding problems among normal children, and the differences in feeding practices between those with and without feeding problems. Caregivers of 402 healthy children aged between one and four years of age were interviewed by pediatricians involved in the research. Data included the child’s medical history, food intake within a day, and feeding behaviors and practices. Parental socio-economic and demographic information, as well as information on parental education and occupation, and their concerns about feeding their children, was collected. Physical examination and anthropometric measurements were taken. The percentage of children identified as having feeding problems was 26.9%. The first child of a family had an increased risk of having feeding problems [P=0.032, odds ratio 1.68, 95% confidence interval (95%CI) 1.04-2.71]. Children with feeding problems were fed less frequently, were less likely to be fed at their own table or at the family table, and had mealtimes longer than 30 min when compared with children without feeding problems (P=0.015, 0.004 and 0.025, respectively). The results highlight that feeding problems in normally developing children are common. During consultations about feeding issues, pediatricians should focus on families with a first child. Topics such as frequency of meals per day, duration of meal-times, and appropriate places for feeding should be discussed.
Primary Ovary Choriocarcinoma: Individual DNA Polymorphic Analysis as a Strategy to Confirm Diagnosis and Treatment
Authors: Exman Pedro , Takahashi Tiago Kenji , Gattás Gilka F. , Cantagalli Vanessa Dionisio , Anton Cristina , Nalesso Fernando , Diz Maria Del Pilar Estevez
Published: June 2013

Primary choriocarcinoma of the ovary is rare. Furthermore, this tumor can arise from gestational tissue or pure germ cells of the ovary, with the latter resulting in non-gestational choriocarcinoma. While the clinical characteristics and histology of both tumor types are identical, differentiation of these tumors is necessary for effective treatment. One strategy for the differentiation of these tumors types is to assay for the presence of paternal DNA. Accordingly, in the present case, a patient with primary choriocarcinoma of the ovary with a non-gestational origin was confirmed by DNA analysis. The patient subsequently exhibited an excellent response to chemotherapy, and following surgery, achieved complete remission. A pathological analysis of surgical specimens further confirmed the absence of tumor.
Cutaneous metastasis in esophageal squamous cell carcinoma
Authors: Baijal Rajiv , Hassan Praveenkumar , Jain Mayank , Gupta Deepak , Shah Nimish
Published: June 2013

Cutaneous metastasis from internal malignancies are common in breast cancer, pulmonary malignancies and melanomas. The primary site of metastases has been reported to the chest and abdomen. We are hereby reporting rare case of cutaneous metastasis in esophageal cancer.
Ovarian stromal tumor with minor sex cord elements with coexistent endometrial carcinoma
Authors: Kumar Sunesh , Mathur Sandeep , Subbaiah Murali , Singh Lavleen
Published: June 2013

Ovarian stromal tumor with minor sex cord elements is a rare tumor. It is composed of predominantly fibrothecomatous tumor with scattered minor sex cord elements in less than 10% of the tumor area. These tumors may be hormonally active and predispose to carcinoma endometrium. A case of ovarian fibroma-thecoma with minor sex cord elements in which coexistent endometrial carcinoma was also discovered is being reported. Though thecoma may be a predisposing factor for endometrial cancer, meticulous histopathological examination of the ovary may reveal additional sources of estrogen like granulosa cell aggregates as in our patient. Such patients would require long-term follow-up to detect any recurrence of granulosa cell tumor.
Narcotics in Rheumatology
Authors: Tehrani Mahsa , Aguiar Mathia , Katz James D.
Published: June 2013

Patients with rheumatic conditions often suffer from related chronic pain. When first-line traditional medications such as acetaminophen and anti-inflammatory medications do not suffice, then other options are needed. The traditional medications may ultimately not provide sufficient pain relief, or alternatively, they can pose as a contraindication due to underlying hypertension, renal, and/or hepatic disease. Therefore, narcotics are an alluring alternative, which if used in a multidisciplinary and systematic approach to the patient, can prove to be quite beneficial in the lives of these patients.
Analysis of a winter regional haze event and its formation mechanism in the North China Plain
Authors: Zhao X. J. , Zhao P. S. , Xu J. , Meng, W. , Pu W. W. , Dong F. , He D. , Shi Q. F.
Published: June 2013

Abstract. A regional haze episode occurred in the Beijing, Tianjin and Hebei province (BTH) area in the North China Plain (NCP) from 16 to 19 January 2010. Data were collected and analyzed during the time frame of 14 through 23 January 2010 to include the haze event. The increase of secondary inorganic pollutants (SO42−, NO3−, NH4+) in PM2.5 was observed simultaneously at four sites, especially in the plain area of the BTH, which could be identified as a common characteristic of pollution haze in east China. The sulfate and nitrate in PM2.5 were mainly formed through the heterogeneous reaction process in the urban area. The organic matter (OM) increased more significantly at the Chengde (CD) site than the other three sites in the plain area. The secondary organic aerosols only existed during haze days at CD but in both haze and non-haze days at the other three sites, which suggested the greater regional impact of secondary formation process during the haze episode. The secondary formation of aerosol was one important formation mechanism of haze. The strong temperature inversion and descending air motions in the planetary boundary layer (PBL) allowed pollutants to accumulate in a shallow layer. The weak surface wind speed produced high pollutants concentration within source regions. The accumulation of pollutants was one main factor in the haze formation. The enhanced southwest wind in the last period of this episode transported pollutants to the downwind area and expanded the regional scope of the haze.
Antarctic ozone variability inside the Polar Vortex estimated from balloon measurements
Authors: Parrondo M. C. , Gil M. , Yela M. , Johnson B. J. , Ochoa H. A.
Published: June 2013

Abstract. 13 yr of ozonesoundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analyzed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during winter time when satellites and ground-based instruments based on solar radiation are lacking. The work is focused on ozone loss rate variability (August–October) and its recovery (November–December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, about day 220 (mid August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years while warms winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss in the layer where maximum depletion occurs takes place before the sun has arrived as a result of transport of lower latitude air masses, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole Station (SPS) for the same altitude range and for 9 yr of overlapping data. Unexpected results show more than 25% larger ozone loss rate at SPS than at Belgrano. It has been found that the accumulated hours of sunlight are the dominant factor driving the ozone loss rate. According to the variability of the ozone-hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12–24 km layer remained in November for the longest vortex, while years when the final stratospheric warming took "very early", mean integrated ozone rises up to 160–180 DU.
Nitrous oxide emissions 1999–2009 from a global atmospheric inversion
Authors: Thompson R. L. , Chevallier F. , Crotwell A. M. , Dutton G. , Langenfelds R. L. , Prinn R. G. , Weiss R. F. , Tohjima Y. , Nakazawa T. , Krummel P. B. , Steele L. P. , Fraser P. , Ishijima K. , Aoki S.
Published: June 2013

Abstract. N2O surface fluxes were estimated for 1999 to 2009 using a time-dependent Bayesian inversion technique. Observations were drawn from 5 different networks, incorporating 59 surface sites and a number of ship-based measurement series. To avoid biases in the inverted fluxes, the data were adjusted to a common scale and scale offsets were included in the optimization problem. The fluxes were calculated at the same resolution as the transport model (3.75° longitude × 2.5° latitude) and at monthly time resolution. Over the 11 yr period, the global total N2O source varied from 17.5 to 20.1 Tg a−1 N. Tropical and subtropical land regions were found to consistently have the highest N2O emissions, in particular, in South Asia (20% of global total), South America (13%) and Africa (19%), while emissions from temperate regions were smaller, Europe (6%) and North America (7%). A significant multi-annual trend in N2O emissions (0.045 Tg a−2 N) from South Asia was found and confirms inventory estimates of this trend. Considerable inter-annual variability in the global N2O source was observed (0.8 Tg a−1 N, 1 standard deviation, SD) and was largely driven by variability in tropical and subtropical soil fluxes, in particular in South America (0.3 Tg a−1 N, 1 SD) and to a lesser extent in Africa (0.3 Tg a−1 N, 1 SD). Notable variability was also found for N2O fluxes in the tropical and southern oceans (0.15 and 0.2 Tg a−1 N, 1 SD, respectively). Inter-annual variability in the N2O source correlates strongly with ENSO, where El Niño conditions are associated with lower N2O fluxes from soils and from the ocean and vice-versa for La Niña conditions.
Understanding primary and secondary sources of ambient carbonyl compounds in Beijing using the PMF model
Authors: Chen W. T. , Shao M. , Lu S. H. , Wang M. , Zeng L. M.
Published: June 2013

Abstract. Carbonyls are important intermediates in atmospheric photochemistry. To determine the relative contributions of primary and secondary carbonyl sources in Beijing, carbonyls and other trace gases were measured at Peking University in winter and summer. The Positive Matrix Factorization (PMF) model was used for source apportionment. As volatile organic compounds (VOCs) will undergo photochemical processes in the atmosphere, and such processes may interfere with factors identification, the relationships between the contributions of the resolved PMF factors to each non-methane hydrocarbon (NMHC) species and its kOH value were used to distinguish between photochemically aged factors and fresh factors. As the result of PMF, five factors were resolved in winter, and two of them were identified as sources of photochemically aged emissions. In summer, four factors were resolved, including an aged factor. Carbonyls in the aged factors were simulated by NMHCs consumption and the corresponding carbonyl production yields, and the simulated abundances agreed well with the results obtained by PMF. The source apportionment results indicated that secondary formation was the major source of carbonyls in both seasons, with the contribution of 51.2% and 46.0%. For the three major carbonyl species, primary anthropogenic sources contributed 28.9% and 32.3% to ambient formaldehyde, 53.7% and 41.6% to acetaldehyde, 68.1% and 56.2% to acetone in winter and summer, respectively.
Characterization of the planetary boundary layer height and structure by Raman lidar: comparison of different approaches
Authors: Summa D. , Di Girolamo P. , Stelitano D. , Cacciani M.
Published: June 2013

Abstract. The Planetary Boundary Layer (PBL) includes the portion of the atmosphere which is directly influenced by the presence of the Earth's surface. Aerosol particles trapped within the PBL can be used as tracers to study the boundary-layer vertical structure and time variability. As a result of this, elastic backscatter signals collected by lidar systems can be used to determine the height and the internal structure of the PBL. The present analysis considers three different methods to estimate the PBL height. A first method is based on the determination of the first order derivative of the logarithm of the range-corrected elastic lidar signals. Estimates of the PBL height for specific case studies obtained from this approach are compared with simultaneous estimates from the potential temperature profiles measured by radiosondes launched simultaneously to lidar operation. Additional estimates of the boundary layer height are based on the determination of the first order derivative of the range-corrected rotational Raman lidar signals. This latter approach results to be successfully applicable also in the afternoon-evening decaying phase of the PBL, when the effectiveness of the approach based on the elastic lidar signals may be compromised or altered by the presence of the residual layer. Results from these different approaches are compared and discussed in the paper, with a specific focus on selected case studies collected by the University of Basilicata Raman lidar system BASIL during the Convective and Orographically-induced Precipitation Study (COPS).
Quality aspects of the measurements of a wind profiler in a complex topography
Authors: Maruri M. , Romo J. A. , Gomez L.
Published: June 2013

Abstract. It is well known amongst the scientific community that some remote sensing instruments have assumed that sample volumes present homogeneous conditions within a defined meteorological profile. At complex topographic sites and under extreme meteorological conditions, this assumption may be fallible depending on the site, and it is more likely to fail in the lower layers of the atmosphere. This piece of work tests the homogeneity of the wind field over a boundary layer wind profiler radar located in a complex terrain on the coast, under different meteorological conditions. The results reveal the qualitative importance of being aware of the deviations of this homogeneity assumption and evaluate its effect on the final product. Patterns of behaviour in data have been identified in order to simplify the analysis of the complex signal registered. The quality information obtained from the homogeneity study under different meteorological conditions is useful to look for the best alternatives the system can offer to build wind profiles. Finally, the results are also to be considered in order to integrate them in a quality algorithm implemented at product level.
Mercury dynamics in the Rocky Mountain, Colorado, snowpack
Authors: Faïn X. , Helmig D. , Hueber J. , Obrist D. , Williams M. W.
Published: June 2013

Abstract. Gaseous elemental mercury (GEM) was monitored at the Niwot Ridge (NWT) Long-Term Ecological Research (LTER) site (Colorado, USA, 40° N) from interstitial air extracted from the snowpack at depths ranging from the snow surface to 10 cm above the soil. A highly dynamic cycling of mercury (Hg) in this mid-latitude snowpack was observed. Patterns were driven by both GEM production in surface snow and GEM destruction in the deeper snowpack layers. Thorough mixing and vertical transport processes were observed through the snowpack. GEM was photochemically produced near the snow-air interface throughout the entire winter, leading to enhanced GEM levels in interstitial air of surface snow of up to 8 ng m−3. During low-wind periods, GEM in surface snow layers remained significantly above ambient air levels at night as well, which may indicate a potential weak GEM production overnight. Analyses of vertical GEM gradients in the snowpack show that surface GEM enhancements efficiently propagated down the snowpack, with a temporal lag in peak GEM levels observed with increasing depth. Downward diffusion was responsible for much of these patterns, although vertical advection also contributed to vertical redistribution. Destruction of GEM in the lower snowpack layers was attributed to dark oxidation of GEM. Analysis of vertical GEM / CO2 flux ratios indicated that this GEM destruction occurred in the snow and not in the underlying soil. The strong, diurnal patterns of photochemical GEM production at the surface ultimately lead to re-emission losses of deposited Hg back to the atmosphere. The NWT data show that highest GEM surface production and re-emissions occur shortly after fresh snowfall, which possibly resupplies photoreducible Hg to the snowpack, and that photochemical GEM reduction is not radiation-limited as it is strong even on cloudy days.