bluuebunny/crossref_metadata_2025 huggingface dataset:
Knockdown of Long Noncoding RNA uc.338 by siRNA Inhibits Cellular Migration and Invasion in Human Lung Cancer Cells
Authors: Gao Xuexin , Gao Xuezhen , Li Chao , Zhang Yukun , Gao Lei
Published: September 2016

Lung cancer remains a critical health concern worldwide. Long noncoding RNAs with ultraconserved elements have recently been implicated in human tumorigenesis. The present study investigated the role of ultraconserved element 338 (uc.338) in the regulation of cell proliferation and
metastasis in human lung cancer. Our data showed that the expression of uc.338 in lung cancer was remarkably increased in vivo and in vitro. Depletion of uc.338 with specific siRNA interference retarded the cell proliferative rate in lung cancer cell lines NCI-H929 and H1688. Furthermore,
knockdown of uc.338 caused cell cycle arrest in the G0/G1 phase in both cell lines. Transwell assays showed that inhibition of uc.338 notably decreased migration and invasion in NCI-H929 and H1688 cells. Moreover, uc.338 depletion decreased the expression of cyclin B1,
Cdc25C, Snail, vimentin, and N-cadherin while increasing the protein level of E-cadherin, shown with Western blot analysis. These results suggested the pro-oncogenic potential of uc.338 in lung cancer, which might provide novel clues for the diagnosis and treatment of lung cancer in the clinic.
Knockdown of UBE2T Inhibits Osteosarcoma Cell Proliferation, Migration, and Invasion by Suppressing the PI3K/Akt Signaling Pathway
Authors: Wang Yu , Leng Hui , Chen Hui , Wang Lei , Jiang Nan , Huo Xin , Yu Bin
Published: September 2016

Ubiquitin-conjugating enzyme E2T (UBE2T), a member of the E2 family, was found to be overexpressed in a great many cancers such as bladder cancer, lung cancer, and prostate cancer. However, there have been no reports on the role of UBE2T in osteosarcoma. In this study, we tried to make
the effects of UBE2T on osteosarcoma clear. The study results showed that UBE2T was overexpressed in osteosarcoma tissues and cell lines. Moreover, UBE2T knockdown inhibited osteosarcoma cell proliferation, migration, and invasion. We also observed that UBE2T downregulation could suppress
the activity of the PI3K/Akt signaling pathway. Therefore, we concluded that UBE2T exerted its inhibitory effects on osteosarcoma cells via suppressing the PI3K/Akt signaling pathway. These findings indicated that UBE2T may be a potential therapeutic target for osteosarcoma treatment.
CHAOS. III. GAS-PHASE ABUNDANCES IN NGC 5457
Authors: Croxall Kevin V. , Pogge Richard W. , Berg Danielle A. , Skillman Evan D. , Moustakas John
Published: September 2016

We present Large Binocular Telescope observations of 109 H ii regions in NGC 5457 (M101) obtained with the Multi-Object Double Spectrograph. We have robust measurements of one or more temperature-sensitive auroral emission lines for 74 H ii regions, permitting the measurement of “direct” gas-phase abundances. Comparing the temperatures derived from the different ionic species, we find: (1) strong correlations of T[N ii] with T[S iii] and T[O iii], consistent with little or no intrinsic scatter; (2) a correlation of T[S iii] with T[O iii], but with significant intrinsic dispersion; (3) overall agreement between T[N ii], T[S ii], and T[O ii], as expected, but with significant outliers; (4) the correlations of T[N ii] with T[S iii] and T[O iii] match the predictions of photoionization modeling while the correlation of T[S iii] with T[O iii] is offset from the prediction of photoionization modeling. Based on these observations, which include significantly more observations of lower excitation H ii regions, missing in many analyses, we inspect the commonly used ionization correction factors (ICFs) for unobserved ionic species and propose new empirical ICFs for S and Ar. We have discovered an unexpected population of H ii regions with a significant offset to low values in Ne/O, which defies explanation. We derive radial gradients in O/H and N/O which agree with previous studies. Our large observational database allows us to examine the dispersion in abundances, and we find intrinsic dispersions of 0.074 ± 0.009 in O/H and 0.095 ± 0.009 in N/O (at a given radius). We stress that this measurement of the intrinsic dispersion comes exclusively from direct abundance measurements of H ii regions in NGC 5457.
SPIN–ORBIT MISALIGNMENT AS A DRIVER OF THE KEPLER DICHOTOMY
Authors: Spalding Christopher , Batygin Konstantin
Published: September 2016

During its five-year mission, the Kepler spacecraft has uncovered a diverse population of planetary systems with orbital configurations ranging from single-transiting planets to systems of multiple planets co-transiting the parent star. By comparing the relative occurrences of multiple to single-transiting systems, recent analyses have revealed a significant over-abundance of singles. Dubbed the “Kepler Dichotomy,” this feature has been interpreted as evidence for two separate populations of planetary systems: one where all orbits are confined to a single plane, and a second where the constituent planetary orbits possess significant mutual inclinations, allowing only a single member to be observed in transit at a given epoch. In this work, we demonstrate that stellar obliquity, excited within the disk-hosting stage, can explain this dichotomy. Young stars rotate rapidly, generating a significant quadrupole moment, which torques the planetary orbits, with inner planets influenced more strongly. Given nominal parameters, this torque is sufficiently strong to excite significant mutual inclinations between planets, enhancing the number of single-transiting planets, sometimes through a dynamical instability. Furthermore, as hot stars appear to possess systematically higher obliquities, we predict that single-transiting systems should be relatively more prevalent around more massive stars. We analyze the Kepler data and confirm this signal to be present.
Anti-proteolytic activity of Ganoderma lucidum methanol extract against Pseudomonas aeruginosa
Authors: El Zawawy Nessma Ahmed , Ali Sameh Samir
Published: September 2016

Introduction: Protease enzyme is considered one of the most serious virulence factors produced by extended-spectrum β-lactamase-producing and multidrug-resistant Pseudomonas aeruginosa (ESβLMDRPA) clinical isolates. Methodology: The antibacterial activity of methanol extract of Ganoderma lucidum fruiting bodies was tested against a protease-producing ESβLMDRPA clinical isolate, showing its mode of action. Results: The extract showed high antibacterial activity. Its effect on purified protease indicated a reversible non-competitive protease inhibition (kis= 0.45 mg/mL). Conclusions: The G. lucidum extract could be a promising anti-proteolytic active against ESβLMDRPA. It may form a primary platform for further phytochemical studies and development of new drugs for therapy of skin burn infections.
Chagas disease prevalence in pregnant women: migration and risk of congenital transmission
Authors: Kolliker-Frers Rodolfo A , Insua Ivan , Razzitte Gabriela , Capani Francisco
Published: September 2016

Introduction: Argentina has been a preferential target for Bolivian immigrants for decades. The relatively recent migratory flux includes Germany, France, the United States, Australia, Japan, and some Latin American countries. The aim of this cross-sectional study was to describe the prevalence of Chagas disease in pregnant women, analyzing the Bolivian-specific Chagas prevalence as the main contributor of migratory populations from Chagas disease-endemic areas to Buenos Aires city, Argentina, and to evaluate the impact of these migrant influxes on the process of the "urbanization" of the disease in reference hospital José Maria Ramos Mejia (JMRM). Methodology: Overall, 21,332 pregnant women (100%) between 15 and 49 years of age derived from the public maternity service of JMRMH were studied. Serology data was obtained from registered serological diagnosis data, consisting of three different serological tests performed at the Public Parasitology Unit. Results: Although general prevalence decreased during the analyzed period, the specific prevalence of pregnant women from Bolivian origin showed a sustained growth during 1983–2013. Solely 5% of the total pregnant women population from Bolivia contributed to one third of the total Chagas prevalence. Conclusions: This study showed that a cohort of pregnant women from Bolivia who attended JMRMH during the period 1983–2007 constituted a population at risk for congenital transmission. Increased migration from endemic areas of Bolivia might potentially increase the prevalence of Chagas disease among pregnant women. In addition, this study highlights the importance to analyze specific prevalence according to endemic areas to determine the profiles of potential hidden prevalence.
Molecular genotyping of duck hepatitis A viruses (DHAV) in Vietnam
Authors: Doan Huong Thi Thanh , Le Xuyen Thi Kim , Do Roan Thi , Hoang Chau Thi Minh , Nguyen Khue Thi , Le Thanh Hoa
Published: September 2016

Introduction: The aim of this study was to identify the genetic characteristics and molecular genotyping of duck hepatitis A virus (DHAV) isolated in Vietnam during 2009–2013. Methodology: Thirty duckling livers from outbreaks between 2009 and 2013 in seven provinces were collected and identified by polymerase chain reaction (PCR). Then, VP1 genes of eleven positive samples and two attenuated vaccine strains were sequenced and analyzed. Results: Genotypic and phylogenetic analyses indicated that the 13 Vietnamese isolates were classified into two genotypes, DHAV-1 and DHAV-3. The rate of identity and homology was 91%–100% between the 10 Vietnamese and 26 global strains of DHAV-3, and 92%–100% between 3 Vietnamese and 16 strains of DHAV-1. Between the DHAV-3 and DHAV-1 strains, the divergence reached 30%. At the C-terminal of VP1 for the different strains, a hypervariable region was observed, and notably, six of the Vietnamese DHAV-3 strains in this study showed four consistent differences (at positions T184M, Q200H, K207N, and K214R) within this group that were distinct from all other DHAV-3 strains. Conclusions: This is the first report of molecular characterization of DHAVs in Vietnam. At least two genotypes were identified, DHAV-1 and DHAV-3, with diversified clades within and between genotypes. DHAV-3 seemed to be dominant in Vietnam.
Relationships between low serum vitamin D levels and HBV “a” determinant mutations in chronic hepatitis B patients
Authors: Zhu Huijuan , Liu Xingxiang , Ding Yi , Zhou Hui , Wang Yiying , Zhou Zhiwei , Li Xinxin , Zhang Zengli , Dong Chen
Published: September 2016

Introduction: Vitamin D is significantly associated with virus replication in chronic hepatitis B virus (HBV) infection. However, the relationship between low serum vitamin D levels and HBV “a” determinant mutations remains unknown. Methodology: A total of 133 chronically HBV-infected, treatment-naive patients were randomly selected in the present study. Serum vitamin D levels were measured by using liquid chromatography-mass spectrometry. The HBV “a” determinant was amplified, sequenced, and analyzed by nested polymerase chain reaction (PCR). Results: Among 133 patients, 36, 88, and 9 patients had vitamin D deficiency (25(OH)D < 14 ng/mL), vitamin D insufficiency (25(OH)D ≥ 14 and < 30 ng/mL), and normal vitamin D serum levels ((25(OH)D ≥ 30 ng/mL), respectively. As results showed, 36 [11 genotype B HBVs (HBV/B) and 25 genotype C HBVs (HBV/C)] were isolated from the vitamin D-deficient group, 88 (48 HBV/B and 40 HBV/C) from the vitamin D-insufficient group, and 4 HBV/C strains from the normal serum-vitamin D group. Compared to the HBV/B infected patients with vitamin D insufficiency, higher rates of amino acid mutation within “a” determinant were detected in HBV/B-infected, vitamin D-deficient patients. Moreover, the change frequency of M133 was 27.27% in HBV/B infected patients with vitamin D deficiency, which was significantly higher than those in the vitamin D-insufficient group (p = 0.040). Conclusions: Vitamin D deficiency is significantly associated with genotype B HBV “a” determinant mutations.
Prevalence of cutaneous warts in patients with systemic lupus erythematosus: a systematic review
Authors: Silva Luisa Moreira , Santos Willer Goncalves Dourado , Santiago Mittermayer Barretto
Published: September 2016

The aim of this study was to review and evaluate systematically the scientific evidence on the relationship between systemic lupus erythematosus (SLE) and cutaneous warts (CW) caused by human papillomavirus (HPV) infection. With strict inclusion and exclusion criteria, we extensively searched the PUBMED, BVS (Virtual Health Library), and SCOPUS databases for the studies that evaluated the prevalence of CW in patients with SLE. Secondary references were additionally obtained from the selected articles. Only four articles met the research criteria and showed a higher frequency of CW in SLE patients compared to healthy controls. One of them highlighted about rheumatoid factor (RF) in the sera of patients with SLE and found an inverse correlation between the occurrence of warts and RF autoantibody. Moreover, most of the selected articles showed that the presence of CW did not correlate with the use of immunosuppressive drugs. Therefore, these findings suggest that the prevalence of CW in patients with SLE is probably high due to the defects in immune mechanisms, independently of immunosuppressive drugs.
L’ aed et l’ aemo : approche juridique d’une alternative au placement
Authors: Capelier Flore
Published: September 2016

Cet article rappelle la définition juridique de l’aide éducative à domicile et de l’action éducative en milieu ouvert et insiste sur les principaux enjeux de ces interventions. L’article retient deux approches primordiales liées, d’une part, au respect de l’autorité parentale et à la responsabilité de chacun des acteurs auprès de l’enfant dans ce type de mesure, et, d’autre part, à la manière de concevoir la mesure d’ aed ou d’ aemo comme constituant une étape parmi d’autres du parcours de l’enfant.
L’approche multidimensionnelle systémique en aemo
Authors: Mansuela Loïc
Published: September 2016

Les situations familiales rencontrées dans l’exercice des mesures judiciaires d’action éducative présentent un niveau de complexité important au regard des nombreux enjeux qu’elles impliquent. Les travailleurs sociaux en charge de ces mesures sont confrontés à une somme d’informations et d’éléments de contenus. Quelques outils peuvent aider à constituer une grille de lecture qui permette de prendre en compte tous ces éléments. L’approche multidimensionnelle systémique, enrichie de l’approche narrative des situations et des notions de processus et de «  timing  », permet de co-construire du sens avec les membres des familles concernées.
La fonction palliative de la mesure judiciaire d’investigation éducative
Authors: Macé Aurélie
Published: September 2016

Pour faire face aux délais d’attente en aemo , la pjj se voit confier des mjie qui ne s’inscrivent plus seulement dans l’investigation, mais aussi dans l’accompagnement. Une analyse des conséquences de cette inversion est proposée.
Légendes et confusions juridiques
Authors: Lebrun Pierre-Brice
Published: September 2016

La culture juridique des travailleurs sociaux et médicosociaux repose souvent sur des légendes, des malentendus, des confusions, des bruits qui courent de bouche d’éducateur à oreille d’assistante sociale, des « âneries » qui créent des règles et deviennent des certitudes à force d’être répétées, mais c’est toujours « l’usagé » qui en pâtit, c’est lui dont les droits fondamentaux sont bafoués quand le droit n’est pas respecté.
Part secrète et secret partagé
Authors: Ratier Francis
Published: September 2016

Des lois récentes créent la notion de secret partagé. Elle est ici discutée au regard d’une lecture psychanalytique. Elle témoigne d’une mutation profonde de la société qui organise la tyrannie de la transparence. Les politiques de santé, la société du risque en révèlent les modalités de mise en œuvre. Par ailleurs, le sujet se construit à partir d’une division entre dedans et dehors, un dedans opposé à un dehors et les choses humaines ne prennent place dans le monde que nommées. À l’inverse des nouvelles normes, bon nombre de situations nous confrontent à la nécessité d’accompagner un sujet dans la constitution d’un secret pour les autres mais aussi pour lui-même.
Méthode d’analyse en groupe d’acteurs et souffrances psychosociales sur un quartier de relégation sociale
Authors: Manuello Pascale , Sicot François
Published: September 2016

La souffrance psychosociale est devenue une préoccupation publique à partir des années 1980, d’abord définie dans le cadre de l’émergence des problématiques de l’exclusion. Depuis quelques années, la diffusion de la préoccupation pour ce type de souffrance s’est développée sur un ensemble varié de scènes sociales dont celles des politiques de la ville, de la psychiatrie, du travail, de l’école… À partir d’une recherche action basée sur la méthode d’analyse en groupe d’acteurs et d’un diagnostic réalisé pour la mise en œuvre d’un atelier santé ville sur un territoire de relégation sociale de Toulouse, l’article fait un point sur les problèmes rencontrés par les intervenants sociaux pour prendre en charge des souffrances qui relèvent moins de la psychiatrie que de l’articulation des interventions sociales.
Le journal des années noires revisité
Authors: Rezgui Abdelhakim
Published: September 2016

La double actualité du Journal des années noires , reparu en 2014 chez son éditeur historique alors que vient également d’en être donné, pour la première fois, une traduction anglaise, invite à s’interroger sur le parcours hors norme de ce témoignage sur la France de l’Occupation, devenu canonique. Comment expliquer un tel succès, dans la communauté historienne et au-dehors ? L’histoire du texte, de sa production et de ses réceptions, dont la première, au lendemain de la Libération, permet d’envisager l’œuvre dans le contexte de la « guerre des écrivains » (1940-1953) mais aussi comme un vecteur particulier de la mémoire de la période, de 1947 à nos jours.
Les inégalités ethnoculturelles après les théories de la justice
Authors: Renaut Alain , Brown Étienne , Chartron Marie-Pauline , Lauvau Geoffroy
Published: September 2016

Selon une démarche qui aborde les exigences d’une justice globale en partant des inégalisations les plus extrêmes, cette étude considère les interrogations sur le pluralisme des cultures sous deux angles principaux : celui où les injustices que subissent les sujets dans leurs identités culturelles font intersection avec les inégalités de genre ; celui où l’intersection est prise dans les inégalisations issues du changement climatique. Dans les deux cas, les atteintes au pluralisme des cultures sont interrogées sous leurs formes les plus radicales. L’objectif de cette démarche normative est de penser un interculturalisme raisonné, qui se fonde sur une pratique de la philosophie partant non de principes généraux de justice, mais des données contextuelles des situations injustes, celles des violences massives de genre ou celles des migrations issues de phénomènes d’origine climatique.
Xenía: la amistad-ritualizada de Homero a Heródoto
Authors: Basile Gastón Javier
Published: September 2016

Este artículo examina la construcción lingüística de la amistad-ritualizada a partir del cotejo de los poemas homéricos y de su desarrollo ulterior en las Historias de Heródoto. En primer lugar, se encuadra el fenómeno de la ξενία en las elaboraciones teóricas de la crítica. Luego, se analizan los registros homéricos de la familia léxica organizada en torno al término ξένος, a los fines de precisar las características conjuntas que presenta el lenguaje de la amistad-ritualizada en la epopeya. Por último, se señala el desarrollo particular del esquema conceptual de la ξενία en la narración herodotea. Heródoto emplea una forma nominal abstracta, ξεινίη, inexistente en Homero, como término cuasi-técnico de orden geopolítico y eminentemente secular para designar vínculos inter-aristocráticos de amistad o alianza.
Verbos y argumentos: las combinaciones sintáctico-semánticas del verbo latino cogo
Authors: Torrego M.ª Esperanza
Published: September 2016

En este trabajo se analizan las combinaciones de argumentos posibles con el verbo cogo. Su semántica se organiza en tres ámbitos, ‘reunir(se)’ —cogo 1—; ‘obligar’ —cogo 2—; y ‘recaudar — extorsionar’ —cogo 3—, que dan lugar a varios Marcos Predicativos. Algunas de las combinaciones se explican a partir de los rasgos del verbo (cogo 1 y cogo 2), pero otras parecen colocaciones (‘varear aceitunas’, ‘recaudar dinero’). La sintaxis es la de un verbo transitivo prototípico con un argumento de Dirección (en cogo 1), que se proyecta como un evento infinitivo en el ditransitivo causativo —cogo 2—. La sintaxis de cogo 3 refleja una conceptualización alternativa de la dinámica de fuerzas. La relación conceptual entre los MPs se encuentra en la faceta de ‘coacción’ en el verbo, que se complementa con la de ‘oposición de resistencia’ en el complemento, lo que lo sitúa en un ámbito claro de causatividad.
Un fragmento desatendido de Alceo: el fr. 369 Voigt = 369 Liberman
Authors: Santaniello Carlo
Published: September 2016

Alceo fr. 369 Voigt (= 369 Liberman) ha recibido poca atención. Ateneo de Náucratis lo conservó y Eustacio de Tesalónica sintetizó su contenido. Estos dos escritores suponen que el fr. 369 significa que a veces beber vino suaviza el carácter y a veces lo exacerba. Pero es probable que ni Ateneo ni Eustacio leyeran nunca el poema completo de donde proviene el fragmento. Hay que rechazar tambien las interpretaciones que han propuesto los estudiosos modernos (Page, Liberman), porque no tienen en consideración la alternancia expresada en el paralelo ἄλλοτα μὲν..., ἄλλοτα δ᾽... . Además, hay que rechazar una interpretación literal del fragmento, ya que es absurdo imaginar que hombres del ambiente de Alceo pudiesen beber vino malo o vinagre. El autor del presente artículo sugiere una interpretación alegórica a la luz de la «ley de la mutación eterna» o «ley de la alternancia»: a veces se encuentran días afortunados, a veces días infaustos.
La súplica a Hera en el «Poema de los Hermanos» de Safo
Authors: Velasco López M.ª del Henar
Published: September 2016

La revisión del papel desempeñado por Hera como señora de las tormentas en distintos episodios permite situar la súplica de Safo en el «Poema de los Hermanos» en el contexto mítico-religioso de su tiempo. La doble faceta que revelan las actuaciones de la diosa, soberana y protectora de la unidad familiar, ayuda a comprender mejor el trasfondo del texto y esbozar una hipótesis sobre la razón última del ruego que Safo le dirige.
Predictive Analytics in Operations Management
Authors: Jain Harsh , Pal Amrit , Kumar Manish
Published: September 2016

Operations management is a field of management which emphasizes on managing the day to day operations of business organizations. These organizations possess a huge amount of data which needs to be analysed for proper functioning of business. This large amount of data keeps some useful information hidden inside it, which needs to be uncovered. This information can be retrieved using predictive analytics techniques, which predict the patterns hidden inside the data. This data is heterogeneous, processing of such huge amount of data creates challenges for the existing technologies. MapReduce is very efficient in processing this huge amount of data. In the field of operation management, data needs to be processed efficiently, so it is highly required to process data using parallel computing framework due to its large size. This chapter covers different techniques of predictive analytics based on MapReduce framework which helps in implementing the techniques on a parallel framework.
The Benefits of New Online (Digital) Technologies on Business
Authors: Shaikh Farhan
Published: September 2016

This chapter explores how digital technologies are impacting the businesses – challenging the industry leaders while enabling entrepreneurs to do so. The overall findings have been bucketed under three broad sections – Customer Experience, Process Optimization, and Business Innovation. The Customer Experience section captures the way companies are using the data from digital technologies to enhance the way they interact with the customers. The section on Process Optimization highlights the significant improvements achieved by using digital technologies for existing business processes. Business Innovation captures the transformation power of digital, through new business models, business areas, and data monetization.
Open Collaborative Innovation
Authors: Salazar Maria del Pilar Ramirez , Pérez-Uribe Rafael Ignacio
Published: September 2016

Open innovation is a way that allows the incorporation of external knowledge into a company (Chesbrough, 2003). Open collaborative innovation allows to add an external point of view from different interinstitutional and transdisciplinary entities which look the common goal of provide practical solutions to business challenges that arise in a globalized world (Ramirez, 2016). There are seven components in the Open innovation collaborative model: 1) Innovation challenges, 2) Internal-external knowledge, 3) Paradigm change, 4) Leadership, 5) Interinstitutional and transdisciplinary teams, 6) Storytelling, 7) Creative solutions. It also contains six principles which become thirteen interactive variables: 1) Identity, 2) Agreements, 3) Flexibility, 4) Commitment, 5) Recognition, 6) Trust. This research has identified, among the previously mentioned variables, that in order to be more successful leading projects (taking into consideration the “millennials” generation), it is necessary to strength creativity and communication as essential factors.
Stationary Wavelet Transform Based on De-Noising of Digital Image Correlation in the Investigation on the Impact Response
Authors: Guo Xiang , Li Yu Long , Suo Tao , Tang Zhong Bin , Miao Ying Gang
Published: September 2016

This paper proposes a method for removing image noise form images captured during the impact experiment for the DIC measurement. This paper focuses on estimating the light noise from captured images taken by the deformation during the impact. An image enhanced method based on stationary wavelet transform was employed to improve the stability and accuracy in the DIC measurement. The proposed method was investigated under the impact experiment. The experiment results show that overall the stability and accuracy of the proposed method was improved.
Design and Analysis of Automotive Bumper Covers in Transient Loading Conditions
Authors: Liu Chih Hsing , Huang Ying Chia , Chiu Chen Hua , Lai Yu Cheng , Pai Tzu Yang
Published: September 2016

This paper presents the analysis methods for design of automotive bumper covers. The bumper covers are plastic structures attached to the front and rear ends of an automobile and are expected to absorb energy in a minor collision. One requirement in design of the bumper covers is to minimize the bumper deflection within a limited range under specific loadings at specific locations based on the design guideline. To investigate the stiffness performance under various loading conditions, a numerical model based on the explicit dynamic finite element analysis (FEA) using the commercial FEA solver, LS-DYNA, is developed to analyze the design. The experimental tests are also carried out to verify the numerical model. The thickness of the bumper cover is a design variable which usually varies from 3 to 4 mm depending on locations. To improve the stiffness of the bumper, an optimal design for the bumper under a pre-defined loading condition is identified by using the topology optimization approach, which is an optimal design method to obtain the optimal layout of an initial design domain under specific boundary conditions. The outcome of this study provides an efficient and cost-effective method to predict and improve the design of automotive bumper covers.
Interior Head Impact Analysis of Automotive Instrument Panel for Unrestrained Front Seat Passengers
Authors: Liu Chih Hsing , Lai Yu Cheng , Chiu Chen Hua , Lin Meng Hsien
Published: September 2016

This study presents the numerical and experimental interior head impact analysis of automotive instrument panel according to the United Nations Economic Commission for Europe Regulation 21 (ECE R21). To minimize the possible injury risk for unrestrained front seat passengers due to the interior head impact with the instrument panel, the panel design needs to meet the ECE R21 standard which defines a pendulum-type head form as the impactor. The measured acceleration response of the head form should not exceed 80g continuously for more than 3ms. Motivated by the need to develop a simulation-based technique to evaluate the design of the instrument panel, a numerical model based on the explicit dynamic finite element analysis (FEA) by using the commercial FEA solver, LS-DYNA, is developed. To minimize the experimental cost, a gravity-based impactor with a smaller impact speed is develop as the test apparatus for verification purpose. The simulated results agree well with the experimental data; the average accuracy for the maximum value of impact acceleration at the head form is 95.4%. After the verification, the standard test conditions (with higher impact speed) are performed to evaluate the design. The outcome of this study can provide an efficient and cost-effective method to predict and improve the design of the instrument panel for interior head impact protection.
Numerical Simulation of Behavior of Sand Particles during High-Speed Penetration with Particle Method
Authors: Shimono Ryota , Watanabe Keiko
Published: September 2016

The phenomena that occur during high-speed penetration of a projectile into sand particles are interesting subjects in engineering. The macro-scale research themes are the behavior of the ejected sand particles and the progress of the high-speed projectile, while the micro-scale research themes are the deformation and fragmentation of a single sand particle. Studies of these unique phenomena were conducted using both experiments and numerical simulation. Although accurate simulation of the behavior of sand particles during high-speed penetration is difficult because sand particles have characteristics of both fluids and solids, the reproducibility of the actual phenomena has improved in recent years with the development of particle methods. In our research, we conducted simulations of the phenomena using Smoothed Particle Hydrodynamics (SPH), which is a mesh-free, particle-based method. The results showed the possibility of accurate reproduction during high-speed projectile penetration into sand particles at the macro-scale.
Numerical Simulation on Molten Metal Collision Behavior Using SPH Method Combined with Fractal Analysis on Morphology of Stacking Pattern
Authors: Futakawa Masatoshi , Tsutsui Kihei , Kogawa Hiroyuki , Naoe Takashi
Published: September 2016

The developments of the high power proton accelerators become a worldwide interest to provide various applications, where the targets are demanded to efficiently produce secondary beams and to survive intensive MW class proton beam power supplied by the accelerators. Solid metal targets might be melted by very high heat flux that is caused by the intensive proton beam bombardment. In fact, the incident occurred at J-PARC (Japan Proton Accelerator Research Complex), in which the gold solid target was locally melted to explosively jet molten gold. The molten gold jet collided with a structural beryllium flange plate that has a function of vacuum boundary. Some parts of molten gold were splashed and the other stuck on the flange plate. The relationship between the impact velocity and the morphology of the sticking pattern on the plate was quantitatively evaluated by introducing fractal analysis. It was found that the fractal dimension is correlated with the impact velocity and might be a useful factor to indicate the localized impact force and behavior.
Finite Element Simulation and Experimental Studies on Projectile Perforation of Circular and Rectangular Plates
Authors: Yamada Koki , Moroe Tomoki , Nishida Masahiro , Mizutani Koji , Enomoto Shingo , Matsuda Tomoaki , Bae Kyung Oh , Shin Hyung Seop
Published: September 2016

Experiments and simulations on projectile impact to circular and rectangular plates made of aluminum alloy 2024-T3 were carried out. Ballistic limit and deformation of circular plates and rectangular plates at impact point were examined. The experimental results were compared with the simulation ones which calculated using the materials properties experimentally obtained. The effects of mesh size and fracture strain on both the crack limit velocity and the perforate limit velocity were discussed.
The Texture Effect on the Dynamic Fracture Properties of Magnesium Alloy AZ31B
Authors: Yu Xia , Li Yu Long , Li Tao
Published: September 2016

In this work, Mode I dynamic fracture experiments are conducted on pre-cracked three point bending specimens by using modified split-Hopkinson pressure bar. Two sets of specimens with different initial textures are considered here: one set of the specimens are machined from a hot rolled AZ31B Mg alloy plate with a bigger grain size. The others are treated by four pass of equal channel angular pressing (ECAP) after they are cut from the initial material. They are with the finer grain size. Digital image correlation (DIC) technique is used to determine the strain contours around the crack tip and electron back scatter diffraction (EBSD) is employed to analyze the texture evolution after tests. It is found that the dynamic fracture toughness of finer grain specimen is higher than that of coarse grain specimen. The fracture toughness of both sets of specimens is enhanced by increasing the loading rates. Texture analysis shows the formation of tensile twinning in the ligament ahead of the crack tip in the coarse grain specimen but no sign in fine grain specimen. The brittle features e. g. cleavage planes and twinning lamellas are observed on the fracture surface of coarse grain specimen by scanning electron microscope (SEM). However, the relative ductile features such as micro-voids surrounding by tear ridges present on the fracture surface of fine grain specimen.
Experimental Study of the Effects of Geometry and Strain Rate on Dynamic Behavior of Axial Crushing Honeycomb
Authors: Umeda Tsutomu , Kataoka Kohei , Mimura Koji
Published: September 2016

The axial crushing behavior of some metal honeycombs, of which materials show different characteristics including the strain rate sensitivity with each other, was studied with varying the branch angle at the node of honeycomb, and the effects of geometry and strain rate on that as an energy absorber were discussed. Honeycomb specimens of different branch angles were made by the corrugation technique, and axial crushing tests were carried out under low-speed and impact loading conditions. Then, the effects of the characteristics of stress – strain relation of the material itself, the branch angle and the strain rate on the stress – strain relation of honeycomb structure and the mean buckling stress were examined. The tendency of deterioration in the plateau load or the mean buckling stress due to the irregularity of branch angle was evaluated with considering the influence of boundary conditions by the aid with the numerical simulation. It was also found that the strain rate dependence of metal honeycomb is greatly relaxed as compared with that of the material itself.
Analysis of Plasma Created by High-Speed Impact with Triple Probe
Authors: Umeda Koki , Sakai Takanari , Watanabe Keiko , Kennedy Gregory , Thadhani Naresh
Published: September 2016

The mechanism of destruction of a material by high-speed impact is known to be complex, and it is hard to analyze the inner state of the material during the destruction process. In particular, it is difficult to measure the temperature changes within a material during a high-speed impact. In this study, we propose a new method for estimating this temperature change by measuring the plasma produced at the impact point using a triple probe. A plasma produced by laser ablation was measured to ascertain that the triple probe actually worked. Further, some of the parameters related to the triple probe were varied, and the obtained results were compared, in order to determine the optimal parameters for measuring plasmas. A pulsed Nd-YAG laser with a fundamental wavelength of 1064 nm was employed to produce laser ablation. The laser was irradiated on a thin A2024 plate coated with a black paint. The expanding plasma plume was recorded with a high-speed camera, and the signal from the plasma was measured with the triple probe.
Behaviour of Semisolid Slurry Flows through a Channel
Authors: Simlandi Sudip , Barman Nilkanta , Chattaopadhyay Himadri
Published: September 2016

In case of metal sheet forming of alloys in semisolid state, modelling of the process is very essential to predict flow behaviour, temperature distribution of the alloy etc. towards improvement of the product quality and to reduce manufacturing costs. Accordingly, the present work develops a model to predict the behaviour during metal sheet forming of an Al-alloy (A356) in semisolid state. The semisolid alloy passes through a rectangular channel having small depth and larger width. The alloy in semisolid state is cooled from the top at a controlled rate. In the model, the respective flow field is represented by the momentum conservation equation. The non-Newtonian behaviour of the semisolid slurry is incorporated considering the Herschel–Bulkley model. The agglomeration and de-agglomeration phenomena of the suspended particles under shear are represented using a time dependent structural parameter. The temperature field is predicted considering the transient energy conservation equation, and hence the fraction of solid is continuously updated. The solution considers an apparent viscosity of the semisolid alloy as a function of structural parameter, shear stress and shear rate. The governing equations are finally solved by finite difference method. The work predicts velocity, temperature and liquid fraction distribution of the semisolid slurry.
Determining True Material Constants of Semisolid Slurries from Rotational Rheometer Data
Authors: Alexandrou Andreas N. , Georgiou Georgios C. , Economides Eva Athena , Modigell Michael
Published: September 2016

In this work we revisit the issue of obtaining true material constants for semisolid slurries. Therefore, we consider the circular Couette flow of Herschel-Bulkley fluids. We first show how true constants can be obtained using an iterative procedure from experimental data to theory and vice versa. The validity of the assumption that the rate-of-strain distributions across the gap share a common point is also investigated. It is demonstrated that this is true only for fully-yielded Bingham plastics. In other cases, e.g., for partially-yielded Bingham plastics or fully-yielded Herschel-Bulkley materials, the common point for the fully-yielded Bingham case provides a good approximation for determining the material constants only if the gap is sufficiently small. It can thus be used to simplify the iterative procedure in determining the material constants.
Liquid-Solid Microextrusion of Aluminum Alloy
Authors: Zhou Ji Ming , Li Zhen , Qi Le Hua , Wang Xin Kang
Published: September 2016

Liquid-solid microextrusion is one type of microplastic forming processes at elevated temperature and can be used in the forming of pins, screws, shafts, and gears in micro-scale. Microextrusion setup operated by use of ball screw was designed and fabricated by authors. Microshaft of diameter 1 mm was extruded in the liquid-solid state at different forming temperature from Al-Mg alloy ER5356 billet of 4 mm in diameter. Heating temperature in the furnace for billet were set 650, 700, 750, and 800 degree C which was corresponding to the forming temperature range from 475 to 631 degree C because of temperature drop during transfer from furnace to mold. Forming load ranged from 4kN to 8kN. Microstructural observation shows that the grain size was reduced greatly compared to the original billet material. Microindention hardness shows that the extruded pin was strengthened which caused by small grain size.
Controlling and Minimizing Blistering during T6 Heat Treating of Semi-Solid Castings
Authors: Lu Hong Xing , He You Feng , Midson Stephen , Li Da Quan , Zhu Qiang
Published: September 2016

Surface blistering during T6 heat treating is an artifact that is essentially unique to high pressure casting processes such as semi-solid casting and die casting. It is believed that the blistering originates from subsurface defects present in the castings. When the castings are exposed to elevated temperatures during solution heat treatment, the strength of the aluminum is reduced, and the defects expand to deform the surfaces of the castings. There are three potential sources for the subsurface defects - entrapped air, die lubricant or shot sleeve lubricant.This paper will report on a study to determine the origin of the defects present in the castings that produce the blisters. Along with attempting to separate the influence of air and the two types of lubricants on blister formation, the study will also examine the impact of a number of process parameters on blistering.
Experimental Investigations on the Formation of Rosettes during Shear
Authors: Harboe Siri , Sothyratnam Vijenthan , Modigell Michael , Pola Annalisa
Published: September 2016

In this work, the effect of stirring conditions on agglomeration and coalescence-coarsening in isothermal, globulitic, semisolid AlCu10%wt was investigated. It is shown that for the investigated system, a shear rate regime exists which promotes crystallographic alignment of the agglomerated grains, leading to a rapid coalescence process, thereby the formation of rosettes. It is also experimentally validated that for lower shear rates, the size and porosity of aggregates are increased compared to that at higher level of shear.
The Interface Morphology of Thixo-Joined Dissimilar Steels
Authors: Mohammed M.N. , Omar Mohd Zaidi , Alhawari Khaled S. , Abdelgnei Mnel A. , Saud Safaa Najah
Published: September 2016

In many circumstances, a high quality joint of dissimilar metals can be hardly achieved by conventional welding process. In this study, a new process of joining semi-solid AISI D2 tool steel and AISI 304 stainless steel using a partial remelting method is proposed. The differences of two dissimilar steels at the test temperature on microstructural developments across the interface joint area were investigated. After Thixo-Joining, Interfacial microstructures were examined by optical microscope and scanning electron microscope (SEM) equipped with EDS (energy dispersive spectroscopy) in order to verify the interface welded area during the joining process while X-ray phase analysis was performed to identify the phase evolution and the type of carbides. The experimental results showed that at 1300°C a full penetration welded joint can also be clearly seen, whereby the base metal (D2 tool steel) is connected to the insert metal (304 stainless steel) along the bonding boundary to achieve what appears to be a perfect joining at the interfaces of both metals.
Development and Achievements of SSM Processes for High Performance Components
Authors: Rosso Mario , Peter Ildiko , Gattelli Ivano
Published: September 2016

During the last decades under the enthusiastic and competent guidance of Mr Chiarmetta SSM processes attained in Italy at Stampal Spa (Torino) an unquestionable high level of industrial development with the production of large numbers of high performance automotive parts, like variety of suspension support, engine suspension mounts, steering knuckle, front suspension wheel, arm and rear axle. Among the most highlighted findings SSM processes demonstrated their capability to reduce the existing gap between casting and forging, moreover during such a processes there are the opportunity to better control the defect level.Purpose of this paper is to highlight the research work and the SSM industrial production attained and developed by Mr G.L. Chiarmetta, as well as to give an overview concerning some alternative methods for the production of enhanced performance light alloys components for critical industrial applications and to present an analysis of a new rheocasting process suitable for the manufacturing of high performance industrial components.
Effects of Natural Ageing on T6 Heat Treated Rheocasts of 319S Aluminum Alloy
Authors: Du Kang , Zhu Qiang , Li Da Quan
Published: September 2016

T6 heat treatment is an effective method to improve the comprehensive properties of Al-Si-Cu-Mg series aluminium alloys. Solution treatment temperature and time, quench process and media, as well as artificial ageing temperature and time are the key factors to determine mechanical properties. Besides these factors, natural ageing, i.e. the holding time between quenching and the starting of artificial treatment at ambient temperature was observed to be significant affect mechanical properties of the aluminium alloys. This effect on semi solid processed aluminium alloys was lack of investigations as the semi solid process produces T6 treatable and weldable components. The present paper focuses on the change regularity of hardness and precipitate behaviour of semi-solid 319S aluminium alloy under different natural ageing (NA) treatment additional to standard T6. Density and morphology of hardening precipitates are analysed using TEM, and the influence mechanism of NA during T6 heat treatment will be discussed. The results show that NA has a positive influence on mechanical properties of the rheo-cast 319S alloy.
Macro-Observation of the Interface of the Al-22%Si-Cu/Al-7%Si-MG Bi-Metal Parts Fabricated by Thixoforging
Authors: Yang Zhao , Wang Guang Xu , Xu Xue Xuan , He Xiao Long , Lu Jian Ning
Published: September 2016

Thixo-forging has been proved to be able to fabricate bi-metal parts with a complex outline and a relatively regular interface economically. These products have potential applications on high volume stability radiators, brakes, and pistons. However, it is very difficult to evaluate the curved interfaces by micro observations. In this work, Al-22%Si-Cu/Al-7%Si-Mg bi-metal parts were fabricated by thixo-forging; state of the interfaces of the bi-metal parts was investigated by X-ray flaw detector observations and tensile test; optical microscope (OM) observation and scan electron microscope (SEM) observation were applied to assist the analysis. The results show that the metallurgical bonding of the interfaces is of good quality. No large scale flaw was found on the interface in X-ray flaw detector observation. It was found that higher forging pressure decreased the size of the crack on the interface and in the matrix. However, higher forging pressure can slightly improve tensile strength. Large ratio of fresh interface relates to original interface resulted in a slightly better tensile strength. Without heat-treatment, the bi-metal forgings have an average tensile strength of 106 MPa. T6 heat treatment blunted the blades of the plate like crack and nodulized the defects, T6 heat treatment also decreased the size of the Si particles. As a result, the average tensile strength of the bi-metal forgings increased to 200 MPa.