bluuebunny/crossref_metadata_2025 huggingface dataset:
La investigación criminológica en España
Authors: Stangeland Per
Published: April 2021

50 números del Boletín Criminológico

Tras seis años y medio de activida ininterrumpida, esta modesta publicación alcanza el medio centenar de números Lo que empezó siendo un medio para difundir resúmenes de los trabajos de investigación que tenían lugar en el seno del instituto Andaluz Universitario de Criminología ha ido abriendo sus páginas a aportaciones de toda la nación e incluso extranjeras, y se ha consolidado como uno de los medios españoles más ágiles y eficaces en la puesta en conocimiento de toda la comunidad criminológica de los diferentes proyectos y actividades de investigación en curso o concluidos. Buena prueba del éxito de su trayectoria es que haya servido de modelo para otras publicaciones aparecidas con posterioridad, que han enriquecido el panorama criminológico español. Como Director de la Sección de Málaga del IAIC no quisiera dejar pasar esta efemérides sin manifestar mi agradecimiento a su ideador, Per Stangeland, y a todos los que con él, desde la coordinación y últimamente desde la dirección, han garantizado su puntual aparición estos años, así como a todos los autores que nos han honrado con sus colaboraciones.

Nos ha parecido procedente que este número tan especial sirviera para realizar una crítica reflexión sobre la evolución de la investigación en Criminología en España en los últimos tiempos.
Instituto de Criminología de Málaga: 10 años de Docencia
Authors: Serrano García Ángel
Published: April 2021

Recientemente el Consejo de universidades ha remitido al Ministerio de Educación una propuesta de Título oficial de Criminología, estructurado como una licenciatura de segundo ciclo. Se culminan así los accidentados esfuerzos del conjunto de Institutos de Criminología y Cursos de especialización de las diferentes universidades que, en colaboración con la Federación de asociaciones de criminólogos, hicieron una propuesta de directrices la cual, aunque con reformas de alguna importancia, ha sido finalmente asumida por el Consejo de universidades. De esta forma se va a dar carácter oficial a unos estudios con una notable tradición y consolidación en nuestro país, pero que nunca habían gozado de reconocimiento oficial.

Su existencia desde hace años como enseñanzas propias de las respectivas universidades, sin embargo, permite disponer de datos abundantes sobre las necesidades sociales a cubrir por tales estudios, sectores profesionales en ellos interesados y perfil de la demanda. El Instituto andaluz interuniversitario de Criminologia viene impartiendo estas enseñanzas desde hace doce años, de manera homogénea en cinco universidades, y constituye el Instituto con mayor volumen de alumnado, profesorado y actividades en toda la nación. Consciente de ello, la sección de Málaga del Instituto ha creido conveniente poner a disposición del público una serie de datos significativos sobre la actual realidad de los estudios de Criminología en Andalucía, con la esperanza de que puedan ser útilies a la hora de estructurar e implantar estos estudios en el Estado. Con ello, por lo demás, los responsables de este Boletín continúan una práctica que ya tuvo un precedente en el Boletín número 30.
Víctimas de la actividad criminal
Authors: Valenzuela Ratia Diego
Published: April 2021

La pretensión de este trabajo es mostrar las entrañas del proceso de elaboración de las estadísticas oficiales de laS fuerzas y Cuerpos de seguridad del estado ( Policí a Nacional, Guardia Civil y Policía Autónoma Vasca). Es de alabar la preocupación que la Secretaría General Técnica del Ministerio del Interior ha mostrado por su mejora y los progresos llevados a cabo para adaptar y ofrecer unas estadísticas cada vez mas fiables y con mas información.

En todo caso, la utilidad que los datos policiales tiene para el científico exige no sólo que el número de variables objeto de atención se amplie, sino que se permita también un acceso directo a los datos por parte de los investigadores. Es sentir de los criminólogos españoles el pesar por no poder acceder a ellos más que a través de los resultados ofrecidos por la institución que los recoge. El acceso directo a los datos policiales y judiciales por parte de los estudiosos es una práctica habitual en otros paises de nuestro entorno, en los que los conocimientos aportados por las investigaciones criminológicas, siempre en progreso, constituyen, entre otras cosas, la base de las políticas de intervención y prevención. No obstante, estamos ante uno de los mejores instrumentos cuantitativos existentes en España para realizar estudios criminologicos, siendo además plausible la actualidad con la que son dados a conocer.
Juicios rápidos e inmediatos
Authors: Bayo Delgado Joaquín
Published: April 2021

La generalización de los llamados juicios rápidos está suscitando un justificado interés entre los opedadores jurídicos y el público en genreral. Esta modalidad procesal, aunque con un ámbito más limitado, tiene ya desde hace más de 10 años unas previsiones legales que la posibilitan.

Algunas ciudades entre las que destaca Barcelona, supieron en su momento desarrollar esas previsiones y tienen ya una notable experiencia en este tipo de juicios. Nuestra revista ha solicitado al Juez decano de Barcelona, Joaquín Bayo Delgado, que haga un análisis de la reforma procesal desde la experiencia que ha acumulado en el Decanato.
Urbanismo, corrupción y delincuencia organizada: Conclusiones y recomendaciones
Authors: Diez Ripollés José Luis , Gómez-Cespedes Alejandra , Prieto del Pino Ana María , Stangeland Per , Vera Jurado Diego
Published: April 2021

Urbanismo, corrupción y delincuencia organizada: Conclusiones y recomendaciones
Justicia juvenil en Andalucía (II): elección de medidas a imponer, y contenido educativo
Authors: Pérez Jiménez Fátima , Rivas Moya Teresa
Published: April 2021

Justicia juvenil en Andalucía (II): elección de medidas a imponer, y contenido educativo
La coordinación de servicios para víctimas de los delitos (Una experiencia innovadora en Denver, Colorado)
Authors: Soler Ana C. , Barberet Rosemary
Published: April 2021

En junio de 2004, la embajada de los Estados Unidos de América en España, previa petición de la Dra. Rosemary Barberet de la Universidad Carlos III de Madrid, financió la visita a España de Ana Soler, directora del "Victim Services Network" de Denver, Colorado. Esta visita resultó en la organización de tres conferencias (en Madrid, Barcelona y Valencia) Copatrocinada por distintas entidades preocupadas por la justicia y las víctimas: el Observatorio de justicia y empresa del Instituto de Empresa en Madrid, el Grupo de Estudios Avanzados en Violencia de la Universidad de Barcelona, el Departamento de Justicia de la Generalitat de Catalunya y la Consejería de Justicia y Administraciones Públicas de la Generalitat Valenciana. Este número del Boletín Criminológico ofrece un resumen de la conferencia impartida por Ana Soler, complementada en su inicio con referencias a la situación española.
El acoso escolar en Málaga capital
Authors: Enriquez Vázquez David , Calvente Montero María Jesús
Published: April 2021

Durante los últimos años ha ido creciendo en nuestro país la preocupación social por los actos de violencia escolar, habiendo alcanzado en algunos casos una gravedad tan extraordinaria que les han hecho tristemente merecedores de un amplio protagonismo informativo. Se piensa en general que el acoso escolar se refiere exclusivamente a algo físico y externo, tales como peleas y agresiones entre alumnos. Sin embargo, hay multitud de actitudes de acoso verbal y social que dan lugar al llamado, según los expertos, acoso psicológico, que tiene similares efectos demoledores. El presente estudio pretende conocer la incidencia real de estos hechos en los institutos de enseñanza obligatoria en Málaga capital.
Evaluación de las medidas en medio abierto del plan de justicia juvenil de la comunidad autónoma del País Vasco
Authors: San Juan César , Ocáriz Estefanía , De la Cuesta José Luis
Published: April 2021

La justicia juvenil está acaparando gran parte de la atención de los investigadores de nuestro país en los últimos años. Las recientes reformas legislativas llevadas a cabo unido a la trascendencia que se le otorga a la prevención de la delincuencia juvenil, hace que nos encontremos ante un tema al que cualquier sociedad, preocupada por el aumento de la delincuencia, debe dar máximo protagonismo. El trabajo que se presenta ha sido elaborado por investigadores del Instituto Vasco de Criminología y ha sido financiado por el Departamento de Ejecución Penal del Gobierno Vasco. Poco a poco parece estar adquiriendo mayor importancia la evaluación de normas, programas y medidas, siendo este último el caso del presente estudio.
La medición estadística de las pautas espacio-temporales del delito
Authors: Summers Lucía
Published: April 2021

La aplicación de técnicas epidemiológicas en el estudio de determinados delitos, especialmente aquellos contra la propiedad, ha demostrado que éstos se aglomeran espaciotemporalmente. Es decir, una vez que un determinado delito tiene lugar es más probable que otro ocurra a poca distancia y poco después del inicial. La identificación de estas pautas espaciotemporales nos permite trazar mapas predictivos, muy útiles para contribuir a la prevención del delito y a la detección y detención de los delincuentes. Este trabajo metodológico, realizado por una profesora de UCL Hill Dando Institute of Crime Science de Londres, describe dos de las técnicas epidemiológicas más utilizadas en el estudio de las pautas espaciotemporales del delito: la tabla de contingencia de Knox y la simulación de Monte Carlo.
Individuos, sociedades y oportunidades en la explicación y prevención del delito: modelo del triple riesgo delictivo (TRD) (Primera parte)
Authors: Redondo Illescas Santiago
Published: April 2021

Es una satisfacción para nuestra revista el poder presentar en este número y en el siguiente una sucinta y clara exposición, llevada a cabo por su propio autor, del Modelo del triple riesgo delictivo -TRD- relativo a la explicación y prevención de la delincuencia. La propuesta aludida constituye un sobresaliente ejemplo de sistematización y operacionalización del conocimiento criminológico contemporáneo. Entre sus virtudes cabe mencionar su capacidad para integrar en un único modelo teórico y práctico las muy diversas contribuciones, empíricamente acreditadas, del pensamiento criminológico contemporáneo. A su vez, la descomposición de la probabilidad de conducta antisocial en tres dimensiones continuas de mayor a menor riesgo, mutuamente entrelazadas, potencia el desarrollo de estrategias de prevención más eficaces. Por último, la convicción de que una de las vías más eficientes para prevenir la delincuencia sea la incidencia sobre los factores sociales o dimensión B, tanto en la intervención personal como en la social, constituye otro de los acervos de este modelo, que le permite enlazar con una persistente corriente criminológica.
Team Category and Gender Differences of Resilience among High-Level Volleyball Players
Authors: Patsiaouras Asterios
Published: April 2021

SUMMARY

The objective of this study was to investigate the difference in resilience level of high-level volleyball players. Ninety-eight volleyball players (National team players U21, Pre-League and Second Division A2 teams’ players) participated to the study (fifty females and forty-eight males). The Self Evaluation Resilience test was used for the study. The data were analyzed with SPSS 21.0 using t-test for independent samples, and one-way ANOVA with post hoc Bonferroni adjustment test. Results showed statistically significant differences between the males and females volleyball players in variables ‘‘orientation on solution and aims’’’ and ‘‘self-efficacy’’. Additionally, statistically significant differences were observed in the variables ‘‘orientation on solution and aims’’, ‘‘healthy lifestyle’’ and ‘‘self-efficacy’’ according to players team category. Future research should investigate if the behavior of the coach in the team, or the team category affects the resilience level of the players
Uji Antioksidan Ekstrak Daun Tanaman Leunca (Solanum nigrum L.)
Authors: Fauziah Affrina , Sudirga Sang Ketut , Parwanayoni Ni Made Susun
Published: April 2021

Tanaman leunca (Solanum nigrum L.) merupakan salah satu tanaman yang sering digunakan sebagai bahan pangan bagi masyarakat Indonesia. Daun tanaman leunca banyak dimanfaatkan untuk obat-obatan herbal. Penelitian ini bertujuan untuk mengetahui kandungan fitokimia dan aktivitas antioksidan dari ekstrak daun leunca (Solanum nigrum L.). Penelitian dilakukan di Laboratorium Analitik Universitas Udayana, Laboratorium Organik Program Studi Kimia Universitas Udayana dan Laboratorium Fakultas Teknologi Pertaian Universitas Udayana. Uji fitokimia dilakukan untuk mengetahui keberadaan senyawa alkaloid, steroid/triterpenoid, flavonoid, fenol dan tanin. Aktivitas antioksidan ekstrak daun leunca (Solanum nigrum Linn) diuji dengan metode DPPH (1-1-difenil-2-pikrilhidrazil), dengan 5 konsentrasi yang berbeda dan teridiri dari 4 ulangan. Ekstrak daun leunca positif mengandung senyawa alkaloid, steroid/triterpenoid, flavonoid, fenol dan tanin. Hasil penelitian menunjukkan bahwa ekstrak daun leunca kering dan ekstrak daun leunca segar memiliki aktivitas antioksidan yang berbeda. Ekstrak daun leunca kering tergolong antioksidan kuat dengan nilai aktivitas antioksidan 64,40 %, nilai IC50 sebesar 95,12 ppm dan ekstrak daun leunca segar tergolong antioksidan lemah dengan nilai aktivitas antioksidan sebesar 16,83%, nilai IC50 sebesar 243,66 ppm.

 

Kata Kunci : Solanum nigrum L., herbal, fitokimia, antioksidan, DPPH.
Prevalence Of Leucocytozoonosis And Plasmodiosis In Duck (Anas platyrhynchos) That Are Maintained In The Household Scale
Authors: Kartika Sari Kadek Indah , Sudatri Ni Wayan , Suartini Ni Made
Published: April 2021

Leucocytozoon and Plasmodium are blood parasitic protozoa that can be found in poultry blood including ducks. These protozoa can cause Leucocytozoonosis and Plasmodiosis in poultry. Spread of the disease through different biological vectors. Similium sp. and Culicoides arakawae as vectors of Leucocytozoonosis and vectors of Plasmodiosis are Culex sp., Culiseta sp., and Aedes sp. This study aims to determine the prevalence of Leucocytozoonosis and Plasmodiosis in ducks that are maintained on a household scale. Ducks are taken from four locations (breeders on a household scale) in Besan Village. In each location, 5 ducks were taken so that the total number of ducks used was 20. This research used purposive sampling method. Samples of duck blood were made as blood smear preparations and stained with 10% Giemsa stain solution then observed under a microscope. The parameters observed were the percentage of blood samples infected with Leucocytozoon and Plasmodium and hematological parameters (total leukocyte count, total erythrocyte count, hemoglobin level, and PCV value). The results showed that Leucocytozoon and Plasmodium were not found in duck blood cells. The prevalence of Leucocytozoonosis and Plasmodiosis in ducks was 0%. The average value of duck blood profile through One Way Anova statistical analysis showed no significant difference between ducks from each sampling location (p> 0.05) and the value of duck blood profile for all samples was within the normal range.
El laboratorio de la educación: Francisco J. Múgica en Tabasco y Michoacán
Authors: Chávez Jiménez Daniar , Ramírez Sánchez Rubén Darío
Published: April 2021

Resumen: En este artículo se analizan las transformaciones que sufrió el sistema educativo del estado de Tabasco durante el gobierno del general Francisco J. Múgica (1915-1916). Se destaca la importancia de las reformas impulsadas en materia de reestructuración administrativa, en infraestructura y pedagógica, esta última desde el punto de vista de la educación racionalista, que culminaría con la puesta en marcha de la República escolar, a través de la cual se buscó diseminar los valores revolucionarios, fomentar la autonomía municipal e impulsar la educación rural. También se abordan algunos cambios educativos que durante su breve estancia como gobernador del estado de Michoacán, a principio de la década de los años veinte, llevó a cabo en el estado, entre ellos la restructuración administrativa de la universidad de la entidad y las normales rurales. Palabras clave: Educación, República escolar, Constitución, Francisco J. Múgica.
Los orígenes de la "Verdad Histórica": los primeros informes sobre la desaparición forzada de personas en México.
Authors: Gamiño Muñoz Rodolfo
Published: April 2021

El presente artículo analiza los dos primeros Informes de Investigación que sobre la desaparición forzada de personas se hicieron en México. Ambos informes abordan el caso de la movilización armada rural en el Estado de Guerrero a principios de la década de los setenta.El primer Informe fue realizado por el entonces Procurador de la República Oscar Flores González, en el año de 1979 y, el segundo, es el Informe de Investigación sobre presuntos desaparecidos en el Estado de Guerrero durante 1971-1974, conocido también como Informe Carpizo, elaborado en 1990.La revisión de ambos informes devela cómo el estado mexicano ha enfrentado la desaparición forzada como un fenómeno perene, cuáles ha sido el uso que ha dado a las instituciones del Estado y las técnicas legales y burocráticas para dar salidas a este delito continuado. Ambos Informe resultan ser fundamentales para realizar un análisis de largo aliento para lograr establecer las rupturas y continuidades en los patrones de la desaparición forzada de personas y, sobre todo, las salidas institucionales, políticas y jurídicas que el Estado mexicano ha dado a este fenómeno, el cual se expuso, nuevamente, como una “verdad histórica” en el caso de la desaparición forzada de los jóvenes de la Normal Rural de Ayotzinapa en el año 2014.
Innovación hidráulica y elecciones técnicas en los Altos de Morelos, México
Authors: Villagómez-Reséndiz Radamés
Published: April 2021

El presente trabajo constituye una crítica al cuestionamiento antropológico sobre la noción de innovación que subyace a la transferencia tecnológica en los Altos de Morelos. A partir del análisis de literatura especializada apoyada en trabajo etnográfico, argumentamos que si los sistemas hidráulicos, en tanto conocimientos locales, se han modificado históricamente independientemente de los cambios impulsados por las tecnologías apropiadas, y si tales modificaciones implican una remembranza de la tradición y una proyección hacia el futuro (i.e. memoria en expansión), entonces el cambio cultural relativo a la tecnología hidráulica puede concebirse en términos de innovación a partir del concepto de elecciones técnicas tal como ha sido empleado en la antropología de la tecnología.
Aproximación etnohistórica sobre el uso y semidomesticación de la xuta (Jatropha curcas L.) en la Nueva España
Authors: Figueroa Saavedra Miguel , Montero Liliana , Sánchez Sánchez Odilón
Published: April 2021

Este trabajo estudia desde un acercamiento etnohistórico el uso humano de la Jatropha curcas entre los siglos XVI y XIX en Nueva España. El análisis crítico y directo de las fuentes de información pertinente permitió corroborar que la especie ha sido aprovechada por diferentes grupos culturales durante este periodo. Si bien estos usos (medicinales, alimenticios, artesanales, etc.) difieren de algunos actuales, muestran un continuo cultural y dejan ver su preponderancia en el proceso de domesticación de esta planta en México.
4. Problematic Overlap of Algonquin Park Eco-Tourism and Most Suitable Habitat for the Protection of Black Bear Biodiversity
Authors: Barsony Celeste , Bishop Elise , Mulveney Jill , Patel Aasif
Published: April 2021

The purpose of our study is to identify problems arising or that have arisen within the biodiversity of the Algonquin to Adirondacks (A2A) region caused by ecotourism. Our full study will include examining three different species preferred habitat ranges and the possible anthropocentric impacts imposed on these habitats and biodiversity. Specifically, we look at the black bear (Ursus americanus) within the region of the Highway 60 corridor in Algonquin Park during the busiest months of the park (spring and summer).  The main methodology for this study is using Geographic Information Systems (GIS) conduct a suitability analysis for each species, and then identify areas of overlap with Algonquin Park Eco-Tourism. By studying the impacts of Eco-Tourism on the bear populations, and their most suitable habitat regions, we hypothesize that ecotourism will have dangerous impacts on their habitat ranges and biodiversity potentials. To correct this, we will suggest specific times in the season to avoid using the said Eco-Tourism campsites, portage routes, trails and outpost cabins.
11. The Gender Wage Gap of Recent University Graduates
Authors: Thornton Annabel
Published: April 2021

The purpose of this research was to question whether the behavioural tendencies of men and women could help explain the gender wage gap of recent university graduates. It was conducted after discovering that a 2013 study found that even once accounting for observable characteristics such as age, experience, industry, occupation, and field of study, female graduates were still earning 6-14% less than their male counterparts. Using the willingness of a graduate to gamble a current job offer for a potentially better job offer in the future as a proxy for risk, this research investigates the impact risk preferences have on the gender wage gap. More specifically, it attempts to calculate how much of the observed wage gap can be attributed to the greater risk aversion of women. 

Our data was from the National Longitudinal Survey of Youth 1997. Using a McCall Job Search model and an MLE, we found that women take approximately 4.5 fewer weeks to accept a job, accept significantly lower starting salaries, and are systematically offered lower salaries than their male counterparts. Furthermore, we found that women have an Arrow-Pratt coefficient almost 1.25 times that of men. These results suggest that women are more willing to accept lower wage positions offered to them today because they are less willing to gamble that a higher wage position will come along tomorrow. Moreover, they propose that this female unwillingness to gamble can explain up to a quarter of the difference in the wages accepted by men and women.
14. Radiation Therapy Planning for Skin Cancer: Using 3D Surface Scanning to Localize Tumour
Authors: Ilina Anna
Published: April 2021

Orthovoltage radiation therapy (ORT) is a non‑invasive treatment often used for patients with skin cancer, which is characterized by shallow tumours visible at the surface of the skin. Currently there is no commercially available treatment planning system for ORT. The first step of treatment planning is localizing the tumour in a computed tomography (CT) scan of the patient. We propose using 3D surface scanning to obtain a coloured and textured image of the patient, from which the tumour can be identified. The contour of the tumour can then be overlaid onto the CT image, for planning delivery of radiation therapy. This process was demonstrated using a male mannequin model, with a red sticker on the nose representing a skin tumour. A coloured and textured image of the face was obtained using a handheld 3D surface scanner [Figure 1]. The surface scan was aligned to a CT image of the mannequin head using a two‑step registration process, with a resulting error of 0.25mm. The tumour could then be easily segmented from the coloured surface scan by following the outline of the lesion. The tumour contour was extended in depth to 1cm, to encompass subdermal cancerous tissue in the treatment volume, and saved with the CT image for treatment planning [Figure 2]. This workflow is the first step to an open-source treatment planning system for ORT, which will allow physicians to deliver more precise treatment using ORT. This project was done in collaboration with the Kingston General Hospital.
Sitting through life? Psychosocial Antecedents of Sedentary Behaviour in a Post-Secondary Setting
Authors: Calderhead Sophie
Published: April 2021

Currently, there is a paucity of research on the psychosocial antecedents of sedentary behaviour (SB) in a post-secondary setting. Theory of Planned Behaviour (TPB) constructs may influence sedentary behaviour amongst students. Further, normative messages may be one tool for altering perceptions of sedentary behaviour. However, the effect of descriptive norm messages on sedentary behaviour is currently unknown. The primary purpose of this study is to examine students’ perceptions of sedentary behaviour; the secondary purpose is to investigate whether the receipt of a normative message is an efficacious tool for reducing students’ sedentary behaviour. Post-secondary students will complete an online questionnaire and will randomly receive an injunctive norm, descriptive norm, or control sedentary behaviour message. The questionnaire will measure demographics, TPB constructs, and self-reported SB. One week later, they will complete the same questionnaire. Multiple regression and ANOVAs will be used to address the two study purposes, respectively. Results may inform future interventions aimed at decreasing students’ sedentary behaviour levels.
Comparison of different sensor technologies to monitor a forging process
Authors: Durand Camille , Freund Ludovic , Baudouin Cyrille , Bigot Régis , Guérin Jean-Dominique
Published: April 2021

Nowadays, numerical simulations are more and more used in forging industry, and their predictability is validated through a comparison with experiments. But sometimes simulations and experiments provide significantly different results. And quite often, the models implemented in simulations are taken for responsible of this divergence with experimental results. But results experimentally obtained can also be discussed. Depending on the operatory conditions, and the type of sensor used, measured results can be different. Moreover, integrating sensors is not an easy task for forging processes, as sensors could be exposed to harsh environment with high speeds, high forces, high temperatures, radiations, … In this paper data for displacement and force measured by different sensors are compared. Advantages of different sensor technology are discussed in the case of hot forging processes performed with energy piloted machines.
Fracture Toughness and Tribological Properties of Cemented Carbides Machined by Sinking Electrical Discharge Machining
Authors: Petersen Timm , Küpper Ugur , Herrig Tim , Klink Andreas , Bergs Thomas
Published: April 2021

The quality of a forming process highly depends on the pressure applied to the workpiece. Consequently, the demand for higher workpiece qualities results in a demand for tools that can withstand high compressive stresses. Moreover, the tendency of using materials like high-strength steels as workpiece material, urges the need for tool materials that can withstand high compressive stresses and are resistant to wear. A class of materials that offer a combination of hardness or wear resistance and ductility are cemented carbides. However, these properties hamper their machining with conventional cutting technologies. Due to its electro-thermal working principle, Electrical Discharge Machining (EDM) is able to machine materials independently from their mechanical properties. On the other hand, the removal process is accompanied by thermal stresses, which can cause residual stresses and micro cracks near the machined surface. Due to their pre-existing stresses from the sintering process, cemented carbides are especially susceptible for these kind of damages. It is therefore necessary to identify the impact of EDM on the material. Different machining strategies are tested with two different types of cemented carbides and examined regarding their fracture toughness. The crack surfaces resulting from the three point bending test are microscopically inspected regarding failure initiation. Additionally pin-on-disc tests are conducted to determine the influence of the EDM strategies on the tribological properties of the machined cemented carbides.
Effect of powder size and processing parameters on surface, density and mechanical properties of 316L elaborated by Laser Powder Bed Fusion
Authors: Ziri Sabrine , Hor Anis , Mabru Catherine
Published: April 2021

Despite the attractive capabilities of additive manufacturing (AM) technology, the industrialization of these processes remains very low. This is attributed to the complexes physical phenomena involved in the AM process and the layered structure of the produced parts. Intense research work is still needed for the prediction and optimization of AM parts mechanical properties. In this study, the influence of particle size distribution (PSD) of stainless steel 316L (SS 316L) powders on AM parts properties was investigated. Four PSD were used to produce test parts and compare the resulting porosity, surface roughness and macro-hardness. The SS 316L specimens were fabricated by Laser Powder Bed Fusion process (LPBF) on a SLM 125HL machine using variations in laser power and scan velocity. Computed scan tomography (CT) was used to characterize the defects. Lack of fusion and keyhole defects were detected. Defects were detected even in nearly dense parts. The powder size distribution was found to affect the porosity. Results from CT tests were used to identify the minimum achievable porosities for each powder, through the appropriate selection of process parameters. The macro-hardness and surface roughness were found to vary with the powder properties.
Development of an experimental approach to study preforming mesoscopic defects of woven fabrics
Authors: Shanwan Anwar , Allaoui Samir , Gillibert Jean , Hivet Gilles
Published: April 2021

Composite materials can be produced by several technologies, such as Liquid Composite Manufacturing (LCM). In this technology, a fabric can be formed by highly double curved punch geometries. During its forming, the fabric is submitted to several deformations and mechanical stresses, like biaxial tensile stress, shear, bending, compaction and friction. The cumulative effect of these stresses leads to the appearance of different types of defects such as wrinkles, buckles, sliding, etc. These defects may have a significant influence on the mechanical properties of the final composite materials. In order to understand the forming mechanisms of these defects, as well as their effect on the behavior of composite materials, an experimental machine was designed and built. The aim of this machine is to generate different types of defects with controlled and adjusted amplitudes (calibrated defects), in samples of a fabric. These samples are then used to manufacture composite samples with calibrated defects, by an LCM process. The defected composite samples are then tested and compared with composite samples without defects. The obtained results have identified the experimental parameters corresponding to the appearance of different types of defects.
Relationship Between Crystallization, Mechanical and Gas Barrier Properties of Poly(ethylene furanoate) (PEF) in Multinanolayered PLA-PEF and PET-PEF Films
Authors: Guinault Alain , Messin Tiphaine , Anderer Gilbert , Krawielitzki Stefan , Sollogoub Cyrille , Roland Sebastien , Grandmontagne Anne , Dole Patrice , Julien Jean-Mario , Loriot Catherine , Vincelot Thierry
Published: April 2021

Food packaging films must be reinvented in order to answer the new demanding ecological requirements. Biobased and/or biodegradable polymers appear as an interesting alternative to reduce petroleum dependence and carbon dioxide emissions. Poly(ethylene furanoate) (PEF) appears today as a new promising biopolymer thanks to its good gas barrier and mechanical properties, despite its high price that could limit its industrial applications. Its combination with other polymers is thus of great interest and for the first time, film coextrusion process is used to create PLA-PEF and PET-PEF multi-micro/nano layered films. A new PEF grade developed by AVA Biochem in the H2020 Mypack program, has been used and firstly analysed in terms of melt processability, mechanical, thermal and gas barrier properties. Our major results confirmed the good gas barrier as well as mechanical properties of amorphous PEF. Post-extrusion PEF bulk thermal crystallization led to very brittle material making gas barrier measurements impossible. Micro/nanolayered PLA-PEF and PET-PEF films with different PEF layer thicknesses have been processed and post-extrusion annealing treatment was carried out. The relationship between crystallinity, mechanical and gas barrier properties will be investigated.
Modelling real contact areas caused by material straining effects in sheet metal forming simulation
Authors: Essig Peter , Liewald Mathias , Burkart Maximilian , Beck Maxim
Published: April 2021

Shortened product development processes in automotive industry combined with the upcoming lack of experts do challenge sheet metal part production fundamentally. Tryout time and manufacturing costs of large forming dies today are significantly influenced by their digitally supported engineering. The forming process by such tools is beside other influences is affected by elastic deformations of forming dies and press structure as well as contact areas between die and sheet metal part. In deep drawing such contact areas are influenced by the blank properties and the flange behavior in terms of thickening and thinning. Recent developments in sheet metal forming simulation do consider advanced friction models and structural modeling of die and press components improving simulation accuracy. Nevertheless thinning or thickening of sheet metal results into localized surface pressure distribution during deep drawing. For this reason, it is not sufficient to use the currently common practice of homogeneous surface pressure distribution in sheet metal forming simulation. In this respect, this paper presents a numerical approach for consideration of straining effects in the sheet metal part during forming operation. For this purpose, a systematic process improvement was developed in this paper to identify contact areas via a numeric simulation parameter. Validating the numerical investigation, a rectangle cup die is used, considering major strain. The main results of this contribution for that reason show how simulated contact areas can be estimated by reverse engineering of real forming parts. Hereby straining based contact areas lead to a novel contact area design in process planning, resulting in efficient die tryout.
Determination of Forming Limits Based on Finite Element Simulations
Authors: Shen Fuhui , Chen Kai , Lian Junhe , Münstermann Sebastian
Published: April 2021

Two categories of experiments have been performed to obtain the experimental forming limits of a ferritic stainless steel from uniaxial to equibiaxial tension, including Nakajima tests and tensile tests of flat specimens with different geometries of the central hole as well as the notched dog bone. The plasticity behavior of the investigated material is described using an evolving non-associated anisotropic plasticity model, which is calibrated based on experimental results of uniaxial tensile tests along different loading directions. A damage mechanics model is calibrated and validated based on the global force and displacement response of tensile tests. Finite element simulations of the Nakajima tests and the tensile tests of various geometries have been performed using the anisotropic material model. A novel spatio-temporal method is developed to evaluate the forming limits under different stress states by quantitatively characterizing the plastic strain distribution on the specimen surface. The forming limits have been independently determined from finite element simulation results of tensile specimens and Nakajima specimens using the spatio-temporal evaluation method. The forming limits obtained from numerical simulations of these two types of experiments are in good agreement with experimental results.
Determining Friction and Flow Stress of Material during Forging
Authors: Dixit Uday Shanker , Kumar Vikash , Petrov Pavel , Saprykin Boris
Published: April 2021

Determination of flow stress and friction in cold forging is of paramount importance. In this work, an inverse procedure is developed for predicting the Coulomb’s coefficient of friction and strain-dependent flow stress simultaneously based on the measurement of bulge and forging load. It is also established that in cold forging Coulomb’s coefficient of friction can be approximated as half the friction factor in Tresca (or constant friction) model. In the inverse procedure, forging load is estimated analytically but bulging is estimated by developing an empirical relation. The efficacy of the inverse procedure is ascertained by the data obtained from finite element method simulations. Finite element method was implemented in ABAQUS and validated with the results available in literature. In most of the cases, inverse procedure provides less than 5% error in the estimates of friction and flow stress. A sensitivity analysis is also carried out to study the effect of measurement error. It is observed that error in the estimation of friction is proportional to error in the measurement of bulge. The novelty of the method lies in the quickness and simplicity of the method.
Estimation of Stress-Strain behavior of polyethylene terephthalate (PET) at different strain rates by Artificial Neural Network under simultaneous stretch scenario
Authors: Teng Fei , Menary Gary , Malinov Savko , Yan Shiyong
Published: April 2021

In this paper, an Artificial Neural Network (ANN) is used to predict the stress-strain behavior of PET at conditions relevant to Stretch Blow Moulding i.e. Large equibiaxial deformation at elevated temperature and high strain rate. The input vectors considered are temperature, strain, and strain rate with a corresponding output parameter of stress. In the present work, a feed-forward back backpropagation algorithm was used to train the ANN. The ANN is able to approximate the relationship between stress and strain at various strain rates & temperatures to a high degree of accuracy for all conditions tested.
Temperature and contact pressure effects on the adhesion development of high performance thermoplastic composites
Authors: Avenet Julien , Corre Steven Le , Bailleul Jean-Luc , Levy Arthur
Published: April 2021

Thermoplastic composites offer new manufacturing prospects, thanks to the ability to melt the matrix. Welding, tape placement, 3D printing, overmoulding, or even stamping involve adhesion of the thermoplastic polymer at high temperature. First, under heat and pressure, contact at the microscopic scale is ensured by the deformation of surface roughness, this is the intimate contact step. Then, the development of the mechanical strength of the assembly is controlled by the diffusion of macromolecules at the interface which is defined as the healing step. Nowadays, continuous manufacturing processes tend to be faster and present very short residence time which could limit the adhesion development. A good understanding of these mechanisms is therefore very important to control and predict such industrial processes. Welding tests at different temperatures and contact pressures were carried out over a large range of residence times using a controlled welding bench enabling very short welding times (down to 1 second). The mechanical adhesion between PEKK-carbon composite samples was characterized using double cantilever beam fracture tests. Adhesion was found to develop in two steps which could be described as an intimate contact-healing coupled step and a pure healing step. From this, the healing kinetics was identified and an empirical model was developed to account for the effect of pressure on adhesion build-up. This model could then be compared with existing models to describe the establishment of intimate contact between the coupons.
Media-based forming of micro-flow channels into thin sheet metal by electromagnetically driven tools
Authors: Linnemann Maik , Scheffler Christian , Psyk Verena
Published: April 2021

The use of high-speed forming technologies can contribute to satisfying current social and political demands on production technology such as sustainability and climate protection in manufacturing. These technologies have a very high potential for shaping complex, sharp-edged parts and constitute a key means of reducing a component’s weight. One exemplary high-speed forming technology is electromagnetic forming. It uses the energy density of pulsed magnetic fields to impose forces on electrically conductive materials, which leads to plastic deformation when reaching the yield stress of the material. However, for very thin sheet materials this effect can result in an uncontrolled deformation of the work piece. In order to overcome this effect, electromagnetically driven tools the use of can be appropriate. An additional benefit is that this process is no longer restricted to electrically highly conductive work piece materials. This paper describes a media-based process using electromagnetically driven tools to form micro-flow channels, which are often used in bipolar plates, into thin sheet metals. The principles are explained and first results are shown.
Modelling of an induction heating process and resulting material distribution of a hybrid semi-finished product after impact extrusion
Authors: Behrens Bernd-Arno , Wester Hendrik , Schäfer Stefan , Büdenbender Christoph
Published: April 2021

Multi-material solutions offer benefits, as they, in contrary to conventional monolithic parts, are customised hybrid components with properties that optimally fit the application locally. Adapted components offer the possibility to use high strength material in areas where external loads require it and substitute them by lightweight material in the other areas. The presented study describes the manufacturing of a hybrid shaft along the process chain Tailored Forming, which uses serial pre-joined semi-finished products in the forming stage. Subject of this study is the numerical modelling of the heating process by induction heating of a hybrid semi-finished product and the resulting material distribution after the impact extrusion process. For this endeavour, a numerical model of an inhomogeneous induction heating process was developed. The main challenge is to determine the boundary conditions such as current intensity acting in the induction coil and the electromagnetic properties of the used material. The current intensity was measured by a Rogowski coil during experimental heating tests. The relative magnetic permeability was modelled as a function of temperature using the method of Zedler. The results show the importance of using a relative magnetic permeability as a function of temperature to guarantee a high quality of the numerical model. Subsequently, the model was applied to the heating of the hybrid semi-finished product consisting of a steel and aluminium alloy. By using inductive heating and thus a resulting inhomogeneous temperature field, good agreement of the material distribution between experiment and simulation could be achieved after the forming process.
Topology and FEA modeling and optimization of a patient-specific zygoma implant
Authors: Cholkar Abhijit , Kinahan David , Brabazon Dermot
Published: April 2021

Additive manufacturing has proven to be a very beneficial production technology in the medical and healthcare industries. While existing for over four decades, recent work has seen great improvements in the quality of products; particularly in medical devices such as implants. Improved customization reduced operating time and increased cost-effectiveness associated with Metal AM for these products offers a new value proposition.  This paper investigates and evaluates modelling methods for the zygoma bone (human jawbone) and explores the most suitable material and optimum design for this critical biomedical implant. This paper proposes an innovative and efficient pre-process methodology that includes modelling, design validation, topological optimization, and numerical analysis. The method includes the generation of the model using reverse engineering of CT scan data and a topology optimization technique which makes the implant lightweight without causing excessive stress concentration. Static structural Finite Element Analysis was conducted to test three different biocompatible materials (Ti6Al4V, stainless steel 316L and CoCr alloys) which are commonly available for metal additive manufacturing. The stresses and conditions in the analysis were that of the human mastication process and all the implant design were tested with the three material types. The Taguchi method was used to determine the optimum design which was found to result in the highest mass reduction of 25% with Ti6Al4V as the implant material.
Determination of Plastic Material Properties of Thin Metal Sheets under Electromagnetic Forming Conditions
Authors: Beckschwarte Björn , Herrmann Marius , Schenck Christian , Kuhfuss Bernd
Published: April 2021

Electromagnetic forming is a contactless high-speed forming technique. In this process force transmission is initiated by an electromagnetic field provided by a tool coil. While forming thin sheet metal, the magnetic field is present in the whole depth of the sheet metal by definition. Thus, the magnetic field generates eddy currents in the complete sheet volume. The resulting Lorenz` forces act as body forces and are used for forming. Thereby high strain rates, high temperatures and multiaxial stress fields influence the plastic material properties of the workpiece. In this study, the plastic properties were investigated under real electromagnetic forming conditions. By varying process conditions like charge energy, sheet thickness and die material, the magnetic field and thus the plastic material properties were changed. To visualize the influence of the electromagnetic field, forming experiments were carried out. The strain of the formed sheets was measured. Furthermore, the forming forces were determined by measurements during the electromagnetic forming as well as by finite element simulations. With the measured strain and the determined forming force, a model for the plastic material behavior during electromagnetic forming was evolved.
Challenges Encountered Applying Equilibrium and Non-Equilibrium Binding Free Energy Calculations
Authors: Baumann Hannah , Gapsys Vytautas , de Groot Bert L. , Mobley David
Published: April 2021

Binding free energy calculations have become increasingly valuable to drive decision making in drug discovery projects. However, among other issues, inadequate sampling can reduce accuracy, limiting the value of the technique.In this paper we apply absolute binding free energy calculations to ligands binding to T4 lysozyme L99A and HSP90 using equilibrium and non-equilibrium approaches. We highlight sampling problems encountered in these systems, such as slow side chain rearrangements and slow changes of water placement upon ligand binding. These same types of challenges are likely to show up in other protein-ligand systems as well and we propose some strategies to diagnose and test for such problems in alchemical free energy calculations. We also explore similarities and differences in how the equilibrium and the non-equilibrium approaches handle these problems. Our results show the large amount of work still to be done to make free energy calculations robust and reliable and provide insight for future research in this area.