Resumo: O ensino superior requer dos estudantes diversas estratégias e mecanismos que o tornam complexo, e a teoria do desenvolvimento cognitivo de Jean Piaget atua de forma basilar em tal compreensão, sendo um dos principais meios de investigação as atividades operatórias piagetianas (AOP). Portanto, objetiva-se apresentar uma revisão sistemática (RS) sobre pesquisas que investiguem aspectos cognitivos em discentes do ensino superior, por meio das AOP. Adotou-se o Protocolo Prisma para realização da RS em cinco bases de dados, obtendo-se um total de 38 documentos em aproximadamente 50 anos. Os resultados apontam para o surgimento de quatro tendências principais de pesquisas, bem como para um desenvolvimento cognitivo não condizente com o esperado em teoria, mostrando-se uma importante fragilidade no contexto do ensino superior, carente de ações afirmativas e educativas para elucidação. Por fim, apesar de meio século de pesquisas, essa temática se mostra atual e necessária, pois o conhecimento específico não pode, nem deve, ser desvinculado dos aspectos cognitivos no ambiente universitário.

Abstract: Higher Education is made complex due to the several strategies and mechanisms required from students, and Jean Piaget's theory of cognitive development acts in a fundamental way in such understanding. One of the main means of investigation is Piaget's operative activities. Therefore, the objective is to present a Systematic Review (SR) on research that investigates cognitive aspects in higher education students, through Piaget’s operative activities. The PRISMA Protocol was adopted for the realization of SR in five databases, obtaining a total of 38 documents in approximately 50 years. The results point to the emergence of four main research trends, as well as a cognitive development not consistent with what was expected in theory, showing an important weakness in the context of higher education, lacking affirmative and educational actions for clarification. Finally, despite half a century of research, this theme is current and necessary, since specific knowledge cannot, and should not, be disconnected from cognitive aspects in the university environment.

Resumen: La educación superior requiere de los estudiantes diversas estrategias y mecanismos que la hacen compleja, y la teoría del desarrollo cognitivo de Jean Piaget actúa de manera fundamental en tal comprensión, siendo uno de los principales medios de investigación las actividades operatorias de Piaget (AOP). Por tanto, el objetivo es presentar una revisión sistemática (RS) sobre investigaciones que estudien aspectos cognitivos en estudiantes de educación superior, a través de las AOP. Se adoptó el Protocolo Prisma para la realización de la RS en cinco bases de datos, obteniendo un total de 38 documentos en aproximadamente 50 años. Los resultados apuntan a la emergencia de cuatro grandes tendencias de investigación, así como a un desarrollo cognitivo no acorde con lo esperado en teoría, mostrando una importante debilidad en el contexto de la educación superior, careciendo de acciones afirmativas y educativas para el esclarecimiento. Finalmente, a pesar de medio siglo de investigaciones, este tema es actual y necesario, ya que los conocimientos específicos no pueden ni deben desconectarse de los aspectos cognitivos en el ámbito universitario.

Este trabalho trata da análise dos centros de massa e do cálculo da estabilidade das quatro posturas básicas do Kung Fu Pak Hok. Embora a biomecânica tenha surgido em 1960, a sua aplicação em artes marciais, como no Kung Fu ainda é pouco frequente. Apesar de haver estudos de movimentos do Kung Fu, não há trabalhos sobre o centro de massa e a estabilidade para as posturas mais básicas. Este trabalho como objetivo descrever o centro de massa e a estabilidade das quatro posturas mais básicas do Kung-fu Pak Hok usando o método analítico por imagem de forma que seja possível sua utilização no ensino de física de forma contextualizada, e também em conjunto com a Educação Física. O cálculo da estabilidade foi realizado por meio do conceito de estabilidade entre os torques estabelecidos entre a força peso e uma força desestabilizadora. Os centros de massa em cada uma das quatro posturas se mantiveram muito próximos da região do umbigo. Foi verificado que as posturas mais estáveis corroboram com estâncias mais defensivas enquanto que posturas mais instáveis corroboram com estâncias mais ofensivas. Com isso, a análise quantitativa está de acordo com o conhecimento cultural e qualitativo associado ao Kung-fu.

In this paper we analyse the mass center and the postural stability of four basic Kung Fu Pak Hok postures. Although biomechanics arose in 60's, its application in martial arts such as Kung Fu, isn't often. There are few case studies which accounts the movements of Kung Fu, however there are none based on the study of its mass center and stability of its basic postures. This paper has as objective to describe the mass center and the stability of each of the four most basic postures of the Kung Fu Pak Hok using the image analytical method in a way that is possible to assemble Physics and Sports in an educational context. In order to calculate the mass center of each posture, it was carried out the image analytical method. The stability calculation was carried out by means of the equilibrium concept associated to the torques generated by the weight force and a destabilizing force. The mass center for each of the four postures was about the belly button. Also, it was noticed that the most stable postures were associated to defensive stances while unstable postures were associated to offensive stances. Nevertheless, the quantitative analysis stand on tune with the qualitative approach linked to the cultural background in the Kung Fu martial art.

Mechanical and tribological properties os AISI 304 and AISI 316 stainless steels submited to glow discharge ion nitriding are reported.The atmosphere was 20:80 - N2:H2 with substrate temperatures ranging from 300 to 500 °C. Treatment at 300 °C produced expanded austenite (γN) in both steels. Increasing the temperature, the phases γ´-Fe4N and - Fe2+xN were present and the latter is the major phase for AISI 304. At 500 °C, the CrN phase was also identified in both steels. Hardnesses of about 13-14 GPa at near surface regions were obtained in both steels. Moreover, AISI 316 nitrided at 500 °C has the deepest hard layer. Tribological tests showed that wear can be reduced by up to a factor of six after the nitriding processes, even for a working temperature of 300 °C. The profiles during and after nanoscratch tests did not reveal significant differences after nitriding processes in both steels.

The nanoindentation technique allows the determination of mechanical properties at nanometric scale. Hardness (H) and elastic modulus (E) profiles are usually determined by using the Oliver-Pharr method from the load/unload curves. This approach is valid only for flat surfaces, or at least, when a very low degree of asperity is present (lower than 30 nm). The basic statement is the determination of the zero tip-surface contact point. If a rough surface is present, errors can occur in determining this contact point and, as a consequence, the surface hardness and elastic modulus profiles are drastically altered resulting in under evaluated values. Surfaces with different roughness were produced by controlled nitrogen glow discharge process on titanium. The changed nitriding parameters were different N2/H2 atmospheres and temperatures (600 °C-900 °C). The most correct H and E profiles were obtained by using the contact stiffness analysis method, proposed here, that overcomes the surface roughness. The obtained results were compared with available literature data.