Upaya Meningkatkan Hasil Belajar IPA pada Materi Bumi dan Alam Semesta melalui Metode Pembelajaran Numbered Heads Together pada Siswa Kelas VI SD Inpres 45 Kabupaten Sorong Semester II

Tujuan penelitian ini adalah meningkatkan hasil belajar ipa pada materi bumi dan alam semesta melalui metode pembelajaran numbered heads together pada siswa kelas VI SD Inpres 45 Kabupaten Sorong semester II tahun pelajaran 2015/2016. Penelitian ini merupakan penelitian tindakan kelas yang dilakukan di kelas VI SD Inpres 45 Kabupaten Sorong. Hasil Penelitian diperoleh Rata-rata aspek kognitif pada siklus I pertemuan ke I adalah 60,21 point dengan ketuntasan klasikal sebesar 29,20 % yang meningkat pada siklus I pertemuan ke II menjadi 62,29 dengan ketuntasan sebesar 45,83 %, kemudian pada siklus II pertemuan ke I meningkat menjadi 69,79 dengan ketuntasan klasikal sebesar 83,33% sedangkan pada pertemuan ke II menjadi 79,17 dengan ketuntasan klasikal sebesar 95,83%. Kesimpulan yang dapat diambil yaitu penggunaan pembelajaran NHT pada materi Bumi dan Alam Semesta dapat meningkatkan hasil belajar siswa kelas VI SD Inpres 45 Kabupaten Sorong tahun pelajaran 2015/2016 pada aspek kognitif maupun afektif pada siswa

UPAYA MENINGKATKAN HASIL BELAJAR IPA PADA MATERI BUMI DAN ALAM SEMESTA MELALUI METODE PEMBELAJARAN NUMBERED HEADS TOGETHER PADA SISWA KELAS VI SD INPRES 45 KABUPATEN SORONG SEMESTER II

Tujuan penelitian ini adalah meningkatkan hasil belajar ipa pada materi bumi dan alam semesta melalui metode pembelajaran numbered heads together pada siswa kelas VI SD Inpres 45 Kabupaten Sorong semester II tahun pelajaran 2015/2016. Penelitian ini merupakan penelitian tindakan kelas yang dilakukan di kelas VI SD Inpres 45 Kabupaten Sorong. Hasil Penelitian diperoleh Rata-rata aspek kognitif pada siklus I pertemuan ke I adalah 60,21 point dengan ketuntasan klasikal sebesar 29,20 % yang meningkat pada siklus I pertemuan ke II menjadi 62,29 dengan ketuntasan sebesar 45,83 %, kemudian pada siklus II pertemuan ke I meningkat menjadi 69,79 dengan ketuntasan klasikal sebesar 83,33% sedangkan pada pertemuan ke II menjadi 79,17 dengan ketuntasan klasikal sebesar 95,83%. Kesimpulan yang dapat diambil yaitu penggunaan pembelajaran NHT pada materi Bumi dan Alam Semesta dapat meningkatkan hasil belajar siswa kelas VI SD Inpres 45 Kabupaten Sorong tahun pelajaran 2015/2016 pada aspek kognitif maupun afektif pada siswa

El Contexto económico y la inversión social

Background of INCASI Project H2020-MSCA-RISE-2015 GA 691004. WP1: Compilatio

Viscoelastic Effects during Tangential Contact Analyzed by a Novel Finite Element Approach with Embedded Interface Profiles

A computational approach that is based on interface finite elements with eMbedded Profiles for Joint Roughness (MPJR) is exploited in order to study the viscoelastic contact problems with any complex shape of the indenting profiles. The MPJR finite elements, previously developed for partial slip contact problems, are herein further generalized in order to deal with finite sliding displacements. The approach is applied to a case study concerning a periodic contact problem between a sinusoidal profile and a viscoelastic layer of finite thickness. In particular, the effect of using three different rheological models that are based on Prony series (with one, two, or three arms) to approximate the viscoelastic behaviour of a real polymer is investigated. The method allows for predicting the whole transient regime during the normal contact problem and the subsequent sliding scenario from full stick to full slip, and then up to gross sliding. The effects of the viscoelastic model approximation and of the sliding velocities are carefully investigated. The proposed approach aims at tackling a class of problems that are difficult to address with other methods, which include the possibility of analysing indenters of generic profile, the capability of simulating partial slip and gross slip due to finite slidings, and, finally, the possibility of simultaneously investigating dissipative phenomena, like viscoelastic dissipation and energy losses due to interface friction

A framework for the analysis of fully coupled normal and tangential contact problems with complex interfaces

An extension to the interface finite element with eMbedded Profile for Joint Roughness (MPJR interface finite element) is herein proposed for solving the frictional contact problem between a rigid indenter of any complex shape and an elastic body under generic oblique load histories. The actual shape of the indenter is accounted for as a correction of the gap function. A regularised version of the Coulomb friction law is employed for modeling the tangential contact response, while a penalty approach is introduced in the normal contact direction. The development of the finite element (FE) formulation stemming from its variational formalism is thoroughly derived and the model is validated in relation to challenging scenarios for standard (alternative) finite element procedures and analytical methods, such as the contact with multi-scale rough profiles. The present framework enables the comprehensive investigation of the system response due to the occurrence of tangential tractions, which are at the origin of important phenomena such as wear and fretting fatigue, together with the analysis of the effects of coupling between normal and tangential contact tractions. This scenario is herein investigated in relation to challenging physical problems involving arbitrary loading histories.Comment: Final version available at https://www.sciencedirect.com/science/article/abs/pii/S0168874X2100089

A new finite element paradigm to solve contact problems with roughness

This article's main scope is the presentation of a computational method for the simulation of contact problems within the finite element method involving complex and rough surfaces. The approach relies on the MPJR (eMbedded Profile for Joint Roughness) interface finite element proposed in [arXiv:1805.07207], which is nominally flat but can embed at the nodal level any arbitrary height to reconstruct the displacement field due to contact in the presence of roughness. Here, the formulation is generalized to handle 3D surface height fields and any arbitrary nonlinear interface constitutive relation, including friction and adhesion. The methodology is herein validated with BEM solutions for linear elastic contact problems. Then, a selection of nonlinear contact problems prohibitive to be simulated by BEM and by standard contact algorithms in FEM are detailed, to highlight the promising aspects of the proposed method for tribology