Multiscale Experimental Analysis in Plasticity: Linking Dislocation Structures to Continuum Fields

Plastic deformation in metals is a complex phenomenon and is result of competition between different complicated mechanisms, and among all, dislocation nucleation and motion are the most dominant ones. Dislocation evolution is known to be a multiscale phenomenon, and has been incorporated to crystal plasticity theories to analyze the size effect in metals for almost a decade ago. Although the theories suffice to predict the size effect in metals, they are largely phenomenological. Here a novel experimental method is developed to resolve the complexity in plastic deformation due to dislocations and to extract new material length scales that can be incorporated to numerical models. A continuum-based quantity: the geometrically necessary dislocation density (GND) that describes the signed part of the overall dislocations is measured on a nickel single crystal sample using recently developed high resolution electron backscatter diffraction (HR-EBSD) over different field of view, 90 μm^2 − 1mm^2 with various step sizes, 50 nm to 2, 500 nm . The net Burgers vector density, which includes the information of the direction of the overall dislocation motion and also quantifies the flux of atoms changing positions due to dislocations, is measured for the first time using continuum methods. A new parameter, β, that is extracted from the net Burger vector density to monitor dislocation activity on crystallographic slip planes is measured. Measurements reveals patterning in GND densities and a distribution of length scales rather than a single length scale as assumed. The length scales, such as dislocation spacing, and dislocation cell sizes are quantified. The linear relationship between dislocation spacing and dislocation cell size is obtained, where the slope of the linear fit varies with different crystallographic slip systems and the number of the active slip systems. The slope ranges between 23-29 for dominantly single slip regions, whereas it ranges between 13-16 for multislip regions, which agrees with the findings from TEM analysis in the literature showing how a continuum based method can be used to obtain same material parameters. The experimental measurements and the assumptions are elaborated in a detailed analysis. The effect of step size in EBSD results is presented, and the information loss with increasing the step size is shown. The uncertainty in GND density from the HR-EBSD measurements is found to be 10^13, which is two order of magnitude less than results from traditional diffraction methods. The effect of dislocation mobility on microstructure evolution has been also investigated, specifically tantalum single crystal specimens tested at 77 K and 293 K. The results unraveled occurrences of different deformation mechanisms: kink shear, and twinning at low temperatures. Interactions between dislocations and twin formations are observed and striking microstructure differences are examined. The dislocations density measurement results on tantalum are unique in the experimental sense and data can be used to extract length scale information. The experimental observations have been exploited to build the foundations of a numerical model. The effect of microstructure evolution on mechanical response has been investigated numerically based upon experimental observations. One of the main outcome of the experimental analysis -the variation of GND densities in cell walls- has been incorporated into a strain gradient plasticity framework. The proposed model is demonstrated with constrained shear and pure bending problems. The results presented show patterning in the GND density profile depending on the prescribed initial variation of the saturation value of GND densities and also change in overall mechanical response depending on the complexity of the prescribed profile

Penggunaan Metode Kerja Kelompok dalam Pembelajaran Ilmu Pengetahuan Alam untuk Meningkatkan Hasil Belajar Siswa

This study aimed to describe improving student learning outcomes in breeding plants generative in sixth grade STATE 11 Nanga Relatives . This research uses descriptive method and form of research is the PTK . Research subjects that teachers and six graders STATE 11 Nanga Relatives totaling 18 people . Data collection techniques are directly techniques and data collection tool that observation sheets , ( IPKG IPKG I & II ) and student learning outcomes . Data were analyzed by calculating the average. Student learning outcomes in the first cycle obtained an average value of 60 and the second cycle of the average value of 76.11 with an increase 16.11 . Achievement of KKM is 60 in the first cycle of students who completed 11 or 61.16 % and the second cycle as many as 17 people or 94.5 % with an increase of 33% . By using the method of group work can improve learning outcomes six graders STATE 11 Nanga Relatives

Inclusive Education in Indonesia: Equality Education Access for Disabilities

Based on data from the World Bank, one out of ten poor people around the world is the disabled. Poverty experienced by the disabled is a direct and indirect result of the exclusion and marginalization of people with disabilities because of the stigma and prejudices about disability. One of the stigma and prejudice on people with disabilities arise in the educational setting. The United Nations [UN] report showed that 90 % of all children with disabilities in developing countries still do not attend school, and the literacy rate of adults disabled predicted only 1 % (United Nations). Since Indonesia ratified Salamanca declaration, about equal education access for persons with disabilities, some inclusive schools begin to set in Indonesia. The government started affirming that Children With Special Needs (CWSN) basically has the right to education as normal children, without discriminated, by placed CWSN in special schools that are different from normal children. This article attempts to review various studies regarding the implementation of inclusive schools in Indonesia, to get a picture about the process of eliminating discrimination against students with special needs in Indonesian school.     Keywords: Disabled, Equality Education Access, Inclusive Education, Lampung, Metr

Metode Naive Bayes untuk Prediksi Kelulusan (Studi Kasus: Data Mahasiswa Baru Perguruan Tinggi)

Timetables system, genetic algorithm, timetable at universityClassifier created from a set of data. Bayesian classifier is a statistical classifier for predicting the probability of a particular class membership. This research will try to perform data classification for prediction of new student graduation, Naive Bayes algorithm method used for naïve Bayes classification performance high enough ability to predict future opportunities based on experience or data in the past. Imlementation WEKA algorithms in applications that will explore the characteristics of the dataset with superficial attributes Pass options. Evaluation results show classified data correctly (correct classified instances) in accordance with the grouping of choice graduated first choice, second choice and do not pass by the algorithm as much as 93.6288% or as much as 338 data and classified data, but does not match the class predicted (incorrect classified instances ) which should be a group of two or Pass options but are included in the group First choice as many as 6.3712% or as much as 23 data. Value Percentage accuracy demonstrated the effectiveness dataset Admissions applied to the methods Naïve Bayes Classification, which reached 94

Desa dan Hukum Adat : Persepektif Normativitas dan Sosiologis Keindonesiaan

Kajian ini menganalisis terhadap eksistensi desa yang merupakan masyarakat hukum adat dan hukum adat yangmemiliki korelasi dan ikatan yang kuat pada masyarakat hukum adat. Berbagai literature berkaitan tentang desa danberbagai aturan yang dibuat oleh pemerintah tentang desa telah menempatkan desa sebagai basis kekuatan dasar dangarda terdepan dalam menjaga nilai-nilai originalitas lokal (local wisdom). Philosophische grondslag dalam strukturkeyakinan bangsa Indonesia telah menempatkan nilai-nilai tersebut sebagi salah satu soko dasar pembangunanmasyarakat Indonesia. Paradigma yang mendasar desa dan hukum adat sebagai kehidupan masyarakat yangterintegrasi, karena nilai-nilai dasar yang dibangun dalam masyarakat desa adalah nilai-nilai hukum adat yangdiyakini sebagai kakuatan dasar terhadap pembangunan kultur budaya ke-Indonesiaan yang multikulturalisme danpluralisme. Dalam kajian ini menunjukan bahwa desa dan hukum adat merupakan satu kesatuan terintegrasi dalamsistem kehidupan masyarakat Indonesia, sehingga legitimasi bagi desa dan masyarakat hukum adat merupakan ciridan kekhasan dari nilai-nilai lokalitas yang terbangun secara beriringan. Tujuan penelitian adalah mengkaji sudutpandang relasi antara desa dan hukum adat. kajian ini menggunakan penelitian doktrinal dengan pendekatanfilosofis dan peraturan Perundang-undangan.

Keanekaragaman Jenis Vegetasi pada Hutan Rawa Gambut Sekunder dan Belukar Rawa Desa Sungai Pelang Kabupaten Ketapang

Peat swamp forest has a valuable natural richness in the form of plants. This study aimed to find out the composition and dominance of species, species diversity, and stand structure in secondary peat swamp forest and thicket swamp. The vegetation analysis in secondary peat swamp forest and thicket swamp is done by using combination method. Mentibu (Daetylocladus stenostachys Oliver) is dominant in secondary peat swamp forest of tree growth level, and mempening (Quercus conocarpa OUD) is dominant in pole, sapling, and seedling of growth level (INP = 34,74%, 32,57%, 28,96%, respectively). In thicket swamp, prepat (Combretocarpus rotundatus Danser) is a dominant for the whole of growth level (INP = 261.89%, 126,12%, 98.96%, 64.99%, respectively). The diversity index of Shannon-Wienner (H) in secondary peat swamp forest is abundant (H > 1) and low in thicket swamp (H < 1). The secondary peat swamp forest have a normal stand structure according to de Liocourts law. In thicket swamp, the forest had been fire, but the vegetation development now has led to a succession of normal vertical forest structure and almost reach climax. Keywords: Peat swamp forest, composition and dominance of species, species diversity and stand structure

Peningkatan Hasil Belajar Siswa pada Pembelajaran IPS Menggunakan Metode Kerja Kelompok di Sekolah Dasar

The aim of this study describes the use of group work methods to improve learning outcomes material natural resources class IV SDN 14 Covering Bengkayang. The method used is descriptive method with the form of classroom action research. The research subjects were teachers as researchers and 27 students. Based on the data analysis capabilities of teachers planning teaching in the first cycle an average of 2:52 to an average of 3 on the second cycle. The ability of teachers to implement learning in Cycle I mean 2:35 to an average of 3 on the second cycle. Student learning outcomes of the first cycle the average percentage of completeness 6:15 by 55.6%, rising to an average of 7:04 with the completeness percentage 89.9% in the second cycle. Based on this it is concluded that learning through group work method can improve learning outcomes IPS fourth grade students of SDN 14 Covering Bengkayang

Tingkat Kepedulian Masyarakat Pesisir dalam Melestarikan Fungsi Hutan Mangrove dan Hutan Payau di Desa Sukabaru Kabupaten Ketapang

Society with mangrove forest ecosystem and brackish forest ecosystem that raises the existence of public awareness in preserving the function of mangrove forest and brackish forest. The method used is survey method with descriptive associative and used interview techniques with instrument a questionnaire. There are two types of data analysis namely descriptive analysis used to see the general description characteristic of respondents and the level of public awareness and inferential analysis used to know different levels of income people who worked as fishermen and does not worked as fishermen by using independent sample t-test and to know the factors that affect the level of public awareness by using multiple linear regression models. The level of public awareness coastal in preserving function mangrove forest and brackish forest is tend high. The results of independent sample t-test indicated there was no significant difference between the average income levels of people who worked as fishermen with an average income levels of people who does not worked as fishermen. Based on the analysis used multiple linear regression models was knowledge variables and cosmopolitan variables significantly influence the level of public awareness, while age variables, income variables, and perceptons variable were not significantly influence the level of public awareness. Keywords: The level of public awareness, mangrove forest, brackish fores