Analisis Pengaruh Salinitas Dan Suhu Air Laut Terhadap Laju Korosi Baja A36 Pada Pengelasan SMAW

Korosi merupakan masalah serius yang terjadi pada logam karena bisa mengurangi nilai ekonomis dari logam tersebut. Korosi pada baja kapal dipengaruhi oleh kondisi lingkungan seperti kadar salinitas dan suhu air laut. Tulisan ini membahas hasil penelitian yang dilakukan untuk mengetahui pengaruh salinitas dan suhu air laut terhadap laju korosi baja kapal A36 pada pengelasan SMAW menggunakan pengujian sel tiga elektroda. Elektroda yang digunakan adalah AWS A5.1 E6013. Suhu yang digunakan adalah 70C, 170C, 270C. Salinitas yang digunakan adalah 320/00, 350/00 dan 380/00. Hasil pengujian menunjukkan jika semakin besar suhu dan salinitas, maka semakin besar pula laju korosinya. Korosi terbesar terjadi pada salinitas 380/00 dengan suhu 270C yaitu sebesar 0,5616 mmpy. Penambahan laju korosi setiap kenaikan suhu 100C sebesar 0,2052 mmpy. Sedangkan penambahan laju korosi setiap kenaikan salinitas 30/00 sebesar 0,0415 mmpy

Peningkatan Aktivitas Belajar dengan Pendekatan Kooperatif Tipe Stad dalam Pembelajaranilmu Pengetahuan Sosial

; Increased Activity Learning With Type STAD Cooperative Approach in Teaching Social Studies Fourth Grade Elementary School District 31 Sumiak Porcupine District. This study aims to improve students\u27 learning activities using cooperative approaches to learning STAD Type of Social Sciences. Benefits of this research is to provide new knowledge and skills through a variety of actions that the teacher in action research. Forms of research used was Classroom Action Research with the kind of research that examined the performance kualitatif.Indikator approach is physical activity, mental activity and emotional activity with at least 65% completeness criteria of student attendance. namely physical activity ranging from the base line to the second cycle in a row is 20.83%, 44.16%, and 67.49%, mental activity ranging from base line to the second cycle in a row is 3.12%, 37.49%, and 65.62%. Emotional activity ranging from base line to the second cycle in a row is 8.33%, 46.66%, and 72.49%, thus the research using STAD cooperative approach can improve students\u27 learning activities

Two-dimensional Vesicle dynamics under shear flow: effect of confinement

Dynamics of a single vesicle under shear flow between two parallel plates is studied using two-dimensional lattice-Boltzmann simulations. We first present how we adapted the lattice-Boltzmann method to simulate vesicle dynamics, using an approach known from the immersed boundary method. The fluid flow is computed on an Eulerian regular fixed mesh while the location of the vesicle membrane is tracked by a Lagrangian moving mesh. As benchmarking tests, the known vesicle equilibrium shapes in a fluid at rest are found and the dynamical behavior of a vesicle under simple shear flow is being reproduced. Further, we focus on investigating the effect of the confinement on the dynamics, a question that has received little attention so far. In particular, we study how the vesicle steady inclination angle in the tank-treading regime depends on the degree of confinement. The influence of the confinement on the effective viscosity of the composite fluid is also analyzed. At a given reduced volume (the swelling degree) of a vesicle we find that both the inclination angle, and the membrane tank-treading velocity decrease with increasing confinement. At sufficiently large degree of confinement the tank-treading velocity exhibits a non-monotonous dependence on the reduced volume and the effective viscosity shows a nonlinear behavior.Comment: 12 pages, 8 figure

Analisa Teknis Dan Ekonomis Pemilihan Manajemen Air Ballas Pada Kapal (Ship Ballast Water Management) Di Indonesia

Peraturan yang mengatur dan manajemen dari air ballas dikeluarkan oleh IMO (International Maritime Organization) melalui konvensi Manajemen air ballas. Konvensi tersebut menyatakan bahwa organisme yang berbahaya terhadap lingkungan, kesehatan manusia, properti atau sumber daya merusak keanekaragaman hayati atau mengganggu pemanfaatan terhadap suatu area jika dilepaskan di air laut. Pemerintah Republik Indonesia mengeluarkan Peraturan Presiden No. 132 tahun 2015 mengenai pengesahan Konvensi Internasional untuk pengendalian dan manajemen air ballas dan sedimen dari kapal 2004 (The International Convention for the control and management of ships ballast water and sediment's 2004). Penelitian ini bertujuan untuk menganalisa sejauh mana kesiapan Indonesia dalam ratifikasi peraturan (come into force) Ballast water Management serta dampak yang diakibatkan setelah peraturan tersebut diratifikasi. Metode yang dilakukan dalam penelitian ini menggunakan 3 pendekatan yaitu dari aspek hukum, aspek teknis dan aspek ekonomis. Hasil dari penelitian ini adalah Peraturan Pemerintah Nomor 21 Tahun 2010 tentang Perlindungan Lingkungan Maritim sebagai jabaran dari Undang-Undang Nomor 17 Tahun 2008 tentang Pelayaran, telah sejalan dengan Konvensi Internasional untuk Pengendalian dan Manajemen Air Ballas dan Sedimen dari Kapal, 2004 dan Undang-Undang Nomor 17 Tahun 1985 tentang pengesahan United Nations Convention on the LAW of the Sea (UNCLOS). Serta Penggunaan sistem manajemen air ballas untuk kapal di perairan Indonesia lebih efektif dan efisien menggunakan filtration + electrolysi

A quantitative theory of current-induced step bunching on Si(111)

We use a one-dimensional step model to study quantitatively the growth of step bunches on Si(111) surfaces induced by a direct heating current. Parameters in the model are fixed from experimental measurements near 900 deg C under the assumption that there is local mass transport through surface diffusion and that step motion is limited by the attachment rate of adatoms to step edges. The direct heating current is treated as an external driving force acting on each adatom. Numerical calculations show both qualitative and quantitative agreement with experiment. A force in the step down direction will destabilize the uniform step train towards step bunching. The average size of the step bunches grows with electromigration time as t^beta, with beta = 0.5, in agreement with experiment and with an analytical treatment of the steady states. The model is extended to include the effect of direct hopping of adatoms between different terraces. Monte-Carlo simulations of a solid-on-solid model, using physically motivated assumptions about the dynamics of surface diffusion and attachment at step edges, are carried out to study two dimensional features that are left out of the present step model and to test its validity. These simulations give much better agreement with experiment than previous work. We find a new step bending instability when the driving force is along the step edge direction. This instability causes the formation of step bunches and antisteps that is similar to that observed in experiment.Comment: 11 pages, 7 figure

Pharmacogenomics in the UK National Health Service: opportunities and challenges

There is increasing interest in pharmacogenomics. However, it is also widely acknowledged that implementation of pharmacogenomics into clinical practice has been slow. Implementation is being undertaken in many centres in the US, but this is not nationwide and often focused on highly specialised academic centres, driven by champions. To date, there has been no implementation on a whole country basis. The UK National Health Service (NHS) is a single integrated healthcare system, which provides free care to all patients at the point of need. Recently, there has been a drive to implement genomic medicine into the NHS, largely spurred on by the success of the 100,000 genomes project. This represents an unprecedented opportunity to implement pharmacogenomics for over 60 million people. In order to discuss the potential for implementing pharmacogenomics into the NHS, the UK Pharmacogenetics and Stratified Medicine Network, NHS England and Genomics England invited experts from academia, the healthcare sector, industry and patient representatives to come together to discuss the opportunities and challenges1. This report highlights the discussions of the workshop with the aim of providing an overview of the issues that need to be considered to enable pharmacogenomic medicine to become mainstream within the NHS

The investigation of sustainable environmental performance of manufacturing companies: mediating role of organizational support and moderating role of CSR

China is transitioning towards green and sustainable manufacturing, considering environmental measures as per external environment demands. This research investigates the impact of green entrepreneurial orientation, social entrepreneurship, and organizational ambidexterity on sustainable environmental performance. Besides, examining the mediating role of organizational support and moderating the role of corporate social responsibilities (CSR) are also included in the aim of this research. The present study has used quantitative data of 510 respondents from China’s manufacturing industry; further structural equation modelling (SEM) was employed to analyse the data. The results revealed that organizational ambidexterity, green entrepreneurial orientation, and social entrepreneurship are positively associated with sustainable environmental performance. Organizational support positively mediates among the nexus of green entrepreneurial orientation, social entrepreneurship, and sustainable environmental performance. The findings also showed that CSR significantly moderates the relationship between organizational support and sustainable environmental performance. These outcomes provide various implications for policymakers while making policies regarding CSR and sustainable environmental performance