The effect of external grit particle size on friction coefficients and grit embedment of brake friction material

Changes in friction and contact surfaces characteristics of a brake friction material during drag and stop mode test were investigated using a brake model tribo-tester. Scanning Electron Microscopy (SEM) was utilized to reveal the surface topography characteristics and analyze the external particle size effects on friction coefficients and grit embedment. Silica sand with three different particle sizes of 50-180 µm, 180-355 µm and 355-500 µm was used in this work. At higher disc sliding speed, results showed that small grit particles cause higher friction due to greater frequency of particles mixing and modifying the effective contact compared to bigger particles. Good friction stability was attributed to smaller particles size providing more stable contact by actively involved in building up and reducing the rate of changes of the effective contact area. Through SEM analysis, signs of formation and disintegration of contact plateaus correlated well with particle size and hence, suggesting the significant role of particle size as wearing mechanism. Grit embedment (GE) was greatly dependent on presence of compacted wear debris as most particles were found embedded into compacted wear debris. Total GE of 2.7% was observed for silica sand of 50-180 µm, 4.5% for 180-355 µm and 3.0% for 355-500 µm

Fragmentation and Conflict Among Islamic Political Parties in Indonesia During Reformasi Era (1998-2009): Anatomy, Factors and Implications

Since independence of the Republic of Indonesia, Muslims, as the majority population, have established diverse Islamic political parties. The nature of such parties has changed from the days of the Old Order to the New Order and Reformasi eras. Despite similar anatomies between Islamic parties of the Old Order and those of Reformasi, Islamic political parties profess different ideological missions. While the beginning of Old Order saw the confederation of Islamic political parties, Masyumi, seeking to promote the establishment of an Islamic State, none of the Islamic political parties which mushroomed during Reformasi era expressly struggled for the establishment of an Islamic state. However, the Islamic political parties had to weather similar problems of internal conflict and fragmentation. Different ideological strands, policy stances and leadership styles are believed to be amongst the pivotal root causes of their domestic troubles. With their popular votes and parliamentary seats significantly reduced, they prove to be no competition to the nationalist political parties

Analisa Perencanaan Lumpur pada Lapisan Saltdome Lapangan X Sumur Y

Formasi Garam (saltdome) merupakan formasi yang yang mengandung sodium klorida yang dapatmasuk kedalam sistem lumpur pemboran. Apabila menggunakan lumpur bentonite, garam akanmasuk kedalam lumpur dan menyebabkan flokulasi pada lumpur. Sebelum menembus targetformasi pemboran sumur Y-3, pemboran akan melewati formasi Ezanga yang merupakan lapisangaram yang kaya akan garam anhydrite. Lapisan garam merupakan formasi yang reaktif dan sulituntuk ditembus.Selain formasi yang reaktif, pada formasi Ezanga juga memiliki tekanan yangabnormal dan bertekanan rekah rendah.Untuk menembus formasi Ezanga digunakan lumpur SaltSaturated Polimer

ANALISIS PENGARUH LAJU PEMBEBANAN TERHADAP KUAT TEKAN UNIAKSIAL BATU GAMPING DAN BATU PERIDOTIT

Penelitian ini menggunakan dua jenis sampel batuan yaitu sampel batu gamping yang diambil di PT. Diamond Alfa Propertindo, Kecamatan Mawasangka Tengah, Kabupaten Buton Tengah dan sampel batu peridotit yang diambil di PT. Karyatama Konawe Utara (KKU), Kecamatan Langgikima, Kabupaten Konawe Utara. Penelitian ini bertujuan untuk mengetahui pengaruh laju pembebanan terhadap kuat tekan uniaksial batu gamping dan batu peridotit. Metode yang digunakan pada penelitian ini yaitu uji kuat tekan uniaksial (UCS), yang merupakan uji untuk menentukan kekuatan batuan di bawah satu komponen tegangan (uniaksial). Sampel yang akan digunakan pada pengujian ini berbentuk silinder yang akan ditekan sampai sampel batuan tersebut mengalami keruntuhan dengan menggunakan mesin tekan (Compression Machine). Jumlah sampel yang digunakan yaitu 6 sampel (3 sampel batu gamping dan 3 sampel batu peridotit) kemudian akan di uji kuat tekan uniaksial dengan laju pembabanan 15000 KPa/s (15 MPa/s), 30000 KPa/s (30 MPa/s) dan 50000 KPa/s (50 MPa/s). Hasil penelitian dari uji kuat tekan uniaksial pada batu gamping dengan kode sampel SG 1 memiliki nilai tertinggi yaitu 4,78 MPa, sedangkan SG 2 dan SG 3 memiliki nilai 4,01 MPa dan 3,82 MPa. Untuk kuat tekan uniaksial batu peridotit nilai yang paling tinggi dimiliki oleh sampel dengan kode SP 1 yaitu 2,73 MPa, sedangkan sampel dengan kode SP 2 memiliki nilai 2,43 MPa dan SP 3 memiliki nilai sebesar 2,12 MPa. Berdasarkan hasil analisis laju pembebanaan terhadap nilai kuat tekan uniaksial pada batu gamping dan batu peridotit diperoleh bahwa laju pembebanan mempengaruhi nilai kuat tekan uniaksial dan memiliki hubungan yang bersifat kebalikan atau negatif dimana seiring dengan dinaikkan laju pembebanan maka nilai kuat tekan uniaksial batu gamping dan batu peridotit menurun.Penelitian ini menggunakan dua jenis sampel batuan yaitu sampel batu gamping yang diambil di PT. Diamond Alfa Propertindo, Kecamatan Mawasangka Tengah, Kabupaten Buton Tengah dan sampel batu peridotit yang diambil di PT. Karyatama Konawe Utara (KKU), Kecamatan Langgikima, Kabupaten Konawe Utara. Penelitian ini bertujuan untuk mengetahui pengaruh laju pembebanan terhadap kuat tekan uniaksial batu gamping dan batu peridotit. Metode yang digunakan pada penelitian ini yaitu uji kuat tekan uniaksial (UCS), yang merupakan uji untuk menentukan kekuatan batuan di bawah satu komponen tegangan (uniaksial). Sampel yang akan digunakan pada pengujian ini berbentuk silinder yang akan ditekan sampai sampel batuan tersebut mengalami keruntuhan dengan menggunakan mesin tekan (Compression Machine). Jumlah sampel yang digunakan yaitu 6 sampel (3 sampel batu gamping dan 3 sampel batu peridotit) kemudian akan di uji kuat tekan uniaksial dengan laju pembabanan 15000 KPa/s (15 MPa/s), 30000 KPa/s (30 MPa/s) dan 50000 KPa/s (50 MPa/s). Hasil penelitian dari uji kuat tekan uniaksial pada batu gamping dengan kode sampel SG 1 memiliki nilai tertinggi yaitu 4,78 MPa, sedangkan SG 2 dan SG 3 memiliki nilai 4,01 MPa dan 3,82 MPa. Untuk kuat tekan uniaksial batu peridotit nilai yang paling tinggi dimiliki oleh sampel dengan kode SP 1 yaitu 2,73 MPa, sedangkan sampel dengan kode SP 2 memiliki nilai 2,43 MPa dan SP 3 memiliki nilai sebesar 2,12 MPa. Berdasarkan hasil analisis laju pembebanaan terhadap nilai kuat tekan uniaksial pada batu gamping dan batu peridotit diperoleh bahwa laju pembebanan mempengaruhi nilai kuat tekan uniaksial dan memiliki hubungan yang bersifat kebalikan atau negatif dimana seiring dengan dinaikkan laju pembebanan maka nilai kuat tekan uniaksial batu gamping dan batu peridotit menurun

Analisis Pendampingan Pelaksanaan Community Base Management (Cbm) Pada Program Coral Reef Rehabilitation and Management (Coremap) Di Kawasan Taman Nasinaol Takabonerate Selayar

This research was conducted in the islands of the National Park neighborhood Takabonerate Selayar, namely in Rajuni Island, Island and Island Tarupa Latondu. Judging from the nature of research is exploratory, namely exploration (exploration) in order to find the right answer and the right of the subject matter of the study. Without the same hypothesis, but rather to establish proposes I -proposisi continuously until missed the entire research problems. Judging from the object of research is sosioogis empirical, that is the main subject of research with empirical facts of sociology on the protection of coastal areas against environmental damage. The data collection is done by in-depth interviews and observations based on the guidelines for the interview (Interview Guide) that had been prepared in advance. The informant is determined intentionally (purposive) against the Companion / Facilitator Fields, leader of the group / retainer and members of fisherman, and his wife and family fishermen recruited as a representation of the 3 islands samples (Rajuni Island, Island and Island Latondu Tarupa)

Penerapan Model Pembelajaran Discovery Tipe Guided Discovery dalam Upaya Meningkatkan Hasil Belajar Fisika Siswa Kelas XI Mipa 2 di Sman 16 Banda Aceh

This type of research is the Classroom Action Research (PTK) and the approach used in this study is the quantitative approach. The data used in this study comes from the class XI students of Mathematics and Science 2 SMAN 16 Banda Aceh the school year 2016/2017 with the number of 19 learners. Data collection instrument in this study is the observation sheets, test in the form of pre-test and post-test, and questionnaire responses of learners that the three analyzed using percentages test. The result showed that (1) an increase in activity of teachers and learners during the learning process in each cycle, (2) an increase in teachers' skills in managing learning in each cycle of the category enough to be very good, (3) the percentage of completeness learners whole increased from cycle 1 to cycle 3, namely 58%, 74% and 89%, and (4) the learners tend to be positive in that 95% of learners said he was happy and able to understand the learning by using model-type Guided Discovery Discovery. Based on data obtained from this study can be concluded that the application of learning models Guided Discovery Discovery type can improve learning outcomes of students in the subject matter On Newton's Law of Gravity

Empowering Coastal Community by Implementing Natural Resources Management (Case Study in Southeast Sulawesi, Indonesia)

Economic crisis in 1997-1998 had brought about the emergence of problems of coastal communities in Indonesia, including those in Southeast Sulawesi. Most of the problems still have taken place at present, leading to the degradation of ecosystem services for natural resources. Development activities in various sectors done through unsustainable practices of utilization of natural resources have contributed to increased environmental degradation , which resulted in drastically decreased on fish population. Recently, the government and people are aware that integrated natural resources of coastal and marine management have to be set based on scientific approach. There have been several strategies formulated. Among them is integrated coastal zone management, but unfortunately it has been using top down approach. Hence, local community has no access to the programs. The effective implementation of empowerment should involve all stakeholders who have access to the coastal resources. The objectives of this work were to reduce gradually coastal resources degradation, to change fishermen behavior using illegal fishing, and to create new job using natural resources. This work was implemented in Lasongko Bay of Buton island. The present work is formulated to reduce social economic problems, which has strong correlation with environmental degradation. The programs were formulated by local community in several discussion forums based on identification of their natural resources. To alleviate poverty, rehabilitation of environmental degradation was done first which consisted of planting mangrove seeds along shoreline of the bay and establishing marine protected area. Another program implemented was fish and seaweed cultures to improve community income. The local community in groups took full participation and involvement in all programs implemented due to the role of religion and traditional figures and youth leaders. To achieve the objectives and goals of the programs, each group had a leader and held monthly meeting to discuss strategies for better life. All programs implemented showed better hope for the future due to active participation of local community in maintaining all programs of environment rehabilitation. Similarly, activities of improving income also showed better production

Perhitungan Ulang Beban Pendinginan pada Ruang Auditorium Gedung Manggala Wanabakti Blok III Kementerian Kehutanan Jakarta

Ruang Auditorium Gedung Manggala Wanabakti diresmikan sejak 24 Agustus 1983 yang merupakan salah satu ruang yang multifungsi diantaranya sebagai ruang rapat/kongres, seminar, wisuda, pameran dan pegelaran, serta resepsi pernikahan. Perhitungan beban pendinginan pada gedung ini menggunakan metode CLTD (Cooling Load Temperature Difference). Perhitungan beban pendinginan berdasarkan data sekunder yang kemudian hasilnya dibandingkan dengan kapasitas beban pendinginan terpasang. Dari hasil perhitungan beban pendingin di atas dapat disimpulkan bahwa kapasitas mesin AHU (Air Handling Unit) yang terpasang belum mencukupi dalam memenuhi kebutuhan sistem penyegaran udara pada ruang Auditorium Gedung Manggala Wanabhakti Kementerian Kehutanan RI

Cyclopentyl Trisilanol Silsesquioxanes – Modified Natural Rubber (CpSSQ(OH)3 – ENR-50) Nanocomposite In The Presence Of Tin (II) Chloride Dihydrate

A nanocomposite comprising cyclopentyl trisilanol silsesquioxanes (CpSSQ(OH)3) and 50% epoxidized natural rubber (ENR-50) was prepared at reflux temperature with Tin (II) chloride dihydrate (SnCl2.2H2O) as catalyst. SnCl2.2H2O was found to be an affective catalyst to promote ring opening in ENR-50 and tailored it to CpSSQ(OH)3 via chemical reaction. The generation of carbonyl functional groups arising from epoxide ring opening can be clearly seen in FTIR spectra. 1H and 29Si NMR analyses further proved that the incorporation of CpSSQ(OH)3 in ENR-50 occured. TGA studies showed a degradation temperature with 10% weight decreased and DSC thermogram indicates a single Tg. Single peak in XRD diffractogram at 2-Theta angle further confirmed the surface modification