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6 results on '"Arni Pratiwi"'

1. PENGARUH MUTU MORTAR DAN DIMENSI INKLUSI TERHADAP KUAT TEKAN MORTAR-INKLUSI

Author

Purwanto Purwanto, Himawan Indarto, Yulita Arni Pratiwi, Nauval Rabbani, and Mona Dwi Anggraeni

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

Kuat tekan beton sangat dipengaruhi oleh material penyusunnya, perilaku saat pencampurannya, perawatannya, dan kekuatan hubungan lekatan yang terjadi antara permukaan agregat kasar dengan mortar atau yang disebut Interfacial Iransition Zone (ITZ). Penelitian menunjukkan bahwa rasio kuat tekan inklusi agregat terhadap kuat tekan mortar sangat signifikan mempengaruhi perilaku ITZ dan keseluruhan benda uji. Namun sejauh ini penelitian difokuskan pada inklusi batuan, sedangkan perilaku ITZ dengan inklusi baja belum banyak dilakukan. Baja mempunyai sifat relatif lebih homogen dan stabil, tak memiliki retak mikro serta tak menyerap air, sehingga pengaruh mutu mortar pada ITZ akan tampak lebih jelas. Untuk mempelajari perilaku inklusi baja pada benda uji, maka dilakukan studi menggunakan beberapa varian mutu mortar dengan kuat tekan 20, 40, dan 60 MPa. Ukuran benda uji adalah 150×150×50 mm dengan inklusi silinderis besi baja berdiameter 25 mm dan 32 mm. Silinder baja ditempatkan tepat pada pusat berat mortar. Disediakan pula benda uji kontrol berupa mortar tanpa inklusi dengan ukuran 150×150×50 mm untuk dapat membandingkan perilaku pengaruh dari variasi mutu dan variasi diameter inklusi silinder baja. Benda uji diuji dengan pembebanan satu arah (uniaksial) menggunakan Universal Testing Machine (UTM) dan Linear Vertical Displacement Transducer (LVDT) untuk mengetahui perilaku perubahan bentuk sebagai fungsi beban. Hasil analisa menunjukkan bahwa semakin besar diameter inklusi semakin rendah pula kuat tekan yang dihasilkan serta terjadinya pola retak di area inklusi yang merupakan daerah ITZ. Kata kunci: inklusi baja, ITZ, perilaku kuat tekan, pola retak

Published
2018
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2. Unidirectional lasing using loss management in a reciprocal fiber ring laser

Author

Arni Pratiwi, Alexander Hartung, Matthias Jäger, and Muhammad Assad Arshad

Subjects
Materials science, Optics, business.industry, Fiber ring laser, Physics::Optics, Ring laser, A fibers, business, Instability, Lasing threshold, Reciprocal, Power (physics), Term (time)
Abstract

We report on the observation of a new phenomenon, occurring in a fiber ring laser. This phenomenon describes the transition from an initially bidirectional emission of a reciprocal fiber ring laser to a unidirectional emission at a certain pump power threshold. In addition, the final direction is not predefined but appears to be randomly chosen every time the threshold is exceeded. Therefore, we term this new phenomenon as direction instability. In addition we provide a first discussion of how the pump power threshold and the final direction can be influenced by the length and the loss of the cavity.

Published
2021

3. Observation of direction instability in a fiber ring laser

Author

Arni Pratiwi, Matthias Jäger, Muhammad Assad Arshad, and Alexander Hartung

Subjects
Science, Physics::Optics, Ring laser, 02 engineering and technology, 01 natural sciences, Instability, Article, 010309 optics, Optics, Fiber ring laser, 0103 physical sciences, Lasers, LEDs and light sources, Optical materials and structures, Optical techniques, A fibers, Scaling, Physics, Multidisciplinary, business.industry, 021001 nanoscience & nanotechnology, Power (physics), Nonlinear system, Optics and photonics, Medicine, Other photonics, 0210 nano-technology, business
Abstract

We report on the observation of a new phenomenon occurring in a fiber ring laser. This phenomenon is about the transition from an initially bidirectional emission of a reciprocal fiber ring laser to a unidirectional emission at a certain pump power threshold. In addition, the final direction is not predefined but appears to be randomly chosen every time the threshold is exceeded. Therefore, we term this new phenomenon direction instability. Furthermore, we provide a first discussion of how the instability threshold is influenced by the length and the loss of the cavity. We show that the threshold follows a power times length scaling, indicating a nonlinear origin.

Published
2021

4. Influencing direction instability using loss management in a reciprocal all-fiber kilometer-long ring laser

Author

Arni Pratiwi, Matthias Jäger, Muhammad Assad Arshad, and Alexander Hartung

Subjects
Materials science, Mathematics::Commutative Algebra, business.industry, food and beverages, Physics::Optics, Ring laser, Ring (chemistry), Instability, Optics, All fiber, Fiber laser, business, Lasing threshold, Computer Science::Databases, Reciprocal
Abstract

Recently we demonstrated unidirectional lasing in a reciprocal all fiber ring laser. The phenomenon is threshold dependent and both the final direction and threshold can be influenced through loss management of the ring.

Published
2021

5. Effect of Fiber Length and Loss on the Threshold of Unidirectional Lasing in a Reciprocal All-Fiber Ring Laser

Author

Muhammad Assad Arshad, Matthias Jäger, Alexander Hartung, and Arni Pratiwi

Subjects
Materials science, All fiber, business.industry, Optoelectronics, Ring laser, Fiber, business, Lasing threshold, Reciprocal
Abstract

We recently demonstrated unidirectional lasing in a reciprocal all fiber ring laser at full laser operation. With this manuscript we discuss the influence of length and fiber loss on the triggering of unidirectional lasing in this fiber ring laser.

Published
2020

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