Risalah Fisika最新文献

{"title":"Studi Difraksi Sinar-X Struktur Nano Seng Oksida (ZnO)","authors":"Suhufa Alfarisa, Dwi Ahmad Rifai, Parmin lumban Toruan","doi":"10.35895/RF.V2I2.114","DOIUrl":"https://doi.org/10.35895/RF.V2I2.114","url":null,"abstract":"Abstrak – Kajian terhadap difraksi sinar-X struktur nano ZnO dengan waktu sonikasi yang berbeda telah dilakukan menggunakan metode hidrotermal-sonokimia. Variasi waktu sonikasi yang digunakan dalam kajian ini adalah 0 (tanpa sonikasi), 30, 45, dan 60 menit. Pola difraksi sinar-X diplotkan dan dibandingkan untuk mengetahui struktur, kristalinitas dan kemurnian ZnO yang dihasilkan. Estimasi ukuran kristal ZnO juga dihitung menggunakan persamaan Scherrer. Hasil penelitian menunjukkan bahwa struktur nano ZnO yang disintesis tanpa proses sonikasi memiliki kemurnian kristal yang rendah dengan ukuran kristal yang sedang berkisar dari 22,36 – 32,90 nm. Proses sonikasi telah menyebabkan kristalinitas dan kemurnian ZnO meningkat jadi lebih baik. Namun, memperpanjang waktu sonikasi hingga 45 sampai 60 menit menyebabkan membesarnya ukuran kristal ZnO. Waktu sonikasi yang paling optimal adalah 30 menit dimana mampu menghasilkan ZnO dengan kristalinitas dan kemurnian yang baik dan rentang ukuran kristal ZnO yang lebih kecil antara 22,09 – 21,97 nm.                                                                                   Kata kunci: difraksi sinar-X, struktur nano, ZnO, sonikasi, Scherrer Abstract – Research on the X-ray diffraction study of ZnO nanotructure synthesized at different sonication times has been done using hydrothermal-sonochemical method. Sonication variation times that were used in this study were 0 (without sonication), 30, 45, and 60 minutes. The X-ray diffraction patterns were plotted and compared to understand the structure, crystallinity and purity of the resulted ZnO. The estimated crystallite size of ZnO nanostructure were also calculated using Scherrer equation. The results showed that the ZnO nanostructure synthesized without sonication process has a low crystal purity and a fair crystallite size in the range of 22.36 - 32.90 nm. Sonication process has led to a better crystallinity and purity of ZnO. However, longer sonication times up to 45 to 60 minutes has caused to the larger crystal size of ZnO. The most optimum sonication time was found to be 30 minutes which resulted in a good crstallinity and purity of ZnO and smaller crystallite size in the range of 22.09 – 31.97 nm.Key words: X-ray diffraction, nanostructures, ZnO, sonication, Scherrer","PeriodicalId":439956,"journal":{"name":"Risalah Fisika","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125655092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pengaruh Suhu dan Tekanan Udara Lingkungan Terhadap Visibilitas Fatamorgana di Landasan Pacu (Runway) Bandara Sultan Iskandar Muda, Blang Bintang, Aceh Besar, Aceh, Indonesia","authors":"Tjoet Nia Usmawanda, Nasrullah Idris","doi":"10.35895/RF.V2I2.108","DOIUrl":"https://doi.org/10.35895/RF.V2I2.108","url":null,"abstract":"Abstrak – Telah dilakukan sebuah studi mengenai hubungan suhu dan tekanan udara lingkungan landasan pacu (runway) bandara terhadap visibilitas fatamorgana. Pengamatan fatamorgana dilakukan di landasan pacu Bandara Sultan Iskandar Muda (SIM) yang berlokasi di Blang Bintang, Aceh Besar, Aceh, Indonesia. Waktu pengamatan kemunculan dan kehilangan fatamorgana adalah mulai dari sejak matahari terbit pada pagi hari hingga terbenam pada sore hari, yaitu mulai dari jam 07.00 WIB sampai 18.00 WIB dan dicatat tingkat visibilitasnya. Data suhu dan tekanan udara lingkungan didapatkan dari basis data yang dikumpulkan oleh Stasiun Meteorologi Blang Bintang, Aceh Besar, Aceh, Indonesia. Hasil pengamatan menunjukkan bahwa pada saat cuaca cerah, fatamorgana telah muncul sejak matahari terbit dan terus menyebar dari jam 07.00 WIB sampai 13.00 WIB hingga mencapai keadaan paling tebal pada jam 13.00 WIB-15.00 WIB. Selanjutnya fatamorgana mengalami sedikit penyusutan pada jam 15.00 WIB-18.00 WIB, namun demikian masih tampak hingga matahari terbenam. Fatamorgana dapat hilang total bila hujan turun dengan cukup lebat. Sedangkan pada saat cuaca mendung atau gerimis, fatamorgana masih dapat diamati dengan jelas. Suhu terendah dimana fatamorgana masih dapat diamati adalah 26 ºC. Hasil pengamatan tersebut menunjukkan bahwa perubahan suhu dan tekanan udara  rata-rata di lingkungan landasan pacu dapat mempengaruhi visibilitas fenomena fatamorgana melalui pengaruhnya pada gradien suhu udara di atas permukaan landasan pacu tersebut. Densitas udara lingkungan berbanding lurus terhadap suhu dan berbanding terbalik terhadap tekanan. Semakin tinggi densitas udara lingkungan, semakin tipis fatamorgana yang terlihat. Semakin rendah densitas udara lingkungan, maka fatamorgana yang muncul semakin tebal. Hal ini menunjukkan bahwa suhu dan tekanan udara lingkungan adalah parameter yang baik yang menggambarkan visibilitas fatamorgana. Dengan demikian profil suhu dan tekanan udara lingkungan landasan pacu dapat diketahui melalui pengamatan fatamorgana pada landasan pacu bandara.Kata kunci: fatamorgana, visibilitas, suhu, tekanan, indeks bias udaraAbstract – A study about the relationship of the temperature and pressure of the surrounding air in the airpot runway to the visibility mirage was done. The location for the mirage observation is in Sultan Iskandar Muda (SIM) airport runway, located in Blang Bintang District, Aceh, Indonesia. Observation time of the mirage appearance and disappereance is started from sunrise to sunset, namely from 7.00 AM at the morning to 6.00 PM at the evening, and recorded its visibility level. Data for the air surrounding temperature and pressure used was taken from the database of the Blang Bintang Meteorological Station, located in the airport. The results show that during a sunny weather, mirage emerges since sunrise and continues to spread from 7.00 AM to 1.00 PM reaching the thickest level at 1.00 PM till 3.00 PM. The mirage then experiences a slight shr","PeriodicalId":439956,"journal":{"name":"Risalah Fisika","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128533916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efek Circular Dichroism pada Metamaterial Chiral Planar","authors":"Juliasih Partini","doi":"10.35895/rf.v2i2.113","DOIUrl":"https://doi.org/10.35895/rf.v2i2.113","url":null,"abstract":"Abstrak – Penelitian ini mengkaji efek circular dichroism pada metamaterial chiral planar. Bidang polarisasi akan terotasi ketika cahaya yang terpolarisasi linear melewati metamaterial chiral planar. Pada efek circular dichroism, cahaya yang terpolarisasi circular putaran kanan dan putaran kiri akan mempunyai perbedaan absorpsi dalam interaksinya dengan partikel penyusun metamaterial chiral planar. Spektrum eliptisitas metamaterial chiral planar menunjukkan eliptisitas bahan yang bernilai positif untuk sampel putar kanan dan bernilai negatif untuk sampel putar kiri. Nilai eliptisitas diperoleh sebesar maksimal +0,3 dan -0,3 terjadi pada frekuensi 1,29 THz. Eliptisitas maksimum menunjukkan adanya kopling antara foton dengan plasmon permukaan sampel. Polaritas yang berlawanan menunjukkan perbedaan absorbansi antara sampel putar kanan dan sampel putar kiri. Hasil tersebut juga menunjukkan adanya perubahan polarisasi linear pada laser femtosekon menjadi polarisasi eliptik pada  gelombang THz hasil emisi sampel metamaterial chiral planar. Kemampuan metamaterial chiral planar dalam memutar bidang polarisasi dan merubah menjadi polarisasi circular menjadikan bahan ini layak dijadikan alternatif polarisator dalam ranah terahertz.  Kata kunci: metamaterial, circular dichroism, chirality, polarisasi, eliptisitasAbstract – This paper describes the circular dichroism effect on planar chiral metamaterial. When a linearly polarized light passes through the planar chiral metamaterial, its polarization plane will rotate. On the circular dichroism effect, the right and left circulary polarized light will have different absorption due to its interaction with a planar chiral metamaterial. The ellipticity spectrum of a planar chiral metamaterial sample shows a positive ellipticity value for the counter clock-wise sample and a negative value for the clock-wise sample. The maximum ellipticity value is determine as +0,3 and -0,3 at frequency of 1,29 THz. The values show the existence of a coupling between photon and the sample surface plasmon. The opposite polarity indicates that the clock-wise and the counter clock-wise sample have different absorbance. The determined ellipticity value also reveals that the linearly polarized femtosecond laser light has transformed to elliptical polarized THz wave on a planar chiral metamaterial sample emission. The planar chiral metamaterial capability to rotate the polarization plane into circulary polarized wave, makes the material can be considered as an alternative polarizer in terahertz field.  Key words: metamaterial, circular dichroism, chirality, polarization, ellipticity","PeriodicalId":439956,"journal":{"name":"Risalah Fisika","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114156434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mini Roller Coaster (Miroco) sebagai Media untuk Menghitung Percepatan Ditinjau dari Energi Mekanik","authors":"Sony Yunior Erlangga, Handoyo Saputro","doi":"10.35895/rf.v2i2.80","DOIUrl":"https://doi.org/10.35895/rf.v2i2.80","url":null,"abstract":"Abstrak – Telah dibuat alat Mini Roller Coaster (Miroco) untuk percobaan dalam menghitung percepatan ditinjau dari energi mekaniknya. Alat dan bahan yang digunakan pipa besi, plat besi, aluminium foil dan mobil lego sebagai benda yang dapat divariasi massanya. Miroco sebagai media dalam menjelaskan konsep percepatan dan gaya gesek pada benda dengan memvariasi massa ditinjau dari energi mekanik. Dengan alat ini diharapkan dapat mengatasi miskonsepsi pada peserta didik dalam pokok bahasan usaha dan energi. Penelitian ini mengunakan metode ekperimen. Diperoleh hasil bahwa besarnya massa benda mempengaruhi energi kinetik yang menyebabkan penurunan percepatan pada benda. Hal tersebut terjadi karena lintasan kasar sehingga mengakibatkan besarnya massa benda mempengaruhi nilai gaya gesek antar kedua bidang yang bergesekan. Semakin besar massa suatu benda semakin berkurang percepatannya dan sebaliknya. Percobaan yang kami lakukan memiliki tingkat ketelitian rata-rata sebesar 99,76%.  Kata kunci: energi mekanik, gaya gesek, media, miroco, percepatanAbstract – The research has created a Mini Roller Coaster (Miroco) for the experiment in calculating the acceleration as seen from the mechanical energy. Tools and materials used were iron pipes, iron plates, aluminum foil and car legos as objects of varying mass.  Miroco as the media in explaining the concept of acceleration and friction on objects with varying mass as viewed from mechanical energy. By using this, the students’ misconceptions in the subject of force and energy were expected to be overcome. This study uses an experimental method. The results obtained show that the mass of the object affects the kinetic energy which causes a decrease in acceleration on the objects. This happens because of rough trajectory causing the magnitude of the mass of the object affects the value of the friction force between the contact planes. The greater the mass of an object on trial of the Miroco, the greater it reduced acceleration or vice versa. In the experiments done have an average accuracy of  99.76%. Key words: mechanical energy, friction, media, miroco, acceleration","PeriodicalId":439956,"journal":{"name":"Risalah Fisika","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114873627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}