Judul: Pemanfaatan Frekuensi Bunyi untuk Menduga Kadar Air dan Vigor Benih Jagung (Zea mays L.)
Abstrak: Seed lots in different condition were needed as material of this sound detection research. The goal of this research is learning about utilization of sound frequency to expect moisture content and vigour of the corn seed. This research was conducted at Seed Science and Technology Laboratory, Bogor Agricultural University and Spectroschopy Laboratory, Bogor Agricultural University from February 2013 to June 2013. The experiment was arranged in complete randomized design with two factors and three replications. This research divided in two experiments, (1) correlation between variety and seed moisture content and (2) correlation between variety and seed vigour about its frequencies output. Seed size definited by its 1 000 granule mass, Srikandi Putih variety is used for big size, Bisma is used for medium size and SD-III is used for small size. Several moisture content levels are got by closed moisturizing process. Seed lots with three different vigor levels are got by physical accelerating method, used oven in 40-45 °C and high moisture condition. After gave the preface treatment, the seed lots got the sound detection testing. The result showed in the first experiment, variety could give effect to the frequency output. The second experiment gave result that variety, vigour level and interaction of both didn’t give effect to the frequency output. Sound frequency cannot be used to expect moisture content and vigour of corn seed, but sound frequency can be used as variety marker.
Keyword: 

Judul: Development of Non-Destructive Quality Testing of Corn (Zea mays) Seeds Using Acoustic Methods
Abstrak: Pengujian mutu benih dapat dilakukan secara langsung dan tidak langsung. Pengujian mutu secara tidak langsung dapat dilakukan menggunakan metode akustik (gelombang berdiri) dengan mengukur kemampuan benih menyerap gelombang bunyi. Penelitian ini bertujuan mengembangkan metode tidak langsung dan nondestruktif pengujian mutu vigor dan kadar air (KA) benih jagung berdasarkan absorpsi gelombang bunyi menggunakan metode gelombang berdiri. Penelitian dilaksanakan pada bulan Januari˗Maret 2023 di Laboratorium Penyimpanan dan Pengujian Benih dan Laboratorium Fisika Lanjut, IPB Dramaga, Jawa Barat. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) faktor tunggal. Percobaan pertama dilakukan untuk memilih kombinasi jumlah benih (90; 120; 150 butir) dan 10 frekuensi (1275-5100 Hz, kelipatan 425 Hz) terbaik berdasarkan nilai koefisien absorpsi benih sebagai acuan percobaan selanjutnya. Percobaan kedua dilakukan dengan mengkombinasikan faktor KA (8,7%; 12,1%; dan 13,8%) dan frekuensi terpilih. Percobaan ketiga dilakukan dengan mengkombinasikan frekuensi terpilih dan tingkat vigor benih yang diperoleh dari pengusangan cepat. Hasil menunjukkan bahwa kombinasi 150 butir dan frekuensi terpilih 3400; 3825; 4250 Hz merupakan hasil terbaik untuk digunakan pada percobaan selanjutnya. Metode gelombang berdiri dapat membedakan tingkat KA 8,7% dan 13,8%, serta membedakan tingkat vigor benih jagung dengan tolok ukur radicle emergence pada frekuensi 3825 Hz. Metode tersebut dipengaruhi oleh ketebalan, densitas, dan susunan posisi benih., Seed quality testing can be conducted through direct and indirect methods. The indirect method can be conducted by acoustic methods (standing wave) which measures the sound wave absorption capacity of seeds. This study aimed to develop an indirect and non-destructive method for testing the quality of vigor and moisture content (MC) of corn seeds based on the absorption of sound waves using the standing wave method. The research was conducted from January to March 2023 at the Seed Storage and Testing Laboratory and Advanced Physics Laboratory, IPB Dramaga, West Java. This study used a single factor, Completely Randomized Design (CRD). The first experiment was conducted to choose the best combination of seed bulk (90; 120; 150 seeds) and 10 frequencies (1275-5100 Hz, the multiple of 425 Hz) based on the seed absorption coefficient to be used for the next experiments. The second experiment was carried out with the combination of MC (8.7%; 12.1%; 13.8%) and chosen frequencies. The third experiment was conducted within the combination of chosen frequencies and seed vigor levels obtained from accelerated aging. The result showed that the combination of 150 seeds and 3400; 3825; and 4250 Hz of chosen frequencies was the best result to be used for further experiments. The standing wave method could distinguish between 8.7% and 13.8% of MC levels, and distinguish the vigor level of corn seeds with the radicle emergence benchmark at 3825 Hz of frequency. This method is influenced by the thickness, density, and the formation of seed bulk
Keyword: 

Judul: Solusi Geometri Schwarzschild untuk Dimensi 4+1 dengan Invarian Rotasi Isotropik.
Abstrak: Metrik Schwarzschild merupakan solusi eksak pertama dari persamaan medan Einstein dengan mangasumsikan metrik statik dan simetris. Metrik Schwarzschild yang ditemukan oleh Karl Schwarzschild masih dalam dimensi 3+1, namun seiring dengan teori-teori terbaru yang menunjukkan bahwa alam semesta tidak hanya di dimensi 3+1. Maka melalui penambahan dimensi, tujuan penelitian ini memperoleh solusi pada geometri Schwarzschild untuk dimensi 4+1 dengan memodifikasi koordinat bola yang invarian rotasi isotropik dan melalui penurunan rumus seperti koordinat bola, simbol Christoffel, dan tensor Ricci. Selain mendapatkan solusi ini, metrik Schwarzschild dimensi 4+1 dapat digunakan sebagai metrik dasar untuk memperoleh solusi blackhole dan wormhole pada dimensi 4+1. Hasil akhirnya, dengan memanfaatkan modifikasi koordinat bola, metrik Schwarzschild dapat dibentuk sehingga diperoleh solusi geometri Schwarzschild untuk dimensi 4+1.
Keyword: metrik Schwarzschild, persamaan medan Einstein, modifikasi koordinat bola, penambahan dimensi, invarian rotasi isotropik