Judul: Pengaruh takaran zeolit dan pupuk urea serta masa inkubasi terhadap ketersediaan NH4, Mg2, Ca2, Na dan perubahan pH regosol Ciomas
Abstrak: Penelitian ini bertujuan untuk melihat dan mempelaja- ri pengaruh dari pemberian zeolit dan pupuk urea masa serta inkubasi terhadap ketersediaan amonium, magnesium, kalsium, natrium dan perubahan pH tanah pada Regosol Ciomas. Percobaan dilakukan dengan mempergunakan tanah dan zeolit. Takaran zeolit yang diberikan adalah 0,5%, 10%, 20% dan 100% dan untuk urea adalah 0, 100 ppm N dan 200 ppm N. Analisis jumlah amonium dan basa-basa yang dapat dipertukarkan serta pH tanah dilakukan pada masa inkubasi 0,5 hari, 10 hari, 15 hari dan 20 hari. Masing-masing perlakuan diinkubasikan di dalam rumah kaca dan dilakukan penyiraman untuk menjaga kelembaban tanah agar tetap dalam keadaan kapasitas lapang. Analisis NH4+, Mg2+, Ca2+ dan Nat dilakukan dengan metode ektraksi dengan KCl 1 N (pH 1.5 dengan HCl) dan pengocokkan selama 16 jam. Untuk pH tanah dilakukan dengan perbandingan 1 1, diukur dengan pH-meter. ..
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Judul: Pengaruh pemberian takaran mineral zeloit dengan lamanya waktu inkubasi terhadap perubahan titik muatan nol (pHo) dan beberapa sifat kimia tanah oxisol dari pelaihari (Kalimantan Selatan)
Abstrak: Penelitian ini bertujuan untuk mengatahui pengaruh pemberian mineral zeolit dengan perbedaan lamanya waktu inkubasi terhadap perubahan titik muatan nol (pH) tanah dan perubanan beberapa sifat kimia tanah, antara lain: kemasaman tanah, kapasitas tukar kation, dan kadar bebera- pa unsur nara, seperti K-dd, Na-dd, Ca-ad, dan Mg-dd, serta terhadap alumunium yang dapat dipertukarkan. Penelitian dilakukan mulai awal Desember 1988 sampai akhir Juni 1969. Tempat yang digunakan adalah Rumah Kaca, Laboratorium Mineralogi, Laboratorium Kimia Jurusan Tanah, aan Laboratorium Agronomi Balitan Cimanggu, Bogor. Tanah diambil secara komposit dari lapangan kemudian dikering udarakan, ditumbuk dan diayak dengan ayakan 2mm. Selan- jutnya ditimbang sebanyak 500 g (BKM) dimasukkan ke dalam polibag serta ditambahkan mineral zeolit yang telan diak- tifkan sesuai dengan takaran yang ditentukan. Takaran mineral zeolit yang dicobakan adalah 0, 2, 4, 8, aan 16 ton per hektar. Langkah selanjutnya diinkubasi selama 3b dan 12 minggu dalam keadaan kapasitas lapang. Pada akhir masa inkubasi contoh tanah diambil kemudian dianalisis untuk ditentukan sirat kimianya. Pemberian mineral zeolit berpengaruh terhadap penurunan titik muatan nol (pH) tanah, serta peningkatan beberapa sitat kimia tanah, seperti pH tanah, kapasitas tukar kation, kadar K-da, Na-dd, dan Ca-ad. Pemberian takaran mineral zeolit berpengaruh nyata terhadap peningkatan pH tanah, KTK, dan sangat nyata terhadap K, Na, dan Ca yang dapat dipertukarkan. Takaran yang memberikan nilai hasil analisis tertinggi adalah 6 ton per hektar atau berkisar antara 4 dan 8 ton per hektar…dst
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Judul: Algorithm Construction of HLI Hash Function
Abstrak: Cryptography is a study of mathematical techniques related to aspects of information security regarding on confidentiality, data integrity, entity authentication, and data origin authentication. Data integrity is a service, which is associated with the conversion of data carried out by unauthorized parties. To maintain data integrity, one can use hash functions. An hash function is a computationally efficient function to map an arbitrary length bitstring to a fixed length bitstring called as hash value. The use of hash function in maintaining the information integrity and authentication is in digital signatures, virus protection, and software distribution. Illustration of the hash function in the integrity and authentication of information that is emailed as follow. The sender sends the information and hash value to the recipient. If the hash value of the information is equal to the hash value that is sent by the sender, then information has not been changed. Otherwise the information has been changed. An hash function has two properties, one way and collision resistance. An hash function is called one way if it is computationally infeasible to find any input such that when given any hash value . Meanwhile an hash function is called collision resistant if it is computationally infeasible to find any two inputs where such that . The purpose of this study is to construct a HLI hash function algorithm, to analyze the speed and security of the hash functions as a results of construction. Furthermore, it is to compare it with SWIFFT. Hash function is constructed based on the result of algebraic operations on modular polynomial ringwith . Modular polynomial ring noted as is a set of all polynomials of degree at most with coefficients in . can be represented as a set of integer vector of modulo in dimension . So, it is simple to implement in a computer. In vector operations, is lattice . Furthermore, alattice that is defined from certain polynomial ring is called ideal lattice. HLI hash function is consists of addition and multiplication algorithm in the ring. Addition algorithm consists of sumation operations of modulo and multiplication consists of multiplication operations of modulo . Generally, algorithm of HLI hash function consists of multiplication operations of modulo and addition operations of modulo . However, if the input is binary number then multiplication algorithm only consists of multiplication operation of modulo , so algorithm of HLI hash function consists of multiplication operations of modulo and addtion operations of modulo . An hash function is secured if it has two properties, i.e., one way and collision resistance. HLI hash function hash is one way, it is following the proof of Micciancio. It is has collision resistant because of polynomial is irreducible over and monic. Moreover, it is proved that for every unit vector , the vector is small vector. If the input of hash function is a binary number then HLI hash function only involves addition operations of modulo . So the time that used almost same with SWIFFT. The excellence of HLI hash function is the key size smaller than SWIFFT. This effect on
Keyword: hash function, modular polynomial ring, lattice