Judul: Ekstraksi Silikon Dioksida dari Abu Jerami Padi.
Abstrak: Jerami padi merupakan salah satu limbah terbesar dari bagian tanaman padi, biasanya limbah jerami padi hanya dibakar saja setelah proses panen oleh petani, padahal jerami padi mengandung senyawa anorganik utama yaitu silikon dioksida sebesar 75%. Ekstraksi silikon dioksida salah satunya dipengaruhi oleh suhu pengabuan. Variasi suhu yang digunakan pada penelitian ini yaitu 700 °C, 800 °C dan 900 °C. Semua proses ekstraksi dengan 3 variasi suhu pengabuan ini sama mulai dari pembakaran jerami dengan korek api, pencucian menggunakan HCl 3% teknis dan pembilasan menggunakan aquades dengan suhu 105 °C. Proses yang berbeda adalah proses pengabuan dalam furnace dengan set up suhu yang berbeda. Silikon dioksida dengan suhu pengabuan 700 °C memiliki rentang nilai konduktivitas listrik dari frekuensi 50 Hz sampai 5 MHz berupa semikonduktor, silikon dioksida dengan suhu pengabuan 800 °C memiliki rentang nilai konduktivitas listrik dari frekuensi 10.245 kHz sampai 5 MHz berupa semikonduktor dan silikon dioksida dengan suhu pengabuan 900°C memiliki rentang nilai konduktivitas listrik dari frekuensi 11.502 kHz sampai 5 MHz berupa semikonduktor. Silikon dioksida dengan suhu pengabuan 700 °C, 800 °C dan 900 °C memiliki kemurnian berturut-turut yaitu 80.97% atom; 99.99% atom; 61.53% atom. Silikon dioksida dengan suhu pengabuan 700 °C, 800 °C dan 900 °C memilki derajat kristalinitas berturut-turut yaitu 25.819%, 44.24% dan 45.608%.
Keyword: extraction, ignition, purity, rice straw, silicon dioxide

Judul: Pengembangan Ekstraksi Silikon Sekam Padi untuk Semikonduktor
Abstrak: Indonesia is a country with rich natural resources. One of the natural resources in this country is a waste rice husk. Waste rice husk contains silica which is used as raw material for producing silicon. This study aims to obtain silica for use as a producer of silicon materials. Rice husk waste contains 39.04% of silicon. Rice husk is burnt with the variation rate of temperature rise in 1, 3, 5, and 7 ° C / min. Ash content with fewer impurities found in the burning rate of rise of temperature of 1 ° C / min. The ash then washed and made the process of mixing with the variation at 300, 400, 500, and 600 rpm. Silica is processed at a speed of 600 rpm, then burned at a pace of temperature 1 ° C / min resulted in purity silica (SiO2) at 99% and 0.22% silicon has been formed. Silica which has been obtained then reducted using Magnesium (Mg) in the combustion temperature of 650 ° C. silicon obtained by EDS (energy dispersive X-ray) analysis still contained impurities Magnesium. This result is not up to the necessary levels of percentage of silicon.
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Judul: Quantitative Trait Loci Mapping for Trait in Categorical Scale
Abstrak: Genes or regions on chromosome underlying a quantitative trait are called Quantitative Trait Loci (QTL). Characterizing genes controlling quantitative trait on their position in chromosome and their effect on trait is through a process called QTL mapping. In estimating the QTL position and its effect, QTL mapping basically utilize the association between QTL and DNA markers. However, many important traits are obtained in categorical scale, such as resistance from certain disease. From a theoretical point of view, QTL mapping method assuming continuous trait could not be applied to categorical trait. This research was focusing on the assessment of the performance of Maximum Likelihood (ML) and Regression (REG) approach employed in QTL mapping as well as the performance of Lander and Botstein (LB) and Piepho method in determining critical value in testing the existence of QTL for binary and ordinal trait by means of simulation study. The simulation study to evaluate the performance of ML and REG approach was conducted by taking into account several factors that may affecting the performance of both approaches. The factors are: (1) marker density; (2) QTL effect; (3) sample size; (4) shape of phenotypic distribution; (5) number of categories; and (6) number of QTL. Moreover, the simulation study for evaluating LB and Piepho method in determining critical value was conducted by generating distribution of the test statistic under null hypothesis. From simulation study, it was obtained that LB and Piepho method showing similar performance in determining critical value in testing the existence of QTL for binary and ordinal trait. The simulation study also indicating that both methods could be used in determining critical value in QTL mapping analysis for binary trait as well as for ordinal trait if the REG approach is used but not if ML approach is used due to their poor performance. In assessing the performance of ML and REG approach in QTL mapping analysis for binary trait, the two approaches showing comparable performance; whereas for ordinal trait REG approach showing poor performance compared with ML approach in estimating thresholds. As a result, in QTL mapping analysis, ML and REG approach could be used when dealing with binary trait, whereas ML approach is suggested when dealing with ordinal trait.
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