Judul: Sifat Fisikokimia, Termal, dan Spektroskopi Selulosa Mikrokristalin Serabut Ampas Sagu
Abstrak: Microcrystalline cellulose (MCC) is a partially depolymerized from α-cellulose. MCC is generally used as a medicinal preparation. MCC isolates from sago waste fiber and commercial MCC (MCCK) were characterized based on physicochemical, thermal, and spectroscopic properties. MCC1 was isolated through hydrolysis, pulping, and bleaching stages while MCC2 was isolated by pulping, bleaching, and hydrolysis steps, respectively MCC1 and MCC2 yields were 13% and 6.5% with α-cellulose levels of 78.61% and 73.08%. Physicochemical properties results of all three MCCs were in accordance with MCC’s standard. MCC1 and MCCK had degree of polymerizations fulfilling MCC’s standard (􀵑���350) while for MCC2, the value was over 700. Infrared spectra of MCC1 and MCCK were also in accordance with MCC’s standard, whereas the MCC2 spectrum still showed the presence of lignin. Based on thermal analysis, MCC2 had the highest degradation temperature and degree of crystallinity, which were 396.26 °C and 66.4%, respectively, corresponding to the high lignin content. MCC1 had the largest surface area, enable to bind more active ingredient medicine.
Keyword: cellulose, microcrystalline, sago

Judul: Modifikasi Sintesis dan Pencirian Fase Diam Kromatografi Kolom Selulosa Berbasis Serabut Ampas Sagu.
Abstrak: Grafting copolymerization of acrylamide (AAm) on cellulose derived from sago fibers (α-cellulose 78.61%) has been performed by using N,N'-methylene-bis-acrylamide (MBA) as cross-linker and ammonium peroxydisulfate as initiator. The cellulose-g-polyacrylamide copolymer products were characterized by their water absorption capacity, grafting ratio, and grafting efficiency as the initial characterizations. Further characterizations was carried out by using infrared spectroscopy, electron microscopy imaging, and X-ray diffraction techniques. The characterization results showed that the copolymers has been formed. Synthesis modification by sequential addition of AAm and MBA, and increased concentration of MBA reduced the water absorption capacity, whereas the grafting ratio and efficiency were increased. Copolymer products could be applied as a stationary phase for normal-phase column chromatography, based on the porous surface morphology as well as good resistance against n-hexane, n-pentane, and cyclohexane solvents.
Keyword: sago fibers, grafting, copolymerization, cellulose, acrylamide

Judul: Zero-inflated negative binomial models in small area estimation.
Abstrak: The problem of over-dispersion in Poisson data is usually solved by introducing prior distributions which lead to negative binomial models. Poisson data sometime is also suffered by excess zero problems, a condition when data contains too many zero or exceeds the distribution's expectation. Zero Inflated Negative Binomial (ZINB) method can be utilized to solve such problems. This paper demonstrates the adaption of ZINB methods in Small Area Estimation with excess zero data. It is shown that the excess zero problem has substantially influenced the Empirical Bayes (EB) estimates, and the adaption of ZINB methods has improved the precision and reliability of the estimates. Key Words: Small Area Estimation, Zero-Inflation, Poisson-Gamma, Negative Binomial Regression, Empirical Bayes
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