http://repository.usu.ac.id:80/handle/123456789/15080 2013-05-19T18:02:13Z 2013-05-19T18:02:13Z Aththorick, T. Alief Widhiastuti, Retno Evanius , Ananta  http://repository.usu.ac.id:80/handle/123456789/19753 2010-08-24T07:20:23Z 2010-08-24T00:00:00Z

Authors: Aththorick, T. Alief; Widhiastuti, Retno; Evanius , Ananta  Abstract: A study on tree diversity in three zones Sinabung Mountain forest had been conducted using purposive sampling method. Zone I: Sub Mountain Forest (1450-1750) m above sea level (asl), zone II : Transition (1750-2050) m asl, and zone III : Mountain Forest (2050 – 2200) m asl. Plots size was settled 10 by 200 m ( 0,2 ha) for each zone. The result showed that in the whole zones there were 276 individual trees of 93 species of 33 families. Tree was dominated by Theaceae, Myrtaceae, Fagaceae, Rubiaceae, Ericaceae, and Lauraceae. Zone I had 84 individuals of 44 species of 16 families was dominated by Lithocarpus indutus. Zone II was dominated by Symingtonia populnea, had 119 individuals of 43 species of 23 families, while zone III was dominated by Gordonia imbricate had 73 individuals of 15 species of 9 families. Diversity indexes of location I, II and III were high relatively with values of 3.525, 3.312 and 2.148, respectively.

2010-08-24T00:00:00Z Aththorick, T. Alief Widhiastuti, Retno Evanius , Ananta  Muhdi http://repository.usu.ac.id:80/handle/123456789/19752 2010-08-24T07:14:39Z 2010-08-24T00:00:00Z

Authors: Muhdi Abstract: The objectives of this research were to know residual stand damage and opened areas caused by conventional and reduced impact timber harvesting (RITH) in natural forest. This research show that the degree of residual stand damages based on tree population and stage of vegetation development in conventional timber harvesting and reduced impact timber harvesting was as follow : for seedlings 34.42 % and 23.17 %, for saplings 35.13 % and 21.72 %, for poles and trees 33.15 % and 19.53 %. The degree of opened caused by conventional timber harvesting was 32.47 % compared with reduced impact timber harvesting which is only 18.32 %. The research result indicated that that felling and skidding by reduced impact timber harvesting can diminish by up to 43 % the opened timberland otherwise caused by conventional timber harvesting.

2010-08-24T00:00:00Z Muhdi Surbakti, Mariana Br http://repository.usu.ac.id:80/handle/123456789/19751 2010-08-24T07:08:48Z 2010-08-24T00:00:00Z

Authors: Surbakti, Mariana Br Advisors: Ginting, Mimpin; Sihotang, Herlince; Ginting, Keling Abstract: 1, 9 Nonanil diglucosamide, has been synthesized by amidation of gluconic acid with 1,9 nonane diamine with 58%. 1,9 Nonanil diglucosamide is a surfactant with HLB of 3,25.Each step of reaction cas characterized by spectroscopic FT-IR and 1 H NMR.

2010-08-24T00:00:00Z Surbakti, Mariana Br Ginting, Mimpin Sihotang, Herlince Ginting, Keling  http://repository.usu.ac.id:80/handle/123456789/19750 2010-08-24T07:02:40Z 2010-08-24T00:00:00Z

Authors: Ginting, Mimpin; Sihotang, Herlince; Ginting, Keling  Advisors: Surbakti, Darwis; Sebayang, Abdi Suranta Abstract: Castrol oil can be isolated by extraction from kernel castrol using somes organic solvent. The isolation of castro oil socletation give percentage 49.90 % using 2-propanol as the solvent, 46.00 % using ethanol as the solven and 17.00% using n-hexana as the solvent. Ricinoleic has been found as triglyceride in castrol oil can be dehydrated by refluks using moleculer shieve i somes organic solvent to result linoleic as triglyceride. The product of dehydrated give rendement 82.58% usin ethanol as the solvent, 68.75% using diethyl eter as the solvent, 80.83% using petroleum eter as the solvent an 81.69% using n-hexana as the solvent. The analysis by iodine value give best product using petroleum eter as th solvent where before dehydrated is 85 and after dehydrated 120.4.5 The product of methenolysis of castrol oil and dehydratyed castrol oil is analyzed using FT-IR spectroscopy an GC-MS. Based on the analysis, we get 5-methyl ester fatty acid, which are methyl hexadecanoic 2.88% meth 9,10-octadecadienoic 7.09% methyl 9-octadecadienoic 10.60%, methyl octadecanoic 2.35%, and methyl 12 hydroxy 9-octadecadienoic 77.08%. For the dehydrated castrol oil we get 8 methyl ester fatty acid, which ar methyl hexadecanoic 2.99%, methyl 9.10-octadecadienoic 17.58%, methyl9-octadecadienoic 31.28%, meth octadecanoic 7.08%, methyl 9,10-octadecadienoic (trans) 13.02%, methyl 9-octadecadienoic (trans) 10.74% methyl 12-hydroxy 9-octadecadienoic 10.22% and another fatty acid 7.14%.

2010-08-24T00:00:00Z Ginting, Mimpin Sihotang, Herlince Ginting, Keling  Surbakti, Darwis Sebayang, Abdi Suranta http://repository.usu.ac.id:80/handle/123456789/19749 2010-08-24T06:55:59Z 2010-08-24T00:00:00Z

Authors: Surbakti, Darwis; Sebayang, Abdi Suranta Advisors: Muhdi; Sucipto, T; Widyanti, M Abstract: N-benzoyl glutamide compound can be prepared by amidation benzoyl chloride with glutamic acid. Synthesis the amide used acetone/water solvent system at pH=12.0 through strring condition at 0-10 C. The N-benzoy glutamide product yielded from synthesis reaction was then isolated from reaction mixture user ethyl acetate solvent at pH 2-3 continued with purification step by solvent evaporation, crystallization in diethyl ether solvent to give solid crystal with mp. 135-136OC. Spectra of FT-IR and 1H-NMR have confirmed that the reaction product was in good agreement with the proposed structure. The compound was then assigned the surface tension which was then converted into HLB value using Du-Nuoy ring method and it give the value 5.274.

2010-08-24T00:00:00Z Surbakti, Darwis Sebayang, Abdi Suranta Muhdi Sucipto, T. Widyanti, M. http://repository.usu.ac.id:80/handle/123456789/19748 2010-08-24T06:59:04Z 2010-08-24T00:00:00Z

Authors: Muhdi; Sucipto, T.; Widyanti, M. Abstract: Tujuan yang ingin dicapai dalam penelitian ini adalah untuk mengetahui produktivitas penyaradan kayu dengan traktor Komatsu D70 LE. Hasil penelitian ini menunjukkan bahwa produktivitas penyaradan kayu dengan menggunakan traktor D70 LE sebesar 19,92 m3/jam (di mana rata-rata jarak sarad, volume sarad, dan kemiringan lapangan masing-masing sebesar 368,01 m; 7,47 m3 and 20,02%). Penelitian ini menunjukkan bahwa pengaruh jarak sarad, volume sarad, dan kemiringan lapangan terhadap produktivitas penyaradan kayu dengan menggunakan traktor Komatsu D70 LE didapat persamaan regresi Y = 18,353 + 2,059 (X1) – 0,018 (X2) – 0,365 (X3). Abstract (other language): The objective of this research was to know the productivity skidding by tractor of Komatsu D70 LE. Result of this research indicate that the productivity skidding by tractor of Komatsu D70 LE was 19.92 m3 /jam (the average of skidding distance, log volume and topography were 368.01 m; 7.47 m3 and 20.02 % respectively). The research indicate that the effect of skidding distance, log volume and topography to the productivity of skidding by tractor of Komatsu D70 LE is found that the regression was Y = 18.353 + 2.059 (X1) – 0,018 (X2) – 0.365 (X3).

2010-08-24T00:00:00Z Muhdi Sucipto, T. Widyanti, M. The objective of this research was to know the productivity skidding by tractor of Komatsu D70 LE. Result of this research indicate that the productivity skidding by tractor of Komatsu D70 LE was 19.92 m3 /jam (the average of skidding distance, log volume and topography were 368.01 m; 7.47 m3 and 20.02 % respectively). The research indicate that the effect of skidding distance, log volume and topography to the productivity of skidding by tractor of Komatsu D70 LE is found that the regression was Y = 18.353 + 2.059 (X1) – 0,018 (X2) – 0.365 (X3). Ginting, Armansyah http://repository.usu.ac.id:80/handle/123456789/19747 2010-08-24T06:36:17Z 2010-08-24T00:00:00Z

Authors: Ginting, Armansyah Abstract: From a serial of machining trials that carried out in this study, it was obtained that carbide tool (WC+Co) coated with (TiC/TiAlN/TiN) by PVD method could be used to dry mill titanium alloy Ti-6Al-2Sn-4Zr-2Mo-0.08Si (Ti- 6242S) up to cutting speed (V) of 150 m/min, feeding (f) of 0.15 mm/tooth, axial depth-of-cut (aa) of 2 mm, and radial depth-of-cut (ar) of 8.8 mm. This cutting condition, in particular cutting speed, is 2.5 times higher than the common cutting speed used for cutting titanium alloys (60 m/min). Although under that cutting condition tool life was recorded as short as 1.70 minutes, but the round insert tool type used in this study could be indexed and thus, each insert had 5 cutting edges. As a result, the total tool life can be achieved by each insert tool is 8.5 minutes and this value is higher than the shortest tool life required for cutting of titanium alloys (5 minutes). The cutting conditions (cutting speed and feeding) and tool life are then formulated based on the Taylor model VTn =C dan fTn =C. The lower exponent value (n) in VTn =C model comparing to fTn =C model indicates that tool life is more effected by cutting speed than feeding.

2010-08-24T00:00:00Z Ginting, Armansyah Dalimunthe, Aminah Nainggolan, Marline http://repository.usu.ac.id:80/handle/123456789/19746 2010-08-24T06:31:52Z 2010-08-24T00:00:00Z

Authors: Dalimunthe, Aminah; Nainggolan, Marline Abstract: Extraction and test activity of anti bacteria from etanol extraction of Cocos nucifera Linn for bacteria Eschericia coli and Shigella dysenteriae has been done. Extraction of Cocos nucifera Linn has been treated by maserasi with etanol 80% as solvent. The extrac has been treated in some variant concentration and then tested to bacteria with chloramfenicol and amphisillin trihidrat as comparison by diffusion agar method of disc paper. The result of antibacterial test showed that extraction of Cocos nucifera Linn can inhibit the growth of Esherichia coli and Shigella dysenteriae in concentration 500 mg/ml up to 10 mg/ml. The minimum concentration of extrac Cocos nucifera Linn who can inhibit the both of bacteria were 7,2 and 7 mm, and the minimum concentration of Chloramfenicol for Escherichia coli was 10 mcg/ml with diameter 7,5 mm and minimum concentration of Amphisillin trihidrat for Shigella dysenteriae was 140 mcg/ml with diameter 7,2 mm.

2010-08-24T00:00:00Z Dalimunthe, Aminah Nainggolan, Marline