Dewan Redaksi: Totok M. S. Soegandi (Ketua), Tarzan Sembiring (Wakil Ketua), Dyah Hardini (Sekretaris),
Anggota : Mochmad Ichwan, Supartono S, Iip Syarif Hidayat, Adiseno, Tigor Nauli, Elan
Djaelani, Linar Zalinar Udin, Anny Sulaswatty, Adrin Tohari, Heru Santoso, Kreshna
Amurwabumi, Masno Ginting, Rudy Subagja. Redaksi Pelaksana: Agusto W. Martosudirdjo, Kamaludin, Euis Setiawati, Siti Kania Kushadiani, Nanik Supriyanti.
Alamat Redaksi: UPT Balai Informasi Teknologi,
Kompleks LIPI Gd. 40,
Jl. Cisitu, Sangkuriang Bandung 40135
Telp. (022) 2502832, 2504265
Penerbit: LIPI Press, Anggota Ikapi, Jl. Gondangdia Lama (RP Suroso) No. 39 Jakarta 10350. Telp.: (021) 314–0228, 314–6942. Fax.: (021) 314–4591. e-mail: press@mail.lipi.go.id; bmrlipi@centrin.net.id; lipipress@centrin.net.id; press@lipi.go.id; penerbit@lipi.go.id
Daftar Isi
ISOLATION AND DETERMINATION OF MICROBE FROM
HIBISCUS LEAVES OF USAR
Yetti Mulyati Iskandar and Sri Priatni
Abstract
The most popular way of making tempe starter in Indonesia conventional involves the use of Hibiscus leaves (Hibiscus tiliaceus). Hibiscus is used because the underside of each leaf is covered with downy hairs, to which the mould mycelium and spores can adhere. This ingenious method is probably so popular because it produces the purest traditional starter, especially in central java. In taxonomic studies of Rhizopus sp strong emphasis has been placed on their morphological characteristics. The isolation and identification of microorganisms had been conducted through hibiscus leaves of usar.
The results of determination showed that hibiscus leaves of usar contained moulds such as Rhizopus oligosporus, Rhizopus arrhizus, Rhizopus oryzae, Mucor sp, and Moniella arbutens respectively. Bacteria such as Lactobacillus brevis, Lactobacillus plantarum, Enterobacter agglomerans, Enterobacter gergoviae, Pseudomonas aeroginosa and Klebsiella pneumonia , respectively. However, Rhizopus oligosporus grew very dominant.
Keywords: Rhizopus sp, Hibiscus leaf, bacteria, morphology.
RHEOLOGICAL BEHAVIOUR OF SALVIA HYDROGEL
AT TEMPERATURE AND PH VARIATION
Rike YUDIANTI, Myrtha KARINA, Jun-ichi AZUMA
Abstract
Rheological behaviour of natural hydrogel produced from seed of Salvia sclarea was investigated by using Rheometer UBM G1000 with cone and plate geometry measuring system. This is preliminary study to know rheological properties of gel under temperature and pH variation when water evaporation during heating was neglected. The hydrogel properties with concentration (1/4,1/2, 3/4, 1%) and pH (2,4,7,8,10) variations measured at heating condition (30, 40, 50, 60oC) show a change internal structure. Generally, enhancing elasticity occur at temperature increased from 30 to 60oC (G’>G”). During temperature of 30 and 40oC, G’ and G” tend to converge at the frequency terminal. Stronger gel is shown at temperature of 50 and 60oC whereas elasticity is greatest contribution within the accessible frequency range from the beginning of measurement.
Elasticity of network structure changed by increasing gel concentration from 1/4 to 1%. Solid-like behaviour from the beginning of measurement shown in concentration of ½, ¾ and 1% whereas G’ and G” tend to converge at the end of frequency. Abruptly strength reducing of hydrogel occurs at the lowest concentration of 1/4% with liquid-like behaviour (G”>G’) as evidenced through the rheological behaviour of the system. In the variouse pH, the hydrogel characteristic are vary. Transition from solid to liquid-like behaviour occurs at pH 8 and ultimately elasticity diminish at pH 10. Independency storage modulus within all frequency is shown at pH value of 2 which elasticity as dominant character. At neutral pH of 7, aggregation process of gel molecules occur near joining of G’ and G” at frequency terminal.
Keywords: rheology, rheometer, hydrogel, salvia sclarea
PENDUGAAN UMUR SIMPAN DODOL YANG DILAPISI EDIBLE FILM BERBASIS BIOSELULOSA DENGAN METODE ARRHENIUS
Lucia Indrarti, Elsy Rahimi Ch.
Abstract
Problem of dodol storage often arises due to several factors such as fungal growth and changes in aroma (rancidity) due to material ingredients composition, microbe activity, and packaging. To solve that problem, edible film was prepared by mixing biocellulose, carboxymethycellulose (CMC) and glycerol. Biocellulose thin film was applied to dodol and its shelf life was evaluated.
Effect of edible film on the shelf life of dodol was investigated by two steps experiment. T16 and T27 formula of edible film with 1, 1.5, and 2 mm of thickness were used in the first step experiment to evaluate its tensile strength. The best formulation, indicated by the highest tensile strength, was then applied for dodol packaging in second step experiment. Storage temperature was varied at 5, 25, and 35oC, respectively and stored for 4 weeks. Dodol quality was evaluated by total microbe parameter with Total Plate Count method and prediction of shelf life by Arrhenius method.
T27 edible film with 2 mm of thickness showed the best result, due to the highest tensile strength of 83.936 MPa. Shelf life prediction of dodol packaged with edible film (T27-2 mm) stored at 5oC was 49 days, whereas dodol packaged by edible film stored at 25 and 35oC was 33 and 28 days, respectively.
Keywords: edible film, biocellulose, composite, dodol, shelf life.
OPTIMASI DAN VERIFIKASI KROMATOGRAFI CAIR KINERJA TINGGI - UV UNTUK ANALISIS RESIDU PESTISIDA KARBAMAT
Retno Yusiasih dan Dyah Styarini
Abstract
Optimization carbofurane and carbaryl of carbamate pesticides analysis by using High Performance Liquid Chromatography equipped with Ultra Violet Detector (HPLC – UV) has been done. Maximum absorbance were detected at wave lenght of 275 nm (l275) using acetonitrile/H2O = 45/55 (v/v) as mobile phase isocratic mode. Carbofurane was eluted first, and followed by carbaryl compound. Verification of HPLC – UV on the optimum condition given by the instrument had a minimum detection of 0.06 mg.ml-1 for carbofurane and 0.04 mg.ml-1 for carbaryl compounds. Linearity with coefficient corelation r2 (determinant) value of 0.9702 in the range between concentration 0.06 - 0.15 mg.ml-1 for carbfurane and r2 value of 0.9874 in the range between concentration 0.04 - 0.15 mg.ml-1 for carbaryl. Precision of 0.30 % for retention time (Rt) and 7.28 % for peak area of carbofurane and 0.20 % for Rt and 4.63 % for peak area of carbaryl compounds.
Keywords: Optimization, Verification, Chromatography, Carbofurane, Carbaryl,Carbamate, Pesticide
CLONING OF BACILLUS LICHENIFORMIS A-AMYLASE GENE IN ESCHERICHIA COLI
S. Pudjiraharti, Tjandrawati M, S. Priatni, Dessy N and K. Asano
Abstract
In this study, thermostable a-amylase gene (amy) was obtained by amplifying the chromosomal gene of local thermophilic B.licheniformis with PCR technique using a pair of primers, which were designed based on the published nucleotide sequence. Cloning of the amplified amy gene was carried out using pGEMT vector and E. coli JM 109 host cell. Based on the digestion products of the recombinant plasmid by restriction enzymes, one clone having amy gene insert of 1450 bp was observed. Sub cloning of the gene using pET 16b expression vector and E. coli DH 5a host cell resulted one clone (EcD21) which was identified having pET 16b-amy by digestion method using restriction enzymes. Transformation of E. coli Bl 21 with pET 16 b-amy resulted more than 30 colonies of recombinants. Identification of the recombinants by using amylolytic activity test indicated that the recombinants showed higher amylolitic activity than the wild type. Production of a-amylase using one of the recombinants, EcB21 in Luria Bertani broth medium containing 1 ìg/ml ampicillin and 0.5mM IPTG incubated at 37oC, 150 rpm for 24 hours resulted enzyme unit activity of 756.25 U/ml and enzyme specific activity of 350,750 U/g protein. This result is five hundred times higher compared to B. licheniformis.
Keywords: a-amylase, B. licheniformis, PCR, Sequencing.
APLIKASI TEKNOLOGI DALAM MENUNJANG PENGELOLAAN LINGKUNGAN
Dyah Marganingrum
Abstract
In the river management, especially correlated with the river pollution level, data collecting are required, both the quality and quantity data (river flow) continuity. This paper describes the database application that correlated with the river system management. The aim of the database application was to facilitate in managing, accessing, and editing of data. The designing and managing of the database were done by using MS Access software. This data was grouped into three entities, those are river entity (the physical and flow data), monitoring entity (monitoring data of the water river quality and wastewater industry), and the pollution source entity (domestic, industry, agriculture, livestock breeding, and mining).The database application can also be added with spatial data. The spatial data is a data that has a geography reference (position on the surface of earth). This gives the solution that correlated with the problem of administrative border. Special program to do filling, taking, and editing data for end-user was done using the Borland-Delphi 6,0 program. This database application is useful for user or decision maker to get information concerning river condition easily, quickly, and informative.
Keywords : Application, Database, Watershed, Management, River
PENGENDALI KECEPATAN MOTOR INDUKSI 3 FASA DENGAN
EXTENDED KALMAN FILTER SEBAGAI
ESTIMATOR FLUKS DAN ROTASI
Demi Sutraprawata, Hariyadi
Abstract
The aim of this research is to develop the digital estimator models flux and speed of the induction motor on the basis of Extended Kalman Filter (EKF) algorithm. to replace the Flux and Rotation sensors in the induction motor control systems. Further more, the estimator would be integrated into speed 3 phase Induction Motor controller that based on the Field Oriented Control (FOC) system. To achieve this aim and to fulfill the simulation requirement the dynamic mathematical models was differentiated from the physical phenomena that represented of the induction motor. The simulation was performed and the result shown that the estimator model converged to the controlled trajectory after 25 iteration processes with the induction motor speed errors ± 2.5% distributed uniformly around the set-point value.
Keywords: Extended Kalman Filter (EKF), Field Oriented Control (FOC), Estimator, Algorithm, Flux, Rotation, Motor, Induction, Sensorless.
APLIKASI SISTEM THERMAL ENERGY STORAGE PADA SISTEM
PENGKONDISIAN UDARA DI INDONESIA
Ghalya Pikra, Tri Admono
Abstract
The paper presents a study of thermal energy storage application for air conditioning system of a shopping centre in Jakarta. There are two classifications of electrical tariff in Indonesia such as on-peak load tariff and off-peak load tariff. The tariff of on-peak load is twice higher of off-peak load tariff. Thermal energy storage (TES) is the method of energy management that could be applied for reducing operation cost of air conditioning system especially on peak load period. The study concerning the possibility application of this method based on Indonesian electrical tariff was conducted for a shopping centre in Jakarta as a case study. Two type air conditioning system such as conventional central air cooled system and thermal energy storage with air cooled chiller have been studied. The results showed that for estimated cooling load around 440 TR the application of TES air cooled ice chiller system could reduce annual operation cost up to 19 % relatively from conventional central air cooled system.
Keywords: Thermal energy storage, Air conditioning system, Electrical tariff, Operation cost.
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