Politeknik Teknologi Nuklir Indonesia

Telah dilakukan penelitian mengenai degradasi zat warna azo jenis metil orange menggunakan mesin berkas elektron 350 keV/10mA. Penelitian ini bertujuan untuk mengetahui pengaruh radiasi berkas elektron, yaitu pengaruh dosis radiasi, pH, dan konsentrasi awal cuplikan. Selain itu dilakukan analisis kualitatif terhadap senyawa hasil degradasi. Proses iradiasi ini menggunakan dosis radiasi 5, 10, 20, 30 dan 40 kGy dengan energi operasi 300 keV dan kecepatan konveyor 2.7 cm/detik. Terhadap cuplikan ini diamati variasi pH dan variasi konsentrasi awal. pH metil orange diatur menjadi 2, 7, dan 12 dengan penambahan H2SO6N atau NaOH6N. Konsentrasi awal divariasi menjadi 10, 50, dan 100 ppm. Efisiensi degradasi dihitung dengan mengukur pengurangan intensitas warna cuplikan setelah iradiasi menggunakan spektrofotometer UV-Vis. Untuk analisis kualitatif senyawa hasil degradasi digunakan alat High Performance Liquid Chromatography, HPLC Hasil penelitian ini menunjukkan, bahwa semakin besar dosis radiasi semakin besar pula efisiensi degradasi. Pada variasi pH, efisiensi degradasi tertinggi diperoleh pada pH 2 dengan efisiensi 37.74 %. Pada variasi konsentrasi awal, diperoleh efisiensi tertinggi pada konsentrasi awal 10 ppm dengan efisiensi 21.54%. Lama waktu iradiasi adalah kira-kira 2-5 detik.

PENGARUH TEGANGAN DAN WAKTU PADA PENGOLAHAN LIMBAH RADIOAKTIF URANIUM DAN THORIUM DENGAN PROSES ELEKTROKOAGULASI. Metode pengolahan limbah radioaktif dengan metode fisika dan kimia yang telah dilakukan dinilai kurang efektif, memerlukan waktu yang lama dan biaya yang mahal. Untuk itu perlu dilakukan pengolahan limbah uranium dan thorium dengan proses elektokoagulasi untuk memisahkan uranium dan thorium dalam limbah cair. Limbah yang digunakan memiliki kadar kontaminan Uranium dan Thorium 500 mg/liter. Pengolahan dilakukan dengan tegangan 10V, 12,5V, dan 15 volt dengan waktu 10,20,30,40,50,dan 60 menit dengan elektroda alumunium. Hasil penelitian menunjukkan effisiensi penurunan kontaminan terbaik pada pengolahan ini diperoleh pada kondisi 12,5V dan waktu 60 menit untuk uranium, dengan efisiensi sebesar sebesar 97,2 %, dan thorium pada 12,5 V waktu 30 menit dengan efisiensi penurunan sebesar 99,6 % .

THE EFFECT ADSORBENT VARIATION AND URANIUM CONCENTRATION FOR URANIUM ADSORPTION FROM EFFLUENT PROCESS. Research The Effect of Variation Adsorbent and Concentration of Uranium Towards The Uranium Adsorption from Effluent Process has been carried out. The purpose of this research is to determine the optimum adsorption capacity of uranium adsorbent and adsorbent performance in effluent process. The variables to be analyzed is concentration of effluent process and kind of adsorbent. This research using adsorbent which is the result of PTBIN – BATAN research with BBCA (II) code. The analysis are conducted by using UV-Vis spectrometry. The result of this research shows that adsorption constancy equation model follow isotherm adsorption of Langmuir model : qm (mg/g) magnet composite = 90,909; qm (mg/g) magnet = 50; qm (mg/g) activated carbon = 41,66. The most effective adsorbent to adsorp uranium is magnet composite. The optimum adsorption capacity reached when the adsorbent amount which is adsorp in the maximum value. The optimum adsorp

Flood disasters occur frequently in Indonesia and can cause property damage and even death. This research aimed to provide rapid flood mapping based on remote sensing data by using a cloud platform. In this study, the Google Earth Engine cloud platform was used to quickly detect major floods in the Barito watershed in South Kalimantan province, Indonesia. The data used in this study were Sentinel-1 images before and after the flood event, and surface reflectance of Sentinel-2 images available on the Google Earth Engine platform. Flooding is detected using the threshold method. In this study, we determined the threshold using the Otsu method and statistical sampling thresholds (SST). Four SST scenarios were used in this study, combining the mean and standard deviation of the difference backscatter of Sentinel-1 images. The results of this study showed that the second SST scenario could classify floods with the highest accuracy of 73.2%. The inundation area determined by this method was 4,504.33 km2. The first, third and fourth SST scenarios and the Otsu method could reduce the flood load with an overall accuracy of 48.37%, 43.79%, 55.5% and 68.63%, respectively. The SST scenario is considered to be a reasonably good method for rapid flood detection using Sentinel-1 satellite imagery. This rapid detection method can be applied to other areas to detect flooding. This information can be quickly produced to help stakeholders determine appropriate flood management strategies.

ABSTRAK KINETIKA REAKSI PEMISAHAN Zr – Hf PADA EKSTRAKSI CAIR-CAIR DALAM MEDIA ASAM NITRAT. Telah dilakukan penelitian kinetika reaksi pemisahan Zr-Hf pada ekstraksi cair-cair dalam media asam nitrat. Penelitian ini dilakukan untuk menentukan kinetika ekstraksi cair-cair pada pemisahan Zr-Hf yaitu konstanta kecepatan reaksi, konstanta Arrhenius, dan energi aktivasi. Penelitian dilakukan dengan cara mencampurkan zirkonil nitrat dengan TBP-kerosen dengan perbandingan tertentu ke dalam bejana berpengaduk dan dipanaskan. Cuplikan filtrat fase air dianalisis menggunakan alat pendar sinar-X. Hasil penelitian menunjukkan bahwa kinetika ekstraksi mengikuti reaksi orde satu dengan konstanta kecepatan reaksi, k = 2,242 e -20,8/T menit -1 , energi pengaktif (E) sebesar 590,150 kal/mol dan konstanta Arrhenius (A) sebesar 0,8075 menit -1 dengan persamaan kecepatan reaksi: - r A = 2,2423 e - 0,0208 C A KATA KUNCI : k inetika reaksi, ekstraksi, TBP, zirkonium, hafnium ABSTRACT REACTION KINETIC OF SEPARATION OF Zr – Hf IN LIQUID - LIQUID EXTRACTION IN ACID NITRATE MEDIA. The reaction kinetic of Zr-Hf separation in liquid-liquid extraction in nitric acid media has been studied. This research was done to determine the kinetic of liquid-liquid extraction in the separation of Zr-Hf which consists of the reaction rate constant, Arrhenius constant, and activation energy. The research carried out by mixing zirconil nitrate with TBP-kerosene with a certain ratio into a stirred vessel and heated. Filtered samples of the water phase were analyzed using X-ray fluorescence instrument. The results showed that the kinetic of extraction followed the first order reaction with reaction rate constant, k = 2.242 e -20,8/T min -1 , activation energy (E) = 590.1501 cal/mol and Arrhenius constant (A) = 0.8075 min -1 with the reaction rate equation: - r A = 2.2423 e- 0, 0208 CA. FREE TERMS : reaction kinetic, extraction, TBP, zirconium, hafnium Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Times New Roman; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}

Arduino UNO R3 is one of the cheapest and easiest microcontroller boards that has great potential to be used as a basis for the measurement system. This study aims to develop measurement system of crude oil capacitance by using IDCs(Interdigital Capacitors). By knowing the value of crude oil capacitance, the crude oil permittivity value can be calculated. The crude oil permittivity value data is extremely needed in making crude oil heating systems using microwaves. The study used IDC sprinted on a PCB board with a copper layer as the electrode. Then, the system measurement results were compared with the results of PM 6303 RCL meter Phillip type A frequency measurement of 1 kHz which was used as reference data to determine the extent of measurement errors. From the results obtained, it is known that the error value of the Arduino UNO R3 based capacitance repeatability measurement is 0.47%. While the results of the linearity test measurement of crude oil capacitance measurement of temperature increases using the Arduino Uno-based IDCs sensor, the R2 value is 0.87. Thus it can be seen that the Arduino UNO R3-based capacitance measuring device has quite good sensor characteristics.

Hydrogels have been developed for several decades for various medical applications including wound dressing application. To accelerate wound healing process, Jatropha multifida sap was added to the hydrogel before crosslinking using electron beam. The method for the production of modified polyethylene oxide-polyethylene glycol dimethacrylate (PEO-PEGDMA) hydrogel was developed by dissolving Jatropha multifida sap into PEO-PEGDMA solution prior to crosslinking via electron beam. Various concentration of Jatropha multifida sap (0% to 15%) was irradiated with electron beam to prepare the hydrogel film. Gel fraction, swelling ratio, water vapour transmission rate and tensile strength were measured. Chemical structure was analysed using Fourier Transform Infrared Spectroscopy (FTIR). The results showed that the value of gel fraction and swelling ratio of hydrogel decreases linearly with increasing concentration of jatropha mulitifida. In contrary, water vapour transmission rate increase steadily. Tensile strength and elongation of hydrogel also increases with the increasing of Jatropha multifida content and reach the optimum value (6.20 N/mm2 and 6.09%) at concentrations of 15%. These results show that the PEO-PEGDMA crosslinked hydrogel film can be developed by adding Jatropha multifida sap with higher tensile strength using electron beam irradiation.

PENGAMATAN STRUKTUR MIKRO PADA KOROSI ANTAR BUTIR DARI MATERIAL BAJA TAHAN KARAT AUSTENITIK SETELAH MENGALAMI PROSES HEAT PEMANASAN. Telah dilakukan pengamatan korosi antar butir pada material baja tahan karat austenitik jenis SS 304 setelah mengalami proses perlakuan panas (heat treatment) pada selang suhu (400-950) oC dengan variasi waktu pemanasan (holding time) yaitu 1 jam, 3 jam, 3,5 jam, dan 4 jam. Sebelum dan sesudah proses perlakuan panas, struktur mikro sampel dianalisis menggunakan mikroskop optik dan SEM (Scanning Electron Microscope). Komposisi kimia pada daerah di sekitar batas butir diamati menggunakan SEM-EDS (Energy Dispersive X-ray Spectrometer). Hasil pengamatan menunjukkan bahwasampel yang mengalami perlakuan panas di bawah suhu sensitisasi yakni pada suhu400 oC, ternyata korosi antar butir tidak teramati. Untuk sampel yang mengalami perlakuan panas pada suhu sensitisasi yakni pada selang suhu (500-900) oC, ternyata korosi antar butir dapat teramati dengan jelas. Sedangkan untuk sampel yang mengalami perlakuan panas di atas suhu sensitisasi yaitu pada suhu 950 oC, ternyata korosi antar butir masih dapat teramati tetapi tidak sejelas sampel yang mengalami perlakuan panas pada suhu sensitisasi. Dari analisis komposisi kimia di sekitar batas butir ditemukan adanya penurunan kandungan karbon (C) yaitu dari 0,61 % massamenjadi 0,47 %massa, dan untuk khrom (Cr) dari 18,37 % massa menjadi 17,76 %massa.

HighlightColloids in dairy wastewater could be destabilized by adding ferric chlorideAspergillus niger could increase protein and decreased the crude fiber in wheat branWheat bran fermentation could be carried out in room temperature during three daysFish feed formulation was conducted by solving simultaneous linear equationsSludge of dairy wastewater and fermented wheat bran could be utilized as fish feedAbstractDairy wastewater contains suspended solids, which are very difficult to settle naturally. This waste could be treated by using ferric chloride, due to its ability to bind suspended solid and to form brown solid of Iron (III) hydroxide. The optimal amount of FeCl3 in coagulating dairy wastewater was 0.15 g of FeCl3 for every 250 mL of wastewater. This sludge could be utilized into something useful for the organism. The sludge of dairy wastewater could be mixed with other ingredients to make fish feed. Wheat bran, one of the ingredients used to make fish feed, was fermented using Aspergillus niger to increase the crude protein content and to lower crude fiber content. The addition of fermented wheat bran in fish feed formulation could increase the crude protein content in feed B (which had 0.085% iron) by 5.78% and feed C (which had 1.703% iron) by 5.17%. By using simultaneous linear equations, fish feed formulation was conducted by adding sludge of dairy wastewater, fermented wheat bran, rebon flour, starch, and vitamin C. In this research, two variations of fish feeds were made (feed B and feed C). The results indicated that feed B and feed C had better stability and buoyancy than feed A, as the commercial feed. Feed C also had the biggest crude protein of all feeds, amounting to 32.057%. Feed C also gave the best result in increasing nile tilapia’s growth rate. The result showed that sludge of dairy wastewater and fermented wheat bran could be added to fish feed formulation.

ABSTRACTThe lack of consumable water in urban and industrial-dense areas encourages research on clean water treatment methods. Some current treatment methods, such as precipitation, adsorption, and UV light irradiation are ineffective for water with high levels of suspended solids, organic matter, and turbidity. Therefore, alternative approaches are required to support the availability of clean and consumable water. The membrane technology is an alternative filtration method proposed in the East Surabaya's municipal waterworks area. The membrane filtration method is quite simple and easy to operate. This study aimed to determine the performance of cellulose acetate-based porous plate membranes synthesized by phase inversion for E. coli bacteria's ultrafiltration. As a raw material, cellulose acetate is preferred because of its high hydrophilicity and good biocompatibility. Membrane synthesis was carried out through the phase inversion method with acetone solvents and non-solvent water in the coagulation bath. The positive test for E. coli bacteria was carried out through the MPN (Most Probable Number) method on the municipal waterworks water samples before and after filtering with membranes. The results showed that the synthesis of cellulose acetate membrane had good homogeneity. This result was supported by the results of ANOVA single factor statistical data analysis. Also, cellulose acetate membrane had good permeability and flux performance as ultrafiltration of E. coli bacteria with a flux of 37.25 L/m2.hour.bar at a sufficient pressure of 5 bar. Test results for the presence of E. coli bacteria in PDAM water samples using the MPN method gave an initial indication that the water sample after filtration with cellulose acetate membrane was negative. Keywords: membrane, cellulose acetate, permeability, water fluxABSTRAKMinimnya air bersih yang layak konsumsi di daerah perkotaan dan padat industri mendorong penelitian tentang metode pengolahan air bersih. Kurangnya efektivitas metode pengolahan sebelumnya seperti pengendapan, adsorbsi, dan penyinaran dengan sinar UV untuk air dengan kadar suspended solids, zat organik, dan kekeruhan yang tinggi, diperlukan metode alternatif untuk mendukung ketersediaan air bersih layak konsumsi. Metode filtrasi alternatif yang ditawarkan di PDAM di kawasan Surabaya Timur. Metode filtrasi dengan membran sangat sederhana dan mudah dalam operasionalnya. Penelitian ini bertujuan untuk mengetahui kinerja membran plat berpori berbasis selulosa asetat yang disintesis secara inversi fasa untuk ultrafiltrasi bakteri E.coli. Selulosa asetat dipilih sebagai bahan baku membran karena selulosa asetat merupakan bahan polimer yang memiliki hidrofilitas tinggi dan biokompatibilitas yang baik. Sintesis membran dilakukan melalui metode inversi fasa dengan pelarut aseton dan nonpelarut air dalam bak koagulasi. Uji positif bakteri E.coli dilakukan melalui metode MPN (Most Probable Number) pada sampel air PDAM sebelum dan sesudah difiltrasi dengan membran. Hasil penelitian menunjukkan bahwa sintesis membran selulosa asetat memiliki homogenitas baik yang ditunjukkan oleh hasil analisis data statistika ANOVA single factor. Selain itu, membran selulosa asetat memiliki kinerja permeabilitas dan fluks yang baik sebagai ultrafiltrasi bakteri E.coli dengan ketercapaian fluks sebesar 37,25 L/m2.jam.bar pada tekanan efektif sebesar 5 bar. Hasil uji keberadaan bakteri E.coli pada sampel air PDAM dengan metode MPN memberikan indikasi awal bahwa sampel air setelah filtrasi dengan membran selulosa asetat adalah negatif.Kata kunci: membran, selulosa asetat, permeabilitas, fluks air

Application guides tourist sites in Yogyakarta, is a system that provides convenience to the travelers reference to tourist sites and public facilities such as gas stations, hotels, restaurants and souvenier shops on the application. With this application accessing information to become more effective and efficient use of smartphones to better facilitate the search of tourist sites that use LBS, featuring the categories of travel (natural tourism, education and cultural / historical), provide search facility tourist sites based on cost-owned using minimal android app 2.2 (Froyo). The method of using the system development model of HIPO and relation table, the implementation phase of software development using Windows7, Javascript and MySQL database. Android based applications can facilitate the user to travel to locations with existing costs

SINTESIS SILIKA XEROGEL DARI ABU DAUN BAMBU UNTUK ADSORPSI LIMBAH SIMULASI URANIUM. Telah dilakukan penelitian tentang sintesis silika xerogel dari abu daun bambu dengan metode sol gel menggunakan prekursor natrium silikat untuk adsorpsi limbah simulasi uranium. Abu daun bambu mangandung sekitar 58% silika yang bisa dimanfaatkan sebagai bahan baku pembuatan silika xerogel. Tujuan penelitian ini adalah untuk mengetahui pengaruh pH dan waktu aging serta mengetahui karakter silika xerogel, model isoterm adsorpsi dan termodinamika adsorpsi uranium oleh silika xerogel . Karakterisasi silika xerogel yang dilakukan adalah menentukan gugus fungsi, uji kristalinitas dan luas permukaan. Identifikasi gugus fungsi dan struktur kristal menggunakan FTIR dan XRD. Luas permukaan silika xerogel ditentukan dengan metode metilen biru. Hasil penelitian menunjukan bahwa sintesis silika xerogel terjadi pada pH optimum 7 dengan waktu aging optimum 3 jam. Hasil karakterisasi silika xerogel pada keadaan optimum menunjukkan luas permukaan sebesar 177,2858 m2/g . Spektra Infra Red silika xerogel hasil sintesis mengandung gugus silanol (Si-OH) dan siloksan (Si-OSi) serta data XRD memperlihatkan silika xerogel berstruktur amorf. Hasil percobaan menunjukkan bahwa adsorpsi uranium dengan silika xerogel mengikuti model isoterm Langmuir. Dari hasil evaluasi parameter termodinamika, adsorpsi uranium dengan silika xerogel merupakan adsorpsi kimia dan bersifat endoterm.

Kartini's Reactor simulator design based on LABVIEW. Kartini’s reactor simulator design has been done to provide a system that can be used as a traning hardware for reactor operator by applying PLC Siemens S7 as a control modul and LabVIEW software as a data processor. The purpose of this research is to design a simulator system to operate Kartini’s Reactor based on reactor kinetics modeling using PLC Siemens S7 as a CRDM controller. LabVIEW software is use as data acquisition and data information processing using reactor kinetics formula to convert the change of height position of control Rod into power information. Control Rod position that obtained from CRDM control will be sent to PC and being processed by software to obtain power. Power that obtained from simulation at 100 kW operation are 100% safety Rod, 60% SHIM Rod, and 37.05% regulator Rod.

Low-carbon steel is often used for welding joints, whether in the form of structural steel or other materials; the application of this material is used in shipbuilding, bridge construction, and other fields. Welding inspection is needed to determine the quality of the weld. Visual inspection and non-destructive testing (NDT) are techniques in welding inspection. This study aims to determine the results of visual inspection and non-destructive testing (NDT) on welding joints of low-carbon steel produced by GMAW. The welding joints used are V-butt joints with a bevel angle of 300, 10 mm thick plate, 2.6 mm root gap, variations in welding layers: 3 layers (root pass, filler pass, and capping), and 4 layers (root pass, 2 filler passes, and capping), filler metal ER 70S-6 0.8 mm, and CO2. Volts, current, travel distance, and shielding gas flow rate are welding parameters. The tests carried out were visual inspection referring to limits for imperfections in ISO 6520-1, non-destructive tests (NDT) that were carried out, namely penetrant tests and radiography tests. The visual inspection and non-destructive testing (NDT) on specimen 1 reveal an internal defect, specifically a lack of fusion; the specimen should be rejected. Specimen 2 shows an imperfection in the surface area, namely in the form of spatter (2 spots), and there are internal imperfections in the form of porosities with an area of less than 3%. The specimen should be accepted.

Kejadian station blackout (SBO) pada PLTN Fukushima Daiichi pada Maret 2011 di Jepang menjadi latar belakang yang penting untuk kegiatan penelitian tentang sistem pendinginan pasif. Pengaruh perubahan densitas fluida di daerah panas menimbulkan gaya apung (buoyancy force) dan pengaruh perubahan densitas fluida pada keadaan dingin menimbulkan gaya gravitasi (gravitational force) sehingga terjadi sirkulasi alam pada fluida kerja (air) di sepanjang untai. Tujuan penelitian dilakukan untuk mengetahui batasan operasi sehingga terjadi sirkulasi alami dan menentukan jenis aliran yang terjadi berdasarkan hasil perhitungan. Penelitian dilakukan secara eksperimental berdasarkan variasi setting temperatur air dalam tangki pemanas dan daya listrik di heater (variasi tegangan regulator). Analisis dilakukan berdasarkan grafik laju aliran sirkulasi alam yang terjadi pada untai FASSIP 03 NT selama komisioning. Hasil analisis dan perhitungan, laju aliran sirkulasi alam yang terbentuk adalah rejim aliran turbulen dengan rentang bilangan Reynolds (Re) dari 4305,8 – 7705,4. Dengan terjadinya aliran jenis turbulen pada untai FASSIP-03 NT berakibat permindahan panas yang terjadi menjadi lebih baik.

As one of advance nuclear reactor design, capability to model and analyze the pebble bed reactor is important. Availability and capability of an accurate open source and open access software for pebble bed reactor analysis is strategic. It can broaden the involvement of more student and researcher which finally may improve the research and development in this field. Current study aim to develop the pebble bed core model and perform a criticality study of HTR-10 core design. This study exploit the capability of openMC software to model a double heterogenety geometry using a TRISO Pack Model Building based on random sequential packing and closed random packing. Physical parametric surveys of the developed model show an expected results in which the model able to reflect the negative reactivity feedback of HTR-10 design. The critical height of HTR-10 model with helium from current model, VSOP, and MCNP are 125.881 cm, 125.804 cm, 126.116 cm, respectively. A code-to-code criticality analysis comparison of current model with VSOP and MCNP code reported by INET shows a good comparison and suggest that current method can be used for further pebble bed analysis.

Sabut kelapa adalah salah satu limbah lignoselulosa yang dapat dikonversikan menjadi bioetanol. Konversi bioetanol pada penelitian ini dilakukan melalui beberapa tahapan yaitu proses pre-treatment, proses Saccharification and Simultaneous Fermentation (SSF), dan proses pemurnian. Proses pre-treatment sebagai proses pemecahan ikatan lignoselulosa menjadi poin utama dalam proses konversi biomassa lignoselulosa. Penelitian ini dilakukan untuk mengetahui pengaruh iradiasi gamma terhadap pemecahan ikatan lignoselulosa pada proses pre-treatment tersebut. Proses iradiasi gamma divariasikan pada dosis sebesar 0 kGy, 100 kGy, 150 kGy, 200 kGy, 250 kGy dan dilanjutkan pre-treatment secara kimia menggunakan NaOH 4%. Kemudian dilanjutkan proses pemurnian setelah proses SSF selama 72 jam. Kadar bioetanol yang diperoleh setelah proses pemurnian diukur menggunakan metode refraktometri dan piknometri. Pada penelitian ini diperoleh kadar bioetanol tertinggi pada dosis iradiasi gamma 200 kGy, yaitu 35,15% untuk metode refraktometri, dan 36,77% untuk metode piknometri. Hasil tersebut jauh lebih tinggi bila dibandingkan dengan kadar bioetanol tanpa iradiasi gamma yaitu 2,45% untuk metode refraktometri, dan 6,92% untuk metode piknometri. Penelitian ini menunjukkan bahwa metode pre-treatment dengan iradiasi gamma dapat menghasilkan kadar bioetanol yang lebih tinggi dibandingkan tanpa menggunakan iradiasi gamma.
 Coconut husk is one of lignocellulosic wastes that can be converted into bioethanol. Bioethanol conversion in this study was carried out through several stages, namely the pre-treatment process, the Saccharification and Simultaneous Fermentation (SSF) process, and the purification process. The pre-treatment process as the process of breaking lignocellulosic bonds becomes the main point in the process of lignocellulosic biomass conversion. This research was conducted to determine the effect of gamma irradiation to breaking lignocellulosic bonds on the pre-treatment process. Gamma irradiation process was varied in doses of 0 kGy, 100 kGy, 150 kGy, 200 kGy, 250 kGy and continued with chemical pre-treatment using 4% NaOH. Then the purification process was continued after the SSF process for 6 days. Bioethanol levels obtained after the purification process were measured using refractometry and picnometry methods. In this study, the highest levels of bioethanol were obtained at a gamma irradiation dose of 200 kGy, namely 34.93% for the refractometry method, and 26.67% for the picnometry method, respectively. These results are much higher when compared to bioethanol levels without gamma irradiation, which is 2.25% for the refractometry method, and 5.49% for the picnometry method, respectively. This study shows that the pre-treatment method with gamma irradiation can produce higher levels of bioethanol than without using gamma irradiation.

Iron was needed in the world to all components, so it was important to determine iron’s concentrate. This research determined buffer pH optimation and the consentration of K 2 C 2 O 4 reductor. Reduction of 5 ppm Fe 3+ to Fe 2+ have been investigated. The first experiment was determination of λ maks and than various pH and concentration of K 2 C 2 O 4 as reductor in order that determination of optimum condition. The result showed that λ maks was 520 nm and pH 4,5 with 3 ppm of K 2 C 2 O 4 was effective to reduce 5 ppm of Fe 3+ to Fe 2+ in acid conditions forming [(Fe(C 12 H 8 N 2 ) 3 ] 2+ complex by spectrophotometric UV-Visible. But in base solution, this complex was not formed. Both acid and base conditions were effective and accurate, case of value of RSD under 20 ppt and CV under 2%. This indicator showed that this method was good.

Dalam ortopedi UHMWPE sering digunakan sebagai bantalan materi (tibial tray) pada sendi lutut buatan. Namun dalam penggunaannya, keausan bahan UHMWPE merupakan salah satu faktor utama yang memperpendek umur pakai sendi lutut buatan sehingga diperlukan metode untuk meningkatkan sifat mekanik UHMWPE. Tujuan penelitian ini adalah untuk mengetahui pengaruh radiasi sinar gamma terhadap sifat mekanik dan tingkat keausan dari UHMWPE sehingga dapat memenuhi kualifikasi bahan baku pembuatan tibial tray serta mengetahui dosis optimum yang diperlukan UHMWPE agar diperoleh bahan yang tahan terhadap keausan dan memiliki sifat mekanik yang lebih baik. Pembuatan tibial tray dilakukan dengan metode molding pressure dengan radiasi gamma. Pembuatan film UHMWPE dilakukan dengan hot press pada 170 °C selama 3 menit dan tekanan 200 kg/cm2. Kemudian film tersebut dipanaskan ke dalam furnace pada 128 oC selama 100 menit dan diradiasi dengan irradiator karet alam (IRKA) pada dosis 0 kGy, 50 kGy, 100 kGy, 125 kGy dan 150 kGy. Berdasarkan hasil karakterisasi sifat tibial tray dengan XRD, FT-IR, alat uji tarik, alat uji kekerasan, dan alat uji keausan, dapat disimpulkan bahwa efek radiasi terhadap polimer UHMWPE adalah terbentuknya ikatan silang dan degradasi bahan. Sehingga, semakin tinggi dosis radiasi dihasilkan sifat bahan yang semakin keras serta tahan terhadap aus. Selain itu, dapat diketahui bahwa dosis 100 kGy merupakan dosis optimal untuk meningkatkan sifat mekanik bahan.

Telah dilakukan penelitian tentang pengaruh matriks terhadap pencacahan sampel menggunakan spektrometer gamma. Tujuan penelitian ini adalah mengetahui pengaruh matriks terhadap sistem pencacahan, Bahan yang digunakan adalah sumber standar Solution 2908 yang merupakan sampel hasil interkomparasi dengan IAEA terdiri dari 54Mn, 60Co, 65Zn, 109Cd, 133Ba, 134Cs, 137Cs,210Pb, dan 241Am dan larutan standar yang terdiri dari 133Ba, 152Eu, dan 241Am. Sumber standar tersebut mempunyai rentang energi dari 59 keV sampai 1408 keV. Matriks yangdigunakan berupa rumput, abu rumput, sludge, air, tanah, pasir, pasir silika, dan pasir vulkanik dengan rentang densitas dari 0,226 g/cm3 sampai 1,760 g/cm3. Matriks yang telah diberi larutan radioaktif ini kemudian dimasukkan dalam vial ID 57 mm H 50 mm. Hasil pengujian dengan t-test menunjukkan bahwa seluruh radionuklida terdistribusi merata dalam setiap matriks. Data awal menunjukkan bahwa densitas matriks berpengaruh secara signifikan pada sistem pencacahan spektrometer gamma, terutama pada energi rendah. Semakin besar densitas maka efisiensi pencacahan akan menurun.Validasi hasil penelitian ini, memberikan nilai penyimpangan < 5%, yang dianggap baik berdasarkan ketentuan batasan dari IAEA, yaitu < 8%.