Elektrodeposisi Lapisan Komposit Cu-al2o3 dalam Larutan Cuso4 yang Didoping dengan Partikel Nano Al2o3

ELEKTRODEPOSISI LAPISAN KOMPOSIT Cu-Al2O3 DALAM LARUTAN CuSO4 YANG DIDOPING DENGAN PARTIKEL NANO Al2O3. Lapisan komposit Cu-Al2O3 dibuat dengan menggunakan proses elektrodeposisi. Pada lapisan komposit ini, lapisan Cu berperan sebagai matriks komposit sedangkan nanopartikelAl2O3 berperan sebagai partikel penguat komposit (reinforcement). Lapisan komposit ini merupakan kelompok komposit bermatriks logam (MetalMatrix Composite). Proses elektro deposisi dilakukan pada media larutan elektrolit CuSO4, sedangkan arus listrik di suplai melalui rectifier (DC Current). Katoda yang digunakan pada proses ini adalah pelat Alumunium AA1100 dan anoda berupa grafit atau karbon. Besarnya arus yang digunakan pada proses ini adalah 0,3 A, sedangkan konsentrasi nanopartikel Al2O3 yang ditambahkan pada larutan elektrolit adalah 0,05 g/L. Proses dilakukan pada suhu kamar dan ukuran partikel nano yang digunakan adalah 50 nm. Variasi waktu proses elektrodeposisi adalah 15 menit, 30 menit dan 60 menit dan variasi konsentrasi larutan CuSO4 adalah 200 g/L, 220 g/L dan 240 g/L CuSO4 . Untuk mengetahui peranan dari nanopartikel yang ditambahkan, maka dilakukan beberapa pengujian dan pemeriksaan laboratorium seperti pengujian kekerasan, pemeriksaan strukturmikro. Pemeriksaan Scanning Electron Microscope (SEM) dan pengujian Electron Dispersive Spectroscopy (EDS). Pembuatan lapisan komposit ini bertujuan untuk mendapatkan karakteristik lapisan yang sifat mekaniknya lebih baik

Rekayasa Katalis Ni/Zn-HZSM-5 Untuk Memproduksi Biofuel Dari Minyak Bintaro

Sumber energi alternatif terbarukan sangat diperlukan pada masa kini, sebab penggunaan sumber energi fosil tidak dapat menjadi andalan untuk masa depan. Hal ini karena sumber energi fosil semakin menipis dan penggunaannya menghasilkan emisi CO2 yang tidak ramah lingkungan. Salah satu sumber energi alternatif yang menjanjikan adalah biofuel. Biofuel merupakan sumber energi terbarukan dan ramah lingkungan. Penelitian ini bertujuan untuk mempelajari pengaruh katalis berpromotor ganda Ni/Zn-HZSM-5 dan suhu terhadap proses perengkahan minyak bintaro untuk memproduksi biofuel. Variabel yang digunakan adalah perbandingan massa Ni terhadap Zn, perbandingan massa logam terhadap katalis total serta suhu. Parameter kualitas biofuel dapat dilihat dari nilai selektivitas. Selektivitas maksimum gasoline sebesar 52,42% tercapai pada suhu 350°C dan selektivitas maksimum kerosene sebesar 86,72% tercapai pada suhu 400°C pada pengguunaan katalis dengan perbandingan Ni:Zn sebesar 1:1 dengan logam 2% massa total katalis. Diperlukan penelitian yang lebih lanjut untuk memproduksi biofuel yang lebih berkualitas pada suhu yang lebih tinggi dan massa katalis yang lebih besar

Lampu Pintar Berbasis LED Dengan Multi Sensor

In this paper, we propose a LED-based smart lamp prototype that integrated with sensor. The smart lamp use information of people and lighting confirmation, to turn on or turn off the lamp automatically. In addition, the sensor calculates and balances flash and ambient light exposure to decrease the light, so that can make energy efficiently in use. PIR (Passive Infrared Receiver) and Ultrasonic sensor is preferred to detect people condition in one place and LDR (Light Dependent Resistant) is preferred to detect intensity of light. In experimental system of smart lamp obtain good condition where the average of illuminance 257,6 lux. The smart lamp can detect large and small movements caused by human beings and can provide a constant room lighting.keywords: Smart lamp, Presence detection, Ultrasonic Pada tulisan ini, sebuah lampu pintar berbasis LED berbasis integrasi sensor deteksi keberadaan dan sensor deteksi cahaya diusulkan. Sensor digunakan untuk menyalakan atau memadamkan lampu secara otomatis berdasarkan keberadaan orang disekitarnya. Selain itu, lampu pintar juga dapat mengatur tingkat pencahayaan yang dibutuhkan dengan memperhatikan cahaya ambien untuk mencegah terjadinya pencahayaan yang berlebih guna menghindari energi yang terbuang sia-sia. Deteksi keberadaan menggunakan penggabungan dua buah sensor yaitu PIR (Passive Infrared Receiver) dan Ultrasonik, sedangkan deteksi cahaya menggunakan sensor LDR (Light Dependent Resistant). Hasil pengujian mendapatkan sistem lampu penerangan bekerja dengan baik dan dapat memberikan pencahayaan sebesar 257,6 lux. Lampu Pintar tersebut sudah dapat mendeteksi gerakan besar dan kecil yang ditimbulkan oleh manusia dan dapat memberikan pencahayaan ruangan yang konstan

Molecular Weight and Structural Properties of Biodegradable PLA Synthesized with Different Catalysts by Direct Melt Polycondensation

Production of biodegradable polylactic acid (PLA) from biomassbased lactic acid is widely studied for substituting petro-based plastics or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst, γ-aluminium(III) oxide (γ-Al2O3) or zinc oxide (ZnO), in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for γ-Al2O3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol) than that from γ-Al2O3 (81,400 g/mol). The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1, whereas the PLA produced by two other polymerization methods – polycondensation and ring opening polymerization –showed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as –OH vibration peak and at 1,750 cm-1 as –C=O carbonyl vibrational peak

The effect of cationic surfactants on improving natural clinoptilolite for the flotation of cesium

Flotation using cationic surfactants has been investigated as a rapid separation technique to dewater clinoptilolite ion exchange resins, for the decontamination of radioactive cesium ions (Cs+) from nuclear waste effluent. Initial kinetic and equilibrium adsorption studies of cesium, suggested the large surface area to volume ratio of the fine zeolite contributed to fast adsorption kinetics and high capacities (qc = 158.3 mg/g). Adsorption of ethylhexadecyldimethylammonium bromide (EHDa-Br) and cetylpyridinium chloride (CPC) surfactant collectors onto both clean and 5 ppm Cs+ contaminated clinoptilolite was then measured, where distribution coefficients (Kd) as high as 10,000 mL/g were evident with moderate concentrations CPC. Measurements of particle sizes confirmed that adsorption of surfactant monolayers did not lead to significant aggregation of the clinoptilolite, while 4, highlighting the great viability of flotation to separate and concentrate the contaminated powder in the froth phase

The effect of pre-activation and milling on improving natural clinoptilolite for ion exchange of cesium and strontium

Natural clinoptilolite, of relatively low-grade, was investigated for its capability to remove cesium and strontium ions from water and simulated seawater. To improve its capacity, the material was pre-activated with concentrated NaCl and HCl solutions. Additionally, it was milled to a number of < 300 μm size fractions, to expose exchange sites. Electron microscopy was used to characterise the naturally occurring impurities, where regions of high iron and potassium content was shown to correlate to lower levels of cesium adsorption. Adsorption kinetics for natural and activated resins with 5, 300 and 1500 ppm salt solutions were fitted with the Pseudo-Second Order (PSO) rate model. Activation led to clear increases in initial adsorption rate for both Cs+ and Sr2+, but only enhanced the overall rate constant for Cs+, due to the weaker interaction of the Sr2+. Equilibrium isotherms were compared with Langmuir and Freundlich monolayer models, where the adsorption capacity (Qc) for Cs+ was 67 mg/g which increased by over 100% with NaCl activation to 140 mg/g. Values for Sr2+ were significantly lower at 35 mg/g, with a considerably smaller enhancement with activation to 52 mg/g. Milling of the natural clinoptilolite was found to increase Cs+ uptake to similar levels as activation, in a linear correlation with specific surface area; although, improvements for Sr2+ were again lower, due to its weaker interaction with surface sites. In simulated seawater solutions, all materials gave considerably reduced performance due to K+ ion competition, with Sr2+ uptake decreased more extensively compared to Cs+. Overall, this work highlights that pre-activation and milling of clinoptilolite can be used to significantly enhance the grade of the ore for nuclear effluent treatment in low-salinity conditions

Noise Suppression of Computed Tomography (CT) Images Using Residual Encoder-Decoder Convolutional Neural Network (RED-CNN)

In this study, an in-house residual encoder-decoder convolutional neural network (RED-CNN)-based algorithm was composed and trained using images of cylindrical polymethyl-methacrylate (PMMA) phantom with a diameter of 26 cm at different simulated noise levels. The model was tested on 21 × 26 cm elliptical PMMA computed tomography (CT) phantom images with simulated noise to evaluate its denoising capability using signal to noise ratio (SNR), comparative peak signal-to-noise ratio (cPSNR), structural similarity (SSIM) index, modulation transfer function frequencies (MTF 10 %) and noise power spectra (NPS) values as parameters. Evaluation of a possible decrease of image quality was also performed by testing the model using homogenous water phantom and wire phantom images acquired using different mAs values. Results show that the model was able to consistently increase SNR, cPSNR, SSIM values, and decrease the integral noise power spectra (NPS). However, the noise level on either training or testing data affects the model’s final denoising performance. The lower noise level on testing data images tends to result in over-smoothed images, as indicated by the shift of the NPS curves. In contrast, higher simulated noise level tends to result in less satisfactory denoising performance, as indicated by lower SNR, cPSNR, and SSIM values. Meanwhile, the higher noise level on training data images tends to produce denoised images with reduced sharpness, as indicated by the decrease of the MTF 10 % values. Further studies are required to better understand the character of RED-CNN for CT noise suppression regarding the optimum parameters for best results