Claim Missing Document
Check
Articles

Found 24 Documents
Search

EFFECTS OF pH ON CALCIUM CARBONATE PRECIPITATION UNDER MAGNETIC FIELD Nelson Saksono; Yuliusman Yuliusman; Setijo Bismo; Roekmijati Soemantojo; Azwar Manaf
MAKARA Journal of Technology Vol 13, No 2 (2009): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale MagneticTreatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation inhigh and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. Theobservation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetizedsolutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In highsuper-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulationprocess. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction whichindicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation ofmagnetization process has completed.Keywords: calcium carbonate precipitation, circulation flow, magnetic field
PENGARUH MEDAN MAGNET TERHADAP PROSES PRESIPITASI CaCO3 DALAM AIR SADAH Nelson Saksono; Setijo Bismo; Elsa Krisanti; Azwar Manaf; Roekmijati Widaningrum
MAKARA Journal of Technology Vol 10, No 2 (2006): November
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Studi Transformasi Fasa Sistem Besi Karbon Dengan Pengamatan Thermal Diferensial Pontas Sialagan; Azwar Manaf
Makara Journal of Science Vol 6, No 1 (2002): April
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Phase Transformation Studies of Fe-C System with Differential Thermal Analyzer: Phase transformation studies for ironcarbon(Fe-C) system have been done by means of Differential Thermal Analyzer, DTA. Fe-C samples of nominal compositionsfor respectively low carbon containing alloy (0.1 wt.%), hypo eutectoid (0.4 wt.%), and eutectoid (0.8 wt.%) were preparedby powder metallurgy process using pure Fe and C powder materials (>99 %) as the feed stock. Measurement by DTA in the temperature range 25 oC–1100 oC for the samples indicated that there are two endothermic temperatures transition in pure Fe sample respectively at 773.8 oC associated with phase transformation of ferromagnetic (α) to paramagnetic (β) and at 930 oC due to a phase transformation of β-ferrite to austenite (γ). The two transition temperature was also consistently observed in all Fe-C samples but with one additional temperature transition at about 753 oC associated with a phase transformation of pearlite to austenite. Data of heat change measurement in the temperature range 25 oC-1100 oC were subsequently used for determination of heat capacity, Cp for the Fe-C samples as the function of T. Cp (T) curves when fi tted by polynomial regression have resulted in regression coeffi cients between 0.8 and 1.0.Keywords: Pearlite, eutectoid, ferromagnetic, entalphy, iron-carbon system, phase transformation
FORMATION OF CaCO3 PARTICLE AND CONDUCTIVITY OF Na2CO3 AND CaCl2 SOLUTION UNDER MAGNETIC FIELD ON DYNAMIC FLUID SYSTEM Nelson Saksono; Setijo Bismo; Roekmijati Widaningroem; Azwar Manaf
MAKARA Journal of Technology Vol 15, No 1 (2011): April
Publisher : Directorate of Research and Community Engagement, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Hard water causes the CaCO3 scale formation on the pipe walls and heat exchanger equipments in industrial or domestic water processes. A great number of experimental researches on the prevention of the CaCO3 precipitation process by magnetic field have been carried out. In this research, Na2CO3 and CaCl2 solutions was magnetized in the circulated flow condition (dynamic fluid system). The velocity of fluid and the circulation time was modified to examine its influences to the magnetization process. CaCO3 content was measured by titration method of EDTA complexometry. Conductivity test was conducted to find out hydrate ion bonding. The results showed that magnetization increased the CaCO3 formation and the optimum process reaches for 10 minutes circulation on 0.554 m/s of flow rate. Magnetic field decreases the conductivities of Na2CO3 and CaCl2 solution, hence reduced the ion hydrate bonding. These results showed that magnetization on Na2CO3 and CaCl2 ionic solution was effective in controlling the CaCO3 formation by increasing CaCO3 precipitation. Keywords: CaCO3 conductivity, magnetic carbonate solution, precipitation
Isothermal and non-isothermal crystallization Kinetic behavior of zinc-ferrite formation in theLow temperature flow injection co-precipitation synthesis reactor Sasito, Edie; Soegijono, Bambang; Manaf, Azwar
Jurnal Spektra Vol 14, No 2 (2013): Spektra: Jurnal Fisika dan Aplikasinya
Publisher : Jurnal Spektra

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The kinetic behavior of zinc -ferrite crystallization process has been studied by co-precipitation of chlorine salt and alkaline solution. Either the parameter of temperature rate variation, pH previous of reactant and pH alkaline solution results non isothermal process was described by Ozawa equation,. There are significantly deferent in the taking both isothermal and non isothermal data. In the non- isothermal there are just oneexperiment can be sufficiency to reveal any crystal forming parameters but in the isothermal needs several different temperature experiments to reveals the parameter of crystal forming . In this research have be done one time non -isothermal experiment at means temperature 40 0C with temperature increase from 49 0C to 530C, and four time isothermal experiments at means temperature 60 0C,70 0C and 80 0C respectively. The sampling of experiment data have be done effectively using pH real- time video data logger. As a result the energy forming of the zinc ferrite both isothermal and non-isothermal are -4.27kcal/.mol,5.61kcal/mol respectively. The other kinetic parameter of crystallization and crystalline mechanism of both processes will be discussed.Keywords:co-precipitation, zinc-ferrite, non-isothermal process, crystallization, crystalline mechanism, data logger, kinetic behavior, flow injection co-precipitation synthesis.
SINTESIS PIGMEN BESI OKSIDA BERBAHAN BAKU LIMBAH INDUSTRI BAJA (MILL SCALE) Manaf, Azwar; Rochman, Nurul Taufiqu; Sukarto, Agus; Rahman, Tito Prastyo
Jurnal Fisika Vol 3, No 1 (2013)
Publisher : Jurnal Fisika

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Limbah industri baja (mill scale) digunakan sebagai alternatif bahan baku pigmen besi oksida. Kajian ilmiah ini menjelaskan proses pembuatan pigmen besi oksida melalui metode presipitasi dengan media air. Pigmen besi oksida yang menjadi target yaitu pigmen kuning goethit ( -FeOOH) dan merah hematit ( -Fe2O3). Goethit diperoleh dengan presipitasi menggunakan amonia dari proses awal terbentuknya ferricssulfat hasil reaksi asam sulfat (H2SO4) dengan limbah mill scale, sedangkan hematit diperoleh dengan proses pemanasan goethit pada temperatur 5000C dan 9000C. Analisa XRD digunakan untuk mengetahui senyawa pigmen yang terkandung dan penggunaan DTA untuk mengetahui pola perubahan fasa akibat proses pemanasan fasa goethit. Analisa warna pigmen menggunakan collorimetri L*a*b System. Warna pigmen yang diperoleh mempunyai tinting strength yang masih kurang dibandingkan dengan pigmen impor.
Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water Saksono, Nelson; Bismo, Setijo; Krisanti, Elsa; Manaf, Azwar; Widaningrum, Roekmijati
Makara Journal of Technology Vol 10, No 2 (2006)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (154.71 KB) | DOI: 10.7454/mst.v10i2.118

Abstract

Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness.Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated  samples. The results showed an increase of deposits formation rate and total number of precipitated CaCO3 of magnetically treated samples. The increase of concentration solution sample will also raised the deposit under magnetic  field. Microscope images showed a greater number but smaller size of CaCO3 deposits form in magnetically treated samples, and aggregation during the processes. X-ray diffraction (XRD) analysis showed that magnetically samples were dominated by calcite. But, there was a significant decrease of calcite’s peak intensities from magnetized  samples that indicated the decrease of the amount of calcite and an increase of total amorphous of deposits. This result  showed that magnetization of hard water leaded to the decreasing of ion Ca2+ due to the increasing of total CaCO3 precipitation process.
Effects of Ph on Calcium Carbonate Precipitation Under Magnetic Field Saksono, Nelson; Yuliusman, Yuliusman; Bismo, Setijo; Soemantojo, Roekmijati; Manaf, Azwar
Makara Journal of Technology Vol 13, No 2 (2009)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (187.585 KB) | DOI: 10.7454/mst.v13i2.165

Abstract

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale Magnetic Treatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation in high and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. The observation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetized solutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3 solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In high super-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulation process. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction which indicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation of magnetization process has completed.
Formation of CaCO3 Particle and Conductivity of Na2CO3 and CaCl2 Solution Under Magnetic Field on Dynamic Fluid System Saksono, Nelson; Bismo, Setijo; Widaningroem, Roekmijati; Manaf, Azwar
Makara Journal of Technology Vol 15, No 1 (2011)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (157.056 KB) | DOI: 10.7454/mst.v15i1.207

Abstract

Hard  water  causes  the  CaCO3  scale  formation  on  the  pipe  walls and  heat  exchanger  equipments  in  industrial  or domestic  water  processes.  A  great  number  of  experimental  researches  on  the  prevention  of the  CaCO3  precipitation process  by  magnetic  field  have  been  carried  out.  In  this  research,  Na2CO3  and  CaCl2  solutions  was  magnetized  in  the circulated  flow  condition  (dynamic  fluid  system).  The  velocity  of  fluid  and  the  circulation  time  was  modified  to examine  its influences  to  the  magnetization  process.  CaCO3  content  was measured  by  titration  method  of  EDTA complexometry.  Conductivity  test  was  conducted  to  find  out  hydrate  ion  bonding.  The  results  showed  that magnetization increased the CaCO3 formation and the optimum process reaches for 10 minutes circulation on 0.554 m/s of flow rate. Magnetic field decreases the conductivities of Na2CO3 and CaCl2  solution, hence reduced the ion hydrate bonding. These results showed that magnetization on Na2CO3 and CaCl2 ionic solution was effective in controlling the CaCO3 formation by increasing CaCO3 precipitation.
PHYSICAL CHARACTERISTICS AND MAGNETIC PROPERTIES OF BAFE12O19/SRTIO3 BASED COMPOSITES DERIVED FROM MECHANICAL ALLOYING Widodo, Rahmat Doni; Manaf, Azwar
Sainteknol : Jurnal Sains dan Teknologi Vol 14, No 2 (2016): December 2016
Publisher : Unnes Journal

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v14i2.8994

Abstract

Barium hexaferrite and strontium titanate are well established permanent magnet and piezoelectric materials which are technologically and scientifically attractive due to their potential for various applications in the field of magnetic electronics functional materials. However, the material properties for both require a careful control of grain structure as well as microstructure design to meet a specific application. In this work, we report some results of materials characterization especially particles and grains which were promoted during mechanical milling of a BaFe12O19/SrTiO3 composite system. These are including mean particle size characterization by Particle Size Analyzer and mean grain size determination by means of line broadenning analysis employing a step scanning counting in XRD apparatus for composite powders at various milling time up to 60 hours. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ~8 μm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean grain size of the particles was found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100 oC the milled powder transformed into particles of nanograin. In thireport, microstructure as well as magnetic properties for the composite is also briefly discussed.