Based on the 2014 Regional Autonomy Law, the implementation of legal metrology in the form of cal... more Based on the 2014 Regional Autonomy Law, the implementation of legal metrology in the form of calibration, re-calibration and supervision is now the authority of the district/city. This study is expected to provide information related to legal metrology in general and particularly the importance of implementing metrological supervision in the regions. This research was conducted with a qualitative approach with the method of literature review and case studies in Bangka Selatan Regency. The low number of Measuring, Dosing, Weighing Equipment and Their Equipment (UTTP) and Packaged Goods (BDKT) in accordance with the provisions of the legislation is the main factor that causes the importance of this metrological supervision activity to be carried out, in addition to the low level of public understanding or knowledge regarding metrology. legal. In the end, effective metrological monitoring activities can help create an Orderly Measurement Area that is able to provide protection to cons...
This research aimed to produce zinc oxide (ZnO) nanostructure via a low temperature<br> hyd... more This research aimed to produce zinc oxide (ZnO) nanostructure via a low temperature<br> hydrothermal process. Zinc nitrate tetrahydrate and hexamethylenetetramine precursors were<br> mixed into aquades and ultrasonically cleaned for 30 minutes before stirred and followed by<br> hydrothermal process at 95 C for 4 hours in an oven. Scanning electron microscope (SEM).<br> analysis showed the formation of hexagonal ZnO micro-nanorod structures with diameter range<br> from hundreds nanometers to several micrometers. XRD analysis revealed that the synthesized<br> ZnO has hexagonal crystal structure, belong to P63mc space group which was in coordination<br> with SEM analysis. It can be conclude that ZnO micro-nanorod structure can be produced via a<br> low temperature hydrothermal method by optimizing the synthesis parameter. ZnO also has<br> potential apllications in various fields, such as heavy metal remover and material for electri...
Dalam kajian ini, struktur komposit bola karbon – seng oksida (ZnO) disintesis menggunakan kombin... more Dalam kajian ini, struktur komposit bola karbon – seng oksida (ZnO) disintesis menggunakan kombinasi dari metode deposisi uap kimia termal dan rendaman sol – gel. Oli bekas digunakan sebagai prekursor alami untuk menghasilkan bola karbon menggunakan pemanas deposisi uap kimia termal 2 tahap. Mikroskop elektron, dispersi energi sinar-X dan spektroskopi mikro-Raman digunakan untuk mengetahui struktural dan sifat sampel. Gambar mikroskop elektron menunjukkan struktur ZnO yang termodifikasi setelah dikompositkan dengan bola karbon. Berkurangnya diameter batang ZnO juga teramati di beberapa bagian sampel. Karakteristik arus – tegangan dengan dan tanpa pencahayaan UV diukur menggunakan simulator sel surya. Didapatkan bahwa dengan pencahayaan UV, karakteristik arus – tegangan dari sampel bola karbon – ZnO meningkat. Sifat pancaran medan elektron sampel juga dipelajari dan didapatkan medan <em>turn on</em> yang rendah (2,1 V/mm pada 1,0 mA/cm<sup>2</sup>) dengan rapa...
Synthesis of carbon nanotubes with different concentrations of ferrocene (C<sub>10</sub&... more Synthesis of carbon nanotubes with different concentrations of ferrocene (C<sub>10</sub>H<sub>10</sub>Fe) as catalyst (5.33, 10.66, 13.99-19.99 wt%) from waste engine oil precursor has been done to study its effects on the growth of carbon nanotubes. Thermal chemical vapor deposition method was used in this study. The synthesis process lasted for 30 minutes under argon gas ambient in constant precursor vaporization and synthesis temperature of 450°C and 750°C respectively. The characterization of prepared samples were done using field emission scanning electron microscopy, micro-Raman spectroscopy and thermogravimetric analysis. High density carbon nanotubes was produced at 17.99 wt% catalyst concentration with purity of 72%. The results show that the structure, diameter size and quality of carbon nanotubes are highly affected by the catalyst concentrations.
This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a c... more This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a carbon source and ferrocene as a catalyst. The method used in this study was thermal chemical vapor deposition. Several parametric studies were conducted in order to optimize the production of carbon materials from WEO. The parameters were synthesis temperatures, catalyst concentrations, precursor temperatures and volumes, synthesis times and different types of WEO. The samples were characterized using electron microscopy, energy dispersive X-ray, X-ray diffraction, micro-Raman spectroscopy and thermogravimetric analysis. Electrical and field emission properties of the selected samples were analyzed using four-point probe and field electron emission (FEE) measurements. The findings showed that two different structures of carbon materials namely carbon spheres (CS) and carbon nanotubes (CNTs) were succesfully synthesized from WEO. High density CS were produced from 3 ml of WEO mixed with 5...
This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a c... more This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a carbon source and ferrocene as a catalyst. The method used in this study was thermal chemical vapor deposition. Several parametric studies were conducted in order to optimize the production of carbon materials from WEO. The parameters were synthesis temperatures, catalyst concentrations, precursor temperatures and volumes, synthesis times and different types of WEO. The samples were characterized using electron microscopy, energy dispersive X-ray, X-ray diffraction, micro-Raman spectroscopy and thermogravimetric analysis. Electrical and field emission properties of the selected samples were analyzed using four-point probe and field electron emission (FEE) measurements. The findings showed that two different structures of carbon materials namely carbon spheres (CS) and carbon nanotubes (CNTs) were succesfully synthesized from WEO. High density CS were produced from 3 ml of WEO mixed with 5...
Carbon microspheres (C-mS) were successfully synthesized from used lube oil as the carbon source ... more Carbon microspheres (C-mS) were successfully synthesized from used lube oil as the carbon source using thermal chemical vapor deposition method. The nature present of carbon content in used lube oil promoted the growth of C-mS. The oil mixed with 5,33 wt% of ferrocene catalyst was initially heated at 450 °C in the precursor furnace and then transferred into deposition furnace at 900 °C by the flow of argon carrier gas. The collected sample was then analyzed using field emission scanning electron microscope (FESEM) and micro-Raman spectroscopy. The current-voltage ( IV ) profile of the C-mS was also studied using four-point probe measurement. FESEM and micro-Raman analyses showed the production of high density C-mS with diameter range of 0,57 – 3,14 mm and I D / I G ratio of 0,95. Semiconductor characteristic was observed from IV measurement indicated that the C-mS synthesized from used lube oil has potential to be applied in electronic devices. This study noted that the used lube oi...
Transparent conductive films (TCFs) have been widely used as transparent electrodes in nanoelectr... more Transparent conductive films (TCFs) have been widely used as transparent electrodes in nanoelectronic and energy storage devices. An ideal electrode should have high optical transparency, electrical conductivity and carrier mobility to increase the performance and efficiency of devices. Graphene is introduced as a promising new-generation material for the fabrication of transparent electrodes because of its unique electrical, optical and mechanical properties. Consistent efforts, such as the synthesis and transfer of graphene, have been exerted to produce excellent transparent electrodes. This article presents the methods that have been used to produce graphene, such as chemical vapour deposition, solution processing and chemical reduction. In addition, the benefits and drawbacks of several transfer techniques, such as chemical etching from a metal substrate, roll-to-roll process, spin coating, dip coating, drop casting and spray coating, are briefly discussed. For instance, the transfer of graphene for TCF preparation remains challenging. The potential applications of graphene-based TCFs, such as in flexible displays, solar cells, supercapacitors, transistors and electrochromic films, are also discussed.
Micro-nanorod structures of zinc oxide (ZnO) have been successfully synthesized via a simple and ... more Micro-nanorod structures of zinc oxide (ZnO) have been successfully synthesized via a simple and low-cost hydrothermal method. ZnO solutions with different concentrations of 0.05 and 0.1 M were prepared using zinc nitrate tetrahydrate and hexamethylenetetramine precursors. They were dissolved in aquades and stirred before the hydrothermal process at 95 C for 4 hours in an oven. Extensive characterizations using scanning electron microscope (SEM) and Xray diffraction (XRD) were conducted on ZnO powder samples. SEM results showed that hexagonally shaped ZnO micro-nanorods were formed with diameters ranging from hundreds of nanometers to several micrometers. The ZnO sample synthesized at 0.05 M was observed to have a better surface morphological structure than the 0.1 M sample. In addition, XRD measurements confirmed that samples exhibited a hexagonal crystal structure of ZnO. Moreover, the calculated crystallite sizes of ZnO using the Debye-Scherrer equation using the full-width half maxima of the XRD peaks were 25.153 nm for the 0.05 M sample and 28.707 nm for the 0.1 M sample. The most prominent growth of ZnO had 101 plane orientation or nonpolar a-plane followed by nonpolar 100 m-plane and 002 polar c-plane orientations. This study offers a simple and low-cost route to produce high-quality ZnO micro-nanorods for use in various electrical and optical devices. Abstrak Kajian Morfologi dan Struktural Batang Mikro-nano ZnO Disintesis Menggunakan Metode Hidrotermal dengan Biaya Rendah. Struktur batang mikro-nano seng oksida (ZnO) berhasil disintesis menggunakan metode hidrotermal sederhana dan dengan biaya yang rendah. Larutan ZnO dengan konsentrasi berbeda yaitu 0,05 dan 0,1 M disiapkan menggunakan prekursor seng nitrat tetrahidrat dan heksamethilentetramin. Prekursor tersebut dilarutkan di dalam akuades dan diaduk sebelum proses hidrotermal berlangsung pada suhu 95 C selama 4 jam di dalam oven. Sampel serbuk ZnO dikarakterisasi secara ekstensif menggunakan mikroskop elektron (SEM) dan difraksi sinar-x (XRD). Hasil analisis SEM menunjukkan bahwa batang mikro-nano ZnO berbentuk heksagonal dihasilkan dengan rentang diameter dari ratusan nanometer hingga beberapa mikrometer. Sampel ZnO yang disintesis dengan konsentrasi 0,05 M teramati memiliki struktur morfologi yang lebih baik dibandingkan sampel 0,1 M. Pengukuran XRD mengkonfirmasi bahwa sampel sesuai dengan ZnO dengan struktur kristal heksagonal. Lebih lanjut, perhitungan estimasi rata-rata ukuran kristal ZnO menggunakan persamaan Debye-Scherrer dengan puncak XRD lebar penuh pada setengah maksimum didapat yaitu sebesar 25,153 nm untuk sampel 0,05 M dan 28,707 nm untuk sampel 0,1 M. Pertumbuhan ZnO paling dominan yaitu pada orientasi bidang 101 atau bidang nonpolar a diikuti orientasi bidang nonpolar m 100 dan bidang polar c 002. Kajian ini menawarkan metode yang simpel dan dengan biaya rendah untuk menghasilkan batang mikronano ZnO yang memiliki potensi untuk diaplikasikan dalam berbagai peralatan elektronik dan optik.
Merkuri (Hg) merupakan logam berat yang berbahaya bagi tubuh apabila keberadaannya melebihi amban... more Merkuri (Hg) merupakan logam berat yang berbahaya bagi tubuh apabila keberadaannya melebihi ambang batas. Penentuan Hg telah banyak dilakukan salah satunya dengan menggunakan instrumen AAS (Atomic Absorption Spectrophotometry). Pada penelitian ini, analisis kandungan Hg dari daun singkong dilakukan dengan menggunakan SS AAS (Solid Sampling Atomic Absorption Spectrophotometry) di mana sampel dalam bentuk padatan. Preparasi sampel daun singkong dilakukan dengan menggunakan alat freeze dryer, sebuah alat pengering pada suhu rendah. Dari data percobaan diperoleh nilai akurasi sebesar 98,65% dan presisi sebesar 98,34%, batas deteksi 0,00029 ng/g. Konsentrasi Hg yang diperoleh di sampel daun singkong sebesar 335,069 ng/g dengan nilai ketidakpastian relatif sebesar 3,7274 ng/g dan nilai ketidakpastian diperluas sebesar 7,4548 ng/g.
To cite this article: Aisyah, A. N. et al. (2018). Effect of frequency and number of piezoelectri... more To cite this article: Aisyah, A. N. et al. (2018). Effect of frequency and number of piezoelectric probes in sonication-assisted exfoliation of graphite layers into graphene oxide.
IOP Conference Series: Materials Science and Engineering, 2018
One of the strategies used to facilitate assessment and instructional media implementation is by ... more One of the strategies used to facilitate assessment and instructional media implementation is by using information and communication technology in learning. The main objective of this study was to develop adaptive learning module with Android-based eassessment. This study employed DDD-E Model (Decide, Design, Develop, and Evaluate). The result was android-based e-assessment adaptive multimedia applicable in learning process. The system used Kotlin programming language. The advantage of this media is that it is integrated with the cloud service so that it can synchronize itself in realtime and can be accessed anywhere and anytime; it holds many multimedia formats; and it is equipped with its main assessment system with formative and summative functions.
Rapid progress in nanotechnology requires the production of novel nanomaterials. This study aims ... more Rapid progress in nanotechnology requires the production of novel nanomaterials. This study aims to synthesize Graphene Oxide (GO) via the Liquid Exfoliation (LE) method using a self-custom-made tweeter piezoelectric system as the ultrasound generator. Linear Alkylbenzena Sulfonate (LAS) surfactant contained in commercial detergent is used to assist the exfoliation process. This synthesis method is simple, inexpensive and may produce GO in a large quantity. Furthermore, the effect of the sonication time on the synthesis of GO is studied. The UV-Vis spectrophotometer and Scanning Electron Microscope (SEM) are used to characterize the synthesis results. UV-Vis analysis shows that the longer the sonication time spent, the thinner the GO layers produced. Moreover, images from SEM show that the surface morphology of the GO forms transparent layers which are stacked together on top of each other.
This research aims i) to determine the density profile and calculate the ground state energy of a... more This research aims i) to determine the density profile and calculate the ground state energy of a quantum dot in two dimensions (2D) with a harmonic oscillator potential using orbital-free density functional theory, and ii) to understand the effect of the harmonic oscillator potential strength on the electron density profiles in the quantum dot. This study determines the total energy functional of the quantum dot that is a functional of the density that depends only on spatial variables. The total energy functional consists of three terms. The first term is the kinetic energy functional, which is the Thomas-Fermi approximation in this case. The second term is the external potential. The harmonic oscillator potential is used in this study. The last term is the electron-electron interactions described by the Coulomb interaction. The functional is formally solved to obtain the electron density as a function of spatial variables. This equation cannot be solved analytically, and thus a numerical method is used to determine the profile of the electron density. Using the electron density profiles, the ground state energy of the quantum dot in 2D can be calculated. The ground state energies obtained are 2.
Research innovation in finding new carbon sources for carbon nanostructures material production w... more Research innovation in finding new carbon sources for carbon nanostructures material production was intensively done lately. In this review, we present the production of carbon nanostructures such as carbon fibers, nanotubes, nanowhiskers, microspheres and porous carbon from several waste materials. The benefit of the use of waste materials such as waste cooking palm oil, chicken fat, waste natural oil, glycerol, printed circuit board, plastic wastes, waste engine oil, scrap tyre, heavy oil residue and deoiled asphalt is not only in the term of their environmentally friendly approach but also the economic value to reduce the high cost of carbon material production using common sources. On the other hand, these materials are easy access sources and can be alternative utilization to convert waste materials into high value nanomaterials.
Abstract For the first time, amorphous aluminium–copper (Al–Cu) alloy nanowires decorated with ca... more Abstract For the first time, amorphous aluminium–copper (Al–Cu) alloy nanowires decorated with carbon spheres (CS) were synthesised from waste engine oil (WEO) as a starting material. The synthesis process was carried out in two-stage thermal chemical vapour deposition system under typical synthesis condition of 5.33 wt% ferrocene as catalyst, precursor and synthesis temperature of 450 and 700 °C, respectively. Metal contaminants of Al and Cu in WEO promote the growth of amorphous Al–Cu alloy nanowires and high carbon content in WEO undeniable promotes the growth of CS. Field emission scanning electron microscopy analysis showed that the amorphous Al–Cu alloy nanowires dimension was about 120 nm in diameter and a few micrometres in length, while the diameter of CS were a few hundred nanometre to micrometre-sized. X-ray diffraction pattern of amorphous Al–Cu alloy nanowires revealed the formation of different Al–Cu phases. This study offers a new and simple technique to synthesise amorphous Al–Cu alloy nanowires decorated with CS from waste material namely WEO. The newly produced nanomaterials open up potential application in energy storage devices.
For the first time, zinc oxide (ZnO) nanoflowers on ZnO nanorods were produced on carbon nanotube... more For the first time, zinc oxide (ZnO) nanoflowers on ZnO nanorods were produced on carbon nanotubes (CNTs) synthesised from waste cooking palm oil precursor. First, CNTs were grown using thermal chemical vapour deposition method. Next, ZnO nanostructures were deposited using the sonicated sol-gel immersion method and the prepared samples were characterised using electron microscopy, micro-Raman spectroscopy and X-ray diffraction. The field electron emission properties of the samples indicated that the ZnO nanoflowers grown on the CNTs had better emission performances than the pristine aligned ZnO nanorods. The resulting CNTs/ZnO nanocomposite had reasonable turn-on and threshold fields of 4.6 and 6.7 V/µ m, which corresponded with the electric fields required to create current densities of 1.0 µ A/cm 2 and 0.1 mA/cm 2 , respectively. This study shows the important roles of CNTs in ZnO nanoflowers growth and the abilities of CNTs to enhance ZnO emission properties.
Quasi-aligned carbon nanotubes (CNTs) were successfully synthesised for the first time using wast... more Quasi-aligned carbon nanotubes (CNTs) were successfully synthesised for the first time using waste engine oil (WEO) as the carbon source via thermal chemical vapour deposition (TCVD). The high carbon content of WEO was believed to promote the growth of the quasi-aligned CNTs. The synthesis process was performed at precursor and synthesis temperatures of 500 and 750 1C, respectively, with a ferrocene catalyst concentration of 17.99 wt%. Typical characterisation methods were employed to examine the CNTs: electron microscopy, energy dispersive X-Ray, X-ray diffraction and micro-Raman spectroscopy. The ability of CNT samples to emit electrons was also investigated by field electron emission (FEE) analysis. Electron microscopy and micro-Raman analysis revealed a dense mixture of quasi-aligned single-and multi-walled CNTs with a moderate I D /I G ratio of 0.90. The overall diameters of the CNTs ranged from 18.0 to 29.8 nm, with the diameters of the single-walled CNTs estimated to be between 0.6 and 1.1 nm. The FEE results showed that the quasi-aligned CNTs synthesised from WEO exhibited reasonable turn-on and threshold fields of 4.1 and 7.2 V μm À 1 , which corresponded to current densities of 0.1 and 1.0 μA cm À 2 , respectively. This study highlights WEO as a new, cheap, abundant and easily available carbon source for quasi-aligned CNTs production with a potential application in electron emission devices.
Various methods have been introduced to synthesize ZnO nanostructures, however as in most nanomat... more Various methods have been introduced to synthesize ZnO nanostructures, however as in most nanomaterial fabrication processes, these methods require sophisticated equipment and relatively high cost. Hydrothermal method has been known as a simple and inexpensive route to produce ZnO nanostructures. Unfortunately, this method takes a long production time in order to produce high quality ZnO hence making it less efficient. In this study, ZnO micro-nano structures have been successfully synthesized via a fast and low wattage microwave-assisted hydrothermal growth. X-ray diffraction and scanning electron microscope characterizations were done on samples. The rapid heating process generated from rotation, friction and collisions of water molecules inside the microwave resulted in faster reaction process compared with conventional hydrothermal method. Due to its time and cost efficient, this method is useful for optimizing the resulted ZnO and its further applications.
Based on the 2014 Regional Autonomy Law, the implementation of legal metrology in the form of cal... more Based on the 2014 Regional Autonomy Law, the implementation of legal metrology in the form of calibration, re-calibration and supervision is now the authority of the district/city. This study is expected to provide information related to legal metrology in general and particularly the importance of implementing metrological supervision in the regions. This research was conducted with a qualitative approach with the method of literature review and case studies in Bangka Selatan Regency. The low number of Measuring, Dosing, Weighing Equipment and Their Equipment (UTTP) and Packaged Goods (BDKT) in accordance with the provisions of the legislation is the main factor that causes the importance of this metrological supervision activity to be carried out, in addition to the low level of public understanding or knowledge regarding metrology. legal. In the end, effective metrological monitoring activities can help create an Orderly Measurement Area that is able to provide protection to cons...
This research aimed to produce zinc oxide (ZnO) nanostructure via a low temperature<br> hyd... more This research aimed to produce zinc oxide (ZnO) nanostructure via a low temperature<br> hydrothermal process. Zinc nitrate tetrahydrate and hexamethylenetetramine precursors were<br> mixed into aquades and ultrasonically cleaned for 30 minutes before stirred and followed by<br> hydrothermal process at 95 C for 4 hours in an oven. Scanning electron microscope (SEM).<br> analysis showed the formation of hexagonal ZnO micro-nanorod structures with diameter range<br> from hundreds nanometers to several micrometers. XRD analysis revealed that the synthesized<br> ZnO has hexagonal crystal structure, belong to P63mc space group which was in coordination<br> with SEM analysis. It can be conclude that ZnO micro-nanorod structure can be produced via a<br> low temperature hydrothermal method by optimizing the synthesis parameter. ZnO also has<br> potential apllications in various fields, such as heavy metal remover and material for electri...
Dalam kajian ini, struktur komposit bola karbon – seng oksida (ZnO) disintesis menggunakan kombin... more Dalam kajian ini, struktur komposit bola karbon – seng oksida (ZnO) disintesis menggunakan kombinasi dari metode deposisi uap kimia termal dan rendaman sol – gel. Oli bekas digunakan sebagai prekursor alami untuk menghasilkan bola karbon menggunakan pemanas deposisi uap kimia termal 2 tahap. Mikroskop elektron, dispersi energi sinar-X dan spektroskopi mikro-Raman digunakan untuk mengetahui struktural dan sifat sampel. Gambar mikroskop elektron menunjukkan struktur ZnO yang termodifikasi setelah dikompositkan dengan bola karbon. Berkurangnya diameter batang ZnO juga teramati di beberapa bagian sampel. Karakteristik arus – tegangan dengan dan tanpa pencahayaan UV diukur menggunakan simulator sel surya. Didapatkan bahwa dengan pencahayaan UV, karakteristik arus – tegangan dari sampel bola karbon – ZnO meningkat. Sifat pancaran medan elektron sampel juga dipelajari dan didapatkan medan <em>turn on</em> yang rendah (2,1 V/mm pada 1,0 mA/cm<sup>2</sup>) dengan rapa...
Synthesis of carbon nanotubes with different concentrations of ferrocene (C<sub>10</sub&... more Synthesis of carbon nanotubes with different concentrations of ferrocene (C<sub>10</sub>H<sub>10</sub>Fe) as catalyst (5.33, 10.66, 13.99-19.99 wt%) from waste engine oil precursor has been done to study its effects on the growth of carbon nanotubes. Thermal chemical vapor deposition method was used in this study. The synthesis process lasted for 30 minutes under argon gas ambient in constant precursor vaporization and synthesis temperature of 450°C and 750°C respectively. The characterization of prepared samples were done using field emission scanning electron microscopy, micro-Raman spectroscopy and thermogravimetric analysis. High density carbon nanotubes was produced at 17.99 wt% catalyst concentration with purity of 72%. The results show that the structure, diameter size and quality of carbon nanotubes are highly affected by the catalyst concentrations.
This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a c... more This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a carbon source and ferrocene as a catalyst. The method used in this study was thermal chemical vapor deposition. Several parametric studies were conducted in order to optimize the production of carbon materials from WEO. The parameters were synthesis temperatures, catalyst concentrations, precursor temperatures and volumes, synthesis times and different types of WEO. The samples were characterized using electron microscopy, energy dispersive X-ray, X-ray diffraction, micro-Raman spectroscopy and thermogravimetric analysis. Electrical and field emission properties of the selected samples were analyzed using four-point probe and field electron emission (FEE) measurements. The findings showed that two different structures of carbon materials namely carbon spheres (CS) and carbon nanotubes (CNTs) were succesfully synthesized from WEO. High density CS were produced from 3 ml of WEO mixed with 5...
This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a c... more This study aimed to synthesize carbon nanostructured materials from waste engine oil (WEO) as a carbon source and ferrocene as a catalyst. The method used in this study was thermal chemical vapor deposition. Several parametric studies were conducted in order to optimize the production of carbon materials from WEO. The parameters were synthesis temperatures, catalyst concentrations, precursor temperatures and volumes, synthesis times and different types of WEO. The samples were characterized using electron microscopy, energy dispersive X-ray, X-ray diffraction, micro-Raman spectroscopy and thermogravimetric analysis. Electrical and field emission properties of the selected samples were analyzed using four-point probe and field electron emission (FEE) measurements. The findings showed that two different structures of carbon materials namely carbon spheres (CS) and carbon nanotubes (CNTs) were succesfully synthesized from WEO. High density CS were produced from 3 ml of WEO mixed with 5...
Carbon microspheres (C-mS) were successfully synthesized from used lube oil as the carbon source ... more Carbon microspheres (C-mS) were successfully synthesized from used lube oil as the carbon source using thermal chemical vapor deposition method. The nature present of carbon content in used lube oil promoted the growth of C-mS. The oil mixed with 5,33 wt% of ferrocene catalyst was initially heated at 450 °C in the precursor furnace and then transferred into deposition furnace at 900 °C by the flow of argon carrier gas. The collected sample was then analyzed using field emission scanning electron microscope (FESEM) and micro-Raman spectroscopy. The current-voltage ( IV ) profile of the C-mS was also studied using four-point probe measurement. FESEM and micro-Raman analyses showed the production of high density C-mS with diameter range of 0,57 – 3,14 mm and I D / I G ratio of 0,95. Semiconductor characteristic was observed from IV measurement indicated that the C-mS synthesized from used lube oil has potential to be applied in electronic devices. This study noted that the used lube oi...
Transparent conductive films (TCFs) have been widely used as transparent electrodes in nanoelectr... more Transparent conductive films (TCFs) have been widely used as transparent electrodes in nanoelectronic and energy storage devices. An ideal electrode should have high optical transparency, electrical conductivity and carrier mobility to increase the performance and efficiency of devices. Graphene is introduced as a promising new-generation material for the fabrication of transparent electrodes because of its unique electrical, optical and mechanical properties. Consistent efforts, such as the synthesis and transfer of graphene, have been exerted to produce excellent transparent electrodes. This article presents the methods that have been used to produce graphene, such as chemical vapour deposition, solution processing and chemical reduction. In addition, the benefits and drawbacks of several transfer techniques, such as chemical etching from a metal substrate, roll-to-roll process, spin coating, dip coating, drop casting and spray coating, are briefly discussed. For instance, the transfer of graphene for TCF preparation remains challenging. The potential applications of graphene-based TCFs, such as in flexible displays, solar cells, supercapacitors, transistors and electrochromic films, are also discussed.
Micro-nanorod structures of zinc oxide (ZnO) have been successfully synthesized via a simple and ... more Micro-nanorod structures of zinc oxide (ZnO) have been successfully synthesized via a simple and low-cost hydrothermal method. ZnO solutions with different concentrations of 0.05 and 0.1 M were prepared using zinc nitrate tetrahydrate and hexamethylenetetramine precursors. They were dissolved in aquades and stirred before the hydrothermal process at 95 C for 4 hours in an oven. Extensive characterizations using scanning electron microscope (SEM) and Xray diffraction (XRD) were conducted on ZnO powder samples. SEM results showed that hexagonally shaped ZnO micro-nanorods were formed with diameters ranging from hundreds of nanometers to several micrometers. The ZnO sample synthesized at 0.05 M was observed to have a better surface morphological structure than the 0.1 M sample. In addition, XRD measurements confirmed that samples exhibited a hexagonal crystal structure of ZnO. Moreover, the calculated crystallite sizes of ZnO using the Debye-Scherrer equation using the full-width half maxima of the XRD peaks were 25.153 nm for the 0.05 M sample and 28.707 nm for the 0.1 M sample. The most prominent growth of ZnO had 101 plane orientation or nonpolar a-plane followed by nonpolar 100 m-plane and 002 polar c-plane orientations. This study offers a simple and low-cost route to produce high-quality ZnO micro-nanorods for use in various electrical and optical devices. Abstrak Kajian Morfologi dan Struktural Batang Mikro-nano ZnO Disintesis Menggunakan Metode Hidrotermal dengan Biaya Rendah. Struktur batang mikro-nano seng oksida (ZnO) berhasil disintesis menggunakan metode hidrotermal sederhana dan dengan biaya yang rendah. Larutan ZnO dengan konsentrasi berbeda yaitu 0,05 dan 0,1 M disiapkan menggunakan prekursor seng nitrat tetrahidrat dan heksamethilentetramin. Prekursor tersebut dilarutkan di dalam akuades dan diaduk sebelum proses hidrotermal berlangsung pada suhu 95 C selama 4 jam di dalam oven. Sampel serbuk ZnO dikarakterisasi secara ekstensif menggunakan mikroskop elektron (SEM) dan difraksi sinar-x (XRD). Hasil analisis SEM menunjukkan bahwa batang mikro-nano ZnO berbentuk heksagonal dihasilkan dengan rentang diameter dari ratusan nanometer hingga beberapa mikrometer. Sampel ZnO yang disintesis dengan konsentrasi 0,05 M teramati memiliki struktur morfologi yang lebih baik dibandingkan sampel 0,1 M. Pengukuran XRD mengkonfirmasi bahwa sampel sesuai dengan ZnO dengan struktur kristal heksagonal. Lebih lanjut, perhitungan estimasi rata-rata ukuran kristal ZnO menggunakan persamaan Debye-Scherrer dengan puncak XRD lebar penuh pada setengah maksimum didapat yaitu sebesar 25,153 nm untuk sampel 0,05 M dan 28,707 nm untuk sampel 0,1 M. Pertumbuhan ZnO paling dominan yaitu pada orientasi bidang 101 atau bidang nonpolar a diikuti orientasi bidang nonpolar m 100 dan bidang polar c 002. Kajian ini menawarkan metode yang simpel dan dengan biaya rendah untuk menghasilkan batang mikronano ZnO yang memiliki potensi untuk diaplikasikan dalam berbagai peralatan elektronik dan optik.
Merkuri (Hg) merupakan logam berat yang berbahaya bagi tubuh apabila keberadaannya melebihi amban... more Merkuri (Hg) merupakan logam berat yang berbahaya bagi tubuh apabila keberadaannya melebihi ambang batas. Penentuan Hg telah banyak dilakukan salah satunya dengan menggunakan instrumen AAS (Atomic Absorption Spectrophotometry). Pada penelitian ini, analisis kandungan Hg dari daun singkong dilakukan dengan menggunakan SS AAS (Solid Sampling Atomic Absorption Spectrophotometry) di mana sampel dalam bentuk padatan. Preparasi sampel daun singkong dilakukan dengan menggunakan alat freeze dryer, sebuah alat pengering pada suhu rendah. Dari data percobaan diperoleh nilai akurasi sebesar 98,65% dan presisi sebesar 98,34%, batas deteksi 0,00029 ng/g. Konsentrasi Hg yang diperoleh di sampel daun singkong sebesar 335,069 ng/g dengan nilai ketidakpastian relatif sebesar 3,7274 ng/g dan nilai ketidakpastian diperluas sebesar 7,4548 ng/g.
To cite this article: Aisyah, A. N. et al. (2018). Effect of frequency and number of piezoelectri... more To cite this article: Aisyah, A. N. et al. (2018). Effect of frequency and number of piezoelectric probes in sonication-assisted exfoliation of graphite layers into graphene oxide.
IOP Conference Series: Materials Science and Engineering, 2018
One of the strategies used to facilitate assessment and instructional media implementation is by ... more One of the strategies used to facilitate assessment and instructional media implementation is by using information and communication technology in learning. The main objective of this study was to develop adaptive learning module with Android-based eassessment. This study employed DDD-E Model (Decide, Design, Develop, and Evaluate). The result was android-based e-assessment adaptive multimedia applicable in learning process. The system used Kotlin programming language. The advantage of this media is that it is integrated with the cloud service so that it can synchronize itself in realtime and can be accessed anywhere and anytime; it holds many multimedia formats; and it is equipped with its main assessment system with formative and summative functions.
Rapid progress in nanotechnology requires the production of novel nanomaterials. This study aims ... more Rapid progress in nanotechnology requires the production of novel nanomaterials. This study aims to synthesize Graphene Oxide (GO) via the Liquid Exfoliation (LE) method using a self-custom-made tweeter piezoelectric system as the ultrasound generator. Linear Alkylbenzena Sulfonate (LAS) surfactant contained in commercial detergent is used to assist the exfoliation process. This synthesis method is simple, inexpensive and may produce GO in a large quantity. Furthermore, the effect of the sonication time on the synthesis of GO is studied. The UV-Vis spectrophotometer and Scanning Electron Microscope (SEM) are used to characterize the synthesis results. UV-Vis analysis shows that the longer the sonication time spent, the thinner the GO layers produced. Moreover, images from SEM show that the surface morphology of the GO forms transparent layers which are stacked together on top of each other.
This research aims i) to determine the density profile and calculate the ground state energy of a... more This research aims i) to determine the density profile and calculate the ground state energy of a quantum dot in two dimensions (2D) with a harmonic oscillator potential using orbital-free density functional theory, and ii) to understand the effect of the harmonic oscillator potential strength on the electron density profiles in the quantum dot. This study determines the total energy functional of the quantum dot that is a functional of the density that depends only on spatial variables. The total energy functional consists of three terms. The first term is the kinetic energy functional, which is the Thomas-Fermi approximation in this case. The second term is the external potential. The harmonic oscillator potential is used in this study. The last term is the electron-electron interactions described by the Coulomb interaction. The functional is formally solved to obtain the electron density as a function of spatial variables. This equation cannot be solved analytically, and thus a numerical method is used to determine the profile of the electron density. Using the electron density profiles, the ground state energy of the quantum dot in 2D can be calculated. The ground state energies obtained are 2.
Research innovation in finding new carbon sources for carbon nanostructures material production w... more Research innovation in finding new carbon sources for carbon nanostructures material production was intensively done lately. In this review, we present the production of carbon nanostructures such as carbon fibers, nanotubes, nanowhiskers, microspheres and porous carbon from several waste materials. The benefit of the use of waste materials such as waste cooking palm oil, chicken fat, waste natural oil, glycerol, printed circuit board, plastic wastes, waste engine oil, scrap tyre, heavy oil residue and deoiled asphalt is not only in the term of their environmentally friendly approach but also the economic value to reduce the high cost of carbon material production using common sources. On the other hand, these materials are easy access sources and can be alternative utilization to convert waste materials into high value nanomaterials.
Abstract For the first time, amorphous aluminium–copper (Al–Cu) alloy nanowires decorated with ca... more Abstract For the first time, amorphous aluminium–copper (Al–Cu) alloy nanowires decorated with carbon spheres (CS) were synthesised from waste engine oil (WEO) as a starting material. The synthesis process was carried out in two-stage thermal chemical vapour deposition system under typical synthesis condition of 5.33 wt% ferrocene as catalyst, precursor and synthesis temperature of 450 and 700 °C, respectively. Metal contaminants of Al and Cu in WEO promote the growth of amorphous Al–Cu alloy nanowires and high carbon content in WEO undeniable promotes the growth of CS. Field emission scanning electron microscopy analysis showed that the amorphous Al–Cu alloy nanowires dimension was about 120 nm in diameter and a few micrometres in length, while the diameter of CS were a few hundred nanometre to micrometre-sized. X-ray diffraction pattern of amorphous Al–Cu alloy nanowires revealed the formation of different Al–Cu phases. This study offers a new and simple technique to synthesise amorphous Al–Cu alloy nanowires decorated with CS from waste material namely WEO. The newly produced nanomaterials open up potential application in energy storage devices.
For the first time, zinc oxide (ZnO) nanoflowers on ZnO nanorods were produced on carbon nanotube... more For the first time, zinc oxide (ZnO) nanoflowers on ZnO nanorods were produced on carbon nanotubes (CNTs) synthesised from waste cooking palm oil precursor. First, CNTs were grown using thermal chemical vapour deposition method. Next, ZnO nanostructures were deposited using the sonicated sol-gel immersion method and the prepared samples were characterised using electron microscopy, micro-Raman spectroscopy and X-ray diffraction. The field electron emission properties of the samples indicated that the ZnO nanoflowers grown on the CNTs had better emission performances than the pristine aligned ZnO nanorods. The resulting CNTs/ZnO nanocomposite had reasonable turn-on and threshold fields of 4.6 and 6.7 V/µ m, which corresponded with the electric fields required to create current densities of 1.0 µ A/cm 2 and 0.1 mA/cm 2 , respectively. This study shows the important roles of CNTs in ZnO nanoflowers growth and the abilities of CNTs to enhance ZnO emission properties.
Quasi-aligned carbon nanotubes (CNTs) were successfully synthesised for the first time using wast... more Quasi-aligned carbon nanotubes (CNTs) were successfully synthesised for the first time using waste engine oil (WEO) as the carbon source via thermal chemical vapour deposition (TCVD). The high carbon content of WEO was believed to promote the growth of the quasi-aligned CNTs. The synthesis process was performed at precursor and synthesis temperatures of 500 and 750 1C, respectively, with a ferrocene catalyst concentration of 17.99 wt%. Typical characterisation methods were employed to examine the CNTs: electron microscopy, energy dispersive X-Ray, X-ray diffraction and micro-Raman spectroscopy. The ability of CNT samples to emit electrons was also investigated by field electron emission (FEE) analysis. Electron microscopy and micro-Raman analysis revealed a dense mixture of quasi-aligned single-and multi-walled CNTs with a moderate I D /I G ratio of 0.90. The overall diameters of the CNTs ranged from 18.0 to 29.8 nm, with the diameters of the single-walled CNTs estimated to be between 0.6 and 1.1 nm. The FEE results showed that the quasi-aligned CNTs synthesised from WEO exhibited reasonable turn-on and threshold fields of 4.1 and 7.2 V μm À 1 , which corresponded to current densities of 0.1 and 1.0 μA cm À 2 , respectively. This study highlights WEO as a new, cheap, abundant and easily available carbon source for quasi-aligned CNTs production with a potential application in electron emission devices.
Various methods have been introduced to synthesize ZnO nanostructures, however as in most nanomat... more Various methods have been introduced to synthesize ZnO nanostructures, however as in most nanomaterial fabrication processes, these methods require sophisticated equipment and relatively high cost. Hydrothermal method has been known as a simple and inexpensive route to produce ZnO nanostructures. Unfortunately, this method takes a long production time in order to produce high quality ZnO hence making it less efficient. In this study, ZnO micro-nano structures have been successfully synthesized via a fast and low wattage microwave-assisted hydrothermal growth. X-ray diffraction and scanning electron microscope characterizations were done on samples. The rapid heating process generated from rotation, friction and collisions of water molecules inside the microwave resulted in faster reaction process compared with conventional hydrothermal method. Due to its time and cost efficient, this method is useful for optimizing the resulted ZnO and its further applications.
Analisis Difraksi Sinar-X (X-ray Diffraction) merupakan metode karakterisasi material yang diguna... more Analisis Difraksi Sinar-X (X-ray Diffraction) merupakan metode karakterisasi material yang digunakan untuk mengidentifikasi fase kristalin material dengan cara menentukan parameter struktur kisi serta untuk mendapatkan ukuran partikel
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mengidentifikasi fase kristalin material dengan cara menentukan parameter struktur kisi serta untuk mendapatkan
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