Articles
            
            
            
            
            
                            
                    
                        Energi Alternatif Melalui Getaran Beban Mekanis 
                    
                    Dimas Ramadhan Putra; 
Jhav Sund Oktoricoento; 
Sahrudin Sahrudin; 
Mohammad Mujirudin; 
Harry Ramza; 
Oktarina Heriyani; 
Akhiruddin Maddu                    
                     Prosiding Seminar Nasional Teknoka Vol 3 (2018): Prosiding Seminar Nasional Teknoka ke - 3 
                    
                    Publisher : Fakultas Teknik, Universitas Muhammadiyah Prof. Dr. Hamka, Jakarta 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                    |
                            
                            
                                Full PDF (674.289 KB)
                            
                                                                                    
                            | 
                                DOI: 10.22236/teknoka.v3i0.2802                            
                                            
                    
                        
                            
                            
                                
Electricity needs increase over time. Electricity is a very important requirement that is used to facilitate human life, for example for lighting at night, running household appliances and for various other human works. This research was carried out by making a small-scale prototype model which was measured by Digital Multimeter DT830B series.The data obtained from the testing of piezoelectric sensors showed that when compiled in series, the highest output power was 19.4888 μW with a maximum load of 186 kg, while for the preparation of sensors in parallel the resulting power reached 61.5043 μW from a load of 186 kg as an indication of the mechanical load vibration provided.
                            
                         
                     
                 
                
                            
                    
                        Immobilization of Glucose Oxidase on Modified-Carbon-Paste-Electrodes for Microfuel Cell 
                    
                    Laksmi Ambarsari; 
Inda Setyawati; 
Rini Kurniasih; 
Popi Asri Kurniatin; 
Akhiruddin Maddu                    
                     Indonesian Journal of Chemistry Vol 16, No 1 (2016) 
                    
                    Publisher : Universitas Gadjah Mada 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                    |
                            
                            
                                Full PDF (368.241 KB)
                            
                                                                                    
                            | 
                                DOI: 10.22146/ijc.21183                            
                                            
                    
                        
                            
                            
                                
Glucose oxidase (GOx) is being developed for many applications such as an implantable fuel cell, due to its attractive property of operating under physiological conditions. This study reports the functional immobilization of glucose oxidase onto polyaniline-nanofiber-modified-carbon-paste-electrodes (GOx/MCPE) as bioanodes in fuel cell applications. In particular, GOx is immobilized onto the electrode surface via a linker molecule (glutaraldehyde). Polyaniline, synthesized by the interfacial polymerization method, produces a morphological form of nanofibers (100-120 nm) which have good conductivity. The performance of the polyaniline-modified-carbon-paste-electrode (MCPE) was better than the carbon- paste-electrode (CPE) alone. The optimal pH and temperature of the GOx/MCPE were 4.5 (in 100 mM acetate buffer) and 65 °C, respectively. The GOx/MCPE exhibit high catalytic performances (activation energy 16.4 kJ mol-1), have a high affinity for glucose (Km value 37.79 µM) and can have a maximum current (Imax) of 3.95 mA. The sensitivity of the bioelectrode also was high at 57.79 mA mM-1 cm-2.
                            
                         
                     
                 
                
                            
                    
                        Enhancing Ionic Conductivity of Carboxymethyl Cellulose-Lithium Perchlorate with Crosslinked Citric Acid as Solid Polymer Electrolytes for Lithium Polymer Batteries 
                    
                    Akhiruddin Maddu; 
Ahmad Sofyan Sulaeman; 
Setyanto Tri Wahyudi; 
Abdulloh Rifai                    
                     International Journal of Renewable Energy Development Vol 11, No 4 (2022): November 2022 
                    
                    Publisher : Center of Biomass & Renewable Energy, Diponegoro University 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                                    
                            | 
                                DOI: 10.14710/ijred.2022.40090                            
                                            
                    
                        
                            
                            
                                
Lithium batteries development are triggered so many efforts in producing electronic devices due to its excellent performance as energy storage systems. One of the appealing points solid polymer electrolytes for developing solid-state lithium batteries. In this study, Solid polymer electrolytes with crosslinked treatment (SPE-C) were prepared from carboxymethyl cellulose-lithium perchlorate (CMC-LiClO4) and citric acid (CA) as a crosslinker via solution casting method. All SPE-C membranes were assembled into lithium battery coin cells. Degree of crosslinked and degradation were measured to observe crosslink formation in SPE-C membranes and confirmed by fourier transform infrared (FTIR), whereas SPE-C in coin cells were characterized by electrochemical impedance spectroscopy (EIS) and linear sweep voltammograms (LSV). The results showed that crosslinked process is successfully obtained with C=O from ester linkage of CA vibration within COO- of CMC for the crosslinking bond formation. The crosslink effect also contributed on enhancing ionic conductivities of SPE-C in coin cells from EIS results. The highest ionic conductivity was obtained in SPE-C2 (1.24×10-7 S/cm) and electrochemically stable in 2.15 V based on LSV measurement. SPE-C2 has good dielectric behavior than the others due to the high ions mobilities for migration process from ion clusters formation, thus it would be useful for further study in obtaining the powerful solid-state lithium polymer batteries.
                            
                         
                     
                 
                
                            
                    
                        Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding 
                    
                    Maddu, Akhiruddin; 
Modjahidin, Kun; 
Sardy, Sar; 
Zain, Hamdani                    
                     Makara Journal of Technology Vol. 10, No. 1 
                    
                    Publisher : UI Scholars Hub 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                    
                    
                        
                            
                            
                                
Development of Fiber-Optic Humidity Sensor Probe with Gelatin Cladding. Humidity sensor based on optical fiber with gelatin cladding has been developed. In this humidity sensor probe, the origin cladding of optical fiber is replaced by gelatin coating as humidity sensitive cladding. Testing of the optical fiber sensor probe was conducted by measuring of light intensity transmitted on the optical fiber probe for each variation of different humidity treatments. Response of the optical fiber sensor probe measured from 42%RH to 99%RH, the results show an optical transmission curve varied with relative humidity (RH). Optical transmission in the optical fiber probe increase with RH value at a specific wavelength range, that is from green to red spectrum bands (500 nm – 700 nm), where a significant variation from 600 nm to 650 nm in yellow to red spectrum bands. Wavelength where is a maximum intensity of optical transmission occurs at 610 nm. Therefore, the optical fiber humidity sensor probe could response humidity form 42%RH to 99%RH with the best response in humidity range of 60%RH to 72%RH that is have a good linearity and sensitivity.
                            
                         
                     
                 
                
                            
                    
                        The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2 Solar Cell 
                    
                    Maddu, Akhiruddin; 
Zuhri, Mahfuddin; 
Irmansyah, Irmansyah                    
                     Makara Journal of Technology Vol. 11, No. 2 
                    
                    Publisher : UI Scholars Hub 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                    
                    
                        
                            
                            
                                
The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2 Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbage as photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwiching polymer electrolyte containing a redox couple (I-/I3 -). One of the electrodes, namely working electrode, TiO2 layer on TCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in the system. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethylene glycol) containing a redox couple (I-/I3 -) used instead of liquid electrolyte in this photoelectrochemical cell. Two fabricated cells have an active area of 1 cm2 were soaked with anthocyanine dye for 1 hr and 24 hrs, respectively. The cells were tested by irradiation with halogen lamp of 24 Watt with intensity 4 mW/cm2 at a distance 30 cm. The testing results of the cells show an ideal I-V characteristic with output parameters: open circuit voltage (VOC) of 500 mV, short circuit current (ISC) of 5,6 μA and 7,2 μA for each cells, fill factor (FF) of 48% for both cells, energy conversion (η) of 0.023 % and 0,055 % for the cells with 1 hr and 24 hrs dye soaked, respectively.
                            
                         
                     
                 
                
                            
                    
                        PEMANFAATAN KARBON AKTIF DARI BAMBU SEBAGAI ELEKTRODA SUPERKAPASITOR 
                    
                    Farly Tumimomor; 
Akhiruddin Maddu; 
Gustan Pari                    
                     JURNAL ILMIAH SAINS Volume 17 Nomor 1, April 2017 
                    
                    Publisher : Sam Ratulangi University 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                    |
                            
                            
                                Full PDF (433.516 KB)
                            
                                                                                    
                            | 
                                DOI: 10.35799/jis.17.1.2017.15802                            
                                            
                    
                        
                            
                            
                                
PEMANFAATAN KARBON AKTIF DARI BAMBU SEBAGAI ELEKTRODA SUPERKAPASITOR ABSTRAKPada penelitian ini, karbon aktif berbasis bambu telah digunakan untuk pembuatan superkapasitor. Uji daya jerap iodin dilakukan untuk mengukur tingkat serapan pori sampel karbon aktif yang ukurannya relatif kecil (mikropori). Karakteristik bahan karbon aktif yang meliputi struktur kristal dan morfologi permukaannya diuji dengan menggunakan SEM dan XRD. Bahan elektroda dengan komposisi (Karbon aktif : PVDF = 9:1 (b/b)), kolektor arus dan separator telah dirangkai untuk diuji kinerjanya sebagai perangkat penyimpanan muatan listrik. Metode siklik voltametri digunakan untuk melihat kinerja perangkat superkapasitor dengan mengukur nilai kapasitansi spesifik berdasarkan kurva voltammogram. Berdasarkan hasil perhitungan nilai kapasitansi spesifik diperoleh nilai kapasitansi spesifik tertinggi pada superkapasitor dengan elektroda bambu yang diaktivasi dengan steam 50 mL/bar yaitu sebesar  59.50 F.Kata kunci: Karbon aktif bambu, siklik voltametri, kapasitansi spesifik, superkapasitor.  UTILIZATION OF BAMBOO BASED ACTIVATED CARBON AS SUPERCAPACITOR ELECTRODE ABSTRACT In this study, bamboo based activated carbon has been used for fabrication of supercapacitors. Iodine absorption test is performed to measured absorption level porous activated carbon sample size is relatively small (microporous). Characteristics of the activated carbon material covering the surface morphology and structure were tested using SEM and XRD. Electrode materials with composition (Activated charcoal: PVDF = 9: 1 (w / w)), the current collector and separator has been assembled to be tested its performance as an electrical charge storage device. The test results by cyclic voltammetry method was to look at the performance supercapacitor devices at once to obtain the value of the capacitance curve obtained voltammograms. Based on the results of the calculation of the capacitance, the highest capacitance values obtained in the supercapacitor with activated carbon electrodes in bamboo steam 50 mL / bar with a capacitance value is 59.50 F / g.Keywords: Bamboo activated carbon, cyclic voltammetry, the specific capacitance, supercapacitor.
                            
                         
                     
                 
                
                            
                    
                        BIOMASSA SEBAGAI MATERIAL ELEKTRODA SUPERKAPASITOR 
                    
                    Nur Adi Saputra; 
Deded Sarip Nawawi; 
Akhiruddin Maddu; 
Gustan Pari; 
Wasrin Syafii                    
                     Jurnal Penelitian Hasil Hutan Vol 40, No 3 (2022): Jurnal Penelitian Hasil Hutan 
                    
                    Publisher : Pusat Penelitian dan Pengembangan Hasil Hutan 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                                    
                            | 
                                DOI: 10.20886/jphh.2022.40.3.189-202                            
                                            
                    
                        
                            
                            
                                
Piranti penyimpanan dan distribusi listrik akan menjadi sangat penting di masa depan untuk mengintegrasikan energi terbarukan ke dalam jaringan listrik. Teknologi superkapasitor dianggap sebagai alternatif yang paling menjanjikan untuk baterai Li-ion, yang memiliki bahan Lithium terbatas.. Namun, sifat kerapatan energi yang masih rendah menjadi kelemahan superkapasitor, walaupun memiliki kepadatan daya yang tinggi. Elektroda superkapasitor berbasis karbon aktif memiliki potensi ideal untuk dikembangkan. Atribut inheren karbon aktif, sifat pori dan gugus fungsi, bertanggung jawab dalam peningkatan kinerja superkapasitor. Tantangan utama para peneliti adalah distribusi ukuran pori, mikro (<2nm), meso (2 – 50 nm) dan makro (>50 nm), yang beragam pada karbon aktif. Pori mikro berdampak terhadap peningkatan nilai  kapasitansi spesifik yang akan mendorong peningkatan kepadatan energi. Pori meso berdampak terhadap aksesbilitas permukaan elektroda secara keseluruhan oleh ion elektrolit. Penelitian-penelitian ke depan akan lebih memperhatikan teknik karbonisasi dan aktivasi karbon aktif untuk meningkatkan kualitas permukaan karbon aktif.
                            
                         
                     
                 
                
                            
                    
                        KARAKTERISTIK SIFAT OPTIK NANOPARTIKEL KARBON (CARBON DOTS) DENGAN METODE UV-VIS DRS (ULTRAVIOLET-VISIBLE DIFFUSE REFLECTANCE SPECTROSCOPY) 
                    
                    Jumardin; 
Akhiruddin Maddu; 
Koekoeh Santoso; 
Isnaeni                    
                     JFT : Jurnal Fisika dan Terapannya Vol 9 No 1 (2022): JUNI 
                    
                    Publisher : Universitas Islam Negeri Alauddin Makassar 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                                    
                            | 
                                DOI: 10.24252/jft.v9i1.28815                            
                                            
                    
                        
                            
                            
                                
Research on the synthesis of Carbon Dots using the laser ablation method has been carried out at a time duration of 1, 2, and 3 hours (energy 60 mJ, wavelength 1064 nm and frequency 10 Hz). This research uses organic material from Tea and Toluene as the carbon solvent. The characterization method uses a UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS) spectrum to measure the reflectance value and uses the Kubelka-Munk equation to determine the relationship between the absorbance coefficient parameter (s) and the scattering reflectance coefficient (k). The size and morphological characterization methods used Particle Size Analyzer (PSA) and Transmission Electron Microscopy, while the functional group characteristics used the Fourier Transform InfraRed (FTIR) tool. FTIR spectra show the O-H group which is a hydroxyl bond and N-H is a carboxylic acid. The results of measurement and analysis of bandgap energy at different time durations for direct transition (n=2) were 1 hour (3.62 eV, 342.49 nm), 2 hours (3.24 eV, 380.61 nm) and 3 hours (2.74, 451.82 nm). Indirect transitions (n=1/2) were 1 hour (3.17 eV, 391.02 nm), 2 hours (2.50 eV, 495.36 nm) and 3 hours (2.21 eV, 559.04).
                            
                         
                     
                 
                
                            
                    
                        Synthesis and Characterization of Hydroxyapatite from Green Mussel Shell with Sol-Gel Method 
                    
                    Charlena Charlena; 
Akhiruddin Maddu; 
Tatang Hidayat                    
                     Jurnal Kimia Valensi Jurnal Kimia VALENSI Volume 8, No. 2, November 2022 
                    
                    Publisher : Syarif Hidayatullah State Islamic University 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                                    
                            | 
                                DOI: 10.15408/jkv.v8i2.27494                            
                                            
                    
                        
                            
                            
                                
Hydroxyapatite (HAp) is a major component of bones and teeth. HAp is widely used to repair, fill, extend, and reconstruct damaged bone tissue. HAp is used for bone and dental implants, so it is necessary to synthesize HAp. HAp synthesis can utilize green mussel shell waste as a calcium precursor. This research synthesized HAp from a green mussel shell using the sol-gel method. The controlled synthesis parameter was pH, and the variable being compared was the heating temperature at 900 and 1100 °C. The HAp products were characterized by an X-ray diffractometer (XRD), Fourier-transform infrared spectrophotometer, and scanning electron microscope. The results showed that HAp was formed at alkaline pH, namely at pH 11. The XRD pattern showed that Hap was formed along with type A apatite carbonate, octacalcium phosphate, α- and β-tricalcium phosphate. The crystallinity was increased by raising the temperature and prolonging the heating time. The quality of HAp will improve with increasing crystallinity, and increasing the temperature will also raise the amount of HAp formed.
                            
                         
                     
                 
                
                            
                    
                        BIOMASSA SEBAGAI MATERIAL ELEKTRODA SUPERKAPASITOR 
                    
                    Nur Adi Saputra; 
Deded Sarip Nawawi; 
Akhiruddin Maddu; 
Gustan Pari; 
Wasrin Syafii                    
                     Jurnal Penelitian Hasil Hutan Vol 40, No 3 (2022): Jurnal Penelitian Hasil Hutan 
                    
                    Publisher : Pusat Penelitian dan Pengembangan Hasil Hutan 
                    
                         Show Abstract
                        | 
                             Download Original
                        
                        | 
                            
                                Original Source
                            
                        
                        | 
                            
                                Check in Google Scholar
                            
                        
                                                                                    
                            | 
                                DOI: 10.20886/jphh.2022.40.3.189-202                            
                                            
                    
                        
                            
                            
                                
Piranti penyimpanan dan distribusi listrik akan menjadi sangat penting di masa depan untuk mengintegrasikan energi terbarukan ke dalam jaringan listrik. Teknologi superkapasitor dianggap sebagai alternatif yang paling menjanjikan untuk baterai Li-ion, yang memiliki bahan Lithium terbatas.. Namun, sifat kerapatan energi yang masih rendah menjadi kelemahan superkapasitor, walaupun memiliki kepadatan daya yang tinggi. Elektroda superkapasitor berbasis karbon aktif memiliki potensi ideal untuk dikembangkan. Atribut inheren karbon aktif, sifat pori dan gugus fungsi, bertanggung jawab dalam peningkatan kinerja superkapasitor. Tantangan utama para peneliti adalah distribusi ukuran pori, mikro (<2nm), meso (2 – 50 nm) dan makro (>50 nm), yang beragam pada karbon aktif. Pori mikro berdampak terhadap peningkatan nilai  kapasitansi spesifik yang akan mendorong peningkatan kepadatan energi. Pori meso berdampak terhadap aksesbilitas permukaan elektroda secara keseluruhan oleh ion elektrolit. Penelitian-penelitian ke depan akan lebih memperhatikan teknik karbonisasi dan aktivasi karbon aktif untuk meningkatkan kualitas permukaan karbon aktif.