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PENGONTROLAN RETAK PADA BETON DENGAN OPTIMALISASI INTERAKSI KOMPOSIT BETON PADA INTERFACE ZONE Muin, Resmi Bestari; Alva, Sagir; Patty, Agnes Hanna; Fidi, Fidi; Arianti, Adelfy Dara
Jurnal Teknik Sipil Vol 27, No 1 (2020)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2020.27.1.7

AbstrakStudi ini melakukan kajian yang signifikan terhadap kemungkinan terjadinya retak awal dan perambatannya yang rentan terjadi pada struktur-struktur di daerah marine. Retak beton yang terjadi merambat terutama di sepanjang interface zone yang secara signifikan dikondisikan oleh karakteristik agregat. Karakteristik agregat sebagai pengisi beton memiliki peran signifikan sebagai media pelepasan energi regangan dan dikenal sebagai energi fraktur. Hubungan energi fraktur dengan sifat material belum diidentifikasi secara jelas, dan sebagian besar studi menunjukkan ketidakpekaan relatif terhadap faktor air-semen, di mana retakan beton merambat terutama di sepanjang antarmuka agregat-semen. Penelitian ini merupakan penelitian eksperimental tentang karakteristik fraktur beton dengan variasi gradasi agregat kasar diameter maksimum 25 mm dan 20 mm, serta variasi faktor air-semen (w/c rasio) 0,30, 0,40 dan 0,6 dengan diameter maksimum agregat kasar 19 mm. Eksperimen meliputi uji kuat tekan dan uji parameter fraktur yang terdiri dari energi fraktur dan faktor intensitas tegangan. Tes lentur tiga titik dipilih berdasarkan rekomendasi RILEM untuk menghitung parameter fraktur.Hasil penelitian menunjukkan bahwa gradasi agregat yang digunakan dalam campuran beton mempengaruhi energi fraktur beton. Energi puncak tertinggi didapat dengan menggunakan gradasi agregat menerus. Ukuran maksimum agregat mempunyai pengaruh yang signifikan terhadap energi fraktur. Semakin besar ukuran maksimum agregat dalam campuran beton, semakin tinggi energi puncak yang dicapai. Gradasi seragam dengan ukuran maksimum yang lebih kecil memiliki nilai kuat tekan yang tinggi namun energi fraktur yang rendah. Kuat tekan meningkat dengan menurunnya w/c rasio air-semen, sedangkan energi fraktur tidak memberikan pola yang sama dengan kuat tekan dengan perubahan w/c rasio. AbstractThis study conducts a significant study of the possibility of initial cracking and its propagation, which is susceptible to concrete structures. Concrete cracks that occur propagate mainly along the interface (interface zone) which is significantly influenced by the cement water factor and aggregate characteristics, as a concrete filler have a significant role as a strain energy release media known as fracture energy (GF). The relationship of fracture energy to material properties has not been clearly identified, besides that most studies show a relative insensitivity to the water-cement factor, where concrete cracks propagate mainly along the aggregate-cement interface. This study is an experimental study of the characteristics of concrete fractures with variations in coarse aggregate gradations, namely uniform coarse gradations with the maximum diameter of 25 mm (25 S) and 20 mm (20 S); continuous coarse aggregate with the maximum diameter of 25 mm (25 M), as well as variations in the water-cement factor (w / c ratio): 0.30 (HSC); 0.40 (MSC) and 0.6 (NSC) with a coarse aggregate maximum diameter of 19 mm. Experiments include compressive strength tests and concrete fracture property tests consisting of fracture energy

Performance of D-galactose for Protecting The Corrosion Rate of Aluminium Alloy 5052 (AA5052) in Acidic Environment I Gusti Ayu Arwati; Sagir Alva; Wahyu Irwansyah; Ibdal Satar
CHEMICA: Jurnal Teknik Kimia Vol 8, No 2 (2021): December 2021
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26555/chemica.v8i2.22195

The PEMFC systems are generally operated in acidic environment conditions. Consequently, the metal bipolar plate in the system can easily be corroded. Therefore, the PEMFC performance is decreased along with long-term operation. Based on this fact, a mitigation approach is needed to prevent the corrosion issue in the metal bipolar plate to maintain the PEMFC performance. This work tries to evaluate the corrosion rate of the aluminium bipolar plate before and after being deposited with D-galactose. The electrophoretic deposition (EPD) technique was used to deposit D-galactose on the aluminum surface. To evaluate the effect of D-galactose on preventing the corrosion rate, it was deposited on the surface of the aluminium (AA5052) bipolar plate. The EPD processes were performed by using a potensiodimic in 0.5 M H2SO4. The results show that the optimum EPD process condition was obtained at 0.5 g/l D-galactose for 20 minutes of electrophoretic deposition time. This work indicated that the D-galactose could reduce the corrosion rate of aluminium bipolar plate with an efficiency of 90.7%.

Pengontrolan Retak pada Beton dengan Optimalisasi Interaksi Komposit Beton pada Interface Zone Resmi Bestari Muin; Sagir Alva; Agnes Hanna Patty; Fidi Fidi; Adelfy Dara Arianti
Jurnal Teknik Sipil Vol 27 No 1 (2020)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2020.27.1.7

AbstrakStudi ini melakukan kajian yang signifikan terhadap kemungkinan terjadinya retak awal dan perambatannya yang rentan terjadi pada struktur-struktur di daerah marine. Retak beton yang terjadi merambat terutama di sepanjang interface zone yang secara signifikan dikondisikan oleh karakteristik agregat. Karakteristik agregat sebagai pengisi beton memiliki peran signifikan sebagai media pelepasan energi regangan dan dikenal sebagai energi fraktur. Hubungan energi fraktur dengan sifat material belum diidentifikasi secara jelas, dan sebagian besar studi menunjukkan ketidakpekaan relatif terhadap faktor air-semen, di mana retakan beton merambat terutama di sepanjang antarmuka agregat-semen. Penelitian ini merupakan penelitian eksperimental tentang karakteristik fraktur beton dengan variasi gradasi agregat kasar diameter maksimum 25 mm dan 20 mm, serta variasi faktor air-semen (w/c rasio) 0,30, 0,40 dan 0,6 dengan diameter maksimum agregat kasar 19 mm. Eksperimen meliputi uji kuat tekan dan uji parameter fraktur yang terdiri dari energi fraktur dan faktor intensitas tegangan. Tes lentur tiga titik dipilih berdasarkan rekomendasi RILEM untuk menghitung parameter fraktur.Hasil penelitian menunjukkan bahwa gradasi agregat yang digunakan dalam campuran beton mempengaruhi energi fraktur beton. Energi puncak tertinggi didapat dengan menggunakan gradasi agregat menerus. Ukuran maksimum agregat mempunyai pengaruh yang signifikan terhadap energi fraktur. Semakin besar ukuran maksimum agregat dalam campuran beton, semakin tinggi energi puncak yang dicapai. Gradasi seragam dengan ukuran maksimum yang lebih kecil memiliki nilai kuat tekan yang tinggi namun energi fraktur yang rendah. Kuat tekan meningkat dengan menurunnya w/c rasio air-semen, sedangkan energi fraktur tidak memberikan pola yang sama dengan kuat tekan dengan perubahan w/c rasio. AbstractThis study conducts a significant study of the possibility of initial cracking and its propagation, which is susceptible to concrete structures. Concrete cracks that occur propagate mainly along the interface (interface zone) which is significantly influenced by the cement water factor and aggregate characteristics, as a concrete filler have a significant role as a strain energy release media known as fracture energy (GF). The relationship of fracture energy to material properties has not been clearly identified, besides that most studies show a relative insensitivity to the water-cement factor, where concrete cracks propagate mainly along the aggregate-cement interface. This study is an experimental study of the characteristics of concrete fractures with variations in coarse aggregate gradations, namely uniform coarse gradations with the maximum diameter of 25 mm (25 S) and 20 mm (20 S); continuous coarse aggregate with the maximum diameter of 25 mm (25 M), as well as variations in the water-cement factor (w / c ratio): 0.30 (HSC); 0.40 (MSC) and 0.6 (NSC) with a coarse aggregate maximum diameter of 19 mm. Experiments include compressive strength tests and concrete fracture property tests consisting of fracture energy

STUDI DAN KARAKTERISASI LAJU KOROSI LOGAM ALUMINIUM DENGAN PELAPISAN MEMBRAN SOL-GEL Rohadi Satrio Budi Utomo; Sagir Alva
Jurnal Teknik Mesin Vol 6, No 3 (2017)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/jtm.v6i3.1969

Dari beberapa logam seperti baja, tembaga, seng, aluminium dan paduannya, maka aluminium memiliki keunggulan, terutama dalam hal ketahanan terhadap korosi. Ketahanan korosi yang sangat baik oleh aluminium disebabkan oleh adanya lapisan oksida tipis yang menempel sangat kuat di permukaannya (Al2O3). Lapisan Al2O3 stabil pada lingkungan pH 4 s/d pH 9 (pasifasi) sehingga lapisan tersebut dapat melindungi logam bagian dalam dari serangan korosi lanjutan, namun aluminium dapat juga terkorosi dalam lingkungan yang agresif yaitu di luar kisaran pH tersebut terutama suasana asam maupun basa. Hal ini dapat diatasi dengan memberikan coating berupa cat logam terhadap aluminium. Akan tetapi pemberian cat logam tidak dapat dilakukan pada situasi tertentu yang mengharuskan adanya reaksi antara logam dengan lingkungan asam ataupun basa dengan tetap mempertimbangkan ketahan korosi material tersebut, seperti yang terjadi pada baterai. Ini dikarenakan sifat cat yang membendung reaksi antara logam dengan lingkungannya. Oleh karena itu diperlukan penambahan inhibitor korosi dengan mempertimbangkan faktor di atas, yaitu dengan pelapisan membran Sol-Gel. Dari hasil pengujian Sol-Gel yang dilapisi pada aluminium mampu menahan laju korosi pada larutan HCl sebesar 24,26% dan larutan Asam Asetat sebesar 25,57% dibandingkan aluminium tanpa pelapisan. Kemudian membran Sol-Gel juga membuat lapisan pelindung laju korosi yang memiliki pori-pori dengan lebar celah ± 0,56 – 1,12 µm pada pengujian dengan larutan HCl dan ± 0,47 – 1,41 µm pada pengujian dengan larutan Asam Asetat sebagai jalan terjadinya reaksi antara logam dan cairan asam atau basa.

Analisis Potensi Limbah Logam/Kaleng, Studi Kasus di Keluarahan Meruya Selatan, Jakarta Barat Rini Anggraini; Sagir Alva; Popy Yuliarty; Teddy Kurniawan
Jurnal Teknik Mesin Vol 7, No 2 (2018)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/jtm.v7i2.3022

Sampah atau limbah padat merupakan material sisa yang dapat memberikan dampak negative karena dapat merusak lingkungan, tetapi juga dapat memberikan dampak positif apabila dikelola dengan teknik tertentu. Limbah logam merupakan limbah yang mudah dipisahkan dari timbunan sampah dan dapat didaur ulang menjadi barang – barang yang bernilai seni, dilebur kembali sebagai menjadi material asalnya, dan juga dapat dimanfaatkan sebagai campuran semen dan sebagainya.Penelitian ini bertujuan untuk mengetahui potensi limbah logam yang ada di Kelurahan Meruya Selatan Jakarta Barat. Penelitian dilakukan dengan melakukan observasi ke lokasi penelitian, melakukan wawancara dengan pihak-pihak yang terkait dengan penelitian dan dengan menyebarkan kuesioner. Sedangkan untuk mengetahui potensi limbah logam di wilayah penelitian, menggunakan analisa teknik analisa data berkala. Hasil penelitian menunjukkan bahwa jumlah limbah logam yang terkumpul di Bank Sampah RW 4 dan RW 9 Kelurahan Meruya Selatan menunjukkan kenaikan selama tahun 2016 dan 2017, meskipun dari segi kuantitas jumlahnya kecil. Hasil analisa trend untuk limbah besi adalah Y = - 2,005 + 0,69X, untuk limbah aluminium Y = - 0,6765 + 0,183X , untuk limbah kaleng Y = 2,0169 + 0,0042X , dan untuk total limbah logam Y = - 0,71 + 0,0042X. Dimana Y merupakan variabel jumlah limbah dan X merupakan variabel waktu.

CHLORIDE SENSOR FABRICATION BASED ON SPE Ag/AgCl THROUGH CYCLIC VOLTAMMETRIC TECHNIQUE: SCAN RATE EFFECT Mas'ud Asadullah; Sagir Alva; Ali Rinaldi; Rita Sundari
SINERGI Vol 25, No 3 (2021)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2021.3.012

The Cyclic Voltammetric (CV) technique is one of the Ag/AgCl fabrication processes. In electrochemical processes using this CV technique, the microstructure of the surface of a substrate or electrode can affect the scan rate. Thus, this study aims to identify the scan rate effect of the Cl-ion sensor fabrication process using the CV technique on the performance of the Cl-ion sensor. First, the CV process was carried out in one cycle to grow the AgCl layer on the Ag surface. Then, this process was carried out at varied scan rates of 20, 40, 60, 80, and 100 mV/s. After completing the Ag/AgCl fabrication process, it was followed by the characterization process, selectivity coefficient test, lifetime test, and validation test to compare the test results of the Cl SPE Ag/AgCl ion sensor with Ag/AgCl commercial. The results showed that the optimum Cl-ion sensor response was obtained at the scan rate of 60 mV/s. Then, based on the validation test, the Cl-ion in the two samples did not show significant differences. Therefore, it indicates that the SPE Ag/AgCl ion sensor has the same performance as the Ag/AgCl commercial.

TIRE WASTE AS A POTENTIAL MATERIAL FOR CARBON ELECTRODE FABRICATION: A REVIEW Ahmad Ariri; Sagir Alva; Siti Aishah Hasbullah
SINERGI Vol 25, No 1 (2021)
Publisher : Universitas Mercu Buana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22441/sinergi.2021.1.001

Nowadays, tire waste is a big issue since the rapid growth of vehicle population worldwide. The disposal of tire waste should be done properly due to the environmental impact caused by stockpile the tire waste in landfill. Many kinds of research had been conducted to dispose of tire waste efficiently for getting valuable material from tire waste by using pyrolysis technology; one of them is carbon. In this review paper, production and application of carbon from tire waste presented. In several studies, carbon derived from tire waste was used as an adsorbent, electrode in energy storage application, like batteries and fuel cell.

Closed-Horizontal Rotating Burner Development for Optimizing Plam Shell Charcoal (PSC) Production Dafit Feriyanto; Supaat Zakaria; Sagir Alva; Hadi Pranoto; Andi Firdaus Sudarma; Albert Phak Jie Wong
International Journal of Advanced Technology Vol 1, No 2 (2020)
Publisher : Institute for Research on Innovation and Industrial System (IRIS)

Activated Carbon (AC) was produced through several stages such as carbonization, crushing and activation process. The critical part of AC production was located at carbonization process due to burner issues that need to complete burning in short time, appropriate temperature and low cost. Therefore, this research focus on developing burner which called by closed-horizontal rotating burner. The dimension of the burner was 65 x 790 mm (D x L) wih the capacity of 30 kg/carbonization process. This burner need 1 hour for complete burning of palm shell to palm shell charcoal (PSC). Several analysis were conducted such as stress, displacement, factor of safety and thermal analysis. because this burner involved in rotation motion and high temperature operation. Physical properties has been measured which consists of moisture content (3.8-5%), ash content (7.7-8%), volatile content (53.7-56.6%) and fixed carbon content (31.3-34.7%). It can be summarized that this burner was very effective to produce PSC with short time carbonization process, low cost and complete charcoal production.

Ag/AgCl Reference Electrode Based on Thin Film of Arabic Gum Membrane Sagir Alva; Aiman Sajidah binti Abdul Aziz; Mohd Ismahadi bin Syono; Wan Adil bin Wan Jamil
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

The Ag/AgCl reference electrode based on the Arabic Gum (AG) hydrogel films was successfully developed. The Arabic Gum concentration used in this study was 10–40% (w/v) with an optimum concentration of 20% (w/v). In this study, reference electrode performance testing is based on DmV response of Cl-ion’s measurements, stability tests and performance testing against ISE sensors such as K+, NH4+, and NO3-. The Ag/AgCl based reference electrode of the Arabic Gum film shows an average DmV of 4.0 ± 0.7 mV when response test is performed against a standard Ag/AgCl double junction electrode in various concentrations of Cl-ion’s. Meanwhile, in stability testing conducted in a 0.01 M KCl solution for 72 h found drift of < 0.6 mV/h. The reference performance test of the Arabic Gum reference electrode with three types of ISE NH4+, K+ and NO3- commercial sensors obtaining a slope closer to the Nernst value is 54.9 ± 0.9, 52.3 ± 0.5 and -53.2 ± 0.2 mV/dec with all having a linear distance of 0.1–10-5 M.

Preliminary Study of Poly(Tetrahydrofurfuryl Acrylate) Thin Film as a Potential Material of Ion Selective Electrodes: The Case of Nitrate Ion-Selective Electrode Sagir Alva; Robi Suherman; Vivi Friliandita; Deni Shidqi Khaerudini; Edy Herianto Majlan; Aiman Sajidah Abd Aziz
Indonesian Journal of Chemistry Vol 20, No 3 (2020)
Publisher : Universitas Gadjah Mada

A preliminary study on the use of a photocurable poly-tetrahydrofurfuryl acrylate (pTHFA) has been successfully performed as an alternative membrane for application in the Ion-Selective Electrode (ISE) sensors such as Nitrate-ISE. The pTHFA membrane was synthesized using photopolymerization technique and further optimized by varying the concentration of the photo-initiator. The pTHFA photopolymer was characterized by C-NMR, H-NMR, FTIR, and DSC. The best sensing formulation comprising pTHFA photopolymer was obtained from composition II with Tg of -17.3 °C. In the Nitrate-ISE fabrication process, initially, the tetraoctylammonium nitrate (TOAN) ionophore was optimized. The optimum TOAN concentration of 4.2 mg was then immobilized onto composition II as a sensing matrix. Results showed that the pTHFA based ISE sensor exhibited a slope near the Nernstian number with a good linear response for detecting nitrate ion concentration between 10–1 to 10–4 M (r2 = 0.9994) and limit of detection as low as 3.47 × 10–5 M. Furthermore, the selectivity behavior of pTHFA based nitrate-ISE sensor was determined in various types of interfering ions such as SO42–, H2PO4–, HPO42–, Cl– and I–. The sensor has demonstrated selectivity coefficient of -2.27 ± 0.2, -2.49 ± 0.6, -2.18 ± 0.8, -1.31 ± 0.1 and 0.41 ± 0.2, respectively. The fabricated pTHFA ISE-Nitrate sensor was further tested in the fish ponds, soils, and also rivers. The sensors have shown excellent performance and is comparable to the standard method.

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