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"In this work, Myrmecodia pendans, or sarang semut, was successfully extracted as a potential organic inhibitor. Various concentrations of Myrmecodia pendans extract in 1 M H2SO4 solution were applied in the range of 100?500 mg/L for corrosion inhibition. Gas chromatography?mass spectroscopy (GC-MS) showed that the Myrmecodia pendans extracts contained a high-benzenediol compound with rich oxygen atom content, which played an important role in the inhibition process. The 300 mg/L Myrmecodia pendans extract had the highest effect, decreasing the rate of corrosion from 177.73 mpy to 47.4 mpy. This was attributed to the chemical compounds present in the Myrmecodia pendans extract on the surface of mild steel, which prohibited the corrosion rate"

"In this work, Myrmecodia pendans, or sarang semut, was successfully extracted as a potential organic inhibitor. Various concentrations of Myrmecodia pendans extract in 1 M H2SO4 solution were applied in the range of 100–500 mg/L for corrosion inhibition. Gas chromatography–mass spectroscopy (GC-MS) showed that the Myrmecodia pendans extracts contained a high-benzenediol compound with rich oxygen atom content, which played an important role in the inhibition process. The 300 mg/L Myrmecodia pendans extract had the highest effect, decreasing the rate of corrosion from 177.73 mpy to 47.4 mpy. This was attributed to the chemical compounds present in the Myrmecodia pendans extract on the surface of mild steel, which prohibited the corrosion rate."

"Inhibition is one of themechanisms used for mitigating the metallic corrosion, particularly in an acid environment. The present work aims toinvestigate theinhibiting effect of N-benzyl-N/-phenyl thiourea (BPTU) on thecorrosion of low carbon steel in a 0.1 M hydrochloric acid (HCl) solution using a Tafelextrapolation and linear polarization techniques. The study reveals that BPTUacts as an excellent anodic inhibitor for low carbon steel in a HClsolution. The protective efficiency of the compound was found to be more than97% even at higher temperatures. The study demonstrated that BPTU gets adsorbedon the steel surface, following Temkin?s adsorption isotherm and the inhibitionis controlled by a chemisorptionmechanism. The investigation shows that the results obtained from the Tafelextrapolation and linear polarization techniques for the corrosion of mildsteel in HCl medium were in good agreement. The influence of temperatures andconcentrations of BPTU on the corrosion of low carbon steel are alsoexamined in the present work."

"Pada proses pre-commisioning jaringan pipa bawah laut diperlukan pencegahan korosi dimana laju korosi material baja API 5L grade B di dalam larutan 3,5 % NaCl teraerasi pada kondisi steady masih relatif tinggi yang dapat mencapai lebih dari 20 mpy (0,5 mm/tahun). Upaya pencegahan korosi pada saat proses hydrotest dengan media air laut dilakukan dengan penambahan inhibitor anorganik yang mengandung zat corrosion inhibitor, oxygen scavenger dan biocide sehingga diperlukan bahan organik alternatif ramah lingkungan dengan kinerja yang lebih baik. Tujuan utama dari penelitian ini adalah untuk menginvestigasi efisiensi dari penggunaan campuran ekstrak sarang semut dan sirih merah sebagai alternatif inhibitor ramah lingkungan atau bahan campuran untuk mengurangi penggunaan inhibitor anorganik pada perlindungan korosi material baja API 5L Grade B dalam lingkungan 3,5% NaCl.Kemampuan inhibisi korosi dari hasil ekstrak bahan alami diinvestigasi dengan menggunakan pengujian Tafel polarisasi dan Electrochemical Impedance Spectroscopy (EIS) serta diverifikasi dengan pengujian kehilangan berat. Kandungan senyawa aktif dalam ekstrak sarang semut dan sirih merah beserta senyawa teradsorpsi pada permukaan logam dan mekaniseme inhibisi elektrokimia diinvestigasi dengan pengujian EIS, FTIR dan model adsorpsi isoterm. Pada konsentrasi campuran green inhibitor 2ml sarang semut + 1ml sirih merah, effisiensi inhibitor dapat mencapai 73,66%. Pada penggunaan sebagai inhibitor campuran dengan inhibitor kimia pada konsentrasi campuran 1ml kimia + 2ml green inhibitor, dapat menurunkan laju korosi secara signifikan dari 0,42 mm/year menjadi 0,03 mm/year dengan efisiensi mencapai 93,15%. Inhibitor korosi tersebut berpengaruh terhadap kurva polarisasi anodik maupun katodik sehingga dapat berperan sebagai mixed inhibitor.Pengujian FTIR menunjukan adanya gugus-gugus fungsi ikatan kimia yang berkombinasi sebagai pembentuk lapisan (film forming) seperti Gugus hidroksil, karbonil, aromatik, alkane dan amina. Adsorpsi senyawa-senyawa terkandung dalam inhibitor sarang semut dan sirih merah pada permukaan logam terjadi spontan mengikuti Langmuir adsorpsi isoterm. Hasil ini sesuai dengan hipotesis awal bahwa ekstrak sarang semut dan sirih merah yang mengandung senyawa antioksidan dapat mencegah proses oksidasi pada permukaan logam sehingga akan mengurangi laju korosi.

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During pre-commissioning of subsea pipeline are require corrosion prevention since the corrosion rate of steel material of API 5L grade B in 3.5% NaCl aerated solution under steady state condition is still relatively high (can reach more than 0,5 mm/year). Method to prevent the corrosion during subsea pipeline hydrotest using seawater is generally by the addition of inorganic inhibitor containing corrosion inhibitor agent, oxygen scavenger and biocide, so that require to find out the alternative eco- friendly materials with better performance. The main objective of this study is to investigate the efficiency of the use of mixture of extract of myrmecodia pendans and piper crocatum as an alternative of eco-friendly inhibitor or a compound for reducing the use of inorganic inhibitors for corrosion protection of steel material API 5L Grade B in 3,5% NaCl Environmental.

The corrosion inhibition ability of natural ingredient extraction are investigated by using tafel polarization test and electrochemical impedance spectroscopy (EIS) and verified by weight loss test. The content of the active compounds in the extract of Myrmecodia Pendans and Piper Crocatum along with adsorption compound on metal surfaces and electrochemical inhibition mekaniseme are investigated by EIS, FTIR testing and model of the Langmuir adsorption isotherm. The addition of mixed green inhibitor concentration of 2ml myrmecodia pendans and 1ml piper crocatum is resulted in approximately 73.66% inhibitor efficiency while the addition of mixed green inhibitor into chemical inhibitor with concentration of 1ml for chemical and 2ml for green inhibitor are significantly reduce the corrosion rate from 0.42 mm/year to be 0.03 mm/year with approximately 93.15% inhibitor efficiency.

The green inhibitor affected the cathodic as well as the anodic polarization curves which were known as mixed corrosion inhibitor type. The type of chemical bonds on the steel surface layer was analyzed by FTIR method which indicated hydroxyl, carbonyl, aromatic, alkane and amine group. The adsorption of compounds contained in the myrmecodia pendans and piper crocatum inhibitor on a metal surface are occur spontaneously follows the Langmuir adsorption isotherm. These results are consistent with the initial hypothesis that the extract of myrmecodia pendans and piper crocatum contains antioxidant compound which can prevent the oxidation process in the metal surface thereby will reducing the corrosion rate."

"The growth and crystallization processes of the Cu2ZnSnS4 (CZTS) phase typically rely on high-temperature sulfurization, which involves a harmful chalcogen-containing atmosphere. Together with the use of high-toxicity solvents, these processes could hinder the widespread adoption of this technology in the mass production of CZTS semiconductors for solar cell application. Thus, we studied the formation of CZTS films from ethanol-based precursors without the sulfurization step, fully employing the non-toxic solvent and avoiding the environmentally harmful sulfur-containing atmosphere. The certain addition of 2-mercaptopropionic acid led to the formation of a clear and stable sulfur-containing precursor. The precursors were successfully deposited onto soda lime glass by employing spin coater. CZTS crystallinity in the identified XRD patterns was vanishingly small in the case of eliminating the sulfurization process. Moreover, the carbon concentration and grain size of the resulting films were controlled by changing the time period of drying treatment during film fabrication. A drying time of 120 minutes, which demonstrated a CZTS grain size of ± 1 µm with a direct optical energy gap around 1.4 eV, was confirmed as the ideal condition. These results may provide a useful route toward environment-friendly strategies for the production of a CZTS semiconductor that is compatible with the absorber application in thin-film solar cells."

"Thedevelopment of the construction industry in Indonesia has been substantiallycontributing to the enhancement of the social and economic development of thepeople. However, its expansion has also become an issue, as the developmentmight be implicated in the abuse of environmental sustainability when thepractices of conducting the construction project abandon the rules and regulationsof sustainable green construction concepts. Therefore, this study attempted tointroduce a quantitative assessment tool called the Green Construction SiteIndex (GCSI) to evaluate the performance of an ongoing project to meet thesustainable green construction concept. The aim of this study was toinvestigate the effectiveness of GCSI as a quantitative assessment tool tomeasure the implementation of the green construction concept conducted byongoing projects. Data were collected by onsite direct observation, interviewswith key personnel, and project documentation review. Data were organized andanalyzed using descriptive elaboration. The results showed that three aspects,the Efficiency Index (IE), Productivity Index (IP), andAwareness Index (IA), were effective in assessing 10 ongoingconstruction projects, categorized as Non-Commercial Non-Residential Building,Commercial Residential Building, and Commercial Non-Residential Building. Theindex generated using GCSI, upon assessing 10 buildings, was 3.39 and fell intothe Good category with IE = 3.51, IP = of 2.86, and IA= 3.84. Another finding shows that the Project Organizational CommitmentIndex (POCI) to the indicator ofthe GCSI was 3.31 (Good category) with IPOL = 3.36, IPRO =3.49, and IPRAC = 2.75. The capability of the GCSI to identify threeaspects within a construction project simultaneously and comprehensivelysuggests the importance of its function as an effective tool that givesbenefits to not only the contactors, but also to the authorities that controlthe green construction?related performance. Therefore, the GCSI is expected tobe applied as a standardized reference by both the construction industries andregulating authorities. Despite its satisfactory findings, the GCSI needs to befurthered to achieve its reliability and validity to be adopted internationally."

"Cold formedsteel has relatively high width-to-thickness ratio elements, which causes it tobuckle easily. Combining it with timber laminas would be an effective solutionfor reducing this buckling problem. This research focuses on the connectionsystem of a cold formed steel-timber composite, which was obtainedby attaching several timber laminas to the web part of cold formedsteel using screws. The connection used two bolts that were 8 mm in diameter,as well as two different kinds of side plates: steel and plywood. Cold formedsteel 75Z08 and Swietenia mahagoni(moisture content 12.2%; specific gravity 0.77) were used for connections andwere loaded in parallel and perpendicular directions. In addition, theconnections of cold formed steel (without timber laminas) usingself-drilling screw fasteners were tested until failure. Numerical analysispredicting the load-slip curve and apparent yield load of the composite joints wascarried out using the DOWEL program and the European Yield Theory,respectively. The test results showed that the connection system with steelside plates is capable of accommodating the strength increase of compositemember, as it has a maximum load carrying capacity and initial slip modulus ofabout 4.5 and 2 times larger than those of the cold formed steel connections, respectively. In the caseof a connection system with plywood side plates, its joint properties aresimilar to those of the cold formed steel connection, except that it has largerjoint deformation."

"Ballast is one of themain structures for the railway tracks. It can resist the lateral movementunder dynamic loading transferred by the passing trains with repeatedly. Undersome circumstances, ballast can suffer degradation or breakdown due to therepeated loading and maintenance. Ballast is easily exposed to the weatherbecause it is laid on the track. Acid rain affects the performance of therailway track near the industrial and urbanarea. As a result, it starts to foul and the small chips from ballast filledthe void, as well as reduce the shear strength of ballast particles. Thissituation can contribute into the increasing of maintenance frequency andcosting. This paper examines the potential of rubber inclusions in increasingthe shear resistance of rubber-ballast composites in simulated water and acid soakedconditions with several configuration. This lab-based exploratory work is only static load simulation in conventional shear boxsetup measuring 60 mm × 60 mm.The aggregates size is 10 times smaller than actual size of ballast. In orderto identify the shear resistance deterioration of rubber-aggregates mixtureunder poor drainage conditions by soaked a batch of aggregates in water andacid solution for 2 weeks to simulate accelerated weathering effects. The shearresistance did not rise dramatically with the rubber reinforcement. Thissusceptible shear strain plots indicate ductile behaviour on theaggregates-rubber composites. This is evident by the linear rise of shearstress with strain up to approximately 10% for the control samples (CS) untilit reaches a constant value. Note that all the specimens including CS are in aloose state during the testing because there were no tamping been applied onthe samples. Overall the circular patch (CP) specimen was the most favourablethan the other configurations. Both mechanisms contributed to the reducedoverall subsistence, accompanied by an increase in the shear resistance. Theinclusion of rubber elements apparently prevented the dilation of the granularmaterial when approaching the shear failure and the reducing the settlement."

"Cylindrical uranium dioxide pellets, which are the main components for nuclear fuel elements in light water reactors, should have a high density profile, a uniform shape, and a minimum standard quality for their safe use as a reactor fuel component. The quality of green pellets is conventionally monitored by laboratory measurement of the physical pellet characteristics; however, this conventional classification method shows some drawbacks, such as difficult usage, low accuracy, and high time consumption. In addition, the method does not address the non-linearity and complexity of the relationship between pellet quality variables and pellet quality. This paper presents the development and application of a modified Radial Basis Function neural network (RBF NN) as an automatic classification system for green pellet quality. The weight initialization of the neural networks in this modified RBF NN is calculated through an orthogonal least squared method, and in conjunction with the use of a sigmoid activation function on its output neurons. Experimental data confirm that the developed modified RBF NN shows higher recognition capability when compared with that of the conventional RBF NNs. Further experimental results show that optimizing the quality classification problem space through eigen decomposition method provides a higher recognition rate with up to 98% accuracy."

"This study was aimed todetermine the reaction stoichiometry between Cu(II) and di-2-ethylhexylphosphoricacid (D2EHPA) in Waste Palm CookingOil (WPCO). The stoichiometry was computed based onthe followingexperimentalmethods, namely slope analysis, loading test and Job?smethod. Slope analysis was used to measure the variation of the distribution coefficient"