Soil stabilization with bitumen emulsion and rubber latex

Imperial Users onl

Analisis Perbaikan Stern Tube Poros Propeller Single Screw pada Kapal General Cargo 4192 GT

Dalam proses perencanaan kapal, pada tahap pemasangan poros propulsi di kapal, tentu saja diperlukan penyelarasan yang benar. Kesalahan dapat menyebabkan distribusi beban yang tidak merata pada bantalan, akibatnya menyebabkan abrasi yang tidak normal, kondisi kelebihan beban, kelebihan beban dan kerusakan pada bagian bantalan tertentu, hal tersebut berlaku juga kepada struktur yang mendapat beban statis sebagai tumpuannya. perlunya uji numerik untuk proses analisa terjadinya beban berlebih dalam persiapan reparasi bantalan poros propeller sehingga menunjukan  karakter hidrodinamik dan beban yang terjadi ketika bantalan dan poros propeller mulai kontak. Tujuan penelitian ini,menganalisis desain bantalan poros propeller untuk direparasi dan untuk mendapatkan performa terbaik dari sistem kontak antara bantalan dengan poros propeller sehingga merepresentasikan perbandingan kinerja dari propeller sebelum dan sesudah perbaikan. Metode perhitungan dengan metode finite elemen berbasis persamaan matematik merepresentasikan tegangan yang terjadi sesuai karakter material bronze ( AlBr dan CuSn)  yang diaplikasikan pada performa bantalan proros propeller kapal tipe general cargo seberat 4192 GT. Hasil analisa menunjukan saat putaran propeller pada rpm mesin yang optimum, tegangan maksimum juga terjadi sesuai dengan hasil percobaan temperatur yang terjadi juga semakin tinggi. Pada beban rpm 525 maka shear stress untuk stern tube material AlBr bernilai 978 Mpa dan pada material SnCu bernilai 948 Mpa. Nilai deflect atau cleareance pada setiap posisi setelah dilakukan perbaikan mengalami peningkatan rata-rata sebesar 24,4 % dari pengukuran awal sebelum dilakukan reparasi. Proses reparasi menunjukan performa yang cukup baik, rata-rata temperatur kerja yang dihasilkan ketika dilakukan pengujian sea trial menurun dari sebelumnya sebesar 7,5%

Drying of Ionic Liquid

Room Temperature Ionic Liquids (RTILs) are salts in liquid phase. Continuous use of RTIL in a process may cause it to be contaminated with water and organic impurities over time. It is necessary to regenerate and purify the RTIL for recycle purposes. Drying is needed during pre-treatment and purification of IL solution before it can be used in any application to reduce weight, increase ease of handling and eliminate unwanted effects of moisture content towards IL properties. Drying process of ionic liquid is important since moisture levels that are too high may affect performance and reliability in most applications such as during synthesis of RTILs using aqueous solution to necessitate anion exchange and also in concentrating Benfield solution for recycles purposes during removal of CO2. Therefore, to obtain the most optimum condition of drying for ionic liquids, the study on kinetic of drying is reported here by investigate the effects of different operating temperature towards drying of ionic liquid, effect of different anion and cation and drying using different equipment. Ionic liquids containing [bmim] cation with [SO4]- or Phosphate-containing anion were used and drying methods applied were halogen lamp and vacuum drying methods. Thermogravimetric analysis which measures change of mass over time throughout the drying process was used to generate primary drying curves which were then manipulated to get secondary kinetic data. The drying process mainly occurred during falling rate period. Samples dried under higher temperature using vacuum drying have higher maximum drying rates, lower final moisture contents, higher drying constants and shorter drying times. The same result is observed for samples containing smaller anion

QUANTUM DO’A IBU: IMPLEMENTASI Q.S. ALI IMRAN: 35 DALAM MEMBENTUK KIDS ZAMAN NOW YANG BERKUALITAS

Doa merupakan senjata orang-orang beriman yang menjadi paramater kekuatan manusia serta mampu mengubah segalanya. Fenomena Kids Zaman Now, di mana kehidupan mereka dipandang negatif oleh masyarakat. Pembentukan karakter Kids Zaman Now yang berkualitas berbasis quantum doa ibu dapat dilakukan dengan mengikuti langkah-langkah berupa soa sejak dini, sejak dalam kandungan dan doa melalui nama. Kata Kunci: doa, kids zaman no

Antioxidant property from ziziphus mauritiana / Mohammad Hafiz Sulaiman

Ziziphus mauritiana or locally known in Malaysia as “Bidara” or “Epal Siam”are categorized as fruit tree species that commonly found in tropical and sub-tropical regions where each parts of Ziziphus mauritiana including its leaves, roots, and fruits have their own unique medicinal use for treatment of multiple kinds of diseases such as allergies and ulcers. This study aims to investigate the antioxidant property in different parts of Ziziphus mauritiana which are the leaves and stems that might be commercialized as sources of natural antioxidant. The total phenolic content (TPC) was determined by the Folin-Ciocalteu method and calibration curve with gallic acid as standard solution was plotted. While for the DPPH radical-scavenging activity of Ziziphus mauritiana was evaluated by using the formula to obtain the percentage of DPPH control. In this study, results showed a higher production of TPC in leaves than stems and higher in methanol than in chloroform. This is in conjunction with DPPH scavenging activity which is higher in leaves than in stems and also recorded higher in methanol than in chloroform

Analysis of corroded steel structures with local fatigue approaches

Offshore steel structures are exposed to harsh environmental conditions. At the same time, they are susceptible to fatigue due to cyclic loads from wind, waves, and operation as well as traffic. Both the steel structures and the corrosion protection have a limited lifetime. When the corrosion protection reaches the end of its service life, the steel is exposed to free corrosion. To continue the operation, the influence of corrosion on the fatigue behaviour has to be evaluated. Therefore, new methods need to be developed to accurately assess the actual condition of corroded components and integrate this information into (remaining) service life predictions. Motivated by these challenges, this work began with investigations on corroded steel plates (also referred to as base material). Initially, methods for capturing and numerically modelling the actual corroded condition were developed. A corroded steel surface was converted into a numerical model using a 3D scan, allowing the calculation of stress concentrations caused by corrosion. Subsequently, fatigue tests were conducted on pre-corroded steel samples. Prior to fatigue tests, the samples were 3D scanned to characterize the state of corrosion and determine the stress concentrations based on the real surface. It was demonstrated that the hotspots of stress concentrations correlated with the crack locations observed in the fatigue tests. To incorporate the stress concentrations into the fatigue analysis according to local fatigue concepts, various methods for considering the micro-support effect were investigated. The application of the implicit gradient model (IGM) yielded the most reliable results with the lowest scatter in the derived stress-life (SN) curve based on notch stresses. Using the parameters derived for the IGM and the corresponding notch stress SN-curve, a quantitative relationship between the real surface of a corroded steel component and the fatigue life was established. Steel structures often include numerous welded connections, which behave differently to corrosion exposure, due to existing stress concentrations from the welding geometry and residual stresses from the welding process. Hence, additional fatigue tests were conducted on corroded fillet and butt-welded specimens. In addition, 3D scans and residual stress measurements were performed. Subsequently, the fatigue tests were evaluated using local fatigue approaches, taking the real weld geometry from the 3D scans and the measured residual stresses into account. It was shown that stress concentrations had a significant impact on the fatigue life prediction. Additionally, it was demonstrated that residual stresses played a crucial role and must be considered for assessing the remaining fatigue life of corroded steel components. The application of local methods minimized the scatter in the SN-curves and thus increased the reliability. It was shown, that the consideration of the actual condition of corroded components in the calculation of fatigue strength is possible, also for welded samples. Finally, the replica technique was introduced. With the replica technique, imprints of corroded components can be created during inspections of the structures. These imprints are then scanned in the laboratory and analysed using the methods presented in this work to determine their stress concentrations, which are correlated with the endurable load cycles. The replica technique can be applied to both welded and non-welded components. This allows the transfer of the findings from executed fatigue tests and numerical calculations to real structures

An Intelligent Monitoring System of Vehicles on Highway Traffic

Vehicle speed monitoring and management of highways is the critical problem of the road in this modern age of growing technology and population. A poor management results in frequent traffic jam, traffic rules violation and fatal road accidents. Using traditional techniques of RADAR, LIDAR and LASAR to address this problem is time-consuming, expensive and tedious. This paper presents an efficient framework to produce a simple, cost efficient and intelligent system for vehicle speed monitoring. The proposed method uses an HD (High Definition) camera mounted on the road side either on a pole or on a traffic signal for recording video frames. On the basis of these frames, a vehicle can be tracked by using radius growing method, and its speed can be calculated by calculating vehicle mask and its displacement in consecutive frames. The method uses pattern recognition, digital image processing and mathematical techniques for vehicle detection, tracking and speed calculation. The validity of the proposed model is proved by testing it on different highways.Comment: 5 page

The impact of e-service quality on atitude toward online shopping

The research was designed to fill the gap in the existing body of knowledge regarding attitudes toward online shopping and differences in electronic service quality perception between two different geographical and cultural countries. In addition, this research extended previous effort done in an online shopping context by providing evidence that high service quality increase consumers’ trust perception, which in turn results in favorable attitude toward online shopping, with risk perception moderating the impact on consumer’s trust. Cluster random sampling was used to select respondents with previous online shopping experience. Correlation and hierarchical regression was used to analyze the direct and indirect relationship between service quality, risk, trust and attitude, while t-test was used to compare the two cultures in e-service quality perception. The present study demonstrates that e-service quality is affected by consumer’s culture. This research also provides evidence that trust in Internet shopping is built on high service quality. Notably, risk moderates the effect of e-service quality on trust toward online retailer. Finally, the research highlights the significant effect of trust on the attitude towards online shopping