Journal of Engineering and Technological Sciences
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Unload Pull-out Test of Full-length Grouted Bolts in Slope Reconstruction and Expansion
Get PDFThe Unloading Pull-out Test Method (UPTM) is proposed to evaluate the residual stress of existing anchorage systems and explore the actual stable state of the slope before excavation. A series of destructive pull-out tests are applied to detect the working state of the existing rock bolts. The working load and ultimate load of the existing bolts are determined by field test measurement of the P-S curve. The experimental result showed that a displacement increment of the bolts was present in the elastic stage, the elastoplastic stage, the slip stage, and the debonding stage. The working load and the ultimate load were in the elastoplastic stage and the debonding stage respectively. The working load of the bolts is closely related to the sliding deformation. The ultimate load of the bolts, however, is only related to the design parameters, slope lithology and other factors. After 20 years of natural forces acting on the bolts in the slope, their ultimate bearing capacity had a stress loss of 24.0% ~ 32.0%
Site Soil Classification Interpretation Based on Standard Penetration Test and Shear Wave Velocity Data
Get PDFSite soil classification provides vital information for predicting the soil amplification or the site factor. The site factor is important for calculating the surface spectral acceleration in the seismic design of buildings. Based on the Indonesian seismic code, site soil classification can be conducted by calculating the average standard penetration (N-SPT) resistance, the average shear wave velocity (VS) and the average undrained soil strength (Su) of the upper 30 m of a subsoil layer. Different results may be obtained at the same location when the site soil classification is predicted using N-SPT than when using VS data. The restriction of N-SPT values until a maximum of 60 compared to a VS maximum of 750 m/sec can produce different soil classes and will directly impact the calculation of the surface spectral acceleration. This paper describes the different results of site soil classification prediction calculated using the average N-SPT and the average VS, conducted at Semarang City, Indonesia. Site soil classification maps developed based on both datasets are also presented, to evaluate the different site soil classification distributions. Only soil classes SD and SE were observed using N-SPT maximum 60, whereas soil classes SC, SD and SE were observed using N-SPT maximum 120
Development of Ultralow Interfacial Tension Lignosulfonate from Kraft Black Liquor for Enhanced Oil Recovery
Get PDFIndonesia aims to implement large-scale enhanced oil recovery (EOR) to increase the national oil production. Chemical EOR is a promising technology to boost the production of old reservoirs with the aid of surfactants and polymers. Thus, the production of low-cost EOR surfactants from local resources with acceptable performance is highly attractive. The objective of the present work was to demonstrate the development of low-cost lignosulfonate surfactant production from kraft black liquor (BL). First, lignin was isolated from black liquor using a novel CO2 bubbling technique, followed by addition of coagulants. Next, sodium lignosulfonate (SLS) was synthesized from the resulting lignin, followed by formulation of SLS with octanol and palm fatty acid distillate (PFAD) soap to obtain an ultralow interfacial tension (IFT) surfactant. The initial IFT value of the SLS solution was already high at 0.7 mN/m. After formulation, the composition SLS:PFAD soap:octanol = 70:22:8 (wt%) improved the IFT value to 3.1 10-3 mN/m. An ultralow IFT in the range of 10-3 mN/m as achieved here fulfills the required IFT value for EOR surfactant
Characteristics of Polymeric Fiber Reinforced Cementitious Composite (PFRCC) under Uniaxial Compression
Get PDFThis study aimed to evaluate the compressive characteristics and toughness of polymeric fiber reinforced cementitious composites (PFRCC). In the experimental program, polyvinyl alcohol (PVA) fibers were used to prepare two groups of PFRCC cylinders with different fiber contents. The main factor considered in this study was the reinforcing index. Several parameters were investigated, i.e. compressive strength, elastic modulus, strain at peak stress, Poisson’s ratio and toughness of PFRCC. The results revealed that there was a reduction in both compressive strength and elastic modulus as the reinforcing index increased, while a significant increase in the strain at peak stress was observed. Moreover, a comparison was made between different methods of toughness estimation and it was found that 7.9 was the best reinforcing index for PVA fibers based on the energy absorption performance and ductility of PFRCC. Furthermore, an empirical model is proposed in this paper to predict the PFRCC-PVA compressive stress-strain curve. The proposed model features new formulas to calculate a number of important coefficients to plot the curve based on the reinforcing index value. Besides that, the model had good convergence compared to the experimental results, with perfect values for both variance and correlation coefficient
The Effect of Temperature on the Electrical Characteristics of Nanofluids Based on Palm Oil
Get PDFThis study sought to apply nanotechnology to develop the electrical characteristics of palm oil. Experiments were conducted using three types of nanoparticles: zinc oxide (ZnO), titanium dioxide (TiO2), and barium titanate (BaTiO3). The nanofluid samples were prepared by mixing the nanoparticles with palm oil using various processes. In the first scenario, a combination of palm oil with nanoparticles at 0.01 vol% was created, while the next sample had 0.03 vol% of nanoparticles. The samples were then fully dispersed using a magnetic stirrer, followed by ultrasonic dispersal in order to ensure homogeneity of the nanofluid. The electrodes were set 2.5 mm apart and the test was performed six times on each test sample in compliance with the IEC 60156 standard. The voltage breakdown characteristics were recorded for each of the liquids at temperatures varying from 35 °C to 90 °C. The results showed that for the palm oil samples containing nanoparticles, the voltage breakdown was greater than for the samples containing unmodified palm oil
Seismic Behavior of Concrete-Filled Steel Tube (CFST) Column and Reinforced Concrete (RC) Beam Connections under Reversed Cyclic Loading
Get PDFPrevious studies on the connection between concrete-filled steel tube (CFST) columns and reinforced concrete (RC) beams have shown a loss of joint confinement because the steel tube was completely or partially cut in the joint area. This research presents a new connection system that provides joint confinement through a continuous steel tube. Potential sliding shear at the smooth interface between the columns and beams in the joint face is mitigated using two mechanisms: (i) shear connectors and (ii) longitudinal web beam reinforcement. This study tested two CFST column and RC beam joints to 4.5% drift ratio under combined compression axial load and lateral cyclic load. The experimental results revealed no cracks at the joint zone and the specimens satisfied the ACI 374.1-05 criteria, despite minor sliding at the beam-column interface. The finite element (FE) model showed good agreement with the experimental results
Membrane Oxygenator for Extracorporeal Blood Oxygenation
Get PDFExtracorporeal blood oxygenation has become an alternative to supply O2 and remove CO2 from the bloodstream, especially when mechanical ventilation provides insufficient oxygenation. The use of a membrane oxygenator offers the advantage of lower airway pressure than a mechanical ventilator to deliver oxygen to the patient’s blood. However, research and development are still needed to find appropriate membrane materials, module configuration, and to optimize hydrodynamic conditions for achieving high efficient gas transfer and excellent biocompatibility of the membrane oxygenator. This review aims to provide a comprehensive description of the basic principle of the membrane oxygenator and its development. It also discusses the role and challenges in the use of membrane oxygenators for extracorporeal oxygenation on respiratory and cardiac failure patients
Improved Modified Symbiosis Organisms Search (IMSOS): A New and Adaptive Approach for Determining Model Parameters from Geoelectrical Data
Get PDFSymbiotic Organisms Search (SOS) is a global optimization algorithm inspired by the natural synergy between the organisms in an ecosystem. The interactive behavior among organisms in nature simulated in SOS consists of mutualism, commensalism, and parasitism strategies to find the global optimum solution in the search space. The SOS algorithm does not require a tuning parameter, which is usually used to balance explorative and exploitative search by providing posterior sampling of the model parameters. This paper proposes an improvement of the Modified SOS (MSOS) algorithm, called IMSOS, to enhance exploitation along with exploration strategies via a modified parasitism vector. This improves the search efficiency in finding the global minimum of two multimodal testing functions. Furthermore, the algorithm is proposed for solving inversion problems in geophysics. The performance of IMSOS was tested on the inversion of synthetic and field data sets from self-potential (SP) and vertical electrical sounding (VES) measurements. The IMSOS results were comparable to those of other global optimization algorithms, including the Particle Swarm Optimization, the Differential Evolution and the Black Holes Algorithms. IMSOS accurately determined the model parameters and their uncertainties. It can be adapted and can potentially be used to solve the inversion of other geophysical data as well
Tensile Characteristics of Bio-Composite Material Reinforced with Corn Skin
Get PDFThe main focus of the present work was to study corn skin as reinforcement of polyester bio-composite (CSPCs). The effect of reinforcement type, i.e. short fibers and discontinuous chips, on the tensile properties was studied. The corn skin materials were chemically treated with NaOH and added as reinforcement of polyester bio-composite using the hand lay-up fabrication method. Tensile tests were carried out according to ASTM D3039. The tensile strength characteristics of stress and modulus showed a different behavior between the two types of reinforcement due to a slight difference in specimen thickness, which affected the calculated stress and modulus values. Furthermore, from a physical properties point of view, the larger surface area of CSC compared to CSF, which still contains a lignin layer after the treatment with NaOH, could decrease the interfacial bonding between polyester as the matrix and CSC as the reinforcement. The tensile damage characteristics showed brittle behavior, propagataing perpendicular to the loading direction. Matrix cracking and interfacial debonding were identified as the main two damage modes of the CSF bio-composite and the CSC bio-composite, where the final failure was dominated by fiber pull out and chip fracture
