Thermal stability and performance trends of sustainable lignocellulosic olive / low density polyethylene biocomposites for better environmental green materials

The current trend in deteriorating mechanical performance of green polymeric-based materials has made it essential for designers to establish more reliable and sustainable bio-products. Here, the mechanical performance of Jordanian lignocellulosic olive fibers in polymeric-based composites has been methodically investigated. The outcomes of different reinforcement conditions on the desired mechanical performance of the olive leaf’s lignocellulosic fibers with low-density polyethylene (LDPE) composites have been examined, including the properties of tensile strength, tensile modulus, mechanical strain, impact strength, and the intensity per composite volume. This has been accomplished to determine the optimum reinforcement condition for the desired mechanical behavior as well as to establish the performance deterioration and enhancement trends of such bio-materials in a more consistent manner. The results signify that lignocellulosic olive fibers have exhibited various enhancements in terms of mechanical performance. Both the tensile strength and modulus of elasticity have been dramatically improved at 20 wt.% fiber content. This was the most desired reinforcement condition among all considered cases. The olive fibers also possess the capability of maintaining relatively high ductility and impact strength properties, making them suitable for various industrial applications where high ductility is necessary. Thermal stability analysis using TGA and DTG has been employed to obtain accurate results.

Decreased Key Pecking in Response to Reward Uncertainty and Surprising Delay Extension in Pigeons

The Pavlovian autoshaping paradigm has often been used to assess the behavioral effects of reward omission on behavior. We trained pigeons to receive a food reward (unconditioned stimulus or UCS) following illumination of a response key (conditioned stimulus or CS). In Experiment 1, one group of pigeons was trained with two 100% predictive CS-UCS associations (reward certainty) and another group with two 25% predictive CS-UCS associations (reward uncertainty) for 12 sessions. In both groups, the two CS durations were 8 s. Then, in each group, the duration of one CS remained unchanged and that of the other CS was suddenly extended from 8 to 24 s for 6 sessions. In Experiment 2, some experienced individuals (from Experiment 1) and naïve individuals formed two groups trained with a 24-s CS throughout for 18 sessions. Our results show that pigeons (a) pecked less at the uncertain than the certain CS, (b) decreased and then increased CS-pecking after extending CS duration, especially in the certainty condition, (c) were unresponsive to the 24-s CS in the absence of previous experience, and (d) decreased their response rate close to the end of a trial irrespective of the reinforcement condition, CS duration, and amount of training. These results are discussed in relation to several theoretical frameworks.

Magnetic Data Pattern Features at Longitudinal Defect Sites in Rebars Scanned by a Passive Magnetic Inspection Technology

Reinforced concrete is a versatile modern construction material. Despite its advantages as a composite material, corrosion of the embedded reinforcing steel leads to infrastructure deterioration and loss of service. Non-Destructive Testing (NDT) methods are required to quantify the reinforcement condition, and to help manage human and financial risks arising from unexpected outright failure or service restrictions. Reinforcement condition can be assessed using a novel, time- and cost-efficient NDT method based on the self-magnetic behaviour of ferromagnetic materials. In this study, the magnetic properties of three similar rebars, each having three similar sized longitudinal defects, are recorded and assessed through experiments and a numerical simulation model. Strong correspondence is demonstrated between the magnetic properties from numerical simulation and from the experimental objects. For instance, applying the experimentally obtained defect detection threshold to the mathematically simulated results allows accurate defect detection in the simulations, showing that self-magnetic behavior is a powerful tool for condition assessment of ferromagnetic reinforcing materials.

Analisis Stabilitas Lereng dalam Penanganan Longsoran di Jalan Tol Cipularang Km. 91+200 dan Km. 92+600 Menggunakan Metode Elemen Hingga (FEM)

ABSTRAKLongsoran terjadi di Jalan Tol Cipularang Km. 91+200 dan Km. 92+600. Longsoran terjadi karena adanya pergerakan pada lapisan batu lempung (clay shale), sehingga perlu adanya penanganan longsoran secara tepat dan efektif. Penanganan yang dipilih, yaitu dengan pemasangan perkuatan lereng berupa boredpile dan dinding penahan tanah. Dimensi boredpile yang digunakan yaitu berdiameter 80 cm. Analisis dilakukan dengan menggunakan Program Plaxis 2D yang berbasis metode elemen hingga, dengan memodelkan 2 (dua) kondisi yaitu kondisi eksisting dan kondisi dengan perkuatan. Analisis pada kondisi eksisting dilakukan dengan cara back analysis, sehingga hasil analisis kondisi eksisting sesuai dengan kejadian di lapangan. Analisis dilakukan di 6 (enam) titik untuk Km. 91+200 dan 2 (dua) titik untuk Km. 92+600. Dari hasil analisis didapat bahwa dengan adanya perkuatan pada lereng yang terjadi kelongsoran, nilai faktor keamanan naik hingga 242.2% dari kondisi eksisting.Kata Kunci: Longsor, Tol Cipularang, Km. 91+200 dan 92+600, Boredpile, etode Elemen Hingga, faktor keamanan ABSTRACTThe landslide are occurred at Cipularang toll road Km. 91+200 and Km. 92+600. The landslide occur because of the movement of clay shale soil layer, it means should be handled witih appropriate and effective way. For this case, reinforcement slope using boredpile and gravity wall are choosen. Dimension of the boredpile is 80 cm. The analysis was calculated using Plaxis 2D with finite element method with two different type of calculating model : existing condition (without reinforcement) and with reinforcement condition. Analysis for existing model are done by back analysis method that will gave the real condition from the field. The analysis are done by calculated in 6 (six) point area of slope for Km. 91+200 and 2 (two) point area of slope for Km. 92+600. The safety factor (SF) of the slope will increase up to 214% after reinforcement.Keywords: Landslide, Cipularang Toll Road, Km. 91+200 and 92+600, Boredpile, Finite Element Method, Safety Factor

3D Numerical Analysis of Centrifuge Tests on Embankments on Soft and Stiff Ground

The behavior of reinforced and unreinforced embankment on soft and stiff grounds has been investigated using the centrifuge tests and verified using numerical simulations. Four different cases have been investigated in this study based on various types of foundation materials and reinforcement condition. Two-dimensional (2D) and three-dimensional (3D) finite element programs, Plaxis 2D and Plaxis 3D Foundation respectively used to simulate and analyze the prototypes behavior provided by centrifuge tests. Deformation behavior, settlements and effect of reinforcement have been studied in this study. Comparison of the results of the numerical analysis with the measurements obtained from the centrifuge tests shows good agreement in terms of settlement and the reduction of settlement due to geosynthetics reinforcement.

Effects of reinforcement delay and rule explicitness on work performance

This study examined the effects of reinforcement delay and rule explicitness on performance. A 2 (immediate vs. delayed reinforcement) x 2 (explicit vs. implicit rule) factorial design was used. Eighty college students were recruited as participants and were randomly assigned to the four experimental groups. They performed a simulated work task and the dependent variable was the number of the work task correctly completed. Results indicated that in the delayed reinforcement condition, performance for the group who was given an explicit rule was higher than that for the group who was given an implicit rule. In the immediate reinforcement condition, however, performance for both groups was comparable.

Numerical Analysis of Deformation Effect on Adjacent Piles Due to Excavation

Combined with the project of an open cut metro tunnel passing through a viaduct, three- dimensional finite element method is applied to study the lateral deformation law of viaduct pile foundations induced by adjacent excavation in the pile foundations reinforcement and un-reinforcement conditions. The results show that the lateral deformation of pile foundations increases with the increasing of excavation depth. The closer distance and the larger deformation, the influence of pile foundations on excavation will be more obvious. The pile foundations deformation is significantly reduced when taking protection measures such as adding new piles, expanding the pile cap and strengthening stratum. Compared with the maximum deformation of the un-reinforcement condition, the reinforcement condition is only 27% to 30%, and the reinforcement measure is remarkably effective. In addition, the length of the piles, the depth of foundation pit, as well as the relative positions of walls and piles have significant influences on piles deformation forms, and it should be taken into account in the design and construction of foundation pit.