Simplified homogenization method in stone column designs

AbstractThe homogenization technique has been developed to model stone column improved grounds by establishing the equivalent material properties for the composite ground. However, homogenization techniques based on the elasto-plastic behavior of the constituent materials found in literature require modification in terms of the finite element constitutive models which are difficult for practical engineers to apply. Therefore, a simple yet effective way of predicting the consolidation performance of stone column improved grounds has been invoked in this study. The method is called the equivalent column method (ECM). The new method provides not only equivalent stiffness for the composite material, but also equivalent permeability. The method is derived from an analysis using the unit cell model in a 2D finite element axisymmetrical model. The settlement is calculated and a correction factor is obtained via a comparison with the results calculated using a single averaging composite stiffness for the improved ground. Correlations are summarized in the form of design charts for the key parameters, such as the area replacement ratio, the loading intensity, and the friction angle of the column material. Through a series of tests for different area replacement ratios, the equivalent permeability is established and presented in a design chart for different permeability ratios. ECM shows a good agreement with the current design methods and field results. The advantage of the proposed method over other homogenization techniques is the simplicity of its use which renders easy model set-up in the finite element program, especially for embankments and large tank problems, besides its extra ability to predict the consolidation time

Class D amplifier power stage with PWM feedback loop

This paper presents a Second-Order Pulse Width Modulation (PWM) feedback loop to improve Power Supply Rejection (PSR) of any open-loop PWM Class-D amplifiers (CDAs). PSR of the audio amplifier has always been a key parameter in mobile phone applications. In contrast to Class AB amplifiers, the poor PSR performance has always been the major drawback for CDAs with half-bridge connected power stage. The proposed PWM feedback loop is fabricated using GLOBALFOUNDRIES' (GF’s) 0.18 µm CMOS process technology. The measured PSR is more than 80 dB and the measured Total Harmonic Distortion (THD) is less than 0.04% with a 1 kHz input sinusoidal test tone

High Performance Substrate Integrated Waveguide Bandstop Filter using Dual-radial Cavity Resonator

A SIW bandstop filter is designed by coupling two cavity resonators to the SIW line. Dual-radial cavity resonators are proposed to design the SIW bandstop filter. Two single radial cavity resonator SIW bandstop filter are designed first. After that, a dual-radial cavity resonator SIW bandstop filter is designed based on the two single radial cavity resonator SIW bandstop filter. The designed bandstop filter operates at X-band frequency with a stopband from 8.7GHz to 9.2GHz, and it is implemented on RO4350B substrate with a thickness of 0.508mm. An insertion loss of less than 3dB is achieved, and the bandstop filter have a sharp roll of with attenuation of -34dB. This bandstop filter can be applied in the radar syste

A low number of introduced marine species in the tropics: A case study from Singapore

Non-indigenous marine species (NIMS) are being transported around the world by anthropogenic mechanisms, particularly by vessels in ballast water or as biofouling. A small subset of NIMS become invasive marine species (IMS) and can cause considerable damage to local marine ecosystems. Understanding where NIMS originate, how they are transported, and their effects in the new environments are crucial to the management of IMS. As one of the busiest ports in the world that handles tens of thousands of high invasion-risk vessels annually, Singapore is regarded as being at very high risk for the introduction of NIMS and IMS. However, a compilation of 3,650 marine invertebrates, fishes and plants revealed that only 22 species have been confirmed as NIMS. The results are consistent with a growing dataset that suggests biodiverse marine ecosystems in the tropical Indo-West Pacific are less susceptible to introductions than previously thought

Models of electron transport in single layer graphene

The main features of the conductivity of doped single layer graphene are analyzed, and models for different scattering mechanisms are presented.Comment: 15 pages. Submitted to the Proceedings of the ULTI symposium on Quantum Phenomena and Devices at Low Temperatures, Espoo, Finland, to be published in the Journ. of Low. Temp. Phy

Feasibility Study of a Facility to Produce Injection Molded Parts for Automotive Industry

[EN] This study aims at the preliminary assessment in designing a complete stand-alone industrial facility to produce injection molded parts for the automotive industry. A draft design solution to allow the company to evaluate the capital investment was performed giving an estimated solution in project profitability. Proposed successive design steps were developed. It includes the definition of input data and information, quantity determination, plat layout diagrams, machine selection, selection of material handling equipment, plant layout design including space requirements of production centers, aísles, support functions. Moreover, the outdoor facility masterplan design is also proposed. Finally, investment calculation via cash flow analysis is calculated.Yudianto, A.; Tan, H.; Qu, Z.; Xue, Q.; Naveen, A.; Mushtaq, M.; Gopi, K. (2020). Feasibility Study of a Facility to Produce Injection Molded Parts for Automotive Industry. International Journal of Production Management and Engineering. 8(1):45-57. https://doi.org/10.4995/ijpme.2020.12360455781Al-Aomar, R. (2006). Capacity-constrained production scheduling of multiple vehicle programs in automotive pilot plant. International Journal of Production Research, 44(13), 2573-2604. https://doi.org/10.1080/00207540500521212Cagliano, A. C., Chiabert, P. (2018). Plant and manufacturing system lecture notes. Politecnico di Torino, Italy.Chingua, S. Nyemba, W. R., Boora, K., Mbohwa, C. (2019). Feasibility study of the materials handling and development of a sustainable conveying system in plastics recycling and manufacture. Procedia Manufacturing, 33, 383-390. https://doi.org/10.1016/j.promfg.2019.04.047Derhami, S., Smith, J. S., Gue, K. R. (2019). Space-efficient layouts for block stacking warehouse. IISE Transaction, 51(9), 957-971. https://doi.org/10.1080/24725854.2018.1539280Eksangsri, T., Jaiwang, T. (2014). Feasibility study on reuse of washed water in electronic industry: case study for flexible printed circuit board manufacturing in Thailand. Procedia Environmental Sciences, 20, 206-214. https://doi.org/10.1016/j.proenv.2014.03.027Fu, M., Kaku, B. K. (1997). Minimizing work-in-process and material handling in the facilities layout problem. IIE Transactions, 29, 29-36. https://doi.org/10.1080/07408179708966309Halil, F. M., Nasir, N. M., Hassan, A. A., Shukur, A. S. (2016). Feasibility study and economic assessment in green building projects. Procedia-Social and Behavioral Sciences, 222, 56-64. https://doi.org/10.1016/j.sbspro.2016.05.176Hazaras, M. J., Swartz, C. L. E., Marlin, T. E. (2013). Industrial application of a continuous-time scheduling framework for process analysis and improvement. I&EC research Industrial & Engineering Chemistry Research, 53, 259-273. https://doi.org/10.1021/ie4006904Hwang, D. K., Cho, K., Moon, J. (2019). Feasibility study on energy audit and data driven analysis procedure for building energy efficiency: bench-marking in Korean hospital buildings. Journal Energy 12(15), 3006. https://doi.org/10.3390/en12153006Jung, S., Ng, D., Ovalle, C. D., Roman, R, V., Mannan, M. S. (2011). New approach to optimizing the facility sitting and layout for fire and explosion scenarios. I&EC research Industrial & Engineering Chemistry Research, 50, 3928-3937. https://doi.org/10.1021/ie101367gKingenberg, W., Boksma, J. D. (2010). A conceptual framework for outsourcing of material handling activities in automotive: differentiation and implementation. International Journal of Production Research, 48(16), 4877-4899. https://doi.org/10.1080/00207540903067177Kovàcs, G. (2019). Layout design for efficiency improvement and cost reduction. Bull. Pol. Ac.: Tech., 67(3), 547-555. https://doi.org/10.24425%2Fbpasts.2019.129653Ma, T., Yang, H., Lu. L., Qi, R. (2017). Feasibility study of developing a zero-carbon-emission green deck in Hong Kong. Energy Procedia 105, 1155-1159. https://doi.org/10.1016/j.egypro.2017.03.487Morgan, B., Hejdenberg, J., Krapels, S. H., Amstrong, D. (2018). DO feasibility studies contribute to, or avoid, waste in research? PLos ONE 13(4), e0195951. https://doi.org/10.1371/journal.pone.0195951Pòvoa, A. P. B., (2002). Optimal design and layout of industrial facilities: a simultaneous approach. Ind. Eng. Chem. Res, 41, 3601-3609. https://doi.org/10.1021/ie010660sSchaller, J. (2008). Incorporating cellular manufacturing into supply chain design. International Journal of Production Research, 46(17), 4925-4945. https://doi.org/10.1080/00207540701348761Stephens, M. P., Meyers, F. E., (2013). Manufacturing facilities design and material handling - fifth edition. Purdue University Press, West Lafayette, Indiana.Sun, L., Luan, F., Pian, J. (2015). An effective approach for scheduling of refining process with uncertain iterations in steel-making and continuous casting process. IFAC-PapersOnLine, 48(3), 1966-1972. https://doi.org/10.1016/j.ifacol.2015.06.376Yang, Z., Djurdjanovic, D., Ni, J. (2007). Maintenance scheduling for a manufacturing system of machines with adjustable throughput. IIE Transactions, 39, 1111-1125. https://doi.org/10.1080/0740817070131533

High speed synchrotron X-ray imaging studies of the ultrasound shockwave and enhanced flow during metal solidification processes

The highly dynamic behaviour of ultrasonic bubble implosion in liquid metal, the multiphase liquid metal flow containing bubbles and particles, and the interaction between ultrasonic waves and semisolid phases during solidification of metal were studied in situ using the complementary ultrafast and high speed synchrotron X-ray imaging facilities housed respectively at the Advanced Photon Source, Argonne National Laboratory, US, and Diamond Light Source, UK. Real-time ultrafast X-ray imaging of 135,780 frames per second (fps) revealed that ultrasonic bubble implosion in a liquid Bi-8 wt. %Zn alloy can occur in a single wave period (30 kHz), and the effective region affected by the shockwave at implosion was 3.5 times the original bubble diameter. Furthermore, ultrasound bubbles in liquid metal move faster than the primary particles, and the velocity of bubbles is 70 ~ 100% higher than that of the primary particles present in the same locations close to the sonotrode. Ultrasound waves can very effectively create a strong swirling flow in a semisolid melt in less than one second. The energetic flow can detach solid particles from the liquid-solid interface and redistribute them back into the bulk liquid very effectively

Neutrophils infected with highly virulent influenza H3N2 virus exhibit augmented early cell death and rapid induction of type I interferon signaling pathways

AbstractWe developed a model of influenza virus infection of neutrophils by inducing differentiation of the MPRO promyelocytic cell line. After 5days of differentiation, about 20–30% of mature neutrophils could be detected. Only a fraction of neutrophils were infected by highly virulent influenza (HVI) virus, but were unable to support active viral replication compared with MDCK cells. HVI infection of neutrophils augmented early and late apoptosis as indicated by annexin V and TUNEL assays. Comparison between the global transcriptomic responses of neutrophils to HVI and low virulent influenza (LVI) revealed that the IFN regulatory factor and IFN signaling pathways were the most significantly overrepresented pathways, with activation of related genes in HVI as early as 3h. Relatively consistent results were obtained by real-time RT-PCR of selected genes associated with the type I IFN pathway. Early after HVI infection, comparatively enhanced expression of apoptosis-related genes was also elicited

Role of ABCB1 C3435T variant in response to antiepileptic drugs in epilepsy: a review

Over-expression of P-glycoprotein (P-gp), the encoded product of the ATP-binding cassette (ABC), sub-family B, member 1 (ABCB1/MDR1) gene, plays an important role in mediating multidrug resistance to antiepileptic drugs (AEDs) in about 30 of patients with epilepsy. Genetic variation may in part explain inter-individual differences in phenotype-genotype relationships in the pharmacological response of epilepsy patients to AEDs. The synonymous C3435T polymorphism is one of the most common allelic variants in the ABCB1/MDR1 gene, proposed in the causation of refractory epilepsy. Many studies have shown the relationship between C3435T polymorphism and refractoriness to AEDs in epilepsy. However, there is controversy between the findings of various studies, that is, whether ABCB1/MDR1 C3435T gene polymorphism is associated with response to AEDs in epilepsy patients. This review provides a background and discusses the results of investigations on possible confounding factors affecting the interpretation and implementation of association studies in this area

Can acclimation of thermal tolerance, in adults and across generations, act as a buffer against climate change in tropical marine ectotherms?

Thermal acclimation capacity was investigated in adults of three tropical marine invertebrates, the subtidal barnacle Striatobalanus amaryllis, the intertidal gastropod Volegalea cochlidium and the intertidal barnacle Amphibalanus amphitrite. To test the relative importance of transgenerational acclimation, the developmental acclimation capacity of A. amphitrite was investigated in F1 and F2 generations reared at a subset of the same incubation temperatures. The increase in CTmax (measured through loss of key behavioural metrics) of F0 adults across the incubation temperature range 25.4–33.4 °C was low: 0.00 °C (V. cochlidium), 0.05 °C (S. amaryllis) and 0.06 °C (A. amphitrite) per 1 °C increase in incubation temperature (the acclimation response ratio; ARR). Although the effect of generation was not significant, across the incubation temperature range of 29.4–33.4 °C, the increase in CTmax in the F1 (0.30 °C) and F2 (0.15 °C) generations of A. amphitrite was greater than in the F0 (0.10 °C). These correspond to ARR's of 0.03 °C (F0), 0.08 °C (F1) and 0.04 °C (F2), respectively. The variability in CTmax between individuals in each treatment was maintained across generations, despite the high mortality of progeny. Further research is required to investigate the potential for transgenerational acclimation to provide an extra buffer for tropical marine species facing climate warming