Experimental Evaluation of Helical Piles for Underpinning Shallow Foundations on Soils Susceptible to Liquefaction using Shake Table Tests

The severe damages observed during past earthquakes resulting from the liquefaction of shallow saturated soil deposits underneath structures have demonstrated the necessity for further research in the area of liquefaction-induced ground movement effects. This research explores the utilization of helical piles to reduce liquefaction-induced foundation settlement and investigates their seismic performance in liquefiable grounds. Twenty-two shake table tests were conducted to examine the dynamic behavior of helical piles and their efficiency in liquefiable grounds. Among these tests, two shake table test series, one without any mitigation measures and one using helical piles, were conducted using the shake table facility at the University of California, San Diego (UCSD). The remaining shake table tests were conducted using the scaled shake table facility at the University of Nevada, Reno (UNR). During large-scale test series at UCSD, the soil and structural components were extensively instrumented and subjected to two consistently applied shaking sequences. The model ground included a shallow liquefiable layer aimed at replicating the subsurface ground conditions observed in past earthquakes in New Zealand, Japan, and Turkey. Results from the first test series of large-scale tests (i.e., without mitigation) indicated that the flow velocity due to the hydraulic transient gradient displayed an upward flow in the loose layer, which explains the observed sand ejecta. This series of shake table tests aimed at reproducing the potential damage during liquefaction of shallow liquefiable deposits. As a result, the average foundation settlement in Shake 1 and Shake 2 were measured to be 28 cm and 42.7 cm, respectively. Measured foundation settlements were compared to the estimated foundation settlement obtained from Liu and Dobry [1997] and Bray and Macedo’s [2017] simplified procedures. The observed foundation settlement generally was higher than the estimated settlement. In the second large-scale test series, reduced excess pore-water pressure generation around the group of helical piles is mainly attributed to the increased relative density around their zone of influence as a result of installation. The foundation supported on helical piles underwent almost no differential settlement and tilt. Moreover, a significant reduction took place during the Helical Pile test compared to the Baseline test (i.e., 96% reduction on average). Liquefaction-induced settlement mechanisms are categorized as 1- shear-induced, 2- volumetric-induced, and 3- ejecta-induced. The post-shaking liquefaction-induced settlement mechanisms (i.e., volumetric and ejecta-induced mechanisms) did not affect the foundation settlement supported by helical piles. This series of large-scale shake table tests delivered a unique benchmark for calibration of numerical models, and simplified procedures to reliably estimate liquefaction-induced building settlements. Although this study introduced helical piles as a reliable and highly efficient measure to mitigate liquefaction-induced foundation tilt and settlement, the proper design and application of helical piles in seismic areas still need thorough investigation due to possible amplified superstructure response. In the scaled shake table test series at UNR, multiple shakings were applied during each test series to evaluate the seismic behavior of the scaled helical piles and the slender shaft, taking into account various response parameters. These scaled shake table tests provided the opportunity to perform parametric studies on the effects of ground motion amplitude, liquefiable layer densification, superstructure weight, and the number of helices on the helical piles. Considerable ground settlements were measured during the first shaking in each test series, however negligible helical pile and slender shaft settlements were observed during all tests. The bending moment variation showed a similar trend along the depth for the helical piles and the slender shaft: the maximum moment was consistently observed at the boundary between dense and liquefiable layers. The observed bending moments along the depth increased with increases in input motion amplitude and superstructure weight. Densification of the liquefiable layer during different test series reduced the maximum bending moment along the depth for each pile due to increased relative density. Increasing the number of helices improved the dynamic performance of the helical piles compared to the slender shaft such as maximum bending moment, maximum horizontal displacement, residual horizontal displacement, and superstructure acceleration in different ground conditions

Battery Hardware Simulator

This project aims to develop a battery hardware simulator, which will serve as a tool for studying microgrids. The primary objective is to create a simulation system that can emulate various battery technologies that are used in microgrids, including lithium-ion and lead acid. By utilizing this battery simulator, Cal Poly students can safely test battery management systems and battery-sensitive electronics without the inherent risks associated with real batteries. Our project implemented this design with a 4-quadrant programmable power supply (ITECH) connected to an AP Systems grid tied inverter. The power supply acts as the battery which can receive or supply power from or to the grid through the inverter. The power supply is programmed with different battery technology discharge profiles using the ‘List’ function

The Effect Of Explicit Instruction On Formulaic Sequences And Working Memory On Intermediate Malaysian Esl Learners᾽ Oral Fluency

Most Malaysian university graduates still experience difficulties in their work place because of their poor English language, mainly in speaking skill. Many researchers have claimed that the use of formulaic sequences facilitates the students̕ oral production and increases their L2 oral fluency, especially the low proficient L2 learners when they are not able to create new sentences or retrieve the appropriate vocabularies. In this study, efforts were made to investigate the effect of the explicit instruction of formulaic sequences on Malaysian L2 learners᾽oral fluency while considering the role of their working memory capacity, as one of the important effective factors in learning language, on their use of formulaic sequences and their L2 oral fluency. Therefore, a sample of 54 students in their second semester of academic session 2015-2016, enrolled in a preparatory English language course, were selected through purposive sampling. They were assigned to two groups including the treatment group (28 participants) and the non-treated group (26 participants). Both samples were pre-tested for the homogeneity in their performance on the temporal variables of L2 oral fluency and their use of formulaic sequences through a spontaneous narrative monologue test which was followed by a specific treatment incorporated in the normal contents of the preparatory English language course for the treatment group and lasted for fifteen three-hour sessions. However, the control group received only the normal contents of the preparatory English language course

Similarity Search and Analysis Techniques for Uncertain Time Series Data

Emerging applications, such as wireless sensor networks and location-based services, require the ability to analyze large quantities of uncertain time series, where the exact value at each timestamp is unavailable or unknown. Traditional similarity search techniques used for standard time series are not always effective for uncertain time series data analysis. This motivates our work in this dissertation. We investigate new, efficient solution techniques for similarity search and analysis of both uncertain time series models, i.e., PDF-based uncertain time series (having probability density function) and multiset-based uncertain time series (having multiset of observed values) in general, as well as correlation queries in particular. In our research, we first formalize the notion of normalization. This notion is used to introduce the idea of correlation for uncertain time series data. We model uncertain correlation as a random variable that is a basis to develop techniques for similarity search and analysis of uncertain time series. We consider a class of probabilistic, threshold-based correlation queries over such data. Moreover, we propose a few query optimization and query quality improvement techniques. Finally, we demonstrate experimentally how the proposed techniques can improve similarity search in uncertain time series. We believe that our results provide a theoretical baseline for uncertain time series management and analysis tools that will be required to support many existing and emerging applications

Friction-induced Vibration in Lead Screw Systems

Lead screw drives are used in various motion delivery systems ranging from manufacturing to high precision medical devices. Lead screws come in many different shapes and sizes; they may be big enough to move a 140 tons theatre stage or small enough to be used in a 10ml liquid dispensing micro-pump. Disproportionate to the popularity of lead screws and their wide range of applications, very little attention has been paid to their dynamical behavior. Only a few works can be found in the literature that touch on the subject of lead screw dynamics and the instabilities caused by friction. The current work aims to fill this gap by presenting a comprehensive study of lead screw dynamics focusing on the friction-induced instability in such systems. In this thesis, a number of mathematical models are developed for lead screw drive systems. Starting from the basic kinematic model of lead screw and nut, dynamic models are developed with varying number of degrees of freedom to reflect different components of a real lead screw drive from the rotary driver (motor) to the translating payload. In these models, velocity-dependent friction between meshing lead screw and nut threads constitute the main source nonlinearity. A practical case study is presented where friction-induced vibration in a lead screw drive is the cause of excessive audible noise. Using a complete dynamical model of this drive, a two-stage system parameter identification and fine-tuning method is developed to estimate parameters of the velocity-dependent coefficient of friction. In this approach the coupling stiffness and damping in the lead screw supports are also estimated. The numerical simulation results using the identified parameters show the applicability of the developed method in reproducing the actual systems behavior when compared with the measurements. The verified mathematical model is then used to study the role of various system parameters on the stability of the system and the amplitude of vibrations. These studies lead to possible design modifications that solve the system’s excessive noise problem. Friction can cause instability in a dynamical system through different mechanisms. In this work, the three mechanisms relevant to the lead screw systems are considered. These mechanisms are: 1. negative damping; 2. kinematic constraint, and; 3. mode coupling. The negative damping instability, which is caused by the negative gradient of friction with respect to sliding velocity, is studied thorough linear eigenvalue analysis of a 1-DOF lead screw drive model. The first order averaging method is applied to this model to gain deeper insight into the role of velocity-dependent coefficient of friction and to analyze the stability of possible periodic solutions. This analysis also is extended to a 2-DOF model. It is also shown that higher order averaging methods can be used to predict the amplitude of vibrations with improved accuracy. Unlike the negative damping instability mechanism, kinematic constraint and mode coupling instability mechanisms can affect a system even when the coefficient of friction is constant. Parametric conditions for these instability mechanisms are found through linear eigenvalue analysis. It is shown that kinematic constraint and mode coupling instability mechanisms can only occur in self-locking lead screws. The experimental case study presented in this work demonstrates the need for active vibration control when eliminating vibration by design fails or when it is not feasible. Using the sliding mode control method, two speed regulators are developed for 1-DOF and 2-DOF lead screw drive system models where torque generated by the motor is the controlled input. In these robust controllers, no knowledge of the actual value of any of the system parameters is required and only the upper and lower bounds of parameters are assumed to be available. Simulation results show the applicability and performance of these controllers. The current work provides a detailed treatment of the dynamics of lead screw drives and the topic of friction-induced vibration in such systems. The reported findings regarding the three instability mechanisms and the friction parameters identification approach can improve the design process of lead screw drives. Furthermore, the developed robust vibration controllers can be used to extend the applicability of lead screws to cases where persistent vibrations caused by negative damping cannot be eliminated by design modifications due to constraints

Effect of Edible Coatings (Xanthan gum and Carob gum) on the Physicochemical and Sensory Properties of French Fries Potatoes

In the present study, French fries potatoes were coated with combination of xanthan gum and carob gum or each of them separately at different concentrations of 0.25, 0.5, 0.75 and 1.5%( w/v) beside the control sample which was considered without coating. Samples were fried at 180  for 6 min. The percentage of hydrocolloids coating, moisture content, oil uptake, textural characteristic (hardness index), frying efficiency, colorimetric characteristics (brightness, redness and yellowness indexes plus color difference) and sensory evaluation (Flavor, aroma, appearance, color and overall acceptance) of potato strips were measured.The results indicated that when the hydrocolloids coating of potato strips applied, the moisture retention capacity increased, oil uptake decreased, frying efficiency increased, brightness index reduced and redness/yellowness index increased. Also by increasing the hydrocolloid initial concentration over 1%, sensory evaluation of the samples decreased. Sensory and physiochemical properties significantly decreased in the control sample (p≥0.05). As a final point, the sample contained 0.25% carob gum and 0.75% xanthan gum was introduced as superior treatment

Emerging functions for snornas and snorna‐derived fragments

The widespread implementation of mass sequencing has revealed a diverse landscape of small RNAs derived from larger precursors. Whilst many of these are likely to be byproducts of degradation, there are nevertheless metabolically stable fragments derived from tRNAs, rRNAs, snoRNAs, and other non-coding RNA, with a number of examples of the production of such fragments being conserved across species. Coupled with specific interactions to RNA-binding proteins and a growing number of experimentally reported examples suggesting function, a case is emerging whereby the biological significance of small non-coding RNAs extends far beyond miRNAs and piRNAs. Related to this, a similarly complex picture is emerging of non-canonical roles for the non-coding precursors, such as for snoRNAs that are also implicated in such areas as the silencing of gene expression and the regulation of alternative splicing. This is in addition to a body of literature describing snoRNAs as an additional source of miRNA-like regulators. This review seeks to highlight emerging roles for such non-coding RNA, focusing specifically on “new” roles for snoRNAs and the small fragments derived from them.Maliha Wajahat, Cameron Peter Bracken and Ayla Oran

Role of serum Immunoglobulin E level in diagnosis of severity of cough variant asthma

Introduction: Cough variant asthma (CVA) is known by airway Hyper responsiveness and nonproductive chronic cough without wheezing for a minimum duration of 8 weeks. It is less common form of asthma. This study was conducted aiming to diagnose the role of serum Immunoglobulin E (IgE) in diagnosis of cough variant form of the disease. Methods: In this cross sectional study, 80 patients with an age range of 5-14 years were included with clinical criteria for CVA who referred to pulmonology clinic of Tabriz Children Hospital, Tabriz, Iran. Serum IgE level was measured and severity of CVA based on Global Initiative for Asthma (GINA) classification was determined, finally the relationship between serum IgE level and severity of CVA was evaluated. Results: In patients with CVA without history of allergic disease, mean serum titer of IgE was 138.2 ± 17.5. Significant difference of serum IgE level in different severities of CVA was detected (P = 0.001). Conclusion: Serum IgE level in patients with CVA is a reliable marker for diagnosis and evaluation of the severity of disease

Crystal structure of 2,2′-(propane- 1,3-dilylbis(azaneylylidene))bis(methanylylidene) bis(4-methylphenol), C19H22N2O2

C19H22N2O2, monoclinic, P21/c (no. 14), a = 19.3063(4) Å, b = 5.83200(10) Å, c = 14.7996(3) Å, β = 92.715(1)°, V = 1664.48(6) Å3, Z= 4, Rgt(F) = 0.0423, wRref (F2) = 0.1102, T = 100(2) K