The main purpose of the current research is to implement different Geophysical Techniques (GT) in measuring wave velocity at different soil properties. For this purpose, twenty 6-in-diameter specimens have been prepared with different soil properties for index tests. In addition, two identical 1/3-scale strip footing model tests are constructed and instrumented with geophones, accelerometers, and load cells. The objectives of these large tests are to establish correlations between large and small strain wave velocity on granular materials. These relationships are necessary to predict, from in-situ velocity measurement, the velocity at large deformations required for numerical modeling of various soil materials. Index test results indicate that the Pwave velocity decreases as the soil water content and degree of saturation increases up to certain thresholds, which itself increases with the compaction effort. In addition, the wave velocity becomes larger as the soil includes more fine contents. The clay content affects the soil wave velocity; however, this affect varies with the specimen water content. Results also show that the effect of Portland cement on the soil wave velocity is significant, especially after 3-days curing time. Results of the scaled footing tests indicate that the P-wave velocity increases as the footing applied stress increases, and the largest value was measured directly at the bottom of footing. Finally, a relation that relates stress ratio with velocity ratio for strip footing is proposed for practical implementation.
In this paper, a study is conducted to investigate the use of microwave tomography in the imaging of human proximal legs. In microwave tomography, the human leg is radiated with non-ionizing low-power electromagnetic signals; variations in the dielectric properties of the leg results in changes to the signals measured at receivers in the imaging system. The dielectric properties constitute of the relative permittivity along with the conductivity of the leg tissues. The study herein is carried numerically using a two-dimensional electromagnetic solver implemented using the finite-element method. The human proximal leg geometry is created and meshed using MATLAB and GMSH. The generated mesh is imported to the finite-element solver along with the values of electric properties of various tissues. The simulations show that variations in bone dielectric properties is highly correlated to the variations of the electric fields within the microwave tomography system.
Implantable bioelectrodes have the potential to advance neuroprosthetic therapy tremendously; however, current bioelectrodes have limitations ranging from mechanical mismatch to immunological responses. This paper discusses the preparation of novel, low-cost, flexible bioelectrodes, consisting of silicone polymer and titanium (IV) dioxide, and presents a study of the prepared electrodes' electrochemical and mechanical characteristics. The tested material exhibited ductile properties with samples approaching an elongation of 266?fore rupture, and an elastic modulus of 6.6296 MPa, along with a satisfactory bulk impedance of 93 K?, thus supporting its' capability to be synthesized into implantable electrode.
The microfluidic probe (MFP) is an open space microfluidic device that combines the concepts of hydrodynamic flow confinement (HFC) and scanning probes to overcome the closed channel restrictions of conventional microfluidic devices. In biology, this allows for analysis of mammalian cells, neurons and tissue samples that are otherwise difficult to culture in conventional microfluidic devices. In this paper, we demonstrate how 3-D printing can be used to expedite the design-test cycle of the MFP and hence democratize the concept. The 3D printing procedures were adapted in fabricating the MFPs that were used for all experiments. Characterization of MFP's flow profile footprints are performed by comparisons with numerically calculated profiles. Application of the MFP is then used to selectively label adherent cells cultured in a Petri dish, within their conventional culture environment. Results show that while the 3D printed probes contain some artifacts, they function just as well as MFPs microfabricated using conventional techniques. Overall, this fabrication demonstrates a rapid, easy, and affordable fabrication technique for the MFP.
In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs from a mixed age nematode population, which can subsequently be cultured to a desired developmental stage. For the sorting of a mixture containing three different developmental stages, eggs, L1 and L4, we utilized a microfluidic spiral chip with trapezoidal channel to obtain sorting efficiency (SE) above 97% and sample purity (SP) above 80% for eggs at different flow rates up to 10 mL/min. The result demonstrated a cost effective, simple, and highly efficient method of synchronizing C. elegans at high throughput (~4,200 organisms/min at 6 mL/min), while eliminating challenges of clogging and non-reusability of membrane-based filtration. Due to its simplicity, our method can be easily adopted in the C. elegans research community.
Early diagnosis of the cardiac abnormalities during the pregnancy may reduce the risk of perinatal morbidity and mortality. Cardiotocography (CTG) is a means of recording the fetal heartbeat from the Doppler ultrasound (DUS) and the uterine contractions during the pregnancy and this method is commonly used to screen for fetal abnormalities. DUS, which is commonly used for monitoring the fetal heart rate, can also be used for identifying the event timings of fetal cardiac valve motions. In this study, a new technique called Swarm decomposition is proposed to analyze the fetal cardiac Doppler ultrasound signals for the fetal cardiac timing events estimation. Decomposing the fetal Doppler signal using the swarm intelligence achieved an excellent extraction of the fetal cardiac timing events in the most cases in early and late gestational ages of the pregnancy. Therefore, this technique would be useful for reliable screening of fetal wellbeing.
Liquefied gases are in common use for a variety of purposes, for example, liquid Propane serves as a domestic fuel, liquid Oxygen is carried in cylinders, and is provided to hospitals for patients suffering from breathing problems. In this study , simulation of air liquefaction process and its separation was done successfully using Advanced System for Process Engineering (ASPEN) Plus simulating tool in order to increase the quality of products and to decrease the operational cost simultaneously. The model under consideration was Linde single-column system. Also, the effect of variation of various process conditions on yield, purity of final product, and temperature were analyzed. Results obtained showed that by using Linde single column system, oxygen of almost 99% purity could be obtained. However, the purity of nitrogen obtained was only about 90%. As such, Linde single-column system can be used when oxygen is the desirable product. In the study, cost analysis of the processes was not considered. So, as a future recommendation, cost analysis can be done, leading to optimization of the entire process.
Pure cobalt ferrite and mixed cobalt nickel ferrites were prepared by sol-gel auto-combustion method. The structure was mainly investigated by X-Ray Diffraction. The catalytic activities of the prepared samples were investigated by studying the photo- and non-photocatalytic degradation of phenol using the High Performance Liquid Chromatography (HPLC).
Microalgae are generally mass produced in pure culture photobioreactors or in open ponds. While open ponds are generally cheaper to operate from a maintenance standpoint, an issue with them is that open systems allow for external microorganisms to interfere with the desired product yield. Understanding the effect of reactor conditions on co-culture setups of marine microalgae will allow for better design and operation to maximize product yield (in this case, single cell protein). The strains Nannochloropsis gaditana (CCAP649/5) and Tetraselmis chuii (UTEX LB232) are investigated in this study, first characterized separately and then co-cultured together.
Coupled with its superhydrophilicity, Titanium dioxide thin film owes its self-cleaning ability to organic pollutant degradation. Using commercially available titanium dioxide film by the Pilkington Glass, a model organic pollutant - 2-propanol - degradation was investigated under ultraviolet and solar simulated light irradiations. The photo-activities of both Pilkington ActivTM Clear (PAC) and Pilkington ActivTM Blue (PAB) under solar simulated light were comparable. However, irradiation under ultraviolet light enhanced 2-propanol photodegradation with PAC, whereas 2-propanol degradation was significantly reduced for PAB. Possible reasons for these variations were provided based on characterization results from Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Raman Spectroscopy and UV-Vis Spectroscopy. Variation of the degradation product concentration as monitored by Gas Chromatography (GC) is also used to explain the possible mechanism of 2-propanol degradation.
