Dynamic Lab Research Articles

Futuristic study on seismic response analysis of North Indian soils– A sustainable approach

India's growing population and extensive unscientific structures put the country at risk of suffering major casualties during earthquakes. To make buildings more earthquake-resistant, and develop safe and durable structures for future, we need seismic sustainability. For this purpose, Cities should adopt ‘seismic microzonation’, which includes Site response analysis (SRA). In this paper, SRA for eight places in Varanasi (India) was performed using the equivalent linear technique subjected to four significantly different strong motions (Bhuj, Uttarkashi, Chamba, and Kobe motion). Geotechnical data from various government and private entities have been gathered for this purpose. Analysis has been conducted using equivalent linear approach in DEEPSOIL software. The results of the study have been formulated in terms of surface time histories, response spectra, Fourier spectra and PGA along the depth. These findings may be applied to dynamic analysis and structural design, as well as the preparation of advanced dynamic lab tests. Furthermore, sites in Varanasi have been found to considerably enhance ground motion, thus a site-specific design approach must be implemented for important constructions.

Enhancing sEMG-Based Finger Motion Prediction with CNN-LSTM Regressors for Controlling a Hand Exoskeleton

In recent years, the number of people with disabilities has increased hugely, especially in low- and middle-income countries. At the same time, robotics has made significant advances in the medical field, and many research groups have begun to develop low-cost wearable solutions. The Mechatronics and Dynamic Modelling Lab of the Department of Industrial Engineering at the University of Florence has recently developed a new version of a wearable hand exoskeleton for assistive purposes. In this paper, we will present a new regression method to predict the finger angle position of the first joint from the value of the sEMG of the forearm and the previous position of the finger itself. To acquire the dataset necessary to train the regressor a specific graphical user interface was developed which was able to acquire sEMG data from a Myo armband and the finger position from a Leap Motion Controller. Two long short-term memory (LSTM) models were compared, one in its standard configuration and the other with a convolutional layer, yielding significantly better performance for the second one, with an increase in R2 coefficient from an average value of 0.746 to 0.825, leading to the conclusion that a convolutional layer could increase performance when few sensors are available.

A Subjective Study on the Effects of Dynamic Virtual Chemistry Laboratory in a Secondary School Education

Virtual chemistry laboratories (VCLs) are the alternative solutions of the physical laboratories, where students can virtually conduct their experiments with a lower cost, and in an efficient and safer way. Considering the importance of technology-enhanced learning and that of the experimental study, several VCLs have been proposed. However, the existing VCLs are static and only provide the simulation of pre-defined experiments, procedures, or safety procedures and cannot be adapted according to the students’ level or new experimental tasks. In this paper, we proposed a dynamic virtual chemistry lab (DVCL) where instructors or experts are allowed to add a new chemical experiment by adding its apparatus, chemicals, glassware, and mechanism or add something new to its properties. We conducted a subjective study with field experts to investigate the effect of proposed DVCL in secondary school chemistry education. During evaluation, twenty-seven field experts were participated and evaluated the proposed DVCL with system usability scale (SUS)-questionnaire and by a simple questionnaire. The results showed that the proposed DVCL is very helpful for students’ performance and mental modeling and also for effortlessly uplifting their knowledge for hands-on experiments.

An innovative ballasted track utilizing stabilized clayey subgrade

The traditional ballasted tracks have been used widely in railway transportation infrastructure. Construction of ballasted tracks on the clayey soft subgrade causes high settlement and low bearing capacity. Significant maintenance cost and time-consuming operation have been encountered due to presence of clay. Different methods of soil stabilization have been presented in literature. Using road construction experience with Royal Road Product (RRP235 Special), as an innovative method for the first time, the layers underneath the sleeper have been replaced with the clayey subgrade stabilized with RRP 235 special. A series of static and dynamic lab experiments such as Maximum Compaction test, California Bearing Ratio, Unconfined Compressive Strength, Brazilian Indirect Tensile test, Direct Shear Strength, and Uniaxial Cyclic tests were carried out. Samples with different dosages of additive were made, and an optimal percentage was found. As the result, the sample with 0.15 lit/m^3 RRP235 Special was determined as the suitable dosage in terms of mechanical and physicaltests, while only in the Maximum Compaction test, by increasing the additive, the optimum water content decreased.

Career Ladder: Kelly Chibale

1964 Humble beginnings Kelly Chibale was born in Zambia in a remote village called Muwele. He grew up without electricity or running water, and he had no exposure to science early on. In seventh grade, he failed his exams and had to repeat that year of schooling. “That failure was a turning point,” he says. He decided that he did not want to continue to live in poverty. Education was a way of getting out of poverty, he says. “Our role models in those days were people who went to school.” His first exposure to science, specifically chemistry, was in high school. Chibale says his dynamic chemistry teacher and learning lab techniques such as titration sparked his interest in chemistry. 1983 Synthesizing his degree Chibale went to the University of Zambia to pursue a bachelor’s degree in chemistry. “It was when I was an undergraduate that I really began to

Validation of a Multilayered Analog Model Integrating Crust‐Mantle Visco‐Elastic Coupling to Investigate Subduction Megathrust Earthquake Cycle

AbstractWe have developed a scaled analog model of a subduction zone simulating seismic cycle deformation phases. Its rheology is based on multilayered visco‐elasto‐plastic materials to account for the mechanical behavior of a continental lithospheric plate overriding a subducting oceanic plate. The seismogenic zone displays unstable slip behavior, extending at depth into a weak interface with stable slip properties. The model succeeds in reproducing interseismic phases interrupted by coseismic ruptures and followed by after‐slip. The experimental data catalog shows a broad variability of slip events from aseismic slow slips to fast dynamic lab quakes. Results also show the occurrence of both isolated and precursory slow‐slip events arising before the mainshocks. Given the absence of fluids in the model, the broad variability in slip event velocity can be attributed to fault roughness complexity. The model rheology induces also a key visco‐elastic coupling between the elastic overriding plate and the mantle wedge allowing, for the first time, to reproduce experimentally a realistic postseismic visco‐elastic relaxation phase. Preliminary results reveal that the tectonic loading rate modulates this visco‐elastic coupling. A low loading rate weakens it, which increase the amount of storable interseismic elastic deformation, and favors the occurrence of large megathrust events. A high loading rate strengthens it, which minimize the accumulation of interseismic elastic deformation, the slip‐event sizes, and promote aseismic creep. This new scaled‐analog subduction model is a complementary tool to investigate earthquake mechanics and improve the interpretation of geodetic and seismological records.

Detection of Friction Stir Welding Defects of AA1060 Aluminum Alloy Using Specific Damping Capacity.

The demand for nondestructive testing has increased, especially in welding testing. In the current study, AA1060 aluminum plates were jointed using the friction stir welding (FSW) process. The fabricated joints were subjected to free vibration impact testing in order to investigate the dynamic properties of the welded joint. Damping capacity and dynamic modulus were used in the new prediction method to detect FSW defects. The data acquired were processed and analyzed using a dynamic pulse analyzer lab shop and ME’Scope’s post-processing software, respectively. A finite element analysis using ANSYS software was conducted on different types of designed defects to predict the natural frequency. The results revealed that defective welded joints significantly affect the specific damping capacity. As the damping ratio increased, so did the indication of opportunities to increase the presence of defects. The finite element simulation model was consistent with experimental work. It was therefore revealed that natural frequency was insufficient to predict smaller defects.

NOx instrument intercomparison for laboratory biomass burning source studies and urban ambient measurements in Albuquerque, New Mexico

ABSTRACTUnderstanding nitrogen oxides (NOx = NO + NO2) measurement techniques is important as air-quality standards become more stringent, important sources change, and instrumentation develops. NOx observations are compared in two environments: source testing from the combustion of Southwestern biomass fuels, and urban, ambient NOx. The latter occurred in the urban core of Albuquerque, NM, at an EPA NCORE site during February–March 2017, a relatively clean photochemical environment with ozone (O3) <60 ppb for all but 6 hr. We compare two techniques used to measure NOx in biomass smoke during biomass burning source testing: light absorption at 405 nm and a traditional chemiluminescence monitor. Two additional oxides of nitrogen techniques were added in urban measurements: a cavity attenuated phase shift instrument for direct NO2, and the NOy chemiluminescence instrument (conversion of NOy to NO by molybdenum catalyst). We find agreement similar to laboratory standards for NOx, NO2, and NO comparing all four instruments (R2 > 0.97, slopes between 0.95 and 1.01, intercepts < 2 ppb for 1-hr averages) in the slowly varying ambient setting. Little evidence for significant interferences in NO2 measurements was observed in comparing techniques in late-winter urban Albuquerque. This was also confirmed by negligible NOz contributions as measured with an NOy instrument. For the rapidly varying (1-min) higher NOx concentrations in biomass smoke source testing, larger variability characterized chemiluminescence and absorption instruments. Differences between the two instruments were both positive and negative and occurred for total NOx, NO, and NO2. Nonetheless, integrating the NOx signals over an entire burn experiment and comparing 95 combustion experiments, showed little evidence for large systematic influences of possible interfering species biasing the methods. For concentrations of <2 ppm, a comparison of burn integrated NOx, NO2, and NO yielded slopes of 0.94 to 0.96, R2 of 0.83 to 0.93, and intercepts of 8 to 25 ppb. We attribute the latter, at least in part, to significant noise particularly at low NOx concentrations, resulting from short averaging times during highly dynamic lab burns. Discrepancies between instruments as indicated by the intercepts urge caution with oxides of nitrogen measurements at concentrations <50 ppb for rapidly changing conditions.Implications: Multiple NOx measurement methods were employed to measure NOx concentrations at an EPA NCORE site in Albuquerque, NM, and in smoke produced by the combustion of Southwestern biomass fuels. Agreement shown during intercomparison of these NOx techniques indicated little evidence of significant interfering species biasing the methods in these two environments. Instrument agreement is important to understand for accurately characterizing ambient NOx conditions in a range of environments.

Earthquake Response Analysis of Sites in State of Haryana using DEEPSOIL Software

Earthquake response analysis has been carried out for various locations in the State of Haryana (India) adopting the equivalent linear approach. For this purpose, geotechnical data have been collected from different government and private organizations. Based on the provisions of National Earthquake Hazards Reduction Program (NEHRP), all the sites have been classified using average N-value (N30) for the soil profile. The shear modulus (Gmax) values of the layers in a soil profile have been estimated using standard correlations. Cyclic Response has been accounted for using the standard shear modulus degradation and damping curves. Time histories from Himalayan Thrust System have been used as an input and soil amplification has been estimated at the surface using DEEPSOIL software. The results of the study have been formulated in terms of soil amplification map, response spectra, PGA along the depth, surface time histories and strain along the depth. These results can be used for dynamic analyses and design of structures, planning of advanced dynamic lab test etc. Moreover, it has been observed that sites in Haryana can significantly amplify ground motions and hence a site-specific design approach must be adopted for important structures.

Endocrine and metabolic assessment in adults with Langerhans cell histiocytosis

ContextDiabetes insipidus (DI) is one of most common complications of Langerhans cell histiocytosis (LCH) but prevalence of anterior pituitary deficiencies and metabolic alterations have not been clearly defined yet. ObjectivesEvaluate prevalence of endocrine and metabolic manifestations in a cohort of patients affected by Pulmonary LCH. MethodsObservational cross-sectional study on 18 adults (7 M/11 F, 42±12years) studied for complete basal and dynamic endocrine lab tests and glucose metabolism. ResultsHypothalamic-pituitary endocrine alterations were found in 9 patients: 9 had DI, 5 Growth Hormone Deficiency (GHD), 5 central hypogonadism, 3 central hypothyroidism and 1 central hypoadrenalism. Hyperprolactinemia and hypothalamic syndrome were found in 2 patients each. All these central endocrine alterations were always associated to DI. Five of the 10 MRI performed showed abnormalities. Prevalence of obesity and glucose alterations (either DM or IFG/IGT) were respectively 39% and 33%, higher than expected basing on epidemiological data on general Italian population. Multi-system-LCH without risk-organ involvement (LCH MS-RO−) seems to have slightly higher prevalence of insulin resistance, glucose alterations and metabolic syndrome than LCH with isolated lung involvement (LCH SS lung+). A papillary BRAFV600E positive thyroid carcinoma was diagnosed in one patient. ConclusionsThe presence of anterior pituitary deficiencies should be systematically sought in all LCH patients with DI both at diagnosis and during the follow-up by basal and dynamic hormonal assessment. Patients with pulmonary LCH, particularly those with MS disease, have a worse metabolic profile than general population. Occurrence of papillary thyroid carcinoma has been reported.

Itom: an open source metrology, automation, and data evaluation software.

Modern optical sensors and measurement systems usually are a powerful combination of optical elements, active hardware components like actuators or sensing devices as well as a sophisticated control software and data evaluation algorithms. In order to develop and operate such systems, it is necessary to have a flexible, intuitive, and fast underlying software framework that also allows for rapid prototyping of a sensor in a dynamic lab environment. This software must be able to control and communicate with all necessary hardware devices and has to provide all the highly performant evaluation, data, and image processing algorithms required. In this publication, we want to present the open source measurement and data evaluation software suite itom, which has been designed considering the denoted requirements and whose development began in 2011.

A dynamic network model of translatorial cognition and action

As an interdisciplinary research endeavor into the foundations of human and artificial intelligence, cognitive science has substantial contributions to offer to the field of translation studies. Like any other explanatory approach to socially embedded and organized behavior, cognitive science deals with hard-to-resolve dichotomies such as static versus dynamic approaches, lab- or field-based methods or the opposing views of individual and social explanations. To introduce current theoretical developments from cognitive science, we offer a conceptual framework that conceives these apparent dichotomies as complementary perspectives and helps us to cope with the nested and embedded nature of translatorial cognition and action. For this purpose, we specify a dynamic network analytical model which treats acts of individual cognition and (inter)action as being constitutively interwoven with their social, symbolic and material environments and combine all its elements into a coherent dynamic process perspective. In our outlook, we discuss this extended model’s potential to structure the ongoing theoretical debate on translation process research, as well as its ability to serve as a scaffold for defining and contextualizing empirical studies and thus guiding research into the complex dynamics of translation as a situated activity.

Forward-Looking: Measuring Attention Allocation for Evaluating Supervisory Control in a Complex and Dynamic Lab System

Abstract The objective of the present study was to identify suitable eye movement parameters to measure and evaluate human operators' attention allocation behavior in our complex and dynamic lab system. This supervisory control lab system comprises a human operator and a microworld including the pursuit tracking performance of two other participants. Based on a discussion of approaches of research projects related to our lab system, several parameters were selected to investigate human operators' eye movements. These operators had to optimize the tracking performance of the other participants by the use of a specific interface. We examined the relationship between these eye movement parameters and two control action variables reflecting human operators' system understanding. The results indicate that adequate eye movement parameters could be identified in this first approach of evaluating human operators' attention allocation in our lab system.

Use of ultrasonic waves in sub-cooled boiling

This work focuses on the use of ultrasounds in heat transfer fields. Under particular conditions, ultrasonic waves induce a convection coefficient increase. This initial research work, indicates that there are some practical applications in the cooling of the latest generation electronic components.In the first part of this paper, some background on this subject is reported. The ultrasound's influence on heat transfer rate has been observed since the 60's: different authors studied the cooling effect due to ultrasonic waves from different heat transfer regimes. The most investigated configuration was a thin platinum wire immersed in water. Later, a bibliographic research on possible practical applications of ultrasounds was carried out. This research focused in particular on the issue for 3D highly integrated electronic components. For these systems the thermal problem is a major challenge, because they cannot exceed critical temperatures, after which they could be damaged irreversibly. On the basis of our experimental results, ultrasounds could represent a valid means to overcome these thermal problems.Finally, the paper presents a series of experiments performed in the Thermal-Fluid- Dynamic Lab at the Energy and Engineering Systems Department of the University of Pisa. The experiments provide systematic evidence of ultrasonic waves effects, on free convection heat transfer, from a heated circular cylinder to sub-cooled water, at atmospheric pressure. Many variables involved in the heat transfer rise were tested, for example: the ultrasonic generator's power, the position of the heater inside the ultrasonic tank, the variation of the water sub-cooling degree, as function of the heat flux needed dissipating. The aim of the experiment was to find out the set of optimal conditions, in order to successively apply all the results to real packaging systems, as mentioned before. The maximum increase in the heat transfer coefficient, due to ultrasonic waves, was 57%.

Development of high-speed railway vehicle derailment simulation – Part II: Exploring the derailment mechanism

Based on the exactly solution for the wheel/rail contact point and the contact force, a vehicle/rail coupling model for analyzing dynamic derailment is developed in MATLAB as DDSHV (Dynamic Derailment Simulation for High-speed Vehicle). The calculation process of the simulation system is presented in detail, and the best solution conditions are also discussed to quickly obtain results. Two common types of dynamic derailment are studied in DDSHV. There exists a critical point in the process of wheel climb, and the dynamic weakening effect will promote the wheel-climbing rail. Meanwhile, some main factors, such as the speed, the rail condition and the wheel unload rate, have been studied on the dynamic weakening effect. The collision speed of the wheelset is the most important factor affecting impact derailment. As time becomes shorter, the collision can be investigated using LS-DYNA. The results confirm the equation for the critical impact speed used in this paper. DDSHV can also be used to find the vehicle running stability. Through the design of uplink and downlink algorithms, two critical running speeds, the critical speed and the nonlinear critical speed have been found. Yet, the changes in suspension parameters will directly influence these critical speeds. Therefore, an accurate configuration in vehicle will help to reduce the disturbances while an inaccurate configuration may lead to an incident. Although it is dangerous and difficult to make a derailment online test, the effectiveness of DDSHV has been verified by the known dynamic cases and lab tests. In conclusion, DDSHV has assisted in understanding the process of derailment, finding the important factors affecting derailment and exploring the mechanism of dynamic derailment.

A roll of the dice

For some, a lack of tenure creates a dynamic lab environment. For others, it's a gamble not worth taking.

Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

Design, analysis and testing of a smart fin

The paper presents a design concept for a control fin usually used in airborne vehicles such as UAV’s, Micro UAV’s and missiles. The research presents the design of a smart fin with integral piezoelectric actuators embedded in the airfoil skin. Electric field applied to the actuators would twist the airfoil leading to a change of the angle of attack . The study presents, analyze and demonstrates various lamination and actuation methods including a parametric performance investigation by finite elements models and closed form analytical model. The design and the theoretical results are verified by a manufactured smart wing demonstrator subjected to series of static and dynamic lab tests.

Seismic Microzonation and Estimation of Earthquake Loss Scenarios: Integrated Risk Mitigation Project of Bogotá, Colombia

The Universidad de los Andes and the National Institute of Geosciences INGEOMINAS, with the financial support of the national and the municipal governments, have been executing studies to evaluate the seismic hazard and the urban seismic risk for three hypothetical earthquakes that could strike Bogotá, the capital city of Colombia. After having obtained results related to soil amplification using soil dynamic lab studies, analysis of strong-motion records of recent earthquakes and microtremor measurements in a wide area of Bogotá, the study of different scenarios of losses were estimated for different types of buildings and lifelines systems. These earthquake loss estimations have been used by national and local disaster preparedness authorities to design emergency response plans for public information and for educational activities. New requirements are being studied for urban planning, updating the earthquake resistance construction code and for the reinforcement of the seismic rehabilitation of key buildings.

Boundary-Layer Separation on Slender Cones at Angle of Attack

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