scholarly journals Experimental Comparison of Field and Accelerated Random Vertical Vibration Levels of Stacked Packages for Small Parcel Delivery Shipments

2021 ◽  
Vol 11 (7) ◽  
pp. 2927
Author(s):  
Bence Molnár ◽  
Péter Böröcz
Keyword(s):  
Vertical Vibration ◽  
Experimental Comparison ◽  
Shopping Malls ◽  
Time Data ◽  
Worst Case ◽  
Power Spectral ◽  
Online Stores ◽  
Vibration Simulation ◽  
To Receive ◽  
Phase Motion

In the last decade, there has been a significant increase in parcel delivery shipments all over the world due to online stores and consumer demand to receive the products in a shorter period of time. It is especially true when situations like COVID-19 limits personal purchases in shopping malls as well as grocery and pharmaceutical stores. This often means that courier operators try to deliver packages utilizing vehicles with racks or shelves, which during the COVID-19 epidemic are not there anymore. This study measured the vertical vibration levels that occur in stacked parcels during express delivery versus the simulation technique in the laboratory. The goal of this paper was to measure and compare the vibration levels between laboratory practice and field transportation. For the measurement a three-layer stacked unit was built to observe the vibration levels on different road conditions in a parcel delivery vehicle and ASTM vibration profile (ASTM International). Then the measured acceleration-time data were analyzed in terms of power spectral densities (PSD) and the presented statistical data provided an understanding of the variability of intensity in different levels in stacked unit. The results showed that the vibration level increases in the stacked load upwards and with worse road conditions, but even in the worst case it did not reach those vibration levels that the laboratory test showed. Moreover, the layers of the stacked unit are in out-of-phase motion in the field, while the stacked unit in the vibration simulation usually is in-phase motion. Results indicate that the proposed vibration simulation does not correlate well with typical field vibration. This is fundamentally true as during a forced vibration created by a single-axis shaker, do not account for additional inputs occurring simultaneously creating an off-balance to the loads and as a result are less severe than simulated conditions. These findings are limited to single axis vibration simulation and unsecured loads.

scholarly journals Advancing Clinical Cohort Selection with Genomics Analysis on a Distributed Platform

2019 ◽  
Author(s):  
Jaclyn Marjorie Smith ◽  
Melvin Lathara ◽  
Hollis Wright ◽  
Brian Hill ◽  
Nalini Ganapati ◽  
...  
Keyword(s):  
Precision Medicine ◽  
Large Scale ◽  
Linear Time ◽  
Distributed Storage ◽  
Treatment Options ◽  
Ease Of Use ◽  
Time Data ◽  
Worst Case ◽  
Research Perspective ◽  
Medicine Analysis

Abstract Background The affordability of next-generation genomic sequencing and the improvement of medical data management have contributed largely to the evolution of biological analysis from both a clinical and research perspective. Precision medicine is a response to these advancements that places individuals into better-defined subsets based on shared clinical and genetic features. The identification of personalized diagnosis and treatment options is dependent on the ability to draw insights from large-scale, multi-modal analysis of biomedical datasets. Driven by a real use case, we premise that platforms that support precision medicine analysis should maintain data in their optimal data stores, should support distributed storage and query mechanisms, and should scale as more samples are added to the system. Results We extended a genomics-based columnar data store, GenomicsDB, for ease of use within a distributed analytics platform for clinical and genomic data integration, known as the ODA framework. The framework supports interaction from an i2b2 plugin as well as a notebook environment. We show that the ODA framework exhibits worst-case linear scaling for array size (storage), import time (data construction), and query time for an increasing number of samples. We go on to show worst-case linear time for both import of clinical data and aggregate query execution time within a distributed environment. Conclusions This work highlights the integration of a distributed genomic database with a distributed compute environment to support scalable and efficient precision medicine queries from a HIPAA-compliant, cohort system in a real-world setting. The ODA framework is currently deployed in production to support precision medicine exploration and analysis from clinicians and researchers at UCLA David Geffen School of Medicine.

scholarly journals Analysing Random Vibration of KLT Box during Transporting by Finite Element Method

10.29007/b1th ◽  
2022 ◽  
Author(s):  
Cong Hoa Vu ◽  
Ngoc Thien Ban Dang
Keyword(s):  
Finite Element ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Automotive Industry ◽  
Random Vibration ◽  
Element Model ◽  
Vibration Testing ◽  
Time Data ◽  
Power Spectral ◽  
The Impact

Today, freight is an extremely important industry for the world we are living. Fast transportation, large volume...will optimize the cost, time and effort. Besides, ensuring the products safety is a matter of concern. During transporting, it is inevitable that the vibration caused by the engine, rough road surface...the cargo inside can be damaged. Automobile industries have prime importance to vibration testing. Sine vibration testing is performed when we have been given with only one frequency at given time instant. Trend to perform random vibration testing has been increased in recent times. As random vibration considers all excited frequencies in defined spectrum at known interval of time, it gives real-time data of vibration severities. The vibration severity is expressed in terms of Power Spectral Density (PSD). KLT box is an industrial stacking container conforming to the VDA 4500 standard that was defined by German Association of the Automotive Industry (VDA) for the automotive industry. The aim of this paper is study about random vibration and power spectral density analysis, how it can be used to predict the impact of hash road to the KLT box on container / truck during transportation. Finite element model is developed in ANSYS, modal analysis and random vibration analysis were done.

scholarly journals Effect of the Anti-Yaw Damper on Carbody Vertical Vibration and Ride Comfort of Railway Vehicle

2020 ◽  
Vol 10 (22) ◽  
pp. 8167
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică
Keyword(s):  
Ride Comfort ◽  
Vertical Vibration ◽  
Theoretical Research ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
Damping Force ◽  
Comfort Index ◽  
Lateral Vibrations ◽  
Power Spectral ◽  
Vertical Vibrations

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Evaluating the accuracy of biodiversity changes through geologic times: from simulation to solution

Paleobiology ◽  
2017 ◽  
Vol 43 (4) ◽  
pp. 667-692 ◽  
Author(s):  
Corentin Gibert ◽  
Gilles Escarguel
Keyword(s):  
Discrete Time ◽  
Continuous Time ◽  
Simple Algorithm ◽  
Time Discretization ◽  
Time Interval ◽  
Taxonomic Richness ◽  
Time Data ◽  
Worst Case ◽  
Data Set ◽  
Reconstructed Signal

AbstractEstimating biodiversity and its variations through geologic time is a notoriously difficult task, due to several taphonomic and methodological effects that make the reconstructed signal potentially distinct from the unknown, original one. Through a simulation approach, we examine the effect of a major, surprisingly still understudied, source of potential disturbance: the effect of time discretization through biochronological construction, which generates spurious coexistences of taxa within discrete time intervals (i.e., biozones), and thus potentially makes continuous- and discrete-time biodiversity curves very different. Focusing on the taxonomic-richness dimension of biodiversity (including estimates of origination and extinction rates), our approach relies on generation of random continuous-time richness curves, which are then time-discretized to estimate the noise generated by this manipulation. A broad spectrum of data-set parameters (including average taxon longevity and biozone duration, total number of taxa, and simulated time interval) is evaluated through sensitivity analysis. We show that the deteriorating effect of time discretization on the richness signal depends highly on such parameters, most particularly on average biozone duration and taxonomic longevity because of their direct relationship with the number of false coexistences generated by time discretization. With several worst-case but realistic parameter combinations (e.g., when relatively short-lived taxa are analyzed in a long-ranging biozone framework), the original and time-discretized richness curves can ultimately show a very weak to zero correlation, making these two time series independent. Based on these simulation results, we propose a simple algorithm allowing the back-transformation of a discrete-time taxonomic-richness data set, as customarily constructed by paleontologists, into a continuous-time data set. We show that the reconstructed richness curve obtained this way fits the original signal much more closely, even when the parameter combination of the original data set is particularly adverse to an effective time-discretized reconstruction.

Why NASA may be legally required to sterilize Mars samples to protect Earth's biosphere - 19 years minimum until ready to receive unsterilized samples with existing laws - advantages of orbits above GEO for preliminary telerobotic study instead

2020 ◽  
Author(s):  
Robert Walker
Keyword(s):  
Worst Case ◽  
Sample Return ◽  
Planetary Protection ◽  
Blue Green Algae ◽  
Life On Mars ◽  
Previous Sample ◽  
Laplace Plane ◽  
Space Colonization ◽  
To Receive

NASA plans to return a sample from Mars in the 2020s. However they have not yet started on the legal process to return such a sample safely. There are many laws that already exist that protect Earth’s biosphere. Previous sample return studies have shown that we need to build a sample receiving facility to prevent adverse changes to the environment of Earth from a sample return. This paper examines the timescale based on an end to end requirement, that NASA are required to know what it is they need to build before approving funds for the build. This will not be known until the end of the legal process.We find that it is not possible, with current laws and technology, to have a facility ready to receive unsterilized samples on this timescale. However we find that it is possible to sterilize the samples sufficiently for planetary protection requirements while preserving both astrobiological and geological interest. We also propose as an alternative to return the sample to an orbit in the Laplace plane above GEO, as optimal for protection of Earth, the Moon, and other satellites. This will not delay the geological studies as sterilized subsamples can be returned immediately, and it will permit study of unsterilized material in situ telerobotically. We also look at particular worst case scenarios, which have not been considered in detail before, such as the return of a mirror life blue-green algae, capable of living on Mars and almost anywhere on Earth. We suggest that it is a high priority to determine whether Martian life can be safely mixed into the terrestrial biosphere, and to learn what safety protocols are needed to return it safely. We find that there could be life on Mars that can never be mixed into Earth’s biosphere safely. Finding the answers to this should be a top priority for both scientists and space colonization enthusiasts as the future possibilities, and opportunities, that are open to us depend on whether there is life on Mars and what its nature is.

scholarly journals Vibration transmission simulation model of a seated vehicle passenger

2021 ◽  
Vol 2120 (1) ◽  
pp. 012009
Author(s):  
I Ho ◽  
N Z Abu Bakar
Keyword(s):  
Simulation Model ◽  
Human Body ◽  
Ride Comfort ◽  
Real Life ◽  
Vertical Vibration ◽  
Suspension System ◽  
Human Body Model ◽  
Peak Displacement ◽  
Moving Vehicle ◽  
Vibration Simulation

Abstract The paper presents development of vertical vibration simulation for a seated passenger in a moving vehicle is resulting from the bounce effect of the vehicle under various conditions. Although extensive research has been conducted in this field of study, the existing analysis were conducted on either the suspension of vehicle or the human body and not both. In this paper, the simulation model consists of three sub-systems, namely, vehicle suspension, seat suspension and human body model in which the vertical vibration is transmitted. By incorporating these sub-systems into the simulation, a correlation between mechanical and biological aspects can be formed between the three sub-systems. The transmission of vertical vibration in the validated simulation model provides a more realistic approach which can result to a better comparison to the real-life scenario. Parametric analysis of passive suspension system shows that lower mass ratio, higher stiffness ratio and lower damping coefficient results in better ride comfort. The incorporation of variable damper into the suspension system shows significant improvement in settling time, peak displacement and velocity, lesser discomfort rating and higher safety in passenger body.

scholarly journals Experimental Comparison of Energy Generation between Conventional and Wavy Leading Edge Blades in HAWT

2020 ◽  
pp. 441-446
Author(s):  
Santiago Bernal-del Río ◽  
◽  
Gilberto Osorio-Gómez
Keyword(s):  
Wind Turbine ◽  
Energy Production ◽  
Leading Edge ◽  
Energy Generation ◽  
Research Field ◽  
Experimental Comparison ◽  
Time Data ◽  
Horizontal Axis Wind Turbine ◽  
Functional Models ◽  
Fundamental Research

Horizontal Axis Wind Turbine (HAWT) is one of the most important devices for electricity generation from Wind Energy, and design of new blades has become a fundamental research field to improve the efficiency and to reduce cost of this system. This article presents a preliminary comparison between two micro Wind Turbines (WT), one with standard blades and another one with Wavy Leading Edge (WLE) morphology, inspired by the flippers of the humpback whale, to work at low-speed wind conditions. To perform a correct validation, the authors propose a four steps approach for the design, manufacture and test of a WT. First, the design of the blade, followed by the design of the Wind Turbine (WT). Next step is the manufacture of two functional models, one with WLE and another with standard blades, to make a relative comparison, and, finally, the acquisition of real-time data from these systems for the corresponding analysis in terms of energy generation. Results show that the WLE has an increase of over 20% in energy production in all the tests that were performed, with respect to the standard blade.

Sign in / Sign up

Export Citation Format

Share Document