Development Of Analysis Research Articles

An argument against presenting interval quantifications as a surrogate for the value of evidence

In the various forensic science disciplines, recent analytical developments paired with modern statistical computational tools have led to the proliferation of adhoc techniques for quantifying the probative value of forensic evidence. Many legal and scientific scholars agree that the value of evidence should be reported as a likelihood ratio or a Bayes Factor. Quantifying the probative value of forensic evidence is subjected to many sources of variability and uncertainty. There is currently a debate on how to characterize the reliability of the value of evidence. Some authors have proposed associating a confidence/credible interval with the value of evidence assigned to a collection of forensic evidence. In this paper, we will discuss the reasons for our opinion that interval quantifications for the value of evidence should not be used directly in the Bayesian decision-making process to determine the support of the evidence for one of the two competing hypotheses.

Body mass index: Has epidemiology started to break down causal contributions to health and disease?

To review progress in understanding the methods and results concerning the causal contribution of body mass index (BMI) to health and disease. In the context of conventional evidence focused on the relationship between BMI and health, this review considers current literature on the common, population-based, genetic contribution to BMI and how this has fed into the developing field of applied epidemiology. Technological and analytical developments have driven considerable success in identifying genetic variants relevant to BMI. This has enabled the implementation of Mendelian randomization to address questions of causality. The product of this work has been the implication of BMI as a causal agent in a host of health outcomes. Further breakdown of causal pathways by integration with other "omics" technologies promises to deliver additional benefit. Gaps remain in our understanding of BMI as a risk factor for health and disease, and while promising, applied genetic epidemiology should be considered alongside alternative methods for assessing the impact of BMI on health. Potential limitations, relating to inappropriate or nonspecific measures of obesity and the improper use of genetic instruments, will need to be explored and incorporated into future research aiming to dissect BMI as a risk factor.

Blunt defect assessment in the framework of the failure assessment diagram

In order to reduce over-conservatism in fitness-for-service assessment procedures, experimental evidence and recent analytical developments recognise the importance of considering the actual shape of non-sharp flaws and/or the real geometric constraint conditions at the crack tip. This paper addresses the effect of blunt defects on the structural integrity assessment of reactor pressure vessel (RPV) and pipeline steels. Parametric studies for compact tension specimens with various notch root radii are performed using finite element analysis. The notch fracture toughness, the resistance to the onset of ductile cracking and the J-integral, quantifying the notch driving force, are evaluated. A stress-modified fracture strain model is used as a virtual testing method. The results are analyzed in the framework of the failure assessment diagram (FAD), showing that the existing shape of the FAD is also suitable for assessments of blunt defects and how the concepts introduced can be used to reduce the conservatism in defect assessment, define margins on failure and indicate when plastic collapse is the dominant failure mechanism.

Analysis, occurrence, fate and risks of proton pump inhibitors, their metabolites and transformation products in aquatic environment: A review

Proton pump inhibitors (PPIs) which include omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole, are extensively used for the relief of gastro-intestinal disorders. Despite their high worldwide consumption, PPIs are extensively metabolized in human bodies and therefore are not regularly detected in monitoring studies. Very recently, however, it has been shown that some omeprazole metabolites may enter and are likely to persist in aquatic environment. Hence, to fully assess the environmental exposures and risks associated with PPIs, it is important to better understand and evaluate the fate and behavior not only of the parent compound but also of their metabolites and their transformation products arising from biotic and abiotic processes (hydrolysis, photodegradation, biodegradation etc.) in the environment. In this light, the purpose of this review is to summarize the present state of knowledge on the introduction and behavior of these chemicals in natural and engineering systems and highlight research needs and gaps. It draws attention to their transformation, the increase contamination by their metabolites/TPs in different environmental matrices and their potential adverse effects in the environment. Furthermore, existing research on analytical developments with respect to sample treatment, separation and detection of PPIs and their metabolites/TPs is provided.

Networks in the Social Sciences

While the question of networks have appeared in social sciences since decades, they can be still regarded as one of the significant concepts which grasps the imagination of both theorists and empirical researchers. Because of this interest many different forms of network approaches have been developed. In many cases these theoretical and analytical developments have occurred relatively independently from each other using different vocabularies and research styles. This paper aims to present two prominent network approaches, namely Actor-Network-Theory (ANT) and Social Network Analysis (SNA), in order to highlight the similarities and differences between them. This parallel presentation also allows to map the possible connections between these two separate schools of thought. Consequently, the first and second main sections of the paper introduces ANT and SNA respectively, while the last section of the paper discusses similarities and differences, as well as, possible fruitful convergences between these two.

Analysis and Minimization of Output Current Ripple for Discontinuous Pulse-Width Modulation Techniques in Three-Phase Inverters

This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM) strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−), and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation) to identify the optimal pulse-width modulation (PWM) strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.

A novel, single-layer model for composite plates using local-global approach

Abstract In structural analysis, many components are approximated as plates. More often that not, classical plate theories, such as Kirchhoff or Reissner-Mindlin plate theories, form the basis of the analytical developments. The advantage of these approaches is that they leads to simple kinematic descriptions of the problem: the plate's normal material line is assumed to remain straight and its displacement field is fully defined by three displacement and two rotation components. While such approach is capable of capturing the kinetic energy of the system accurately, it cannot represent the strain energy adequately. For instance, it is well known from three-dimensional elasticity theory that the normal material line will warp under load for laminated composite plates, leading to three-dimensional deformations that generate complex stress states. To overcome this problem, several layer-wise plate theories have been proposed. While these approaches work well for some cases, they often lead to inefficient formulations because they introduce numerous additional variables. This paper presents a novel, single-layer theory using local-global Approach: based on a finite element semi-discretization of the normal material line, the two-dimensional plate equations are derived from three-dimensional elasticity using a rigorous dimensional reduction procedure. Three-dimensional stresses through the plate's thickness can be recovered accurately from the plate's stress resultants.

Experimental evaluation of bed friction and solids transport in steep flume

AbstractExperimental data on bed friction and solids transport in an open‐channel flow at high bed shear are presented in this paper together with a discussion using analytical developments. Experiments were carried out using plastic particles transported in water above an erodible bed in a tilting flume. They confirmed that bed friction is affected by transport of solids for large bed shear stresses in the upper plane bed regime. Similarities in flow conditions were also observed between open‐channel flows in steep slopes with intense solids transport, and stratified flows in slurry pipes. Furthermore, the experiments revealed two different sub‐regimes for the upper plane bed regime in open channels. Formulae for the friction coefficient and the solids flowrate were proposed for an erodible bed with a developed shear layer. Measured velocity distribution indicated a linear velocity profile across a major part of the shear layer.

Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate.

The Early Eocene Climate Optimum (EECO, which occurred about 51 to 53 million years ago), was the warmest interval of the past 65 million years, with mean annual surface air temperature over ten degrees Celsius warmer than during the pre-industrial period. Subsequent global cooling in the middle and late Eocene epoch, especially at high latitudes, eventually led to continental ice sheet development in Antarctica in the early Oligocene epoch (about 33.6 million years ago). However, existing estimates place atmospheric carbon dioxide (CO2) levels during the Eocene at 500-3,000 parts per million, and in the absence of tighter constraints carbon-climate interactions over this interval remain uncertain. Here we use recent analytical and methodological developments to generate a new high-fidelity record of CO2 concentrations using the boron isotope (δ(11)B) composition of well preserved planktonic foraminifera from the Tanzania Drilling Project, revising previous estimates. Although species-level uncertainties make absolute values difficult to constrain, CO2 concentrations during the EECO were around 1,400 parts per million. The relative decline in CO2 concentration through the Eocene is more robustly constrained at about fifty per cent, with a further decline into the Oligocene. Provided the latitudinal dependency of sea surface temperature change for a given climate forcing in the Eocene was similar to that of the late Quaternary period, this CO2 decline was sufficient to drive the well documented high- and low-latitude cooling that occurred through the Eocene. Once the change in global temperature between the pre-industrial period and the Eocene caused by the action of all known slow feedbacks (apart from those associated with the carbon cycle) is removed, both the EECO and the late Eocene exhibit an equilibrium climate sensitivity relative to the pre-industrial period of 2.1 to 4.6 degrees Celsius per CO2 doubling (66 per cent confidence), which is similar to the canonical range (1.5 to 4.5 degrees Celsius), indicating that a large fraction of the warmth of the early Eocene greenhouse was driven by increased CO2 concentrations, and that climate sensitivity was relatively constant throughout this period.

Nonlinear indirect combustion noise for compact supercritical nozzle flows

In this paper, indirect combustion noise generated by the acceleration of entropy perturbations through a supercritical nozzle is investigated in the nonlinear regime and in the low-frequency limit (quasi-static hypothesis). This work completes the study of Huet and Giauque (Journal of Fluid Mechanics 733 (2013) 268–301) for nonlinear noise generation in nozzle flows without shock and particularly focuses on shocked flow regimes. It is based on the analytical model of Marble and Candel for compact nozzles (Journal of Sound and Vibration 55 (1977) 225–243), initially developed for excitations in the linear regime and rederived here for nonlinear perturbations. Full nonlinear analytical solutions are provided in the absence of shock as well as second-order analytical expressions when a shock is present in the diffuser. An analytical evaluation of the shock displacement inside the nozzle caused by the forcing is proposed and maximum possible forcings to avoid unchoke and ‘over-choke’ are discussed. The accuracy of the second-order model and the nonlinear contributions to the generated waves are then addressed. This model is found to be very accurate for the generated entropy wave with negligible nonlinear contributions. Nonlinearities are more visible, but still limited, for the downstream acoustic wave for large inlet Mach numbers. Analytical developments are validated thanks to comparisons with numerical simulations.

Lab-on-a-chip and other miniaturised analytical instruments

Purpose This paper aims to provide details of miniaturised analytical instrument technologies and developments. Design/methodology/approach Following an introduction and historical background, this first considers miniaturised chromatographs and spectrometers based on micro-electromechanical system (MEMS)/micro total analytical system technologies. It then discusses lab-on-a-chip developments with an emphasis on capillary electrophoresis. Developments in the emerging lab-on-paper technology are then considered and are followed by brief concluding comments. Findings This shows that many classes of analytical instruments which offer a number of operational and economic benefits have been miniaturised through the use of microfabrication and other technologies. They are an active field of research and are based on silicon, glass, polymers and even paper and are underpinned by developments in microfluidics and optofluidics and fabrication techniques which include lithography, MEMS and micro-opto-electromechanical system. Originality/value This provides an insight into the rapidly developing field of miniaturised analytical instrument technologies.

A numerical investigation on the eccentricity growth of GNSS disposal orbits

We present the results of an extensive numerical exploration performed on the eccentricity growth in MEO associated with two possible end-of-life disposal strategies for GNSS satellites. The study calls attention to the existence of values of initial inclination, longitude of ascending node, and argument of perigee that are more advantageous in terms of long-term stability of the orbit. The important role of the initial epoch and a corresponding periodicity are also shown. The present investigation is influential in view of recent analytical and numerical developments on the chaotic nature of the region due to lunisolar perturbations, but also for the upcoming Galileo and BeiDou constellations.

Disc-based microarrays: principles and analytical applications.

The idea of using disk drives to monitor molecular biorecognition events on regular optical discs has received considerable attention during the last decade. CDs, DVDs, Blu-ray discs and other new optical discs are universal and versatile supports with the potential for development of protein and DNA microarrays. Besides, standard disk drives incorporated in personal computers can be used as compact and affordable optical reading devices. Consequently, a CD technology, resulting from the audio-video industry, has been used to develop analytical applications in health care, environmental monitoring, food safety and quality assurance. The review presents and critically evaluates the current state of the art of disc-based microarrays with illustrative examples, including past, current and future developments. Special mention is made of the analytical developments that use either chemically activated or raw standard CDs where proteins, oligonucleotides, peptides, haptens or other biological probes are immobilized. The discs are also used to perform the assays and must maintain their readability with standard optical drives. The concept and principle of evolving disc-based microarrays and the evolution of disk drives as optical detectors are also described. The review concludes with the most relevant uses ordered chronologically to provide an overview of the progress of CD technology applications in the life sciences. Also, it provides a selection of important references to the current literature. Graphical Abstract High density disc-based microarrays.

STABILITY INDICATING OPTIMIZED RP-HPLC METHOD APPLYING QBD PRINCIPLES FOR QUANTITATIVE ESTIMATION OF NIMORAZOLE

ICH Q8(R2) guidelines concerning the development of pharmaceutical process following a Quality by Design (QbD) approach can be implemented for analytical method developments. Nimorazole is a hypoxic radiosensitizer used in radiotherapy treatment for squamous cell cancer of the head and neck. The aim of the present work was to develop a simple, robust, optimized and stability indicating reverse phase high performance liquid chromatographic method underlying QbD principles for the estimation of nimorazole in pharmaceutical samples. The objectives were achieved at optimized chromatographic conditions using a column of dimensions, 250 x 4.6 mm, C18 (5 μm) (such as Sunfire C18), using mobile phase comprising a mixture of 51 volumes of 0.01 M KH2PO4 solution and 49 volumes of methanol using flow rate of 1.0 mL per minute, injection volume of 10 μl, column oven temperature at 27°C and 302 nm as detection wavelength. The developed method was found linear over the concentration range of 10-150 ppm with detection and quantitation limit of 2.73 ppm and 8.28 ppm respectively. The retention time of nimorazole is found about 4.9 minutes and the assay observed were 101.60 % and 99.52 % in bulk drug and tablet dosage form respectively. Whilst performing the forced degradation studies to demonstrate the specificity of analytical method, nimorazole suffers much degradation in oxidative, less in basic and least in acidic conditions, while no degradation was observed in thermal and photolytic conditions. The respective degradation products were well resolved from the pure drug. Hence, the method can be successfully employed for quantitative analysis of nimorazole in pharmaceutical samples.

Analytical Dynamics Based Strategy for Acceleration Control of a Car-like Vehicle Motion

The paper addresses a dynamics modeling method dedicated to control design for constrained mechanical systems. The constraints may be material, control or task based, provided that they are specified by algebraic or differential equations. Theoretical analytical and control developments are related to control acceleration and jerk for car-like vehicles. In vehicle dynamics design and control, jerk and acceleration limits are control objectives related to passenger comfort and vehicle performance. Usually, their profiles are assessed experimentally and then incorporated into vehicle controllers. The paper presents a control strategy, which enables specifying desired profiles of acceleration and jerk by constraint equations.

Mass spectrometry of modified RNAs: recent developments.

A common feature of ribonucleic acids (RNAs) is that they can undergo a variety of chemical modifications. As nearly all of these chemical modifications result in an increase in the mass of the canonical nucleoside, mass spectrometry has long been a powerful approach for identifying and characterizing modified RNAs. Over the past several years, significant advances have been made in method development and software for interpreting tandem mass spectra resulting in approaches that can yield qualitative and quantitative information on RNA modifications, often at the level of sequence specificity. We discuss these advances along with instrumentation developments that have increased our ability to extract such information from relatively complex biological samples. With the increasing interest in how these modifications impact the epitranscriptome, mass spectrometry will continue to play an important role in bioanalytical investigations revolving around RNA.

Trapping vibratory energy of main linear structures by coupling light systems with geometrical and material non-linearities

Cubic potential and hysteresis behavior (Bouc–Wen type) of a non-linear energy sink are used to localize the vibratory energy of a linear structure. A general methodology is presented to deal with time evolutionary energy exchanges between two oscillators. Invariant manifold of the system and its stability borders are detected at fast time scale while traced equilibrium and singular points at slow time scale let us predict possible behaviors of the system during its pseudo-stationary regime(s). The paper is followed by an example that considers the Dahl model for representing the hysteresis behavior of the non-linear energy sink. All analytical developments and results are compared with those obtained by direct integration of system equations. Obtained analytical developments can be endowed for designing non-linear energy sink devices with hysteresis behavior to localize vibratory energy of main structures for the aim of passive control, energy harvesting and/or both of them.

Unfreezing Taylor’s Hypothesis for Precipitation

Abstract Since the seminal work of Zawadzki in the seventies, the so-called Taylor’s “frozen” hypothesis has been regularly used to study the statistical properties of rainfall patterns. This hypothesis yields a drastic simplification in terms of symmetry of the space–time structure—the large-scale advection velocity is the conversion factor used to link the time and space autocorrelation functions (ACFs) of the small-scale variability. This study revisits the frozen hypothesis with a geostatistical model. Using analytical developments and numerical simulations tuned on available case studies from the literature, the role of large- and small-scale rainfall kinematics on the properties of the space–time ACF and associated fluctuations is investigated. In particular, the merits and limits of the ACF signature classically used to test the frozen hypothesis are examined. The conclusion is twofold. Taylor’s hypothesis, understood as the quest for a space–time symmetry in rain field variability, remains important in hydrometeorology four decades after the pioneering work of Zawadzki. The frozen hypothesis, introduced for simplification purposes, appears difficult to check and too constraining. The methods proposed to check the hypothesis rely too directly on the use of the advection velocity as a space–time conversion factor instead of contemplating the ACF signature more globally. The model proposed that using two characteristic velocities instead of one appears more flexible to fit the ACF behaviors presented in the literature. This remains to be checked over a long-term high-resolution dataset.

Delayed-feedback vibration absorbers to enhance energy harvesting

Recovering energy from ambient vibrations has recently been a popular research topic. This article is conceived as a concept study that explores new directions to enhance the performance of such energy harvesting devices from base excitation. The main idea revolves around the introduction of delayed feedback sensitization (or tuning) of an active vibration absorber setup. To clarify the concept, the Delayed Resonator theory is reviewed and its suitability for energy harvesting purposes is studied. It is recognized that an actively tuned and purely resonant absorber is infeasible for such applications. The focus is then shifted to alternative tuning schemes that deviate from resonance conditions. Also called Delayed Feedback Vibration Absorbers, these devices may indeed provide significant enhancements in energy harvesting capacity. Analytical developments are presented to study energy generation and consumption characteristics. Effects of excitation frequency and absorber damping are investigated. The influences of time-delayed feedback on the stability and the transient performance of the system are also treated. The analysis starts from a stand-alone absorber, emulating seismic mass type harvesters. The work is then extended to vibration control applications, where an absorber/harvester is coupled with a primary structure. The results are demonstrated with numerical simulations on a case study.

Wave mode diffusion and propagation in structural wave guide under Varying Temperature

A numerical approach is presented to study the guided wave propagation through periodic specimen with thermal dependence of material properties. There is a great interest in extending the skills of the wave finite element (WFE) method to figure out the variations in the wave propagation properties due to temperature fluctuations. Thermal effects on the dispersion curves thereby on group velocity are discussed. Comparisons between numerical results and analytical developments for various temperatures are given to prove the effectiveness of the proposed approach to predict the sensitivity of guided wave propagation characteristics in presence of temperature variations.