Typical Gauge Research Articles

Predictive algorithm of instrument health condition based on linear regression and radial basis function neural network

Abstract Enterprises and institutions engaged in social production activities need to apply for mandatory verification of general instruments and meters on production equipment according to law, and its verification period is determined by national or local verification and calibration procedures, but the health condition in the calibration intervals is difficult to know. To improve equipment reliability, this paper relies on the linear regression model to research the health condition of general instruments and meters, uses MATLAB tools to analyze the data samples of typical equipment pressure gauge, and combines radial basis function neural network to form a complete algorithm, and finally provides a complete implementation scheme for the health condition prediction of general instruments and meters in service.

Judging Rainfall Intensity from Inter-Tip Times: Comparing ‘Straight-Through’ and Syphon-Equipped Tipping-Bucket Rain Gauge Performance

The inter-tip times (ITTs) of tipping-bucket rain gauges (TBRGs) potentially provide the highest-resolution intensity data that can be acquired from this type of gauge. At an intensity of 100 mm h−1, a typical gauge with a sensitivity of 0.2 mm of rainfall would be expected to tip every 7.2 s. However, TBRGs are often equipped with syphons to reduce the dynamic calibration error that results from continued (and unmeasured) inflow to a bucket as it tips. This increases the accuracy of rainfall depth recording, but the time to fill and empty the syphon can reduce the ability of a TBRG to respond to (and for the ITTs to reflect) short-term intensity fluctuations. This ability is already limited by the discretisation arising from the filling and emptying of the buckets themselves. Laboratory tests with controlled water inflow rates were performed using two high-quality TBRGs, one a ‘straight-through’ design and the other syphon-equipped. These confirmed that at all intensities at which the syphon operates, a regular sequence of fixed-duration ITTs (such as the 7.2 s mentioned above) does not occur. Rather, the ITTs are perturbed by the syphon cycling. The gauges were also co-located in the field and linked to carefully synchronised event data loggers. Data collected during several rainfall events revealed differences in the ITTs and again confirm that the ITT sequence of a syphon-equipped TBRG exhibits artefacts related to syphon operation that are not present in the ‘straight-through’ data. These artefacts can result in ITT differences of many minutes, depending on the rainfall intensity and are problematic for the use of ITTs to estimate intensity. Peaks and troughs in the intensity profile also differed between the two gauges. It is recommended that in the application of TBRGs for studies where short-term intensity data are required, ‘straight-through’ gauges should be used, and syphon-equipped gauges should be avoided.

Is gauge mediation in the swampland?

We note that the typical gauge mediation of supersymmetry breaking is in tension with the global limit of the festina lente swampland bound. The alternatives are mediation/breaking schemes that decouple together with gravity, as for example gravity mediation, for which we highlight some basic phenomenological properties. Gauge mediation remains instead a viable mechanism only in models where supersymmetry is restored in the global limit, as for example in no-scale supergravity.

The first record of dinosaur track from Hubei Province, Central China

ABSTRACT A newly discovered dinosaur tracksite in the Middle Jurassic Xietan Formation of the Zigui Basin, is the first reported from Hubei Province, China. Access to the site is difficult due to the steep inclination (~60°) of the track-bearing beds. The tracks are poorly preserved and occur in a fragmented mudstone substrate. However, it is possible to identify a sauropod trackway and isolated tridactyl (theropod) tracks, suggesting a saurischian dominated ichnofauna. The preserved sauropod trackway falls into the range of a typical wide gauge sequence and, together with the overall shape of the imprints and low heteropody, points to the ichnogenus Brontopodus. The tracks are of relatively small size and can possibly be attributed to juveniles of a large species or, alternatively, to adults of a small species of eusauropods. The tridactyl tracks are incomplete and cannot be assigned to a distinct ichnotaxon with certainty.

Interpretation of temperature transient data from coupled reservoir and wellbore model for single phase fluids

This paper presents a non-isothermal, transient coupled reservoir/wellbore model that accounts for the Joule-Thomson (J-T), isentropic expansion, conduction and convection effects for predicting the transient temperature behavior and computing the wellbore temperature at different gauge depths. In this study, single phase fluid flow of oil or geothermal brine from a fully penetrating vertical or inclined well in an infinite-acting homogeneous single layer reservoir is modeled. The coupled simulator solves mass, momentum and energy conservation equations simultaneously for both reservoir and wellbore. We improve solutions by the functional iteration procedure that updates fluid properties based on available correlations as a function of pressure and temperature at a given time step. A comparison of the developed model with a commercial simulator is provided. To understand and identify diagnostic characteristics of temperature transients at gauge locations at the sandface and above the sandface that may arise during a well test, we examine the sensitivity of the model parameters appearing in the coupled non-isothermal reservoir/wellbore model through a synthetically generated test data sets and history matched field application. The drawdown and buildup sandface transient temperature data are obtained from the coupled model and used to interpret and analyze temperature transients. In addition to the J-T coefficient of fluid, history matching transient temperature data provides estimates for the skin zone radius and permeability when analyzed jointly with the conventional pressure test analysis (PTA). An investigation on the effect of gauge location on temperature data shows that the early-time response is influenced by the wellbore phenomena while the J-T effects are clearly identified at later times at typical gauge locations up to 100 m above the top of the producing horizon. Logarithmic derivative of temperature transients are found as a useful diagnostic tool to differentiate the wellbore phenomena from the reservoir response. It is also shown that the temperature transient is more reflective of the properties of the near wellbore region (e.g., skin zone) than the pressure transient. For this reason, analyzing temperature transients together with the pressure transients could add more value to the analysis to better examine near wellbore characteristics. • A fully implicit transient single phase coupled wellbore/reservoir non-isothermal simulator is presented. • New diagnostic plots for temperature transient analysis are provided. • For typical gauge locations (usually up to 100 m above the producing horizon), reservoir response is acquired through drawdown wellbore temperature data. • An effective well radius is introduced for history matching due to the placement of many tools in wellbore during temperature transient analysis. • Reservoir and skin zone parameters are estimated reliably by history matching pressure and temperature field data together.

Catalytic recombination assessment on carbon in dissociated shock tube flow

Owing to its superior chemical stability at high temperatures, carbon is attractive as a candidate for ablation thermal protection system (TPS) materials for hypersonic re-entry vehicles. The catalytic recombination behavior is crucial to the ablation process during atmospheric entry because it provokes considerable heat flux at the surface. In the present study, catalytic efficiency values for oxygen and nitrogen recombination on carbon material have been determined by reflected shock experiments that can replicate the flow behavior of a hypersonic stagnation-point blunt body. Dissociated oxygen and nitrogen atoms were adequately produced adjacent to the shock tube endwall. Typical thin-film gauges coated with carbon are used for the stagnation heat-transfer measurements at the endwall. Before and after the tests, the properties of carbon were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Surface heat-transfer data were analyzed with catalytic heat-transfer theories. The role of recombination efficiency on the species mass fraction is also investigated by solving the governing equation for species conservation. The recombination efficiencies of carbon are found to be 0.0023 and 0.00075 for oxygen and nitrogen, respectively. It has been shown that the carbon surface is more catalytically active towards oxygen atoms than nitrogen atoms.

A generalization of intrinsic geometry and its application to Hilbert's 6th problem

The first main work of this paper is to generalize intrinsic geometry. (1) Riemannian manifold is generalized to geometrical manifold. (2) The expression of Erlangen program is improved, and the concept of intrinsic geometry is generalized, so that Riemannian intrinsic geometry which is based on the first fundamental form becomes a subgeometry of the generalized intrinsic geometry. The Riemannian geometry is thereby incorporated into the geometrical framework of improved Erlangen program. (3) The important concept of simple connection is discovered, which reflects more intrinsic properties of manifold than Levi-Civita connection. The second main work of this paper is to apply the generalized intrinsic geometry to Hilbert's 6th problem at the most basic level. (1) It starts from an axiom and makes key principles, postulates and artificially introduced equations of fundamental physics all turned into theorems which automatically hold in intrinsic geometrical theory. (2) Intrinsic geometry makes gravitational field and gauge field unified essentially. Intrinsic geometry of external space describes gravitational field, and intrinsic geometry of internal space describes typical gauge field. They are unified into intrinsic geometry. (3) Intrinsic geometry makes gravitational theory and quantum mechanics have the same view of time and space and unified description of evolution.

A generalization of intrinsic geometry and a new framework for the unification of fundamental physics

First, we show a generalization of the intrinsic differential geometry, hence the Riemannian geometry becomes its subgeometry. In such a new geometry, there exists a new connection, which reflects some more intrinsic properties of manifold than the Levi-Civita connection. These properties are closely related to gauge fields and elementary particles. Then, we apply such a generalized intrinsic geometry to establishing a new framework for the unification of fundamental physics. (1) Principles, postulates and artificially introduced equations of fundamental physics are turned into theorems based on a unique fundamental axiom, hence they obtain a common origination at a deeper level. (2) It is proposed that the time should be regarded as the total metric with respect to all internal and external spacial dimensions, and the actual evolution should be regarded as a gradient direction field, and moreover the quantum theory should be regarded as a theory of distribution of gradient directions. The above ideas make gravitational theory and quantum theory become coordinated, so they have the same view of time and space and a unified description of evolution. (3) The generalized intrinsic geometry makes the gravitational field and the gauge field unified both in form and in connotation. The intrinsic geometry of external space describes the gravitational field, and the intrinsic geometry of internal space describes the typical gauge field. They are unified into the same coordinate representation. (4) The generalized intrinsic geometry makes the gauge field and the elementary particle field originate from the same geometric construction at a deeper level. Many postulates of the Standard Model are turned into theorems in the new framework. Moreover, there are some reasonable properties beyond the Standard Model.

Non-perturbative determination of improvement coefficients b_mathrm{m} and b_mathrm{A}-b_mathrm{P} and normalisation factor Z_mathrm{m}Z_mathrm{P}/Z_mathrm{A} with N_mathrm{f}= 3 Wilson fermions

We determine non-perturbatively the normalisation parameter Z_mathrm{m}Z_mathrm{P}/Z_mathrm{A} as well as the Symanzik coefficients b_mathrm{m} and b_mathrm{A}-b_mathrm{P}, required in mathrm{O}(a) improved quark mass renormalisation with Wilson fermions. The strategy underlying their computation involves simulations in N_mathrm{f}=3 QCD with mathrm{O}(a) improved massless sea and non-degenerate valence quarks in the finite-volume Schrödinger functional scheme. Our results, which cover the typical gauge coupling range of large-volume N_mathrm{f}=2+1 QCD simulations with Wilson fermions at lattice spacings below 0.1,mathrm{fm}, are of particular use for the non-perturbative calculation of mathrm{O}(a) improved renormalised quark masses.

Calibration of a torque measuring device using an electromagnetic force torque standard machine

To realize a microtorque standard, we have been investigating the principle of torque generation with an electromagnetic force by referring to the Kibble balance method used for the redefinition of the kilogram in the International System of Units (SI). In a previous study, we developed an electromagnetic force torque standard machine (EMTSM) to create precise torque using the Kibble balance method and realize an SI-traceable, non-gravity-based torque standard. To assure the SI traceability of torque standards used in Japanese industry, it is necessary to apply the calibration procedure for torque measuring devices (TMDs) described in the Japan Measuring Instruments Federation guideline JMIF-015 when calibrating TMDs with torque standard machines (TSMs). In this study, we developed a calibration procedure for TMDs using the EMTSM with calibration procedures based on JMIF-015. In addition, we introduced a highly accurate programmable voltage/current source to expand the calibration range of the EMTSM to 0.27 μN∙m to 100 mN∙m. The relative expanded uncertainty Wtsm_e of the torque realized by the EMTSM was evaluated to be 1.7 × 10−3, with a coverage factor k of 2 over this torque range. The calibration results for a low-capacity TMD using the EMTSM with calibration procedures based on JMIF-015 were equivalent to those of a typical strain gauge torque transducer calibrated using a deadweight torque standard machine.

Thick branes in extra dimensions and suppressed dark couplings

The nature of dark matter (DM) and how it may interact with the various fields of the Standard Model (SM) remains a mystery. In this paper we show that the interaction between new light dark matter mediators and the SM particles can be naturally suppressed if one employs a single, flat extra dimension (ED). In this setup, the SM fields are localized in a finite width ‘fat’ brane, similar to models of Universal Extra Dimensions (UED), while DM, in turn, is confined to a thin brane at the opposite end of the ED interval. Including brane localized kinetic terms on the fat brane for the mediator fields, the resulting coupling between the SM and these light mediators can be several orders of magnitude smaller than the corresponding ones between the mediators and DM which we assume to be a typical gauge coupling. We investigate the implications of this scenario for both vector (i.e, dark photon, DP) and scalar mediator fields in the 5-D bulk. In this setup kinetic mixing, which is usually employed to suppress light mediator couplings, is not required. Here we assume that the SM particles couple to the DP via their B − L charges while the DP couples to the DM via a dark charge. Both the vector DP couplings and the corresponding Higgs portal couplings with the SM are shown to be natural small in magnitude with a size dependent on ratio of the 5-D compactification radius, R−1 ∼ 0.1-1 GeV, and the SM brane thickness, L−1 ∼ 2-10 TeV, a range chosen to avoid LHC and other experimental constraints. In this framework one can obtain the observed value of the DM relic abundance for a wide range of parameter choices, while the constrains due to direct DM detection and the invisible width of the Higgs do not impose significant challenges to the model. Finally, this mechanism can lead to distinct signatures in both present and upcoming experiments as it combines some common features of UED and DP models in a single ED setup.

Comparison of the GPM IMERG Final Precipitation Product to RADOLAN Weather Radar Data over the Topographically and Climatically Diverse Germany

Precipitation measurements provide crucial information for hydrometeorological applications. In regions where typical precipitation measurement gauges are sparse, gridded products aim to provide alternative data sources. This study examines the performance of NASA’s Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement Mission (IMERG, GPM) satellite precipitation dataset in capturing the spatio-temporal variability of weather events compared to the German weather radar dataset RADOLAN RW. Besides quantity, also timing of rainfall is of very high importance when modeling or monitoring the hydrologic cycle. Therefore, detection metrics are evaluated along with standard statistical measures to test both datasets. Using indices like “probability of detection” allows a binary evaluation showing the basic categorical accordance of the radar and satellite data. Furthermore, a pixel-by-pixel comparison is performed to assess the ability to represent the spatial variability of rainfall and precipitation quantity. All calculations are additionally carried out for seasonal subsets of the data to assess potentially different behavior due to differences in precipitation schemes. The results indicate significant differences between the datasets. Overall, GPM IMERG overestimates the quantity of precipitation compared to RADOLAN, especially in the winter season. Moreover, shortcomings in detection performance arise in this season with significant erroneously-detected, yet also missed precipitation events compared to the weather radar data. Additionally, along secondary mountain ranges and the Alps, topographically-induced precipitation is not represented in GPM data, which generally shows a lack of spatial variability in rainfall and snowfall estimates due to lower resolution.

Bulk-micromachined, SOI-based half-bridge silicon strain gauges for high pressure applications

This paper presents a new half-bridge silicon strain gauge fabricated on a silicon-on-insulator (SOI) substrate by MEMS bulk-micromachining technology. These gauges have holes etched through the wafer by deep reactive ion etching (DRIE) and a closed shape with four sides, unlike the current competitive devices with open structures. This unique design minimizes the shifting or rotation of gauge position and enhances the bonding strength during glass-frit bonding, leading to an improved sensor performance and yield, and hence, a reduction in sensor cost. The prototype half-bridge gauges were tested under strains ranging from −170 to 170 and were shown to have a linear output with a typical gauge factor of about 112 and an average hysteresis of 0.0192% FS. In addition, the full bridge output for 0–50 bar pressure shows a typical sensitivity of about 0.345 mV/V/bar, a maximum thermal zero shift of −7.33% FS, and a thermal sensitivity shift of −0.17% FS/°C.

Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration.

Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more.

Three-Dimensional Graphene Foam Induces Multifunctionality in Epoxy Nanocomposites by Simultaneous Improvement in Mechanical, Thermal, and Electrical Properties.

Three-dimensional (3D) macroporous graphene foam based multifunctional epoxy composites are developed in this study. Facile dip-coating and mold-casting techniques are employed to engineer microstructures with tailorable thermal, mechanical, and electrical properties. These processing techniques allow capillarity-induced equilibrium filling of graphene foam branches, creating epoxy/graphene interfaces with minimal separation. Addition of 2 wt % graphene foam enhances the glass transition temperature of epoxy from 106 to 162 °C, improving the thermal stability of the polymer composite. Graphene foam aids in load-bearing, increasing the ultimate tensile strength by 12% by merely 0.13 wt % graphene foam in an epoxy matrix. Digital image correlation (DIC) analysis revealed that the graphene foam cells restrict and confine the deformation of the polymer matrix, thereby enhancing the load-bearing capability of the composite. Addition of 0.6 wt % graphene foam also enhances the flexural strength of the pure epoxy by 10%. A 3D network of graphene branches is found to suppress and deflect the cracks, arresting mechanical failure. Dynamic mechanical analysis (DMA) of the composites demonstrated their vibration damping capability, as the loss tangent (tan δ) jumps from 0.1 for the pure epoxy to 0.24 for ∼2 wt % graphene foam-epoxy composite. Graphene foam branches also provide seamless pathways for electron transfer, which induces electrical conductivity exceeding 450 S/m in an otherwise insulator epoxy matrix. The epoxy-graphene foam composite exhibits a gauge factor as high as 4.1, which is twice the typical gauge factor for the most common metals. Simultaneous improvement in thermal, mechanical, and electrical properties of epoxy due to 3D graphene foam makes epoxy-graphene foam composite a promising lightweight and multifunctional material for aiding load-bearing, electrical transport, and motion sensing in aerospace, automotive, robotics, and smart device structures.

A fabrication process to make CNT/EP composite strain sensors

Carbon nanotube (CNT)/epoxy resin (EP) conductive composite can be obtained by solidifying the mixture of CNT and EP at specific temperature. The conductivity of the CNT/EP composite rises as the CNT content increases. It has been proven that the electrical resistance of a CNT/EP film varies when it experiences tension or compression. Therefore, the current research focuses on the design of strain sensors, based on the piezoresistivity of CNT/EP composite. In this article, an efficient method used to fabricate CNT/EP sensors is introduced in detail. One main novelty of the present method is that it provides an easy process to install metal electrodes for each piece of CNT/EP film. Another importance of the method is that it tackles the obstacles on the way to bulk production. A cantilever beam system was used to test the sensors fabricated through the self-developed process. The experimental results show that the sensors have consistent properties, and their gauge factors are much higher than that of typical foil strain gauges.

Electrical conductivity and mechanical performance of multiwalled CNT‐filled polyvinyl chloride composites subjected to tensile load

ABSTRACTThis article reports a study on the strain‐sensitive conductivity (tensoresistivity) and mechanical properties of polyvinyl chloride/multiwalled carbon nanotube (PVC/MWCNT) composites subjected to tensile loading at different strain rates for potential use in sensor‐enabled geosynthetics and other applications involving electrically conductive polymer composites. Results indicate that adding 0.5 wt % MWCNT to the composite results in 57% reduction in its ultimate (failure) strain and a fivefold increase in its tensile modulus while leaving its ultimate strength almost unchanged. Laser scanning confocal microscopy is used to investigate the microscopic failure mechanism of the composite and how it contributes to the strain‐sensitive conductivity of the composites. It is observed that tensile fractures are initiated from inside the largest bundles between 18% and 36% strain and continue through further fractal‐like fracturing in smaller bundles. Gauge factors (e.g., 3.17) comparable to or exceeding those of typical strain gauges are obtained for the composite, indicating its strong potential for structural performance monitoring and damage detection applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43665.

Air Gauge Characteristics Linearity Improvement

This paper discusses calibration uncertainty and linearity issues of the typical back-pressure air gauge. In this sort of air gauge, the correlation between the measured dimension (represented by the slot width) and the air pressure in the measuring chamber is used in a proportional range. However, when high linearity is required (e.g., nonlinearity less than 1%), the measuring range should be shortened. In the proposed method, based on knowledge of the static characteristics of air gauges, the measuring range is kept unchanged but the nonlinearity is decreased. The static characteristics may be separated into two sections, each of them approximated with a different linear function. As a result, the nonlinearity is reduced from 5% down to 1% and even below.

Finite Element Modeling of Effect of Adhesive Layer and Carrier Thickness Used for Strain Gauge Mounting

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.

Conformational dependence of the circular dichroism spectra of single amino acids from plane-waves-based density functional theory calculations.

We study the conformational dependence of circular dichroism (CD) spectra of amino acid molecules by means of an efficient ab initio DFT approach which is free from the typical gauge invariance issues arising with the use of localized basis sets and/or real-space grids. We analyze the dependence of the chiroptical spectra on the backbone dihedrals in the specific case of alanine and consider the role of side chain degrees of freedom at the examples of leucine, phenylalanine, and serine, whose side chains have different physicochemical properties. The results allow one to identify the most diagnostic regions of the CD spectra and to critically compare the conformations which match the experimental CD data with conformations extracted from the rotamer library. The inclusion of a solvation shell of explicit water molecules and its effect on the CD spectrum are analyzed at the example of alanine.