Element Mass Research Articles

Effects of lattice and mass mismatch on primary radiation damage in W-Ta and W-Mo binary alloys

The fundamental mechanisms of radiation damage in metal alloys of equiatomic composition are of great research interest due to the possibility to use them as new materials for radiation-hard environments. With W-Ta and W-Mo alloys as examples, this study investigates the effect of two factors, namely the difference in lattice parameters and the difference in masses of the constituent elements, on primary radiation damage by means of atomistic simulations. We compare the trends obtained with the available embedded atom method (EAM) interatomic potential and the tabulated Gaussian approximation potential (tabGAP). We observe a similar trend in the number of surviving defects as a function of alloy composition in W-Mo for both potentials, while the absolute numbers are fairly different. The tabGAP predicts higher resistance to irradiation, i.e. fewer surviving defects after the cascades. On the contrary, the trends of the dependence of surviving defects on alloy composition in W-Ta alloys are very different in the two potentials. We explain this difference by analyzing the threshold displacement energies (TDE) and melting temperatures in these alloys. The mass difference in W-Mo alloys results in Mo atoms with higher TDE in W-Mo alloys. The effect of the lattice parameter mismatch in W-Ta alloys is visible in the change of the number of surviving defects with increase of the W content in W-Ta alloys.

The effect of the chelated form of trace elements in diet on weight gain, production traits, egg specific gravity, immune system, blood parameters, liver enzymes, and progesterone hormone in Ross 308 broiler breeder chickens

This experiment was conducted in order to investigate the effect of the chelated form of trace elements in diet on the production traits, immunity, and blood parameters of Ross 308 broiler breeder chickens. Treatments included Treatment 1 (Negative control): Mn, Se, Cu, Fe and Zn provided as non-chelated form; Treatment 2 (Positive control): Mn, Se, Cu, Fe and Zn provided as chelated form; Treatment 3: Mn, Se, Cu, Fe and Zn provided as 50% chelated form and 50% non-chelated form; Treatment 4: Zn provided as chelated form; Treatment 5: Cu provided as chelated form; Treatment 6: Fe provided as chelated form; Treatment 7: Mn provided as chelated form; Treatment 8: Se provided as chelated form. The results showed that over the entire production period egg production and egg mass were affected by the experimental treatments (p < 0.05) and that the highest levels were observed in treatments 2 and 3. The chelated form of trace elements had a significant effect, increasing the number of settable eggs and decreasing the unsettable eggs over the entire production period (p < 0.05). Average egg weight over the entire period was not significantly changed (p > 0.05). The highest percentage of 2-yolk, thin shell, broken and small eggs was observed in 61st week of age significantly (p < 0.05). The experimental treatments had a significant effect on the immunity and the antibody titre against Newcastle disease showed a significant increase in treatments 2 and 8 (p < 0.05). The concentration of glucose, triglyceride, progesterone, AST and ALT were affected by the experimental treatments (p < 0.05). In conclusion, the use of a basic diet containing Zn, Fe, Cu, Se and Mn in the chelated form or the use of a basic diet containing mineral elements of Zn, Fe, Cu, Se and Mn with 50% non-chelated form and 50% in the chelated form improves the performance of production traits, immunity and blood parameters of Ross 308 broiler breeder chickens. Highlights Chelated form of trace elements in the diet led to improvement in productive traits, immune response and blood parameters compared to the mineral form Basic diet containing mineral elements of Zn, Fe, Cu, Se, and Mn, 50% in the non-chelated form and 50% in the chelated form led to a significant improvement in egg production, egg mass, egg weight and egg specific gravity Chelated form of trace elements in the diet led to a decrease in the number of abnormal eggs including double-yolk, thin shell, broken, deformed, and small eggs

An analysis of band gap characteristics of metamaterial plates with dual helix cells

Wide band gaps with the propagation of elastic waves at low-frequency are desirable for phononic crystals in many traditional and novel applications. Inspired by the natural helix, we designed a microstructure in a metamaterial plate with an antisymmetric dual helix as the basic local resonant cell. The band structure and displacement transmission curve of metamaterial plates with dual helix cells were calculated by using the finite element method at first, then the band gap characteristics with and without consideration of the mass in the center of the dual helix were compared. The results show that the band gap in the band structure and displacement transmission curves have excellent consistency. Besides, the effects of the parameters including the number of turns of the helix, the plate thickness, and the radius of the attached mass sphere on the band gaps of flexural waves for the metamaterial plate were examined for further evaluation of the potential vibration prohibition application. It is found that the lower frequency of the band gap can be significantly tuned by adding a mass element in the metamaterial plates with dual helix elements, which provides a new method to tune the width of the band gap of a metamaterial plate.

Air Quality Impacts on the Giant Panda Habitat in the Qinling Mountains: Chemical Characteristics and Sources of Elements in PM2.5

The wild giant panda habitat is inaccessible and far away from the main areas of human activity, so environmental pollutants entering the habitat are mainly the result of external migration and spread through the atmospheric advection and diffusion processes and particulate matter deposition. To research the variation, transmission route, chemical characteristics, and source of PM2.5 in the habitat of wild giant pandas, we set up a PM2.5 sampling point near the Shaanxi Foping National Nature Reserve (SFNNR), which is the area with the highest population density of wild giant pandas in the Qinling Mountains. The 12-month average concentration of PM2.5 was 11.3 ± 7.9 μg/m3 from July 2021 to June 2022, and the 12-month average concentration did not exceed the limit value set in the standard. In the results of our analysis of element concentrations, As and Pb were much lower than the limit standard. Si, S, P, and Cl accounted for 99.60% of nonmetallic elements, while the proportion of the six metallic elements, Na, Mg, Al, K, Ca, and Fe, was 96.27%. According to the analysis results of enrichment factor (EF) and pollutant emission sources, there were four sources for the total elements in PM2.5, which were mainly distributed in the areas around the reserve. These included dust, coal combustion, biomass burning, and traffic-related emissions, which contributed 55.10%, 24.78%, 11.91%, and 8.22% of the total element mass in PM2.5, respectively. Additionally, Pb, Cu, Zn, As, Sc, Co, Ga, Mg, and, especially, Se were severely affected by human activities (coal burning, biomass burning, and traffic-related emissions). In the villages and towns around the wild giant panda habitat, the majority of energy for cooking and heating comes from coal and biomass burning, and older vehicles with high emissions are used more frequently. Therefore, to better protect the health of and reduce the impact of environmental pollution on wild giant pandas, we put forward relevant recommendations, including upgrading the energy structure of towns and villages near the habitat to increase the proportion of clean energy, such as photovoltaic power generation, natural gas, etc.; decreasing the combustion of coal and biomass; encouraging the upgrading of agricultural diesel machines and older vehicles used in these areas; and setting limits on vehicle emissions in areas surrounding the habitat.

Evolution and explosions of metal-enriched supermassive stars: proton rich general relativistic instability supernovae

ABSTRACT The assembly of supermassive black holes poses a challenge primarily because of observed quasars at high redshift, but additionally because of the current lack of observations of intermediate mass black holes. One plausible scenario for creating supermassive black holes is direct collapse triggered by the merger of two gas-rich galaxies. This scenario allows the creation of supermassive stars with solar metallicity. We investigate the behaviour of metal enriched supermassive stars which collapse due to the general relativistic radial instability during hydrogen burning. These stars contain both hydrogen and metals and thus may explode due to the CNO cycle (carbon–nitrogen–oxygen) and the rp process (rapid proton capture). We perform a suite of stellar evolution simulations for a range of masses and metallicities, with and without mass-loss. We evaluate the stability of these supermassive stars by solving the pulsation equation in general relativity. When the stars becomes unstable, we perform 1D general relativistic hydrodynamical simulations coupled to a 153 isotope nuclear network with cooling from neutrino reactions, in order to determine if the stars explode. If the stars do explode, we post process the nucleosynthesis using a 514 isotope network which includes additional proton rich isotopes. These explosions are characterized by enhanced nitrogen and intermediate mass elements ($16\ge \rm {A}\ge 25$), and suppressed light elements ($8\ge \rm {A}\ge 14$), and we comment on recent observations of super-solar nitrogen in GN-z11.

Numerical Study on Asteroid Deflection by Penetrating Explosion Based on Single-Material ALE Method and FE-SPH Adaptive Method

An asteroid impact can potentially destroy life on this planet. Therefore, asteroids should be prevented from impacting the Earth to impede severe disasters. Nuclear explosions are currently the only option to prevent an incoming asteroid impact when the asteroid is large or the warning time is short. However, asteroids exist in an absolute vacuum, where the explosion energy propagation mechanism differs from that in an air environment. It is difficult to describe this process using standard numerical simulation methods. In this study, we used the single-material arbitrary Lagrangian–Eulerian (ALE) method and the finite element-smoothed particle hydrodynamics (FE-SPH) adaptive method to simulate the process of deflecting hazardous asteroids using penetrating explosions. The single-material ALE method can demonstrate the expansion process of explosion products and energy coupling in absolute vacuum. The FE-SPH adaptive method can transform failed elements into SPH particles during the simulation, avoiding system mass loss, energy loss, and element distortion. We analyzed the shock initiation and explosion damage process and obtained an effective simulation of the damage evolution, stress propagation, and fragment distribution of the asteroid. In addition, we decoupled the penetrating explosion into two processes: kinetic impact and static explosion at the impact crater. The corresponding asteroid damage modes, velocity changes, and fragmentation degrees were simulated and compared. Finally, the high efficiency of the nuclear explosion was confirmed by comparing the contribution rates of the kinetic impact and nuclear explosion in the penetrating explosion scheme.

The Earth's rotational modes revisited

In the conventional treatment of the Earth's rotational dynamics using the Earth's angular momentum description (AMD), it is customary to assume that the velocity/displacement of a mass element in the liquid core (LC) has a displacement as well as an explicit rigid rotation component in addition to the uniform (solid-body) rotation. This makes for a very complex set of non-linear differential equations in the treatment of the dynamics of this body. In this work, I will use a simple three-layer Earth model with a rigid mantle (MT), a rigid inner core (IC), and an incompressible and homogeneous LC to show that in the alternative linearised dynamics of this body, it is redundant to assign a rigid rotation component to the motion. Next, I will use an approximation commonly used in dealing with the Earth's rotational dynamics, and further assume that the MT rotates uniformly, to show that the linearised equations yield identical analytical results to those in the literature for the periods of the inner-core wobble (ICW) and the free inner-core nutation (FICN).

Determination of the Matrix Composition of Glasses of the Ga–Ge–Te–I System by Inductively Coupled Plasma Atomic Emission Spectrometry

A procedure is developed for the high-precision determination of matrix elements of high-purity glasses of the Ga–Ge–Te–I system, containing from 5 to 15 at % Ga, from 10 to 20 at % Ge, from 69 to 75 at % Te, and from 1 to 6 at % I, using inductively coupled plasma atomic emission spectrometry. The procedure includes two stages independent of each other: determination of the ratio of the mass fractions of Ga and Te to the mass fraction of Ge (stage 1) and determination of the mass fraction of I (stage 2) in the glass sample. Based on these values, the mass and mole fractions of each matrix element of the analyzed sample were calculated. Sample preparation includes the acid dissolution (provides quantitative transfer of Ga, Ge, and Te into the solution) and alkaline opening (provides quantitative transfer of I into the solution) of samples. The accuracy of the results of analysis was confirmed by comparing the results of an analysis of model solutions and model glass samples with the calculated composition. The estimated uncertainty of the results of analysis is 0.05–0.1 at % at P = 0.95.

Effect of Geometry Precision and Load Distribution on Branch Mechanical Response

Tree risk assessment requires mechanical response studies, but simplification of the shape, material, or boundary conditions is necessary when dealing with such complex structures. To observe overall tree response, sub-structuring to several levels of detail can be used, enabled by recent developments in numerical methods and three-dimensional laser scanning (3D scan). This study aimed to determine an appropriate level of geometry and loading simplification allowed for high-order branches at the crown border, which is useful for the mechanical analysis of structured tree models. Four higher-order branches were pruned and experimentally tested by single-point loading. Beam and solid finite-element models (FEMs) were created based on measured geometric parameters and detailed 3D scans, respectively. The FEMs were used to analyze seven loading scenarios with force applied at (a) the center of gravity, (b) the top of side branches, (c) key discrete points, and (d) uniformly to the whole volume (to each finite element). Force was distributed by ratios weighted according to the mass, area, and diameter of side branches; or according to the mass of each finite element. The results showed no significant difference between the beam model and 3D scan-based model. The scenarios with finite elements’ mass-based force distribution deviated significantly from those of the other scenarios. The most simplified single-point loading caused a deviation in the deflection curve. The deviation of single-point loading in the case of the bending moment was related to force distribution ratios given by the branches architecture. Therefore, such loading simplification is not considered always appropriate. Consistency between the bending moment and branch deflection provided a representative mechanical response, recommended for further modeling of trees by sub-structuring.

Textural and chemical evolution during dedolomitization: A case study of the Benassal Formation, Maestrat Basin, Spain

The process of dedolomitization (dolomite calcitization) has been the subject of several studies, but the mechanisms that control it are still not fully understood. Dedolomitization, i.e. the replacement of dolomite by calcite, is an important diagenetic process that affects dolostones, in certain cases decreasing the local porosity and altering the rock mechanical properties, reservoir quality and fluid flow pathways. In this contribution we report the petrographic and geochemical evidence of the progressive dedolomitization and its impact on the Lower Cretaceous dolostones of the Benicàssim area (Maestrat Basin, Spain) that host Mississippi Valley Type (MVT) ore deposits. Textural observations and geochemical data suggest that replacement was induced by the interface coupled dissolution-precipitation mechanism. Moreover, quantitative chemical content measurements with mass balance calculations show that dedolomitization caused a ∼5% gain of mass during the reaction, associated with 5 vol% of solid volume increase. The lack of microfracture development suggests that the compensation of such volume increase is achieved by microporosity being filled during calcite precipitation. Considering the meteoric origin of the dedolomitizing fluids, the mass balance calculation allows estimating the element mass transfer during the reaction. The fact that the fluid was enriched in Zn supports that the fluid was acidic, and likely percolated through the local MVT deposits. Calculation of the required volume of the reactive fluid (102–104 m3/m3 dolostone) also shows that thermodynamic calculations overestimate the volume of fluid. This study shows the importance of quantifying mass transfer in diagenetic conditions to better understand metasomatic processes and constrain the fluid pathway in the basin history. As a societal impact, this diagenetic process releases ∼11% of the carbon mass but seems to preserve all rare earth elements.

Particle Swamp Optimized -Physics-Informed Deep Learning for Heterogeneous Oil and Gas Underground Reservoir Pressure Management.

In recent years, Particle Swarm Optimization (PSO) has been integrated with machine learning algorithms, such as deep learning, to create powerful hybrid methods that can tackle complex optimization problems more effectively. In the domain of oil and gas reservoir management, underground pressure management is crucial to maximize the yield and efficiency of the reservoir. However, the heterogeneity of the reservoir, along with uncertainties in its properties, makes pressure management a complex and challenging task. To address this issue, researchers have proposed Physics-Informed Deep Learning (PIDL) techniques that incorporate domain-specific knowledge, such as the governing physical equations, into the deep learning framework. Particle Swarm Optimized-Physics-Informed Deep Learning (PSO-PIDL) is a novel hybrid approach that combines PSO with PIDL to optimize the pressure management of heterogeneous oil and gas underground reservoirs. In this approach, the PSO algorithm is used to find the optimal solution for the PIDL-based model that incorporates the governing physical equations of the reservoir. PSO-PIDL can effectively handle the uncertainties and heterogeneity of the reservoir, while also incorporating the physical constraints of the problem. Overall, PSO-PIDL is a promising approach for optimizing the pressure management of oil and gas reservoirs. It can help reduce the operational costs and improve the efficiency of the reservoir, while also ensuring the sustainable use of natural resources. Keywords: Physics-Informed Deep Learning, Particle Swarm Optimization, Bidirectional Long-Short-Term-Memory, Heterogeneous Reservoir, DuPont Finite Element Heat and Mass Transfer Code

Particle Swamp Optimized -Physics-Informed Deep Learning for Heterogeneous Oil and Gas Underground Reservoir Pressure Management.

In recent years, Particle Swarm Optimization (PSO) has been integrated with machine learning algorithms, such as deep learning, to create powerful hybrid methods that can tackle complex optimization problems more effectively. In the domain of oil and gas reservoir management, underground pressure management is crucial to maximize the yield and efficiency of the reservoir. However, the heterogeneity of the reservoir, along with uncertainties in its properties, makes pressure management a complex and challenging task. To address this issue, researchers have proposed Physics-Informed Deep Learning (PIDL) techniques that incorporate domain-specific knowledge, such as the governing physical equations, into the deep learning framework. Particle Swarm Optimized-Physics-Informed Deep Learning (PSO-PIDL) is a novel hybrid approach that combines PSO with PIDL to optimize the pressure management of heterogeneous oil and gas underground reservoirs. In this approach, the PSO algorithm is used to find the optimal solution for the PIDL-based model that incorporates the governing physical equations of the reservoir. PSO-PIDL can effectively handle the uncertainties and heterogeneity of the reservoir, while also incorporating the physical constraints of the problem. Overall, PSO-PIDL is a promising approach for optimizing the pressure management of oil and gas reservoirs. It can help reduce the operational costs and improve the efficiency of the reservoir, while also ensuring the sustainable use of natural resources. Keywords: Physics-Informed Deep Learning, Particle Swarm Optimization, Bidirectional Long-Short-Term-Memory, Heterogeneous Reservoir, DuPont Finite Element Heat and Mass Transfer Code

A new method for the timber tracing toolbox: applying multi-element analysis to determine wood origin

To effectively reduce illegal timber trade, law enforcers need forensic methods to independently verify claims of wood origin. Multi-element analysis of traded plant material has the potential to be used to trace the origin of commodities, but for timber it has not been tested at relevant large scales. Here we put this method to the test, by evaluating its tracing accuracy for three economically important tropical timbers: Azobé and Tali in Central Africa (22 sites) and Red Meranti on Borneo (9 sites). Wood samples from 991 trees were measured using Inductively Coupled Plasma Mass Spectrometry and element concentrations were analysed to chemically group similar sites (clustering) and assess accuracy of tracing samples to their origin (Random Forest models). For all three timbers, we found distinct spatial differences in chemical composition. In Central Africa, tracing accuracy was 86%–98% for regional clusters of chemically similar sites, with accuracy depending on the tracing question. These clusters were 50–800 km apart and tracing accuracy was highest when combining the two timbers. Tracing accuracy of Red Meranti on Borneo was 88% at the site level. This high accuracy at a small scale may be related to the short distances at which differences in soil type occur on Borneo. A blind sample analysis of 46 African timber samples correctly identified the origin of 70%–72% of the samples, but failed to exclude 70% of the samples obtained from different species or outside the study area. Overall, these results illustrate a high potential for multi-element analysis to be developed into a timber tracing tool which can identify origin for multiple species and can do so at a within-country scale. To reach this potential, reference databases need to cover wider geographic areas and represent more timbers.

New Compositional and Structural Constraints on the Smithsonian Microanalytical Reference Materials: Amphiboles from Kakanui and Arenal

The amphiboles from Kakanui and Arenal are two natural minerals that have been used worldwide as microanalytical reference materials, but their compositions and crystal structures are still poorly constrained. In this paper, we report new data on H2O and trace element mass fractions and single‐crystal structural refinement of these two amphiboles. H2O mass fractions of the Kakanui and Arenal amphiboles determined via Karl‐Fischer titration are 0.92 ± 0.18 (2s) and 1.56 ± 0.22% m/m (2s), respectively; these values estimated based on crystal‐structure refinement are 0.86 and 1.46% m/m, respectively. Trace element mass fractions measured via LA‐ICP‐MS in two laboratories are in good agreement, and spots from five fragments for both Kakanui and Arenal amphiboles are generally consistent within reproducibility precision (2s). Our measurements indicate a better homogeneity for the amphiboles from Kakanui than that from Arenal. According to the latest scheme for amphibole classification and nomenclature (Hawthorne et al. 2012), the sample from Arenal is a (partially dehydrogenated) pargasite, and that from Kakanui is a kaersutite. The significant amount of oxo‐component and that CTi4+ content is strongly ordered at the M(1) site for both amphiboles indicate crystallisation under high fO2 conditions.

СОВЕРШЕНСТВОВАНИЕ МЕТОДИКИ ОЦЕНКИ ВИБРАЦИОННОЙ НАГРУЖЕННОСТИ КУЗОВА ПАССАЖИРСКОГО ВАГОНА

The analysis of domestic and foreign studies in the field of evaluating the dynamic strain of passenger car bodies allowed us to find out that most of the methods are based on the evaluation of the vibration strain. An improved method is proposed to consider to evaluate the vibration strain of the car. As a method for determining the body's structural properties, a mathematical modeling method is proposed. On the basis of this method, a finite element model of the body is developed, which natural frequencies and forms of vibrations are calculated by Lanczos method. The results obtained by finite element model are compared with the data obtained during tests conducted by the Testing Center TIV. The discrepancy between the calculation and the experiment is 11.85%, which indicates the adequacy of the created finite element model. To define the dynamic load of the body the developed finite element model was reduced to four variants, each of which is transformed into a spatial hybrid dynamic model. The results obtained during the calculation are compared with the values of the running tests of the car. The analysis of the data shows that the fourth variant of the finite element model of the passenger car body, which takes into account the real distribution of the mass of the internal equipment elements and the interior has values more approximate to the data obtained during running tests. Based on this, it can be concluded that this option is most suitable for calculating the stiffness characteristics of the passenger car body.

On the incorporation of conservation laws in machine learning tabulation of kinetics for reacting flow simulation

Tabulation of chemical mechanisms with artificial neural networks (ANNs) offers significant speed benefits when computing the real-time integration of reaction source terms in turbulent reacting flow simulations. In such approaches, the ANNs should be physically consistent with the reaction mechanism by conserving mass and chemical elements, as well as obey the bounds of species mass fractions. In the present paper, a method is developed for satisfying these constraints to machine precision. The method can be readily applied to any reacting system and appended to the existing ANN architectures. To satisfy the conservation laws, certain species in a reaction mechanism are selected as residual species and recalculated after ANN predictions of all of the species have been made. Predicted species mass fractions are set to be bounded. While the residual species mass fractions are not guaranteed to be non-negative, it is shown that negative predictions can be avoided in almost all cases and easily rectified if necessary. The ANN method with conservation is applied to one-dimensional laminar premixed flame simulations, and comparisons are made with simulations performed with direct integration (DI) of chemical kinetics. The ANNs with conservation are shown to satisfy the conservation laws for every reacting point to machine precision and, furthermore, to provide results in better agreement with DI than ANNs without conservation. It is, thus, shown that the proposed method reduces accumulation of errors and positively impacts the overall accuracy of the ANN prediction at negligible additional computational cost.

Effect of Zn on Corrosion Resistance of 5083 Alloys

The effect of addition of 1.5% -5% Zn (mass fraction) on the corrosion performance of alloy 5083 was studied. Homogenization and post-rolling of the alloy were analysed by immersion and electrochemical tests in 3.5% NaCl aqueous solution. The result is as follows: the rate of weight loss increases at the same soak time with the increasing of Zn element mass fraction. The weight loss rate of the alloy rolled is obviously higher than that of homogenized alloy at the same immersion time and Zn content mass fraction. The homogenization of the same components and the self corrosion potential and self corrosion current of rolled alloy at different soaking time are not very obvious. The effect of immersion time on the corrosion resistance of the alloy is not obvious. With the increasing of the Zn element mass fraction, the self-corrosion potential of the homogenized and rolled alloy decreases overall, so the corrosion resistance of the alloy decreases with the increasing of Zn element mass fraction. The homogeneously treated alloy has a higher self-corrosion potential than the alloy rolled, therefore, the alloy rolled has lower corrosion resistance than the homogenized alloy.

Authentication of beef cuts by multielement and machine learning approaches

BackgroundBrazil has consolidated a relevant position in the world market, being the largest exporter and second producer of beef. Genetics, feeding system, geographic origin and climate influence the multielement profile of beef. The feasibility of combining classification algorithms with major and trace elements was evaluated as a tool for authentication of beef cuts. MethodsAnimals of Angus, Nelore and Wagyu crossbreeds, raised in a vertically integrated system, were sampled at the slaughterhouse for chuck steak, rump cap and sirloin steak. Supervised learning algorithms i.e. Classification and Regression Tree (CART), Multilayer Perceptron (MLP), Naïve Bayes (NB), Random Forest (RF) and Sequential Minimal Optimization (SMO) were used to build classification models based on the multielement profile of beef determined by neutron activation analysis. ResultsBr, Co, Cs, Fe, K, Na, Rb, Se and Zn were determined in the beef samples. The classification accuracy values obtained for the beef cuts were 96% (MLP), 95% (SMO), 91% (RF), 86% (NB) and 70% (CART). ConclusionThe Multilayer Perceptron algorithm provided the best classification performance towards authentication of beef cuts on basis of major and trace element mass fractions.

Apatite Reference Materials for SIMS Microanalysis of Isotopes and Trace Elements

Twelve apatite samples have been tested as secondary ion mass spectrometry (SIMS) reference materials. Laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) analysis shows that the SLAP, NUAN and GR40 apatite gems are internally homogeneous, with most trace element mass fractions having 2 standard deviations (2s) ≤ 2.0%. BR2, BR5, OL2, AFG2 and AFB1, which have U &gt; 63 μg g‐1, 206Pb/204Pb &gt; 283, and homogeneous SIMS U‐Pb data, have respective isotope dilution thermal ionisation mass spectrometry (ID‐TIMS) ages of 2053.83 ± 0.21 Ma, 2040.34 ± 0.09 Ma, 868.87 ± 0.25 Ma, 478.71 ± 0.22 Ma and 473.25 ± 0.09 Ma. Minor U‐Pb heterogeneity exists and accurate SIMS results require correction with the 3D Concordia‐constrained common Pb composition. Among the studied samples, AFG2 and BR5 are the most homogeneous U‐Pb reference materials. The SIMS sulfur isotopic compositions of eight of the apatites shows they are homogeneous, with 2s for both 103δ34S and 103δ33S &lt; 0.55‰. One apatite, BR96, has Δ33S = ‐0.36 ± 0.2‰. The apatite samples have ID‐TIMS 87Sr/86Sr between 0.704214 ± 0.000030 and 0.723134 ± 0.000035.

Vibration Analysis of the Base Structure Supporting a Centrifuge–Motor Assembly in a Petroleum Oil Refinery

A structure carrying a centrifuge and motor in a petroleum oil refinery has been vibrating above the alarm limit of vibration. This has been a recurring problem. The maintenance work undertaken at regular intervals on the basis of time waveform and spectrum analysis could provide only a temporary solution. To investigate the causes of vibration above the acceptable limits, pre-stressed modal analysis of the structure was undertaken by using Finite Element Analysis software ANSYS™ and natural frequencies and mode shapes were extracted. Pre-stressing was done by considering the self-weight of the structure, centrifuge and motor. The structure was analyzed using a combination of beam elements, shell elements and mass elements. The operating deflection shape (ODS) technique which helps to observe the deflection pattern of structure in real time at operating or other frequencies from the measured vibration data was employed to validate the analytical results. ME’scopeVES™ software employing the ODS technique was used in this work. Analytical results obtained from ANSYS™ software are compared well with the ODS test results. The analysis of analytical and experimental results has revealed that the structure was operating in the resonance band.