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Human walking is an activity which generates impulsive responses on floors systems with fundamental frequency higher than 10 Hz. In the literature, there are procedures based on extensive polynomial functions to calculate impulsive responses on floor systems under human walking. However, the prediction of this type of human activity in the development of analytical procedures is still complex. Because of that, it is necessary to provide alternatives of human walking simulation and dynamic response analysis of the floor system. Considering this, a practical procedure based on the use of a simple harmonic function is proposed to calculate the impulsive response of the floor system, which is validated with a numerical-experimental study consisting of a concrete slab supported on beams subjected to a person's walking. According to the obtained results, it is demonstrated that the proposed procedure provides reasonably approximate results. [ABSTRACT FROM AUTHOR]

The modern project environment is characterized by high complexity, uncertainty, speed and depth of changes that affect the project during its life cycle. However, the project’s change management processes do not take into account the need to implement analytical procedures for dynamic processing of multimodal data arrays. The purpose of the study is to determine the content of analytical procedures for project management and substantiate the use of machine learning technologies for their effective implementation. The methodological basis was project management methods, theory of change, concepts of artificial intelligence and machine learning, as well as analytical approaches. Methods of descriptive modeling of the project management process and expert assessments of the prospects for using machine learning technologies were also used in the work. The information base was made up of scientific materials on the topic under consideration, as well as expert assessments. The results of the study allowed us to conclude that for the analysis of multimodal data, natural language processing and intellectual decision support technologies are most in demand, which can serve as the basis for new technological solutions in the field of project management.

The current manuscript critically examines the propagation of horizontally polarized shear waves on the dispersion of a highly inhomogeneous thin bonded bi-material plate when a load due to the Winkler's elastic foundation is prescribed. An analytical procedure of solution is deployed for the study; in addition to the exploitation of effective boundary conditions approach for the asymptotic examination. The overall inference of the current study is the realization of the fact that the vibrational displacements in both layers are enhanced by an increase in the inhomogeneity parameter; at the same time lessened with an increment in the foundation parameter. Moreover, a perfect approximation of the dispersion relation has been realized, with its validity extending to almost the entire low-frequency range. Lastly, the influence of the material inhomogeneity has been noted to affect fundamental mode, as against the presence of the foundation parameter which affects the first harmonic curve. More so, an increase in the two parameters narrows the chances of low-frequency propagation.

This analysis scrutinizes the hydromagnetic flow of nanofluids towards a shrinking sheet with thermal radiation. Three different fluids are examined namely Al2O3-ZnO/ kerosene hybrid nanofluid, Al2O3/ kerosene nanofluid, and ZnO/ kerosene nanofluid, where aluminum oxide (Al2O3) and zinc oxide (ZnO) are chosen as the nanomaterials with kerosene oil as the base fluid. Utilizing the similarity transformations, the coupled partial differential equations controlling the flow problem are turned into a favorable nonlinear system of ordinary differential equations which are solved analytically by employing the Least square method (LSM). Dual solutions are found in a certain range of the velocity ratio parameterλ. This leads to implementing the stability analysis to verify the realizable solution from both solutions in which one solution is found to be stable while the other solution is unstable. The least eigenvalues are evaluated with the help of the bvp4c function from MATLAB software. The influences of governing parameters including both base fluid and nanoparticles masses, velocity ratio parameterλ, magnetic parameterM, Prandtl numberPr, and radiation parameter R on the flow and heat transfer characteristics are demonstrated and discussed, in tabular and graphical forms.

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Featured Application: The proposed analytical method is suitable to check the stability (lateral and longitudinal) of the combination of a counterbalanced forklift truck with an interchangeable equipment and to assess if the interchangeable equipment could be safely assembled to the forklift truck. Counterbalanced forklift trucks (FLT) are frequently used in combination with interchangeable equipment in order to handle loads in different manners. The main risks which may arise after assembling interchangeable equipment to a FLT are related to the loss of stability of the assembly. Actually, the presence of interchangeable equipment and the associated payload may change in a significant way the overall centre of gravity with respect to the FLT in its basic configuration with forks. Therefore, the stability limits of the assembly, based on the same footprints on the ground of the FLT alone, are affected by the position of the overall centre of gravity. Thus, the presence of interchangeable equipment could reduce the functionality (e.g., lifting capability, lifting height, etc.) of the FLT in order to continue its stability during use. Often, interchangeable equipment is placed on the market by manufacturers other than the FLT manufacturer. In these cases, the correct and safe coupling of the interchangeable equipment with the FLT is the responsibility of the manufacturers of interchangeable equipment, including the stability risk assessment. Thus, the interchangeable equipment manufacturer should have access to the relevant information of the FLT concerning operative and structural features and its configuration as a procedure for assessing the correct and safe coupling. Otherwise, he should perform experimental stability tests for each model of FLT so that its interchangeable equipment can be fitted. Specific research activity is developed in order to define an analytical procedure to assess the stability of FLT when assembled with interchangeable equipment. Specific typologies of FLTs and interchangeable equipment have been selected in order to better characterise the case study. The analytical equations mimic the static stability tests. The results achieved have been compared to experimental data in order to optimise the procedure. The results attained by the application of the analytical procedure to all the combinations of main typologies of FLTs and the interchangeable equipment selected showed good agreement with experimental tests. [ABSTRACT FROM AUTHOR]

The current manuscript critically examines the propagation of horizontally polarized shear waves on the dispersion of a highly inhomogeneous thin bonded bi-material plate when a load due to the Winkler's elastic foundation is prescribed. An analytical procedure of solution is deployed for the study; in addition to the exploitation of effective boundary conditions approach for the asymptotic examination. The overall inference of the current study is the realization of the fact that the vibrational displacements in both layers are enhanced by an increase in the inhomogeneity parameter; at the same time lessened with an increment in the foundation parameter. Moreover, a perfect approximation of the dispersion relation has been realized, with its validity extending to almost the entire low-frequency range. Lastly, the influence of the material inhomogeneity has been noted to affect fundamental mode, as against the presence of the foundation parameter which affects the first harmonic curve. More so, an increase in the two parameters narrows the chances of low-frequency propagation. [ABSTRACT FROM AUTHOR]

This analysis scrutinizes the hydromagnetic flow of nanofluids towards a shrinking sheet with thermal radiation. Three different fluids are examined namely A l 2 O 3 - Z n O / kerosene hybrid nanofluid, A l 2 O 3 / kerosene nanofluid, and ZnO / kerosene nanofluid, where aluminum oxide (A l 2 O 3) and zinc oxide (Z n O) are chosen as the nanomaterials with kerosene oil as the base fluid. Utilizing the similarity transformations, the coupled partial differential equations controlling the flow problem are turned into a favorable nonlinear system of ordinary differential equations which are solved analytically by employing the Least square method (LSM). Dual solutions are found in a certain range of the velocity ratio parameter λ. This leads to implementing the stability analysis to verify the realizable solution from both solutions in which one solution is found to be stable while the other solution is unstable. The least eigenvalues are evaluated with the help of the bvp4c function from MATLAB software. The influences of governing parameters including both base fluid and nanoparticles masses, velocity ratio parameter λ , magnetic parameter M , Prandtl number P r , and radiation parameter R on the flow and heat transfer characteristics are demonstrated and discussed, in tabular and graphical forms. [ABSTRACT FROM AUTHOR]

Steroid hormones, such as 17β-testosterone, 11-ketotestorenone and 17β-estradiol, play an essential role not only in reproductive function but also are potential biomarkers of numerous additional functions in teleost fish. The presence of endocrine disruptor compounds in aquatic ecosystems has raised concern about their effect on hormone levels in fish target organs. Since hormones are present in very low concentrations in biological material, their determination still remains a challenge. A new analytical procedure has been developed to determine 17β-testosterone, 11-ketotestosterone and 17β-estradiol in the sea trout female and male gonads by liquid chromatography-tandem mass spectrometry (LC-MS/MS) system equipped with an ESI source operating in both positive and negative mode. Chromatographic separation of analytes was accomplished in Poroshell 120 EC-C18 (150 mm × 2.1 mm, 2.7 µm) column under isocratic elution conditions. The mobile phase consisted of acetonitrile, methanol and water (20:50:30/v/v/v) at a flow rate of 0.2 mL/min. Analytes were extracted from the gonad matrix with ethyl acetate, and co-extractives impurities were successfully removed by QuEChERS (quick, easy, cheap, effective, rugged and safe) method. The procedure was validated with good sensitivity, linearity, accuracy, and precision. Limits of quantifications were from 0.15 to 0.75 ng/g, linearity was obtained with correlation coefficient R > 0.99, accuracy was from 94.0 to 109.5%, precision expressed as RSD ranged from 1.7 to 27.2% (repeatability) and from 2.2 to 37.1% (reproducibility). Finally, the method was applied to determining 17β-testosterone, 11-ketotestosterone and 17β-estradiol in real samples of the female and male sea trout gonads, 8 and 22 samples, respectively. [ABSTRACT FROM AUTHOR]

Background and Objectives: Reliable methods are necessary to analyze polychlorinated biphenyls in baby foods, dietary supplements commonly used for children. Nowadays, contamination of food products, mostly derived from agricultural sources, with polychlorinated biphenyls seems inevitable. Of these, cereal-based baby foods are highly important due to the long-term side effects of polychlorinated biphenyls in babies. Materials and Methods: In this study, a validated method was developed for the assessment of 12 polychlorinated biphenyls in baby foods based on the solid-phase extraction column sample preparation and gas chromatography-electron capture detectore using PCB 77 and PCB 189 as internal standards. Validation of the method was assessed by the calculated and achieved parameters for linearity, mean recovery, precision, limit of quantification and limit of detection. Results: Recoveries at three levels of 0.5, 1 and 2 μg/kg in repeatability and reproducibility studies were in ranges of 78.89-98.32 and 77.28-98.45%, respectively. Linearity was presented as R2 value from 0.9980 to 0.9999, indicating good correlations between the concentrations and peak areas. Limit of quantification and limit of detection were 0.5 and 0.16 (ng/g). Analysis of 30 samples showed that six polychlorinated biphenyls were available in 7% of the samples; of which, 93% were not contaminated with polychlorinated biphenyls. None of the samples contaminated with polychlorinated biphenyls included contamination higher than the maximum residue limit. Conclusions: Validated methodology was used in polychlorinated biphenyl analysis in various trademarks of cerealbased baby foods commercialized for the Iranian markets. Samples were screened based on the maximum residue limit by the European Union. This method is a simple method and can be carried out in a short time with high accuracy and precision. [ABSTRACT FROM AUTHOR]

In this article, exact solutions of some Laplace-type fractional boundary value problems (FBVPs) are investigated via natural decomposition method. The fractional derivatives are described within Caputo operator. The natural decomposition technique is applied for the first time to boundary value problems (BVPs) and found to be an excellent tool to solve the suggested problems. The graphical representation of the exact and derived results is presented to show the reliability of the suggested technique. The present study is mainly concerned with the approximate analytical solutions of some FBVPs. Moreover, the solution graphs have shown that the actual and approximate solutions are very closed to each other. The comparison of the proposed and variational iteration methods is done for integer-order problems. The comparison, support strong relationship between the results of the suggested techniques. The overall analysis and the results obtained have confirmed the effectiveness and the simple procedure of natural decomposition technique for obtaining the solution of BVPs.

Counterbalanced forklift trucks (FLT) are frequently used in combination with interchangeable equipment in order to handle loads in different manners. The main risks which may arise after assembling interchangeable equipment to a FLT are related to the loss of stability of the assembly. Actually, the presence of interchangeable equipment and the associated payload may change in a significant way the overall centre of gravity with respect to the FLT in its basic configuration with forks. Therefore, the stability limits of the assembly, based on the same footprints on the ground of the FLT alone, are affected by the position of the overall centre of gravity. Thus, the presence of interchangeable equipment could reduce the functionality (e.g., lifting capability, lifting height, etc.) of the FLT in order to continue its stability during use. Often, interchangeable equipment is placed on the market by manufacturers other than the FLT manufacturer. In these cases, the correct and safe coupling of the interchangeable equipment with the FLT is the responsibility of the manufacturers of interchangeable equipment, including the stability risk assessment. Thus, the interchangeable equipment manufacturer should have access to the relevant information of the FLT concerning operative and structural features and its configuration as a procedure for assessing the correct and safe coupling. Otherwise, he should perform experimental stability tests for each model of FLT so that its interchangeable equipment can be fitted. Specific research activity is developed in order to define an analytical procedure to assess the stability of FLT when assembled with interchangeable equipment. Specific typologies of FLTs and interchangeable equipment have been selected in order to better characterise the case study. The analytical equations mimic the static stability tests. The results achieved have been compared to experimental data in order to optimise the procedure. The results attained by the application of the analytical procedure to all the combinations of main typologies of FLTs and the interchangeable equipment selected showed good agreement with experimental tests.

Steroid hormones, such as 17β-testosterone, 11-ketotestorenone and 17β-estradiol, play an essential role not only in reproductive function but also are potential biomarkers of numerous additional functions in teleost fish. The presence of endocrine disruptor compounds in aquatic ecosystems has raised concern about their effect on hormone levels in fish target organs. Since hormones are present in very low concentrations in biological material, their determination still remains a challenge. A new analytical procedure has been developed to determine 17β-testosterone, 11-ketotestosterone and 17β-estradiol in the sea trout female and male gonads by liquid chromatography-tandem mass spectrometry (LC-MS/MS) system equipped with an ESI source operating in both positive and negative mode. Chromatographic separation of analytes was accomplished in Poroshell 120 EC-C18 (150 mm × 2.1 mm, 2.7 µm) column under isocratic elution conditions. The mobile phase consisted of acetonitrile, methanol and water (20:50:30/v/v/v) at a flow rate of 0.2 mL/min. Analytes were extracted from the gonad matrix with ethyl acetate, and co-extractives impurities were successfully removed by QuEChERS (quick, easy, cheap, effective, rugged and safe) method. The procedure was validated with good sensitivity, linearity, accuracy, and precision. Limits of quantifications were from 0.15 to 0.75 ng/g, linearity was obtained with correlation coefficient R > 0.99, accuracy was from 94.0 to 109.5%, precision expressed as RSD ranged from 1.7 to 27.2% (repeatability) and from 2.2 to 37.1% (reproducibility). Finally, the method was applied to determining 17β-testosterone, 11-ketotestosterone and 17β-estradiol in real samples of the female and male sea trout gonads, 8 and 22 samples, respectively.

The article analyses foreign and national recommendations on transfer of methods. It substantiates the need to adequately reproduce test methods that introduce a specific analytical procedure in testing laboratories - in order to be able to give a reliable assessment of the quality of substances and dosage forms. The article gives examples of a successful analytical method transfer, describes ways of transferring analytical procedures, cases when the transfer of method is not needed, and validation/verification parameters that are used to check whether the method is suitable for a particular laboratory. It also gives examples of validation parameters that are used in verification of pharmacopoeial methods, which are chosen based on the type of method and the tested parameter.

A diverse set of analytical tools is required to characterize the complex structural properties of biopharmaceutical products and to ensure their quality, stability, safety, and efficacy. It is generally necessary to demonstrate that such tools are capable of measuring one or more intended attribute(s) of the product with a desired degree of precision, accuracy, linearity, specificity and sensitivity. Here we present a general framework upon which experiments may be designed to establish analytical procedure performance, predicated on the hypothesis that many analytical procedures have universal performance characteristics – that is, the validity of the measured result is a function of the measurement system and data characteristics and is not a function of the specific analyte being measured. Using simulated data, we demonstrate that the generalized approach improves the scientific validity of resulting descriptions of procedure performance by reducing the incidence of false failures and missed faults during future use of the procedure. Broad adoption of these principles will facilitate an improved understanding of procedure performance characteristics while requiring fewer human resources for procedure qualification studies. [ABSTRACT FROM AUTHOR]

Resin-based composites are commonly used restorative materials in dentistry. Such tooth-colored restorations can adhere to the dental tissues. One drawback is that the polymerization shrinkage and induced stresses during the curing procedure is an inherent property of resin composite materials that might impair their performance. This review focuses on the significant developments of laboratory tools in the measurement of polymerization shrinkage and stresses of dental resin-based materials during polymerization. An electronic search of publications from January 1977 to July 2016 was made using ScienceDirect, PubMed, Medline, and Google Scholar databases. The search included only English-language articles. Only studies that performed laboratory methods to evaluate the amount of the polymerization shrinkage and/or stresses of dental resin-based materials during polymerization were selected. The results indicated that various techniques have been introduced with different mechanical/physical bases. Besides, there are factors that may contribute the differences between the various methods in measuring the amount of shrinkages and stresses of resin composites. The search for an ideal and standard apparatus for measuring shrinkage stress and volumetric polymerization shrinkage of resin-based materials in dentistry is still required. Researchers and clinicians must be aware of differences between analytical methods to make proper interpretation and indications of each technique relevant to a clinical situation.

The potential role of serotonin (5-HT) as a marker for identifying sensitivity to clinical diseases or behavioral disorders and for monitoring treatment emphasizes the need for reference values of serum 5-HT in dogs. Preanalytical factors such as patient variables, time of sample collection, specimen handling, storage time, and temperature can potentially cause variations to laboratory results. The aim of the present study was to evaluate canine serum 5-HT concentration measured by enzyme-linked immunosorbent assay and to propose standardized preanalytical conditions. Blood samples were collected from the cephalic vein, between 9.00 AM and 11.00 AM, from 120 healthy fasted dogs; the samples were then stored into anticoagulant-free tubes and centrifuged. The serum was stocked at −20°C and analyzed by enzyme-linked immunosorbent assay within 3 months from collection. Because the results were not normally distributed in the reference population, the 2.5 and 97.5 percentiles were calculated to characterize the 95% reference intervals (201-650 ng/mL, 361 median). For statistical analysis, the results were organized into 3 different groups based on the age of the dogs: 1-2 years old (n = 35), 3-7 years (n = 43), and 8-12 years (n = 42). 5-HT levels were higher in 3-7 years group than in other age groups, but no significant age-related dissimilarities were found (Kruskal-Wallis test, P = 0.08). The results of the present study contributed to establish reference intervals for serum 5-HT in dogs which could support both clinical researchers and veterinary behaviorists in designing studies and monitoring the effects of medications. Furthermore, we provide recommendations to decrease 5-HT measurement variation depending on preanalytical factors, to improve reliability and validity of serum measurements. [ABSTRACT FROM AUTHOR]

Abstract Knowledge of the in situ stress state of rock mass is fundamental for engineering, geological and geophysical applications. In situ stress state determination requires in principle the evaluation of the three principal stresses and the related principal directions, but it is widely recognized in the literature that the maximum horizontal stress is the most difficult component to accurately estimate. In the context of borehole methods, this paper proposes a step-by-step analytical procedure to estimate some bounds to the maximum horizontal stress, starting from a geomechanical description of the rock and relying on information generally available in the engineering practice. The procedure is divided in substeps, each one requiring additional information about the mechanical properties of the rock and on the geometrical properties of the failed portion of rock: more information available implies a lower uncertainty on in situ stress estimate. Furthermore, since the proposed procedure is analytical, it allows a complete and very easy implementation in a spreadsheet. The aim of the work is thus to provide a rigourous but simple analytical tool that can be used in engineering practicte to estimate some bounds to the maximum horizontal in situ stress state. The approach is finally validated by means of both numerical simulations, performed with a sophisticated numerical tool, and experimental field data coming from the literature. Highlights • Determination of in situ stress state is crucial for any underground application in many fields of engineering. • Borehole methods have been accepted to be one of the most reliable method to estimate in situ stress state. • A step-by-step analytical procedure is presented to estimate the in-situ stress state relying on drilled borehole information. • Any step of the procedure reduces of the bounds of the maximum horizontal stress, at the cost of more information required. • The procedure is validated by means of both simulations with advanced numerical methods and in situ literature data. [ABSTRACT FROM AUTHOR]

This study focused on improving the design of slender structures with reinforced concrete (RC) telecommunication towers as the main application. Analytical procedure based on Rayleigh's method to compute the first natural vibration frequency and the critical buckling load was development. All the nonlinearities present in the system were considered, in addition to the soil-structure interaction and the variation of the geometric properties along the length of the structure. The geometric nonlinearity and imperfections of the tower structure were computed as functions of the axial load using a geometric stiffness matrix. Further, the material nonlinearity was accounted for by reducing the flexural stiffness. As concrete structures exhibit viscoelasticity, creep was calculated using the Eurocode 2 model. The soil-structure interaction was modeled as a set of distributed springs. To validate the proposed method, the first frequency and critical buckling load were compared with those yielded by FEM simulations. The frequency results were in good agreement with those of the FEM simulations, indicating that the proposed method is sufficiently accurate for use in engineering design applications and easy to implement. On the other hand, the buckling load results obtained using the proposed method and FEM differed significantly, motivating further investigation. [ABSTRACT FROM AUTHOR]

Highlights • Condensed two-mass model of shaft line. Analytical solution of diff. eqs. of motion. • Simplified multi-mass model of shaft line. Rayleigh-Ritz method. Analytical solution. • Formulation of cylinder torque and engine primary and secondary torque. • Physically based transfer factor of engine excitation to shaft response. • Comparison with FEM. Verification by measurement. High accuracy. Abstract In this paper two relatively simple analytical procedures for free and forced torsional vibration analysis of ship power transmission systems are developed. In the first, approximate procedure, the shaft line is modelled as a two-mass system and analytical solution of the differential equations of motion is given. In the second one, a multi degree of freedom (d.o.f.) problem of the complete propulsion system is solved by the Rayleigh-Ritz method. A special attention is paid to the determination of the contribution of each cylinder to the primary and secondary engine torques by taking into account the firing order. The application of the two procedures is illustrated in the case of a typical propulsion system of a merchant ship with a slow-speed main engine connected directly to the propeller by a relatively short shaft line. The obtained results are verified by a comparison with measurements. All classification societies require calculation of the propulsion system operating parameters, but they do not provide simplified formulae for vibration analysis. The outlined analytical procedures can be used for the estimation of torsional vibration of the shaft line in the preliminary ship design stage as well as for ships in service. [ABSTRACT FROM AUTHOR]

This paper focuses on the point-to-point X-RAD connection system for the construction of cross laminated timber buildings in earthquake prone areas. Tests on X-RAD connectors subjected to “shear-tension” and “shear-compression” loading configurations are presented as supplement to the experimental data provided in previously published research. Tests aimed at characterizing the behavior of timber walls assembled with the system and loaded by lateral force are also reported. A capacity domain that allows for quick safety checks for any given load combination on the connector was derived from the experimental outcomes and is presented herein. An extremely simplified, yet effective numerical approach (the connector behavior is reproduced by 3-link elements) is proposed and compared with the experimental evidence. The 3-link model was able to reproduce with sufficient accuracy both, the elastic and post-elastic response of the walls. In the discussion section, particular attention is given to the system capability of dissipating energy and exhibiting ductile behavior. [ABSTRACT FROM AUTHOR]

Radial joints are defined as the contact part between precast segments in each ring of mechanical excavated tunnel lining. The behavior of flat radial joints without connectors is investigated in this paper through full-scale experimental tests on fiber reinforced concrete elements without any traditional reinforcement. The tests were performed by imposing a joint opening, as typical can occur when higher level of ovalization in the lining are required. The results showed the effect of concrete crushing as well as the bursting phenomena. Finally, an analytical interpretation of the behavior is presented, providing useful information that can support the design of this type of joints. [ABSTRACT FROM AUTHOR]

While UHI mitigation potential of cool roofs has been deeply investigated compared to cool façades, still not sufficient research effort has been dedicated to quantify the benefits of combined cool building products. The present work evaluates the thermal performance of an innovative cool roofing membrane and a cool façade painting applied on a prototype building. Moreover, an analytical procedure able to predict the cool coating thermal performance is elaborated. Such methodology can be used to determine the passive cooling potential of each product as a separate envelope component and as a combination. To this twofold aim, a preliminary in-field monitoring is developed. Therefore, a sensitivity analysis is performed to evaluate the separate and combined passive cooling contributions of the roof and the differently oriented façades. Finally, the analytical procedure is developed to define external surface temperature profiles able to predict the building coating thermal performance by minimizing the number of temperature measurements. Results show the major contribution of cool roof membrane in reducing indoor operative temperature. Nevertheless, a non-negligible cooling effect in terms of outdoor surface temperature is imputable to the South cool façade. Moreover, the analytical model shows an acceptable accuracy in representing the behavior of the building coating. [ABSTRACT FROM AUTHOR]

Resin-based composites are commonly used restorative materials in dentistry. Such tooth-colored restorations can adhere to the dental tissues. One drawback is that the polymerization shrinkage and induced stresses during the curing procedure is an inherent property of resin composite materials that might impair their performance. This review focuses on the significant developments of laboratory tools in the measurement of polymerization shrinkage and stresses of dental resin-based materials during polymerization. An electronic search of publications from January 1977 to July 2016 was made using ScienceDirect, PubMed, Medline, and Google Scholar databases. The search included only English-language articles. Only studies that performed laboratory methods to evaluate the amount of the polymerization shrinkage and/or stresses of dental resin-based materials during polymerization were selected. The results indicated that various techniques have been introduced with different mechanical/physical bases. Besides, there are factors that may contribute the differences between the various methods in measuring the amount of shrinkages and stresses of resin composites. The search for an ideal and standard apparatus for measuring shrinkage stress and volumetric polymerization shrinkage of resin-based materials in dentistry is still required. Researchers and clinicians must be aware of differences between analytical methods to make proper interpretation and indications of each technique relevant to a clinical situation. [ABSTRACT FROM AUTHOR]

Nutrient analysis is used to estimate nutrient content of crop plants to manage fertilizer application for sustained crop production. Direct solid analysis of agricultural and environmental samples by energy dispersive X-ray fluorescence spectrometry (EDXRF) was chosen as alternative technique to evaluate the simultaneous multielemental quantification of the most important essential elements in coffee (Coffea arabica L.) plants. Inductively coupled plasma atomic emission spectrometry and certified reference materials made from leaves were used to calibrate and check the trueness of EDXRF method for the determination of the concentration of several nutrients in coffee leaves and branches. Fluorescence spectrometry proved to be advantageous and presented low cost as loose powder samples could be used. Samples collected from a field experiment where coffee plants were treated with excess of Ni and Zn were used to verify the practical application of the method. Good relationships were achieved between certified values and data obtained by EDXRF, with recoveries ranging from 82 to 117 %.

In situ cosmogenic 26Al/10Be burial dating, one of the dating methods that has emerged over the past several years, has been widely applied in geomorphology, archaeology and other science disciplines. The chemical recovery and purity of Al is one of the key factors to yield high-precision age results. Further improvements are needed for several steps for separating and purifying Al in the current chemical procedure of Purdue University. Based on results of conditional experiments, this study proposes the following suggestions for refining the procedure: 1) 38-75 μm, instead of 75-150 μm, anion exchange resin should be used to reduce the volume of eluting solution (0.05 mol/L H2C2O4-0.5 mol/L HCl) and to separate Al from its major interference elements of Fe and Ti; 2) Cation exchange resin be used to extract Al from H2C2O4-HCl solution to avoid the time-consuming decomposition of H2C2O4 by chemical reagents. The analyses of simulating samples show that quasi quantitative recovery of Al is realized by using the above two refined steps and the whole procedure recovery of Al reached 91%±5% with a purity of 98%.

Prediction of the roll motion is considered as an important problem in planing hull motion, since safety of the craft highly depends on it at high speeds. Accordingly, the main aim of the present study is to analyze this motion in time domain and estimate its amplitude at various frequencies. In many of the earlier works performed for predicting the motion of planing hulls, the 2d + t theory has been used. However, in all of these studies, water entry phenomenon was modeled without considering the asymmetric condition. In order to overcome this problem, a mathematical model is hereby proposed for prediction of the roll motion which is derived by applying an analytical model of the water entry in which asymmetric condition is taken into account. The suggested method may be used for the warped planing boats. Validity of the model is examined by comparing the obtained results against different experimental results. Another objective of the present study is to examine the effects of deadrise angle, longitudinal center of the gravity and the hullform on the amplitude of motion and hull response. The response is investigated at different conditions: (1) sinusoidal exciting moment, (2) a fixed existing moment and (3) an initial roll angle without any exciting moment. The proposed model is also used to evaluate the horizontal forces and moments acting on the hull during the roll motion. [ABSTRACT FROM AUTHOR]

In this study, a practical analytical procedure is introduced for determining the stability robustness map of a general class of linear‐time invariant fractional‐order systems with single and multiple commensurate delays of retarded type, against delay uncertainties. The complexity arises due to the exponential type transcendental terms and fractional order in their characteristic equation (CE). It is shown that this procedure analytically reveals all possible stability regions exclusively in the parametric space of the time delay. Using the presented method in this study, first, the authors will eliminate the transcendental terms of exponential type from the CE and then, they can determine all the locations where roots pass through the imaginary axis. By definition of root tendency on the boundary of each interval, the number of unstable roots in each region is calculated. Finally, the concept of stability is expressed in the intervals of delay values. The effectiveness of the proposed method results is illustrated via six numerical examples and to gain a better understanding of the problem, the root‐locus curve of these systems has been depicted as a function of delay parameter changes. [ABSTRACT FROM AUTHOR]

Partition coefficient, P , is the preferred descriptor of molecular lipo- or hydrophilicity, and thus of relationships between a solute ( S , e.g., a drug), a polar medium ( W , e.g., an aqueous buffer), and an essentially apolar, organic, medium or a drug carrier ( O ). The coefficient is commonly identified with the linear ratio of solute quantities in the two media, P = n SO / n SW , even to characterise solute association with or binding to a surface (e.g., of a HPLC column or a drug carrier). To check the latter practice correctness—and credibility of the prevailing P definition—this paper compares an ideal solute distribution between two separate homogeneous fluid media (i.e., partitioning) to solute association with a uniform surface immersed in one such medium (i.e., binding). This reveals that solute partitioning and binding fundamentally differ and can only exceptionally be described, or analysed, with similar equations. Nonlinearised formulae that describe partitioning (Eq. (9) ) and binding (Eq. (11) ) can yield similar lipophilicity descriptor values only if solute preparation is relatively dilute; employing a large organic medium fraction is helpful in this respect. Additional prerequisites for partitioning and binding models match are: 1:1 stoichiometry at the association maximum and identical interfacial area of solute and organic medium molecules. If these requirements are not met, binding model yields different, potentially somewhat higher, but more often up to > 10 times lower results than partitioning model. The main reason is saturation of organic medium with solute molecules. Partitioning model excludes this phenomenon, which cannot always be prevented by focussing on dilute solute preparations. The current practice of using a linear model and approximate equations to study partitioning or binding can cause large errors ( > 10 3 × ) , and is one possible reason for the notoriously high experimental log P values scattering. The latter makes log P predictions more difficult and less reliable than they could be if the measured data were evaluated with non-linearised partitioning or binding equations, as appropriate. [ABSTRACT FROM AUTHOR]

Terrestrial in situ -produced stable cosmogenic isotope 21 Ne can provide us lots of important geomorphologic information, while the prerequisite for the application of cosmogenic 21 Ne in the surface process studies is the accurate measurements of three neon isotopes in the rock samples. To employ cosmogenic 21 Ne in solving geological problems, we established a new analytical procedure of neon measurements on the GV 5400 noble gas mass spectrometer. Isobaric interferences on three neon isotopes have been quantified, and among them the correction for the major interference from 40 Ar 2+ on 20 Ne + was studied in more detail. Instead of the first-order correlation of 40 Ar + / 40 Ar 2+ ratio with the H 2 partial pressure in the ion source section of the mass spectrometer reported by Professor Niedermann and co-workers in 1993, an excellent power function correlation of the 40 Ar 2+ counting to that of 40 Ar + has been established in our analytical system for determining the unresolved 40 Ar 2+ contribution by monitoring the 40 Ar + signal during sample analysis. The calibration experiment using air standard was performed, and then several aliquots of quartz standard CREU-1 were measured to assess the performance of our neon measurements. The average measured cosmogenic 21 Ne concentration of CREU-1 (347 ± 7.7 × 10 6 atom g −1 ) is consistent with the published value (348 ± 10 × 10 6 atom g −1 ), which demonstrates the good analytical accuracy (0.3%) and high measurement precision (2.2%) of our neon measurements. And the MSWD value of 0.49 indicates the good agreement of the apparent dispersion of three aliquots data with their individual measurement errors. The establishment of this analytical procedure for neon measurement provides us a promising way for developing the cosmogenic 21 Ne method in many fields of Earth sciences and beyond. [ABSTRACT FROM AUTHOR]

A new simple analytical procedure (AASHTO modified) that includes the effect of the induced stress due to backfill compaction for use with conventional design methods of geosynthetic reinforced soil (GRS) walls is proposed. The proposed analytical procedure may be used with any conventional design methods that do not take into consideration the effect of the compaction-induced stress in their calculations. This approach is based on an equation suggested by Wu and Pham (2010) to calculate the increase in lateral stress in a reinforced soil mass due to compaction. Additionally, two numerical procedures for modeling of compaction are described. Analyses using these procedures were performed to evaluate the capability of the proposed analytical procedure. The results were compared with values predicted using the Ehrlich and Mitchell (1994) method, the modified version of the K -stiffness method (Bathurst et al., 2008) and the AASHTO simplified method. The results show that the AASHTO modified method and the numerical analyses, in which the compaction-induced stress was modeled using two distributed loads at the top and bottom of each soil layer, resulted in values of the maximum reinforcement tension, T max , that agree with those from the full-scale test and those calculated by Ehrlich and Mitchell (1994). On the other hand, the K -stiffness method under-predicts the measured T max values. Moreover, numerical modeling of compaction using a distribution load only at the top of each soil layer overestimated the measurements. [ABSTRACT FROM AUTHOR]

Chemical hazards may occur in any phases of the different livestock production systems. Aim of this review is to address an update about the key issues related to the risk of contamination in foods of animal origin by environmental contaminants linked to industrialisation or urbanisation (e.g., heavy metals and persistent organic pollutants), and natural contaminants (e.g., mycotoxins). This review deals with current issues and future perspectives on the complex issue of the safety of feeds and foods of animal origin, by taking into account the estimation of the occurrence of chemical residues in food, the hazard identification and characterisation of mycotoxins in animal feeds, and the analysis of feedstuffs as a tool to control and evaluate food safety. [ABSTRACT FROM AUTHOR]