Direct Comparison Method Research Articles

Method for evaluating the human bioequivalence of acarbose based on pharmacodynamic parameters.

ObjectiveTo explore a method for evaluating the bioequivalence of acarbose based on pharmacodynamic parameters using a single-dose, randomized-sequence, three-way crossover study of acarbose test (T) and reference (R) formulations.MethodsBaseline-adjusted, pre-dose value deduction, and direct comparison methods were used to evaluate the geometric T/R ratios and 90% confidence intervals (CIs) of the ln-transformed pharmacodynamic parameters to identify the most suitable evaluation system. Twelve participants were randomly divided into three groups to receive treatment in the following sequences: TRR, RTR, and RRT, each including a 7-day washout period between treatment periods. The serum glucose concentration (baseline) was determined. Pharmacodynamic parameters, including the maximum reduction in serum glucose concentrations (ΔCSG,max) and difference of the AUC of glucose between before and after acarbose exposure (ΔAUEC), were tested.ResultsUsing the direct comparison method, the geometric mean ratios of CSG,max, AUEC(0-2h), and AUEC(0-4h) were 94.13%, 97.82% and 99.76%, respectively. The 90% CIs of the geometric T/R ratios for CSG,max, AUEC(0-2h), and AUEC(0-4h) all fell between 80% and 125%. Conversely, ΔCSG,max and ΔAUEC(0-4h) were less reliable measures of acarbose bioequivalence.ConclusionsPre-dose value deduction and direct comparison methods can be initially considered suitable for assessing acarbose bioequivalence.

Water sources of riparian plants based on stable hydrogen and oxygen isotopes in Lanzhou section of the Yellow River, China

As plant species for riparian ecological restoration in northern China, Tamarix ramosissima and Salix matsudana play an important role in river protection, flood control, regional climate regulation, and landscape construction of riparian vegetation. Two sampling sites were selected in the riparian zones along the Lanzhou section of Yellow River, where plant xylems and potential water sources were collected. The direct comparison method, Bayesian mixture model MixSIAR and the proportional similarity index (PS index) were used to determine the proportions of water utilization for each potential water source and the relationship of two species in water utilization. The results showed that shallow soil (0-30 cm) was the main water source during growing season, with utilization ratio being 28.3% for T. ramosissima and 24.4% for S. matsudana. For T. ramosissima, river water had the lowest contribution (16.6%), and for S. matsudana, groundwater contributed the least (17.9%). In the months with low soil moisture, plants increased the utilization ratios of river water and groundwater. The PS index at the sampling site S1 and S2 was 91.0% and 87.7%, respectively. On a monthly basis, the index in May was the highest, indicating an inter-month divergence in water use relationship. At the floodplain, there were even utilization ratios for each potential water source, which is an optimal strategy to obtain water from each potential source to the maximum extent. Our results provided theoretical basis for riparian tourism development along the Lanzhou section of the Yellow River and plant water management in environment protection in the Yellow River Basin.

In-situ strain- and temperature-control X-ray micro-diffraction analysis of nickel–titanium knitted architectures

The reversible phase transformation between B2 austenite phase and B19’ martensite phase is the governing mechanism behind the exciting active and passive capabilities of Nickel–Titanium (NiTi) knitted architectures. NiTi knitted architectures are manufactured from a monofilament fiber of originally-straight NiTi wire that is bent into an interlocking network of adjacent loops. Depending on the thermo-mechanical load path, NiTi knitted architectures can provide excellent isothermal energy-absorption using the superelastic effect (SE) or function as large-deformation actuators that respond to thermal inputs using the shape memory effect (SME). The magnitude of NiTi knitted architecture characteristic performance metrics is dependent on the ability of the knitted architecture to undergo the reversible phase transformation, which is a function of the material stresses, strains, and temperature. This research quantifies the NiTi knitted architecture austenite phase fraction of the highly stressed filament surface in X-ray diffraction experiments as a function of the measurement position on the knitted loop and applied thermo-mechanical loading conditions. A Bruker D8 Discover 2D micro-diffractometer was equipped with a custom tensile straining- and temperature-control device. The Direct Comparison Method was employed to derive the austenite phase fraction from the X-ray diffraction patterns. This research establishes novel in-situ strain- and temperature-control X-ray micro-diffraction experiments and provides understanding of the governing deformation modes in NiTi knitted architectures.

An indirect comparison quasi-static calibration method for piezoelectric pressure sensors based on an inverse model

This graph represents the design schematic of an inverse model, which is used to predict the reference pressure curves and reference peak pressures. The inverse model is established using a linear second-order difference equation. It is supposed that p represents the input pressure curve of the calibrated sensor and y represents the voltage response curve of the calibrated sensor. The input pressure curve of the calibrated sensor is the average response curve of the reference pressure sensors. Where y (1) represents the 1-derivative of y , and y (2) represents the 2-derivative of y . • An novel indirect comparison quasi-static calibration method for piezoelectric pressure sensors was proposed. • An inverse model was established to predict reference pressures. • Reference pressure sensors were used only once during the acquisition of modeling data of the inverse model. • The calibration accuracy of the proposed method was compared with the direct comparison quasi-static method. Quasi-static calibration is an effective method to ensure the measurement accuracy of piezoelectric pressure sensors. In this paper, a novel indirect comparison quasi-static calibration method is proposed. An inverse model is established by a linear second-order differential equation and used to predict reference pressure curves and reference peak pressures. The working principle of the drop-weight device and calibration steps are described. Calibration tests show that the inverse model has good prediction accuracy. Compared with the peak pressures measured by the reference pressure sensors, the maximum prediction error of the peak pressures calculated by the inverse model is 0.29%. Reference pressure sensors are used only once during the acquisition of modeling data of the inverse model, which can effectively extend the service life of the reference pressure sensors. Furthermore, the proposed method has good calibration accuracy as well as the direct comparison method.

Assessment methods of the basic parameters of the combustion process in reciprocating internal combustion engines

The article presents selected methods of assessing the basic parameters of the combustion process, as well as assessing the usability and limitations of the methods used to determine the initiation and the end of the combustion process in reciprocating internal combustion engines. The methods considered are based on data contained in real, developed indicator diagrams. Basic thermodynamic assumptions and the scope of application of the combustion process evaluation method based on the actual work cycle of a combustion engine prepared in a double logarithmic scale were discussed. The article also mentions the application of the following methods: a direct pressure comparison method in the cylinder, the comparison of the first pressure derivative in the cylinder, logarithmic derivative method of pressure change in the cylinder, the method of the polytropic index, method of the first derivative of the polytropic index and the method of constant values of the polytropic index. The article presents the advantages and disadvantages of the research of our methods.

Multi metal oxide NiO-CdO-ZnO nanocomposite–synthesis, structural, optical, electrical properties and enhanced sunlight driven photocatalytic activity

In this article, ternary oxide NiO-CdO-ZnO nanocomposite along with pure NiO, CdO and ZnO were prepared by the homogeneous co-precipitation method. The XRD pattern confirmed the formation of nanocomposite with NiO (cubic)–CdO (cubic)–ZnO (hexagonal). The volume fractions were 38% NiO, 6% CdO and 56% ZnO phase in nanocomposite determined by direct comparison method. Crystallite size and lattice strain were calculated using Scherrer plot, Williamson-Hall and Size-Strain plot methods. The UV–vis was used to study optical properties such as bandgap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric constants (εr, εi). FTIR and Raman analyses have confirmed the successful formation of NiO-CdO-ZnO nanocomposite. The current-voltage measurements revealed that nanocomposite has high electrical response. SEM images shown that nanocomposite has roughly spherical morphology and EDX described that Zn has higher concentration than Ni and Cd. PL spectra of nanocomposite demonstrated the emission bands associated with new energy levels induced by defects. The photocatalytic activity of grown nanocomposite against rhodamine B (RhB) and methylene blue (MB) dyes under sunlight revealed high degradation efficiency 99% for RhB and 98% for MB in 60 and 90 min illumination respectively, indicated that grown nanocomposite is a propitious sunlight-driven photocatalyst to eliminate organic toxins.

PENINGKATAN KEMAMPUAN KALIBRASI STOPWATCH -TIMER DIGITAL 3 DIGIT DI PUSLIT METROLOGI-LIPI MELALUI METODE TOTALIZED

RCM-LIPI capability in the field of stopwatch-timer calibration has improved through totalized method. In this study, we compared the measurement results using the direct comparison method and the totalized method, using the same unit under test (UUT) which is the Casio 401Q21R digital stopwatch with 10 -3 resolution and also with the same measuring point. Measurements in both direct and totalized calibration methods were performed with five data retrievals for each measuring point, i.e. 10 s, 20 s, 30 s, 40 s, 50 s and 60 s . The value of the measurement uncertainty has been successfully improved one order of magnitude. As a result, the human reaction time standard deviation, HRTSD : u HRTSD has significant influence to the combined uncertainty. The result of calculation of u HRTSD in calibration system using totalized method is better than calibration system using direct comparison method.

Direct Comparison and Triple Collocation: Which Is More Reliable in the Validation of Coarse‐Scale Satellite Surface Albedo Products

AbstractA rigorous and reliable validation is the prerequisite and basis to properly understand the accuracy of satellite surface albedo products. However, the representativeness error of point scale in situ measurements, which mainly results from the spatial mismatch between in situ and satellite measurements as well as the surface heterogeneities, generally hinders an effective validation of satellite surface albedo products based on the conventional direct comparison method. Triple collocation technique has been recognized as a powerful tool to estimate the errors of satellite products without requiring the truth. Here, we evaluated the effectiveness of both the direct comparison and extended triple collocation (ETC) methods in tackling with the representativeness error of in situ measurements and characterizing the performances of satellite surface albedo products (MCD43A3 [V006], GLASS, and NPP VIIRS albedos) given whether the in situ‐based pixel‐scale albedo was available or not. The ETC method is shown to be advantageous over the direct comparison based on single “point” in situ measurements, because it is less affected by representativeness errors. However, it shall not substitute for the direct comparison method based on in situ‐based pixel‐scale albedo measurements, because its effectiveness in solving representativeness errors and estimating product errors is very limited and dependent on the choice of the data in the triplets. Furthermore, the ETC technique cannot be used to estimate the true physical errors of satellite surface albedo products.

Teaching kinetic energy as an observable quantity

In this paper we present a novel approach to teach kinetic energy as an observable and measurable concept. The fundamental principles have been outlined for gravitational potential energy in an earlier work, that we extend here. By accelerating or decelerating bodies with springs we begin, in a first step, with a direct comparison method for kinetic energies. A second step addresses the quantification of kinetic energy by introducing reference units. Third, we construct a mechanical calorimeter that generates these countable energy portions. And finally, in a fourth step, a quantitative description leads to the fundamental equation, that relates kinetic energy to velocity and mass. We highlight the concept by giving examples that were used and evaluated in high school physics classes.

Austenite reversion in AISI 201 austenitic stainless steel evaluated via in situ synchrotron X-ray diffraction during slow continuous annealing

In situ synchrotron X-ray diffraction was used to track real-time austenite reversion in AISI 201 austenitic stainless steel deformed to a true strain of 0.34 under tensile testing. The deformed material was continuously annealed from 100 °C up to 800 °C at a heating rate of 0.05 °C s−1. Phase changes and microstrain partitioning were evaluated by means of the direct comparison method and modified Williamson-Hall plots, respectively. The microstructure of the deformed steel consists of γ, ε- and α′-martensite with volume fractions of 0.24, 0.07, and 0.69, respectively. ε → γ reversion occurs within the temperature range of 150–400 °C through a shear mechanism. The starting (As) and finishing (Af) temperatures for α’ → γ reversion are 486 °C and 770 °C, respectively. Three stages were distinguished for this reaction. By evaluating the crystallite size of both γ- and α′-phases, it can be inferred that α' → γ reversion is diffusion-controlled. Such results were corroborated by thermodynamic simulations to assess the driving force for γ-formation. Microstructural aspects such as γ-nucleation sites, in-grain misorientation, grain refinement, and crystallographic texture were investigated by means of electron backscatter diffraction. Fresh formed ultrafine austenite grains hold different crystallographic orientations than those of untransformed austenite.

Comparative Analysis between the Value of Biological Assets and Agricultural Products, Using Market Approaches and Income Approaches in the Post PSAK 69 Agriculture at Palm Oil Plantation

Property of palm oil plantation is income producing property in which oil palm is the most important commodity which has the biggest contribution to the creation of values. Palm oil plants are biological assets which experience growth transformation and need a long period from seedlings to productive plants. Therefore, it is necessary to have the measurement which can indicate the value of the property appropriately according to its contribution. Cost model is usually used in presenting financial statement which is referred to PSAK 16 on fixed asset that does not reflect the real quality of asset since it is only recorded its cost. PSAK 69 agriculture applies fair value to respond to some uniqueness of the agricultural characteristics of oil palm. The objective of the research was to analyze the difference between the value of biological assets and agricultural products by using market and income approach. The research used quantitative case study approach which was aim to assess oil palm plants at private estate in Kabupaten Langkat. Direct comparison method was used for market approach while Discounted Cash Flow (DCF) was used for income approach. The data were gathered through internal report analysis and semi-structured interviews. The result of the research showed that the value of biological assets in pre-PSAK 69 was IDR.121,140,000,000 while in the post-PSAK 69 the recorded value consisted of two parts: fair value of bearer plants and fair value of agricultural products. Through market approach, it was found that fair value of bearer plants was IDR.118,083,410,741 and fair value of agricultural products was IDR.3,056,589,259. Through income approach, it was found that fair value of bearer plants was IDR.110,354,000,000 and fair value of agricultural products was IDR.10,786,000,000. The conclusion was that the difference in fair value of agricultural products, assessed by using market approach and by using income approach, was 252.9%.

Remarks concerning about the characteristics of the extractor vacuum gauge and the Quadrupole Mass Spectrometer

In this study, the stability of an extractor gauge (EXG) was investigated through the determination of correction factors (CFs) over a pressure range 5 × 10−5 Pa to 9 × 10−3 Pa by using a Spinning Rotor Gauge (SRG) traceable to UME Static Expansion System, during 20 months and 15 months for N2 and He, respectively. Percent and fractional changes in CFs were studied and sensitivities of EXG were also presented for Ar and CO2. Direct comparison method was used for EXG stability measurements. Additionally, sensitivity measurements of Quadrupole Mass Spectrometer (QMS) were performed in the range of 1.0 × 10−6 Pa to 1.0 × 10−2 Pa at emission currents of 2 mA, 0.4 mA and 0.1 mA for He, N2 and Ar. Long-term stabilities of QMS for N2 and He were analyzed for about 2 years. EXG and SRG were used for QMS sensitivity measurements.The changes in CF of EXG remained within ±5% and ±6%, and fractional changes remained within about ±0.03 and ±0.05 for seven and five different measurement runs for N2 and He, respectively. The change in CF of EXG based on the mean value of the relevant pressure point is 5.8% and 7.8% at 5 × 10−5 Pa, 5.3% and 5.9% at 9 × 10−3 Pa, and maximum CF changes relative to the first calibrations ranges from −1.7% to 2.4% and from −1.0% to 4.7% within the selected pressure range for N2 and He, respectively. The changes of QMS sensitivity are strongly dependent to the electron current. Maximum changes of QMS sensitivities over a three month period are 44% and −35% for N2 and He, respectively. This study was conducted in the frame of EMRP IND12 “Vacuum Metrology for Production Environments” project that was funded by the European Metrology Research Programme (EMRP).

Metrological Characterization of Non-Rotating Low-Pressure Piston-Cylinder Unit System

A Low-pressure non-rotating new piston gauge covers the range of gauge and absolute pressure from less than 1 Pa to 15 kPa in gas media [1]. The instrument operates on the piston gauge principle. However, the force resulting from pressure on the piston is measured by a force balanced load cell rather than a balanced system against masses subjected to the acceleration due to gravity. For this reason, the measuring portion is designated a force balanced piston gauge (FPG) [1]. While pressure measurement range of a conventional pressure balance can start from around 5 kPa, as the FPG can measure pressure starting from a few pascal. Calibration or determination of the effective area of FPG system can be done using a conventional pressure balance reference instrument gauge in gauge and absolute modes. This paper describes the metrological characterization of a low-pressure non-rotating piston-cylinder unit both in absolute and gauges pressure modes, in the range of 1 Pa to 15 kPa by direct comparison method.

Online low-field NMR spectroscopy for process control of an industrial lithiation reaction-automated data analysis.

Monitoring specific chemical properties is the key to chemical process control. Today, mainly optical online methods are applied, which require time- and cost-intensive calibration effort. NMR spectroscopy, with its advantage being a direct comparison method without need for calibration, has a high potential forenabling closed-loop process control while exhibiting short set-up times. Compact NMR instruments make NMR spectroscopy accessible in industrial and rough environments for process monitoring and advanced process control strategies. We present a fully automated data analysis approach which is completely based on physically motivated spectral models as first principles information (indirect hard modeling-IHM) and applied it to a given pharmaceutical lithiation reaction in the framework of the European Union's Horizon 2020 project CONSENS. Online low-field NMR (LF NMR) data was analyzed by IHM with low calibration effort, compared to a multivariate PLS-R (partial least squares regression) approach, and both validated using online high-field NMR (HF NMR) spectroscopy. Graphical abstract NMR sensor module for monitoring of the aromatic coupling of 1-fluoro-2-nitrobenzene (FNB) with aniline to 2-nitrodiphenylamine (NDPA) using lithium-bis(trimethylsilyl) amide (Li-HMDS) in continuous operation. Online 43.5 MHz low-field NMR (LF) was compared to 500 MHz high-field NMR spectroscopy (HF) as reference method.

The Agricultural Water Rebound Effect in China

Although the water productivity of the agricultural sector in China continuously increased over the last twenty years, by improvements in irrigation technology, the total agricultural water use did not decline as expected, mainly due to continuous increases in agricultural output partially derived from technological progress. Thus, agricultural water use in China may experience a rebound effect. This study defines the water rebound effect (WRE) using macro-scale indicators of water use and water productivity, establishes a simplified direct comparison method using the contribution rate of technological progress, and evaluates the magnitude of the macro-scale water rebound effect in the Chinese agricultural sector using provincial panel data from 1997 to 2014. The magnitude of the agricultural WRE in China (1998–2014) is 61.49%. The northern and western regions of China experience a greater WRE than the southern and eastern regions, and the changes in the inter-annual WRE are distinct. These observations indicate that much of the expected water savings from efficiency improvement could be offset by increased water use for increased agricultural production due to technology enhancement. The control of water use growth is effective for reducing the water rebound effect. The study confirmed the existence of the agricultural WRE in China.

Enantiomeric characterization and structure elucidation of LH601A using vibrational circular dichroism spectroscopy

LH601A is a novel non-reactive chiral molecule inhibiting Keap1-Nrf2 protein-protein interaction. The absolute configuration (AC) was independently determined in this study using vibrational circular dichroism (VCD) spectroscopy. Because of band overlapping and broadening in the IR spectrum, a direct VCD spectrum comparison method is devised without the conventional IR band alignment. Being an unbiased AC inquiry, all possible chiralities are evaluated based on the statistical analysis of VCD similarity, Sv. The AC of three-center stereoisomer LH601A is unambiguously assigned to (S,R,S). A comparative study was also carried out to investigate the structural and energy differences of calculated conformers using the polarized continuum model of dimethyl sulfoxide.

Amplitude Calibration in Terahertz Time-Domain Spectroscopy Using Attenuation Standards

An amplitude calibration method for a terahertz time-domain spectroscopy system (THz-TDS) is proposed and demonstrated for transmittance measurement. The method is based on a direct comparison method using a terahertz attenuator as a reference standard. The measurement uncertainties of the THz-TDS are evaluated in transmittance measurements of metalized film attenuators as test samples. The relative expanded uncertainty is found to be 6.4–14.0% (k = 2) at 1 THz for transmittances ranging from 1 to 0.001. In addition, the calibration capability is extended to the available frequency range of the THz-TDS by considering spectral flatness of the reference standard. Validations of the method are also conducted by comparing the measurements between different systems, and it is confirmed that they agree well with each other.

Phase Comparison Method for Wide-Frequency-Range Microwave Photonic Signals

The goal of this study is to establish a phase comparison method using high-frequency microwave photonic signals. The signal is generated as a beat frequency of a dual-wavelength optical signal. We propose a double differential phase comparison method suitable for a phase-locked loop. This is achieved by using an optical frequency shifter and two low-frequency photomixers (optical-to-electrical signal converters). The basic approach of the method is that the phase difference between the high-frequency dual-wavelength signals can be measured as a differential phase of the detected low-frequency microwave signals by two respective low-frequency photomixers without high-frequency photomixers. With this approach, the phase comparison of any range of frequencies of the dual-wavelength signals can be performed by two identical low-frequency photomixers. In an application of this method for separate fiber-coupled stations, a common laser signal transmission is effectively carried out with a dual-wavelength optical signal. We conducted an experiment to verify the effectiveness of the double differential phase comparison method by comparing the direct phase comparison method.

실시간 다중항법을 이용한 관성측정기의 비행환경 성능 검증 기법

본 논문에서는 고기동 항체 적용을 위한 관성측정기의 비행환경 특성을 분석할 수 있는 방법을 제안한다. 먼저 관성측정기의 센서 출력을 직접 비교하는 방법을 제안하고, 시험결과를 통하여 장 단점을 분석하였다. 관성측정기의 센서 출력을 비교하는 방법의 단점 보완과 항법 해를 비교할 수 있는 방법을 제안한다. 이를 위해 유도전자장치를 이용하여 실시간 다중 항법 연산이 가능하도록 구현하였다. 제안한 방법은 유도전자장치를 이용하기 때문에 시스템의 안정성과 타 구성품의 영향도 등을 고려해야 한다. 따라서 실시간 다중 항법 연산이 가능하도록 구현된 내용을 기술하고, 제안한 방법의 검증을 위해 지상시험과 비행시험을 수행하였다. 시험 결과를 통해 제안한 방법은 관성측정기 개발의 신뢰성을 향상하는데 기여함을 확인하였다. Abstract It is necessary to verify the properties of an inertial measurement unit in the flight environment before applying to military applications. In this paper, we presented a new approach to verify an inertial measurement unit(IMU) in regard to the performance and the robustness in flight environments for the high-dynamics vehicle systems. We proposed two methods for verification of an IMU. We confirmed normal operation of an IMU and properties in flight environment by using direct comparison method. And we proposed real time multi-navigation system to complement the first method. The proposed method made it possible to compare navigation result at the same time. Therefore, it is easy to analyze the performance of an inertial navigation system and robustness during the vehicle flight. To verify the proposed method, we carried out a flight test as well as an experimental test of flight vibration on the ground. As a result of the experiment, we confirmed flight environment properties of an IMU. Therefore, we shows that the proposed method can serve the reliability improvement of IMU.

Analysis of water sources of plants in artificial sand-fixation vegetation area based on large rainfall events.

Water is a major limiting factor for plant growth in arid and semi-arid regions. To find out the main sources of water for two artificial sand-fixation plants (Caragana korshinskii and Artemisia ordosica), we analyzed the characteristics of hydrogen and oxygen stable isotopes in water molecules of rainfall, soil water and xylem water. To analyze water sources of these two plants, we used a direct comparison method and a multi-variate mixed linear model. The results showed that an equation of local meteoric water line in Shapotou was δD=7.83δ18O+5.64 (R2=0.91). The value for rainfall δ18O varied during plant-growing season, which was higher in the beginning and end of growing season, and lower in the peak of growing season. The value for soil water δ18O in the upper layers changed dramatically. The change range became smaller in the deeper soil layer. C. korshinskii had a greater efficiency (56.1%) in utilizing soil water in 40-80 cm soil layer. A. ordosica had a utilizing efficiency of 56.4% in 20-60 cm soil layer. A week after rain event, C. korshinskii and A. ordosica showed a higher efficiency in upper soil water. C. korshinskii showed an increase of 12.5% in utilizing soil water in 0-40 cm soil layer and A. ordosicas showed an increase of 10% in utilizing soil water in 0-20 cm layer. These results suggested that C. korshinskii and A. ordosica changed their water use strategy after large rainfall events, which might enable them to more easily adapt to arid environment.