Deviation Of Curve Research Articles

Performance evaluation of 4-stroke gasoline engine using Bio fuel (Ethanol)

The article examines the performance of a 4-stroke gasoline engine using Bio-fuel (Ethanol). The research work was carried out on a SOLTEQ engine test bed available in university in Thermodynamics laboratory. In this study an ordinary gasoline engine was fixed on test bed. Several modifications to external parts of the engine were made to fix it on the bed such as base frame, suction port, exhaust port and oil temperature indicators. To asses engine performance the experiment setting used gasoline with 5 different blends of ethanol such as E0 (100% gasoline), E5 (95% gasoline, 5% ethanol), E10 (90% gasoline, 10% ethanol), E15 (85% gasoline, 15% ethanol) and E20 (80% gasoline, 20% ethanol). While the engine performance was evaluated at operating parameter called wide open throttle (WOT). Different charts were established to compare results. The results obtained from analysis showed significant deviations in performance curves at different fuel grades. These results were quite useful especially for utilizing ethanol additives with gasoline in ordinary gasoline engines.

Long Periods of Increased/Decreased Runoffs of Large Russian Rivers

Long series of annual and seasonal runoffs of large Russian rivers (the Volga at Volgograd, the Don at Razdorskaya, the Yenisei at Igarka, and the Lena at Kyusyur) since the 1870s for the Russian Plain rivers and since the 1930s for the Siberian rivers have been analyzed. Long periods (phases) of increased and decreased water flow have been identified. The boundaries of contrast phases are determined with cumulative deviation curves in combination with Student’s test. The duration of the phases varies from 20–25 years to many decades (for runoff in low-water seasons of the Volga and Don). For the Volga and Don, the phases of decreased runoff are generally longer than increased flow phases (this is especially true for low-water seasons). The identified contrast phases show a statistically significant difference between the annual and seasonal runoffs, which varies from 10 to 65%. In the phases of increased flow, high-water years occur much more often than low-water years, and vice versa. In the period of current climate warming (since 1981), the changes in annual runoff relative to the calculated runoff of the reference period (from the 1930s to 1980) are opposing, i.e., the runoff decreased in the Don and increased in the Volga, Yenisei, and Lena. In this case, the changes are most significant in the Don. In the period of current climate warming, both the winter and snow-melt flood runoff has increased only for the Lena. At the same time, the contributions of climatic and anthropogenic factors to the changes in runoff differ significantly for each of the rivers under study.

Ultrafast Dynamics and Ultrasensitive Single-Particle Intermittency in Small-Sized Toxic Metal Free InP-Based Core/Alloy-Shell/Shell Quantum Dots: Excitation Wavelength Dependency Toward Variation of PLQY

Observation of strong deviation of photoluminescence excitation curve from absorption curve especially at lower wavelength range, below 450 nm in case of small-sized toxic metal free InP-based core...

Regiospecific Analysis of Triacylglycerols by Ultrahigh-Performance-Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry.

An ultrahigh-performance-liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method was developed for the analysis of AAB and ABC type triacylglycerol (TG) regioisomers. Excellent linear regressions were established between the ratio of [RR]+ product ions and the proportion of regioisomers of TGs. The method was further optimized by analysis of 18 regiospecific pairs of AAB type TGs and five triplets of regioisomers of ABC type TGs with acyl carbon number (ACN) ranging from 36 to 54 and the number of double bonds (DB) from 0 to 7. Reverse linear relationships were recognized between the slope of the calibration curve and the number of double bonds of the sn-2 fatty acids. Negative linear regressions were found between the intercepts of the calibration curves and the sum of ACN + DB of sn-2 fatty acids. The method was highly repeatable as shown by the low deviation and high stability of the calibration curves at different concentrations and between different periods of analysis. This is the first time that calibration curves for the ABC type TGs are reported. The results provide crucial and novel information for reliable and quantitative determination of regioisomeric TGs in natural fats and oils.

Fetal Growth Restriction.

Fetal growth restriction (FGR) is a failure of fetus to reach its expected biological growth, based on its genetically predetermined potential. Whenever effective fetal weight is less than, 10th percentile or 2 standard deviation of population-specific growth curve, it is considered small for gestational age (SGA). The FGR is associated with poor somatic growth with concomitant changes in placental and cerebral blood flow and/or biochemical markers along with EBW < 3rd percentile. It is an important cause of perinatal mortalities and morbidities. Ultrasound plays a definitive role in diagnosis and its management. This article is aimed to mini review the published guidelines on FGR and SGA and summarize the areas of consensus.

Phase-curve analysis of comet 67P/Churyumov-Gerasimenko at small phase angles

Aims. The Rosetta-OSIRIS images acquired at small phase angles in three wavelengths during the fly-by of the spacecraft on 9–10 April 2016 provided a unique opportunity to study the opposition effect on the surface of comet 67P/Churyumov-Gerasimenko (67P). Our goal is to study phase curves of the nucleus at small phase angles for a variety of surface structures to show the differences in their opposition effect and to determine which surface properties cause the differences. Methods. We used OSIRIS NAC images that cover the Ash-Khepry-Imhotep region to extract the phase curve, that is, the reflectance of the surface as a function of phase angle. We selected six regions of interest (ROIs) and derived the phase curves for each ROI. We fit a linear-exponential function to the phase curves. The resulting model parameters were then interpreted by spectrophotometric, geomorphological, and phase-ratio analyses, and by investigating the influence of structural and textural properties of the surface. Results. We find evidence for the opposition effect (deviation of the phase curve from linear behavior) in phase curves for all areas. We found an anticorrelation between the phase ratio and reflectance in a small phase angle range. This provides evidence for the shadow-hiding effect. We conclude that the decrease in the slope of the phase ratio versus reflectance indicates a decrease in the proportion of shadowed regions and reduces the contribution of the shadow-hiding effect. Large uncertainties in the determination of the opposition effect parameters with respect to wavelength do not allow us to conclusively claim coherent backscattering in the opposition effect phenomenon. Based on the two analyses, we conclude that the opposition effect of comet 67P in the Ash-Khepry-Imhotep region is mainly affected by shadow-hiding.

Optimization of Corner Blending Curves

The blending or filleting of sharp corners is a common requirement in geometric design applications — motivated by aesthetic, ergonomic, kinematic, or mechanical stress considerations. Corner blending curves are usually required to exhibit a specified order of geometric continuity with the segments they connect, and to satisfy specific constraints on their curvature profiles and the extremum deviation from the original corner. The free parameters of polynomial corner curves of degree ≤6 and continuity up to G3 are exploited to solve a convex optimization problem, that minimizes a weighted sum of dimensionless measures of the mid-point curvature, maximum deviation, and the uniformity of parametric speed. It is found that large mid-point curvature weights result in undesirable bimodal curvature profiles, but emphasizing the parametric speed uniformity typically yields good corner shapes (since the curvature is strongly dependent upon parametric speed variation). A constrained optimization problem, wherein a particular value of the corner curve deviation is specified, is also addressed. Finally, the shape of Pythagorean-hodograph corner curves is compared with that of the optimized “ordinary” polynomial corner curves.

GENERALIZED PARETO DISTRIBUTION BASED ON GENERALIZED ORDER STATISTICS AND ASSOCIATED INFERENCE

Abstract In this paper, we have considered the generalized Pareto distribution. Various structural properties of the distribution are derived including (quantile function, explicit expressions for moments, mean deviation, Bonferroni and Lorenz curves and Renyi entropy). We have provided simple explicit expressions and recurrence relations for single and product moments of generalized order statistics from the generalized Pareto distribution. The method of maximum likelihood is adopted for estimating the model parameters. For different parameter settings and sample sizes, the simulation studies are performed and compared to the performance of the generalized Pareto distribution.

PET image denoising using unsupervised deep learning.

Image quality of positron emission tomography (PET) is limited by various physical degradation factors. Our study aims to perform PET image denoising by utilizing prior information from the same patient. The proposed method is based on unsupervised deep learning, where no training pairs are needed. In this method, the prior high-quality image from the patient was employed as the network input and the noisy PET image itself was treated as the training label. Constrained by the network structure and the prior image input, the network was trained to learn the intrinsic structure information from the noisy image and output a restored PET image. To validate the performance of the proposed method, a computer simulation study based on the BrainWeb phantom was first performed. A 68Ga-PRGD2 PET/CT dataset containing 10 patients and a 18F-FDG PET/MR dataset containing 30 patients were later on used for clinical data evaluation. The Gaussian, non-local mean (NLM) using CT/MR image as priors, BM4D, and Deep Decoder methods were included as reference methods. The contrast-to-noise ratio (CNR) improvements were used to rank different methods based on Wilcoxon signed-rank test. For the simulation study, contrast recovery coefficient (CRC) vs. standard deviation (STD) curves showed that the proposed method achieved the best performance regarding the bias-variance tradeoff. For the clinical PET/CT dataset, the proposed method achieved the highest CNR improvement ratio (53.35% ± 21.78%), compared with the Gaussian (12.64% ± 6.15%, P= 0.002), NLM guided by CT (24.35% ± 16.30%, P= 0.002), BM4D (38.31% ± 20.26%, P= 0.002), and Deep Decoder (41.67% ± 22.28%, P= 0.002) methods. For the clinical PET/MR dataset, the CNR improvement ratio of the proposed method achieved 46.80% ± 25.23%, higher than the Gaussian (18.16% ± 10.02%, P< 0.0001), NLM guided by MR (25.36% ± 19.48%, P< 0.0001), BM4D (37.02% ± 21.38%, P< 0.0001), and Deep Decoder (30.03% ± 20.64%, P< 0.0001) methods. Restored images for all the datasets demonstrate that the proposed method can effectively smooth out the noise while recovering image details. The proposed unsupervised deep learning framework provides excellent image restoration effects, outperforming the Gaussian, NLM methods, BM4D, and Deep Decoder methods.

Abnormal Detection of Wind Turbine Operating Conditions Based on State Curves

Wind energy is a clean and renewable energy source and thus has promising future prospects. To increase the utilization rate and power generation of wind turbines and reduce their maintenance costs, it is necessary to monitor the operating conditions of wind turbines. This paper introduces a monitoring method based on state curves and includes a study that analyzes five types of state curves, namely, wind speed–power, wind speed–rotor speed, wind speed–pitch angle, rotor speed–power, and rotor speed–pitch angle. The results indicate that due to the external environment (e.g., atmospheric temperature, atmospheric pressure, wind turbulence, wind direction, topography), the wind turbine internal hardware performance, and the control strategy, the first three curves did not allow the wind turbine to distinguish the normal operation status from a fault status. However, the rotor speed–power and rotor speed–pitch angle curves were able to accurately monitor abnormal conditions of the wind turbine. This study aims to establish theoretical curves of a wind turbine and correct the state curves to calculate the distance from the actual operating point to the state curves. During operation, the wind turbine will be under several conditions, ranging from maximum power point tracking to constant speed to constant power conditions. Using the time window and a confusion matrix to determine the best deviation of the wind turbine under different operating conditions is more effective in reducing the false alarm rate. Based on the optimal offset distances and the relationship among rotor speed, power, and pitch angle during start-up and shut down, a corresponding evaluation system is established. Taking the operational data from a wind farm as an example, the research reveals that when a wind turbine is operating normally, the deviations in the state curves under different operating conditions fall within an appropriate range; once an abnormal condition occurs, if the number of abnormalities exceeds a specified value during a specified time window, then an alarm signal will sound. Compared with the supervisory control and data acquisition (SCADA) system, in this system the alarm time is advanced.

Control of construction projects using the Earned Value Method - case study

Abstract Planning, controlling, monitoring progress are key management functions for effective implementation of construction projects. Commonly used instruments enabling performance of these functions include schedules and budgets, often in the form of a cost estimate. They are created at the initial planning stage to monitor and control cost and time deviations. Moreover, popular monitoring techniques are, for example, observation of milestones and comparative analysis of actual versus planned costs. This article presents a work progress control tool - the Earned Value Method (EVM) - which, despite its benefits, remains relatively unused in construction projects. The impact of the planning phase on the results obtained during the monitoring and control phase when utilizing EVM is discussed. This case study provides practical examples of using EVM in the implementation of construction projects and with the use of computer software. The novelty of the article results from the introduction of additional sensitivity analysis illustrating the impact of factors, such as an increase in costs or a change in delivery dates to the course of deviation curves. Use of sensitivity analysis in relation to the results of the CPI and SPI calculations affords combining control of costs and time with risk monitoring in the project. The findings reveal significant benefits in using EVM to implement construction projects but also highlight some important limitations.

Noise Rejection and Detection of Partial Discharges Under Repetitive Impulse Supply Voltage

Partial discharge (PD) detection is a fundamental tool for the design and diagnosis of insulation systems, particularly organic materials that must operate throughout their life without PD. While the methods for PD measurements under sinusoidal supply voltage are well-established, the same does not hold under repetitive-pulse voltage waveforms, such as those provided by inverters. Electromagnetic noise generated by electronic switch commutation in inverters can overlap with PD pulses, making it difficult to measure, separate from noise, and identify PD. This is particularly more cumbersome when fast rise-time switches are employed. To address these issues, this paper investigates methods to detect PD pulses on enameled wires under repetitive impulsive voltages with different rise times of 60, 500, and 1000 ns, proposing techniques which allow separation of PD from noise even when they overlap in time and frequency domains. This paper employs a time-domain approach using standard deviation curve acquired from a set of measurements to discriminate PD from repetitive commutation disturbance. These techniques can be implemented to achieve unsupervised noise rejection, which would be an important goal for both offline and online PD testing. The proposed approach is validated successfully through tests carried out on a low-voltage motor.

Postural Muscle Unit Plasticity in Stroke Survivors: Altered Distribution of Gastrocnemius' Action Potentials.

Neuromuscular adaptations are well-reported in stroke survivors. The death of motor neurons and the reinnervation of residual muscle fibers by surviving motor neurons, for example, seem to explain the increased density of muscle units after stroke. It is, however, unknown whether reinnervation takes place locally or extensively within the muscle. Here we combine intramuscular and surface electromyograms (EMGs) to address this issue for medial gastrocnemius (MG); a key postural muscle. While seven stroke survivors stood upright, two intramuscular and 15 surface EMGs were recorded from the paretic and non-paretic gastrocnemius. Surface EMGs were triggered with the firing instants of motor units identified through the decomposition of both intramuscular and surface EMGs. The standard deviation of Gaussian curves fitting the root mean square amplitude distribution of surface potentials was considered to assess differences in the spatial distribution of motor unit action potentials and, thus, in the distribution of muscle units between limbs. The median number of motor units identified per subject in the paretic and non-paretic sides was, respectively, 2 (range: 1–3) and 3 (1–4). Action potentials in the paretic gastrocnemius were represented at a 33% wider skin region when compared to the non-paretic muscle (Mann-Whitney; P = 0.014). Side differences in the representation of motor unit were not associated with differences in subcutaneous thickness (skipped-Spearman r = −0.53; confidence interval for r: −1.00 to 0.63). Current results suggest stroke may lead to the enlargement of the gastrocnemius muscle units recruited during standing. The enlargement of muscle units, as assessed from the skin surface, may constitute a new marker of neuromuscular plasticity following stroke.

Calculation and Optimization of the Optimal Region Value of Integral Trapezoidal Steering

This study aims to optimize the overall mechanism size of trapezoidal steering. A mathematical model is established and optimized in combination with its working characteristics. The objective function is the objective function of the actual momentary position of the vehicle and the error of Ackermann's instantaneous position, so that the actual instantaneous position in the theoretical instantaneous position near the maximum fluctuations in the minimum is close to the ideal Ackermann steering mechanism. Through the numerical experiment method, the instantaneous center position curve is simulated and the length of the trapezoidal pole is taken as the optimization target and the optimal area value. Results show that selecting the length of the steering mechanism in the optimal region is reasonable. The numerical experiment is compared with the theoretical mathematical model, and the optimal region is considered. The method is validated by introducing the existing calculation parameters and drawing the ideal deviation curve of the optimized steering. This study provides a normative guidance and basis for the design of trapezoidal steering mechanism.

The depth-dose curve depends on the inhomogeneity of the material irradiated by electron beam

Electron linear accelerator with average energy 9.92 ± 0.48 MeV, UELR-10-15S2, was set up and operated at the Research and Development Center for Radiation Technology, Vietnam Atomic Energy Institute, for irradiating foods and medical devices directly without X-ray converter. Inside the homogenous products, the depth-dose curve depends on electron beam energy and product density, and moreover, it also depends on the inhomogeneity of the irradiated material. In this article, the depth-dose distribution is calculated by MCNP simulation code and measured by a film dosimeter inside the inhomogeneous products. The results show that the maximum deviation of the depth-dose curve between inhomogeneous and homogeneous products with the same density is about 20%. So the area density limit for irradiating double sided on the electron beam (9.92 ± 0.48 MeV) is in the range from 6.1 to 9.7 g/cm2 instead of 8.5 g/cm2 in general.

A comparative study of potential energy curves with RKRV curves for the ground states of I2, F2 and CO molecules

The latest molecular constant potential energy curves used for the electronic ground states of I2, F2 and CO molecules are constructed by the Rydberg–Klein–Rees–Vanderslice (RKRV) method. The Morse, Rydberg, Hulbert–Hirschfelder and extended Rydberg potential functions compare each other and have good agreement with RKRV curves for these molecules. The percentage deviations from RKRV curves are drawn at the same abscissa scale. These curves show that the extended Rydberg potential energy curve deviation is \(< 0.5{-}2\%\) error to dissociation limit.

Effect of titanium substitution on the structural, magnetic and magnetocaloric properties of La0.67Ba0.25Ca0.08MnO3 perovskite manganites

We have studied the effect of Mn substitution by Ti on the structural, magnetic and magnetocaloric properties of La0.67Ba0.25Ca0.08MnTiO3 samples. All samples were synthesized using the flux method. X-ray powder diffraction showed that our samples crystallize in the rhombohedral phase $$R\overline{3} c$$ space group. According to the magnetic properties, our samples present a transition from a paramagnetic to a ferromagnetic phase upon decreasing temperature. The deviation of the inverse curve of the magnetic susceptibility from Curie–Weiss law indicates the existence of a Griffiths phase. This reveals the presence of ferromagnetic clusters in paramagnetic region. Regarding the positive slopes of Arrott’s plots, the universal theory and the Landau B(T) coefficient value sign demonstrate the second-order magnetic phase transition. The magnetic entropy change was determined based to Maxwell’s relations and Landau’s theory. Near room temperature, our samples exhibited an important magnetic entropy change with maxima of 3.21 and 2.76 J kg−1 K−1, under an applied magnetic field of 5 T, respectively, for La0.67Ba0.25Ca0.08MnO3 and La0.67Ba0.25Ca0.08Mn0.95Ti0.05O3. Relative cooling power was estimated as well. It was found to reach 168 and 187 J/kg for La0.67Ba0.25Ca0.08MnO3 and La0.67Ba0.25Ca0.08Mn0.95Ti0.05O3, respectively. From the hysteresis cycles, our studied sample showed a typical soft ferromagnetic behavior with a low coercive field at 10 K. These results make our samples promising candidates for magnetic refrigeration.

Assessing bias, precision, and agreement in method comparison studies.

Recently, a new estimation procedure has been developed to assess bias and precision of a new measurement method, relative to a reference standard. However, the author did not develop confidence bands around the bias and standard deviation curves. Therefore, the goal in this paper is to extend this methodology in several important directions. First, by developing simultaneous confidence bands for the various parameters estimated to allow formal comparisons between different measurement methods. Second, by proposing a new index of agreement. Third, by providing a series of new graphs to help the investigator to assess bias, precision, and agreement between the two measurement methods. The methodology requires repeated measurements on each individual for at least one of the two measurement methods. It works very well to estimate the differential and proportional biases, even with as few as two to three measurements by one of the two methods and only one by the other. The repeated measurements need not come from the reference standard but from either measurement methods. This is a great advantage as it may sometimes be more feasible to gather repeated measurements with the new measurement method.

Quantitative Cytologic Descriptors to Differentiate CLL, Sézary, Granular, and Villous Lymphocytes Through Image Analysis.

We aimed to find descriptors to identify chronic lymphocytic leukemia (CLL), Sézary, granular, and villous lymphocytes among normal and abnormal lymphocytes in peripheral blood. Image analysis was applied to 768 images from 15 different types of lymphoid cells and monocytes to determine four discriminant descriptors. For each descriptor, numerical scales were obtained using 627 images from 79 patients. An assessment of the four descriptors was performed using smears from 209 new patients. Cyan correlation of the nucleus identified clumped chromatin, and standard deviation of the granulometric curve of the cyan of the nucleus was specific for cerebriform chromatin. Skewness of the histogram of the u component of the cytoplasm identified cytoplasmic granulation. Hairiness showed specificity for cytoplasmic villi. In the assessment, 96% of the smears were correctly classified. The quantitative descriptors obtained through image analysis may contribute to the morphologic identification of the abnormal lymphoid cells considered in this article.

Decoupling control method of paper cross‐directional basis weight based on sparse decomposition

With a focus on the coupling problems of multivariable control for the paper cross‐directional (CD) basis weight caused by a hydraulic headbox, a novel approach of multivariable decoupling control based on sparse decomposition is proposed. The model function of the CD basis weight control for a single dilution water branch valve is used as the basis of a sparse atomic library. Then, according to the deviation curve of the CD basis weight, the particle swarm optimization (PSO) algorithm is used to obtain atoms corresponding to each control unit (the multiple dilution water branch valves) to form a sparse atomic library. As each atom in the atomic library contains the control information of the corresponding dilution water branch valve, the decoupling control of paper CD basis weight can be realized via mining control information. The essence of this method is to solve the coupling problems of multivariable control by using optimization theory. Experimental results demonstrate that this method achieves a remarkable decoupling control effect.