Quadratic Regression Curves Research Articles

Determining the constant diffusion coefficient by Fourier series solution of the diffusion equation

The purpose of this study was to obtain the diffusion coefficient by calculating directly from the Fourier series solution of the diffusion equation, which has not been studied so far. The Fourier series solution is the sum of a steady-state solution and a transient solution. The steady-state solution is a linear function of distance. The transient solution is the product of a distance function and a time function. The Fourier sine series solution, a function of distance only, is negative for the steady-state solution. For the sublimation diffusion of disperse dye in paste into polyethylene terephthalate (PET) film using the film-roll method, the constant surface concentration and the diffusion distance were determined from the quadratic regression curve for the concentration distribution at a long time. The concentration distribution of the transient solution is a downwardly convex curve with negative values. The concentration distribution of the Fourier series solution is also a downwardly convex curve. The diffusion coefficient in the exponential term, a function of time only, was determined from the value of the exponential term obtained by the surface concentration and the diffusion distance. The constant diffusion coefficients determined from the Fourier series solution are reliable because they are very similar to those obtained from the error function solution and have excellent linearity of the linear regression lines for their Arrhenius plots.

Comparison of formulas derived from Fourier series solution of diffusion equation

The first Fourier series solution satisfying the boundary condition of zero concentration at the diffusion distance was derived by assuming that the solution consists of a steady-state solution and a transient solution. The first total amount which has passed through the first layer surface was derived from the first Fourier series solution. When the diffusion distance is large, the exponential term in the first total amount cannot be zero. For the sublimation diffusion of disperse dye in paste into polyethylene terephthalate film using the film-roll method, the plot of the first total amount against time was in good agreement with the quadratic regression curve. The second Fourier series solution satisfying the boundary condition of constant concentration at the diffusion distance was derived by assuming that the diffusion distance is the thickness of the first layer. The second total amount which has passed through the second layer surface was derived from the second Fourier series solution and is a linear function of time because the exponential term is zero due to the very small diffusion distance, the thickness of the first layer. The plot of the second total amount against time was in good agreement with the linear regression line. The time-lag formula was derived from the second total amount. The diffusion coefficients determined from the second total amount are much larger than those of the other three types. All four types showed excellent linearity in Arrhenius plot, but the activation energy for the time-lag formula is somewhat greater than the rest.

Taurine prevented the decline of fillet quality and muscle antioxidant capacity in on-growing grass carp (Ctenopharyngodon idella) fed non-fishmeal diet

Taurine is abundantly present in fishmeal, while plant protein sources typically contain minimal to no taurine. This disparity in taurine content may explain variations in fish quality traits caused by the dietary substitution of fishmeal with plant protein sources. This research explored whether taurine supplementation to non-fishmeal (NFM) diet could improve fillet quality and muscle antioxidant capacity in grass carp. A total of 540 fish (255.74 ± 0.65 g) were distributed among six groups. One of them was provided with a fishmeal (FM) diet, while the remaining five groups received NFM diets, formulated with incremental concentrations of crystalline taurine (0, 0.5, 1.0, 1.5, 2.0 g/kg) for 60 days. Our data showed that, in comparison with the un-supplemented group, the optimal taurine supplementation to NFM diet yielded the following findings: (1) increased fillet nutritional values by improving crude protein content, free amino acid and fatty acid compositions; (2) improved fillet physicochemical properties by improving water holding capacity (WHC), tenderness, and preventing pH decline; (3) enhanced antioxidant enzymes activities and gene expressions through nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathway. Additionally, this optimal NFM diet showed to be competitive with FM diet in terms of fillet quality. According to quadratic regression curves of ROS production and polyunsaturated fatty acids (PUFA) content, the optimal taurine supplementation levels in NFM diet for on-growing grass carp were 1.12 and 1.18 g/kg diet, respectively.

Towards hand grip force assessment by using EMG estimators

The purpose of this study was to propose a method to assess individual regression (calibration) curves to establish a relationship between an isometric grip force and surface electromyography (EMG) estimator. In this study 18 healthy volunteers (12 male (23.0 ± 2.0 years) and 6 female (23.2 ± 0.7 years)) had been examined. Ten EMG estimators (mean absolute value, root mean square, entropy, energy, turns per second, mean of zero crossings, median power frequency, mean power frequency, and Hilbert transforms), two EMG locations (brachioradialis and flexor digitorum superficialis) and five types of regression curves (linear, exponential, power, logarithm, and quadratic polynomial) have been tested. Using a quadratic polynomial regression curve and energy EMG estimator of the flexor digitorum superficialis muscle, it was obtained the lowest dispersity of EMG estimator and the most accurate prediction of grip isometric force among all tested EMG estimators.

Developmental Changes in Stroop Task Performance among Individuals with High-Functioning Pervasive Developmental Disorders.

This study aimed to assess age-related changes in Stroop Color and Word test indices in individuals with high-functioning pervasive developmental disorder (HF-PDD) and compare their performance with typically developing (TD) individuals. There were a total of 125 participants (57 TD, 68 HF-PDD), aged 6-24. Stimuli were displayed on computer screens, and participants verbally responded with response times recorded via voice key function. Single regression analysis revealed age-associated trends in Stroop test indices for both groups, indicating shorter response times and reduced Stroop interference with age. The age at which the best Stroop test results were obtained ranged from 220 to 260 months for TD and from 195 to 201 months for HF-PDD. While color naming and word reading tasks showed no significant group differences, color word naming task response times were significantly longer for the HF-PDD group. Around 30% of HF-PDD participants scored over two standard deviations above the TD mean. Both TD and HF-PDD groups exhibited age-related changes in Stroop task performance, which were fitted by a quadratic regression curve. Prolongation of the color word naming task in the HF-PDD group suggests that approximately 30% of individuals with HF-PDD have difficulty with stereotype suppression. J. Med. Invest. 71 : 254-259, August, 2024.

Experimental Study on Sleep Quality in Naturally Ventilated Rooms under Moderate Climate Conditions

Optimizing the thermal environment of a bedroom is desirable for good sleep. In moderate climatic conditions, natural ventilation is a viable method for enhancing the quality of sleep by improving indoor air conditions. This study examined the effects of air temperature and wind speed on sleep quality in naturally ventilated rooms with windows open and closed, during autumn. Thirteen young males in healthy conditions participated in this study. Two adjacent test rooms (for opened and closed conditions) were selected on a university campus, with standardized indoor conditions. Air temperature and wind speed were measured near the height of the participants’ heads. Sleep efficiency and wake after sleep onset (WASO) were calculated using physiological wearable sensors based on heart rate and body movement. The participants completed questionnaires on thermal sensation and comfort before and after sleep. The results showed that the lowest percentage of WASO was observed when the nocturnal mean temperature was 23–24°C with a quadratic regression curve regardless of the window opening conditions. Conversely, subjective sleep satisfaction and WASO did not show any significant differences between the conditions. The results revealed no significant impact of varying thermal and airflow conditions during autumn on thermal/airflow comfort, although significant differences were observed in the thermal/airflow sensation before and after sleep. Thus, these results suggest that natural ventilation through the opening of windows might not affect thermal/airflow comfort, while a nocturnal indoor air temperature of 23–24°C is recommended for good sleep and thermal comfort, regardless of window opening conditions under moderate climate conditions.

Dietary arginine levels affect growth performance, intestinal antioxidant capacity and immune responses in largemouth bass (Micropterus salmoides)

This study explored the role of dietary arginine level (DAL) on growth, intestinal antioxidant status and immune response in juvenile largemouth bass (Micropterus salmoides), providing guidance for the optimization of commercial feed in largemouth bass. Six graded arginine levels in diets were fed to the fish for 8 weeks (1.96%, 2.28%, 2.52%, 2.81%, 3.09% and 3.35% diets). The findings were as follows: with increasing DALs, FW, WG and SGR increased first and decreased, and FCR showed the opposite trend. There was no difference in the contents of crude protein and ash among graded DAL (P > 0.05). DAL (3.09% and 3.35%) significantly increased the activities of plasma AST (P < 0.05). Certain range of dietary arginine levels could improve antioxidant ability by regulating intestinal antioxidant-related parameters including the activities of SOD, GPx, and the contents of GSH and MDA. The gene expression of Nrf2 was significantly increased in response to 2.52% DAL, while Keap1 expression was decreased (P < 0.05). Furthermore, 1.96% and 2.28% DALs significantly increased the gene expression of CAT and GPx (P < 0.05), and SOD expression was the highest in response to 2.52% and 2.81% DALs (P < 0.05). Compared with the control group, the relative expressions of IL-1β, IL-8, TNF-α and NF-κB were reduced that were fed 2.52%− 3.35% DALs. Moreover, the relative expression of IL-10 and TGF-β were peaked in response to 2.81% DAL (P < 0.05). The quadratic regression curve analysis according to the growth results of SGR and FCR, the expressions of IL-10 and TGF-β showed that the optimal dietary arginine requirement for largemouth bass were 2.40%− 2.63% (5.03%−5.46% of dietary protein), and could promote growth, intestinal antioxidant capacity and immune responses in juvenile largemouth bass.

Effects of thickness and polishing treatment on the translucency and opalescence of six dental CAD-CAM monolithic restorative materials: an in vitro study

BackgroundComputer-aided design and computer-aided manufacturing (CAD-CAM) materials for prosthetic is gaining popularity in dentistry. However, limited information exists regarding the impact of thickness and roughening treatment on the optical properties of contemporary CAD-CAM restorative materials. This study aimed to quantitatively evaluate the translucency and opalescence of six dental CAD-CAM materials in response to different thicknesses and roughening treatments.MethodsSix dental CAD-CAM materials, lithium disilicate glass–ceramic (IPS e.max CAD, LS), polymer-infiltrated ceramic (VITA Enamic, VE), resin-nano ceramic glass–ceramic (LAVA Ultimate, LU), polymethyl methacrylate (Telio CAD, TE), and two zirconia reinforced lithium silicate (VITA Suprinity, VS, and Celtra Duo, CD), in shade A2 were prepared as 12 × 12mm2 specimens of four thicknesses (0.5mm, 1.0mm, 1.5mm, and 2.0mm) (N = 240, n = 10). After three different treatments (polished, roughened by SiC P800-grit, and SiC P300-grit), the translucency parameter (TP00) and opalescence parameter (OP) were measured with a spectrophotometer (VITA Easyshade V). The surface roughness was analyzed with a shape measurement laser microscope. The data were analyzed using a MANOVA, post hoc Tukey–Kramer test, the t test, and regression analysis (α = .05).ResultsThe TP00 and OP were significantly influenced by material type, thickness and roughening treatment (P < .05). TP00 showed a continues decline with increasing thicknesses, while the variations of OP were material-dependent. TP00 ranged from 37.80 (LS in 0.5mm) to 5.66 (VS in 2.0mm), and OP ranged from 5.66 (LU in 0.5mm) to 9.55 (VS in 0.5mm). The variations in TP00 of all materials between adjacent thicknesses ranged from 2.10 to 15.29, exceeding the acceptable translucency threshold except for LU. Quadratic and logarithmic regression curves exhibited the best fit for TP00 among the materials. Compared to polished specimens, rougher specimens exhibited lower TP00 and higher OP in all materials except for LS (P < 0.05). Roughening with P300-grit decreased TP00 and OP by an average of 2.59 and 0.43 for 0.5mm specimens, and 1.26 and 0.25 for 2.0mm specimens, respectively.ConclusionsVariations in translucency caused by thickness and roughening treatment were perceptible and may be clinically unacceptable. Careful consideration should be given to the selection of CAD-CAM materials based on their distinct optical properties.

Impact of magnetic resonance imaging-related geometric distortion of dose distribution in fractionated stereotactic radiotherapy in patients with brain metastases.

The geometric distortion related to magnetic resonance (MR) imaging in adiagnostic radiology (MRDR) and radiotherapy (MRRT) setup is evaluated, and the dosimetric impact of MR distortion on fractionated stereotactic radiotherapy (FSRT) in patients with brain metastases is simulated. An anthropomorphic skull phantom was scanned using a1.5‑T MR scanner, and the magnitude of MR distortion was calculated with (MRDR-DC and MRRT-DC) and without (MRDR-nDC and MRRT-nDC) distortion-correction algorithms. Automated noncoplanar volumetric modulated arc therapy (HyperArc, HA; Varian Medical Systems, Palo Alto, CA, USA) plans were generated for 53patients with 186 brain metastases. The MR distortion at each gross tumor volume (GTV) was calculated using the distance between the center of the GTV and the MR image isocenter (MIC) and the quadratic regression curve derived from the phantom study (MRRT-DC and MRRT-nDC). Subsequently, the radiation isocenter of the HA plans was shifted according to the MR distortion at each GTV (HADC and HAnDC). The median MR distortions were approximately 0.1 mm when the distance from the MIC was < 30 mm, whereas the median distortion varied widely when the distance was > 60 mm (0.23, 0.47, 0.37, and 0.57 mm in MRDR-DC, MRDR-nDC, MRRT-DC, and MRRT-nDC, respectively). The dose to the 98% of the GTV volume (D98%) decreased as the distance from the MIC increased. In the HADC plans, the relative dose difference of D98% was less than 5% when the GTV was located within 70 mm from the MIC, whereas the underdose of GTV exceeded 5% when it was 48 mm (-26.5% at maximum) away from the MIC in the HAnDC plans. Use of adistortion-correction algorithm in the studied MR diagnoses is essential, and the dosimetric impact of MR distortion is not negligible, particularly for tumors located far away from the MIC.

Determination of constant diffusion coefficient for error function solution of diffusion equation using film-roll method

The error function solution of the diffusion equation with the constant surface concentration was derived by the heat kernel to determine the constant diffusion coefficient for diffusion satisfying the infinite dye-bath condition. For the sublimation diffusion of disperse dye in paste into PET film using the film-roll method, the constant surface concentration was determined from the concentration distribution, and the diffusion coefficients of each layer were obtained by the constant surface concentration from the error function solution. When comparing the diffusion coefficients between the layers and comparing the mean diffusion coefficients for different times at a specific temperature, the constant surface concentrations determined from the quadratic regression curves for concentration–distance plots were more appropriate than those determined from the steady-state concentration distributions, which was also confirmed by the plots of concentrations obtained from the error function solution. At a specific temperature, the average of the mean diffusion coefficients obtained by the constant surface concentration of the quadratic regression curve at three specific times matched well with the constant total-amount diffusion coefficient obtained by the slope of the linear regression line for the plot of total amount against square root of time, which was confirmed by their Arrhenius plots.

Effects of dietary vitamin E on the growth performance, immunity and digestion of Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂ by physiology, pathology and RNA-seq

Vitamin E (VE) is an essential nutrient for most animals. Investigating the requirement and effects of vitamin E for Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂ would be meaningful. In the study, a 12-week feeding trial was conducted via the juvenile fish (initial body weight: 20.48 ± 0.20 g), and the physiological and biochemical indexes detection, histology observation and transcriptome analysis were operated to reach our goals. The results showed that vitamin E deficiency would result in bad effects on the growth, immunity and digestion, and induced some injury for the tissues. The analyse of quadratic regression curve and broken-line regression curve for some representative parameters revealed the optimal dosage of dietary VE for the fish was at 130.12–156.52 mg/kg. Comparative transcriptomic analyses revealed that VE mainly regulated the inflammatory response related genes(IL-1β, Irak3, Irak4, Nfkbia), immune related genes (Cd40, Fos, Cxcl9, Ccl20, Cxcr, Tnfaip3, Akt, Calca), membrane stability genes (Fgf1, Mrl and Gadd45b) and metabolism related genes (Gck and Ins) to influence the liver function and for the foregut, the functional metabolism related genes were Try3, Prss2, Cel, Pla2g1b, Ins Socs3 and Sqle and the Socs3 maybe also an important function gene in maintaining a good status of the foregut. Our study provided a new insight of VE function on the fish, meanwhile, it enriched the bioinformatic data of this species, as well as contributed to the healthy culture of the fish.

Dietary supplementation with fermented antarctic krill shell improved the growth performance, digestive and antioxidant capability of Macrobrachium nipponense

To investigate the effects of different levels of fermented antarctic krill shell (FAKS) on the growth performance, hemolymph biochemistry, hepatopancreatic antioxidant capacity, and digestive enzyme activities of Macrobrachium nipponense, five isonitrogenous and isoenergetic experimental diets containing different proportions of FAKS (0 %, 0.25 %, 0.5 %, 1.0 %, 2.0 %) were fed to M. nipponense for 8 weeks. The results showed the weight gain rate (WGR), specific growth rate (SGR), head-to-body ratio (H/S), and head-to-tail ratio (H/T) increased first and then decreased with higher proportions of FAKS. The FAKS1.0 group exhibited the highest values, and significantly higher than that of the FAKS0 group (P < 0.05). Compared with the control group, FAKS inclusion could increase the concentration of hemolymph albumin (ALB), and reduce the concentration of alkaline phosphatase (ALP) (P < 0.05). The concentration of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly lower in the FAKS1.0 group (P < 0.05). The hepatopancreas trypsin (TPS) concentration in the FAKS1.0 group, and the lipoprotein lipase (LPL) concentration in the FAKS0.25, FAKS0.5 and FAKS1.0 groups were significantly higher than that in other groups respectively (P < 0.05). With increasing proportions of FAKS, the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and ceruloplasmin (CP) in the hepatopancreas tended to increase and then decrease, and were significantly higher in the FAKS0.5 group than that in the FAKS0 group (P < 0.05). The concentration of malondialdehyde (MDA) in the FAKS0.25, FAKS0.5 and FAKS1.0 groups was significantly lower than that in the FAKS0 group (P < 0.05). In conclusion, adding a certain level of FAKS to the feed significantly improved the growth performance, digestive enzyme, and antioxidant enzyme activity of M. nipponense. Based on the quadratic regression curve fitting, the optimal WGR and SGR can be achieved when the proportion of dietary FAKS is 1.140 % and 1.149 %, respectively.

Towards mitigating the effect of plasma bubbles on GPS positioning accuracy through wavelet transformation over Southeast Asian region

Ionospheric irregularities remain as a challenging concern among space scientists and engineers as it can pose severe threats to satellite-based services by introducing amplitude and phase scintillations in the transionospheric radio signals. The scintillations may cause degradation of the positioning, navigation, and timing (PNT) services or even complete system failure under extreme conditions. The present work focuses on understanding the ionospheric irregularities during the space weather event on May 12, 2021, witnessing the first strong geomagnetic storm in the 25th solar cycle. This particular event commenced around 13.00 UT, apparently altering the regular development of equatorial plasma bubbles around the local post-sunset terminator. We selected three global positioning system (GPS) stations, one at the near-magnetic equator (CUSV) and two at far low-latitude locations with a longitudinal separation (THKK and HWKS) over the Southeast Asian longitudes to investigate the characteristics of ionospheric plasma irregularities on the storm day. The results showed that the amplitude of ROTI was highest at the low-latitude CUSV, followed by the THKK and HKWS stations. The increased ROTI at CUSV is due to its latitudinal location close to the geomagnetic equator in the equatorial ionization anomaly (EIA) region which often witnesses more fluctuations than the inter-mediate latitudes. The strong TEC fluctuation occurrences were comparatively minimal at HWKS station on the storm day (May 12, 2021), whereas both intermediate and relatively higher TEC fluctuation occurrences were found at THKK and CUSV stations, respectively. Moreover, the occurrence rate of moderate irregularities was the highest at CUSV, followed by THKK and HKWS, while that of weak irregularities was maximum at HKWS, followed by THKK and CUSV. This happens because the systematic longitudinal time delay observed at the onset of ionospheric scintillations corresponds to the rise of PBs velocity at the magnetic equator that strongly depended upon the F-region dynamo electric fields in the east–west direction. Furthermore, the three-dimensional (3-D) positioning errors were estimated at a 30-sec interval to understand the impact of storm-induced irregularity on the positioning solution. An excellent agreement is realized between the ROTI pattern and positioning errors at all stations, irrespective of latitudinal extent from the magnetic equator. In order to model the amplitude of the scintillation index against the SNR measurements, the linear, quadratic, and cubic regression curve fittings are utilized that indicate the cubic polynomial manifesting the best fitted SNR measurements with the weak as well as moderate scintillation index. The continuous wavelet transformation (CWT) method was implemented to mitigate the ionospheric scintillation effects on positioning accuracy. The CWT estimation reveals the hidden information in positioning error due to the scintillation index, which makes it easy to understand the ionospheric scintillation effects on positioning. The attempt in this work is aligned with the efforts towards reliable PNT operations over equatorial and low latitudes.

Oxygen Uptake Efficiency Slope in South American Healthy Adults: COMPREHENSIVE REFERENCE VALUES AND INTERNATIONAL COMPARISONS.

The purpose of this study is to provide comprehensive reference values for oxygen uptake efficiency slope (OUES) in healthy adults. International heterogeneity was also explored through published databases. A cross-sectional study was conducted with treadmill cardiopulmonary exercise testing (CPX) from a Brazilian healthy adult sample, in which absolute OUES and values normalized by weight and body surface area (BSA) were calculated. Data were stratified by sex and age group. Prediction equations were calculated using age and anthropometric variables. International data were pooled and differences were explored using factorial analysis of variance or the t test, as appropriate. The OUES age-related patterns were calculated using regression analysis. A total of 3544 CPX were included (1970 males and 1574 females) and the age ranged from 20-80 yr. Males had higher values than females for OUES, OUES/kg, and OUES/BSA. Lower values were found with aging and the data followed a quadratic regression curve. Reference value tables and predictive equations were provided for absolute and normalized OUES in both sexes. International comparisons of absolute OUES values among Brazilian, European, and Japanese data revealed substantial heterogeneity. The OUES/BSA measure minimized the discrepancies between Brazilian and European data. Our study provided comprehensive OUES reference values in a large healthy adult sample from South America with a wide age range and included absolute and normalized values. Differences observed between Brazilian and European data were reduced in the BSA-normalized OUES.

Research on Rock Crack Classification Based on Acoustic Emission Waveform Feature Extraction Technology

Abstract Rock fracture mode has practical significance for the prediction and prevention of engineering disasters, and the inversion of fracture mode by the waveform signal not only reduces the experimental error of the mechanical strength measurement but also simplifies the type and quantity of disaster prediction source data. For the relationship between crack mode and mechanical strength, the acoustic emission (AE) waveform signal is studied. Six coarse-grained sandstone samples were tested by uniaxial compression, AE, and scanning electron microscopy. The results show that the number of microhole cracks in rock is positively correlated with tensile-shear cracks and negatively correlated with mechanical strength. The quadratic function regression curve of the proportion of shear cracks and mechanical strength is more realistic. When crack ratio is less than 0.31, the number of shear cracks is positively correlated with the mechanical strength and vice versa. The waveform mutation coefficient k is defined as the overall change description. It is found that the increase of signal mutation has a positive impact on the mechanical strength of rock. The fitting function of crack and the signal mutation near the peak of rock can be divided into six risk zones in a two-dimensional plane. In addition to these exciting results and discoveries, the determination of the number of tensile-shear cracks and its relationship with mechanical strength provide innovative methods and ideas for crack pattern discrimination and rock burst risk assessment of roadway surrounding rock.

Effect of nitrogen topdressing on planting density response of grain yield in maize with different planting pattern cultivation

AbstractWe investigated the maize grain yield in response to nitrogen topdressing at different planting densities and planting patterns (twin row, TR; narrow row, NR; and conventional row, CR) over 3 years using early‐maturing cultivars. The P8025 grain yield was higher with a nitrogen topdressing of 6 g/m2 (N6) than without a nitrogen topdressing (N0) at all planting densities in 2017, 2018, and 2019. The difference between the nitrogen topdressing treatments was largest at a planting density close to 10 plants per square meter, which resulted in the highest grain yield in the N0 plot. The rank order for the grain yields among planting patterns was TR ≥ NR &gt; CR in the three analyzed years. Changes in grain yield associated with planting densities followed significant negative quadratic regression curves for all planting patterns. In both the N0 and N6 plots, the grain yield response to planting density was more stable for TR cultivation than for CR and NR cultivation. The rank order for the nitrogen use efficiency (NUE) among planting patterns was TR ≥ NR ≥ CR. The differences in the NUE among planting patterns were higher at higher planting densities. The high NUE observed for TR and NR cultivation was due to the high topdressed nitrogen absorption rate (Nab) at a planting density less than 8.9 plants per square meter as well as the efficiency of the grain yield increase resulting from absorbed nitrogen (Ngy) at a planting density greater than 10.3 plants per square meter. The higher NUE for TR cultivation than for NR cultivation at 12.1 plants per square meter was because of a difference in Ngy and was unrelated to Nab. These results suggest that the improvement of planting pattern (TR, NR) can enhance the effect of topdressed nitrogen on grain yield in maize due to the increase of Nab or Ngy according to the planting density.

Fault Diagnosis of Rotor Broken Bar in Induction Motor Based on Successive Variational Mode Decomposition

When an induction motor is running at stable speed and low slip, the fault signal of the induction motor’s broken bar faults are easily submerged by the power frequency (50 Hz) signal. Thus, it is difficult to extract fault characteristics. The left-side harmonic component representing the fault characteristics can be distinguished from power frequency owing to V-shaped trajectory of the fault component in time-frequency (t-f) domain during motor startup. This article proposed a scheme to detect broken bar faults and discriminate the severity of faults under starting conditions. In this scheme, successive variable mode decomposition (SVMD) is applied to analyze the stator starting current to extract the fault component, and the signal reconstruction is proposed to maximize the energy of the fault component. Then, the quadratic regression curve method of instantaneous frequency square value of the fault component is utilized to discriminate whether the fault occurs. In addition, according to the feature that the energy of the fault component increases with the fault severity, the energy of the right part of the fault component is proposed to detect the severity of the fault. In this paper, experiments are carried out based on a 5.5 kW three-pole induction motor. The results show that the scheme proposed in this paper can diagnose the broken bar faults and determine the severity of the fault.

Analysis of Measured Parameters in Relation to the Amount of Fibre in Lightweight Red Ceramic Waste Aggregate Concrete

The present study provides a correlation and regression analysis of lightweight waste aggregate concretes with varying degrees of fibre reinforcement. The concrete mix contains pre-soaked red ceramic waste aggregate, expanded clay coarse aggregate and Portland cement. Copper-coated crimped steel fibre was used as the reinforcement. The experimental results included properties measured by destructive test methods—compressive strength, splitting tensile strength, static modulus of elasticity, the limit of proportionality, shear strength; and by non-destructive test methods—dynamic modulus of elasticity and surface electrical resistivity. These properties were analysed to study the relevancy and significance between non-destructive and destructive methods of measurement in the case of different amounts of fibre. The results show differences in the degree of fit to the linear and quadratic regression curves for pairs of destructive and non-destructive test results. As expected, the linear relationship can be applied in a few cases, but the quadratic curve must be used for a few pairs. Another observation is that it is not possible to neglect the amount of fibre in the correlation analyses of the measured properties.

Normal aging changes in the choroidal angioarchitecture of the macula

The choroidal vascularity index (CVI) has been shown to be sensitive in detecting changes in choroidal angioarchitecture in a range of ocular diseases. However, changes in CVI in association with normal physiological aging and spatial distribution remains to be determined. This is significant as a range of ocular conditions with choroidal degeneration are associated with aging. In this study, we assessed CVI for 106 healthy eyes from 106 individuals (range 21–78 years old, ~ 20 individuals/decade) at 15 eccentricities across the macula (0, 230 µm, 460 µm, 690 µm, 1,150 µm, 1,380 µm and 2,760 µm from the fovea in the superior and inferior direction). Total choroidal area, luminal area and stromal area were all significantly decreased with age (p < 0.001 for all parameters). CVI was also significantly decreased with age (p < 0.01) and eccentricity. Fitting of quadratic regression curves to CVI as a function of age yielded a good fit for all eccentricities (r2 = 0.55–0.80) and suggested a decrease in CVI from the ages of 33–43 years at a rate of 0.7–2.7% per decade. CVI was lower in the inferior versus superior retina at matching eccentricities and a significant difference in age-related decline of CVI with eccentricity only occurred in inferior locations. These findings suggest choroidal angioarchitecture declines from the 4th decade of life with potential eccentricity differences in the inferior and superior retina. Considering the number of age-related diseases with choroidal dysfunction, these results provide foundational knowledge to understand choroidal involvement in these diseases.

PROCESSING TECHNOLOGY AND PACKAGING MATERIALS EFFECTS ON ACCEPTABILITY, STORAGE STABILITY AND SHELF LIFE OF “AADUN” (NIGERIAN MAIZE BASED SNACKS)

“Aadun” is a Nigerian traditional maize based snack, but now poorly accepted by todays snack consumers despites its quality. To increase acceptability sensory panelist using 5 points ranking scores were asked to rank “Aadun” processed using laboratory equipment and traditional processed commercial samples purchased from Ibadan and Abeokuta with packaging materials of Leaf (Taumatoccous Danielle), Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Aluminum foil (ALF) and Polystyrene plastic cup (PSC). Laboratory “aadun” packaged in different materials and the commercial samples packaged in LDPE were stored under refrigeration (4-5 0C; RH 74.85%), ambient (25-30 0C; RH 66.7%) and sunlight (30-44 0C; RH 65.81%) conditions for 6 months and at 2 weeks intervals off flavor (OF) was determined by 10 trained sensory panelists and growth of microorganism by total plate count (TPC) method. Shelf life was estimated by plotting hazard (TPC) against time on linear and quadratic regression curve and safety cut off value of 105cfu/g as limit. Results showed the highly ranked “Aadun” was Laboratory sample followed by Ibadan and Abeokuta samples and PSC ranked highest followed by ALF, HDPE, LDPE and Leaf. A longer lag period before OF and TPC increased was under Refrigeration, PSC, LDPE Laboratory and Abeokuta samples but, shorter under ambient, sunlight, leaf and LDPE Ibadan sample. Longer shelf life period was under refrigeration, PSC (42.4 weeks), LDPE laboratory (40.1 weeks), LDPE Abeokuta (33.2 weeks but shorter under ambient, sunlight, leaf (19 weeks) and LDPE Ibadan (30.5 weeks). This study shows that if modern technology and PSC packing plastic materials and storing under refrigeration conditions will improve acceptability, long storage stability and shelf life thereby, increasing production and the economy of the local women processor in Nigeria.