Minimum Coefficient Research Articles

The validity and reliability test of the leprosy life quality questionnaire in leprosy patients

Background: Leprosy is a public health problem because it potentially affects social life. In 2018, World Health Organisation (WHO) reported that Indonesia ranks third of new cases leprosy. Leprosy significantly influences patients' quality of life. Until now, there is still no specific questionnaire to assess the quality of life for leprosy patients. Leprosy Quality of Life Questionnaire (KUKUH) is a questionnaire to assess leprosy patients' quality of life, which includes questions about psychology, physical health, social environment, and treatment. The study aimed to assess the validity and reliability of the Leprosy Quality of Life Questionnaire (KUKUH) as a tool to assess the quality of life of leprosy patients in Indonesia. Methods: The study was conducted at Saiful Anwar General Hospital in Malang, East Java. The validity analysis using construct validity with a minimum correlation coefficient value considered valid by 0.3. Internal consistency assessment for the questionnaire utilized the Cronbach α value where a value greater than or equal to 0.60 is acceptable, and a value greater than or equal to 0.80 is considered good. Results: Based on the result of variable validity test, all items measuring each aspect have item correlation coefficient values with a total score (riT) > table correlation value (0.361). The results of reliability testing, the items that measure each aspect of the quality-of-life variable for leprosy patients have Cronbach's Alpha values greater than 0.6. Conclusion: The validity test results of KUKUH Questionnaire are considered quite good, with a total score of 0.361 for the correlation coefficient for each question in KUKUH. The reliability test results were deemed satisfactory, with Cronbach's alpha > 0.6. The KUKUH questionnaire can be used to evaluate the quality of life of leprosy patients in Indonesia.

Rail head surface defect magnetic flux leakage signal filtering based on the relativity among the adjacent sensors

Rail is the infrastructure of railway traffic and magnetic flux leakage (MFL) is commonly used to detect the surface defects of ferromagnetic materials such as rail. A correlation-based filtering method is proposed to inhibit the lift-off jamming in MFL detection for the defects in the rail head surface. The detection data is segmented and the two sensors with the minimum correlation coefficient of their outputs in the × direction are found. The possible defect width and depth according to the maximum of each output is estimated and the leakage magnetic field (LMF) of it is calculated. The output of the sensor with smaller correlation coefficient between the calculation LMF and the sensor output is chosen as the reference signal to filter. An experimental system was constructed to detect the artificial defects in the rail head surface, and the experimental results shown that the method reduces the lift-off jamming.

Study of microstructural, mechanical, thermal and tribological properties of graphene oxide reinforced Al–10Ni metal matrix composites prepared by mechanical alloying method

This study focused on the characterization of a new graphene oxide (GO) reinforced Al–10Ni/GO metal matrix composite fabricated by mechanical alloying technique. The effect of ball milling time and sintering temperature on the microstructural evolutions, wear behaviour, mechanical and thermal properties of the fabricated composites were investigated. X-ray diffractometer and scanning electron microscope analysis showed that as the ball milling time increased, the particle size decreased, the homogeneity increased, and the Al3Ni2 intermetallic phase occurred after 40 h of ball milling. The thermal properties of the prepared powder composites were investigated with a differential thermal analyzer (DTA). DTA results showed a series of reaction peaks, which were attributed to the melting of the eutectic Al phase and the crystallization of the Al3Ni2 phase, in the temperature range of 560–655 °C. Also, as the ball milling time and sintering temperature increased, it was observed that the microhardness of the pressed powder alloys increased as a result of cold-welding of the reinforcement with the matrix material, and the occurred intermetallic phases. The maximum microhardness value of Al–10Ni/1 wt%GO composite, which was ball milled for 50 h and heat-treated at 600 °C, was found to be 315 ± 10 HV1. Furthermore, the wear behaviours were investigated under loads of 5–15 N. It was observed that as the load increased, the mass loss increased, and the mass loss decreased as the sintering temperature and milling time increased. In addition, the maximum and minimum coefficients of friction were found to be 0.50 and 0.27, respectively. As a result, it is observed that increasing the amount of GO reinforcement in the matrix from 1 wt% to 2 wt% adversely affects the properties of the composite.

Phase Change and Heat Transfer Analysis of Different Refrigerants During Condensation in Minichannel Using a Novel Numerical Approach

Abstract This paper analyses the condensation heat transfer phenomena in minichannel using acetone, ammonia, propylene, and R134a as the working fluids used in new-age space applications. A novel numerical model is developed considering the changes in local vapor pressure in the channel established due to shrinking in the flow passage by the gradual formation of the liquid layer. The present developed numerical model is compared with the available numerical and experimental results. The impacts of different inlet mass fluxes (250, 500, and 750 kg/m2 s), channel heights (1, 4, 6, and 8 mm), applied heat loads (10, 100, 250, and 500 W), and channel orientations (0 deg, 30 deg, 45 deg, 60 deg, and 90 deg) on the performance of the condensation heat transfer process are investigated. The formation of the thin liquid film layers and evaluation of the liquid–vapor interface profiles are examined. The study reveals that the channel orientation has a marginal influence on the flow pattern for the considered channel length of 20 mm. The maximum change in pressure loss is found at the channel orientation of 45 deg, and the average heat transfer coefficient is almost the same for all the considered orientations. The flow pattern is affected by the increase in mass flux resulting in the delay of heat transfer coefficient fluctuations. The average heat transfer coefficient decreases with increasing heat load, and the minimum average heat transfer coefficient is obtained for heat load, Q = 500 W.

Broadband optical limiting in nanohybrids of graphene grafted peripheral (non-peripheral) pyrene substituted phthalocyanines with a low linear absorption

In nonlinear optics, nanohybrids from the functionalization of graphene and organic molecules can be an interesting area of research. In this work, nanohybrid materials consisting of pyrene conjugated peripheral phthalocyanines and non-peripheral phthalocyanines, which are non-covalently attached to the graphene exhibit broadband optical characteristics and broadband limiting optical behavior through a two-photon absorption process with a high degree of transparency. For confirming non-covalent functionalization, optical as well as spectroscopic studies like UV–vis absorption, fluorescence studies, transient absorption, FTIR, XPS, Raman, AFM techniques, etc., were employed. Distinct morphologies are observed for these nanohybrids, such as -nanohybrids with a cylindrical shape in the non-peripheral case whereas a conical shaped nanohybrids in the peripheral case. Furthermore, Raman studies reveal a shift of 8 cm−1 for the 2D peak of both nanohybrids in comparison with that of graphene confirms the strong π-π interaction, which is the maximum shift in a non-covalent interaction between pyrene attached graphene. In a major finding, a donor-acceptor combination is established in these nanohybrids, which makes them important nonlinear optical materials. The nonlinear absorption coefficients of 112 ± 7 cm/GW and 228 ± 12 cm/GW were obtained for these nanohybrids. Compared to the existing reported values, these nanohybrids with the minimum linear absorption coefficient (1.15 cm−1 and 1.25 cm−1), display broadband nonlinear optical characteristics with low optical limiting thresholds (0.9 and 0.83 Jcm−2), which is achieved through the transfer of electrons from Pc core to pyrene anchored graphene, enable them standout candidates for photonic applications.

Room temperature tunability of ferroelectricity and dielectricity in La and Mn codoped BiFeO3 nanoflakes: Implications for electronic devices applications

This study sheds a light on the in-situ growth of nanoflakes structure in Bi0.9La0.1Fe0.5Mn0.5O3 (BLFMO) thin film. The BLFMO thin films of various thicknesses were grown on LaNiO3 (LNO) coated Si (100) substrates using pulsed laser deposition technique. A long-range crystal structure of the as prepared BLFMO thin films was studied by X-ray diffraction measurements, which shows that the LNO buffer layer allows growth for a specific orientation. The compact and densely packed nanoflake structures in BLFMO thin film samples were confirmed by surface morphological investigations. To measure the polarization versus electric field (p-E) loop of BLFMO chip samples, a standard bipolar sinusoidal waveform with its magnitude of 250 kV/cm was applied at the frequency of 1 kHz. The maximum saturation and remnant polarizations of 104.50 μC/cm2 and 86.24 μC/cm2 respectively were probed for a critical thickness (420 nm) of the BLFMO layer. The voltage polarity-dependent leakage current behavior of Ag/BLFMO/LNO thin-film capacitor is thoroughly explored in detail. The value of leakage current density was observed from 1.16 × 10−4 to 2.24 × 10−5 J/cm2 for BLFMO thin films at an external applied electric field of 300 kV/cm. The highest tunability ∼60.20% and minimum temperature capacitance coefficient ∼1.23 × 10−3 were also observed for the same critical thickness of proposed chip element. The present study may open up a new opportunity to fabricate thin film based ferroelectric memory devices.

Correlating between the height of three-dimensional core-shell electrodes and ion transport for their electrochemical performance

The height of electrodes for in-situ grown 3D core-shell electrodes on a collector, which can directly affect the transport of electrolyte ions, is an important issue that needs to be concerned. Herein, nanocone Co2(OH)2CO3 (CCH) with different heights were synthesized as representative demos to explore the possible factors, including the height h, ion diffusion coefficient D, and Warburg coefficient σ for addressing the ion transport issue. A compromise balance between the height and ion diffusion coefficient was obtained after a series of dynamic analyses. The results showed that the optimal height of CCH can improve ion transport and shorten the charge transfer distance while avoiding stacking and curling. The best electrochemical performance renders the minimum Warburg and maximum ion diffusion coefficients. Furthermore, in-situ EIS and Raman showed that the active sites of CCH were the exposed Co in octahedral units, which can form linkage of octahedrally-electrolyte upon suitable cycling height can reveal more cations, thereby producing more extraordinary electrochemical performance. This work emphasizes the importance of ion diffusion behavior for electrochemical performance within electrodes. It gives a guide for constructing core-shell electrodes with a high electrochemical performance by engineering the microscopic height of materials.

Perfusion and diffusion-weighted imaging parameters: Comparison between pre- and postbiopsy MRI for high-grade glioma.

We aimed to evaluate the differences in dynamic susceptibility contrast (DSC)- magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) parameters between the pre- and postbiopsy MRI obtained before treatment in patients with diffuse midline glioma, H3K27-altered. The data of 25 patients with pathologically proven diffuse midline glioma, H3K27-altered, were extracted from our hospital’s database between January 2017 and August 2021. Twenty (median age, 13 years; range, 3–52 years; 12 women) and 8 (13.5 years; 5–68 years; 1 woman) patients underwent preoperative DSC-MRI and DWI before and after biopsy, respectively. The normalized corrected relative cerebral blood volume (ncrCBV), normalized relative cerebral blood flow (nrCBF), and normalized maximum, mean, and minimum apparent diffusion coefficient (ADC) were calculated using the volumes-of-interest of the tumor and normal-appearing reference region. The macroscopic postbiopsy changes (i.e., biopsy tract, tissue defect, and hemorrhage) were meticulously excluded from the postbiopsy measurements. The DSC-MRI and DWI parameters of the pre- and postbiopsy groups were compared using the Mann–Whitney U test. The ncrCBV was significantly lower in the postbiopsy group than in the prebiopsy group [prebiopsy group: median 1.293 (range, 0.513 to 2.547) versus postbiopsy group: 0.877 (0.748 to 1.205), P = .016]. No significant difference was observed in the nrCBF and normalized ADC values, although the median nrCBF was lower in the postbiopsy group. The DSC-MRI parameters differed between the pre- and postbiopsy MRI obtained pretreatment, although the macroscopic postbiopsy changes were carefully excluded from the analysis. The results emphasize the potential danger of integrating and analyzing DSC-MRI parameters derived from pre- and postbiopsy MRI.

Uniform near magnetic field generated by metasurface-based resonator for wireless power transfer

The modern platforms capable of generating uniform magnetic fields for wireless charging multiple electronic devices have attracted considerable interest in the wireless power transfer realm. This paper proposes a metasurface-based transmitting resonator consisting of two orthogonally placed parallel copper wires layers separated by a high permittivity dielectric layer. The proposed structure of the transmitting resonator allows for generating a uniform magnetic field above the surface. The theoretically estimated minimum coefficient of magnetic field variation is 8.2 % over the central resonator working area with the size of 30 cm × 30 cm, which is sufficient to charge several devices at once. The calculated maximum achievable power transfer efficiency reaches 93.4 %. The simulated value of the resonator’s peak specific absorption rate is twice decreased compared to other metasurface-based designs. The proposed structure could transfer more power under the same safety limitation.

Role of apparent diffusion coefficient measurement in differentiating histological subtypes of brain metastasis of lung cancer

SUMMARYOBJECTIVE:The aim of this study was to investigate the role of apparent diffusion coefficient of diffusion-weighted imaging in differentiating histological subtypes of brain metastasis of lung cancer.METHODS:Diffusion-weighted imaging of 158 patients (mean age: 61.2±10.68 years) with brain metastasis of lung cancer (36 small cell lung cancer and 122 non-small cell lung cancer) were retrospectively evaluated. The minimum and mean apparent diffusion coefficient values of the metastasis, apparent diffusion coefficient of edema around the metastasis, and apparent diffusion coefficient of contralateral brain parenchyma were measured. Normalized apparent diffusion coefficient was calculated by proportioning the mean apparent diffusion coefficient of the metastasis to the apparent diffusion coefficient of the contralateral brain parenchyma. Minimum and mean apparent diffusion coefficient of the metastasis, apparent diffusion coefficient of edema around metastasis, and normalized apparent diffusion coefficient were compared between small cell lung cancer and non-small cell lung cancer metastases.RESULTS:Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, and normalized apparent diffusion coefficient values of small cell lung cancer metastases (0.43±0.19×10−3mm2/s, 0.63±0.20×10−3mm2/s, and 0.81 [0.55–1.44], respectively) were significantly lower than those of non-small cell lung cancer metastases (0.71±0.26×10−3mm2/s, 0.93±0.29×10−3mm2/s, and 1.30 [0.60–3.20], respectively; p<0.001). Mean apparent diffusion coefficient of edema of small cell lung cancer metastases (1.21±0.28×10−3mm2/s) was significantly lower than that of non-small cell lung cancer metastases (1.39±0.26×10−3mm2/s, p=0.020). The best cutoff values of minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema for the differentiation of small cell lung cancer and non-small cell lung cancer were found to be 0.56×10−3mm2/s, 0.82×10−3mm2/s, 1.085, and 1.21×10−3mm2/s, respectively. The area under the receiver operating characteristic curve, sensitivity, and specificity values were, respectively, 0.812, 80.6, and 73.8% for minimum apparent diffusion coefficient; 0.825, 91.7, and 61.5% for mean apparent diffusion coefficient; 0.845, 80.6, and 73.8% for normalized apparent diffusion coefficient; and 0.698, 75.0, and 67.7% for apparent diffusion coefficient of edema.CONCLUSIONS:Minimum apparent diffusion coefficient, mean apparent diffusion coefficient, normalized apparent diffusion coefficient, and apparent diffusion coefficient of edema around metastasis can differentiate histological subtypes of brain metastasis of lung cancer.

Mass transfer in conical spouted beds equipped with internal devices

The gas–solid contact in spouted beds is characterized by a hydrodynamics leading to high heat and mass transfer rates. Several correlations have been proposed for estimating the minimum spouting velocity, and heat and mass transfer coefficients. However, those available for estimating the mass transfer coefficient are not suitable for conical spouted beds equipped with internal devices. Based on drying runs and a drying model already validated, mass transfer coefficients were estimated under different operating conditions and geometries of the internal devices. The features of the bed materials are those of greatest impact, followed by the air inlet temperature and velocity. Although the influence of the dimensions of the internals is less significant, they are also key parameters for the scaling-up of spouted beds. Therefore, a new correlation has been proposed, which accurately predicts the mass transfer coefficient in both plain spouted beds and those equipped with internal devices. • A validated model was used to estimate the mass transfer coefficient in spouted beds. • The geometry of the internal devices greatly influences the mass transfer coefficient. • A new correlation was proposed considering the geometry of draft tubes and confiner. • The correlation accurately predicts the mass transfer coefficient in spouted beds.

Enhanced electromagnetic microwave absorption of SiC nanowire-reinforced PDC-SiC ceramics catalysed by rare earth

Rare earth elements can modulate the dielectric constant of materials and significantly improve their dielectric properties. Herein, SiCnws/SiC ceramics were prepared through polymer derived ceramics (PDCs) technology with rare earth Sc particles as the catalyst. The Sc particles promote the precipitation of SiC and C from the matrix. Furthermore, the SiCnws, grown via the vapour-liquid-solid (VLS) mechanism, construct the three dimensional (3D) network structure to improve impedance matching and loss characteristics. Remarkably, the SiCnws/SiC ceramics minimum reflection coefficient (RCmin) achieved a value of −33.2 dB at 9.4 GHz with a thickness of 2.75 mm, and the effective absorption bandwidth (EAB) was 4.2 GHz covering the whole X band. When microwaves permeated into the SiCnws/SiC ceramics, those trapped in the 3D network structure underwent a variety of microwave energy dissipation processes, including multiple reflections, scattering, and interface and dipole polarisation. Consequently, SiCnws-reinforced PDC-SiC ceramics catalysed by rare earth emerge as a promising new approach to enhance electromagnetic (EM) wave absorption performance.

Microstrip antenna optimization using evolutionary algorithms

Different structures of microstrip antenna optimization using different algorithms are the important field of wireless communications. Rectangular microstrip antenna, inverted E-shaped antenna, tulip shaped antenna are some examples of microstrip antennas. The antenna dimensions are optimized by different algorithms. The operating frequencies for different antenna structures depend on antenna dimensions. The frequency of operation is 3-lS GHz for rectangular antenna, IMT-2000 for invelted E-shaped antenna, 8 to 12 GHz for tulip shaped antenna, 2.16 GHz for miniaturized antenna structure. The dimensions of microstrip antennas are modified to get minimum reflection coefficient maximum gain and bandwidth. The dimensions are modified using different algorithms such as evolutionary algorithm, particle swarm optimization (PSO), artificial neural network (ANN), and genetic algorithms (GA).

Quantification of fabric morphology and prediction of drag crisis based on the fractal dimension

This paper focused on investigating the relationship between fabric morphology and aerodynamic drag. The fractal theory is used to quantify the fabric surface morphology, and its influence on the minimum drag coefficient and critical Reynolds number is evaluated. In addition, the effectiveness of the fractal dimension in predicting the drag crisis is verified. It is observed that with the increase of the fractal dimension, the minimum drag coefficient increases, and the correlation coefficient can reach 0.9728, while the corresponding critical Reynolds number decreases, and the correlation coefficient can reach 0.9334. In addition, the accuracy of predicting drag crisis by the fractal dimension is verified and the relative error of predicting the drag crisis by the fractal dimension is less than 10%, which is significantly better than that by roughness.

Retrieving instantaneous extinction of aerosol undetected by the CALIPSO layer detection algorithm

Abstract. Aerosols significantly affect the Earth–atmosphere energy balance and climate change by acting as cloud condensation nuclei. Specifically, the susceptibility of cloud and precipitation to aerosols is stronger when aerosols are faint but tends to be saturated in polluted conditions. However, previous methodologies generally miss these faint aerosols based on instantaneous observations because they are too optically thin to be detected and are therefore usually unretrieved. This result in a large underestimation when quantifying aerosol climate impacts. Here, we focus on retrieving and verifying the instantaneous extinction of undetected faint aerosol by the CALIPSO layer detection algorithm on a global scale. Using the observations during the Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) as constraints, the lidar ratios of undetected faint aerosol are estimated with a global median of 42.2 and 24.5 sr at the stratosphere and the troposphere, respectively. The retrieved extinction of undetected aerosol during night-time shows good agreement with the independent 12-month SAGE III/ISS product on a 1∘ average. The corresponding correlation coefficient and averaged normalized root-mean-square error are 0.66 % and 100.6 %, respectively. The minimum retrieved extinction coefficients can be extended to 10−3 and 10−4 km−1 with an uncertainty of 35 % and 125 % during night-time, respectively. The CALIPSO retrieval during daytime has a positive bias and relatively low agreement with SAGE III/ISS due to the low signal-to-noise ratio caused by sunlight. This study has great potential for improving the understanding of aerosol variations and the quantification of aerosol impacts on global climate change.

PERFORMANCE EVALUATION OF BLACK SOAP (TOILET SOAP) BLENDED WITH DE-OILED JATROPHA CAKE ADDITIVE AS SOLID LUBRICANT IN DIRECT COLD EXTRUSION OF ALUMINIUM ALLOYS

The use of petro-lubricants in metal forming leads to lamination of oxide on the extrudates due to temperature increase and reaction of the base metal with some elements in the lubricant, hence resulting poor surface quality of the end product. The non-biodegradability of these lubricants also leads to environmental pollution. Although De-oiled Jatropha Caked has been volarised for so many applications, with some oil left in the cake it can still be employed for use in other applications. In this paper a bio-solid lubricant is formulated from Black soap (Toilet soap-vegetable oil-based) as base and De-oiled Jatropha cake as additive. Jatropha seeds were processed to ≤ 0.5 um particles size powder and de-oiled using Soxhlet apparatus. Black soap and de-oiled Jatropha cake was then mixed in ratios: 90:10, 80:20, 70:30, 60:40 and 50:50. Each of these was further mixed with de-ionized lukewarm water in ratio 50:50 by weight to produce solid lubricant blends B1, B2, B3, B4 and B5, respectively. Each of the Black soap-enriched solid lubricant blends were then used to test for coefficient of friction on mirrored surface prepared aluminum specimens using Ball-on-disc Tribometer. The solid lubricant blends were again used to conduct Extrusion tests on Ø25.4 mm by 25.4mm aluminum alloy billets in direct cold extrusion process on a 2000 KN capacity UT CO821 machine. The results showed blend B3 (70:30) recording the minimum coefficient of friction and extrusion force values μ=0.732 and 170.53KN, respectively. These results reveal that enriched solid lubricant B3 (70:30) is most suitable for aluminum alloys extrusion.

Dry Sliding Tribological Behavior of Cryotreated Cr–V Ledeburitic Tool Steel against CuSn6 Counterpart

The purpose herein is to assess the impact of different combinations of cryogenic treatments and tempering regimes on tribological properties of Cr–V tool steel against a CuSn6 counterpart. Dry sliding wear experiments are performed using a pin‐on‐disk tribometer according to the Taguchi method. Tribological behavior is investigated under four process parameters at mixed levels: cryotemperatures (−75, −140, or −196 °C), tempering temperatures (170 or 530 °C), sliding velocity (0.064, 0.128, 0.1885 m s−1), and load (1, 5, 10 N). According to the analysis, the minimum friction coefficient is obtained by cryotreatment at −140 °C combined with 170 °C tempering, with a sliding velocity of 0.128 m s−1 and load of 10 N. For the minimum counterpart´s material adhesion level, cryogenic treatment at −196 °C followed by tempering at 530 °C, sliding velocity of 0.1885 m s−1, and applied load of 1 N are the optimum settings. The analysis of variance model shows that the load (39.2%) has statistical significance on the friction coefficient, while the load (59.1%) and tempering temperature (18.0%) have statistical significance on adhesion levels. The tribological behavior of the steel is explained by thorough microstructural examinations using scanning electron microscopy coupled with energy‐dispersive spectroscopy.

Controllable synthesis of ScFeO3 ceramics with microstructural evolution for thin and broadband high-performance microwave absorption

Controlled microstructures play a pivotal role in upgrading the microwave absorption properties of materials. Herein, ScFeO3 ceramics with a controllable three-dimensional (3D) network structure were prepared by adjusting the sintering temperature. Specifically, the effect of sintering temperature on microstructure and microwave absorption properties were investigated. The results show that ScFeO3 ceramics with the sintering temperature of 1300 ºC possess the superior dielectric and magnetic loss capabilities for incident microwaves, which attributes to the ideal 3D network microstructure enhancing the impedance matching characteristic. Besides, this unique 3D network microstructure not only provides multiple channels for multiple reflecting and scattering of microwaves, but also offers abundant interfaces to dissipate microwaves. Furthermore, the natural resonance effect efficiently increases the magnetic loss. The optimal ScFeO3 samples possess the minimum reflection coefficient (RCmin) of − 57.4 dB at 17.44 GHz with a thickness of 2.45 mm and an effective absorption bandwidth (EAB) covering the whole Ku band (5.6 GHz) with a thickness range of 1.35–1.55 mm. It is believed that ScFeO3 ceramics can be new promising microwave absorption material with thin, broadband, and strong absorption performance.

Experimental investigation on the wave performance with the interference of floating aquaculture cages in single and tandem arrangements

Floating aquaculture cages deployed in the nearshore affect the wave field and contribute to the coastal defense by damping incoming waves. Most pioneering works concerning aquaculture cages have concentrated on the hydrodynamics of the structures instead of their influence on the wave field. In order to bridge the gap, this paper examines the wave performance with the interference of floating aquaculture cages via physical model tests. The results show that the existence of cages increases wave height on the weather side. The wave-dissipation performance of the net cage is closely related to the ratio of the wavelength to the structural span, and the minimum transmission coefficients appear in the conditions with the maximum wave number. Moreover, the crests of the free surface elevation inside the floating frames are almost flat, which is particularly obvious in the long-period wave conditions. The surface elevations show nonlinearity in small-wavelength conditions, which is dominantly caused by the pitch motion of the cages. Nevertheless, the presence of the cage does not affect the phase differences in the wave elevation at different positions. The nets have an opposite effect on wave response inside the cage under the conditions of long-period and short-period waves.

T1 and ADC histogram parameters may be an in vivo biomarker for predicting the grade, subtype, and proliferative activity of meningioma.

To investigate the value of histogram analysis of T1 mapping and diffusion-weighted imaging (DWI) in predicting the grade, subtype, and proliferative activity of meningioma. This prospective study comprised 69 meningioma patients who underwent preoperative MRI including T1 mapping and DWI. The histogram metrics, including mean, median, maximum, minimum, 10th percentiles (C10), 90th percentiles (C90), kurtosis, skewness, and variance, of T1 and apparent diffusion coefficient (ADC) values were extracted from the whole tumour and peritumoural oedema using FeAture Explorer. The Mann-Whitney U test was used for comparison between low- and high-grade tumours. Receiver operating characteristic (ROC) curve and logistic regression analyses were performed to identify the differential diagnostic performance. The Kruskal-Wallis test was used to further classify meningioma subtypes. Spearman's rank correlation coefficients were calculated to analyse the correlations between histogram parameters and Ki-67 expression. High-grade meningiomas showed significantly higher mean, maximum, C90, and variance of T1 (p = 0.001-0.009), lower minimum, and C10 of ADC (p = 0.013-0.028), compared to low-grade meningiomas. For all histogram parameters, the highest individual distinctive power was T1 C90 with an AUC of 0.805. The best diagnostic accuracy was obtained by combining the T1 C90 and ADC C10 with an AUC of 0.864. The histogram parameters differentiated 4/6 pairs of subtype pairs. Significant correlations were identified between Ki-67 and histogram parameters of T1 (C90, mean) and ADC (C10, kurtosis, variance). T1 and ADC histogram parameters may represent an in vivo biomarker for predicting the grade, subtype, and proliferative activity of meningioma. • The histogram parameter based on T1 mapping and DWI is useful to preoperatively evaluate the grade, subtype, and proliferative activity of meningioma. • The combination of T1 C90 and ADC C10 showed the best performance for differentiating low- and high-grade meningiomas.