Array Of Plates Research Articles

Effects of Overlap Length on Flammability and Fire Hazard of Vertical Polymethyl Methacrylate (PMMA) Plate Array.

Polymethyl methacrylate (PMMA) plates are widely used in buildings or factories for natural lighting. Commonly PMMA plates are installed as a discrete array. However, PMMA plates are very susceptible to fire. Therefore, experimental study on flammability and fire hazard of vertical PMMA plate array with different overlap length (D) was conducted in this work. The average flame height () increases first and then decreases with an increase in the overlap length, and reaches the maximum when D = 40 mm. The discrete flame spread speed () also rises first and then drops with the increase of D, which is mainly due to the heat transfer from the PMMA flame to the next plate. A model for predicting the flame spread rate of discrete PMMA array is established. The predicted results are consistent with experimental ones, with a predicted error smaller than 15%. The average temperature of flame zone rises first and then drops as D increases, reaching the maximum when D = 40 mm. This leads to the same changing trend of radiative heat flux. Results obtained in this work provide a reference for fire hazard evaluation and fire safety design of PMMA plates employed in buildings or industrial sites.

Study on optical hierarchical sorting of particles based on the Fraunhofer diffraction field of spiral phase plate array

Optical hierarchical sorting has attracted significant attention in recent years. The existing approaches use either complex numerical calculation or computer-aided experimental tools for optical hierarchical sorting. We proposed a method to perform hierarchical sorting, which is computationally simple and does not need computer aid. In particular, we employed a focused optical vortices array (FOVA), which is generated and focused by a spiral phase plate array (SPPA) and a microlens array, respectively. We designed different heights for the spiral phase plate in different columns of the SPPA. This enabled different columns of the FOVA to carry different topological charges and consequently possess different capture capabilities. To realize hierarchical sorting, we exploited the properties of FOVA by deploying it in a microfluidic chamber containing particles of various sizes. The four columns of the FOVA formed four corresponding capture regions in the flow area of the particles. From our theoretical analysis and numerical results, we observed that particle sizes in the range of 1 to 582 nm could be sorted. Our approach provides a theoretical framework that can be readily employed in experiments for optical hierarchical sorting.

Multi-beam X-ray ptychography for high-throughput coherent diffraction imaging

X-ray ptychography is a rapidly developing coherent diffraction imaging technique that provides nanoscale resolution on extended field-of-view. However, the requirement of coherence and the scanning mechanism limit the throughput of ptychographic imaging. In this paper, we propose X-ray ptychography using multiple illuminations instead of single illumination in conventional ptychography. Multiple locations of the sample are simultaneously imaged by spatially separated X-ray beams, therefore, the obtained field-of-view in one scan can be enlarged by a factor equal to the number of illuminations. We have demonstrated this technique experimentally using two X-ray beams focused by a house-made Fresnel zone plate array. Two areas of the object and corresponding double illuminations were successfully reconstructed from diffraction patterns acquired in one scan, with image quality similar with those obtained by conventional single-beam ptychography in sequence. Multi-beam ptychography approach increases the imaging speed, providing an efficient way for high-resolution imaging of large extended specimens.

Plate arrays as a perfectly-transmitting negative-refraction metamaterial

A closely-spaced periodic array of identical thin rigid plates illuminated by incident waves is shown to exhibit properties of a negative refraction metamaterial under certain conditions. The close-spacing assumption is used as a basis for an approximation in which the region occupied by the plate array acts as an effective medium. Effective matching conditions on the plate array boundary are also derived. The approximation allows explicit expressions to be derived to wave scattering problems involving tilted plate arrays. This approximation is tested for its accuracy against an exact treatment of the problem based on Bloch–Floquet theory.Both the exact and effective medium theory predict perfect wave transmission at all wave frequencies through the array when the tilt angle of plates in the array is the reverse of the incident wave direction: the array acts as an all-frequency perfectly-transmitting negative-refraction medium. For certain frequencies the array is also shown to act as an all-angle perfectly-transmitting negative-refraction material.

GENECHOC study: genetic markers of arrhythmic risk in heart failure

Abstract Background Ventricular arrhythmic events are responsible for 50% of death in heart failure but no reliable predictive marker is known to discriminate patients at risk of fatal arrhythmia. Interestingly, familial predisposition has been reported suggesting a role of genetic factors. Purpose Identify genetic markers increasing the arrhythmic risk in heart failure population. Method We prospectively included heart failure patients with left ventricular ejection fraction (LVEF) under 35% and a cardioverter defibrillator in primary prevention in 22 French centres between 2009 and 2017. Patients were followed for 72 months and divided into two groups: cases with an arrhythmic event during follow-up and controls. A Genome Wide Association Study (GWAS) was done. Single Nucleotide Polymorphisms (SNPs) genotyping was performed on Affymetrix Axiom Precision Medicine Research Array plates. To complement the directly genotyped SNPs we performed large-scale imputation based on the Haplotype Reference Consortium European ancestry panel leading to a dataset of 7,5 million of SNPs. Results 332 cases and 567 controls were included (86% men, mean age at implantation 52±11 years). 78% of patients had ischaemic cardiopathy, 20% had dilated cardiomyopathy. Mean LVEF was 27±5%. No statistical difference was found between cases and controls on clinical parameters, biological results, electrocardiographic measures. No locus shows genome-wide significant association (p<5.10–8) on the GWAS analysis. However, 16 signals with a p-value between 5.10–8 and 5.10–5 were investigated. eQTL and chromatin conformation point to 35 genes with cardiac expression previously associated with heart failure, cardiomyopathies, cardiogenesis, arrhythmias and inflammation. Variants identified point to regulatory regions of the genome and may then propose a molecular mechanism predisposing patients to arrhythmias. Conclusion No locus raises genome-wide significance, but several signals with a nominal p-value point to relevant genes and pathways. Replication of the GWAS is ongoing on a cohort of 156 new patients with a less severe cardiopathy implanted with a cardioverter defibrillator in secondary prevention. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Nantes University Hospital

Novel R-test measurement system to detect thermally induced volumetric accuracy in horizontal machine tools

Because of uneven temperature distributions, machine tools can generate thermal errors, which significantly contribute to machining errors. Previous research has shown that thermal volumetric errors can be directly measured using optical methods or indirectly calculated using error mapping methods. However, these methods are limited to or restricted by specific working conditions. Therefore, our study focused on developing a novel R-test measurement system for realising accurate thermal volumetric error measurements. The R-test measurement system consists of a three-dimensional (3D) ball array plate, R-test detecting head, temperature monitoring module, and data processing module. This system allows the measurement of deviation in the X, Y, and Z directions simultaneously at different fixed points in a 3D cube. Furthermore, considering the temperature and thermally induced volumetric accuracy, it was possible to derive the deformation tendency of the machine tool. An uncertainty analysis and systematic error corrections were conducted. The measurement uncertainty of this system is approximately 4 μm. The thermal volumetric errors were examined using the developed R-test measurement system and an interferometer under the same thermal conditions. The experimental results indicated that the R-test measurement system was able to accurately and rapidly detect thermal volumetric errors. This system provides a measurement technique with a low level of uncertainty, high accuracy, and low cost, which can be used to measure, compensate, and control the thermally induced volumetric accuracy of horizontal machine tools.

Wave scattering by an array of metamaterial cylinders

Abstract

Genechoc Study Genetic markers of arrhythmic risk in heart failure

Ventricular arrhythmic events are responsible for 50% of death in heart failure but no reliable predictive marker is known to discriminate patients at risk of fatal arrhythmia. Interestingly, familial predisposition has been reported suggesting a role of genetic factors. Identify genetic markers increasing the arrhythmic risk in heart failure population. We prospectively included heart failure patients with left ventricular ejection fraction (LVEF) under 35% and a cardioverter defibrillator in primary prevention in 22 French centres between 2009 and 2017. Patients were followed for 72 months and divided into two groups: cases with an arrhythmic event during follow-up and controls. A Genome Wide Association Study (GWAS) was done. Single Nucleotide Polymorphisms (SNPs) genotyping was performed on Affymetrix Axiom Precision Medicine Research Array plates. 332 cases and 567 controls were included (86% men, mean age at implantation 52 ± 11 years). 78% of patients had ischaemic cardiopathy, 20% had dilated cardiomyopathy. Mean LVEF was 27 ± 5%. No statistical difference was found between cases and controls on clinical parameters or electrocardiographic measures. No locus shows genome-wide significant association ( P < 5.10 − 8) on the GWAS analysis. However, 16 signals with a p-value between 5.10 − 8 and 5.10 − 5 were investigated. eQTL and chromatin conformation point to 35 genes with cardiac expression previously associated with heart failure, cardiomyopathies, arrhythmias and inflammation. Variants identified point to regulatory regions of the genome and may then propose a molecular mechanism predisposing patients to arrhythmias ( Fig. 1 ). No locus raises genome-wide significance, but several signals with a nominal p-value point to relevant genes and pathways. Replication of the GWAS is ongoing on a cohort of 156 new patients with a less severe cardiopathy implanted with a cardioverter defibrillator in secondary prevention.

Development and experimental verification of an adaptive structure for phased antenna array using SMA bunch

An adaptive structure for a phased antenna array is proposed using shape memory alloy (SMA) as an actuation component for the plate flatness control. Fiber Bragg Grating (FBG) sensors are designed for plate strain measurement, and a strain displacement transformation method is introduced to obtain the deformation field from the strain measurement data. The deformation field is then used to determine the correction loads of actuation points using integer nonlinear programming analysis. An adaptive prototype for the phased antenna array plate is developed with the distribution of monitored, actuation, and load points. Numerical simulations are performed to demonstrate the detailed process of the strain displacement transformation method. Moreover, the method is further discussed after testing the adaptive plate structure with the digital image correlation (DIC) technology. Finally, the reliability and efficiency of the proposed active control scheme are validated with an experimental setup. The study promotes the engineering application of the active control concept in large scale phased antenna arrays.

Bragg scattering of long waves by an array of floating flexible plates in the presence of multiple submerged trenches

Bragg scattering of long gravity waves by an array of floating elastic plates in the presence of a series of rectangular trenches is studied under the assumption of linearized water wave theory and small amplitude structural response. Bragg reflection occurs in the case of an array of multiple floating flexible plates and trenches in isolation or combination, and the number of sub-harmonic peaks between two consecutive peaks is two less than the number of plates/trenches. In the case of long-wave scattering by an array of trenches in the absence of floating plates, wave reflection becomes zero minimum for a certain fixed wavenumber at the end of the first cycle (as referred to 0 &amp;lt; k1h1 &amp;lt; 0.32), irrespective of the even/odd number of trenches. Furthermore, the Bragg resonant reflection pattern of the second cycle is a mirror image of the reflection occurring in the first cycle. Conversely, the symmetric pattern of Bragg reflection exhibited in the case of an array of trenches does not occur for an array of plates in isolation or for plates and trenches in combination. Between consecutive harmonic peaks, the minima/maxima in the wave reflection occur in the case of the even/odd number of trenches/plates in isolation. In contrast, it occurs within the first cycle in the case of trenches and plates in combination. Between consecutive harmonic peaks, maxima/minima of wave reflection coincide for a certain wavenumber, irrespective of the even/odd number of trenches/plates in isolation. In addition, these maxima attained for a certain wavenumber for the even number of trenches/plates are 180° out of phase to that of minima for an odd number of trenches/plates. However, similar phenomena occur within the first cycle of Bragg resonance in the case of trenches and plates in combination. Moreover, the amplitude of oscillation in the wave reflection increases with an increase in plate rigidity. Time-dependent motion due to Bragg scattering by trenches and plates is demonstrated in different cases.

Dual-Polarized Wideband Plate Array Antenna With High Polarization Isolation and Low Cross Polarization for D-Band High-Capacity Wireless Application

This letter presents a dual-polarized wideband plate array antenna in D-band for future fixed high-capacity wireless communication. To achieve the high polarization isolation and wideband operation at the same time, a two-stage multimode cavity is introduced, consisting of a polarization isolation cavity and a cascaded dividing cavity. They are combined to optimize and improve the bandwidth of the dual-polarized antenna array. The TE210 and TE120 degenerate modes are selected to resonate in the cavity. They can be used to generate two orthogonal linear polarization modes with the extremely low cross polarization after cascading four integrated horns with a proper placement. To validate the design, an 8 × 8 element array is fabricated by the diffusion bonding of laminated thin copper plates technology. The gain is more than 24.5 dBi from 130 to 149 GHz. The isolation between two channels is higher than 50 dB and the cross polarization level is below −45 dB over the whole band.

Hydroelastic interaction between water waves and an array of circular floating porous elastic plates

Abstract

Circulating and Adipose Tissue miRNAs in Women With Polycystic Ovary Syndrome and Responses to High-Intensity Interval Training.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally. In women with polycystic ovary syndrome (PCOS), several miRNAs are differentially expressed compared to women without PCOS, suggesting a role for miRNAs in PCOS pathophysiology. Exercise training modulates miRNA abundance and is primary lifestyle intervention for women with PCOS. Accordingly, we measured the expression of eight circulating miRNAs selected a priori along with miRNA expression from gluteal and abdominal adipose tissue (AT) in 12 women with PCOS and 12 women matched for age and body mass index without PCOS. We also determined the miRNA expression “signatures” before and after high-intensity interval training (HIT) in 42 women with PCOS randomized to either: (1) low-volume HIT (LV-HIT, 10 × 1 min work bouts at maximal, sustainable intensity, n = 13); (2) high-volume HIT (HV-HIT, 4 × 4 min work bouts reaching 90–95% of maximal heart rate, n = 14); or (3) non-exercise control (Non-Ex, n = 15). Both HIT groups trained three times/week for 16 weeks. miRNAs were extracted from plasma, gluteal and abdominal AT, and quantified via a customized plate array containing eight miRNAs associated with PCOS and/or exercise training responses. Basal expression of circulating miRNA-27b (c-miR-27b), implicated in fatty acid metabolism, adipocyte differentiation and inflammation, was 1.8-fold higher in women with compared to without PCOS (P = 0.006) despite no difference in gluteal or abdominal AT miR-27b expression. Only the HV-HIT protocol increased peak oxygen uptake (VO2peak L/min; 9%, P = 0.008). There were no changes in body composition. In LV-HIT, but not HV-HIT, the expression of c-miR-27b decreased (0.5-fold, P = 0.007). None of the remaining seven circulating miRNAs changed in LV-HIT, nor was the expression of gluteal or abdominal AT miRNAs altered. Despite increased cardiorespiratory fitness, HV-HIT did not alter the expression of any circulating, gluteal or abdominal AT miRNAs. We conclude that women with PCOS have a higher basal expression of c-miR-27b compared to women without PCOS and that 16 weeks of LV-HIT reduces the expression of this miRNA in women with PCOS. Intense exercise training had little effect on the abundance of the selected miRNAs within subcutaneous AT depots in women with PCOS.

Fast and spectrally accurate numerical methods for perforated screens (with applications to Robin boundary conditions)

AbstractThis paper considers the use of compliant boundary conditions to provide a homogenized model of a finite array of collinear plates, modelling a perforated screen or grating. While the perforated screen formally has a mix of Dirichlet and Neumann boundary conditions, the homogenized model has Robin boundary conditions. Perforated screens form a canonical model in scattering theory, with applications ranging from electromagnetism to aeroacoustics. Interest in perforated media incorporated within larger structures motivates interrogating the appropriateness of homogenized boundary conditions in this case, especially as the homogenized model changes the junction behaviour considered at the extreme edges of the screen. To facilitate effective investigation we consider three numerical methods solving the Helmholtz equation: the unified transform and an iterative Wiener–Hopf approach for the exact problem of a set of collinear rigid plates (the difficult geometry of the problem means that such methods, which converge exponentially, are crucial) and a novel Mathieu function collocation approach to consider a variable compliance applied along the length of a single plate. We detail the relative performance and practical considerations for each method. By comparing solutions obtained using homogenized boundary conditions to the problem of collinear plates, we verify that the constant compliance given in previous theoretical research is appropriate to gain a good estimate of the solution even for a modest number of plates, provided we are sufficiently far into the asymptotic regime. We further investigate tapering the compliance near the extreme endpoints of the screen and find that tapering with $\tanh $ functions reduces the error in the approximation of the far field (if we are sufficiently far into the asymptotic regime). We also find that the number of plates and wavenumber has significant effects, even far into the asymptotic regime. These last two points indicate the importance of modelling end effects to achieve highly accurate results.

Development of a morphological color image processing algorithm for paper-based analytical devices

Although fabrication of colorimetric paper-based analytical devices (PADs) has drawn increasing attention recently, the signal readout method is still a crucial challenge on the way to practical exploitations. We herein introduce an integration of digital image processing with a model PAD for easing and improving the signal readout procedure. The colorimetric detection mechanism of PAD relies on in-situ induced yellowish silver nanoparticles via the interaction of silver ions, poly(vinyl alcohol), and ammonia with isoniazid. The observed color value is related with the concentration of isoniazid. The proposed algorithm is based on mathematical morphology recognition, and minimizes the errors arising from manual area selection. Besides, it allows the recognition of both circle and square shapes in 96-well plate and A4 size array designs. Since this algorithm automatically provides the blank-corrected numerical matrixes and image profiles of red, green and blue channels, further investigations such as outlier classification, construction of regression/prediction models and calculation of detection limit can be easily performed. Comparison of signal readout results of the developed algorithm with ImageJ software demonstrates significant improvements in analysis speed, reproducibility, accuracy and color values. Therefore, application of the proposed algorithm is promising as a robust technique for practical applications.

Analysis and observation of the breakdown of Babinet\u2019s principle in complementary spoof surface plasmon polariton structures

A metal plate array (MPA) which is a structure complimentary to a metal hole array (MHA), supports spoof surface plasmon polaritons (SSPP) as well as an MHA does. Babinet’s principle attributes the phenomenon of duality to transmission characteristics of the complimentary impedance surfaces because of the symmetry of the behaviors of electric and magnetic fields. However, it is also a fact that the complimentary structures do not follow this principle if they have wavelength-size thickness, because electromagnetic waves do not treat such thick structures as a boundary surface but as propagation spaces with the specific boundaries such as a waveguide which shows SSPP modes. If the thickness is so small that it is negligible, Babinet’s principle is still valid, while it has been uncertain how the layer thickness works to break the principle as it is increased. The unconfirmed transformation is revealed analytically and experimentally with the use of MPAs and MHAs of varying thicknesses.

Effects Of High-intensity Interval Training On The Expression Of Circulating Micro-RNAs In Women With Polycystic Ovary Syndrome

PURPOSE: 1) To compare the expression of circulating miRNAs (c-miRNAs) in women with and without Polycystic Ovary Syndrome (PCOS), and 2) to determine the effects of two different high intensity training (HIT) protocols in women with PCOS on c-miRNA expression. METHODS: Women with PCOS were randomised to one of three conditions: 1) 10 × 1 min “all-out” work bouts (HIT1, n=13); 2) 4 × 4 min work bouts at 90-95% of HRmax (HIT4, n=14); 3) Control (Non-Ex, n=15). Both HIT groups exercise trained 3 x per week for 16 weeks. c-miRNAs were quantified before and after 16 weeks. c-miRNAs were extracted from plasma and quantified via a customised plate array with real-time PCR in women with (n=42; 29 ± 5 years; BMI, 31.2 ± 7.0 kg/m2; VO2peak, 32.7 ± 7.3 mL/kg/min) and without PCOS (Non-PCOS, n=12; 30 ± 6 years; BMI, 29.3 ± 5.5 kg/m2; VO2peak, 34.9 ± 6.7 mL/kg/min). Women without PCOS were age- and BMI-matched to 12 women with PCOS. The array contained 8 c-miRNAs previously reported to associate with PCOS and/or training response. RESULTS: Women with PCOS had a higher basal expression of c-miRNA-27b compared to Non-PCOS (P=0.006, 269 ± 184% difference). Non-Ex had a higher basal expression of c-miRNA-27b compared to both HIT1 (P=0.003, 30 ± 52%) and HIT4 (P=0.003, 45 ± 52%). miRNA-27b is associated with hormone metabolism, inflammation, adipogenesis and is positively correlated with testosterone. No observed basal differences in c-miRNA-146a and c-miRNA-223. Following the training intervention, HIT4 increased VO2peak with 2.0 ± 3.4 mL/kg/min (P=0.020). Non-Ex had a higher expression of c-miRNA-27b compared to HIT1 (P<0.001, 96 ± 126%) and HIT4 (P=0.005, 95 ± 126%). No changes in the expression of c-miRNA-27b occurred within groups after training. The expression of c-miRNA-146a and -223 were lower in HIT4 compared to Non-Ex after the training (P=0.043, 156 ± 105% and P=0.040, 184 ± 106%, respectively). miRNA-223 is linked to hypertension, apoptosis of endothelial cells and type 2 diabetes, whereas miRNA-146a is linked to reducing progesterone, estradiol and testosterone release. CONCLUSION: c-miRNA-27b might have a role as biomarker for women with PCOS and high intensity interval training has the potential to decrease the expression of c-miRNA-146a and -223 in women with PCOS compared to non-exercising women with PCOS.

Effective model for elastic waves propagating in a substrate supporting a dense array of plates/beams with flexural resonances

We consider the effect of an array of plates or beams over a semi-infinite elastic ground on the propagation of elastic waves hitting the interface. The plates/beams are slender bodies with flexural resonances at low frequencies able to perturb significantly the propagation of waves in the ground. An effective model is obtained using asymptotic analysis and homogenization techniques, which can be expressed in terms of the ground alone with effective dynamic (frequency-dependent) boundary conditions of the Robin’s type. For an incident plane wave at oblique incidence, the displacement fields and the reflection coefficients are obtained in closed forms and their validity is inspected by comparison with direct numerics in a two-dimensional setting.

D-Band Wideband Air-Filled Plate Array Antenna With Multistage Impedance Matching Based on MEMS Micromachining Technology

A wideband air-filled plate array antenna with multistage impedance matching operated in D-band is proposed in this article. To achieve the wide bandwidth, three stages of impedance matching are introduced in the 2 × 2 subarray, including the step-profiled horn element, the step-profiled power divider cavity with two resonant points, and a modified E-plane bend transition. The integrated step-profiled horn with simple configuration can realize broadband matching. Wideband T-junctions are combined together to form a corporate feeding network. Essential matching pins are introduced to break through the upper bandwidth restriction of the feeding network. In addition, the square aperture shape of the horn element and the air-filled feeding structure contribute to the high radiation efficiency of the proposed array. To satisfy the fabrication tolerance, the MEMS micromachining technology with a high etching precision is utilized. The experimental results show a wide 1 dB down gain bandwidth of 23.54%. The maximum gain is 33.24 dBi and the peak efficiency is 70.91%.

A Multiplexed Microarray Platform for Targeted Proteomics

A Multiplexed Microarray Platform for Targeted Proteomics