Array Length Research Articles

Integration of size separation and transport of granular particles by a posts array on a conveyor belt

We experimentally design an integrated system composed of a conveyor belt and a posts array, which can simultaneously implement the function of size separation and transportation of disk particles. Differently sized particles through the post array exhibit two types of distinct migration modes that are responsible for the size separation. Furthermore, the dividing line between the two migration modes depends on the critical radius found in experiment. The relationship between the separation efficiency and the length of the post array and the packing fraction of particles is investigated quantitatively. Finally, a simplified model is proposed to predict a critical particle radius which is verified to be in accordance with experimental measurements. This research has a potential application prospect in some fields of industry.

In-plane compression behaviors of the auxetic star honeycomb: Experimental and numerical simulation

In this study, two types of star honeycombs with different cell-wall angles were fabricated by additive manufacturing technology for in-plane compression tests. Experiment results show that the cell-wall angle has no evident effect on the deformation modes, but the small cell-wall angle can improve the energy absorption capacity of star honeycombs. In addition, the unilateral horizontal maximum strain (UHMS) is proposed to evaluate the deformation stability of the honeycomb. Subsequently, numerical simulations are conducted to further investigate the influences of macro and micro geometric parameters on the in-plane compression behavior of star honeycombs. The results show that reducing the orthogonal array ratio and length of the ligament can significantly enhance the deformation stability and energy absorption capacity. Moreover, in accordance with the deformation mechanisms of a typical cell, a theoretical model is established to predict the plateau stress of star honeycomb under quasi-static loading. The theoretical results are in good agreement with the simulation results. Finally, three types of improved star honeycombs (ISH) are constructed by adjusting the ligament length, which improved the specific energy absorption by 30% compared with the classic star honeycomb. Besides, the ISH-II exhibits a stable deformation mode with a significant NPR effect. The results are expected to provide references for designing and optimizing the star honeycomb structure.

Multichannel analysis of surface waves based on short array stacked Correlation gather

Multichannel analysis of surface waves (MASW) has played an important role in shear wave velocity survey of subsurface. Modern urban engineering construction needs more and more high-resolution detection of shallow underground objects. However, the traditional MASW method will reduce the detection depth when the receiving array length is reduced to improve lateral resolution. We propose a modified multichannel analysis method of surface waves based on short array stacked correlation gather (SCG-MASW) to solve this problem. The geometry of SCG-MASW is same as MASW, but surface wave dispersion is derived from short array stacked correlation gather instead of shot gather. Both theoretical and experimental data show that the SCG-MASW can improve the lateral resolution by using short receiving array, while not reducing the detection depth.

Quantitative analysis and optimization design of the segmented planar integrated optical imaging system based on an inhomogeneous multistage sampling lens array.

The non-uniformity of the lens array in the segmented planar integrated optical imaging system has not been studied. We design an inhomogeneous multistage sampling lens array based on a hierarchical multistage sampling lens array of the segmented planar integrated optical imaging system by changing the radius of the lenslet for frequency-selective sampling to optimize the design of the UV spatial frequency distribution. The signal transfer model of the proposed imaging system was established considering the radius of the lenslet and key waveguide parameters. Simulation results show that the proposed system produces better imaging quality owing to the selective sampling of frequency. Compared with the homogeneous multistage sampling lens array (radius of 1.8 mm), the optimal radius parameters of the inhomogeneous multistage sampling lens array are given for the same longest lens array length. Detailed calculations of the parameters of the waveguide connected to the lens array were performed. Our results provide a theoretical basis for the optimal design and process of a new segmented planar integrated optical imaging system.

Correlation of Electrically Evoked Compound Action Potential Amplitude Growth Function Slope and Anamnestic Parameters in Cochlear Implant Patients-Identification of Predictors for the Neuronal Health Status.

Cochlear implants (CI) are the treatment of choice in profoundly deaf patients. Measuring the electrically evoked compound action potential (ECAP) has become an important tool for verifying the function of the spiral ganglion neurons (SGN), which are the target cells of the CI stimulation. ECAP measurement is only possible after electrode insertion. No information about the neuronal health status is available before cochlear implantation. We investigated possible correlations between the ECAP amplitude growth function (AGF) slope and anamnestic parameters to identify possible predictors for SGN health status and therefore for CI outcome. The study included patients being implanted with various electrode array lengths. Correlation analysis was performed for the mean AGF slope of the whole array, for separate electrodes as well as for grouped electrodes of the apical, medial, and basal region, with duration of deafness, age at implantation, residual hearing (grouped for electrode length), and etiology. The mean ECAP AGF slopes decreased from apical to basal. They were not correlated to the length of the electrode array or any etiology. For the mean of the full array or when grouped for the apical, middle, and basal part, the ECAP AGF slope was negatively correlated to the duration of hearing loss and the age at implantation. Since a significant negative correlation of the ECAP AGF slope and age at cochlear implantation and duration of deafness was observed, this study supports the statement that early implantation of a CI is recommended for sensorineural hearing loss. Additional factors such as the cochlear coverage and insertion angle influence the ECAP AGF slope and performance of the patient and should be included in future multifactorial analysis to study predictive parameters for the CI outcome.

Characterization of a silicon nanowire array using reflected images captured by a smartphone camera

A practical technique for determining the length of a silicon nanowire (SiNW) array is reported by the analysis of reflected images from a smartphone camera. The SiNW array was prepared by electroless chemical etching and its length controlled by the etching time of a Si wafer. The average lengths for the SiNW array were characterized by scanning electron microscopy. The relationship between the reflection spectrum and the length of the SiNW array was investigated. The ratio of percent reflectance from 900 to 550 nm exponentially increased from 1.8 ± 0.1 to 22.2 ± 1.3 when the average length increased from 184 ± 12 to 1237 ± 23 nm. Optical sensing for characterization of the length of SiNW was further developed into a simple and practical technique using a smartphone camera as a detector. A 3D printed tool was assembled to the smartphone to control the light path and the reflected image of the SiNW array was acquired. The reflected intensity ratio obtained from the reflected images with long pass to short pass filters increased analogously to the spectroscopic results. This optical-sensing-based smartphone showed simple and rapid detection for determining the lengths of a SiNW array and a SiNW array coated with a polymer film. This platform is compact and capable of on-site detecting and is promising for the characterization of reflective materials.

Surgical anatomy of basal turn in relation to middle cranial fossa and round window as pertaining to middle fossa cochlear implant technique.

The purpose of this investigation was to evaluate the relation of the basal turn of cochlea with middle cranial fossa and round window as pertaining to middle cranial fossa cochlear implant technique. Fifty-four formalin preserved temporal bones were micro-dissected to expose the basal turn. The point (f) was marked on the basal turn of cochlea where there was minimum distance of basal turn of cochlea from the floor of middle cranial fossa (f1). The f-f1 distance, the angle (∠smf) and distance of point "f" from the round window (s-f) was measured. The mean minimum distance between basal turn of cochlea and floor of middle cranial fossa (f-f1) was 2.0 ± 0.7mm.The point f was at mean distance (s-f) and angle (∠smf) of 14.7 ± 1.6mm and 217° ± 13.7° from round window, respectively. The information may be helpful for designing appropriate electrode array for middle fossa technique especially for deciding the length of electrode array towards round window, as otherwise electrode may extend into vestibule of inner ear. In the cases where bone thickness between superior part of basal turn of cochlea and middle cranial fossa is < 1.5mm, surgeon should be extra cautious.

The rationale for FLEX (cochlear implant) electrode with varying array lengths.

With cochlear implantation (CI) being the standard of care for profoundly deaf cases, more and more patients with low frequency residual hearing are currently being treated with CI. In view of preserving the residual hearing, the ultimate aim of both the surgeons and the CI companies is to achieve zero-degree of electrode insertion trauma. Variations in the size and shape of cochlea, cross-sectional dimensions of ST, electrode insertion techniques with and without metal stylet rod and the experience level of the operating surgeons, all play a role in the electrode array related insertion trauma. An effective electrode design must include flexible array to accommodate the cochlear shape variation, electrode with variety of array lengths to support the concept of cochlear size specific electrode array and finally smaller cross-sectional dimensions of electrode array in matching the cross-sectional dimensions of ST. As per published reports, FLEX electrode array design offers minimal degree of electrode insertion trauma along with the possibility of patient specific electrode array length matching their cochlear size. Looking at the cross-sectional dimensions of FLEX electrode array along with its volume, it appear to be highly safe to the cochlea by not taking too much volume inside the ST. To offer additional support, otological pre-planning software tool like OTOPLAN is now clinically available in measuring the cochlear size in finding the best electrode array match along with the possibilities of anatomy based post-operative speech processor fitting.

Research software in cochlear duct length estimation, Greenwood frequency mapping and CI electrode array length simulation.

Background and objectiveThe size of the cochlea varies a lot among the human population bringing the necessity for electrode arrays to be available in various lengths irrespective of the cochlear implant (CI) brand. This research software helps in the estimation of the patient's cochlear duct length (CDL) which is then used for the simulation of the correct length electrode array matching the patient's cochlear size and as well in getting the patient specific cochlear frequency map.MethodsVisual Studio Express 2012 for Windows Desktop is used in the architecture of this research software. The basal turn diameter of the cochlea (“A” value) needs to be measured from the pre-operative computed tomography (CT) image of the patient's temporal bone. This “A” will be taken as the input for the CDL equations proposed by Alexiades et al for estimating the CDL along the basilar membrane for various insertion depths. Greenwood's equation is then used in combination with the CDL for the full length of the cochlea in getting the patient specific frequency map.ResultsThe research software with the help of the “A” value as input, with few button clicks, gives the patient specific CDL for various insertion depths and the Greenwood's frequency map. The users have the choice to select any electrode array of their choice and place it under the frequency map to see how good it fits to that particular patient's cochlea. Also, given the possibility to drag and move the electrode array picture to mimic the post-operative actual electrode insertion depth.ConclusionsThis research software simplifies the overall process of CDL estimation and in getting the patient specific cochlear frequency map. The clinicians get the chance to simulate placing the various electrode array lengths in patient cochlea in identifying the best fit electrode. This could help in pushing the CI field into the concept of individualized CI electrode array solution that ultimately benefits the patients.

Analysis of Modified Shell Sort for Fully Homomorphic Encryption

The Shell sort algorithm is one of the most practically effective in-place sorting algorithms. However, it is difficult to execute this algorithm with its intended running time complexity on data encrypted using fully homomorphic encryption (FHE), because the insertion sort in Shell sort has to be performed by considering the worst-case input data. In this paper, in order for the sorting algorithm to be used on the FHE data, we modify the Shell sort with an additional parameter α, allowing exponentially small sorting failure probability. For a gap sequence of powers of two, the modified Shell sort with input array length n is found to have the trade-off between the running time complexity of O(n3/2√α+loglogn) and the sorting failure probability of 2-α. Its running time complexity is close to the intended running time complexity of O(n3/2) and the sorting failure probability can be made very low with slightly increased running time. Further, the near-optimal window length of the modified Shell sort is also derived via convex optimization. The proposed analysis of the modified Shell sort is numerically confirmed by using randomly generated arrays. For the practical aspect, our modification can be applied to any gap sequence, and we show that Ciura’s gap sequence, which is known to have good practical performance, is also practically effective when our modified Shell sort is applied. We compare our modified Shell sort with other sorting algorithms with the FHE over the torus (TFHE) library, and it is shown that this modified Shell sort has the best performance in running time among in-place sorting algorithms on homomorphic encryption scheme.

Analysis of Subtelomeric REXTAL Assemblies Using QUAST.

Genomic regions of high segmental duplication content and/or structural variation have led to gaps and misassemblies in the human reference sequence, and are refractory to assembly from whole-genome short-read datasets. Human subtelomere regions are highly enriched in both segmental duplication content and structural variations, and as a consequence are both impossible to assemble accurately and highly variable from individual to individual. Recently, we developed a pipeline for improved region-specific assembly called Regional Extension of Assemblies Using Linked-Reads (REXTAL). In this study, we evaluate REXTAL and genome-wide assembly (Supernova) approaches on 10X Genomics linked-reads data sets partitioned and barcoded using the Gel Bead in Emulsion (GEM) microfluidic method. Our results describe the accuracy and relative performance of these two approaches using the reference-based assessment module of QUAST. We show that REXTAL dramatically outperforms the Supernova whole genome assembler in subtelomeric segmental duplication regions, and results in highly accurate assemblies. Nearly all of the REXTAL "misassemblies" identified using default QUAST parameters simply pinpoint locations of tandem repeat arrays in the reference sequence where the repeat array length differs from that in the cognate REXTAL assembly by 1000 bp.

Performance of defected ground structure with miniaturized microstrip patch antenna using RMPA substrate material

Abstract A parallel structural antenna with the acts slot configuration is indicated for process of 5G wireless technology. The direct slot configuration defined within the patch antenna drives the 5G mid band and twin band frequency reaction in the frequency location without the conditions. Next, a 2-D Double Periodic Electronic Band (EBG) shape is carried out below the metal ground aircraft to request an extended impedance bandwidth for RMPA Materials. The slot duration and feature changed into designed for an impedance bandwidth of 12.49% and 4.49% at three pass band frequencies of 532 GHz and, 835 GHz respectively. Simulated with measured gain and reflection coefficient of correct settlement for bending bandwidths. The antenna array length is 33.5 mm × 33.5 mm. The antenna modified structure and the experimental effects were compared with all the other existing systems. The proposed antenna, which makes use of the EBG structure, suggests pics and excessive sensitivity steady with a massive impedance bandwidth, meeting the necessities of the IoT software program supplied with the resource of 5G technology.

A new feeding topology with internal 180° phase reversal for wideband series‐fed slot array antennas

AbstractThis paper proposes a new feeding topology with internal 180° phase reversal for wideband series‐fed slot array antennas. As a demonstration, a serial fed, half‐wavelength separated, 7‐element array is designed at 5.8 GHz. Comparing with conventional series‐fed arrays, which require one‐wavelength separation, the phase difference between adjacent elements varies less with frequency. Thus, the proposed array has more stable beam pointing and wider 1 dB gain bandwidth. A prototype was fabricated and measured to validate the performance of the feeding topology. A wide operating bandwidth of 22.4% for S11 &lt; −10 dB, a 1 dB gain bandwidth of 14% and bi‐directional peak gain of 10.01 dBi are achieved with the array length of 2.7λ0. The proposed feeding topology shows its potentials in realizing signal coverage on some special occasions, such as coal mines and tunnels.

Design of an ultra-compact low-crosstalk sinusoidal silicon waveguide array for optical phased array.

In this work, an ultra-compact low-crosstalk sinusoidal silicon waveguide array is proposed and analyzed. We first design a pair of low-crosstalk sinusoidal silicon waveguides with a pitch of 695 nm, where the sinusoidal bends are the key to reduce the crosstalk between waveguides. Then, based on this idea, we propose a low-crosstalk sinusoidal silicon waveguide array with a 695 nm pitch. The simulation results show that for an array length of 100 µm, the insertion loss is as low as 0.08 dB, and the crosstalk is lower than -26 dB at 1550 nm. The 695 nm pitch waveguide array also exhibits a favorable fabrication error tolerance when taking into account the waveguide width variations in practice. Moreover, within the acceptable range of crosstalk, the center-to-center distance between adjacent waveguides of this array can be further reduced to 615 nm. Since the pitch is related to the power consumption and beam-steering range of the optical phased array, our design provides an effective method to build the emitter for an energy-efficient optical phased array with a large field of view.

A critical insight into the influence of data acquisition parameters on the dispersion imaging in passive roadside MASW survey

Passive roadside method of multichannel analysis of surface wave (MASW) is a simple passive technique of subsurface exploration that can provide deeper subsoil investigation compared to conventional active MASW technique. However, attributed to the lack of thorough experimental validation with other techniques and establishment of various acquisition parameters, the number of real world applications of the method is scanty. The paper presents the results of extensive experimentation to highlight the importance of two primary acquisition parameters, namely the length of receiver array and acquisition time, on the dispersion imaging of roadside survey at sites comprising different traffic volume. The length of receiver array directly affects the resolution of dispersion image and the estimated depth of shear-wave velocity profile. Thicker energy band and poor resolution in the lower frequency band of dispersion image are found to be the outcome of utilizing smaller arrays. The span of acquisition time is a site dependent parameter and is governed by the volume of the traffic and number of existing sources on the road surface nearby the test site. Comparatively smaller recording time is found effective in producing dispersion images with sufficient resolution in a heavier traffic volume case. The paper also illustrates a detailed comparison of results obtained from roadside and active survey in terms of the dispersion imaging and shear wave velocity profiles at the specific sites.

Radiological evaluation of a new straight electrode array compared to its precursors

ObjectiveThe aim of this study is to examine electrode array coverage, scalar position and dislocation rate in straight electrode arrays with special focus on a new electrode array with 26 mm in lengths.Study designRetrospective study.SettingTertiary academic center.Patients201 ears implanted between 2013 and 2019.Main outcome measuresWe conducted a comparative analysis of patients implanted with lateral wall electrode arrays of different lengths (F24 = MED-EL Flex24, F26 = MED-EL Flex26, F28 = MED-EL Flex28 and F31.5 = MED-EL FlexSoft). Cone beam computed tomography was used to determine electrode array position (scala tympani (ST) versus scala vestibuli (SV), intracochlear dislocation, position of dislocation and insertion angle).ResultsStudy groups show no significant differences regarding cochlear size which excludes influences by cochlear morphology. As expected, the F24 showed significant shorter insertion angles compared to the longer electrode arrays. The F26 electrode array showed no signs of dislocation or SV insertion. The electrode array with the highest rate of ST dislocations was the F31.5 (26.3%). The electrode array with the highest rates of SV insertions was the F28 (5.75%). Most of the included electrode arrays dislocate between 320° and 360° (mean: 346.4°; range from 166° to 502°).ConclusionThe shorter F24 and the new straight electrode array F26 show less or no signs of scalar dislocation, neither for round window nor for cochleostomy insertion than the longer F28 and the F31.5 array. As expected, the cochlear coverage is increasing with length of the electrode array itself but with growing risk for scalar dislocation and with the highest rates of dislocation for the longest electrode array F31.5. Position of intracochlear dislocation is in the apical cochlear part in the included lateral wall electrode arrays.

Taper Design for Active Arrays With Maximized EIRP for Bounded Sidelobe Level

Tapering an active array antenna system on transmit lowers the sidelobe level, but it adversely affects equivalent isotropically radiated power (EIRP) by reducing both power and gain. In this article, we analyze this effect. First, we propose a new taper efficiency coefficient, which allows us to assess the effect of tapering on EIRP (in contrast to the standard taper efficiency that describes the effect of tapering on gain only). Then, we present an optimization method to compute the taper weights that maximize the defined efficiency for an assumed bound on the sidelobe level. The obtained optimal weights can be used not only to taper an antenna array but also as a benchmark for other tapers. Therefore, we analyze several known tapers and compare their transmit efficiencies. As a result, we find that for some combinations of sidelobe level and array length, the proposed optimal taper provides substantially better efficiency than Dolph-Chebyshev or Taylor tapers.

Antenna Selection for Improving Energy Efficiency in XL-MIMO Systems

We consider the recently proposed extra-large scale massive multiple-input multiple-output (XL-MIMO) systems, with some hundreds of antennas serving a smaller number of users. Since the array length is of the same order as the distance to the users, the long-term fading coefficients of a given user vary with the different antennas at the base station (BS). Thus, the signal transmitted by some antennas might reach the user with much more power than that transmitted by some others. From a green perspective, it is not effective to simultaneously activate hundreds or even thousands of antennas, since the power-hungry radio frequency (RF) chains of the active antennas increase significantly the total energy consumption. Besides, a larger number of selected antennas increases the power required by linear processing, such as precoding matrix computation, and short-term channel estimation. In this paper, we propose four antenna selection (AS) approaches to be deployed in XL-MIMO systems aiming at maximizing the total energy efficiency (EE). Besides, employing some simplifying assumptions, we derive a closed-form analytical expression for the EE of the XL-MIMO system, and propose a straightforward iterative method to determine the optimal number of selected antennas able to maximize it. The proposed AS schemes are based solely on long-term fading parameters, thus, the selected antennas set remains valid for a relatively large time/frequency intervals. Comparing the results, we find that the genetic-algorithm based AS scheme usually achieves the best EE performance, although our proposed highest normalized received power AS scheme also achieves very promising EE performance in a simple and straightforward way.

Frequency-to-Place Mismatch: Characterizing Variability and the Influence on Speech Perception Outcomes in Cochlear Implant Recipients.

The spatial position of a cochlear implant (CI) electrode array affects the spectral cues provided to the recipient. Differences in cochlear size and array length lead to substantial variability in angular insertion depth (AID) across and within array types. For CI-alone users, the variability in AID results in varying degrees of frequency-to-place mismatch between the default electric frequency filters and cochlear place of stimulation. For electric-acoustic stimulation (EAS) users, default electric frequency filters also vary as a function of residual acoustic hearing in the implanted ear. The present study aimed to (1) investigate variability in AID associated with lateral wall arrays, (2) determine the subsequent frequency-to-place mismatch for CI-alone and EAS users mapped with default frequency filters, and (3) examine the relationship between early speech perception for CI-alone users and two aspects of electrode position: frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with spectral selectivity at the periphery. One hundred one adult CI recipients (111 ears) with MED-EL Flex24 (24 mm), Flex28 (28 mm), and FlexSOFT/Standard (31.5 mm) arrays underwent postoperative computed tomography to determine AID. A subsequent comparison was made between AID, predicted spiral ganglion place frequencies, and the default frequency filters for CI-alone (n = 84) and EAS users (n = 27). For CI-alone users with complete insertions who listened with maps fit with the default frequency filters (n = 48), frequency-to-place mismatch was quantified at 1500 Hz and angular separation between neighboring contacts was determined for electrodes in the 1 to 2 kHz region. Multiple linear regression was used to examine how frequency-to-place mismatch and angular separation of contacts influence consonant-nucleus-consonant (CNC) scores through 6 months postactivation. For CI recipients with complete insertions (n = 106, 95.5%), the AID (mean ± standard deviation) of the most apical contact was 428° ± 34.3° for Flex24 (n = 11), 558° ± 65.4° for Flex28 (n = 48), and 636° ± 42.9° for FlexSOFT/Standard (n = 47) arrays. For CI-alone users, default frequency filters aligned closely with the spiral ganglion map for deeply inserted lateral wall arrays. For EAS users, default frequency filters produced a range of mismatches; absolute deviations of ≤ 6 semitones occurred in only 37% of cases. Participants with shallow insertions and minimal or no residual hearing experienced the greatest mismatch. For CI-alone users, both smaller frequency-to-place mismatch and greater angular separation between contacts were associated with better CNC scores during the initial 6 months of device use. There is significant variability in frequency-to-place mismatch among CI-alone and EAS users with default frequency filters, even between individuals implanted with the same array. When using default frequency filters, mismatch can be minimized with longer lateral wall arrays and insertion depths that meet the edge frequency associated with residual hearing for CI-alone and EAS users, respectively. Smaller degrees of frequency-to-place mismatch and decreased peripheral masking due to more widely spaced contacts may independently support better speech perception with longer lateral wall arrays in CI-alone users.

Formation of one-dimensional arrays of nanoparticles using segmented polyurethane nanofibers prepared by electrospinning

The number density and the arrangement of metal nanoparticles in composite materials have a significant effect on their performance and hence their suitability for use in sensors and devices. Forming one-dimensional arrays of metal nanoparticles is one way of controlling their number density and arrangement in the devices. In this study, we fabricated one-dimensional arrays of gold nanoparticles by adsorbing them on linearly distributed hard segments present on the surfaces of segmented polyurethane nanofibers, which were produced by electrospinning under a stretching force. The length of the one-dimensional array was approximately 500 nm. Furthermore, the interparticle distance was almost constant at approximately 14 nm. Thus, the proposed method is suitable for fabricating one-dimensional arrays of metal nanoparticles with high precision.