Pair Of Rods Research Articles

A multichannel closed bipolar platform to visual electrochemiluminescence sensing of caffeic acid as a model: Potential for multiplex detection

In this study, a fully-featured electrochemiluminescence (ECL) sensing platform based on a multichannel closed bipolar system (closed-BP, C-BP) for the determination of caffeic acid (CA) was successfully developed. The system comprises three individual reservoirs connected to each other by two pairs of gold rods as bipolar electrodes. Moreover, a single pair of gold rods functions as the driving electrodes. Due to configuration consisting of three channels and double-bipolar electrodes, the detection of CA was accomplished in two oxidation and reduction pathways within a single device. Firstly, through close observation of the reactions occurring within the device and utilizing a universal pH indicator and bipolar electrodes, a precise mechanism for the current bipolar systems was initially proposed. Then, the concentration of CA was monitored in the reporting chamber through the following ECL intensities resulting from luminol oxidation and H2O2. The monitoring process was performed using both a photomultiplier tube (PMT) and a digital camera. In the process of analyte oxidation, the PMT and visual (camera)-based detection exhibited a linear response from 5 μmol L−1 to 700 μmol L−1 (limit of detection (LOD) 1.2 μmol L−1) and 50 μmol L−1 to 600 μmol L−1 (LOD 14.8 μmol L−1), respectively. In the analyte reduction pathway, the respective values were 30 μmol L−1 to 450 μmol L−1 (LOD 8.6 μmol L−1) and 55 μmol L−1 to 400 μmol L−1 (LOD 21.2 μmol L−1), for the PMT and visual-based detection, respectively. Our experiments have demonstrated the practical application of the sensor array for efficient and high-performance analysis. This innovative design holds significant potential for diverse fields and paves the way for the development of a user-friendly device.

Bistability in the wake of a circular cylinder with passive control using two leeward rods

This paper presents an experimental investigation on the flow around a circular cylinder controlled by a pair of rods placed close to the separated shear layers from the leeward face of the cylinder. Past research of Cicolin et al. (2021) has shown that one control rod, placed at specific positions, induces a late flow separation on the main cylinder’s surface in a typical occurrence of the Coandă effect. As a result the control rod reduced the mean drag acting on the cylinder but also produced a net mean lift force. We now present an extension of the aforementioned study to consideration of a pair of symmetrically arranged control rods, aimed at eliminating the mean lift force whilst maintaining a drag reduction. The experiments were carried out at a Reynolds number Re=20,000 based on the diameter of the main cylinder D, with the diameter of the control rods being ten times smaller than that of the cylinder. The centre-to-centre distances between each control rod and the cylinder was 0.7D, and the angular position of the rods varied from θ=120∘ to 125∘, where θ is measured from the front stagnation point. Time-resolved PIV velocity fields and hydrodynamic forces were measured for the different setups. Results show that the mean flow is asymmetric in spite of the symmetry of the geometric model and position of the rods. The pair of control rods induces a bistable flow, induced by the imbalance of two colliding jets in the near wake. The dynamics were found to be random, with the average switching time between stable states depending on the position of the rods. The mean drag force was reduced by up to 15%, and the mean lift force was reduced by 80% compared to the cases with a single control rod. It was also observed that the control rod can induce two different types of flow separation from the main cylinder, one in which the flow separates from the main cylinder only once and one in which a small separation bubble forms in proximity to the control rod before reattaching and then permanently separating. These distinct features play an important role in the dynamics of the bistability and hint at a possible extension of the total drag reduction to 30% if the bistability is suppressed.

Optimization of a Digital Mass Filter for the Isolation of Intact Protein Complexes in Stability Zone 1,1.

Digital mass filters are advantageous for the analysis of large molecules due to the ability to perform ion isolation of high-m/z ions without the generation of very high radio frequency (RF) and DC voltages. Experimentally determined Mathieu stability diagrams of stability zone 1,1 for capacitively coupled digital waveforms show a voltage offset between the quadrupole rod pairs is introduced by the capacitors which is dependent on the voltage magnitude of the waveform and the duty cycle. This changes the ion's a value from a = 0 to a < 0. These effects are illustrated for isolation for single-charge states for various protein complexes up to 800 kDa (GroEL) for stability zone 1,1. Isolation resolving power (m/Δm) of approximately 280 was achieved for an ion of m/z 12,315 (z = 65+ for 800.5 kDa GroEL D398A), which corresponds to an m/z window of 44.

Method of the Protected Volume LPZ0B of Lightning Air-Termination Systems

The protection system for the structures against lightning is basically constituted by means of an air termination system, down-conductors and a ground-termination system. The IEC standard 62305 introduces the rolling sphere method to analyze and to design the protected volumes of air-termination systems with a complex configuration. In order to avoid the exposure of equipment and elements on the building roof to direct lightning in the design and the following operation with new exigencies, the identification of the protected volumes LPZ0B allows taking corrective measures if needed. The suggested method assumes as reference element a pair of rods for the air termination system and proposes to identify the protected volume combining the two IEC methods of the graphical rolling sphere with the protective angle. The protected volume method proposes, as simpler first step, the mathematical calculation of the minimum protection height of prospected profile described by the rolling sphere, useful for a preliminary evaluation. As second step, the method completes the definition of the protected volume section, describing a cautionary model that replaces the circular sector of the rolling sphere with a “vase section” shape, applying the protective angle method.

Control of vortex-induced vibration of an elastically mounted cylinder with a pair of porous rods

In this work, the control of vortex-induced vibration (VIV) of an elastically mounted cylinder with a pair of porous rods is numerically investigated at a Reynolds number of 150. To calculate the forces on the moving porous media, an efficient formula based on the momentum theorem is proposed. The porous rods are placed behind the cylinder at an angle of 25°, and the effects of the gap ratio (G) and permeability of the porous rods (Da) on the VIV are studied in detail. Based on the results obtained, it is found that at small G, the VIV is suppressed mainly through the action of shear-layer separation and reattachment. In addition, better performance of VIV control can be achieved by using porous rods with lower Da. As G increases, the porous rods maintain good performance, while solid rods enhance the vibration, the latter being caused by the interaction between the vortices shed from the main cylinder and the rods. The best control effect is achieved by using porous rods at Da = 0.0001 and G = 0.7. The corresponding reductions of vibration amplitude, drag force, and lift force are 85%, 33%, and 84%, respectively.

Abundant exact solutions for the deoxyribonucleic acid (DNA) model

In this study, the improved [Formula: see text] expansion method and Exp[Formula: see text] function method are used to construct the newly closed-form exact solutions for the deoxyribonucleic acid (DNA) model which includes hyperbolic, trigonometric and exponential solutions. These solutions include a wealth of information regarding the dynamical behavior of homogeneous long elastic rods with circular cross-sections. These rods comprise a pair of polynucleotide rods of the DNA molecule that are connected by an elastic diaphragm, demonstrating the involvement of the hydrogen bond in this communication. The performance of these approaches demonstrates their use and efficacy in solving a variety of nonlinear evolution problems of integer and fractional order. The physical significance of the established and the obtained solutions has been shown via 3D shapes. It is worth noting that the solutions obtained here via the proposed schemes are more generalized and can be helpful to demonstrate the internal interaction of the DNA model arising in mathematical biology. The proposed method has been used to obtain exact traveling wave solutions for fraction nonlinear partial differential equations (NPDEs) arising in nonlinear sciences.

Distinct regulatory states control the elongation of individual skeletal rods in the sea urchin embryo.

BackgroundUnderstanding how gene regulatory networks (GRNs) control developmental progression is a key to the mechanistic understanding of morphogenesis. The sea urchin larval skeletogenesis provides an excellent platform to tackle this question. In the early stages of sea urchin skeletogenesis, skeletogenic genes are uniformly expressed in the skeletogenic lineage. Yet, during skeletal elongation, skeletogenic genes are expressed in distinct spatial sub‐domains. The regulation of differential gene expression during late skeletogenesis is not well understood.ResultsHere we reveal the dynamic expression of the skeletogenic regulatory genes that define a specific regulatory state for each pair of skeletal rods, in the sea urchin Paracentrotus lividus. The vascular endothelial growth factor (VEGF) signaling, essential for skeleton formation, specifically controls the migration of cells that form the postoral and distal anterolateral skeletogenic rods. VEGF signaling also controls the expression of regulatory genes in cells at the tips of the postoral rods, including the transcription factors Pitx1 and MyoD1. Pitx1 activity is required for normal skeletal elongation and for the expression of some of VEGF target genes.ConclusionsOur study illuminates the fine‐tuning of the regulatory system during the transition from early to late skeletogenesis that gives rise to rod‐specific regulatory states.

Nonadditive drag of tandem rods drafting in granular sediments.

We examine the drag experienced by a pair of vertical rods moving in tandem through a granular bed immersed in a fluid as a function of their separation distance and speed. As in Newtonian fluids, the net drag experienced by the rods initially increases with distance from the value for a single rod before plateauing to twice the value. However, the drag acting on the two rods is remarkably different, with the leading rod experiencing roughly similar drag compared to a solitary rod, while the following rod experiences far less drag. The anomalous relationship of drag and the distance between the leading and following body is observed in both dry granular beds and while immersed in viscous Newtonian fluids across the quasistatic and the rate-dependent regimes. Through refractive index matching, we visualize the sediment flow past the two rods and show that a stagnant region develops in their reference frame between the rods for small separations. Thus, the following rod is increasingly shielded from the granular flow with decreasing separation distance, leading to a lower net drag. Care should be exercised in applying resistive force theory to multicomponent objects moving in granular sediments based on our result that drag is not additive at short separation distances.

Ion transmission probability through quadrupole mass filter depending on initial ion condition and rod misalignment

A quadrupole mass filter consists of four equidistant parallel rods. Each opposing rod pair is connected electrically, and direct current (DC) and radio frequency alternating current (AC) potentials are applied between one pair of rods and the other. For specific combinations of AC and DC potentials, only ions with a particular mass-to-charge ratio will have a stable trajectory and pass through the quadrupole. Other ions collide with the rods and are not transmitted. The mass filtering is entirely based on the stability of the trajectory of the ions inside the quadrupole. Despite its simple physical geometry and obvious mass separating principle, it is very difficult to analyze the ion behavior in the device even if there is a small deviation from ideal operating conditions. In this paper, the ion transmission probabilities through a quadrupole were calculated using computer simulation at various initial ion conditions and quadrupole mechanical misalignment. The results of this study mainly show the allowable error for quadrupole design, which can be used in improving the performance of the quadrupole mass filter.

Cyclic Shear Performance of Reinforced Concrete Columns Strengthened by External Steel Rods

This study presents a strengthening method for reinforced concrete (RC) columns. The proposed method, which consists of a pair of steel rods, two reverse-threaded couplers, and four corner blocks, is feasible and straightforward. A quasi-static cyclic loading test was performed on the columns externally strengthened by the steel rods. It was found that the corner blocks and the external steel rods with a low prestress level effectively confined the concrete on the compression side of plastic hinges, which eventually induced flexural failure with a ductility higher than three in the strengthened columns. In addition, an analytical approach to predict the shear strength and ultimate flexural strength of the externally strengthened columns was applied. The comparison of analytical and experimental results showed that the analytical approach provided highly accurate predictions on the maximum strength and the failure mode of the externally strengthened columns. It is expected that the application of the proposed method will improve the seismic performance of damaged or deteriorated RC structures, thereby increasing their lifespan expectancy and sustainability.

Is there still a place for malleable penile implants in the United States? Wilson's Workshop #18.

The use of semirigid rod penile prosthesis for the management of erectile dysfunction was first described over 85 years ago. Since then, there have been numerous design advancements leading to improved overall durability, concealability, rigidity, and natural feel. However, the inflatable penile prosthesis (IPP) still has a higher patient satisfaction rate and is currently the most commonly inserted prostheses in the United States. There are still certain situations and conditions where the simplicity of a rod may be preferred over an IPP. A pair of semirigid rods has been shown to have less risk of malfunction and need for revision surgery. In addition, patients with poor manual dexterity, those undergoing a salvage for infection prosthesis and those with a prolonged (> 48 h) priapic episode may be better served with a rod than an IPP. Finally, in patients compromised by infection or priapism, the rods can later successfully be exchanged for an IPP with potentially longer, wider cylinders with resultant greater patient satisfaction.

Обгрунтування конструктивних особливостей та кінематичний аналіз руху гичкоочисної машини

Зниження собівартості цукрової сировини поряд з підвищенням її якості дозволить підтримувати та підвищити конкурентноспроможність українських виробників цукру на міжнародному рівні, а також будуть створені передумови для зниження вартості кінцевого продукту на внутрішньому ринку. Одним із шляхів досягнення такої мети виступає застосування таких технічних рішень під час виробництва сировини які забезпечать зниження затрат праці та енергоємність процесів виробництва.В статті запропоновано конструкцію трирядної навісної машини призначеної для зрізування, подрібнення та розкидання по ширині захвату гички цукрових буряків, очищення залишків гички комбінованими та еластичними робочими органами, причому еластичні робочі органи закріплені на паралелограмному копіювальному механізмі та обертаються в протилежну сторону відносно зрізуючих. Робочі вали машини розміщені паралельно рядкам посівів культури, а робочі органи закріплені перпендикулярно. Зріз і подрібнення гички проводиться г-подібними ножами розміщеними попереду на висоті вищій за ріст коренеплодів. Після чого, комбінованим очисником, який складається з пари жорстких прутків встановлених на пружній підвісці та U-подібного еластичного бича, проводиться очищення залишків гички. Жорсткі прутки застосовуються з метою підняття і обриву полеглої та сухої гички та розбивання жмутка залишків гички на голівці коренеплоду, а пружна підвіска забезпечує таке прикладене зусилля, яке непошкодить тіло кореня. Еластичний очисник проводить послідуюче зчісування залишків гички з голівки коренеплоду. Доочисний пристрій встановлений під кутом до напрямку руху машини на паралелограмному копіювальному механізмі з регулювально-опорними полозами, а також встановлено привідний механізм зміни напряму обертання валів доочисника. Доочисник являє собою батарею набраних еластичних бичів.Проведено кінематичний аналіз руху машини та паралелограмного копіювального механізму. Отримано коефіцієнт кінематичного режиму роботи очисника з віссю обертання паралельною до напрямку переносної поступальної швидкості та рівняння шляху вертикального переміщення точок даного механізму з регулювально-опорним полозом в залежності від часу.Результатом дослідження є визначенні перспективи вдосконалення технології очищення гички цукрових буряків, запропоновано нову конструкцію очисної машини та проведено кінематичний аналіз паралелограмного копіювального механізму з регулювально-опорними полозами.

Performance improvement of aeroelastic energy harvesters with two symmetrical fin-shaped rods

The characteristics of a piezoelectric aeroelastic energy harvester with a pair of fin-shaped rods (FSR) symmetrically fixed on the circular cylinder surface are experimentally investigated. The circumferential location of FSR is defined by the placement angle which is measured from the front stagnation point of cylinder to the upstream edge of FSR. The placement angle ranges from 0° to ±150° and the coverage of one rod is equivalent to 30°. The experimental results show that the optimal placement angles of FSR are 30°–60° where synchronization region of the vibrational cylinder can be obviously expanded. The maximum harvested power can reach 998 ​μW which is 25.5 times as high as that of a smooth circular cylinder. Moreover, the wind speed range which can be utilized for energy harvesting is significantly broadened. The aeroelastic energy harvester can harness wind energy as slow as 1.0 ​m/s and can continuously harvest energy when the wind speed beyond critical value.

Can you use a coconut to find groundwater?

Divining has been used for centuries for groundwater and mineral prospecting. Historically, divining has been reliant on a rod, or pair of rods, accompanied by a particular individual. Recently, th...

A sensitive detection of high Rydberg atom with large dipole moment**Project supported by the National Natural Science Foundation of China (Grant Nos. 91421305, 91121005, and 11674359) and the National Key Basic Research Program of China (Grant No. 2013CB922003).

We report a sensitive detection of high Rydberg atom with large dipole moment utilizing its deflection near a pair of parallel cylindrical copper rods which are oppositely charged. When the low-field seeking state Rydberg atoms fly across the gradient electric field formed by the pair of rods, they will be pushed away from the rods while the high-field seeking state ones will be attracted towards the rods. These atoms will form different patterns on an ion imaging system placed downwards at the end of the rods. The spatial distribution of the deflected atoms on the imaging system is also simulated, in good agreement with the experimental results, from which we can deduce the quantum state information of the excited atoms. This state resolvable Rydberg atom detection can be used for the dynamics research of the dipole–dipole interaction between atoms with large dipole moments.

Vortex-induced vibrations of a circular cylinder with a pair of control rods of varying size

We present an experimental study on the vortex-induced vibration (VIV) of a low mass-damping one-degree-of-freedom circular cylinder subject to uniform cross-flow, with pairs of control rods of varying size located in its wake. Two particular locations for control rods, selected according to recent experimental maps of VIV sensitivity to localized perturbations, have been tested for increasing control rod diameters, d. Important amplitude reductions are observed for all arrangements investigated, with nearly total suppression of oscillations (up to 90%) for control rods of d = 0.4D, where D is the diameter of the main cylinder. Force measurements have been used to describe the nature of changes observed in the wake and the mechanisms behind the VIV control. In general, the placement of control rod pairs in the near wake leads to an important weakening of the lift coefficient and alters substantially the phase between transverse force and cylinder displacement. Moreover, it is shown that, for some particular arrangements, attenuation of VIV is obtained along with a drag reduction of approximately 60% at the upper branch of amplitude response, rendering the present strategy an interesting and practical solution for VIV control when several cylinders need to be installed together.

Design of High Power Handling Filter Using Cascaded Quadruplet Superconducting Bulk Resonators

We designed transmit bandpass filters that have a four-pole cascaded quadruplet (CQ) structure with high-temperature superconducting (HTS) bulk disk resonators. We developed a trimming device that can change the electric-coupling coefficients simply by adjusting the height of a pair of copper rods. We analyzed the frequency response of the filters using an electromagnetic simulator and found that the trimming device can provide the targeted value for the coupling coefficient. In addition, from simulation of the filters, we obtained frequency responses with a center frequency of 5.04 GHz, a bandwidth of 124 MHz, and a skirt characteristic of 3.23 dB/5 MHz. To our knowledge, this is the first CQ filter structure yet developed using HTS disk resonators and a trimming system for electric coupling.

Asynchronous oscillations of rigid rods drive viscous fluid to swirl

Stokes flow is generated by repeatedly oscillating a pair of rigid rods. Table-top experiments and simulations reveal that a simple phase delay gives rise to complex flow patterns.

Effects of an applied voltage on direct interspecies electron transfer via conductive materials for methane production

Direct interspecies electron transfer (DIET) between exoelectrogenic bacteria and methanogenic archaea via conductive materials is reported as an efficient method to produce methane in anaerobic organic waste digestion. A voltage can be applied to the conductive materials to accelerate the DIET between two groups of microorganisms to produce methane. To evaluate this hypothesis, two sets of anaerobic serum bottles with and without applied voltage were used with a pair of graphite rods as conductive materials to facilitate DIET. Initially, the methane production rate was similar between the two sets of serum bottles, and later the serum bottles with an applied voltage of 0.39V showed a 168% higher methane production rate than serum bottles without an applied voltage. In cyclic voltammograms, the characteristic redox peaks for hydrogen and acetate oxidation were identified in the serum bottles with an applied voltage. In the microbial community analyses, hydrogenotrophic methanogens (e.g. Methanobacterium) were observed to be abundant in serum bottles with an applied voltage, while methanogens utilizing carbon dioxide (e.g., Methanosaeta and Methanosarcina) were dominant in serum bottles without an applied voltage. Taken together, the applied voltage on conductive materials might not be effective to promote DIET in methane production. Instead, it appeared to generate a condition for hydrogenotrophic methanogenesis.

Reversible Nonlinear Energy Harvester Tuned by Tilting and Enhanced by Nonlinear Circuits

Nonlinear vibration is capable of effectively extending the frequency bandwidth of energy harvesters. Either hardening or softening nonlinearity has been used in various designs to achieve broad-bandwidth energy harvesting. In this paper, we propose a new method to achieve reversible hysteretic responses, i.e., both hardening and softening nonlinear responses, mechanically without additional magnetic interactions. This tunable nonlinearity endows energy harvesters with a great adaptability to environment. The proposed energy harvester is composed of a flexural center and two mass blocks, supported by a pair of elastic rods that are fixed on a vibration base. Different nonlinear responses are invoked by tilting the fixed–fixed elastic rods at different angles. A lumped-parameter model is developed to simulate the nonlinear electromechanical coupling system, and that is analytically solved by virtue of the high-order perturbation technique. The dynamic responses under different frequencies and accelerations are analytically characterized and compared well with the experimental data measured from a fabricated prototype. Furthermore, a nonlinear conditioning circuit (self-powered series synchronized switch harvesting on inductor) is constructed and tested with the proposed nonlinear energy harvester, with which the performance is enhanced about 200% for both resistive loads and capacitive loads.