Bridge Configuration Research Articles

A monolithically integrated microcantilever biosensor based on partially depleted SOI CMOS technology

This paper presents a monolithically integrated aptasensor composed of a piezoresistive microcantilever array and an on-chip signal processing circuit. Twelve microcantilevers, each of them embedded with a piezoresistor, form three sensors in a Wheatstone bridge configuration. The on-chip signal processing circuit consists of a multiplexer, a chopper instrumentation amplifier, a low-pass filter, a sigma-delta analog-to-digital converter, and a serial peripheral interface. Both the microcantilever array and the on-chip signal processing circuit were fabricated on the single-crystalline silicon device layer of a silicon-on-insulator (SOI) wafer with partially depleted (PD) CMOS technology followed by three micromachining processes. The integrated microcantilever sensor makes full use of the high gauge factor of single-crystalline silicon to achieve low parasitic, latch-up, and leakage current in the PD-SOI CMOS. A measured deflection sensitivity of 0.98 × 10−6 nm−1 and an output voltage fluctuation of less than 1 μV were obtained for the integrated microcantilever. A maximum gain of 134.97 and an input offset current of only 0.623 nA were acquired for the on-chip signal processing circuit. By functionalizing the measurement microcantilevers with a biotin-avidin system method, human IgG, abrin, and staphylococcus enterotoxin B (SEB) were detected at a limit of detection (LOD) of 48 pg/mL. Moreover, multichannel detection of the three integrated microcantilever aptasensors was also verified by detecting SEB. All these experimental results indicate that the design and process of monolithically integrated microcantilevers can meet the requirements of high-sensitivity detection of biomolecules.

Fault identification scheme for solar photovoltaic array in bridge and honeycomb configuration

Fault identification scheme for solar photovoltaic array in bridge and honeycomb configuration

Life-cycle seismic resilience assessment of isolated bridges equipped with different isolation systems

Damage to bridges during a seismic event can cause significant disruption to post-event activities. In addition to natural hazards, the deterioration of bridges over their lifespan also significantly impacts seismic performance. This study intends to evaluate the overall life-cycle resilience performance and post-seismic loss analysis of bridges equipped with two different isolation systems including lead rubber bearings and friction pendulum bearings. Two different bridge configurations and three different suites of earthquakes representing possible seismic hazards at the bridge site are considered. The comparative resilience assessment and cost analysis represent the base-isolation technique’s adequacy, effectiveness and cost-effectiveness. Statistical analysis is conducted to identify the parameters affecting the seismic resiliency, loss and cost analysis of base-isolated bridges. The results show that seismic resilience, loss and cost analysis are more sensitive to the type of ground motions, geometric shape of the bridge and type of isolation bearings, respectively.

An Efficient Design of the Piezoresistive Pressure Sensor Applied for Micro Aerial Vehicle

In this research, the developing process of a piezoresistive pressure sensor working in the atmosphere environment applied in micro aerial vehicle using the MEMS fabrication method is introduced. The sensor consists of four Au/Cr piezoresistors in a Wheatstone bridge configuration on a wet oxidized silicon diaphragm. To fabricate the sensor, three lithographic steps were conducted: the first one is to define the resistors and Au/Cr lines/pads, the second and the third ones are to determine the width and the thickness of the square SiO2/Si diaphragm, respectively. The sensor diaphragm shape and thickness were defined by the anisotropic etching of Si in tetramethylammonium hydroxide (TMAH) solution, and the resistors array are formed by sputtering and wet etching method. The sensor size is 6000 μm by 6000 μm. The sensor output voltage was measured for various applied pressure levels from -0.9to 1.2 bar with 5V voltage supply. The fabricated pressure sensor also exhibits a sensitivity of 50.1 mV/bar

Giant magnetoresistance (GMR) spin-valve based magnetic sensor with linear and bipolar characteristics for low current detection

High sensitivity linear, bipolar, and hysteresis-free magnetic field sensor is necessary for low current measurement of the order of 1000 mA with a resolution of 1 mA. Magnetoresistive technology has evolved into popular magnetic sensing technology where magnetic multilayered structures were tailored to obtain linear output characteristics. In this report, a GMR spin-valve structure was used to develop magnetic field sensing elements. Mechanical assembly of the sensing elements in the form of a Wheatstone bridge configuration was made to have the linear and bipolar characteristics of the sensor. Application of the constant DC biasing field perpendicular to the sensitivity axis was made to have fully hysteresis-free output characteristics and the maximum sensitivity was achieved of the order 2 to 2.5 mV/G with a supply of 1 mA current to the bridge circuit. The in-house developed spin valve sensor was then used to measure the current in the range of ± 1 A, having a sensitivity of the order of 2 mV/mA with a resolution down to 1 mA by using non-intrusive current sensing technology. A core-based sensor has a large aperture size that accommodates a current-carrying conductor with an ampacity of 1 kA. The calibrated output shows the sensor can measure the field in the range of ± 0.4 mT with a resolution of ∼ 200 nT and has the potential for floating current measurement application in the battery management system.

Computational modeling of nickel–titanium orthopedic staples in the treatment of a fractured scaphoid: Effects of staple bridge configuration

Internal fixation devices made of nickel-titanium (NiTi) staples have the advantage of producing compressive stress at the fracture site due to their unique shape memory effect and superelasticity. In the present study, a comparison was made between two commercial NiTi staples of the same size but with different bridge configurations, used for scaphoid fracture fixation. The staple and scaphoid anatomical configurations were modeled using SolidWorks, while ABAQUS software was used to analyze the stress and displacement caused by staples and distributed in the scaphoid waist. In the staple with a straight bridge, the regions under the tips of the staple legs underwent the largest stress, whereas there was negligible stress in the regions closer to the staple bridge. In the staple with an S-shaped bridge, the stress concentration was highly localized in the region close to the staple bridge, with a maximum stress that was over eight times higher than in the staple with a straight bridge. Considering the amount and distribution of stress in both staples, neither of the staples was able to create the ideal healing condition on the fracture surface.

ANALISIS PERFORMANCE INVERTER FULL BRIDGE SATU FASA

Technological advances are increasingly rapid and cannot be separated from the use of electricity for various types of electronic devices that use electrical energy. The use of electrical energy cannot be separated from DC and AC energy sources. The electric voltage itself can be done by changing or converting electrical energy from DC to AC using an inverter. The inverter itself is a device that can convert DC voltage to AC with a full bridge configuration that uses a transformer to get the best efficiency using a transformer, using an input voltage of 12 VDC to get 220 VAC by changing the value of the duty cycle used to find the results of the PWM wave and get the efficiency value. From these experiments it was then tested with 15W and 30W loads to get good efficiency values and wave output results.

A 15-Tiered Multi-Level Inverter Designed for Use in PV and HEV Applications

The basis of this project centers around different topologies and the cascaded H bridge inverter. The primary application of inverters is for businesses and manufacturing needs. The multilevel inverter's distinct arrangement results in decreased output voltage harmonics. Multilevel inverters come in various variations. Cascaded multilevel inverters have acquired a lot of attention in the power industry due to their demand for fewer components. When the level count rises, the harmonic components in the voltage waveform output decline. The inverter with fifteen levels constructed in a cascaded H- bridge configuration utilizes the fewest possible switches. The waveform generated through synthesis becomes more like the desirable waveform as the level rises due to the increasing number of steps producing a staircase wave. By using a small number of switches, the issue of switch losses and power losses can be completely resolved.

Aerodynamic Characterization of the 516 Arouca Pedestrian Suspension Bridge over the Paiva River

Given the 516 Arouca pedestrian suspension bridge’s design and characteristics, the owner, a municipality, required a set of tests in order to evaluate its aerodynamic characteristics and dynamic response, aiming at both structural safety and user comfort. Wind tunnel tests were performed over a sectional scaled model to obtain the static aerodynamic coefficients and dynamic response. The tests were carried out on different bridge configurations—a deck with people and a deck with an arch for secondary cables (connecting each suspension point to the catenary on the opposite side of the deck)—for the static coefficients. For the dynamic response, only the deck alone was tested. A major challenge had to be overcome, as the main displacement mode belonged to a swing movement, to assemble a wind tunnel setting, requiring a suspension system allowing wind displacements. A persistent trend of small amplitude displacements was identified, influencing user comfort and contributing to the installation of the secondary cables, but no aerodynamic instabilities were identified.

Cyclopropane as an Unsaturation "Effect Isostere": Lowering the Melting Points in Lipid-like Ionic Liquids.

The replacement of unsaturation with a cyclopropane motif as a (bio)isostere is a widespread strategy in bacteria to tune the fluidity of lipid bilayers and protect membranes when exposed to adverse environmental conditions, e.g., high temperature, low pH, etc. Inspired by this phenomenon, we herein address the relative effect of the cyclopropanation, both cis and trans configurations, on melting points, packing efficiency, and order of a series of lipid-like ionic liquids via a combination of thermophysical analysis, X-ray crystallography, and computational modeling. The data indicate there is considerable structural latitude possible when designing highly lipophilic ionic liquids that exhibit low melting points. While cyclopropanation of the lipid-like ionic liquids provides more resistance to aerobic degradation than their olefin analogs, the impact on the melting point decrease is not as pronounced. Our results demonstrate that incorporating one or more cyclopropyl moieties in long aliphatic chains of imidazolium-based ionic liquids is highly effective in lowering the melting points of such materials relative to their counterparts bearing linear, saturated, or thioether side chains. It is shown that the cyclopropane moiety effectively disrupts packing, favoring formation of gauche conformer in the side chains, resulting in enhancement of fluidity. This was irrespective of the configuration of the methylene bridge, although marked differences in the effect of cis- and trans-monocyclopropanated ILs on the melting points were observed.

INTEGRAL BRIDGE WITH RS‐OVERPASS TECHNOLOGY – STEP INTO THE FUTURE OF STANDARD HIGHWAY OVERPASSES

AbstractStarting from Germany, the VFT bridge girder technology (prefabricated composite beam) has spread in several European countries in the last decades as further development of the standard steel‐concrete composite solution. Its configuration fits perfectly to integral frame bridges built over existing infrastructure with the scope to minimize the traffic disturbance. In this paper a further development with the focus on cost efficiency in span ranges of 40‐55 m is proposed: the RS‐Overpass technology. The change consists in using standard rolled sections by adapting them into the integral frame bridge configuration, further enhancing the structural efficiency with the benefits of high‐steel strength. The constructive details to achieve the polygonal form have been studied to allow easy fabrication and a maximal clearance height over highway traffic lanes. The RS‐Overpass solution is conceived as the economic option of standard highway overpasses, with the aim of a overall construction cost reduction of 5%. The possibility of weathering steel or hot‐dip galvanization create the unique offer for a maintenance‐free solution.

Highly Sensitive Readout Interface for Real-Time Differential Precision Measurements with Impedance Biosensors.

Field deployment is critical to developing numerous sensitive impedance transducers. Precise, cost-effective, and real-time readout units are being sought to interface these sensitive impedance transducers for various clinical or environmental applications. This paper presents a general readout method with a detailed design procedure for interfacing impedance transducers that generate small fractional changes in the impedance characteristics after detection. The emphasis of the design is obtaining a target response resolution considering the accuracy in real-time. An entire readout unit with amplification/filtering and real-time data acquisition and processing using a single microcontroller is proposed. Most important design parameters, such as the signal-to-noise ratio (SNR), common-mode-to-differential conversion, digitization configuration/speed, and the data processing method are discussed here. The studied process can be used as a general guideline to design custom readout units to interface with various developed transducers in the laboratory and verify the performance for field deployment and commercialization. A single frequency readout unit with a target 8-bit resolution to interface differentially placed transducers (e.g., bridge configuration) is designed and implemented. A single MCU is programmed for real-time data acquisition and sine fitting. The 8-bit resolution is achieved even at low SNR levels of roughly 7 dB by setting the component values and fitting algorithm parameters with the given methods.

Integrating microbial fuel cell with sedum green roof for stormwater retention and renewable energy generation

Climate change brings frequent and intense storms, which challenge aging stormwater infrastructures. As a sustainable stormwater solution, green roofs are being more frequently used in urban areas. However, high installation and maintenance costs have limited applications of green roofs on a large scale. A plant microbial fuel cell (P-MFC) is a novel technology that uses bacteria living around the root of plants to generate electricity. This study explores the integration of P-MFCs with an extensive green roof module for the dual benefit of stormwater runoff reduction and renewable energy generation. While most P-MFC systems in the literature are based on flooded plants, the green roof MFC developed in this study uses sedum plants which are among the most common vegetation layers for green roof solutions. We hypothesized that MFC efficiency could be improved by introducing a water storage layer and capillary sub-irrigation. Moreover, the capillary irrigation wick can function as a salt bridge to further enhance power generation. Three prototypes were fabricated to test our hypotheses, including a control unit without sub-irrigation and two units with capillary irrigation and one with additional salt bridge configuration. Experiments demonstrated that capillary irrigation and the salt bridge configuration significantly increased P-MFC’s power density and decreased the internal resistance. The research demonstrated that green roof modules with integrated P-MFCs can be a renewable energy generator, promoting the adoption of green roofs as sustainable solutions for climate resilience by simultaneously reducing storm floods, capturing carbon dioxide (CO2) in the atmosphere, and producing green electricity.

Arthroscopic Fixation of Posterior Cruciate Ligament Avulsion Fracture with Combined Suture Tape and Internal Bracing by Suture-bridge Technique

Background: Tibial-sided avulsion fracture of the posterior cruciate ligament (PCL) almost always require surgical intervention. Multiple techniques of reduction and fixation have been described in the literature from open/mini-open conventional screw fixation to the all-arthroscopic fixation techniques. Recent evidence shows that the all-arthroscopic fixation techniques had higher subjective and objective knee outcome scores with the advantage of addressing concomitant intra-articular injuries such as osteochondral injuries or meniscal problems. Objectives: We propose an arthroscopic fixation technique using suture tapes placed in a suture-bridge technique and combined it with internal bracing to fix tibial-sided avulsion fracture of the PCL. Surgical Technique: After routine diagnostic knee arthroscopy in supine position via standard anterolateral and anteromedial portal, two standard posteromedial and posterolateral portal was created. A standard PCL aiming guide was used to create the tibial tunnel. PCL was secured using two single-looped suture tapes around it with both limbs brought to the posterior compartment through either side of the PCL (medial and lateral). Internal bracing was done with suture tape secured to the femoral side using fixed suspensory device and brought to the posterior compartment through the lateral side of the PCL. All tapes are then passed through the tibial tunnel in a suture-bridge manner and fixed to a button in 30° flexion while reduction quality was constantly checked under direct visualization. Results: The suture bridge configuration provides direct bone-to-bone healing and secure enough fixation for early range of motion and power exercises. All-arthroscopic approach avoids posterior element related complications such as fragment comminution and neurovascular injuries. Conclusions: This technique can be considered as a safe and effective method for fixation of tibial-sided PCL avulsion fracture, which allows active mobilization with lowered risk of complications.

Resistive-Based Micro-Kelvin Temperature Resolution for Ultra-Stable Space Experiments.

High precision temperature measurements are a transversal need in a wide area of physical experiments. Space-borne gravitational wave detectors are a particularly challenging case, requiring both high precision and high stability in temperature measurement. In this contribution, we present a design able to reach 1 μK/Hz in most of the measuring band down to 1 mHz, and reaching 20 μK/Hz at 0.1 mHz. The scheme is based on resistive sensors in a Wheatstone bridge configuration which is AC modulated to minimize the 1/f noise. As a part of our study, we include the design of a test bench able to guarantee the high stability environment required for measurements. We show experimental results characterising both the test bench and the read-out, and discuss potential noise sources that may limit our measurement.

Justification of the parameters of regulationof forces for steel-reinforced concrete span structures from project “43282 km” by TSNIIPSK

Steel-reinforced concrete spans in road bridges have been widely used since the late 1950s, in the configuration of large-span bridges built across significant water barriers. To date, the issue of the need to reconstruct such span structures, including those designed and built according to the project “43282 km” developed by TsNIIPSK, is becoming increasingly relevant. The authors analyze the stages of the production of works of a particular object, developed for the implementation of the entire complex of works on its reconstruction using the method of force regulation. The presented order of work was successfully implemented during construction of the bridge over Kabarga River in Primorsky Krai. This made it possible to preserve the existing structure of the span (main beams and braces), replacing the worn-out reinforced concrete slab with a new - metal orthotropic one, while ensuring that the conditions of strength and stability of the flexural-torsional shape of solid-walled beams are met, in the process of dismantling the existing roadway slab and constructing a new one. Considering that steel-reinforced concrete bridges are built across large water barriers and have a very significant cost due to their large length, reconstruction using existing supports can significantly reduce the cost of construction, so, the possibility of upgrading the existing steel-reinforced concrete span structure is, undoubtedly, relevant. Based on the structural and technological measures presented by the authors, it is possible to carry out and effectively implement work on the reconstruction of the existing steel-reinforced concrete bridges that do not fully meet modern requirements for load capacity and throughput.

Internal resonance of generalized suspension bridge model considering torsional-vertical vibration

Non-linear vibration is a crucial issue for suspension bridge due to its slenderness and low damping. This study proposes a fully mathematical model of a suspension bridge considering arbitrary inclined angle of main cables by using principle of Hamilton. This is the first mathematical model that is capable of analyzing the nonlinear coupled vertical-torsional vibration of generalized bridge configurations with independently considering the motion of main cables and girder. Galerkin method is adopted for the discretization of the model, and the multi-scale method is employed to acquire modulation equations. The accuracy of the non-linear vibration obtained from proposed mathematical model are validated by a FE model. The internal resonance analysis for such a suspension bridge with spatial layout of main cables between vertical and torsional modes with frequency ratio of 2:1, and between two torsional modes respectively dominated by deck and main cables with frequency ratio of 1:1 are successively investigated in the first time within a narrow detuning frequency domain. The phenomenon of nonlinear resonance was discussed with different inclination angle of main cables and detuning parameters. Some novel and practical conclusions were obtained. Results show that 2:1 internal resonance between vertical and torsional modes may be induced only when two forces with frequencies corresponding to involved modes are applied simultaneously. In addition, significant 1:1 internal resonance is observed, with inducing Hopf bifurcation. Understanding such possible situations is favorable to the design of bridge structure.

Development of a Flexible Integrated Self-Calibrating MEMS Pressure Sensor Using a Liquid-to-Vapor Phase Change.

Self-calibration capabilities for flexible pressure sensors are greatly needed for fluid dynamic analysis, structure health monitoring and wearable sensing applications to compensate, in situ and in real time, for sensor drifts, nonlinearity effects, and hysteresis. Currently, very few self-calibrating pressure sensors can be found in the literature, let alone in flexible formats. This paper presents a flexible self-calibrating pressure sensor fabricated from a silicon-on-insulator wafer and bonded on a polyimide substrate. The sensor chip is made of four piezoresistors arranged in a Wheatstone bridge configuration on a pressure-sensitive membrane, integrated with a gold thin film-based reference cavity heater, and two thermistors. With a liquid-to-vapor thermopneumatic actuation system, the sensor can create precise in-cavity pressure for self-calibration. Compared with the previous work related to the single-phase air-only counterpart, testing of this two-phase sensor demonstrated that adding the water liquid-to-vapor phase change can improve the effective range of self-calibration from 3 psi to 9.5 psi without increasing the power consumption of the cavity micro-heater. The calibration time can be further improved to a few seconds with a pulsed heating power.

Influence of interfacial configuration on bonding properties and thermal conductivity of heterogeneous interface in Al/Graphite composite used for electronic packaging

With the purpose of improving the service performance of aluminum(Al)/graphite(Gr) composites used for electronic packaging, the density functional theory (DFT) calculations were employed to investigate the influence of the interfacial configuration on the bonding properties and thermal conductivity of Al/Gr heterogeneous interface. The Al(111)/Gr(0001) interfaces with the low mismatch (0.569%) were first constructed by lattice transformation, and two different interfacial configurations of Top and Bridge were determined. The calculated results indicate that, the interfacial bonding properties of Al(111)/Gr(0001) interfaces are determined by interfacial Al–C bonding behavior. Although the covalent characteristics of Al–C bonds are similar for the two configurations, the ionic characteristics for Top configuration are significantly stronger than Bridge configuration. Therefore, the Top configuration has not only a greater bonding strength than Bridge configuration manifested as the larger interfacial work of adhesion for 0.323 J/m2 and ideal tensile strength of 1.47Gpa, but also the better plasticity with the sustainable maximum strain of 10.46%. Moreover, the thermal conductivity of Top configuration is higher than that of Bridge configuration and the maximum values of the two configurations are 4.90 and 3.75×10−2·W·m−1·k−1, respectively. The mechanism for the favorable thermal transport properties of Top configuration compared to Bridge configuration lies in the high electron density and the large degree of electron delocalization at the interface. Therefore, the Top configuration is the promising Al(111)/Gr(0001) interfacial configuration, which can significantly improve the bonding properties and thermal conductivity of the Al/Gr composite.

CO2 Thermal Conductivity Detection in Gas Mixture for Concentration Measurement Using Bridge Configuration of Thermopiles

In this research, improvisation was carried out by modifying the market IR thermopile which functions as a thermal conductivity detector to measure the concentration of CO2 gas in the gas mixture. Four thermopiles are configured with a Wheatstone bridge with the aim of increasing the accuracy of the measurement system in detecting changes in CO2 concentration in the gas mixture (N2 and CO2). Using the bridge configuration of these four thermopiles, this measurement system can measure changes in CO2 concentration in small orders. The sensor developed is easy to manufacture, low cost, and has high linearity as evidenced by a correlation coefficient of 0.9943. From the experiments carried out, the sensor works quite accurately in detecting CO2 concentrations with the sensor’s sensitivity of -88.19 Volt/%, the detection range is 0% to 100%, and the RMS error value is 2.25.