Multi Configuration Research Articles

Comparative study of various types of laser active media for solar pumping in multi-rod configurations

The Nd:YAG, Ce:Nd:YAG, and Cr:Nd:YAG active media in multi rod configuration are investigated for solar-pumped lasers using simulation methods. A statistical model employing Monte Carlo photon tracing simulates a laser system with multiple rods for combined end-side solar radiation pumping. The model enables one to evaluate efficiency, pump distribution, and output parameters of solar lasers. Simulation analyses is conducted on a three-rod setup using the aforementioned active media. Comparative results demonstrate that Cr:Nd:YAG achieves the highest efficiency, reaching an overall conversion efficiency of 5% at 500 W pump power, which is twice that of Nd:YAG lasers under similar conditions.

Comparative assessment of a multitudinal piezo arrangement for non-destructive evaluation of construction steel: An experimental study

Recently, sensor-based health diagnostic methods have attracted remarkable attention and can be replaced with conventional nondestructive techniques due to their robustness, reliability, and ease of implementation. Multisensing, reusable, and non-bonded configurations of PZT patches for impedance-based health monitoring are gaining popularity because of their simplicity and robustness. However, the steel bar's complex or uneven surface restricts the PZT patch's direct bonding to the host structure. This article evaluates the effectiveness of different multisensing configuration of PZT patch to monitor the loading effect and structural damage in constructional steel rebar, i.e., surface bonded, clamped and metal wire (MW) attached. Statistical and piezo frequency-based damage indices were used to assess the PZT's effective configuration. The experimental findings of this study have shown the efficacy of multi modal piezo configuration for monitoring damage and loading effects, particularly. Furthermore, the study has expanded to find piezo-equivalent structural parameters for multitudinal piezo position to identify its suitability and effectiveness for better structural health assessment and monitoring. The comparison of indices was highlighted to find a more productive PZT configuration for sensing structural change and damage highlighting the effectiveness of the non-bonded PZT patch configuration. The overall results demonstrate good agreement of employing multisensing array for monitoring damage and progressive loading, specifically the non-bonded configuration of the PZT patch.

Study of jet tabs in 2D convergent–divergent nozzle for thrust vectoring in aerial vehicles

PurposeIn this study, 2D density-based SST K-turbulence model with compressibility effect is used to observe the flow separation and shock wave interactions of the flow. The wall static pressure and Mach number differences are also evaluated. This study aims to discuss the aforementioned objectivesDesign/methodology/approachThis study outlines the evaluation of the performance of a 2D convergent–divergent nozzle with various triangular jet tab configurations that can be used for effective thrust vectoring of aerial vehicles.FindingsFrom the study, it is seen that the shadow effect induced by the tab with a height of 30% produces higher oblique wave deflection and higher thrust deflection at the exit nozzle. The numerical calculation concluded that thrust vector efficiency of 30% jet tab is, 0.46%. In the case of 10% jet tab height the thrust vector efficiency is higher, i.e. 1.647%.Research limitations/implications2D study.Practical implicationsThe optimization will open up a new focus in TVC that can be implemented for effective attitude control in aircrafts.Social implicationsUsed in future aircrafts.Originality/valueThe influence of shadowing ratio with different tab heights at different Mach numbers has not been reported in the previous studies. Few of the studies on jet tab are focused on the acoustic studies and not pertaining to the aerodynamic aspects. The multi jet configuration, the combination of location, shapes and other parametric analysis have not been covered in the previous studied.

Comparison of two cable configurations in 3D printed steerable instruments for minimally invasive surgery.

In laparoscopy, a small incision size improves the surgical outcome but increases at the same time the rigidity of the instrument, with consequent impairment of the surgeon's maneuverability. Such reduction introduces new challenges, such as the loss of wrist articulation or the impossibility of overcoming obstacles. A possible approach is using multi-steerable cable-driven instruments fully mechanical actuated, which allow great maneuverability while keeping the wound small. In this work, we compared the usability of the two most promising cable configurations in 3D printed multi-steerable instruments: a parallel configuration with all cables running straight from the steerable shaft to the handle; and a multi configuration with straight cables in combination with helical cables. Twelve participants were divided into two groups and asked to orient the instrument shaft and randomly hit six targets following the instructions in a laparoscopic simulator. Each participant carried out four trials (two trials for each instrument) with 12 runs per trial. The average task performance time showed a significant decrease over the first trial for both configurations. The decrease was 48% for the parallel and 41% for the multi configuration. Improvement of task performance times reached a plateau in the second trial with both instruments. The participants filled out a TLX questionnaire after each trial. The questionnaire showed a lower burden score for the parallel compared to multi configuration (23% VS 30%). Even though the task performance time for both configurations was comparable, a final questionnaire showed that 10 out of 12 participants preferred the parallel configuration due to a more intuitive hand movement and the possibility of individually orienting the distal end of the steerable shaft.

Comparative analysis of behaviour of horizontal and vertical irregular buildings with and without using shear walls by ETABS software

At present days building a structure with all the regular configurations is not feasible in most of the cases due to the irregular plot dimensions, aesthetic visual and functional requirements in the urban cities. The structure with more irregular configuration either horizontally or vertically are more vulnerable to earthquake & wind forces which leads to collapses of structure, property loss and casualties. Although a considerable amount of research effort was made on capturing the responses of irregular configuration structures under the earthquake forces, but well-accepted guidelines for multi storey irregular configuration structures are still yet to be framed. In this aspect a question might arise in the mind of structural engineers designing a high-rise structure i.e., which irregular configuration of structures and type of structures provide considerably good responses to the earthquake forces in reducing the damage caused by earthquakes and cost effective in implementing. A well-known answer is that shear walls provide good response to resist lateral forces when added to a structure.In the present study a structure with horizontal irregularity, vertical irregularity, Stiffness irregularity and Mass irregularity buildings with and without shear wall is considered and responses of the buildings are compared. Modeling of these 4 types of models with and without shear walls are done with ETABS software for G + 15 storey. The goal of the study is to compare model results like Stiffness, Displacement, Shear & Drift values and find out which model performs better. Vertical geometrical irregular building with shear wall has shown considerably better performance than other irregular buildings.

Finite element method simulating bursting process of multi-chamber flexible package infusion bag

This study aims to overcome the shortcomings such as low efficiency, high cost and difficult to carry out multi-parameter research, which limited the optimization of infusion bag configuration and manufacture technique by experiment method. We put forward a fluid cavity based finite element method, and it could be used to simulate the stress distribution and deformation process of infusion bag under external load. In this paper, numerical models of infusion bag with different sizes was built, and the fluid-solid coupling deformation process was calculated using the fluid cavity method in software ABAQUS subject to the same boundary conditions with the burst test. The peeling strength which was obtained from the peeling adhesion test was used as failure criterion. The calculated resultant force which makes the computed peeling stress reach the peeling strength was compared with experiment data, and the stress distribution was analyzed compared with the rupture process of burst test. The results showed that considering the errors caused by the difference of weak welding and eccentric load, the flow cavity based finite element method can accurately model the stress distribution and deformation process of infusion bag. It could be useful for the optimization of multi chamber infusion bag configuration and manufacture technique, leading to cost reduction and study efficiency improvement.

Exploring the x-ray photoabsorption spectrum of sodium in the energy range 1070–1090 eV by elucidating the inner shell excitation transition probabilities

The researchers report on a new study of the x-ray photoabsorption spectrum of sodium near the K-edge, involving the calculations of the excitation energies and the excitation transition probabilities for K-shell and M-shell electron excitations transitions in atomic sodium. The calculations were carried out by employing the ‘multi configuration Dirac–Fock method’, Breit interactions and ‘finite nuclear size corrections’ are included in the calculations, the transition probabilities were convoluted into ‘Breit–Wigner’ line shapes, and single 1s photoionization was also taken into account. In addition, the [1s]np and the [1s3s]ns n′p singlet–triplet energy splitting was calculated. Results of the calculations were compared with previous measurements of the photoabsorption spectrum of sodium near the K-edge, and a very good agreement was observed.

Aerodynamic Investigation of Morphing Wing UAV with Adjustable Slotted Airfoil Configuration

Aviation has wide aspects to challenge and discover, the ability to land and take off at slow speed, sudden increase in drag for short runway landings. This paper puts forth the solution by the use of adjustable multi slots configuration of an airfoil. In this case, the slots extend from the wing leading edge to trailing edge. This causes change in the chord, thereby changing the camber of unsymmetrical airfoil. An investigation was made to determine and compare the aerodynamic characteristics of multi slotted adjustable airfoil with unmorphed unsymmetrical airfoil at varied speeds and Angle of Attack (AoA). There are three slots distanced equally along the airfoil. The extension of these slots increases the chord length by 10% of total chord. The slotted and unslotted airfoil profile are then studied using computational fluid dynamics of external flow over a body. The flow simulation is done at 10m/s, 20m/s, 30m/s, 40m/s and 50 m/s flow velocity and at 0, 3, 6, 9 ,12, 15 AoA. The results were obtained for each case and the values for base and slotted model were compared. It was found that lift of slotted model is slightly higher than base model at low flow velocity. It was also seen that the use of slots at high speed causes a large amount of drag. This increased drag factor can be used in UAV’s as spoilers during landing or for landing at shorter runways at lower speed, allowing a sudden decrease in aircraft speed and also to glide at a steeper angle over obstruction.

Optimization of wing structure using carbon fibre on a combined shell blended wing body

Composite materials have many advantages in macro materials and nanomaterials. The strength of composite material is fully based on the orientation of ply. This research deals with the pressurized inner wing. Such design of the wing and fuselage remains a significant challenge for Flying Wing aircraft. Since the inner wing is nearly rectangular, it is relatively inefficient to resist the pressure loads by bending that consequently brings weight penalty. The wing structure was evaluated by using carbon fibre material at different orientations on fabric. To reduce this weight penalty of the wing, the internal multi-shell structure was combined to form a boxed multi bubble section configuration. The novel section was modelled and the structural properties were evaluated.

Evaluation of tensile properties of hybrid kevlar-glass reinforced epoxy composite for multi holes configuration

Abstract Most modern structures are comprised of synthetic composites with more number of cut outs. For the design of synthetic composite with varying shapes with different sized cut-outs are often used in engineering structures. The effects of stress concentration factor and tensile behaviour has to be thoroughly investigated for providing better design aids to be utilized by design engineers. The present paper focuses on the tensile behaviour of the Kevlar and glass fiber reinforced hybrid polymer composite by varying size and position of the cut outs. The test specimens are prepared according to the ASTM standard D3039. The composite laminates are prepared by traditional hand layup method. The overall dimension of plates were 25 mm*250 mm (width*length) and with the gauge length was 110 mm. These plates were drilled with the circular holes of 8 mm and 5 mm. The larger hole of diameter 8 mm was drilled at centre of all the specimens and smaller holes of diameter 5 mm was drilled on either sides of 8 mm hole. The pitch for smaller 5 mm holes were increased in the order of 0, 15, 20, 25 and 30 mm respectively. The specimen with smaller holes at 25 mm pitch showed highest allowable stress of 97.22 MPa. The experimental results were compared to find the optimum position for placing the holes. This research also intends to find out if there exists any relationship between the pitch, diameter of smaller and larger holes present in the specimen.

Assessing the performance of vehicles powered by battery, fuel cell and ultra-capacitor: Application to light-duty vehicles and buses

As alternative vehicle technologies gain more importance in the market, this work assesses the possibility of a multi power source vehicle configuration by evaluating the performance of an electric vehicle powered by battery (BEV), fuel cell (FCEV), ultra-capacitor (UC) and combination of the former. A flexible vehicle simulation model was developed in MATLAB-Simulink and vehicle performance was evaluated in various 1 Hz certified cycles, enabling the assessment of light duty and heavy-duty vehicles powered by various power sources. The developed model accurately estimates energy consumption and range of passenger vehicle with an average absolute error of less than 4% and 2% for the electric bus. The study showed that BEV has the least energy consumption (23%), followed by FCEV (65%) compared to internal combustion engine (ICE) vehicles in real world conditions. Regarding the combination of energy sources, an increase in range by 10% is estimated when battery is combined with fuel cell, while combining ultra-capacitor with battery enables a lifetime extension of battery life by 10%, with negligible change in range. Combining secondary sources with fuel cell shows a reduction of total fuel cell capacity by 40% for the same operation. Analysis on ultra-capacitor showed negative response with light duty vehicle, while for buses the usage of batteries shows positive results with negative impacts on cost and recharging time. Ultra-capacitors are highly recommended for short-frequent trips with fast recharging and a life of 20 years, while fuel cells as a primary energy source are recommended for the long-range trips in coaches and trucks.

Theoretical investigation of the H + HD → D + H2 chemical reaction for astrophysical applications: A state-to-state quasi-classical study.

We report a large set of state-to-state rate constants for the H + HD reactive collision, using Quasi-Classical Trajectory (QCT) simulations on the accurate H3 global potential energy surface of Mielke et al. [J. Chem. Phys. 116, 4142 (2002)]. High relative collision energies (up to ≈56 000 K) and high rovibrational levels of HD (up to ≈50 000 K), relevant to various non thermal equilibrium astrophysical media, are considered. We have validated the accuracy of our QCT calculations with a new efficient adaptation of the Multi Configuration Time Dependent Hartree (MCTDH) method to compute the reaction probability of a specific reactive channel. Our study has revealed that the high temperature regime favors the production of H2 in its highly rovibrationnally excited states, which can de-excite radiatively (cooling the gas) or collisionally (heating the gas). Those new state-to-state QCT reaction rate constants represent a significant improvement in our understanding of the possible mechanisms leading to the destruction of HD by its collision with a H atom.

UNJUK KERJA COOL BOX BERBASIS THERMOELEKTRIK COOLER DENGAN SINGLE DAN MULTI-STAGE TERMOELEKTRIK

Thermoelectric technology works by converting thermal energy into electricity directly or preferably. Thermoelectric technology works by converting thermal energy into electricity directly or preferably. Theuse of thermoelectric as a cooler in cool box systems has been extensively studied. The thermoelectric cool ability can be achieved depending on the design of a good system. Therefore, this study aims to determine the performance of thermoelectric cooler cool box based on single and multi stage. Tests carried out using cool boxes of dimensions of 31 cm x 19 cm x 24 cm witha thickness of 3 cm and with the TEC1 12706 module. The voltage used in each configuration is 12 Volts. Temperature data readings on laptops using DAQNavi_SDK data logger connected to type K thermocouples. The result showed the multi stage configuration reached a room temperature of around 19.3 oC and 21.8 oC for single stage. Meanwhile, the multi stage configuration COP value is 1.36 and with a single stage configuration is0.88. It can be concluded that the thermoelectric configuration has an influence on the performance of the cool box system.
 Keywords: Cool box, Thermoelectric module, Multi stage, single stage, COP

Bandwidth characteristics of TWSOA based inline detector configurations for near infrared communications

Travelling Wave-Semiconductor Optical Amplifier (TWSOA) based 1.55 µm inline detectors are analyzed for their bandwidth characteristics under simultaneous amplification mode. Four different configurations of inline detector are considered for this study and they are full length, short length, multisection and optimum differential electrode based detector configurations. From the numerical solutions of rate equation, it is found that the short length configuration provides a bandwidth of 3 GHz and responsivity of 1650 V/W at − 20 dBm input power, compared to full length and multisection configurations. Optimum differential configuration has the best responsivity characteristics of 3600 V/W at 100 mA at − 20 dBm input power and provides two fold improvement in detection voltage than the best scheme reported earlier. However the bandwidth saturates for higher powers. For applications which demands greater responsivity with considerable bandwidth, the optimum differential configuration could be used. Applications those require higher dynamic bandwidth characteristics, the short length configuration and multi electrode configuration could be useful.

Ku Band Bethe Hole Coupler Using Gap Waveguide Technology

The gap waveguide technology is a new technique used for designing and fabricating microwave components, ensuring a low-loss and easy fabrication process, especially at high frequencies, and allowing for the production of multilayer structures due to the lack of requirement of an electrical connection between the metal layers of the waveguide structure. This paper presents the design and areas of implementation of single-hole and multi-hole 20 dB Bethe couplers, using the groove gap waveguide (GGW) technology for Ku band. Simulation results show that the operating bandwidth of the proposed design is over 40% wider, and its isolation rate is more than 25 dB higher. By using the multi hole configuration, a bandwidth that is more than 59% wider and the isolation rate of over 30 dB may be obtained.

Optimization approach to retrieve soil surface parameters from single-acquisition single-configuration SAR data

This study suggests a novel approach to the retrieval of soil surface parameters using a single-acquisition single-configuration synthetic-aperture radar (SAR) system. Soil surface parameters such as soil moisture and surface roughness are key elements for many environmental studies, including Earth surface water cycles, energy exchange, agriculture, and geology. Remote sensing techniques, especially SAR data, are commonly used to retrieve such soil surface parameters over large areas. Several backscattering models have been proposed for soil surface parameters retrieval from SAR data. However, commonly, these backscattering models require multi configuration SAR data, including multi-polarization, multi-frequency, and multi-incidence angle. Here we propose a methodology that employs single-acquisition single-configuration SAR data for the retrieval of soil surface parameters. The originality is to use single-acquisition single-configuration SAR data to retrieve the soil surface parameters using an optimization approach by the genetic algorithm (GA); we have used the modified Dubois model (MDM) in HH polarization as the backscattering model. Three HH polarization and C band data sets from Quebec (Radarsat-1), Ontario (SIR-C), and Oklahoma (AIRSAR) were analyzed. The retrieved values of soil moisture and soil surface roughness were then compared to ground truth measurements with corresponding parameters. We employed diverse criteria, including the mean absolute error (MAE), the root mean square error (RMSE), the coefficient of performance (CP), and the correlation coefficient to investigate the performance of the proposed methodology. This analysis suggests the capability of the GA for the retrieval of soil surface parameters. Based on our findings, this method presents a viable alternative approach to the retrieval of soil surface parameters when only single-acquisition single-configuration SAR data is available.

Multi-configuration Stiffened Panels under Compressive Load: Part 1 – Theoretical Analysis

Stiffened panels are the structure used in the aircraft wing skin panels. Stiffened panels are often critical in compression load due to its thin structural configuration. This paper analyzes the critical loads of a multi configuration stiffened panels under axial compressive loading. The study comprised three main sections; theoretical analysis, numerical analysis and experimental analysis. The present paper deals only with the theoretical analysis. This first part of analysis is very important since the results will be the main input parameter for the subsequent numerical and experimental analysis. The analysis was done on the buckling properties of the panels. Four panel configurations were investigated. Results showed that even though the stiffened panels have the same cross-sectional area, their critical loads were not identical.

Synthetic jet Reynolds number based on reaction force measurement

The paper presents a new method for calculating Reynolds number and dimensionless stroke length based on synthetic jet actuator reaction force measurement. The new method was validated for axisymmetric synthetic jet and classical Reynolds number from about 2000 to 25000 and dimensionless stroke length from 0.5 to about 100, obtaining the coefficient of determination R2=0.90 for Reynolds number and R2=0.94 for dimensionless stroke length. New method is simple, time and cost effective, allows measuring the Reynolds number for orifices of any shape and multi orifices configuration.

Design and development of a novel triphibian quadcopter

Multimodal Vehicles can travel in at least two distinctive modes of transportation, be it air and water, land and water or air and land. In this paper, design and development of a novel unmanned multimodal vehicle is presented that can travel in air, land and water, also called a as a triphibian quadcopter which would prove beneficial in rescue operations and operations involving hazardous environments. The vehicle is essentially a mix of unmanned aerial vehicle, unmanned ground vehicle and unmanned surface vehicle and is equipped with mechanisms to travel in land, air and water at the will of the operator. The entire framework of the vehicle is built on the multi rotor configuration. Flight tests were conducted to validate the design.

CO quantum dynamics diffusion on Cu(1 0 0)

We present a quantum mechanical study of the diffusion of CO molecules on the Cu(001) surface. We use the Strasbourg-Amsterdam-Postdam potential surface and a “non-tunnel”-variant hereof; to mimic an initial state that is localized in one adsorption well, a “local-potential-shift” concept is introduced; the Multi Configuration Time Dependent Hartree method to perform the calculations. Special emphasis is placed on the effect of the dimensionality of the models. Surprisingly, tunneling plays an important role typically 1 ps after the beginning of the dynamics; it dominates at around 1 ns and might, at least partly, explain the long diffusion rates measured experimentally for the system.