Tip End Research Articles

In silico interactions and deep neural network modeling for toxicity profile of methyl methanesulfonate.

In this study, the toxicity induced by the alkylating agent methyl methanesulfonate (MMS) in Allium cepa L. was investigated. For this aim, bulbs were divided into 4 groups as control and application (100, 500 and 4000µM MMS) and germinated for 72h at 22-24°C. At the end of the germination period root tips were collected and made ready for analysis by applying traditional preparation methods. Germination, root elongation, weight, mitotic index (MI) values, micronucleus (MN) and chromosomal abnormality (CAs) numbers, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities and anatomical structures of bulbs were used as indicators to determine toxicity. Moreover the extent of DNA fragmentation induced by MMS was determined by comet assay. To confirm the DNA fragmentation induced by MMS, the DNA-MMS interaction was examined with molecular docking. Correlation and principal component analyses (PCA) were performed to examine the relationship between all parameters and understand the underlying structure and relationships among these parameters. In the present study, a deep neural network (DNN) with two hidden layers implemented in Matlab has been developed for the comparison of the estimated data with the real data. The effect of MDA levels, SOD and CAT activities at 4 different endpoints resulting from administration of various concentrations of MMS, including MN, MI, CAs and DNA damage, was attempted to be estimated by DNN model. It is assumed that the predicted results are in close agreement with the actual data. The effectiveness of the model was evaluated using 4 different metrics, MAE, MAPE, RMSE and R2, which together show that the model performs commendably. As a result, the highest germination, root elongation, weight gain and MI were measured in the control group. MMS application caused a decrease in all physiological parameters and an increase in cytogenetic (except MI) and biochemical parameters. MMS application caused an increase in antioxidant enzyme levels (SOD and CAT) up to a concentration of 500µM and a decrease at 4000µM. MMS application induced different types of CAs and anatomical damages in root meristem cells. The results of the comet assay showed that the severity of DNA fragmentation increased with increasing MMS concentration. Molecular docking analysis showed a strong DNA-MMS interaction. The results of correlation and PCA revealed significant positive and negative interactions between the studied parameters and confirmed the interactions of these parameters with MMS. It has been shown that the DNN model developed in this study is a valuable resource for predicting genotoxicity due to oxidative stress and lipid peroxidation. In addition, this model has the potential to help evaluate the genotoxicity status of various chemical compounds. At the end of the study, it was concluded that MMS strongly supports a versatile toxicity in plant cells and the selected parameters are suitable indicators for determining this toxicity.

Effects of step hole geometry and spray-wall interactions on spray atomization in LPDI injector

The study aims to analyze the spray atomization of liquefied petroleum gas direct injection (LPDI) injector based on the macroscopic and microscopic experiments. Two experimental injectors were used in the presence and absence of step hole, and the experimental fuels used n-heptane and n-butane.The macroscopic and microscopic spray characteristics as function of the application of step hole were analyzed using two experimental injectors and n-heptane fuel. The macroscopic spray experiments analyzed the initial spray, after the end of injection and nozzle tip wetting using near-field visualization, and microscopic spray experiment analyzed fuel–air atomization phenomenon as function of the application of step hole using PDPA equipment.In addition, macroscopic and microscopic spray characteristics were analyzed for two experimental fuels and spray-wall impingement using the presence of step hole injector. The macroscopic spray experiment analyzed the spray evaporation characteristics for the two experimental fuels and spray-wall impingement using the schlieren visualization, and microscopic spray experiment analyzed the fuel–air atomization phenomenon as function of the two experimental fuels and spray-wall impingement using PDPA equipment.It was found that the presence of step hole injector showed better atomization results than those of the absence of step hole injector. But, the tip wetting of the presence of step hole injector was poor than that of the absence of step hole injector. Furthermore, based on the schlieren experiment, a comparison of free and flat sprays with the two fuels found that the spray width and area of n-heptane in free spray exceeded those of n-butane owing to the vapor pressure of n-butane. However, in the flat spray, the spray width and area of n-butane were exceeded those of n-heptane. It was found that the atomization was promoted after the spray-wall impingement.

Comprehensive Beam Modeling, Secondary Dose Computations and Treatment Planning for a 1.5 T MRgRT System

Magnetic resonance imaging guided radiotherapy (MRgRT) combines soft tissue visualization with online adaptive radiotherapy. The MRgRT workflow is characterized by many steps which needs to be performed swiftly and therefore greatly benefits from automation. The purpose of this study was to model a MRgRT system for dose computation and intensity modulated radiotherapy (IMRT) planning within a 1.5 T magnetic field in an independent treatment planning system (iTPS) with automation functionalities. A beam model for a 1.5 T MRgRT system was commissioned in an iTPS using beam profiles and output factor measurements. The cryostat of the MRgRT system was modeled using a cylindrical multi-layer combination of epoxy and aluminum and matched to source-to-surface dependent cryostat scatter measurement in air, and corrected for angular dependent cryostat transmission readings. The beam model was used with a fast Monte Carlo dose engine to account for the electron return and electron streaming effects within an external magnetic field. The multi-leaf collimator (MLC) was characterized with a novel synchronous and asynchronous sweeping gap (aSG) test. The aSGs have a shift (between 0 - 40 mm) between adjacent leaves which remains constant over the sweep. Measured doses map the shadowing due to the tongue-and-groove (TG) exposure and TG and leaf tip (LT) parameters are derived to match this within the iTPS. Clinical IMRT plans of 10 prostate, 5 lymph node and 5 rectal plans created in the default clinical TPS were recomputed in the iTPS and evaluated with the corresponding plan-specific quality assurance measurements. In addition, three IMRT plans were optimized within the iTPS, delivered with the MRgRT system and evaluated using PSQA using a 3%/3mm gamma criterium with a 10% threshold. Monte Carlo dose computation in the iTPS closely resembled the measured profiles in the presence of the 1.5 T magnetic field. The cryostat scatter simulations were <0.7% compared to the measurements and literature. The aSG/SGs test demonstrated that the TG width gradually increased up to 1 mm for a distance of 15 mm away from the leaf tip end. These effects were closely replicated in the iTPS with a difference of <1.5% for 95% of the aSGs. The difference between the clinical dose and the dose calculation in the iTPS was, on average, <0.5% within the volume receiving 50% of the maximum dose. The gamma pass rate was 100% for 98% of the PSQA results. The plans optimized within the iTPS were successfully delivered at the MRgRT system. We successfully modeled and commissioned a 1.5 T MRgRT system in an independent TPS. The beam model can be used for a second opinion dose computation in a magnetic field and for direct treatment planning. Next, the beam model will be incorporated in a semi-automated and adaptive workflow using the iTPS.

Total Focusing (TFM) for the Ultrasonic Testing (UT) of drawn arc stud welding

This article describes the results obtained applying ultrasonic testing (UT) with phased arrays (PAUT) using full matrix capture (FMC) and total focusing method (TFM) for the inspection of drawn arc stud welding. Weld studs are usually directly applied on the top of a metal slab using a dedicated welding gun. This procedure involves heating the end tip of the stud using a strong electric arc created by a positive electric current. This welding procedure shall comply to various normative requirements, but on the other side there is not a clear reference to any applicable non-destructive method (NDT) to control the quality of the weld seam. Shear connectors are normally used in concrete/steel composite structures to allow the combined action of the concrete slab and the steel profile thereby increasing both the stiffness and strength of the structure. Flaws in this connection would result in severe bending and cracking of the entire structure. This article proposes an advanced UT method to inspect the weld between shear connections and metal slab using FMC. Data acquired with FMC are processed by TFM algorithms improving image resolution, signal to noise performances and allowing 3D data imaging. The combined use of PAUT searching units and signal processing with high resolution measurement shows a great potential in industrial NDT applied to civil engineering, resulting in a more effective, reliable, and faster inspection methodology than many other methods, such as radiographic testing (RT).

Localization of reference points in electromagnetic tracking data and their application for treatment error detection in interstitial breast brachytherapy.

Electromagnetic tracking (EMT) is a promising technology that holds great potential to advance patient-specific pre-treatment verification in interstitial brachytherapy (iBT). It allows easy determination of the implant geometry without line-of-sight restrictions and without dose exposure to the patient. What it cannot provide, however, is a link to anatomical landmarks, such as the exit points of catheters or needles on the skin surface. These landmarks are required for the registration of EMT data with other imaging modalities and for the detection of treatment errors such as incorrect indexer lengths, and catheter or needle shifts. To develop an easily applicable method to detect reference points in the positional data of the trajectory of an EMT sensor, specifically the exit points of catheters in breast iBT, and to apply the approach to pre-treatment error detection. Small metal objects were attached to catheter fixation buttons that rest against the breast surface to intentionally induce a local, spatially limited perturbation of the magnetic field on which the working principle of EMT relies. This perturbation can be sensed by the EMT sensor as it passes by, allowing it to localize the metal object and thus the catheter exit point. For the proof-of-concept, different small metal objects (magnets, washers, and bushes) and EMT sensor drive speeds were used to find the optimal parameters. The approach was then applied to treatment error detection and validated in-vitro on a phantom. Lastly, the in-vivo feasibility of the approach was tested on a patient cohort of four patients to assess the impact on the clinical workflow. All investigated metal objects were able to measurably perturb the magnetic field, which resulted in missing sensor readings, that is two data gaps, one for the sensor moving towards the tip end and one when retracting from there. The size of the resulting data gaps varied depending on the choice of gap points used for calculation of the gap size; it was found that the start points of the gaps in both directions showed the smallest variability. The median size of data gaps was ⩽8mm for all tested materials and sensor drive speeds. The variability of the determined object position was ⩽0.5mm at a speed of 1.0cm/s and ⩽0.7mm at 2.5cm/s, with an increase up to 2.3mm at 5.0cm/s. The in-vitro validation of the error detection yielded a 100% detection rate for catheter shifts of ≥2.2mm. All simulated wrong indexer lengths were correctly identified. The in-vivo feasibility assessment showed that the metal objects did not interfere with the routine clinical workflow. The developed approach was able to successfully detect reference points in EMT data, which can be used for registration to other imaging modalities, but also for treatment error detection. It can thus advance the automation of patient-specific, pre-treatment quality assurance in iBT.

Constructive layout for small rotor of straight-flow rotary ripper

Introduction. The problem of accelerating and cheapening the construction of roads without reducing their quality can be solved by creating a complex of continuous units. Units, following each other, carry out the whole complex of works aimed at roads construction. One of the elements of the continuous unit that forms the ditch is a straight-flow rotary ripper. It was found that in order to excavate the soil near the axis of rotation of the rotor of a straight-flow rotary ripper, a small rotor with a higher angular velocity should be installed, coaxially with a large rotor. The use of straight-flow rotary rippers for soil development is constrained by insufficient theoretical substantiation of their parameters. Before analysing the interaction of the elements of the working bodies of the straight-flow rotary ripper with the soil, it is necessary to clarify the structural layout of the small rotor.The method of research. The small rotor should contain two knives connected at the periphery by a disc to give rigidity to the knives; the cross-section of the knives is triangular with a sharpening angle of 20 °, for maximum transformation of the angle of sharpening, the knives must have a saber-shaped shape; two teeth located on the disk to loosen the soil and shift it towards the knives; a shaft tip of the small rotor, the diameter of which must exceed the width of the knife at the point of its connection with the shaft tip; a spiral knife at the end of the shaft tip to loosen the soil and shift it towards the knives. By constructing projections on the transverse-vertical plane of the blade of the knife, the tooth and the disc of the small rotor, when there is a different angle of deviation of the blade in the cutting plane, it is possible to identify the basic geometric parameters of the elements of the small rotor of the straight-flow rotary ripper. Applying the well-known formulas of theoretical mechanics, we will determine the angular velocity of the small rotor and other kinematic parameters.Results. Based on the method of constructing a projection on the transverse-vertical plane of the blade of a knife, a tooth and a disc of a small rotor, when there is a different angle of deviation of the blade in the cutting plane, the main geometric parameters of the elements of the small rotor of a straight-flow rotary ripper are revealed. According to the formulas of theoretical mechanics, the following are determined: the circumferential velocity of the point on the surface of the shaft, the angular velocity of the small rotor, the time of one revolution of the small rotor, the path of the unit for one revolution of the small rotor. The dependence of the radius of the point on the blade of the knife of the small rotor on the angle of rotation of the beam is constructed and approximated.Conclusion. By constructing projections on the transverse-vertical plane of the knife blade at different angles of deflection of the blade in the cutting plane the optimal shape of the knife blade has been determined, the transformation of the angle of sharpening of the blade depending on the angle of deviation of the cutting plane from the plane perpendicular to the blade, the front, back corner of the knife blade, the profile of the blade of the small rotor knife in space was revealed, a structural layout of the small rotor was made, the circumferential velocity of the point on the surface of the shaft, the angular velocity of the small rotor, the time of one revolution of the small rotor, the path of the unit for one revolution of the small rotor are calculated.

Experimental investigation of liquid metal droplet flow affected by a time-dependent magnetic field

Abstract The present study investigates experimentally the effects of a time-dependent and spatially inhomogeneous magnetic field on liquid metal droplet flow down an inclined substrate. The flow is solely excited by the electromagnetic interactions between the electrically conducting melt and the applied magnetic field. The metal droplet consists of the eutectic alloy GaInSn which is liquid at room temperature. The magnetic field is generated in the gap between two metallic disks that are equipped with a special geometric arrangement of permanent magnets and put into a measured rotation. During the experiments, a droplet of a measured volume is positioned on an electrically non-conducting substrate that is slightly inclined against the horizontal direction. Droplet and substrate are placed in between the two rotating magnetic disks. In our experiments, we record the electromagnetically excited flow of the droplet downwards onto the substrate using a high-speed camera system. Applying standard techniques of digital image processing, we measure both the displacement position and velocity of the droplet as a function of time. We observe that, depending on the rotation rate of the disks and angle of inclination, the magnetic field eventually triggers this spreading process. In more detail, by evaluating the recorded data, we find that the magnetic field excites capillary waves at the free surface of the droplet. These surface waves contribute to a redistribution of volume towards the contact line formed at the downward-facing end tip of the droplet. This mode of transport steepens the contact angle, allowing the droplet to move. Besides the fundamental aspect of this work, the present study may contribute to the electromagnetic control of both the production of metallic microfibers and metallurgic coating processes as well as to the non-contact electromagnetic flow measurement technique of Lorentz force velocimetry applied to liquid metal free-surface flows.

Numerical Investigation of Flow Around Finite Height Rectangular

Three-dimensional flow features of the slender rectangular prism with cross-section height (H) to streamwise depth (D) ratio or side ratio (D/H = 0.5) were investigated numerically using the Large-eddy simulations (LES) turbulence model with Reynolds number Re = 22000. Four different aspect ratios (L/H = 2.5 – 10) were employed in this research to study the effect of the spanwise variation of the prism model on the flow pattern around the prism. Moreover, the instability-induced motion of the prism was modeled to predict the alteration of flow characteristics of stationary to vibrating states of the test model. The global quantities such as drag force, pressure coefficient, and Strouhal frequency characteristics are presented, which suggests that the structure end tip effect plays an essential role in the dependency of flow features variation. The velocity vector variations at streamwise and spanwise positions are also demonstrated. The prism model with a small aspect ratio (L/H = 2.5) exhibited Karman vortex suppression at the prism's vicinity, and the streamwise vortices region shrank. The flow features of the vibrating prism show different behaviors from the stationary prism model

Monolithic integration of embedded III-V lasers on SOI

Silicon photonic integration has gained great success in many application fields owing to the excellent optical device properties and complementary metal-oxide semiconductor (CMOS) compatibility. Realizing monolithic integration of III-V lasers and silicon photonic components on single silicon wafer is recognized as a long-standing obstacle for ultra-dense photonic integration, which can provide considerable economical, energy-efficient and foundry-scalable on-chip light sources, that has not been reported yet. Here, we demonstrate embedded InAs/GaAs quantum dot (QD) lasers directly grown on trenched silicon-on-insulator (SOI) substrate, enabling monolithic integration with butt-coupled silicon waveguides. By utilizing the patterned grating structures inside pre-defined SOI trenches and unique epitaxial method via hybrid molecular beam epitaxy (MBE), high-performance embedded InAs QD lasers with monolithically out-coupled silicon waveguide are achieved on such template. By resolving the epitaxy and fabrication challenges in such monolithic integrated architecture, embedded III-V lasers on SOI with continuous-wave lasing up to 85 °C are obtained. The maximum output power of 6.8 mW can be measured from the end tip of the butt-coupled silicon waveguides, with estimated coupling efficiency of approximately -6.7 dB. The results presented here provide a scalable and low-cost epitaxial method for the realization of on-chip light sources directly coupling to the silicon photonic components for future high-density photonic integration.

Boosting the energy harvesting performance of cantilever structured magneto-mechano-electric generator by controlling magnetic flux intensity on magnet proof mass

A cantilever-structured magneto-mechano-electric (MME) generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks. Recently, the concept of a magnetic flux concentrator (MFC) to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced. However, the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam. Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator, optimizing the volume and position of the proof-mass with MFC is crucial for better performance. Furthermore, a smaller proof-mass is desirable for the long-term reliability of cantilever-type harvesters. Hence, we investigated the effect of the position and weight (volume) of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments. The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field, which was 210% of that of the MME configuration used in our previous study. Furthermore, the MME generator showed broadband characteristics around the practical frequency of 60 Hz, which could provide more freedom to design the harvester with high performance.

The Performance of Magnetostrictive Material for Wind-Induced Vibration Power Generator

This research investigated the effect of span length variation and capless prismatic structure on the performance of the micropower generator from flow-induced vibration. The vibration response type covers galloping and vortex-induced vibration regimes. The mini harvester energy induced by the harmonic oscillation of prismatic structure was implemented based on the magnetostrictive principle to gain electricity using a galfenol alloy (Fe-Ga). The power generation variations are influenced by the amplitude, frequency, structure displacement, span length, and shape of the bluff body. The optimum power generation is 2.87 mW, and the maximum power generation is 10.63 mW at the resonance velocity Vr of 6.45. Reducing the frequency characteristics of circular cylinders by applying a cap end tip affect power generation characteristics and galloping behaviour for the prism with a span length of 200 mm but not for other span lengths. The effect of span length variation on free vibration and power generation performance for all prism models is similar in that both features are decreased by increasing span length. However, it enhances onset valued power generation. Power generation is considered for the independent electricity supply for specific sensor or wireless devices of an IoT system.

Influence of gear–shaft interference fit assembly on the meshing characteristics of cylindrical gears considering comprehensive modifications

The interference fit assembly of shaft and gear has an important influence on the gear drive performance. In this work, the cylindrical gear active surfaces and fillet will be provided with comprehensive modifications including front and back end reliefs, tip and root reliefs, as well as a low-value lead crowning. The mathematical model of the gear flanks surfaces with the mentioned modifications has been developed. A finite element model of the gear set has been established to study the effect of the interference fit assembly of the gears with their shafts on the meshing characteristics of cylindrical gears with modified tooth surfaces. With the increment of the interference fit amount, the contact pattern is shifted towards the top edge of the gear flank. The increment of the interference fit amount also contributes to the shift of root stress distribution towards the root land of the tooth. The maximum value of root bending stress keeps a positive linear relationship with the amount of shaft–gear interference fit being considered.

Phase-field-crystal simulation of nano-single crystal microcrack propagation under different orientation angles

The propagation mechanism of microcracks in nanocrystalline single crystal systems under uniaxial dynamic and static tension is investigated using the phase-field-crystal method. Both dynamic and static stretching results show that different orientation angles can induce the crack propagation mode, microscopic morphology, the free energy, crack area change, and causing fracture failure. Crack propagation mode depends on the dislocation activity near the crack tip. Brittle propagation of the crack occurs due to dislocation always at crack tip. Dislocation is emitted at the front end of the crack tip and plastic deformation occurs, which belongs to ductile propagation. The orientation angles of 9° and 14° are brittle--ductile mixed propagation, while the orientation angles of 19° and 30° are brittle propagation and no dislocation is formed under dynamic tension. The vacancy and vacancy connectivity phenomenon would appear when the orientation angle is 14° under static tension, and the crack would be ductile propagation. While the orientation angle is 19° and 30°, the crack propagates in a certain direction, which is a kind of brittle propagation. This work has some practical significance in preventing material fracture failure and improving material performance.

Novel nano BaTiO3-based microwave vacuum treatment for precise and controllable scales stripping of wool fibers

Barium titanate nanoparticles were used as a locator to help accurately break the scales on the surface of wool fibers under microwave vacuum treatment, as an anti-felting process of wool with low environmental impact. The nanoparticles loaded by ultrasound are sandwiched between the scales and fibers, which allows the microwave energy concentration to break the scales for the shrink resistance of wool and avoid damaging the main body of fibers synchronously. The friction and mechanical properties of wool under microwave treatment with different power, temperature and processing time were discussed, morphological and chemical analysis of the fibers after treatment was also carried out. The results suggested that compared with the uncoated fibers, the anti-felting performance of the coated fibers after treatment had been significantly improved, while maintaining the mechanical properties, the tip end of the scales on the wool surface were cut off and the volume of the felting ball was increased by 82.3%. The nanoparticles coating the wool were also easily cleaned without residue. This study provided a novel potential approach in the modification of wool fibers for anti-felting.

Kinematic synthesis and simulation of a vegetable pot seedling transplanting mechanism with four exact task poses

To obtain a picking and planting integrated transplanting mechanism (PITM) with ideal trajectory shape, reasonable operating attitude, and compact structure for vegetable pot seedling transplanting, a symmetrical structural PITM composed of two planetary carriers and driven by a cam–noncircular gear combination mechanism was proposed in this paper. In accordance with the requirements of transplanting agronomy, the shape of the motion trajectory and the attitude of the end tip of the clamping claw at several specific positions (the starting and end points of picking seedling, the starting point of pushing seedling, and a special point on the return segment) were planned. To make the clamping claws of PITM pass through a set of prescribed positions, the mechanism was simplified to an open-chain 3R mechanism. An accurate four-position-based method for solving the open-chain mechanism model was adopted to obtain the curves of its fixed hinge point (central point) and dynamic hinge point (circle point). The ratio of adjacent bars’ lengths was analyzed to determine the feasible interval of the central and circle point curves and the reasonable link length. A desired closed transplanting trajectory that goes through the given points and the corresponding transmission ratio model of the open-chain mechanism was established. After the transmission ratio of each stage of gear and cam pairs was calculated and distributed, the prototype of PITM was designed and manufactured. Lastly, the effectiveness and feasibility of the design were verified through a preliminary experiment of the prototype. Keywords: kinematic synthesis, transmission ratio, non-circular gear, planetary carrier DOI: 10.25165/j.ijabe.20231602.6739 Citation: Sun L, Xu H C, Zhou Y Z, Shen J H, Yu G H, Hu H F, et al. Kinematic synthesis and simulation of a vegetable pot seedling transplanting mechanism with four exact task poses. Int J Agric & Biol Eng, 2023; 16(2): 85-95.

Diamondlike Carbon Surface Treatment Improves the Fatigue Resistance of Ultrasonic Tips

IntroductionThe aim of this study was to compare E1-Irrisonic (Helse Ultrasonics, Ocoee, FL) and Irri Black (Helse Ultrasonics), a novel ultrasonic tip with diamondlike carbon treatment, regarding their design, metallurgy, microhardness, bending resistance, and time to fracture under the oscillatory fatigue test. MethodsA total of 17 E1-Irrisonic and 17 Irri Black new ultrasonic tips were selected. The tip geometry and surface finishing were assessed using scanning electron microscopy. The elemental composition was defined by energy-dispersive X-ray spectroscopy. Hardness Knoop was calculated using a microhardness tester. The maximum load required to displace the instrument in 45° was recorded in gram/force, oscillatory fatigue was measured in seconds at the moment of instrument fracture, and the size of the separate fragments was determined in millimeters. The Student t test was used for statistical comparison (α = 5%). ResultsScanning electron microscopic analyses revealed that E1-Irrisonic had a flat end tip, whereas a noncutting rounded tip was observed in Irri Black. The surface of E1-Irrisonic was smoother than Irri Black, which was irregular. Energy-dispersive X-ray spectroscopic analyses showed that the elemental compositions of the E1-Irrisonic and Irri Black tips were consistent with stainless steel and titanium-aluminum alloys, respectively. Irri Black showed significantly higher bending load resistance, time to fracture under oscillatory motion, and hardness Knoop than the E1-Irrisonic tip (P < .05), whereas the length of fragments was similar (P > .05). ConclusionDiamondlike carbon treatment improved hardness Knoop and reduced the flexibility of the Irri Black ultrasonic tip, improving its time to fracture under oscillatory motion compared with the nontreated E1-Irrisonic tip.

A Novel Piezoelectric and Electromagnetic Energy Harvester as a High-Pass Filter With a Low Cutoff Frequency

Battery-less wireless sensor networks (BL-WSNs) are an interesting and sustainable solution for Internet-of-Things (IoT) applications. The sensor nodes in the BL-WSNs are often powered by an energy harvester. Generally, these harvesters provide intermittent energy to the BL-WSNs. Hence, to cater to a variety of applications, the energy harvesters should work as a high-pass filter, that is, provide continuous energy to the BLWSNs. This article proposes a novel design to harvest vibration energy using a coupled Dovetail-shaped piezoelectric and electromagnetic energy harvester (Dovetail-PEM-EH). Unlike earlier PEM-EH designs with either one or two vertical cantilevers, Dovetail-PEM-EH uses three bimorphs and one copper (fixed tip end) cantilever with magnets on the tips. Placing more than two cantilevers with tip magnets requires optimizing distances among cantilevers and selecting tip magnets in such a way that energy harvesting is increased and the design is stable, that is, cantilevers do not collide with each other. A low-complexity binary search-based algorithm is presented to achieve the same. By doing so, the magnetic attractive forces increase the vibration sensitivity of the proposed design, and it works as a high-pass mechanical filter with a low cutoff frequency. The detailed simulation analysis performed in COMSOL shows that there is a minimum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> increase in the voltage and six out of the nine tested models show more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> improvement in the harvested power when compared to the state-of-the-art. The hardware implementation of one of the models validates the simulation results with a slight variation.

Effect of Type of Motion on Torque Generated Intra-canally (in Vitro Study)

Objective: To measure cumulative torque values generated during different types of motions during instrumentation by rotary files. Method: Forty extracted human premolar teeth with single canal have been utilised, instrumentation was performed with a single-file procedure with tip end no. 25 and taperness of 6% by two groups of files; Protaper Gold and Wave One Gold. Each group was subdivided into two subgroups; Group A (10 in no.) set at 2.5 N.cm2. Group B (10 in no.) set at 1 N.cm2 using an endodontic motor. A software has been used for precise torque measurements of range of 0.05 N.cm2 for every 30 seconds. Results: The t test showed a highly significant difference between groups 1A and 2A (p≤.01). Cumulative torque also showed non-significant differences by the groups 1B and 2B, (p≥.05) (Table 2). Conclusion: At high torque setting, the preparation mode was affected by cumulative torque values whereas the same comparison was neutral at low torque control motor

Heroin detection in a droplet hosted in a 3D printed support at the miniaturized electrified liquid-liquid interface

Simple sensing protocols for the detection of illicit drugs are needed. Electrochemical sensing is especially attractive in this respect, as its cost together with the analytical accuracy aspires to replace still frequently used colorimetric tests. In this work, we have shown that the interfacial transfer of protonated heroin can be followed at the electrified water-1,2-dichloroethane interface. We have comprehensively studied the interfacial behavior of heroin alone and in the presence of its major and abundant cutting agents, caffeine and paracetamol. To maximally increase developed sensing protocol applicability we have designed and 3D printed a platform requiring only a few microliters of the aqueous and the organic phase. The proposed sensing platform was equipped with a cavity hosting a short section of Ag/AgCl electrode, up to 20 µL of the aqueous phase and the end of the micropipette tip being used as a casing of a fused silica capillary having 25 µm as the internal pore diameter. The volume of the organic phase was equal to around 5 µL and was present inside the micropipette tip. We have shown that under optimized conditions heroin can be detected in the presence of caffeine and paracetamol existing in a sample with 10,000 times excess over the analyte of interest. The calculated limit of detection equal to 1.3 µM, linear dynamic range spanning to at least 50 µM, good reproducibility, and very low volume of needed sample is fully in line with forensic demands.

Challenges in modeling the Agility multileaf collimator in treatment planning systems and current needs for improvement.

The Agility multileaf collimator (MLC) mounted in Elekta linear accelerators features some unique design characteristics, such as large leaf thickness, eccentric curvature at the leaf tip, and defocused leaf sides ('tilting'). These characteristics offer several advantages but modeling them in treatment planning systems (TPSs) ischallenging. The goals of this study were to investigate the challenges faced when modeling the Agility in two commercial TPSs (Monaco and RayStation) and to explore how the implemented MLC models could be improved in thefuture. Four linear accelerators equipped with the Agility, located at different centers, were used for the study. Three centers use the RayStation TPS and the other one uses Monaco. For comparison purposes, data from four Varian linear accelerators with the Millennium 120 MLC were also included. Average doses measured with asynchronous sweeping gap tests were used to characterize and compare the characteristics of the Millennium and the Agility MLCs and to assess the MLC model in the TPSs. The FOURL test included in the ExpressQA package, provided by Elekta, was also used to evaluate the tongue-and-groove with radiochromic films. Finally, raytracing was used to investigate the impact of the MLC geometry and to understand the results obtained for eachMLC. The geometry of the Agility produces dosimetric effects associated with the rounded leaf end up to a distance 20mm away from the leaf tip end measured at the isocenter plane. This affects the tongue-and-groove shadowing, which progressively increases along the distance to the tip end. The RayStation and Monaco TPSs did not account for this effect, which made trade-offs in the MLC parameters necessary and greatly varied the final MLC parameters used by different centers. Raytracing showed that these challenging leaf tip effects were directly related to the MLC geometry and that the characteristics mainly responsible for the large leaf tip effects of the Agility were its tilting design and its small source-to-collimatordistance. The MLC models implemented in RayStation and Monaco could not accurately reproduce the leaf tip effects for the Agility. Therefore, trade-offs are needed and the optimal MLC parameters are dependent on the specific characteristics of treatment plans. Refining the MLC models for the Agility to better approximate the measured leaf tip and tongue-and-groove effects would extend the validity of the MLC model, reduce the variability in the MLC parameters used by the community, and facilitate the standardization of the MLC configurationprocess.