Metal Rod Research Articles

Accurate Phase Calibration of Multistatic Imaging System for Medical and Industrial Applications

Multistatic imaging systems are commonly used in radar systems and microwave imaging. In these systems, many antennas are arranged three-dimensionally and connected to RF switches. The length of each transmitter (Tx) and receiver (Rx) channel differs slightly, causing artifacts in high-resolution image reconstruction. This study presents a novel method for the phase calibration of multistatic systems. This method does not require system reconstruction and can automatically perform phase calibration in a short time. This method is expected to facilitate an accurate phase measurement in multistatic systems. The approach involves phase calibration by analyzing the reflection coefficients of antenna elements in the time domain. Imaging experiments were performed on a multistatic imaging system using this calibration method, and the position and shape of a metal rod with a diameter one-fourth of a wavelength were reconstructed by simple back-projection with an accuracy beyond the diffraction limit.

SCIENTIFIC AND TECHNICAL SUBSTANTIATION OF THE PARAMETERS OF THE RADIOLOCATION DEVICE FOR THE DETECTION OF PROHIBITED ITEMS

The paper presents a scientific and technical substantiation of the parameters of the radar device, which allows to detect and visualize forbidden objects by means of electromagnetic radiation of the microwave range. A model of a multistatic scheme for measuring waves reflected from an object based on the holographic method is developed. A software complex of simulation modeling of radar device operation has been developed, by means of which reconstructions of object images for different configurations of sparse sensor subsystems of the radar device have been obtained. An optimal configuration of the sparse sensor subsystem was selected by the method of peak signal-to-noise ratio analysis, for which a multi static hologram was modeled and a reconstruction of the metal rod image was generated. The reconstruction of the metal rod image obtained as a result of simulation modeling has a recognizable contour, which confirms the prospect of developing an experimental prototype of a radar device for detecting prohibited objects.

Liquid state properties and amorphous solidification kinetics of multicomponent Fe_{50-x}Co_{x}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} alloys investigated under containerless processing conditions.

The liquid state thermophysical properties and amorphous solidification kinetics of Fe_{50-x}Co_{x}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} (x=10, 15, 20, and 25) alloys were explored by electromagnetic and electrostatic levitation techniques. It was found that the surface tension of liquid alloys with Fe contents below 30 at.% had a strong temperature dependence. The high surface tension led to a sharp increase in the interfacial free-energy penalty. A high nucleation barrier was formed inside the melt, which greatly inhibited the nucleation rate. The liquid viscosity revealed the strong liquid feature of this alloy series, which became the dominant kinetic factor determining their solidification mechanisms. The high viscosity hindered atomic diffusion and delayed nucleation. The long crystallizing incubation time of Fe_{30}Co_{20}Cr_{14}Mo_{14}C_{9}B_{8}Tm_{5} ensured a strong glass-forming ability and a low critical cooling rate of 2.11×10^{3}Ks^{-1}. As a result, a bulk metallic glass rod with an 8-mm diameter was successfully prepared by a convenient casting procedure. This rod could remain in a glassy state at a higher temperature and over a wider temperature range due to its high glass-transition temperature and large undercooled liquid region. The apparent activation energy for nucleation was derived as 463.8 kJmol^{-1} according to the nonisothermal crystallization kinetics, indicating that the bulk metallic glass had to absorb a large amount of energy to overcome the potential barriers before nucleation and thus exhibited excellent thermal stability.

Experimental detection of mechanical deformations exploiting electromechanical effects

The present paper discusses experimental results concerning the deformation-induced generation of electric potential difference in steel specimens. According to our observations, voltages in the order of 10 microVolts can be measured between points on the surfaces of steel bodies during mechanical deformation. Three different experimental set-ups were used to determine the properties of the phenomenon, carefully excluding the influence of possible external electromagnetic fields. In order to exclude thermoelectric effects, a special steel specimen was fabricated. Further experimental campaigns were conducted with long, thin metallic rods in two different set-ups: the generation of voltage was measured during the traveling of longitudinal shock waves and during bending vibrations of the specimens. The results indicate that the variation of the magnetization of the material – the magnetoelastic effect – plays an important role in the phenomenon, but thermoelectricity also contributes to the measurable voltage signals. The electromechanical effect identified in the present paper may have several applications in measurement technology. The most relevant advantage of the applied measurement methods is that these are essentially sensor-free, since the mechanical vibrations can be detected by simply soldering, welding, or pressing copper wires to the examined steel specimen.

Determination of plasticity of mastic asphalt mixtures by the Luer method

Abstract. Problem. Mastic asphalt mixtures, unlike other types of asphalt concrete, have certain granulometric and technological features that necessitate the use of specific quality indicators. The most informative quality indicators for mastic mixtures are plasticity at service and process temperatures. Unlike the service plasticity indicator, which is widely used and standardized in most countries of the world, technological plasticity, despite its importance, is of limited use for assessing the quality of mastic mixtures. Goal. The aim of this work was to establish the possibility and feasibility of using the Luer method to assess the technological plasticity of mastic asphalt mixtures in the road industry of Ukraine. To achieve this goal, an appropriate device was manufactured and the experimental study of the plasticity of mastic asphalt mixtures using the Luer method was carried out. Methodology. The determination of plasticity by the Luer method consisted of immersing a metal rod with a hammer under its own weight in the mastic asphalt concrete mixture. The Luer yield strength is the time, with an accuracy of 1 s, during which the rod with a hammer is immersed in the mastic asphalt concrete mixture at a distance of 50 mm (from the lower to the upper mark). Experimental determination of the plasticity of mastic asphalt mixtures of different particle size distribution with different bitumen content was carried out. Results. On the basis of experimental data, the sensitivity of the Luer method to the particle size distribution of mastic asphalt mixtures and the amount of bitumen in the mixture was confirmed. During the experimental verification of the Luer method, its advantages and disadvantages were identified. The advantages include simplicity of the device design and relative speed of the test. The disadvantages of the method are a significant volume of mastic asphalt mixture required for the test; rapid cooling of the mixture and the rod, especially in the case of determining plasticity at high process temperatures, which affects the accuracy of assessing the plasticity of mastic mixtures. Practical value. Based on a production test of determining the plasticity of mastic asphalt mixtures by the Luer method, the possibility and feasibility of its use in the domestic road industry when designing mixtures and setting technological temperatures for their preparation, which ensure the production of mastic asphalt concrete whose properties meet the requirements of national regulations, has been confirmed

Evaluation of a Metal Artifact Reduction Algorithm for Image Reconstruction on a Novel CBCT Platform.

The presence of metal implants can produce artifacts and distort Hounsfield units (HU) in patient computed tomography (CT) images. The purpose of this work was to characterize a novel metal artifact reduction (MAR) algorithm for reconstruction of CBCT images obtained by the HyperSight imaging system. Three tissue-equivalent phantoms were fitted with materials commonly used in medical applications. The first consisted of a variety of metal samples centered within a solid water block, the second was an Advanced Electron Density phantom with metal rods, and the third consisted of hip prostheses positioned within a water tank. CBCT images of all phantoms were acquired and reconstructed using the MAR and iCBCT Acuros algorithms on the HyperSight system. The signal-to-noise ratio (SNR), artifact index (AI), structural similarity index measure (SSIM), peak signal-to-noise ratio (PSNR), and mean-square error (MSE) were computed to assess the image quality in comparison to artifact-free reference images. The mean HU at various VOI positions around the cavity was calculated to evaluate the artifact dependence on distance and angle from the center of the cavity. The artifact volume of the phantom (excluding the cavity) was estimated by summing the volume of all voxels with HU values outside the 5th and 95th percentiles of the phantom CBCT with no artifact. The SNR, AI, SSIM, PSNR, and MSE metrics demonstrated significantly higher similarity to baseline when using MAR compared to iCBCT Acuros for all high-density materials, except for aluminum. Mean HU returned to expected solid water background at a shorter distance from metal sample in the MAR images, and the standard deviation remained lower for the MAR images at all distances from the insert. The artifact volume decreased using the novel MAR algorithm for all metal samples excluding aluminum (p<0.001) and all hip prostheses (p<0.05). Varian's HyperSight MAR reconstruction algorithm shows a reduction in metal artifact metrics, motivating the use of MAR reconstruction for patients with metal implants.

Evaluation of Neuroprotective Effects of Local Hypothermia in a Porcine Spinal Cord Injury Model

Abstract The goal of this study was to assess the therapeutic potential of a 5-hour local spinal cord (SC) hypothermia by 4 °C saline on preservation of SC tissue at the injury epicentre and 3 cranial and caudal 10 mm long SC segments in a porcine experimental model of spinal cord injury (SCI). The SCI was inflicted through L3 laminectomy by a metallic rod moved by a velocity of 30 mm.sec−1, and operated by a computer-controlled apparatus. A group of 15 female minipigs 5‒8-month-old weighing 28‒35 kg was randomly divided into 5 subgroups (each composed of 3 animals): 1) sham controls; 2) SCI by force 8N; 3) SCI by force 8N, 5-hour hypothermia; 4) SCI by force 15N; 5) SCI by force 15N, 5-hour hypothermia. After a 9-week survival period, the minipigs were in deep general anaesthesia transcardially perfused by 5000 ml of saline and fixed by 5000 ml 4 % neutral paraformaldehyde. White and grey SC matter damage was evaluated in specimens cut from the epicentre of injury as well as 3 cranial and 3 caudal 10 mm long SC blocks dyed according to Luxol fast blue (LFB) with cresyl violet (CV) protocol for light microscopic observations. The percentage of preserved SC white and grey matter was assessed in microphotographs and compared with data from sham controls (considered 100 %). The data were statistically evaluated by ANOVA test, the difference P ˂ 0.05 was considered significant. Results of the study suggest that 5-hour local cooling of the epicentre of SCI is well tolerated and facilitates the preservation of SC tissue integrity. Additional experimental and preclinical studies are necessary before introducing the method in practice.

Hot probe technique for thin films Seebeck coefficient measurement

A new experimental method using a 50 μm diameter hand fabricated hot probe of Pt90/10Rh alloy is proposed as a tool to measure the Seebeck coefficient of thin films deposited onto electrically insulated substrates. A thermal model for heat transfer inside the probe and to the sample was developed to simulate the corresponding temperature distributions. Simulations showed that the ratio of the temperature rise in the contact point to the average temperature of the probe evolves basically independent on electrical current and film-substrate properties. Moreover, the values of contact radius and thermal contact resistance should not be necessary known, but only the pairs which are best fitting the probe thermal resistance in contact with the film-substrate. This brings a great simplification in respect with certain AFM based hot probe methods for which is necessary to determine these two parameters by calibration of the two substrates with known thermal conductivity. The values can be further used to evaluate the Seebeck coefficient of the sample with a macroscopic probe, within 1 % precision. By variance to the classical measuring methods, which resort to a heater-heat sink ensemble instrumented with thermocouples, heated metallic rods with built-in thermocouples or microfabricated structures, the proposed method is fast, reliable and of higher spatial resolution. The method was validated by measuring the Seebeck coefficient on CdS, Bi and Cr thin films reference samples, respectively.

Simultaneous Measurement of Conductivity and Diameter of an Infinite Length Metallic Rod Using the Phase Signature of Induced Eddy Current

Simultaneous Measurement of Conductivity and Diameter of an Infinite Length Metallic Rod Using the Phase Signature of Induced Eddy Current

The Influence of Structural Irregularity in Dielectric-tube-supported Metal Rod Transmission Line at THz Band

The Influence of Structural Irregularity in Dielectric-tube-supported Metal Rod Transmission Line at THz Band

Fractional-Order Interval Parameter State Space Model of the One-Dimensional Heat Transfer Process

In this paper, the new non-integer-order state space model of heat processes in a one-dimensional metallic rod is addressed. The fractional orders of derivatives along space and time are not exactly known, and they are described by intervals. The proposed model is the interval expanding of the state space fractional model of heat conduction and dissipation in a one-dimensional metallic rod. It is expected to better describe reality because the interval order of each real process is difficult to estimate. Using intervals enables describing the uncertainty. The presented interval model can be applied to the modeling of many real thermal processes in the industry and building. For example, it can describe the thermal conductivity of building walls. The one-dimensional approach can be applied because only the direction from inside to outside is important, and the heat distribution along the remaining directions is uniform. The paper describes the basic properties of the proposed model and supports the theory via simulations in MATLAB R2020b and experiments executed with the use of a real experimental laboratory system equipped with miniature temperature sensors and supervised by PLC and SCADA systems. The main results from the paper point out that the uncertainty of both fractional orders impacts the crucial properties of the model. The uncertainty of the derivative along the time affects only the dynamics, but the disturbance of the derivative along the length disturbs both the static and dynamic properties of the model.

Management of Corn Using Agnikarma

Corns (clavi) are a common painful condition caused by hyperkeratosis due to repetitive friction or pressure. Agnikarma, an Ayurvedic thermal cauterization technique, is traditionally used to treat various musculoskeletal and dermatological conditions. This case study evaluates the efficacy of Agnikarma in treating a corn on the sole of a patient's foot. Patient Profile: A 45-year-old male school teacher presented with a painful corn on the plantar aspect of her right foot. The corn had been persistent for six months, causing severe discomfort while walking or standing. The patient opted for Agnikarma after conventional treatments were discussed. Method: The corn was marked and the surrounding area cleaned. A heated Shalaka (metal rod) was applied to the corn in a circular motion to achieve a therapeutic burn. Post-procedure care included keeping the area clean and dry with regular dressing changes. Results: The patient experienced significant pain relief one week post-procedure, with the corn reducing in size by four weeks. By eight weeks, the corn had completely resolved with no recurrence or complications. The patient reported no discomfort and was able to resume normal activities. Conclusion: Agnikarma provided effective and immediate relief for the patient’s corn, showcasing its potential as a minimally invasive and cost-effective treatment. This technique promotes localized tissue necrosis and healing, making it a valuable alternative to conventional treatments, particularly for patients seeking prompt pain relief and reduced recurrence.

Surgical outcome of pediatric abdominal trauma at Tertiary Hospital, Northwest Ethiopia, a 3-year retrospective study

IntroductionAbdominal trauma in children is a significant health concern that often leads to severe complications and even death. Children experience trauma more frequently than adults, with approximately one in four pediatric patients suffering from serious abdominal injuries. Falls are the leading cause of such trauma among children, which is intriguing considering that most hospital admissions for pediatric abdominal injuries result from blunt force impacts.MethodA retrospective cross-sectional analysis of medical records was conducted to examine all patients under the age of 16 who underwent exploratory laparotomy for abdominal trauma between January 1, 2020, and January 1, 2023. The clinical data were gathered using a data extraction sheet from each patient’s medical charts. Information on socio-demographic characteristics, injury mechanisms, clinical conditions at the initial presentation, intraoperative findings and complications, and patient outcomes were collected.ResultsThe study involved a total of 90 patients, consisting of 72 males (80%) and 18 females (20%). The average age of the patients was 10, with a standard deviation of 4.7, ranging from 2 to 16 years. Half of the patients were below the age of 10, accounting for 46 individuals (51%). The causes of the injuries varied among patients below and above the age of 10. However, overall, bullet injuries were the most common cause, accounting for 28 cases (31%), followed by falls in 21 cases (23.3%), horse or donkey kicks in 10 cases (11.1%), stab injuries in 10 cases (11.1%), horn injuries in 7 cases (7.8%), and road traffic accidents in 6 cases (6.7%). Physical assault, blasts, and other types of injuries, such as hen bites and metal rod injuries, were observed in 8 cases (8.9%) of the patients. Fall accidents, horse or donkey kicks, and horn injuries were particularly more common among children below the age of 10, while bullet injuries and stab injuries were most common among those above the age of 10.ConclusionFollowing abdominal trauma in children, a range of complications may arise, including immediate issues such as infections and hemorrhaging, as well as long-term consequences like impaired organ functionality and psychological distress. In our region, young children are particularly vulnerable to accidents involving falls, kicks from horses or donkeys, and injuries caused by horns. Therefore, it is crucial to educate parents about these hazards. Additionally, providing appropriate guidance on firearm safety is essential for individuals who possess such weapons.

Stabilizacja zboczy podatnych na osuwiska za pomocą kotew rurowych

This paper presents an anchor of a new design, whose properties have been selected to retain the advantages of a tubular anchor over the other anchor types and at the same time, ensure its adaptation to specific conditions associated with slope stabilization. The proposed anchor consists of a steel tube filled with expanding cement mortar. The outer diameter of the tube is 2-3 mm less than the diameter of the borehole, a groove is cut on the outer surface of the tube. A metal rod is placed in the center of the tube at the outer end of which a support plate is installed, and a tie wrench is fixed. The length of the metal rod is equal to the depth of the bore hole, while the length of the steel tube is at least half the length of the borehole. In the process of solidification and expansion of the solution, pressure is created on the walls of the bore hole. Under the influence of pressure, the pipe is opened around the groove and close contact is achieved between the pipe and the borehole surfaces. As soon as the solution hardens, the steel tube is firmly embedded in the concrete, after which the anchor reaches operational capacity. Preliminary tests of the proposed anchor showed that it has a high clamping force (for hard rock conditions - 46-75 kN/m and for soft rock conditions 32-36 kN/m). He has other advantages, namely it does not require special equipment for installation, the inside of a tube is filled with hard concrete-like mass, which hampers the process of corrosion and increases shear strength.

Laser desorption mass spectrometry of rubrene and photodissociation of its cation

Laser desorption mass spectrometry was employed to study rubrene using three different sample preparation methods. Pressed-pellet and films drop-cast from solution were investigated with a laser-desorption time-of-flight spectrometer. Jet-cooled rubrene cations were produced in a supersonic molecular beam by laser desorption from a film-coated metal rod and detected with time-of-flight mass spectrometry. The films for this process were produced by vacuum sublimation of powder samples. The mass spectra from each of these samples contained the parent molecular ion and fragments resulting from phenyl ring elimination - a pattern similar to that produced by electron impact ionization. The amount of fragmentation varied with sample preparation and desorption laser wavelength. The rubrene cation was mass selected and studied with UV laser photodissociation at 355 nm. The resulting fragmentation mass spectrum indicated the loss of one or two phenyl groups, but no more than this. Computational studies of the ion energetics were used to investigate the stable fragment ion structures and understand the energetics of the dissociation process.

Bile acids differentially regulate longitudinal smooth muscle contractility in everted mouse ileum.

Bile acids regulate gastrointestinal motility by mechanisms that are poorly understood. Standard isolated tissue bath assays might not recapitulate invivo physiology if contractile responses to certain bile acids require direct application to the intestinal mucosa. We sought to determine the feasibility of quantifying longitudinal smooth muscle contractile responses to bile acids from intact segments of everted mouse ileum. Ileum from adult female C57BL/6J mice was isolated, gently everted over a notched metal rod, and mounted in tissue baths. Individual bile acids and agonists of bile acid receptors were added to the baths, and longitudinal smooth muscle contractile responses were quantified by isometric force transduction. Ursodeoxycholic acid robustly increased contractile responses in a dose-dependent manner. Deoxycholic acid stimulated contractility at low doses but inhibited contractility at high doses. Chenodeoxycholic acid, glycocholic acid, and lithocholic acid did not alter contractility. The dose-dependent increase in contractility resulting from the application of ursodeoxycholic acid was recapitulated by INT-777, an agonist of the Takeda G protein-coupled receptor 5 (TGR5), and by cevimeline, a muscarinic acetylcholine receptor agonist. Agonists to the nuclear receptors farnesoid X receptor, glucocorticoid receptor, pregnane X receptor, vitamin D receptor, and to the plasma membrane epidermal growth factor receptor did not modify baseline contractile patterns. These results demonstrate that gentle eversion of intact mouse ileum facilitates the quantification of longitudinal smooth muscle contractile responses to individual bile acids. Prokinetic effects of ursodeoxycholic acid and low-dose deoxycholic acid are replicated by agonists to TGR5 and muscarinic acetylcholine receptors.

S-shaped cheek-pieces from burial mounds of the nomads of the Scythian period in the Southern Urals

The article is devoted to the presentation of the typology of cheek-pieces used by the nomads of the Southern Urals in the VI–IV centuries BC and received the name S-shaped in special archaeological works. The relevance of the development is due to a significant increase in the number of cheek-pieces of various shapes found in mounds that were studied in the territory of the specified region. The number of these pieces of horse harness currently published in the scientific literature is about 200. The S-shaped cheek-pieces discussed in the article are metal rods with two holes in the body for fastening to a rein and ends bent in opposite directions at an angle to the central part. The development is based on the typology published by K.F. Smirnov in 1961, who considered S-shaped cheek-pieces as one type, represented by three options. The types were identified based on a set of characteristics that formed specific combinations and characterized the material from which the cheek-piece was made, the general configuration of the object, as well as the nature of its decoration. A sample of 57 specimens of these bridle parts was used to write the article. It is proposed to distinguish 6 types of two-hole S-shaped cheek-pieces. The dates proposed by researchers for the burial complexes containing these objects made it possible to establish the time of existence of each type among the South Ural nomads. Nomads of the Southern Urals used such cheek-pieces from the end of the 6th to the 4th centuries BC inclusive. The article examines the features of the spatial distribution of types represented by the largest number of copies.

Digital Evaluation of Trueness and Precision of Modern Impression Materials in Implant- Retained Mandibular Overdentures.

The purpose of this in vitro study was to evaluate the dimensional accuracy, trueness, and precision of vinyl siloxane ether (VSXE) and polyvinylsiloxane (PVS) impression materials using different impression techniques. A three-dimensional (3D) printed mandibular model with implants and metal rods served as the reference model. Impressions were taken in custom trays, resulting in four groups: PVS-closed-tray, VSXE-closed-tray, PVS-open-tray, and VSXE-open-tray. The reference model and impressions were scanned and analyzed using 3D analysis software to assess the trueness and precision within each group. There was significant difference in trueness between the groups, with PVS closed tray showing a higher deviation than VSXE-closed-tray and PVS-open-tray. VSXE-open-tray had the lowest deviation, which was statistically significant. In terms of precision, PVS-closed-tray showed the highest deviation, while no significant differences were found among the other groups. VSXE impression material with an open tray technique consistently demonstrated the highest levels of accuracy and precision. Conversely, PVS impression material with a closed tray technique yielded less favorable results. Better understanding of trueness and precision of new impression materials with new impression techniques will increase their clinical effectiveness.

A unique case of suicide by crossbow with indirect triggering and cranial injury: forensic issues and literature review.

Currently, crossbows are involved in some deaths, including suicides. These are rare events for which an accurate study of the body discovery site and reconstruction of the triggering mechanism of the crossbow represent crucial medicolegal elements. In this report, a unique case of suicide by crossbow is presented, in which the male victim constructed an elaborate scenario. He arranged two tripod stands to hold the crossbow at the height of his head, and a third to support a hollow tube positioned in front of the muzzle of the crossbow to direct the bolt. After positioning the center of the forehead in front of the hollow tube, the trigger was activated from a distance using a hooked metal rod. The methods used prompted a literature review on suicide by crossbow, which revealed only 14 reports from 1993 to 2023. The head and chest were the main target areas, and in almost all cases, the victims directly pulled the trigger with their finger. Only one case of indirect triggering was found, with the chest as the target. Therefore, in this scenario, the case presented stands as a unique report, due to the elaborate system devised to carry out the suicide and accurately strike the predetermined target.

Robustness and Tunability of Symmetric‐Protected Bound States in the Continuums and Quasi‐Bound States in the Continuums in Terahertz Metasurfaces

Symmetry‐protected bound states in the continuum (BICs), emerging at the point in the Brillouin zone of periodic lattices of scatters, are robust optical modes under modifications in the lattice if the C2 symmetry (two fold rotational symmetry) is preserved. In this study, the manipulation of these symmetry‐protected BIC and quasi‐BIC modes in a system comprising two metallic rods per unit cell by adjusting their lateral separation and displacement is focused on. With non‐symmetric systems under 180° rotation, two distinct coupling mechanisms resulting from changes in the lateral separation are investigated: the coupling of two half‐wavelength (λ/2) resonances and the coupling of two surface lattice resonances (SLRs). Notably, symmetric structures with minimal lateral separation cannot sustain BIC modes owing to the near‐field coupling between the rods. However, when the lateral separation is sufficiently large, the existence of a BIC mode supported by an SLR remains robust even with positional shifts. Furthermore, increasing the lateral separation and the shift displacement between the rods in asymmetric systems induces a redshift and a blueshift in the quasi‐BIC mode, respectively. This shift is attributed to the near‐field coupling effect between two rods, enabling the tunability of the resonance frequency with a high‐quality factor.