Needle Structure Research Articles

Development of recommendations on cooling rates of railway wheels with the use of modeling in the software package qform vx 8.2 for the formation of a homogeneous ferritic-perlite structure

The tests were performed on ER7 steel according to EN 13262. Based on the hardenability test (GOST 5657) by the method of end hardening (Jomen) the distance from the surface from which unilateral cooling was performed, where the hardness met the requirements of regulatory documentation for wheels of test steel, and the distance where the formation of needle structures, including bainite and otmanshtette, no longer took place. Simulation was applied in the software package QForm VX 8.2, as a result, a model was developed, for the adaptation of which the results of the experiment were used. Confirmed the high convergence of the results of the calculation and the experiment. At the same time, the model allowed to obtain an instantaneous cooling rate in a form that is more in line with the physical meaning of the process and to avoid the scatter of actual values associated with the discreteness of data capture. It is established that the instantaneous cooling rate changes in the process of continuous uniform supply of the cooler. The permissible range of cooling rates of the surface and central sections of the wheel rim during accelerated cooling of ER7 steel is determined. The data can be used to improve the heat treatment modes of railway wheels of current production in order to achieve a high set of mechanical properties both with the existing cooling technology and with differentiated cooling on the modernized equipment of the thermal section of the wheel shop. The developed model can be used to build thermokinetic diagrams under continuous cooling and to develop recommendations for heat treatment modes to achieve the specified mechanical properties under a certain structural state.

Simultaneous Measurement of Temperature and Refractive Index Using High Temperature Resistant Pure Quartz Grating Based on Femtosecond Laser and HF Etching.

The optical fiber temperature and refractive index sensor combined with the hollow needle structure for medical treatment can promote the standardization of traditional acupuncture techniques and improve the accuracy of body fluid analysis. A double-parameter sensor based on fiber Bragg grating (FBG) is developed in this paper. The sensor materials are selected through X-ray diffraction (XRD) analysis, and the sensor sensing principle is theoretically analyzed and simulated. Through femtosecond laser writing pure silica fiber, a high temperature resistant wavelength type FBG temperature sensor is obtained, and the FBG is corroded by hydrofluoric acid (HF) to realize a high-sensitivity intensity-type refractive index sensor. Because the light has dual characteristics of energy and wavelength, the sensor can realize simultaneous dual-parameter sensing. The light from the lead-in optical fiber is transmitted to the sensor and affected by temperature and refractive-index; then, the reflection peak is reflected back to the lead-out fiber by the FBG. The high temperature response and the refractive index response of the sensor were measured in the laboratory, and the high temperature characteristics of the sensor were verified in the accredited institute. It is demonstrated that the proposed sensor can achieve temperature sensing up to 1150 °C with the sensitivity of 0.0134 nm/°C, and refractive sensing over a refractive range of 1.333 to 1.4027 with the sensitivity of −49.044 dBm/RIU. The sensor features the advantages of two-parameter measurement, compact structure, and wide temperature range, and it exhibits great potential in acupuncture treatment.

Needle- and cross-linked ZnO microstructures and their photocatalytic activity using experimental and DFT approach

Thermal oxidation is a simple and cost-effective method that allows the production for large-scale of ZnO microstructures. By modifying the etching conditions (with HNO3) of the precursor, the morphology of the as-oxidized samples can be controlled, giving way to needle- and cross-linked ZnO microstructures. Electron microscopy results revealed that the (100) are dominating planes in the cross-linked structures, while the (101) are dominating planes in the needle structures. Density functional theory studies demonstrated that the ZnO interaction with HNO3 is a selective process which depends on the ZnO surfaces involved, whereas the reactivity of such surfaces can be attributed to the p orbitals associated with oxygen. Finally, photocatalytic results proved that these ZnO microstructures can be applied to degrade organic pollutants; i.e., methylene blue.

A whole area scanning-enabled direct-counting strategy for studying blocking efficiency in mitigating protein-solid surface binding.

The study of protein-solid surface binding as well as blocking efficiency of blocking agents plays an important role in the development of high-performance immunoassays. Although conventional colorimetric based assays are widely employed to monitor protein non-specific binding on the surface of microplate wells and evaluate the performance of blocking agents, there is still a great need to develop new methods to achieve the same goal from a new perspective. In this study, an innovative whole area scanning (WAS)-enabled direct-counting strategy was developed and validated through studying the blocking efficiency of different blocking agents on the non-specific binding of streptavidin-alkaline phosphatase conjugate (Strep-ALP, a model protein) to the surface of 96-well microplates. After non-specific binding of Strep-ALP in wells with or without blocking agents' treatment and loading of ELF™ 97 phosphate (ELFP), ALP in Strep-ALP conjugates converts ELFP to water-insoluble ELF™ 97 alcohol (ELFA), which precipitates locally, self-assembles into large needle structures, and glows green fluorescence upon excitation. After quenching the reaction, WAS of the whole wells allows us to directly count the number of individual fluorescent precipitates, which can be used to calculate and compare the blocking efficiency of three commonly used blocking agents (BSA, casein, and dry milk) based on mitigating the non-specific binding of Strep-ALP. WAS-enabled counting of individual needle-type precipitates opens a new avenue to investigate protein-solid surface binding as well as the efficiency of blocking agents with high sensitivity.

Numerical simulation of stable electrohydrodynamic cone-jet formation and printing on flexible substrate

This study aimed to regulate the stability of electrohydrodynamic cone-jet morphology by modifying the needle structure and conical point electrode by drawing upon high AC voltage and low flow velocity values. Accordingly, stability is achieved by the electrohydrodynamic jet (E-Jet) printing, considered an effective tool in micro and nanofabrication for flexible electronic systems. In the present study, 2-phase-field method was employed to draw a comparison of the volume of fraction method to optimize parameters for stable cone-jet on a PET substrate surface by exploiting a range of copper control electrodes. With COMSOL Multiphysics software, the equations of electric potential and electrical body forces were successfully solved. The validation study was compared with ensure the optimization parameters of cone-jet morphology, as retained in the boundaries of Melcher-leaky dielectric model. Moreover, the simulation parameters were directly adopted to print continuous line patterns on the PET substrate, which are considered prominent and promising E-Jet printing methods for flexible electronic systems.

Location, selection, and comparative anatomy of "Taixi" (KI3), "Shuiquan" (KI5), "Fuliu" (KI7), "Jiaoxin" (KI8), "Zhubin" (KI9), and "Yingu"(KI10) acupoints in rabbits

To investigate the. for locating and selecting the acupoints of "Taixi" (KI3), "Shuiquan" (KI5), "Fuliu" (KI7), "Jiaoxin" (KI8), "Zhubin" (KI9), and "Yingu" (KI10) and the morphological structure of these acupoints in rabbits. MethodsAccording to the WHO and national standards for human acupoints and rabbit X-ray images, acupoint locations were marked using the anatomical landmarks on body surface in 10 New Zealand rabbits. The acupoints were dissected to compare the homologous and analogous tissue between rabbits and human body and thus correct the locations of these acupoints. Potentials were measured for the 10 New Zealand rabbits at the corrected locations of the acupoints and around the acupoints, and the final locations of these acupoints were determined by comparing the anatomical results and the data of potentials. Anatomical observation was performed after marking, and the relationship between acupuncture needle and adjacent structure was observed. "Taixi" was located in the ankle area, at the midpoint between the prominence of the medial malleolus and the calca-neal tendon; "Shuiquan" was located in the calcaneal area below "Taixi" in the depression anterior to the calcaneal tuberosity; "Fuliu" was located at the medial side of the calf, at 2 cun above the prominence of the medial malleolus anterior to the calcaneal tendon; "Jiaoxin" was located at the medial side of the calf, at 2 cun above the prominence of the medial malleolus and in the depression posterior to the medial border of the tibia; "Zhubin" was located at the medial side of the calf, at 5 cun above the medial malleolus on the line between "Taixi" and "Yingu"; "Yingu" was located at the medial side of the knee, at the posterior-inferior border of the semitendinosus tendon on the popliteal crease. The results of skin potentials at the acupoints suggested that "Taixi", "Shuiquan", "Fuliu", and "Zhubin" were high-reliability acupoints, "Jiaoxin" was a medium-reliability acupoint, and "Yingu" was a low-reliability acupoint. Comparative anatomy combined with imaging, surface anatomy, and electrophysiological techniques of acupoints can help with the accurate localization and selection of acupoints in experimental animals, improve the reliability of acupoint location, and enrich the comparative anatomical data of acupoints.

Influence of template agent on NiMoO4 for high-performance hybrid energy storage devices

Here, NiMoO4 was successfully synthesized via a mild hydrothermal method combined with annealing treatment. The effects of nickel sources and Tween 80 on the morphology and electrochemical performance of NiMoO4 electrode for hybrid energy storage device were investigated in detail. When nickel sulfate as a nickel source, NiMoO4 exhibited a one-dimensional needle structure and reached the best specific capacity of 498 C g−1 at 1 A g−1. Moreover, the different dosages of Tween 80 all improved the morphology and capacity of one-dimensional needle NiMoO4. When the dosage was 0.005 mol, NiMoO4 nanorods formed a flower-like morphology and a higher specific capacity of 754 C g−1. Furthermore, we used the optimized NiMoO4 assembled a hybrid device which reached 68.36 Wh kg−1 at a power density of 923 W kg−1.

Anomalously Large Assembly Formation of Polystyrene Nanoparticles by Optical Trapping at the Solution Surface.

We demonstrated the optical trapping-induced formation of a single large disc-like assembly (∼50 μm in diameter) of polystyrene (PS) nanoparticles (NPs) (100 nm in diameter) at a solution surface. Different from the conventional trapping behavior in solution, the assembly grows from the focus to the outside along the surface and contains needle structures expanding radially in all directions. Upon switching off the trapping laser, the assembly disperses and needle structures disappear, while the highly concentrated domain of the NPs is left for a while. The single assembly is quickly restored by switching on the laser again, where the needle structures are also reproduced but in a different way. When a single 10 μm PS microparticle (MP) is trapped in the NP solution, a single disc-like assembly containing needle structures is similarly prepared outside the MP. Based on backscattering imaging and tracking analyses of the MP at the solution surface, it is proposed that scattering and propagation of the trapping laser from the central part of the NP assembly or the MP lead to this new phenomenon.

Numerical simulation of electrohydrodynamic jet and printing micro-structures on flexible substrate

This paper aims to present the simulation work and obtain optimized parameters for the development of drop-on-demand electrohydrodynamic jet (DoD E-Jet) to print control and stable micro-structures on a flexible insulating substrate. In this work, the novel comparison of three types of combination needle structures was developed based on the multiphase flow (liquid–air) technique, in order to achieve optimal printing conditions for a flexible PET substrate. According to simulation results, steel-quartz needle combination provides very unique compensations in the controllability and stability of E-Jet. Printing on a flexible substrate was challenging, but parameters used in simulation validate the possibilities for DoD E-Jet printing method. Optimize working parameters were achieved by the numerical simulation executed to generate developed and stable E-Jet morphology. In addition, various stable and uniform microscale droplets and structures were directly printed on a flexible polymer substrate with the help of collective impact of electrical force, viscous force, and internal pressure force throughout DoD E-Jet printing process. The results of numerical simulation and experimental work exhibited an excellent and promising E-Jet printing tool for flexible electronic systems.

SH-synthesis of alumino-manganese alloy based on the Al-MnO3 system

The work is devoted to the use of self-propagating high-temperature synthesis for producing aluminum-manganese alloy in the MnО3 AI system. The experiment was carried out in a specially designed SHS reactor at various pressures with and without preliminary heating. The synthesized samples were studied by X-ray diffraction, metallographic, and X-ray spectral analysis; compression tests were performed. X-ray powder diffraction data showed the presence of intermetallic compounds of different stoichiometries: Al8Mn5, Al11Mn4, and Al6Mn. It was established that the main phase is the Al8Mn5 intermetallic compound. The structure of the sample has a needle structure. The alloy has a high hardness of structural components: from 624 HV to 934 HV.
 High compressive strength and high hardness are evidence that the synthesized alloy is a direct competitor to hard alloys.

Transcriptional Downregulation of a Type III Secretion System under Reducing Conditions in Bordetella pertussis.

Bordetella pertussis uses a type III secretion system (T3SS) to inject virulence proteins into host cells. Although the B. pertussis T3SS was presumed to be involved in host colonization, efficient secretion of type III secreted proteins from B. pertussis has not been observed. To investigate the roles of type III secreted proteins during infection, we attempted to optimize culture conditions for the production and secretion of a type III secreted protein, BteA, in B. pertussis We observed that B. pertussis efficiently secretes BteA in ascorbic acid-depleted (AsA-) medium. When L2 cells, a rat lung epithelial cell line, were infected with B. pertussis cultured in the AsA- medium, BteA-dependent cytotoxicity was observed. We also performed an immunofluorescence assay of L2 cells infected with B. pertussis Clear fluorescence signals of Bsp22, a needle structure of T3SS, were detected on the bacterial surface of B. pertussis cultured in the AsA- medium. Since ascorbic acid is known as a reducing agent, we cultured B. pertussis in liquid medium containing other reducing agents such as 2-mercaptoethanol and dithioerythritol. Under these reducing conditions, the production of type III secreted proteins was repressed. These results suggest that in B. pertussis, the production and secretion of type III secreted proteins are downregulated under reducing conditions.IMPORTANCE The type III secretion system (T3SS) of Bordetella pertussis forms a needlelike structure that protrudes from the bacterial cell surface. B. pertussis uses a T3SS to translocate virulence proteins called effectors into host cells. The culture conditions for effector production in B. pertussis have not been investigated. We attempted to optimize culture medium compositions for producing and secreting type III secreted proteins. We found that B. pertussis secretes type III secreted proteins in reducing agent-deprived liquid medium and that BteA-secreting B. pertussis provokes cytotoxicity against cultured mammalian cells. These results suggest that redox signaling is involved in the regulation of B. pertussis T3SS.

In-situ development of a sandwich microstructure with enhanced ductility by laser reheating of a laser melted titanium alloy

Metallic additive manufacturing, particularly selective laser melting (SLM), usually involves rapid heating and cooling and steep thermal gradients within melt pools, making it extremely difficult to achieve effective control over microstructure. In this study, we propose a new in-situ approach which involves laser reheating/re-melting of SLM-processed layers to engineer metallic materials. The approach involves alternate laser melting of a powder layer at a high laser power and laser reheating of the newly formed solidified layer at a low or medium laser power. This strategy was applied to Ti-6Al-4V with a range of laser powers being used to reheat/re-melt solidified layers. It was found that the SLM-processed sample without undergoing laser reheating consist of a pure martensitic needle structure whereas those that were subjected to laser reheating/re-melting all consist of horizontal (α + β) bands embedded in martensitic α′ matrix, leading to development of a sandwich microstructure in these samples. Within the (α + β) bands, β exist as nano-sized precipitates or laths and have a Burgers orientation relationship with α matrix, i.e., {0001}⍺//{110}β and ⟨11stackrel{-}{2}0⟩⍺//⟨111⟩β. The width of (α + β) banded structure increased first with increased laser power to a highest value and then decreased with further increased laser power. With the presence of these banded structures, both high strengths and enhanced ductility have been achieved in the SLM-processed samples. The current findings pave the way for the novel laser reheating approach for in-situ microstructural engineering and control during metallic additive manufacturing.

Instrinsic relationship among needle morphology, anatomy, gas exchanges and tree growth across 17 Picea species

The genus Picea has wide geographical range and includes species with great economic and ecological value in the northern hemisphere. Growth traits, gas exchange parameters and needle morphology and anatomy vary greatly among Picea species, but the instrinsic relationship among these traits has not been well studied for the genus Picea. We thus conducted a common garden experiment to study the relationship for these traits in 13 native and 4 exotic Picea species growing at an experimental site in Tianshui, Gansu, China. Nearly all of these traits were significantly different among the 17 species and most traits were under relatively strong genetic control. The four species introduced from abroad (P. abies, P. pungens, P. glauca and P. mariana) exhibited good growth performance in the experimental site. We found that the growth traits showed significantly positive correlation with branching characteristics. Moreover, the species with good growth performance had a relatively high photosynthetic rate. The correlation analysis based on needle morphological and anatomical traits revealed that needle traits were interrelated and needle anatomical traits might be impacted by needle size due to the increase of mesophyll area and central cylinder area with needle length. Furthermore, the relationship between needle structures and gas exchange parameters may indicate that a higher photosynthetic rate can be attributed to variations in needle structures. In addition, both the cluster analysis and principal component analysis based on needle morphology, anatomy, gas exchanges and growth traits might partially reflect the evolutionary history of the 17 Picea species. Our study represents a comprehensive survey of variation within the genus Picea to date and opens new avenues for exploring the instrinsic relationship among growth traits, needle gas exchange and needle morphology and anatomy.

Enterohaemorrhagic Escherichia coli activates nitrate respiration to benefit from the inflammatory response for initiation of microcolony-formation

BackgroundFor successful colonization, enterohaemorrhagic Escherichia coli (EHEC) injects virulence factors, called effectors, into target cells through the type three secretion system (T3SS), which is composed of a needle and basal body. Under anaerobic conditions, the T3SS machinery remains immature and does not have a needle structure. However, activation of nitrate respiration enhances the completion of the T3SS machinery. Because nitric oxide released by the host inflammatory response increases nitrate concentration, we sought to determine the effect of the inflammatory response on initiation of EHEC microcolony-formation.ResultsThe colony-forming capacity was increased in accordance with the increase of nitrate in the medium. The addition of the nitric oxide-producing agent NOR-4 also enhanced the adherence capacity, which was dependent on nitrate reductase encoded by the narGHJI genes. Culture supernatant of epithelial cells, which was stimulated by a cytokine mixture, enhanced the colony-forming capacity of wild-type EHEC but not of the narGHJI mutant. Finally, colony formation by wild-type EHEC on epithelial cells, which were preincubated with heat-killed bacteria, was higher than the narGHJI mutant, and this effect was abolished by aminoguanidine hydrochloride, which is an iNOS (inducible nitric oxide synthase) inhibitor.ConclusionsThese results indicate that the inflammatory response enhances EHEC adherence by increasing nitrate concentration.

Thermal Transport of Hybrid Liquid over Thin Needle with Heat Sink/Source and Darcy–Forchheimer Porous Medium Aspects

The structure of needle is mostly similar as paraboloid of upset parallel to flow possesses and has huge applications in building and modern procedures including microstructure electronic gadgets and microscale cooling gadgets for thermal evacuation application. Based on these applications, an axisymmetric Darcy–Forchheimer flow and energy transport of hybrid nanoliquid over a slender moving needle is considered. Impact of heat sink/source and Newtonian heating is inspected. The dimensional nonlinear administering partial differential equations (PDEs) are modified to dimensionless nonlinear ordinary differential equations (ODEs) with assistance of similarity technique which is then explained numerically utilizing Runge–Kutta–Fehlberg scheme from Dsolve code MAPLE. It ought to be noticed that approval of results shows a decent concurrence with previously existing reports. It is noticed that the enhancing Forchheimer number and porosity parameter increase the temperature.

The Effect of Copper Content on the Mechanical and Tribological Properties of Hypo-, Hyper- and Eutectoid Ti-Cu Alloys.

Titanium alloys are widely used in aerospace, chemical, biomedical and other important fields due to outstanding properties. The mechanical behavior of Ti alloys depends on microstructural characteristics and type of alloying elements. The purpose of this study was to investigate the effects of different Cu contents (2.5 wt.%, 7 wt.% and 14 wt.%) on mechanical and frictional properties of titanium alloys. The properties of titanium alloy were characterized by tensile test, electron microscope, X-ray diffraction, differential scanning calorimetry, reciprocating friction and wear test. The results show that the intermediate phase that forms the eutectoid structure with α-Ti was identified as FCC Ti2Cu, and no primary β phase was formed. With the increase of Cu content, the Ti2Cu phase precipitation in the alloy increases. Ti2Cu particles with needle structure increase the dislocation pinning effect on grain boundary and improve the strength and hardness of titanium alloy. Thus, Ti-14Cu shows the lowest elongation, the best friction and wear resistance, which is caused by the existence of Ti2Cu phases. It has been proved that the mechanical and frictional properties of Ti-Cu alloys can be adjusted by changing the Cu content, so as to better meet its application in the medical field.

Solid‐state ion sensor for on‐chip determination of potassium ion in body fluid

AbstractThis article describes a synthetic route for the fabrication of all‐solid‐state potentiometric ion‐sensing device for on‐chip determination of potassium ion in body fluid. The sensing electrodes comprised of (a) a solid‐state reference electrode made from a Ag/AgCl‐printed electrode covered with a solid‐electrolyte‐embedded membrane made from siloxane polymer and (b) solid‐state ion‐selective electrode as working electrode made by assembling ionophore‐impregnated PVC membrane casting solution over a ion exchanger‐impregnated membrane. The ion exchanger‐impregnated membrane is cast by assembling siloxane–polyindole nanodispersion over working electrode of screen‐printed electrode to yield constant dipolar potential. The screen‐printed electrodes comprising of all‐solid‐state reference and working electrode can be operated under zero current flow to monitor potassium ion in given sample. The configuration of the printed electrodes is designed to fix a microneedle assembly over the working portion of both reference and working electrodes for transdermal ion sensing. The functional alkoxysilanes derived from nanodispersion allow to make solid‐state reference electrode avoiding the use of internal filling solution providing innovation in designing potentiometric sensor. In one aspect, a potentiometric device for detecting analyte in biological fluid that can include a array of hollowed microneedle in which each needle acts as protruded needle structure including an exterior wall forming a hollow interior covering both solid‐state working and reference electrode with an opening at terminal end in such that one microneedle is converted into a potassium ion‐selective electrode.

Compact 3D-Printed Active Flexible Needle for Percutaneous Procedures.

Needle-based intervention has been a popular procedure for diagnosis and treatment of many types of cancer. However, poor needle placement and tumor visualization have been among the challenges resulting in poor clinical outcomes. There has been a lot of progress in medical imaging technology, but the structure of surgical needles has remained unchanged. This work presents a wire-driven 3D steerable, 3D-printed active needle for improved guidance inside the tissue toward the target. The needle is manipulated by 3 embedded tendons via a programmed motorized control unit. Feasibility tests in a tissue phantom showed an average 3D needle angular deflection of about 11°. This amount of angular deflection is expected to assist prostate brachytherapy via a curvilinear approach.

Hierarchical structure of Five-shu points and Source-point of Triple Energizer Meridian in rabbits

To study the position and hierarchical structure of Five-shu points, i．e., "Guanchong" (TE1), "Yemen" (TE2), "Zhongzhu" (TE3), "Yangchi" (TE4) and "Zhigou" (TE6), and the Source-point "Tianjing" (TE10) of the Triple Energizer (TE) Meridian in the rabbit. Based on WHO Standard Acupuncture Point Locations in the Western Pacific Region (WHO Standard) and National Standard (GB/T 22103-2008) for Acupuncture Point Locations in human body, and combined with X-ray images, the hierarchical structure of Five-shu points and Source-point of the TE Meridian were observed in ten New Zealand rabbits. The acupoint locations were determined by comparing the same name tissues of the rabbits and human body after dissecting the above-mentioned acupoints. After inserting acupuncture needles into the aforementioned acupoints, the relationship between the acupuncture needle and adjacent structure were dissected and measured. "Guanchong" (TE1) was located on the lateral side of the 4th terminal phalanx, and behind the corner of the onyx root. When needled, the penetrated tissues of the acupuncture needle are skin, superficial fascia, deep fascia, and the root region of the 4th phalanx, respectively. "Yemen" (TE2) was located between the 4th and 5th onyxes, at the depression of intersection of coat hair superior to the fingerweb edge. When needled, the penetrated tissues of the acupuncture needle are the superficial fascia, deep fascia and lumbrical muscles of the forepaw, respectively. "Zhongzhu" (TE3) was located between the 4th and 5th metacarpal bones, at the depression proximal to the 4th metacarpophalangeal joint. When needled, the penetrated tissues are skin, superficial fascia, deep fascia, and lumbrical muscle, respectively. "Yangchi" (TE4) was positioned at the dorsal side of the forepaw, and the surface connection line between the accessory and radial bones intersected with the depression of the extensor digitorum communis on the ulnar side. When needled, the penetrated tissues are skin, superficial fascia, deep fascia, and the ulnar side of the common extensor tendon, respectively. "Zhigou" (TE6) was positioned between the radius and ulna, on the posterior aspect of the forelimb and 3 Bone-cun proximal to the distal dorsal forepaw crease. When needled, the penetrated tissues are skin, superficial fascia, deep fascia, and the extensor digitorum, respectively. "Tianjing" (TE10) was located at the junction of the body of humerus and the lateral condyle of humerus, on the posterior aspect of the elbow and proximal to the prominence of the olecranon. When needled, the penetrated tissues are skin, superficial fascia, deep fascia, and triceps brachii muscle, respectively. The Five-shu points and Source-point of the TE Meridian on the forelimb in rabbits are innervated by the cutaneous branches of the ulnar radial nerve and the medial brachial cutaneous nerve at the superficial layer, and by the branches of the ulnar nerve and radial nerve in the deep layer, accompanied with cephalic vein and forearm blood vessels and their branches.

Comparative Study of Microstructure, Mechanical and Reciprocating Wear Properties of Unmodified and Sr-Modified A383 Alloy and Composite

The present study focused on strontium (Sr)-induced A383 alloy and composite reinforced with 6 wt% boron carbide (B4C) particles processed by stir casting technique. From metallographic analysis, it was confirmed that Sr addition modified needle structures of α-Si to fine α-Si. This grain refinement enhanced the hardness of A383-Sr alloy by 52.72% and A383-Sr/B4C by 73.6%, and tensile strength of A383-Sr by 69.93% and A383-Sr/B4C by 81% when compared to A383 unmodified alloy. Fractography analysis proved that both Sr-induced alloy and composite had brittle failure with clear formation of flakes and cleavages. Reciprocating wear test was conducted at various loads (15 N, 25 N, 35 N) and at sliding distances (500 m, 1000 m, 1500 m). It was observed that wear rate was proportional to the applied load. Wear rate increased with increase in sliding distance, but after 1000 m, there was decline in wear rate. Worn surface analysis revealed the presence of oxide layer after 1000 m which enhanced wear resistance. A383-Sr/B4C composite possessed superior wear resistance compared to other.