Experimental analysis of microstructure and mechanical characteristics of LM6 & fly ash composite through stir casting method

Fly ash has received a lot of attention as a possible support for aluminium alloy composites (AMCs) to improve characteristics while lowering production costs. Al alloy MMC was made with different amounts of fly ash (2, 5, and 8%). The semi-solid state mould was gradually filled with reinforced particles. The optical microscope investigation of the microstructure of AMCs reveals homogenous fly ash dispensation. With the increase in fly ash particulate, the microstructure with refined composition displays reducing Si-needle structure and extending space of eutectic-Al grid space. While hardness increases by 88 percent, tensile strength increases by 57 percent and yield strength by 17 % of the AMCs with the increment of fly ash. The addition of fly ash particles improved the AMCs’ physical and mechanical qualities. As a result, it leads to upgrade the energy utilisation.

Structural, Morphological and Physical Properties of TiH2 Incorporated Hydroxyapatite

Titanium incorporated hydroxyapatite preparation was endeavored using TiH2. Titanium has good mechanical properties, good biocompatibility and bioactivity. Titanium incorporated hydroxyapatite material prepared for orthopedic applications were reported to be better mechanical properties. Hydroxyapatite (HAp) was synthesized by wet chemical facile method and after calcination was mixed with TiH2 (5 to 20%).The effect of sintering on phase formation, microstructure, density and porosity of Hap/TiH2was studied by sintering at temperatures from 900°C to 1200°C. The properties of the samples were characterized using X-ray diffraction technique (XRD), Scanning electron microscopy(SEM), Fourier transform spectroscopy (FT-IR), density and porosity. The results from studies showed the presence of β-tricalcium phosphate (β-TCP) and perovskite (CaTiO3) as the major crystalline phases; while minor reaction products like α-TCP and TTCP were also recorded for samples with higher amount of TiH2irrespective of sintering temperatures. Morphology evaluation by SEM revealed the presence of CaTiO3needle structure at temperature till 1000°C, above which it appeared hexagonal due to crystal growth. Functional groups, density and porosity were also studied.

Design and Experimental Evaluation of Mosquito-Inspired Needle Structure in Soft Materials

Insects steer their stingers effortlessly to a specific target and release their venom in a certain path through the skin with minimal pain. These unique traits inspire the idea to develop bioinspired needles to reduce the insertion forces and to decrease the needle path deviation (deflection) for improved targeting accuracy. Our approach in this work focus on the design of mosquito-inspired needle and evaluation of the needle performance using vibration during tissue insertion. The mosquito-inspired needle design specifically consists of maxilla-shaped and labrum-tip design. The insertion force was measured using a force sensor, which was fixed at the needle end to measure the uniaxial force of needles. The applied vibration on the needle was measured along linear axis using piezoelectric actuator with a frequency of 150 Hz and an amplitude of 5μm. The needle was inserted at a constant speed by attaching the needle to a motorized linear stage. It was observed that the insertion forces of the proposed needle design with vibration showed a reduction by 27% compared to that of a conventional needle. This reduction in insertion force means that there is decrease in tissue gel phantom damage and it was also observed that needle bending has reduced due to reduction in bending stiffness of the tissue phantom. Furthermore, the needle insertion tests in real tissues (bovine kidney) considering the proposed needle geometry and vibration will be studied in future work to understand the bioinspired needle-tissue interactions.

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.

Effect of Enhanced Squeezing Needle Structure on the Jetting Performance of a Piezostack-Driven Dispenser

Advanced dispensing technology is urgently needed to improve the jetting performance of fluid to meet the requirements of electronic product integration and miniaturization. In this work, an on–off valve piezostack-driven dispenser was used as a study object to investigate the effect of needle structure on jetting performance. Based on fluid dynamics, we investigated nozzle cavity pressure and jet velocity during the dispensing process using theoretical simulation for needles with and without a side cap. The results showed that the needle with a side cap had larger jet velocity and was capable of generating 8.27 MPa of pressure in the nozzle cavity, which was 2.39 times larger than the needle without a side cap. Further research on the influence of the nozzle and needle structural parameters showed that a nozzle conic angle of 85°–105°, needle conic angle of 10°–35°, and side clearance of 0.1–0.3 mm produced a dispenser with a large jet velocity and stable performance, capable of dispensing microscale droplets. Finally, a smaller droplet diameter of 0.42 mm was achieved in experiments using a glycerol/ethanol mixture, with a variation range of ± 4.61%.

Audio waves and its loss of energy in puncture needles

The location of a puncture needle’s tip and the resistance of tissue against puncture are crucial information for clinicians during a percutaneous procedure. The tip location and needle alignment can be observed by image guidance. Tactile information caused by tissue resistance to rupture, allow clinicians the perception of structural changes during puncture. Nevertheless, this sense is individual and subjective. To improve percutaneous procedures, the implementation of transducers to enhance or complement the senses offer objective feedback to the user. Known approaches are e.g. based on integrated force sensors. However, this is connected to higher device costs, sterilization and certification issues. A recent publication shows the implementation of an audio transducer clipped at the proximal end of the needle. This sensor is capable of acquiring emitted sounds of the distal tiptissue interaction that are transmitted over the needle structure. The interpretation of the measured audio signals is highly depended on the transmission over the needle, the tissue and, the penetration depth. To evaluate the influence of these parameters, this work implements a simplified experimental setup in a controlled environment with a minimum of noise and without micro tremors induced by clinician’s hands. A steel rod simulating a needle is inserted into pork meat of different thickness. A controlled impact covering the needle’s tip mimics tissue contact. The resulting signals are recorded and analyzed for better understanding of the system.