Dissimilar Rotary Friction Welding of Inconel 718 to F22 Using Inconel 625 Interlayer

Dissimilar metal joining has always been a challenging task because of the metallurgical incompatibility and difference in melting points of alloys being joined. Diffusion and mixing of alloying elements from dissimilar base metals at the weld often cause unwanted metallurgical changes resulting in unsuccessful welds or underperformance of the weldment. Solid-state dissimilar friction welds of Inconel 718 and F22 were prepared in this study with an Inconel 625 interlayer to address the carbon enrichment of Inconel 718 during the welding. Defect-free rotary friction welds were produced in this study. Microstructural and mechanical properties investigation of the weldments and base metals was carried out, and results were analysed. Intermixing zone was observed at the weld interface due to the softening of the metal at the interface and rotatory motion during the welding. The high temperatures and the plastic deformation of the intermixing zone and thermo-mechanically affected zone (TMAZ) resulted in the grain refinement of the weld region. The highest hardness was observed at the Inconel 718/F22 weld interface due to the plastic strain and the carbon diffusion. The tensile specimens failed in the F22 base metal for the weld prepared with and without the Inconel 625 interlayer. Inconel 718/F22 welds exhibited lower toughness values compared to the Inconel 718/F22 welds prepared with Inconel 625 interlayer.

Dynamic Modelling of Piston Slapping Motion in Combustion Engines

A numerical model of the piston skirt taking into account its lateral, reciprocating and rotatory motion has been presented in order to investigate the lateral motion of piston skirt assembly and resulting vibrations induced as a result of these motions in the engine block. Various parameters of modal analysis were obtained using mobility analysis. The presented methodology was validated by data obtained from a diesel engine test set up. The predicted results matched well with those of measured data, hence validating the presented scheme.

Identifying Physic Concepts in Yarn Production by None Fortress Society, Tetaf Village

Science learning is better related to nature through local wisdom since learners can gain more comprehension due to familiarity of occurring events through local wisdom based learning and they can preserve the local wisdom. This research aimed to identify physic concepts that occurred in the yarn processing using cotton by local society of None Fortress. The phenomenological design of qualitative research was undertaken in which the data triangulation technique comprised interviews, observation and documentation using an interview sheet, observation sheet and camera as instruments. The identification result of physic concepts in yarn production by None Fortress people covered Energy, Friction, Rotatory Motion, Circular Motion, Simple machine (Gear), Materials elasticity, vibration, measurement, capillarity, and radiation heat transfer. Based on the invented concepts, further research will expected to integrate the identification result in physic learning.

Scalable Bi-Directional SMA-Based Rotational Actuator

In industrial applications, rotatory motions and torques are often needed. State-of-the-art actuators are based on either combustion engines, electro-motors, hydraulic, or pneumatic machines. The main disadvantages are the construction space, the high weight, and a large amount of needed peripheral devices. To overcome these limitations, compact and light-weight actuator systems can be built by using shape memory alloys (SMAs), which are known for their superior energy density. In this paper, the development of a scalable bi-directional rotational actuator based on SMA wires is presented. The scalability was based on a modular design, which allowed the actuator to be adapted to various application specifications by customizing the rotational angle and the output torque. On the mechanical side, each module enabled a small rotatory motion, which added up to the total angle of the actuator. The SMA wires were arranged in an agonist-antagonist configuration to provide active rotation in both directions. The presented prototype achieved a total rotation of 100°. The modularity of the mechanical concept is also reflected in the electronics, which is discussed in this paper as well. This consideration allows the electronics to be adapted to the mechanics with minimal changes. As a result, a prototype, including the presented mechanical and electronic design, is reported in this study.

INFRA-OBTURATOR TENSION SLING FOR URINARY INCONTINENCE TREATMENT

Stress incontinence occurs due to the inability to control an urge to urinate, which affects the quality of daily life. Although there is an existing therapeutics with polymer mesh tape, it is hard to fix around the urethra to restore the function of the pubourethral ligament. Therefore, in this research, an infra-obturator tension (IOT) sling was introduced to minimize the mobility of the bladder and urethra against intra-abdominal pressure. To verify the IOT performance, two different hypotheses were formulated: The hardness and volume of the IOT support the urethra and help prevent it from deforming by intra-abdominal pressure. The rotatory motion of the IOT can bend the urethra at the contact point and help restore the function of pubourethral ligament to increase vaginal tension. For the first hypothesis, a finite element simulation was conducted using three-dimensional geometrical model obtained by the computed tomography images of patients. For the second hypothesis, surgeons performed an IOT insertion operation and analyzed the sling rotation from the patients’ CT images (mean: 21∘). From the results, the mobility of the urethra was decreased because of IOT insertion. The mobility was also decreased because of the subsequent fibrotic changes from the encapsulation of the IOT.