International Journal of Pioneering Technology and Engineering

Enhanced out-of-plane loading performance of multi-scale glass/epoxy composites doped with HNTs

Mahmut Özer — 2023-06-04

Glass fiber reinforced composites have attracted great, widely used specific industrial areas such as defense, aerospace, etc. However, composite plates are defenseless to damage accumulation such as matrix cracks, fiber delamination, and delamination, which limits the application of glass composites in specific industrial areas at limited strength levels. Therefore, analysis of the behavior of composites under the out-of-plane loads is essential to optimize such material. This study examines the out-of-plane loading performance of multi-scale glass/epoxy composite laminate. To improve the load-carrying performance in the direction of out-of-plane, the halloysite nanotube (HNT) particle reinforcement was introduced to the epoxy matrix. The three-point bending tests were conducted to attain the out-of-plane load-carrying performance. The findings show that the flexural strength increases by almost 20% for the HNT-modified glass/epoxy composite compared to the unmodified counterpart; meanwhile, the toughness is effectively improved with the HNT addition. Moreover, the damage process of specimens in three-point bending tests was detected by microscopic examination.

Analysis of Working Postures in Rubber Manufacturing Industry by using OWAS and RULA Methods

Merve Yılmaz — 2023-06-04

The basic conditions of working in a healthy and safe workplace are to design the job in accordance with the anthropometric measurements, body strength and personal characteristics of the person, to ensure that the materials, machinery and equipment used in the working process are suitable for the employee's capacity, and to provide an environment that will produce positive psycho-social results. Correct analysis methods should be used and evaluated in order to meet this basic requirement. Identifying the negative effects of working postures, taking corrective measures and improving them is a critical step of an efficient working environment. Working postures that are not properly analyzed cause strain on workers and even discomfort. It provides important contributions in the field of analyzing and improving working postures with scientific methods, controlling work performance and reducing musculoskeletal disorders (MSDs). OWAS (Ovako Working Posture Analyzing System) and RULA (Rapid Upper Limb Assessment) are successfully applied in various fields in the analysis of working postures. In this study, it was aimed to determine the MSDs risk levels of the workers working in the rubber industry by OWAS and RULA methods and measures were proposed for these risks. While OWAS analysis was obtained by using expert opinions in the study, CATIAV5R20 program was used for RULA analysis. The study includes the examination of 5 different postures in total. In the OWAS and RULA results of the study, it was seen that the most risky postures are attach the rubber hose to the cores and to place the rubber hoses attached to the cores in the autoclave. The results of the analysis showed that the RULA method is more suitable and reliable than the OWAS method for the analysis of the tasks in the vulcanization process workstations.

The evolutionary relationships of microRNAs in the regulation of glucose and lipid metabolism in human and animals

Osman Sabri Kilic — 2023-06-04

microRNA (miRNA) is a non-coding RNA type, regulating gene expressions at a post-transcriptional level. Changes in miRNA expressions can cause problems such as lipid metabolism disorder, cardiovascular disease, growth retardation, low birth weight and insulin resistance, etc., in human and animals. In this study, we investigated the evolutionary relationships of 14 miRNAs including hsa-miR27a-5p, hsa-miR149-3p, hsa-miR374c-5p, mmu-miR-678, mmu-miR-698-5p, hsa-miR-199a-3p, hsa-miR122-3p, hsa-miR342-3p, mmu-miR201-5p, hsa-miR429, hsa-miR370-3p, hsa-miR130a-5p, hsa-miR330-3p and hsa-miR770-5p related to different metabolic pathways including cardiovascular diseases and lipid metabolism. For this purpose, miRNAs were retrieved from miRBase database. After, Clustal Omega analyses were performed for alignment, and a phylogenetic tree was constructed via MEGA 11. Phylogenetic tree indicated that 14 miRNA sequences were clustered into four groups. One group consisted of mmu-miR-678, and the other 13 sequences were separated into three groups, revealing a close relationship among miRNAs. Findings from different studies provide a new perspective for potential miRNA-based biomarkers to detect lipid metabolism disorders, cardiovascular diseases as well as related disorders.

On the Measurement of Nakazima Testing Based Out-of-Plane Forming Limit Curves using 2D Digital Image Correlation

Akshat Agha — 2023-06-04

The strain compensation method for measuring in-plane forming limit curves (FLCs) using 2D digital image correlation developed previously [A method of measuring in-plane forming limit curves using 2D Digital Image Correlation, SAE Int. J. Mater. Manf., 2023] was modified and extended to more versatile and popular out-of-plane FLCs. The current study introduces a straightforward strain compensation technique for measuring Nakazima testing based out-of-plane FLCs utilizing an affordable single-camera (2D) DIC system. In this study, forming tests are performed on two automotive-grade sheet metal alloys: DP980 steel and a 6xxx series aluminum alloy using the Nakazima test method. The experiments are conducted on a customized setup that allows for simultaneous optical strain measurements using both a stereo DIC and a 2D DIC system. The FLCs are obtained by applying a temporal FLC computation approach to the two measurement sets. The results show that 2D DIC FLC points match those obtained by stereo DIC for both the materials after applying the proposed strain correction method.

Base Bleed Flow Control Tool for Circular Cylinders with three Side-By-Side Arrangements in Shallow Water

Mustafa Atakan Akar — 2023-06-04

In this study, Particulate Image Velocimetry (PIV) was utilized to determine the flow characteristics of three side-by-side circular cylinders with a base bleed. The height of the water was set as hW=20 mm which has characteristics of shallow water and flow images were captured from an elevation of hL/hW= 0.5 (mid-plane of water height). The freestream velocity of water and circular cylinder diameters were chosen as U∞=0.125 m/sec and D=40 mm, respectively which are the corresponding Reynolds number of ReD=5000. Three different gap/diameter ratios between the cylinders were tested as G/D=1.0, 1.25, and 1.5 throughout the experiments. As a passive flow control technique, base bleed slots located through the cylinders were used with the dimensionless width ratio of B/D= 0.05 to 0.25 with 0.05 increment. As a result of the study, the base bleed was found out an effective way to control unsteady wake. Besides, whereas the increasing height of VSP results in further decrement turbulence statistics, Increasing the width of base bleed leads to a reduction of maximum Reynolds shear stress concentration. Nevertheless, jet deflection flow cannot be avoided for the G/D=1.25 while, flow deflection is avoided with all base bleed case the gap ratio increases to G/D=1.5. The wake size of each cylinder is almost the same for G/D=1.5.