Biopolymers are utilized extensively in the medical field. The production of biodegradable bone screws for bone implants utilizing biopolymer materials is one of the advances developments. Polylactic acid (PLA) is a biopolymer frequently employed in medicinal applications. Using 3D printing, this research was done to create a biodegradable bone screw derived from PLA. The 3D printing process was chosen to reduce the cost and duration of bone repair. A nozzle temperature of 210oC and a bed temperature of 60oC are utilized in the production of biodegradable PLA screws. The torque test, fracture analysis, density test, and biodegradation test were utilized to characterize biodegradable bone screws. The results of this study will be compared with commercial biodegradable bone screws (BIOSURE HA). The findings of torsion tests indicate that commercially biodegradable bone screws have superior clamping quality than PLA-based biodegradable bone screws. The degradation rate of commercial biodegradable bone screws is greater than that of PLA-based biodegradable bone screws. In addition, commercial bone screws are denser than PLA-based biodegradable bone screws.

Chitosan has been broadly utilized in bone scaffold production because of its antibacterial qualities, low toxicity, biodegradability, biocompatibility, and ability to aid regeneration processes in wound healing. In this work, chitosan was produced from crab shell waste through demineralization, deproteination, and deacetylation, utilizing HCl 1:7 (v/v), NaOH 3%, 1:10 (v/w), and NaOH 50%. The aim of this study is to examine the deacetylation temperature’s impact towards the crystallinity index, chemical bond, degree of deacetylation, and morphology of chitosan synthesized. The deacetylation procedure was conducted for eight hours at temperatures of 100°C, 120°C, and 140°C. The synthesized chitosan was evaluated by utilizing XRD, FTIR, and SEM methods. According to the findings of this investigation, deacetylation at a temperature of 140 °C produced the highest degree of deacetylation, resulting in the highest quality chitosan. In addition, compared to other obtained chitosans, the shape of this result of synthesis is homogenous. At a deacetylation temperature of 140°C, the amounts of deacetylation degree, and crystallinity index of the chitosan were, in order, 81%, and 44%.

The rotor is one of the vital components of a wind turbine. In the design of the rotor, the expected result is the most optimal power. This purpose study is to optimization of the Horizontal Axis Wind Turbine power of various parameters such as airfoil, angle of attack, and pitch angle. Airfoils (NACA 4412-2412 T.E. mod, NACA 2412-4412 T.E. mod, NACA 4412-2412 L.E. mod, NACA 2412-4412 L.E. mod), angle of attack (0, 2, 4, 6), and pitch angle (0, 1, 2, 3) are the parameter variations used. The simulation method uses BEM (Blade Element Momentum), and the Taguchi for optimization is based on the L16 orthogonal array matrix. The ANOVA has to determine the contribution of each parameter to the HAWT power generated. Simulation and optimization results show that the most optimal parameter was a NACA airfoil 4412-2412 L.E mod, at 0˚ angle of attack and 0˚ pitch angle, with the resulting power reaching 1015780 Watt. The ANOVA analysis shows the airfoil parameter has the greatest contribution to the rotor power of the HAWT compared to the angle of attack and pitch angle.

Clay 3D printing is an emerging field within additive manufacturing that presents significant opportunities for both structural and artistic applications. Driven by the increasing interest in this technology, there is a growing demand for optimized printing protocols tailored to clay, a readily available and versatile material. This study investigates the optimal processing parameters for kaolin clay composites and assesses the influence of clay-to-water ratios on the physical and mechanical properties of printed specimens. Experimental results demonstrate that higher clay content enhances the dimensional stability and structural integrity of printed components. The optimal formulation was determined to be 60% clay and 40% water, which produced the highest mechanical performance: the flexural strength of sintered specimens reached 1.3125 MPa and the compressive strength attained a maximum of 6.14 MPa. Shrinkage analysis indicated that specimens with greater water content experienced increased volumetric shrinkage, with reductions of up to 10% in linear dimensions and 14% in mass during drying and sintering. These findings highlight the critical relationship between material composition and final part performance in clay 3D printing and provide guidance for optimizing material formulations to enhance the mechanical robustness of printed clay composite structures for diverse applications.

Aliran udara laminar memberikan dampak positif bagi benda yang bergerak diudara jika dibandingkan dengan aliran tubulansi. Secara teori, jenis aliran laminar dan turbulansi dapat diketahui dari nilai Reynold number, namun tidak bisa dilihat secara visual tanpa ada alat khusus yang menggunakan asap atau kabut. Wind smoke tunnel merupakan alat yang dapat digunakan untuk mensimulasikan dan memperlihatkan aliran udara serta benda yang bergerak didalam aliran udara. Pentingnya visualisasi aliran udara adalah untuk melihat efek dari berbagai bentuk benda terhadap sifat aerodinamis. Visualisasi aliran udara dapat memberikan gambaran aliran udara yang melewati benda atau obyek tanpa menggunakan perhitungan yang komplek. Benda yang digunakan dapat berupa benda asli atau benda dalam bentuk model yang diatur skala perbandingannya. Wind tunnel dibuat dengan panjang 2 m dengan dimensi seksi uji adalah 50 cm x 30 cm x 20 cmm. Dengan kondisi batas tersebut selanjutnya akan dihitung dimensi untuk construction dan diffuser wind tunnel. Selanjutnya adalah membuat smoke generator yang akan digunakan untuk memperlihatkan aliran udara disekitar benda uji. Smoke generator dibuat dengan mekanisme pembakaran fuel yang kemudian disambungkan pada pipa yang terpasang pada wind tunnel. Benda uji yang telah dibuat kemudian dipasang pada test section kemudian dijalankan fan pada wind tunnel sehingga menghisap udara untuk melewati benda uji dan akan memperlihatkan pola aliran disekitar benda uji.

The process of drying briquettes in an oven is very costly due to the amount of fuel, labor, and drying time required. Furthermore, inadequate air circulation also results in an uneven and ineffective drying process for briquettes. The performance of the briquette drying oven can be improved by changing the geometry of the perforated plate in the oven to optimize the air distribution. This research process was conducted through Computational Fluid Dynamics (CFD) simulations using Ansys Fluid Flow (Fluent) software by testing three different perforated plate geometries in the oven to determine their effect on the air distribution that occurred in the oven. The research findings indicate that the temperature, velocity, pressure, and airflow pattern of the air are all considerably impacted by the incorporation of perforated plates into the first, second, and third geometries of the oven. When compared to the original geometry, the average air temperature in ovens using the first, second, and third geometries increased by 6.86%, 7.38%, and 9.15%, respectively. Average air velocity increased by 226.04%, 235.77%, and 431.60% in ovens with the first, second, and third geometries. However, the air pressure in ovens with the first, second, and third geometries decreased by 11.05%, 8.62%, and 10.66%. The use of perforated plates on the right, back, and left sides in an oven with the third geometry is the best geometry produced in this research. This happens because this oven produces the most even airflow pattern in the oven compared to other geometries. In addition, the oven with the third geometry has the highest average temperature and average air velocity, with a lower average air pressure compared to the other geometries. Consequently, drying is more effective and takes less time.