Beach protection is vital to reduce the damage to shorelines and coastal areas; one of the artificial protections that can be utilized is the tetrapod. However, much damage occurred when using a traditional tetrapod due to the lack of stability coefficient (KD). Therefore, this research aims to increase the stability coefficient by providing minor modifications to the cape of the tetrapod, such as round-caped or cube-caped. The modification seeks to hold the drag force from the wave and offer a good interlocking in between the tetrapod. This research applied physical model test research using a breakwater model made from the proposed innovative tetrapod with numerous variations in dimensions and layers simulated with several scenarios. The analysis was carried out by graphing the relationship between the parameters of the measurement results and the relationship between dimensionless parameters, such as wave steepness H/gT2, and other essential parameters, such as the KD stability number and the level of damage in %. The result shows that the modified and innovative tetrapod has a more excellent KD value than the conventional tetrapod. In addition, the innovative tetrapod with the cube-shaped has a recommended KD value greater than the round shape. This means that for the modified tetrapod structure and the same level of security, the required weight of the tetrapod with the cube cap will be lighter than the tetrapod with the round cap. These findings have significant practical implications for coastal protection and engineering, potentially leading to more efficient and cost-effective solutions.
This study examines how economic freedom and competition affect bank stability. We use data from 70 ASEAN-4 banks from 2007 to 2019 using the system generalized technique of moments. Results corroborate competition-fragility hypothesis. Market strength (or less competition) can boost bank stability. However, in the ASEAN-4 area, competition and bank stability have a non-linear relationship, suggesting that bank stability may decline after market strength exceeds a threshold. Financial and economic freedom also boosts bank stability. This implies banks in free financial and economic contexts are more stable. Banks with more market dominance in nations with more economic or financial autonomy may also be more unstable. The findings suggest that authorities should allow some competition and economic flexibility to keep banks stable. The study examined ASEAN-4 economic freedom’s effects empirically for the first time. It illuminates competitiveness and bank stability.
In this study, the effect of roasting and boiling on the yield and oxidative stability of soya bean oil was investigated. The oil was soxhlet extracted and the oxidative stability was determined by the free fatty acid value, acid value and peroxide value. The results showed that the oil yield, free fatty acid value, acid value and peroxide value were significantly affected by roasting, boiling, and the thermal treatment time. The percentage oil yield in the control oil sample was 18.51%, which increased to 20.24% and 20.73% after boiling and roasting respectively, at 40mins. The corresponding free fatty acid and the peroxide value of the control oil sample were 0.14% and 2.04 meqO2/kg, which increased to 0.82% and 6.60 meqO2/kg by roasting, and 0.47% and 5.62 meqO2/kg by boiling respectively. Thus the oil yield, free fatty acid value, peroxide value, and acid value increased with increasing roasting and boiling time.
The results indicate that roasting provides a higher oil yield than boiling, but boiled oil has higher oxidative stability than roasted oil.
Synthetic membranes play a crucial role in a wide range of separation processes, including dialysis, electrodialysis, ultrafiltration, and pervaporation, with growing interest in synthetic emulsion membranes due to their precision, versatility, and ion exchange capabilities. These membranes enable tailored solutions for specific applications, such as water and gas separation, wastewater treatment, and chemical purification, by leveraging their multi-layered structures and customizable properties. Emulsion membrane technology, particularly in pressure-driven methods like reverse osmosis (RO) and nanofiltration (NF), has shown great potential in overcoming traditional challenges, such as fouling and energy inefficiency, by improving filtration efficiency and selectivity. This review explores the latest advancements in emulsion membrane development, their adaptability to various industrial needs, and their contribution to addressing long-standing limitations in membrane separation technologies. The findings underscore the promise of emulsion membranes in advancing industrial processes and highlight their potential for broader applications in water treatment, environmental management, and other key sectors.
Polymer waste drilling fluid has extremely high stability, and it is difficult to separate solid from liquid, which has become a key bottleneck problem restricting its resource recycling. This study aims to reveal the stability mechanism of polymer waste drilling fluid and explore the destabilization effect and mechanism of ultrasonic waste drilling fluid. Surface analysis techniques such as X-ray energy spectrum and infrared spectrum were used in combination with colloidal chemical methods to study the spatial molecular structure, stability mechanism, and ultrasonic destabilization mechanism of drilling fluid. The results show that the particles in the drilling fluid exist in two forms: uncoated particles and particles coated by polymers, forming a high molecular stable particle system. Among them, rock particles not coated by polymer follow the vacancy stability and Derjaguin-Landau-Verwey-Overbeek (DLVO) stability mechanism, and the weighting material coated by the polymer surface follows the space stability and DLVO stability mechanism. The results of ultrasonic destabilization experiments show that after ultrasonic treatment at 1000 W power for 5 min, coupled with the addition of 0.02% cationic polyacrylamide, the dehydration rate is as high as 81.0%, and the moisture content of the mud cake is as low as 29.3%, achieving an excellent solid-liquid separation effect. Ultrasound destabilizes polymer waste drilling fluid by destroying the long-chain structure of the polymer. This study provides theoretical support and research direction for the research and development of polymer waste drilling fluid destabilization technology.
In the present work, a series of butyl methacrylate/1-hexene copolymers were synthesized, and their efficiency as viscosity index improvers, pour point depressants, and shear stabilizers of lube oil was investigated. The effect of 1-hexene molar ratio, type, and concentration of Lewis acids on the incorporation of 1-hexene into the copolymer backbone was investigated. The successful synthesis of the copolymers was confirmed through FTIR and 1H NMR spectroscopy. Results obtained from quantitative 1H NMR and GPC revealed that an increase in the molar ratio of 1-hexene to butyl methacrylate, along with concentration of Lewis acids led to an increase in 1-hexene incorporation and a reduction in Mn and Ð. Similar trends were observed when the Lewis acid changed from AlCl3 to organometallic acids. The maximum 1-hexene incorporation (26.4%) was achieved for sample BHY3, with a [1-hexene/BMA] ratio of 4 mol% and a [Yb(OTf)3/BMA] ratio of 2.5 mol%. Evaluation of the synthesized copolymers as lube oil additives demonstrated that the viscosity index was more significantly influenced by samples with higher molecular weight. Sample BHA13 represents maximum VI of 137. The copolymer containing Yb(OTf)3 as a catalyst exhibited superior efficiency as a pour point depressant. Furthermore, sample BHY3 showed the lowest shear stability index (6.4).
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