Journal articles

Influence of specimen size on the small strain dynamic properties and strength of compacted Bentonil-WRK bentonite for nuclear waste repository

2026-01-23T03:15:30Z

Influence of specimen size on the small strain dynamic properties and strength of compacted Bentonil-WRK bentonite for nuclear waste repository Balagosa, Jebie; Navea, Ivan Jeff; Lee, Minhyeong; Yoon, Seok; Choo, Yun Wook This study examines the small-strain dynamic properties and strength of highly compacted Bentonil-WRK bentonite, a candidate buffer material for engineered barrier system (EBS) in South Korea. Free-free resonant column (FFRC) and unconfined compressive tests (UCT) were performed on specimens with varying diameter sizes (Ø), dry density (ρ_d), and degree of saturation (S_r). FFRC determined shear, unconstrained and constrained compressive wave velocities (V_s, V_c, and V_p, respectively), small-strain moduli, material damping in shear (D_smin) and longitudinal (D_ucmin). The influence of increasing Ø, ρ_d, and S_r were investigated by utilizing seismic waves to (1) determine the dynamic stiffness, (2) characterize material damping, (3) permit direct calculation of dynamic Poisson's ratio (v), and (4) develop moduli and strength correlations. An inverse size effect was observed, wherein increasing Ø reduced velocities, moduli, damping, v, and strength. Conversely, increasing ρ_d enhanced mechanical properties, with maximum values at around 70 % S_r. Plasticity index and mineral constituents contributed to the observed nonlinearity in Dsmin and Ducmin. Although Ø and Sr partially contributed, mechanical correlations were primarily influenced by ρ_d under unconfined conditions. Hence, the proposed wave-based equations enable practical assessment of bentonite buffer blocks after production and prior to installation in nuclear waste repositories. Journal article

Automated identification and security system for ECE laboratory

2023-03-28T09:00:20Z

Automated identification and security system for ECE laboratory Cajita, Modesto Trexine; Alguidano, Ramon A. Jr.; Soriano, Melanie; Sarmiento, Julius The population of ECE students of Central Philippine University (CPU) is increasing and the staff of ECE Lab has the hard time monitoring students who want to access the Lab. Laboratory teachers usually require the laboratory assistants to record the time duration the student uses the laboratory. Manual log-in and logout is done for this purpose and it cannot be avoided that sometimes this system gives erroneous results and take up considerable time. This paper describes our project under Engr. Cirilo C. Calibjo which is a solution to problems inherent to manual log-in and log-out procedures. The objective of the project is to design an automated identification and security system using the M68HC11 microcomputer unit (MCU) of Motorola to remedy the problem. We developed a system which requires two sets of numbers to gain access in the lab., a prototype was made to test the functionality of our design. Although actual field implementation and testing was not possible, the prototype results were encouraging. Journal article

Synthesis, scale inhibition performance evaluation and mechanism study of 3-amino-1-propane sulfonic acid modified polyaspartic acid copolymer

2023-03-06T01:34:20Z

Synthesis, scale inhibition performance evaluation and mechanism study of 3-amino-1-propane sulfonic acid modified polyaspartic acid copolymer Zhang, Xiao-Juan; Zhao, Xiaowei; Zhang, Menglong; Jaspe, Christsam Joy S.; Cheng, Yamin; Cao, Zhong-Yan; Wu, Yufeng; Xu, Ying A water-soluble polyaspartic acid derivative scale inhibitor (PASP-Ho) was synthesized from 3-amino-1-propanesulfonic acid (Ho) and polysuccinimide (PSI) as raw materials. The structure of PASP-Ho was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (¹H NMR). The scale inhibition performance of PASP and PASP-Ho was determined by static scale inhibition method. The results show that compared with PASP the scale inhibition performance of PASP-Ho has been greatly improved, especially at low concentrations. The scale inhibition performance of PASP-Ho reaches 100% against CaSO₄, which is 54% higher than that of PASP at the dose of 4 mg·L⁻¹; the scale inhibition performance of PASP-Ho against CaCO₃ is improved by 42% at the dose of 5 mg·L⁻¹. The crystal surface morphology and crystal structure were characterized by field emission scanning electron microscopy (SEM), X-ray diffraction techniques (XRD), and X-ray photoelectron spectroscopy (XPS), indicating that the addition of PASP-Ho enhanced the chelation and dispersion effect, destroying the surface morphology of the crystal. The scale inhibition mechanism was further deduced by conductivity measurement and density functional theory (DFT). The addition of PASP-Ho can increase the surface energy of CaSO₄ and CaCO₃ scales, reduce the nucleation rate of crystals and inhibit the formation of scales. The scale inhibition mechanism of PASP-Ho is a combination of chelation, dispersion, threshold effect and lattice distortion, but only a little lattice distortion is exhibited for CaSO₄ scale. Journal article

Scale inhibitors for industrial circulating water systems: A review

2023-03-06T00:46:32Z

Scale inhibitors for industrial circulating water systems: A review Guo, Xinyu; Jaspe, Christsam Joy S.; Cheng, Yamin; Zhao, Xiaowei; Liu, Zongyang; Xu, Ying Presence and deposition of sparingly soluble salts, known as scale, has been one of utmost damaging problems of circulating water. In industry, the scaling phenomenon may cause technical problems such as reduction of heat transfer efficiency in cooling systems and obstruction of pipes. Therefore, adding scale inhibitors that exhibit desired efficiencies to control scale is so important to mitigate adverse effect in water circulation systems because of their high tolerance for cations, such as Ca²⁺, Mg²⁺, and their ability to efficiently dissolve the unstable polymorphs of inorganic salts at the early stages of crystallization, thus impairing scaling. This paper reviews the research progress and state-of-the-art developments of scale inhibitors, including natural scale inhibitors and synthetic scale inhibitors. Natural scale inhibitors, including natural organic and plant extract scale inhibitors, are non-toxic, inexpensive, widely used, biodegradable and in line with the characteristics of green chemistry. Synthetic scale inhibitors mainly composed of phosphorous, polycarboxylic acid and polyaspartic acid are widely used due to their excellent performance. Detailed comparison between natural scale inhibitors and synthetic additives alongside future directions towards antiscalant are also discussed. The former are less water-soluble, while the latter require a large dosage, which causes a great burden to the environment. In particular, the need for developing green, efficient, easy preparation, and pollution-free scale inhibitors, studying the interactions between scale inhibitors and metal ions is stressed. It is expected that this paper could offer an insight in deeper understanding the scale inhibitors in industry and provide some clues for exploring more advanced scale inhibitors technologies. Journal article