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To find a novel resin to remove Co(II), the adsorption behaviour of Co(II) from the simulated acid leaching solution was investigated by ion exchange with AG®50W-X4 resin. Parameters such as reaction time, HCl concentration, and resin concentration affected the loading efficiency of Co(II) by AG®50W-X4 resin were tested. The adsorption behaviour of Co(II) strongly depended on HCl and resin concentration while reaction time was little effect on the loading percentage of Co. The loading behaviour of Co(II) into the resin fitted well with the Langmuir adsorption isotherm and the loading capacity for Co(II) was found at 29.8 mg/g. Moderate HCl solution was effective in eluting Co(II) from the loaded AG®50W-X4 resin. The obtained results investigated that AG®50W-X4 resin was a promising resin to absorb Co(II) from the low acid leaching solution of the spent lithium-ion mobile phone batteries. [ABSTRACT FROM AUTHOR]

This review mainly introduces the recycling technology of lithium and iron from spent lithium iron phosphate (LiFePO4) batteries based on hydrometallurgy. Most of the hydrometallurgical processes consist of pretreatment, leaching, and separation of metal ions from the leaching solution. Although pyrometallurgical processes are reasonably straightforward, the problems related to energy consumption and environmental burden should be overcome. The direct regeneration has attracted much attention due to its advantages of the possibility of repairing cathode materials while maintaining the original material structure. In contrast to leaching process of hydrometallurgy, mechanochemistry employs mechanical measures to break chemical bonds in order to extract lithium and iron from spent batteries. [ABSTRACT FROM AUTHOR]

This study incorporates two unique machine learning algorithms, Huber regression and Light Gradient Boosting Machines (LGBM), for estimating ship consumption of fuel. These methods are employed to create forecasting models for ship fuel consumption during journeys, which is especially useful when interacting with non-linear data. The study then analyzes and evaluates the prediction accuracy of these two approaches compared to a baseline model generated using linear regression. The results of the investigation show that both methods establish extremely accurate predictions while handling non-linear data quickly. However, the Huber-based model outperforms the LGBM in terms of prediction accuracy, with an R-squared value of 0.979 versus 0.917 for the LGBM. In addition, the Huber-based model has a diminished prediction error, with an RMSE of 2.278, compared to the LGBM model's RMSE of 4.55. The graphical methods of the violin plot and Taylor's diagram further established the superiority of Huber ML. These findings imply that Huber regression could be a suitable option for estimating in-route ship fuel usage in real time. As a consequence, this study emphasises the potential benefits of machine learning for accurately predicting ship fuel consumption, providing encouraging possibilities to optimise fuel usage while lowering greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

The increasing demand for platinum group metals (PGMs) across various industries indicates the importance of recovering these noble metals from secondary resources. Typically, after pretreatment, PGMs are dissolved using hydrochloric acid solutions containing strong oxidant by virtue of the chemical stability of their anionic chloro-complexes. Several separation techniques, including cementation, precipitation, ion exchange, and solvent extraction, are employed to separate PGMs from leaching solutions. Each method has distinct advantages and limitations concerning efficiency and product purity. Cementation proves effective for concentrating PGMs in solutions containing base metal ions. However, ion exchange and solvent extraction are more commonly used for the separation of PGMs present in hydrochloric acid leaching solutions. Especially, solvent extraction processes employing commercial extractants, ionic liquids, and deep eutectic solvents have been extensively investigated. While deep eutectic solvents show promising as ‘green’ extractants, further research is required to overcome their limitations for industrial applications. A combined process integrating leaching, solvent extraction, and precipitation could offer an efficient solution for recovering high-purity PGMs from the solution containing diverse metal ions. [ABSTRACT FROM AUTHOR]

Piezoelectric thin films have been widely used in electro-acoustic devices including ones measuring Rayleigh wave speed. The main objective of this work is to find an explicit formula of Rayleigh speed taking into account the effect of the thin piezoelectric film. First the problem of Rayleigh surface waves propagating along an orthotropic substrate coated by a thin piezoelectric film is considered using Stroh's formalism approach. Then, the exact secular equation of Rayleigh wave is obtained in implicit form. In case when the thickness of the thin layer is much smaller than the considering wavelength of Rayleigh waves, an asymptotic formula of Rayleigh speed is derived from the asymptotic form of the exact secular equation. The obtained asymptotic formula is simple enough and could be used in practice when Rayleigh speed is measured by using piezoelectric device. Numerical illustrations are carried out to show the validity of the obtained approximate formulas and its potential application in inverse problem. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) and 3D printing (3DP) offer unique opportunities for experiential learning and practical application in engineering education. In developed countries, AM is integrated into engineering education to train mechanical engineers. However, existing research has not investigated the integration of AM and 3DP into higher education in developing countries. Semi-structured interviews were conducted with students and educators from mechanical engineering programmes in Vietnam to examine AM usage in engineering education. Our study revealed that no curricula or policies to integrate AM into classrooms exist in the participating institutions. Engineering schools are attempting to introduce 3DP to students through short courses, but educators have inadequate training. The lack of consistent communication among institutions has hindered the growth of 3DP education. Therefore, to meet the standards of Industry 4.0, it is crucial to have policies and funding in place to promote AM growth among first-year engineering students. [ABSTRACT FROM AUTHOR]

Recovery of nickel and cobalt from laterite ores is important to meet the demand for these metals. In this work, a process was developed for the separation of metal ions from synthetic sulfate leach liquor of laterite ores containing Fe(III), Al(III), Ni(II), Co(II), Ca(II), Mg(II), and Mn(II). First, Fe(III) and Al(III) were removed by precipitation of their hydroxides by adjusting solution pH and then Mn(II) was removed from the filtrate by oxidative precipitation with NaClO. Sequentially, Co(II) and Ni(II) from the filtrate containing Mg(II) and Ca(II) were separated by selective precipitation of CoS and NiS by adding Na2S solution, leaving Ca(II) and Mg(II) in the filtrate. The mixed precipitates of CoS and NiS were completely dissolved by 0.1 M HCl solution containing NaClO. Co(II) can be separated from Ni(II) present in the HCl solution by either oxidative precipitation with NaClO or selective extraction with saponified Cyanex 272. Optimum conditions for these procedures were obtained. Continuous experiments indicated that the purity of Co(II) and Ni(II) solutions was higher than 99%. [ABSTRACT FROM AUTHOR]

Two new vernonioside K (1) and vernonioside L (2) and four known Δ7,9(11) stigmastane-type steroidal saponins—vernonioside B2 (3), vernoniacum B (4), vernonioside B1 (5), and vernoamyoside A (6)—were isolated from the leaves of Vernonia amygdalina. Their structures were determined by comprehensive spectroscopic analysis with one-dimensional nuclear magnetic resonance, two-dimensional nuclear magnetic resonance, and high-resolution mass spectrometry. All isolated compounds (1–6) were evaluated to determine their inhibitory effects on α-glucosidase and xanthine oxidase. Among them, two new compounds 1 and 2 showed significant inhibition of α-glucosidase with IC50 values of 78.56 ± 7.28 and 14.74 ± 1.57 (μM), respectively, comparable with acarbose as a positive control (127.53 ± 1.73 μM); none of these compounds inhibited xanthine oxidase activity. Compounds 1 and 2 are promising candidates for the development of antidiabetic agents from natural sources. [ABSTRACT FROM AUTHOR]

The key focus areas of the internal combustion engine architecture are energy effectiveness and greater thermal efficiency since 1/3 of the produced heat energy vanishes on the way to the atmosphere and the coolant. Experiments have looked into the viability of using tamanu biodiesel in a thermally insulated diesel engine. The engine was first put through its paces on regular diesel fuel as a comparison baseline. After that, the piston, exhaust, intake valve and cylinder head surfaces were coated with partially stabilized zirconia (PSZ) to act as thermal insulation for the engine. The engine coating was developed to improve the efficiency of the engine's use of biodiesel blends by decreasing heat loss through the chamber walls with a thickness of 200 micrometers (µm). In addition, mixes of Tamanu biodiesel with diesel fuel were tested, including B10, B20, B30, and B100, to examine how these mixtures would influence the performance of the ceramic-coated low heat rejection (LHR) engine compared to the performance of the base diesel engine. Additionally, the impacts of different exhaust gas recirculation (EGR) ratios on the operation of biodiesel-powered LHR engines were analyzed. The zirconia insulated LHR engine running on B20 performed the best, with a thermal efficiency of 28.57% and a brake specific energy consumption that was considerably lower than that of the baseline diesel engine. In addition, the LHR engine for B20 reduces carbon monoxide (CO) and smoke emissions by 17% and 21.4%, respectively, compared to the B20- powered base diesel engine, although nitrogen oxide (NOx) emissions slightly increase. However, the addition of 15% EGR to the B20-LHR engine produced a minor increment in hydrocarbon (HC), CO and smoke emissions, corresponding to 19.7% and 25.4%, respectively. By implementing 15% EGR with B20-LHR, the NOx level is reduced by 25.4% due to diluting the air-fuel mixture. The combination of 15% EGR with B20 for a thermal barrier-coated engine offers significant improvement by increasing engine performance and reducing emission characteristics [ABSTRACT FROM AUTHOR]

The study investigates the moderation effect of economic policy uncertainty (EPU) towards the relationship between excess liquidity and bank risk-taking as well as explores its stronger impact in countries severely affected by the 2008 Global Financial Crisis (GFC). Using System Generalized Methods of Moments (SGMM) on an unbalanced dataset for 33 countries from 2000 to 2019, the study finds that an increase in the EPU index attenuates the positive impact of excess liquidity on bank risk-taking. The study also finds that the attenuating effect of EPU on the relationship between excess liquidity and bank risk-taking is stronger in countries that were most severely affected by the GFC. It argues that the mechanisms by which excess liquidity induces risk-taking are disrupted under high EPU. Our study also extends behavioral theories to shed light on how the GFC altered bank risk-taking in the presence of excess liquidity and high EPU. Impact statement: This study examines the influence of economic policy uncertainty (EPU) on the relationship between excess liquidity and bank risk-taking, particularly in countries that were severely impacted by the 2008 Global Financial Crisis (GFC). Utilizing the System Generalized Method of Moments on data from 33 countries, the research indicates that elevated levels of EPU dampen the risk-taking incentives typically associated with excess liquidity. Remarkably, this moderating effect of EPU is more pronounced in nations significantly affected by the GFC, suggesting that historical crises shape current banking behaviourin the face of economic uncertainty. The study enhances the Excess Liquidity Theory by incorporating behaviouralinsights from Prospect Theory, illustrating that economic uncertainty can function as a stabilizing force against liquidity-driven risk. These findings highlight the urgent need for policymakers to customize financial stability measures, particularly in managing liquidity levels and timing policy actions during times of heightened uncertainty. Ultimately, this research offers valuable insights into how regulatory strategies can utilize economic policy uncertainty to promote prudent banking practices, fostering stability in an increasingly volatile global financial environment. [ABSTRACT FROM AUTHOR]

Recently, scientists have developed a variety of approaches and techniques to boost the performance of engines and lower hazardous emissions. One method that has received a lot of interest is the employment of nanoparticles in fuels to address several drawbacks of fuels. Indeed, ceria (CeO2) nanoparticles are a common additive derived from fuel to lower particulate emissions discharged from diesel-powered engines. The preparation techniques and physicochemical features of biodiesel-originated fuels including CeO2 nanoparticles were thoroughly introduced in this review work. Also, the performance, combustion, and emission characteristics and tribological properties of diesel engines running on CeO2-included fuels were completely examined. Furthermore, this paper discussed the noticeable effects of CeO2 nanoparticles on human health and the environment in detail. Generally, adding CeO2 nanoparticles in terms of size ranging from 30–50 ppm into various biodiesel/diesel fuels showed positive impacts in terms of mitigating toxic emissions such as CO, HC, & smoke by the highest of about 94.98%, 91.16%, and 90.3% and improving diesel engine performance with a highest of about 31.25%, though their effects on the ecosystem and human health have been a contentious concern that needs handling in further investigations. The novelty of the current review is to provide comprehensive information on the ppm-specific use of CeO2 nanoparticles as a potential additive to blend with various biodiesel/diesel fuels aiming to improve various engine characteristics, tribological behavior, and environmental impact. [ABSTRACT FROM AUTHOR]

The shells of Tamarindus indica could serve as a primary source of energy generation from biomass. This paper deals with non-isothermal thermogravimetric experiments conducted at heating rates of 5, 10, 15, and 20°C/min with temperatures ranging between 25°C and 700°C to evaluate the kinetic behavior and the thermodynamic properties of Tamarindus indica shell pyrolysis. Three iso-conversational models, Kissinger–Akahira–Sunose (KAS), Starink, and Flynn-Wall-Ozawa (FWO), were used to identify the activation energy (Ea), Enthalpy (ΔH), Entropy (ΔS), and Gibbs free energy (ΔG) of the Tamarindus indica shell biomass. The average activation energy when estimated using KAS, Starink, and FWO models was found to be 209.1, 209.3, and 207.5 kJ/mol with R2 values of 0.91, 0.91, and 0.92, respectively. The average ΔH, ΔS, and ΔG values using the KAS method were found to be 204.4 kJ/mol, 82.2 J/mol K, and 155.2 kJ/mol, respectively. The values of kinetic and thermodynamic triplets indicate that the reaction is non-spontaneous. The findings of this present study reveal that there is an opportunity for Tamarindus indica shells to be used as an alternative biomass fuel due to their eco-friendly nature and ideal properties. [ABSTRACT FROM AUTHOR]

With increasing consumption of lithium-ion batteries (LIBs), recycling of spent LIBs has attracted much attention owing to their potential environmental impacts and metal values. In this work, a hydrometallurgical process for the recovery of metals from metallic alloys containing Co, Ni, Cu, Fe, and Mn generated from the reduction smelting of spent LIBs was developed. From the experimental data, optimum conditions for the complete leaching of the metals from the alloys were obtained as 2.0 mol/L H2SO4 and 10% (v/v) H2O2 solutions at 60°C for 240 min. The separation of metal ions from the sulfate leachate was achieved by using synthesized ionic liquids such as ALi-Cy301 and ALi-SCN and an oxidizing agent like NaClO. First, most of the Cu(II) was selectively extracted over others by 0.2 mol/L ALi-Cy30. Sequentially, Co(II) and Fe(III) from the Cu(II) free raffinate were co-extracted by 0.5 mol/L ALi-SCN and then Co(II) was selectively stripped over Fe(III) by 10% (v/v) NH3 solution. Finally, Mn(II) in the raffinate at pH 3 was precipitated to MnO2 by adding 10% (v/v) NaClO solution, while Ni(II) remained in the filtrate. Mass balance of the whole process indicated that the recovery and purity percentage of metals were higher than 99%. A process is proposed for the effective recovery of valuable metals from the spent LIBs. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are employed in various electronic devices and industries. The recovery of valuable metals from spent LIBs has attracted much interest due to potential environmental issues and economic values. Metallic alloys can be obtained from the UHT process of spent LIBs. In this study, a hydrometallurgical process was developed for the recovery of metal compounds from synthetic metallic alloys containing Co, Ni, and Cu. This process consisted of leaching, solvent extraction, stripping and precipitation. First, the metallic mixtures were completely leached by the mixture of 2.0 moL·L−1 HCl and 10%(v/v) H2O2 solutions at 60°C. Metal ions in the leachate were sequentially separated by solvent extraction with 0.7 moL·L−1 Cyanex301 and 1.0 moL·L−1 Aliquat 336 for Cu(II) and 1.0 moL·L−1 ALi-SCN for Co(II), whereas Ni(II) was remained in the final raffinate. The compounds of Cu(II) and Co(II) were recovered from the respective loaded organics by precipitation stripping method, while Ni(II) compounds were recovered by precipitation from the final raffinate without changing its acidity. Mass balance of the whole process indicated that the recovery percentage of metal compounds such as CuC2O4, CoCO3, and NiC2O4 · 2 H2O was 98.6, 99.4, 99.8% from the leaching solution and the purity of the compounds was higher than 99.9%. A process was proposed for the recovery of pure metal compounds from spent LIBs. The advantages of this process are the possibility that metal compounds with high purity can effectively be synthesized and the aqueous raffinates and the stripped organic solutions after each step can be recycled. [ABSTRACT FROM AUTHOR]

The dissolution behavior of Co, Ni, and Cu and the metallic mixture in acid solutions like HCl, H2SO4, CH3SO3H, and CH3COOH and their mixture with H2O2 was investigated. The effect of parameters such as acid and H2O2 concentration, pulp density, reaction temperature, and time on the dissolution of metals was studied. The CH3SO3H-H2O2 system showed highly selective leaching ability for Co over Ni and Cu from their metallic mixtures at low temperature. Under the optimum condition, Co can be selectively dissolved over Ni and Cu within 30 min at 20°C with 95.0% purity. Ni from the residues was selectively leached over Cu by either H2SO4 solution or the mixture of H2SO4 and H2O2 with above 99.9 and 95.6% purity in either method. A process has been proposed for the separation of the three metals by selective leaching from metallic alloys. This process shows some economic and environmental advantages such as significant decrease in the consumption of acids, reaction temperature, and time. Separation of metals by selective leaching resulted in solutions with high purity and obviation of the subsequent separation steps, which has a favorable effect on the process economics and environment. Thus, the process can be applied to the real operation. [ABSTRACT FROM AUTHOR]

This study presents the Probabilistic Seismic Demand Model (PSDM) and explores optimal intensity measures (IMs) for nuclear power plant (NPP) equipment when subjected to ground motions having high-frequency (HF) and low-frequency (LF) contents. To this end, the PSDM is first constructed in terms of the IM and the corresponding engineering demand parameter, and its outcomes are utilized to select the optimum IMs based on the satisfaction of certain essential properties (i.e., efficiency, practicality, and proficiency). Regarding earthquake excitation, different IMs (i.e., structure-independent and structure-dependent IMs) are studied. The results show that the most appropriate IMs for the seismic performance of the cabinet are velocity spectrum intensity and spectral accelerations for the structure-independent IMs and the structure-dependent IMs, respectively. Moreover, fragility analysis is performed to assess the vulnerability of NPP equipment. The outcomes indicate that the cabinet is highly vulnerable to HF earthquakes as a consequence of response amplification. In addition, the selection of the earthquake IM has an important influence on the collapse capacity of the cabinet, and the fragility curves obtained from structure-dependent IMs are more reliable in comparison to those of structure-independent IMs. [ABSTRACT FROM AUTHOR]

The determination of creep properties of the components operating at high temperatures in thermal power plants is an enormous concern for safe life assessment. In this study, a series of miniature creep and tension tests were carried out with service-exposed (54,750 h and 68,550 h at 650 °C) and virgin Super304H steel materials. The power law creep behaviour, creep rupture life, and tensile properties were compared among the virgin and service-exposed materials. The creep strength of the 54,750-h-serviced material was comparable to that of the virgin material, while it decreased significantly for the 68,550-h-serviced material. The degradation of the properties of the service-exposed material was discussed based on metallurgical analyses and precipitation mechanisms. [ABSTRACT FROM AUTHOR]

This paper proposes a simplified approach for assessing and predicting the seismic risks for electrical cabinets in nuclear power plants (NPPs). The method is a combination of fragility analysis and cumulative absolute velocity (CAV) analysis. First, the high confidence of low probability of failure points from the fragility curves are defined to determine the C A V l i m i t capacity of the cabinet. Then, the potential damage to the electrical cabinet at different locations in Korea is considered via probabilistic seismic maps. Based on the C A V l i m i t capacity, a seismic risk assessment is conducted to observe the operant condition or predict the potential issues of the electrical cabinet under seismic effects. An electrical cabinet is used as a setting for numerical simulation. The finite element model is validated against the experimental results and calibrated by using response surface methodology. Numerical results show that the operant condition of the electrical cabinet can be disturbed by probable earthquakes that have CAV values greater than the C A V l i m i t of 0.27 g‧s. This method is one way that NPP operators can follow to obtain cabinet safety regulations. [ABSTRACT FROM AUTHOR]

In this paper, we assess the reliability of explicit formulas introduced by Pham et al. [Explicit formulas for the reflection and transmission coefficients of one-component waves through a stack of an arbitrary number of layers. Wave Motion. 2015;54:134–144] to compute the propagation of one-component waves through a stack of homogeneous layers, inserted between two half-planes, as a surrogate model of wave propagation in functionally graded materials (FGM). Afterwards, we use the model reliability assessment as diagnostics prior to solving the associated inverse problem. We have used both the Legendre continuous nodal Galerkin method with Gauss–Lobatto quadratures (LCNG) and the Thomson–Haskell (TH) method as reference approaches to approximate the solution of the continuous problem. Consequently, we have compared computationally the output of the surrogate model, the TM method and the LCNG method through sensitivity analysis; and secondly, we have used the surrogate model and the Bayesian inferential framework to estimate the FGM shear modulus given measurements of the amplitude of the reflected wave. We have found that if we know the structure of noise in the data and the signal to noise ratio, then we can reliably infer the FGM shear modulus. [ABSTRACT FROM AUTHOR]

Commercial austenitic stainless steel SUS304H with small amount of vanadium addition was used in this study. Small punch (SP) creep and uniaxial tensile creep tests were conducted at 650, 700, and 750 °C to measure creep lives and the minimum displacement rates or the minimum creep strain rates. The measured parameters were compared between the two test methods, seeking empirical relationships among the parameters using Larson-Miller Parameter and Monkman-Grant relation. Magnitude of the applied stress (MPa) in the uniaxial tensile creep test was approximately equal to the applied load value (N) in the SP creep test at all test temperatures. It was shown that during the creep deformation of the SP creep specimen, crack initiation and accompanying crack growth occur simultaneously. Competing failure mechanisms of creep deformation and crack growth may affect the SP creep life and consequently determine the proportionality function, α, in the relation between the SP load and the tensile creep rupture stress in creep tests. [ABSTRACT FROM AUTHOR]

Early cracking had occurred at a weld joint of a service-exposed P91 steel hot reheat pipe branch. In this study, a series of miniature tensile creep tests were conducted for both the base and weld materials extracted from the retired P91 pipe weld. Tests were conducted at various stress levels at 569 °C to measure the creep properties and investigate the failure mechanisms. Microstructural analyses were also carried out for post-test specimens. The measured creep strengths were represented in terms of the Larson-Miller parameter, and compared to literature data. Most of the data fell within the 95% error band of grade 91 steel. However, the weld metal exhibited higher creep rupture strengths. It showed creep brittle fracture, and base metal showed creep ductile behaviour. The weld metal sometimes had non-uniform microstructures, yielding a seriously tempered zones with minor tempered martensites, thereby causing early creep ductile failure of the weld. [ABSTRACT FROM AUTHOR]

The high-temperature creep fracture behaviour and creep strength of SUS 304H containing a minor addition of V were investigated in this study. A series of small punch (SP) creep and uniaxial creep tests were performed at 700 °C. The load and punch displacement rates obtained from the SP creep tests were used to derive conversion equations to determine the equivalent stress and creep strain rates. A converting equation is suggested in this study so that Norton’s secondary power law creep constants obtained from the SP creep testing can be in agreement with those obtained from the uniaxial tensile creep tests. The creep strength of the modified SUS 304H steel containing V was shown to be superior to that without V based on the current results and other available results for type 304H steel. [ABSTRACT FROM PUBLISHER]

Little information is available about how to build a monitoring system to measure the output of preventive nutrition interventions, such as counselling on infant and young child feeding. This paper describes the Alive & Thrive Vietnam (A&T) project experience in nesting a large-scale project monitoring system into the existing public health information system (e.g. using the system and resources), and in using monitoring data to strengthen service delivery in 15 provinces with A&T franchises. From January 2012 to April 2014, the 780 A&T franchises provided 1,700,000 counselling contacts (~3/4 by commune franchises). In commune franchises in April 2014, 80% of mothers who were pregnant or with children under two years old had been to the counselling service at least one time, and 87% of clients had been to the service earlier. Monitoring data are used to track the progress of the project, make decisions, provide background for a costing study and advocate for the integration of nutrition counselling indicators into the health information system nationwide. With careful attention to the needs of stakeholders at multiple levels, clear data quality assurance measures and strategic feedback mechanisms, it is feasible to monitor the scale-up of nutrition programmes through the existing routine health information system. [ABSTRACT FROM AUTHOR]