Portugaliae
Electrochimica Acta

This work focused on developing prediction models using ANN, in order to forecast the long-term performance of reinforcements in concrete slabs containing pure Mg anodes, and subjected to Cl- ingress. The experimental set-up consisted of two built RCC slabs with 1000 x 1000 x 100 mm. Slab #1 was cast with 3.5% NaCl by cement weight. Slab #2 was cast without NaCl. Considered input parameters were the distance of the anode from the point under consideration in x and y-axes, T, RH and concrete age in days. HCP values concerning SCE were considered output. Experimental values consisted of 80 HCP per slab/day. These were collected for 270 days, in order to generate the prediction model. The learning heuristic used LM supervised learning in feed-forward. A two-layer feed-forward network, with ten hidden sigmoid neurons and trained linear output neurons, was employed. The network architecture [5-10-1] and ten neurons in the hidden layer were used for all prediction models. The accuracy level of results obtained with LM was above 97%. Keywords: ANN model; Cl-induced corrosion; HCP; SA from Mg.

Patients with fractures require internal fixations, since treatment options are limited to metallic implants and autologous bone grafts. These limitations include chances of infection transference, quantity restrictions and the need for additional surgery. Bone tissue engineering seeks to address these limitations through the development of biocompatible bone scaffolds. This study fabricated a PLA based scaffold that sought to address some of the challenges associated with currently available treatment options. The methodology involved acquiring raw eggshells, which were rinsed with water and calcined with concentrated H3PO4. Hitherto, HAp powder was extracted from eggshells, and its presence was confirmed using color test. PLA (60,000 molecular weight) was procured from Sigma Aldrich, which was used with HAp powder, to form the composite, employing sol gel technique. SEM morphology established PLA, which has polymeric binding properties, as the 3D scaffold with the highest Ct (PLA/HAp (45/55 wt.%). It had a more consistent crystal and pore formation and weaker grain boundaries. FTIR analysis showed PLA characterizing peaks, and that functional groups present in 3D scaffold are not toxic to the body. X-RD spectra confirmed PLA and HAp presence in 3D scaffolds. However, peaks intensities decreased with lower Ct of HAp, and those of PLA increased in the 3D scaffold. This indicates that PLA and HAp particles have semi-crystalline and crystalline structures, respectively. Thus, 3D scaffolds can be tailored for many biomedical applications. Keywords: bone fillers; characterizations; HAp; PLA; scaffold.

Different Ct of KBE from its leaves were used to study its effect on MS corrosion resistance. Electrochemical methods such as PDP, EIS and WL tests were herein used. Experimental results showed that, with higher Ct of KB, its IE(%) increased. The highest corrosion IE(%) of 98.41, at 1600 ppm KBE in a 0.5 M H2SO4 solution, was obtained. The inhibitor’s adsorption onto the MS surface was excellent, since it created a monolayer. KBE´s adsorption mechanism obeyed Langmuir’s isotherm. SEM analysis established the development of a protective layer on the MS surface. Keywords: CI; EIS; LPR; PDP;SEM; WL.

employing Lingane’s equation in a simple and extended form. Ionic strength was kept constant by using NaClO4 and KNO3 as SE. All measurements were performed at a constant T of 298±1 K. The approximation of all possible Lingane’s equations was established. According to obtained results, it was concluded that the equation should be used in its extended form. In KNO3 and in NaClO4, q was found to be 5 and 6, and  logarithms were found to be 21.20 and 24.47, respectively. Spectrophotometric study was also performed to determine stoichiometry and  of Cd(II)/Na-DDTC complex in the same SE. Data indicated that Na-DDTC should be combined with Cd in molar ratios of 1:5 (ML5), in KNO3, and of 1:6 (ML6), in NaClO4.  logarithms were calculated to be 22.26 and 23.94, in KNO3 and NaClO4, respectively. IE(%) of Na-DDTC as an ecofriendly CI for CS in 0.5 M H2SO4 medium was also investigated using WL measurements. Experimental results showed that IE(%) increased with higher inhibitor’s Ct. The inhibitor’s adsorption onto the CS surface obeyed Langmuir’s isotherm, and it proceeded by both physisorption and chemisorption modes. ΔGads was determined. The effect of Cd2+ addition, which formed a complex with Na-DDTC, was also studied. Keywords: B; CI; DPV; Job’s method; Na-DDTC.

In the present study, a thin film of NixSy was deposited on an ITO GP by SILAR method. This film was characterized by UV-vis reflectance and FTIR spectroscopy. UV-vis reflectance revealed that Eg from NixSy was 1.55 eV. After coating, ITO GP Eg decreased from 1.88 to 1.55 eV. This indicates that the film functioned as a semi conductor. UV-vis absorbance showed that the film absorbance occurred at 322.00, 388.80 and 396.25 nm, with peak intensity of 1.229, 0.934 and 0.916 AU, respectively. FTIR spectra confirmed NixSy formation on ITO GP by SILAR technique. Thus, it was encouraging to note that NixSy was successfully prepared by this method. Electrochemical studies, such as polarization technique and AC impedance spectra revealed that current flowing through ITO GP increased after NixSy coating by SILAR method. These findings may be useful for solar panel systems used in marine environments. Keywords: Eg; electrochemical studies; ITO GP; NixSy; SILAR method; thin film.

Bd was produced by transesterification of refined NSO with MeOH and CaO catalyst using batch mode. Physicochemical properties of NSO and Bd as an alternative diesel fuel were characterized using ASTM fuel test standards. The FA composition and functional groups of Bd were investigated using GC-MS and FT-IR, respectively. The effect of basic parameters such as reaction catalyst Ct, MeOH/oil molar ratio, reaction T and time, and SS were determined using batch mode. These process parameters were optimized using RSM and ANOVA. The importance of various process parameters and their combined effects on transesterification performance was determined through CCD. Statistical analyzes of the data led to the development of a second-order quadratic polynomial regression model that established the relationship between Bd yield and process variables. The model was able to adequately predict Bd yield with R2 value of 0.9942. The obtained results were in good agreement with published data for Bd from other vegetable oils, as well as with various international standards for this product. An optimal yield of 94% was achieved under optimal conditions of catalyst Ct (4 wt%), MeOH/oil molar ratio of 8:1, T of 55 °C, time of 60 min and SS of 400 rpm. The results show that Bd produced using alcohol in the transesterification process improved CP and CFPP properties. Keywords: ANOVA; Bd; NSO; oil transesterification; optimization; RSM.

Poultry meat is a high-protein source that is consumed all over the world. This source is tainted not only by viruses but also by environmental contaminants, including HM. This study aimed to detect HM in the tissues (liver, gizzard, muscles, heart and kidney) of BC and DC in Quetta city, Balochistan, Pakistan for the first time, using AAF. Samples were collected from different regions of the district, and prepared for analysis. The measured Ct (mg/L) of detected HM like Pb (0.30-0.83), Co (0.18-0.35), Mn (0.10-0.21), Fe (0.32-12.70) and Cu (3.79-4.51) varied across different organs in analyzed BC and DC samples. Cu, Mn, Co and Fe content was within the range of acceptable values established by WHO and ANZFA. However, Ct of Pb for BC and DC exceeded WHO’s (0.2 mg/L) and EU’s (0.1 mg/L) permissible limits. Therefore, more in depth research studies on poultry feed should be carried out, for its improvement and safety. Keywords: AAS; BC; DC; HM.

NH has the ability to control corrosion of various metals and alloys such as Al, CS, Cu, Cu Sn, MS, Sn and SS. It behaves as a CI in acidic, basic or neutral media. In the several studies herein reviewed, various techniques like WL, and electrochemical methods such as PDP and EIS, have been used to evaluate NH corrosion IE (%). Protective films have been analyzed by FT-IR, UV-vis spectroscopy, GC-MS, SEM and EDX methods. NH adsorption onto the metals and alloys surface has obeyed Langmuir’s isotherm. PDP studies have revealed that NH may function as an anodic, cathodic or mixed type of CI, depending on the metal nature and on the corrosive environment. Keywords: CI; EDX; EIS; FT-IR; GC-MS; NH; PDP; SEM; WL.

Modern predictive modeling techniques, such as regression, NN and decision trees can be used to build better and more useful models. JMP 17.2.0 was used in this study to develop a fitting model for microbial growth observed data from chicken manure and banana peels labelled as Sample A, and a single chicken manure substrate, identified as Sample B. Statistical metrics, including COD (R2), RASE, MAD, negative log-likelihood and SSE were used to determine best predictions for Ct (X) from biomass of 22 and 24 samples (A and B) on SC (S) and SGR of microorganisms (μ). Along with estimated Monod parameters, TanH function SAS codes for 3 declared hidden layers, also demonstrated by surface plots, portrayed Sample B predicted model as the best one, even though the 2 samples datasets R2 values for training (A: 0.9887916 and B: 1.0000) and validation (A: 0.9787637 and B: 0.9999999) pointed to a good fit. According to findings, optimal conditions for datasets were: A- biomass = 899868717 mg/L and SC = 4.62 x 109 mg/L, correspondent to high µ (0.010201 h-1); and B- biomass = 15351147 mg/L and SC = 9.2322 x 109 mg/L, consistent with µ of 0.007316 h-1. RMSE, which is the standard method of choice for evaluating the accuracy of predictive models, including those based on NN, should be activated in future studies. This research is both timely and relevant in the pursuit of sustainable waste management and renewable energy generation. Keywords: ANN; JMP; Monod; SAS code; SGR; SC; TanH function.

The present study conducted investigations on Bd generated from palm WCO. In TE reaction, alkaline bases for catalysts are often employed. However, since WCO contains high Ct of free fatty acids, its direct use is not feasible, due to layer separation and saponification issues. A two-step process of esterification and TE was herein carried out. GC made from biomass was used. With lower Ct of WCO, maximum Bd yield was achieved using 5 wt.% from GC, CH₃OH:oil ratio of 12:1, reaction time of 70 min, T of 150 ºC and stirring speed of 600 rpm. TE’s second stage employed NaOH, T of 70 ºC and Ct of 1.0 wt.%, for 70 min. Final yield was 95.65 wt.%. Most important variables determining economic feasibility were plant capacity and pricing of feedstock oil and Bd. Keywords: Bd; catalyst; esterification; GC; TE; WCO.

subsequent calcination (HNS/MWCNT). Then, they were employed as an electrochemical sensor for SFA. The synthesized CuO/ZnO was characterized using various techniques, including TEM, SEM, FT-IR, EDX, DPV and CV. Electrochemical studies revealed that HNS from CuO/ZnO/MWCNT modified electrode exhibited high A, more reactive sites and excellent electrochemical catalytic activity towards SFA oxidation, compared to GCE. The pH, modifier amount, SR and analyte Ct effects on oxidation ip were investigated, to optimize experimental conditions. LoD of 0.089 µM and linear calibration range from 0.1 to 1000 µM were obtained for SFA determination on HNS from CuO/ZnO/MWCNT/GCE. The modified electrode was successfully applied for SFA determination in WW, pharmaceutical and biological samples. Keywords: complex-directed hybridization; CV; DPV; HNS; MWCNT; SFA; ZnO/CuO.

This research was conducted through color coronal spectral analysis (Ignatov, 2007). This method was employed under laboratory conditions, utilizing corona glow emitted by liquids and biological objects. The studies were performed with a high voltage of 12 kV and a high frequency of 15 kHz. In 1995, Antonov devised an apparatus with a transparent electrode for research with black-white photographic films. He named this method SHFD. In 2007, the device was improved by Ignatov and Stoyanov, for color Kodak films. Under specific electrical conditions, it is known as electrography. Notably, electrography forms the basis for the invention of the photocopier and the development of Xerox technology. EVOdrop water is a device authors use to transmit electromagnetic waves from 350 to 600 Hz, 20 to 40 kHz, and 7 Schumann frequencies under Color Corona Gas Discharge (CCGD) conditions. A comparative analysis of EVOdrop and tap water corona images was made. Furthermore, this analysis investigated physical and chemical processes occurring under high-frequency CCGD conditions. Keywords: CCGD; EVOdrop water.

such as PDP technique, AC impedance spectra and EIS. The study revealed that, in the presence of excess of Cl ions in AS, CR of Cu decreased. This implies that people wearing ornaments or watches made of Cu must be careful about NaCl level in their sweat. Keywords: AS; CR; Cu; electrochemical studies; NaCl influence.

Environmental and health issues have created the urgent need to transition from CrO₄²- legacy to more environment-friendly CC. The various international protocols on CrO₄²- have restricted its usage, thus opening a floodgate of research activities on its urgent replacements. The current study which examines HSCE and V salt takes a cue from earlier outcomes in which a hybrid HSCE and M2MoO4 coating outperformed CrO₄²- coating. The relatively faster diffusion rate of the chelated Mo (VI) complex of hybrid HSCE over Cr (VI) inhibited corrosion and provided a better barrier on the substrate. Thus, this study examined HC from HSCE in combination with V salt, a V salt-based CC and untreated Al 6061. From PDP measurements and EIS studies in a 3.5% NaCl solution, CC from VO4 outperformed HC, and both outclassed untreated 6061 Al. Rct values from EIS studies were 116 (lowest), 1825 and 3434 ohm/cm2 (highest) for uncoated 6061 Al, HSCE/VO4 coating and VO4, respectively. From PDP studies, icorr values were 24.934 x 10-6 (VO4), 33.275 x 10-6 (HSCE/VO4) and 36.64 x 10-6 A/cm2 (6061 Al), respectively, compared to 1.6 x 10-6 A/cm2, for CC from CrO₄², in a similar study. These primary findings might support new opportunities for producing environment-friendly smart hybrid and mono CC based on V compounds for corrosion control on Al in the metal finishing industries. Keywords: 6061 Al; CC; corrosion control; EIS; HC; HSCE from VO4; Rp.

Bm has the best role in the economy of a country. Ln is an essential structural component that is present in all vascular plants’ cell walls. It is essential for the development of connective tissues, since it gives stiffness, strength and resistance to external threats like infections. Ln has numerous economic uses, and its extraction might lead to the development of several novel applications. Therefore, it is of the utmost significance to develop efficient and long-lasting solutions for Ln extraction from Bm. For this reason, one of the goals of the current study was to examine optimized Ln extraction from Bm, SB, rice and WS, by chemical methods. Further, Ln chemical extraction process characterization, optimization, and its applications in resins have herein been carried out. Keywords: Bf; Bm; chemical; greenhouse gas; Ln; LnC; resin.

Corona gas discharge (CGD) is a physical process that occurs when a gas is ionized. It is observed as a bluish glow at high breakdown voltages from 5 to 30 kV. In laboratory conditions, [1] has objectively studied CGD, in the former USSR, in the late 1940s. The method was classified as electrophotography, for recording information. Based on an electrophotographic information recording, Carlson developed xerography in the 1960s. [3] has conducted experiments using electrophotographic CGD methods, to record data. Antonov and co-authors proved that CGD primarily depends on the object’s dielectric permeability rather than on conductivity. [15, 16] have measured photon emission in different types of water. The method is called color coronal spectral analysis. Since 2012, [12] have developed a method for analyzing CGD image, assessing brightness for various water types. The authors consider that, with CGD, information is connected with water dielectric permeability and, thus, with H2O molecules restructuring. The developed method of water classification allows for an integral assessment of H2O characteristics. The experimental sample was classified based on brightness histogram (BH) analysis of CGD radiation images. Keywords: BH; CGD; discharge image; H2O.

EMD was herein applied as a glucose-oxidizing electrode catalyst. ZnO electrode showed considerable electro-catalytic activity for glucose oxidation. The effect of glucose Ct was studied by CV and SWV. The j increased with glucose Ct. Bacteria presence in the reaction environment showed that they tended to adhere to the Zn surface. The biofilm developed on the ZnO electrode surface did not promote glucose oxidation. Keywords: bacteria; CV; EIS; EMD; glucose; oxidation; SEM; SWV; ZnO.

Nano-sized PANI/Mn2CoO4 hybrid was successfully synthesized by diluted polymerization method, for high power SC. The metal oxide incorporation significantly increased the polymer’s crystallinity and electrochemical efficiency. PANI/Mn2CoO4 electrochemical evaluation showed enhanced energy, power density (2.28 and 762.6 W/kg-1, respectively), specific capacitance (470 Fg-1) and columbic efficiency of 87.1%, with long cycling stability up to 1000 cycles. NHP improved capacitive nature and power characteristics were achieved by the synergistic effect between PANI and Mn2CoO4. Keywords: charge-discharge; energy storage; PANI/Mn2CoO4; SC.

MSW or manufacturing WM must be sustainable, to achieve SDG and address health, environmental and economic disposal concerns caused by large amounts of artificial garbage. Locals are put at risk, due to improper MSW management. In Pakistan, MSW output is increasing daily. Urban settlements and other organisations generate a large amount of garbage in various forms, which typically degrades and makes the surroundings unappealing. The soil state in the metropolitan area has decreased, due to irresponsible debris dumping. The dumping of contaminated litter and mixed fluids outside of waste disposal borders raises serious environmental issues on soil and water pollution. This review focused primarily on the impacts of MSW collection on soil and water quality at open waste disposal facilities, as assessed by a mixed soil-WQI. Improper waste disposal techniques, which include open dumping, uncontrolled landfilling and illegal disposal, can lead to contamination that negatively effects soil and water quality. One must also look for sustainable WM options. The consequences related to these gaseous emissions have been widely investigated. Keywords: landfills; MSW; pollution; soil quality.

In this study, gravimetric analysis was used to determine corrosion properties, i.e., WL and CR of welded and tempered UNS G10400 CS exposed to Sw. In order to determine optimal WL and CR, RSM approach was utilized to develop a prediction model. 20 runs of the experiment were used for statistical ANOVA. As response variables, the experimental design matrix included WL and CR. To optimize the results of GC method and develop a predictive regression model, CCD was utilized. By ANOVA, the generated models for WL and CR indicated a significant p-value (which is probability, under the null hypothesis assumption, of obtaining a result equal to or higher than the one observed) of < 0.0001. F-values and R2 showed good statistical correlation between experimental and predicted values. Optimal conditions for WL and CR occurred at 25 °C(as-welded), with an ET of 17 days, and their optimum values were 0.744 g and 0.769 mm/year, respectively. Validation of optimized predicted results showed an UE of 1.6 and 2.9%, for WL and CR, respectively, which was below 5%. This revealed that the generated model adequately predicted CP of welded and tempered UNS G10400 CS in a Sw environment. Keywords: as-welded; GT; optimal conditions; predictive modeling; RSM; UNSG10400 CS.