Search Results (49)

Zn-Fe-Cr coatings were successfully deposited on sintered Nd-Fe-B matrix through the addition of the complexing agent etidronic acid (HEDP) to the plating solution; the electrodeposited process of the metal elements and the corrosion behavior of the coatings were also investigated. Through cyclic voltammetry (CV) tests, it was observed that the reduction potential difference between the metal elements was reduced by the addition of HEDP, which contributed to a more feasible electrodeposited process. The surface of Zn-Fe-Cr coating was covered by a chromate conversion film, and its microstructure was identified as the solid solution of Fe and Cr in Zn matrix. Compared with Zn and Zn-Fe coatings, the corrosion current density (J_corr) of Zn-Fe-Cr coating was decreased to 0.28 × 10⁻⁶ A·cm⁻², and the corrosion potential (E_corr) was increased to −1.01 V. Compared with the Zn and Zn-Fe coatings, the corrosion rate of the Zn-Fe-Cr coating has decreased by 90% and 98%, respectively. The corrosion resistance of coatings was further analyzed by neutral salt spray tests (NSS), and the analysis results showed that a composite oxide layer, composed of ZnO and Cr₂O₃, was formed in the corroded area of Zn-Fe-Cr coating during the corrosion process, which is capable of effectively inhibiting the expansion of the corrosion area. This research provides a promising strategy for ensuring the long-term service integrity of sintered Nd-Fe-B materials in marine environments. Full article

Two diphosphonates, etidronic acid (HEDP) and zoledronic acid (ZOL), were radiolabelled with ¹⁶¹Tb and evaluated as potential bone-targeting radiopharmaceuticals. Radiolabeling was performed at pH 7, achieving high radiolabeling yields (greater than 98%) and demonstrating excellent in vitro stability in saline and human serum. Both radiolabeled complexes exhibited hydrophilic behavior, a strong binding affinity to hydroxyapatite, and moderate to high plasma protein binding. Biodistribution studies in healthy Wistar rats demonstrated that ¹⁶¹Tb-HEDP and ¹⁶¹Tb-ZOL achieve high and stable skeletal uptake with rapid blood clearance and minimal soft tissue accumulation. ¹⁶¹Tb-HEDP favored higher initial bone localization, while ¹⁶¹Tb-ZOL showed lower renal and hepatic accumulation, indicating higher safety and selectivity. Compared to unchelated ¹⁶¹TbCl₃, both diphosphonate complexes exhibited significantly higher bone-to-kidney and bone-to-liver ratios, resulting in superior targeting. Complementary experiments with non-radioactive terbium were performed to investigate the redox behavior and confirm complex formation, providing valuable insight into the stability and binding modes of the ligands. Both terbium and the ligands displayed well-defined redox behavior within the potential range of −1 to 1.7 V, with complex formation evidenced by shifts in the oxidation peaks. Density functional theory (DFT) calculations further supported these findings, showing that both phosphonate groups of a ligand coordinate to Tb³⁺, while the hydroxyl groups in HEDP enable intermolecular hydrogen bonding, contributing to additional structural stabilization. Results encourage further investigations of ¹⁶¹Tb-labeled diphosphonates as promising candidates for radionuclide therapy of bone metastases and other skeletal diseases. Full article

Phosphonate-based antiscalants such as 1-hydroxyethane-1,1-diphosphonic acid (HEDP) are extensively employed in industrial water treatment but pose significant environmental challenges due to their persistence and phosphorus content. In this study, Mg-Al layered double hydroxide (Mg-Al LDH) was synthesized and evaluated for its capacity to adsorb and remove HEDP. Mg-Al LDH showed a pronounced adsorption affinity and an exceptionally high capacity of 276.0 mg g⁻¹ at pH 7.0. The adsorption process was remarkably fast, attaining 97% of equilibrium uptake within 45 min at 298 K. The adsorption data fit well to the Elovich kinetic model and the Langmuir isotherm, indicating that the adsorption process is dominated by chemisorption. Thermodynamic analysis further confirmed its spontaneous nature. Additionally, Mg-Al LDH demonstrated strong tolerance to environmental fluctuations. Characterization techniques, including XRD, FTIR, and zeta potential measurements, confirmed that HEDP adsorption onto Mg-Al LDH primarily occurs via surface complexation with metal sites and electrostatic attraction. These findings demonstrate that Mg-Al LDH is a highly effective adsorbent for removing persistent phosphonate pollutants from wastewater streams. Full article

High-strength galvanized parallel steel wire (HSGPSW) is a primary load-bearing component in cable-supported bridge structures. However, due to both human and environmental factors, corrosion during its service life is often inevitable, and in severe cases, it may threaten the structural safety of the bridge. In this study, a novel method employing the organic corrosion inhibitor hydroxyethylidene diphosphonic acid (HEDP) is proposed to mitigate the corrosion of HSGPSW. First, electrochemical accelerated corrosion tests were conducted on 48 specimens immersed in HEDP solutions to investigate the effects of three key parameters—HEDP concentration, tensile stress, and inhibition duration—on the mass loss rate of the specimens. Subsequently, tensile tests were performed on the inhibited specimens to obtain their load–displacement curves, and the maximum tensile load under the influence of HEDP was comparatively analyzed. The results show that at an HEDP concentration of 0.12 mol·L⁻¹, the inhibition efficiency reached 40.31%, but it became saturated when the concentration exceeded 0.08 mol·L⁻¹. At a tensile stress of 7.5 kN, the inhibition efficiency decreased to 13.24%, with passive film breakdown identified as the primary cause of performance degradation. Energy-dispersive spectroscopy (EDS) analysis revealed that HEDP significantly stunts zinc layer dissolution, thereby enhancing initial corrosion protection, while mechanical tests indicated that its ability to slow the degradation of tensile performance diminishes after film rupture. The corrosion inhibition mechanism is attributed mainly to the synergistic effect of anodic suppression and interfacial coordination. This study provides a new method and novel insights for the corrosion protection of high-strength galvanized HSGPSW in cable-supported bridge structures. Full article

The adhesion of endodontic sealers to dentin may be influenced both by the chemical composition of the sealer and the final irrigation protocol. The aim of this study was to examine the push-out bond strength of three differently formulated bioceramic sealers to root canal dentin, after different irrigation protocols. Four cavities were prepared in dentine discs obtained from middle thirds of third molars with fused roots. Discs were randomly divided into three groups (n = 8). Group 1: specimens were immersed in 2.5% NaOCl; group 2: in 2.5% NaOCl followed by 17% EDTA; and group 3: in a solution of 2.5% NaOCl with 9% etidronic acid (HEDP). The cavities on each disk were filled with four tested sealers: AH Plus Bioceramic, Bio C Angelus, BioRoot RCS, and AH Plus (n = 8 per sealer). The push-out bond strength test was performed after 7 days. The data were statistically analyzed using two-way analysis of variance with the Bonferroni post hoc test (α = 0.05). Irrigation with NaOCl resulted in significantly lower bond strength values of the sealers in comparison to NaOCl/EDTA and NaOCl/HEDP groups. In the NaOCl and NaOCl/HEDP groups, BioRoot RCS showed similar push-out bond strength compared to AH Plus and significantly higher compared to Bio-C and AH Plus Bioceramic. In the NaOCl/EDTA group, bioceramic sealers achieved a significantly weaker bond strength compared to AH Plus. The bond strength of BioRoot RCS was significantly higher compared to Bio-C and AH Plus Bioceramic. The irrigation protocols and the chemical composition of the sealers significantly influenced their bond strength to dentin. Epoxy resin-based sealer achieved the strongest bond strength, while within bioceramic sealers, the highest values were obtained for BioRoot RCS and the lowest for AH Plus Bioceramic. Full article

Background/Objectives: This study aimed to assess and compare the elimination of the smear layer and microhardness of dentin in root canals after sequential versus continuous chelation using different agitation techniques. Methods: Sixty-four palatal roots of upper first molars were instrumented to size X3 (Protaper Next files). According to the irrigant solution, samples were assigned to two groups (N = 32/group), 3% NaOCl irrigation followed by 17% EDTA (sequential chelation (SC)), or dual-rinse (3% NaOCl/9% HEDP) irrigation (continuous chelation (CC)). Each group has been divided into four subgroups (n = 8/subgroup), based on agitation techniques used: conventional needle (CN) (control group), EndoActivator (EA), ultrasonic agitation (UAI), and Er.Cr.YSGG 2780 nm (laser). SEM images assessed the smear layer, and Vicker microhardness (VHN) was performed at 50 and 100 µm depths. Data were analyzed using: Kruskal–Wallis, Wilcoxon, and the Mann–Whitney U test. Statistical significance was set at p < 0.05. Results: In the UAI and laser agitation, CC significantly reduced the smear layer presence compared to SC in the apical and coronal thirds, respectively (p < 0.05), and no significant differences were observed in the CN and EA groups between SC and CC (p > 0.05). There were significantly higher VHNs of dentine in CC groups than in SC groups in all sections and depths, except in the apical of the CN group at 50 µm and the coronal section of EA and UAI groups at 100 µm. Conclusions: CC was comparable to SC in smear layer removal. CC had a less detrimental effect on dentin compared with SC. Full article

Drip irrigation offers greater water use efficiency than conventional furrow irrigation practises, though routine maintenance is required for optimal performance. The continuous use of low concentrations (10 ppm) of H₂O₂ stabilized with hydroxyethylidene diphosphonic acid (HEDP) at two concentrations (H₂O_{2 Low} containing 1 ppb and H₂O_{2 High} containing 1 ppm of HEDP) in drip irrigation was evaluated in terms of emitter, crop and yield performance across three crop species. Emitter flow rates (EFRs) for subsurface drip in sugarcane were higher by 16% and root intrusion into emitters was almost halved with H₂O_{2 Low}. For above-ground suspended drip lines with table grape, blockage of emitters due to biofouling was reduced by 50% in H₂O_{2 Low} compared to the control or H₂O_{2 High} within the second year of use, and the extent of emitters with visible biofouling was reduced even more. Soil microbiology did not differ markedly between treatments in any of the crops, even over four years of use. However, soil microbial carbon and soil carbon were reduced by H₂O_{2 Low} in the sugarcane trial. Yield increases of 9, 25, and 49% occurred in chilli, table grape, and sugarcane, respectively, for the continuous H₂O_{2 Low} treatment compared to the control. The yield increases with H₂O_{2 Low} could be associated with increased uniformity in water supply and/or oxygen supply to plant roots. Full article

Inhalation of aerosolized uranium is recognized as a principal mode of exposure, posing significant risks of damage to the lungs, kidneys, and other vital organs. To enhance nuclide elimination from the body, chelating agents are employed; however, single-component chelators often exhibit limited spectral activity and low effectiveness, resulting in toxicologically relevant concentrations. We have developed a composite chelating agent composed of 3,4,3-Li(1,2-HOPO), DFP, and HEDP in optimized ratios, demonstrating marked improvements in eliminating inhaled uranium. The selection of these components was initially guided by an agarose gel dynamics method, focusing on uranium binding and removal efficacy. Optimization of the formula was conducted through response surface methodology in a cellular model. The compound’s ability to enhance survival rates in mice subjected to acute uranium inhalation was confirmed, showing a dose-dependent improvement in survival in severely affected mice. Comparative assessments indicated that this multifaceted chelating agent substantially surpasses the uranium tissue clearance achieved by individual chelating agents. Full article

This study presents the development and application of a mathematical optimization model to improve decision-making in the supply chain for high-energy-density pellet (HEDP) production and commercialization. Focused on the Metropolitan Region of Chile, the research involved a detailed analysis of key supply chain components, including identifying landfills and controlled dumps, waste volume assessments, plant location analysis, technology evaluation, and market potential exploration. The model revealed that the available raw material in the region was sufficient to meet 100% of HEDP demand, with a surplus of 2,161,952 tons remaining after satisfying maximum demand. An optimization analysis of potential plant locations identified Santa Marta as the optimal choice, resulting in annual cost savings of USD 100,000 compared to other sites. This work underscores the role of mathematical optimization in enhancing supply chain efficiency for biomass-based energy products, offering valuable insights for strategic decision-making in similar contexts. Full article

Organophosphates are a type of emerging environmental contaminant, which can be removed effectively by adsorption. Here, modified steel slag was examined for its adsorptive performance in the removal of hydroxyethylidene diphosphonic acid (HEDP) from water. Compared to acid (55.3%, maximum removal rate) and base (85.5%) modification, high-temperature modification (90.6%) significantly enhanced steel slag’s adsorption capacity for HEDP, surpassing that of unmodified slag (71.2%). Kinetic analyses elucidated a two-phase adsorption process—initial rapid adsorption followed by a slower equilibrium phase. The results of adsorption energy analysis showed that modified steel slag preferentially occupied the sites with higher energy, which promoted the adsorption. After five regeneration cycles, the adsorption properties of the material were not significantly reduced, which indicates that the material has good application potential. Microscopic and spectroscopic techniques, including SEM-EDS, FTIR, and XPS, were employed to uncover the surface chemistry and structural changes responsible for the enhanced adsorption efficiency. The adsorption mechanism of HEDP on steel slag is a complete process guided by hydrogen bonding interactions, strengthened surface complexation, and optimized ligand exchange. This study advances the sustainable utilization of industrial waste materials and contributes significantly to the development of innovative water treatment technologies. Full article

This study outlines a method for preparing a complex involving glycoluril and melamine (GU-ME). The structure of the resultant complex was analyzed using IR and NMR spectroscopy. In the subsequent phase, the polymer GUMEFA was derived from the resultant complex, employing hydroxyethylidene diphosphonic acid (HEDP) as a sustainable plasticizer, with a proposed chemical mechanism for its formation. The molecular weight of the resulting GUMEFA was analyzed, and the formation chemistry was proposed. GUMEFA was characterized, and its free formaldehyde and methylol group contents were investigated. It was observed that GUMEFA prepared with HEDP contained approximately 1.15–1.34 wt.% free formaldehyde and 1.56–0.54 wt.% methylol groups. These findings provide valuable insights for developing resins of different compositions and applications, thereby paving the way for producing composite materials with tailored properties. Full article

The effect of tetrasodium of 1-hydroxy ethylidene-1, 1-diphosphonic acid (HEDP·4Na) on the microstructure and phase characterization of alkali-activated fly ash–slag (AAFS) materials is not clear or well documented. In this study, XRD, DTG, TAM-air, and SEM analyses of AAFS were used to identify the microstructural changes in AAFS made with HEDP·4Na. Meanwhile, the workability and compressive strength of AAFS were evaluated. The results demonstrated that the early-age alkaline-activated reactions were retarded due to the addition of HEDP·4Na in the AAFS mixture. However, the degree of gel formation was relatively increased at a later age in the AAFS made with HEDP·4Na compared to the plain AAFS mixture. Additionally, in comparison to the control group, the incorporation of HEDP·4Na in AAFS specimens resulted in improved flowability, with increments of 5%, 15%, and 24% for concentrations of 0.1%, 0.2%, and 0.3%, respectively. The initial and final setting times were prolonged by 5% to 50%, indicating a beneficial impact on the rheological properties of the AAFS fresh mixture. Furthermore, the addition of HEDP·4Na led to an improvement in compressive strength in the AAFS mixtures, with enhancements ranging from 13% to 16% at 28 days compared to the control group. With the presence of HEDP·4Na, the increase in the degree of reactions shifted to the formation of gel phases, like C-S-H, through the combined measurement of TGA, XRD, and SEM, resulting in a denser microstructure in the AAFS matrix. This study presents novel insights into the intricate compatibility between the properties of AAFS mixtures and HEDP·4Na, facilitating a more profound comprehension of the potential improvements in the sustainable development of AAFS systems. Full article

Regenerated water serves as a supplementary source for circulating cooling water systems, but it often fosters microbial growth within pipelines. Given its widespread use as a corrosion inhibitor, understanding HEDP’s efficacy in microbial environments and its impact on microorganisms is imperative. This study established an iron bacterial system by isolating and enriching iron bacteria. Through a comprehensive approach incorporating corrosion weight loss analysis, XPS analysis, SEM electron microscopy, as well as microbial and electrochemical testing, the corrosion inhibition behavior and mechanism of HEDP within the iron bacterial system were investigated. The findings reveal that within the iron bacterial system, HEDP achieves a corrosion inhibition rate of 76% following four distinct stages—weakening, strengthening, stabilizing, and further strengthening—underscoring its robust corrosion inhibition capability. Moreover, HEDP enhances the density of biofilms and elevates the activation energy of carbon steel interfaces. It alternates with oxygen to continuously suppress the activity of IRB while gradually inhibiting the activity of IOB. This process culminates in a corrosion inhibition mechanism where cathodic inhibition predominates, supported by anodic inhibition as a complementary mechanism. Full article

This study investigates the pH values and optical characteristics of Dual Rinse HEDP, either independently or combined with sodium hypochlorite (NaOCl), and compares them to other irrigants used in endodontics. The solutions used in this study were commercially acquired and prepared, followed by pH measurements using a pH meter and spectral analysis using UV/Vis spectrophotometry in specified wavelengths of the ultraviolet (UV) C (190–280 nm), UVB (281–315 nm), UVA (316–400 nm), visible light (VL) (401–780 nm), and near-infrared (NIR) spectra (781–1100 nm). The pH analysis revealed alkaline values for NaOCl, EDTA, Dual Rinse HEDP, and the HEDP + NaOCl combination, an acidic value for citric acid, and nearly neutral values for chlorhexidine and distilled water. Spectral analysis revealed the notable absorption characteristics of endodontic irrigants. In the UV range, all solutions exhibited higher absorption values to water (p < 0.05), with Dual Rinse HEDP resembling EDTA and citric acid, and HEDP + NaOCl resembling NaOCl. The NIR region highlights absorption peaks around 975 nm for all solutions, including NaOCl and Dual Rinse HEDP + NaOCl, suggesting potential applications in laser-activated irrigation. This study provides comprehensive insights into the pH and optical features of endodontic irrigants, emphasizing their potential roles in enhancing disinfection strategies and optimizing laser-activated irrigation protocols. Full article

In this study, we have successfully demonstrated a high-energy subpicosecond Yb:YAG laser system based on chirped-pulse regenerative amplification. Our experimental results demonstrate a pulse energy of 3 mJ with a pulse duration of 829.8 fs and a repetition rate of 1 kHz. Additionally, we conducted an extensive investigation into the system’s recompression capability under various modulation and seeding conditions. Our findings suggest that the system can achieve effective recompression over a broad range of parameters, with the ability to compensate for a considerable degree of chirp. Our study provides valuable insights into the fundamental physic of high-energy laser systems and the performance characteristics of chirped-pulse regenerative amplification. Full article