Concentrated Chloride Solutions Research Articles

The combined leaching of copper, gold and uranium in chloride solutions. II. Concentrate leach tests

This study of the simultaneous leaching of copper, gold and uranium from a flotation concentrate is aimed at establishing the conditions that could be applied in a possible heap leach process that would recover all three metals (plus silver, if present) in a single step. The results obtained in this study confirm the results obtained in Part I (Nicol et al., 2024) that enhanced rates for leaching of chalcopyrite from flotation concentrates from two different sources can be obtained in acidic chloride solutions in the presence of chlorate ions. The measurements of the solution potentials during leaching with chlorate are similar to those obtained previously and confirm that chlorine generated by the chlorate-chloride reaction is the active oxidant.Uranium is dissolved even in the absence of chlorate by iron(III) as the oxidant. The latter is re-generated by reaction of iron(II) with chlorate. The dissolution of gold requires higher potentials, and it is only leached when the potential approaches 1.0 V in concentrated chloride solutions. At low chloride concentrations (1 M), gold is not dissolved because of apparent passivation.An electrochemical study of the behaviour of gold in chloride solutions in the presence of sulfide ions has shown that the passivation is probably the result of the formation of a layer of Au2S on the gold surface at low potentials before the addition of chlorate to the leach solutions i.e., before the generation of sufficient chlorine concentrations. At potentials above about 0.95 V Au2S is unstable being oxidised to AuCl2− and elemental sulfur thereby eliminating passivation.

One-step formation of polymorphous sperm-like microswimmers by vortex turbulence-assisted microfluidics

Microswimmers are considered promising candidates for active cargo delivery to benefit a wide spectrum of biomedical applications. Yet, big challenges still remain in designing the microswimmers with effective propelling, desirable loading and adaptive releasing abilities all in one. Inspired by the morphology and biofunction of spermatozoa, we report a one-step formation strategy of polymorphous sperm-like magnetic microswimmers (PSMs) by developing a vortex turbulence-assisted microfluidics (VTAM) platform. The fabricated PSM is biodegradable with a core-shell head and flexible tail, and their morphology can be adjusted by vortex flow rotation speed and calcium chloride solution concentration. Benefiting from the sperm-like design, our PSM exhibits both effective motion ability under remote mag/netic actuation and protective encapsulation ability for material loading. Further, it can also realize the stable sustain release after alginate-chitosan-alginate (ACA) layer coating modification. This research proposes and verifies a new strategy for the sperm-like microswimmer construction, offering an alternative solution for the target delivery of diverse drugs and biologics for future biomedical treatment. Moreover, the proposed VTAM could also be a general method for other sophisticated polymorphous structures fabrication that isn’t achievable by conventional laminar flow.

Laboratory study on the transformation of oil-water interface properties under direct current electric field

Interface tension is one of the important mechanisms that affect crude oil recovery and plays an important role in the development of tight oil reservoirs. Electrical-enhanced oil recovery can be used as a technology to reduce interfacial tension and improve crude oil recovery. In the previous research process of Electrical-enhanced oil recovery, the focus was more on the influence of electric field on wettability, and the understanding of the changes in interfacial tension under electric field action is not yet comprehensive. This article designs an orthogonal experiment to study the effect of electric field on oil-water properties. The degree of influence of three factors, namely sodium chloride solution concentration (C), direct current voltage (V), and voltage action time (t), on interfacial tension is studied. Gas chromatography, four component analysis, and Fourier transform infrared spectroscopy are combined to discuss the mechanism of the influence of changes in solution pH, crude oil components, and oil phase functional groups on interfacial tension. The results show that an external electric field can effectively reduce the interfacial tension between oil and water, and the maximum change in interfacial tension after the experiment can be reduced from 23.21 mN/m to 0.37 mN/m; Through range analysis, it can be concluded that the concentration of sodium chloride solution has the greatest impact on interfacial tension, followed by DC voltage and voltage action time. The optimal experimental conditions are 0.5 mol/L sodium chloride solution, 10 V DC voltage, and a voltage action time of 18 h, and the change in interfacial tension is related to the increase in pH value. The change in crude oil composition is also an important reason for the decrease in interfacial tension under external electric fields. Finally, Fourier transform infrared spectroscopy was used to determine that under the action of an electric field, the increase in pH of the sodium chloride solution resulted in the formation of carboxylate salts through chemical reactions between alkaline substances of solution and acidic substances of the oil, which were the key factors in reducing interfacial tension. This study helps to understand and explore the principles and mechanisms of Electrical-enhanced oil recovery in improving oil recovery, with the aim of contributing to the development and promotion of Electrical-enhanced oil recovery technology.

The influences of traces of oxygen and sulfide on the corrosion of copper in concentrated chloride solutions

The corrosion of wrought, electrodeposited, and cold spray deposited copper was electrochemically monitored for ∼160 days in 3 M NaCl solution containing traces of sulfide under anoxic and Ar-purged conditions. Corroded specimens were analyzed using scanning electron microscopy and Raman and X-ray photoelectron/Auger spectroscopies. Under anoxic conditions, corrosion was supported by sulfide only and the rate decreased with time causing only minor damage. Under low oxygen conditions maintained by Ar-purging, the rate increased with time and significant damage was observed, attributed to oxy-sulfur species formation. These results suggest that oxy-sulfur species, not just sulfide, are required to cause intergranular corrosion.

Effects of Mepiquat Chloride on Physiology of Soybean under Drought Stress

Background: Drought is an important factor restricting the development of agriculture. In recent years, plant growth regulators have achieved more results in improving crop stress resistance. The physiological mechanism of exogenous application of mepiquat chloride on soybean seedlings has undergone significant changes under drought stress. Methods: In order to study the effect of exogenous chlorine on the physiology of soybean under drought stress., ‘Heinong 65’ was used as the experimental material, 15% PEG-6000 was used to simulate drought stress and different concentrations of mepiquat chloride solution (100, 300, 500, 700 mg/L) were sprayed at the three-leaf stage of soybean growth by pot method. The dry matter accumulation, auxin (IAA), zeatin (ZA), gibberellin (GA3), abscisic acid (ABA) content and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) activity of soybean were determined. Result: The results showed that the activities of antioxidant enzymes SOD, POD, CAT and APX in soybean leaves under drought stress were significantly increased by the treatment of appropriate concentration of mepiquat chloride solution. IAA, GA3 and ZA endogenous hormone levels increased, dry matter accumulation increased, root-shoot ratio and ABA endogenous hormone levels decreased significantly. It can be seen that mepiquat chloride treatment can improve the antioxidant capacity, promote the growth of soybean seedlings under drought stress and effectively alleviate the inhibition of drought stress on soybean growth and development.

Optimized modes of iron removal from highly concentrated chloride solutions amid transition to nickel electrowinning process

Optimized modes of iron removal from highly concentrated chloride solutions amid transition to nickel electrowinning process

Optical activity of trans-4-hydroxy-L-proline in sodium chloride solutions

The optical activity oftrans-4-hydroxy-L-prolinein deionized water and sodium chloride solutions of various concentrations has been investigated through polarimetry. The specific rotation of thecompounddecreases in the magnitude in solutions with the salt concentration of 0 to 2.000 Mbut does not change significantly in the concentration range of 2.500 to 3.500 M. The specific rotations at the salt concentrations from 4.000 to 5.000 M are smaller in the magnitude and do not vary significantly. Theconcentration dependence is explained basedon thecorrelation between the specific rotation and the square root of the solutiondielectric constant.

In Vitro Studies on the Effects of Aqueous Extracts of Syzygium Aromaticum Linn. (Cloves) and Zingiber Officinale Roscoe (Ginger) on Erythrocyte Osmotic Fragility in Sickle Cells

Sickle cell disease is a genetically inherited blood disease that is characterized by the production of abnormal erythrocytes, shaped like a sickle. Definite cure for sickle cell disease is yet to be established, therefore, palliative methods such as antioxidant agents which reduce occurrence of intravascular haemolysis are employed. Naturally occurring antioxidants are found in Syzygium aromaticum Linn. (Clove) and Zingiber officinale (ginger) as documented by previous researches are therefore tested on the erythrocyte osmotic fragility of sickle cell red blood cells (RBC). Aqueous extracts of clove and ginger were obtained by maceration and antioxidant activity of the extracts was determined by 2, 2,-diphenyl-1-picryl-hydrazyl (DPPH) using ascorbate as standard. Blood samples from twenty five sickle cell disease subjects were collected and divided into five groups. Group one was control, groups two and three were incubated with 1mg/ml and 10mg/ml of clove extract respectively, while groups four and five were incubated with 1mg/ml and 10mg/ml of ginger extract respectively. Erythrocyte osmotic fragility was determined using graded series of hypotonic Sodium Chloride (NaCl) solutions of concentrations ranging from 0.1% to 0.9%. Analysis of Variance (ANOVA) and Turkey test was used to analyze data and test of significance was applied at p?0.05. The results revealed the presence of phenols, alkaloids, flavonoid and tannins in both clove and ginger extracts; glycosides were present in ginger but absent in clove. Antioxidant at low concentration of 50µg/ ml showed percentage inhibition of clove and ginger were 67.43% and 11.87%, respectively, and that of ascorbate was 20.15%. At high concentration of 250µg/ml, clove and ginger had percentage inhibition of 93.8% and 81.18% respectively, while ascorbate had 84.06%. Erythrocyte osmotic fragility test results showed complete haemolysis at 0.1% NaCl concentration in all groups. At 0.2% NaCl concentration, percentage haemolysis of the group treated with 10mg of clove 69.12 ± 0.05, was significantly lower (p?0.05) than the control (98.12 ± 0.05), while the group treated with 10mg ginger extract showed 98.02 ± 0.04 which is not significantly lower (p?0.05) than that of the control. At 0.5% NaCl concentration, percentage haemolysis of groups treated with 10mg clove extract and 10mg ginger extract were 8.400.18 and 20.42 ± 0.18, respectively, which were significantly lower (p?0.05) than that of the control group (45.90 ± 0.10). The groups treated with 1mg clove extract and 1mg ginger extract showed percentage haemolysis values of 38.04 ± 0.10 and 30.02 ± 0.10 respectively at 0.5% NaCl concentration which were significantly lower (p?0.05) than the control group (45.90 ± 0.10). Clove showed higher antioxidant activity than ginger. Both plants also demonstrated a capacity for maintaining erythrocyte membrane stability, with clove being better at lowering erythrocyte fragility than ginger.

Temperature compensation measurements in the detection of glucose and sodium chloride solution concentration based on SPR in the optical fiber

The temperature variation is one of the main error factors in the process of glucose and sodium chloride solution concentrations detection based on optical fiber sensor. In this paper, we proposed a sensor with temperature compensation, which can detect the temperature while measuring the concentrations of glucose or sodium chloride solution. The dual-channel design enables the sensor to obtain accurate measurement results of glucose and sodium chloride concentrations, and also to monitor the environmental temperature simultaneously. The deposition of zinc oxide film not only enhances the sensitivity of the sensor but also prevents oxidation of the silver film. The high stability of polydimethylsiloxane (PDMS) ensures that the two sensing channels of the sensor do not interfere with each other. The proposed dual-channel sensor offers advantages of low cost, a simple structure, and high sensitivity, with potential applications in the fields of food science and biochemistry.

Collagen IV of basement membranes: III. Chloride pressure is a primordial innovation that drives and maintains the assembly of scaffolds

Collagen IV scaffold is a primordial innovation enabling the assembly of a fundamental architectural unit of epithelial tissues-a basement membrane attached to polarized cells. A family of six α-chains (α1 to α6) coassemble into three distinct protomers that form supramolecular scaffolds, noted as collagen IVα121, collagen IVα345, and collagen IVα121-α556. Chloride ions play a pivotal role in scaffold assembly, based on studies of NC1 hexamers from mammalian tissues. First, Cl- activates a molecular switch within trimeric NC1 domains that initiates protomer oligomerization, forming an NC1 hexamer between adjoining protomers. Second, Cl- stabilizes the hexamer structure. Whether this Cl--dependent mechanism is of fundamental importance in animal evolution is unknown. Here, we developed a simple invitro method of SDS-PAGE to determine the role of solution Cl- in hexamer stability. Hexamers were characterized from 34 animal species across 15 major phyla, including the basal Cnidarian and Ctenophora phyla. We found that solution Cl- stabilized the quaternary hexamer structure across all phyla except Ctenophora, Ecdysozoa, and Rotifera. Further analysis of hexamers from peroxidasin knockout mice, a model for decreasing hexamer crosslinks, showed that solution Cl- also stabilized the hexamer surface conformation. The presence of sufficient chloride concentration in solution or "chloride pressure" dynamically maintains the native form of the hexamer. Collectively, our findings revealed that chloride pressure on the outside of cells is a primordial innovation that drives and maintains the quaternary and conformational structure of NC1 hexamers of collagen IV scaffolds.

Investigation of the dynamic compressive mechanical properties of concrete under the combined effects of freeze–thaw and salt erosion

The objective of this study is to investigate the dynamic compressive mechanical properties of concrete under the combined effects of freeze–thaw (F-T) and salt erosion. The Split Hopkinson Pressure Bar (SHPB) test system was employed to conduct dynamic compression tests on concrete specimens subjected to 0 ∼ 250 cycles of F-T in NaCl solutions with concentrations ranging from 0 % to 8 %. The influence of strain rate, F-T cycles, and chloride concentration on the dynamic properties of concrete were analyzed, and a constitutive model considering rate-dependency was developed to describe its compressive mechanical response. The research findings suggest that the dynamic compressive strength of concrete gradually increases with an increase in strain rate, indicating a strengthening effect due to higher strain rates. Additionally, the dynamic growth factor exhibits an exponential relationship with the logarithm of strain rate. Moreover, an increase in the number of F-T cycles results in a gradual reduction in the dynamic compressive strength of concrete and an accompanying increase in specimen fracture. Furthermore, the dynamic compressive strength of concrete exhibits a non-linear trend concerning chloride solution concentration: initially decreasing and subsequently increasing. The minimum compressive strength is observed at a concentration of 3.5 %, indicating the most severe damage to the concrete. However, it should be noted that a higher strain rate mitigates the influence of chloride solution concentration on specimen breakage. To comprehensively understand the mechanical behavior of concrete under combined F-T and salt erosion effects, we propose a dynamic constitutive model based on established mechanical and damage theories relevant to composite materials. The experimental results demonstrate that the proposed model effectively captures the mechanical response of concrete subjected to the combined influence of F-T and salt erosion.

Strontium Chloride Improves Reproductive Function and Alters Gut Microbiota in Male Rats.

Strontium (Sr) is an essential trace element in the human body and plays an important role in regulating male reproductive health. Recent studies have shown that gut flora plays a key role in maintaining spermatogenesis, as well as testicular health, through the gut-testis axis. At present, it is unclear whether gut microbiota can mediate the effects of Sr on sperm quality, and what the underlying mechanisms may be. We investigated the effects of different concentrations of strontium chloride (SrCl2) solutions (0, 50, 100, and 200 mg/kg BW) on reproductive function and gut microbiota in male Wistar rats (6-8 weeks, 250 ± 20 g). All the animals were euthanized after 37 days of treatment. The Sr-50 group significantly increased sperm concentration, sperm motility, and sperm viability in rats. After Sr treatment, serum and testicular testosterone (T) and Sr levels increased in a dose-dependent manner with increasing Sr concentration. At the same time, we also found that testicular marker enzymes (ACP, LDH) and testosterone marker genes (StAR, 3β-HSD, and Cyp11a1) increased significantly in varying degrees after Sr treatment, while serum NO levels decreased significantly in a dose-dependent manner. Further investigation of intestinal flora showed that SrCl2 affected the composition of gut microbiome, but did not affect the richness and diversity of gut microbiota. Sr treatment reduced the number of bacteria with negative effects on reproductive health, such as Bacteroidetes, Tenericutes, Romboutsia, Ruminococcaceae_UCG_014, Weissella, and Eubacterium_coprostanoligenes_group, and added bacteria with negative effects on reproductive health, such as Jeotgalicoccus. To further explore the Sr and the relationship between the gut microbiota, we conducted a Spearman correlation analysis, and the results showed that the gut microbiota was closely correlated with Sr content in serum and testicular tissue, sex hormone levels, and testicular marker enzymes. Additionally, gut microbiota can also regulate each other and jointly maintain the homeostasis of the body's internal environment. However, we found no significant correlation between intestinal flora and sperm quality in this study, which may be related to the small sample size of our 16S rDNA sequencing. In conclusion, the Sr-50 group significantly increased T levels and sperm quality, and improved the levels of testicular marker enzymes and testosterone marker genes in the rats. Sr treatment altered the gut flora of the rats. However, further analysis of the effects of gut microbiota in mediating the effects of SrCl2 on male reproductive function is needed. This study may improve the current understanding of the interaction between Sr, reproductive health, and gut microbiota, providing evidence for the development of Sr-rich foods and the prevention of male fertility decline.

Electrochemical responses of carbon steel in ordinary Portland cement blended with calcium sulfoaluminate cement

This work investigated the passivation and chloride-induced corrosion of carbon steel exposed to an extract solution (PCSA) of ordinary Portland cement (OPC) blended with calcium sulfoaluminate (CSA) cement. As evaluated by EIS and XPS measurements, carbon steel gained inferior passivity by forming a thinner and less protective passive film in PCSA solution compared with that in the pure OPC solution. However, after chloride attack, comparable corrosion resistance was confirmed for steel exposed to both solutions. Furthermore, enhanced pitting corrosion resistance was identified for steel after 30 d of immersion in PCSA solution, which was mainly attributed to the formation of an Al-rich layer on the steel surface as well as the reduced chloride concentration in solution by the unreacted aluminum phase.

Potentiodynamic Study of The Effects of Nickel on The Electrodeposition of Zinc from Chloride Media

Abstract. The potentiodynamic experiments of the nickel effects on the zinc electrodeposition have been done to understand the impact of Ni impurities on the electrowinning of Zn from spent pickling liquor. The nickel chloride solutions of Ni concentrations 90 and 1 g/dm3 were used as the electrolytes. The latter was also mixed with 90 g/dm3 Zn in the experiments. All the runs were carried out at room temperature with 40 mV/s continuous polarization speed and with 1/s sampling rate. It was observed that nickel electrodeposition from chloride media containing 90 g/dm3 Ni started with the generation of hydrogen bubbles, entirely blocking the cathode surface. Only a slight current development was observed until the polarization potential ~ -0,8 V. The visual observation showed bubbles also formed at the anode, which may represent chlorine and/or oxygen evolution. While, in the electrodeposition of nickel with only 1 g/dm3 Ni concentration in the electrolyte, metal deposition was hardly observed, but visible hydrogen bubbles constantly blocked the cathode surface. A similar tendency was observed in the mixed-solution electrolysis cell; the initial tiny bubbles accumulated at the cathode surface more than in the pure Zn solution. The enhancement of H2 evolution indicates how nickel deposition may contribute to the loss of useful current in the process of Zn electrodeposition. The mass of nickel deposited from the mixed solutions significantly decreases as the Ni concentration decreases in the electrolyte, while the mass of deposited zinc is relatively constant. It means that the purity of the produced Zn is appreciably higher – with respect to Ni – if nickel is efficiently eliminated from the solution before electrowinning.

Propidium Monoazide (PMAxx)-Recombinase Polymerase Amplification Exo (RPA Exo) Assay for Rapid Detection of Burkholderia cepacia Complex in Chlorhexidine Gluconate (CHX) and Benzalkonium Chloride (BZK) Solutions.

Both sterile and non-sterile pharmaceutical products, which include antiseptics, have been recalled due to Burkholderia cepacia complex (BCC) contamination. Therefore, minimizing the frequency of outbreaks may be conducive to the development of a quick and sensitive approach that can distinguish between live and dead loads of BCC. We have assessed an exo probe-based recombinase polymerase amplification (RPA) with 10 µM propidium monoazide (PMAxx) for selective detection of live/dead BCC cells in various concentrations of antiseptics (i.e., chlorhexidine gluconate (CHX) and benzalkonium chloride (BZK) solutions) after 24 h. The optimized assay conducted using a set of primer-probes targeting gbpT was performed at 40 °C for 20 min and shows a detection limit of 10 pg/µL of genomic DNA from B. cenocepacia J2315, equivalent to 104 colony-forming units (CFU/mL). The specificity of a newly designed primer and probe was 80% (20 negatives out of 25). The readings for total cells (i.e., without PMAxx) from 200 µg/mL CHX using PMAxx-RPA exo assay was 310 relative fluorescence units (RFU), compared to 129 RFU with PMAxx (i.e., live cells). Furthermore, in 50-500 µg/mL BZK-treated cells, a difference in the detection rate was observed between the PMAxx-RPA exo assay in live cells (130.4-459.3 RFU) and total cells (207.82-684.5 RFU). This study shows that the PMAxx-RPA exo assay appears to be a valid tool for the simple, rapid and presumptive detection of live BCC cells in antiseptics, thereby ensuring the quality and safety of pharmaceutical products.

Investigating the impact of flow rate and moisture content for different concentration of liquid desiccant solution

The desiccant air conditioning system consists of two processes, namely cooling and dehumidification, in which the air temperature and humidity are controlled in order to provide comfortable thermal conditions. A typical system includes a dehumidifier, indirect evaporative cooler, and regenerator. The desiccant is selected depending on its ability to absorb water vapor present in the air. In this study, calcium chloride solution was used as a desiccant for the desiccant solution regeneration process, and a flat plate solar collector was employed. Different variables, such as the primary air flow rate, desiccant flow rate, and the concentration of the desiccant solution, were changed during the experiments. The impact of these variables on the performance parameters of the desiccant system such as moisture removal rate, moisture efficiency, enthalpy efficiency, sensible heat ratio, and the mass transfer coefficient was studied. The obtained results revealed that as the solution concentration and the flow rate of primary air increase, the moisture removal rate, sensible heat ratio, and mass transfer coefficient increase. A particular value of inlet primary air flow rate (0.18Kg/s), an increase in the inlet concentration of calcium chloride solution from 0.85 to 0.95 leads to a rise in moisture removal rate, sensible heat ratio, and mass transfer coefficient of (1.1 _1.65) g/s, (0.18-0.25), and (0.01075-0.0123) m/s respectively. While at a certain inlet concentration of a desiccant solution (0.95), increasing the inlet primary air flow rate from 0.1Kg/s to 0.18Kg/s leads to an increase in the moisture removal rate, sensible heat ratio, and mass transfer coefficient o (0.94-1.26) g/s, (0.24-0.26), and(0.0038 -0.011) m/s respectively.

Morphological Evolution of Gold Nanoparticles Synthesized via Solution Plasma Sputtering: Effect of Sodium Chloride Concentration and Storage Time

Morphological control of gold nanoparticles (AuNPs) is vital for tuning their optical, chemical, physical, and catalytic properties for desired specific applications. Despite numerous efforts dedicated in recent years, controlling the morphology of AuNPs synthesized via solution plasma sputtering (SPS) remains a challenge, requiring further investigation. Herein, AuNPs were synthesized via SPS in sodium chloride (NaCl) solutions of various concentrations (0.5, 1, 2, and 5 mM). Evolutions of localized surface plasmon resonance and morphology of AuNPs over a 30 day storage period were thoroughly examined using ultraviolet–visible spectroscopy and field-emission transmission electron microscopy. The formation and growth mechanisms of AuNPs during and after synthesis provide more insights into this nascent field. At the initial storage time, AuNPs with chain-like structures were observed at all the NaCl concentrations. Their size tended to increase from 6 to 10 nm with a broader size distribution with increasing NaCl concentration. At a prolonged storage time of 15 days, AuNPs became smaller and more isolated at all NaCl concentrations owing to the oxidative etching effect. After 30 days of storage, the number of Au ions dissolved from etching slowly reduced and grew on the AuNPs, affording increased particle sizes. The interplay between etching and growth processes proceeded until reaching equilibrium. AuNPs exhibited good colloidal stability at low NaCl concentrations (i.e., 0.5, 1, and 2 mM); however, coalescence and sedimentation occurred at a high NaCl concentration of 5 mM owing to a considerable reduction in the electrical double-layer thickness. These results demonstrated that the NaCl concentration and storage time crucially affect the morphological evolution and stability of AuNPs synthesized via SPS.

Anodic Etching of Amorphous Ni81P19 Alloy in Hot Concentrated Chloride Solution for Enhanced Hydrogen Evolution in Alkaline Water Electrolysis

AbstractHighly active and easily available electrocatalysts are of great importance for a wider use of water electrolysis for hydrogen production. Herein, electroactivity toward hydrogen evolution reaction was examined in 1.0 M KOH on commercial Ni81P19 (MBF‐60) and Ni70Cr6Fe2B14Si8 (MBF‐20A) amorphous alloys and for comparison on Ni, untreated and modified by anodic etching in hot concentrated NaCl solutions. This treatment increased the electroactivity of all the materials, but especially of Ni81P19 and particularly of matte side of its ribbons, decreasing overpotential at −10 mA cm−2 to −0.14 V. XRD, SEM/EDS and XPS studies were carried out. EIS measurements indicated that the rise of hydrogen evolution after etching was related mainly to the increase of surface area, and only slightly to the rise of intrinsic electroactivity, probably being due to the formation of NiO. It is proposed that etched Ni81P19 might be an efficient cathode for hydrogen production by water electrolysis.

Post Harvest Treatments and Shelf Life of Some Tropical Fruit

Fruits are perishable horticultural crops grown in tropical and sub-tropical areas of the world. It is a richest source of micro nutrients and phyto chemicals that contributed a significant role in human health. Mango, avocado, papaya, guava and pine apple are popular and economically important tropical fruits due to their essential nutritional properties and appreciated eating quality. However, in developing countries, upto 50% of those fruits are lost after harvest due to improper post-harvest handling practices. Edible coating, dip in calcium chloride solution, hot water treatment and drying are easily applicable post harvest treatments used in the preservation of such tropical fruits. Shelf life of mangoes coated using edible coating material can be extended up to 18 days without rotting and developing unpleasant-flavour relative to coated guava, papaya, avocado and pine apple fruits. Dipping harvested fruits in various concentration of calcium chloride solution exhibited different storage life. Consequently, mango fruits treated with 10% of calcium chloride solution preserved for 30 days at 12°C and 85-90% relative humidity. Guava fruits treated by hot water at 45oC for 3 minute lasts upto 31 days under room temperature. In this review maximum shelf life up to 9 months was found for Avocado fruit dried using freeze drying method.

Development of a non-equimolar AlCrCuFeNi high-entropy alloy and its corrosive response to marine environment under different temperatures and chloride concentrations

This work aims to characterize the influence of temperature and chloride solution concentration on the corrosion behavior of a newly developed high-entropy alloy system (Al2Cr5Cu5Fe53Ni35) in a simulated marine environment. A direct correlation was found between temperature and chloride concentration with localized corrosion resistance. The Point Defect Model approach is employed to analyze the influence of the temperature and chloride concentration upon the properties of the passive film formation over the alloy surface in seawater solutions. It turns out that the present system alloy exhibits a better local corrosion resistance than conventional martensitic stainless steel UNS S40300 when temperature is below 60 ∘C in similar electrolytic environment.