Influence Of Ultrasound Treatment Research Articles

The influence of ultrasound treatment on the hydrophobic flocculation of lignite

ABSTRACT Ultrasonic energy has mostly been investigated for the flotation process in coal fines, but its application to agglomeration is extremely limited. Therefore, the effect of ultrasound on the process of hydrophobic flocculation was investigated in this study. In addition, the effect of using ultrasound at the flocculation stage and/or at the pretreatment stage on the combustible matter recovery and the ash content was determined. In this regard, the use of ultrasound at the pretreatment stage improved the hydrophobic flocculation of coal, but the use of ultrasound at the flocculation stage, in other words, the use of ultrasound during the entire process, reduced the recovery of the combustible matter. Also, the power of ultrasound and the time of treatment affected the success of flocculation, and the best values were achieved at a power of 150 watt of ultrasound and a treatment time of 3 min. In addition, the ultrasonic treatment reduced the zeta potential negativity of coal particles. Moreover, ultrasound pretreatment led to higher contact angle values, resulting in more successful flocculation. As a result, coal with an ash content of 26.02% was enriched with an ash content of 10.81% and an efficiency of 78.12 by using ultrasound pretreatment.

Influence of ultrasound treatment on the physicochemical and antioxidant properties of mung bean protein hydrolysate

This study aimed to investigate influence of ultrasonic treatment on physicochemical and antioxidant properties of mung bean protein hydrolysate (MPH). Physicochemical properties of MPH were evaluated by Tricine-SDS-PAGE, particle size distribution, fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy, among others. Radicals scavenging activities of ABTS, hydroxyl, superoxide anion, Fe2+ chelating ability and reducing power characterized antioxidant activities of MPH. MPH contained four bands of 25.6, 12.8, 10.6 and 4.9 kDa, in which 4.9 kDa was the most abundant. Ultrasonic treatment increased the contents of aromatic and hydrophobic amino acids in MPH. Ultrasonic treatment decreased the content of α-helix of MPH and increased β-sheet and β-turn compared to MPH. MPH-546 W (ultrasonic treatment 546 W, 20 min) had the lowest average particle size (290.13 nm), zeta potential (-36.37 mV) and surface hydrophobicity (367.95 A.U.). Antioxidant activities of ultrasonicated-MPH increased with the ultrasonic power, achieving the lowest IC50 (mg/mL) of 0.1087 (ABTS), 1.796 (hydroxyl), 1.003 (superoxide anion) and 0.185 (Fe2+ chelating ability) in 546 W power. These results indicated ultrasonic treatment would be a promising method to improve the antioxidant properties of MPH, which would broaden the application scope of MPH as bioactive components in the food industry.

Mechanical damage and thermal effect induced by ultrasonic treatment in olive leaf tissue. Impact on polyphenols recovery

The influence of ultrasound treatment (US) on cellular damage of olive leaf tissue was studied. Mechanical damage and thermal effect of US were characterized. The level of tissue damage was defined by the diffusivity disintegration index ZD based on the diffusivity of solutes extracted from olive leaves differently treated. The Arrhenius form using the temperature dependences of the thermal treatment time within the temperature interval 20–90 °C was observed for the thermal process. The corresponding activation energy ΔUT was estimated as 57 kJ/mol. The temperature dependences of electrical conductivity were measured for extracts of intact and maximally treated olive leaves. Then the diffusivity disintegration index ZD and total phenolic compounds recovery for three studied US powers were calculated (100, 200, and 400 W). The results evidenced that the mechanically stimulated damage in olive leaf tissue can occur even at a low US power of 100 W if treatment time is long enough (t = 3.5 h). The US treatment noticeably accelerated the diffusion process mechanically in addition to its thermal effect. Trials in aqueous solution revealed the dependence of polyphenols extraction on damage level with respect to the US power applied.

Influence of ultrasound treatment in combination with modified atmosphere on microorganisms and quality attributes of fresh‐cut lettuce

SummaryThe influence of ultrasound (US) treatment in combination with modified atmosphere packaging on microbial loads and quality attributes of fresh‐cut lettuce was investigated during storage at 4 °C for up to 15 days. Fresh‐cut lettuces were sonicated for different durations (0, 5, 10 and 15 min) by US (20 kHz, 226 W cm−2) and then packed in active modified atmosphere packaging (MAP). Results showed that US treatment combined with modified atmosphere effectively inhibited growth of bacteria, mold and yeast during storage. The US treatment for 10 min combined with MAP reduces mass losses and colour change, inhibits POD and PPO activities, conserves ascorbic acid and chlorophyll contents and maintains water distribution in fresh‐cut lettuce. These results illustrated that US treatment combined with modified atmosphere was an effective preservation method to improve storage quality of fresh‐cut lettuce.

Generation of oxygen vacancies in NiFe LDH electrocatalysts by ultrasound for enhancing the activity toward oxygen evolution reaction

Introduction of vacancies is a promising route to enhance the performance of electrocatalysts by tuning the electronic structure and bonding energy. Here, the influence of ultrasound treatment on the O vacancies formation and interlayer spacing in NiFe layered double hydroxide (LDH) was investigated. It is found that the strong ultrasound treatment results in rich O vacancies on the surface of NiFe LDH, which affect the electrocatalysis performance. Besides, the ultrasound treated NiFe LDH electrocatalysts had a reduced thickness with a hexagonal nanosheet morphology and expanded interlayer distance, which could promote the diffusion of reactant and generated gas. When the obtained defect-rich NiFe LDH electrocatalyst prepared by a 10-min ultrasonic treatment was applied to catalyze oxygen evolution reaction (OER), only 194 mV of overpotential was needed to maintain a current density of 10 mA·cm−2.

Influence of ultrasound pretreatment on the subsequent glycation of dietary proteins

The influence of ultrasound treatment on the subsequent glycation process of proteins is controversial. Glycation behaviors of bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and β-casein (β-CN) after ultrasound pretreatment (UP) were compared by both evaluating glycation kinetics and analyzing structural changes of proteins. UP resulted in both unfolding and aggregation behavior in protein samples, which altered the accessibility of the Lys and Arg. Five cycles of UP up-regulated the glycation degree of BSA and β-Lg, possibly due to the unfolding behavior induced by UP, which exposed additional glycation sites. In contrast, 30 cycles of UP induced a dramatic increase (by 97.9nm) in particle size of BSA, thus burying portions of glycation sites and suppressing the glycation process. Notably, UP had minimal influence on glycation kinetics of β-CN, due to its intrinsic disordered structure. Based on proteomics analysis, the preference of Lys and Arg during glycation was found to be changed by UP in BSA and β-Lg. Four, 3 and 3 unique carboxyethylated lysine residues were identified in glycated BSA after 0, 5 and 30 cycles of UP, respectively. This study suggests that the protein glycation can be affected by UP, depending on the ultrasonication duration and native structure of the protein.

Ultrasound treatment to modified atmospheric packaged fresh-cut cucumber: Influence on microbial inhibition and storage quality

Influence of ultrasound treatment on microorganisms and the quality of modified atmospheric packaged fresh-cut cucumber during storage were investigated. Fresh-cut cucumber was treated with ultrasound (US, 20 kHz) in different time (5, 10 and 15 min) and then modified atmospheric packaged as well as stored at 4 °C for 15 d. The results showed that US treatment inhibited the growth of total number of colonies, mold and yeast in modified atmospheric packaged fresh-cut cucumber during storage. US treatment for 10 min effectively reduced the loss of weight, firmness, total soluble solids and total color change (ΔE), the increase of MDA content and the degradation of ascorbic acid content and flavor, as well as decreased water mobility and maintained cell wall integrity in fresh-cut cucumber during storage. Therefore, these results demonstrated that US treatment was helpful for inhibiting microorganisms and improving storage quality, and could be an effective method to enhance the preservative effect of modified atmospheric packaged fresh-cut cucumber.

Brettanomyces population in wine – Influence of ultrasound treatment

Brettanomyces population in wine – Influence of ultrasound treatment

Influence of Ultrasound Treatment on Cavitation Erosion Resistance of AlSi7 Alloy.

Ultrasound treatment of liquid aluminum alloys is known to improve mechanical properties of castings. Aluminum foundry alloys are frequently used for production of parts that undergo severe cavitation erosion phenomena during service. In this paper, the effect of the ultrasound treatment on cavitation erosion resistance of AlSi7 alloy was assessed and compared to that of conventionally cast samples. Cavitation erosion tests were performed according to ASTM G32 standard on as-cast and heat treated castings. The response of the alloy in each condition was investigated by measuring the mass loss as a function of cavitation time and by analyzing the damaged surfaces by means of optical and scanning electron microscope. It was pointed out that the ultrasound treatment increases the cavitation erosion resistance of the alloy, as a consequence of the higher chemical and microstructural homogeneity, the finer grains and primary particles and the refined structure of the eutectic induced by the treatment itself.

Research of influence of ultrasound treatment in various liquid media on the surface microflora of semifinished meat

In order to prevent microbial spoilage, meat and meat products could be treatedusing different types of processing. However, these methods do not ensures sterilization and can cause decrease of nutrition and biological value of food product. In this regardstudying of the innovative methods, that guaranteeing consumers safe and minimally-processed foods, is particularly relevant. The addition of lactic acid bacteria and ultrasound (US) treatment have great potential in this direction.Thesurfacemicroflorainvestigations of semifinished meat products were carried out in order to state the positive influence on their microbiological stability by US treatment in different types of medium. Experiments included the study of antagonistic activity of bacteria strains of the genus Lactobacillus acidophilus(L. acidophilus) in relation to typical microflora representatives of chilled meat semi-finished products. Basing on these experiments the strain 7m13 of L. acidophilus with the highest inhibitory activity was chosen. The lowest inhibitory activity was found for strain 5e. The parameters of ultrasonic treatment was established as follows: installed capacity of the treatment 350 Wt with the exposure time 2 minutes, avoiding undesired denaturation changes of muscle proteins. The handling of check samples included the following variants: control (without treatment); sample 1 – treatment in distilled water; sample 2 – treatment in milk whey; sample 3 – treatment in fermented milk whey. As the result of experiments it was found, that the strain 7m13 of L.acidophilus showed the highest antagonistic activity against used test cultures of bacteria. The quantitative and qualitative composition of the surface microflora of the check samples is not constant; coccal forms are less sensitive for ultrasound treatment in comparison with bacilli and yeast cells. The minimal surface microbial population was shown using the combination of fermented milk whey and ultrasound treatment.

Ultrasound energy to accelerate dye uptake and dye–fiber interaction of reactive dye on knitted cotton fabric at low temperatures

Acoustic cavitation formed due to propagation of ultrasound wave inside a dye bath was successfully used to dye cotton fabric with a reactive dye at lower temperatures. The energy input to the system during sonication was 0.7W/cm2. This was within the energy range that contributes towards forming cavitation during ultra-sonication. The influence of ultrasound treatment on dye particle size and fiber morphology is discussed. Particle size analysis of the dye bath revealed ultra-sonication energy was capable of de-agglomeration of hydrolyzed dye molecules during dyeing. SEM micrograph and AFM topographical image of the fiber surface revealed fiber morphology remains unchanged after the sonication. The study was extended in understanding the contribution of ultrasound method of dyeing towards achieving good color strength on the fabric, compared to the normal heating method of dyeing. Study showed color strength obtained using ultra sound method of dyeing is higher compared to normal heating dyeing. Ultrasound energy was able to achieve the good color strength on cotton fabric at very low temperature such as 30°C, which was approximately 230% more than the color strength achieved in normal heating method of dyeing. This indicates that energy input to the system using ultrasound was capable of acting as an effective alternative method of dyeing knitted cotton fabrics with reactive dye.

The Preparation of Soluble Cellouronic Acid Sodium Salt by 4-Acetamide-TEMPO Mediated Oxidation of Ultrasound-Pretreated Parenchyma Cellulose from Bagasse Pith

Abstract The parenchyma cellulose isolated from bagasse pith was used as an alternative resource for preparation of water-soluble cellouronic acid sodium salt (CAS). The influence of ultrasound treatment on the cellulose was investigated for obtaining CAS by regioselective oxidization using 4-acetamide-TEMPO and NaClO with NaClO2 as a primary oxidant in an aqueous buffer at pH 6.0. The yield, carboxylate content and polymerization degree (DP) of CAS were measured as a function of ultrasonic power, agitating time and cellulose consistency by an orthogonal test. The ultrasound-treated conditions were further improved by discussion of ultrasonic power, the most important factor influencing the yield and DP. An optimized CAS yield of 72.9% with DP value (DPv) of 212 was found when the ultrasonic strength is 550 W, agitating time is 3 h and cellulose consistency is 2.0%. The oxidation reactivity of cellulose was improved by ultrasonic irradiation, whereas no significant changes in crystallinity of cellulose were measured after ultrasonic treatment. Moreover, the ultrasound treatment has a greater effect on yielding CAS from parenchyma cellulose than from bagasse fibrous' one. The CAS was further characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM).

Batch and Semibatch Partial Oxidation of Starch by Hydrogen Peroxide in the Presence of an Iron Tetrasulfophthalocyanine Catalyst: The Effect of Ultrasound and the Catalyst Addition Policy

Oxidized starch is important for paper coating because of its good mechanical and sizing properties. Traditionally, starch oxidation is performed by different heavy metals as catalysts and chlorites or chlorines as oxidizing agents. In this study, an environmentally friendly method was developed, utilizing iron tetrasulfophthalocyanine as a catalyst only in small amounts and hydrogen peroxide as a clean oxidant. It has been previously shown that the method works well, but analysis of the kinetic data as well as catalyst deactivation was difficult because of the semibatch operation mode. In this study, hydrogen peroxide was employed in a batch mode, allowing more simple analysis methods for determining the degree of substitution, starch degradation, and hydrogen peroxide decomposition kinetics. Additionally, the effect of adding the catalyst continuously into the solution, as well as the influence of ultrasound treatment on starch prior to oxidation, was studied. The batch-mode results showed DSCOOH = 0.73 for 100 anhydroglucose units at 52 °C and pH 10, whereas adding the catalyst continuously increased DSCOOH to 1.62. An increased DSCOOH was obtained with the ultrasound-treated starch, which shows that ultrasound is a promising method for enhancing the reaction performance.

Influence of ultrasound treatment and dynamic (in-situ) ultrasound loading on the temperature hysteresis of electrophysical characteristics in irradiated n-Si–Fz

Influence of ultrasound treatment and dynamic (in-situ) ultrasound loading on the temperature hysteresis of electrophysical characteristics in irradiated n-Si–Fz

Influence of Ultrasound Treatment on Assembling Structures and Properties of Supramolecular Hydrogels Formed from 1,3,5-Benzenetricarboxylic Acid and 4-Hydroxypyridine

Abstract A new gelator synthesized from 1,3,5-benzenetricarboxylic acid (BTA) and 4-hydroxypyridine (PHP) was capable of gelling water under different ultrasound power. The resulting gels were investigated by gel-to-sol dissociation temperature (Tgel), SEM, DSC, and rheology measurement, which showed that the assembling structures and gel properties were correlated to the ultrasound power.

Characteristics of silicon p–n junction formed by ion implantation with in situ ultrasound treatment

The forming peculiarities of electrically active impurities (B, As, Sb) in silicon with in situ ultrasound (US) excitation have been investigated. The US excitation influences significantly on the redistribution of defects generated by ion implantation. It is shown that there is the possibility of controlling the p–n junction parameters by varying the frequency and intensity of US excitation. The changing of p–n junction parameters is caused by the influence of the US treatment due to interaction of Si structural defects with implanted impurity. The changing of both the quantity of defects and impurities redistribution are realized with the activation annealing that follows implantation. The influence of US treatment on Si shallow p–n junction parameters has been studied in detail. It is shown that the use of US defect engineering is perspective at forming high-quality Si p–n junctions.

Influence of ultrasound treatment on accessibility and regioselective oxidation reactivity of cellulose

Cellulose fibers were treated with ultrasound in order to improve the accessibility and the reactivity of cellulose. The influence of ultrasound treatment on changes of morphology structure, accessibility and oxidation reactivity of cellulose with sodium periodate were discussed. The results revealed an increase in cellulose’s accessibility in terms of water retention value (WRV) with increasing ultrasound treatment time, corresponding to 73.0%, 75.6%, 80.8%, 98.7% and 119.0% after treated for 0, 90, 180, 360 and 720 s, respectively. Furthermore, the regioselective oxidation reactivity of cellulose with sodium periodate was also successfully improved by the ultrasound treatment. However, no significant changes in crystallinity of cellulose were noted after ultrasound treatment. The oxidized products dialdehyde cellulose (DAC) was further characterized by means of FTIR, X-ray diffraction and SEM.