Ultrasonic Unit Research Articles

Ultrasonic scaling in COVID‐era dentistry: A quantitative assessment of aerosol spread during simulated and clinical ultrasonic scaling procedures

ObjectiveHealthcare agencies recommend limited use of aerosol‐generating procedures to mitigate disease (COVID‐19) transmission. However, total dispersion patterns of aerosols, particularly respirable droplets, via dental ultrasonic units is unclear. The purpose of this study was to characterize and map total spatter, droplet and aerosol dispersion during ultrasonic scaling in simulated and clinical contexts.MethodsUltrasonic scaling was performed on dental simulation units using methylene blue dye‐stained water. All resultant stain profiles were photoanalysed to calculate droplet size and travel distance/direction. Airborne particle concentrations were also documented 0–1.2 m (0–4ft.) and 1.2–2.4 m (4–8ft.) from patients during in vivo ultrasonic scaling with a saliva ejector.ResultsStain profiles showed droplets between 25 and 50µm in diameter were most common, with smaller droplets closer to the mouth. In‐vivo particle concentrations were uniformly low. The smallest (<1 µm, PM1) and largest (>10 µm, PM10+) particles were most common, especially within 1.2 m (4ft.) of the patient. Respirable particles (PM2.5) were uncommon.ConclusionsTests showed the highest concentration of small droplets in zones nearest the patient. While uncommon, particles were detected up to 2.4 m (8ft.) away. Furthermore, observed particle sizes were consistent with those that can carry infectious agents. Efforts to mitigate the spread of inhalable aerosols should emphasize proximate regions nearest the procedure, including personal protective equipment and the use of evacuation devices.

MODERNIZATION OF THE QUALITY SYSTEM IN THE PRODUCTION OF ROUND ROLLED PRODUCTS ON THE SMALL-GRADE MILL 250

The paper suggests ways to modernize the quality system in the production of long products in the conditions of PAO Severstal. The issues of optimizing the operation of the adjustage section are considered. The aim of the work was to develop proposals for the implementation of measures that allow us to produce more competitive products. Activities include the installation of finishing equipment and quality control at the adjustage. During the modernization of the mill 250 adjustage, it is proposed to install a production line for finishing and quality control of finished products, including an automatic ultrasonic control unit, a correct machine with oblique rollers, a roughing and grinding unit and cold cutting shears. The equipment and warehouses of the workshop are located in such a way that there is no intersection of cargo flows. The main equipment of the mill is located in one span with a width of 36 m and a length of 435 m. Between the mills 250 and 350 there is a storage area, measuring 162 × 168 m. On the available free areas of the auxiliary section, it is possible to place equipment for the following operations: detection of defects using a flaw detector, straightening on the correct machine with skewed rollers, continuous abrasive stripping on a roughing and grinding unit. The capacity of the mill in this case is 76 t/h, which is the maximum of the entire range. The modernization of the product quality system will increase the profit, increase the profitability of products by 34% by improving the quality. At the small-grade mill 250, it will be possible to produce products that are more competitive in the metal market compared to those currently produced, and this will allow us to reach new consumers of products.

Evolutionary Leap in Endodontics. Case report

The Leap protocol combines the newest and most active association of reciprocal-rotary instrumentation, aluminum insert ultrasonic, and diode laser. The reciprocal-rotary technique consists of Niti instruments used in different motions depending on the stage of the treatment and promotes the balanced cutting effectiveness and reduced risk of fracture files. Moreover, it creates a centered and tapered shape. The aluminum tip for the ultrasonic unit delivers agitation, emulsification, and cavitation of antiseptic solutions that improve the cleaning. The dye and laser use cause the ablation and final disinfection. This paper describes the case of a patient with asymptomatic apical periodontitis in an upper first right molar submitted to endodontic treatment performed with Leap protocol. After conventional procedures, the root canals were prepared by using reciprocal-rotary instrumentation techniques. Between each file a new solution was placed and activated with the ultrasonic handpiece. At the end of instrumentation, the root canals were aspirated, dried with paper points, the indocyanine dye was placed into the root canals and, DaVinci laser was used for 30 seconds. The gutta-percha cones matching the final Niti file were used coated with AH Plus sealer. A periapical radiograph was taken to verify obturation and its anatomical complexity. Six months after the procedure, the patient was asymptomatic, and the radiographic examination showed healthy periradicular tissues. It is concluded that the use of Leap protocol in conventional endodontic treatment was effective, suggesting that this therapy may provide additional benefits to patients when compared to the conventional technique.

Acoustic cavitation at low gas pressures in PZT-based ultrasonic systems

The generation of cavitation-free radicals through evanescent electric field and bulk-streaming was reported when micro-volumes of a liquid were subjected to 10 MHz surface acoustic waves (SAW) on a piezoelectric substrate [Rezk et al., J. Phys. Chem. Lett. 2020, 11, 4655–4661; Rezk et al., Adv. Sci. 2021, 8, 2001983]. In the current study, we have tested a similar hypothesis with PZT-based ultrasonic units (760 kHz and 2 MHz) with varying dissolved gas concentrations, by sonochemiluminescence measurement and iodide dosimetry, to correlate radical generation with dissolved gas concentrations. The dissolved gas concentration was adjusted by controlling the over-head gas pressure. Our study reveals that there is a strong correlation between sonochemical activity and dissolved gas concentration, with negligible sonochemical activity at near-vacuum conditions. We therefore conclude that radical generation is dominated by acoustic cavitation in conventional PZT-based ultrasonic reactors, regardless of the excitation frequency.

A System for Detection of Locusts Swarms in Farms using IoT

Agriculture is an indispensable part of the Indian economy. It forms a significant share of our domestic revenue and a source of livelihood for many. An attack on the farm by any noxious living being would therefore have a rather unfavourable impact on the crop as well as the financial aspects of the farmer. In this paper we present as solution through image processing and ultrasonic sensors to solve this grave matter so as to prevent any further damage in the near future. The system suggested here will repel these noxious living beings withoput causing deaths and thus maintaining a balance in the ecosystem. The system will work in real time and the two units i.e. the image processing unit and the ultrasonic unit will communicate through internet of things (IoT).

Ультразвуковая интенсификация удаления сероводорода из мазута

The article considers the problem of environmental pollution caused by the presence of hydrogen sulfide in fuel oil. Hydrogen sulfide has a negative impact on the human health: a slight degree of poisoning develops within 3-4 hours already at a 100 mg/m3 concentration of hydrogen sulfide in the air. The regulatory documents limit the hydrogen sulfide content in fuel oil. The search for new available methods of cleaning fuel oil from hydrogen sulfide is relevant today. There has been considered one of the alternative methods of hydrogen sulfide removal from fuel oil, namely, ultrasonic treatment. The method allows changing the dispersed composition of fuel oil and intensifying the extraction of the gas phase of hydrogen sulfide. The advantages of ultrasonic treatment include the absence of injected reagents and environmental cleanliness, small size, low energy costs and the possibility of using ultrasound unit at existing refineries due to its compactness. The influence of the ultrasonic unit capacity and flow rate on hydrogen sulfide removal from fuel oil and change of its dispersion composition has been studied. There have been presented the optimal conditions for ultrasonic treatment and described the mechanism of hydrogen sulfide removal by using ultrasonic treatment

Estimation of the stability of skeletal muscle myoglobin of chilled pork treated with brine activated by low-frequency high-intensity ultrasound

We studied the effect of ultrasonic activation of brine (3%) during salting on the degree of stability of colour parameters of pork with normal (NOR) and abnormal course of autolysis in the CIE Lab colour space. The mechanism of stabilisation of the colour of meat is attributed to donor–acceptor bonds of metmyoglobin (MetMb). The accumulation of excessive number of free electrons in the medium are capable of activating MetMb. This reduces the activity of meat, when the native participants of the metmyoglobin reductase system and their own antioxidant systems of meat are depleted.Based on the additive calculation of deviations (increase / decrease) by the coordinates L*, a*, b* in the CIE Lab system, and the total colour difference (ΔE) in control and experimental samples, recommendations were developed. To optimize the colour characteristics of all types of meat, both on the surface and in the thickness of the meat, the preliminary activation of a 3% brine in a low-frequency submersible ultrasonic unit is recommended. Moreover, preliminary cavitation activation of a 3% is more preferable to stabilise the colour of PSE – meat (pale, soft, exudative (watery),) brine in a flow-through installation.

Comparative Evaluation of Efficacy of Chlorhexidine and Herbal Mouthwash as a Preprocedural Rinse in Reducing Dental Aerosols: A Microbiological Study

Objective. The risk to dentists, assistants, and patients of infectious diseases through aerosols has long been recognized. The aim of this study was to evaluate and compare the efficacy of commercially available preprocedural mouth rinses containing 0.2% chlorhexidine (CHX) gluconate, Befresh™ herbal mouthwash, and water in reducing the levels of viable bacteria in aerosols. Materials &amp; Methods. This was a single-center, double-masked, placebo-controlled, randomized, three-group parallel design study. 30 patients (10 patients in each group) were recruited in the study. Patient rinsed mouth with 10 ml of CHX, 10 ml Befresh™, or 10 ml water. All the patients underwent supragingival ultrasonic scaling for a minimum of 30 min. The aerosol collection was done using a blood agar plate. The blood agar plates were kept approximately 12 inches from the patient’s mouth. The microbial culture was analyzed. The colony-forming unit (CFU) counting in all three groups was assessed using one-way ANOVA test to compare among the groups (p value &lt;0.001). The intergroup comparison was done using the post hoc Tukey test. Result. There was a marked reduction in the CFU in the CHX group in all three areas. This was followed by Befresh™ (Sagar Pharmaceuticals) mouthwash. There was no reduction in the CFU of the water group. Conclusion. This study proves that a regular preprocedural mouth rinse could significantly reduce the majority bacteria present in aerosols generated by the use of an ultrasonic unit, and Befresh™ mouth rinse was found to be equally effective in reducing the aerosol contamination to 0.2% CHX gluconate.

Efficacy evaluation of a cordless ultrasonic unit in achieving reduction of bacterial load within a root canal system as compared to a conventional ultrasonic unit and negative pressure irrigation

IntroductionIncrease in efficacy during root canal irrigation may contribute to better treatment outcomes. This study investigated the efficacy of ultrasonic and negative pressure irrigation systems using sodium hypochlorite (NaOCl) in the reduction of bacterial load in human teeth.One hundred thirty-one single-rooted teeth were cleaned and shaped, autoclaved, and incubated with E. faecalis. Teeth were randomly assigned to three experimental groups (n = 40) and treated in the presence of 1% sodium hypochlorite using EndoUltra cordless ultrasonic, conventional ultrasonic, and Endovac negative pressure irrigation. Syringe irrigation controls were treated with 1% sodium hypochlorite and phosphate-buffered saline via side-vented needle irrigation. All groups with NaOCl received 5% sodium thiosulfate neutralization for 5 min after treatment. Samples of root canal fluid and dentin chips were acquired from canals before and after treatment, incubated on BHI agar, and colony forming units categorized according to quantity. Wilcoxon rank-sum and Bonferroni tests were used for statistical analysis. p values less than 0.05 were considered significant.ResultsEndovac group was significantly better in eliminating bacteria from the root canals than 1% NaOCl (p = 0.006) and PBS syringe irrigation (p = 0.015). However, it was not significantly different from the two ultrasonic groups (p > 0.05). Both ultrasonic groups showed better performance than 1% NaOCl and PBS syringe irrigation, however, not statistically significant (p < 0.03). There was no significant difference between the two ultrasonic devices (p > 0.05).ConclusionEndoVac may be an important tool for bacterial load reduction in oval canals.

Study on the Possibility of Improving the Environmental Performance of Diesel Engine Using Carbon Nanotubes as a Petroleum Diesel Fuel Additive

The relevance of this article is due to the need for improving indicators of exhaust gas toxicity of diesel engines. One of the modern directions of achieving the required environmental performance of diesel engines is the addition of various nanomaterials to petroleum diesel fuel. The aim of the present study was to investigate the possibility of improving the environmental performance of a diesel engine for a generator set using carbon nanotubes as an additive to petroleum diesel fuel in an amount of up to 500 mg/L. Experimental studies were carried out on a D-243 diesel engine operating in a wide range of loads from idle to full load with the addition of 125, 250, and 500 mg/L of carbon nanotubes in the diesel fuel. The mixing of petroleum diesel fuel with nanotubes was done using an ultrasonic unit. The possibility of improving the environmental performance of the studied diesel engine fueled with carbon nanotube-blended petroleum diesel fuel was examined. Results showed that, in the full-load mode of diesel operation, the addition of 500 mg/L of carbon nanotubes to diesel fuel enabled the engine to reduce exhaust smoke from 26.0% to 11.2% on the Hartridge scale.

Investigating vibration characteristics of magnetostrictive transducers for air-coupled ultrasonic NDT of composites

In this study, high-power ultrasonics has been used for non-contact nondestructive testing of composites. Air-coupled magnetostrictive ultrasonic transducers provide reasonable amplitudes of horn oscillations even if this type of ultrasonic stimulation is close to the idle mode. Four types of ultrasonic horns have been designed and manufactured in order to choose an optimal horn configuration. For each horn, the dependence of vibration amplitude on ultrasonic unit power has been found to exhibit a good match between the theoretical and experimental results. The resonance frequencies and amplitudes of oscillatory velocity were experimentally evaluated by using the technique of scanning laser vibrometry and modeled by means of the Autodesk Inventor software. An air-coupled magnetostrictive transducer, in conjunction with an optimized horn, has been used in the evaluation of impact damage in a graphite epoxy composite and detection of water and excessive epoxy adhesive in an aviation honeycomb panel. It is expected that the technique of air-coupled ultrasonics may be useful for inspecting thin, fragile and hydrophilic materials.

STUDY OF THE PHYSICOMECHANICAL PROPERTIES OF 08Kh18N10T STAINLESS STEEL PIPES EXPOSED TO ULTRASOUND UPON DRAWING

The drawing of pipes exposed to ultrasonic vibrations of radial type and their effect on the physical and mechanical properties of the pipe, as well as on the surface quality is studied. The ultrasonic unit with radial vibrations tested under production conditions is used to study the effect of ultrasound on the residual stresses present after drawing, surface roughness, as well as on the physical and mechanical properties and microdefects of 08Kh18N10T steel pipes. Defects and residual stresses before and after drawing under the effect of ultrasound were analyzed by the method of magnetic memory, using the stress concentration meter TSC-4M-16 with an eight-channel scanning device with four two-component sensors (Type 15). It is shown that the residual stresses decreased by more than two times under the effect of ultrasound. The surface roughness after drawing with ultrasound ranged within Ra = 0.087 - 0.092 µm. The physicomechanical properties were studied in tensile tests on an Instron tensile testing machine (SATEC Series). The yield stress qt was 551, the tensile strength qin — 672 MPa. It is shown that the effect of ultra-sound upon drawing pipes made of 08X18H10T stainless steel enhance their quality through reduction of the surface roughness and improved physicomechanical properties.

Digital technologies for providing the quality of food products

The Internet of Things (IoT) conception in food industry is actively developing and covers a wide range of tasks: increasing the quality, elaboration of resources-saving technologies, managing working time and production in real-time mode and revealing failures in manufacturing chains. A method of intensification of the industrial process of baking fish molded goods of increased nutritional value by applying an ultrasonic unit is presented in the article; research data on organoleptic and microbiological quality points, chemical composition and energy value, mineral elements are also reported here. High-mineralized fish rows are safe after ultrasonic treatment and they have excellent organoleptic quality indicators. Using ultrasonic equipment with temperature elements will allow not only to intensify the technological process of baking fish rows, to save their original qualitative characteristics but also to control temperature in the center of the product. Applying ultrasonic will also allow finishing complete repeatable processes in the minimum amount of time and reducing processing costs. Using ultrasonic sensors on packaging will help consumers to control the quality in the process of storing.

Single-Shot Waterless Low-Profile Photoacoustic System: Near-Field Volumetric Imaging In Vivo for Blood Vessels Based on Capacitive Micromachined Ultrasonic Transducer (CMUT).

Intensive research on photoacoustics (PA) for imaging of the living human body, including the skin, vessels, and tumors, has recently been conducted. We propose a PA measurement system based on a capacitive micromachined ultrasonic transducer (CMUT) with waterless coupling, short measurement time (<1 s), backward light irradiation, and a low-profile ultrasonic receiver unit (<1 cm). We fabricate a 64-element CMUT ring array with 6.2 mm diameter and 10.4 MHz center frequency in air, and 100% yield and uniform element response. To validate the PA tissue characterization, we employ pencil lead and red ink as solid and liquid models, respectively, and a living body to target moles and vessels. The system implements a near-field imaging system consisting of a 6 mm polydimethylsiloxane (PDMS) matching layer between the object and CMUT, which has a 3.7 MHz center frequency in PDMS. Experiments were performed in a waterless contact on the PDMS and the laser was irradiated with a 1 cm diameter. The experimental results show the feasibility of this near-field PA imaging system for position and depth detection of skin, mole, vessel cells, etc. Therefore, a system applicable to a low-profile compact biomedical device is presented.

SPECTROPHOTOMETRIC DETERMINATION OF PHENOL COMPOUNDS FROM HERBS OF CORNFLOWER BLUE

There was studied one- and three-fold solid-liquid extraction of natural phenolic compounds (NPC) (in terms of rutin and tannin) from various morphological parts of blue cornflower (Centaurea cyanus L.) on an ultrasonic device created in the research laboratory of the design bureau of the ISS (Voronezh). The optimal time of solid-liquid extraction at the ultrasonic unit has been determined, taking into account wetting and swelling of vegetable raw materials. The quantitative content of NPC (in terms of rutin and tannin) as a percentage of the total content in raw materials at the first stage is about 60%, at the second stage is 25%, and the third one is 18%. It was established that with threefold extraction, the yield of NPC from medicinal plant raw materials increases at the average of 8–10% compared with a one-time extraction. There is offered an improved technique of solid-liquid extraction on the ultrasound unit and UV spectrophotometric determination of NPC from different morphological parts of the blue cornflower. The technique is characterized by the absence of a systematic error, and the relative error at a confidence level of 0.95 does not exceed 5%. The duration of the analysis, taking into account the stage of wetting and osmotic swelling, triple extraction on the ultrasound unit and UV spectrophotometric determination of rutin and tannin in water-ethanol extracts is 40–45 minutes.

Comparative evaluation of the chlorhexidine and cinnamon extract as ultrasonic coolant for reduction of bacterial load in dental aerosols.

Background:Ultrasonic instruments generate aerosols with significantly greater number of bacteria. Preprocedural mouthrinses or chemotherapeutic coolants are used for the reduction of bacterial load in dental aerosols. The use of chlorhexidine as an ultrasonic coolant has been well established. However, this application has not yet been investigated for cinnamon extract which is known to have antibacterial and anti-inflammatory properties in vivo.Aim:The aim of this study is to compare and evaluate the efficacy of chlorhexidine and cinnamon extract as an ultrasonic coolant in reduction of aerosol contamination and biofilm formation during ultrasonic scaling in comparison with the distilled water (DW).Materials and Methods:Sixty patients diagnosed with moderate-to-severe gingivitis were randomly divided into three groups of twenty patients each undergoing ultrasonic scaling. For Group I, chlorhexidine was used as an ultrasonic coolant; for Group II, cinnamon extract was used; and Group III was served as control where DW was used. The aerosols from ultrasonic units were collected on two blood agar plates at three different positions. Both the plates from each position were incubated aerobically for 48 h. The total number of colony-forming units were counted as mean ± standard deviation and statistically analyzed. In addition, biofilm sampling of dental unit waterlines (DUWLs) was also done to evaluate the effect of these antimicrobials. Apart from microbial examination, clinical parameters such as plaque index and gingival index were also evaluated at baseline and 1-month follow-up.Results:Chlorhexidine and cinnamon both were equally effective (P > 0.05) in reducing the bacterial count in aerosols and biofilm in DUWL as compared to DW when used as ultrasonic cooling agent.Conclusion:Both cinnamon and chlorhexidine used as an ultrasonic device coolant through DUWLs effectively helped in the reduction of bacterial count in dental aerosols.

An Herbal Alternative to Control Nosocomial Pathogens in Aerosols and Splatter During Ultrasonic Scaling

Objective: To evaluate the efficacy of herbal mouthwash (Himalaya Hiora Regular) against methicillin-resistant Staphylococcus aureus and Acinetobacter baumanni during ultrasonic scaling. Material and Methods: Group B (n=25) received herbal mouthwash and Group A (n=25) received 0.12% chlorhexidine mouthwash respectively as a preprocedural rinse. The aerosols produced by the ultrasonic unit were collected on MeReSa and Leeds Acinetobacter Agar plates. The experimental setting included eight different locations covering all areas of the operatory. The plates exposed to aerosols for a period of 30 minutes were incubated aerobically at 37 o C for 48hrs and the colony forming units (CFU) were statistically analyzed. Results: Herbal mouthwash (Himalaya Hiora Regular) showed a significant reduction in mean CFU of MRSA compared to 0.12% chlorhexidine. While herbal mouthwash was on par with 0.12% chlorhexidine in the reduction of A. baumannii . Conclusion: Herbal mouthwash was found to be more effective against MRSA than 0.12% Chlorhexidine mouthwash as a pre-procedural rinse. Both herbal mouthwash and chlorhexidine mouthwash was found to be effective against A. baumannii . Herbal mouthwash may be a safe alternative to chlorhexidine against nosocomial pathogens like MRSA and A. baumannii .

Study on the hydrogen induced cracking of API-X80 steels by using 3-axis controlled ultrasonic inspection unit

Three-axis controlled ultrasonic inspection unit is designed and applied to study hydrogen induced cracks (HIC) of hot rolled API-X80 steels non-destructively. The average grain size of the API-X80 is about 1.88 μm with a preferred orientation. (110) poles are preferentially oriented to normal direction (ND), (100) poles are oriented from normal direction to transverse direction (TD) for 30° and from transverse direction to rolling direction (RD) for 45°. (211) poles are oriented to transverse direction for 35°. Micro-cracks are clearly observed by the 3-axis controlled ultrasonic unit for the specimen immersed in the standard HIC solution for 24 h. Diffusive hydrogen content of the API X-80 steel after immersing for 24 h is 3.40 ± 0.03 wtppm, which dramatically increase about 160 and 170% by 4–6% pre-stain, respectively. The initiation of the HIC related to coarse inclusions like silicon and aluminum oxides.

The effect of wool staple length on the mineral content using the same sheep feeding regime

The wool of sheep is suitable to test the mineral supply; however, a number of factors could affect the results. The growth rate and length of staple can be very different according to season, physiological state and individual variation. These factors are likely to affect the quantity of minerals accumulated into the wool. Therefore, the purpose of this research was to examine whether there is a difference between the mineral content of wool nearly reached the full staple length and the freshly grown wool using the same feeding regime.10 Tsigai pregnant sheep have been selected randomly from the same farm. Wool samples were obtained from the withers, side and quarter with bended scissors. Samples were mineralized using nitric acid and hydrogen peroxide using ultrasonic cleaning unit. P, Ca, Mg, Na, S, Cu,Se and Zn content were determined by ICP-OES. Statistical analyses were carried out by SAS (SAS Institute Inc., Cary, NC) GLM procedure.Differences between means were tested by Tukey test. Significantly lower Ca, Na, P, Zn values were found in case of intensively grown wool. Sampling location did not affect the mineral content. Herd mineral supply was adequate. Our results suggest that intensively grown wool samples have to be used for mineral analyses.

Design and Fabrication of a High Power Piezoelectric Ultrasonic Surgery Unit for Dental Implantation

Design and Fabrication of a High Power Piezoelectric Ultrasonic Surgery Unit for Dental Implantation