Increasing Power Settings Research Articles

Aircraft engine particulate matter emissions from sustainable aviation fuels: Results from ground-based measurements during the NASA/DLR campaign ECLIF2/ND-MAX

The use of alternative jet fuels by commercial aviation has increased substantially in recent years. Beside the reduction of carbon dioxide emission, the use of sustainable aviation fuels (SAF) may have a positive impact on the reduction of particulate emissions. This study summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany. Two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) were burned in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic content and the corresponding fuel hydrogen content on non-volatile particle number and mass emissions. Reductions up to 70% in non-volatile particle mass emission compared to the fossil reference fuel were observed at low power settings. The reduction trends to decrease with increasing power settings. The fuels showed a decrease in particle emission with increasing fuel hydrogen content. Consequently, a second fossil fuel with similar hydrogen content as one of the HEFA blends featured similar reduction factors in particle mass and number. Changes in the fuel naphthalene content had significant impact on the particle number emission. A comparison to in-flight emission data shows similar trends at cruise altitudes. The measurements highlight the importance of individual fuel components in regulating engine emissions, particularly at the low thrust settings typically employed during ground operations (e.g. during idle and taxi). Therefore, when selecting and mixing SAF blends to meet present fuel-certification standards, attention should be paid to minimizing complex aromatic content to achieve the greatest possible air quality and climate benefits.

Technical application of a ternary alternative jet fuel blend – Chemical characterization and impact on jet engine particle emission

The use of alternative fuels is an essential element in future aviation. There are currently different approaches with regard to fuel production processes and feedstock materials. This requires flexible handling of available fuel quantities. The production of fuel mixtures (blends) is inevitable for an effective usage of commercially available fuel components. Within the framework of the project DEMO-SPK approx. 600 t of a ternary mixture (multiblend) of alternative jet fuels was produced and used in a real airport infrastructure at the airport Leipzig/Halle. Production and application were accompanied by extensive R&D activities to show that on-spec, semi-synthetic multiblends can be produced from several different synthetic fuels. One important aspect is the emission of soot particles from aircraft engines. The Multiblend Jet A-1 has been analyzed in a flow reactor setup regarding the formation of soot precursor compounds in comparison to a reference Jet A-1. The experiment revealed a lower formation of relevant soot precursors which also corresponds to the higher hydrogen content of the Multiblend Jet A-1 compared to the reference fuel. The lower soot formation in a real aircraft engine has been proven during ground runs of an A300-600 aircraft with PW4158 engines. The Multiblend Jet A-1 showed lower particle number and particle mass emission than the reference fuel. The difference to the reference fuel decreased with increasing power settings. In summary, the emission of particle mass is reduced by ~ 29 % and the number of emitted particles is reduced by ~ 37 % if the ICAO landing-and-take-off cycle is used for evaluation.

Influence of battery power setting on carbonyl emissions from electronic cigarettes.

INTRODUCTIONAlthough e-cigarettes share common features such as power units, heating elements and e-liquids, the variability in design and possibility for customization represent potential risks for consumers. A main health concern is the exposure to carbonyl compounds, which are formed from the main components of e-liquids, propylene glycol and glycerol, through thermal decomposition. Levels of carbonyl emissions in e-cigarette aerosols depend, amongst others, on the power supplied to the coil. Thus, e-cigarettes with adjustable power outputs might lead to high exposures to carbonyls if the users increase the power output excessively. The aim of this work was to elucidate the generation of carbonyls in relation to undue battery power setting.METHODSCarbonyl emissions were generated by two modular e-cigarettes equipped with two atomizers containing coils of different resistance following the ISO 20768:2018 method. The battery power output was increased from the lower wattage level to above the power range recommended by the producer. Carbonyls were trapped by a 2,4-dinitrophenylhydrazine (DNPH) solution and analysed by LC-MS/MS.RESULTSThe amount of carbonyl emissions increased with increasing power setting. An exponential incline was observed when the applied power level exceeded the recommended power range. Exceeding the recommended power range by just 5 watts resulted in up to twenty times the amount of carbonyls emitted at the recommended upper power level. Generation of acetaldehyde and acrolein next to other carbonyls was prominent at high power outputs.CONCLUSIONSE-cigarettes with customisable power setting might generate high amounts of carbonyls if the battery power output is set by the consumer to levels above the recommended range. This represents a high risk of exposure to carbonyls and thus should be avoided by integrating safety features in e-cigarette devices to limit the possible power settings to the range specified by the manufacturer.

Optimal ablation volumes are achieved at submaximal power settings in a 2.45-GHz microwave ablation system.

Local ablative therapies, including microwave ablation (MWA), are common treatment modalities for in situ tumor destruction. Currently, 2.45-GHz ablation systems are gaining prominence because of the shorter application times required. The aims of this study were to determine optimal power and time to ablation volume (AbV) ratios for a new 1.8-mm-2.45-GHz antenna using ex vivo tissue models. The 1.8-mm-2.45-GHz Accu2i MWA system was employed to perform ablations in bovine liver, porcine muscle, and porcine kidney ex vivo. Whole tissues were prewarmed (35°C) and multiple ablations performed at power settings of 60 to 180 W for 2- to 6-minute time intervals. Postablation, tissues were dissected, AbVs calculated, and correlations to power and time settings made. Significant increases in AbV were measured between each of the time points for a constant power setting in all 3 tissues. Increasing power settings led to significant increases in AbV at power settings ≤140 W. However, no significant increase in AbV was obtained at power settings >140 W. Optimal efficiency for MWA using a new 1.8-mm-2.45-GHz system is achieved at settings of ≤140 W for 6 minutes in a range of ex vivo tissue and no additional benefit occurs by increasing the power setting to 180 W in these tissues.

Fine and ultrafine particle emissions from microwave popcorn

This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter < 100nm) emissions from microwave popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9×10(10) to 8.0×10(10) No./min for total particle number and from 134 to 249μg/min for PM2.5 .

Irrigant Flow beyond the Insertion Depth of an Ultrasonically Oscillating File in Straight and Curved Root Canals: Visualization and Cleaning Efficacy

IntroductionThe purpose of this study was to evaluate the influence of the insertion depth of an ultrasonically oscillating file on the ability to remove dentin debris from simulated canal irregularities in an extracted tooth model of a straight root canal and its influence on the flow of irrigant in both straight and curved canals. MethodsA tooth model with artificial depressions in 1 canal wall at 0.5, 2, 4, and 6 mm from the working length was used. Ultrasonic-activated irrigation was performed with the file inserted 1, 2, 3, 4, or 5 mm short of the working length. Dye penetration and high-speed recordings of the flow in straight and curved canals showed the static and dynamic behavior of the flow during ultrasonic activation. ResultsThe overall cleaning efficacy decreased with increasing distance between the file and the apex, with the depressions next to the file and within 3 mm in front of the file being the cleanest. The flow observed from the visualization experiments matched this distance, suggesting a direct relation between flow and cleaning. The observed flow depth increased with increasing power setting; the curvature of the root canal had no influence on the flow depth. High-speed imaging showed a start-up phase with deeper fluid activation than in the steady phase afterward. ConclusionsThe ultrasonically oscillating file could remove dentin debris up to 3 mm in front of the file tip, coinciding with the extent of the observed flow. The root canal curvature had no influence on the irrigant flow.

Evaluation of mineral content of dentin prepared by erbium, chromium:yttrium scandium gallium garnet laser

Laser etching has an effect on the mineral content of dentin. The aim of this study was to evaluate the mineral content of dentin prepared at three different power settings with an erbium, chromium:yttrium scandium gallium garnet (Er,Cr:YSGG) laser. The enamel of five, lower, wisdom, molar teeth was removed to expose the dentin surface. Four dentin slabs were obtained, then each tooth was randomly divided into four portions (groups 1 W, 2 W, 3 W and control) so that we could evaluate the effect of laser treatment. The Er,Cr:YSGG laser used for the study had a pulse duration of 140 micros, a pulse repetition rate of 20 Hz and a power output range of 0 W to 6 W. Laser energy was delivered through a fiberoptic system to a sapphire tip terminal 6 mm long and 600 microm in diameter, using a non-contact mode. The levels of five elements: magnesium (Mg), phosphorus (P), calcium (Ca), potassium (K), and sodium (Na), in each slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). There were significant differences between the groups (1 W, 2 W, 3 W and control) for Ca, Mg, Na, P and Ca/P ratio (P<0.05); however, there were no significant differences for K (P=0.43). Laser treatment at 1 W significantly affected the mean percentage weight of all element groups except K. Scanning electron microscopy (SEM) photographs indicated that the surface irregularities increased with increasing power setting.

Performance of Ultrasonic Retrograde Systems

The aim of this study was to evaluate variations in power output of different Piezon-Master 400 (Electro Medical Systems, Nyon, Switzerland) ultrasonically driven generators and analytic handpieces at a range of power settings. A scanning laser vibrometer was used to measure the maximum vibration displacement amplitude of a KiS 2D tip. Ten repeat scans were made of the unloaded tip oscillation at six power settings. Data were acquired from four different generators and handpieces. Linear trend lines fitted to all tip data showed that none of the generator/handpiece combinations produced a linear increase in tip displacement amplitude with increasing power setting. A univariate analysis of variance (general linear model) showed that generator, handpiece, and power were all significant variables (p<0.0001). This study showed that there is significant variability in the power output between generators, and not all Analytic handpieces performed consistently when compared with each other.

Argon Plasma Coagulation with or without Saline Immersion: Comparative In Vivo Study on Tissue Effects

Background: Isolated reports suggest that argon plasma coagulation (APC) under saline immersion can deliver energy more evenly to a larger area and in a more superficial manner with less risk of perforation. This manner of application has been used in the rectum and bladder. Our aim was to study the effects of APC with saline immersion in vivo compared to conventional APC application in the stomach and at different power settings. Material and Methods: Two 40-45 kg female domestic pigs were used. An ICC 300 machine and end firing probe (ERBE, Marietta, GA) were utilized. APC was endoscopically performed in the gastric antrum at fixed distance from the mucosa with increasing energy levels in regular (R) fashion and under saline immersion (I), in parallel rows. Three to four rows were made for each group in each animal, so that 6-7 samples could be analyzed. The animals were sacrificed immediately after and the treated areas were excised. Diameter was measured with a micrometer and the tissue was then fixed in formalin for histologic study. Depth of thermal injury was established histologically (in relation to wall layer). Depth and diameter were compared between both groups. Results: average diameter (table below; values = mm) was greater in the R group and increased with increasing power settings. Depth was not statistically different between groups at any power setting. A thermal mucosal effect was evident starting at 15 W in both groups. Submucosal injury was identified at 90 W only in the R group. Histologically, the mucosal thermal damage was attenuated along the borders in some samples from the I group. Macroscopically a white uniform coagulum with an erythematous rim was evident along the margins in the I group in contrast to a charred coagulum seen in the R group. Conclusions: These results do not support the theoretical tissue effects from APC performed under saline immersion. APC performed under saline immersion does not appear to have any advantages for clinical use.

Subthreshold Transpupillary Thermotherapy Reduces Experimental Choroidal Neovascularization in the Mouse without Collateral Damage to the Neural Retina

Transpupillary thermotherapy (TTT) is currently being evaluated for treatment of choroidal neovascularization (CNV) in age-related macular degeneration. To optimize TTT for CNV, the effect was analyzed of invisible (subthreshold) or visible (threshold) doses of TTT on the normal mouse retina and on experimental CNV. TTT was delivered to the normal retina of 42 mice with a diode laser at increasing power settings (50, 60, 70, or 80 mW), to obtain thermal lesions ranging from invisible (subthreshold) to visible (threshold) burns. CNV was induced in 53 mice by krypton laser photocoagulation of the fundus, after which the CNV lesions were treated with TTT (50, 60, or 80 mW). Eyes were enucleated 7 days after TTT and prepared for histology, and the CNV complex was evaluated on hematoxylin-eosin stained serial sections by measuring the maximum height of the CNV lesions. Ultrastructural changes were examined by transmission electron microscopy. Increasing the TTT laser power yielded gradually more visible effects. At 50 mW, which induced subthreshold burns, no damage was seen in the neural retina, retinal pigment epithelium (RPE), or choroid at any time point. By contrast, eyes treated with higher power exhibited progressively more damage to the neural retina, including a complete disruption of the outer nuclear layer. When TTT was applied to the laser-induced CNV lesions, the height of lesions was significantly reduced (P < 0.001) in response to all three power settings at 7 days after treatment. The mean relative thickness of the CNV lesion was 3.29 +/- 0.89 in untreated mice, whereas in TTT-treated mice it was 1.69 +/- 0.35, 1.69 +/- 0.41 and 1.70 +/- 0.17 at power settings of 50, 60, and 80 mW, respectively. The overlying neural retina showed no apparent damage with the 50- or 60-mW settings, whereas outer nuclear layer disruption occurred with a power of 80 mW. Electron microscopy confirmed the presence of vascular occlusion at 1 day and a fibrotic scar at 7 days after TTT. Subthreshold TTT can effectively occlude newly formed vessels and cause regression of the experimental CNV complex without damaging the neural retina. The results demonstrate the importance of using subthreshold laser power in experimental and clinical evaluation of TTT.

A new insight into the oscillation characteristics of endosonic files used in dentistry

The aim of this study was to assess the oscillation characteristics of unconstrained endosonic files using a scanning laser vibrometer (SLV). Factors investigated included file vibration frequency and node/antinode location as well as the variation in file displacement amplitude due to increasing generator power setting. A 30 kHz Mini Piezon generator (Electro-Medical Systems, Switzerland) was used in conjunction with a #15 and #35 K-file. Each file was fixed in position with the long axis of the file perpendicular to the SLV camera head. The laser from the SLV was scanned over the length of the oscillating file for generator power settings 1 to 5 (minimum to half power). Measurements were repeated ten times. The fundamental vibration frequency for both files was 27.50 kHz. Scans of each file showed the positions of nodes/anti-nodes along the file length. The #15 file demonstrated no significant variation in its mean maximum displacement amplitude with increasing generator power, except at power setting 5, where a decrease in displacement amplitude was observed. The #35 file showed a general increase in mean maximum displacement amplitude with increasing power setting, except at power setting 4 where a 65% decrease in displacement amplitude occurred. In conclusion, scanning laser vibrometry is an effective method for assessing endosonic file vibration characteristics. The SLV was able to demonstrate that (unloaded) file vibration displacement amplitude does not increase linearly with increasing generator power. Further work is being performed on a greater variety of files and generators. Vibration characteristics of files under various loads and varying degrees of constraint should also be investigated.

2003 Spring Scientific Meeting of the British Endodontic Society

Aim To evaluate the variability in power output between Piezon‐Master 400 generators (EMS) with different Analytic handpieces (Analytic). The displacement amplitude of an unloaded KiS 2D (Obtura Spartan) root end preparation tip was measured using a Scanning Laser Vibrometer (SLV; Polytec) over a range of generator power settings.Methodology Four Piezon‐Master 400 ultrasound generators were each used in conjunction with four analytic handpieces. A graduated scale was positioned over the power dial of each of the ultrasound generators to enable incremental power settings to be selected (six settings were used between the minimum and the 9 o'clock position). The handpiece with a KiS 2D tip was fixed in position so that the anterior surface of the tip was vertical and perpendicular to the scanner head of an SLV. Previous investigation showed that the maximum displacement amplitude of the oscillating tip occurred at the unconstrained end. The laser from the SLV was therefore scanned over this point to assess the maximum displacement amplitude. Scans were repeated 10 times for each power setting. The whole process was then repeated for all generator/handpiece combinations. Throughout the investigation, irrigation was used at a constant flow rate of 20 mL min−1.Results Linear trend lines fitted to all tip data showed that none of the generator/handpiece combinations produced a linear increase in tip displacement amplitude with increasing power setting. A univariate analysis of variance (general linear model) showed that generator, handpiece and power were all significant variables (P &lt; 0.0001). Multiple post hoc comparisons (Tukey's test) at a significance level of P &lt; 0.05 (dependent variable being displacement amplitude) showed that all generators were significantly different from each other (P &lt; 0.0001), except generators 1 and 3 that showed no significant differences (P &gt; 0.66). No significant differences were found between handpieces 1 and 4 (P &gt; 0.98) and handpieces 2 and 3 (P &gt; 0.82). All other handpieces were significantly different from each other (P &lt; 0.0001).Conclusions This study demonstrated that, for all Piezon‐Master 400 generators and handpieces tested, there was no linear increase in tip displacement amplitude with increasing generator power setting. It was also shown that there is considerable variability in power output between commercially available Piezon‐Master 400 ultrasound generators and different analytic handpieces. Users should be aware of this variability, which may influence clinical practice. Further investigation using tips under load is required.

Ultrasonic scaler tip performance under various load conditions.

The aim of this investigation was to assess the effect of loading on ultrasonic scaler tip displacement amplitude, using a scanning laser vibrometer. Four generators were selected for this investigation including: Cavitron Select (Dentsply), Cavitron SPS (Dentsply), Piezon Master 400 (EMS) and Mini Piezon (EMS). The insert designs used with these generators included the TFI-10 and TFI-3 (with the Dentsply generators) and P-tip (with the EMS generators). The insert tips were contacted against tooth surfaces with loads of 0.25, 0.5 and 1.0 N. The scanning laser vibrometer was then used to scan the vibrating scalers at various generator power settings. The tips generally showed an increase in displacement amplitude with increasing power setting, although this increase was often nonlinear. Displacement amplitudes of like tips were generally found to be significantly different from each other at all loads. For individual inserts, loading caused a significant difference in tip response from the unloaded situation and also between loads. This investigation has demonstrated that there is a high variability associated with dental ultrasonic scaler inserts. Clinicians and researchers should be aware of this variability as it may affect both clinical procedures and future research.

The tissue effect of argon plasma coagulation on esophageal and gastric mucosa

Background: Argon plasma coagulation is a diathermy-based non-contact therapeutic endoscopic modality that may have a lower risk of perforation than other tissue ablation techniques. Methods: Its effect was studied on three fresh esophageal and three fresh gastric resection specimens using power settings from 40 to 99 Watts at 90 degrees, with 1 mm separation using pulse durations of 1 and 3 seconds. A scoring system for depth of tissue damage was created and samples were analyzed blindly by a gastrointestinal histopathologist. Results: There was significantly greater damage to gastric tissue using a 3-second (compared with 1-second) pulse (p = 0.003) and marginally significantly greater damage to esophageal tissue using the 3-second pulse (p = 0.053). Tissue damage was related to power setting for gastric (p = 0.031) but not for esophageal tissue (p = 0.065). Only 1 of 42 esophageal samples and 2 of 42 gastric samples examined showed damage extending into the muscularis propria. Conclusions: Deep tissue damage that could lead to perforation was rare with argon plasma coagulation. The depth of gastric mucosal damage increased with increased pulse duration and increasing power settings, and, although the depth of esophageal mucosal damage was marginally related to pulse duration, it was not related to the power setting. (Gastrointest Endosc 2000;52:342–5).

A dual passive cavitation detector for localized detection of lithotripsy-induced cavitation in vitro.

A passive cavitation detector (PCD) identifies cavitation events by sensing acoustic emissions generated by the collapse of bubbles. In this work, a dual passive cavitation detector (dual PCD), consisting of a pair of orthogonal confocal receivers, is described for use in shock wave lithotripsy. Cavitation events are detected by both receivers and can be localized to within 5 mm by the nature of the small intersecting volume of the focal areas of the two receivers in association with a coincidence detection algorithm. A calibration technique, based on the impulse response of the transducer, was employed to estimate radiated pressures at collapse near the bubble. Results are presented for the in vitro cavitation fields of both a clinical and a research electrohydraulic lithotripter. The measured lifetime of the primary growth-and-collapse of the cavitation bubbles increased from 180 to 420 microseconds as the power setting was increased from 12 to 24 kV. The measured lifetime compared well with calculations based on the Gilmore-Akulichev formulation for bubble dynamics. The radiated acoustic pressure 10 mm from the collapsing cavitation bubble was measured to vary from 4 to 16 MPa with increasing power setting; although the trends agreed with calculations, the predicted values were four times larger than measured values. The axial length of the cavitation field correlated well with the 6-dB region of the acoustic field. However, the width of the cavitation field (10 mm) was significantly narrower than the acoustic field (25 mm) as bubbles appeared to be drawn to the acoustic axis during the collapse. The dual PCD also detected signals from "rebounds," secondary and tertiary growth-and-collapse cycles. The measured rebound time did not agree with calculations from the single-bubble model. The rebounds could be fitted to a Rayleigh collapse model by considering the entire bubble cloud as an effective single bubble. The results from the dual PCD agreed well with images from high-speed photography. The results indicate that single-bubble theory is sufficient to model lithotripsy cavitation dynamics up to time of the main collapse, but that upon collapse bubble cloud dynamics becomes important.

Holmium:YAG lithotripsy for large renal and bladder calculi: strategies for efficient lithotripsy.

Holmium:YAG lithotripsy is effective for all stone compositions, and high success rates may be expected. Large renal and bladder calculi may be treated effectively with Ho:YAG lasertripsy. Using angled optical fibers and increasing power settings may be particularly useful to increase lithotripsy speed.

Electrophysical factors influencing endoscopic sphincterotomy

Background: Analog computer techniques were used to measure electrosurgical power during sphincterotomy in experimental models and patients. Methods: Total energy and transient changes in power were measured during sphincterotomy of bile ducts in the livers of pigs, ampullae of humans post mortem, and during clinical sphincterotomy. The effect of waveform on hemostasis was studied in experiments on canine mesenteric arteries. Results: Electrosurgical waveforms (CUT, COAG, BLEND) were measured. Halving wire contact length halved energy needed to initiate cutting. The CUT waveform rarely initiated cutting at lower power settings than the BLEND waveform. With CUT, BLEND, and COAG waveforms, approximately the same energy initiated cutting. Efficiency of cutting increased linearly with power. The COAG waveform required higher power settings than BLEND or CUT to initiate cutting ( p < 0.05). Force and wire diameter influenced cutting. BLEND was more effectively hemostatic than CUT ( p < 0.05). COAG was significantly more hemostatic than BLEND and CUT. Cutting efficiency during clinical sphincterotomy was poor. Conclusions: This work has practical implications. Shortening wire contact length was effective in starting a cut at suboptimal settings, whereas changing from BLEND to CUT made little difference. Increasing power setting may help if cutting does not start. BLEND stops bleeding better than CUT. COAG stops bleeding better than BLEND but cuts poorly. Cutting during clinical sphincterotomy is inefficient and can be improved. (Gastrointest Endosc 1998;47:43-52.)

Dental hard tissue cutting characteristics of an ultrasonic drill

Ultrasonic instruments are used in clinical dentistry to perform a variety of tasks. Several designs of instrument are commercially available, which operate at ultrasonic frequencies of 20–42kHz. They may be used for various purposes such as removal of hard deposits from tooth surfaces, cleansing root canals, and more recently preparation of cavities in tooth tissue during surgical procedures. The aim of this study was to investigate the clinical effectiveness of a working ultrasonic instrument designed for surgical use (Neosonic, Amadent Corp, Cherry Hill, N.J. U.S.A.). The instrument is supplied with stainless steel cutting tips that facilitate cavity preparation in hard tooth tissue. Three designs of tip, designated CT1-3 were chosen for this study. The tips were calibrated by measuring their oscillation displacement amplitudes in air, using light microscopy over increasing power settings. Extracted teeth were sectioned and polished to produce a smooth dentine surface. The instrument was applied to the dentine surfaces for 1 minute across the same power range at a load of approximately 20g which was representative of clinical loading. The prepared specimens were scanned with a Form Talysurf and the depth of the resulting grooves measured (n=6 for each power setting). Results showed that for all tip designs an increase in power setting resulted in increased displacement amplitude and cutting ability. This increase was linear, with minimal cutting occurring at lower power settings.