Coolant Spray Research Articles

Aluminium rolling: improving production and quality with minimum energy consumption

Improvements in control systems technology and datalogging have allowed improved dynamic control of the factors affecting strip flatness and quality. Modern automatic flatness control systems for aluminium cold and foil mills have the potential to increase productivity and reduce energy consumption significantly. The contribution of coolant spray control to these objectives is summarised.

Quantitative and qualitative analysis of particulate production during simulated clinical orthodontic debonds

Objectives The objectives of this investigation were firstly to quantitatively and qualitatively determine particulate production during orthodontic debond and enamel cleanup procedures, and secondly to examine what methods can be employed to minimize operator exposure to such dust particles. Methods A qualitative study was performed to determine the aerodynamic diameters and compositions of particulates produced during simulated clinical debonds and enamel cleanup procedures on extracted teeth. In each case the enamel was cleaned using tungsten carbide burs in either a high or slow speed handpiece, with or without water coolant spray, with or without high volume evacuation (HVE) or a face mask. Results The use of a high speed handpiece with a tungsten carbide bur and water irrigation at enamel cleanup produced the greatest concentration of respirable particulates. Within this dust, calcium, phosphorus, aluminum and silicon were the most commonly found elements. The dust levels observed did not exceed limits advised for respirable dusts in general. However, the concentration of silica within the dusts created is unknown. The face mask and HVE were effective at reducing exposure to respirable particles, but the mask was most effective, reducing exposure by up to 96%. Significance A face mask is an effective means of reducing dust inhalation and is advised for all clinical procedures that produce dusts.

Mercury sensitisation: review, relevance and a clinical report

Eczematous eruptions may be produced through topical contact with mercury and by systemic absorption in mercury sensitive individuals. Mercury is considered a weak sensitiser and contact with mercury salts such as chloride or ammonium chloride may cause hypersensitivity leading to contact dermatitis or Coomb's Type IV hypersensitivity reactions. The typical manifestation is an urticarial or erythematous rash, and pruritus on the face and flexural aspects of limbs, followed by progression to dermatitis. True allergy to mercury is rare but is more common in females. Exposure to mercury vapour produced in operating rooms is the main concern for dentists. Every effort should be made to avoid contact with mercury vapour if possible by using barrier techniques, reducing the temperature of the operating room and of the amalgam restoration. Air conditioning and proper ventilation of the operating room, the use of coolant sprays, good suction and proper handling of amalgam waste is recommended. Various reports show the use of MELISA (memory lymphocyte immunostimulation assay) and patch tests in determining mercury sensitivity. Topical application of glucocorticoids and dimethisone is helpful.

Mitigation of pain during intravenous catheter placement using a topical skin coolant in the emergency department

Objective:Although intravenous (IV) line placement is a common procedure in the emergency department (ED), it is an uncomfortable experience for many patients. Topical analgesic agents are rarely used because they...

Long-term fatigue control of nuclear power plant piping systems on the basis of in-service measurements

In principle, the stress and fatigue analyses during plant design are based on specked design loads which are classified into different levels (normal operation, upset conditions, etc.). Since the level B conditions, which rarely occur during actual service life, may essentially contribute to the fatigue usage factor, these design predictions are deemed to be pessimistic and conservative. A much more realistic stress and fatigue analysis can be performed on the basis of in-service measurements, which then influences the schedule and scope of the in-service inspections by non-destructive examinations (NDEs). For that purpose, the German nuclear power plants (NPPs) are equipped with in-service monitoring systems. Experience shows that the actual loading of the safety and fatigue relevant systems, for example surge lines, main coolant lines and spray lines, is more complex than assumed during design: temperature stratifications and transient loads vary in their level and combination. In some cases the design loads do not cover these events'; in other cases they are too conservative. This paper presents an approach for long-term fatigue control as used in German NPPs, illustrated by examples for surge and spray lines.

Infiltração marginal em cavidades de classe V restauradas com materiais estéticos, utilizando diferentes técnicas restauradoras

The purpose of this study was to compare the microleakage of class V cavities restored with composite resin (CR), resin-modified glass ionomer cement (RMGIC) and polyacid-modified resin composite (PAMRC), using different clinical procedures. Thirty-six noncarious human molars were used in this study. A class V cavity, measuring approximately 3 mm x 4 mm x 2 mm, was prepared in each tooth in both buccal and lingual aspects, with a diamond bur (number 1,093) at high speed, with coolant water spray. The occlusal margin was located on enamel and the gingival margin was located on dentin. The teeth were divided into 9 groups with 8 specimens each. The cavities were restored according to different techniques. The specimens from groups 1, 2, 4 and 5 did not receive acid etching. The samples were stored in water at 37 degrees C for 24 hours, subjected to occlusal load, thermocycled and immersed in rhodamine B. The restorations were then washed and sectioned in buccolingual direction. The depth of dye penetration was scored from zero (no leakage) to 3 (maximum leakage). The Kruskal-Wallis test revealed statistically significant differences between the materials (p < 0.05). PAMRC used without acid etching showed the greatest score of leakage in both margins. In the gingival margin, CR showed scores of leakage lower than those of PAMRC and RMGIC. Additional retentions and acid etching were able to decrease microleakage in PAMRC restorations in both gingival and occlusal margins.

PERFORMANCE OF HIGH-SPEED DENTAL HANDPIECES SUBJECTED TO SIMULATED CLINICAL USE AND STERILIZATION

The authors investigated the performance of nine commercially available high-speed air-turbine dental handpieces subjected to 1,000 simulated clinical uses and sterilizations. Six new handpieces from each of nine different models were subjected to simulated clinical use with a custom-made handpiece wear tester and then autoclaved. Ten parameters related to clinical performance (longevity, power, turbine speed, fiberoptic transmission, eccentricity, noise, chuck performance, visibility angle, interocclusal clearance and water coolant spray pattern) were measured at baseline and after 250, 500, 750 and 1,000 use/sterilization cycles. Power, turbine speed, eccentricity and noise performance were statistically analyzed using one-way analysis of variance and Turkey post hoc pairwise comparison tests at the .05 significance level. At baseline, significant differences were found between models for all of these parameters. In general, from baseline to 1,000 cycles, the handpieces exhibited greater eccentricity and reduced fiberoptic performance. Longevity data analyzed by using Gehan's generalized Wilcoxon test for comparison of survival distributions (alpha = .05) revealed significant differences between the handpiece models. The results of this study indicate that no handpiece model is superior to the others in all parameters evaluated. All models evaluated can be expected to perform for at least 500 clinical use/sterilizations, or approximately one year, if properly maintained. Clinicians need to be able to identify handpieces that can withstand repeated heat sterilization without loss of performance or longevity. The results of this study will aid clinicians in selecting handpiece models that meet their needs.

Subcutaneous facial emphysema resulting from routine tooth preparation: A clinical report

S u b c u t a n e o u s emphysema is a complication tha t may occur subsequent to denta l extract ion procedures. 1-6 Emphysema of the head and neck may resul t from air-water coolant spray from high-speed air-driven handpieces used for tooth sectioning. 4 Sectioning of a tooth during an extract ion procedure should involve the use of a denta l handpiece in which the air s t ream under pressure is directed away from the field of operation. 2, 4, 5 This makes it possible to avoid the introduct ion of a i r under pressure into subcutaneous spaces of the head and neck during the course of tooth removal. The entry of air into the face is not l imited to tooth extractions, but may also occur through other portals of entry, which include endodontically t rea ted teeth, 1 the periodontium, 7 and lacerat ions of in t raora l soft t issues. 1 This clinical repor t i l lus t ra tes how the or ientat ion of a high-speed denta l handpiece used for a crown prepara t ion made it possible for a i r under pressure to be driven into a lacerat ion in a pat ient ' s buccal mucosa. The unique feature of this occurrence of subcutaneous emphysema is tha t the ent ry of a i r from the mouth into the face occurred as a result of a i r being forced under pressure away from, ins tead of toward the field of operation.

Effects of Nd:YAG laser on the permeability of root canal wall dentin

The effects of a thermally cooled pulsed Nd:YAG laser on the permeability and structural appearance of the root canal wall were investigated in vitro. Twenty specimens of freshly extracted human teeth were prepared by conventional methods. The teeth were randomly divided into two groups. Group 1 teeth were prepared conventionally but not lased. Group 2 specimens received three 15-s laser exposures totaling 45 s duration within the root canal via optical fiber delivery. Laser parameters were set at 5 W, 50 Hz, using a simultaneous air/water coolant spray of 10 psi air and 2 psi water. The external surfaces of the teeth were sealed with acrylic and placed in 2% methylene blue dye for 24 h. The teeth were then sectioned, photographed, and compared under light microscope for the extent of dye penetration. The specimens were subsequently prepared for scanning electron microscopy for correlation of permeability measurements with surface modifications. The combined use of scanning electron microscopy and dye permeability measurements revealed a sealing of the dentinal wall by deposition of glass-like material and, in one specimen, the bridging of a lateral canal that partially occluded the canal. Based on statistical comparisons, permeability of laser-treated teeth was significantly less than untreated specimens (alpha = 0.005).

Evaluation of a commercial stencil/aerosol — Coolant technique for freeze branding horses

SUMMARY A study was conducted to evaluate a commercial stencil/aerosol-coolant freeze branding technique for horses. Forty five (45) mares were branded with one of five treatments to determine which combination of pre-treatment application of alcohol on the brand site, number of coolant spray applications or drying methods produced the most acceptable brands. Reactions indicative of pain were quantitated for all treatments. Kit equipment and recommended procedures were evaluated. Non-alcohol pre-treated digits tended to be more acceptable than alcohol pretreated digits (P .20), number of applications (P >.10) or drying method (P >.12). The stencil/aerosol-coolant technique is safe and convenient, but at least three applications of spray are necessary to produce acceptable brands.

An Application of Advanced Control Theory on Shape Control for Thin Strip Rolling

Shape control on strip rolling is essential for achieving good quality of products, particularly for thin strip. To control the shape, roll gap profile is controlled normally by steering of roll load cylinders, roll bending and coolant sprays. For thickness above 0.2 mm material, sprays effect is smaller . However, for thin strip (foil) below 0.2 mm, control capability of each means becomes different from thicker application, i.e. spray effect is larger and response is quicker. Regarding this phenomenon, two basic strategies should be considered for a shape control system, which are.1)Control references for actuators are calculated to minimize generalized quadratic error between measured shape and target shape considering shape correction effect in dynamic process2)Bang-bang control is found as the quickest spray control, and further, this is more cost effective and maintenance free than the spray flow rate control.Those strategies have been applied successfully on the shape system for aluminumfoil rolling and achieved shape tolerance less than 10 I unit.

Strip Profile Control System for Aluminium Hot Strip Mill

This paper discusses the strip profile control that was carried out at an aluminum hot strip mill. Calculation procedures for setting up the actuators for each stand of the 3-stand finishing mill involving the double chock work roll bender, VC backup roll/ and work roll coolant spray pattern, necessary for achieving the target strip profile without adverse effect on flatness are presented here in this paper. The work roll thermal crown model and strip profile model that are used for the above strip profile setup are also explained. The results of applying this control system tc the hot strip mill in the Fukui works of Furukawa Aluminum Co. Ltd. are also shown.

Thermal Hydraulic Behavior in Upper Plenum during Refill-Reflood Phase of BWR LOCA, (I) CCFL and CCFL Breakdown Phenomena in Upper Plenum

Using Eighteen Degree Sector Test Apparatus (ESTA), which represents in mock-up a BWR pressure vessel in full height from jet pump bottom to standpipe top, has been constructed and refill-reflood phenomena have been studied under LOCA conditions. Specifically, the main concern of this study is to clarify how CCFL and CCFL breakdown phenomena at various flow restricted components affect the refill-reflood phase of a BWR LOCA. The objective of this study is to confirm the conservatism of current safety evaluation models and to present the data base for best estimate code qualification and verification. This paper deals with separate effect tests of CCFL and CCFL breakdown phenomena associated with injection of subcooled water into the upper plenum and clarifies the conditions for which subcooled emergency coolant liquid would cause CCFL breakdown and rapid draining into the fuel bundles. The results demonstrate that injection of subcooled emergency coolant spray causes CCFL breakdown with minimum subcooling...

An Analytical Rolling Model Including Through Thickness Shear Stress Distributions

An extension of the slab method of analysis as applied to rolling is presented. The von Mises yield criterion, including shear stresses, is written in terms of the frictional boundary condition at the roll-metal interface. Utilizing simplifying assumptions, an expression results which can then be combined with the equilibrium equations so that analytical expressions for roll force, torque, and extrusion ratio result. Whereas the concept is based on the same physical principles inherent in Orowan’s analysis of rolling, the slab method of analysis used here is less rigorous but has the advantage that analytic expressions are obtainable. Therefore, the equations are applicable for mill control purposes. Furthermore, the analytic expressions can be inverted so that estimates of friction and flow stress may be obtained by roll force and extrusion ratio measurements. In hot rolling, the temperature of the sheet may then be inferred from this value of flow stress, if the material’s flow stress is a known function of temperature and strain rate. Thus, this provides the capability to eventually control sheet temperatures and lubrication conditions by adjusting coolant sprays. Theoretical verification is discussed by comparison with Orowan’s theory and finite element analysis. Accuracy is discussed in terms of hot continuous mill and laboratory reversing mill data.

The use of coolant sprays to enhance heat demonstrations

The use of coolant sprays to enhance heat demonstrations