• Restorative Dentistry and Endodontics
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• v.44 no.1
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• pp.3.1-3.10
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• 2019

Objectives: It was the aim of this study to evaluate the effect of cooling water temperature on the temperature changes in the pulp chamber and at the handpiece head during high-speed tooth preparation using an electric handpiece. Materials and Methods: Twenty-eight intact human molars received a standardized occlusal preparation for 60 seconds using a diamond bur in an electric handpiece, and one of four treatments were applied that varied in the temperature of cooling water applied (control, with no cooling water, $10^{\circ}C$, $23^{\circ}C$, and $35^{\circ}C$). The temperature changes in the pulp chamber and at the handpiece head were recorded using K-type thermocouples connected to a digital thermometer. Results: The average temperature changes within the pulp chamber and at the handpiece head during preparation increased substantially when no cooling water was applied ($6.8^{\circ}C$ and $11.0^{\circ}C$, respectively), but decreased significantly when cooling water was added. The most substantial drop in temperature occurred with $10^{\circ}C$ water ($-16.3^{\circ}C$ and $-10.2^{\circ}C$), but reductions were also seen at $23^{\circ}C$ ($-8.6^{\circ}C$ and $-4.9^{\circ}C$). With $35^{\circ}C$ cooling water, temperatures increased slightly, but still remained lower than the no cooling water group ($1.6^{\circ}C$ and $6.7^{\circ}C$). Conclusions: The temperature changes in the pulp chamber and at the handpiece head were above harmful thresholds when tooth preparation was performed without cooling water. However, cooling water of all temperatures prevented harmful critical temperature changes even though water at $35^{\circ}C$ raised temperatures slightly above baseline.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.137-151
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• 1994

In order to evaluate objectively the anxiety level in dental treatment, the author used Biotrainer(BF-120R), one of the skin temperature biofeedback apparatus, to examine 68 dental outpatients on their digital skin temperature change due to routine consecutive dental procedures(oral examination, anesthetic injection, cavity preparation, fissure sealing, polishing). The subjective anxiety level change was also evaluated by visual analog scale. The obtained results were as follows : 1. The skin temperature decreased through consecutive procedures and the temperature in each procedure decreased until 60sec, and then increased on 120sec. 2. The temperature changes in Preparation and Injection were greater than those in other procedures. 3. Generally, male exhibited more change of skin temperature in all procedures than female. 4. Type II, continuously decreasing after procedure, occupied the most in all patients and yhad the lowest beseline temperature. 5. The anxiety level of before-procedure was higher than that of after-procedure and the levels in Injection and Preparation were higher than in other procedures.

• Applied Microscopy
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• v.45 no.4
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• pp.218-224
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• 2015

A technical overview on the various sample preparation methods for electron backscattered diffraction (EBSD) analysis is carried out. The mechanical polishing with colloidal silica finish, electro-chemical polishing, dual layer coating and ion beam milling are introduced for the common sample preparation methods for EBSD observation and some issues that are frequently neglected by the common EBSD users but should be considered to get a reliable EBSD data are discussed. This overview would be especially helpful to the people who know what EBSD technique is but do not get a reliable EBSD data because of difficulties in sample preparation.

• Korean journal of food and cookery science
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• v.2 no.2
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• pp.76-83
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• 1986

Time and temperature, pH and Aw, and microbiological evaluation were made to identify critical control points during various phases in product flow of chicken soup preparation in a university foodservice establishment. The results are summarised as follows: 1) Time and temperature data indicated that the phases of cooling after cooking, post-preparation, and holding ingredients at room temperature before assembly were critical. 2) pH and Aw values were in favorable for microbial growth. 3) Microbiological data indicated that the phases of basic ingredients. post-preparation and holding ingredients before assembly were critical. 4) Critical control points identified were; basic ingredients, cooling after cooking, post-preparation, holding before assembly and service, and assembly and service. 5) Several guidelines were suggested for the effective qualitly control program.

• Journal of the Korean Dietetic Association
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• v.19 no.3
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• pp.236-252
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• 2013

The purpose of this study was to assess the microbiological quality of home-delivered meals during production and delivery for children from low-income families. Production flows from a facility in Seoul that provides home-delivered meals were analyzed and the time-temperature of the food was measured. Microbiological assessment was performed for the production environment, personal hygiene, and food samples at each production and delivery step based on the process approach. It took 2 hours or longer from completion of production to meal delivery. An aerobic colony count (ACC) and coliform were not detected at knives, cutting boards, and dish towels. However, ACC (at pre-preparation, preparation, and packing areas) and coliform (at the preparation area) were detected on the hands and gloves of employees. Air-borne bacterial counts varied according to day and preparation area (ND~6 CFU/plate/15 min). Food temperatures, on the completion of production and meal delivery, fell into temperature danger zones. ACC and coliform counts of raw ingredients did not decrease after pre-preparation (washing and sanitizing) for menus involving food preparation with no cook step. ACC decreased after cooking step for menus of food preparation with cook step, but the ACC of the stir-fried and seasoned dried filefish fillet on the completion of cooking was too numerous to count due to improper heating. The ACC of seasoned young Chinese cabbages (a menu with complex food preparation) increased during delivery (from 2.5 log CFU/ml to 5.0 log CFU/ml). This qualitative assessment of foodborne pathogens revealed that B. cereus was detected in vegetable and meat product menus. These results suggest time-temperature control is necessary during production and delivery and management guidelines during production of home-delivered meals are provided for safe production.

• Journal of the Korean institute of surface engineering
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• v.27 no.3
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• pp.134-142
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• 1994

$Al_2O_3$coatings on mild steel substrate by plasma spray process were produced to evaluate microstructural characterization and mechanical properties. As-coated $Al_2O_3$coating samplessd were subjected to two heat treat-ment conditions : ⅰ) annealing under vacuum circumstance, ⅱ) hot press treated condition. The two heat treat-ed coatings were investigated in terms of microhardness, adhesion strength, wear resistance, porosity forma-tion, and microstructures. In the case of the coatings which were subject to preparation step ⅰ, the porosity in the coating was decreased with the increase of temperature ($700^{\circ}C$-$1100^{\circ}C$), and the wear resistance, microhardnesss and adhesion strength were increased with the increase of temperature. On the other hand, in the case of the coatings which were subject to preparation step ⅱ, wear resistance and adhesion strength were improved with the increase of temperature and pressure. Experimental measurements of coatings which were produced by both preparation conditions were enhanced compare to those of as-coated coatings.

• Steel and Composite Structures
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• v.32 no.5
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• pp.559-569
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• 2019

The bond strength between composite laminates and concrete is a key factor that controls the behavior of concrete members strengthened with fiber reinforced polymer (FRP) sheets, which can be affected by several parameters such as thermal stresses and surface preparation. This article presents the result of an experimental study on the bond strength between FRP sheets and concrete at ambient temperature after specimens had been exposed to elevated temperatures of up to $200^{\circ}C$. For this purpose, 30 specimens of plain concrete with dimensions of $150{\times}150{\times}350mm$ were prepared. Three different conventional surface preparation methods (sandblasting, wire brushing and hole drilling) were considered and compared with a new efficient method (fiber implantation). Deformation field during each experiment was monitored using particle image velocimetry. The results showed that, the specimens which were prepared by conventional surface preparation methods, preserved their bond integrity when exposed to temperature below glass transition temperature of epoxy resin (about $60^{\circ}C$). Beyond this temperature, the bond strength and stiffness decreased significantly (about 50%) in comparison with control specimens. However, the specimens prepared by the proposed method displayed higher bond strengths of up to 32% and 90% at $25^{\circ}C$ and $200^{\circ}C$, respectively.

• Particle and aerosol research
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• v.5 no.3
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• pp.95-109
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• 2009

A low temperature plasma process has been widely used for semiconductor fabrication and can also be applied for the preparation of solar cell, MEMS or NEMS, but they are notorious in the point of particle contamination. The nano-sized particles can be generated in the low temperature plasma process and they can induce several serious defects on the performance and quality of microelectronic devices and also on the cost of final products. For the preparation of high quality thin films of high efficiency by the low temperature plasma process, it is desirable to increase the deposition rate of thin films with reducing the particle contamination in the plasmas. In this paper, we introduced the studies on the generation and growth of nanoparticles in the low temperature plasmas and tried to introduce the recent interesting studies on nanoparticle generation in the plasma reactors.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.99-110
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• 1990

Time and temperature, microbiological quality of sauteed beef or pork were assessed in five general hospital foodservice operations. The microbiological quality of basic ingredients was poor and strict temperature control of refrigeration was required during delivery, and storage after receiving. In pre-preparation and cooking phases, improper handling practices of employees such as reusage of wiping cloth, indiscreet use of cutting board, and food handling with contaminated hands were noticed. During cooking phase, internal temperature of sauteed beef or pork reached a temperature of $74^{\circ}C$ or higher and the microbiological quality was good in general except hospital A. In all but hospital B, cooked foods were held at too high temperature in humid kitchen environment where could have permitted considerable bacterial multiplication. The sanitary conditions of container, equipments, and supplies were poor and should be improved promptly. The critical control points identified were: Hospital A: basic ingredients, pre-preparation, cooking, and preservice holding; Hospical B: bll8ic ingredients, and pre-preparation; Hospital C: basic ingredients, pre-preparation, pre service holding, and service; Hospital D: basic ingredients, pre-preparation, preservice holding, and service; and Hospital E: basic ingredients, pre-preparation, pre service holding, and service.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.123-135
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• 1992

Time and temperature conditions, and microbiological qualities of six categories of menu items were assessed according to the process of food product Row in a 500 bed general hospital. The Harzard Analysis Critical Control Point (HACCP) system was applied to determine harzards, to assess their severity and risks, and to identity CCPs and memos for monitoring mem. The Critical Control Points identified for each category of menu items were: Meat Soup (Kyung Sang Do Gogi Guk): Pre-preparation, holding after pre-preration, and holding after cooking; Pot Stewed Stuffed Cabbage (Soe Yangbaechu Mali Chim): pre-preparation, holding after Pre-preparation, stuffing, cooking and holding after cooking; Boned Pork Sour Salad (Doeji Suyuk Muchim): Pre-preparation, holding after pre-preparation, and post-preparation after cooking; Sauteed Pork Ball (Jeyuk Wanja Jon): pre-preparation, holding after pre-preparation, shaping, and holding after cooking; Stir-fried Fragrant Mushroom (Pyogo Bosot Bokkum): basic ingredients, Pre-preparation, holding after pre-preparation, and holding after cooking; and Fried Corn with Vegetables (Oksusu Yachae Tuigim): pre-preparation, holding after pre-preparation, mixing, and holding after cooking.