Identification of the Radiative Parameters-Albedo and Optical Thickness-Of the Juncus maritimus Fiber.

The present work aims to characterize the radiative thermal properties albedo and optical thickness of Juncus maritimus fibers using a FTIR spectrometer. Measurements of normal/directional transmittance and normal and hemispherical reflectance are performed. The numerical determination of the radiative properties is conducted through the computational treatment of the Radiative Transfer Equation (RTE) using the Discrete Ordinate Method (DOM), together with the inverse method, which is done through Gauss linearization. As it is a non-linear system, iterative calculations are necessary, which demand a significant computational cost, and, to optimize this problem, the Neumann method is used for the numerical determination of the parameters. These radiative properties are useful to quantify the radiative effective conductivity.

Thermal Variation During Osteotomy With Different Dental Implant Drills: A Standardized Study in Bovine Ribs.

INTRODUCTION: This study evaluated thermal variation (heat generation) by dental drills of similar geometries, made from different materials, during performance of 450 standardized osteotomies in bovine ribs to simulate implant site preparations. MATERIALS AND METHODS: Each of the 3 groups-steel with a diamond-like carbon coating (SG), experimentally surface-treated steel (EG), and aluminum-toughened zirconium ceramic (ZG)-included 3 drills, distributed across 6 subgroups. An implant motor provided torque, rotation, and irrigation for 50% of subgroups. RESULTS: In preparations drilled to 5 mm under irrigation, the number of osteotomies, material, and diameter did not influence thermal variation (ΔT); when drilling to 13 mm, the greatest ΔT occurred in EG (2.8°C). When drilling to 5 mm without irrigation, drill material influenced mean temperature; when drilling to 13 mm without irrigation, the greatest ΔT (5.5°C) occurred in EG. The highest temperature was observed in SG (79.6°C). CONCLUSION: After 50 uses, the greatest ΔT occurred in EG and the ∅3.0-mm drill exhibited the highest mean and peak temperatures. Temperatures were influenced by irrigation, number of uses, depth, drill diameter, geometry, and material; however, mean values were within physiological limits.

Thermal change in a resin block during motorized and manual implant placement.

STATEMENT OF PROBLEM: Several studies have demonstrated the harmful role of heat generation during implant site drilling in subsequent bone healing. However, heat generation during implant placement should also be carefully considered. PURPOSE: The purpose of this in vitro study was to evaluate thermal change in a resin block during motorized and manual implant placement with and without saline irrigation. MATERIAL AND METHODS: Thermocouple probes were placed in resin blocks to measure the thermal change during forty 3.75x15-mm self-tapping cylindrical screw implant placements as follows: MtI group, 10 motorized implant placements with external saline irrigation; MtNI group, 10 motorized implant placements without irrigation; MI group, 10 manual implant placements with external saline irrigation; MNI group, 10 manual implant placements without irrigation. The temperature values were recorded with a data acquisition system with a 20-channel multiplexer module connected to a personal computer. The normality of data distribution was assessed with the Shapiro-Wilk test and the homogeneity of variances with the Levene test. The mean temperatures of the groups was assessed with the 3-way ANOVA test followed by the Tukey HSD test for normal distribution and the Games-Howell test for non-normal distribution (α=.05). RESULTS: The rate of temperature rise in the resin blocks was 1.1°C to 7.3°C. The highest mean temperature was present in the group for manual implant placement without irrigation (26.2 ±1.1°C), and the lowest thermal change was in the motorized implant placement group with external saline irrigation (23.6 ±1.0°C). CONCLUSIONS: The thermal change in resin blocks during motorized implant placement was lower than manual implant placement, especially with external saline irrigation.

Mechanical model for simulating the conditioning of air in the respiratory tract.

OBJECTIVE: To create a mechanical model that could be regulated to simulate the conditioning of inspired and expired air with the same normal values of temperature, pressure, and relative humidity as those of the respiratory system of a healthy young man on mechanical ventilation. METHODS: Using several types of materials, a mechanical device was built and regulated using normal values of vital capacity, tidal volume, maximal inspiratory pressure, positive end-expiratory pressure, and gas temperature in the system. The device was submitted to mechanical ventilation for a period of 29.8 min. The changes in the temperature of the air circulating in the system were recorded every two seconds. RESULTS: The statistical analysis of the data collected revealed that the device was approximately as efficient in the conditioning of air as is the respiratory system of a human being. CONCLUSION: By the study endpoint, we had developed a mechanical device capable of simulating the conditioning of air in the respiratory tract. The device mimics the conditions of temperature, pressure, and relative humidity seen in the respiratory system of healthy individuals.

Modelo mecânico para simulação do condicionamento pulmonar do ar respirado / Mechanical model for simulating the conditioning of air in the respiratory tract

OBJETIVO: A criação de um modelo mecânico que pudesse ser regulado para simular o condicionamento do ar inspirado e expirado nos mesmos valores normais de temperatura, pressão e umidade relativa do aparelho respiratório de um homem jovem hígido sob ventilação mecânica. MÉTODOS: Utilizando-se diversos tipos de materiais, um aparelho mecânico foi construído e regulado com valores normais de capacidade vital, volume corrente, pressão inspiratória máxima, pressão expiratória final positiva e temperatura do gás dentro do sistema. O aparelho foi submetido a ventilação mecânica por um período de 29,8 min. A cada dois segundos, foram registradas as alterações de temperatura do ar circulado no sistema. RESULTADOS: Mediante análise estatística dos dados coletados observou-se que o aparelho construído foi eficiente no condicionamento do ar aproximadamente nos moldes do aparelho respiratório de um ser humano. CONCLUSÃO: Ao final deste estudo, conseguiu-se desenvolver um aparelho mecânico capaz de simular o condicionamento do ar respirado nas mesmas condições de temperatura, pressão e umidade do aparelho respiratório de um ser humano hígido.

OBJECTIVE: To create a mechanical model that could be regulated to simulate the conditioning of inspired and expired air with the same normal values of temperature, pressure, and relative humidity as those of the respiratory system of a healthy young man on mechanical ventilation. METHODS: Using several types of materials, a mechanical device was built and regulated using normal values of vital capacity, tidal volume, maximal inspiratory pressure, positive end-expiratory pressure, and gas temperature in the system. The device was submitted to mechanical ventilation for a period of 29.8 min. The changes in the temperature of the air circulating in the system were recorded every two seconds. RESULTS: The statistical analysis of the data collected revealed that the device was approximately as efficient in the conditioning of air as is the respiratory system of a human being. CONCLUSION: By the study endpoint, we had developed a mechanical device capable of simulating the conditioning of air in the respiratory tract. The device mimics the conditions of temperature, pressure, and relative humidity seen in the respiratory system of healthy individuals.