Study the Passivation Characteristics of Microwave Annealing Applied to APALD Deposited Al2O3 Thin Film

In this study, a self-developed atmospheric pressure atomic layer deposition (APALD) system is used to deposit Al2O3 passivation film, along with the use of precursor combinations of Al(CH3)3/H2O to improve its passivation characteristics through a short-time microwave post-annealing process. Comparing the unannealed and microwave-annealed samples whose temperature is controlled at 200–500 °C, APALD non-vacuum deposited film can be realized with a higher film deposition rate, which is beneficial for increasing the production throughput while at the same time reducing the operating cost of vacuum equipment at hand. Since the microwave has a greater penetration depth during the process, the resultant thermal energy provided can be spread out evenly to the entire wafer, thereby achieving the effect of rapid annealing. The film thickness is subsequently analyzed by TEM, whereas the chemical composition is verified by EDS and XPS. The negative fixed charge and interface trap density are analyzed by the C-V measurement method. Finally, the three major indicators of τeff, SRV, and IVoc are analyzed by QSSPC to duly verify the excellent passivation performance.

Mass spectrometric study of the leak tightness of products made of technical sintered beryllium

Beryllium products exhibiting a low level of absorption of the radiation energy are widely used in scientific instrumentation design (x-ray technology, radiation detectors, etc.). We present the results of studying the leak tightness of products (disks, plates) made of technical sintered beryllium of standard purity and foil obtained by «warm» rolling from high-purity beryllium. The relevant standards and requirements for testing are given. The leak tightness control was performed using mass spectrometric helium leak detectors with forevacuum backing pumps (oil and dry diaphragm pumps) and specialized vacuum equipment. The parameters of tightness of samples made of technical sintered beryllium were determined. The level of the helium signal during blowing was (0.6 – 7.4) × 10–11 Pa · m3/sec, which corresponds to the tightness standard of foreign analogues and matches the requirements of domestic manufacturers of x-ray equipment. The data spread tended to increase due to the growth of the background value. The obtained results can be used to improve high-tech equipment intended for flaw detection, medical devices, rapid analysis of ore raw materials, radiation safety equipment, etc.

A Novel Specimen Produced by Additive Manufacturing for Pure Plane Strain Fatigue Crack Growth Studies

Fatigue crack growth is usually studied using C(T) or M(T) specimens with through-thickness cracks. The objective of the present study is to propose a cylindrical specimen with central crack, produced by additive manufacturing. This geometry allows to have pure plane strain state along the whole crack front, avoiding the complexities associated with corner points, crack shape, and variation of crack closure along crack front. Additionally, this geometry may be used to develop studies in vacuum, avoiding expensive vacuum equipment, since the air is not in contact with the crack front. Cylindrical specimens of Ti6Al4V titanium alloy were produced by Selective Laser Melting and tested at a stress ratio R = 0. Marking with overloads was the solution adopted to measure the length of the internal cracks. The fracture surfaces presented circular crack fronts and the da/dN-DK curves showed a great influence of atmosphere on fatigue crack growth. An average difference of 50% was found between the results in air and vacuum. Therefore, this geometry with internal crack is an interesting alternative to through-thickness geometries.

Development of cryogenic extraction system for δ18O and δ2H measurement of water in soils and plants.

<p>The stable isotope composition of water (δ<sup>18</sup>O and δ<sup>2</sup>H) represents a useful tool to distinguish among different water pools along the soil-plant-atmosphere continuum. Using δ<sup>2</sup>H and δ<sup>18</sup>O as tracers helps gain a better understanding of plant root water uptake and dominant ecohydrological processes. To determine which pools of water are used for plant physiologic functions and returned to the atmosphere by transpiration, a common approach is to analyze the isotopic composition of water in both soil and plant. Cryogenic water extraction (CWE; Orlowski et al., 2016) is the most widely used laboratory-based technique to extract water from soil samples for isotopic analysis. However, recent studies have shown that the extraction conditions (time, temperature, and vacuum) and soil physical and chemical properties may affect the extracted soil-water isotope composition even significantly.</p><p>We have developed an efficient and cost-effective cryogenic vacuum equipment to extract water from soil or vegetation and this presentation aims at discussing some preliminary results. The equipment has been specifically designed to meet the following requirements: i) enable to quantify the accuracy of a CWE continuous flow extraction line, and ii) identify a specific extraction standard protocol for soil and vegetation samples. Two experiments have been carried out to evaluate the isotope fractionation induced by the system and how different operational parameters (i.e. times and temperature of extraction) can affect the results. Firstly, a known water isotopic ratio was processed by the vacuum system to determine the measurement accuracy and reproducibility by comparing pre- and post-processed water isotopic signatures. The likely causes of observed biases induced by sample processing are assessed and a relevant correction procedure is suggested. Subsequently, measurements were carried out on replicated samples taken from two differently-textured soils that, after being dried, were saturated in the laboratory up to different water content values with water of known isotopic composition. Also, plant samples were collected from plants grown in a greenhouse and irrigated with water of known isotopic composition.</p><p>Water from all samples was extracted by our CWE system and then analyzed using an isotope ratio mass spectrometer in Gas Bench mode for analyses and in temperature conversion elemental analysis (TC/EA) mode for. Preliminary results have quantified the isotope fractions on average of -1.6 ‰ for δ<sup>18</sup>O and 14.2 ‰ for δ<sup>2</sup>H. Normalization of stable isotopes from unknown samples according to observed fractionation has enabled the observed bias to become virtually zero, leading to a replicate reproducibility of δ<sup>18</sup>O and δ<sup>2</sup>H for soil water of 0.6 ‰ and 3 ‰, respectively. The analyses carried out up to now did not find statistical evidence that the soil types and soil-water contents may affect the extraction method and the accuracy of our protocol.</p>

Controlling soil disturbance of a lunar regolith simulant bed during depressurization in a vacuum chamber

A dusty thermal vacuum chamber (DTVC) containing a regolith simulant bed is essential for testing equipment and techniques related to lunar surface exploration. Space agencies have been reluctant to operate a DTVC because of the challenge of controlling soil disturbance of the lunar regolith simulant bed during pumping down or depressurization, which may contaminate or even damage the chamber and vacuum equipment. There appears to be no previously available solution to this problem, or how to avoid it. We investigated the mechanism of soil disturbance during depressurization and established a criterion for evaluating its occurrence. The proposed criterion was validated by extensive experiments and numerical modelling to simulate air evacuation from soil voids. There is a critical pressure difference (CPD) between the top and bottom of the lunar regolith simulant bed that causes soil disturbance during depressurization. We found a simple equation estimating the CPD and further provided guideline on the optimum depressurization rate to avoid soil disturbance before the target vacuum level is achieved under varying soil conditions.

NIVELES DE ACCIDENTABILIDAD EN OPERADORES DE VACUUMS Y RIESGOS LABORALES

El presente estudio tuvo por objetivo identificar los niveles de accidentabilidad y riesgos laborales del personal que opera con equipos vacuums, que constituyen camiones de vacío para succión, transporte y evacuación de fluidos, en la empresa de servicios petroleros Conexpet Cía. Ltda. El estudio de caso es descriptivo, con investigación de campo efectuada a 89 operadores, apoyado en revisión bibliográfica-documental, indagando especificar propiedades y características de las personas en su desempeño laboral. La evaluación dio como resultado un déficit en la selección, capacitación y entrenamiento del talento humano, permitiendo luego de la valoración, implementar competencias asociadas a riesgos laborales. Se concluye que existe una relación directa entre el nivel de accidentabilidad y los riesgos laborales, debido a que un 85% de los accidentes laborales presentados en la empresa, son producidos por acciones subestándar. Las estrategias y competencias propuestas pueden replicarse, obteniendo entre otras ventajas: reducción de tiempo perdido, menor costo de mano de obra para reemplazos, baja rotación de personal, mayor productividad y competitividad.Palabras clave: Riesgos laborales, Vacuums, Accidentabilidad, Talento Humano, Competencias Laborales. AbstractThe objective of this study was to identify the levels of accidents and occupational risks of personnel working with vacuum equipment, which constitute vacuum trucks for suction, transport and fluid evacuation, at the oil services company Conexpet Cía. Ltda. The case study is descriptive, with field research carried out on 89 operators, supported by bibliographic-documental review, asking to specify properties and characteristics of people in their work performance. The evaluation resulted in a deficit in the selection, training and training of human talent, allowing after assessment, implement skills associated with occupational risks. It is concluded that there is a direct relationship between the level of accident rate and occupational risks, because 85% of work accidents presented in the company are produced by substandard actions. The proposed strategies and competences can be replicated, obtaining among other advantages: reduction of lost time, lower cost of labor for replacements, low turnover of personnel, greater productivity and competitiveness. Key words: Occupational Risks, Vacuums, Accident, Human Talent, Labor Competencies.

ИННОВАЦИОННОЕ РАЗВИТИЕ РОССИЙСКОГО ЦЕНТРА ВАКУУМНОГО МАШИНОСТРОЕНИЯ

Статья посвящена инновационному этапу развития АО «Вакууммаш», являющегося ведущим предприятием по разработке и выпуску вакуумной техники. Приведены основные направления разработок новой продукции. The article is devoted to the innovative stage of development of “Vacuummash” JSC, which is the leading enterprise for development and production of vacuum equipment. The main directions of development of new products are given.