Cleanliness Control Before Bonding and Welding

As the key part for energy amplification of high-power laser systems, disk amplifiers must work in an extremely clean environment. Different from the traditional cleanliness control scheme of active intake and passive exhaust (AIPE), a new method of active exhaust and passive intake (AEPI) is proposed in this paper. Combined with computational fluid dynamics (CFD) technology, through the optimization design of the sizes, shapes, and locations of different outlets and inlets, the turbulence that is unfavorable to cleanliness control is effectively avoided in the disk amplifier cavity during the process of AEPI. Finally, the cleanliness control of the cavity of the disk amplifier can be realized just by once exhaust. Meanwhile, the micro negative pressure environment in the amplifier cavity produced during the exhaust process reduces the requirement for sealing. This method is simple, time saving, gas saving, efficient, and safe. It is also suitable for the cleanliness control of similar amplifiers.

ABSTRACTIntroduction:To complement the Swachhata Abhiyaan effort, the Ministry of Health and Family Welfare, initiated “KAYAKALP.” Kayakalp is an initiative to improve the cleanliness, hygiene, and sanitation of public health facilities by recognizing and giving awards to those who exhibit a high level of cleanliness, hygiene, and infection control. Our study aimed to assess the level of cleanliness, hygiene, and infection control practices in the health care facility after undertaking by the department of Community Medicine of a medical college.Methodology:A retrospective comparative observational study was conducted at RHTC in the Kathua district of UT J and K. We compare the level of cleanliness, hygiene, and infection control practices using the Kayakalp scoring tool before and after taking over by the department of Community Medicine of a medical college. The scoring for various areas of concern is based on a checklist for quality assessment which includes facility upkeep, sanitation and hygiene, waste management, and infection control.Results:The total scores vary before and after undertaking of a Primary Health Center (PHC) by the Community Medicine Department of new medical college of J and K. Overall scores vary from the baseline score of 56% before to 84% now after 2 years of the undertaking.Conclusion:Resource management and capacity building under the guidance of public health professionals can result in a significant increase in hygiene, cleanliness, and infection control. So integrated approach involves public health specialists and other medical professionals like medical officers, field workers, sanitary inspectors. etc., can be helpful in recognizing the challenges and barriers.

Abdominal wall reconstruction in patients presenting with enteric fistulas and mesh infection is challenging. There is a consensus that synthetic mesh must be avoided in infected operations, and the alternatives to using synthetic mesh, such as component separation techniques and biologic mesh, present disappointing results with expressive wound infection and hernia recurrence rates. A prospective clinical trial designed to evaluate the short- and long-term outcomes of 40 patients submitted to elective abdominal wall repair with synthetic mesh in the dirty-infected setting, and compared to a cohort of 40 patients submitted to clean ventral hernia repairs. Patients in both groups were submitted to a single-staged repair using onlay polypropylene mesh reinforcement. Groups' characteristics were similar. There were 13 (32.5%) surgical site occurrences in the infected mesh (IM) group, compared to 11 (27.5%) in the clean-control (CC) group, p = 0.626. The 30-day surgical site infection rate was 15% for the IM group vs. 10% for the CC cases, p = 0.499. One patient required a complete mesh removal in each group. The mean overall follow-up was 50.2 ± 14.8months, with 36 patients in the IM group and 38 clean-controls completing a follow-up of 36months. There was one hernia recurrence (4.2%) in the IM group and no recurrences in the CC group. We demonstrated that using polypropylene mesh in the infected setting presented similar outcomes to clean repairs. The use of synthetic mesh in the onlay position resulted in a safe and durable abdominal wall reconstruction. Study registered at Plataforma Brasil (plataformabrasil.saude.gov.br), CAAE 30836614.7.0000.0068. Study registered at Clinical Trials (clinicaltrials.gov), Identifier NCT03702153.

The aim of this study was to evaluate the amount of dust in supply air ducts in recently installed ventilation systems. The samples for the determination of dust accumulation were collected from supply air ducts in 18 new buildings that have been constructed according to two different cleanliness control levels classified as category P1 (low oil residues and protected against contaminations) and category P2, as defined in the Classification of Indoor Climate, Construction and Building Materials. In the ducts installed according to the requirements of cleanliness category P1 the mean amount of accumulated dust was 0.9 g/m2 (0.4-2.9 g/m2), and in the ducts installed according to the cleanliness category P2 it was 2.3 g/m2 (1.2-4.9 g/m2). A significant difference was found in the mean amounts of dust between ducts of categories P1 and P2 (P < 0.008). The cleanliness control procedure in category P1 proved to be a useful and effective tool for preventing dust accumulation in new air ducts during the construction process. Additionally, the ducts without residual oil had lower amounts of accumulated dust indicating that the demand for oil free components in the cleanliness classification is reasonable.

Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and the formation of structures over cosmological timescales. It will operate at L2 and it will survey about 36% of the sky on a 6 year mission, all with high image quality and stability. To allow such scientific achievements, an integrated cleanliness and contamination control (CCC) have been put in place covering all phases of Euclid development until end of operations. This document describes the design challenges, the engineering and AIT solutions used to control and to monitor the entire mission life time contamination from organic and particulate sources as well as the in-orbit water ice contamination.

As an important export, cleanliness control on edible bird’s nest (EBN) is paramount. Automatic impurities detection is in urgent need to replace manual practices. However, effective impurities detection algorithm is yet to be developed due to the unresolved inhomogeneous optical properties of EBN. The objective of this work is to develop a novel U-net based algorithm for accurate impurities detection. The algorithm leveraged the convolution mechanisms of U-net for precise and localized features extraction. Output probability tensors were then generated from the deconvolution layers for impurities detection and positioning. The U-net based algorithm outperformed previous image processing-based methods with a higher impurities detection rate of 96.69% and a lower misclassification rate of 10.08%. The applicability of the algorithm was further confirmed with a reasonably high dice coefficient of more than 0.8. In conclusion, the developed U-net based algorithm successfully mitigated intensity inhomogeneity in EBN and improved the impurities detection rate.

Cleanliness control is one of the most important processes for final optics assembly (FOA) in high-power laser systems. In this paper, an “Ultra Clean Manufacturing (UCM)” concept is put forward for the first time to satisfy the cleanliness requirements for FOA. First, the challenges and requirements for cleanliness in FOA are introduced and the concept of UCM is proposed. Significant surface cleaning technologies for mechanical parts and optics are then expounded. Finally, surface cleanliness control techniques, such as “gas knife” and “laser cleaning”, are developed as online cleaning methods for the surface cleanliness in FOA.

Laser damage studies were recently introduced at LOSCM. We first describe our experimental set-up and its performances. The device is equipped with a 7 ns Nd : Y AG pulsed laser. Surface modifications due to laser irradiation are observed in real time through a Nomarski microscope placed behind the sample along the optical axis. The beam is aligned with a He-Ne laser and focused in a spot of 25 μmin diameter, which permits a localized study and the determination of intrinsic and extrinsic damage thresholds. The LIDT is determined by the real time Nomarski observation. To go further into the analysis of laser impact we use an Atomic Force Microscope with a micrometric repositioning system that permits a quantitative study. We detail the first results concerning LIDT and morphology of several materials produced by electron beam deposition at LOSCM (Zns, Na~IF6, Si02, Ta20 5, Hf02 and multidielectric mirrors). The whole characterization is performed in strong correlation with deposition parameters and cleanliness control, which allow us to draw a set of preliminary conclusions.

Optical microscopy, total oxygen measurements and slime tests have been conducted to quantify the size distribution and amount of inclusions at various processing steps during basic oxygen furnace (BOF) based steel production at Baosteel. The effects on steel cleanliness of specific operational improvements during steel refining and continuous casting have been investigated. Such improvements to these processes and the resulting level of steel cleanliness at Baosteel are summarised in the present paper. Ladle slag reduction lowers FeO+MnO in the slag to below 5%, decreasing steel reoxidation by the slag. Calcium treatment by CaSi wire injection during ladle furnace (LF) refining is used to modify inclusions and improve submerged entry nozzle (SEN) clogging. Slag detection is employed at the ladle bottom during continuous casting. Flow control devices, CaO containing filters and high CaO based basic powder with CaO/SiO2>4 are used in the tundish to remove more inclusions. Several improvements to the castability and in the attainment of clean steel at mould operations have also been made. With this BOF based steelmaking process, impurity levels can be controlled to achieve total oxygen (TO)<16 ppm, [S]<5 ppm, [P]<35 ppm, [N]<29 ppm, [H]<1 ppm in line pipe steels, and [C]<16 ppm, TO<19 ppm, [N]<15 ppm in interstitial free (IF) steels.

The Jiangmen Underground Neutrino Observatory (JUNO) is building a 20-kt liquid scintillator detector in a laboratory 700 m underground to address many important topics in neutrino and astro-particle physics. A clean and low radon environment is quite important to build an ultra-pure detector with the lowest radioactive background. In this work, we present the main strategies of radon and cleanliness control at JUNO. The total volume of the experimental hall is about 120,000 m 3 . We have implemented clean room management in the laboratory, and the final cleanliness can be equivalent to class 10,000-100,000 level. There is a large amount of underground water at the JUNO site, and the flow rate can reach 450 m 3 /h with 120,000 Bq/m 3 radon concentration in the water. We have validated that the underground water is a big radon source for radon in underground air. The nominal radon concentration in the main hall is required to be below 200 Bq/m 3 for human beings' health and neutrino physics, and the maximum value should be below 400 Bq/m 3 . With great efforts on optimization of the ventilation underground and well isolation of the experimental hall, the final radon concentration in the main hall has reached 100-200 Bq/m 3 .

Planetary protection: Elements for cost minimization

Cleanliness of Alloying Structural Steel

Space systems. Contamination and cleanliness control

Wind turbine gearbox is one of the most expensive and critical components of the wind turbine generator system. Due to the extreme operating conditions encountered in the gearbox, there is little room for compromises, especially with the performance of the lubrication system. Gearbox lubricating fluid is one of the most important elements of the system—it is analogous to the blood in human body, performing key functions, which in the case of gearbox are maintaining proper lubricity and film thickness between the moving surfaces, heat absorption and its dissipation, suspension and transportation of the particulate debris, prevention of abrasion and corrosion, etc., in the lubrication system. Therefore, the optimum cleanliness level and health of the lubricating fluid is essential for satisfactory performance and service life of the wind turbine gearbox. The paper discusses the cleanliness control and management of the gearbox lubrication system. Examples of filtration related issues experienced in the field are also discussed.

The evolution of oxide inclusions and cleanliness control in Al-killed GCr15SiMn bearing steel was investigated using a combination of industrial tests and thermodynamic calculations during the secondary refining process. Three different refining conditions were employed in the LF process. With varying ranges of slag basicity (about 5.6–5.7, 4.8–4.9 and 3.9–4.3) and Al content (0.028–0.035 mass%, 0.023–0.025 mass% and 0.014–0.02 mass%), the total oxygen content in the steel after VD refining was measured as 0.0019 mass%, 0.0017 mass% and 0.0008 mass%, respectively. Throughout the refining process, the inclusions underwent a transformation from MgO-Al2O3 (or Al2O3) into CaO-Al2O3(-MgO), and eventually to CaO-Al2O3-SiO2 inclusions. Furthermore, it was observed that under high Al content and slag basicity refining conditions, a significant number of inclusions in VD treatment were formed and transformed into CaO·Al2O3·SiO2 inclusions enriched with 60 mass% CaO. This indicated that when the proportion of CaO in calcium aluminates exceeded 45 mass%, there was an increased risk of larger-sized inclusions. Conversely, refining conditions with a slag basicity of 3.9–4.3 and an Al content of 0.014–0.02 mass% demonstrated effective inclusion control, resulting in lower number density, smaller sizes within 10 μm and an average composition located in the liquid region. This study carries important practical significance for the smelting of high cleanliness GCr15SiMn bearing steel.