Lubricant self-replenishing slippery surface with prolonged service life for fog harvesting

Slippery lubricant-infused surfaces exhibit excellent fog-harvesting capacities compared with superhydrophobic and superhydrophilic surfaces. However, lubricant depletion is typically unavoidable under dynamic conditions, and reinfused oil is generally needed to recover the fog-harvesting capacity. Herein, an effective strategy for delaying the depletion of lubricant to prolong the service life of fog harvesting is proposed. An ultrathin transparent lubricant self-replenishing slippery surface was fabricated via facile one-step solvent evaporation polymerization. The gel film of the lubricant self-replenishing slippery surface, which was embedded with oil microdroplets, was attached to glass slides via the phase separation and evaporation of tetrahydrofuran. The gel film GFs-150 (with oil content 150 wt% of aminopropyl-terminated polydimethyl siloxane (PDMS-NH2)) exhibited superior slippery and fog-harvesting performance to other gel films. Furthermore, the slippery surfaces with the trait of oil secretion triggered by mechanical stress exhibited better fog-harvesting capabilities and longer service life than surfaces without the function of lubricant self-replenishment. The lubricant self-replenishing, ultrathin, and transparent slippery surfaces reported herein have considerable potential for applications involving narrow spaces, visualization, long service life, etc.

Failure Analysis of Stainless Steel Sheets of Heat Shield Assembly of a Vacuum Degassing Furnace

A twenty-five-year-old vacuum furnace is being used for degassing of ultra-high vacuum components. The heat shield assembly of the furnace comprised of one molybdenum (Mo) front sheet, followed by four 304 stainless steel (SS) sheets. During prolonged service of the furnace, SS sheets developed thick black oxide scale. As a part of refurbishment drive, the SS sheets were subjected to chemical cleaning in 20 % HNO3 + 1.5 % HF, which caused severe thinning along the edges of some sheets. Detailed analysis of a damaged SS sheet showed that the damage was caused by severe sensitization of edge region which underwent extensive intergranular corrosion during chemical cleaning. Important remedial measures suggested to avoid similar failures included: (i) use of type 316L or stabilized grades of austenitic SS sheets, (ii) use of two Mo front sheets in place of one and (iii) use of mechanical cleaning in place of chemical cleaning.

Serving as a Temporary Pathology Chair: “Boon” or “Boondoggle”?

The 2019 Association of Pathology Chairs Annual Meeting included a discussion group sponsored by the Senior Fellows Group (former chairs of academic departments of pathology who have remained active in Association of Pathology Chairs) that was focused on serving as temporary pathology chair. Such positions include “acting chair” (service while the permanent chair is on leave or temporarily indisposed), “interim chair” (service after departure of the prior chair and before a new chair is appointed), “term-limited chair” (usually one nonrenewable term of less than 5 years), and “terminal chair” (permanent chair being asked to stay until a successor is appointed). Discussion group panelists represented each of these positions and included the perspective of 3 former deans about the rationale for making such appointments. The potential benefits and risks of serving in these roles were discussed. Issues addressed included acting as “caretaker manager” or “change-agent leader”; whether such service and experience would enhance or harm one’s chances to become a permanent chair of that or another department; the effect of such service on academic productivity; the influence of department and institutional factors on the position; the range of authority provided, particularly in addressing significant problems affecting the department’s future; and the impact of time served in these various positions. The “lame-duck” effect of prolonged service as “terminal chair” was also discussed. The observations and advice provided by the panelists and audience discussion are reported and may be useful for those considering service as temporary chair in pathology as well as other academic leadership positions.

Adolescent psychosis risk symptoms predicting persistent psychiatric service use: A 7-year follow-up study

Background:We investigated whether psychosis risk symptoms predicted psychiatric service use using seven-year register follow-up data.Methods:Our sample included 715 adolescents aged 15–18, referred to psychiatric care for the first time. Psychosis risk symptoms were assessed with the Prodromal Questionnaire (PQ) at the beginning of the treatment. We assessed the power of the overall PQ as well as its positive, negative, general, and disorganized psychosis risk symptom factors in predicting prolonged service use. Baseline psychiatric diagnoses (grouped into 7 categories) were controlled for. Based on both inpatient and outpatient psychiatric treatment after baseline, adolescents were divided into three groups of brief, intermittent, and persistent service use.Results:Stronger symptoms on any PQ factor as well as the presence of a mood disorder predicted prolonged service use. All of the PQ factors remained significant predictors when adjusted for baseline mood disorder and multimorbidity.Conclusions:In a prospective follow-up of a large sample using comprehensive mental health records, our findings indicate that assessing psychosis risk symptoms in clinical adolescent settings at the beginning of treatment could predict long-term need for care beyond diagnostic information. Our findings replicate the previous findings that positive psychosis risk symptoms are unspecific markers of severity of psychopathology. Also psychosis risk symptoms of the negative, disorganization, and general clusters are approximately as strongly associated with prolonged psychiatric service use in the upcoming years.

Study of Prolonged Service Degradation of Superheater Tubes and its Effects on Remaining Life Predictions

This study investigates the degradation of superheater tubes that has been in service for very long time. It also discusses the degradation effects on tube remaining life predictions. The tubes, utilized in this study, belong to an industrial boiler that has been in service for 232 000 h in a petrochemical plant and generate steam at 47 barg and 410 °C. Outcomes of this study will contribute to better understanding and development of scientific procedures to make reasonable estimate of tube remaining life considering the tubes aging while in service. This is beneficial in preventing failures and forced plant shutdown when life is consumed. It also helps industry to avoid capital expenditures on premature replacements of boiler tubes that can still serve longer time. In this study, comparison is made between short-term life predictions and actual properties found after about 26.5 years of service. The tubes condition is assessed by metallographic, mechanical and stress rupture testing. According to the results, it is found that prolonged service degradation has strong effects on remaining life predictions. Both effects that would lead to overestimating or underestimating tube remaining life were found if existing procedures are used without consideration for material degradation during service.

Investigations on corrosion of aircrafts in the aspect of prolonged service life and operation driven by their technical condition

Research studies that are conducted by both the Air Force Institute of Technology (AFIT) and other domestic and foreign organizations indicate that investigations of corrosion phenomena present a very important factor with respect to prolongation of technical resources and operation of aircraft driven by their actual technical condition. The investigation of the corrosion degree and deterioration of protective coatings must be carried out in a systemic manner with thorough analysis of information that bring together the aircraft operation and the processes of corrosion and deterioration of protective coatings. The investigation must comprise measurements of the atmospheric corrosion in order to determine corrosive aggressiveness of the atmosphere and establish frequency and scope of corrosion inspection. Only the analysis of gathered information with its characteristics may guarantee safe operation of structural components of aircrafts according to their actual technical condition. This paper outlines the approach to corrosion investigation that is in place in AFIT.