Laser pulse annealing of ion-implanted GaAs

GaAs single-crystals wafers are implanted at room temperature with 400-keV Te + ions to a dose of 1×10^15 cm^–2 to form an amorphous surface layer. The recrystallization of this layer is investigated by backscattering spectrometry and transmission electron microscopy after transient annealing by Q-switched ruby laser irradiation. An energy density threshold of about 1.0 J/cm^2 exists above which the layer regrows epitaxially. Below the threshold the layer is polycrystalline; the grain size increases as the energy density approaches threshold. The results are analogous to those reported for the elemental semiconductors, Si and Ge. The threshold value observed is in good agreement with that predicted by the simple model successfully applied previously to Si and Ge

Benefits and medium-term outcome of the Sorin Pericarbon Freedom stentless aortic prosthesis in cases of acute bacterial endocarditis

OBJECTIVES The aim of this study is to evaluate the ease of use and the advantages of Sorin Pericarbon Freedom (SPF) stentless valve in cases of acute bacterial endocarditis and to check the intermediate-term results after the implant of SPF with respect to resistance to infection, valve deterioration and durability. METHODS Between June 2003 and February 2015, 26 patients with active aortic valve bacterial endocarditis underwent aortic valve replacement with SPF pericardial stentless aortic prosthesis. The mean age was 57 \ub1 18 years; 73% of the patients were in preoperative NYHA class III and VI. Mean Logistic EuroSCORE was 14.2 \ub1 12.7. Endocarditis occurred in 18 patients with native valves, and in 9 patients with prosthetic valves (4 mechanical aortic valve prostheses; 5 aortic bioprostheses). Aortic root abscesses were observed in 16 cases (61.5%). Surgery was emergent in 3 cases (11.5%). Redo surgery was performed in 9 cases (35%). Cumulative follow-up was 126.8 patient-years (mean 4.9 \ub1 3.3 years). RESULTS Operative hospital mortality was 0% for all patients. Residual mean prosthetic gradient at discharge was 9.4 \ub1 3.6 mmHg. Neither residual aortic incompetence nor residual abscess cavity was observed at discharge. Mean ejection fraction at discharge was 54 \ub1 8% (Min; Max: 35%; 65%). A total of 4 patients died at follow-up, all for non-cardiac causes. One patient was lost to follow-up. Two patients (8%) underwent non-valve-related reoperation with 0% mortality. Residual mean gradient at follow-up was 7.2 \ub1 2.1 mmHg. Three patients (17%) presented with mild/moderate aortic incompetence and 89% of patients were in NYHA Class I-II at follow-up. At 9 years, actuarial freedom from valve-related reoperation and from structural valve deterioration was 100%. CONCLUSIONS The SPF aortic prosthesis is a true pericardial stentless prosthesis suitable for the treatment of acute bacterial endocarditis. Intermediate-time results in terms of freedom from reoperation, structural valve deterioration and resistance to infections are satisfactory. Haemodynamic performances are excellent since a complete exclusion of aortic root abscesses is achieved without any reduction of the aortic annular diameter, usually due to marsupialization or patch closure of the infected cavities

Urban rainwater harvesting systems: Research, implementation and future perspectives.

Published onlineJournal ArticleReviewThis is the author accepted manuscript. The final version is available from IWA Publishing via the DOI in this record.While the practice of rainwater harvesting (RWH) can be traced back millennia, the degree of its modern implementation varies greatly across the world, often with systems that do not maximize potential benefits. With a global focus, the pertinent practical, theoretical and social aspects of RWH are reviewed in order to ascertain the state of the art. Avenues for future research are also identified. A major finding is that the degree of RWH systems implementation and the technology selection are strongly influenced by economic constraints and local regulations. Moreover, despite design protocols having been set up in many countries, recommendations are still often organized only with the objective of conserving water without considering other potential benefits associated with the multiple-purpose nature of RWH. It is suggested that future work on RWH addresses three priority challenges. Firstly, more empirical data on system operation is needed to allow improved modelling by taking into account multiple objectives of RWH systems. Secondly, maintenance aspects and how they may impact the quality of collected rainwater should be explored in the future as a way to increase confidence on rainwater use. Finally, research should be devoted to the understanding of how institutional and socio-political support can be best targeted to improve system efficacy and community acceptance

Studies on the Al2O3–Ti–Mo–Au metallization system

The behavior of Ti–Mo–Au metallization on Al2O3 and C has been investigated by backscattering spectrometry. Results show that Mo–Au bimetal films typically mix during deposition. Diffusion of Ti in Mo film occurs at 600°C, but is inhibited by the presence of oxygen in the Ti film. Even 1000 Å of Mo is not a barrier against interdiffusion of Ti and Au during 20–min anneals at 600°C. The amount of mixing observed also depends on the nature of the substrate which supports the Ti–Mo–Au metallization

Rainwater harvesting systems reduce detergent use

Unidad de excelencia María de Maeztu MdM-2015-0552Purpose: Due to population growth, urban water demand is expected to increase significantly, as well as the environmental and economic costs required to supply it. Rainwater harvesting (RWH) systems can play a key role in helping cities meet part of their water demand as an alternative to conventional water abstraction and treatment. This paper presents an environmental and economic analysis of RWH systems providing households with water for laundry purposes in a life cycle thinking perspective. Conclusions: LCA and LCC present better results for high-density scenarios. Overall, avoided environmental and economic impacts from detergent reduction clearly surpass environmental impacts (in all categories except terrestrial acidification) and economic cost of the RWHsystem in most cases (except two scenarios). Another important finding is that 80%of the savings are achieved by minimizing detergent and fabric softener by using soft rainwater; and the remaining 20% comes from replacing the use of tap water