Biological conversion of hydrogen sulfide to elemental sulfur in a suspended-growth continuous stirred-tank reactor.

A biological process employing green sulfur bacteria was investigated to remove sulfide (S\sp{=}) from industrial wastewaters and convert it to elemental sulfur. This research is unique in that dissolved sulfide was present in the liquid influent fed into a continuous-flow photosynthetic bioreactor. A suspended-growth once-through continuous-flow stirred-tank bioreactor was successfully operated under five different experimental conditions. For the first three experiments, concentrated nutrient solution and sulfide stock solution were pumped separately into a 13.7 L reactor at a hydraulic retention time of 45 hours and S\sp{=} loading rates of 2.1, 4.4, and 5.6 mg/h$\cdot$L. At the lowest loading rate, nearly all influent S\sp{=} was oxidized to sulfate. The middle loading rate resulted in complete conversion of S\sp{=} to S\sp0. Steady state conditions were not achieved at the highest loading rate, resulting in the accumulation of S\sp{=} in the bioreactor. In two more experiments, nutrient medium and S\sp{=} stock solution were separately fed into a 12.0 L bioreactor at S\sp{=} loading rates of 3.2 and 2.7 mg/h$\cdot$L, and hydraulic retention times of 173 and 99 hours respectively. In these trials, the loading rates were adjusted to maintain a residual of S\sp{=} in the bioreactor, and consequently, there was nearly complete conversion of the consumed S\sp{=} to S\sp0. A parameter was developed to relate the experiments of this dissertation with those reported in the literature, where smaller reactors and higher bacterial concentrations were used in batch reactors fed with \rm H\sb2S\sb{(g)}. This parameter described the capacity of the bioreactor to consume S\sp{=}, and was calculated as the product of the radiant flux per unit reactor volume and the bacteriochlorophyll concentration. Three predictive models were developed for the bioreactor. In the yield-based model, a yield coefficient was used to link the increase in bacteriochlorophyll with the consumption of S\sp{=}. Poor correlations between the rates of reaction and the concentrations of the reactant sulfur species led to the conclusion that a reaction pathway-based model was not appropriate for this system. An empirical model was proposed to relate the reactor volume, S\sp{=} loading rate, reactor irradiation and bacteriochlorophyll concentration.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .H465. Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4554. Adviser: J. K. Bewtra. Thesis (Ph.D.)--University of Windsor (Canada), 1996

Engineering standards for trauma and orthopaedic implants worldwide : a systematic review protocol

Introduction Despite multiple scandals in the medical implant sector, premarket testing has been the attention of little published research. Complications related to new devices, such as the DePuy Articular Surface Replacement (ASR, DePuy Synthes, USA), have raised the issue of how designs are tested and whether engineering standards remain up to date with our understanding of implant biomechanics. Despite much work setting up national joint registries to improve implant monitoring, there have been few academic studies examining the premarket engineering standards new implants must meet. Emerging global economies mean that the markets have changed, and it is unknown to what degree engineering standards vary around the world. Governments, industry and independent regulatory bodies all produce engineering standards; therefore, the comparison of surgical implants across different manufacturers and jurisdictions is difficult. In this review, we will systematically collate and compare engineering standards for trauma and orthopaedic implants around the world. This will help inform patient, hospital and surgeon choice and provide an evidence base for future research in this area. Methods and analysis This protocol is based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) guidelines. We will conduct a systematic review of trauma and orthopaedic engineering standards from four main sources of information as identified in our preliminary scoping searches: governments, industry, independent regulatory bodies and engineering and medical publications. Any current standard relevant to trauma and orthopaedic implants will be included. We will use a predefined search strategy and follow the recommendations of the Cochrane handbook where applicable. We will undertake a narrative synthesis with qualitative evaluation of homogeneity between engineering standards. Ethics and dissemination No ethics approval is required as no primary data are being collected. The results will be made available by peer-reviewed publication and reported according to PRISMA-P guidelines

Quantum Electronics

Contains research objectives and summary of research on eight projects in three sections and reports on two research projects.U. S. Air Force - Office of Scientific Research (Contract F44620-71-C-0051)Joint Services Electronics Program (Contract DAAB07-74-C-0630)University of California, Livermore (Subcontract No. 7877409)U. S. Army Research Office - Durham (Contract DAHC04-72-C-0044

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The cause and meaning of this war /

No. 4 in vol. lettered: World War, 1914-1918. Pamphlets, 14.Cover title.Mode of access: Internet

Report upon natural history collections made in Alaska between the years 1877 and 1881

Issued also in the Congressional series of U.S. public documents (no. 2349) as Senate misc. doc. no. 156, 49th Cong., 1st sess."Partial bibliography of Alaskan ornithology": p. 223-226.Letter of transmittal, by H. W. Henshaw.--Narrative, by E. W. Nelson.--pt. I. Birds of Alaska, with partial bibliography of Alaskan ornithology, by E. W. Nelson.--pt. II. Mammals of northern Alaska, by E. W. Nelson and F. W. True.--pt. III. Field notes on Alaskan fishes, by E. W. Nelson, with additional notes by Tarleton H. Bean.--pt. IV. Insects. Report upon the diurnal Lepidoptera collected in Alaska by E. W. Nelson, by W. H. Edwards.Mode of access: Internet