Li-S System Research Articles

Cathode Composites for Li–S Batteries via the Use of Oxygenated Porous Architectures

Li-S rechargeable batteries are attractive for electric transportation because of their low cost, environmentally friendliness, and superior energy density. However, the Li-S system has yet to conquer the marketplace, owing to its drawbacks, namely, soluble polysulfide formation. To tackle this issue, we present here a strategy based on the use of a mesoporous chromium trimesate metal-organic framework (MOF) named MIL-100(Cr) as host material for sulfur impregnation. Electrodes containing sulfur impregnated within the pores of the MOF were found to show a marked increase in the capacity retention of Li-S cathodes. Complementary transmission electron microscopy and X-ray photoelectron spectroscopy measurements demonstrated the reversible capture and release of the polysulfides by the pores of MOF during cycling and evidenced a weak binding between the polysulphides and the oxygenated framework. Such an approach was generalized to other mesoporous oxide structures, such as mesoporous silica, for instance SBA-15, having the same positive effect as the MOF on the capacity retention of Li-S cells. Besides pore sizes, the surface activity of the mesoporous additives, as observed for the MOF, appears to also have a pronounced effect on enhancing the cycle performance. Increased knowledge about the interface between polysulfide species and oxide surfaces could lead to novel approaches in the design and fabrication of long cycle life S electrodes.

ISO 15189 Accreditation: Requirements for quality and competence of medical laboratories, experience of a laboratory I

Aim Medical laboratories are the key partners in patient safety. Laboratory results influence 70% of medical diagnoses. Quality of laboratory service is the major factor which directly affects the quality of health care. The clinical laboratory as a whole has to provide the best patient care promoting excellence. Methods International Standard ISO 15189, based upon ISO 17025 and ISO 9001 standards, provides requirements for competence and quality of medical laboratories. Accredited medical laboratories enhance credibility and competency of their testing services. Our group of laboratories, one of the leading institutions in the area, had previous experience with ISO 9001 and ISO 17025 Accreditation at non-medical sections. We started to prepared for ISO 15189 Accreditation at the beginning of 2006 and were certified in March, 2007. We spent more than a year to prepare for accreditation. Results Accreditation scopes of our laboratory were as follows: clinical chemistry, hematology, immunology, allergology, microbiology, parasitology, molecular biology of infection serology and transfusion medicine. The total number of accredited tests is 531. We participate in five different PT programs. Inter Laboratory Comparison (ILC) protocols are performed with reputable laboratories. 82 different PT Program modules, 277 cycles per year for 451 tests and 72 ILC program organizations for remaining tests have been performed. Our laboratory also organizes a PT program for flow cytometry. 22 laboratories participate in this program, 2 cycles per year. Our laboratory has had its own custom made WEB based LIS system since 2001. We serve more than 500 customers on a real time basis. Our quality management system is also documented and processed electronically, Document Management System (DMS), via our intranet. Conclusion Preparatory phase for accreditation, data management, external quality control programs, personnel related issues before, during and after accreditation process are presented. Every laboratory has to concentrate on patient safety issues related to laboratory testing and should perform quality improvement projects.

Conjunctive water management options: examples from economic assessment of system‐level water saving through Liuyuankou Irrigation System, China

AbstractThe paper provides results of a study aimed at saving a substantial amount of water by maintaining deeper groundwater levels to prevent fallow evaporation and by reducing the cost of groundwater abstraction for lowland farmers. An integrated LIS economic appraisal model was developed that linked simulated response of hydrological modelling of different conjunctive management options with economic analysis.The simulation results of the LIS system dynamic model show that a combination of canal lining and pumping groundwater is the most cost‐effective way to reduce non‐beneficial evapotranspiration and increase water availability by saving up to 68 MCM of water. The simulation results of economic parameters indicated that canal lining and pumping also offer highest net economic benefits (¥21.98 million). Among other options, canal lining also indicates reasonably high net economic benefits (¥9.02 million). The model indicates a small increase in marginal value of water with canal lining (¥1.53 m−3) and pumping and canal lining (¥1.62 m−3). Among other options, the marginal capital cost of water saving for pumping and canal lining together was the lowest (¥0.096 m−3). However, the marginal capital cost of water saving for pumping and shifting canal water downstream was the most expensive (¥1.046 m−3). Copyright © 2007 John Wiley & Sons, Ltd.

Entwicklung und aktueller Stand winkelstabiler Plattensysteme

Fixed-angle systems for use in internal fixatiion have been widely familiar since the advent of the fiixateur externe. In recent years use of the fixed-angle principle has quickly become widespread, especially in the case of plating systems. The development of the angled plate is described and illustrated with reference to the cervical spinal plate, the PC-Fix with limited contact and the LIS system, and the development of fixation with fixed-angle plates is explained. With these plates the classic principle of stability attained through friction has been abaandoned, and they can more accurately be described as fixateurs internes, since contact with the bone is no longer necessary with plates of the newest generation. The fixed-angle plates have biomechanical advantages, which have already proved their worth in practical use. Scientific studies on the various clinical applications are ongoing in many clinics. Whether these systems, which involve distinctly higher costs, become accepted for general use, will depend not least on the results of these studies.

INFLUENCE OF ANAEROBIC DIGESTION ON DAIRY MANURE PHOSPHORUS EXTRACTABILITY

On-farm anaerobic treatment is used for solids, odor and pathogen removal, and energy recovery. Not much information is available on the effect of this treatment method on phosphorus (P) dynamics. The objective of this study was to investigate the effect of different inoculum-to-substrate ratios (ISR) on P extractability from anaerobically digested dairy manure. Dairy manure (substrate) and anaerobically digested dairy manure (inoculum) were collected from a full-scale on-farm anaerobic digester. High ISR (HIS, with ISR = 2.0) and low ISR (LIS, with ISR = 0.3) samples were prepared on a volatile solids (VS) basis. These samples were subjected to mesophilic (35°C) anaerobic digestion in batch reactors without mixing for 120 d. Specific methane yield, TS, and VS removal were higher in the LIS system compared to the HIS system. Serial and repeated extraction methods were used to characterize P extractability. De-ionized (DI) water and MgCl2 were used as extractants in the serial extraction method with extractant-to-manure ratios (EMR) ranging from 3 to 127. For repeated extraction, manure was extracted six times with DI water (EMR = 3). While anaerobic treatment decreased water-extractable P (WEP) in LIS extracts at EMR values of 3 and 7 by 28% and 24%, respectively, a significant increase (40%) in WEP occurred at an EMR of 3 at HIS. Water-extractable P in all other serial extracts of treated manure was higher than that in extracts of untreated manure regardless of ISR and EMR. Extractability of P increased sharply up to the third extraction step, after which it leveled off. The effectiveness of anaerobic digestion at LIS to reduce P extractability was also observed up to the second extraction step. In contrast, the digested manure always produced higher WEP levels for the HIS system. Our results indicate that, depending on the ISR used, anaerobic digestion of dairy manure can increase or decrease manure P extractability and, hence, its availability in runoff. However, it appears that this impact could be more pronounced under conditions where low runoff volumes are generated and for the first few precipitation events after land application of manure.

The two-level approach to data definition and space management in the LIS system implementation language

It has often been remarked that surprisingly few parts of the algorithms which define an operating system require the use of unsafe, low-level language features {1}. Nevertheless, the lack of safety inherent in these parts will propagate to the whole system if an appropriate methodology is not used. It seems desirable to structure programs in such a way that parts with different safety levels are clearly separated and identifiable. The LIS solution to this problem involves the use of two language levels which are used in separate contexts. The general language is a Pascal-like language with the safety that this implies {2, 3}. On the other hand, the use of unsafe features is restricted to so-called implementation parts associated with each declaration level of the program. Several authors {4, 5, 6} have pointed out the advantages of having a two-step data definition, namely, a first step concerned with the semantic properties and a second dealing with the effective realization. In what follows we present the LIS approach to this question and show that the safety levels inherent to these two steps are different. The second step requires implementation specifications which appear in implementation parts.