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Modified Design (modified + design)
Selected AbstractsExperimental study on sulfur trioxide decomposition in a volumetric solar receiver,reactorINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2009Adam Noglik Abstract Process conditions for the direct solar decomposition of sulfur trioxide have been investigated and optimized by using a receiver,reactor in a solar furnace. This decomposition reaction is a key step to couple concentrated solar radiation or solar high-temperature heat into promising sulfur-based thermochemical cycles for solar production of hydrogen from water. After proof-of-principle a modified design of the reactor was applied. A separated chamber for the evaporation of the sulfuric acid, which is the precursor of sulfur trioxide in the mentioned thermochemical cycles, a higher mass flow of reactants, an independent control and optimization of the decomposition reactor were possible. Higher mass flows of the reactants improve the reactor efficiency because energy losses are almost independent of the mass flow due to the predominant contribution of re-radiation losses. The influence of absorber temperature, mass flow, reactant initial concentration, acid concentration, and residence time on sulfur trioxide conversion and reactor efficiency has been investigated systematically. The experimental investigation was accompanied by energy balancing of the reactor for typical operational points. The absorber temperature turned out to be the most important parameter with respect to both conversion and efficiency. When the reactor was applied for solar sulfur trioxide decomposition only, reactor efficiencies of up to 40% were achieved at average absorber temperature well below 1000°C. High conversions almost up to the maximum achievable conversion determined by thermodynamic equilibrium were achieved. As the re-radiation of the absorber is the main contribution to energy losses of the reactor, a cavity design is predicted to be the preferable way to further raise the efficiency. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modified stack inverted-F antenna with corner-truncated techniques for WLAN 2.4/5 GHz band applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2006Chung Ping Liu Abstract A modified design of stack inverted-F antenna with corner truncated technique for 2.4/5.0 GHz dual-band applications is presented in this paper. The new stack inverted-F antenna consists of two parts, one is M-shaped and the other is F-shaped. For current distributions, proposed F-shaped configuration determines the certain resonated frequencies of desired bands (4.98,5.25 GHz) and the M-shaped configuration depicts the range of 2.40,2.75 GHz. It is a compact and available microstrip antenna for IEEE 802.11a/b WLAN,s applications. Simulation and experimental results with frequency responses, radiation patterns, and current distributions are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2378,2381, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21960 [source] The influence of an internal electric field upon protein crystallization using the gel-acupuncture methodACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2003N. Mirkin In this work, the influence of an internal electric field upon the crystallization of lysozyme and thaumatin is explored using a modified design of the gel-acupuncture setup. From a crystallographic point of view, the orientation of crystals that grow preferentially over different types of electrodes inside capillary tubes is also evaluated. Finally, the crystal quality and the three-dimensional structure of these proteins grown with and without the electric field influence are analyzed by means of X-ray diffraction methods. [source] One-Year Prospective Three-Center Study Comparing the Outcome of a "Soft Bone Implant" (Prototype Mk IV) and the Standard Brånemark ImplantCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2003Bertil Friberg DDS ABSTRACT Background: Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry. Purpose: The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Branemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone. Materials and Methods: Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare, Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year. Results.: The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants. Conclusions: The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested. [source] Cancer as a consequence of the rising level of oxygen in the Late PrecambrianLETHAIA, Issue 3 2007JOHN M. SAUL The origin of multicelled animal life required collagen-family molecules whose own formation depended on the availability of molecular oxygen. Cancers, by contrast, are characterized by their low use of oxygen. In discussing the relationship between the origin of multicelled life and the origin of cancer, it is useful to think in terms of tissues rather than individual cells or complete animals. When animal tissues are disturbed, their constituent cells may be partially released from the constraints of multicellularity. This permits or obliges cells to reactivate anaerobic metabolic ways used by their single-celled ancestors in the oxygen-deficient Precambrian seas. Inhibition or loss of cell respiration under such circumstances may cause reversion to glycolytic fermentation, a less efficient metabolic style that generates waste products that are retained, thereby producing excess cell-growth. Distortion of tissue architecture may ensue with impairment of cell-to-cell adhesion, thereby liberating individual cells. Cells freed from tissue constraints undergo Darwinian variation which leads to loss of differentiation and produces cell types that are incompatible with the normal functioning of tissues. These steps, which may manifest themselves as carcinogenesis, are not reversible by restoration of oxygen and in effect constitute a demergence from the metazoan state. The existence of cancer among diverse phyla and especially among domesticated animals, suggests that the risk of cancer may be an initial condition of complex multicellular life and that it remains preferentially associated with newly modified designs. If so, there would be therapeutic strategies that have not yet been adequately considered. ,Cambrian explosion, cancer, cell differentiation, collagen, glycolysis, hard parts, metazoan origins. [source] | ||||||||||