863 resultados para Possible solutions


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Scaling methods allow a single solution to Richards' equation (RE) to suffice for numerous specific cases of water flow in unsaturated soils. During the past half-century, many such methods were developed for similar soils. In this paper, a new method is proposed for scaling RE for a wide range of dissimilar soils. Exponential-power (EP) functions are used to reduce the dependence of the scaled RE on the soil hydraulic properties. To evaluate the proposed method, the scaled RE was solved numerically considering two test cases: infiltration into relatively dry soils having initially uniform water content distributions, and gravity-dominant drainage occurring from initially wet soil profiles. Although the results for four texturally different soils ranging from sand to heavy clay (adopted from the UNSODA database) showed that the scaled solution were invariant for a wide range of flow conditions, slight deviations were observed when the soil profile was initially wet in the infiltration case or deeply wet in the drainage case. The invariance of the scaled RE makes it possible to generalize a single solution of RE to many dissimilar soils and conditions. Such a procedure reduces the numerical calculations and provides additional opportunities for solving the highly nonlinear RE for unsaturated water flow in soils.

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In this thesis some multivariate spectroscopic methods for the analysis of solutions are proposed. Spectroscopy and multivariate data analysis form a powerful combination for obtaining both quantitative and qualitative information and it is shown how spectroscopic techniques in combination with chemometric data evaluation can be used to obtain rapid, simple and efficient analytical methods. These spectroscopic methods consisting of spectroscopic analysis, a high level of automation and chemometric data evaluation can lead to analytical methods with a high analytical capacity, and for these methods, the term high-capacity analysis (HCA) is suggested. It is further shown how chemometric evaluation of the multivariate data in chromatographic analyses decreases the need for baseline separation. The thesis is based on six papers and the chemometric tools used are experimental design, principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), partial least squares regression (PLS) and parallel factor analysis (PARAFAC). The analytical techniques utilised are scanning ultraviolet-visible (UV-Vis) spectroscopy, diode array detection (DAD) used in non-column chromatographic diode array UV spectroscopy, high-performance liquid chromatography with diode array detection (HPLC-DAD) and fluorescence spectroscopy. The methods proposed are exemplified in the analysis of pharmaceutical solutions and serum proteins. In Paper I a method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of UV-Vis spectroscopy, orthogonal signal correction and multivariate calibration with PLS and SIMCA classification. Paper II proposes a new method for the rapid determination of pharmaceutical solutions by the use of non-column chromatographic diode array UV spectroscopy, i.e. a conventional HPLC-DAD system without any chromatographic column connected. In Paper III an investigation is made of the ability of a control sample, of known content and identity to diagnose and correct errors in multivariate predictions something that together with use of multivariate residuals can make it possible to use the same calibration model over time. In Paper IV a method is proposed for simultaneous determination of serum proteins with fluorescence spectroscopy and multivariate calibration. Paper V proposes a method for the determination of chromatographic peak purity by means of PCA of HPLC-DAD data. In Paper VI PARAFAC is applied for the decomposition of DAD data of some partially separated peaks into the pure chromatographic, spectral and concentration profiles.

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In this work the surface layer formation in polymer melts and in polymer solutions have been investigated with the atomic force microscope (AFM). In polymer melts, the formation of an immobile surface layer results in a steric repulsion, which can be measured by the AFM. From former work it is know, that polydimethyl siloxane (PDMS) forms a stable surface layer for molecular weights above 12 kDa. In the present thesis, polyisoprene (PI) was investigated apart from PDMS, by a)measuring the steric surface interactions and b)measuring the surface slip in hydrodynamic experiments. If a polymer flows over a surface, the flow velocity at the surface is larger then zero. If case of a surface layer formation the flow plane changes to the top of the adsorbed layer and the surface slip is reduced to zero. By measuring the surface slip in hydrodynamic experiments, it is therefore possible to determine the presence of a stable surface layer. The results show no stable repulsion for PI and only a small decrease of the surface slip. This indicates that PI does not form a stable surface layer, but is only adsorbed weakly to the surface. Furthermore for 8 kDa PDMS the timescale of the formation of a surface layer was investigated by changing themaximal force the tip applied to the surface. With a repulsive force present, applying a higher force than 15 nN resulted in a destruction of the surface layer, indicated by attractive forces. Reducing the applied force below 15 nN then resulted in an increase of the repulsion to the former state during one minute, thus indicating that a surface layer can be formed within one minute even under the influence of continuous measurements. As a next step, mixtures of two PDMS homopolymers with different chain lengths have been investigated. The aim was to verify theoretical predictions that shorter chains should predominate at the surface due to their smaller loss in conformational entropy. The measurements where done in dependence of the volume fractions of short and long chain PMDS. The results confirmed the short chain dominance for all mixtures with less then 90 vol.% long chain PDMS. Surface layer formation in solution was investigated for superplasticizers which are industrially used as an additive to cement. They change the surface interaction between the cement grains from attractive to repulsive and the freshlymixed cement paste therefore becomes liquid. The aimin this part of the thesis was, to investigate cement particle interactions in a close to real environment. Therefore calcium silicate hydrate phases have been precipitated onto an AFM tip and onto a calcite crystal and the interaction between these surfaces have beenmeasured with and without addition of superplasticizers. The measurements confirmed the change from attraction to repulsion upon addition of superplasticizers. The repulsive steric interaction increased with the length of the sidechain of the superplasticizer, and the dependence of the range of the steric interactions on the sidechain length indicated that the sidechains are in a coiled conformation.

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Studies have depicted that the rate of unused patents comprises a high portion of patents in North America, Europe and Japan. Particularly, studies have identified a considerable share of strategic patents which are left unused due to pure strategic reasons. While such patents might generate strategic rents to their owner, they may have harmful consequences for the society if by blocking alternative solutions that other inventions provide they hamper the possibility of better solutions. Accordingly, the importance of the issue of nonuse is highlighted within the literature on strategic patenting, IPR policy and innovation economics. Moreover, the current literature has emphasized on the role of patent pools in dealing with potential issues such as excessive transaction cost caused by patent thickets and blocking patents. In fact, patent pools have emerged as policy tools facilitating technology commercialization and alleviating patent litigation among rivals holding overlapping IPRs. In this dissertation I provide a critical literature review on strategic patenting, identify present gaps and discuss some future research paths. Moreover, I investigate the drivers of strategic non-use of patents with particular focus on unused strategic play patents. Finally, I examine if participation intensity in patent pools by pool members explains their willingness to use their non-pooled patents. I also investigate which characteristics of the patent pools are associated to the willingness to use non-pooled patents through pool participation. I show that technological uncertainty and technological complexity are two technology environment factors that drive unused play patents. I also show that pool members participating more intensively in patent pools are more likely to be willing to use their non-pooled patents through pool participation. I further depict that pool licensors are more likely to be willing to use their non-pooled patents by participating in pools with higher level of technological complementarity to their own technology.

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The present paper is the result of a four-year-long project examining the concept and the policies of cultural diversity and the impact of digital media upon the regulatory environment where the goal of cultural diversity is to be achieved. The focus of the project was primarily on the international level and in particular on the World Trade Organization (WTO) and the United Nations Educational Scientific and Cultural Organization (UNESCO), which also epitomise the often framed as opposing pair of trade and culture. In the broad context of the project, we sought to pinpoint the essential elements of an international trade-and-culture conducive framework that can also overcome the existing fragmentation in the field of international law and move towards more coherent solutions. In a narrower context, we sketched some possible improvements to the WTO law that can make it more suitable to the digital networked environment and to the objective of diverse media that some states aspire. . Our key messages are: (1) Neither the WTO nor UNESCO currently offers appropriate solutions to the trade and culture predicament and allows for efficient protection and promotion of cultural diversity; (2) The trade and culture discourse is overly politicised and due to the related path dependencies, a number of feasible solutions appears presently blocked; (3) The digital networked environment has profoundly changed the ways cultural content is created, distributed, accessed and consumed, and may thus offer good reasons to reassess and readjust the present models of governance; (4) Access to information appears to be the most appropriate focus of the discussions with view to protecting and promoting cultural diversity in the new digital media setting, both in local and global contexts; (5) This new focal point demands also broadening and interconnecting the policy discussions, which should go beyond the narrow scope of audiovisual media services, but cautiously account for the developments at the network and applications levels, as well as in other domains, such as most notably intellectual property rights protection; (6) There are various ways in which the WTO can be made more conducive to cultural policy considerations and these include, among others, improved and updated services classifications; enhanced legal certainty with regard to digitally transferred goods and services; incorporation of rules on subsidies for services and on competition.

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BACKGROUND Intravenous fluids are commonly prescribed in childhood. 0.9 % saline is the most-used fluid in pediatrics as resuscitation or maintenance solution. Experimental studies and observations in adults suggest that 0.9 % saline is a poor candidate for fluid resuscitation. Although anesthesiologists, intensive care specialists, perioperative physicians and nephrologists have been the most active in this debate, this issue deserves some physiopathological considerations also among pediatricians. RESULTS As compared with so-called "balanced" salt crystalloids such as lactated Ringer, administration of large volumes of 0.9 % saline has been associated with following deleterious effects: tendency to hyperchloremic metabolic acidosis (called dilution acidosis); acute kidney injury with reduced urine output and salt retention; damaged vascular permeability and stiffness, increase in proinflammatory mediators; detrimental effect on coagulation with tendency to blood loss; detrimental gastrointestinal perfusion and function; possible uneasiness at the bedside resulting in unnecessary administration of more fluids. Nevertheless, there is no firm evidence that these adverse effects are clinically relevant. CONCLUSIONS Intravenous fluid therapy is a medicine like insulin, chemotherapy or antibiotics. Prescribing fluids should fit the child's history and condition, consider the right dose at the right rate as well as the electrolyte levels and other laboratory variables. It is unlikely that a single type of fluid will be suitable for all pediatric patients. "Balanced" salt crystalloids, although more expensive, should be preferred for volume resuscitation, maintenance and perioperatively. Lactated Ringer appears unsuitable for patients at risk for brain edema and for those with overt or latent chloride-deficiency. Finally, in pediatrics there is a need for new fluids to be developed on the basis of a better understanding of the physiology and to be tested in well-designed trials.

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In this work we present results of zinc diffusion in GaAs using the liquid phase epitaxy technique from liquid solutions of Ga‐As‐Zn and Ga‐As‐Al‐Zn. Using silicon‐doped n‐GaAs substrates, working at a diffusion temperature of 850 °C, and introducing a dopant concentration ranging 1018–1019 cm−3, the most important findings regarding the diffusion properties are as follows: (a) zinc concentration in the solid depends on the square root of zinc atomic fraction in the liquid; (b) the diffusion is dominated by the interstitial‐substitutional process; (c) the diffusivity D varies as about C3 in the form D=2.9×10−67C3.05; (d) aluminum plays the role of the catalyst of the diffusion process, if it is introduced in the liquid solution, since it is found that D varies as (γAsXlAs)−1; (e) the zinc interstitial is mainly doubly ionized (Zn++i); (f) the zinc diffusion coefficient in Al0.85 Ga0.15 As is about four times greater than in GaAs; (g) by means of all these results, it is possible to control zinc diffusion processes in order to obtain optimized depth junctions and doping levels in semiconductor device fabrication.

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Three different oils: babassu, coconut and palm kernel have been transesterified with methanol. The fatty acid methyl esters (FAME) have been subjected to vacuum fractional distillation, and the low boiling point fractions have been blended with fossil kerosene at three different proportions: 5, 10 and 20% vol.

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A novel thermodynamic approach to the reversible unfolding of proteins in aqueous urea solutions has been developed based on the premise that urea ligands are bound cooperatively to the macromolecule. When successive stoichiometric binding constants have values larger than expected from statistical effects, an equation for moles of bound urea can be derived that contains imaginary terms. For a very steep unfolding curve, one can then show that the fraction of protein unfolded, B̄, depends on the square of the urea concentration, U, and is given by \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}\bar {B}=\frac{{\mathit{A}}^{{\mathit{2}}}_{{\mathit{1}}}{\mathit{e}}^{{\mathrm{{\lambda}}}n\bar {B}}{\mathit{U}}^{{\mathit{2}}}}{{\mathrm{1\hspace{.167em}+\hspace{.167em}}}{\mathit{A}}^{{\mathrm{2}}}_{{\mathrm{1}}}{\mathit{e}}^{{\mathrm{{\lambda}}}\bar {B}}{\mathit{U}}^{{\mathrm{2}}}}{\mathrm{.}}\end{equation*}\end{document} A12 is the binding constant as B̄→ 0, and λ is a parameter that reflects the augmentation in affinities of protein for urea as the moles bound increases to the saturation number, n. This equation provides an analytic expression that reproduces the unfolding curve with good precision, suggests a simple linear graphical procedure for evaluating A12 and λ, and leads to the appropriate standard free energy changes. The calculated ΔG° values reflect the coupling of urea binding with unfolding of the protein. Some possible implications of this analysis to protein folding in vivo are described.

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Amphipols are a new class of surfactants that make it possible to handle membrane proteins in detergent-free aqueous solution as though they were soluble proteins. The strongly hydrophilic backbone of these polymers is grafted with hydrophobic chains, making them amphiphilic. Amphipols are able to stabilize in aqueous solution under their native state four well-characterized integral membrane proteins: (i) bacteriorhodopsin, (ii) a bacterial photosynthetic reaction center, (iii) cytochrome b6f, and (iv) matrix porin.

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In this paper we examine multi-objective linear programming problems in the face of data uncertainty both in the objective function and the constraints. First, we derive a formula for the radius of robust feasibility guaranteeing constraint feasibility for all possible scenarios within a specified uncertainty set under affine data parametrization. We then present numerically tractable optimality conditions for minmax robust weakly efficient solutions, i.e., the weakly efficient solutions of the robust counterpart. We also consider highly robust weakly efficient solutions, i.e., robust feasible solutions which are weakly efficient for any possible instance of the objective matrix within a specified uncertainty set, providing lower bounds for the radius of highly robust efficiency guaranteeing the existence of this type of solutions under affine and rank-1 objective data uncertainty. Finally, we provide numerically tractable optimality conditions for highly robust weakly efficient solutions.

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This article examines why, how, and with what results have judicial councils spread under the influence of European institutions throughout Central and Eastern Europe in the course of the last twenty years. It first traces back how the judicial councils, themselves just one possible form of administration of courts, have emerged as the recommended universal solution Europe-wide and internationally. Second, it discusses how has this model been exported under the patronage of European and international institutions to transition countries in Central and Eastern Europe. Assessing, thirdly, the reality of the functioning of such new judicial councils in these countries, in particular in Slovakia and Hungary, with the Czech Republic without a judicial council providing a counter-example, it is suggested that their impact on further judicial and legal transition has been either questionable or outright disastrous. This brings, eventually, into question the legitimacy as well as the bare reasonableness of the entire process of European/international standards setting and their later marketing or in reality rather imposition onto the countries in transition.

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Fifty oil soluble amines were screened for possible use as extractants for uranium from sulfuric acid solutions. The most promising of these were studied further to obtain the optimum conditions for operation of such a process. Kerosene was used as the diluent.

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In this paper we demonstrate that it is possible to gradually improve the performance of support vector machine (SVM) classifiers by using a genetic algorithm to select a sequence of training subsets from the available data. Performance improvement is possible because the SVM solution generally lies some distance away from the Bayes optimal in the space of learning parameters. We illustrate performance improvements on a number of benchmark data sets.

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A study was conducted in the UK, as part of the New Dynamics of Ageing Working Late project, of the journey to work among 1215 older workers (age groups 45-49, 50-55, 56-60 and 60 + ). The aim was to identify problems or concerns that they might have with their commute, strategies that have been adopted to address them, and the role that employers can play to assist them. Follow-up interviews with 36 employees identified many strategies for assisting with the problems of journeys to work, ranging from car share and using public transport to flexible working and working some days from home. Further interviews with a sample of 12 mainly larger companies showed that employers feel a responsibility for their workers’ commute, with some offering schemes to assist them, such as adjusting work shift timings to facilitate easier parking. The research suggests that the journey to work presents difficulties for a significant minority of those aged over 45, including issues with cost, stress, health, fatigue and journey time. It may be possible to reduce the impact of these difficulties on employee decisions to change jobs or retire by assisting them to adopt mitigating strategies. It does not appear that the likelihood of experiencing a problem with the journey to work increases as the employee approaches retirement; therefore, any mitigating strategy is likely to help employees of all ages. These strategies have been disseminated to a wider audience through an online resource at www.workinglate.org.