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Case history of liner veneer instability
No full textABSTRACT: Construction conditions experienced during installation of a landfill geocomposite liner system led to two slides on a 3H:1V slope during construction. The landfill was being developed for final disposal of flue gas desulfurization by-product material (FGD). The slides occurred in two different areas of the 3H:1V slope and encompass 10,500 and 20,235 m 2 in the Fall of 1996 and Summer of 1997, respectively. The slides developed by movement along the PVC geomembrane/compacted clay liner interface during or shortly after placement of the protective FGD cover material over the drainage sand layer. Laboratory direct shear tests revealed that the shear strength of this interface is sensitive to the moisture content of the exposed compacted clay liner. The direct shear tests revealed reductions in the available shear strength of 35% and 37% for the peak and large displacement values as the compacted clay liner moisture content increased by 8 percentage points. In addition, shear stresses induced by surface traffic activities might result in shear displacements along the interface, which in some cases were large enough to lower the available shear resistance of the geomembrane/compacted clay interface to a post-peak or large displacement value. This paper discusses the slides, direct shear testing, slope stability analyses used to evaluate the mobilized interface shear strength parameters, the relationship between moisture content and geomembrane/compacted clay liner interface strength, and the effect of shear displacement on the mobilized shear strength
Investigation of Relationship Between Managerial Triple Skills and Staff's Performance of Red Crescent in Fars Province
No full textToday, managers should adopt various roles for success in performing of their duties and specific skills are needed to perform them. The need to inform these skills enough in managerial positions is the main challenges facing with managers. Given the importance of management performance and its effect on staffs' performance, the present study was performed based on investigation of relationships between triplet managerial skills and staff 's performance of Red Crescent in Fars Province. This study was a survey research and had been implemented in field. The statistical communities of the research were included 167 managers and 360 staffs on three levels of high, middle and operational and they were randomly selected using stratified random sampling method. The statistical samples based on Morgan table and sampling ratio were 116 managers and 186 employees. The number of 120 managers and 186 staffs were select to ensure more results. Reliability was calculated by SPSS Software. Then, the obtained results were analyzed by Pearson correlation analysis. The results showed that the assumptions of this study (there is a direct and significant correlation between triplet managerial skills and staff's performance of Red Crescent organization in Fars Province) were confirmed using Pearson correlation analysis at level of 95%. Considering the above, as managers have more skills (human, conceptual and technical) as a result, better performance of staffs will observe. So skill is considered as an integral part of management
Slađana ŽILIĆ, Vesna HADŽI-TAŠKOVIĆ ŠUKALOVIĆ, Vuk MAKSIMOVIĆ, Milan MAKSIMOVIĆ, Zorica BASIĆ, Vesna PERIĆ, Jelena DRAGIŠIĆ MAKSIMOVIĆ 46 th Croatian and 6 th International Symposium on Agriculture Antioxidant properties of soybean with black and yellow k
No full textAbstract The objectives of this study were to characterize black and yellow soybean varieties for the total phenolic, taninn, proanthocyanidin, flavonoid and tocopherol contents, and to examine antioxidant activity. Also, the content of tocopherols (α-, β-, γ-, and δ-) was detected by using HPLC method. The obtained results suggest that kernel extracts of black soybeans has considerable higher level of all the ivestigated phenolic classes and about double amount of the total phenolics. The total tocopherols were significantly higher in black than in yellow soybean varieties. Concentrations ranged from 264.3 to 266.7 μg/g and from 216.3 to 246.7 μg/g in black and yellow soybean varieties, respectively. β+γ-Tocopherol isomers were dominant in all samples. Correlation between total phenolics, phenolic classes, tocopherols and antioxidant activity detected by DPPH radical scavenging test, was found
Productivity of lexical categories in French-speaking children with cochlear implants. Brain Cogn 2003; 53
No full textAbstract The productivity of lexical categories was studied longitudinally in a sample of 17 young hearing-impaired French-speaking children with cochlear implants. Age of implantation ranged from 22 months to 76 months. Spontaneous speech samples were collected at six-month intervals over a period of 36 months, starting at the one-word stage. Four general measures of their linguistic production (number of utterances, verbal fluency, vocabulary, and grammatical production) as well as 36 specific lexical categories, according to the CHILDES codes, were computed in terms of tokens, i.e., total number of words. Cochlear-implanted children (CI) were compared to a French database of normally hearing children aged 2-4 compiled by the first author. Follow-up results indicate that, at the two-year post-implantation follow-up, noun, and verb morphology was significantly impaired. At the three-year followup, the cochlear-implanted group had recovered on adjectives, determiners and nouns, main verbs, and auxiliaries. The two groups differed significantly in processing locative adverbs, prepositions, pronouns, and verbs (infinitive verb, modal, and modal lexical), but individual variability within the cochlear-implanted group was substantial. Results are discussed in terms of recovery and developmental trends and variability in the acquisition of lexical categories by French children two years and three years post-implantation
Modeling the Revolving Revolution: The Debt Collection Channel
No full textAbstract We investigate the role of information technology (IT) in the collection of delinquent consumer debt. We argue that the widespread adoption of IT by the debt collection industry in the 1990s contributed to the observed expansion of risky lending to consumers, such as unsecured credit card lending. Our model stresses the role of private information about a delinquent borrower's solvency. The presence of private information implies that the costs of debt collection must be borne by lenders to sustain incentives to repay debt. IT is used to concentrate collection efforts on those delinquent borrowers who are more likely to repay
Aging Matters Addressing issues related to geropsychiatry and the well-being of older adults
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No full textMicrobial extracellular heteropolysaccharides are mainly linear molecules to which side chains of varying length and complexity are attached at regular intervals. Examination of 'families' of microbial exopolysacchaiide with closely related structures enables us to determine the effect of minor (or major) changes to structure on the physical properties of these macromolecules. Changes may also be seen in some of the biological properties of the polysaccharides, such as susceptibility to enzymes; interaction with antibodies or lectins; and capacity and specificity of ion binding. Acetyl groups frequently assert very marked effects on the properties of microbial polysaccharides. The presence or absence of an 0-acetyl or pyruvate (ketal) group on each oligosaccharide repeat unit can greatly alter the properties of a number of exopolysaccharides. Introduction Microbial extracellular heteropolysacchaides and especially those obtained from numerous bacterial species are generally considered to be of d o r m structure and are also frequently thought to be of fairly limited polydispersity. In many cases this belief may be correct, yet the methods used for the growth of the micro-organisms and the isolation of their extracellular products, may produce polymers with loss of some substituents or with material which has been to some extent degraded through chemical or biological action. In some preparations these alterations may have no sigdicant effect on the bulk properties of the polysaccharides, but in others sufficient changes may have occurred to cause marked alterations to their solution rheology and to other characteristics. The major dif€erences seen between these bacterial products and the plant polysaccharides which find such wide industrial applications lies in the lack of extensive branching in the microbial polymers, as they are composed of essentially linear molecules to which side chains of varying length and complexity are normally attached at regular intervals. Such sidschains are usually limited to mono-, di-, tri-or at most pentasaccharides and only rarely are they themselves branched. Through carehl control of culture conditions, through the use of enzymes or through use of mutants, it has proved possible to prepare microbial polysaccharides with altered structures. Mild chemical degradation procedures have also proved usefbl. It has also been noted that different microbial species or strains may produce a range of polysaccharides with close structural similarities. Examination of these diverse products provides several interesting 'families' of polysaccharide structures and enables us to determine the effect of minor (or major) changes to structure on the physical properties of these macromolecules. Such relatively minor merences may also greatly change the biological properties of the polysacchandes in respect to their susceptibility to enzymes or their interaction with antibodies or lectins, while a W e r property which may be altered is the capacity and specificity of ion binding. As well as differences in carbohydrate structure, the range of possible structures is M e r extended by the presence or absence of various acyl groups. Several homopolymers belonging to this group are available and provide an example of the effects which single p-D-glucosyl or j3-D-gentobiosyl side-chains confer on the linear macromolecule. Thus curdlan the linear molecule produced by several bacterial species is a unique polymer with interesting physical properties including a triple-helix conformation, but little biological activity. In contrast, scleroglucan and related fbgal polysaccharides canying the glucosyl side-chains have been widely claimed to belong to the group of macromolecules classified as 'biological response modiiiers' and inhibit tumorogenesis (ref 1). Equally curdlan forms gels in the absence of ions and shows interesting transitions at two different temperatures, while scleroglucan and related p-D-glucans, although yielding viscous aqueous solutions, do not form gels. An interesting new bacterial homopolysaccharide is the 1,4-P-linked poly-D-glucuronic acid produced by a mutant Rhizobium strain (refs. 2,3). This polymer has been the subject of a number of studies which have revealed some intriguing gelation properties similar to other polyuronic acids. Like bacterial alginates, the polymer is acetylated and the deacetylated product yielded a crystalline fibre pattern indicative of two-fold screw symmetry. It has been suggested that the high acetyl content of the native polymer promotes interchain as sociations and aggregate formation. As with bacterial alginates, the acetyl groups appear to inhibit junction zones in the presence of multivalent ions (ref 4). HeteroDolvsaccharides The simplest group of heteropolysaccharide structures are the galactoglucans produced by a very diverse group of bacteria. These polymers possess a disaccharide repeat unit together with acetyl, succinyl or pyruvate substituents. As yet, studies have been mainly conhed to structural determination rather than physical parameters, but they do provide a range of relatively simple structures in which the effects of various acyl groups may be studied.. xM6 and related KlebsiellalEnterobacter polvsaccharides A group of closely related structures are found in the polysaccharides of Enterobacter XM6, Klebsiella aerogenes serotype 54 and Escherichia coli serotype 27. In each case, the major structural repeat unit is a tetrasaccharide in which a glucosyl residue on the main-chain trisaccharide carries a monosaccharide substituent (ref 5 ) . In the E.coli polysaccharide this is a j3-D-galactosyl residue while in the other strains it is a j3-D-glucosyl residue. Three possible variants exist in the Klebsiella polymers -they may be nonacetylated, they may carry an 0-acetyl group on every alternate tetrasaccharide repeat unit, or they may have an acetyl group on each repeat unit, carried on the hcosyl residue (refs. 6,7). Surprisingly, all the polymers within this group can be hydrolysed by a polysaccharide depolymerase initially obtained fiom a bacteriophage lytic for one of the K. aerogenes type 54 strains (ref 8). This enzyme degrades all the substrates to tetrasaccharides or octasaccharides. The major differences in physical properties are seen when the effect of cations on the non-acetylated XM6 polysaccharide is examined. This polymer interacts with various monovalent and divalent cations to yield a very sharp sol-gel transition at a temperature of 3OoC with virtually no hysteresis ( ref 9). No gelation was observed with any of the other polysaccharides in this group -the acetylated Klebsiella products or the E.coli K27 polymer. However, alkaline treatment of the Klebsiella polysaccharides removed the 0-acetyl grou s and yielded products the behaviour of which mimicked that of xM6. Approximately 30% more Ca was bound to XM6 than to the monoacetylated Klebsiella polysaccharide (ref 10). Thus the presence of even one acetyl group on each alternate repeat unit was sutlicient to impede ion binding and prevent gelation. Fibre X-ray ditfraction clearly showed the similar helical structures in the XM6 and Klebsiella polymers and the inhibitory effect of the acetyl group on 0-2 of hcose residues on association between molecules (ref 11). Microbial exopolysaccharides 1913 Bacterial al-hates Although a number of bacterial species are capable of synthesising polysaccharides which can correctly be described as alginates, most work has been on EPS fiom Azotobacter vinelandii or Pseudomonas aeruginma, Pseudomonas fluorescens and Pseudomonas putida. The alginate fiom Azotobacter most closely resembles marine algal products, containing homopolymeric and mixed sequences of D-mannuronic and ~-guluronic acids and differing only in the presence of 0-acetyl groups on some D-mannuronosyl residues. Xanthan, the polysaccharide synthesised by most strains and pathovars of Xanthomonas campestris, has probably been studied more than any other bacterial exopolysaccharide. Even today, years after the initial structural studies of Jansson et al. (ref 14) and Melton et al. In the interaction between xanthan and locust bean gum, studies by Shatwell et al. (ref 26) revealed that the majority of xanthans tested formed a relatively strong gel network with LBG except in the case of a xanthan which was heady acetylated and very low in pyruvate. Deacetylation of this polymer significantly increased gel strength -G increasing by almost 250% (from 930 to 3300) and tan 6 fell. Xanthan defective in the terminal p-mannosyl side-chain residue formed a much weaker gel than any of the wild type gels tested and G was very low (620). From these results it was concluded that the presence of 0-acetyl groups had an inhibitory effect on copolymer gelation while the terminal manuose residue on the trisaccharide side-chain played an important role in the interaction between xanthan and LBG. This was recently supported by the finding in our laboratory, that acetan and LBG also form gels. However, these were much weaker than most xanthan-LBG interactions, resembling those of the polytetrasaccharide xanthan polymer BD9. The acetan was of comparable molecular mass to wild type xanthan, but the truncated xanthan material was almost certainly lower in mass. Thus the results for this material are not strictly comparable with the other values. Ojinnaka et al. (ref. 27) initially reported that deacetylation of acetan was necessary to achieve gelation with LBG and Konjac m a n , the glucose residues in the latter yielding stronger associations; later study did reveal weak interaction with the acetylated polysaccharide (V.J.Monis, personal communication). While the presence of the acetyl groups in acetan does not inhibit helix formation, deacetylation did stabilise the helical conformation. The role of side-chains in gelation induced by Cr3+ has also been studied (ref. 28). Partial acid hydrolysis was used remove the terminal mannose residues without significant reduction in molecular mass. The terminal p-D-mannOSe had little influence on such gelation and its removal, or the partial removal of the trisaccharide side-chains had minimal effects on gelation. Acetan did not show similar gelation unless sugars were removed from the side-chains by partial acid hydrolysis. It was therefore suggested that gelation resulted fiom interaction between the Cr3+ ions and glucuronic acid residues in which the longer and bulkier side-chains of acetan suppressed interaction through steric hindrance. Gellan The series of structures to which gellan, welan, rhamsan and other polysaccharides fiom Sphingomom spp. belong also provides examples of the effects of minor changes. Gellan only forms weak or rubbery gels unless the acyl groups are removed, most of the inhibitory effect being due to the L-glyceryl residues rather than the 0-acetyl groups which stick out from the helix and do not interfere with the packing arrangement stimulated by the presence of cations. Deacylated gellan yields hard and brittle gels which find applications for food and other uses. Commercial gellan preparations contained d c i e n t Ca2+ and Mg" to permit gelation, but conversion to the monovalent cation form yielded material which resembled alghates in their gelation when the monovalent ions were displaced by divalent ions (ref. 29). Gellan solutions with excess divalent cations present form iirm gels when cooled below the setting temperature and remelting proved dBcult (ref. 30). This behaviour contrasted with that found with gels formed in the presence of monovalent ions. Although other members of the gellan family of bacterial polysaccharides do not normally form gels, all possess double helical morphology despite the various substituents and side-chains present (ref. 31). However, unlike xanthan and acetan, the side-chains of welan promote the stability of 0 1997 IUPAC, Pure andApplied Chemistry69, [1911][1912][1913][1914][1915][1916][1917] 1916 I. W. SUTHERLAND the helix rather than interfering. Even rhamsan with its gentibiosyl side-chains adopts the double helix conformation. The helices cannot associate in exactly the same manner as in gellan and the high viscosity in solution may result from non-specific interactions between main chains and side-chains. The different side-chain structures found in the gellan family also greatly affect their susceptibility or resistance to various gellan lyases; the acyl groups present in native gellan are suflicient to cause almost complete inhibition of enzyme action, presumably through steric hindrance at the enzyme binding or catalytic site (ref 32). Thus, gellan and related polysaccharides with their structural similarities and complexities provide a further group of polysaccharides, the structure of which may show further subtle differences due to the presence of either acyl groups or substituent monosaccharides. As this group are of considerable commercial interest, they may well provide the main focus of interest in the 'post-~anthan' era
15+ MILLION TOP 1% MOST CITED SCIENTIST 12.2% AUTHORS AND EDITORS FROM TOP 500 UNIVERSITIES 10 Artificial Coordinating Field based Motion Planning of Mobile Robots
No full textDTA2012 Symposium: Combining Disaggregate Route Choice Estimation with Aggregate Calibration of a Dynamic Traffic Assignment Model
No full textAbstract Dynamic Traffic Assignment (DTA) models are important decision support tools for transportation planning and real-time traffic management. One of the biggest obstacles of applying DTA in large-scale networks is the calibration of model parameters, which is essential for the realistic replication of the traffic condition. This paper proposes a methodology for the simultaneous demand-supply DTA calibration based on both aggregate measurements and disaggregate route choice observations to improve the calibration accuracy. The calibration problem is formulated as a bi-level constrained optimization problem and an iterative solution algorithm is proposed. A case study in a highly congested urban area of Beijing using DynaMIT-P is conducted and the combined calibration method improves the fits to surveillance data compared to the calibration based on aggregate measurements only
Implementation and Use of a Direct, Partially Integral-Driven Non-Dyson Propagator Method for Molecular Ionization
No full textAbstract: The Green's function ADC(3) scheme has been for many years a successful method to predict theoretically the ionization (and electron affinity) spectrum of molecules. However, a dramatic enhancement of the method's power has come only recently, with the development of an approximation method to the one-particle Green's function which does not make direct use of the Dyson equation. In the present work, we present an efficient computer implementation of this novel approach, with first comparative tests demonstrating its enormous computational advantage over the conventional approach