Bare Form Research Articles

A Promising Alternative to PEMFC Graphite Bipolar Plates: Surface Modified Type 304 Stainless Steel with TiN Nanoparticles and Elastic Styrene Butadiene Rubber Particles

AbstractIn order to utilise inexpensive bipolar plates for proton exchange membrane fuel cells (PEMFC), a surface modification with TiN nanoparticles and elastic styrene butadiene rubber (SBR) particles has been applied to the most widely commercialised stainless steel of type 304 which did not satisfy the required properties in the bare form. The electro‐conducting agglomerates were electrophoretically deposited on the stainless steel bipolar plates. The surface modification greatly improved the corrosion resistance of the stainless steel as well as the interfacial contact resistance (ICR). As a result, the cell performance was significantly enhanced and become comparable to that with graphite bipolar plate during operation for 1,000 h. Ac‐impedance results indicated that the TiN–SBR coating was effective not only in reducing the ICR but also in retaining the resistance low throughout the operation. The hydrophobic character of the TiN–SBR coating on the stainless steel bipolar plates, which facilitated the removal of the formed water in the cathode side during the single cell operation, is also responsible for the enhanced cell performance. Therefore, the type 304 stainless steel bipolar plate modified with the electro‐conducting nanosized TiN – elastic SBR particles is suggested to be a promising substituent for the PEMFC graphite bipolar plate.

In-vivo tumor targeting of pluronic-based nano-carriers

Pluronic-based nano-carriers including bare forms that were composed of Pluronic F 68(NC(PF 68)) or Pluronic F 127(NC(PF 127)), and chitosan-conjugated forms (Chito-NC(PF 68) or Chito-NC(PF 127)) were prepared by photo-polymerizing two kinds of diacrylated Pluronic (F 68 and F 127) and acrylated chitosan to investigate the effect of chitosan conjugation and their physicochemical characteristics (size and hydrophilicity) of Pluronic-based nano-carriers on the tumor targeting efficiency. All of the nano-carriers were stable in serum-containing media without forming any aggregation and did not show any acute cytotoxicity to both normal (NIH3T3 fibroblast) and tumor (SCC7) cells. Chitosan conjugation did not change their sizes or thermo-sensitive properties of the nano-carriers, but significantly increased their in-vitro cellular uptake compared to the corresponding bare forms. The in-vivo tumor accumulation of these nano-carriers was optically monitored by using Cy5.5-attached nano-carriers in SCC7 tumor-bearing mice. For all cases, local accumulation of the injected nano-carriers in liver was not dominant compared to the tumor site, demonstrating good tumor targeting efficacy of the Pluronic-based nano-carriers. Among different samples, chitosan-conjugated nano-carriers showed much better tumor accumulation than bare forms, and mostly remained up to 72 h, implying prolonged blood circulation and more efficient tumor accumulation. Between Chito-NC(PF 68) and Chito-NC(PF 127), Chito-NC(PF 68) showed a little better tumor accumulation and retention, suggesting the difference in Pluronic, thus difference in hydrophilicity and the size of the nano-carriers also might affect the tumor targeting. In contrast, bare nano-carriers were initially accumulated well in tumor, but they were excreted from the tumor site relatively rapidly. Therefore, chitosan-functionalization was very effective for improving the tumor targeting efficacy of Pluronic-based nano-carriers.

A versatile scanning acoustic platform

We present a versatile and highly configurable scanning acoustic platform. This platform, comprising a high frequency transducer, bespoke positioning system and temperature-regulated sample unit, enables the acoustic probing of materials over a wide range of length scales and with minimal thermal aberration. In its bare form the platform acts as a reflection-mode acoustic microscope, while optical capabilities are readily incorporated to extend its abilities to the acousto-optic domain. Here we illustrate the capabilities of the platform through its incarnation as an acoustic microscope. Operating at 55 MHz we demonstrate acoustic imaging with a lateral resolution of 25 µm. We outline its construction, calibration and capabilities as an acoustic microscope, and discuss its wider applications.

Variation of Ergativity Patterns in Indo-Aryan

Dialects which are very often classified under the rubric ‘Hindi’ display various ergativity patterns. It has been noticed that some of them violate the universals formulated in the late 1970s regarding morphology and agreement in the ergative construction (Comrie 1978, Trask 1979). The recent studies on agreement in Hindi and its varieties have shown at least two major types of agreement in the perfective tenses based on the bare participial form, i.e. single and double agreement (Das 2006).

Semantics of Slavic anaphoric possessive determiners

No abstract.

Investigation of Reverse-Hydrogen Spillover on Zeolite-Supported Palladium Tetramer by ONIOM Method

The present study explores favorable chemical state of zeolite-supported Pd4 clusters using the ONIOM (our-own-N-layered integrated molecular orbital + molecular mechanics) approach, as implemented in the Gaussian03 code. Lowest-energy structures of Pd4 in the gas phase as well as on a zeolite support are found to be in the triplet state. The calculations reveal that reverse hydrogen spillover from bridging OH groups of zeolite support onto Pd4 results in a hydrogenated Pd4H/Zeo((m − 1)H), m = 1−3 species, which are energetically preferable over the bare zeolite-supported form of Pd4/Zeo(mH). The process of single hydrogen transfer from the zeolite support to the Pd4 cluster is found to be exothermic and more favorable than two- and three-proton transfer processes.

Effects of microsolvation and aqueous solvation on the tautomers of histidine: a computational study on energy, structure and IR spectrum

Microsolvation and combined microsolvation-continuum approaches are employed to investigate the structures and energies of canonical and zwitterionic histidine conformers. The effect of hydration on the relative conformational stability is examined. The strategy of exploring singly and doubly hydrated structures and the possible microsolvation patterns are described. We find that bonding water molecule may significantly change the relative conformational stabilities. In gas phase, the singly and doubly hydrated canonical forms are more stable than their zwitterionic counterparts. In solution, the continuum solvent model shows that bare zwitterionic form is more stable than bare canonical form by 1.1 kcal/mol. This energy separation is increased to 2.2 and 3.4 kcal/mol with inclusion of one and two explicit water molecules, respectively. We have also observed that the doubly hydrated structures obtained by combining two water molecules simultaneously to the solute molecule are preferred over the stepwise hydration. Hydrogen bond energies for the most stable hydrated histidine tautomers are determined by the atoms in molecules theory. The infrared (IR) spectra for the most stable singly and doubly hydrated structures of both histidine tautomers in gas phase are characterized. The stretching frequencies for NH of imidazole ring and OH of COOH are red shifted due to the hydrations. The IR spectra for the most stable zwitterionic tautomers in solution are also presented and discussed in connection with the comparison to the experiments. The pKa values obtained for the ring protonated zwitterions with two explicit water molecules appear to be in good agreement with the experiments.

Hydrogen adsorption on model tungsten carbide surfaces

The potential of tungsten carbide to replace platinum as an anode electrocatalyst has attracted considerable attention due to its activity towards hydrogen oxidation, passivity in acidic electrolyte, and resistance to carbon monoxide poisoning. As a first step towards understanding the mechanisms underlying these qualities, we have performed density functional calculations on slab models of the tungsten carbide surface. We have calculated the adsorption energies of hydrogen on the different available bonding sites, and made a comparison to known values for platinum. The variation of bond strength with surface coverage has been investigated, and used to construct model surface Pourbaix diagrams. The nature and structure of the passivated surface is still an open question. It is possible that the tungsten dissolves out of the top-most surface layers, leaving a surface enriched in carbon. We have studied the effect of additional layers of carbon on the adsorption behaviour of hydrogen. While the most stable surface in its bare form provides binding sites that adsorb carbon with an energy of around 4.0 eV, about 60% higher than the adsorption energy of hydrogen on platinum, a carbonaceous tungsten carbide surface provides a maximum binding energy of 2.49–2.69 eV, much closer to the optimum value for efficient catalysis.

Long-term performance of zeolite Na A-X blend as backfill material in near surface disposal vault

This study investigates the feasibility of using synthetic zeolite Na A-X blend prepared from fly ash as near surface disposal backfill material. Tests were conducted at laboratory scale to evaluate the physical and chemical properties of the prepared zeolite. The zeolite density, porosity, and particle size distribution were measured. The distribution coefficient (Kd) value of Cs ions was evaluated using batch sorption experiment in synthetic groundwater to simulate possible conditions for near surface disposal. The transient behavior of the batch sorption experimental data were analyzed using Lagergren, Ho and Mckay, and Morris–Weber rate models to assess the controlling mechanism of the sorption process. It was found that the sorption process is chemisorption and controlled by diffusion mechanism. The dispersional behavior of Cs ions on the prepared material was studied using column experiment and the hydrodynamic dispersion coefficient was determined. To provide an overall functional performance of the proposed backfill material, the long-term behavior of the prepared zeolite has been evaluated using computer model. This model consists of two modules that has been developed to study the migration of Cs radionuclides from bare cementitious waste form through the backfill. The study compares the release rate from bentonite–crushed rock mixture to that from the prepared zeolite. The result demonstrates that synthetic zeolite Na A-X blend shows a better performance in terms of radionuclide containment.

An Experimental Syntactic Study of Binding of Multiple Anaphors in Korean

In this paper we investigated the binding behavior of three Korean reflexives-caki, casin, and caki-casin-through a Truth Value Judgment Task with pictures and found that while caki and caki-casin pattern as claimed in the theoretical literature, as a long-distance and a local anaphor respectively, native Korean speakers differ in how they treat casin. While the speakers as a group treat casin as an LDA, individual results revealed a bimodal distribution, with one group of speakers consistently treating casin as an LDA and another, smaller, group consistently treating it as a local anaphor. This distribution is puzzling in that the grammar of speakers who treat casin as a strictly local anaphor appears to violate the cross-linguistic generalization that morphologically simple reflexives are long-distance anaphors. We show that this problem is only apparent, since the bare form casin lends itself to two different structural analyses. In addition, we show that the greater percentage of speakers who treat casin as an LDA reflects an ongoing change in the grammar of Korean, where casin is both increasing in frequency and taking on more long distance antecedents. This assessment is supported by the sociolinguistic profiles of speakers we tested as well as the frequency and distribution of casin in Bible translations.

Reexamination of the Bare Preterite Base in the Jewish Neo-Aramaic Dialect of Zakho

AbstractIn Neo-Aramaic dialects the historic passive participle is used as the base form for the preterite tense. Nonetheless, the scholarly tradition saw it as a passive form, especially when it appears alone as a 'bare form'. A wide corpus study of Jewish Zakho Neo-Aramaic shows, however, that in some cases it is justified to see this form as bearing an active function. This is established through the examination of the information-structure associated with the form. A comparison to an older stratum of Neo-Aramaic, namely the Nerwa texts from the 17th century, provides a possible diachronic explanation of this change.

Reverse Hydrogen Spillover onto Zeolite-Supported Metal Clusters: An Embedded Cluster Density Functional Study of Models M6(M = Rh, Ir, or Au)

A density functional study using isolated cluster models of the zeolite framework (Vayssilov, G. N.; Rosch, N. Phys. Chem. Chem. Phys. 2005, 7, 4019) on supported metal clusters M6/zeo in a hydroxylated faujasite cage showed that for 12 metals M of the groups 8−11 the hydrogenated state, M6(3H)/zeo, is energetically preferred over the bare form M6/zeo(3H). The former state was obtained as result of reverse hydrogen spillover from zeolite OH groups onto the metal particle. In the present work, we reinvestigated this problem of identifying the favorable chemical state of zeolite-supported metal species for selected M6 model clusters (M = Rh, Ir, or Au) using an accurate quantum mechanics/molecular mechanics (QM/MM) approach where a QM partition is embedded in an extended zeolite lattice (MM). The embedding method covEPE, an improved variant of the elastic polarizable environment model EPE, adapted for polar-covalent materials, properly accounts for both the mechanical rigidity of the zeolite framework and t...

Articulatory characteristics of Hungarian ‘transparent’ vowels

Using a combination of magnetometry and ultrasound, we examined the articulatory characteristics of the so-called ‘transparent’ vowels [iː], [i], and [eː] in Hungarian vowel harmony. Phonologically, transparent vowels are front, but they can be followed by either front or back suffixes. However, a finer look reveals an underlying phonetic coherence in two respects. First, transparent vowels in back harmony contexts show a less advanced (more retracted) tongue body posture than phonemically identical vowels in front harmony contexts: e.g. [i] in buli-val is less advanced than [i] in bili-vel. Second, transparent vowels in monosyllabic stems selecting back suffixes are also less advanced than phonemically identical vowels in stems selecting front suffixes: e.g. [iː] in ír, taking back suffixes, compared to [iː] of hír, taking front suffixes, is less advanced when these stems are produced in bare form (no suffixes). We thus argue that the phonetic degree of tongue body horizontal position correlates with the phonological alternation in suffixes. A hypothesis that emerges from this work is that a plausible phonetic basis for transparency can be found in quantal characteristics of the relation between articulation and acoustics of transparent vowels. More broadly, the proposal is that the phonology of transparent vowels is better understood when their phonological patterning is studied together with their articulatory and acoustic characteristics.

πN scattering and γN → Nπ photoproduction within the unitary improved Born approximation

Following the programme of describing consistently several processes where the isobar Δ(1232 MeV) nucleon resonance appears as an intermediate state, in this work we propose to unitarize our old improved Born approximation already used to describe successfully π+p elastic and radiative scattering, to treat pion photoproduction. First we add the effect of final state interactions and make a new determination of the mass, width and the coupling constant to the pion–nucleon state of the Δ resonance. Then extending the model for pion photoproduction and using the resonance parameters determined previously, we are able to define effective form factors (at k2γ = 0) for the γN → Δ vertex with values GM = 2.97 ± 0.08 and GE = 0.055 ± 0.010, by fitting the data for the M3/21+ and E3/21+ multipoles. These values are fully consistent with recent chiral effective field theory calculations, and using them we can predict satisfactorily the data for other multipoles and the photoproduction cross section. Finally, we intend a model-independent determination of the bare form factors making a dynamical dressing of the vertex, getting G0M = 1.69 ± 0.02, G0E = 0.028 ± 0.008 and R0EM = −1.67 ± 0.45%, which are compared with different quark models.

A consistent dynamical model for pion-photoproduction

Abstract Pion-photoproduction amplitude is calculated within a consistent isobar model already used to fix the Δ + + ( 1232 MeV ) parameters in pion–nucleon scattering and bremsstrahlung. This amplitude is expressed in terms of (physical) on-shell quantities and off-shell contributions coming from final state interactions. These latter are isolated in principal value integrals on the non-polar part of the pion–nucleon K -matrix, being the main effect of them to dress the bare form factors present in the γ N → Δ vertex. First, we hide the dressing into effective form factors getting at k γ 2 = 0 , G M = 2.97 ± 0.08 and G E = 0.055 ± 0.010 in full consistence with recent chiral effective field theory calculations. Then, different models to regularize the mentioned integrals are analyzed. We choose those better describing the non-resonant multipoles, in order to get model independent results for the resonant ones. Finally, we try to predict the bare form factors getting G M 0 = 1.69 ± 0.02 and G E 0 = 0.028 ± 0.008 , which are consistent with recent lattice quark calculations and other more sophisticated dynamical models.

Acoustic correlates of inflectional morphology in the speech of children with specific language impairment and their typically developing peers

The development of the use of the third‐person singular –s in open syllable verbs in children with specific language impairment (SLI) and their typically developing peers was examined. Verbs that included overt productions of the third‐person singular –s morpheme (e.g. Bobby plays ball everyday; Bear laughs when mommy buys popcorn) were contrasted with clearly bare stem contexts (e.g. Mommy, buy popcorn; I saw Bobby play ball) on both global and local measures of acoustic duration. A durational signature for verbs inflected with ‐s was identified separately from factors related to sentence length. These duration measures were also used to identify acoustic changes related to the omission of the –s morpheme. The omitted productions from the children with SLI were significantly longer than their correct third‐person singular and bare stem productions. This result was unexpected given that the omitted productions have fewer phonemes than correctly inflected productions. Typically developing children did not show the same pattern, instead producing omitted productions that patterned most closely with bare stem forms. These results are discussed in relation to current theoretical approaches to SLI, with an emphasis on performance and speech‐motor accounts.

The impact of phonological complexity on past tense inflection in children with Grammatical-SLI

English-speaking children with Specific Language Impairment (SLI) variably produce inflected and bare stem forms in obligatory past tense contexts. Researchers have not reached consensus as to whether the underlying deficit is morphosyntactic or morphophonological in nature. The Computational Grammatical Complexity (CGC) Hypothesis takes a different tack: it hypothesizes that for children with a particular form of SLI, Grammatical-SLI, the deficit is in representing linguistic structural complexity in at least three components of the computational grammatical system – syntax, morphology and phonology. Deficits in all these components are predicted to impact on regular past tense formation. The impact of syntactic and morphological complexity on G-SLI children's realization of tense has been tested previously. Here we complete the picture by considering phonological effects on their production of regular past tense inflection. Using a past tense elicitation task where we manipulate the phonological complex...

The Morpho-Phonological Interfacein Specific Language Impairment

This thesis investigates the nature of the interface between two components of language-morphology and phonology-in English-speaking children with grammatical-specific language impairment (G-SLI) compared to those with typi cally developing language. Children with G-SLI have previously been shown to be impaired in forming and comprehending syntactically complex structures (e.g., passives, pronominal binding). They also have the past-tense deficit that is char acteristic of SLI in English, producing bare stem forms in obligatory past-tense contexts (van der Lely (1998), van der Lely and Ullman (2001)). This is despite nonverbal abilities in the normal range and an absence of hearing, auditory proc essing, or articulatory deficits that could account for the language deficit (van der Lely, Rosen, and Adlard (2004)). To date, however, phonological skills in G-SLI children have not been investigated. Furthermore, the past-tense deficit, inter preted by van der Lely and Ullman as an impairment in using a suffixation rule, has been interpreted by other authors as having a phonological basis (e.g., Joanisse and Seidenberg (1998)). In this thesis I investigate the nature of the phonological deficit in G-SLI and establish that phonology does indeed impact on past-tense inflection but that this is in addition to specific deficits in syntax and inflectional morphology. G-SLI children between 9 and 16 years old were compared to typically developing chil dren between 4 and 12 years old. In a set of experiments I show the following for G-SLI children:

Is There Pasif Semu in Jakarta Indonesian?

This paper examines whether pasif semu (P2), one of two passives in Standard Indonesian, exists in Jakarta Indonesian. In P2 in Standard Indonesian the verb appears in bare stem form, the theme has been promoted to surface subject, but—unlike European-style passives—the actor has not been demoted to adjunct. This is to be contrasted with the di-passive (P1), in which di- is prefixed to the verb, the theme is promoted to surface subject, and the agent is demoted to adjunct. Standard Indonesian is to a large extent an artificial language, the creation of language planners rather than of its speakers. In contrast, Jakarta Indonesian is the native language of the natives of Jakarta, and, through the influence of TV, movies, and radio, is heard with ever greater frequency throughout Indonesia. In our study (drawn from a variety of corpora), a clear contrast is seen between child and child directed speech, on the one hand, and adult to adult speech, on the other. P2 is essentially nonexistent in the former but exists robustly in the latter. We argue that child speech and child directed adult speech represent basilectal Jakarta Indonesian, in which P2 has been lost, and that the adult to adult corpora represent a mesolectal variety of Jakarta Indonesian that shows a number of influences from Standard Indonesian not found in the child and child directed corpora.

On the Interaction of Bare and Hydrated Aluminum Ion with Nucleic Acid Bases (U, T, C, A, G) and Monophosphate Nucleotides (UMP, dTMP, dCMP, dAMP, dGMP)

The B3LYP/6-311+G(2df,2p) density functional approach was used to study the interaction that aluminum trication, in the bare and hydrated forms, establishes with the nucleic acid bases and the corresponding monophosphate nucleotides. In this investigation, we determine equilibrium geometry of all possible complexes resulting from the attachment of the ion on the different binding sites selected on each ligand. The relative energies of complexes and metal ion affinities are also given. The most meaningful aspect was found to lie in the energetics of this interaction that underlines a very high affinity of aluminum ion for the examined biological systems.