95 research outputs found
Synthesis and cationic polymerization of halogen bonding vinyl ether monomers
Halogen bonding is rapidly becoming recognized as a viable and useful intermolecular interaction in supramolecular chemistry. While various monomers amenable to radical polymerization methods containing halogen bonding donors have been developed, this study aims to expand the type of monomers that incorporate this intermolecular interaction to facilitate use of cationic polymerization by developing three novel vinyl ether monomers containing halogen bonding donor moieties: 2, 3, 5, 6-tetrafluoro-4-iodophenoxyethyl vinyl ether (C2I), 2, 3, 5, 6-tetrafluoro-4-iodophenoxybutyl vinyl ether (C4I), and 2-(2, 3, 5, 6-tetrafluoro-4-iodophenoxyethoxy)ethyl vinyl ether (O3I). Well controlled cationic polymerization is achievable through the use of a proton trap, 2, 6-di-tert-butylpyridine. The use of SnCl4 as a co-Lewis acid was found to accelerate the reaction. Between the three monomers, the difference in the chain length is shown to influence the reaction rate, with the longest chain demonstrating the fastest polymerization. Initial studies of the halogen bonding ability shows that halogen bonding exists for all three monomers but is most pronounced in C4I. The polymerized vinyl ethers also exhibit halogen bonding. Due to the ease of synthesis and polymerization, these are promising new monomers to increase functionality available for polymers synthesized using cationic polymerization
First magmatism in the New England Batholith, Australia: forearc and arc–back-arc components in the Bakers Creek Suite gabbros
The New England Orogen, eastern Australia, was
established as an outboard extension of the Lachlan Orogen through the
migration of magmatism into forearc basin and accretionary prism sediments.
Widespread S-type granitic rocks of the Hillgrove and Bundarra supersuites
represent the first pulse of magmatism, followed by I- and A-types typical
of circum-Pacific extensional accretionary orogens. Associated with the
former are a number of small tholeiite–gabbroic to intermediate bodies of
the Bakers Creek Suite, which sample the heat source for production of
granitic magmas and are potential tectonic markers indicating why magmatism
moved into the forearc and accretionary complexes rather than rifting the
old Lachlan Orogen arc. The Bakers Creek Suite gabbros capture an early
( ∼ 305 Ma) forearc basalt-like component with low Th ∕ Nb and
with high Y ∕ Zr and Ba ∕ La, recording melting in the mantle wedge with little
involvement of a slab flux and indicating forearc rifting. Subsequently,
arc–back-arc like gabbroic magmas (305–304 Ma) were emplaced, followed by
compositionally diverse magmatism leading up to the main S-type granitic
intrusion ( ∼ 290 Ma). This trend in magmatic evolution
implicates forearc and other mantle wedge melts in the heating and melting
of fertile accretion complex sediments and relatively long ( ∼ 10 Myr) timescales for such melting
Initial Decomposition Reactions of Bicyclo-HMX [BCHMX or cis
We investigated the initial chemical reactions of BCHMX [cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole] with the following procedure. First we used density functional theory molecular dynamics simulations (DFT-MD) on the periodic crystal to discover the initial reaction steps. This allowed us to determine the most important reactions through DFT-MD simulations at high temperatures. Then we started with the midpoint of the reaction (unimolecular or bimolecular) from the DFT-MD and carried out higher quality finite cluster DFT calculations to locate the true transition state of the reaction, followed by calculations along the reaction path to determine the initial and final states. We find that for the noncompressed BCHMX the nitro-aci isomerization reaction occurs earlier than the NO2-releasing reaction, while for compressed BCHMX intermolecular hydrogen-transfer and bimolecular NO2-releasing reactions occur earlier than the nitrous acid (HONO)-releasing reaction. At high pressures, the initial reaction involves intermolecular hydrogen transfer rather than intramolecular hydrogen transfer, and the intermolecular hydrogen transfer decreases the reaction barrier for release of NO2 by ∼7 kcal/mol. Thus, the HONO-releasing reaction takes place more easily in compressed BCHMX. We find that this reaction barrier is 10 kcal/mol lower than the unimolecular NO2 release and ∼3 kcal/mol lower than the bimolecular NO2 release. This rationalizes the origin of the higher sensitivity of BCHMX compared to RDX (1,3,5-trinitrohexahydro-1,3,5-triazine) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). We suggest changes in BCHMX that might help decrease the sensitivity by avoiding the intermolecular hydrogen-transfer and HONO-releasing reaction
Effects of cognitive-behavioral programs for criminal offenders
Cognitive-behavioral therapy (CBT) is among the more promising rehabilitative treatments for
criminal offenders. Reviews of the comparative effectiveness of different treatment approaches
have generally ranked it in the top tier with regard to effects on recidivism (e.g., Andrews et al.,
1990; Lipsey & Wilson, 1998). It has a well-developed theoretical basis that explicitly targets
“criminal thinking” as a contributing factor to deviant behavior (Beck, 1999; Walters, 1990;
Yochelson & Samenow, 1976). And, it can be adapted to a range of juvenile and adult
offenders, delivered in institutional or community settings by mental health specialists or
paraprofessionals, and administered as part of a multifaceted program or as a stand-alone
intervention. Meta-analysis has consistently indicated that CBT, on average, has significant
positive effects on recidivism. However, there is also significant variation across studies in the
size of those treatment effects. Identification of the moderator variables that describe the study
characteristics associated with larger and smaller effects can further develop our understanding
of the effectiveness of CBT with offenders. Of particular importance is the role such moderator
analysis can play in ascertaining which variants of CBT are most effective. The objective of this
systematic review is to examine the relationships of selected moderator variables to the effects
of CBT on the recidivism of general offender populations
Patterns of genetic divergence among populations of the pseudometallophyte Biscutella laevigata from southern Poland
Geochemical, isotopic and petrographic constraints on the origin and development of the Barrington Tops Batholith
The Barrington Tops Batholith (BTB) is an Early Permian, granodioritic suite intruding the Tamworth Belt in the Southern New England Fold Belt (SNEFB), as shown in Fig. 1. It is composed of three plutons of two comagmatic compositions: the two larger plutons, Omadale Brook and Barrington River, are augitehypersthene granodiorite, while the Gummi Plain pluton, to the north-east is a hornblende-biotite granodiorite (Mason and Kaverlieris 1984; Eggins and Hensen 1987). In addition to the granodiorites, Eggins (1984) notes the presence of several phases of dyke and stock intrusion. Two phases of mafic dykes are associated with the plutons, one intruding before the plutons, and one after. In addition, aplitic and microgranodioritic dykes of similar mineralogy to the main suite are known. These felsic intrusives are noted on the margins of the intrusions and are seen in both the granodiorites and their surrounding aureole. Finally, Eggins (1984) notes the presence of quartz diorite intrusives in several locations around the BTB. However, poor outcrop means that the relationship between these and the other intrusives has not been discerned
Building the New England Batholith, eastern Australia-linking granite petrogenesis with geodynamic setting using Hf isotopes in zircon
U-Pb and Hf isotope analysis of zircons from granitoids of the Permian-Triassic New England Batholith (eastern Australia) was carried out to provide constraints on the evolution of an isotopically and compositionally diverse batholith. Incipient plutonism in the early Permian resulted in the formation of isotopically evolved, peraluminous granodiorites of the Hillgrove Suite. Following this, mixing between crustal-derived (+. 5-+. 8 ΕHf units) and depleted mantle-derived magmas (+. 13-+. 18 ΕHf units), was responsible for the formation of the c. 282. Ma Bundarra Suite. The strongly metaluminous and isotopically depleted granites of the c. 268. Ma Clarence River Suite (+. 11-+. 16 ΕHf units) signify an increased role of isotopically depleted magmas during the formation of plutonic rocks in the middle Permian. Interestingly, this isotopic and chemical transience coincides with orogenic extension that was associated with the relocation for the southern New England Orogen (NEO) from a continental margin accretionary setting to that of a back-arc basin. Following attenuation, the NEO was thickened by contraction during the Hunter Bowen Event (265-255. Ma).Forming after the Hunter Bowen Event, the metaluminous rocks of the c. 256. Ma Moonbi Suite were the product of mixing between magmas derived from evolved metaigneous rocks and enriched mantle (+. 3-+. 8 ΕHf units). We attribute the switch in isotopic character from highly depleted (i.e., Clarence River Suite) to evolved (i.e., Moonbi Suite) to crustal thickness before (i.e., thin) and after (i.e., thick) the Hunter Bowen Event. Evidence of renewed mixing between depleted and evolved magmas characterises the formation of the c. 249. Ma Uralla Suite (+. 7-+. 16 ΕHf units), which interestingly, was coeval with renewed orogenic extension in the early Triassic. Finally, the melting of deep crustal basalts below the southern New England Orogen in the middle Triassic (c. 233. Ma) resulted in the formation of moderately depleted leucomonzogranites and A-type magmas (+. 9-+. 12 ΕHf units).Through combining new U-Pb and Hf zircon isotope data with pre-existing whole rock Nd and geochemical data, a link between geodynamic setting and granite petrogenesis has been identified, where: (i) in thick orogens, granites formed via partial melting of the crust and lack a significant depleted component; (ii) in thin orogens, granites form by mixing of crustal-derived and depleted mantle-derived magmas; and (iii) in highly attenuated orogens, granites can be extremely depleted and dominantly derived from the melting of upper mantle sources. This relationship may be associated with the development or reactivation of lithosphere scale detachments during orogenic extension that could facilitate the transportation of depleted magmas into the crust.12 page(s
Genesis and age of magmas of the Hillgrove Batholith, southern New England Orogen
Intrusive igneous suites in the southern New England Orogen span in age from the latest Carboniferous to late Triassic (Fig. 1). The Hillgrove Batholith (informal name) constitutes the oldest intrusive batholith within the accretion-subduction complex of the southern New England Orogen. The batholith is defined here as comprising The Hillgrove Supersuite and the Bakers Creek Supersuite (informal name). The Hillgrove Suite was originally defined by Binns et al. (1967) and several member plutons have been added since by Pogson and Hitchins (1973), Shaw and Flood (1981) and Gilligan et al. (1992). The latter definition included 23 plutons including the Blue Knobby, Campfire, Eastlake, Enmore, Gara, Garibaldi, Glenifer, Gostwyck, Henry River, Hillgrove, Ingleba, Kimberley Park, Kookabookra, Murder Dog, Rockvale and Tobermory monzogranites, together with the Abroi, Argyll, Dundurrabin, Rockisle, Tia and Winterbourne granodiorites. The Hillgrove Supersuite as defined here, includes all of these with the tentative addition of the Harnham Grove Porphyritic Microtonalite which has an age (Black, 2007) within error of other members of the supersuite
Late Palaeozoic retreating and advancing subduction boundary in the New England Fold Belt, New South Wales
Compositions of Carboniferous and Lower Permian mafic and felsic magmatic rocks from the southern New England Fold Belt, combined with a time-space evaluation of appropriate regional geological elements, indicate that Late Palaeozoic tectonic events can be simply explained in terms of ongoing west-dipping subduction. The diversity of igneous rock types and tectonostratigraphic assemblages are interpreted to reflect sequential development of a stationary (Carboniferous), retreating (Early Permian) and advancing (Late Permian) subduction boundary along the active continental margin of East Gondwana. The stationary Carboniferous subduction boundary is expressed as a dual magmatic chain comprising a volcanic arc front of intermediate-felsic volcanic rocks in the Tamworth Belt and a subparallel rear-arc chain of granitoids and rare high-K gabbroic rocks represented by the Bathurst Batholith and satellite plutons. Waning of arc-front magmatism at ca 330 Ma corresponded to climactic activity in the rear-arc between 330 Ma and 320 Ma. Subduction boundary retreat is reflected by outboard migration of magmatism into the former accretionary prism of the Tablelands Complex, represented by the ca 300 Ma S-type Hillgrove Suite granites and coeval Bakers Creek Suite gabbros. Trace-element chemistry of these gabbros, and of Lower Permian basalts in the nascent Sydney Basin, suggests generation in a backarc setting. The 290-270 Ma Sydney Basin basalts record a transition from steep to flat, N-MORB normalised chemical trends, which suggests progressive upper plate (Gondwanan) lithospheric thinning during ongoing subduction boundary retreat. The S-type Bundarra and I-type Barrington Tops granite suites formed from contrasting crustal sources in this Early Permian extensional backarc setting. A reversal to compressional deformation is recorded by the Late Permian Hunter-Bowen Orogeny, which placed the Sydney-Bowen Basin in a foreland setting. An increasing volume of volcanic material, coincident with an increase in the proportion and thickness of conglomeratic units in the Late Permian foreland deposits, is considered to represent the westward translation of the orogenic front and magmatic arc back toward the old Carboniferous continental margin, reflecting an advancing subduction boundary. Voluminous post-tectonic, high-K calc-alkaline plutonism in the New England Batholith indicates establishment of the main magmatic arc in the New England Fold Belt, during the latest Permian - Early Triassic. It completes the cycle of subduction boundary retreat and advancement in the Late Palaeozoic
Towards a Temperature-Responsive Pinecone-Inspired Actuator Using Silicone Encapsulated Hydrogels.
- …