Thermal analysis and phase evolution of ferroelectric PbTiO<Subscript>3</Subscript> obtained from silicate and borate based glasses

This article assessed the glass formability for crystallization of lead titanate (PbTiO₃) as the primary phase. It was found that silicate-based glasses formed glass as a block without the need for cold splatting, but B₂O₃-based glasses needed to be prepared by cold splatting to retard devitrification. Also, incorporation of BaO was favoured by an increase in the concentration of B₂O₃. DTA showed the crystallization of crystalline phases occurred above glass transition temperature. XRD traces supported the DTA data where the first exothermic peak in each case was presumed to be related to the crystallization of PbTiO₃ (PT) phase. XRD also showed the lower c/a ratios compared to pure PT ceramic, which suggested three possibilities for lower values: crystal clamping by the rigid glass matrix, intrinsic size effect and incorporation of impurities in the PT phase.     

Welfare or Work? Low-Income Working Households' Housing Consumption in the Private Rented Sector in England

This paper is concerned with issues of equity and efficiency in the Housing Benefit (HB) system in the private rented sector (PRS) in England. Using information from a survey of low- income working households (LIWH) and in-depth interviews with LIWH families, it addresses two policy-relevant questions. First, there are mixed findings on whether the current HB system enables HB recipients to consume more housing than is available to otherwise similar non-HB-recipient households in the PRS. HB rules on eligible property size appear not to unduly favour HB claimants compared with LIWH. LIWH, however, tend to pay a rent which is less than the maximum amount an HB recipient could receive. This is particularly true for LIWH families with children who are most likely to be living in properties smaller than allowed by HB regulations. Second, there is no evidence that the HB system incentivises LIWH to give up work or otherwise seek to become eligible for HB.     

A communication-based intervention for nonverbal children with autism: What changes? Who benefits?

Objective: This article examines the form and function of spontaneous communication and outcome predictors in nonverbal children with autism following classroom-based intervention (Picture Exchange Communication System [PECS] training). Method: 84 children from 15 schools participated in a randomized controlled trial (RCT) of PECS (P. Howlin, R. K. Gordon, G. Pasco, A. Wade, & T. Charman, 2007). They were aged 4–10 years (73 boys). Primary outcome measure was naturalistic observation of communication in the classroom. Multilevel Poisson regression was used to test for intervention effects and outcome predictors. Results: Spontaneous communication using picture cards, speech, or both increased significantly following training (rate ratio [RR] =1.90, 95% CI [1.46, 2.48], p     

The Medieval Tailor’s Assistant

Abstract

These books are not available from the Costume Society but must be obtained from bookshops or the institutions concerned     

UV-/thermal processing of sol-gel-derived lead-magnesium-niobium titanate thin films

This work aimed to describe the sol-gel synthesis and preparation of a near-morphotropic phase boundary lead-magnesium-niobium titanate (PMNT) material system, and to investigate the influences of room-temperature-UV-irradiation and rapid thermal annealing (RTA) processes on the properties of its thin films. It was postulated that the use of UV-irradiation prior to thermal processing could play a role in the generation of a structural difference that would manifest itself via the formation of a higher film thickness, which was more pronounced at higher RTA temperatures The PMNT thin film system described here (particularly those annealed at higher temperatures) appeared to be potentially suitable for ultrahigh-value-capacitor applications; the unexposed film annealed at 750 °C exhibited the highest high k value (1425) with a strongly pronounced perovskite phase (97%).     

Solid state complexes of poly(L‐lysine) with metal chlorides from the 1st row of the d‐block

Solid state characterization of poly(L‐lysine)hydrobromide was obtained via differential scanning calorimetry, thermogravimetric analysis, optical microscopy and infrared spectroscopy. The glass transition temperature of poly(L‐lysine)hydrobromide is 178°C. This thermal transition has not been reported previously. Poly(L‐lysine)'s T_g decreases when complexes are produced with the following divalent transition metal chlorides; cobalt chloride hexahydrate, nickel chloride hexahydrate, copper chloride dihydrate and anhydrous zinc chloride. At 10 mol% salt, nickel, chloride decreases T_g by 45°C, and the general trend is Ni²⁺Co²⁺Zn²⁺Cu²⁺. The depression of poly(L‐lysine)'s T_g correlates well with ligand field stabilization energies for pseudo‐octahedral and pseudo‐tetrahedral dⁿ complexes (n = 7, 8, 10) from the 1^st row of the d‐block. However, d⁹ copper(II) complexes cannot be included in this empirical correlation. Infrared spectroscopic evidence suggests that Co²⁺, Ni²⁺ and Zn²⁺ coordinate to the carbonyl oxygen in the main chain of the polymer. When transition metal ions coordinate to C? O, the network of hydrogen bonded amide groups is disrupted, which lowers the glass transition. The amide I region of the infrared spectrum reveals a hydrogen bonded C? O stretch @ 1655 cm^?1 that is characteristic of poly(α‐amino acid) random coil conformations, and a metal‐ligand coordinated C? O stretch @ 1625 cm^?1 in complexes with divalent cobalt, nickel and zinc. The amide II region of the infrared spectrum near 1550 cm^?1 is also sensitive to the formation of coordination complexes with these d‐block metal chlorides.     

Piloting of anionic polymerization of styrene in tetrahydrofurant

Anionic polymerization of styrene in THF with n‐butyllithium/alpha‐methylstyrene initiator is described as a first step in preparation of a styrenic block copoly‐mer. In order to suppress rapid decay of living alpha‐methylstyrene unimers, which occurred at room temperature, the initiation reaction was carried out at ?20(+5)°C. The kinetic parameters of this decay reaction were determined and used for process optimization. By combining experiments with modelling of styrene propagation reaction all key process parameters were defined for l‐L, 38‐L, and 189‐L reactors. A good match was demonstrated between the model and experimental propagation exotherm for semibatch reaction conditions. Overall, it was demonstrated that technical grade THF and styrene could be used at pilot plant scale to prepare well‐defined polymers up to Mn 22 000 via the “living” polymerization mechanism. The resulting polymers had narrow molecular weight distributions (1.06 < Mw/Mn < 1.30).     

Reliability analysis of transparent conductive tracks embossed in ZnO and Al-ZnO sol–gel materials

In this paper, we present a low-cost rapid replication approach to fabricate ZnO and Al-doped ZnO Transparent Conductive Oxide electrode structures using both hard UV curable polyurethane acrylate and soft thermal curable polydimethylsiloxane moulds. The thin films of the ZnO and Al-ZnO sol–gel precursor solution prepared from zinc acetate monoethanolamine and isopropanol were cast into a polydimethylsiloxane or polyurethane acrylate mould containing the electrode design. For soft mould embossing, the sol–gel coated substrate and polydimethylsiloxane mould were dried under vacuum at 70 °C for 3h. While for hard mould embossing, the system was heated at 150 °C for 30 min with 100 N applying force and then demoulded at 80 °C. The formed electrode patterns can be further densified or annealed giving a stable film that retains the embossed shape. The difference of surface profile obtained by soft and hard moulding is detailed and the hard mould is shown to be more suitable for low aspect ratio conductors. And the reliability study on embossed ZnO and Al-ZnO conductive tracks prepared with hard moulds shows that the embossed structure still retains good quality.     

Dead Zones in LX‐17 and PBX 9502

Pin and X‐ray corner turning data have been taken on ambient LX‐17 and PBX 9052, and the results are listed in tables as an aid to future modeling. The results have been modeled at 4 zones/mm with a reactive flow approach that varies the burn rate as a function of pressure. A single rate format is used to simulate failure and detonation in different pressure regimes. A pressure cut‐off must also be reached to initiate the burn. Corner turning and failure are modeled using an intermediate pressure rate region, and detonation occurs at high pressure. The TATB booster is also modeled using reactive flow, and X‐ray tomography is used to partition the ram‐pressed hemisphere into five different density regions. The model reasonably fits the bare corner turning experiment but predicts a smaller dead zone with steel confinement, in contradiction with experiment. The same model also calculates the confined and unconfined cylinder detonation velocities and predicts the failure of the unconfined cylinder at 3.75 mm radius. The PBX 9502 shows a smaller dead zone than LX‐17. An old experiment that showed a large apparent dead zone in Composition B was repeated with X‐ray transmission and no dead zone was seen. This confirms the idea that a variable burn rate is the key to modeling. The model also produces initiation delays, which are shorter than those found in time‐to‐detonation.