KEY POINTS This article presents a Bayesian inferential method where the likelihood for a model is unknown, i.e., an implicit likelihood, but where data can easily be simulated from the data model. We use simulated data to estimate the implicit likelihood in a Bayesian analysis employing a Markov chain Monte Carlo algorithm. Two examples are presented.

This article presents a Bayesian inferential method where the likelihood for a model is unknown but where data can easily be simulated from the model. We discretize simulated (continuous) data to estimate the implicit likelihood in a Bayesian analysis employing a Markov chain Monte Carlo algorithm. Three examples are presented as well as a small study on some of the method's properties.

Small-area regrown emitter-base junction InP/InGaAs/InP double heterojunction bipolar transistors (DHBT) using an abrupt InP emitter are presented for the first time. In a device with emitter-base junction area of 0.7 x 8 mum(2), a maximum 183 GHz f(tau) and 165 GHz f(max) are exhibited. To our knowledge, this is the highest reported bandwidth for a III-V bipolar transistor utilizing emitter regrowth. The emitter current density is 6 x 10(5) A /cm(2) at V-CE,V-sat = 1.5 V. The small-signal current gain h(21) = 17, while collector breakdown voltage is near 6 V for the 1560-Angstrom-thick collector. The emitter structure, created by nonselective molecular beam epitaxy regrowth, combines a small-area emitter-base junction and a larger-area extrinsic emitter contact, and is similar in structure to that of a SiGe HBT. The higher f(tau) and f(max) compared to previously reported devices are achieved by simplified regrowth using an InP emitter and by improvements to the regrowth surface preparation process.

We report a 0.7 x 8 mum(2) InAlAs-InGaAs-InP double heterojunction bipolar transistor, fabricated in a molecular-beam epitaxy (MBE) regrown-emitter technology, exhibiting 160 GHz f(T) and 140 GHz f(MAX). These initial results are the first known RF results for a nonselective regrown-emitter heterojunction bipolar transistor, and the fastest ever reported using a regrown base-emitter heterojunction. The maximum current density is J(E) = 8 X 10(5) A/cm(2) and the collector breakdown voltage V-CEO is 6 V for a 1500-Angstrom collector. In this technology, the dimension of base-emitter junction has been scaled to an area as low as 0.3 x 4 mum(2) while a larger-area extrinsic emitter maintains lower emitter access resistance. Furthermore, the application of a refractory metal (Ti-W) base contact beneath the extrinsic emitter regrowth achieves a fully self-aligned device topology.

The combination of chemical composition and microstructure of cast alloy has been found to be critical to the performance of NdFeB sintered magnets. Maximizing the amount of Nd2Fe14B phase (or minimizing the amount of secondary phase) by reducing the Nd content more closely to the stoichiometric composition appears to be essential for obtaining high BHmax magnets. However, α-Fe precipitation has been found to increase with decreasing Nd content and severely hinders the development of high BHmax magnets. A two-step method, incorporating ingot casting and isothermal annealing, has been developed to minimize the amount of precipitated α-Fe in low Nd content alloys. This method provides a drastic improvement in the Br and BHmax of sintered magnets obtained. By decreasing the Nd content to 13 at. % in the cast alloy, incorporating better particle control during fine milling, and controlling grain growth during sintering; magnets with a Br of more than 14.5 kG and a BHmax of 50 MGOe have been consistently obtained. Furthermore, because of the reduction in the amount of Nd-rich grain boundary phase, a significant improvement in the corrosion resistance of magnets was also observed.

Magnets with a nominal composition of Nd14.5Fe79.5B6 have been prepared by the conventional powder metallurgy technique. Precursor alloy powders with average particle sizes of 2.5, 3.0, 3.5, and 4.2 μm were included in this study. Average particle size and oxygen content were effectively manipulated to control the average grain size in the sintered magnets. Typically, for NdFeB sintered magnets, the corrosion resistance of these magnets was improved with increasing oxygen content. The corrosion resistance of magnets varied significantly with the average particle size of precursor alloy powders. For a fixed oxygen content, magnets made from powders of larger sizes exhibited a higher weight loss (a poor corrosion resistance) when compared to those made from smaller alloy powders. However, the Hci of magnets made from 2.5, 3.0, and 3.5 μm precursor alloy powders was found to decrease drastically with increasing oxygen content while magnets made from the 4.2 μm powder was found to remain relatively constant with increasing oxygen content. To optimize magnetic performance, one needs to compromise the corrosion resistance and the Hci obtained by balancing the average particle size of the precursor alloy powder for magnet fabrication, as well as the oxygen content and the average grain size in the finished magnet.

The microstructure of conventionally cast Sm(CobalFe0.28CuvZr0.022)8.0 alloys, where v=0.043–0.092, were examined by optical microscopy and scanning electron microscope with energy dispersed analytical x ray in the as-cast state. In addition to the regular 2:17 matrix phase, the Sm-rich grain boundary phase and the needle-like Zr-rich phases are present in most commercial Sm(Co,Fe,Cu,Zr)z alloys. A grayish Sm- and Cu-rich grain boundary phase was found in alloys with v≥0.07. Attention was focused on the impact of increasing Cu content to the microstructure and process parameters required to produce coercive powder for bonded magnets. An increase of the Cu content from the v value from 0.043 to 0.092 shifts the liquid+2:17→TbCu7-type transformation temperature from slightly above 1180 to approximately 1140 °C. The Hci of optimally prepared magnet was found to increase significantly while the Br remained relative constant when the Cu content is increased. When the Cu content was increased to beyond v=0.07, a slight decrease in the BHmax was noticed. A magnetizing field of 15 kOe and more than 50 kOe were determined to be necessary to charge magnets with a Hci of 12 and 25 kOe, respectively, to about 90% of their full potential. For a composition of Sm(CobalFeuCu0.07Zr0.022)8.0, a slight increase in Fe concentration from u=0.22 to 0.28 was found to increase the Br of an optimally prepared magnet from 8.07 to 8.28 kG and decrease the Hci from 11.8 to 9.7 kOe. A BHmax of 15 MGOe was obtained on a bonded magnet with a composition of Sm(CobalFe0.28Cu0.07Zr0.022)8.0 when the data are normalized to a specific density of 7.0 g/cm3.

Microstructure of ingots with nominal composition of Sm(Co0.68Cu0.065FexZry)(z), where x=0.25, 0.27 and 0.30, y = 0.01, 0.02 and 0.03 and z varies from 7.9 to 8.3, were examined at various homogenizing temperatures and magnetic hardening treatments. It was found that the resulting H-ci is strongly dependent upon the alloy composition and the homogenizing temperature. In general, the H-ci increases as the homogenizing temperature is raised, peaks at a critical temperature, then decreases with increasing homogenizing temperature. This critical temperature may coincide with the solidus curve of the liquid + 2:17 --> TbCu7 type disordered structure transformation. In general, the single phased microstructure achieved after the homogenizing treatment is necessary to obtain the highest H-ci after magnetic hardening. For a fixed thermal treatment, the H-ci was found to increase with the Zr content.

This paper discusses a number of design modifications and changes in operational conditions that have a major influence on the overall performance of the large Coventry municipal incinerator plant (65 MW), which incorporates a heat recovery system for district heating. Four different secondary air-injection systems and various primary air-distribution patterns along the grate were investigated using a computational fluid dynamic model, in an attempt to obtain optimum combustion conditions that would minimize potential emissions of toxic pollutants and reduce maintenance costs at the plant. The modeling work showed that the use of four large high-speed secondary air jets firing toward a common center, together with optimizing the primary air distribution along the grate, produces substantially longer residence times and improves temperature profile at the exit. The novel feature of the proposed secondary air-injection system is the formation of a large and significantly strong recirculation zone, located above the burning refuse bed, in the middle of the furnace shaft. This strong recirculation zone improves the overall performance of the incinerator due to intensive mixing of hot gaseous products evolving from the refuse bed with the combustion air supplied as the secondary air, and greatly improves the gas phase combustion and helps to reduce emissions of chlorinated organic compounds. Results obtained clearly demonstrate that the proposed secondary air-injection system has an excellent potential to satisfy most requirements for emissions levels and gas resident times specified by the European Directives (EEC) for municipal incinerators with a vertical radiation shaft.

Temperature-dependent magnetic properties of nine NdFeB sintered magnets with various Co-Nb, Co-V, or Co-Mo additions have been measured up to 175 °C using both closed-loop and open-circuit methods. The irreversible loss of induction, reversible temperature coefficient of induction (α), and temperature coefficient of intrinsic coercivity β have been related to the Tc, the Br, and the Hci at 25 and 175 °C. The irreversible loss of induction is strongly affected by the Hci at 25 °C and the α has been found to be strongly dependent upon the Tc. Intrinsic coercivity of more than 25 and 7.5 kOe at 25 and 175 °C, respectively, are essential to bring the β to better than −0.5%/ °C. A magnet with a composition of Nd12Dy3Fe70Co5Nb2B8 has been found to exhibit an outstanding thermal stability: a Br of 8.5 kG (comparable to that of SmCo5 sintered magnet) and a Hci of 12.9 kOe when measured at 175 °C. An α of −0.10%/ °C and a β of −0.4%/ °C have been obtained.

The value of knowing the gas residence times in large municipal incinerators and the serious error imposed by the traditional use of gas volume flow rate based average residence time with regard to these incinerators are recognized. There is increasing public awareness and concern over emissions from municipal solid waste incinerators. Modelling studies of particle trajectories using computational fluid dynamics shows the utility of simulation for the determination of residence time distribution in incinerators. These studies indicate that residence time distributions contain valuable information, important to the understanding and evaluation of mixing processes in the incinerator overfire region. A number of design modifications and changes in operational conditions (which have a major influence on the mean gas residence times and overall performance of two large municipal incinerator plants (35 MW and 65 MW) are proposed. Specifically, the effect of high speed jets and different internal baffle configurations have been investigated using mathematical modelling, in an attempt to obtain optimum combustion conditions. This would increase the mean gas residence times, minimize the emission of pollutants and improve the temperature profile throughout the system. The utility of having detailed RTD information for the incinerator overfire region is demonstrated by estimating the residence times using numerical simulation of tracer injection into the 3-dimensional reacting flow field of two typical municipal incinerator configurations. The modelling results not only underscore the critical role played by jets in achieving desirable states of mixing in the overfire region but also point to the significance of the geometry effects.This modelling work has yielded important results, all of which clearly could not be experimentally verified at the industrial scale due to practical and cost limitations. Nevertheless, the results guide specific modifications to the design and operation and this new approach will be of considerable use to the incinerator design community.

We have previously used surface iodination to discriminate between the protein patterns of epithelial cell surfaces in uteri of rabbits receptive (Day 6.5) or nonreceptive (Day 4) to nidation (Ricketts et al. 1984). In this paper, we describe application of the same technique to the trophoblastic surface of rabbit blastocysts collected on the same days of pregnancy. Analysis of labelled proteins by polyacrylamide-gel electrophoresis under denaturing conditions did not reveal qualitative differences between the two days of pregnancy. Scanning densitometry was used to quantitate the area under each protein peak on an autoradiogram; these areas were used as variables in statistical analysis of the protein pattern of individual animals. Quantitative differences between the protein patterns of the two surfaces were detected by canonical variate analysis of the pattern of relative areas of labelled protein peaks. In proteins separated on 7.5% gels, this statistical analysis correctly assigned blastocysts from 8 out of 10 animals to one of two groups according to day of pregnancy. The discrimination was not statistically significant, however, in protein patterns on 12.5% gels, used to give better separation in the lower range of molecular weights. The same analysis in the uterus unequivocally separated the surface iodination patterns from these same days of pregnancy. Thus the changes detected by surface iodination appear to be less pronounced on the trophectoderm than on the uterine epithelium in relation to the time of ovoimplantation.

The ideal gas state thermodynamic properties of 4-methylpyridine have been calculated based on free internal rotation of the methyl group. Selected values are compared with accurate experimental results. (AIP)

Reliable thermodynamic properties of 1,4-dimethylbenzene in the ideal gas state have been recalculated. Selected values are compared with accurate experimental results. Free or very nearly free internal rotation of the methyl groups is deduced. (AIP)

AbstractEs werden zwei neue Dampfdruck‐ Gleichungen angegeben, eine für den gesamten Flüssigkeitsbereich, die andere für einen begrenzten Temp‐Bereich.

Journal Article Community Re-development and Community Re-action Get access D. W. SCOTT D. W. SCOTT Lecturer in Social Administration at the University of Manchester Search for other works by this author on: Oxford Academic Google Scholar Community Development Journal, Volume 13, Issue 3, October 1978, Pages 147–156, https://doi.org/10.1093/cdj/13.3.147 Published: 01 October 1978