DuPont (Canada)

This paper demonstrates a low-loss photo patternable polymer waveguide material platform based on benzocyclobutene (BCB) that works in both liquid resins and dry film formats. By precise control of molecule design and refractive index between the core and clad layers, we minimized material absorption at target wavelengths, achieving a propagation loss value of <0.1 dB/cm at 850 nm and <0.3 dB/cm at 1310 nm at the system level based on cutback measurements. We patterned these waveguides on silicon and PCB substrates with laser direct imaging (LDI) or mask aligner, with sub-10 μm accuracy. Moreover, our patterned waveguides maintain thermal stability, with <±5% change in optical loss after multiple reflow processes and 1000 h at 85 °C and 85% humidity (HAST) tests. Lastly, we introduce our modeling framework, predicting transmission, mode profile, and optimal performance of waveguides while considering varying geometries, coupling designs, bend radii, and pitch sizes.

Abstract The increased usage of whole-genome selection (WGS) and other molecular evaluation methods in plant breeding relies on the ability to genotype a very large number of untested individuals in each breeding cycle. Many plant breeding programs evaluate large biparental populations of homozygous individuals derived from homozygous parent inbred lines. This structure lends itself to parent-progeny imputation, which transfers the genotype scores of the parents to progeny individuals that are genotyped for a much smaller number of loci. Here we introduce a parent-progeny imputation method that infers individual genotypes from index-free pooled samples of DNA of multiple individuals using a Hidden Markov Model (HMM). We demonstrated the method for pools of simulated maize double haploids (DH) from biparental populations, genotyped using a genotyping by sequencing (GBS) approach for 3,000 loci at 0.125xto 4xcoverage. We observed high concordance between true and imputed marker scores and the HMM produced well-calibrated genotype probabilities that correctly reflected the uncertainty of the imputed scores. Genomic estimated breeding values (GEBV) calculated from the imputed scores closely matched GEBV calculated from the true marker scores. The within-population correlation between these sets of GEBV approached 0.95 at 1xand 4xcoverage when pooling two or four individuals, respectively. Our approach can reduce the genotyping cost per individual by a factor up to the number of pooled individuals in GBS applications without the need for extra sequencing coverage, thereby enabling cost-effective large scale genotyping for applications such as WGS in plant breeding.

Postfunctionalizable hyperbranched polyurea coatings were prepared by the bulk polycondensation of AB2 monomers on preactivated silicon substrates. As previously shown, AB2 monomers were prepared, comprising a secondary amino group (A) and two blocked isocyanates (B) connected by hexyl spacers, in a single step and in quantitative yields. Covalent anchoring of the coatings on substrates was accomplished by reacting the secondary amino group in the focal point of the polymers with the blocked isocyanates (BIs) of the covalently attached coupling agent. The BIs in the top layer of the coatings were storage-stable under ambient conditions but well-modifiable with amino- or hydroxyl-functional compounds on heating. Attachment of polyethylene glycol or perfluoro-1-decanol afforded hydrophilic or hydrophobic surfaces. Immobilization and quaternization of polyethylenimines yielded highly charged surfaces. The coatings were extensively characterized by a number of techniques, such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and contact -angle measurements.

Abstract Effect of temperature on the hydrodynamics of bubbling gas–solid fluidized beds was investigated in this work. Experiments were carried out at different temperatures ranged of 25–600°C and different superficial gas velocities in the range of 0.17–0.78 m/s with sand particles. The time‐position trajectory of particles was obtained by the radioactive particle tracking technique at elevated temperature. These data were used for determination of some hydrodynamic parameters (mean velocity of upward and downward‐moving particles, jump frequency, cycle frequency, and axial/radial diffusivities) which are representative to solids mixing through the bed. It was shown that solids mixing and diffusivity of particles increases by increasing temperature up to around 300°C. However, these parameters decrease by further increasing the temperature to higher than 300°C. This could be attributed to the properties of bubble and emulsion phases. Results of this study indicated that the bubbles grow up to a maximum diameter by increasing the temperature up to 300°C, after which the bubbles become smaller. The results showed that due to the wall effect, there is no significant change in the mean velocity of downward‐moving clusters. In order to explain these trends, surface tension of emulsion between the rising bubble and the emulsion phase was introduced and evaluated in the bubbling fluidized bed. The results showed that surface tension between bubble and emulsion is increased by increasing temperature up to 300°C, however, after that it acts in oppositely.

Locating existing septic systems and determining the extent of soil contamination after septic system failure can be destructive, time consuming, and a nuisance to homeowners. The objective of this study was to determine the effectiveness of noninvasive electromagnetic induction (EMI) for locating a failed septic system in fine‐textured glacial‐till‐derived soils. Components of a failed septic system were located with a push probe, georeferenced with a theodolite, and surveyed with a dual receiver EMI sensor (DUALEM‐2) in December 2001 (wet soil moisture condition) and July 2002 (dry soil moisture condition). Three transects located perpendicular to the soil absorption field trenches were sampled to a depth of 1.2 m and used to ground reference the EMI survey. Near‐surface (1‐m depth) apparent conductivity (EC a ) was significantly correlated to unweighted average electrical conductivity from soil saturated paste extracts (EC sat ; r = 0.79). The EC a below the soil absorption field was higher than the surrounding native soil under both dry and wet soil moisture conditions. Individual soil absorption trenches had a higher EC a than background EC a under both soil moisture conditions. A higher EC a pattern that was apparent in December 2001 associated with discharge of wastewater at shallow depths was not evident in July 2002 after the system had been abandoned for 6 mo. While more research is warranted, results from this study suggest that electromagnetic induction is a promising technique to identify the location of septic system components, failed septic systems, and their associated effluent plumes.

Chamber and symphony orchestras are considered from four scales of generalization. The macro scale outlines the origins and dispersals of the institution, from ancient times to the present. The meso scale identifies locations for performance, principally halls and their space needs, but also outdoor locations. The mini scale identifies contrasting orchestral spatial organizations, interactions among the musicians, between players and conductor, and issues of gender and race. The micro scale explores the individual musician’s use of space, which becomes a personal place. The interplay between these scales is complex.

Abstract The solubility of water in molten aliphatic polyamides (nylons) of high degrees of polymerization at conditions of subatmospheric water partial pressure and high temperature (225 to 300°C) has been modeled. A simple, semi‐empirical model based on Flory‐Huggins theory was fit to the available literature data for nylons 6, 66, 610 and 11 and to new experimental data for nylon 612. The model contains only two fitted parameters, and is able to adequately describe the available data for the effects of temperature and nylon type on the water concentration in the melt at various water partial pressures.

Abstract A general overview of polyamide technology is presented, with emphasis on commercial practice and technology developed since 1980. The article includes coverage of nomenclature; history; economic, health, and environmental aspects; and physical properties, including crystallinity, solubility, and piezoelectric effects. There is an extensive discussion of chemical properties including methods of preparation (direct amidation, reaction of acid chlorides, and ring‐opening polymerization of lactams via hydrolytic, anionic, and cationic processes); chemical reactions (acidolysis, aminolysis, alcoholysis, ammonolysis, transamidation, transesteramidation, and grafting); and degradation reactions (hydrolysis, thermal degradation, thermooxidation, photodegradation and photooxidation, biodegradation, and mechanodegradation). The manufacturing practices for most commercial nylons that are presented include monomer production for nylon‐6,6, nylon‐6, nylon‐4,6, nylon‐6,9, nylon‐6,10, nylon‐6,12, nylon‐11, nylon‐12, nylon‐12,12, and nylon‐13,13. Nylon‐6,6 and nylon‐6 are compared in detail. There are also discussions of copolyamides, mixed aliphatic–aromatic, and wholly aromatic polyamides. Extensive tables are presented which list CAS Registry Numbers, physical properties, and world‐wide manufacturers of most polyamides.