Electrical and dielectric properties of uncoated and coated wood-free paper for electrophotography

The print substrate influences the print result in dry toner electrophotography, which is a widely used digital printing method. The influence of the substrate can be seen more easily in color printing, as that is a more complex process compared to monochrome printing. However, the print quality is also affected by the print substrate in grayscale printing. It is thus in the interests of both substrate producers and printing equipment manufacturers to understand the substrate properties that influence the quality of printed images in more detail. In dry toner electrophotography, the image is printed by transferring charged toner particles to the print substrate in the toner transfer nip, utilizing an electric field, in addition to the forces linked to the contact between toner particles and substrate in the nip. The toner transfer and the resulting image quality are thus influenced by the surface texture and the electrical and dielectric properties of the print substrate. In the investigation of the electrical and dielectric properties of the papers and the effects of substrate roughness, in addition to commercial papers, controlled sample sets were made on pilot paper machines and coating machines to exclude uncontrolled variables from the experiments. The electrical and dielectric properties of the papers investigated were electrical resistivity and conductivity, charge acceptance, charge decay, and the dielectric permittivity and losses at different frequencies, including the effect of temperature. The objective was to gain an understanding of how the electrical and dielectric properties are affected by normal variables in papermaking, including basis weight, material density, filler content, ion and moisture contents, and coating. In addition, the dependency of substrate resistivity on the electric field applied was investigated. Local discharging did not inhibit transfer with the paper roughness levels that are normal in electrophotographic color printing. The potential decay of paper revealed that the charge decay cannot be accurately described with a single exponential function, since in charge decay there are overlapping mechanisms of conduction and depolarization of paper. The resistivity of the paper depends on the NaCl content and exponentially on moisture content although it is also strongly dependent on the electric field applied. This dependency is influenced by the thickness, density, and filler contents of the paper. Furthermore, the Poole-Frenkel model can be applied to the resistivity of uncoated paper. The real part of the dielectric constant ε’ increases with NaCl content and relative humidity, but when these materials cannot polarize freely, the increase cannot be explained by summing the effects of their dielectric constants. Dependencies between the dielectric constant and dielectric loss factor and NaCl content, temperature, and frequency show that in the presence of a sufficient amount of moisture and NaCl, new structures with a relaxation time of the order of 10-3 s are formed in paper. The ε’ of coated papers is influenced by the addition of pigments and other coating additives with polarizable groups and due to the increase in density. The charging potential decreases and the electrical conductivity, potential decay rate, and dielectric constant of paper increase with increasing temperature. The dependencies are exponential and the temperature dependencies and their activation energies are altered by the ion content. The results have been utilized in manufacturing substrates for electrophotographic color printing.

Variation in susceptibility among macadamia genotypes and species to Phytophthora root decay caused by Phytophthora cinnamomi

Phytophthora cinnamomi is a major pathogen of cultivated macadamia (Macadamia integrifolia, Macadamia tetraphylla and their hybrids) worldwide. The susceptibility of the two non-edible Macadamia species (Macadamia ternifolia and Macadamia jansenii) to P. cinnamomi is not well-understood. Commercial macadamia trees are established on grafted seedling (seed propagation) or own-rooted cutting (vegetative propagation) rootstocks of hybrids of the cultivated species. There is little information to support the preferential use of rootstock propagated by either seedling or own-rooted cutting methods in macadamia. In this study we assessed roots of macadamia plants of the four species and their hybrids, derived from the two methods of propagation, for their susceptibility to P. cinnamomi infection. The roots of inoculated plant from which P. cinnamomi was recovered showed blackening symptoms. The non-cultivated species, M. ternifolia and M. jansenii and their hybrids were the most susceptible germplasm compared with M. tetraphylla and M. integrifolia. Of these two species, M. tetraphylla was less susceptible than M. integrifolia. Significant differences were observed among the accessions of their hybrids. A strong association (R2 > 0.75) was recorded between symptomatic roots and disease severity. Root density reduced with increasing disease severity rating in both own-rooted cuttings (R2 = 0.65) and germinated seedlings (R2 = 0.55). P. cinnamomi severity data were not significantly (P > 0.05) different between the two methods of plant propagation. The significance of this study to macadamia breeding and selection of disease resistant rootstocks is discussed.

Inflaton dark matter from incomplete decay

We show that the decay of the inflaton field may be incomplete, while nevertheless successfully reheating the Universe and leaving a stable remnant that accounts for the present dark matter abundance. We note, in particular, that since the mass of the inflaton decay products is field dependent, one can construct models, endowed with an appropriate discrete symmetry, where inflaton decay is kinematically forbidden at late times and only occurs during the initial stages of field oscillations after inflation. We show that this is sufficient to ensure the transition to a radiation-dominated era and that inflaton particles typically thermalize in the process. They eventually decouple and freeze out, yielding a thermal dark matter relic. We discuss possible implementations of this generic mechanism within consistent cosmological and particle physics scenarios, for both single-field and hybrid inflation.

Differences in grain growth of calcite: a field-based modeling approach

Normal grain growth of calcite was investigated by combining grain size analysis of calcite across the contact aureole of the Adamello pluton, and grain growth modeling based on a thermal model of the surroundings of the pluton. In an unbiased model system, i.e., location dependent variations in temperature-time path, 2/3 and 1/3 of grain growth occurs during pro- and retrograde metamorphism at all locations, respectively. In contrast to this idealized situation, in the field example three groups can be distinguished, which are characterized by variations in their grain size versus temperature relationships: Group I occurs at low temperatures and the grain size remains constant because nano-scale second phase particles of organic origin inhibit grain growth in the calcite aggregates under these conditions. In the presence of an aqueous fluid, these second phases decay at a temperature of about 350 °C enabling the onset of grain growth in calcite. In the following growth period, fluid-enhanced group II and slower group III growth occurs. For group II a continuous and intense grain size increase with T is typical while the grain growth decreases with T for group III. None of the observed trends correlate with experimentally based grain growth kinetics, probably due to differences between nature and experiment which have not yet been investigated (e.g., porosity, second phases). Therefore, grain growth modeling was used to iteratively improve the correlation between measured and modeled grain sizes by optimizing activation energy (Q), pre-exponential factor (k0) and grain size exponent (n). For n=2, Q of 350 kJ/mol, k0 of 1.7×1021 μmns−1 and Q of 35 kJ/mol, k0 of 2.5×10-5 μmns−1 were obtained for group II and III, respectively. With respect to future work, field-data based grain growth modeling might be a promising tool for investigating the influences of secondary effects like porosity and second phases on grain growth in nature, and to unravel differences between nature and experiment.

Rural Decay Almanac

Rural Decay Almanac is an exhibition comprised of sculptural objects and video/sound documentation. The following is an explanation of inspiration and personal history, a proposed schematic/manual for the objects in the gallery, and other contemporary artists I frame myself within. The front half of The Art Gallery at the University of Maryland as well as the atrium space directly outside the gallery hosts the work: four large scale Site-Responsive sculptural objects, and one video/sound loop projection. The library of materials comes from a farm site in Ijamsville, MD which has been re-purposed into the structures. As a sister work, the process of dismantling documentation is shown alongside the objects in a sound/video installation. The gallery space is transformed into a meticulously controlled environment via hard objects, sound, light, and video.

Novel criteria for exponential stability of linear neutral time-varying differential systems

Using a novel approach, we get explicit criteria for exponential stability of linear neutral time-varying differential systems. A brief discussion to the obtained results is given. To the best of our knowledge, the results of this paper are new.

On the existence and exponential attractivity of a unique positive almost periodic solution to an impulsive hematopoiesis model with delays

Abstract In this paper, a generalized model of hematopoiesis with delays and impulses isconsidered. By employing the contraction mapping principle and a novel type of impulsivedelay inequality, we prove the existence of a unique positive almost periodic solution of themodel. It is also proved that, under the proposed conditions in this paper, the unique positivealmost periodic solution is globally exponentially attractive. A numerical example is givento illustrate the effectiveness of the obtained results.

Audit of gross decay treatment in young children under general anaesthetic

Abstract In Australia, dental caries is one of the most prevalent diseases effecting children. For more severe cases a dental general anaesthetic (GA) is required. A retrospective analysis of clinical records for all patients aged up to 10 years who attended Barwon Health (Geelong, Victoria, Australia) for a dental GA from 2010-2012 was performed. There were 236 separate events in 234 children, with 223 new cases and 11 that had already received a dental GA prior to the study period. The average age of patients at their dental GA procedure was 6.3 ± 2.0 years. Prior to the GA, the average dmft/ DMFT was 8 (6-12) (median, interquartile range). The length of time from referral to GA increased significantly from 166.4 days (SD 108.1), 164.3 days (SD 98.9) to225.4 days (SD 129.5) in 2010, 2011 and 2012, respectively. Follow up review appointments after GA appointment was attended by 10.8%, 37.3% and 36.0% of patients, respectively across the same years. Following the findings of long waiting times for GA procedures for children with severe dental caries, and the low rate of attendance for post-GA reviews, a change in dental process is urgently needed.

Exponential stability of time-delay systems via new weighted integral inequalities

In this paper, new weighted integral inequalities (WIIs) are first derived based on Jensen's integral inequalities in single and double forms. It is theoretically shown that the newly derived inequalities in this paper encompass both the Jensen inequality and its most recent improvement based on Wirtinger's integral inequality. The potential capability of WIIs is demonstrated through applications to exponential stability analysis of some classes of time-delay systems in the framework of linear matrix inequalities (LMIs). The effectiveness and least conservativeness of the derived stability conditions using WIIs are shown by various numerical examples.

Inhibition of nonsense-mediated mRNA decay by the cytoplasmic poly(A)-binding protein

The expression of a gene from transcription of the DNA into pre-messenger RNA (pre-mRNA) over translation of messenger RNA (mRNA) into protein is constantly monitored for errors. This quality control is necessary to guarantee successful gene expression. One quality control mechanism important to this thesis is called nonsense-mediated mRNA decay (NMD). NMD is a cellular process that eliminates mRNA transcripts harboring premature translation termination codons (PTCs). Furthermore, NMD is known to regulate certain transcripts with long 3′ UTRs. However, some mRNA transcripts are known to evade NMD. The mechanism of NMD activation has been subjected to many studies whereas NMD evasion or suppression still remains rather elusive. It has previously been shown that the cytoplasmic poly(A)-binding protein (PABPC1) is able to suppress NMD of certain transcripts. In this study I show that PABPC1 is able to suppress NMD of a long 3′ UTR-carrying reporter when tethered immediately downstream of the termination codon. I further am able to show the importance of the interaction between PABPC1 and eIF4G for NMD suppression, whereas the interaction between PABPC1 and eRF3a seems dispensable. These results indicate an involvement of efficient translation termination and potentially ribosome recycling in NMD suppression. I am able to show that if PABPC1 is too far removed from the terminating ribosome NMD is activated. After showing the importance of PABPC1 recruitment directly downstream of a terminating ribosome in NMD suppression, I am further able to demonstrate several different methods by which PABPC1 can be recruited. Fold-back of the poly(A)-tail mediated by two interacting proteins on opposite ends of a 3′ UTR manages to bring PABPC1 bound to the poly(A)-tail into close proximity of the terminating ribosome and therefore suppress NMD. Furthermore, small PAM2 peptides that are known to interact with the MLLE domain of PABPC1 are able to strongly suppress NMD initiated by either a long 3′ UTR or an EJC. I am also able to show the NMD antagonizing power of recruited PABPC1 for the known endogenous NMD target β-globin PTC39, which is responsible for the disease β-thalassemia. This shows the potential medical implications and application of suppressing NMD by recruiting PABPC1 into close proximity of a terminating ribosome.

Trace memory: after decay

In this exhibition, interdisciplinary artist Tonya A. Meyrick presents a body of new work that explores the relationship between memory and place.Tonya A. Meyrick explores the recollection and perception of memory and considers how our memories are not stable; rather, they are fickle and tied to the places which we inhabit, past events and the ebb and flow of our daily patterns. The act of remembering, putting our memories back together is the thread that runs through this exhibition of large format digital still and moving artworks coupled with an experience of augmented reality

Exponential stability of non-autonomous neural networks with heterogeneous time-varying delays and destabilizing impulses

In this paper, the problem of global exponential stability analysis of a class of non-autonomous neural networks with heterogeneous delays and time-varying impulses is considered. Based on the comparison principle, explicit conditions are derived in terms of testable matrix inequalities ensuring that the system is globally exponentially stableunder destabilizing impulsive effects. Numerical examples are given to demonstrate the effectiveness of the obtained results.