The Role of Particle Surface Functionality and Microstructure Development in Isothermal and Non-Isothermal Crystallization Behavior of Polyamide 6/Cellulose Nanocrystals Nanocomposites

Polyamide 6 (PA6)/cellulose nanocrystal (CNC) and aminopropyl triethoxy silane (APS) - modified CNC nanocomposites were prepared by in situ anionic ring opening polymerization and subsequent melt extrusion. The morphological observation of these hybrid systems revealed that the non-modified nanocrystals developed a network-like fibrillar structure while the APS-modified CNCs were finely dispersed mostly as individual whiskers. The isothermal and non-isothermal crystallization kinetics was extensively studied with emphasis on the effects of CNC surface functionality and the subsequent microstructure development on crystallization behavior of these novel nanocomposite systems. The non-modified CNC particles with corresponding fibrillar microstructure were found significantly hinder the crystallization process and spherultic growth of polyamide 6 chains under both isothermal and non-isothermal conditions. On other hand, the surface modified cellulose nanocrystals with improved sub-micron dispersion enhance crystal nucleation in early stages of crystallization while imposing opposite effect in later stages of crystallization resulting in development of relatively smaller defective spherulitic structures

Primordial non-Gaussianity and Dark Energy constraints from Cluster Surveys

Galaxy cluster surveys will be a powerful probe of dark energy. At the same time, cluster abundance is sensitive to any non-Gaussianity of the primordial density field. It is therefore possible that non-Gaussian initial conditions might be misinterpreted as a sign of dark energy or at least degrade the expected constraints on dark energy parameters. To address this issue, we perform a likelihood analysis of an ideal cluster survey similar in size and depth to the upcoming South Pole Telescope/Dark Energy Survey (SPT-DES). We analyze a model in which the strength of the non-Gaussianity is parameterized by the constant fNL; this model has been used extensively to derive Cosmic Microwave Background (CMB) anisotropy constraints on non-Gaussianity, allowing us to make contact with those works. We find that the constraining power of the cluster survey on dark energy observables is not significantly diminished by non-Gaussianity provided that cluster redshift information is included in the analysis. We also find that even an ideal cluster survey is unlikely to improve significantly current and future CMB constraints on non-Gaussianity. However, when all systematics are under control, it could constitute a valuable cross check to CMB observations.Comment: 10 pages, 4 figures. Corrected a minor discrepancy between our earlier definition of fNL and CMB constraints. References adde

SUSY Simplified Models at 14, 33, and 100 TeV Proton Colliders

Results are presented for a variety of SUSY Simplified Models at the 14 TeV LHC as well as a 33 and 100 TeV proton collider. Our focus is on models whose signals are driven by colored production. We present projections of the upper limit and discovery reach in the gluino-neutralino (for both light and heavy flavor decays), squark-neutralino, and gluino-squark Simplified Model planes. Depending on the model a jets + MET, mono-jet, or same-sign di-lepton search is applied. The impact of pileup is explored. This study utilizes the Snowmass backgrounds and combined detector. Assuming 3000 fb^{-1} of integrated luminosity, a gluino that decays to light flavor quarks can be discovered below 2.3 TeV at the 14 TeV LHC and below 11 TeV at a 100 TeV machine.Comment: 81 pages, 55 figures; v2 journal versio

Quantifying the complexity of random Boolean networks

We study two measures of the complexity of heterogeneous extended systems, taking random Boolean networks as prototypical cases. A measure defined by Shalizi et al. for cellular automata, based on a criterion for optimal statistical prediction [Shalizi et al., Phys. Rev. Lett. 93, 118701 (2004)], does not distinguish between the spatial inhomogeneity of the ordered phase and the dynamical inhomogeneity of the disordered phase. A modification in which complexities of individual nodes are calculated yields vanishing complexity values for networks in the ordered and critical regimes and for highly disordered networks, peaking somewhere in the disordered regime. Individual nodes with high complexity are the ones that pass the most information from the past to the future, a quantity that depends in a nontrivial way on both the Boolean function of a given node and its location within the network.Comment: 8 pages, 4 figure

Rheology of Tin Fluorophosphate Glass/Polyamide 12 Hybrids in the Low Concentration Regime

Phosphate glass (Pglass)/polymer hybrids are a unique material class that promises to help fulfill the growing need for new advanced materials. Rheological investigations into Pglass/polyamide 12 hybrids have shown a strong dependence on temperature and composition. Strong negative deviations from the log-additivity rule are also observed for these materials as well as a reduction in the activation energy for viscous flow. Hybrids containing \u3c 2 vol. % Pglass are theologically simple fluids that display temperature independence in plots of storage modulus versus loss modulus. Hybrids containing \u3e= 2 vol. % Pglass are rheologically complex and do not obey the time-temperature superposition principle. Through application of Han plots, we identified a structural change that occurs in hybrids containing \u3e= 2 vol. % Pglass at temperatures in excess of 220 degrees C. This microstructural change induces an apparent yield stress in the material at these elevated temperatures. It is believed that the microstructural change is due to enhanced interactions that occur at elevated temperatures between the compatible pure components of the hybrids. (c) 2007 The Society of Rheology

Biogas generation from Watermelon peels, Pineapple peels and Food wastes

the anaerobic digestion process for biogas production was investigated using locally available waste materials (watermelon peels, pineapple peels and food wastes). Watermelon peels and pineapple peels each was codigested with food wastes in ratio 1:1 while using rumen contents of cattle as inoculum. The physical, chemical and microbial characteristics of the three substrates were determined before and after the co-digestion process using standard methods. Analysis of the generated gas revealed 68.0% Methane, 20.0% Carbon dioxide, 6.0% Nitrogen, 2.5% Hydrogen, 1.5% Hydrogen sulfide and 2.0% Oxygen for co-digestion of watermelon peels with food wastes while co-digestion of pineapple peels with food wastes yielded 71.0% Methane, 18.0% Carbon dioxide, 7.0% Nitrogen,l.5% Hydrogen, 1.5% Hydrogen sulfide and 1.0% Oxygen. The anaerobic digestion was found to be efficient in terms of pathogen treatment, since the reduction of coliforms reached five logarithmic units. The availability and renewable nature of biomass, green energy production and ease of management and deployment of energy produced makes biogas a better option to fossil fuel and thus could be the much awaited solution to energy crisis in Nigeria and other developing nations

Biocompatibility of Synthetic Poly(Ester urethane)/Polyhedral Oligomeric Silsesquioxane Matrices with Embryonic Stem Cell Proliferation and Differentiation

Incorporation of polyhedral oligomeric silsesquioxanes (POSS) into poly(ester urethanes) (PEU) as a building block results in a PEU/POSS hybrid polymer with increased mechanical strength and thermostability. An attractive feature of the new polymer is that it forms a porous matrix when cast in the form of a thin film, making it potentially useful in tissue engineering. In this study, we present detailed microscopic analysis of the PEU/POSS matrix and demonstrate its biocompatibility with cell culture. The PEU/POSS polymer forms a continuous porous matrix with open pores and interconnected grooves. From SEM image analysis, it is calculated that there are about 950 pores/mm2 of the matrix area with pore diameter size in the range 1-15 μm. The area occupied by the pores represents approximately 7.6% of the matrix area. Using mouse embryonic stem cells (ESCs), we demonstrate that the PEU/POSS matrix provides excellent support for cell proliferation and differentiation. Under the cell culture condition optimized to maintain self-renewal, ESCs grown on a PEU/POSS matrix exhibit undifferentiated morphology, express pluripotency markers and have a similar growth rate to cells grown on gelatin. When induced for differentiation, ESCs underwent dramatic morphological change, characterized by the loss of clonogenecity and increased cell size, with well-expanded cytoskeleton networks. Differentiated cells are able to form a continuous monolayer that is closely embedded in the matrix. The excellent compatibility between the PEU/POSS matrix and ESC proliferation/differentiation demonstrates the potential of using PEU/POSS polymers in future ESC-based tissue engineering. Copyright (C) 2010 John Wiley & Sons, Ltd

Experimental Study on the Use of Waste Polyethylene Terephthalate (PET) and River Sand in Roof Tile Production

This study deals with the effects of using Polyethylene Terephthalate (PET) and river sand in roof tile production. This work is based on experimental study of roof tiles produced with river sand and recycled PET in varying proportion of 10%, 20%, 30%, 40%, 50%, 60% and 100% of PET combined with the corresponding fine aggregate percentage. The PET plastics used were derived from waste plastic bottles for soft drinks. The shredded plastic was subjected to heat and ensured that it does not lose it’s plasticity. The tests which were performed to evaluate the physical and mechanical performance of this material were sieve analysis, specific gravity, water absorption, density and compressive strength. The results show that recycled PET replacement gives better results for 40 and 50% of plastic composite tile than Ordinary Portland Cement (OPC) at 28 days. In conclusion, the plastic composite tiles have both good strength and absorptive property for roof tiling

Corn and soybean yield responses to micronutrients fertilization

Micronutrients such as boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) are essential plant nutrients taken up by crops in very small amounts, but a deficiency can have profound effects on yield because they perform important physiological functions. Deficiencies seldom are observed or are widespread in Iowa and neighboring states. Farmers and crop consultants have been asking questions, however, concerning possible yield loss due to deficiency of micronutrients in corn and soybean

AUDIT COMMITTEE ATTRIBUTES AND AUDIT QUALITY: A BENCHMARK ANALYSIS

This study examined audit committee attributes and audit quality with emphasis on the specific requirements of the 2011 SEC code. The study applied the deductive approach via the expost facto research design and the Binary probit regression model in analyzing the various hypotheses put forward in study. Data used for the study were gathered for 150 firm-year observations from the annual reports of quoted companies on the floor of the Nigerian Stock Exchange. Findings from the study revealed that audit committee size, frequency of meetings, number of expertise and overall effectiveness all have a positive relationship with audit quality. However, only size and overall effectiveness was significant in their relationship. The study recommends that since the significant positive nature of audit committee effectiveness show that four attributes jointly account for effectiveness, firms are encouraged to establish audit committees that have all these attributes. Furthermore, the requirement of having a 6-member audit committee is sound and empirically proven to aid audit quality. Therefore, firms yet to subscribe to these should hasten up, while sanctions should be made for firms that do not