Development of Decibel Stepped Attenuator for Automated Sound Level Meter Calibration

MAPAN - Parameter testing in the sound level meter calibration, such as frequency weighting and linearity, needs precise adjustment of sound level in the decibel (dB) unit. In the...     

Quantification of denitrification potential in carbonaceous trickling filters

Biofilm samples from a carbonaceous trickling filter (TF) were evaluated in bench scale reactors to determine their maximum potential denitrification rates. Intact, undisturbed biofilms were placed into 0.6 L bench-scale reactors filled with sterilized, primary clarifier effluent spiked with nitrate to a final concentration of 16-18 mg/L as N. Dissolved oxygen concentrations were maintained between 2 and 4 mg/L in the bulk aqueous phase. Nitrate loss from the reactors was monitored over a 5h period. Denitrification rates of 3.09-5.55 g-N/m(2)day were observed with no initial lag period. This suggests that the capacity for denitrification is inherent in the biofilm and that denitrification can take place even when oxygen is present in the bulk aqueous phase. There were no significant differences in denitrification rates per unit area of media (g-N/m(2)day) either between (a). experimental runs or (b). sampling locations over the trickling filter. This suggests that denitrification potentials are uniform over the entire volume of the full-scale TF. For wastewater treatment plants with TFs that currently nitrify downstream, this approach may be used to meet less stringent permitted discharge concentrations and may allow some facilities to postpone or eliminate construction of additional unit processes for denitrification.     

Multicriteria optimization as enabler for Sustainable Ceramic Matrix Composites

Over the past 40 years, development of Ceramic Matrix Composites (CMCs) has focused mainly on the improvement of material performance and optimization of cost-efficient production routes. Recently, more fields of application have opened up for CMCs, in which environmental impacts are relevant. These impacts have barely been investigated so far but receive growing interest due to increasing awareness of the environmental consequences. Our innovative approach frames material properties in relation to environmental impacts (e.g., global warming potential in CO₂ emission) by varying process parameters to balance optimum performance against environmental considerations. First, the process of wet filament winding has been investigated up to the Carbon Fiber Reinforced Plastic (CFRP) state by changing both the curing and tempering temperatures. During the production of CFRP plates, mass and energy flows were tracked in each step. Three point-bending and interlaminar shear tests have been performed on the resulting samples to identify basic mechanical properties. The environmental impacts are determined by a cradle-to-gate Life Cycle Assessment (LCA), using the software SimaPro. The resulting tradeoffs between mechanical properties and environmental impacts show nonlinear behavior, thus revealing optimum points above which improved mechanical properties are associated with significantly higher CO₂ emissions.     

Pheromone responsiveness is regulated by components of the Gpr1p‐mediated glucose sensing pathway in Saccharomyces cerevisiae

Many fungi have evolved mechanisms to assess environmental nutrient availability prior to the energy‐intensive process of mating. In this study, we examined one such system in Saccharomyces cerevisiae, involving a glucose‐sensing pathway mediated by Gpr1p and the pheromone‐induced mating pathway. Initially we observed that the mating pathway in MATa cells is sensitive to environmental glucose depletion. This phenomenon can be partially reversed with a high glucose spike, but not with the addition of low levels of glucose. Deletion of the low‐affinity glucose receptor, Gpr1p, eliminated this glucose‐induced recovery of pheromone responsiveness. We then determined the impact of GPR1 deletion on the mating pathway and observed that, in all end points studied, the mating pathway response to pheromone is reduced in the absence of Gpr1p. Similarly, elimination of the Gα for Gpr1p, Gpa2p, resulted in reduction in pheromone sensitivity in all assays studied. The negative effect of removing Gpr1p on mating pathway activation could be recovered by overexpressing the mating receptor, Ste2p. Furthermore, Ste2p levels are reduced in the absence of glucose and GPR1. These data suggest that activity of the GPCR‐mediated mating pathway in S. cerevisiae is modulated by extracellular glucose concentrations through the only other GPCR in MATa cells, Gpr1p. Copyright © 2014 John Wiley & Sons, Ltd.     

Fluorine in Drug Design: A Case Study with Fluoroanisoles

Anisole and fluoroanisoles display distinct conformational preferences, as evident from a survey of their crystal structures. In addition to altering the free ligand conformation, various degrees of fluorination have a strong impact on physicochemical and pharmacokinetic properties. Analysis of anisole and fluoroanisole matched molecular pairs in the Pfizer corporate database reveals interesting trends: 1) PhOCF₃ increases log D by ～1 log unit over PhOCH₃ compounds; 2) PhOCF₃ shows lower passive permeability despite its higher lipophilicity; and 3) PhOCF₃ does not appreciably improve metabolic stability over PhOCH₃. Emerging from the investigation, difluoroanisole (PhOCF₂H) strikes a better balance of properties with noticeable advantages of log D and transcellular permeability over PhOCF₃. Synthetic assessment illustrates that the routes to access difluoroanisoles are often more straightforward than those for trifluoroanisoles. Whereas replacing PhOCH₃ with PhOCF₃ is a common tactic to optimize ADME properties, our analysis suggests PhOCF₂H may be a more attractive alternative, and greater exploitation of this motif is recommended.     

An FTIR study of the induction and release of kiwifruit buds from dormancy

BACKGROUND: Many deciduous, perennial fruit crops require winter chilling for adequate budbreak and flowering. Recent research has shown that changes in sugar and amino acid profiles are associated with the release of buds from dormancy. This paper uses FTIR spectrometry to provide an alternative mechanism for tracking metabolic changes in the meristems of kiwifruit buds during winter dormancy. The results suggest that the application of multivariate analysis to FTIR spectra has the potential to be a reliable and fast method for detecting structural and compositional changes in fruit crops. RESULTS: Ten wave numbers of the FTIR spectra are used to calculate a bud development function. This function has been validated using data from two seasons and four orchards, and by monitoring the effects of hydrogen cyanamide application, sugar concentrations and soil temperatures on this function. These wave numbers appear to be associated with carbohydrate, pectin and cellulose levels in the meristems. CONCLUSION: It is expected that this FTIR signature can be used to advance our understanding of the influence of the various environmental and physiological factors on the breaking of bud dormancy and shoot outgrowth, including the optimum timing and concentrations of applications of budbreak regulators, such as hydrogen cyanamide. Copyright © 2010 Society of Chemical Industry     

Interaction analysis and geometric interconnection decoupling for networks of process systems

The effects of interactions between nonlinear subprocesses on the stabilizability of plantwide systems via the concept of dissipative systems are studied. Conditions for which controlled variables of each interconnected subprocess can be driven to and maintained at their desired values are established through the application of interconnection decoupling techniques. The resulting decoupling feedback law encodes the interaction effects between subprocesses and determines the required information structure for achieving desired control performance using distributed control laws. The proposed constructive approach leads to new criteria for the selection of manipulated and controlled variables that guarantee plantwide stability. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2795–2809, 2013     

Influence of hydrodynamics and pulse plating parameters on the electrocodeposition of nickel-alumina nanocomposite films

Nickel-alumina nanocomposites were produced by electrocodeposition utilizing two electrode configurations, a parallel plate electrode (PPE) and impinging jet electrode (IJE), and various current modulations, i.e. direct current (DC), pulse plating (PP) and pulse reverse plating (PRP). Particle incorporation increased linearly with the particle loading of the electrolyte for all deposition conditions studied. A maximum incorporation of 12 vol.% of 50 nm γ-Al₂O₃ particles in a nickel matrix was achieved using an unsubmerged IJE system, while PP and PRP resulted in composites with particle contents up to 11 vol.% of 13 nm γ-Al₂O₃ particles. In general, nanocomposites showed higher hardness compared to the pure nickel coatings. The enhanced hardness of the composite films was associated with modifications in the microstructure of the nickel matrix as well as with the nanoparticle incorporation. The pure nickel deposits exhibited a strong (1 0 0) texture. With increasing plating current density and particle incorporation, a variation in the crystallite size and a loss of texture was observed.     

Why psychologists must change the way they analyze their data: The case of psi: Comment on Bem (2011).

Does psi exist? D. J. Bem (2011) conducted 9 studies with over 1,000 participants in an attempt to demonstrate that future events retroactively affect people's responses. Here we discuss several limitations of Bem's experiments on psi; in particular, we show that the data analysis was partly exploratory and that one-sided p values may overstate the statistical evidence against the null hypothesis. We reanalyze Bem's data with a default Bayesian t test and show that the evidence for psi is weak to nonexistent. We argue that in order to convince a skeptical audience of a controversial claim, one needs to conduct strictly confirmatory studies and analyze the results with statistical tests that are conservative rather than liberal. We conclude that Bem's p values do not indicate evidence in favor of precognition; instead, they indicate that experimental psychologists need to change the way they conduct their experiments and analyze their data. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Demand side resource operation on the Irish power system with high wind power penetration

The utilisation of demand side resources is set to increase over the coming years with the advent of advanced metering infrastructure, home area networks and the promotion of increased energy efficiency. Demand side resources are proposed as an energy resource that, through aggregation, can form part of the power system plant mix and contribute to the flexible operation of a power system. A model for demand side resources is proposed here that captures its key characteristics for commitment and dispatch calculations. The model is tested on the all island Irish power system, and the operation of the model is simulated over one year in both a stochastic and deterministic mode, to illustrate the impact of wind and load uncertainty. The results illustrate that demand side resources can contribute to the efficient, flexible operation of systems with high penetrations of wind by replacing some of the functions of conventional peaking plant. Demand side resources are also shown to be capable of improving the reliability of the system, with reserve capability identified as a key requirement in this respect.