Critical boundaries in the early Drosophila embryo are set by morphogenetic gradients. A new quantitative study shows that the placement of one such boundary is more accurate than the gradient thought to set it. Genetic analysis of the accuracy of the process implicates a gene not previously thought to be involved., Peer-reviewed article, Published.
Thermal Performance of Exterior Envelopes of Whole Buildings X International Conference, Clearwater Beach, Florida, USA, December 02, 2007. This climate sensitivity study studied the effects of wind-driven rain on a stucco-clad wall using the advanced hygrothermal model, hygIRC. Simulations were made for a number of climatic conditions based on the moisture index (MI) and for amounts of water deposited inside a wall. The moisture index was based on the severity of a given climate in respect to wall assemblies and the degree of wetting and drying to which a wall could potentially be subjected. The failure criteria was the concurrent occurrence of temperature and relative humidity above thresholds of 10oC and 95% respectively, for ninety consecutive days at any location of wood-based material in the wall., Conference paper, Published. A version of this document is published in: Thermal Performance of Exterior Envelopes of Whole Buildings X International Conference, Clearwater Beach, FL., Dec. 2-7, 2007, pp. 1-15.
Quality of botanical products and raw materials is important to manufacturers, regulators, researchers, and consumers. Many modern botanical quality-assurance schemes set specifications for select phytochemicals and measure against those specifications as one determinant of quality. While numerous publications describe procedures for determining compounds of interest in plant species, few methods have been systematically evaluated for accuracy, precision, or reliability, and often the analysis of finished products is not within the scope of the method. Hydrastis canadensis L., commonly referred to as Goldenseal, is an economically important North American medicinal plant that has been subject to adulteration in commerce. The phytochemicals of interest in the plant are the alkaloids hydrastine, berberine, and canadine. Of interest is also palmatine, an alkaloid found in potential adulterant species but not in goldenseal. In this study, goldenseal materials in raw, capsule, and tablet form, including an Echinacea/ Goldenseal combination product, were extracted with acidified water and acetonitrile and their hydrastine, berberine, canadine, and palmitine content determined by HPLC. The analytical method was optimized and evaluated in a single-laboratory validation study. Calibration curves for hydrastine and berberine were linear from 10 to 150 μ g/mL. The limits of detection for palmatine and canadine were determined to be 0.5 μ g/mL, which translates to detection of levels of 0.004% w/w in test samples. Chromatographic resolution was achieved for all analytes in an isocratic 12.5-min chromatographic run employing a binary mobile phase. Triplicate determinations performed on 10 test materials by two analysts on 3 days resulted in relative standard deviations ranging from 0.9% to 3.4%., Peer-reviewed article, Published.
This paper aims to present a novel smart grid adaptive energy conservation and optimization engine for smart distribution networks. The optimization engine presented in this paper tries to minimize distribution network loss, improve voltage profile of the system and minimize the operating cost of reactive power injection by switchable shunt Capacitor Banks using Advanced Metering Infrastructure data. Moreover, it performs Conservation Voltage Reduction (CVR) and minimizes transformer loss. To accurately weight the optimization engine objective function sub-parts, Fuzzification technique is employed in this paper. Particle Swarm Optimization (PSO) is applied as Volt-VAR Optimization (VVO) algorithm. Substantial benefits of the proposed energy conservation and optimization engine include but not limited to: adequate accuracy and speed, comprehensive objective function, capability of using AMI data as inputs, and ability to determine weighting factors according to the cost of each objective sub-part. To precisely test the applicability of proposed engine, 33-node distribution feeder is used as case study. The result analysis shows that the proposed approach could lead distribution grids to achieve higher levels of optimization and efficiency compared with conventional techniques., Article, Published. Received 27 November 2015, Revised 13 April 2016, Accepted 16 April 2016, Available online 26 April 2016.
In recent years, smart grid technologies such as Distribution Management Systems (DMS) and Advanced Metering Infrastructure (AMI) have created remarkable opportunities for distribution grids in terms of operation, control and optimization. The advent of AMI has created considerable amount of data that can be used in optimization applications. Other smart grid functionalities could increase the performance of energy conservation and optimization solutions. As such, this paper aims to review the main requirements of two important smart grid adaptive energy conservation and optimization solutions called Volt-VAR Optimization and Conservation Voltage Reduction, in terms of control, measurement, communication and standards for grids., Article, Published. Received 13 May 2016, Revised 13 September 2016, Accepted 22 September 2016, Available online 3 October 2016.
While there is debate around the real causes of Climate Change, Green House Gas (GHG) emissions as a result of widespread use of fossil-based fuels by major economies around the world has been thought of playing a significant role in perpetuating the negative impacts of the phenomenon known as Climate Change. Regardless of whether GHG emissions is the sole culprit of the unusual, and often devastating changes in the climate patterns around the world, the global understanding has been sought over mitigating further dependence on fossil fuels by the developed countries. What further accentuates that desire, is not only the political and social instability of the regions which have traditionally supplied such fuels, but the fact that such fuel are finite in nature and due to be substantially exhausted in the not too distant future. It is interesting to note that the political and social turmoil associated with traditional sources of fossil fuels has given rise to the justification for many special interest groups in the developed world to call for "drilling closer to home". This view often ignores the fact that fossil fuel in the developed world often lies in "difficult to reach" and technologically challenging areas, which do not lend themselves to relatively risk-free exploration and exploitation. Recent environmental disasters, such as the oil spill in the Gulf of Mexico is a clear and undisputable indication of the dangers associated with "drilling closer to home". Consequently, to get out of our energy conundrum, it seems that our societies have no choice but to review and question the way our economies generate and utilize energy. Most studies of this nature reveal the wasteful and unsustainable processes and approaches which we have so far used in energy production and use. Conversion of one form of energy into another, transmission of energy from one place to another, distribution of energy through our urban and rural communities, and management of energy resources have all been imperfect, to say the least. Such wasteful approaches to energy use have been the hallmark of the last century, which has now come back to haunt us in terms of devastating consequences associated with Climate Change. It is in that light that Smart Grid has been inadvertently positioned as the silver bullet to address the Climate Change and Energy Independence issues. Smart Grid is expected to enable unprecedented degrees of conservation, efficiencies and utilization of alternative sources of energy, thus substantially reducing this century's dependence on fossil fuels. It is notable that regardless of which development category they belong to, the developed countries, as well as the developing countries, have put together ambitious plans for the development of next generation electric grid, also called Smart Grid, as the main engine for the development of their economies and the well-being of their population. However, the fact remains that Smart Grid is still a collection of concepts and ideas, whose full impact cannot be realized until a rich portfolio of innovative technologies, system architectures, integration solutions and social-economic components are available cost-effectively and in concert to address the energy supply and demand issues which individual countries across the world are grappling with. And as such, energy independence should be perceived by the world community as a global problem longing for global solutions. As will be demonstrated in the rest of this chapter, Information and Communication Technologies are poised to play a critical role in bringing about the full spectrum of functionalities which Smart Grid promises. After all, Smart Grid is all about pervasive monitoring and control, which could not be realized without a comprehensive blanket of communication technologies, encompassing all utility assets, and enabling the intelligence implanted in each node to contribute to the overall system capabilities and functionalities which Smart Grid is expected to provide., book chapter, Book published
The utility sector's transition to renewable energy and the smart grid has already begun. The first step towards smart grid is microgrid, which is a smaller electricity grid with access to all the essential assets of a larger grid. This book provides a glimpse into an actual microgrid project. It supplies a system-level approach to the design of smart Microgrids, covering the entire design process-from roadmap to realization. Detailing lessons learned and pitfalls to avoid in Microgrid technology, the book provides an interdisciplinary approach to design and problem solving for smart microgrids., Book, Published.
Physical activity (PA) must be performed regularly to accrue health benefits. However, the majority of manual wheelchair users do not meet PA recommendations. Existing community-based PA programs for manual wheelchair users appear to work, but effect sizes are small and retention is low. Existing PA programs may not fully implement some psychosocial factors that are strongly linked with PA (eg, autonomy). The use of peers and mobile phone technology in the Smartphone Peer PA Counseling (SPPAC) program represents a novel approach to cultivating a PA-supportive environment for manual wheelchair users., Peer-reviewed article, Published.
A study was conducted to review the acoustical features and the potential contributions of green roofs to the acoustical environment, to investigate sound transmission theory, and to report on new empirical findings on the transmission loss of green roofs. The results of the study shows that existing sound transmission algorithms do not adequately predict TL of light-weight roof system or green roofs, nor describe the potential effect of moisture content of the substrate. The sound energy is dissipated in the substrate and provides a mass loading and damping effect on to the light-weight roof deck. The study also suggested that green roofs will provide a higher TL than the additional ceiling element and improve TL throughout the full architectural frequency range, specifically desirable in residential and institutional occupancies that are developed below aircraft flight paths., Article, Published.
During embryonic development, the positional information provided by concentration gradients of maternal factors directs pattern formation by providing spatially dependent cues for gene expression. In the fruit fly, Drosophila melanogaster, a classic example of this is the sharp on-off activation of the hunchback (hb) gene at midembryo, in response to local concentrations of the smooth anterior-posterior Bicoid (Bcd) gradient. The regulatory region for hb contains multiple binding sites for the Bcd protein as well as multiple binding sites for the Hb protein. Some previous studies have suggested that Bcd is sufficient for properly sharpened Hb expression, yet other evidence suggests a need for additional regulation. We experimentally quantified the dynamics of hb gene expression in flies that were wild-type, were mutant for hb self-regulation or Bcd binding, or contained an artificial promoter construct consisting of six Bcd and two Hb sites. In addition to these experiments, we developed a reaction-diffusion model of hb transcription, with Bcd cooperative binding and hb self-regulation, and used Zero Eigenvalue Analysis to look for multiple stationary states in the reaction network. Our model reproduces the hb developmental dynamics and correctly predicts the mutant patterns. Analysis of our model indicates that the Hb sharpness can be produced by spatial bistability, in which hb self-regulation produces two stable levels of expression. In the absence of self-regulation, the bistable behavior vanishes and Hb sharpness is disrupted. Bcd cooperative binding affects the position where bistability occurs but is not itself sufficient for a sharp Hb pattern. Our results show that the control of Hb sharpness and positioning, by hb self-regulation and Bcd cooperativity, respectively, are separate processes that can be altered independently. Our model, which matches the changes in Hb position and sharpness observed in different experiments, provides a theoretical framework for understanding the data and in particular indicates that spatial bistability can play a central role in threshold-dependent reading mechanisms of positional information., Peer-reviewed article, Published. Received October 16, 2007; Accepted August 13, 2008; Published September 26, 2008.
Proceedings of the 18th IEEE Symposium on Logic in Computer Science (LICS-03), Ottawa, ON, 2003. The spectrum of a first-order sentence is the set of cardinalities of its finite models. Relatively little is known about the subclasses of spectra that are obtained by looking only at sentences with a specific signature. In this paper, we study natural subclasses of spectra and their closure properties under simple subdiagonal functions. We show that many natural closure properties turn out to be equivalent to the collapse of potential spectrum hierarchies. We prove all of our results using explicit transformations on first-order structures., Conference paper, Published.
Thee aim of this chapter is to provide the reader with a general overview of the different phenomena and factors involved with durability of repair and suggest the major aspects which the repair design should focus on. However, it is important to keep in mind that any repair problem needs to be addressed as a unique problem ﬁrst, and the designer, by developing awareness of the several challenges involved, should be able to make mindful choices, adequate to the specific application that is being considered., Book chapter, Published.