Geometric Aspects of Composite Pulses

Unitary operations acting on a quantum system must be robust against systematic errors in control parameters for reliable quantum computing. Composite pulse technique in nuclear magnetic resonance (NMR) realises such a robust operation by employing a sequence of possibly poor quality pulses. In this article, we demonstrate that two kinds of composite pulses, one compensates for a pulse length error in a one-qubit system and the other compensates for a J-coupling error in a twoqubit system, have vanishing dynamical phase and thereby can be seen as geometric quantum gates, which implement unitary gates by the holonomy associated with dynamics of cyclic vectors defined in the text.Comment: 20 pages, 4 figures. Accepted for publication in Philosophical Transactions of the Royal Society

Program Overview: The Texas LoanSTAR Program; 1989-October 1999, A 10-Year Experience

The Texas LoanSTAR (Loans to Save Taxes and Resources) program was conceived as a $98.6 million capital retrofit program for building energy efficiency. The funding source is petroleum violation escrow funds (PVE) from the Federal government. LoanSTAR is administered by the Texas State Energy Conservation Office of the Comptroller's Office, under the guidance of Dub Taylor, Director, and is the largest revolving loan fund administered by a state for conservation purposes. LoanSTAR was conceived in 1988 and began in 1989. This paper summarizes the program dollar savings and environmental impact from its inception through October 1999

A Methodology to Identify Monthly Energy Use Models from Utility Bill Data for Seasonally Scheduled Buildings: Application to K-12 Schools

The measured energy savings from retrofits in buildings is often determined as the difference between the energy consumption predicted by a baseline model and the measured energy consumption during the post retrofit period. Most baseline models are developed either by regressing the daily energy consumption versus the daily average temperature ( daily model ) or by regressing the monthly energy consumption versus the monthly average temperature ( monthly model ). Savings measurement for buildings such as primary and secondary schools (k-12 school) is very difficult due to the special operating schedules of such buildings. Currently, savings are either determined by simple pre-post utility bill comparison or by a method where by the baseline model consists of two separate models: a 3-P model for non-summer months, and a mean model for the summer months. (Landman, 1996). This paper proposes an improved methodology for identifying baseline models of energy use from utility billing data for buildings such as schools which have important daily and seasonal variations in occupancy. By explicitly considering the occupancy rate in the model, we are able to generalize it and retain the distinction between energy use levels during occupied and unoccupied days of the year. Thus the modified baseline model accounts, not only for the effect of weather, but also for the influence of school schedules. The proposed methodology has been evaluated against the previous 3-P-mean proposed by Landman for 10 schools in Texas for which several years of monitored data are available. Incorporation of scheduling information reduced the average CV of the model from 23.6% using Landman's method to 10.9% using our proposed method

Designing Robust Unitary Gates: Application to Concatenated Composite Pulse

We propose a simple formalism to design unitary gates robust against given systematic errors. This formalism generalizes our previous observation [Y. Kondo and M. Bando, J. Phys. Soc. Jpn. 80, 054002 (2011)] that vanishing dynamical phase in some composite gates is essential to suppress amplitude errors. By employing our formalism, we naturally derive a new composite unitary gate which can be seen as a concatenation of two known composite unitary operations. The obtained unitary gate has high fidelity over a wider range of the error strengths compared to existing composite gates.Comment: 7 pages, 4 figures. Major revision: improved presentation in Sec. 3, references and appendix adde

Report of Energy Efficiency Study and Metering/Utilities Profile for Electricity Deregulation at Prairie View A&M University (PVAMU) Prairie View, Texas

The physical plant director and staff at Prairie View A&M University (PVAMU) do a good job of maintaining PVAMU facilities and keeping expenses down. During our visit, however, we were able to identify several opportunities for improving energy efficiency

A Simple and Quick Chilled Water Loop Balancing for Variable Flow System

For many modem buildings, the chilled water loops and risers are equipped with variable speed pumping systems. How to quickly balance the loop or riser to satisfy the cooling requirement and reduce energy consumption is a very interesting topic today. In this paper, a method for simple and quick balancing of the chilled water risers for a large medical facility has been developed and implemented. Through water loop commissioning, the cold air temperature is maintained very well and the energy consumption for the pumping system is reduced by about 40%

Improving Control of a Dual-Duct Single-Fan Variable Air Volume Systems

This paper discusses improved control strategies for dual-duct single-fan variable air volume (VAV) systems. Common control strategy for supply air volume modulation is evaluated, and an improved air volume control strategy that maintains separate cold and hot air duct static pressure set points is presented. The paper also explores the interactions between the cold and hot deck temperatures and duct static pressures, and discusses the impact of non-ideal deck temperature settings on duct static pressures and overall system energy consumption. To compensate the negative impact of non-ideal cold and hot deck temperature set points, the authors propose using real-time duct static pressure readings as feedback signals to fine-tune the deck temperature set points. These new control schemes can reduce simultaneous cooling and heating while reducing fan power consumption

A Novel Procedure to Determine Optimal Air Static Pressure Set-points and Reset Schedules in VAV Air Handling Units

Air static pressure set-point or schedule for VAV AHLJ systems is one of the most crucial operational parameters for satisfy lug the building load, maintaining the room comfort level and saving energy costs. This paper presents a novel procedure and method, which can be applied to determine the optimal air static pressure set-point for VAV AHUs with both stand-alone controllers and DDC controllers. This procedure provides a simple, fast and a non-intrusive way to obtain the optimal or improved operational schedules without interrupting normal operation of the systems and without detailed simulation. An application example is also presented in this paper

Ex-Vivo 13 C NMR Spectroscopy of Rodent Brain: TNF Restricts Neuronal Utilization of Astrocyte-Derived Metabolites

Tumor necrosis factor (TNF) has well-established roles in neuroinflammatory disorders, but the effect of TNF on the biochemistry of brain cells remains poorly understood. Here, we microinjected TNF into the brain to study its impact on glial and neuronal metabolism (glycolysis, pentose phosphate pathway, citric acid cycle, pyruvate dehydrogenase, and pyruvate carboxylase pathways) using 13C NMR spectroscopy on brain extracts following intravenous [1,2-13C]-glucose (to probe glia and neuron metabolism), [2-13C]-acetate (probing astrocyte-specific metabolites), or [3-13C]-lactate. An increase in [4,5-13C]-glutamine and [2,3-13C]-lactate coupled with a decrease in [4,5-13C]-glutamate was observed in the [1,2-13C]-glucose-infused animals treated with TNF. As glutamine is produced from glutamate by astrocyte-specific glutamine synthetase the increase in [4,5-13C]-glutamine reflects increased production of glutamine by astrocytes. This was confirmed by infusion with astrocyte substrate [2-13C]-acetate. As lactate is metabolized in the brain to produce glutamate, the simultaneous increase in [2,3-13C]-lactate and decrease in [4,5-13C]-glutamate suggests decreased lactate utilization, which was confirmed using [3-13C]-lactate as a metabolic precursor. These results suggest that TNF rearranges the metabolic network, disrupting the energy supply chain perturbing the glutamine-glutamate shuttle between astrocytes and the neurons. These insights pave the way for developing astrocyte-targeted therapeutic strategies aimed at modulating effects of TNF to restore metabolic homeostasis in neuroinflammatory disorders