Measurement and verification strategies for energy savings certificates: meeting the challenges of an uncertain world

End-use energy efficiency is a cost-effective and rapidly deployable strategy for significantly reducing greenhouse gas (GHG) emissions and energy costs. Energy savings certificates (ESCs)—instruments assigning the property rights to energy savings or attributes of those savings—are becoming an effective tool for meeting energy savings and GHG targets. The efficacy of ESCs will depend on the market’s ability to (1) verify the amount of savings that they certify along with the uncertainty of those savings (i.e., quantify their value), (2) clearly assign ownership rights to that value (i.e., state exactly who owns what) and (3) efficiently buy and sell those rights between interested parties (i.e., conduct simple transactions). The measurement and verification (M&V) system governing ESCs will critically impact whether these three criteria are satisfied. An M&V system for ESCs requires the fundamental elements of an M&V system for any regulated energy-efficiency program, but must also address more explicitly the above-mentioned criteria. In this paper, the authors discuss the International Performance Measurement and Verification Protocol (IPMVP) and specific elements of an M&V system that address components of an ESC system.     

Evaluation of plasma natriuretic peptides as markers for left ventricular dysfunction

To test the hypothesis that elevated plasma levels of natriuretic peptides may serve to identify patients with left ventricular (LV) dysfunction, we assessed the predictive diagnostic value of natriuretic peptide levels, in addition to clinical and electro-cardiographic risk factors, as noninvasive indicators of cardiac dysfunction. Plasma levels of atrial natriuretic peptide (cANP) (99-126), N-terminal fragment of proANP (nANP) (26-55), nANP(80-96), brain natriuretic peptide (BNP-32), proBNP(22-46), and C-type natriuretic peptide (CNP-22) were measured in 211 subjects before cardiac catheterization. The strongest correlations with parameters of LV function were found for nANP(80-96) (up to r = -0.55, p < 0.0001), whereas there was no significant correlation with proBNP(22-46) or CNP-22. In patients with LV ejection fractions (LVEF) < or = 45% (n = 38) nANP(26-55), nANP(80-96), cANP(99-126), and BNP-32 were significantly increased (p < 0.001). Partition values for elevated versus normal natriuretic peptide levels were obtained from normal controls and used to separate subjects with and without LV dysfunction. Receiver operating characteristic analysis for LVEF < or = 45% indicated a significantly better diagnostic accuracy for high levels of nANP(80-96), nANP(22-56), cANP(99-126), and BNP-32 than for proBNP and CNP-22. Multivariate analysis by logistic regression identified Q waves and bundle branch block in the electrocardiogram as well as elevated plasma levels of cANP, nANP(80-96), and nANP(26-55) as the strongest independent predictors of low ejection fractions. The relative risk of LV dysfunction was raised up to tenfold in subjects with high natriuretic peptide levels (p < 0.001). The addition of nANP(80-96) and nANP(26-55) to the combination of clinical and electrocardiographic risk factors did not further improve the diagnostic sensitivity for the detection of LVEF < or = 45%, but it markedly increased the overall accuracy (59% to 81%, p < 0.001) and specificity (55% to 81%, p < 0.001). Among natriuretic peptides, elevated nANP(80-96) and nANP(26-55) levels have the strongest impact on the detection of LV dysfunction. They add to the diagnostic information contained in clinical and electrocardiographic factors. Plasma levels alone or in combination with clinical factors seem to be of value for a refined identification of abnormal LV function in the individual patient.     

A 40-GHz static frequency divider with quadrature outputs in 80-nm CMOS

The implemented static frequency divider provides quadrature (Q) clock outputs and divides frequencies up to 44GHz. The core divider circuit consists of two current-mode logic (CML) latches and consumes 3.2mW from a 1.1-V supply. The divided outputs result in a peak-to-peak and rms jitter of 6.3 and 0.8ps, respectively, and the maximum phase mismatch between the in-phase (I) and Q-outputs amounts to 1ps at an input frequency of 40GHz. The high division frequency is achieved by employing resistive loads, inductive peaking, and optimizing the circuit layout for reduced parasitic capacitances in the latches. The core divider consumes a chip area of 30/spl mu/m/spl times/40/spl mu/m only.     

Design of low-power fast VCSEL drivers for high-density links in 90-nm SOI CMOS

The continuous decrease of the supply voltage to 1 V and below in CMOS makes the design of laser drivers a challenging task. Hence, a detailed comparison of three basic driver architectures, namely, common source (CS), CS with source degeneration, and source follower (SF) is presented using transistor models including short channel effects. Based on this comparison, two power-optimized driver topologies are implemented in a 90-nm silicon-on-insulator CMOS technology. The SF driver features a bandwidth of 18 GHz on a 50-/spl Omega/ load. The required chip area is only 140 /spl mu/m/spl times/140 /spl mu/m, which is very beneficial for high-density short-distance optical interconnects. This allows a data rate of 12.5 Gb/s at a bit error ratio of less than 10/sup -12/ to be achieved even with a 10-Gb/s oxide confined vertical-cavity surface-emitting laser (VCSEL). The power consumption is 27 mW. The drivers were optimized for maximal eye opening by applying a fast and accurate VCSEL model.     

Large-band reduction of magnetic vibrations of induction machineswith “breaking-of-impedance” interface

Magnetic vibration of induction machines is reduced, on a large-frequency band, with a breaking-of-impedance interface between stator core and frame. This device is designed with strong tangential stiffness and low radial stiffness. Two-dimensional finite-element (FE) dynamic response is proposed. It is based firstly on experimental determination of magnetic forces with search coils on a half polar pitch on the stator bore. Secondly, all characteristics of windings are determined versus temperature and frequency and homogenized with a linear mixing law. Thirdly, a FE modal analysis is optimized on the target function based on experimental natural frequencies, in order to identify the equivalent mechanical parameters of wound slots     

Laser Patterning Pretreatment before Thermal Spraying: A Technique to Adapt and Control the Surface Topography to Thermomechanical Loading and Materials

Coating characteristics are highly dependent on substrate preparation and spray parameters. Hence, the surface must be adapted mechanically and physicochemically to favor coating–substrate adhesion. Conventional surface preparation methods such as grit blasting are limited by surface embrittlement and produce large plastic deformations throughout the surface, resulting in compressive stress and potential cracks. Among all such methods, laser patterning is suitable to prepare the surface of sensitive materials. No embedded grit particles can be observed, and high-quality coatings are obtained. Finally, laser surface patterning adapts the impacted surface, creating large anchoring area. Optimized surface topographies can then be elaborated according to the material as well as the application. The objective of this study is to compare the adhesive bond strength between two surface preparation methods, namely grit blasting and laser surface patterning, for two material couples used in aerospace applications: 2017 aluminum alloy and AISI 304L stainless steel coated with NiAl and YSZ, respectively. Laser patterning significantly increases adherence values for similar contact area due to mixed-mode (cohesive and adhesive) failure. The coating is locked in the pattern.     

A low-power 20-GHz 52-dB/spl Omega/ transimpedance amplifier in 80-nm CMOS

This paper describes the design of a transimpedance amplifier (TIA) for a low-power, short-distance, high-density fiber-optic interconnect communication system. The single-ended circuit has been designed in an 80-nm digital CMOS process and consumes only 2.2 mW from a 1-V supply. The measured results show a transimpedance gain of 52 dB/spl Omega/ and a large bandwidth of 20 GHz. This work presents the highest bandwidth at the lowest power consumption for CMOS transimpedance amplifiers reported to date.     

Transgastric Doppler echocardiographic assessment of the severity of aortic stenosis using multiplane transesophageal echocardiography

We investigated whether multiplane transesophageal Doppler echocardiography using transgastral views allows determination of pressure gadients and valve areas in patients with aortic stenosis. This technique was feasible in 35 of 39 patients (90%), with highly significant correlations with results obtained from transthoracic Doppler echocardiography and cardiac catheterization, thus offering an alternative approach for quantification of aortic stenosis.