Preliminary Performance Assessment Research Articles

Energy retrofit techniques: An experimental study of two typical school buildings in Tehran

Energy retrofit of educational buildings is an effective solution to the high energy consumption and thermal discomfort problems in this sector. This article presents the retrofit procedure of two typical schools built before and after 2000 in Iran. The procedure contains three steps: first preliminary building performance assessment and presenting retrofit proposals, second optimizing and prioritizing scenarios based on energy simulation and payback time (PBT), and third assessment of the implemented techniques. Energy modeling and PBT analysis indicate air tightening, window replacement, and roof insulation are among the most efficient scenarios for implementation. The selected measures are implemented and the energy consumption and thermal environment of the schools were monitored in order to assess the energy target achievements. In addition to 29.87% and 38.29% primary energy reduction observed after retrofit implementations in the old and new cases respectively, questionnaire surveys approved indoor environmental quality enhancements. As a pilot study the results show that the proposed method could support the decision making process in future retrofit projects.

Development and validation of trauma surgical skills metrics: Preliminary assessment of performance after training.

Maintaining trauma-specific surgical skills is an ongoing challenge for surgical training programs. An objective assessment of surgical skills is needed. We hypothesized that a validated surgical performance assessment tool could detect differences following a training intervention. We developed surgical performance assessment metrics based on discussion with expert trauma surgeons, video review of 10 experts and 10 novice surgeons performing three vascular exposure procedures and lower extremity fasciotomy on cadavers, and validated the metrics with interrater reliability testing by five reviewers blinded to level of expertise and a consensus conference. We tested these performance metrics in 12 surgical residents (Year 3-7) before and 2 weeks after vascular exposure skills training in the Advanced Surgical Skills for Exposure in Trauma (ASSET) course. Performance was assessed in three areas as follows: knowledge (anatomic, management), procedure steps, and technical skills. Time to completion of procedures was recorded, and these metrics were combined into a single performance score, the Trauma Readiness Index (TRI). Wilcoxon matched-pairs signed-ranks test compared pretraining/posttraining effects. Mean time to complete procedures decreased by 4.3 minutes (from 13.4 minutes to 9.1 minutes). The performance component most improved by the 1-day skills training was procedure steps, completion of which increased by 21%. Technical skill scores improved by 12%. Overall knowledge improved by 3%, with 18% improvement in anatomic knowledge. TRI increased significantly from 50% to 64% with ASSET training. Interrater reliability of the surgical performance assessment metrics was validated with single intraclass correlation coefficient of 0.7 to 0.98. A trauma-relevant surgical performance assessment detected improvements in specific procedure steps and anatomic knowledge taught during a 1-day course, quantified by the TRI. ASSET training reduced time to complete vascular control by one third. Future applications include assessing specific skills in a larger surgeon cohort, assessing military surgical readiness, and quantifying skill degradation with time since training.

Steady-state analytical models for performance assessment of landfill composite liners.

One-dimensional mathematical models were developed for organic contaminant transport through landfill composite liners consisting of a geomembrane (GM) and a geosynthetic clay liner (GCL) or a GM and a compacted clay liner (CCL). The combined effect of leakage through GM defects, diffusion in GM and the underlying soil liners, and degradation in soil liners were considered. Steady state analytical solutions were provided for the proposed mathematical models, which consider the different combinations of advection, diffusion, and degradation. The analytical solutions of the time lag for contaminant transport in the composite liners were also derived. The performance of GM/GCL and GM/CCL was analyzed. For GM/GCL, the bottom flux can be reduced by a factor of 4 when the leachate head decreases from 10 to 0.3 m. The influence of degradation can be ignored for GM/GCL. For GM/CCL, when the leachate head decreases from 10 to 0.3 m, the bottom flux decreases by a factor of 2-4. Leachate head has greater influence on bottom flux in case of larger degradation rate (e.g., half-life = 1 year) compared to the case with lower degradation rate (e.g., half-life = 10 years). As contaminant half-life in soil liner decreases from 10 to 1 year, bottom flux decreases by approximately 2.7 magnitudes of orders. It is indicated that degradation may have greater influence on time lag of composite liner than leachate head. As leachate head increases from zero to 10 m, time lag for GM/CCL can be reduced by 5-6 years. Time lag for the same composite liner can be reduced by 10-11 years as contaminant half-life decreases from 10 to 1 year. Reducing leachate head acting on composite liners and increasing the degradation capacity of the soil liner would be the effective methods to improve the performance of the composite liners. The proposed analytical solutions are relatively simple and can be used for preliminary design and performance assessment of composite liners.

Nuclear waste transmutation performance assessment of an accelerator driven subcritical reactor for waste transmutation (ADS-NWT)

As a concept of lead–bismuth cooled accelerator driven sub-critical reactor, ADS-NWT was proposed for nuclear waste transmutation by FDS Team. In this paper, preliminary transmutation performance assessment on ADS-NWT was performed by using metallic dispersion fuel and metal alloy fuel. The studies were committed to improving the Discharge Transmutation Support Ratio (DTSR) under three key design constraints. Subject to the design constraints on the effective multiplication factor, the peak linear power and the peak fast neutron fluence, the design studies had been performed for ADS-NWT blanket. From these studies, the results showed that the maximum DTSR was primarily related to the MA/Pu ratio, the peak fast neutron fluence and fuel design under imposed design constraints. The maximum DTSR could be ∼47 in one refueling cycle time when the thermal power was fixed to 1000MW and the effective multiplication factor was 0.98 based on the specific design.

A Bayesian Approach to Oil Slicks Edge Detection Based on SAR Data

This paper proposes a Bayesian edge detector to be fed by polarimetric, possibly multifrequency, synthetic aperture radar (SAR) data. It can be used to detect dark spots on the ocean surface and, hence, as the first stage of a system for identification and monitoring of oil slicks. The proposed detector does not require secondary data (i.e., pixels from a slick-free area) but for a certain a priori knowledge; remarkably, a preliminary performance assessment, based on both synthetic and real SAR recordings, shows that it has a slightly better performance in terms of detection and false alarm control than previously proposed classical (i.e., non-Bayesian) detectors.

Preliminary Performance Assessment of TV White Spaces Technology for Broadband Communication in Malawi

Recently, the use of TV White Spaces for broadband communication has raised interest. White Spaces refer to regions of radio spectrum that are not used all the time in a specific geographical location. This paper presents the preliminary performance assessment of a TV White Spaces deployment in Malawi. The method used involved coverage simulations at the TV White Spaces frequencies, deployment of the network, monitoring and performance analysis. The preliminary results report usable coverage distance up to 7.5km which has allowed that remote students access the content of the university library and interact with the university faculty. The results thus show that the TV White Spaces technology can be used for broadband connectivity in rural and undeserved areas even when the WiFi and broadcasting spectrum is already utilized. A typical application that supports remote access of e-library resources from a rural Secondary School was developed using DSpace architecture over the White Spaces infrastructure is discussed.

Theoretical Analysis of the Combination of CSP with a Biomass CHP-plant Using ORC-technology in Central Europe

In this paper the results of the preliminary performance assessment of an emerging hybrid CHP-technology using Organic- Rankine-Cycle technology comprising biomass combustion and concentrating solar thermal power in areas with low DNI is presented. The study was conducted in course of the research project BIOconSOLAR, which was funded by the climate fund of the Austrian government. The assessment is based on the technical design and economic conditions of an existing CHP-plant with nominal electric power output of 1.5 MW, which is located in the city Salzburg in Austria. The solar thermal energy provided by a parabolic trough collector field is primary used for electric power production in order to reduce biomass consumption and operation costs accordingly, but also to boost the thermal energy supply for the district heating of the city Salzburg. For electric power production the solar thermal energy is fed into the ORC-power cycle at a temperature level of at least 270°C. A transient simulation model of both the biomass CHP-plant and the parabolic trough plant was developed in IPSEpro. Based on the results of the process simulation the economic performance was assessed by conducting a dynamic investment calculation. Despite the technical and economic uncertainties of this preliminary assessment the retrofitting of biomass-solar CHP-plants with CSP in areas with low DNI is a promising option to improve the economic performance of about 100 CHP-plants in operation in Central Europe. A feed-in-tariff for solar thermal electricity in the same order of magnitude as for photovoltaic could trigger the retrofit of biomass CHP-plants.

Geoid Determination in South Korea from a Combination of Terrestrial and Airborne Gravity Anomaly Data

The determination of the geoid in South Korea is a national imperative for the modernization of height datums, specifically the orthometric height and the dynamic height, that are used to monitor hydrological systems and environments with accuracy and easy revision, if necessary. The geometric heights above a reference ellipsoid, routinely obtained by GPS, lead immediately to vertical control with respect to the geoid for hydrological purposes if the geoid height above the ellipsoid is known accurately. The geoid height is determined from gravimetric data, traditionally ground data, but in recent times also from airborne data. This paper illustrates the basic concepts for combining these two types of data and gives a preliminary performance assessment of either set or their combination for the determination of the geoid in South Korea. It is shown that the most critical aspect of the combination is the gravitational effect of the topographic masses above the geoid, which, if not properly taken into account, introduces a significant bias of about 8 mgal in the gravity anomalies, and which can lead to geoid height bias errors of up to 10 cm. It is further confirmed and concluded that achieving better than 5 cm precision in geoid heights from gravimetry remains a challenge that can be surmounted only with the proper combination of terrestrial and airborne data, thus realizing higher data resolution over most of South Korea than currently available solely from the airborne data.

SuDS Efficiency during the Start‐Up Period under Mediterranean Climatic Conditions

This paper presents the performance of a number of sustainable drainage systems (SuDS) in the city of Xàtiva in the Valencia Region of Spain relatively soon after their construction. The systems studied comprise two roadside swales, one detention basin receiving runoff from one of the swales and one green roof to a school. The SuDS were installed under an EU LIFE+ project intended to demonstrate their practicability, application, and behavior under Mediterranean rainfall conditions. Most of the systems installed were in new developments but the green roof was retrofitted to a school within Xàtiva, which is a dense urban area. Full flow monitoring was undertaken and spot samples were taken to give a preliminary assessment of water quality performance. The early results presented in the paper demonstrate the effectiveness of the systems under typical Mediterranean conditions, which comprise intense rainfall from September to December and little or no precipitation at other times of the year. It is concluded that SuDS can be effectively introduced in the Mediterranean region of Spain.

Preliminary performance assessment of computer automated facial approximations using computed tomography scans of living individuals

ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a computer-automated facial approximation application jointly developed by the Federal Bureau of Investigation and GE Global Research. The application derives a statistically based approximation of a face from a unidentified skull using a dataset of ∼400 human head computer tomography (CT) scans of living adult American individuals from four ancestry groups: African, Asian, European and Hispanic (self-identified). To date only one unpublished subjective recognition study has been conducted using ReFace approximations. It indicated that approximations produced by ReFace were recognized above chance rates (10%). This preliminary study assesses: (i) the recognizability of five ReFace approximations; (ii) the recognizability of CT-derived skin surface replicas of the same individuals whose skulls were used to create the ReFace approximations; and (iii) the relationship between recognition performance and resemblance ratings of target individuals. All five skin surface replicas were recognized at rates statistically significant above chance (22–50%). Four of five ReFace approximations were recognized above chance (5–18%), although with statistical significance only at the higher rate. Such results suggest reconsideration of the usefulness of the type of output format utilized in this study, particularly in regard to facial approximations employed as a means of identifying unknown individuals.

Investigating wastewater modelling as a tool to predict anaerobic decomposition and biogas yield of abattoir effluent

Due to the high strength nature of abattoir wastewater, the accumulation of crusts on anaerobic ponds is a systemic problem in the red meat processing industry in Australia and can limit the ability to accurately obtain biogas measurements. In this study, BioWin was used to simulate chemical oxygen demand (COD) removal rates and subsequent biogas production rate based on field data from two abattoirs where crust accumulation was an issue. BioWin is a Microsoft Windows-based simulator developed by EnviroSim Associates Ltd, which has seen use in the design and optimisation of wastewater treatment plants. In assessing overall anaerobic decomposition efficiency it was hypothesised that a large percentage of influent COD was present as a surface crust which remained largely unbiodegradable. Field data effluent COD removal rates were matched to simulated rates predicted by BioWin when measured influent COD was reduced to 30% (absolute relative error of 11–14%), thus supporting the notion that a significant portion of COD is not taking part in the anaerobic digestion process. The simulation provides a preliminary assessment of pond performance in terms of COD removal rates and also subsequent biogas production rates. BioWin was able to predict approximate biogas production rates ranging between 113 to 173m3/d and 52m3/d for the two abattoirs investigated. Further work to validate simulation using BioWin includes obtaining actual biogas measurements and performing COD measurement of crust.

In-flight calibration and verification of the Planck-LFI instrument

In this paper we discuss the Planck-LFI in-flight calibration campaign. After a brief overview of the ground test campaigns, we describe in detail the calibration and performance verification (CPV) phase, carried out in space during and just after the cool-down of LFI. We discuss in detail the functionality verification, the tuning of the front-end and warm electronics, the preliminary performance assessment and the thermal susceptibility tests. The logic, sequence, goals and results of the in-flight tests are discussed. All the calibration activities were successfully carried out and the instrument response was comparable to the one observed on ground. For some channels the in-flight tuning activity allowed us to improve significantly the noise performance.

An active hearing protection device for musicians

Professional musicians have to deal with two great problems when wearing hearing protection devices (HPDs): the occlusion effect and the isolation effect. The occlusion effect is an unnatural and annoying perception of one’s own voice when wearing HPDs. It will affect all musicians whose instrument induces vibrations to the skull, including a singer's vocal tracts and instruments mechanically coupled to the head, such as a trumpet or a violin. The isolation effect is the unnatural sensation of being isolated from a given sound environment. It is caused by a non-uniform attenuation of the HPD over the frequency spectrum and the absence of compensation for psychoacoustic factors, such as uneven loudness perception. These two effects cause a shift of perception between the musician's perception and the audience's perception and therefore compromise the musician’s ability to offer a good performance to his audience. This paper presents the design and implementation of an active musician’s HPD featuring a feedback active noise control system for occlusion effect reduction as well as psychoacoustic compensations for isolation effect reduction. The proposed test procedure and preliminary performance assessments are presented to validate both the test procedure and the system for future subjects trials on a larger scale.

Batch tracking algorithm for multistatic sonars

In this study, the authors propose a new tracking algorithm for multistatic sonar systems, where the measurements collected by different sensors are sent to a fusion centre. The proposed algorithm relies on the main idea behind the track-before-detect paradigm, which consists of processing data from several consecutive pings, and estimates target positions by maximising the likelihood function of the available measurements. The authors assume that one manoeuvring target is present within the surveillance area. The preliminary performance assessment, carried out on simulated scenarios, shows that the proposed algorithm has acceptable performance also when the probability of detection per sensor is low (in the order of 0.3) and measurement errors are significant.

Contractile Hydrostatically Coupled Dielectric Elastomer Actuators

The so-called hydrostatically coupled dielectric elastomer actuators (HC-DEAs) have recently been described as a means to improve versatility and safety of electroactive polymer actuators made of DEs. HC-DEAs use an incompressible fluid that mechanically couples a DE-based active part to a passive part interfaced to the load. In this paper, we present the ongoing development of linear contractile HC-DEAs. The actuator is made of two rigid disks (circular frames) that support an active membrane, consisting of a DE film coated with compliant electrodes. The frames and the membrane delimit a closed chamber, filled with the fluid. The pressure of the fluid is used to provide the actuator with a barrel-like shape, while keeping the length of the structure limited by a counteracting element (such as an internal spring or the external load itself); combining this element with the internal pressure allows the structure to be axially precompressed. As a result of an electrical activation of the membrane, outward radial buckling and related axial contraction of the device are achieved. This paper presents preliminary assessment of static electromechanical performance of prototypes made of silicone and water, studying combined effects of precompression, voltage, and stress relaxation.

Persymmetric Rao and Wald Tests for Partially Homogeneous Environment

This letter deals with the problem of adaptive detection in partially-homogeneous Gaussian disturbance with unknown but persymmetric structured covariance matrix. Since no uniformly most powerful test exists for the problem at hand, we devise and assess two detection strategies based on the Rao test and the Wald test design criteria. Remarkably, both detectors ensure the constant false alarm rate property with respect to both the structure of the covariance matrix as well as the power level. The preliminary performance assessment, conducted by resorting to simulated data, has confirmed the effectiveness of the newly proposed detectors.

Effect of Stocking Density on Growth Performance and Yield of Subadult Pacific Red Snapper Cultured in Floating Sea Cages

AbstractA preliminary assessment of growth performance and yield of subadult Pacific red snapper Lutjanus peru raised in floating sea cages was conducted by measuring fish length, weight, feed conversion, and survival rate during a 120‐d grow‐out trial at Punta el Caballo Beach, Nayarit State, Mexico. Nine floating cages (12.5‐m3 capacity) were used as experimental units. Fish were stocked in triplicate treatment cages at 30, 50, and 70 fish/m3 (1.9, 3.3, and 4.4 kg/m3, respectively) using more than 5,600 wild subadults (mean initial weight ±SD = 63.9 ± 1.4 g) as initial fish stock. Fish were fed twice per day with a sinking commercial pellet, and dissolved oxygen, temperature, pH, transparency, and ammonia nitrogen in each cage were recorded weekly. After 120 d, the mean individual weight at harvest was inversely related to stocking density. Mean final weight, weight gain, and specific growth rate differed among groups, with the highest values recorded for the 30‐fish/m3 density (233.4 ± 5.3 g [mean ± SD], 1.4 g/d, and 1.1% per day, respectively). Mean final body length, feed conversion, condition index, and survival did not differ among density treatments. Net yield (mean ± SD) ranged from 5.0 ± 0.2 kg/m3 (30‐fish/m3 treatment) to 7.9 ± 0.3 kg/m3 (70‐fish/m3 treatment) and differed among the treatments. Considering the initial biomass and density, the 70‐fish/m3 treatment produced a higher total biomass (mean ± SD = 152.9 ± 2.4 kg) but a lower average weight than the 50‐ and 30‐fish/m3 treatments. Our findings suggest that at all stocking densities tested, subadult Pacific red snapper will grow in floating sea cages without significant mortalities. A benefit–cost analysis must be achieved to define the best treatment in economic terms.

Preliminary Study on a Wide-Speed-Range Helicopter Rotor/Turboshaft System

this paper, a preliminary performance assessment of the coupling between a wide-speed-range helicopter rotor and the connected turboshaft engine was carried out. For this purpose, a well-known test case has been chosen (UH-60A helicopter equipped with a GE-T700 engine) to study the implications of such coupling from both the helicopter and theengineviewpoints.Asimple helicopterrotorcalculationmodelisusedtodeterminetheoptimumrotorspeedand required rotor power in various flight conditions. Next, these data are used for the engine-performance analysis, which was carried out using a zero-dimensional, block-based validated engine model to determine the fuel weight necessary to accomplish a given simple mission (i.e., to fly in trimmed forward flight for a given time). The results obtained are compared with the baseline helicopter/engine configuration, and the implications of using variablespeed technology are clearly highlighted.

Preliminary Performance Assessment for Deep Borehole Disposal of High-Level Radioactive Waste

ABSTRACTDeep boreholes have been proposed for many decades as an option for permanent disposal of high-level radioactive waste and spent nuclear fuel. Disposal concepts are straightforward, and generally call for drilling boreholes to a depth of four to five kilometers (or more) into crystalline basement rocks. Waste is placed in the lower portion of the hole, and the upper several kilometers of the hole are sealed to provide effective isolation from the biosphere. The potential for excellent long-term performance has been recognized in many previous studies. This paper reports updated results of what is believed to be the first quantitative analysis of releases from a hypothetical disposal borehole repository using the same performance assessment methodology applied to mined geologic repositories for high-level radioactive waste. Analyses begin with a preliminary consideration of a comprehensive list of potentially relevant features, events, and processes (FEPs) and the identification of those FEPs that appear to be most likely to affect long-term performance in deep boreholes. The release pathway selected for preliminary performance assessment modeling is thermally-driven flow and radionuclide transport upwards from the emplacement zone through the borehole seals or the surrounding annulus of disturbed rock. Estimated radionuclide releases from deep borehole disposal of spent nuclear fuel, and the annual radiation doses to hypothetical future humans associated with those releases, are extremely small, indicating that deep boreholes may be a viable alternative to mined repositories for disposal of both high-level radioactive waste and spent nuclear fuel.

Rotary wave-ejector enhanced pulse detonation engine

The use of a non-steady ejector based on wave rotor technology is modeled for pulse detonation engine performance improvement and for compatibility with turbomachinery components in hybrid propulsion systems. The rotary wave ejector device integrates a pulse detonation process with an efficient momentum transfer process in specially shaped channels of a single wave-rotor component. In this paper, a quasi-one-dimensional numerical model is developed to help design the basic geometry and operating parameters of the device. The unsteady combustion and flow processes are simulated and compared with a baseline PDE without ejector enhancement. A preliminary performance assessment is presented for the wave ejector configuration, considering the effect of key geometric parameters, which are selected for high specific impulse. It is shown that the rotary wave ejector concept has significant potential for thrust augmentation relative to a basic pulse detonation engine.