Real Envelope Research Articles

Experimental method for estimating the effect of solar radiation on the inner surface heat flux of opaque building envelope elements

There still exists a considerable difference when comparing the real and the design energy consumption of buildings. The difference between the design and the real building envelope energy performance is one of its main reasons. The building envelope can be characterised through the individual characterisation of its different building envelope components such as opaque walls or windows. Therefore, the estimation of parameters such as their transmission heat transfer coefficient (UA) and their solar aperture (gA) is usually implemented. Although building components have been analysed over the years, the thermal characteristics of buildings have mainly been estimated through steady-state laboratory tests and simplified calculation/simulation procedures based on theoretical data. The use of inverse modelling based on registered dynamic data has also been used; however, unfortunately, the models used tend to significantly simplify or neglect the solar radiation effect on the inner surface heat flux of opaque building envelope elements. Therefore, this work presents an experimental, dynamic and inverse modelling method that accurately models non-linear phenomena through the use of a user-friendly simulation programme (LORD). The method is able to analyse in detail the effect of the solar radiation on the inner surface heat flux of opaque building envelope elements, without the necessity of knowing their constructive details or thermal properties. The experiment is performed in a fully monitored test box, where different models are tested with different opaque walls to find the best fit. Finally, the solar irradiance signal is removed from the best models so as to accurately quantify the weight of the solar radiation on the inner surface heat flux of each wall for two extreme periods, one for sunny summer days and other for cloudy winter days.

Exploring the efficacy of renewable energy support policies in uncertain environments: A real options analysis

This paper explores the impact of various renewable energy support policies on investor behavior and environmental value. Specifically, the study investigates the effects of fixed feed-in tariff (FIT) and tradable green certificates (TGC) on investor’s flexibility and environmental value under conditions of uncertainty. Real options theory and envelope theory are employed to analyze these uncertainties, with an empirical analysis of China’s electricity market serving as the basis for the study. The results of the analysis demonstrate that the use of TGC can lead to higher environmental value for utility-scale photovoltaic (PV) projects in China. For onshore wind, substituting FIT with TGC may be more appropriate. However, for offshore wind projects, FIT may be more suitable due to their increased vulnerability to uncertainty. Additionally, the study finds that greater support is required for projects deployed under FIT policies.

Are Design Strategies for High-Performance Buildings Really Effective? Results from One Year of Monitoring of Indoor Microclimate and Envelope Performance of a Newly Built nZEB House in Central Italy

As buildings are one of the major contributors to greenhouse gas emissions and energy consumption, they have a key potential for energy efficiency and indoor environmental quality improvement. Therefore, the development of nearly Zero-Energy Buildings (nZEBs) is strategic to respond to these challenges and to design and retrofit sustainable highly performing buildings. Actually, the nZEB target can also be reached with highly insulated wooden technologies. However, they must be critically revised and adapted when taking into account the warm climate peculiarities. The paper contributes to this attempt by dealing with the implementation of a methodology specifically focused on the long-term assessment of the real building envelope performance. The methodology is applied to a recently built wooden nZEB detached single-story dwelling constructed in 2017 in central Italy. One year monitoring data were collected about the envelope in-field dynamic performance and the indoor microclimate and well-being conditions. The theoretical design-stage data and the monitored data were compared. The positive aspects as well as the critical issues of nZEB target in the Mediterranean climate context and the performance gap were underlined. Accordingly, the main aspects to be considered in the design of nZEBs envelope were highlighted.

The Life and Legacy of Danijela Kulezic-Wilson

The Life and Legacy of Danijela Kulezic-Wilson

Improved Pulse Edge Independent Distribution Method for High PAPR High Bandwidth Envelope Tracking Power Supply

Envelope tracking (ET) power supply provides the power amplifier (PA) with a dynamic supply voltage that tracks the envelope of the input signal to the PA, and the final PA efficiency can be greatly improved. With the ever-advancing tracking bandwidth, the switching frequencies of ET power supplies are pushed to be very high and even difficult to be implemented. To address this issue, the pulse edge independent distribution (PEID) method has been proposed. Based on the idea of alternatively working by sets, the control pulses for the multilevel converter are broken into independent rising and falling edges, and rematching them with optimized new sequences can achieve a 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n \in N$ </tex-math></inline-formula> ) ratio of the switching frequency over envelope bandwidth. However, each increase of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> by 1 means that a whole set of voltage cells is added, leading to a great increase in system complexity and cost, especially for high peak-to-average power ratio (PAPR) applications. Besides, due to the irregular and aperiodic feature of the real communication envelope, the PEID control logic may suffer from surplus and imbalance in switching frequency reduction. Thus, this article proposes an improved PEID method. Assisted by the digital control platform, the control logic is redesigned, which can realize a balanced distribution of the rising and falling edges for arbitrary envelopes. Moreover, it can extend the domain of the “ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> ” to noninteger, achieving a more subtle resolution of PEID. On this basis, an evaluation function is constructed taking into account the efficiency, voltage-cell quantities, and switching frequency. With the desired weighted coefficients, an optimized comprehensive performance can be achieved. A prototype with 2–27-V output voltage range, 10- and 20-MHz tracking bandwidths, and 8.5-dB PAPR is fabricated and tested in the lab. The experimental results validate the proposed method.

On the Calibration of a Numerical Model for Concrete-to-Concrete Interface.

The study was devoted to the numerical modelling of concrete-to-concrete interfaces. Such an interface can be found in many modern composite structures, so proper characterisation of its behaviour is of great importance. A strategy for calibration of a model based on cohesive finite elements and the elastic-damage traction–separation constitutive law available by default in the Abaqus code was proposed. Moreover, the default interface material model was enhanced with the user-field-variables subroutine to include a real strength envelope for such interfaces. Afterwards, the modelling approach was validated with numerical simulation of the most popular tests for determining the strength characteristics of concrete-to-concrete interfaces: three-point bending beam with a notch, splitting bi-material cubic specimens, and slant-shear tests. The results of own pilot studies were used as well as those reported by other researchers. The performed simulations proved the accuracy of the proposed modelling strategy (the mean ratio of ultimate forces obtained with numerical models and from experiments was equal to 1.01). Furthermore, the presented examples allowed us to better understand the basic test methods for concrete interfaces and the observed mechanisms of failure during them.

The Conditions of Undercut By Shaping Using a Rounded Profile Gear Shaper Cutter

Abstract The present paper deals with the cases of undercut when not only the linear but the curved segment of the generatrix curve is also taken in consideration. The literature admits the approximation of the root fillet with a circular arc with a radius of 0,38 m. In this paper, instead of this approximation, the real envelope realized by the rounded rack-head is computed. In analyzing the undercut there are two classical synthetic geometrical models supporting Litvin’s general equations that describe the condition of avoiding the undercut: one for the linear and one for the rounded part of the generatrix. The scope of exact computing of the root fillet curve consists in optimizing the cutting toll tooth topland geometry to obtain the best rigidity. The numerically evaluated models allow us to conclude that profile shifting can be pushed below the undercut limits stated in the classical literature, without the appearance of the well-known fracture point on the meshed tooth profile.

Presentation of the Book The Gröbner Cover

The aim of this paper is to present the research book “The Grobner Cover” Montes (The Grobner Cover, ACM-series, Springer, Berlin, 2019) recently published. This book is divided into two parts, one theoretical and one focusing on applications, and offers a complete description of the Canonical Grobner Cover, to the author’s best knowledge, the most accurate algebraic method for discussing parametric polynomial systems. It also includes applications to the automatic deduction of geometric theorems, loci computation and envelopes. The theoretical part is a self-contained exposition on the theory of Parametric Grobner Systems and Bases. It begins with Weispfenning introduction of Comprehensive Grobner Systems (CGS), a fundamental contribution made in 1992, and provides a complete description of the Canonical Grobner Cover (GC), which includes a canonical discussion of a set of parametric polynomial equations developed in Montes, Wibmer (J Symb Comput 45:1391–1425, 2010). In turn, the application part selects three problems for which the Grobner Cover offers valuable new perspectives. The automatic deduction of geometric theorems (ADGT) becomes fully automatic and straightforward using GC, representing a major improvement on all previous methods. In terms of loci and envelope computation, GC makes it possible to introduce a taxonomy of the components and automatically compute it. The book also generalizes the definition of the envelope of a family of hyper-surfaces, and provides algorithms for its computation, as well as for discussing how to determine the real envelope. All the algorithms described in the book have also been included in the Singular software library grobcov.lib implemented by the author and H. Schonemann, the book serving also as User Manual for the library.

High Bandwidth and Compact Envelope Tracking Power Supply Utilizing Switched Capacitor Topology

The envelope tracking (ET) power supply has emerged to improve the efficiency of the power amplifier (PA) by supplying a variable voltage that tracks the envelope of the input signal to the PA. Represented by 5G, the future wireless communication technologies are characterized by higher envelope bandwidth and lower base station profile, which puts demanding requirements on ET power supply design. This paper investigates the key features of the switched capacitor topology and the pulse edge independent distribution (PEID) method, and then incorporates them into a unitary ET power supply. Comparing with the regular switched capacitor converter, this ET power supply can only involve minor changes in basic topology, which maintains a compact structure and preserves the merits of the original system being easy to drive. Besides, the corresponding control logic and control sequences are optimally redesigned, which can reduce the switching frequency to 1/n (n ∈ N) of the tracking bandwidth and extend the possible too narrow control pulses. To verify the proposed high bandwidth and compact ET power supply, a prototype with 6-26-V output voltage and 21-W peak output power is fabricated. The experiments are carried out by tracking a 1-MHz sine wave and a 5-MHz bandwidth real communication envelope, the results of which validate the proposed configuration and control scheme.

Geometrical and computer modeling of the technical workpieces main objects shaping

Geometrical and computer modeling of the main objects of technical workpieces shaping is considered: envelope, real envelope and removable layers based on the common methodology. The carried out research of two-dimensional surfaces and three-dimensional hyper-surfaces discriminants allowed to offer a definition of the envelope and real envelope families of curvatures and surfaces from a single viewpoint of analytical and numerical methods, respectively. This methodology is developed to perform 3D-modeling by means of CAD tools of both an envelope curvature and removable layers. The obtained surface models are used for analyzing the influence on the envelope shape of the of the of shape parameters profile family of the shaping curvature, as well as the parameter of setting a product relatively to the tool.

FY2018–FY2020 Medium-Term Budget

The Fund has been operating under a flat real resource envelope for the past six years. With continued efforts to maximize the use of available resources, spending in FY 17 is projected to reach 99 percent of the net administrative budget, and a low vacancy rate has helped stabilize overtime at 11 percent. Internal savings and reallocations have allowed the Fund to dedicate more resources to country work, including capacity development, without requiring an increase in the approved budget—apart from $6 million provided in FY 17 to cover rising security costs. An unchanged real net administrative budget in FY 18, despite deeper Fund engagement in a number of areas, as well as increased costs for corporate modernization. Accordingly, the budget proposal incorporates significant savings from reallocations and efficiency gains to fund new demands, as well as a further increase in the upfront allocation of carry-forward funds by about $10 million. The broad themes of the proposal are: (i) more intensive country work with a shift from surveillance to programs, but net savings in field offices; (ii) significant policy and analytical work on the financial sector and the role of the Fund (global safety net, facilities, and quotas), albeit less than in FY 17, with more work on structural issues and new challenges; (iii) funding for transforming IT and HR services, offset by central savings; and (iv) enhanced risk mitigation and knowledge management (KM), with the establishment of a KM unit to support cross-country analysis and knowledge transfer. At this stage, a flat resource envelope is assumed also for the medium term, contingent on continued reprioritization and a broadly unchanged global economic environment. Upward pressure on resources will arise from growing capacity development activities and certain revenue losses. Savings are expected from the TransformIT initiative and internal efficiency gains. But for the budget to remain flat, the Fund will need to continuously reprioritize and adjust its activities to make room for new demands. Even then, a more challenging global environment, with a further ramping up of Fund lending, or significant demands for deeper engagement in other areas, would put significant strains on resources over the medium term. The proposed capital budget envelope for FY 18–20 remains broadly unchanged from current levels. Some frontloading, however, is planned for the first two years, due to the cyclical nature of these investments and to accommodate strategic IT projects.

Performance assessment of façade integrated glazed air solar thermal collectors

Present trends on solar thermal systems for building integration define the need of integrated solar technologies for façades. The integration of solar systems in façades allows for the direct connection of solar systems to heated spaces, and automated air solar collectors based on the trombe-mitchell provide a suitable technology for its adoption in multi-rise buildings with decentralized-individual HVAC systems in Central-European and Mediterranean heating dominated climates.This paper reviews the main principles of such building envelope components, and the construction and design considerations of two air-based solar thermal collectors. Full scale preliminary prototypes of these systems were tested at the KUBIK by Tecnalia test facility in an Oceanic Climate (Koppen Geiger Cfb zone). The observed thermal performance is analyzed, and the process of a full scale installation in a real building envelope retrofitting process of a building in Spain is reviewed.

The Consolidated Medium-Term Income and Expenditure Framework

The medium-term income projections have been updated from the April 2015 outlook and the February review of the adequacy of precautionary balances. The main changes to the outlook stem from a more gradual rise in the SDR interest rates and lower surcharge income following the lowering of the surcharges threshold. The revised projections still show a positive forecast for net operational income (and surcharges) over the medium term, albeit lower than projected a year ago. Lending income (excluding surcharges) is marginally higher compared with earlier estimates. Surcharge income is estimated to be lower, reflecting the adjustment of the surcharges thresholds following the implementation of quota increases under the 14th General Review. Projected income from the Fixed-Income Subaccount of the Investment Account and interest-free resources are expected to increase more gradually over the medium-term as market indicators now point to a slower rise in interest rates from their current low levels. The expenditure path includes an increase in real terms of about ½ percent in the net administrative budget for FY 2017 to accommodate rising costs for physical and IT security. Moreover, reflecting further upward pressure over the medium term and uncertainty about the scope for offsetting savings, the traditional baseline assumption of a constant real spending envelope in the outer years is complemented by an alternative scenario with a further moderate spending increase of 1½ percent, phased in over FY 2018–19. In addition, a lower projected U.S. dollar/SDR exchange rate increases the expenses in SDR terms.

Considerations on elliptical failure envelope associated to Mohr-Coulomb criterion

Mohr-Coulomb theory is mostly used in civil engineering as it is suitable for soils, rock, concretes, etc., meaning that the theory is generally used for brittle facture of the materials, but there are cases when it matches ductile behaviour also. The failure envelope described by the Mohr-Coulomb criterion is not completely accurate to the real yield envelope. The ductile or brittle behaviour of materials could not be incorporated in a linear envelope suggested by classic stress state theories and so, there have been a number of authors who have refined the notion of yield envelope so that it would fit better to the actual behaviour of materials. The need of a realistic yield envelope comes from the demand that the failure state should be able to be predicted in a fair manner and with as little errors as possible. Of course, certain criteria will be closer to the actual situation, but there is a constant need to unify and refine the limit stress theories in order to avoid problems as defining boundaries of application areas on numerical programs. Mohr-Coulomb's yield envelope is the most used one on programs, can be reduced to Tresca theory when the materials are conducting a ductile behaviour and has a linear simplified form. The paper presents some considerations with respect to the elliptical failure envelope correlated to the Mohr-Coulomb theory. The equations have been rewritten for triaxial situation to describe a more accurate state of stress that is encountered under real conditions in materials. Using the Mohr's circles to define the yield envelope, the calculus has been made in in order to determine the yield stress at tensile tests

FY2016 - Output Cost Estimates and Budget Outturn Paper

Operating within a flat real budget envelope, the Fund delivered on the priorities and initiatives laid out in the Global Policy Agenda and Management’s Key Goals (MKGs). Resource pressures were addressed via implementation of streamlining initiatives, strategic reallocation of resources towards higher priority areas, and careful budget management. In terms of outputs, spending in FY 16 continued the shift from crisis management to crisis prevention, in line with the MKGs. Output shifted moderately from multilateral surveillance and oversight of the global system to bilateral surveillance and capacity development. Lending activity expenditure remained broadly unchanged. Average country spending was broadly aligned with assessment of risk. The net administrative budget outturn in FY 16 was $1,038 million against an approved budget of $1,052 million. The modest underspend reflects the preservation of the contingency reserve and lower-than-planned travel expenditure. Relative to FY 15, higher budget execution led to a small real (0.8 percent) year-on-year increase in net expenditures. Total capital expenditures of $131 million were recorded in FY 16 out of the $435 million in available appropriations. HQ1 Renewal expenses made up 70 percent of the spending.

FY2016 - FY2018 Medium-Term Budget

For the net administrative budget, the FY 16–18 medium-term budget (MTB) proposal includes: In FY 16, an unchanged budget envelope in real terms, for the fourth year in a row. To accommodate new and ongoing strategic priorities of the Fund within a flat envelope, efforts to reallocate resources away from lower-priority activities and achieve efficiency gains were stepped up both at the departmental level and across the institution. Savings measures implying a reallocation of resources of close to 5 percent of the net administrative budget were identified through this process. The bulk of these savings would be used to help meet the new priorities highlighted in the Global Policy Agenda and in Management’s Key Goals, while preserving room at the departmental level to further reduce work pressures, phase in the new streamlining measures and, more generally, cope with business uncertainties and unanticipated demands. This robust prioritization effort implies difficult trade-offs and the willingness to cut lower-priority activities in order to create space for new initiatives. For FY 17–18, as a baseline assumption, a flat real budget envelope as well. Against the backdrop of a robust income position, the Fund’s medium-term budget formulation is guided primarily by considerations of prudence and credibility. The medium-term spending path will depend on new demands placed on the institution, and the scope for further reprioritization, and will be reassessed in the context of the FY 17–19 budget.

A method to identify aperiodic disturbances in the ionosphere

Abstract. In this paper, variations in the ionospheric F2 layer's critical frequency are decomposed into their periodic and aperiodic components. The latter include disturbances caused both by geophysical impacts on the ionosphere and random noise. The spectral whitening method (SWM), a signal-processing technique used in statistical estimation and/or detection, was used to identify aperiodic components in the ionosphere. The whitening algorithm adopted herein is used to divide the Fourier transform of the observed data series by a real envelope function. As a result, periodic components are suppressed and aperiodic components emerge as the dominant contributors. Application to a synthetic data set based on significant simulated periodic features of ionospheric observations containing artificial (and, hence, controllable) disturbances was used to validate the SWM for identification of aperiodic components. Although the random noise was somewhat enhanced by post-processing, the artificial disturbances could still be clearly identified. The SWM was then applied to real ionospheric observations. It was found to be more sensitive than the often-used monthly median method to identify geomagnetic effects. In addition, disturbances detected by the SWM were characterized by a Gaussian-type probability density function over all timescales, which further simplifies statistical analysis and suggests that the disturbances thus identified can be compared regardless of timescale.

Exchanged ridge demodulation of time-scale manifold for enhanced fault diagnosis of rotating machinery

The vibration or acoustic signal from rotating machinery with localized fault usually behaves as the form of amplitude modulation (AM) and/or frequency modulation (FM). The demodulation techniques are conventional ways to reveal the fault characteristics from the analyzed signals. One of these techniques is the time-scale manifold (TSM) ridge demodulation method with the merits of good time–frequency localization and in-band noise suppression properties. However, due to the essential attribute of wavelet ridge, the survived in-band noise on the achieved TSM will still disturb the envelope extraction of fault-induced impulses. This paper presents an improved TSM ridge demodulation method, called exchanged ridge demodulation of TSM, by combining the benefits of the first two TSMs: the noise suppression of the first TSM and the noise separation of the second TSM. Specifically, the ridge on the second TSM can capture the fault-induced impulses precisely while avoiding the in-band noise smartly. By putting this ridge on the first TSM, the corresponding instantaneous amplitude (IA) waveform can represent the real envelope of pure faulty impulses. Moreover, an adaptive selection method for Morlet wavelet parameters is also proposed based on the smoothness index (SI) in the time-scale domain for an optimal time-scale representation of analyzed signal. The effectiveness of the proposed method is verified by means of a simulation study and applications to diagnosis of bearing defects and gear fault. • An improved time-scale manifold (TSM) ridge demodulation method is proposed. • The new method combines the benefits of the first two TSMs. • The parameters of Morlet wavelet are optimized for TSM learning. • The in-band noise can be eliminated in the extracted envelope. • The enhanced performance is verified in fault diagnosis of rotating machinery.

Research on Integrated Aircraft Modeling for Enhancing Accuracy of Flight Control System Design and Simulation

In order to realize excellent flight control system design and simulation, it is indispensable to establish a more realistic and more integrated aircraft model, so a scheme for an integrated aircraft model which consists of flight dynamics, propulsion system and flight environment is proposed in this research. Three parts of the integrated aircraft model are closely connected and interacted with each other. Furthermore, the aero engine model can reflect the engine thrust changes in the full real flight envelope and gains great parsimoniousness, which is designed based on K-means clustering algorithm and recursive reduced least squared vector regression. Simulation results confirm the effectiveness and preciseness of the integrated aircraft model. It also indicate to the control system designers that flight control system should be integrated with propulsion control, and the robustness and adaptivity of the flight control system should be paid much more attention to, so as to overcome the adverse effects of the flight environment.

About macroscopic models of instability pattern formation

Various macroscopic models to describe instability pattern formation are discussed in this paper. They are similar to the Ginzburg–Landau envelope equation, but they can remain valid away from the bifurcation and are based on the technique of Fourier series with slowly varying coefficients. We focus on two questions: the need to take phase changes into account and the boundary conditions to be associated with macroscopic models. The analysis is carried out on the basis of numerical simulations for the problem of a compressed beam on a nonlinear foundation that is quite similar to the well known Swift–Hohenberg equation. The first macroscopic model involves a real envelope so that the phase is assumed to be constant. The second model is also macroscopic and it is a sort of Ginzburg–Landau equation with a complex envelope. The third one follows from a multi-scaled approach with a numerical bridging between the full model near the boundary and a macroscopic model in the bulk.