Comparison of environmental impacts of two residential heating systems

This paper presents a comparison of environmental impacts of two residential heating systems, a hot water heating (HWH) system with mechanical ventilation and a forced air heating (FAH) system. These two systems are designed for a house recently built near Montreal, Canada. The comparison is made with respect to the life-cycle energy use, the life-cycle greenhouse gas (GHG) emissions, the expanded cumulative exergy consumption (ECExC), the energy and exergy efficiencies, and the life-cycle cost. The results indicate that the heating systems cause marginal impacts compared with the entire house in the pre-operating phase. In the operating phase, on the other hand, they cause significant environmental impacts. The HWH systems with a heat recovery ventilator (HRV) using either electricity or natural gas have the lowest life-cycle energy use and lowest ECExC. The HWH and FAH systems using electricity as energy source have the lowest GHG emissions. Finally, the FAH systems have, on the average, a lower life-cycle cost than the HWH systems.     

Inside looking out: a framework for discussing the question of architectural design doctorates

This text proposes a framework for provoking and sustaining a debate on the question of architectural design doctorates. Through a series of aphorisms it argues that the formal structure of architectural research should be defined by architects according to disciplinary specificity.

1. Architectural design is to architecture what research is to science.
2. The recognition of architectural design as research is more a problem of academic and social legitimisation than an epistemological one.
3. The process of architectural design is close to the process of knowledge creation in the sciences.
4. Architectural design is a process that incorporates and reconstructs knowledge.
5. The doctorate is a link in the chain of professional training of scientists as researchers and of architects as designers.
6. The ArchD is an opportunity to improve the practice of architecture.
7. The ArchD is an exploration of architectural design, the main tool of architects.
8. The Interface ArchD connects architectural design to theories and practices, to other forms of design and to other types of knowledge.
9. The Didactic ArchD contributes to the training of design professors, to the conversion of design knowledge into educational content and to innovation in learning environments in architecture.
10. The Self-reflective ArchD questions real or simulated practice, or proposes visionary designs.
11. There is no axiological difference between architectural design and scientific research.

     

SPECTRAL METHODS FOR HISTORICAL PAPER ANALYSIS: COMPOSITION AND AGE APPROXIMATION

The research has been focusing on some connection between the chemical composition of the papers obtained by Fourier transform infrared (FTIR) spectroscopy and the nature of the fillers, determined by energy dispersion X-ray fluorescence (EDXRF) spectroscopy. The present paper corroborates the FTIR and EDXRF results obtained for some historical papers from books of the XIX-th and XX-th centuries, from private collections. These analytical results allowed a first approximation of technological paper composition and of the age determination of the samples. This analytical method can elaborate some properly methods for paper documents preservation, taking into account the aging and degradation processes of the historical paper.     

Semi-fragile watermarking for image authentication with sensitive tamper localization in the wavelet domain

This paper proposes a novel image authentication scheme in the wavelet domain. The scheme uses a semi-fragile watermark to detect and precisely locate malicious tampering in images. The wavelet coefficients selected for embedding are randomly permuted with a secret key, achieving high security. A bit of the watermark is embedded in a group of coefficients by means of quantization. The experimental results show, that our algorithm achieves high image quality and high tampering detection resolution at a low watermark payload, compared to block-based authentication schemes. Thanks to the random permutation, the watermark is protected against local attacks. We have also conducted experiments to demonstrate the robustness of the watermark against mild to moderate JPEG compression.     

Thermal stability evaluation of polypropylene protected with grafted amine

Summary Polypropylene containing a grafted amine as oxidation protector was subjected to γ-irradiation for the evaluation of thermal stability. Several formulations were prepared containing hindered amine, Sanduvor PR 31 (0.1, 0.2 and 0.3% w/w) and CaCO₃ (0.6% w/w). The stability assessment was carried out in air by oxygen uptake procedure under isothermal and isobaric conditions (165 °C and normal pressure, respectively). The exposure doses were placed in the range from 0 to 70 kGy. The changes appeared in the main kinetic parameters (oxidation induction time and oxidation rate) evaluated for thermal degradation of irradiated PP specimens are presented and the stability analysis is explained starting from the behaviour differences of various formulations of radiation processed polypropylene. On the low dose range, the drop in thermal stability of modified polypropylene films occurs more abrupt than it was observed for the samples irradiated at higher doses.     

Fe-EDTA Thermal Decomposition,a Route to Highly Crystalline Hematite (Alpha Fe2O3) Nanoparticle Synthesis

In this study, we develop an experimental procedure to synthesize hematite nanoparticles by hydrothermal decomposition of Fe-EDTA complex in the presence of hydrogen peroxide, starting from ferric ammonium sulfate and Na ₄ EDTA as main precursors. The product was investigated by X-ray diffraction, scaning electron microscopy, dispersive X-ray spectroscopy, magnetic measurements, and UV-vis optical absorption measurements. The size of nanoparticles was determined to be 42 nm evaluated by XRD patterns using the Scherrer equation. This method allowed the formation of pure hematite nanoparticles with good and stable crystallographic characteristics. This procedure can be an effective method for synthesizing hematite nanoparticles exhibiting good crystallinity, stoichiometry, magnetic, and optical band gap properties. A possible mechanism for the formation of hematite nanocrystals was suggested.     

Influence of Charging Materials on the Rheological Behawor of High-Density Polyethylene Melts

The article presents the results of experimental studies on the rheological behavior of high-density polyethylene (HDPE) filled with calcium carbonate (25-125%) treated with surface-activating agents (a sort of high-density polyethylene with low molecular weight). Treating of the charge surface was realized by mixing (rapid Henschel mixer, 2 h, 60°C); then, the obtained recipes were submitted to granulation (Ko-Buss PR 40 type granulation installation). The rheological study was performed on a laboratory single-screw extruder especially equipped with a rheological nozzle having a measuring ring with four interchangeable bypasses. Six obtained recipes were processed in 28 regimes of shear rates, at a rotation speed ranging between 25 and 85 rpm and a temperature of 195°C. The influence of the filler on HDPE melts was investigated; it was established that the filler intensifies the viscous component, and for concentrations over 25%, it modifies the elastic component of the polymer substantially. The surface treating of the filler modifies the comportment of the matrix substantially: The tension threshold is reduced to elimination and the elastic component is strongly modified.     

Factors Influencing the Reversion of Stress-induced Martensite to Austenite in a Fe-Mn-Si-Cr-Ni Shape Memory Alloy

It is well known that one way shape memory effect (SME) in Fe-Mn-Si-based shape memory alloys (SMAs) is related to the thermally induced reversion of ε (hexagonal close packed, hcp) stress-induced martensite (SIM) to γ (face centered cubic, fcc) austenite. In the case of a Fe-Mn-Si-Cr-Ni SMA, this reverse martensitic transformation was analyzed in regard to the critical temperature for the beginning of austenite formation (A _s) in different states characterized by quenching temperature and permanent tensile strain. For this purpose, dynamic mechanical analysis (DMA), dilatometry (DIL), differential thermal analysis (DSC), and optical microscopy (OM) were employed to determine the influence of quenching temperature and permanent tensile straining on SIM reversion to austenite during heating.     

Analysis of current controllers for active power filters using selective harmonic compensation schemes

This paper presents a frequency response analysis of current controllers based on selective harmonic compensation schemes for three-phase voltage–source shunt Active Power Filters (APFs). To perform this analysis, the time delay introduced by the inverter and the sampling is taken into account in the current controller closed loop transfer function. Doing this, the differences among the schemes are pointed out, demonstrating the importance and effectiveness of the delay compensation to maintain the whole system stability. In addition, the performance of each current controller is evaluated by means of the total harmonic distortion of the mains line current and time response for fast load variations. The main goal is to identify the most suitable solution in terms of current controllers based on selective harmonic compensation for an industrial implementation. All the considered current control schemes have been tested on the same digital platform. Experimental results are presented for a 25-kVA shunt APF prototype compensating a nonlinear inductive load. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.