Impact of adaptive comfort criteria and heat waves on optimal building thermal mass control

This article investigates building thermal mass control of commercial buildings to reduce utility costs with a particular emphasis on the individual impacts of both adaptive comfort criteria and of heat waves. Recent changes in international standards on thermal comfort for indoor environments allow for adaptation to the weather development as manifested in comfort criteria prEN 15251.2005 and NPR-CR 1752.2005 relative to the non-adaptive comfort criterion ISO 7730.2003. Furthermore, since extreme weather patterns tend to occur more frequently, even in moderate climate zones, it is of interest how a building's passive thermal storage inventory responds to prolonged heat waves. The individual and compounded effects of adaptive comfort criteria and heat waves on the conventional and optimal operation of a prototypical office building are investigated for the particularly hot month of August 2003 in Freiburg, Germany. It is found that operating commercial buildings using adaptive comfort criteria strongly reduces total cooling loads and associated building systems energy consumption under conventional and building thermal mass control. In the case of conventional control, total operating cost reductions follow the cooling loads reductions closely. Conversely, the use of adaptive comfort criteria under optimal building thermal mass control leads to both lower and slightly higher absolute operating costs compared to the optimal costs for the non-adaptive ISO 7730. While heat waves strongly affect the peak cooling loads under both conventional and optimal building thermal mass control, total cooling loads, building energy consumption and costs are only weakly affected for both control modes. Passive cooling under cost-optimal control, while achieving significant total cost reductions of up to 13%, is associated with total energy penalties on the order of 1–3% relative to conventional nighttime setup control. Thus, building thermal mass control defends its cost saving potential under optimal control in the presence of adaptive comfort criteria and heat waves.     

Recent water quality trends in the Schuylkill River,Pennsylvania, USA: a preliminary assessment of the relative influences of climate,river discharge and suburban development

Climate, flow rate and land use are all known drivers of water quality in river systems, but determining the relative influences of these factors remains a significant challenge for aquatic science and management. Long-term data from the Schuylkill River at Philadelphia is assessed here in an attempt to ascertain the separate and combined influence of these major drivers on water quality in a developed watershed. Water quality measures including nutrients, conservative solutes and bacteria all elicited distinct seasonal patterns driven primarily by river discharge. Mass transport rates of sodium and chloride have increased with time, and were elevated in winter, presumably as a function of road salt deposition. A steady increase in developed land area in the watershed has occurred in recent decades, which allowed the use of time as a surrogate parameter for regional development in the construction of multiple factor linear models predicting the relative influences of precipitation, river discharge and developed land area on river water quality. Linear models predicting annually averaged water quality measures showed the effects of precipitation, discharge and developed land area to be of nearly equal importance in regulating levels of conductivity, alkalinity, sodium, and chloride in the river. Models predicting water quality variables for discrete samples demonstrated that river flow was the major determinant of daily variability in alkalinity, conductivity, hardness and calcium levels, while still resolving the highly significant influence of watershed development on water quality. Increases in solute transport in the Schuylkill River in recent decades appear to be the direct result of modern suburban development in the watershed.     

Quantitative Analysis of the Leakage of Confidential Data

Basic information theory is used to analyse the amount of confidential information which may be leaked by programs written in a very simple imperative language. In particular, a detailed analysis is given of the possible leakage due to equality tests and if statements. The analysis is presented as a set of syntax-directed inference rules and can readily be automated.     

Retention of the high optical absorptance in thermally aged black chrome on variably sensitized Cu

The chemical composition, morphology, selective absorber characteristics, and degradation of selective absorber characteristics at high temperatures of black chrome solar selective coating are influenced by various substrate pre-treatments like mechanical polishing, chemical etching, and electropolishing prior to film deposition. The major oxide content in the deposit is formed as Cu₂(OH)₂CrO₄ (JCPDS 38-0230), which on high temperature annealing decomposes to CuCrO₄ (JCPDS 34-0507), CuO (JCPDS 41-0254), and Cu₂O (JCPDS 5-0667). Formation of the oxides of Cu at high temperatures retains the high optical absorption characteristics of the coating even after high temperature degradation.     

Microwave assisted HMDSO/oxygen plasma coated polyethylene terephthalate films: Effects of process parameters and uniaxial strain on gas barrier properties,surface morphology,and chemical composition

The coating structure and barrier property relation of coated PET films is of high interest for understanding the difference between predicted and actual barrier performance of coated PET films. In this work the chemical and morphological structure of HMDSO coatings generated with and without oxygen in a microwave plasma has been investigated with XPS and AFM analysis. These results were correlated with oxygen permeation measurements at different strain rates and temperatures. The results show that with a more glass‐like chemical composition the barrier property is improved. The growth of the coatings takes place in a columnar manner and the interfaces between the columns seem to be the low energy passages for the permeation, which cause the difference between predicted and actual barrier performance. When the coatings are strained the barrier fails at a strain higher than 1%. Cracks occur and with higher strain rates the number of cracks increases. Cracking takes place perpendicular to the strain direction and at the interfaces of the columns of the coating. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1485–1495, 2006     

Signieren mit Chipkartensystemen in unsicheren Umgebungen

Alle heutigen Implementierungen von HBCI sind durch Trojanische Pferde kompromittierbar: Vor diesem Hintergrund stellen die Autoren eine sichere HBCI-Variante mit Klasse-3-Lesern vor, die selbst bei einem kompromittierten PC nicht angreifbar ist.