Cleaning for Improved Indoor Air Quality: an Initial Assessment of Effectiveness

Abstract A study was conducted to characterize the indoor environment of a multifloor, multiuse, nonproblem, noncompliant building through long-term monitoring for biological, chemical, and particulate pollutants. The study also assessed the effects of cleaning on indoor air quality by providing a program to monitor baseline levels, providing a rigorous (deep) cleaning of the building, and then continuing to monitor after implementation of a standardized, improved, cleaning program. To assess the effectiveness of the cleaning program, air, surface, and dust data from monitoring prior to the cleaning program were compared with those obtained while the improved housekeeping program was in place. Correlations between pollutants and other environmental factors were studied. The data suggest that the improved cleaning program contributed to indoor air quality through the reduction of airborne dust mass, total volatile organic compounds, and culturable bacteria and fungi.     

Evaluation of calcium hydroxide contents in pozzolanic cement pastes by a chemical extraction method

The aim of the study is to investigate the calcium hydroxide (Ca(OH)₂) contents in pozzolanic cement pastes analyzed by the chemical extraction method and thermal analysis (DTA/TG). The second part of the study involves the carbonation of pozzolanic cement pastes and its influence on Ca(OH)₂ reduction. The Ca(OH)₂ contents in cement pastes after being subjected to accelerated carbonation were investigated by a chemical extraction method and compared to those values from DTA/TG analysis. The experimental results show that the chemical method reveals overall results comparable to those from DTA/TG analysis. However, in case of pastes containing high amounts of mineral admixtures or pastes subjected to carbonation which contain very low Ca(OH)₂, only the chemical method yields precise reliable results by showing the pseudo-negative contents.     

The nature and impacts of fines in smelter-grade alumina

Fines in smelter-grade aluminas are recognized as a significant process problem in aluminum smelting. However, understanding the nature of this fine material and how it impacts the reduction process are less clearly understood. The combination of new analytical methods such as variable pressure scanning electron microscopy and very high field solid state nuclear magnetic resonance provide new insights into the phases present and their spatial distribution within aluminas, and suggest how such fine materials are generated, particularly during calcination in the alumina refinery.     

Integrated-optic polarisation convertor on (001)-InP substrate

A novel TE/TM convertor is proposed and demonstrated which is fabricated on (001)-InP substrate and can be integrated with TE-TM phase shifters to provide a general polarisation transformation. Some aspects of the technological realisation and first results are given; in a first attempt, a polarisation rotation of about 20 deg by 20 V could be demonstrated.     

Enantioselective hydrogenation of ethyl pyruvate Long-term performance of chirally modified Pt/zeolite catalysts

The long-term performance of 5 wt.% Pt/zeolite catalysts (HNaY with different degrees of ion exchange) modified with (−)cinchonidine was studied. The enantioselective hydrogenation of ethyl pyruvate to R(+)ethyl lactate was used as the model reaction. The Pt/zeolites are effective catalysts for long-term use, if the chiral modifier is added before each cycle of hydrogenation. The optimal ratio between the amount of catalyst and chiral modifier essentially depends on both the specific Pt surface area of the catalyst and the solvent used. It is found that the use of acetic acid as solvent results in a higher long-term performance than cyclohexane. This is due to the competitive adsorption between the chiral auxiliary and acetic acid on the Pt surface. Furthermore, the acidity of the solvent results in a weakening of the (−)cinchonidine/Pt interaction, which prevents an overloading of the Pt surface area with (−)cinchonidine or its decay products. This effect was determined by means of differential thermal analysis and elemental analysis. When cyclohexane is used as the solvent, the long-term performance is significantly improved by raising the carrier acidity.     

Thermomechanische Behandlung von Manganhartstählen

Die durch Walzen oder Schmieden im Bereich von 700 bis 1050°C thermomechanisch behandelten Manganhartstähle X 120 Mn 12 und X 120 MnCrSiV 12 werden unter Einbeziehung einer anschließenden Haltedauer bei Umformtemperatur bzw. bei 440°C bezüglich ihres Gefüges und ihrer Eigenschaften vergleichend untersucht. Es zeigt sich, daß die Legierungszusätze an Chrom, Silicium und Vanadin eine höhere Umformtemperatur zur Erzielung einer gewünschten Verfestigung zulassen und damit die thermomechanische Behandlung erleichtern. Der Verschleißwiderstand wird nicht beeinträchtigt.     

Holzbrücken – Erkenntnisse zum Feuchteverhalten in den Tragquerschnitten aus Langzeitmessungen

Timber bridges – Long term monitoring results of moisture diffusion in the load carrying cross‐sections Timber road bridges have been built worldwide for centuries. The high performance of wood is approved through many constructions. However, there are still doubts about using wood by the planning engineer, which reduce the number of realized projects. The moisture induced stresses in cross‐sections according to the varied ambient climate are mainly investigated under laboratory conditions. The results show that the moisture content changes differently over the cross‐section and leads to moisture induced stresses. The discussion about methods for the assessment of the moisture induced stresses in timber bridge cross‐ections is continuing. Results observed in the long term monitoring of seven timber bridges provide first guidelines for practitioners. For all constructions, the moisture content was measured regarding the ambient micro climate. As result, the influences according to the ambient micro climate are not insignificant. Positive is that the directly measured moisture content is less compared to the equilibrium moisture content calculated from the data of a close by meteorological station. The analysis of the moisture gradient over the cross‐section allows the definition of an active or passive zone.     

Evaluation of potential human health risk associated with consumption of edible products from livestock fed ration supplemented with Red Lake Diatomaceous Earth

ABSTRACT

Red Lake Diatomaceous Earth (DE) is a naturally occurring blend of diatomaceous earth and calcium bentonite that can be used as an anti-caking agent in animal feed and contains naturally occurring dioxins. A quantitative risk assessment was conducted to assess potential human health risk associated with consumption of edible tissues from livestock exposed to dioxins via feed containing Red Lake DE. Empirical data characterising the transfer of dioxins to eggs and other tissues in chickens demonstrate that resulting concentrations in eggs are lower than those found in the general food supply. These data also provided product-specific input for a risk assessment conducted both with default parameters and with media-specific input from the feed study. Results demonstrate that exposure to dioxins in edible tissue from livestock that consumed Red Lake DE in feed would not be associated with an increased risk to humans. Findings from this assessment highlight the utility and importance of accounting for bioavailability as part of health-based risk assessment and provide information critical to risk managers in determining the safe use of Red Lake DE as an anticaking agent in livestock and pet feed.